Patent Publication Number: US-2021163780-A1

Title: An acrylic polyester resin and an aqueous or powder coating composition containing the same

Description:
The present invention relates to an acrylic polyester resin and coating composition containing the same. The invention also relates to a metal packaging container having a coating on at least a portion thereof, the coating being derived from the coating composition. The invention also extends to methods of preparing the acrylic modified resin, methods of preparing the coating composition and methods of coating a metal packaging container. 
     A wide variety of coatings have been used to coat food and/or beverage containers. The coating systems typically have certain properties such as being capable of high speed application, having acceptable adhesion to the substrate, being safe for food contact and having properties that are suitable for their end use. Typically, coatings have one, or maybe two, of these advantageous properties depending on their final end use. 
     There is a desire for the coatings to be aqueous, rather than entirely solvent borne. However, many such coatings rely on the presence of a polyester material as a film forming resin, but polyester materials do not usually provide adequate solubility in water. Furthermore, aqueous coatings comprising polyester materials can display poor shelf life and poor coating qualities. There is also a desire for the coatings to be powder coatings. 
     It is an object the present invention to address the above mentioned or other problems. 
     According to the invention, there is provided an acrylic polyester resin, obtainable by grafting an acrylic polymer and a polyester material, the polyester material being obtainable by polymerizing:
         i) a polyacid component, with   ii) a polyol component,   wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   (x) an aliphatic polyacid or polyol monomer wherein the monomer comprises a tetracyclic hydrocarbon ring structure;   wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted with the polyester material via the use of said functionality,   and wherein the acrylic polyester resin has a Tg of at least 25° C.       

     According to the present invention, there is provided an aqueous coating composition or a powder coating composition, the coating composition comprising:
         a) an acrylic polyester resin, obtainable by grafting an acrylic polymer and a polyester material, the polyester material being obtainable by polymerizing:
           i) a polyacid component, with   ii) a polyol component, wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   
           (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro5.5]undecane-group containing polyacid or polyol;   (x) an aliphatic polyacid or polyol monomer wherein the monomer comprises a tetracyclic hydrocarbon ring structure;   wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted with the polyester material via the use of said functionality,   b) a crosslinking material,   and wherein a coating formed from the coating composition has a Tg of at least 25° C.       

     According to the present invention, there is provided a metal packaging container coated on at least a portion thereof with a coating, the coating being derived from an aqueous coating composition or a powder coating composition, the coating composition comprising:
         a) an acrylic polyester resin, obtainable by grafting an acrylic polymer and a polyester material, the polyester material being obtainable by polymerizing:
           i) a polyacid component, with   ii) a polyol component, wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   
           (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   (x) an aliphatic polyacid or polyol monomer wherein the monomer comprises a tetracyclic hydrocarbon ring structure;   wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted with the polyester material via the use of said functionality,   b) a crosslinking material,   and wherein the coating has a Tg of at least 25° C.       

     According to the present invention, there is provided a packaging coated on at least a portion thereof with a coating, the coating being derived from an aqueous coating composition or a powder coating composition, the coating composition comprising:
         a) an acrylic polyester resin, obtainable by grafting an acrylic polymer and a polyester material, the polyester material being obtainable by polymerizing:
           i) a polyacid component, with   ii) a polyol component,   
           wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   (x) an aliphatic polyacid or polyol monomer wherein the monomer comprises a tetracyclic hydrocarbon ring structure;   wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted with the polyester material via the use of said functionality,   b) a crosslinking material,   and wherein the coating has a Tg of at least 25° C.       

     Suitably, coating of the packaging is a cured coating. 
     Resistance properties of the coating derived from the aqueous coating composition or powder coating composition have been identified as being improved via the inclusion of a Tg enhancing monomer in the polyester material. 
     Suitably, the acrylic polyester resin comprises an acrylic modified polyester resin, which may be a polyester material having an acrylic polymer grafted thereonto. Suitably, the acrylic modified polyester resin may be prepared by grafting an acrylic polymer onto a preformed polyester material. Suitably, the acrylic modified polyester resin may be prepared by graft polymerising an acrylic monomer mixture onto a preformed polyester material. 
     The polyacid component or the polyol component comprises a functional monomer, operable to impart functionality to the polyester resin. The functionality is such that an acrylic polymer may be grafted onto the polyester material via the use of said functionality. The functionality may comprise ethylenic unsaturation, carboxylic acid functionality or epoxy functionality. The functionality may be in the backbone of the polyester material or pendant therefrom. 
     The functional monomer may comprise an ethylenically unsaturated monomer, which ethylenically unsaturated monomer may be operable to impart ethylenically unsaturated functionality on the backbone of the polyester resin, or pendant therefrom. Suitably, the functionality comprises ethylenic unsaturation, which may be in the backbone of the polyester material. 
     Suitable functional monomers may comprise: maleic acid, maleic anhydride, fumaric acid, itaconic anhydride, itaconic acid, citraconic anhydride, citraconic acid, aconitic acid, aconitic anhydride, oxalocitraconic acid, oxalocitraconic anhydride, mesaconic acid, mesaconic anhydride, phenyl maleic acid, phenyl maleic anhydride, t-butyl maleic acid, t-butyl maleic anhydride, monomethyl fumarate, monobutyl fumarate, nadic acid, nadic anhydride, methyl maleic acid, methyl maleic anhydride, and/or trimethylolpropane monoallyl ether. 
     Where the functional monomer is a polyacid, the functional monomer may be present as a proportion of the dry weight of the polyacid component in an amount of from 0.5 to 10 wt %, suitably from 1 to 5 wt %. 
     Where the functional monomer is a polyol, the functional monomer may be present as a proportion of the dry weight of the polyol component in an amount of from 0.5 to 10 wt %, suitably from 1 to 5 wt %. 
     Tg enhancing monomer means a monomer that raises the Tg of an acrylic polyester resin and/or coating formed from a coating composition compared to an acrylic polyester resin or coating composition that is the same except for not containing the Tg enhancing monomer. 
     The Tg enhancing monomer may comprise any combination of the Tg enhancing monomers (i) to (x). The Tg enhancing monomer may comprise:
         (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring,   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;       

     The Tg enhancing monomer may comprise:
         (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof; and/or   (vii) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol.       

     The Tg enhancing monomer may comprise:
         (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom,   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring,   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof; and/or   (vii) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol.       

     The Tg enhancing monomer may comprise:
         (iv) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (v) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom, and/or   (vi) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring.       

     The Tg enhancing monomer may comprise:
         (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof; and/or   (iii) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring.       

     The Tg enhancing monomer may comprise:
         (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol; and/or   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof.       

     The Tg enhancing monomer may be monomer (i): an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof. Tg enhancing monomer (i) may comprise 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, and/or hydrogenated 1,8 dihydroxy naphthalene, and/or esters and/or anhydrides of all the aforementioned acids. 
     The Tg enhancing monomer may be monomer (ii): a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom. Tg enhancing monomer (ii) may comprise hydrogenated bisphenol A, and/or 2-(2-carboxyphenyl)-benzoic acid, and/or esters and/or anhydrides of all the aforementioned acids. 
     The Tg enhancing monomer may be monomer (iii): an optionally substituted furan group-containing polyacid or polyol. Tg enhancing monomer (iii) may be 2,5 furandicarboxylic acid, and esters and anhydrides of all the aforementioned acids. 
     The Tg enhancing monomer may be monomer (iv): an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring. Tg enhancing monomer (iv) may comprise isosorbide, and/or isomannide. 
     The Tg enhancing monomer may be monomer (v): an optionally substituted bridged tricyclodecane group-containing polyacid or polyol. Tg enhancing monomer (v) may comprise tricyclodecane dimethanol, tricyclodecane diol, and/or tricyclocdecane polycarboxylic acid, and/or esters and/or anhydrides of all the aforementioned acids. 
     The Tg enhancing monomer may be monomer (vi): an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof. Tg enhancing monomer (vi) may comprise nadic methyl acid, nadic acid, and/or chlorendic anhydride, and/or esters and/or anhydrides/acids of all the aforementioned acids/anhydrides. 
     The Tg enhancing monomer may be monomer (vii): an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol. Tg enhancing monomer (vii) may comprise cyclohexane dimethanol, cyclohexane diol, 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, dimethyl-1,4-cyclochexane dicarboxylate, isophthalic acid, phthalic acid; isophthalic acid; 5-tert-butylisophthalic acid; tetrachlorophthalic acid; tetrahydrophthalic acid; hexahydrophthalic acid; methylhexahydrophthalic acid; endomethylene tetrahydrophthalic acid; endoethylene hexahydrophthalic acid; orthophthalic acid; phthalic anhydride; tetrahydrophthalic anhydride; dimethyl orthophthalate and/or terephthalic acid and/or esters and/or anhydrides of all the aforementioned acids. 
     The Tg enhancing monomer may be monomer (viii): a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms. Tg enhancing monomer (viii) may be neopentyl glycol. 
     The Tg enhancing monomer may be monomer (ix): an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol. Monomer (ix) may be 3,9-Bis(1,1-dialkyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, wherein alkyl is methyl, ethyl or propyl, suitably monomer (ix) is 3,9-Bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane. 
     The Tg enhancing monomer may be monomer (x): an aliphatic polyacid or polyol monomer. wherein the monomer comprises a tetracyclic hydrocarbon ring structure. Monomer (x) may comprise an aliphatic polyacid or polyol monomer comprising a saturated or partially unsaturated optionally substituted gonane. For example, the Tg enhancing monomer (x) may comprise androstenediol. 
     The acrylic polyester resin, the polyester material, aqueous coating composition, powder coating composition and/or the coating of the present invention may exclude 2,2,4,4-tetramethylcyclobutane-1,3-diol (“TMCD”). The definition of the Tg enhancing monomer may exclude 2,2,4,4-tetramethylcyclobutane-1,3-diol (“TMCD”). The definition of the polyol component may exclude 2,2,4,4-tetramethylcyclobutane-1,3-diol (“TMCD”). 
     The hydrogenated derivative of Tg enhancing monomer (i) may be fully or partially hydrogenated. As such, the hydrogenated derivative of (i) may be unsaturated. Suitably, the hydrogenated derivative of (i) is saturated. 
     The cyclic groups of Tg enhancing monomer (ii) may be aromatic or alicyclic. Monomer (ii) may comprise two optionally substituted 6 membered cyclic groups. Suitably, monomer (ii) comprises two optionally substituted 6 membered aromatic cyclic groups that are directly bonded. Suitably, monomer (ii) comprises two optionally substituted 6 membered alicyclic cyclic groups that are separated by one carbon atom, suitably, the alicyclic groups of monomer (ii) are cycloalkyl. “Directly bonded” when used herein means that a ring atom in one of the two cyclic groups is covalently bonded with a ring atom in the other cyclic group. 
     Monomer (iv) may comprise a heteroatom in a ring, suitably one heteroatom in each ring, and suitably the heteroatoms are oxygen or nitrogen atoms, such as oxygen atoms. 
     The optionally substituted bridged tricyclodecane group of monomer (v) may be saturated or unsaturated, suitably saturated. The optionally substituted bridged tricyclodecane group may be tricyclo[5.2.1.0(2,6)]decane. 
     The optionally substituted hydrogenated derivative of the optionally substituted bridged norbornene-group of monomer (vi) may be optionally substituted norbornane. 
     The optionally substituted 5 or 6 membered cycloalkyl group of monomer (vii) may be saturated or partly unsaturated, suitably saturated. 
     The branched alkyl group-containing monomer (viii) may be formed of from 5 to 8 carbon atoms, such as from 5 to 7 carbon atoms, 5 to 6 carbon atoms or 5 carbon atoms. 
     It will be understood that the optional substituents of the groups of the Tg enhancing monomers (i) to (vii) and (ix) are in addition to the acid and hydroxyl groups of the Tg enhancing monomers. The optional substituents of the Tg enhancing monomers may be alkyl or heteratom, such as lower alkyl, for example straight or branched alkyl formed of from 1 to 10 carbon atoms, such as from 1 to 5 carbon atoms or from 1 to 3 carbon atoms, suitably 1 or 2 carbon atoms, suitably 1 carbon atom. The heteroatom may be chlorine. Suitably, the optional substituent(s) may comprise methyl, ethyl and/or propyl, suitably methyl. 
     The Tg enhancing monomer may comprise 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, hydrogenated 1,8 dihydroxy naphthalene, hydrogenated bisphenol A, 2-(2-carboxyphenyl)-benzoic acid, 2,5 furandicarboxylic acid, isosorbide, isomannide, tricyclodecane dimethanol, tricyclodecane diol, tricyclocdecane polycarboxylic acid, nadic methyl acid, nadic acid, chlorendic anhydride, cyclohexane dimethanol, cyclohexane diol, 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, dimethyl-1,4-cyclochexane dicarboxylate, neopentyl glycol, 3,9-Bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, isophthalic acid, phthalic acid; isophthalic acid; 5-tert-butylisophthalic acid; tetrachlorophthalic acid; tetrahydrophthalic acid; hexahydrophthalic acid; methylhexahydrophthalic acid; endomethylene tetrahydrophthalic acid; endoethylene hexahydrophthalic acid; orthophthalic acid; phthalic anhydride; tetrahydrophthalic anhydride; dimethyl orthophthalate and/or terephalic acid and/or esters and/or anhydrides/acids of all the aforementioned acids/anhydrides. 
     The Tg enhancing monomer may comprise 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, hydrogenated 1,8 dihydroxy naphthalene, hydrogenated bisphenol A, 2-(2-carboxyphenyl)-benzoic acid, 2,5 furandicarboxylic acid, isosorbide, isomannide, tricyclodecane dimethanol, tricyclodecane diol, tricyclocdecane polycarboxylic acid, nadic methyl anhydride, nadic acid, chlorendic anhydride, nadic anhydride, cyclohexane dimethanol, cyclohexane diol, 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, dimethyl-1,4-cyclochexane dicarboxylate 3,9-Bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, isophthalic acid, phthalic acid; isophthalic acid; 5-tert-butylisophthalic acid; tetrachlorophthalic acid; tetrahydrophthalic acid; hexahydrophthalic acid; methylhexahydrophthalic acid; endomethylene tetrahydrophthalic acid; endoethylene hexahydrophthalic acid; orthophthalic acid; phthalic anhydride; tetrahydrophthalic anhydride; dimethyl orthophthalate and/or terephalic acid. 
     The Tg enhancing monomer may comprise 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, hydrogenated 1,8 dihydroxy naphthalene, hydrogenated bisphenol A, 2-(2-carboxyphenyl)-benzoic acid, 2,5 furandicarboxylic acid, isosorbide, isomannide, tricyclodecane dimethanol, tricyclodecane diol, tricyclocdecane polycarboxylic acid, nadic methyl anhydride, nadic acid, chlorendic anhydride, nadic anhydride 3,9-Bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, isophthalic acid, and/or terephalic acid. 
     The Tg enhancing monomer may comprise 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, hydrogenated 1,8 dihydroxy naphthalene, hydrogenated bisphenol A, 2-(2-carboxyphenyl)-benzoic acid, 2,5 furandicarboxylic acid, isosorbide, isomannide, tricyclodecane dimethanol, tricyclodecane diol, tricyclocdecane polycarboxylic acid, nadic methyl anhydride, nadic acid, nadic anhydride, and/or 3,9-Bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane. 
     The Tg enhancing monomer may comprise 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, hydrogenated 1,8 dihydroxy naphthalene, hydrogenated bisphenol A, 2-(2-carboxyphenyl)-benzoic acid, isosorbide, isomannide, tricyclodecane dimethanol, tricyclodecane diol, tricyclocdecane polycarboxylic acid, nadic methyl anhydride, nadic acid, and/or nadic anhydride. 
     The Tg enhancing monomer may comprise 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, hydrogenated 1,8 dihydroxy naphthalene, hydrogenated bisphenol A, 2-(2-carboxyphenyl)-benzoic acid, isosorbide, and/or isomannide. 
     The Tg enhancing monomer may comprise 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, hydrogenated 1,8 dihydroxy naphthalene, isosorbide, and/or isomannide. 
     The Tg enhancing monomer may comprise hydrogenated bisphenol A, and/or 2-(2-carboxyphenyl)-benzoic acid. 
     The Tg enhancing monomer may comprise tricyclodecane dimethanol, tricyclodecane diol, tricyclocdecane polycarboxylic acid, nadic methyl anhydride, nadic acid, and/or nadic anhydride. 
     The Tg enhancing monomer may comprise tricyclodecane dimethanol, tricyclodecane diol, nadic methyl anhydride, nadic acid, and/or nadic anhydride. 
     The amount of Tg enhancing monomer in the polyol and polyacid components may be the amount required to impart the desired Tg. For example, the amount of Tg enhancing monomer (i) to (x) in the polyol and/or polyacid components may be the amount required to achieve a Tg of at least 25° C., or a Tg of at least 40° C., or at least 50° C., such as at least 60° C. or at least 70° C. 
     The polyol and polyacid components may together comprise at least 10 mole % of a Tg enhancing monomer (i) to (x) wherein the total mole % of the combined polyol and polyacid components is 100 mole %. Suitably the polyol and polyacid components may together comprise at least 20 mole % of a Tg enhancing monomer (i) to (x), such as at least 30 mole %, at least 40 mole % or at least 50 mole %. 
     The polyol and polyacid components may together comprise at least 10 mole % of a Tg enhancing monomer (i) to (v) and/or (ix) wherein the total mole % of the combined polyol and polyacid components is 100 mole %. Such as at least 20 mole %, at least 30 mole %, at least 40 mole % or at least 50 mole %. 
     The polyol and polyacid components may together comprise at least 15 mole % of a Tg enhancing monomer (vi) and/or (viii), and/or (vii) when aromatic, wherein the total mole % of the combined polyol and polyacid components is 100 mole %, such as at least 20 mole %, at least 30 mole %, at least 40 mole % or at least 50 mole %. 
     The polyol and polyacid components may together comprise at least 20 mole % of a Tg enhancing monomer (vii) when cycloalkyl, wherein the total mole % of the combined polyol and polyacid components is 100 mole %, such as at least 30 mole %, at least 40 mole % or at least 50 mole %. 
     The polyacid component suitably comprises a polyacid, either in addition to a Tg enhancing monomer (i) to (x) or in the absence of a Tg enhancing monomer (i) to (x). “Polyacid” and like terms as used herein, refers to a compound having two or more carboxylic acid groups, such as two (diacids), three (triacids) or four acid groups, and includes an ester of the polyacid (wherein an acid group is esterified) or an anhydride. The polyacid is suitably an organic polyacid. 
     The carboxylic acid groups of the polyacid may be connected by a bridging group comprising: an alkylene group; an alkenylene group; an alkynylene group; or an arylene group. 
     The polyester material may be formed from any suitable polyacid, either in addition to a Tg enhancing monomer polyacid (i) to (x) or in the absence of a Tg enhancing monomer polyacid (i) to (x). Suitable examples of polyacids include, but are not limited to the following: maleic acid; fumaric acid; itaconic acid; adipic acid; azelaic acid; succinic acid; sebacic acid; glutaric acid; decanoic diacid; dodecanoic diacid; trimellitic acid; naphthalene tetracarboxylic acid; cyclohexanetetra carboxylic acid; cyclobutane tetracarboxylic; a monomer having an aliphatic group containing at least 15 carbon atoms; esters and anhydrides of all the aforementioned acids and combinations thereof. 
     The polyacid component may comprise a diacid, either in addition to a Tg enhancing monomer diacid (i) to (x) or in the absence of a Tg enhancing monomer diacid (i) to (x). Suitable examples of diacids include, but are not limited to the following: succinic acid; adipic acid; azelaic acid; sebacic acid; fumaric acid; maleic anhydride; succinic anhydride; itaconic anhydride; di-ester materials, such as dimethyl ester derivatives for example dimethyl isophthalate, dimethyl fumarate, dimethylsuccinate, dimethyl glutarate, dimethyl adipate; a monomer having an aliphatic group containing at least 15 carbon atoms; esters and anhydrides of all the aforementioned acids; and mixtures thereof. 
     Suitably, the polyacid component comprises: terephthalic acid (TPA), isophthalic acid (IPA), dimethyl isophthalic acid, hexahydrophthalic anhydride, phthalic anhydride, maleic anhydride, fumaric anhydride; and/or a monomer having an aliphatic group containing at least 15 carbon atoms, such as a dimer fatty acid, suitably a dimer fatty acid comprising 18 to 50 carbon atoms, such as a dimer fatty acid comprising 20 to 46 carbon atoms, or a dimer fatty acid comprising from 22 to 44 carbon atoms, for example a dimer fatty acid comprising from 24 to 42 carbon atoms, a dimer fatty acid comprising from 26 to 40 carbon atoms, a dimer fatty acid comprising from 28 to 38 carbon atoms, or a dimer fatty acid comprising from 30 to 38 carbon atoms. 
     Suitably, the polyacid component comprises: dimethyl terephthalate, hexahydrophthalic anhydride, cyclohexane 1,4-dicarboxylic acid and/or a monomer having an aliphatic group containing at least 15 carbon atoms, such as a dimer fatty acid, suitably a dimer fatty acid comprising 18 to 50 carbon atoms, such as a dimer fatty acid comprising 20 to 46 carbon atoms, or a dimer fatty acid comprising from 22 to 44 carbon atoms, for example a dimer fatty acid comprising from 24 to 42 carbon atoms, a dimer fatty acid comprising from 26 to 40 carbon atoms, a dimer fatty acid comprising from 28 to 38 carbon atoms, or a dimer fatty acid comprising from 30 to 38 carbon atoms, or comprises isophthalic acid, hexahydrophthalic anhydride, and/or a monomer having an aliphatic group containing at least 15 carbon atoms, such as a dimer fatty acid, suitably a dimer fatty acid comprising 18 to 50 carbon atoms, such as a dimer fatty acid comprising 20 to 46 carbon atoms, or a dimer fatty acid comprising from 22 to 44 carbon atoms, for example a dimer fatty acid comprising from 24 to 42 carbon atoms, a dimer fatty acid comprising from 26 to 40 carbon atoms, a dimer fatty acid comprising from 28 to 38 carbon atoms, or a dimer fatty acid comprising from 30 to 38 carbon atoms. 
     The polyol component suitably comprises a polyol, either in addition to a Tg enhancing monomer polyol (i) to (x) or in the absence of a Tg enhancing monomer polyol (i) to (x). “Polyol” and like terms, as used herein, refers to a compound having two or more hydroxyl groups, such as two (diols), three (triols) or four hydroxyl groups. The hydroxyl groups of the polyol may be connected by a bridging group comprising: an alkylene group; an alkenylene group; an alkynylene group; or an arylene group. Suitably the polyol is an organic polyol. 
     The polyester material may be formed from any suitable polyol, either in addition to a Tg enhancing monomer polyol (i) to (x) or in the absence of a Tg enhancing monomer polyol (i) to (x). Suitable examples of polyols include, but are not limited to the following: alkylene glycols, such as ethylene glycol; propylene glycol; diethylene glycol; dipropylene glycol; triethylene glycol; tripropylene glycol; hexylene glycol; polyethylene glycol; and/or polypropylene glycol cyclohexanediol; propanediols including 1,2-propanediol; 1,3-propanediol; butyl ethyl propanediol; 2-methyl-1,3-propanediol; and/or 2-ethyl-2-butyl-1,3-propanediol; butanediols including 1,4-butanediol; 1,3-butanediol; and/or 2-ethyl-1,4-butanediol; pentanediols including trimethyl pentanediol and/or 2-methylpentanediol; cyclohexanedimethanol; hexanediols including 1,6-hexanediol; caprolactonediol (for example, the reaction product of epsilon-capro lactone and ethylene glycol); hydroxyalkylated bisphenols; polyether glycols, for example, poly(oxytetramethylene) glycol; trimethylol propane; pentaerythritol; di-pentaerythritol; trimethylol ethane; trimethylol butane; dimethylol cyclohexane; bio-derived polyols such as glycerol, sorbitol; and/or a monomer having an aliphatic group containing at least 15 carbon atoms and the like or combinations thereof. 
     The polyol component may comprises a diol, either in addition to a Tg enhancing monomer diol (i) to (x) or in the absence of a Tg enhancing monomer diol (i) to (x). The polyol component may comprise any suitable diol. Suitable examples of diols include, but are not limited to the following: ethylene glycol; 1,2-propane diol; 1,3-propane diol; 1,2-butandiol; 1,3-butandiol; 1,4-butandiol; but-2-ene 1,4-diol; 2,3-butane diol; 2-methyl 1,3-propane diol; 1,5 pentane diol; 3-methyl 1,5-pentanediol; 2,4-diethyl 1,5-pentane diol; 1,6-hexane diol; 2-ethyl 1,3-hexane diol; diethylene glycol; triethylene glycol; dipropylene glycol; tripropylene glycol; 2,2,4-trimethyl pentane 1,3-diol; and/or 1,1′-isopropylidene-bis (4-cyclohexanol); and mixtures thereof. 
     The polyol component may comprise a polyol having at least three hydroxyl groups, such as trimethylol propane; pentaerythritol; di-pentaerythritol; trimethylol ethane; trimethylol butane; and/or bio-derived polyols such as comprising glycerol and/or sorbitol. Suitably, the polyol component having at least three hydroxyl groups comprises a triol or tetrol, such as trimethylol propane; pentaerythritol; trimethylol ethane; trimethylol butane and/or glycerol. More suitably, the polyol component having at least three hydroxyl groups comprises a triol, such as trimethylol propane; trimethylol ethane; and/or trimethylol butane, for example trimethylol propane. 
     The polyol having at least three hydroxyl groups may be present as a proportion of the dry weight of the polyol component in an amount of from 0.1 to 10 wt %, such as from 0.5 to 8 wt % or from 0.7 to 6 wt %, for example from 0.8 to 5 wt % or from 0.9 to 4 wt %, suitably from 1 to 3 wt % or from 1 to 2 wt %. 
     The polyol component may comprise: 2-methyl propanediol (2-MPD), butyl ethyl propane diol (BEPD), trimethylolppropane (TMP) and/or 1,6 hexanediol. 
     The polyol component may comprise a Tg enhancing monomer in combination with 2-methy-1,3-propanediol, suitably cyclohexanedimethanol in combination with a different Tg enhancing monomer and 2-methy-1,3-propanediol. 
     The polyol component may comprise a Tg enhancing monomer in combination with 2-methy-1,3-propanediol, and/or trimethylolpropane, suitably cyclohexanedimethanol in combination with a different Tg enhancing monomer, 2-methyl-1,3-propanediol and trimethylolpropane. 
     The aliphatic group of the monomer having an aliphatic group (aliphatic group-containing monomer) may comprise at least 18 or 20 carbon atoms, such as at least 22, 24, 26, 28 or 30 carbon atoms. The aliphatic group of the aliphatic group-containing monomer may contain up to 50 carbon atoms, such as up to 46 carbon atoms or up to 44, 42, 40 or 38 carbon atoms. 
     The aliphatic group of the aliphatic group-containing monomer may comprise from 18 to 50 carbon atoms, such as from 20 to 46 carbon atoms, from 22 to 44 carbon atoms, from 24 to 42 carbon atoms, from 26 to 40 carbon atoms, from 28 to 38 carbon atoms, or from 30 to 38 carbon atoms. 
     The aliphatic group of the aliphatic group-containing monomer may be linear, branched, cyclic, interrupted by a heteroatom such as oxygen, nitrogen and/or sulphur, substituted, saturated, and/or unsaturated. Suitably, the aliphatic group of the aliphatic group-containing monomer is branched. The aliphatic group of the aliphatic group-containing monomer may comprise a cyclic group. Suitably, the aliphatic group of the aliphatic group-containing monomer is saturated or monounsaturated. The aliphatic group of the aliphatic-group containing monomer may be branched and saturated. The aliphatic group of the aliphatic-group containing monomer may comprise a cyclic group and be saturated. The aliphatic group of the aliphatic group-containing monomer may have no substituents and/or not be interrupted by a heteratom. 
     The branching of the aliphatic group may be monoalkyl or polyalkyl, wherein “alkyl” when used in relation to monoalkyl or polyalkyl branching may be C 1  to C 15 , such as C 1  to C 10 , C 1  to C 8 , C 1  to C 5 , or C 1  to C 3 . Suitably the monoalkyl branching is methyl or ethyl or propyl or optionally a mixture thereof for polyalkyl branching. Suitably, the branching of the aliphatic group is polyalkyl. 
     The cyclic groups of the aliphatic group may be saturated or partially unsaturated cyclic aliphatic monocyclic or polycyclic ring systems which comprise from 3 to 20 carbon atoms, such as from 3 to 15, or from 3 to 12, or from 3 to 10, or from 3 to 8 carbon atoms, or from 3 to 6 carbon atoms. 
     The aliphatic-group containing monomer may comprise a ratio of acyclic carbon atoms to cyclic carbon atoms of at least 1:1, such as at least 2:1, at least 3:1, at least 4:1 or at least 5:1. By “cyclic carbon atoms” it is meant carbon atoms contained in a ring of a cyclic group. 
     The optional substituents of the aliphatic group of the aliphatic group-containing monomer may include aryl, halogen, cyano, nitro, OR 19 , OC(O)R 20 , C(O)R 21 , C(O)OR 22 , NR 23 R 24 , C(O)NR 25 R 26 , C(S)R 25 R 26 , SR 27 , C(O)SR 27 . Suitably, the optional substituents include C 6  to C 10  aryl, halogen, OR 19 , C(O)R 21 , and SR 27 . R 19  to R 27  each independently represent hydrogen, alkyl (such as C 1  to C 10  alkyl), or aryl (such as C 6  to C 10  aryl). 
     The aliphatic group-containing monomer may be formed of the aliphatic group radical joined to the carboxyl or alcohol groups of the polyacid or polyol. The aliphatic-group containing monomer may have no aromatic groups. 
     The aliphatic group-containing monomer may be a diacid or a diol. Suitably the aliphatic group-containing monomer is a diacid. 
     The aliphatic group-containing monomer may be the dimerisation product of mono- or polyunsaturated fatty acids, esters thereof, and/or fatty alcohols. Suitably, the aliphatic group-containing monomer is the dimerisation product of mono- or polyunsaturated fatty acids and/or esters thereof. The aliphatic group-containing monomer may be a dimer fatty acid (also known as dimer fatty diacid) or a dimer fatty alcohol (also known as dimer fatty diol). Suitably, the aliphatic group-containing monomer is a dimer fatty acid. 
     The aliphatic group-containing monomer may be a dimer fatty acid or alcohol comprising from 18 to 50 carbon atoms, such as a dimer fatty acid or alcohol comprising from 20 to 46 carbon atoms, or a dimer fatty acid or alcohol comprising 22 to 44 carbon atoms, for example a dimer fatty acid or alcohol comprising from 24 to 42 carbon atoms, or a dimer fatty acid or alcohol comprising from 26 to 40 carbon atoms, or a dimer fatty acid or alcohol comprising from 28 to 38 carbon atoms, or a dimer fatty acid or alcohol comprising from 30 to 38 carbon atoms. 
     The aliphatic group-containing monomer may be a dimer fatty acid comprising 18 to 50 carbon atoms, such as a dimer fatty acid comprising 20 to 46 carbon atoms, or a dimer fatty acid comprising from 22 to 44 carbon atoms, for example a dimer fatty acid comprising from 24 to 42 carbon atoms, a dimer fatty acid comprising from 26 to 40 carbon atoms, a dimer fatty acid comprising from 28 to 38 carbon atoms, or a dimer fatty acid comprising from 30 to 38 carbon atoms. 
     The aliphatic group-containing monomer may be the dimerisation product of erucic acid, α-linolenic acid, stearidonic acid, eicosapentaenoic acid docosahexaenoic acid, linoleic acid, linolelaidic acid, γ-linolenic acid, dihomo-γ-linolenic acid, arachidonic acid, docosatetraenoic acid, palmitoleic acid, vaccenic acid, paillinic acid, oleic acid, elaidic acid, gondoic acid, erucic acid, nervonic acid, and/or mead acid. 
     The aliphatic group-containing monomer may be the dimerisation product of erucic acid, linolenic acid, linoleic acid, and/or oleic acid. 
     Suitably, only one of the polyacid component or the polyol component comprises a monomer having an aliphatic group containing at least 15 carbon atoms, suitably the polyacid component comprises a monomer having an aliphatic group containing at least 15 carbon atoms. The polyester material may be a hydrophobic polyester material in which the polyacid component comprises a monomer having an aliphatic group containing at least 15 carbon atoms. 
     Suitably, the polyacid component and/or the polyol component comprises a sulfonated monomer. The sulfonated monomer may comprise a sulfonated diacid, such as a sulfonated aromatic diacid. The sulfonated monomer may comprise a salt thereof, such as an inorganic salt, for example a metal or ammonium salt. Examples of metal salts would include, for example sodium salts, lithium salts, potassium salts, magnesium salts, calcium salts, iron salts etc. 
     Suitably, the polyacid component comprises a sulfonated monomer. Alternatively, the polyacid component may be substantially free of sulfonated monomer. 
     Suitably, the sulfonated monomer may comprise a metal salt of 5-(sulfo)-isopthalic acid, such as the sodium salt thereof, referred to as 5-(sodiosulfo)-isophthalic acid, also referred to herein as 5-SSIPA. 
     Suitably, the sulfonated monomer comprises: 5-(sodiosulfo)-isophthalic acid, dimethyl 5-(sodiosulfo)isophalate, 5-(lithiosulfo)isophthalic acid, and/or bis(2-hydroxyethyl)-5-(sodiosulfo)isophthalate. 
     Where the sulfonated monomer is a polyacid, the sulfonated monomer may be present as a proportion of the dry weight of the polyacid component in an amount of from 5 to 20 wt %, such as 7 to 15 wt %. 
     Where the sulfonated monomer is a polyol, the sulfonated monomer may be present as a proportion of the dry weight of the polyol component in an amount of from 5 to 20 wt %, such as 7 to 15 wt %. 
     Suitably, the polyacid component comprises: dimethyl terephthalate, isophthalic acid, hexahydrophthalic anhydride, cyclohexane 1,4-dicarboxylic acid, and/or 5-(sodiosulfo)-isophthalic acid. 
     Suitably, the functional monomer comprises maleic acid, maleic anhydride and/or fumaric acid. 
     The polyester material is suitably modified with acrylic by grafting an acrylic modification polymer onto the polyester material. This grafting may occur via free radical polymerization, such as by free radical polymerization onto ethylenic unsaturation on the polyester material. 
     Suitably, the acrylic modification polymer is formed from acrylic monomers. Suitably, the acrylic modification polymer is grafted onto the polyester by polymerizing acrylic monomers in the presence of the polyester material to form the acrylic modified polyester resin. 
     Various acrylic monomers can be combined to prepare the acrylic modification polymer. Examples include methyl(meth)acrylate, ethyl(meth)acrylate, butyl (meth)acrylate, isobornyl (meth)acrylate, hydroxyethyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, (meth)acrylic acid, nitriles such as (meth)acrylonitrile. Any other acrylic monomers known to those skilled in the art could also be used. The term “(meth) acrylate” and like terms are used conventionally and herein to refer to both methacrylate and acrylate. A suitable acrylic modification polymer may be formed with: methyl (meth)acrylate, ethyl(meth)acrylate, butyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylic acid, cyclohexyl (meth)acrylate, allyl (meth)acrylate, dimethylamino ethyl methacrylate. butylamino ethyl (meth)acrylate, and/or HEMA phosphate (such as ethylene glycol methacrylate phosphate. 
     The acrylic monomers may comprise a ratio of methacrylate monomers to acrylate monomers of at least 1:1, such as at least 2:1 or at least 3:1 or at least 4:1, suitably at least 5:1. The acrylic monomers may be substantially free of acrylate monomers. By “methacrylate monomers” and “acrylate monomers” with regard to the ratio of these types of monomers in the acrylic monomers of the acrylic modification polymer, it is meant the total number of methacrylate monomers compared to the total number of acrylate monomers across all the types of acrylic monomer that form the acrylic modification polymer. For example, if the acrylic modification polymers is formed of methylmethacrylate, methyl acrylate and butyl acrylate, then the amount of methylmethacrylate compared to the combined amount of methyl acrylate and butyl acrylate would be at least 5:1. 
     The acrylic monomers may comprise a hydroxyl functional monomer, such as hydroxyethyl (meth)acrylate. Suitably, the hydroxyl functional monomer is present by dry weight of the acrylic modification polymer in an amount of from 5 to 40 wt %, such as from 5 to 30 wt % or from 10 to 20 wt %. 
     The acrylic modification polymer may also comprise an amount (from 0 to 30 wt %, by dry weight of the acrylic modification polymer) of non acrylic monomers. Such non acrylic monomers may include other ethylenically unsaturated monomers, such as styrene, ethylene, propylene, vinyl toluene, butadiene, 1-octene or isoprene, vinyl esters such as vinyl acetate. 
     It has been identified that the acrylic modification polymer may suitably include meth acrylic acid or acrylic acid to impart acid functionality on the acrylic modification polymer. Suitably, the acid functionality on the acrylic modification polymer may be at least partially neutralised with a neutralisation agent. 
     Suitable neutralisation agents include ammonia or amine functional moieties: methyl ethanolamine, dimethylethanolamine (DMEA), trimethylamine, diethylene triamine. 
     Suitably, the acid functionality on the acrylic modification polymer may be at least 50% neutralised with a neutralisation agent. Suitably, the acid functionality on the acrylic modification polymer may be at least 75% neutralised with a neutralisation agent. Suitably, the acid functionality on the acrylic modification polymer may be at least 90% neutralised with a neutralisation agent. 
     Where the polyester material of the acrylic modified polyester resin comprises a sulfonated monomer, neutralisation of the acrylic modified polyester resin may not be required. 
     The polyester material may have any suitable number-average molecular weight (Mn). The polyester material may have an Mn from 1,000 Daltons (Da=g/mole) to 15,000 Da, suitably from 2,000 Da to 10,000 Da, such as from 3,000 Da to 8,000 Da, or even from 4,000 to 7,000 Da. 
     The number-average molecular weight may be measured by any suitable method. Techniques to measure the number-average molecular weight will be well known to a person skilled in the art. Suitably, and as reported herein, the Mn may be determined by gel permeation chromatography using a polystyrene standard according to ASTM D6579-11(“Standard Practice for Molecular Weight Averages and Molecular Weight Distribution of Hydrocarbon, Rosin and Terpene Resins by Size Exclusion Chromatography”. UV detector; 254 nm, solvent: unstabilised THF, retention time marker: toluene, sample concentration: 2 mg/ml). 
     The polyester material, the acrylic polyester resin and/or a coating formed from the coating composition may have any suitable glass transition temperature (Tg). The polyester material, the acrylic polyester resin and/or a coating formed from the coating composition may have a Tg from 25° C. to 200° C. 
     The polyester material, the acrylic polyester resin and/or a coating formed from the coating composition may have a Tg of at least 25°, or at least 30° C., or at least 35° C., such as at least 40° C. or at least 45° C., or at least 50° C. such as at least 55° C. or at least 60° C., or at least 65° C., or at least 70° C., or at least 75° C., or at least 80° C. 
     The polyester material, the acrylic polyester resin and/or a coating formed from the coating composition may have a Tg of up to 200° C. such as up to 150° C., or up to 120° C., or up to 110° C., or up to 105° C. 
     The Tgs mentioned herein are measured according to ASTM D6604-00(2013) (“Standard Practice for Glass Transition Temperatures of Hydrocarbon Resins by Differential Scanning calorimetry” unless otherwise indicated. Heat-flux differential scanning calorimetry (DSC), sample pans: aluminium, reference: blank, calibration: indium and mercury, sample weight: 10 mg, heating rate: 20° C./min). 
     The polyester material may have any suitable gross hydroxyl value (OHV). The polyester material may have a gross OHV from 0 to 120 mg KOH/g. 
     The gross OHV, is suitably expressed on solids. 
     The gross hydroxyl value (OHV) of the polyester material may be measured by any suitable method. Methods to measure OHV will be well known to a person skilled in the art. Suitably, and as reported herein, the hydroxyl value is the number of mg of KOH equivalent to the hydroxyl groups in 1 g of material. In such a method, suitably, a sample of solid polyester (0.13 g) is weighed accurately into a conical flask and is dissolved, using light heating and stirring as appropriate, in 20 ml of tetrahydrofuran. 10 ml of 0.1 M 4-(dimethylamino)pyridine in tetrahydrofuran (catalyst solution) and 5 ml of a 9 vol % solution of acetic anhydride in tetrahydrofuran (i.e. 90 ml acetic anhydride in 910 ml tetrahydrofuran; acetylating solution) are then added to the mixture. After 5 minutes, 10 ml of an 80 vol % solution of tetrahydrofuran (i.e. 4 volume parts tetrahydrofuran to 1 part distilled water; hydrolysis solution) is added. After 15 minutes, 10 ml tetrahydrofuran is added and the solution is titrated with 0.5M ethanolic potassium hydroxide (KOH). A blank sample is also run where the sample of solid polyester is omitted. The resulting hydroxyl number is expressed in units of mg KOH/g and is calculated using the following equation: 
     
       
         
           
             
               Hydroxyl 
                
               
                   
               
                
               value 
             
             = 
             
               
                 
                   ( 
                   
                     
                       V 
                       2 
                     
                     - 
                     
                       V 
                       1 
                     
                   
                   ) 
                 
                 × 
                 molarity 
                  
                 
                     
                 
                  
                 of 
                  
                 
                     
                 
                  
                 KOH 
                  
                 
                     
                 
                  
                 solution 
                  
                 
                     
                 
                  
                 
                   ( 
                   M 
                   ) 
                 
                 × 
                 56.1 
               
               
                 weight 
                  
                 
                     
                 
                  
                 of 
                  
                 
                     
                 
                  
                 solid 
                  
                 
                     
                 
                  
                 sample 
                  
                 
                     
                 
                  
                 
                   ( 
                   g 
                   ) 
                 
               
             
           
         
       
     
     wherein V 1  is the titre of KOH solution (ml) of the polyester sample and V 2  is the titre of KOH solution (ml) of the blank sample. All values for gross hydroxyl value reported herein were measured in this way. 
     The polyester material may have any suitable acid value (AV). The polyester material may have an AV from 0 to 20 KOH/g. Suitably, the polyester may have a gross AV from 0 to 10 mg KOH/g, suitably less than 5 or even less than 3. 
     The AV is suitably expressed on solids. 
     The acid value (AV) of the polyester material may be measured by any suitable method. Methods to measure AN will be well known to a person skilled in the art. Suitably, and as reported herein, the AN is determined by titration with 0.1M methanolic potassium hydroxide (KOH) solution. In such a method, a sample of solid polyester (0.1 g) is weighed accurately into a conical flask and is dissolved, using light heating and stirring as appropriate, in 25 ml of dimethyl formamide containing phenolphthalein indicator. The solution is then cooled to room temperature and titrated with the 0.1 M methanolic potassium hydroxide solution. The resulting acid number is expressed in units of mg KOH/g and is calculated using the following equation: 
     
       
         
           
             
               Acid 
                
               
                   
               
                
               number 
             
             = 
             
               
                 
                   
                     
                       titre 
                        
                       
                           
                       
                        
                       of 
                        
                       
                           
                       
                        
                       KOH 
                        
                       
                           
                       
                        
                       solution 
                        
                       
                           
                       
                        
                       
                         ( 
                         ml 
                         ) 
                       
                       × 
                     
                   
                 
                 
                   
                     
                       molarity 
                        
                       
                           
                       
                        
                       KOH 
                        
                       
                           
                       
                        
                       solution 
                        
                       
                           
                       
                        
                       
                         ( 
                         M 
                         ) 
                       
                       × 
                       56.1 
                     
                   
                 
               
               
                 weight 
                  
                 
                     
                 
                  
                 of 
                  
                 
                     
                 
                  
                 solid 
                  
                 
                     
                 
                  
                 sample 
                  
                 
                     
                 
                  
                 
                   ( 
                   g 
                   ) 
                 
               
             
           
         
       
     
     All values for acid number reported herein were measured in this way. 
     The acrylic polyester resin, which may be an acrylic modified polyester resin may be present in the aqueous coating composition or powder coating composition in an amount of from 50 to 99 wt % (based on dry weight of the coating composition). Suitably, the acrylic polyester resin, which may be an acrylic modified polyester resin, may be present in the aqueous coating composition or powder coating composition in an amount of from 60 to 95 wt % (based on dry weight of the coating composition). 
     The acrylic polyester resin, which may be an acrylic modified polyester resin, may have any suitable number-average molecular weight (Mn). The acrylic polyester resin, which may be an acrylic modified polyester resin, may have an Mn from 1,000 Daltons (Da=g/mole) to 15,000 Da, suitably from 2,000 Da to 10,000 Da, such as from 3,000 Da to 8,000 Da, or even from 4,000 to 7,000 Da. 
     The number-average molecular weight may be measured by any suitable method. Techniques to measure the number-average molecular weight will be well known to a person skilled in the art. Suitably, and as reported herein, the Mn may be determined by gel permeation chromatography using a polystyrene standard according to ASTM D6579-11(“Standard Practice for Molecular Weight Averages and Molecular Weight Distribution of Hydrocarbon, Rosin and Terpene Resins by Size Exclusion Chromatography”. UV detector; 254 nm, solvent: unstabilised THF, retention time marker: toluene, sample concentration: 2 mg/ml). 
     The Tg of the acrylic modification polymer (which is a measure of the Tg of the acrylic modification polymer, polymerized as a simple acrylic polymer, not in the presence of (or grafted onto) a polyester material) may be from 20 to 120° C. The Tg of the acrylic modification polymer can be calculated by the Fox equation as provided in “Coatings of Polymers and Plastics”, Ryntz R. A. and Yaneff P. V, CRC Press, 4 Feb. 2003, page 134. 
     The acrylic polyester resin, which may be an acrylic modified polyester resin, may have any suitable gross hydroxyl value (OHV). The acrylic modified polyester resin may have a gross OHV from 0 to 120 mg KOH/g. 
     The gross OHV is suitably expressed on solids. 
     The acrylic polyester resin, which may be an acrylic modified polyester resin, may have any suitable acid value (AV). The acrylic modified polyester resin may have an AV from 10 to 80 KOH/g. Suitably, the acrylic modified polyester resin may have a gross AV from 20 to 70 mg KOH/g, such as from 30 to 60 mg KOH/g. 
     The AV is suitably expressed on solids. 
     Suitably, the acrylic polyester resin, which may be an acrylic modified polyester resin, is formed from the polyester material and the acrylic modification polymer in a weight ratio of from 85 wt % to 55 wt % polyester material to from 45 wt % to 15 wt % acrylic modification polymer, such as a weight ratio of from 80 wt % to 60 wt % polyester material to from 40 wt % to 20 wt % acrylic modification polymer, such as a weight ratio of from 75 wt % to 65 wt % polyester material to from 35 wt % to 25 wt % acrylic modification polymer. For example, the acrylic modified polyester resin may be formed from the polyester material and the acrylic modification polymer in a weight ratio of 70 wt % polyester material to 30 wt % acrylic modification polymer. 
     The acrylic polyester resin, which may be an acrylic modified polyester resin, may be present in the aqueous coating composition or powder coating composition in an amount of from 50 to 99 wt % (based on dry weight of the coating composition). Suitably, the acrylic polyester resin may be present in the aqueous coating composition or powder coating composition in an amount of from 60 to 95 wt % (based on dry weight of the coating composition). 
     The polyester material according to the present invention may be prepared in the presence of an esterification catalyst. Suitably, the esterification catalyst may be chosen to promote the reaction of components by esterification and/or trans-esterification. Suitable examples of esterification catalysts for use in the preparation of the polyester material include, but are not limited to the following: metal compounds such as stannous octoate; stannous chloride; butyl stannoic acid (hydroxy butyl tin oxide); monobutyl tin tris (2-ethylhexanoate); chloro butyl tin dihydroxide; dibutyl tin oxide; tetra-n-propyl titanate; tetra-n-butyl titanate; zinc acetate; acid compounds such as phosphoric acid; para-toluene sulphonic acid; dodecyl benzene sulphonic acid (DDBSA), tetra alkyl zirconium materials, antimony trioxide, germanium dioxide, bismuth octoate and combinations thereof. The esterification catalyst may be dodecyl benzene sulphonic acid (DDBSA). The esterification catalyst may be dibutyl tin oxide. 
     The esterification catalyst, when present, may be used in amounts from 0.001 to 1% by weight on total polymer components, suitably from 0.01 to 0.2%, such as from 0.025 to 0.2% by weight on total polymer components. 
     The term “aliphatic” herein means a hydrocarbon moiety that may be straight chain or branched and may be completely saturated, or contain a unit of unsaturation, but which is not aromatic. The term “unsaturated” means a moiety that has a double and/or triple bond. The term “aliphatic” is therefore intended to encompass alkyl, alkenyl or alkynyl groups. An aliphatic group may be interrupted by a heteroatom. Suitably, the heteroatom is nitrogen, oxygen and/or sulphur. 
     “Aliphatic” herein includes alicyclic group which is a saturated or partially unsaturated cyclic aliphatic monocyclic or polycyclic (including fused, bridging and spiro-fused) ring system which has from 3 to 20 carbon atoms, that is an alicyclic group with 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 carbon atoms. An alicyclic group may comprise from 3 to 15, such as from 3 to 12, or from 3 to 10, or from 3 to 8 carbon atoms, for example from 3 to 6 carbons atoms. The term “alicyclic” encompasses cycloalkyl, cycloalkenyl and cycloalkynyl groups. It will be appreciated that the alicyclic group may comprise an alicyclic ring bearing a linking or non-linking alkyl substituent, such as —CH 2 -cyclohexyl. Specifically, examples of the C 3-20  cycloalkyl group include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, adamantly, isobornyl and cyclooctyl. 
     The term “alk” or “alkyl”, as used herein unless otherwise defined, relates to saturated hydrocarbon radicals being straight, branched, cyclic or polycyclic moieties or combinations thereof and contain 1 to 20 carbon atoms, suitably 1 to 10 carbon atoms, more suitably 1 to 8 carbon atoms, still more suitably 1 to 6 carbon atoms, yet more suitably 1 to 4 carbon atoms. These radicals may be optionally substituted with a chloro, bromo, iodo, cyano, nitro, OR 19 , OC(O)R 20 , C(O)R 21 , C(O)OR 22 , NR 23 R 24 , C(O)NR 25 R 26 , SR 27 , C(O)SR 27 , C(S)NR 25 R 26 , aryl or heteroatom, wherein R 19  to R 27  each independently represent hydrogen, aryl or alkyl, and/or be interrupted by oxygen or sulphur atoms, or by silano or dialkylsiloxane groups. Examples of such radicals may independently be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, pentyl, iso-amyl, hexyl, cyclohexyl, 3-methylpentyl, octyl and the like. The term “alkylene”, as used herein, relates to a bivalent radical alkyl group as defined above. For example, an alkyl group such as methyl which would be represented as —CH 3 , becomes methylene, —CH 2 —, when represented as an alkylene. Other alkylene groups should be understood accordingly. 
     The term “alkenyl”, as used herein, relates to hydrocarbon radicals having a double bond, suitably up to 4, double bonds, being straight, branched, cyclic or polycyclic moieties or combinations thereof and containing from 2 to 18 carbon atoms, suitably 2 to 10 carbon atoms, more suitably from 2 to 8 carbon atoms, still more suitably 2 to 6 carbon atoms, yet more suitably 2 to 4 carbon atoms. These radicals may be optionally substituted with a hydroxyl, chloro, bromo, iodo, cyano, nitro, OR 19 , OC(O)R 20 , C(O)R 21 , C(O)OR 22 , NR 23 R 24 , C(O)NR 25 R 26 , SR 27 , C(O)SR 27 , C(S)NR 25 R 26 , or aryl, wherein R 19  to R 27  each independently represent hydrogen, aryl or alkyl, and/or be interrupted by oxygen or sulphur atoms, or by silano or dialkylsiloxane groups. Examples of such radicals may independently be alkenyl groups include vinyl, allyl, isopropenyl, pentenyl, hexenyl, heptenyl, cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, 1-propenyl, 2-butenyl, 2-methyl-2-butenyl, isoprenyl, farnesyl, geranyl, geranylgeranyl and the like. The term “alkenylene”, as used herein, relates to a bivalent radical alkenyl group as defined above. For example, an alkenyl group such as ethenyl which would be represented as —CH═CH 2 , becomes ethenylene, —CH═CH—, when represented as an alkenylene. Other alkenylene groups should be understood accordingly. 
     The term “alkynyl”, as used herein, relates to hydrocarbon radicals having a triple bond, suitably up to 4, triple bonds, being straight, branched, cyclic or polycyclic moieties or combinations thereof and having from 2 to 18 carbon atoms, suitably 2 to 10 carbon atoms, more suitably from 2 to 8 carbon atoms, still more suitably from 2 to 6 carbon atoms, yet more suitably 2 to 4 carbon atoms. These radicals may be optionally substituted with a hydroxy, chloro, bromo, iodo, cyano, nitro, OR 19 , OC(O)R 20 , C(O)R 21 , C(O)OR 22 , NR 23 R 24 , C(O)NR 25 R 26 , SR 27 , C(O)SR 27 , C(S)NR 25 R 26 , or aryl, wherein R 19  to R 27  each independently represent hydrogen, aryl or lower alkyl, and/or be interrupted by oxygen or sulphur atoms, or by silano or dialkylsiloxane groups. Examples of such radicals may independently be alkynyl radicals include ethynyl, propynyl, propargyl, butynyl, pentynyl, hexynyl and the like. The term “alkynylene”, as used herein, relates to a bivalent radical alkynyl group as defined above. For example, an alkynyl group such as ethynyl which would be represented as —C≡CH, becomes ethynylene, —C≡C—, when represented as an alkynylene. Other alkynylene groups should be understood accordingly. 
     The term “aryl” as used herein, relates to an organic radical derived from an aromatic hydrocarbon by removal of one hydrogen, and includes any monocyclic, bicyclic or polycyclic carbon ring of up to 7 members in each ring, wherein at least one ring is aromatic. These radicals may be optionally substituted with a hydroxy, chloro, bromo, iodo, cyano, nitro, OR 19 , OC(O)R 20 , C(O)R 21 , C(O)OR 22 , NR 23 R 24 , C(O)NR 25 R 26 , SR 27 , C(O)SR 27 , C(S)NR 26 R 26 , or aryl, wherein R 19  to R 27  each independently represent hydrogen, aryl or lower alkyl, and/or be interrupted by oxygen or sulphur atoms, or by silano or dialkylsilcon groups. Examples of such radicals may independently be from phenyl, p-tolyl, 4-methoxyphenyl, 4-(tert-butoxy)phenyl, 3-methyl-4-methoxyphenyl, 4-fluorophenyl, 4-chlorophenyl, 3-nitrophenyl, 3-aminophenyl, 3-acetamidophenyl, 4-acetamidophenyl, 2-methyl-3-acetamidophenyl, 2-methyl-3-aminophenyl, 3-methyl-4-aminophenyl, 2-amino-3-methylphenyl, 2,4-dimethyl-3-aminophenyl, 4-hydroxyphenyl, 3-methyl-4-hydroxyphenyl, 1-naphthyl, 2-naphthyl, 3-amino-1-naphthyl, 2-methyl-3-amino-1-naphthyl, 6-amino-2-naphthyl, 4,6-dimethoxy-2-naphthyl, tetrahydronaphthyl, indanyl, biphenyl, phenanthryl, anthryl or acenaphthyl and the like. The term “arylene”, as used herein, relates to a bivalent radical aryl group as defined above. For example, an aryl group such as phenyl which would be represented as -Ph, becomes phenylene, -Ph-, when represented as an arylene. Other arylene groups should be understood accordingly. 
     For the avoidance of doubt, the reference to alkyl, alkenyl, alkynyl, aryl or aralkyl in composite groups herein should be interpreted accordingly, for example the reference to alkyl in aminoalkyl or alk in alkoxyl should be interpreted as alk or alkyl above etc. 
     The aqueous coating composition or powder coating composition of the present invention comprise a crosslinking material. The crosslinking material may be operable to crosslink the acrylic modified polyester resin. The crosslinking material may be a single molecule, a dimer, an oligomer, a (co)polymer or a mixture thereof. The crosslinking material may be a dimer or trimer. 
     The crosslinking material may be operable to crosslink the acrylic polyester resin. 
     The crosslinking material may comprise any suitable crosslinking material. Suitable crosslinking materials will be well known to the person skilled in the art. Suitable crosslinking materials include, but are not limited to the following: benzoguanamine, phenolic resins (or phenol-formaldehyde resins); aminoplast resins (or triazine-formaldehyde resins); amino resins; epoxy resins; isocyanate resins; beta-hydroxy (alkyl) amide resins; alkylated carbamate resins; polyacids; anhydrides; organometallic acid-functional materials; polyamines; polyamides and combinations thereof. 
     Suitable crosslinking materials include, but are not limited to the following: melamine, benzoguanamine, phenolic resins (or phenol-formaldehyde resins); aminoplast resins (or triazine-formaldehyde resins); amino resins; epoxy resins; isocyanate resins; beta-hydroxy (alkyl) amide resins; alkylated carbamate resins; polyacids; anhydrides; organometallic acid-functional materials; polyamines; polyamides and combinations thereof. 
     Non-limiting examples of phenolic resins are those formed from the reaction of a phenol with an aldehyde or a ketone, suitably from the reaction of a phenol with an aldehyde, such as from the reaction of a phenol with formaldehyde or acetaldehyde, or even from the reaction of a phenol with formaldehyde. Non-limiting examples of phenols which may be used to form phenolic resins are phenol, butyl phenol, xylenol and cresol. General preparation of phenolic resins is described in “The Chemistry and Application of Phenolic Resins or Phenoplasts”, Vol V, Part I, edited by Dr Oldring; John Wiley and Sons/Cita Technology Limited, London, 1997. Suitably, the phenolic resins are of the resol type. By “resol type” we mean resins formed in the presence of a basic (alkaline) catalyst and optionally an excess of formaldehyde. Suitable examples of commercially available phenolic resins include, but are not limited to those sold under the trade name PHENODUR (RTM) commercially available from Cytec Industries, such as PHENODUR EK-827, PHENODUR VPR1785, PHENODUR PR 515, PHENODUR PR516, PHENODUR PR 517, PHENODUR PR 285, PHENODUR PR612 or PHENODUR PH2024; resins sold under the trade name BAKELITE (RTM) commercially available from Momentive, such as BAKELITE 6582 LB, BAKELITE 6535, BAKELITE PF9989 or BAKELITE PF6581; SFC 112 commercially available from Schenectady; DUREZ (RTM) 33356 commercially available from SHHPP; ARALINK (RTM) 40-852 commercially available from Bitrez; or combinations thereof. 
     The aqueous coating composition or powder coating composition may be substantially formaldehyde free, or suitably essentially formaldehyde free, or suitably completely formaldehyde free. By “substantially free” we mean to refer to aqueous coating compositions or powder coating composition containing less than 1000 parts per million (ppm) of any of the compounds or derivatives thereof mentioned above. By “essentially free” we mean to refer to aqueous coating compositions containing or powder coating composition less than 100 ppm of any of the compounds or derivatives thereof mentioned above. By “completely free” we mean to refer to aqueous coating compositions or powder coating composition containing less than 20 parts per billion (ppb) of any of the compounds or derivatives thereof. 
     Non limiting examples of isocyanate resins include, but are not limited to the following: isophorone diisocyanate (IPDI), such as those sold under the trade name DESMODUR (RTM) commercially available from Bayer, for example DESMODUR VP-LS 2078/2 or DESMODUR PL 340 or those sold under the trade name VESTANAT (RTM) commercially available from Evonik, for example VESTANANT B 1370, VESTANAT B 118 6A or VESTANAT B 1358 A; blocked aliphatic polyisocyanate based on hexamethylene diisocyanate (HDI), such as those sold under the trade name DESMODUR (RTM) commercially available from Bayer, for example DESMODUR BL3370 or DESMODUR BL 3175 SN, those sold under the trade name DURANATE (RTM) commercially available from Asahi KASEI, for example DURANATE MF-K60X, those sold under the trade name TOLONATE (RTM) commercially available from Perstorp, for example TOLONATE D2 or those sold under the trade name TRIXENE (RTM) commercially available from Baxenden, for example TRIXENE-BI-7984 or TRIXENE 7981; or combinations thereof. 
     The crosslinking material may contain nitrogen. The crosslinking material may be in the form of an amine or amide material. The crosslinking material may comprise a hydroxyl substituted amine or amide material. 
     Suitably, the crosslinking material may comprise a hydroxyalkylamide material, such as a β-hydroxyalkylamide material. 
     The crosslinking material may contain a terminal chemical group as shown in Formula I. 
     
       
         
         
             
             
         
       
     
     wherein R 10  represents an electron withdrawing group, such as (═O); and
 
Y 1  and Y 2  each, independently, represents a C 1  to C 3  alkylene group.
 
     The terminal chemical group of Formula I may be connected to a further chemical structure, not shown. Additionally or alternatively, the chemical group of formula I may be suspended from a carrier substrate, such as a silica carrier substrate, for example. 
     The crosslinking material may contain a plurality of terminal chemical groups as shown in Formula I. For example, the crosslinking material may contain 2, 3 or 4 terminal chemical groups as shown in Formula I. 
     The crosslinking material may comprise a moiety according to Formula II: 
     
       
         
         
             
             
         
       
     
     wherein R 10  and R 11  each, independently, represent an electron withdrawing group, such as (═O);
 
Y 1 , Y 2 , Y 3  and Y 4  each, independently, represent a C 1  to C 3  alkylene group; and
 
X represents a C 2  to C 6  alkylene group.
 
     Suitably, each of R 10  and R 11  represents a (═O) group. 
     Suitably, each of Y 1 , Y 2 , Y 3  and Y 4  represent an ethylene group. 
     Suitably, X represents a butylene group. 
     Accordingly, the crosslinking material may comprise a material of formula III: 
     
       
         
         
             
             
         
       
     
     The crosslinking material may comprise a commercially available β-hydroxyalkylamide crosslinking, such as, for example, PRIMID XL-552 (available from Rohm and Haas); PRIMID QM-1260 (available from EMS Chemie); and N,N,N′,N′-tetrakis(2-hydroxypropyl)adipamide. 
     The crosslinking material may be in the form of a urea material. The crosslinking material may comprise a hydroxyl substituted urea material. 
     Suitably, the crosslinking material may comprise a hydroxy functional alkyl polyurea material. 
     The crosslinking material may contain a terminal chemical group as shown in Formula IV. 
     
       
         
         
             
             
         
       
     
     wherein Y 5  and Y 6  each, independently, represent hydrogen, an alkyl or a hydroxy functional alkyl having two or more carbon atoms and at least one of Y 5  and Y 6  is a hydroxyl functional alkyl having two or more carbon atoms. 
     The Y 5  and Y 6  groups may exclude ether linkages. 
     The terminal chemical group of Formula IV may be connected to a further chemical structure, not shown. Additionally or alternatively, the chemical group of Formula IV may be suspended from a carrier substrate, such as a silica carrier substrate, for example. 
     The crosslinking material may contain a plurality of terminal chemical groups as shown in Formula IV. For example, the crosslinking material may contain 2 to 6 terminal chemical groups as shown in Formula IV, such as 2, 3 or 4 terminal chemical groups as shown in Formula IV. 
     The crosslinking material may comprise a moiety according to Formula V: 
     
       
         
         
             
             
         
       
     
     wherein R comprises the residue of an isocyanurate, biuret, allophonate, glycoluril, benzoguanamine, and/or polyetheramine;
 
each R 1  is independently a hydrogen, an alkyl or a hydroxy functional alkyl having 2 or more carbons and at least one R 1  is a hydroxy functional alkyl having 2 or more carbons;
 
and n is 2-6.
 
     Suitably, the R 1  group may exclude ether linkages. 
     The crosslinking material may comprise a moiety according to Formula VI: 
     
       
         
         
             
             
         
       
     
     wherein R 2  comprises a substituted or unsubstituted C 1  to C 36  alkyl group, an aromatic group, or the residue of an isocyanurate, biuret, allophonate, glycoluril, benzoguanamine, and/or polyetheramine;
 
each R 1  is independently a hydrogen, an alkyl group having 1 or more carbons, or a hydroxy functional alkyl having 2 or more carbons and at least one R 1  is a hydroxy functional alkyl having 2 or more carbons;
 
and n is 2-6.
 
     Suitably, the R 1  group may exclude ether linkages. 
     R and R 2  may comprise the residue of an isocyanurate, biuret, allophonate, glycoluril, benzoguanamine and/or polyetheramine. An isocyanurate will be understood as referring to a compound having three isocyanate groups, typically in ring form, and is sometimes referred to as a trimer. This can include compounds having an isocyanurate moietie. Isocyanurates can be purchased from Covestro and Vencore X Chemical. Suitable commercially available isocyanurates include those sold under the trade name DESMODUR such as, for example, DESMODUR N 3300A, DESMODUR N3800, DESMODUR N3400, DESMODUR N3600, DESMODUR N3900 and DESMODUR RC (commercially available from Covestro), those sold under the trade name VESTANANT such as, for example, VESTANAT T1890/100 (commercially available from Evonik) and those sold under the trade name EASAQUA such as, for example, EASAQUA WT 2102, EASAQUA X D 401, EASAQUA M 501, EASAQUA X D 803, EASAQUA M 502 and EASAQUA X L 600 (commercially available from Vencore X Chemical). A suitable hydroxy functional alkyl polyurea may be formed from an isocyanurate is shown in Formula VII: 
     
       
         
         
             
             
         
       
     
     wherein R 1  is as described above;
 
and each R 3  independently comprises an alkyl, aryl, alkylaryl, arylalkyl, alicyclic, and/or polyetheralkyl group.
 
     A suitable hydroxy functional alkyl polyuria may be formed from a bis-isocyanurate is shown below in Formula VIII: 
     
       
         
         
             
             
         
       
     
     wherein R 1  and R 3  are as described above. 
     A biuret will be understood as referring to a compound that results upon the condensation of two molecules of urea, and is sometimes referred to as a carbamylurea. Biurets are commercial available from Vencore X Chemical and Covestro as, for example, DESMODUR N-75, DESMODUR N-100, and DESMODUR N-3200, HDB 75B, HDB 75M, HDB 75MX, HDB-LV. A suitable hydroxy functional alkyl polyurea may be formed from a biuret is shown below in Formula IX: 
     
       
         
         
             
             
         
       
     
     wherein R 1  is as described above;
 
each R 5  independently comprises an alkyl, aryl, alkylaryl, arylalkyl, alicyclic, and/or polyetheralkyl group; and R 6  comprises H or an alkyl group.
 
     Uretidione is a dimer of diisocyanate, examples of which include DESMODUR N-3400 polyisocyanate, a blend of the trimer and uretidione of HDI: 
     
       
         
         
             
             
         
       
     
     wherein each R 5  independently comprises an alkyl, aryl, alkylaryl, arylalkyl, alicyclic, and/or polyetheralkyl group. 
     An allophonate will be understood as referring to a compound made from urethane and isocyanate. A method for making an allophonate is described at Surface Coating, Vol 1, Raw material and their usage, Landon New York, Chapman and Hall, Page 106. The reaction is generally depicted below in scheme I: 
     
       
         
         
             
             
         
       
     
     wherein R 5  and R 6  are each as described above; and
 
R 7  independently comprises residues of a primary alcohol which is reacted with isocyanate.
 
     A glycoluril will be understood as referring to a compound composed of two cyclic urea groups joined across the same two-carbon chain, a suitable examples of which includes the below: 
     
       
         
         
             
             
         
       
     
     Glycoluril is widely commercially available, such as from Sigma-Aldrich. 
     Benzoguanamine is also known as 6-phenyl-1,3,5-triazine-2,4-diamine and is commercially available from The Chemical Company, Jamestown, R.I. 
     A polyether amine will be understood as referring to a compound having an amine group attached to a polyether backbone such as one characterized by propylene oxide, ethylene oxide, or mixed propylene oxide and ethylene oxide repeating units in their respective structures, such as, for example, one of the Jeffamine series products. Examples of such polyetheramines include aminated propoxylated pentaerythritols, such as JEFFAMINE XTJ-616, and those represented by Formulas (X) through (VI). 
     According to Formula (IV) the polyether amine may comprise: 
     
       
         
         
             
             
         
       
     
     wherein y=0-39, x+z=1-68. 
     Suitable amine-containing compounds represented by Formula X include, but are not limited to, amine-terminated polyethylene glycol such as those commercially available from Huntsman Corporation in its JEFFAMINE ED series, such as JEFFAMINE HK-511, JEFFAMINE ED-600, JEFFAMINE ED-900 and JEFFAMINE ED-2003, and amine-terminated polypropylene glycol such as in its JEFFAMINE D series, such as JEFFAMINE D-230, JEFFAMINE D-400, JEFFAMINE D-2000 and JEFFAMINE D-4000. 
     According to Formula XI the polyetheramine may comprise: 
     
       
         
         
             
             
         
       
     
     wherein each p independently is 2 or 3. 
     Suitable amine-containing compounds represented by Formula XI include, but are not limited to, amine-terminated polyethylene glycol based diamines, such as Huntsman Corporation&#39;s JEFFAMINE EDR series, such as JEFFAMINE EDR-148 and JEFFAMINE EDR-176. 
     According to Formula XII the polyetheramine may comprise: 
     
       
         
         
             
             
         
       
     
     wherein R 8  is H or C 2 H 5 , m=0 or 1, a+b+c=5-85. 
     Suitable amine-containing compounds represented by Formula (VI) include, but are not limited to, amine-terminated propoxylated trimethylolpropane or glycerol, such as Huntsman Corporation&#39;s Jeffamine T series, such as JEFFAMINE T-403, JEFFAMINE T-3000 and JEFFAMINE T-5000. 
     Suitable are di- and tri-amines, such as 4,7,10-trioxa-1,13-tridecanediamine, JEFFAMINE D400, JEFFAMINE D4000, JEFFAMINE D2000, JEFFAMINE T403. 
     In all cases, R 2  may be substituted or unsubstituted. R 2 , as noted above, may also comprise a substituted or unsubstituted C 1  to C 36  alkyl group and/or an aromatic group. For example, the alkyl group may have two to ten carbon atoms such as six carbon atoms. The alkyl group may derive from an isocyanate, such as a diisocyanate. Suitable examples include isophorone diisocyanate and hexamethylene isocyanate. The aromatic group may derive from an aromatic ring containing isocyanate, suitable examples of which include methylene diphenyl diisocyanate, toluene diisocyanate and tetramethylxylylene diisocyanate. 
     Certain hydroxy functional alkyl polyureas of, and/or used according to, the invention may be made by reacting an isocyanate-containing compound with amino alcohol. Any isocyanate-containing compound having at least two isocyanate groups can be used, such as any of those described above. It will be appreciated that the “R” or “R 2 ” group will reflect the isocyanate-containing compound selected. 
     Similarly, any amino alcohol having two or more carbon atoms can be used, and the “R 1 ” group will reflect the amino alcohol selected. The amino alcohol can have one, two or more hydroxyl functional groups. An amino alcohol can be used, which will result in different R 1  groups being present on the polyurea. R 1  can also be hydrogen or an alkyl group. Suitable amino alcohols include monoethanol amine, diethanol amine and diispropyl amine. 
     The hydroxyl functional alkyl polyureas can be made by reacting amino alcohol with an isocyanate-containing compound in an organic polar solvent, such as alcohol or water. The reaction temperate may be kept below 35° C. The equivalent ratio of amine to isocyanate may be 2-1:1-2, such as 1:1. 
     The hydroxy functional alkyl polyureas of, and/or used according to, the invention may be made by alternative methods as well. For example, amino alcohols can react with carbonate to form hydroxylalkyl carbamate, and hydroxylalkyl carbamate can further react with amines to form hydroxy functional alkyl polyureas. 
     The number-average molecular weight (Mn) of the hydroxy functional alkyl polyurea may be 100 or greater, such as 350 or greater or 1,000 or greater, and/or can be 6,000 or lower, such as 3,000 or lower, or 2,000 or lower. Mn means the theoretical value as determined by Gel Permeation Chromatography using Waters 2695 separation module with a Waters 410 differential refractometer (RI detector) and polystyrene standards. The range of molecular weights of the polystyrene standards for this method is from approximately 800 to 900,000 g/mol. In determining Mn according to the invention, tetrahydrofuran (THF) was used as the eluent at a flow rate of 1 ml min-1, and two PL Gel Mixed C columns were used for separation. 
     The hydroxyl functional alkyl polyurea material may be made by reacting a dialkanol amine with hexamethylene diisocyanate (HDI) trimer and/or isophorone diisocyanate (IDPI) trimer, suitably hexamethylene diisocyanate (HDI) trimer. The hydroxyl functional alkyl polyurea material may be made by reacting diethanolamine with hexamethylene diisocyanate (HDI) trimer and/or isophorone diisocyanate (IDPI) trimer, suitably hexamethylene diisocyanate (HDI) trimer. The hydroxyl functional alkyl polyurea material may be made by reacting diisopropanolamine with hexamethylene diisocyanate (HDI) trimer and/or isophorone diisocyanate (IDPI) trimer, suitably hexamethylene diisocyanate (HDI) trimer. 
     The crosslinking material may comprise material according to formula (XIII) 
     
       
         
         
             
             
         
       
     
     wherein R 1  is hydrogen, alkyl (such as C 1  to C 20  alkyl), aryl (such as C 4  to C 24  aryl), aralkyl (such as C 5  to C 25  aralkyl), or —NR 6 R 7 ;
 
R 2  to R 7  are each independently hydrogen, alkyl (such as C 1  to C 20  alkyl), aryl (such as C 4  to C 24  aryl), aralkyl (such as C 5  to C 25  aralkyl) or —CHR 8 OR 9 ;
 
wherein R 8  and R 9  are each independently hydrogen, alkyl (such as C 1  to C 20  alkyl), aryl (such as C 4  to C 24  aryl), aralkyl (such as C 5  to C 25  aralkyl), alkoxyalkyl (such as C 2  to C 40  alkoxyalkyl) or an alkaryl (such as C 5  to C 25  alkaryl);
 
wherein at least one of R 2  to R 5 , or R 2  to R 7  when present, is —CHR 8 OR 9 , suitably all of R 2  to R 5 , or R 2  to R 7  when present, are —CHR 8 OR 9 .
 
     Suitably, in the crosslinking material according to formula (XIII), R 1  is C 1  to C 20  alkyl, C 4  to C 24  aryl, C 5  to C 25  aralkyl, or —NR 6 R 7 ; such as C 4  to C 24  aryl or C 5  to C 25  aralkyl, or C 4  to C 24  aryl, suitably C 4  to C 12  aryl, such as C 6  aryl. 
     In the crosslinking material according to formula (XIII), R 1  may be —NR 6 R 7 . 
     In the crosslinking material according to formula (XIII), R 2  to R 7 , when present as applicable, may each be independently hydrogen, C 1  to C 20  alkyl, C 4  to C 24  aryl or —CHR 8 OR 9 ; such as hydrogen, C 1  to C 20  alkyl or —CHR 8 OR 9 , such as hydrogen, C 1  to C 10  alkyl or —CHR 8 OR 9 ; such as C 1  to C 5  alkyl or —CHR 8 OR 9 , suitably —CHR 8 OR 9 . 
     In the crosslinking material according to formula (XIII), R 2  to R 7 , when present as applicable, may each be independently hydrogen, C 1  to C 20  alkyl, C 4  to C 24  aryl or —CHR 8 OR 9 ; such as hydrogen, C 1  to C 20  alkyl or —CHR 8 OR 9 , such as hydrogen, C 1  to C 10  alkyl or —CHR 8 OR 9 ; such as C 1  to C 5  alkyl or —CHR 8 OR 9 , suitably —CHR 8 OR 9 , and R 8  may be independently be hydrogen, C 1  to C 20  alkyl, C 4  to C 24  aryl, C 5  to C 25  aralkyl, alkoxyalkyl C 2  to C 40  alkoxyalkyl or C 5  to C 25  alkaryl, such as hydrogen, C 1  to C 20  alkyl, suitably hydrogen; and R 9  may be hydrogen, C 1  to C 20  alkyl, C 4  to C 24  aryl, C 5  to C 25  aralkyl, alkoxyalkyl C 2  to C 40  alkoxyalkyl or C 5  to C 25  alkaryl; such as hydrogen, C 1  to C 20  alkyl; suitably C 1  to C 20  alkyl, or C 1  to C 10  alkyl, or C 1  to C 5  alkyl, such as C 1  or C 2  alkyl. 
     The crosslinking material according to formula (XIII) may be formed by reacting a triazine such as melamine or benzoguanamine with formaldehyde. Suitably, these condensates may be etherified, typically, with methanol, ethanol, butanol or mixtures thereof. For the chemistry, preparation and use of aminoplast resins, see “The Chemistry and Applications of Amino Crosslinking agents or Aminoplast”, Vol. V, Part 11, page 21 ff., edited by Dr. Oldring; John Wiley &amp; Sons/Cita Technology Limited, London, 1998. 
     The crosslinking material according to formula (XIII) may comprise melamine or derivatives thereof, such as butylated and/or methylated melamine; and benzoguanamine or derivatives thereof, such as butylated and/or methylated benzoguanamine. Suitably, the crosslinking material according to formula (XIII) comprises benzoguanamine or derivatives thereof, such as butylated and/or methylated benzoguanamine. 
     The crosslinking material according to formula (XIII) may form at least 50 wt % of the crosslinking material of the coating composition, such as at least 60 wt %, at least 70 wt %, at least 80 wt %, at least 90 wt %, at least 95 wt % or at least 98 wt % such as at least 99 wt % of the crosslinking material of the coating composition. 
     The crosslinking material may be substantially formed of crosslinking material according to formula (XIII). 
     The crosslinking material may comprise a phenolic resin, benzoguanamine and/or melamine. Suitably, the crosslinking material comprises benzoguanamine. 
     The crosslinking material may be present in the aqueous coating composition or powder coating composition of the present invention is any suitable amount. The aqueous coating composition or powder coating composition may comprise from 0.5 to 40 wt %, suitably from 1 to 30 wt %, such as from 5 to 20 wt % of the crosslinking material based on the total solid weight of the coating composition. 
     The aqueous coating composition or powder coating composition may comprise a catalyst. Suitable examples of catalysts include, but are not limited to the following: metal compounds such as stannous octoate; stannous chloride; butyl stannoic acid (hydroxy butyl tin oxide); monobutyl tin tris (2-ethylhexanoate); chloro butyl tin dihydroxide; tetra-n-propyl titanate; tetra-n-butyl titanate; zinc acetate; acid compounds such as phosphoric acid; para-toluene sulphonic acid; dodecyl benzene sulphonic acid (DDBSA) such as blocked DDBSA, tetra alkyl zirconium materials, antimony trioxide, germanium dioxide and combinations thereof. The catalyst may comprise dodecyl benzene sulphonic acid (DDBSA), such as blocked DDBSA. 
     The catalyst may be present in the aqueous coating composition or powder coating composition in amounts from 0.001 to 1% by dry weight of the coating composition, suitably from 0.01 to 0.7%, such as from 0.025 to 0.5% by dry weight of the coating composition. 
     The aqueous coating composition or powder coating composition according to the present invention may be substantially free of bisphenol A (BPA) and derivatives thereof. The aqueous coating composition or powder coating composition according to the present invention may be essentially free or may be completely free of bisphenol A (BPA) and derivatives thereof. Derivatives of bisphenol A include, for example, bisphenol A diglycidyl ether (BADGE). 
     The aqueous coating composition or powder coating composition according to the present invention may be substantially free of bisphenol F (BPF) and derivatives thereof. The aqueous coating composition or powder coating composition according to the present invention may be essentially free or may be completely free of bisphenol F (BPF) and derivatives thereof. Derivatives of bisphenol F include, for example, bisphenol F diglycidyl ether (BPFG). 
     The aqueous coating composition or powder coating composition according to the present invention may be substantially free of styrene. The aqueous coating composition or powder coating composition according to the present invention may be essentially free or may be completely free of styrene. 
     The compounds or derivatives thereof mentioned above, i.e. BPA, BPF and derivatives thereof, may not be added to the composition intentionally but may be present in trace amounts because of unavoidable contamination from the environment. By “substantially free” we mean to refer to coating compositions containing less than 1000 parts per million (ppm) of any of the compounds or derivatives thereof mentioned above. By “essentially free” we mean to refer to coating compositions containing less than 100 ppm of any of the compounds or derivatives thereof mentioned above. By “completely free” we mean to refer to aqueous coating composition or powder coating composition containing less than 20 parts per billion (ppb) of any of the compounds or derivatives thereof. 
     The aqueous coating composition or powder coating composition may comprise an adhesion promoter. The adhesion promoter may comprise and acidic polyester. 
     The acidic polyester may be added in an amount of from 0.1 to 15 wt % (based on the dry weight of the coating composition ingredients), more suitably from 2 to 12 wt % (based on the dry weight of the coating composition ingredients). The acidic polyester may be present in an amount of from 4 to 10 wt % (based on the dry weight of the coating composition ingredients). 
     The acidic polyester may comprise a reaction product of a polyester with a phosphorus acid, such as phosphoric acid. In this context, the polyester may have an Mn of 2000 to 10,000. The polyester may have a hydroxyl number of 20 to 75. The polyester may have an acid value of 15 to 25. 
     Suitably, the acidic polyester comprises a solution of a copolymer with acidic groups having an acid value from 15 up to 100 mgKOH/g. Examples of commercially available suitable acidic polyesters include are BYK-4510 (commercially available from Byk Altana) or PLUSOLIT H-PD (commercially available from Mader) or BORCHI GEN HMP-F or BORCHI GEN HE (commercially available from OMG Borchers). 
     The acidic polyester may generally comprise the reaction product of: 
     (a) a polyester having an Mn of 2000 to 10,000, a hydroxyl number of 20 to 75, and an acid value of 15 to 25; the polyester being a polycondensate of: 
     (i) a polyol component comprising a mixture of diols and triols, 
     (ii) a polyacid component comprising an alpha, beta-ethylenically unsaturated polycarboxylic acid, 
     and
 
(b) a phosphorus acid.
 
     Further suitable examples of acidic polyesters are given in WO 2012/162301, the contents of which are entirely incorporated herein by reference. 
     The aqueous coating composition or powder coating composition of the present invention may comprise a further resin material. Suitable further resin materials will be well known to a person skilled in the art. Suitable examples of further resin materials include, but are not limited to the following: polyester resins; acrylic resins; polyvinyl chloride (PVC) resins; alkyd resins; polyurethane resins; polysiloxane resins; epoxy resins or combinations thereof. Suitably, the further resin material may comprise polyvinyl chloride (PVC) resins. 
     The aqueous coating composition or powder coating composition of the present invention may comprise other optional materials well known in the art of formulating coatings, such as colorants, plasticizers, abrasion-resistant particles, anti-oxidants, hindered amine light stabilizers, UV light absorbers and stabilizers, surfactants, flow control agents, thixotropic agents, fillers, organic co-solvents, reactive diluents, catalysts, grind vehicles, lubricants, waxes and other customary auxiliaries. It may be desired to use some quantity of non-polymerisable surfactant in conjunction with the polymerisable surfactant in the preparation of the latex and/or in a coating comprising the latex. 
     As used herein, the term “colorant” means any substance that imparts colour and/or other opacity and/or other visual effect to the composition. The colorant can be added to the aqueous coating composition or powder coating composition in any suitable form, such as discrete particles, dispersions, solutions and/or flakes. A single colorant or a mixture of two or more colorants can be used in the aqueous coating composition or powder coating composition of the present invention. Suitable colorants are listed in U.S. Pat. No. 8,614,286, column 7, line 2 through column 8, line 65, which is incorporated by reference herein. Suitable for packaging coatings are those approved for food contact, such as titanium dioxide; iron oxides, such as black iron oxide; aluminium paste; aluminium powder such as aluminium flake; carbon black; ultramarine blue; phthalocyanines, such as phthalocyanine blue and phthalocyanine green; chromium oxides, such as chromium green oxide; graphite fibrils; ferried yellow; quindo red; and combinations thereof, and those listed in Article 178.3297 of the Code of Federal Regulations, which is incorporated by reference herein. 
     The aqueous coating composition or powder coating composition may comprise aluminium paste, aluminium powder, such as aluminium flake, or a combination thereof. Suitably, the aqueous coating composition or powder coating composition may comprise aluminium paste. 
     The colorant, when present, may be used in the aqueous coating composition or powder coating composition in any suitable amount. The colorant, when present, may be used in the aqueous coating composition or powder coating composition in amounts up to 90 wt %, such as up to 50 wt %, or even up to 10 wt % based on the total solid weight of the coating composition. 
     Suitable lubricants will be well known to the person skilled in the art. Suitable examples of lubricants include, but are not limited to the following: carnuba wax, PTFE, polypropylene and polyethylene type lubricants. The lubricant, when present, may be used in the aqueous coating composition or powder coating composition in amounts of at least 0.01 wt % based on the total solid weight of the coating composition, suitably 0.5 to 2 wt %. 
     Surfactants may optionally be added to the aqueous coating composition or powder coating composition in order to aid in flow and wetting of the substrate. Suitable surfactants will be well known to the person skilled in the art. Suitably the surfactant, when present, is chosen to be compatible with food and/or beverage container applications. Suitable surfactants include, but are not limited to the following: alkyl sulphates (e.g., sodium lauryl sulphate); ether sulphates; phosphate esters; sulphonates; and their various alkali, ammonium, amine salts; aliphatic alcohol ethoxylates; alkyl phenol ethoxylates (e.g. nonyl phenol polyether); salts and/or combinations thereof. The surfactants, when present, may be present in amounts from 0.01 wt % to 10 wt %, suitably from 0.01 to 5 wt %, such as from 0.01 to 2 wt % based on the total solid weight of the coating composition. 
     The aqueous coating composition or powder coating composition of the present invention may be substantially free, may be essentially free or may be completely free of dialkyltin compounds, including oxides or other derivatives thereof. Examples of dialkyltin compounds include, but are not limited to the following: dibutyltindilaurate (DBTDL); dioctyltindilaurate; dimethyltin oxide; diethyltin oxide; dipropyltin oxide; dibutyltin oxide (DBTO); dioctyltinoxide (DOTO) or combinations thereof. By “substantially free” we mean to refer to coating compositions containing less than 1000 parts per million (ppm) of any of the compounds or derivatives thereof mentioned above. By “essentially free” we mean to refer to coating compositions containing less than 100 ppm of any of the compounds or derivatives thereof mentioned above. By “completely free” we mean to refer to coating compositions containing less than 20 parts per billion (ppb) of any of the compounds or derivatives thereof. 
     The coating composition of the present invention may have any suitable solids content. The coating composition may have a solids content of from 10 to 60% by weight of the coating composition, such as from 15 to 50 wt % or suitably from 20 to 40 wt %. 
     The metal packaging container is suitably a food or beverage metal packaging container. The metal packaging container is suitably an aerosol can, such as an aluminum monobloc aerosol. The packaging container is suitably a food or beverage packaging container, such as a food or beverage can. Examples of such food and/or beverage cans include, but are not limited to, two-piece cans, and/or three-piece cans and the like. Such cans may be formed from, for example, tin free steel, aluminum or tinplate. The food or beverage packaging coating container may suitably comprise an “easy open end” (EOE) or a “full aperture easy open end” (FAEOE). The aqueous coating composition or powder coating composition may be applied to any part of the food or beverage packaging container, such as the sidewalls, ends, or pull tabs etc. Suitably, the aqueous coating composition or powder coating composition may be applied to the EOE or FAEOE of the food or beverage packaging container. The aqueous coating composition or powder coating composition may be applied to the internal or external of the food or beverage packaging container. For example, the aqueous coating composition or powder coating composition may be used as an internal or external coating for food or beverage cans, such as a spray coating or roll coating. 
     The coating composition of the present invention may be applied to any suitable substrate. The coating composition may be applied to a metal substrate. Examples of suitable metal substrates include, but are not limited to, food and/or beverage packaging, components used to fabricate such packaging or monobloc aerosol cans and/or tubes. Suitably, the food and/or beverage packaging may be a can. Examples of cans include, but are not limited to, two-piece cans, and/or three-piece cans and the like. Suitable examples of monobloc aerosol cans and/or tubes include, but are not limited to, deodorant and hair spray containers. Monobloc aerosol cans and/or tubes may be aluminium monobloc aerosol cans and/or tubes. 
     The coating compositions may be applied to food and/or beverage packaging or components used to fabricate such packaging. 
     The coating compositions may be applied to monobloc aerosol cans and/or tubes. 
     The application of various pre-treatments and coatings to packaging is well established. Such treatments and/or coatings, for example, can be used in the case of metal cans, wherein the treatment and/or coating is used to retard or inhibit corrosion, provide a decorative coating, provide ease of handling during the manufacturing process, and the like. Coatings can be applied to the interior of such cans to prevent the contents from contacting the metal of the container. Contact between the metal and a food or beverage, for example, can lead to corrosion of a metal container, which can then contaminate the food or beverage. This is particularly true when the contents of the can are acidic in nature. The coatings applied to the interior of metal cans also help prevent corrosion in the headspace of the cans, which is the area between the fill line of the product and the can lid; corrosion in the headspace is particularly problematic with food products having a high salt content. Coatings can also be applied to the exterior of metal cans. Certain powder coatings of the present invention are particularly applicable for use with coiled metal stock, such as the coiled metal stock from which the ends of cans are made (“can end stock”), and end caps and closures are made (“cap/closure stock”). Since coatings designed for use on can end stock and cap/closure stock are typically applied prior to the piece being cut and stamped out of the coiled metal stock, they are typically flexible and extensible. For example, such stock is typically coated on both sides. Thereafter, the coated metal stock is punched. For can ends, the metal is then scored for the “pop-top” opening and the pop-top ring is then attached with a pin that is separately fabricated. The end is then attached to the can body by an edge rolling process. A similar procedure is done for “easy open” can ends. For easy open can ends, a score substantially around the perimeter of the lid allows for easy opening or removing of the lid from the can, typically by means of a pull tab. For caps and closures, the cap/closure stock is typically coated, such as by roll coating, and the cap or closure stamped out of the stock; it is possible, however, to coat the cap/closure after formation. Coatings for cans subjected to relatively stringent temperature and/or pressure requirements should also be resistant to popping, corrosion, blushing and/or blistering. 
     Accordingly, the present invention is further directed to a package coated at least in part with any of the coating compositions described above. A “package” is anything used to contain another item, particularly for shipping from a point of manufacture to a consumer, and for subsequent storage by a consumer. A package will be therefore understood as something that is sealed so as to keep its contents free from deterioration until opened by a consumer. The manufacturer will often identify the length of time during which the food or beverage will be free from spoilage, which typically ranges from several months to years. Thus, the present “package” is distinguished from a storage container or bakeware in which a consumer might make and/or store food; such a container would only maintain the freshness or integrity of the food item for a relatively short period. A package according to the present invention can be made of metal or non-metal, for example, plastic or laminate, and be in any form. An example of a suitable package is a laminate tube. Another example of a suitable package is metal can. The term “metal can” includes any type of metal can, container or any type of receptacle or portion thereof that is sealed by the food and/or beverage manufacturer to minimize or eliminate spoilage of the contents until such package is opened by the consumer. One example of a metal can is a food can; the term “food can(s)” is used herein to refer to cans, containers or any type of receptacle or portion thereof used to hold any type of food and/or beverage. The term “metal can(s)” specifically includes food cans and also specifically includes “can ends” including “E-Z open ends”, which are typically stamped from can end stock and used in conjunction with the packaging of food and beverages. The term “metal cans” also specifically includes metal caps and/or closures such as bottle caps, screw top caps and lids of any size, lug caps, and the like. The metal cans can be used to hold other items as well, including, but not limited to, personal care products, bug spray, spray paint, and any other compound suitable for packaging in an aerosol can. The cans can include “two piece cans” and “three-piece cans” as well as drawn and ironed one-piece cans; such one piece cans often find application with aerosol products. Packages coated according to the present invention can also include plastic bottles, plastic tubes, laminates and flexible packaging, such as those made from PE, PP, PET and the like. Such packaging could hold, for example, food, toothpaste, personal care products and the like. 
     The coating can be applied to the interior and/or the exterior of the package. The coating could also be applied as a rim coat to the bottom of the can. The rim coat functions to reduce friction for improved handling during the continued fabrication and/or processing of the can. The coating can also be applied to caps and/or closures; such application can include, for example, a protective varnish that is applied before and/or after formation of the cap/closure and/or a pigmented enamel post applied to the cap, particularly those having a scored seam at the bottom of the cap. Decorated can stock can also be partially coated externally with the coating described herein, and the decorated, coated can stock used to form various metal cans. 
     Metal coils, having wide application in many industries, are also substrates that can be coated according to the present invention. Coil coatings also typically comprise a colorant. 
     The coating composition according to the present invention may be applied to at least a portion of the metal substrate. For example, when the coating composition is applied to a monobloc aerosol tube and/or can, the coating composition may be applied to at least a portion of an internal surface of said tube and/or can. 
     The aqueous coating composition or powder coating composition may be applied as a repair coating for component parts of food and beverage cans. For example, as a repair coating for a full aperture easy open end for food cans. This end component may repair coated, after fabrication, by airless spraying of the material on to the exterior of the score line. Other uses as repair coatings include the coating of seams and welds, such as side seams for which the coating may be applied to the area by spraying (airless or air driven) or roller coating. Repair coating can also include protection of vulnerable areas where corrosion may be likely due to damage, these areas include flanges, rims and bottom rims where the coating may be applied by spraying, roller coating flow or dip coating. 
     The aqueous coating composition or powder coating composition of the present invention may be applied to the substrate, or a portion thereof, as a single layer or as part of a multi layer system. The aqueous coating composition or powder coating composition may be applied as a single layer. The aqueous coating composition or powder coating composition may be applied to an uncoated substrate. For the avoidance of doubt an uncoated substrate extends to a surface that is cleaned prior to application. The aqueous coating composition or powder coating composition may be applied on top of another paint layer as part of a multi layer system. For example, the aqueous coating composition or powder coating composition may be applied on top of a primer. The aqueous coating composition or powder coating composition may form an intermediate layer or a top coat layer. The aqueous coating composition or powder coating composition may be applied as the first coat of a multi coat system. Suitably, the aqueous coating composition or powder coating composition may be applied as an undercoat or a primer. The second, third, fourth etc. coats may comprise any suitable paint such as those containing, for example, epoxy resins; polyester resins; polyurethane resins; polysiloxane resins; hydrocarbon resins or combinations thereof. The second, third, fourth etc. coats may comprise polyester resins. The second, third, fourth etc. coats may be a liquid coating or a powder coating. 
     It will be appreciated by a person skilled in the art that the aqueous coating composition or powder coating composition may be applied before or after forming the metal packaging container. For example, the aqueous coating composition may be applied to metal substrate which is then shaped and formed into a metal packaging container, or the aqueous coating composition or powder coating composition may be applied to the preformed packaging container. 
     The aqueous coating composition or powder coating composition may be applied to a substrate once or multiple times. 
     “Powder” and like terms, as used herein, refers to materials that are in the form of solid particulates, as opposed to materials which are in the liquid form. 
     Powder coating compositions of the present invention may be applied by any suitable method. Methods of applying said powder coating compositions will be well known to a person skilled in the art. Suitable application methods include, such as electrostatic spraying, or applied by ultra corona discharge for example. Suitably, the powder coating compositions according to the present invention may be applied by ultra corona discharge. 
     When the substrate is electrically conductive, the powder coating composition is typically electrostatically applied. Electrostatic spray application generally involves drawing the coating composition from a fluidized bed and propelling it through a corona field. The particles of the coating composition become charged as they pass through the corona field and are attracted to and deposited upon the electrically conductive substrate, which is grounded. As the charged particles begin to build up, the substrate becomes insulated, thus limiting further particle deposition. 
     Powder coating compositions according to the present invention may be applied to any suitable dry film thickness. The powder coating compositions according to the present invention may be applied to a dry film thickness from 0.1 μm (microns) to 1000 μm, suitably from 3 μm to 500 μm, such as from 5 μm to 250 μm, or even from 5 μm to 150 μm, such as from 10 μm to 100 μm. 
     The powder component of the present invention may have an average particle size of less than 15 microns (μm). The powder component may have an average particle size of less than 12 μm, suitably, less than 10 μm, such as less than 7.5 μm, or even less than 5 μm. For the avoidance of doubt the term “less than” includes particles having the stated average particle size. For example, “less than 15 μm” refers to particles having an average particle size of 15 μm as well as those having an average particle size below this value. 
     Particles having these sizes may be produced by any suitable method. Suitable methods will be well known to a person skilled in the art. Examples of suitable methods include, but are not limited to, cold grinding, milling and sieving methods. 
     The coating compositions of the present invention may comprise a liquid carrier in which the powder component, such as acid functional polyester materials, is dispersed. For the avoidance of doubt, a dispersion is a powder suspended in a liquid. The coating compositions may comprise any suitable liquid carrier. The liquid carrier may comprise water, an organic solvent, a mixture of water and one or more organic solvent(s) or a mixture of organic solvents. Suitably, the liquid carrier may comprise water. 
     The aqueous coating composition or powder coating composition according to the present invention may be applied to the substrate by any suitable method. Methods of applying the aqueous coating composition or powder coating composition according to the present invention will be well known to a person skilled in the art. Suitable application methods for the aqueous coating composition or powder coating composition of the present invention include, but are not limited to the following: electrocoating; spraying; electrostatic spraying; dipping; rolling; brushing; and the like. 
     The aqueous coating composition or powder coating composition of the present invention may be applied to any suitable dry film thickness. The aqueous coating composition or powder coating composition of the present invention may be applied to a dry film thickness from 2 to 40 microns (μm). 
     As used herein, unless otherwise expressly specified, all numbers such as those expressing values, ranges, amounts or percentages may be read as if prefaced by the word “about”, even if the term does not expressly appear. Also, any numerical range recited herein is intended to include all sub-ranges subsumed therein. Singular encompasses plural and vice versa. For example, although reference is made herein to “a” first polyester material, “an” aqueous coating composition or “a” powder coating composition, “an” undercoat aqueous coating composition, “an” isocyanate resin, “the” residue of “an”, and the like, one or more of each of these and any other components can be used. Reference to “one of the polyacid component or the polyol component comprises a functional monomer” refers to either or both of the polyacid component and/or the polyol component comprising a functional monomer. As used herein, the term “polymer” refers to oligomers and both homopolymers and copolymers, and the prefix “poly” refers to two or more. Including, for example and like terms means including for example but not limited to. Additionally, although the present invention has been described in terms of “comprising”, the processes, materials, and aqueous coating compositions or powder coating compositions detailed herein may also be described as “consisting essentially of” or “consisting of”. 
     According to the present invention, there is provided an acrylic polyester resin, obtainable by grafting an acrylic polymer with a polyester material, the polyester material being obtainable by polymerizing:
         i) a polyacid component, comprising an ethylenically unsaturated functional monomer operable to impart ethylenically unsaturated functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said ethylenically unsaturated functionality, with   ii) a polyol component   wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol and wherein the acrylic polyester resin has a Tg of at least 25° C.       

     According to the present invention, there is provided an acrylic modified polyester resin, obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
         i) a polyacid component, comprising an ethylenically unsaturated functional monomer operable to impart ethylenically unsaturated functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said ethylenically unsaturated functionality, wherein the ethylenically unsaturated functional monomer comprises: maleic acid, maleic anhydride and/or fumaric acid; with   ii) a polyol component,   wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol   and wherein the acrylic polyester resin has a Tg of at least 25° C.       

     According to the present invention, there is provided an acrylic modified polyester resin, obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
         i) a polyacid component, comprising an ethylenically unsaturated functional monomer operable to impart ethylenically unsaturated functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said ethylenically unsaturated functionality, wherein the ethylenically unsaturated functional monomer comprises: maleic acid, maleic anhydride and/or fumaric acid;
           the polyacid component further comprising sulfonated monomer comprises: 5-(sodiosulfo)-isophthalic acid, dimethyl 5-(sodiosulfo)isophalate, 5-(lithiosulfo)isophthalic acid, and/or bis(2-hydroxyethyl)-5-(sodiosulfo)isophthalate; with   ii) a polyol component,   
           wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   and wherein the acrylic polyester resin has a Tg of at least 25° C.       

     According to the present invention, there is provided an aqueous coating composition or powder coating composition, the aqueous coating composition or powder coating composition comprising:
         a) an acrylic modified polyester resin, obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
           i) a polyacid component, comprising an ethylenically unsaturated functional monomer operable to impart ethylenically unsaturated functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said ethylenically unsaturated functionality, with   ii) a polyol component,   
           wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   b) a crosslinking material,   and wherein a coating formed from the coating composition has a Tg of at least 25° C.       

     According to the present invention, there is provided an aqueous coating composition or powder coating composition, the aqueous coating composition or powder coating composition comprising:
         a) an acrylic modified polyester resin, obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
           i) a polyacid component, comprising an ethylenically unsaturated functional monomer operable to impart ethylenically unsaturated functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said ethylenically unsaturated functionality, wherein the ethylenically unsaturated functional monomer comprises: maleic acid, maleic anhydride and/or fumaric acid; with   ii) a polyol component,   
           wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   b) a crosslinking material,   and wherein a coating formed from the coating composition has a Tg of at least 25° C.       

     According to the present invention, there is provided an aqueous coating composition or powder coating composition, the aqueous coating composition or powder coating composition comprising:
         a) an acrylic modified polyester resin, obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
           i) a polyacid component, comprising an ethylenically unsaturated functional monomer operable to impart ethylenically unsaturated functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said ethylenically unsaturated functionality, wherein the ethylenically unsaturated functional monomer comprises: maleic acid, maleic anhydride and/or fumaric acid;
               the polyacid component further comprising sulfonated monomer comprises: 5-(sodiosulfo)-isophthalic acid, dimethyl 5-(sodiosulfo)isophalate, 5-(lithiosulfo)isophthalic acid, and/or bis(2-hydroxyethyl)-5-(sodiosulfo)isophthalate; with   
               ii) a polyol component,   
           wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   b) a crosslinking material,   and wherein a coating formed from the coating composition has a Tg of at least 25° C.       

     According to the present invention, there is provided a metal packaging container coated on at least a portion thereof with a coating, the coating being derived from an aqueous coating composition or powder coating composition, the aqueous coating composition or powder coating composition comprising:
         a) an acrylic modified polyester resin, obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
           i) a polyacid component, comprising an ethylenically unsaturated functional monomer operable to impart ethylenically unsaturated functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said ethylenically unsaturated functionality, with   ii) a polyol component,   
           wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   b) a crosslinking material,   and wherein the coating has a Tg of at least 25° C.       

     According to the present invention, there is provided a metal packaging container coated on at least a portion thereof with a coating, the coating being derived from an aqueous coating composition or powder coating composition, the aqueous coating composition or powder coating composition comprising:
         a) an acrylic modified polyester resin, obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
           i) a polyacid component, comprising an ethylenically unsaturated functional monomer operable to impart ethylenically unsaturated functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said ethylenically unsaturated functionality, wherein the ethylenically unsaturated functional monomer comprises: maleic acid, maleic anhydride and/or fumaric acid; with   ii) a polyol component,   
           wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   b) a crosslinking material,   and wherein the coating has a Tg of at least 25° C.       

     According to the present invention, there is provided a metal packaging container coated on at least a portion thereof with a coating, the coating being derived from an aqueous coating composition or powder coating composition, the aqueous coating composition or powder coating composition comprising:
         a) an acrylic modified polyester resin, obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
           i) a polyacid component, comprising an ethylenically unsaturated functional monomer operable to impart ethylenically unsaturated functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said ethylenically unsaturated functionality, wherein the ethylenically unsaturated functional monomer comprises: maleic acid, maleic anhydride and/or fumaric acid;
               the polyacid component further comprising sulfonated monomer comprises: 5-(sodiosulfo)-isophthalic acid, dimethyl 5-(sodiosulfo)isophalate, 5-(lithiosulfo)isophthalic acid, and/or bis(2-hydroxyethyl)-5-(sodiosulfo)isophthalate; with   
               ii) a polyol component,   
           wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   b) a crosslinking material,   and wherein the coating has a Tg of at least 25° C.       

     According to the present invention, there is provided a food or beverage packaging container coated on at least a portion thereof with a coating, the coating being derived from an aqueous coating composition or powder coating composition, the aqueous coating composition or powder coating composition comprising:
         a) an acrylic modified polyester resin, obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
           i) a polyacid component, comprising an ethylenically unsaturated functional monomer operable to impart ethylenically unsaturated functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said ethylenically unsaturated functionality, wherein the ethylenically unsaturated functional monomer comprises: maleic acid, maleic anhydride and/or fumaric acid;
               the polyacid component further comprising sulfonated monomer comprises: 5-(sodiosulfo)-isophthalic acid, dimethyl 5-(sodiosulfo)isophalate, 5-(lithiosulfo)isophthalic acid, and/or bis(2-hydroxyethyl)-5-(sodiosulfo)isophthalate; with   
               ii) a polyol component,   
           wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   b) a crosslinking material,   and wherein the coating has a Tg of at least 25° C.       

     According to the present invention there is provided a method of forming an acrylic modified polyester resin, the method comprising polymerizing an acrylic modification polymer in the presence of a polyester material, the polyester material being obtainable by polymerizing
         i) a polyacid component, with   ii) a polyol component,   wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said functionality, and wherein the acrylic polyester resin has a Tg of at least 25° C.       

     According to the present invention there is provided a method of forming an acrylic modified polyester resin, the method comprising polymerizing an acrylic modification polymer in the presence of a polyester material, the polyester material being obtainable by polymerizing
         i) a polyacid component, comprising an ethylenically unsaturated functional monomer operable to impart ethylenically unsaturated functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said ethylenically unsaturated functionality, with   ii) a polyol component,   wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms, and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   and wherein the acrylic polyester resin has a Tg of at least 25° C.       

     According to the present invention there is provided a method of preparing an aqueous coating composition, the method comprising dispersing an acrylic modified polyester resin and a crosslinking material in an aqueous medium, the acrylic modified polyester resin being obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
         i) a polyacid component, with   ii) a polyol component,   wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said functionality,   and wherein a coating formed from the coating composition has a Tg of at least 25° C.       

     According to the present invention there is provided a method of preparing an aqueous coating composition, the method comprising dispersing an acrylic modified polyester resin and a crosslinking material in an aqueous medium, the acrylic modified polyester resin being obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
         i) a polyacid component, comprising an ethylenically unsaturated functional monomer operable to impart ethylenically unsaturated functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said ethylenically unsaturated functionality, with   ii) a polyol component,   wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   and wherein a coating formed from the coating composition has a Tg of at least 25° C.       

     According to the present invention there is provided a method of coating at least a portion of a metal packaging container, the method comprising applying an aqueous coating composition or powder coating composition to a metal packaging composition, the aqueous coating composition or powder coating composition comprising an acrylic modified polyester resin and a crosslinking material, the acrylic modified polyester resin being obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
         i) a polyacid component, with   ii) a polyol component,   wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said functionality, and
 
curing the aqueous coating composition or powder coating composition to form a coating,
       

     and wherein the coating has a Tg of at least 25° C. 
     According to the present invention there is provided a method of coating at least a portion of a metal packaging container, the method comprising applying an aqueous coating composition or powder coating composition to a metal packaging composition, the aqueous coating composition or powder coating composition comprising an acrylic modified polyester resin and a crosslinking material, the acrylic modified polyester resin being obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
         i) a polyacid component, comprising an ethylenically unsaturated functional monomer operable to impart ethylenically unsaturated functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said ethylenically unsaturated functionality, with   ii) a polyol component,   wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;
 
and curing the aqueous coating composition or powder coating composition to form a coating,
   and wherein the coating has a Tg of at least 25° C.       

     All of the features contained herein may be combined with any of the aspects herein and in any combination. 
     For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the following theoretical experimental data. 
    
    
     EXAMPLES 
     Method for the formation of the coating composition. The details of inventive aqueous coating 1a and 2a, and comparative aqueous coating 3a, are shown in Tables 1 to 4. Coating 1a shows unsaturated, hydroxyl functional polyesters with a Tg enhancing monomer. Coating 2a shows unsaturated, hydroxyl functional polyesters with a Tg enhancing monomer and a dimer fatty acid (Pripol 1010). Comparative coating 3a shows an unsaturated, hydroxyl functional polyester without a Tg enhancing monomer. 
     The polyester materials of inventive coatings 1a, 2a and comparative coating 3a are formed as follows. The diol, diacid and catalyst components listed in Table 1 are added as a batch to a vessel with a steam column, distillation head and condenser. The batch temperature is increased to 150° C. with stirring at 400 rpm under an N 2  blanket. Once the temperature reaches 150° C., the batch temperature is increased to 230° C. over a 4 hour period (10° C. steps every 30 minutes), whilst ensuring that the head temperature is below 100° C. 
     Once the batch reaches 230° C., the acid value is assessed every hour. When the acid value is less than 15, the batch is cooled to 150° C. and methyl hydroquinone is added, then after 10 minutes, the maleic anhydride is added and the batch temperature increased to 195° C. until the acid value increases up to &lt;20. The batch is then cooled to 130° C. and azeotropically separated using a Dean Stark trap and an addition of xylene. 
     The batch is then heated back up to 195° C. When the target AV and cut viscosity is reached the batch is cooled to 150° C. and the Dowanol DPM added. The batch is then held at 150° C. for 1 hour and then poured out. 
     The polyester materials formed then undergo a grafting process to graft acrylic onto the unsaturated functionality of the backbone of the polyester (imparted by the maleic anhydride) to form acrylic modified polyester resins 1a, 2a (noted simply as PGA resins 1a to 2a in Table 2). Details of the monomers used in the acrylic graft reaction are shown in Table 2. 
     The acrylic modified polyester resins are then each formed as follows. Half of the amount of the polyester material given in Table 2 is added to a vessel with mixing at 225 rpm and heated to 120° C. Once at 120° C., half of total amount of each acrylic monomer as shown in Table 2 is added over a period of 40 minutes with continued stirring. 10 minutes after adding the acrylic monomers, about a third of each of the t-butyl peroctoate initiator and Dowanol DPM amounts as shown in Table 2 is added. The remaining amount of the polyester material is then added and the solution heated back to 120° C. At this stage the solution is homogeneous and has good mixing. Then the remaining acrylic monomers are added over 40 minutes. 10 minutes after adding the acrylic monomers, about a third of each of the t-butyl peroctoate initiator and Dowanol DPM amounts as shown in Table 2 are added over a 30 minute period. The remaining t-butyl peroctoate initiator and Dowanol DPM is then added in two evenly split batches, the first batch is added over 5 minutes and the mixture then held at 120° C. for 30 minutes before addition of the second batch over 5 minutes and then held at 120° C. for 30 minutes. The reaction mixture is then cooled to below 100° C. 
     The acrylic modified polyester resins are formed into aqueous dispersions with the components as shown in Table 3. 
     The acrylic modified polyester resins are formed into aqueous dispersions by heating the resin to 90° C., and during heating the DMEA is added with stirring. The mixture is then held for 10 minutes, after which deionized water is added over 60 minutes, maintaining the temperature about 85° C. The aqueous dispersions is then allowed to cool to 45° C. 
     The aqueous dispersions are formed into aqueous coating compositions with components as shown in Table 4, as follows. The deionized water, Dowanol PnB, crosslinking material (Cymel 1123-benzoguanamine, commercially available from Allnex), and blocked DDBSA catalyst (Nacure 5925, commercially available from King) are stirred into the aqueous dispersion to form the aqueous coating composition. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Polyesters 
               
            
           
           
               
               
               
            
               
                   
                 Polyester 
                 Polyester 
               
               
                 Materials 
                 1a 
                 2a 
               
               
                   
               
            
           
           
               
               
               
            
               
                 2-methyl-1,3-propanediol 
                 75.58 
                 — 
               
               
                 Cyclohexane dimethanol 
                 — 
                 117.69 
               
               
                 isosorbide 
                 73.11 
                 39.21 
               
               
                 Trimethylolpropane 
                 1.82 
                 1.88 
               
               
                 Isophthalic acid 
                 51.22 
                 121.10 
               
               
                 Pripol 1010 (C36 Dimer Acid) 
                 — 
                 123.93 
               
               
                 Hexahydrophthalic anhydride 
                 38.91  
                 — 
               
               
                 Dibutyl tin oxide 
                 0.18 
                 0.17 
               
               
                 Cyclohexane-1,4-dicarboxylic acid 
                 110.41 
                 — 
               
               
                 MeHQ 
                 0.04 
                 0.036 
               
               
                 Maleic anhydride 
                 12.06 
                 10.55 
               
               
                 Xylene 
                 24.74 
                 21.75 
               
               
                 Dowanol DPM 
                 230.51 
                 284.40 
               
               
                 Properties 
                   
                   
               
               
                 Initial weight 
                 361.92 
                 414.21 
               
               
                 Theoretical weight loss 
                 40.80 
                 32.04 
               
               
                 Final resin weight 
                 321.13 
                 382.17 
               
               
                 Total with solids 
                 576.33 
                 688.07 
               
               
                 % solids 
                 55.72 
                 55.54 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Polyester-graft-acrylic (PGA) Resins 
               
            
           
           
               
               
               
               
            
               
                   
                   
                 PGA 
                 PGA 
               
               
                   
                   
                 resin 1a 
                 resin 2a 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Materials 
                   
                   
               
               
                   
                 Polyester 1a 
                 286.12 
                 — 
               
               
                   
                 Polyester 2a 
                 — 
                 276.66 
               
               
                   
                 Comparative polyester 3a 
                 — 
                 — 
               
               
                   
                 Methacrylic acid 
                 17.72 
                 17.72 
               
               
                   
                 Ethyl methacrylate 
                 16.24 
                 16.24 
               
               
                   
                 Methyl methacrylate 
                 16.24 
                 16.24 
               
               
                   
                 2-hydroxyethyl 
                 8.86 
                 8.86 
               
               
                   
                 methacrylate 
                   
                   
               
               
                   
                 t-butyl peroctoate 
                 5.32 
                 5.32 
               
               
                   
                 Dowanol DPM 
                 26.58 
                 26.58 
               
               
                   
                 Properties 
                   
                   
               
               
                   
                 Final % solids 
                 59.00 
                 59.00 
               
               
                   
                 % polyester 
                 70.52 
                 70.52 
               
               
                   
                 % acrylic 
                 27.81 
                 27.81 
               
               
                   
                 % initiator 
                 1.67 
                 1.67 
               
               
                   
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Aqueous Dispersions 
               
            
           
           
               
               
               
            
               
                   
                 Aq.  
                 Aq. 
               
               
                   
                 Dispersion 1a 
                 Dispersion 2a 
               
               
                   
               
            
           
           
               
               
               
            
               
                 Materials 
                   
                   
               
               
                 PGA resin 1a 
                 250.08 
                 — 
               
               
                 PGA resin 2a 
                 — 
                 241.67 
               
               
                 Comparative PGA  
                 — 
                 — 
               
               
                 resin 3a 
                   
                   
               
               
                 Dimethylethanolamine 
                 9.33 
                 9.71 
               
               
                 Deionised water 
                 210.11 
                 213.80 
               
               
                 Properties 
                   
                   
               
               
                 % solids 
                 24.36 
                 23.44 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Coating Compositions 
               
            
           
           
               
               
               
            
               
                   
                 Aq. 
                 Aq. 
               
               
                   
                 Coating 1a 
                 Coating 2a 
               
               
                   
               
            
           
           
               
               
               
            
               
                 Aq. dispersion 1a 
                 40.00 
                 — 
               
               
                 Aq. dispersion 2a 
                 — 
                 40.00 
               
               
                 Comparative aq. dispersion 3a 
                 — 
                 — 
               
               
                 DI Water 
                 3.02 
                 1.25 
               
               
                 Dowanol PnB 
                 1.09 
                 1.04 
               
               
                 Cymel 1123 
                 1.08 
                 1.04 
               
               
                 (benzoguanamine) 
                   
                   
               
               
                 Nacure 5925 
                 0.04 
                 0.04 
               
               
                 (blocked DDBSA) 
                   
                   
               
               
                 Total 
                 45.23 
                 43.37 
               
               
                   
               
            
           
         
       
     
     Testing Methods 
     Coated panels are obtained by drawing the aqueous coatings over a Zirconium pretreated 5182-H48 aluminum panels using a wire wound rod to obtain dry coating weights of approximately 7.0 mg/square inch (msi). The coated panels are immediately placed into a one-zone, gas-fired, convey or oven for 10 seconds and baked to a peak metal temperature of 450° F. (232° C.). 
     A coating formed from the coating composition of the present invention may be able to provide good blush resistance, such as a blush resistance of at least 8 or at least 9. Blush resistance measures the ability of a coating to resist attack by various testing solutions. When the coated film absorbs test solution, it generally becomes cloudy or looks white. Blush is measured visually using a scale of 1-10 where a rating of “10” indicates no blush and a rating of “0” indicates complete whitening of the film. Blush ratings of at least 7 are typically desired for commercially viable coatings. The coated panel tested is 2×4 inches (5×10 cm) and the testing solution covers half of the panel being tested so you can compare blush of the exposed panel to the unexposed portion. 
     A coating formed from the coating composition of the present invention may be able to provide good adhesion, such as an adhesion of at least 3, or at least 4. Adhesion testing is performed to assess whether the coating adheres to the substrate. The adhesion test is performed according to ASTM D 3359 Test Method B, using Scotch 610 tape, available from 3M Company of Saint Paul, Minn. Adhesion is generally rated on a scale of 0-5 where a rating of “5” indicates no adhesion failure. 
     A coating formed from the coating composition of the present invention may be able to provide good resistance to acetic acid, such as an adhesion of at least 3, or at least 4. The “Acetic Acid” test is designed to measure the resistance of a coating to a boiling 3% acetic acid solution. The solution is prepared by mixing 90 grams of Glacial Acetic Acid (product of Fisher Scientific) into 3000 grams of deionized water. Coated strips are immersed into the boiling Acetic Acid solution for 30 minutes. The strips are then rinsed and cooled in deionized water, dried, and immediately rated for adhesion as described previously. 
     A coating formed from the coating composition of the present invention may be able to provide a good resistance to a boiling detergent solution, such as a blush resistance of at least 8 or at least 9, and/or an adhesion of at least 3, or at least 4. The “Dowfax” test is designed to measure the resistance of a coating to a boiling detergent solution. The solution is prepared by mixing 5 grams of DOWFAX 2A1 (product of Dow Chemical) into 3000 grams of deionized water. Coated strips are immersed into the boiling Dowfax solution for 15 minutes. The strips are then rinsed and cooled in deionized water, dried, and immediately rated for blush and adhesion as described previously. 
     A coating formed from the coating composition of the present invention may be able to provide a good resistance to Joy detergent solution, such as a blush resistance of at least 8 or at least 9, and/or an adhesion of at least 3 or at least 4. The “Joy” test is designed to measure the resistance of a coating to a hot 180° F. (82° C.) Joy detergent solution. The solution is prepared by mixing 30 grams of Ultra Joy Dishwashing Liquid (product of Procter &amp; Gamble) into 3000 grams of deionized water. Coated strips are immersed into the 180° F. (82° C.) Joy solution for 15 minutes. The strips are then rinsed and cooled in deionized water, dried, and immediately rated for blush and adhesion as described previously. 
     A coating formed from the coating composition of the present invention may be able to provide a good resistance to deionized water, such as a blush resistance of at least 8 or at least 9, and/or an adhesion of at least 3, or at least 4. The “DI Water Retort” test is designed to measure the resistance of a coating to deionized water. Coated strips are immersed into the deionized water and placed in a steam retort for 30 minutes at 250° F. (121° C.). The strips are then cooled in deionized water, dried, and immediately rated for blush and adhesion as described previously. 
     Certain aspects of the invention may be combined in the following combinations.
     1. An acrylic polyester resin, obtainable by grafting an acrylic polymer with a polyester material, the polyester material being obtainable by polymerizing:
       i) a polyacid component, with   ii) a polyol component,   wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   (x) an aliphatic polyacid or polyol monomer wherein the monomer comprises a tetracyclic hydrocarbon ring structure;   wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted with the polyester material via the use of said functionality, and wherein the acrylic polyester resin has a Tg of at least 25° C.   
       2. An aqueous coating composition or powder coating composition, the aqueous coating composition or powder coating composition comprising:
       a) an acrylic polyester resin, obtainable by grafting an acrylic polymer with a polyester material, the polyester material being obtainable by polymerizing:
           i) a polyacid component, with   ii) a polyol component,   
           wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   (x) an aliphatic polyacid or polyol monomer wherein the monomer comprises a tetracyclic hydrocarbon ring structure;
           wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted with the polyester material via the use of said functionality,   
           b) a crosslinking material,   and wherein a coating formed from the coating composition has a Tg of at least 25° C.   
       3. A metal packaging container coated on at least a portion thereof with a coating, the coating being derived from an aqueous coating composition or powder coating composition, the aqueous coating composition or powder coating composition comprising:
       a) an acrylic polyester resin, obtainable by grafting an acrylic polymer with a polyester material, the polyester material being obtainable by polymerizing:
           i) a polyacid component, with   ii) a polyol component,   
           wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   (x) an aliphatic polyacid or polyol monomer wherein the monomer comprises a tetracyclic hydrocarbon ring structure;
           wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted with the polyester material via the use of said functionality,   
           b) a crosslinking material,   and wherein the coating has a Tg of at least 25° C.   
       4. A packaging coated on at least a portion thereof with a coating, the coating being derived from an aqueous coating composition or powder coating composition, the aqueous coating composition or powder coating composition comprising:
       a) an acrylic polyester resin, obtainable by grafting an acrylic polymer with a polyester material, the polyester material being obtainable by polymerizing:
           i) a polyacid component, with   ii) a polyol component,   
           wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   (x) an aliphatic polyacid or polyol monomer wherein the monomer comprises a tetracyclic hydrocarbon ring structure;
           wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted with the polyester material via the use of said functionality,   
           b) a crosslinking material,   and wherein the coating has a Tg of at least 25° C.   
       5 A resin, coating composition or packaging according to any preceding aspect, wherein the functional monomer comprises an ethylenically unsaturated monomer.   6. A resin, coating composition or packaging according to any preceding aspect, wherein the functional monomer comprises: maleic acid, maleic anhydride, fumaric acid, itaconic anhydride, itaconic acid, citraconic anhydride, citraconic acid, aconitic acid, aconitic anhydride, oxalocitraconic acid, oxalocitraconic anhydride, mesaconic acid, mesaconic anhydride, phenyl maleic acid, phenyl maleic anhydride, t-butyl maleic acid, t-butyl maleic anhydride, monomethyl fumarate, monobutyl fumarate, nadic acid, nadic anhydride, methyl maleic acid, methyl maleic anhydride, and/or trimethylolpropane monoallyl ether.   7. A resin, coating composition or packaging according to any preceding aspect, wherein the functional monomer is present as a proportion of the dry weight of the polyol or polyacid component, such as the polyacid component, in an amount of from 0.5 to 10 wt %, suitably from 1 to 5 wt %.   8. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises:
       (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring,   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   
       9. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises:
       (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol.   
       10. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises:
       (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom,   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring,   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol.   
       11. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises:
       (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom, and/or   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring.   
       12. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises:
       (ii) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof; and/or   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring.   
       13. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises:
       (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol; and/or   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof.   
       14. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises monomer (i): an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof.   15. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises monomer (ii): a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom.   16. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises monomer (iii): an optionally substituted furan group-containing polyacid or polyol.   17. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises monomer (iv): an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring.   18. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises monomer (v): an optionally substituted bridged tricyclodecane group-containing polyacid or polyol.   19. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises monomer (vi): an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof.   20. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises monomer (vii): an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol.   21. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises monomer (viii): a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms.   22. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises monomer (ix): an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol.   23. A resin, coating composition or packaging according to any preceding aspect, wherein the hydrogenated derivative of Tg enhancing monomer (i) is saturated.   24. A resin, coating composition or packaging according to any preceding aspect, wherein monomer (ii) comprises two optionally substituted 6 membered aromatic cyclic groups that are directly bonded and/or monomer (ii) comprises two optionally substituted 6 membered alicyclic cyclic groups that are separated by one carbon atom, suitably, the alicyclic groups of monomer (ii) are cycloalkyl.   25. A resin, coating composition or packaging according to any preceding aspect, wherein monomer (iv) comprises a heteroatom in a ring, suitably one heteroatom in each ring, and suitably the heteroatoms are oxygen or nitrogen atoms, such as oxygen atoms.   26. A resin, coating composition or packaging according to any preceding aspect, wherein the branched alkyl group-containing monomer (viii) are formed of from 5 to 8 carbon atoms, such as from 5 to 7 carbon atoms, 5 to 6 carbon atoms or 5 carbon atoms.   27. A resin, coating composition or packaging according to any preceding aspect, wherein the optional substituents of the Tg enhancing monomers are alkyl, such as from 1 to 3 carbon atoms, suitably 1 or 2 carbon atoms, suitably 1 carbon atom.   28. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, hydrogenated 1,8 dihydroxy naphthalene, hydrogenated bisphenol A, 2-(2-carboxyphenyl)-benzoic acid, 2,5 furandicarboxylic acid, isosorbide, isomannide, tricyclodecane dimethanol, tricyclodecane diol, tricyclocdecane polycarboxylic acid, nadic methyl acid, nadic acid, chlorendic anhydride, cyclohexane dimethanol, cyclohexane diol, 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, dimethyl-1,4-cyclochexane dicarboxylate, neopentyl glycol, 3,9-Bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, isophthalic acid, phthalic acid; isophthalic acid; 5-tert-butylisophthalic acid; tetrachlorophthalic acid; tetrahydrophthalic acid; hexahydrophthalic acid; methylhexahydrophthalic acid; endomethylene tetrahydrophthalic acid; endoethylene hexahydrophthalic acid; orthophthalic acid; phthalic anhydride; tetrahydrophthalic anhydride; dimethyl orthophthalate and/or terephalic acid and/or esters and/or anhydrides/acids of all the aforementioned acids/anhydrides.   29. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, hydrogenated 1,8 dihydroxy naphthalene, hydrogenated bisphenol A, 2-(2-carboxyphenyl)-benzoic acid, 2,5 furandicarboxylic acid, isosorbide, isomannide, tricyclodecane dimethanol, tricyclodecane diol, tricyclocdecane polycarboxylic acid, nadic methyl anhydride, nadic acid, chlorendic anhydride, nadic anhydride, cyclohexane dimethanol, cyclohexane diol, 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, dimethyl-1,4-cyclochexane dicarboxylate 3,9-Bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, isophthalic acid, phthalic acid; isophthalic acid; 5-tert-butylisophthalic acid; tetrachlorophthalic acid; tetrahydrophthalic acid; hexahydrophthalic acid; methylhexahydrophthalic acid; endomethylene tetrahydrophthalic acid; endoethylene hexahydrophthalic acid; orthophthalic acid; phthalic anhydride; tetrahydrophthalic anhydride; dimethyl orthophthalate and/or terephalic acid.   30. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, hydrogenated 1,8 dihydroxy naphthalene, hydrogenated bisphenol A, 2-(2-carboxyphenyl)-benzoic acid, 2,5 furandicarboxylic acid, isosorbide, isomannide, tricyclodecane dimethanol, tricyclodecane diol, tricyclocdecane polycarboxylic acid, nadic methyl anhydride, nadic acid, chlorendic anhydride, nadic anhydride 3,9-Bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, isophthalic acid, and/or terephalic acid.   31. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, hydrogenated 1,8 dihydroxy naphthalene, hydrogenated bisphenol A, 2-(2-carboxyphenyl)-benzoic acid, 2,5 furandicarboxylic acid, isosorbide, isomannide, tricyclodecane dimethanol, tricyclodecane diol, tricyclocdecane polycarboxylic acid, nadic methyl anhydride, nadic acid, nadic anhydride, and/or 3,9-Bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane.   32. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, hydrogenated 1,8 dihydroxy naphthalene, hydrogenated bisphenol A, 2-(2-carboxyphenyl)-benzoic acid, isosorbide, isomannide, tricyclodecane dimethanol, tricyclodecane diol, tricyclocdecane polycarboxylic acid, nadic methyl anhydride, nadic acid, and/or nadic anhydride.   33. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, hydrogenated 1,8 dihydroxy naphthalene, hydrogenated bisphenol A, 2-(2-carboxyphenyl)-benzoic acid, isosorbide, and/or isomannide.   34. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, hydrogenated 1,8 dihydroxy naphthalene, isosorbide, and/or isomannide.   35. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer comprises tricyclodecane dimethanol, tricyclodecane diol, tricyclocdecane polycarboxylic acid, nadic methyl anhydride, nadic acid, and/or nadic anhydride.   36. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer may comprise tricyclodecane dimethanol, tricyclodecane diol, nadic methyl anhydride, nadic acid, and/or nadic anhydride.   37. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer (i) comprises 2,6-naphthalenedicarboxylic acid, 1,8 dihydroxy naphthalene, and/or hydrogenated 1,8 dihydroxy naphthalene, and/or esters and/or anhydrides of all the aforementioned acids.   38. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer (ii) comprises hydrogenated bisphenol A, and/or 2-(2-carboxyphenyl)-benzoic acid, and/or esters and/or anhydrides of all the aforementioned acids.   39. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer (iii) comprises 2,5 furandicarboxylic acid, and esters and anhydrides of all the aforementioned acids.   40. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer (iv) comprises isosorbide, and/or isomannide.   41. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer (v) comprises tricyclodecane dimethanol, tricyclodecane diol, and/or tricyclocdecane polycarboxylic acid, and/or esters and/or anhydrides of all the aforementioned acids.   42. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer (vi) comprises nadic methyl acid, nadic acid, and/or chlorendic anhydride, and/or esters and/or anhydrides/acids of all the aforementioned acids/anhydrides.   43. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer (vii) comprises cyclohexane dimethanol, cyclohexane diol, 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, dimethyl-1,4-cyclochexane dicarboxylate, isophthalic acid, and/or terephthalic acid and/or esters and/or anhydrides of all the aforementioned acids.   44. A resin, coating composition or packaging according to any preceding aspect, wherein (viii) comprises neopentyl glycol.   45. A resin, coating composition or packaging according to any preceding aspect, wherein the Tg enhancing monomer (ix) comprises 3,9-Bis(1,1-dialkyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, wherein alkyl is methyl, ethyl or propyl, suitably monomer (ix) is 3,9-Bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane.   46. A resin, coating composition or packaging according to any preceding aspect, wherein the polyol and polyacid components together comprise at least 10 mole % of a Tg enhancing monomer (i) to (ix) wherein the total mole % of the combined polyol and polyacid components is 100 mole %.   47. A resin, coating composition or packaging according to any preceding aspect, wherein the polyol and polyacid components together comprise at least 20 mole % of a Tg enhancing monomer (i) to (ix) wherein the total mole % of the combined polyol and polyacid components is 100 mole %.   48. A resin, coating composition or packaging according to any preceding aspect, wherein the polyol and polyacid components together comprise at least 30 mole % of a Tg enhancing monomer (i) to (ix) wherein the total mole % of the combined polyol and polyacid components is 100 mole %.   49. A resin, coating composition or packaging according to any preceding aspect, wherein the polyol and polyacid components together comprise at least 40 mole % of a Tg enhancing monomer (i) to (ix) wherein the total mole % of the combined polyol and polyacid components is 100 mole %.   50. A resin, coating composition or packaging according to any preceding aspect, wherein the polyol and polyacid components together comprise at least 50 mole % of a Tg enhancing monomer (i) to (ix) wherein the total mole % of the combined polyol and polyacid components is 100 mole %.   51. A resin, coating composition or packaging according to any preceding aspect, wherein the polyol and polyacid components together comprise at least 10 mole % of a Tg enhancing monomer (i) to (v) and/or (ix) wherein the total mole % of the combined polyol and polyacid components is 100 mole %, such as at least 20 mole %, at least 30 mole %, at least 40 mole % or at least 50 mole %.   52. A resin, coating composition or packaging according to any preceding aspect, wherein the polyol and polyacid components together comprise at least 15 mole % of a Tg enhancing monomer (vi) and/or (viii), and/or (vii) when aromatic, wherein the total mole % of the combined polyol and polyacid components is 100 mole %, such as at least 20 mole %, at least 30 mole %, at least 40 mole % or at least 50 mole %.   53. A resin, coating composition or packaging according to any preceding aspect, wherein the polyol and polyacid components together comprise at least 20 mole % of a Tg enhancing monomer (vii) when cycloalkyl, wherein the total mole % of the combined polyol and polyacid components is 100 mole %, such as at least 30 mole %, at least 40 mole % or at least 50 mole %.   54. A resin, coating composition or packaging according to any preceding aspect, wherein the polyacid component comprises, either in addition to a Tg enhancing monomer polyacid (i) to (x) or in the absence of a Tg enhancing monomer polyacid (i) to (x): maleic acid; fumaric acid; itaconic acid; adipic acid; azelaic acid; succinic acid; sebacic acid; glutaric acid; decanoic diacid; dodecanoic diacid; trimellitic acid; naphthalene tetracarboxylic acid; cyclohexanetetra carboxylic acid; cyclobutane tetracarboxylic; and/or a monomer having an aliphatic group containing at least 15 carbon atoms; and/or esters and/or anhydrides of all the aforementioned acids and combinations thereof.   55. A resin, coating composition or packaging according to any preceding aspect, wherein the polyacid component comprises: dimethyl terephthalate, isophthalic acid, and/or hexahydrophthalic anhydride, cyclohexane 1,4-dicarboxylic acid.   56. A resin, coating composition or packaging according to any preceding aspect, wherein the polyacid component comprises: isophthalic acid, and/or hexahydrophthalic anhydride.   57. A resin, coating composition or packaging according to any preceding aspect, wherein the polyacid component comprises: dimethyl terephthalate, hexahydrophthalic anhydride, cyclohexane 1,4-dicarboxylic acid and/or a monomer having an aliphatic group containing at least 15 carbon atoms, such as a dimer fatty acid, suitably a dimer fatty acid comprising 18 to 50 carbon atoms, such as a dimer fatty acid comprising 20 to 46 carbon atoms, or a dimer fatty acid comprising from 22 to 44 carbon atoms, for example a dimer fatty acid comprising from 24 to 42 carbon atoms, a dimer fatty acid comprising from 26 to 40 carbon atoms, a dimer fatty acid comprising from 28 to 38 carbon atoms, or a dimer fatty acid comprising from 30 to 38 carbon atoms.   58. A resin, coating composition or packaging according to any preceding aspect, wherein the polyacid component comprises isophthalic acid, hexahydrophthalic anhydride, cyclohexane 1,4-dicarboxylic acid and/or a monomer having an aliphatic group containing at least 15 carbon atoms, such as a dimer fatty acid, suitably a dimer fatty acid comprising 18 to 50 carbon atoms, such as a dimer fatty acid comprising 20 to 46 carbon atoms, or a dimer fatty acid comprising from 22 to 44 carbon atoms, for example a dimer fatty acid comprising from 24 to 42 carbon atoms, a dimer fatty acid comprising from 26 to 40 carbon atoms, a dimer fatty acid comprising from 28 to 38 carbon atoms, or a dimer fatty acid comprising from 30 to 38 carbon atoms.   59. A resin, coating composition or packaging according to any preceding aspect, wherein the polyol component comprises, either in addition to a Tg enhancing monomer polyol (i) to (x) or in the absence of a Tg enhancing monomer polyol (i) to (x): alkylene glycols, such as ethylene glycol; propylene glycol; diethylene glycol; dipropylene glycol; triethylene glycol; tripropylene glycol; hexylene glycol; polyethylene glycol; and/or polypropylene glycol; cyclohexanediol; propanediols including 1,2-propanediol; 1,3-propanediol; butyl ethyl propanediol; 2-methyl-1,3-propanediol; and/or 2-ethyl-2-butyl-1,3-propanediol; butanediols including 1,4-butanediol; 1,3-butanediol; and/or 2-ethyl-1,4-butanediol; pentanediols including trimethyl pentanediol and/or 2-methylpentanediol; cyclohexanedimethanol; hexanediols including 1,6-hexanediol; caprolactonediol (for example, the reaction product of epsilon-capro lactone and ethylene glycol); hydroxyalkylated bisphenols; polyether glycols, for example, poly(oxytetramethylene) glycol; trimethylol propane; pentaerythritol; di-pentaerythritol; trimethylol ethane; trimethylol butane; dimethylol cyclohexane; bio-derived polyols such as glycerol, sorbitol; and/or a monomer having an aliphatic group containing at least 15 carbon atoms; or combinations thereof.   60. A resin, coating composition or packaging according to any preceding aspect, wherein the polyol component comprises a Tg enhancing monomer (i) to (x) in combination with 2-methy-1,3-propanediol, suitably cyclohexanedimethanol in combination with a different Tg enhancing monomer (i) to (ix) and 2-methy-1,3-propanediol.   61. A resin, coating composition or packaging according to any preceding aspect, wherein the polyol component comprises a polyol having at least three hydroxyl groups, such as trimethylol propane; pentaerythritol; di-pentaerythritol; trimethylol ethane; trimethylol butane; and/or bio-derived polyols such as glycerol and/or sorbitol, suitably trimethylol propane; trimethylol ethane; and/or trimethylol butane, for example trimethylol propane.   62. A resin, coating composition or packaging according to any preceding aspect, wherein the polyol having at least three hydroxyl groups is present as a proportion of the dry weight of the polyol component in an amount of from 0.1 to 10 wt %, such as from 0.5 to 8 wt % or from 0.7 to 6 wt %, for example from 0.8 to 5 wt % or from 0.9 to 4 wt %, suitably from 1 to 3 wt % or from 1 to 2 wt %.   63. A resin, coating composition or packaging according to any preceding aspect, wherein the polyol component comprises a Tg enhancing monomer (i) to (x) in combination with 2-methy-1,3-propanediol, and/or trimethylolpropane, suitably cyclohexanedimethanol in combination with a different Tg enhancing monomer (i) to (x), 2-methyl-1,3-propanediol and trimethylolpropane.   64. A resin, coating composition or packaging according to any preceding aspect, wherein the aliphatic group of the aliphatic group-containing monomer comprises from 18 to 50 carbon atoms, such as from 20 to 46 carbon atoms, from 22 to 44 carbon atoms, from 24 to 42 carbon atoms, from 26 to 40 carbon atoms.   65. A resin, coating composition or packaging according to any preceding aspect, wherein the aliphatic group of the aliphatic group-containing monomer comprises from 28 to 38 carbon atoms, or from 30 to 38 carbon atoms.   66. A resin, coating composition or packaging according to any preceding aspect, wherein the aliphatic group of the aliphatic group-containing monomer is branched and/or comprises a cyclic group.   67. A resin, coating composition or packaging according to any preceding aspect, wherein aliphatic group-containing monomer is a diacid.   68. A resin, coating composition or packaging according to any preceding aspect, wherein the aliphatic group-containing monomer is a dimer fatty acid.   69. A resin, coating composition or packaging according to any preceding aspect, wherein the aliphatic group-containing monomer is the dimerisation product of erucic acid, linolenic acid, linoleic acid, and/or oleic acid.   70. A resin, coating composition or packaging according to any preceding aspect, wherein the polyacid component and/or the polyol component comprises a sulfonated monomer.   71. A resin, coating composition or packaging according to any preceding aspect, wherein the sulfonated monomer comprises: 5-(sodiosulfo)-isophthalic acid, dimethyl 5-(sodiosulfo)isophalate, 5-(lithiosulfo)isophthalic acid, and/or bis(2-hydroxyethyl)-5-(sodiosulfo)isophthalate.   72. A resin, coating composition or packaging according to any preceding aspect, wherein the polyester material comprises an Mn from 1,000 Daltons (Da=g/mole) to 15,000 Da, suitably from 2,000 Da to 10,000 Da, such as from 3,000 Da to 8,000 Da, or even from 4,000 to 7,000 Da.   73. A resin, coating composition or packaging according to any preceding aspect, wherein the polyester material has a gross OHV of from 0 to 120 mg KOH/g.   74. A resin, coating composition or packaging according to any preceding aspect, wherein the polyester material has an AV from 0 to 20 KOH/g, suitably from 0 to 10 mg KOH/g, such as less than 5 or even less than 3.   75. A resin, coating composition or packaging according to any preceding aspect, wherein the polyester material has a Mn of from 3,000 to 8,000 Da, and an acid value of from 0 to 10 mg KOH/g.   76. A resin, coating composition or packaging according to any preceding aspect, wherein the polyester material has a Mn of from 4,000 to 7,000 Da, and an acid value of less than 5 mg KOH/g.   77. A resin, coating composition or packaging according to any preceding aspect, wherein the acrylic polyester resin is formed from the polyester material and an acrylic modification polymer in a weight ratio of from 95 wt % to 55 wt % polyester material to from 45 wt % to 5 wt % acrylic modification polymer, such as from 90 wt % to 55 wt % polyester material to from 45 wt % to 10 wt % acrylic modification polymer, or from 90 wt % to 55 wt % polyester material to from 45 wt % to 10 wt % acrylic modification polymer, such as a weight ratio of from 90 wt % to 60 wt % polyester material to from 40 wt % to 10 wt % acrylic modification polymer, such as a weight ratio of from 85 wt % to 65 wt % polyester material to from 35 wt % to 15 wt % acrylic modification polymer.   78. A resin, coating composition or packaging according to any preceding aspect, wherein the acrylic polyester resin is formed from the polyester material and an acrylic modification polymer in a weight ratio of from 85 wt % to 55 wt % polyester material to from 45 wt % to 15 wt % acrylic modification polymer.   79. A resin, coating composition or packaging according to any preceding aspect, wherein an acrylic modification polymer is polymerized in the presence of the polyester material to form an acrylic modified polyester resin.   80. A resin, coating composition or packaging according to any preceding aspect, wherein the acrylic modification polymer is formed from: methyl(meth)acrylate, ethyl(meth)acrylate, butyl (meth)acrylate, isobornyl (meth)acrylate, hydroxyethyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, (meth)acrylic acid; cyclohexyl (meth)acrylate, allyl (meth)acrylate, dimethylamino ethyl methacrylate, butylamino ethyl (meth)acrylate, and/or HEMA phosphate (such as ethylene glycol methacrylate phosphate).   81. A resin, coating composition or packaging according to any preceding aspect, wherein the acrylic monomers comprise a hydroxyl functional monomer, such as hydroxyethyl (meth)acrylate.   82. A resin, coating composition or packaging according to any preceding aspect, wherein the hydroxyl functional monomer is present by dry weight of the acrylic modification polymer in an amount of from 5 to 40 wt %, such as from 5 to 30 wt % or from 10 to 20 wt %.   83. A resin, coating composition or packaging according to any preceding aspect, wherein the acrylic polyester resin, which may be an acrylic modified polyester resin, is present in the aqueous coating composition or powder coating composition in an amount of from 50 to 99 wt % (based on dry weight of the coating composition), suitably, in an amount of from 60 to 95 wt % (based on dry weight of the coating composition).   84. A resin, coating composition or packaging according to any preceding aspect, wherein the acrylic monomers comprise a ratio of methacrylate monomers to acrylate monomers of at least 1:1, such as at least 2:1 or at least 3:1 or at least 4:1, suitably at least 5:1.   85. A resin, coating composition or packaging according to any preceding aspect, wherein the polyester material, the acrylic polyester resin and/or a coating formed from the coating composition has a Tg of from 25° C. to 200° C.   86. A resin, coating composition or packaging according to any preceding aspect, wherein the polyester material, the acrylic polyester resin and/or a coating formed from the coating composition has a Tg of at least 25°, or at least 30° C., or at least 35° C., such as at least 40° C.   87. A resin, coating composition or packaging according to any preceding aspect, wherein the polyester material, the acrylic polyester resin and/or a coating formed from the coating composition has a Tg of at least 45° C., or at least 50° C. such as at least 55° C. or at least 60° C., or at least 65° C.   88. A resin, coating composition or packaging according to any preceding aspect, wherein the polyester material, the acrylic polyester resin and/or a coating formed from the coating composition has a Tg of or at least 70° C., or at least 75° C., or at least 80° C.   89. A resin, coating composition or packaging according to any preceding aspect, wherein the polyester material, the acrylic polyester resin and/or a coating formed from the coating composition has a Tg of up to 200° C. such as up to 150° C., or up to 120° C., or up to 110° C., or up to 105° C.   90. A resin, coating composition or packaging according to any preceding aspect, wherein the acrylic polyester resin has a Mn from 1,000 Daltons (Da=g/mole) to 15,000 Da, suitably from 2,000 Da to 10,000 Da, such as from 3,000 Da to 8,000 Da, or even from 4,000 to 7,000 Da.   91. A resin, coating composition or packaging according to any preceding aspect, wherein the acrylic polyester resin has a gross OHV from 0 to 120 mg KOH/g.   92. A resin, coating composition or packaging according to any preceding aspect, wherein the acrylic polyester resin has an AV from 10 to 80 KOH/g, such as from 20 to 70 mg KOH/g, suitably from 30 to 60 mg KOH/g.   93. A resin, coating composition or packaging according to any preceding aspect, wherein the acrylic polyester resin, which may be an acrylic modified polyester resin, has a Mn of 3,000 to 9,000 Da, and an AV of from 20 to 70 mg KOH/g.   94. A resin, coating composition or packaging according to any preceding aspect, wherein the acrylic polyester resin, which may be an acrylic modified polyester resin, has a Mn of 3,500 to 8,000 Da, and an AV of from 30 to 60 mg KOH/g.   95. A coating composition or packaging according to any preceding aspect, wherein the wherein the crosslinking material comprises material according to formula (XIII)   

     
       
         
         
             
             
         
       
         
         
           
             wherein R 1  is hydrogen, alkyl (such as C 1  to C 20  alkyl), aryl (such as C 4  to C 24  aryl), aralkyl (such as C 5  to C 25  aralkyl), or —NR 6 R 7 ; 
             R 2  to R 7  are each independently hydrogen, alkyl (such as C 1  to C 20  alkyl), aryl (such as C 4  to C 24  aryl), aralkyl (such as C 5  to C 25  aralkyl) or —CHR 8 OR 9 ; 
             wherein R 8  and R 9  are each independently hydrogen, alkyl (such as C 1  to C 20  alkyl), aryl (such as C 4  to C 24  aryl), aralkyl (such as C 5  to C 25  aralkyl), alkoxyalkyl (such as C 2  to C 40  alkoxyalkyl) or an alkaryl (such as C 5  to C 25  alkaryl); 
             wherein at least one of R 2  to R 5 , or R 2  to R 7  when present, is —CHR 8 OR 9 , suitably all of R 2  to R 5 , or R 2  to R 7  when present, are —CHR 8 OR 9 . 
           
         
         96. A coating composition or packaging according to any preceding aspect, wherein in the crosslinking material according to formula (XIII), R 1  is C 1  to C 20  alkyl, C 4  to C 24  aryl, C 5  to C 25  aralkyl, or —NR 6 R 7 ; such as C 4  to C 24  aryl or C 5  to C 25  aralkyl, or C 4  to C 24  aryl, suitably C 4  to C 12  aryl, such as C 6  aryl. 
         97. A coating composition or packaging according to any preceding aspect, wherein in the crosslinking material according to formula (XIII), R 1  is —NR 6 R 7 . 
         98. A coating composition or packaging according to any preceding aspect, wherein in the crosslinking material according to formula (XIII), R 2  to R 7 , when present as applicable, are each be independently hydrogen, C 1  to C 20  alkyl, C 4  to C 24  aryl or —CHR 8 OR 9 , such as hydrogen, C 1  to C 20  alkyl or —CHR 8 OR 9 , such as hydrogen, C 1  to C 10  alkyl or —CHR 8 OR 9 ; such as C 1  to C 5  alkyl or —CHR 8 OR 9 , suitably —CHR 8 OR 9 . 
         99. A coating composition or packaging according to any preceding aspect, wherein in the crosslinking material according to formula (XIII), R 2  to R 7 , when present as applicable, are each be independently hydrogen, C 1  to C 20  alkyl, C 4  to C 24  aryl or —CHR 8 OR 9 , such as hydrogen, C 1  to C 20  alkyl or —CHR 8 OR 9 , such as hydrogen, C 1  to C 10  alkyl or —CHR 8 OR 9 ; such as C 1  to C 5  alkyl or —CHR 8 OR 9 , suitably —CHR 8 OR 9 , and R 8  is independently hydrogen, C 1  to C 20  alkyl, C 4  to C 24  aryl, C 5  to C 25  aralkyl, alkoxyalkyl C 2  to C 40  alkoxyalkyl or C 5  to C 25  alkaryl, such as hydrogen, C 1  to C 20  alkyl, suitably hydrogen; and R 9  is hydrogen, C 1  to C 20  alkyl, C 4  to C 24  aryl, C 5  to C 25  aralkyl, alkoxyalkyl C 2  to C 40  alkoxyalkyl or C 5  to C 25  alkaryl; such as hydrogen, C 1  to C 20  alkyl; suitably C 1  to C 20  alkyl, or C 1  to C 10  alkyl, or C 1  to C 5  alkyl, such as C 1  or C 2  alkyl. 
         100. A coating composition or packaging according to any preceding aspect, wherein the crosslinking material according to formula (XIII) is formed by reacting a triazine such as melamine or benzoguanamine with formaldehyde. 
         101. A coating composition or packaging according to any preceding aspect, wherein the crosslinking material according to formula (XIII) comprises melamine or derivatives thereof, such as butylated and/or methylated melamine; and benzoguanamine or derivatives thereof, such as butylated and/or methylated benzoguanamine. 
         102. A coating composition or packaging according to any preceding aspect, wherein the crosslinking material comprises a phenolic resin, benzoguanamine and/or melamine. 
         103. A coating composition or packaging according to any preceding aspect, wherein the crosslinking material comprises benzoguanamine. 
         104. A coating composition or packaging according to any preceding aspect, wherein the crosslinking material according to formula (XIII) forms at least 50 wt % of the crosslinking material of the coating composition, such as at least 60 wt %, at least 70 wt %, at least 80 wt %, at least 90 wt %, at least 95 wt % or at least 98 wt % such as at least 99 wt % of the crosslinking material of the coating composition. 
         105. A coating composition or packaging according to any preceding aspect, wherein the crosslinking material is substantially formed of crosslinking material according to formula (XIII). 
         106. A coating composition or packaging according to any preceding aspect, wherein the aqueous coating composition or powder coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF) and derivatives thereof. 
         107. A coating composition or packaging according to any preceding aspect wherein the aqueous coating composition or powder coating composition is substantially free of styrene. 
         108. A coating composition or packaging according to any preceding aspect wherein the aqueous coating composition or powder coating composition is substantially free of formaldehyde. 
         109. A coating composition or packaging according to any preceding aspect, wherein the aqueous coating composition or powder coating composition further comprises an adhesion promoter. 
         110. A coating composition or packaging according to any preceding aspect, wherein the adhesion promotor comprises an acidic polyester material. 
         111. A coating composition or packaging according to any preceding aspect, wherein the acidic polyester generally comprises the reaction product of:
       (a) a polyester having an Mn of 2000 to 10,000, a hydroxyl number of 20 to 75, and an acid value of 15 to 25; the polyester being a polycondensate of:
           (i) a polyol component comprising a mixture of diols and triols,   (ii) a polyacid component comprising an alpha, beta-ethylenically unsaturated polycarboxylic acid, and   
           (b) a phosphorus acid.   
     
         112. A coating composition according to any preceding aspect, wherein the coating composition has a solids content of from 10 to 60% by weight of the coating composition, such as from 15 to 50 wt % or suitably from 20 to 40 wt %. 
         113. A packaging container according to any preceding aspect, wherein the packaging comprises a food or beverage can or aerosol can. 
         114. A method of forming an acrylic modified polyester resin, the method comprising polymerizing an acrylic modification polymer in the presence of a polyester material, the polyester material being obtainable by polymerizing
       i) a polyacid component, with   ii) a polyol component,   wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   (x) an aliphatic polyacid or polyol monomer wherein the monomer comprises a tetracyclic hydrocarbon ring structure;   wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said functionality, and wherein the acrylic polyester resin has a Tg of at least 25° C.   
     
         115. A method of preparing an aqueous coating composition, the method comprising dispersing an acrylic modified polyester resin and a crosslinking material in an aqueous medium, the acrylic modified polyester resin being obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
       i) a polyacid component, with   ii) a polyol component,   wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid orpolyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   (x) an aliphatic polyacid or polyol monomer wherein the monomer comprises a tetracyclic hydrocarbon ring structure;   wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said functionality, and wherein a coating formed from the coating composition has a Tg of at least 25° C.   
     
         116. A method of coating at least a portion of a metal packaging container, the method comprising applying an aqueous coating composition or powder coating composition to a metal packaging composition, the aqueous coating composition or powder coating composition comprising an acrylic modified polyester resin and a crosslinking material, the acrylic modified polyester resin being obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
       i) a polyacid component, with   ii) a polyol component,   wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   (x) an aliphatic polyacid or polyol monomer wherein the monomer comprises a tetracyclic hydrocarbon ring structure;   wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said functionality, and curing the aqueous coating composition or powder coating composition to form a coating, and wherein the coating has a Tg of at least 25° C.   
     
         117. A method of coating at least a portion of a packaging, the method comprising applying an aqueous coating composition or powder coating composition to a packaging, the aqueous coating composition or powder coating composition comprising an acrylic modified polyester resin and a crosslinking material, the acrylic modified polyester resin being obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing:
       i) a polyacid component, with   ii) a polyol component,   wherein the polyacid component and/or the polyol component comprises a Tg enhancing monomer comprising:   (i) an optionally substituted naphthalene group-containing polyacid or polyol, or hydrogenated derivative thereof;   (ii) a polyacid or polyol comprising two optionally substituted 5 or 6 membered cyclic groups, wherein the cyclic groups do not share an atom, and wherein the cyclic groups are directly bonded or are separated by one carbon atom;   (iii) an optionally substituted furan group-containing polyacid or polyol;   (iv) an optionally substituted fused bicyclic group-containing polyacid or polyol, wherein each ring is a five membered ring and in which one or both rings may comprise a heteroatom in the ring;   (v) an optionally substituted bridged tricyclodecane group-containing polyacid or polyol;   (vi) an optionally substituted bridged norbornene-group containing polyacid or polyol, or hydrogenated derivative thereof;   (vii) an optionally substituted 5 or 6 membered cycloalkyl or aromatic group-containing polyacid or polyol;   (viii) a branched alkyl group-containing polyacid or polyol monomer wherein the monomer comprises at least one quaternary carbon atom and is formed of from 5 to 10 carbon atoms, and wherein the carbon atoms bonded to the acid or hydroxyl groups are primary carbon atoms; and/or   (ix) an optionally substituted tetraoxaspiro[5.5]undecane-group containing polyacid or polyol;   (x) an aliphatic polyacid or polyol monomer wherein the monomer comprises a tetracyclic hydrocarbon ring structure;   wherein one of the polyacid component or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said functionality, and curing the aqueous coating composition or powder coating composition to form a coating, and wherein the coating has a Tg of at least 25° C.   
     
         118. A packaging or method according to any preceding aspect, wherein the packaging is metal packaging, such as a metal can.