Patent GB-1107321-A (GB)
Title: Acrylic coating compositions
Inventor: FRY JOHN SEDGWICK
IPC: C09D125/08
Filed: 1965-03-02
Abstract: Coating compositions comprise the following components: (1) an interpolymer of (a) 0-89% by weight of a monovinyl aromatic compound having 8-12 carbon atoms; (b) 10-90% by weight of a compound selected from alkyl acrylates having 4-15 carbon atoms, alkyl methacrylates having 5-16 carbon atoms, cyanoethyl, cyanopropyl or cyanobutyl acrylate, acrylamide and its N,N-dialkyl derivatives wherein each alkyl group has 1-6 carbon atoms, and hydroxyalkyl acrylates and methacrylates wherein the alkyl group has 1-4 carbon atoms; (c) 0-50% of a compound selected from a ,b -olefinically unsaturated nitriles having 3-9 carbon atoms, vinyl acetate and vinyl or vinylidene chloride or fluoride; and (d) 1-20% of an a ,b -olefinically unsaturated carboxylic acid having up to 10 carbon atoms; said interpolymer having a reduced viscosity of 0.1 to 0.8 (at 25 DEG  C. in tetrahydrofuran) and a Tg of at least 25 DEG  C.; (2) 1-70%, based on the weight of the interpolymer, of a reactive polyol (as defined) having a hydroxyl number of 20-1800; and (3) 5-35%, based on the weight of the interpolymer, of a thermosetting condensation product of formaldehyde with a phenol, urea or triazine compound; said components being dissolved in water or an organic solvent, or being in the form of a liquid high solids composition (as defined).  For the aqueous compositions the interpolymer is reacted with ammonia to form the water-soluble ammonium salt.  In a modification, component (d) of polymer component (1) is replaced by hydroxyethyl or hydroxypropyl acrylate or methacrylate, the monoallyl ether of trimethylolpropane, allyl alcohol, acrylamide or methacrylamide, the composition being in liquid high solids form.  Component 1(a) may be, for example, styrene or a derivative thereof or vinyl naphthalene; suitable nitriles for component 1(c) include acrylonitrile, a -chloroacrylonitrile and a -trifluoromethyl acrylonitrile; and specified acids for component 1(d) are acrylic, methacrylic, crotonic, cinnamic, atropic, a -chloroacrylic, a -fluoroacrylic, maleic, fumaric and itaconic acids, and monoisopropyl maleate and mono-n-butyl fumarate.  Suitable polyols include hydroxy-terminated polyesters and polyesterethers; polytetramethylene glycols; adducts of alkylene oxides with polyhydroxy compounds (e.g. polyoxypropylene diols and triols and polyoxyethylene diols), amines, ternary condensation products of aromatic amines/phenols/aldehydes, or with phosphorus oxy acids or hydroxyl-terminated esters thereof; and low molecular weight diols.  Component (3) may be, for example, trimethylol phenol, butylated melamine - formaldehyde resin, dimethylol ethylene urea - formaldehyde resin, urea - formaldehyde resin, benzoguanamine - formaldehyde resin, and preferably hexamethylol melamine hexamethyl ether.  If desired, the composition may include a catalyst to assist the thermosetting of component (3), e.g. p-toluenesulphonic acid or the methyl ester thereof.  Solvents exemplified (non-aqueous) comprise dioxane, ethylene glycol monoethyl ether, toluene, xylene or ethyl alcohol.  Optional ingredients include plasticizers, e.g. tricresyl phosphate and butyl benzyl phthalate, and pigments, e.g. titanium dioxide.  The compositions provide heat-curable films.  In examples, the interpolymers are prepared by polymerizing the corresponding monomers in dioxane or xylene in the presence of t-dodecyl mercaptan using benzoyl peroxide catalyst.ALSO:Coating compositions comprise (1) an acrylic interpolymer as defined in Specification 1,105,561, (2) 1-70% by weight of the interpolymer of a reactive polyol having a hydroxyl number of from 20 to 1800 and (3) 5-35% by weight of the interpolymer of a thermosetting resin formed by condensation of formaldehyde with a phenol, urea or triazine compound; said components being dissolved in water or an organic solvent, or being in the form of a liquid high solids composition (as defined).  For the aqueous compositions, the interpolymer is converted to the ammonium salt form.  In a modification the acid constituent of the interpolymer is replaced by hydroxy ethyl or hydroxy propyl acrylate or methacrylate, the monoallyl ether of trimethylolpropane, alkyl alcohol, acrylamide or methacrylamide, the composition being in liquid high solids form. Suitable polyols (2) include hydroxy-terminated polyesters and polyester-ethers, alkylene oxide adducts with polyhydroxy compounds, amines, hydroxy-terminated phosphorus esters &c., e.g. polyoxypropylene diols and triols and polyoxyethylene diols, and low molecular weight diols.  Component (3) may be, for example, trimethylol phenol, butylated melamine-formaldehyde resin, dimethylol ethyleneurea resin, urea-formaldehyde resin, benzoguanamine-formaldehyde resin and, preferably, hexamethylol melamine hexamethyl ether.  The composition may include a catalyst, e.g. p-toluenesulphonic acid or its methyl ester, to assist the thermosetting of component (3). Exemplified non-aqueous solvents comprise dioxane, ethylene glycol monoethyl ether, toluene, xylene or ethyl alcohol. Optional ingredients include plasticisers, e.g. tricresyl phosphate or butyl benzyl phthalate, and pigments, e.g. titanium dioxide.  The coatings obtained with the compositions can be cured by baking.  In Examples, coatings are applied to steel panels by dip-coating, flow-coating, melt extrusion and drawdown blade methods.