Patent Description:
Mixed two-component curable polyurethane adhesive systems can be applied using a number of methods. Viscosity of the newly mixed adhesive will be a composite of the viscosity of each component. Each application method will require the newly mixed adhesive to be within a defined viscosity range for successful use; below this range the applied mixture will spread and run and above this range the mixed adhesive may not apply evenly or at all. Two-component curable polyurethane systems have traditionally relied on modification of the polyol component to effectively increase the viscosity or "thicken" mixtures of the two components. There currently are very few options available to effectively thicken the polyisocyanate component. The most common method of increasing viscosity of the polyisocyanate component is to make an isocyanate functional pre-polymer, but prepolymer production requires special reaction processes and equipment and prepolymer use may raise TSCA (Toxic Substances Control Act) or other regulatory concerns. Production of a pre-polymer can introduce repeatability issues as well. Other common techniques for increasing viscosity of the polyisocyanate component include incorporating materials like silica into the polyisocyanate component. However, silica thixotropes when mixed with polyisocyanates introduce shear thinning properties, can react with the isocyanate, and lead to de-gassing issues.

<CIT> discloses a polyurethane elastomer based on a two-component curable composition comprising diphenylmethane diisocyanate (MDI), polyvinyl acetate (PVA) and polytetramethylene ether diol.

<CIT> discloses a two-component curable adhesive composition based on a polyisocyanate and polyvinyl acetate, further comprising BPA/PPO ether and vinyl-functional PPO and polyol cyclic ether.

"<NPL> discloses curable two-component coating systems based on polyisocyanates. Specifically, polyvinyl acetate polymer used as modifier in an amount of <NUM> to <NUM> wt-% can be used to improve the leveling properties of the coating.

<CIT> discloses a two-component polyurethane adhesive composition of which the first component comprises a MDI-based NCO-prepolymer and the second component comprises a polyester polyol.

MY <NUM> A discloses a two-component adhesive using an adhesive base derived from b) PVAc/PVC copolymer and <NUM> wt. -% of a hardener derived from MDI.

<CIT> discloses a two-component adhesive comprising a polylactide or polylactide/polyether polyol, and an NCO-prepolymer based on MDI, optionally comprising an ethylene vinyl acetate thermoplastic polymer.

<CIT> discloses a two-component curable adhesive prepared from an NCO-prepolymer based on XDI-based polyisocyanate and a polyester polyol.

<CIT> discloses a two-component curable composition based on a plasticised composition comprising a polyol and an ethylene vinyl acetate copolymer and MDI.

Until now, there have been few efforts to determine the effect on physical properties of mixed two-component adhesives having polyvinyl acetate polymers and copolymers blended in significant amounts with the polyisocyanate component of these two-component adhesives.

The inventors have unexpectedly discovered that polyvinyl acetate homopolymer is not only compatible but form a homogeneous mixture with the polyisocyanate that remained stable indefinitely. Furthermore, the vinyl acetate homopolymer surprisingly increased the viscosity of the polyisocyanate component of two-component curable polymer systems, while maintaining a Newtonian viscosity. Two-component polyurethane systems incorporating the vinyl acetate homopolymer in the polyisocyanate component can be used for such applications as potting, coatings, and adhesives, for instance. Due to the Newtonian viscosity characteristics, such systems are particularly suitable for potting compounds, where the Newtonian viscosity imparts a "self-leveling" property. The adhesion of such systems, if used as adhesives, was not significantly degraded beyond the expected effect of dilution of the polyisocyanate component due to the addition of the vinyl acetate homopolymer.

The invention relates to a two-component curable composition as defined in claim <NUM>.

In one embodiment the homogeneous polyisocyanate component comprising a) and b) has a viscosity measured on a DV-III Brookfield Viscometer using RV spindle <NUM>, at either <NUM> RPM or <NUM> RPM, conditioned for at least <NUM> hours at <NUM> with RV Spindle <NUM> of at least <NUM> mPa·sec.

In certain embodiments, the viscosity of the mixture of a) and b) was <NUM> times higher (under the same conditions) than the viscosity of a) alone.

In other embodiments the viscosity of the composition a) and b) remained generally Newtonian even with the significant increase in viscosity.

In one embodiment, the two-component curable composition has a viscosity of at least <NUM> mPa·sec measured on a Brookfield viscometer at <NUM> RPM with spindle <NUM> at <NUM>.

The disclosure is also directed to the reaction product of this mixture of A) and B).

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art. As used herein for each of the various embodiments, the following definitions apply.

"Alkyl" or "alkane" refers to a hydrocarbon chain or group containing only single bonds between the chain carbon atoms. The alkane can be a straight hydrocarbon chain or a branched hydrocarbon group. The alkane can be cyclic. The alkane can contain <NUM> to <NUM> carbon atoms, advantageously <NUM> to <NUM> carbon atoms and more advantageously <NUM> to <NUM> carbon atoms. In some embodiments the alkane can be substituted. Exemplary alkanes include methyl, ethyl, n-propyl, isopropyl, isobutyl, n-butyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl and decyl.

"Alkenyl" or "alkene" refers to a hydrocarbon chain or group containing one or more double bonds between the chain carbon atoms. The alkenyl can be a straight hydrocarbon chain or a branched hydrocarbon group. The alkene can be cyclic. The alkene can contain <NUM> to <NUM> carbon atoms, advantageously <NUM> to <NUM> carbon atoms and more advantageously <NUM> to <NUM> carbon atoms. The alkene can be an allyl group. The alkene can contain one or more double bonds that are conjugated. In some embodiments the alkene can be substituted.

"Alkoxy" refers to the structure -OR, wherein R is hydrocarbyl.

"Alkyne" or "alkynyl" refers to a hydrocarbon chain or group containing one or more triple bonds between the chain carbon atoms. The alkyne can be a straight hydrocarbon chain or a branched hydrocarbon group. The alkyne can be cyclic. The alkyne can contain <NUM> to <NUM> carbon atoms, advantageously <NUM> to <NUM> carbon atoms and more advantageously <NUM> to <NUM> carbon atoms. The alkyne can contain one or more triple bonds that are conjugated. In some embodiments the alkyne can be substituted.

"Amine" refers to a molecule comprising at least one -NHR group wherein R can be a covalent bond, H, hydrocarbyl or polyether. In some embodiments an amine can comprise a plurality of -NHR groups.

"Aryl" or "Ar" refers to a monocyclic or multicyclic aromatic group. The cyclic rings can be linked by a bond or fused. The aryl can contain from <NUM> to about <NUM> carbon atoms; advantageously <NUM> to <NUM> carbon atoms and in some embodiments <NUM> carbon atoms. Exemplary aryls include phenyl, biphenyl and naphthyl. In some embodiments the aryl is substituted.

"Ester" refers to the structure R-C(O)-O-R' where R and R' are independently selected hydrocarbyl groups with or without heteroatoms. The hydrocarbyl groups can be substituted or unsubstituted.

"Halogen" or "halide" refers to an atom selected from fluorine, chlorine, bromine and iodine.

"Hetero" refers to one or more heteroatoms in a structure. Exemplary heteroatoms are independently selected from N, O and S.

"Heteroaryl" refers to a monocyclic or multicyclic aromatic ring system wherein one or more ring atoms in the structure are heteroatoms. Exemplary heteroatoms are independently selected from N, O and S. The cyclic rings can be linked by a bond or fused. The heteroaryl can contain from <NUM> to about <NUM> carbon atoms; advantageously <NUM> to <NUM> carbon atoms and in some embodiments <NUM> to <NUM> carbon atoms. Exemplary heteroaryls include furyl, imidazolyl, pyrimidinyl, tetrazolyl, thienyl, pyridyl, pyrrolyl, thiazolyl, isothiazolyl, oxazolyl, isoxazolyl, thiazolyl, quinolinyl and isoquinolinyl. In some embodiments the heteroaryl is substituted.

"Hydrocarbyl" refers to a group containing carbon and hydrogen atoms. The hydrocarbyl can be linear, branched, or cyclic group. The hydrocarbyl can be alkyl, alkenyl, alkynyl or aryl. In some embodiments, the hydrocarbyl is substituted.

"(Meth)acrylate" refers to acrylate and methacrylate.

"Molecular weight" refers to weight average molecular weight unless otherwise specified. The number average molecular weight Mn, as well as the weight average molecular weight Mw, is determined according to the present invention by gel permeation chromatography (GPC, also known as SEC) at <NUM> using a styrene standard. This method is known to one skilled in the art. The polydispersity is derived from the average molecular weights Mw and Mn. It is calculated as PD = Mw/Mn. Polydispersity indicates the width of the molecular weight distribution and thus of the different degrees of polymerization of the individual chains in polydisperse polymers. For many polymers and polycondensates, a polydispersity value of about <NUM> applies. Strict monodispersity would exist at a value of <NUM>. A low polydispersity of, for example, less than <NUM> indicates a comparatively narrow molecular weight distribution.

"Oligomer" refers to a defined, small number of repeating monomer units such as <NUM>-<NUM>,<NUM> units, and advantageously <NUM>-<NUM>,<NUM> units which have been polymerized to form a molecule. Oligomers are a subset of the term polymer.

"Polyether" refers to polymers which contain multiple ether groups (each ether group comprising an oxygen atom connected top two hydrocarbyl groups) in the main polymer chain. The repeating unit in the polyether chain can be the same or different. Exemplary polyethers include homopolymers such as polyoxymethylene, polyethylene oxide, polypropylene oxide, polybutylene oxide, polytetrahydrofuran, and copolymers such as polyethylene oxide co propylene oxide), and EO tipped polypropylene oxide.

"Polyester" refers to polymers which contain multiple ester linkages. A polyester can be either linear or branched.

"Polymer" refers to any polymerized product greater in chain length and molecular weight than the oligomer. Polymers can have a degree of polymerization of about <NUM> to about <NUM>. As used herein polymer includes oligomers and polymers.

"Polyol" refers to the molecule comprising two or more -OH groups.

"Substituted" refers to the presence of one or more substituents on a molecule in any possible position. Useful substituents are those groups that do not significantly diminish the disclosed reaction schemes. Exemplary substituents include, for example, H, halogen, (meth)acrylate, epoxy, oxetane, urea, urethane, N<NUM>, NCS, CN, NCO, NO<NUM>, NX<NUM>X<NUM>, OX<NUM>, C(X<NUM>)<NUM>, C(halogen)<NUM>, COOX<NUM>, SX<NUM>, Si(OX<NUM>)iX<NUM><NUM>-i, alkyl, alcohol, alkoxy; wherein X<NUM> and X<NUM> each independently comprise H, alkyl, alkenyl, alkynyl or aryl and i is an integer from <NUM> to <NUM>.

"Thiol" refers to a molecule comprising at least one -SH group. In some embodiments a thiol can comprise a plurality of -SH groups.

This invention relates to two-component or two-part curable polymeric systems. One component of such systems is a polyisocyanate component. The other component of the two-part curable polymeric system comprises a isocyanate reactive material that is capable of reacting with the polyisocyanate material to form a cured polymeric material.

Polyvinyl acetate homopolymers are effective at increasing the viscosity of polyisocyanates and surprisingly effective at increasing viscosity of methylene diphenyl diisocyanate (MDI) based polyisocyanates including but not limited to polymeric MDI, polyisocyanate pre-polymers, modified polyisocyanate pre-polymers, MDI pre-polymers, allophanates of MDI, and modified MDI pre-polymers.

The term "pre-polymer" in this disclosure is understood to mean a material that is synthesized by reacting a stoichiometric excess of a polyisocyanate with a polyisocyanate reactive material, such that the resulting material retains unreacted isocyanate groups.

As an example, for a polyisocyanate reacting with a polyol, "stoichiometric excess" is understood to mean that there are more equivalents of isocyanate functionality from the polyisocyanate compound than equivalents of hydroxyl functionality from the polyol present during reaction to form the pre-polymer. All of the polyol is reacted and the resulting polyisocyanate pre-polymers comprise reactive isocyanate groups. In this disclosure, it is to be understood that the term "polyisocyanate pre-polymer" is applied to any compound made according to the foregoing description, i.e., as long as the compound is made with a stoichiometric excess of isocyanate groups to hydroxyl groups, it is a pre-polymer.

The polyvinyl acetate homopolymer, when blended together to for a homogenous mixture with the polyisocyanate component can effectively increase the viscosity of the polyisocyanate component without introducing shear thinning characteristics and is shown to increase the viscosity of the polyisocyanate as much as <NUM>% compared to polyisocyanate without added polymers.

The polyisocyanate component comprises polymeric diphenylmethanediisocyante (MDI), isocyanate functional pre-polymer, or mixtures thereof. Such components are understood to have on average two or more isocyanate groups. Polymeric MDI is a known commercially available variant of MDI. It is not a pre-polymer but rather "linked" MDI molecules. Polyisocyanate components that are <NUM>% monomeric polyisocyanates do not show the surprising advantages. However, polyisocyanate components comprising up to about <NUM> % by weight monomeric polyisocyanates do show advantageous properties. In some embodiments the polyisocyanate component comprises about <NUM>% or less by weight monomeric polyisocyanates by weight of the polyisocyanate component. Monomeric MDI and its isomers are preferred and may be used exclusively if monomeric polyisocyanates are present in the polyisocyanate component. In some embodiments the polyisocyanate component preferably comprises polymeric MDI, a MDI pre-polymer, monomeric MDI or mixtures thereof.

Some suitable polyisocyanates useful for preparing the isocyanate functional pre-polymers include hydrogenated MDI (HMDI), xylylene diisocyanate (XDI), tetramethyl xylylene diisocyanate (TMXDI), <NUM>,<NUM>'-diphenyl dimethyl-methane diisocyanate, di- and tetraalkylene diphenylmethane diisocyanate, <NUM>,<NUM>'-dibenzyl diisocyanate, <NUM>,<NUM>-phenylene diisocyanate, <NUM>,<NUM>-phenylene diisocyanate, <NUM>-methyl-<NUM>,<NUM>-diisocyanatocyclohexane, <NUM>,<NUM>-diiso-cyanato-<NUM>,<NUM>,<NUM>-trimethyl hexane, <NUM>,<NUM>-diisocyanato-<NUM>,<NUM>,<NUM>-trimethyl hexane, <NUM>-isocyanatomethyl-<NUM>-isocyanato-<NUM>,<NUM>,<NUM>-trimethyl cyclohexane (IPDI), chlorinated and brominated diisocyanates, phosphorus-containing diisocyanates, <NUM>,<NUM>'-diisocyanatophenyl perfluoroethane, tetramethoxybutane-<NUM>,<NUM>-diisocyanate, butane-<NUM>,<NUM>-diisocyanate, hexane-<NUM>,<NUM>-diisocyanate (HDI), dicyclohexylmethane diisocyanate, cyclo-hexane-<NUM>,<NUM>-diisocyanate, ethylene diisocyanate, phthalic acid-bis-isocyanatoethyl ester; diisocyanates containing reactive halogen atoms, such as <NUM>-chloromethylphenyl-<NUM>,<NUM>-diisocyanate, <NUM>-bromomethylphenyl-<NUM>,<NUM>-diisocyanate or <NUM>,<NUM>-bis-chloromethylether4,<NUM>'-diphenyl diisocyanate, trimethyl hexamethylene diisocyanate, <NUM>,<NUM>-diisocyanatobutane, <NUM>,<NUM>-diisocyanatododecane, dimer fatty acid diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, undecane diisocyanate, dodecamethylene diisocyanate, <NUM>,<NUM>,<NUM>-trimethylhexane-<NUM>,<NUM>,<NUM>-trimethylhexamethylene diisocyanate, <NUM>,<NUM>-cyclohexane diisocyanate, <NUM>,<NUM>-cyclohexane diisocyanate, <NUM>,<NUM>- and <NUM>,<NUM>-tetramethyl xylene diisocyanate, isophorone, <NUM>,<NUM>-dicyclohexylmethane, tetramethylxylylene (TMXDI) and lysine ester diisocyanate.

Some suitable polyisocyanates include aromatic polyisocyanates. Aromatic polyisocyanates are characterized by the fact that the isocyanate groups are positioned directly on the benzene ring. Suitable aromatic diisocyanates include <NUM>,<NUM>'-diphenyl methane diisocyanate (MDI) and its isomers, toluene diisocyanate (TDI) and its isomers and naphthalene-<NUM>,<NUM>-diisocyanate (NDI).

Some suitable polyisocyanates include sulfur-containing polyisocyanates that are obtained, for example, by reaction of <NUM> mol hexamethylene diisocyanate with <NUM> mol thiodiglycol or dihydroxydihexyl sulfide.

Aliphatic polyisocyanates with two or more isocyanate functionality formed by biuret linkage, uretdione linkage, allophanate linkage, and/or by trimerization are suitable.

Suitable at least trifunctional polyisocyanates are polyisocyanates formed by trimerization or oligomerization of diisocyanates or by reaction of diisocyanates with polyfunctional compounds containing hydroxyl or amino groups. Isocyanates suitable for the production of trimers are the diisocyanates mentioned above, the trimerization products of HDI, MDI, TDI or IPDI being particularly preferred.

The polyisocyanate component encompasses a single polyisocyanate or the mixture of two or more polyisocyanates.

As used herein an isocyanate reactive compound is a compound containing functional moieties that will react with an isocyanate moiety. The isocyanate reactive component can be a single compound comprising an alcohol moiety, an amine moiety, a thiol moiety, or a compound with a combination of these moieties. The isocyanate reactive component can be a mixture of compounds with each compound comprising one or more moieties independently selected from alcohol, amine, thiol and aminoalcohol.

In one embodiment the isocyanate reactive component can be a polyol. A polyol is understood to be a compound containing more than one OH group in the molecule. A polyol can further have other functionalities on the molecule. The term "polyol" encompasses a single polyol or a mixture of two or more polyols.

Some suitable polyol components include aliphatic alcohols containing <NUM> to <NUM> OH groups per molecule. The OH groups may be both primary and secondary. Some suitable aliphatic alcohols include, for example, ethylene glycol, propylene glycol, butane-<NUM>,<NUM>-diol, pentane-<NUM>,<NUM>-diol, hexane-<NUM>,<NUM>-diol, heptane-<NUM>,<NUM>-diol, octane-<NUM>,<NUM>-diol and higher homologs or isomers thereof which the expert can obtain by extending the hydrocarbon chain by one CH<NUM> group at a time or by introducing branches into the carbon chain. Also suitable are higher alcohols such as, for example, glycerol, trimethylol propane, pentaerythritol and oligomeric ethers of the substances mentioned either individually or in the form of mixtures of two or more of the ethers mentioned with one another.

Some suitable polyols include the reaction products of low molecular weight polyhydric alcohols with alkylene oxides, so-called polyether polyols. The alkylene oxides preferably contain <NUM> to <NUM> carbon atoms. Some reaction products of this type include, for example, the reaction products of ethylene glycol, propylene glycol, the isomeric butane diols, hexane diols or <NUM>,<NUM>'-dihydroxydiphenyl propane with ethylene oxide, propylene oxide or butylene oxide or mixtures of two or more thereof. The reaction products of polyhydric alcohols, such as glycerol, trimethylol ethane or trimethylol propane, pentaerythritol or sugar alcohols or mixtures of two or more thereof, with the alkylene oxides mentioned to form polyether polyols are also suitable. Thus, depending on the desired molecular weight, products of the addition of only a few mol ethylene oxide and/or propylene oxide per mol or of more than one hundred mol ethylene oxide and/or propylene oxide onto low molecular weight polyhydric alcohols may be used. Other polyether polyols are obtainable by condensation of, for example, glycerol or pentaerythritol with elimination of water. Some suitable polyols include those polyols obtainable by polymerization of tetrahydrofuran.

The polyethers are reacted in known manner by reacting the starting compound containing a reactive hydrogen atom with alkylene oxides, for example ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran or epichlorohydrin or mixtures of two or more thereof.

Suitable starting compounds are, for example, water, ethylene glycol, <NUM>,<NUM>- or <NUM>,<NUM>-propylene glycol, <NUM>,<NUM>- or <NUM>,<NUM>-butylene glycol, hexane-<NUM>,<NUM>-diol, octane-<NUM>,<NUM>-diol, neopentyl glycol, <NUM>,<NUM>-hydroxymethyl cyclohexane, <NUM>-methyl propane-<NUM>,<NUM>-diol, glycerol, trimethylol propane, hexane-<NUM>,<NUM>,<NUM>-triol, butane-<NUM>,<NUM>,<NUM>-triol, trimethylol ethane, pentaerythritol, mannitol, sorbitol, methyl glycosides, sugars, phenol, isononylphenol, resorcinol, hydroquinone, <NUM>,<NUM>,<NUM>- or <NUM>,<NUM>,<NUM>-tris-(hydroxyphenyl)-ethane, ammonia, methyl amine, ethylenediamine, tetra- or hexamethylenediamine, triethanolamine, aniline, phenylenediamine, <NUM>,<NUM>- and <NUM>,<NUM>-diaminotoluene and polyphenylpolymethylene polyamines, which may be obtained by aniline/formaldehyde condensation, or mixtures of two or more thereof.

Some suitable polyols include diol EO/PO (ethylene oxide/propylene oxide) block copolymers, EO-tipped polypropylene glycols, or alkoxylated bisphenol A.

Some suitable polyols include polyether polyols modified by vinyl polymers. These polyols can be obtained, for example, by polymerizing styrene or acrylonitrile or mixtures thereof in the presence of polyetherpolyol.

Some suitable polyols include polyester polyols. For example, it is possible to use polyester polyols obtained by reacting low molecular weight alcohols, more particularly ethylene glycol, diethylene glycol, neopentyl glycol, hexanediol, butanediol, propylene glycol, glycerol or trimethylol propane, with caprolactone. Other suitable polyhydric alcohols for the production of polyester polyols are <NUM>,<NUM>-hydroxymethyl cyclohexane, <NUM>-methyl propane-<NUM>,<NUM>-diol, butane-<NUM>,<NUM>,<NUM>-triol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol and polybutylene glycol.

Some suitable polyols include polyester polyols obtained by polycondensation. Thus, dihydric and/or trihydric alcohols may be condensed with less than the equivalent quantity of dicarboxylic acids and/or tricarboxylic acids or reactive derivatives thereof to form polyester polyols. Suitable dicarboxylic acids are, for example, adipic acid or succinic acid and higher homologs thereof containing up to <NUM> carbon atoms, unsaturated dicarboxylic acids, such as maleic acid or fumaric acid, cyclohexane dicarboxylic acid (CHDA), and aromatic dicarboxylic acids, more particularly the isomeric phthalic acids, such as phthalic acid, isophthalic acid or terephthalic acid. Citric acid and trimellitic acid, for example, are also suitable tricarboxylic acids. The acids mentioned may be used individually or as mixtures of two or more thereof. Polyester polyols of at least one of the dicarboxylic acids mentioned and glycerol which have a residual content of OH groups are suitable. Suitable alcohols include but not limited to propylene glycol, butane diol, pentane diol, hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexanedimethanol (CHDM), <NUM>-methyl-<NUM>,<NUM>-propanediol (MPDiol), or neopentyl glycol or isomers or derivatives or mixtures of two or more thereof. High molecular weight polyester polyols may be used in the second synthesis stage and include, for example, the reaction products of polyhydric, preferably dihydric, alcohols (optionally together with small quantities of trihydric alcohols) and polybasic, preferably dibasic, carboxylic acids. Instead of free polycarboxylic acids, the corresponding polycarboxylic anhydrides or corresponding polycarboxylic acid esters with alcohols preferably containing <NUM> to <NUM> carbon atoms may also be used (where possible). The polycarboxylic acids may be aliphatic, cycloaliphatic, aromatic or heterocyclic or both. They may optionally be substituted, for example by alkyl groups, alkenyl groups, ether groups or halogens. Suitable polycarboxylic acids are, for example, succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylene tetrahydrophthalic anhydride, glutaric anhydride, maleic acid, maleic anhydride, fumaric acid, dimer fatty acid or trimer fatty acid or mixtures of two or more thereof. Small quantities of monofunctional fatty acids may optionally be present in the reaction mixture.

The polyester polyol may optionally contain a small number of terminal carboxyl groups. Polyesters obtainable from lactones, for example based on ε-caprolactone (also known as "polycaprolactones"), or hydroxycarboxylic acids, for example ω-hydroxycaproic acid, may also be used.

Polyester polyols of oleochemical origin may also be used. Oleochemical polyester polyols may be obtained, for example, by complete ring opening of epoxidized triglycerides of a fatty mixture containing at least partly olefinically unsaturated fatty acids with one or more alcohols containing <NUM> to <NUM> carbon atoms and subsequent partial transesterification of the triglyceride derivatives to form alkyl ester polyols with <NUM> to <NUM> carbon atoms in the alkyl group.

Some suitable polyols include C36 dimer diols and derivatives thereof. Some suitable polyols include castor oil and derivatives thereof. Some suitable polyols include fatty polyols, for example the products of hydroxylation of unsaturated or polyunsaturated natural oils, the products of hydrogenations of unsaturated and polyunsaturated polyhydroxy natural oils, polyhydroxyl esters of alkyl hydroxyl fatty acids, polymerized natural oils, soybean polyols, and alkylhydroxylated amides of fatty acids. Some suitable polyols include the hydroxy functional polybutadienes known, for example, by the commercial name of "Poly-bd®" available from Cray Valley USA, LLC Exton, PA. Some suitable polyols include polyisobutylene polyols. Some suitable polyols include polyacetal polyols. Polyacetal polyols are understood to be compounds obtainable by reacting glycols, for example diethylene glycol or hexanediol or mixtures thereof, with formaldehyde. Polyacetal polyols may also be obtained by polymerizing cyclic acetals. Some suitable polyols include polycarbonate polyols. Polycarbonate polyols may be obtained, for example, by reacting diols, such as propylene glycol, butane-<NUM>,<NUM>-diol or hexane-<NUM>,<NUM>-diol, diethylene glycol, triethylene glycol or tetraethylene glycol or mixtures of two or more thereof, with diaryl carbonates, for example diphenyl carbonate, or phosgene. Some suitable polyols include polyamide polyols.

Some suitable polyols include polyacrylates containing OH groups. These polyacrylates may be obtained, for example, by polymerizing ethylenically unsaturated monomers bearing an OH group. Such monomers are obtainable, for example, by esterification of ethylenically unsaturated carboxylic acids and dihydric alcohols, the alcohol generally being present in a slight excess. Ethylenically unsaturated carboxylic acids suitable for this purpose are, for example, acrylic acid, methacrylic acid, crotonic acid or maleic acid. Corresponding OH-functional esters are, for example, <NUM>-hydroxyethyl acrylate, <NUM>-hydroxyethyl methacrylate, <NUM>-hydroxypropyl acrylate, <NUM>-hydroxypropyl methacrylate, <NUM>-hydroxypropyl acrylate or <NUM>-hydroxypropyl methacrylate or mixtures of two or more thereof.

The isocyanate reactive component can be a compound comprising an amine moiety. The amine moieties can be primary amine moieties, secondary amine moieties, or combinations of both. In some embodiments the compound comprises two or more amine moieties independently selected from primary amine moieties and secondary amine moieties (polyamine). In some embodiments the compound can be represented by a structure selected from HRN-Z and HRN-Z-NRH where Z is a hydrocarbyl group having <NUM> to <NUM> carbon atoms and R can be a covalent bond, H, hydrocarbyl, heterohydrocarbyl or polyether. In some embodiments Z is a straight or branched alkane or a straight or branched polyether. In some embodiments Z can be a heterohydrocarbyl group. In some embodiments Z can be a polymeric and/or oligomeric backbone. Such polymeric/oligomeric backbone can contain ether, ester, urethane, acrylate linkages. In some embodiments R is H. The term polyamine refers to a compound contains more than one -NHR group where R can be a covalent bond, H, hydrocarbyl, heterohydrocarbyl.

Some suitable amine compounds include but are not limited to aliphatic polyamines, arylaliphatic polyamines, cycloaliphatic polyamines, aromatic polyamines, heterocyclic polyamines, polyalkoxypolyamines, and combinations thereof. The alkoxy group of the polyalkoxypolyamines is an oxyethylene, oxypropylene, oxy-I,<NUM>-butylene, oxy-I,<NUM>-butylene or a co-polymer thereof.

Examples of aliphatic polyamines include, but are not limited to ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), trimethyl hexane diamine (TMDA), hexamethylenediamine (HMDA), N-(<NUM>- aminoethyl)-I,<NUM>-propanediamine (N3-Amine), N,N'-I,<NUM>-ethanediylbis-I,<NUM>- propanediamine (N4-amine), and dipropylenetriamine. Examples of arylaliphatic polyamines include, but are not limited to m-xylylenediamine (mXDA), and p- xylylenediamine. Examples of cycloaliphatic polyamines include, but are not limited to <NUM>,<NUM>-bisaminocyclohexylamine (<NUM>,<NUM>-BAC), isophorone diamine (IPDA), and <NUM>,<NUM>'- methylenebiscyclohexanamine. Examples of aromatic polyamines include, but are not limited to diethyltoluenediamine (DETDA), m-phenylenediamine, diaminodiphenylmethane (DDM), and diaminodiphenylsulfone (DDS). Examples of heterocyclic polyamines include, but are not limited to N-aminoethylpiperazine (NAEP), and <NUM>,<NUM>-bis(<NUM>-aminopropyl) <NUM>,<NUM>,<NUM>,<NUM>-tetraoxaspiro(<NUM>,<NUM>)undecane. Examples of polyalkoxypolyamines where the alkoxy group is an oxyethylene, oxypropylene, oxy- <NUM>,<NUM>-butylene, oxy-<NUM>,<NUM>-butylene or a co-polymer thereof include, but are not limited to <NUM>,<NUM>-dioxadecane-I,<NUM>-diamine, <NUM>- propanamine,<NUM>, I-ethanediyloxy))bis(diaminopropylated diethylene glycol). Suitable commercially available polyetheramines include those sold by Huntsman under the Jeffamine® trade name. Suitable polyether diamines include Jeffamines® in the D, SD, ED, XTJ, and DR series. Suitable polyether triamines include Jeffamines® in the T and ST series.

Suitable commercially available polyamines also include aspartic ester-based amine-functional resins (Bayer); dimer diamines e.g. Priamine® (Croda); or diamines such as Versalink® (Evonik).

The amine compound may include other functionalities in the molecule. The amine compound encompasses a single compound or a mixture of two or more amine compounds.

The isocyanate reactive component can be a thiol. In some embodiments the thiol comprises two or more -SH moieties (polythiol). In some embodiments the thiol comprises at least one -SH moiety and at least another functional moiety selected from -OH, -NH, -NH<NUM>, -COOH, or epoxide. In some embodiments the thiol can be represented by the structure HS-Z-SH where Z is a hydrocarbyl group, a heterohydrocarbyl group having <NUM> to <NUM> carbon atoms. In some embodiments Z is a straight or branched alkane or a straight or branched polyether. Some suitable thiols include but are not limited to pentaerythritol tetra-(<NUM>-mercaptopropionate) (PETMP), pentaerythritol tetrakis(<NUM>- mercaptobutylate) (PETMB), trimethylolpropane tri-(<NUM>-mercaptopropionate) (TMPMP), glycol di-(<NUM>-mercaptopropionate) (GDMP), pentaerythritol tetramercaptoacetate (PETMA), trimethylolpropane trimercaptoacetate (TMPMA), glycol dimercaptoacetate (GDMA), ethoxylated trimethylpropane tri(<NUM>-mercapto-propionate) <NUM> (ETTMP <NUM>), ethoxylated trimethylpropane tri(<NUM>-mercaptopropionate) <NUM> (ETTMP <NUM>), propylene glycol <NUM>- mercaptopropionate <NUM> (PPGMP <NUM>), propylene glycol <NUM>-mercaptopropionate <NUM> (PPGMP <NUM>), pentaerythritol tetrakis(<NUM>-mercaptobutanoate) (KarenzMT PE-<NUM> from Showa Denko), and soy polythiols (Mercaptanized Soybean Oil). The term "thiol" encompasses a single thiol or a mixture of two or more thiols.

The isocyanate reactive component can be a compound comprising an aminoalcohol moiety. As used herein an aminoalcohol moiety comprises at least one amino moiety and at least one hydroxyl moiety. In some embodiments the amine group is terminal to the aminoalcohol compound molecule. In some embodiments the amine group is a secondary amino group on the chain of the aminoalcohol compound molecule. In some embodiments the aminoalcohol compound includes a terminal primary amine and a secondary amine. In some embodiments the aminoalcohol compound can be represented by one of the following structures: HO-Z-NH-Z-OH or H<NUM>N-Z-NH-Z-OH or H<NUM>N-Z-(OH)<NUM> where Z is a hydrocarbyl group and/or an heterohydrocarbyl having <NUM> to <NUM> carbon atoms. In some embodiments Z is a straight or branched alkane or a straight or branched polyether. In some embodiments Z contains cycloaliphatic moiety or aryl moiety. Some suitable aminoalcohols include but are not limited to diethanolamine, dipropanolamine, <NUM>-amino-<NUM>,<NUM>-propanediol, <NUM>-amino-<NUM>,<NUM>-propane diol, <NUM>-amiono-<NUM>-methyl-<NUM>,<NUM>-propanediol, diisopropanolamine. The aminoalcohol compound encompasses a single compound or a mixture of two or more aminoalcohol compounds.

Suitable polyvinyl acetates to be included in the polyisocyanate component to increase the viscosity thereof include polyvinyl acetate homopolymers. Generally, the polyvinyl acetate homopolymer should form a homogenous mixture with the polyisocyanate component, as described in more detail below.

Suitable weight average molecular weights for the polyvinyl acetate homopolymer are from about <NUM> to <NUM>,<NUM> Daltons or from about <NUM>,<NUM> to <NUM>,<NUM> Daltons.

Suitable amounts of the polyvinyl acetate homopolymers to be included in the polyisocyanate component to increase the viscosity thereof range up to <NUM> weight percent, and preferably from <NUM> to <NUM> weight percent. The preferred range of the polyvinyl acetate homopolymer added to the polyisocyanate depends on the desired viscosity. The desired viscosity depends on the application, as well as the viscosity of the polyisocyanate reactive component in the two-component adhesive system. As is known in the art, generally if the viscosities of the two components are similar, they are mixed together more easily.

The additives disclosed herein can be contained in either or both of the polyisocyanate component or the polyisocyanate-reactive component (e.g. polyol or polyamine).

The curable compositions disclosed above can include a catalyst or cure-inducing component to modify speed of the initiated reaction. Some suitable catalysts are those conventionally used in polyurethane reactions and polyurethane curing, including organometallic catalysts, organotin catalysts and amine catalysts. Exemplary catalysts include (<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octane) DABCO® T-<NUM> or DABCO® crystalline, available from Evonik; DMDEE (<NUM>,<NUM>'-dimorpholinildiethylether); DBU (<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]undec-<NUM>-ene). The curable composition can optionally include from about <NUM>% to about <NUM>% by weight of composition of one or more catalysts or cure-inducing components. Preferably, the curable composition can optionally include from about <NUM>% to about <NUM>% by weight of composition of one or more catalysts or cure-inducing components.

The curable composition can optionally include filler. Some useful fillers include, for example, lithopone, zirconium silicate, hydroxides, such as hydroxides of calcium, aluminum, magnesium, iron and the like, diatomaceous earth, carbonates, such as sodium, potassium, calcium, and magnesium carbonates, oxides, such as zinc, magnesium, chromic, cerium, zirconium and aluminum oxides, calcium clay, nanosilica, fumed silicas, silicas that have been surface treated with a silane or silazane such as the AEROSIL® products available from Evonik Industries, silicas that have been surface treated with an acrylate or methacrylate such as AEROSIL® R7200 or R711 available from Evonik Industries, precipitated silicas, untreated silicas, graphite, synthetic fibers and mixtures thereof. When used, filler can be employed in concentrations effective to provide desired properties in the uncured composition and cured reaction products and typically in concentrations of about <NUM>% to about <NUM>% by weight of composition, more typically <NUM>% to <NUM>% by weight of composition of filler. Suitable fillers include organoclays such as, for example, Cloisite® nanoclay sold by Southern Clay Products and exfoliated graphite such as, for example, xGnP® graphene nanoplatelets sold by XG Sciences. In some embodiments, enhanced barrier properties are achieved with suitable fillers.

The curable composition can optionally include a thixotrope or rheology modifier. The thixotropic agent can modify rheological properties of the uncured composition. Some useful thixotropic agents include, for example, silicas, such as fused or fumed silicas, that may be untreated or treated so as to alter the chemical nature of their surface. Virtually any reinforcing fused, precipitated silica, fumed silica or surface treated silica may be used. Examples of treated fumed silicas include polydimethylsiloxane-treated silicas, hexamethyldisilazane-treated silicas and other silazane or silane treated silicas. Such treated silicas are commercially available, such as from Cabot Corporation under the tradename CAB-O-SIL® ND-TS and Evonik Industries under the tradename AEROSIL®, such as AEROSIL® R805. Also useful are the silicas that have been surface treated with an acrylate or methacrylate such as AEROSIL® R7200 or R711 available from Evonik Industries. Examples of untreated silicas include commercially available amorphous silicas such as AEROSIL® <NUM>, AEROSIL® <NUM> and AEROSIL® <NUM>. Commercially available hydrous silicas include NIPSIL® E150 and NIPSIL® E200A manufactured by Japan Silica Kogya Inc. The rheology modifier can be employed in concentrations effective to provide desired physical properties in the uncured composition and cured reaction products and typically in concentrations of about <NUM>% to about <NUM>% by weight of composition and advantageously in concentrations of about <NUM>% to about <NUM>% by weight of composition. In certain embodiments the filler and the rheology modifier can be the same.

The curable composition can optionally include an antioxidant. Some useful antioxidants include those available commercially from BASF under the tradename IRGANOX®. When used, the antioxidant should be used in the range of about <NUM> to about <NUM> weight percent of curable composition, such as about <NUM> to about <NUM> weight percent of curable composition.

The curable composition can optionally include a reaction modifier. A reaction modifier is a material that will increase or decrease reaction rate of the curable composition. For example, <NUM>-hydroxyquinoline (<NUM>-HQ) and derivatives thereof such as <NUM>-hydroxymethyl-<NUM>-hydroxyquinoline can be used to adjust the cure speed. When used, the reaction modifier can be used in the range of about <NUM> to about <NUM> weight percent of curable composition.

The curable composition can optionally contain a thermoplastic polymer in addition to polyvinyl acetate homopolymer. Non-limiting examples of suitable thermoplastic polymers include acrylic polymer, functional (e.g. containing reactive moieties such as -OH and/or -COOH) acrylic polymer, non-functional acrylic polymer, acrylic block copolymer, acrylic polymer having tertiary-alkyl amide functionality, polysiloxane polymer, polystyrene copolymer, divinylbenzene copolymer, polyetheramide, polyvinyl acetal, polyvinyl butyral, polyvinyl chloride, methylene polyvinyl ether, cellulose acetate, styrene acrylonitrile, amorphous polyolefin, olefin block copolymer [OBC], polyolefin plastomer, thermoplastic urethane, polyacrylonitrile, ethylene acrylate copolymer, ethylene acrylate terpolymer, ethylene butadiene copolymer and/or block copolymer, styrene butadiene block copolymer, and mixtures of any of the above.

The curable composition can optionally include one or more adhesion promoters that are compatible and known in the art. Examples of useful commercially available adhesion promoters include amino silane, glycidyl silane, mercapto silane, isocyanato silane, vinyl silane, (meth)acrylate silane, and alkyl silane. Common adhesion promoters are available from Momentive under the trade name Silquest or from Wacker Chemie under the trade name Geniosil. Silane terminated oligomers and polymers can also be used. The adhesion promoter can be used in the range of about <NUM>% to about <NUM>% percent by weight of curable composition and advantageously in the range of about <NUM>% to about <NUM>% percent by weight of curable composition.

The curable composition can optionally include one or more coloring agents. For some applications a colored composition can be beneficial to allow for inspection of the applied composition. A coloring agent, for example a pigment or dye, can be used to provide a desired color beneficial to the intended application. Exemplary coloring agents include titanium dioxide, C. Pigment Blue <NUM>, C. Pigment Yellow <NUM> and phthalocyanine blue BN. In some applications a fluorescent dye can be added to allow inspection of the applied composition under UV radiation. The coloring agent will be present in amounts sufficient to allow observation or detection, for example about <NUM>% or more by weight of total composition. The maximum amount is governed by considerations of cost, absorption of radiation and interference with cure of the composition. More desirably, the coloring agent may be present in amounts of up to about <NUM>% by weight of total composition.

The curable composition can optionally include from about <NUM>% to about <NUM>% by weight, for example about <NUM>% to about <NUM>% by weight of composition of other additives known in the arts, such as tackifier, plasticizer, flame retardant, diluent, reactive diluent, moisture scavenger, and combinations of any of the above, to produce desired functional characteristics, providing they do not significantly interfere with the desired properties of the curable composition or cured reaction products of the curable composition.

When used as an adhesive, the curable compositions can optionally include up to <NUM>% by weight of the total weight of the curable composition of a suitable solvent. This type of adhesives is known as solvent-based adhesives. Upon application of the curable composition on a first substrate, the solvent is quickly evaporated away, for example by heated ovens, then a second substrate is laminated onto the curable composition coated side of the first substrate to form a laminated structure.

The isocyanate was heated to <NUM> above the softening temperature of the PVAc material in a double planetary mixer equipped with heating and cooling. This mixing temperature therefore ranged from <NUM> to <NUM>. Once the isocyanate was heated to the target temperature, the PVAc resin (homopolymer or copolymer) was added to the isocyanate and mixed for approximately one hour. Generally, one hour was an adequate time to achieve a complete incorporation of the polymer comprising as polymerized units vinyl acetate or vinyl acetate and vinyl chloride into the isocyanate, if the isocyanate and the polymer resin could form a homogeneous mixture. The homogeneous samples were cooled to approximately <NUM> before discharge.

The term "homogeneous" as used herein is understood to mean that the material is single phase and predominately or completely free from bubbles, unmixed solids, and heterogeneity upon visual inspection and probing with a spatula after cooling. The material appears smooth and consistent during pouring.

In order to assess long-term stability of the samples, the samples were stored at room temperature for at least two months under nitrogen without component separation or reaction. Some samples have been determined to be stable for at least six months under these conditions.

Viscosities of all of the samples were measured at <NUM> using a Brookfield Viscometer at <NUM> RPM and <NUM> RPM, with RV Spindle <NUM>. All of the viscosities reported herein are as measured at <NUM> RPM.

Lap shear samples were prepared using Birch substrate TS <NUM> (<NUM>" x <NUM>" x <NUM>"), with a <NUM>" overlap, and TS <NUM><NUM>" spacer wire. Samples were controlled at a <NUM> index, so mix ratio was measured by weight. Samples were added to a mixing cup, mixed for <NUM> at <NUM> rpm, and added to the substrate with <NUM> spacer wires. Samples were left to cure for <NUM> days at room temperature. Samples were pulled at <NUM> inch/min. <NUM> samples were pulled and averaged. "Index" is understood to mean: (number of isocyanate groups/number of groups reacting with the isocyanate) X <NUM>.

The weight percent NCO (isocyanate) as listed in the following examples is calculated.

Particular polyisocyanate compounds used herein include the following:.

All polymer molecular weights (MW are weight average molecular weight in Daltons.

The following compositions were mixed according to the general mixing procedure described above. <NUM>% of each thermoplastic was mixed with <NUM>% by weight with each isocyanate composition. The compatible mixtures were those that formed a homogeneous mixture after approximately an hour of mixing and remained homogenous and did not degrade, crystallize or undergo a significant change in viscosity after at least two months of storage under nitrogen.

Properties of the particular materials used are listed below:
The results are presented below in Table <NUM>.

This example illustrates the surprising compatibility and the viscosity-increasing ability of the polyvinyl acetate homopolymers of a range of molecular weights and a poly (vinyl acetate/vinyl chloride) copolymer compared to other polymers and copolymers of vinyl acetate.

Pre-polymer <NUM> comprising <NUM>% polyisocyanate as Mondur® MB (<NUM>,<NUM>'-methylene diphenyl diisocyanate, <NUM> wt% NCO, MW = <NUM>, functionality = <NUM>, Covestro) and <NUM>% polypropylene glycol (ARCOL® POLYOL PPG <NUM>: Molecular weight = <NUM>, functionality = <NUM>) was synthesized according to the following procedure: The pre-polymer <NUM> made according to this method had NCO weight % of <NUM> and a Brookfield viscosity at <NUM> of <NUM> mPa·sec using spindle <NUM> at <NUM> RPM.

<NUM>% by weight of MDI (<NUM>,<NUM>'-methylene diphenyl diisocyanate as Mondur® MB from Covestro) was melted at <NUM> prior to use. The melted MDI was charged into a reactor at <NUM>. Then <NUM>% by weight of PPG (polypropylene glycol as ARCOL® POLYOL PPG <NUM>) was added to the reactor. These reactants were mixed at <NUM> for <NUM> hour under nitrogen, and then packaged under nitrogen.

The following samples were prepared by making a <NUM> percent by weight polyvinyl acetate masterbatch of pre-polymer <NUM> according to the general mixing procedure described above and then diluting the masterbatch as necessary with pre-polymer <NUM>.

The viscosity was measured with a Brookfield rheometer at <NUM> rpm using spindle <NUM>. The percent NCO shown in the table is calculated. The composition of the mixtures and the obtained viscosities are shown below in Table <NUM>:.

The viscosity of the prepolymer <NUM> as a function of the amount of added polyvinyl acetate is shown in <FIG>.

Example <NUM> is similar to Example <NUM>, except that a quasi-pre-polymer was used instead of the prepolymer1. The quasi-pre-polymer used was Desmodur® E-<NUM> (Covestro). Desmodur E-<NUM> contains significant amounts of monomeric <NUM>,<NUM> MDI in addition to an isocyanate functional prepolymer. The various samples were made according to the same procedure described in Example <NUM>, i.e. a masterbatch was prepared according to the general procedure and then diluted as necessary with the quasi-pre-polymer to obtain the desired weight percent of polyvinyl acetate.

The results are shown in Table <NUM> and the viscosity of the Desmodur® E-<NUM> in mPa·s as a function of the amount of polyvinyl acetate is shown in <FIG>. The viscosity was measured with a Brookfield rheometer at <NUM> rpm using spindle <NUM>. The percent NCO shown in the table is calculated.

Surprisingly, while monomeric <NUM>,<NUM> MDI does not exhibit thickening effects the Desmodur E-<NUM> containing a significant amount of monomeric <NUM>,<NUM> MDI in addition to an isocyanate functional prepolymer thickened appreciably.

Example <NUM> is similar to Example <NUM>, except that a polymeric MDI was used instead of the quasi-pre-polymer. The polymeric MDI that was used was a commercially available product, Mondur® MR-Light (Covestro). The various samples were made according to the same procedure described in Example <NUM>, i.e. a masterbatch was prepared according to the general procedure and then diluted as necessary with the polymeric MDI to obtain the desired weight percent of polyvinyl acetate.

The results are shown below in Table <NUM> and the viscosity of Mondur® MR-Light in mPa·s as a function of the amount of added polyvinyl acetate is shown in <FIG>. The viscosity was measured with a Brookfield rheometer at <NUM> rpm using spindle <NUM>. The percent NCO shown in the table is calculated.

Various polyisocyanate/polyvinyl acetate compositions, prepared according to the general procedure, were mixed with the polyol component of a standard two-component polyurethane adhesive (Loctite® UK U-05FL, Henkel) in order to evaluate the effect of the polyvinyl acetate on the shear adhesion of the two-component polyurethane adhesive composition. The relative amounts of polyisocyanate/polyvinyl acetate component and polyol component of the Loctite® UK U-05FL were selected to obtain an isocyanate index of <NUM> (i.e. the molar ratio of isocyanate groups to hydroxyl groups was <NUM>:<NUM>). The lap shear strength of the samples were measured and compared to the standard two component adhesive Loctite® UK U-05FL.

The samples were prepared and tested as follows:
Lap shear samples were prepared using birch substrate and spacer wire. Samples were controlled at a <NUM> Index, so the mix ratio was measured by weight. Adhesive samples were prepared by adding the appropriate amounts of the polyisocyanate/polyvinyl acetate component and the Loctite® UK U-05FL polyol component to a mixing cup, and then mixing for <NUM> minute at <NUM> rpm. These adhesive samples were then applied in between two pieces of the birch substrate (<NUM>" x <NUM>" x <NUM>" South End Wood Working and Supply), with a <NUM>" overlap. Two spacer wires <NUM>" from Atlantic Precision Spring were placed in the adhesive of each overlapped area. The samples were left to cure for <NUM> days at room temperature and then tested.

These samples were pulled at <NUM>/min and the lap shear strength in mPa was recorded. Five samples of each adhesive sample were pulled and the averages for each composition are reported in Table <NUM> along with the standard deviation.

Claim 1:
A two-component curable composition comprising:
a component A comprising at least one isocyanate-reactive composition, and a component B wherein component B is an isocyanate functional composition comprising:
a) an isocyanate material comprising a polyisocyanate, wherein the polyisocyanate comprise polymeric diphenylmethanediisocyanate, isocyanate functional pre-polymer, or mixtures thereof, has an average isocyanate functionality of at least <NUM>; and
b) a polyvinyl acetate homopolymer;
wherein the polyisocyanate has a viscosity of at least <NUM> mPa·sec measured on a Brookfield viscometer at <NUM> RPM with spindle <NUM> at <NUM>, conditioned for at least <NUM> hours at <NUM> with spindle <NUM>, prior to the addition of the polyvinyl acetate homopolymer,
wherein component B is a homogeneous mixture at <NUM>,
wherein component B has a component B viscosity in a range of <NUM> mPa·sec to <NUM>,<NUM> mPa·sec measured on a Brookfield viscometer at <NUM> RPM with spindle <NUM> at <NUM>, conditioned for at least <NUM> hours at <NUM> with RV Spindle <NUM>, and
wherein the amount of component b) ranges up to <NUM> weigh percent in component B.