Coating containing acrylosilane polymer to improve mar and acid etch resistance

Claim 2

A coating composition comprising 40-70% by weight of film forming binder and 30-60% by weight of a volatile liquid carrier for the binder; wherein the binder comprises about a. 30-70% by weight, based on the weight of the binder, of an acrylic polymer consisting essentially of polymerized monomers selected from the group consisting of an alkyl methacrylate, an alkyl acrylate, each having 1-12 carbon atoms in the alkyl group, isobornyl methacrylate, isobornyl acrylate, hydroxy alkyl methacrylate, hydroxy alkyl acrylate each having 1-4 carbon atoms in the alkyl group, styrene and any mixtures thereof; b. 5-30% by weight, based on the weight of the binder, of an acrylosilane polymer consisting essentially of polymerized monomers selected from the group consisting of an alkyl methacrylate, an alkyl acrylate, each having 1-12 carbon atoms in the alkyl group, isobornyl methacrylate, isobornyl acrylate, hydroxy alkyl methacrylate, hydroxy alkyl acrylate each having 1-4 carbon atoms in the alkyl group, styrene and any mixtures thereof and an ethylenically unsaturated hydroxy functional acrylosilane monomer; and c. 25-50% by weight, based on the weight of the binder of an organic polyisocyanate comprising a mixture of the trimer of hexamethylene diisocyanate and the isocyanurate of isophorone diisocyanate.

Claim 3

The coating composition of claim 1 in which the acrylosilane polymer consists essentially of polymerized monomers of an alkyl methacrylate, an alkyl acrylate, each having 1-12 carbon atoms in the alkyl group, isobornyl methacrylate, styrene, hydroxy alkyl methacrylate having 1-4 carbon atoms in the alkyl group and a silane containing monomer having the following structural formula: ##STR4## wherein: R is selected from the group consisting of CH 3 , CH 3 CH 2 , CH 3 O, or CH 3 CH 2 O; R 1 and R 2 are individually selected from the group consisting of CH 3 , or CH 3 CH 2 ; and R 3 is selected from the group consisting of H, CH 3 , or CH 3 CH 2 and n is 0 or a positive integer of 1-10.

Claim 4

The coating composition of claim 2 in which the silane is selected from the group consisting of gamma trimethoxy silyl propyl methacrylate and gamma trimethxoy silyl propyl acrylate.

Claim 5

The coating composition of claim 1 containing about 1-20% by weight, based on the weight of the binder, of a polyester resin consisting essentially of the esterification product of an aliphatic dicarboxylic acid, a polyol having at least three reactive hydroxyl groups, a diol, a cyclic anhydride, and a cyclic alcohol.

Claim 6

The coating composition of claim 4 in which the polyester resin is the esterification product of adipic acid, trimethylol propane, hexanediol, hexahydrophthalic anhydride and cyclohexane dimethalol.

Claim 7

The coating composition of claim 1 which contains about 1-10% by weight of ultraviolet light absorbers.

Claim 8

The coating composition of claim 1 in which the binder consists essentially of about a. 25-50% by weight, based on the weight of the binder, of acrylic polymer consisting essentially of polymerized monomers of an alkyl methacrylate, an alkyl acrylate, each having 1-4 carbon atoms in the alkyl group, isobornyl methacrylate, hydroxy alkyl methacrylate, having 1-4 carbon atoms in the alkyl group and styrene and having a number average molecular weight of about 1,000-3,000; b. 5-20% by weight, based on the weight of the binder, of acrylosilane polymer consisting essentially of polymerized monomers of an alkyl methacrylate, an alkyl acrylate, each having 1-8 carbon atoms in the alkyl group, isobornyl methacrylate, styrene, hydroxy alkyl methacrylate having 1-4 carbon atoms in the alkyl group and a silane containing monomer of gamma trimethoxy silyl propyl methacrylate or gamma trimethoxy silyl propyl acrylate and having a number average molecular weight of about 1,000-10,000; c. 0-20% by weight, based on the weight of the binder, of polyester resin consisting essentially of the esterification product of an aliphatic dicarboxylic acid, a polyol having at least three reactive hydroxyl groups, a diol, a cyclic anhydride, and a cyclic alcohol and having a number average molecular weight of about 500-4000; and d. 25-50% by weight, based on the weight of the binder, of organic polyisocyanate consisting essentially of a mixture of the trimer of hexamethylene diisocyanate and the isocyanurate of isophorone diisocyanate.

Claim 9

A substrate coated with a pigmented base coat and topcoated with a layer of the coating composition of claim 1.