Ambient curing water-borne compositions comprising half esters of anhydride polymers crosslinked by epoxies
First Claim
1. A coating composition, in the form of a multipackage system, for producing a clearcoat, said coating composition comprising 20-80% by weight of reactive binder components and 80-20% by weight of an aqueous liquid carrier comprising at least 60% by weight water;
- wherein the binder comprises;
(a) 25-90% by weight, based on the weight of the binder, of a half-ester product of an acrylic copolymer having at least two reactive anhydride groups and comprising polymerized monomers of an ethylenically unsaturated arthydride or an ethylenically unsaturated dicarboxylic acid, which has been converted to an anhydride, and polymerized monomers selected from the group consisting of alkyl methacrylate, alkyl acrylate and any mixtures thereof, wherein the alkyl groups have 1-8 carbon atoms and the polymer has a weight average molecular weight of about 2,000-100,000, wherein equal to or greater than 90% of the arthydride groups on said acrylic copolymer have been half-esterifed by reaction with an alcohol;
(b) 5-50% by weight, based on the weight of the binder, of a glycidyl ether or ester or cycloaliphatic epoxy compound containing at least two reactive glycidyl groups;
(c) an effective amount of a base to neutralize the half-ester acrylic copolymer (a) above; and
(d) 0.1-8% by weight, based on the weight of binder, of a curing catalyst, wherein the components are selected such that the composition is capable of forming a clearcoat automotive refinish that can be cured at 10°
to 90°
C. after being applied, and wherein components (a) and (b) are kept separate in said multi-package system until shortly before application.
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Abstract
An ambient cured aqueous coating composition useful for maintenance coatings for architectural structures or for a finish or refinish for automobiles and trucks. The film-forming binder comprises a neutralized half-ester product of an acrylic polymer having at least two reactive anhydride groups and an epoxy-containing, optionally silane-containing crosslinker. The composition may be used as a mulit-package system. The composition is characterized by improved environmental resistance and excellent clarity and appearance, particularly for clearcoats.
10 Citations
14 Claims
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1. A coating composition, in the form of a multipackage system, for producing a clearcoat, said coating composition comprising 20-80% by weight of reactive binder components and 80-20% by weight of an aqueous liquid carrier comprising at least 60% by weight water;
- wherein the binder comprises;
(a) 25-90% by weight, based on the weight of the binder, of a half-ester product of an acrylic copolymer having at least two reactive anhydride groups and comprising polymerized monomers of an ethylenically unsaturated arthydride or an ethylenically unsaturated dicarboxylic acid, which has been converted to an anhydride, and polymerized monomers selected from the group consisting of alkyl methacrylate, alkyl acrylate and any mixtures thereof, wherein the alkyl groups have 1-8 carbon atoms and the polymer has a weight average molecular weight of about 2,000-100,000, wherein equal to or greater than 90% of the arthydride groups on said acrylic copolymer have been half-esterifed by reaction with an alcohol; (b) 5-50% by weight, based on the weight of the binder, of a glycidyl ether or ester or cycloaliphatic epoxy compound containing at least two reactive glycidyl groups; (c) an effective amount of a base to neutralize the half-ester acrylic copolymer (a) above; and (d) 0.1-8% by weight, based on the weight of binder, of a curing catalyst, wherein the components are selected such that the composition is capable of forming a clearcoat automotive refinish that can be cured at 10°
to 90°
C. after being applied, and wherein components (a) and (b) are kept separate in said multi-package system until shortly before application. - View Dependent Claims (2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14)
- wherein the binder comprises;
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5. The coating composition of claim I in which the glycidyl component is selected from the group consisting of a polyglycidyl ether of low molecular weight polyol, an epoxy resin of epichlorohydrin and bisphenol A, a polyglycidyl ester of poly carboxylic acid, a polyglycidyl ether of isocyanurate, a glycidyl methacrylate or glycidyl acrylate containing acrylic polymer, and mixtures of any of the above.
Specification