US 4,791,168 AGranted

Polyurethane resins in water-dilutable basecoats having low flash and quick-drying characteristics

AssigneeBASF Corporation, Inmont Division

InventorsTimothy Salatin, Thomas C. Balch, Michael C. Knight, Michael D. Shesterkin, John S. Van Antwerp, Paul E. Lamberty, Robert A. Aamodt

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Abstract

This invention, therefore, relates to the field of polyurethane coatings for use in automobile basecoat/clearcoat systems. In particular, this invention relates to the discovery that incorporating a long-chain carboxylic acid of at least 50% by weight of the carboxylic acid component used to make polyester resins which are further incorporated into polyurethane resins provides basecoat composition exhibiting low temperature flash characteristics. These low temperature flash characteristics are exhibited even where the basecoat is deposited at 50-90% relative humidity.

Claims55

Dependent claims

A basecoat composition suitable for deposition onto metal or plastic comprising:

(a) about 20 to 80% weight percent based on the final solids content of said basecoat composition of an anionic polyurethane principal resin comprised of the reaction product of:
(i) a polyester component comprised of the reaction product of a carboxylic acid component with an alcohol having at least two hydroxyl groups wherein said carboxylic acid component is comprised of at least about 50% by weight of at least one long-chain carboxylic acid having between 18 and 60 carbon atoms and at most about 50% of at least one short-chain dicarboxylic acid;
(ii) a multi-functional compound having at least one active hydrogen and at least one carboxylic acid functionality;
(iii) a compound having at least 2 active hydrogen groups selected from the group consisting of hydroxyl, sulfhydryl, primary amine, and secondary amine, one of said primary amines accounting for one active hydrogen and;
(iv) a polyisocyanate;
(b) about 5 to about 50% by weight of an aminoplast cross-linking resin;
(c) 5 to about 35 weight percent of a branched chain polyester resin comprised of the reaction product of:
(i) a polyester component comprised of the reaction product of
(1) a carboxylic acid component comprised of at least 50% by weight of at least one long chain carboxylic acid containing compound having between 18 and 60 carbons and not more than 50% by weight of at least one short-chain dicarboxylic acid;
and
(2) an alcohol component having an average functionality of at least 2;
and
(ii) 2-25% by weight of a polyfunctional carboxylic acid or acid anhydride, said polyfunctional carboxylic acid or acid anhydride having at least 3 carboxylic acid groups;
and
(d) about 2 to 75 weight percent of a pigment-containing grind resin comprising:
(i) About 6 to about 60% by weight of said pigment-containing grind resin of a pigment;
(ii) About 20 to about 75% by weight of said pigment-containing grind resin of a polyurethane resin produced by the reaction product of:
(1) a polyester resin component produced by the reaction of a carboxylic acid component comprised of at least 50% by weight of a long-chain carboxylic acid having between 18 and 60 carbon atoms and at most about 50% of a short chain dicarboxylic acid and an alcohol having at least 2 hydroxyl groups;
and
(2) a mixture of a multi-functional compound having at least 1 active hydrogen and at least one carboxylic acid functinality, at least one compound having at least two active hydrogen groups, and a polyisocyanate, said carboxylic acid groups being neutralized with an amine;
and
(iii) About 20% to about 60% by weight of said pigment-containing grind resin of an aminoplast cross-linking agent.

19 more elements

A method of coating an automobile substrate with a multilayer coating comprising:

(a) applying to the primed substrate old at least one layer of a waterborne coating composition comprised of:
(i) a polyurethane resin obtained from the reaction product of:
(1) a polyester resin component produced by the reaction of a carboxylic acid component comprised of at least 50% by weight of a long-chain carboxylic acid having between 18 and 60 carbon atoms and at most about 50% of a short chain dicarboxylic acid and an alcohol having at least 2 hydroxyl groups;
and
(2) a mixture of a multi-functional compound having at least 1 active hydrogen functionality and at least one carboxylic acid functionality, at least one compound having at least two active hydrogen groups, and polyisocyanate, said carboxylic acid groups being neutralized with an amine;
(ii) a cross-linking agent;
(iii) a rheology control agent;
and
(iv) a pre-formed branched chain polyester resin comprised of the reaction product of:
(1) (A) a polyester component comprised of the reaction product of a carboxylic acid component comprised of at least 50% by weight of a long chain carboxylic acid having between 18 and 60 carbons, no more than about 50% by weight of a short-chain dicarboxylic acid and between about 2 and 25% by weight of a polyfunctional carboxylic acid having at least 3 carboxylic acid groups;
and
(B) an alcohol component having an average functionality of at least 2;
and
(2) between about 2 and 25% by weight of a polyfunctional carboxylic acid having at least 3 carboxylic acid groups,
(b) flash drying said basecoats;
and
(c) applying at least one layer of a clear topcoat onto said basecoat;
and
(d) curing said basecoats and topcoat to a hard, durable film.

16 more elements

A multi-coated metal or plastic substrate comprising:

a substrate coated with at least one waterborne basecoat composition comprising:
(a) about 20 to 80% weight percent based on the final solids content of said basecoat composition of a first anionic polyurethane resin comprised of the reaction product of:
(i) a polyester component with an alcohol having at least two hydroxyl groups wherein said carboxylic acid component is comprised of at least about 50% by weight of a long-chain carboxylic acid having between 18 and 60 carbon atoms and at most about 50% of a short chain dicarboxylic acid:
(ii) a multi-functional compound having at least 1 active hydrogen functionality and at least one carboxylic acid functionality;
(iii) a compound having at least 2 active hydrogen groups;
(iv) a polyisocyanate;
and
(v) an amine-containing compound for neutralizing the free carboxylic acid groups;
(b) about 5 to about 50 weight percent of an aminoplast cross-linking resin;
(c) about 0.1 to about 25 weight percent of a rheology control agent, selected from the group consisting of fumed silica compounds, bentonite clays, and hectorite clays;
(d) about 0 to about 35 weight percent of a branched chain polyester resin comprised of the reaction product of;
(i) a carboxylic acid component comprised of at least 50% by weight of a long chain carboxylic acid having between 18 and 60 carbons, no more than about 48% by weight of a short-chain dicarboxylic acid and between 2 and 25% by weight of a polyfunctional carboxylic acid or acid anhydride, said polyfunctional carboxylic acid having at least 3 carboxylic acid groups;
and
(ii) an alcohol component having an average functionality of at least 2;
and
(e) about 2 to about 75 weight percent of a pigment,
each of said basecoat compositions being flash-dried before being coated with a clear topcoating, said basecoat composition and said topcoating being cured to a hard, durable film.

14 more elements

A method of making a waterborne basecoat composition for use in a multi-layer coating comprised of

(A) an anionic polyurethane resin comprised of
(1) a polyester resin component produced by the reaction of a carboxylic acid component comprised of at least 50% by weight of a long-chain acid having between 18 and 60 carbon atoms and at most about 50% of a short-chain dicarboxylic acid and an alcohol having at least 2 hydroxyl groups;
and
(2) a mixture of at least one multi-functional compound having at least 1 active hydrogen functionality and at least one carboxylic acid functionality, at leat one compound having at least two active hydrogen groups, and a polyisocyanate, said carboxylic acid group being neutralized with an amine,
(B) a crosslinking agent, and
(C) a rheology control agent, comprising the sequential steps of:
(a) adding the crosslinking agent in solution to the rheology control agent in solution and thoroughly mixing;
(b) adding an aqueous dispersion of the anionic polyurethane resin under agitation and thoroughly mixing.

5 more elements

Dependencies are inferred from the claim text.