Coating compositions containing acrylic and aliphatic polyester blends

摘要

Disclosed are solvent borne thermosetting coating compositions containing curable, aliphatic polyesters, acrylic copolymers, crosslinkers, and nonaqueous solvents. The aliphatic polyesters contain 2,2,4,4-tetramethyl-1,3-cyclobutanediol. Blends of acrylic copolymers with these aliphatic polyesters exhibit good compatibility, viscosity reduction, and good Tg retention. Coating compositions formulated from these blends exhibit high gloss, hardness with flexibility; solvent and chemical resistance; and outdoor durability.

主权项

1. A thermosetting coating composition, comprising:
(A). about 2 to about 50 weight percent, based on the total weight of (A), (B), and (C) of a curable, aliphatic polyester, consisting of i. diacid residues, comprising at least 90 mole percent, based on the total moles of diacid residues, of the residues of at least one aliphatic diacid, said aliphatic diacid comprising from about 50 to 100 mole percent of a cycloaliphatic dicarboxylic acid ii. diol residues, comprising about 50 to 100 mole percent, based on the total moles of diol residues, of the residues of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on the total moles of diol residues; and iii. about 3 to about 30 mole percent of the residues of at least one polyol chosen from trimethylolpropane, pentaerythritol, trimethylolethane, erythritol, threitol, dipentaerythritol, sorbitol, and glycerine, based on the total moles of diol and polyol residues;
wherein said curable, aliphatic polyester has a number average molecular weight of from about 300 to about 10,000 daltons, a glass transition temperature of about −35° C. to about 35° C., a hydroxyl number of about 20 to about 450 mg KOH/g of polyester, and an acid number of 0 to about 80 mg KOH/g of polyester; (B). about 25 to about 88 weight percent, based on the total weight of (A), (B), and (C) of at least one acrylic copolymer of ethylenically unsaturated monomers comprising at least one hydroxyl, epoxy, carboxyl, blocked phenol, or acetoacetoxy functional group; (C). about 10 to about 50 weight percent, based on the total weight of (A), (B), and (C), of at least one crosslinker comprising at least one compound reactive with a carboxylic acid or a hydroxyl group; and (D). about 10 to about 60 weight percent, based on the total weight of (A), (B), (C), and (D) of at least one non-aqueous solvent.