Process for the production of hydroxy-functional copolymers

Claim 1

A process for the production of a hydroxy-functional copolymer by radical-initiated copolymerization of monomers in the absence of a solvent comprising a) heating to a polymerization temperature of from about 130° to about 200° C. a mixture comprising A) from about 5 to about 30 parts by weight of at least one polyester polyol with a hydroxyl number of from about 40 to about 180 at an acid value of less than 12 and a glass transition temperature of from about -40° to about 80° C. and B) from about 1 to about 10 parts by weight of an olefinically unsaturated maleic acid di(cyclo)alkyl ester having from 1 to 12 carbon atoms in the (cyclo)alkyl group, and b) adding to the mixture from a) C) from about 42 to about 93,5 parts by weight of a monomer mixture of (1) from 0 to about 70 parts by weight of methyl methacrylate, (2) from 0 to about 60 parts by weight of at least one (cyclo)alkyl ester of acrylic and/or methacrylic acid having 2 to 18 carbon atoms in the (cyclo)alkyl group, (3) from about 10 to about 60 parts by weight of at least one vinyl aromatic, (4) from about 6 to about 40 parts by weight of (i) hydroxyalkyl esters of acrylic and/or methacrylic acid having from 2 to 6 carbon atoms in the hydroxyalkyl group and/or (ii) a reaction product of at least one ester of (i) with ε-caprolactone having a molecular weight of no greater than 500, and (5) from 0 to about 5 parts by weight of an olefinically unsaturated carboxylic acid, in which the sum of the parts by weight of (1), (2), (3), (4) and (5) is 100, and D) from about 0.5 to about 8 parts by weight of an initiator for radical polymerization at a temperature of from about 130° to about 200° C. with the sum of A), B), C) and D) being 100.