Patent ID: 6048936
Filing Date: 2000-04-11
Classification: C08F,C09D

Abstract:
An acrylate copolymer (AB) obtained by addition polymerization of a monomer mixture (A), in an organic solvent or in bulk, the monomer mixture (A) comprising proportions by mass of(Aa) from 25 to 80% of one or more C.sub.1 -C.sub.20 -alkyl (meth)acrylates, whose alkyl radicals can be linear, branched, or cyclic,(Ab) from 1 to 28% of one or more C.sub.2 -C.sub.20 -hydroxyalkyl (meth)acrylates whose hydroxyalkyl radicals can be linear, branched, or cyclic,(Ac) from 0.5 to 20% of one or more .alpha.,.beta.-unsaturated carboxylic acids, andvinyl compounds, aliphatic vinyl esters, aliphatic vinyl ethers, vinyl halides, esters of glycidyl alcohol or methylglycidyl alcohol with olefinically unsaturated carboxylic acids, or nitriles of .alpha.,.beta.-unsaturated carboxylic acids,wherein the sum of the proportions by mass of the components (Aa) to (Ad) is 100%,in the presence of one or mote free-radical polymerization initiators and of at least one(B) polyester or polyester oligomer obtained by polycondensation of the or more polyols(Ba) and one or more polycarboxylic acids(Bb) and having a hydroxyl number of from 50 to 350 mg/g, an acid number of from 1 to 50 mg/g and a weight-average molar mass M.sub.w of up to 5000 g/mol,with the proviso that the polyesters or polyester oligomers present during the addition polymerization of the mixture (A) are free from olefinic double bonds, that the proportion by mass of component (B) in the end product (AB) is less than 10%, of the mass thereof and that this end product (AB) has an acid number of from 5 to 45 mg/g, a hydroxyl number of from 40 to 125 mg/g and a weight-average molar mass M.sub.w of from about 3000 to about 10,000 g/mol, and a polydispersity (=M.sub.w /M.sub.n ; nonuniformity) of about 1.5 through 3.