Patent ID: 6528593
Filing Date: 2003-03-04
Classification: C04B,C08G,C08L

Abstract:
Process for the preparation of a copolymer containing structural units derived from a) at least one monomer selected from the group consisting of &agr;,&bgr;-unsaturated mono-carboxylic acids and their salts; and &agr;,&bgr;-unsaturated dicarboxylic acids, their half-esters free of polyalkylene oxide side chains and salts thereof, b) an aromatic vinyl compound and c) a hydrophobic moiety, said hydrophobic moiety being incorporated into the copolymer chain;said process comprises reacting, in an aqueous medium, a) at least one monomer selected from the group consisting of &agr;,&bgr;-unsaturated mono-carboxylic acids and their salts; and &agr;,&bgr;-unsaturated dicarboxylic acids, their half-esters free of polyalkylene oxide side chains and salts thereof; b) at least one aromatic vinyl compound; and c) at least one hydrophobic compound free of olefinic unsaturation containing units of the formula: â€ƒwherein R1 is independently at each occurrence selected from hydrogen and C1-C4 alkyl, with the proviso that at least one R1 is selected from the group consisting of C1-C4 alkyl, the hydrophobic compound(s) c) being present in an amount of 0.01 to 30 weight percent, based on the total amount of a), b) and c); at a temperature in the range of 25Â° C. to 100Â° C., and in the presence of a free-radical initiator in an amount of 1.0 weight percent to 25 weight percent, based on the total weight of a), b) and c).