Patent ID: 7465440

Claim:
A process for preparing graft copolymers of polyvinyl esters which comprises polymerizing a) at least one vinyl ester of aliphatic C 1 -C 24 -carboxylic acids in the presence of b) polyethers which are solid at room temperature and have the general formula I R 1 O—(R 2 —O) u —(R 3 —O) v —(R 4 —O) w A—(R 5 —O) x —(R 6 —O) y —(R 7 —O) z s R 8 ) n in which the variables have the following meaning, independently of one another: R 1 hydrogen, C 1 -C 24 -alkyl, R 9 —C(═O)—, R 9 —NH—C(═O)—, polyalcohol residue; R 8 hydrogen, C 1 -C 24 -alkyl, R 9 —C(═O)—, R 9 —NH—C(═O)—; R 2 to R 7 —(CH 2 ) 2 —, —(CH 2 ) 3 —, —(CH 2 ) 4 —, —CH 2 —CH(CH 3 )—, —CH 2 —CH(CH 2 —CH 3 )—, —CH 2 —CHOR 10 —CH 2 —; R 9 C 1 -C 24 -alkyl; R 10 hydrogen, C 1 -C 24 -alkyl, R 9 —C(═O)—; A —C(═O)—O—, —C(═O)—B—C(═O)—O—, —C(═O)—NH—B—NH—C(═O)—O—; B —(CH 2 ) t —, optionally substituted arylene; n 1 to 8; s 0 to 500; t 1 to 12; u 1 to 5000; v 0 to 5000; w 0 to 5000; x 1 to 5000; y 0 to 5000; z 0 to 5000 c) and optionally at least one other monomer by adding a free-radical initiator system, wherein the free-radical initiator system is a solution consisting of a free-radical initiator and a liquid polyethylene glycol having a molecular weight between 88 and 1000 which polyethylene glycol is liquid at room temperature.