Patent ID: 7291682

Claim:
A method for the preparation of a comb or star copolymer, said method comprising a) polymerizing in a first step, two or more epoxy group containing monomers to obtain a polyether, wherein at least one monomer is of formula (II) wherein R 1 , R 2 , R 3 and R 4 are independently of each other C 1 -C 4 alkyl; R 5 is hydrogen or C 1 -C 4 alkyl; R′ 6 is hydrogen and R 6 is H, OR 10 , NR 10 R 11 , —O—C(O)—R 10 or NR 11 —C(O)—R 10 ; R 10 and R 11 independently are hydrogen, C 1 -C 18 alkyl, C 2 -C 18 alkenyl, C 2 -C 18 alkinyl or C 2 -C 18 alkyl which is substituted by at least one hydroxy group or, if R 6 is NR 10 R 11 , taken together, form a C 2 -C 12 alkylene bridge or a C 2 -C 12 -alkylene bridge interrupted by at least one O atom; or R 6 and R′ 6 together are both hydrogen, a group ═O or ═N—O—R 20 wherein R 20 is H, straight or branched C 1 -C 18 alkyl, C 3 -C 18 alkenyl or C 3 -C 18 alkinyl, which may be unsubstituted or substituted, by one or more OH, C 1 -C 8 alkoxy, carboxy, C 1 -C 8 alkoxycarbonyl; C 5 -C 12 cycloalkyl or C 5 -C 12 cycloalkenyl; phenyl, C 7 -C 9 phenylalkyl or naphthyl which may be unsubstituted or substituted by one or more C 1 -C 8 alkyl, halogen, OH, C 1 -C 8 alkoxy, carboxy, C 1 -C 8 alkoxycarbonyl; —C(O)—C 1 -C 36 alkyl, or an acyl moiety of a α,β-unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms; —SO 3 − Q + , —PO(O − Q + ) 2 , —P(O)(OR 2 ) 2 , —SO 2 —R 2 , —CO—NH—R 2 , —CONH 2 , COOR 2 , or Si(Me) 3 , wherein Q + is H + , ammnonium or an alkali metal cation; or R 6 and R 6 ′ are independently —O—C 1 -C 12 alkyl, —O—C 3 -C 12 alkenyl, —O—C 3 -C 12 alkinyl, —O—C 5 -C 8 cycloalkyl, —O-phenyl, —O-naphthyl, —O—C 7 -C 9 phenylalkyl; or R 6 and R′ 6 together form one of the bivalent groups —O—C(R 21 )(R 22 )—CH(R 23 )—O—, —O—CH(R 21 )—CH 22 —C(R 22 )(R 23 )—O—, —O—CH(R 22 )—CH 2 —C(R 21 )(R 23 )—O—, —O—CH 2 —C(R 21 )(R 22 )—CH(R 23 )—O—, —O-o-phenylene-O—, —O-1,2-cyclohexyliden-O—, R 21 is hydrogen, C 1 -C 12 alkyl, COOH, COO—(C 1 -C 12 )alkyl or CH 2 OR 24 ; R 22 and R 23 are independently hydrogen, methyl, ethyl, COOH or COO—(C 1 -C 12 )alkyl; R 24 is hydrogen, C 1 -C 12 alkyl, benzyl, or a monovalent acyl residue derived from an aliphatic, cycloaliphatic or aromatic monocarboxylic acid having up to 18 carbon atoms; and R 7 and R 8 are independently hydrogen or C 1 -C 18 alkyl; and at least one monomer is an epoxy group containing monomer different from formula (II); where the weight ratio of the monomer of formula (II) to the sum of the other monomers is from 99:1 to 1:99; and in a second step b) adding to the polymer obtained in step a) at least one ethylenically unsaturated monomer or oligomer, heating the resulting mixture to a temperature where cleavage of the nitroxylether bond occurs and radical polymerization starts; and polymerizing to the desired degree.