Patent ID: 8710168

Claim:
A polymer comprising structural units of formula I, structural units of formula II and structural units of formula IIIa: wherein R 1 and R 2 are the same or different and each represent a C 8 to C 22 alkyl group; wherein R 3 represents —OCOR 6 , —COOR 15 , —COOH, or a C 1 to C 22 alkyl group, and R 6 represents a C 1 to C 22 alkyl group; wherein R 4 is hydrogen, —COOH or —CH 2 COOR 16 ; wherein R 15 and R 16 are the same or different and each represent a C 8 to C 22 alkyl group; wherein R 5 is hydrogen or methyl; wherein X represents a group of formula IV: wherein R 7 represents hydrogen or a C 1 to C 8 alkyl group, R 8 represents a C 1 to C 8 alkyl group, m is an integer from 1 to 10, and n is an integer from 1 to 30.