Patent ID: 7706658

Claim:
A copolymer containing a repeating unit represented by the following formula (1), and at least one of a repeating unit represented by the following formula (2-1) and a repeating unit represented by the following formula (2-2): wherein R 1 and R 2 represent an alkyl group or an aryl group, provided that at least one of R 1 and R 2 contains a fluorine atom and R 1 and R 2 are not an alkyl group containing a group represented by —(CX 2 ) n —X in which X is a halogen atom and n is an integer of 7 or more, wherein R 3 represents an alkyl group, an aryl group, an alkoxy group or an amino group, and R 4 represents an alkyl group, wherein R 5 and R 6 each represent a hydrogen atom, an alkyl group or an aryl group; wherein the repeating unit represented by formula (2-2) is introduced by any one of methods (1), (2) or (3); wherein, method (1) is a method of introducing a fumarate having a siloxane unit represented by formula (6) as a monomer into a side chain, wherein, at least one of R 7 and R 8 is a substituent represented by the following formula SU-1 wherein, R 9 to R 13 each represents a hydrogen atom, an alkyl group or an aryl group; L 1 represents a connecting group having from 1 to 20 carbon atoms; n is an integer of 0 or 1; p is an integer from 30 to 500; and when only one of R 7 and R 8 is SU-1, the other represents an alkyl group or an aryl group; method (2) is a method of introducing into a side chain using a vinyl monomer having a siloxane unit, the vinyl monomer having a siloxane unit being at least one of a compound represented by formula (7), a compound represented by formula (8), or a compound represented by formula (9): wherein R 14 represents a hydrogen atom, a methyl group or a trifluoromethyl group; R 9 to R 13 each represents a hydrogen atom, an alkyl group or an aryl group; L 1 represents a connecting group having from 1 to 20 carbon atoms; n is an integer of 0 or 1; and p is an integer from 30 to 500; method (3) is a method of introducing into a main chain using an initiator having a siloxane unit-containing azo initiator having a repeating unit represented by formula (10): wherein, R 15 to R 18 each represents an alkyl group or an aryl group; and x is an integer of from 30 to 500.