Patent ID: 7872083

Claim:
A polymer comprising an amphoteric monomer represented by the following general formula (I) and a cationic monomer represented by the following general formula (II) as the essential constituent monomers: wherein, R 1 represents a hydrogen atom or a methyl group; R 2 and R 3 each independently represent an alkyl or alkoxy group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a phenyl group, or a —(CH 2 CH 2 O) n R 7 group, wherein n is an integer of 1 to 50; and R 7 represents a hydrogen atom, an alkyl group, or an alkoxy group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a phenyl group; R 4 represents an alkylene group having 1 to 3 carbon atoms; A represents an oxygen atom or NR 8 , wherein R 8 represents a hydrogen atom, an alkyl group, or an alkoxy group having 1 to 4 carbon atoms, a phenyl group, or a —(CH 2 CH 2 O) n R 9 group, wherein n is an integer of 1 to 50; R 9 represents a hydrogen atom, an alkyl group, or an alkoxy group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a phenyl group; and B represents an alkylene group having 1 to 4 carbon atoms, R 5 and R 6 each independently represent a hydrogen atom or an alkyl group, or an alkoxy group having 1 to 4 carbon atoms; and Y − represents a monovalent inorganic or organic anion.