Patent ID: 8012224

Claim:
A polishing composition comprising a copolymer, water and an abrasive, wherein the copolymer has a constitutional unit expressed as the following formula (I) and at least one constitutional unit selected from the group consisting of constitutional units expressed as the following formulas (II) to (III): wherein in the formula (I), R 1 is a hydrogen atom or a methyl group, R 2 is a C 1 to C 4 alkyl group, AO is a C 1 to C 8 oxyalkylene group, p is 0 or 1, n is an average number of total AO units added and ranges from 6 to 300, and the proportion of an oxyethylene group in (AO) n is 80 mol % or more; in the formula (II), R 3 is a hydrogen atom or a methyl group, X is an oxygen atom or an NH group, and R 4 is a C 4 to C 30 alkyl group or a C 6 to C 30 aryl group; and in the formula (III), R 5 is a hydrogen atom or a methyl group, R 6 is a hydrogen atom or a C 1 to C 3 alkyl group, AO is a C 2 to C 4 oxyalkylene group, m is an average number of total AO units added and ranges from 3 to 150, and the proportion of an oxypropylene group and an oxybutylene group in (AO) m is 80 mol % or more, wherein the content of water in the polishing composition is 75 wt % or more, and the content of the copolymer in the polishing composition is 0.001 to 3 wt %.