Polishing composition

摘要

A polishing composition that prevents a peripheral portion of the surface of a substrate for a magnetic disk from being excessively polished. A first polishing composition according to the present invention includes a compound, which is represented by the following general formula. The letter X represents a residue of polyether polyol. The letter m represents a number equal to the number of hydroxyl groups in one molecule of the polyether polyol. The letter Y represents a divalent hydrocarbon group. The letter Z represents a residue of a monovalent compound, which has an active hydrogen atom. The letter n represents an integer number of at least three. A second polishing composition according to the present invention includes a polymer, which has a monomer unit derived from isoprene sulfonic acid or its salt. These polishing compositions also comprise an abrasive, a polishing accelerator and water.