POLYURETHANE, COMPOSITION FOR FORMATION OF POLISHING LAYERS THAT CONTAINS SAME, PAD FOR CHEMICAL MECHANICAL POLISHING, AND CHEMICAL MECHANICAL POLISHING METHOD USING SAME

摘要

A polyurethane prepared by reacting a mixture which contains at least (A) a diisocyanate, (B) a polyol, and (C) a chain extender, characterized in that: the polyol (B) has a number-average molecular weight of 400 to 5,000; the chain extender (C) contains (C1) a compound of general formula (1) and (C2) a compound of general formula (2); the number-average molecular weights of the compounds (C1) and (C2) are each less than 400; and the M1/(M1+M2) value is 0.25 to 0.9 wherein M1 is the molar amount of the compound (C1) and M2 is that of the compound (C2). HO-(CR1R2)2m+1 - OH ... (1) HO-(CR3R4)2n - OH ... (2)