Polyurethane and the polishing layer forming composition containing the same, as well as chemical mechanical polishing pad and chemical mechanical polishing method using the same

Polyurethane according to the present invention comprises at least (A) a diisocyanate, (B) a polyol, a polyurethane obtained by reacting a mixture containing, and (C) a chain extender, wherein (B) the polyol the number average molecular weight is 400 to 5,000, the (C) chain extender, (C1) a compound represented by the following general formula (1), compounds represented by (C2) represented by the following general formula (2) When, wherein the number average molecular weight of the compound (C1) and the compound (C2) is less than 400, the number of moles of the number of moles of the compound (C1)