Patent ID: 7217179

Claim:
A polishing pad having a polishing layer made of a polyurethane or polyurethane-urea, wherein the polyurethane or polyurethane-urea comprises a cured reaction product of a mixture of an isocyanate-terminated urethane prepolymer A and a chain extender B which has two or more active hydrogen-containing groups capable of reacting with an isocyanate group in the molecule and satisfies the following conditions “a” and “b”: a. the chain extender consists of 50 to 100 wt % of a chain extender having a number average molecular weight of 300 or less and 50 to 0 wt % of a chain extender having a number average molecular weight higher than 300, b. the chain extender consists of 20 to 100 wt % of a chain extender having three or more active hydrogen-containing groups in the molecule and 80 to 0 wt % of a chain extender having two active hydrogen-containing groups in the molecule; and the ratio of the storage elastic modulus at 30° C. to the storage elastic modulus at 60° C. of said polishing layer is 2 to 15, and the ratio of the storage elastic modulus at 30° C. to the storage elastic modulus at 90° C. of said polishing layer is 4 to 20.