| abstract |
The invention aims at providing a polyurethane foam which has a uniformly foamed structure, attains improvement in the flatness of a polished surface and flatting efficiency, is prolonged in serviceable life as compared with those of the prior art, and is suitably usable as a polishing pad. This aim is attained by a polyurethane foam made of a thermoplastic polyurethane which is produced by reacting a polymeric polyol with an organic diisocyanate and a chain-lengthening agent, contains nitrogen atoms resulting from isocyanate in an amount of 6 wt% or above, and exhibits a dynamic viscoelasticity at 50°C (E'50) of 5 x 10?9 dyn/cm2¿ or above, and having a density of 0.5 to 1.0 g/cm3, a foam size of 5 to 200 νm, and a hardness (JIS-C hardness) of 90 or above. |