Examples of the polyhydric hydroxy compounds include polyether polyols such as polyalkylene glysocls, polyamine polyols, polymer polyols, polytetramethylene glycol and the like, polyester polyols such as adipate polyols, phthalate polyols, polycaprolactone polyols, polycarbonate polyols and the like, and polyhydric alcohols such as trimethylol propane, butanediol and the like.