These compounds can be used singly or in admixture of two or more kinds.As the polyester diol and the polyester amide diol, there can be mentioned, for example, those compounds obtained by subjecting the following two kinds of compounds to a dehydration-condensation reaction:at least one kind of compound selected from known dicarboxylic acids (e.g. succinic acid, adipic acid, sebacic acid, azelaic