| 摘要 |
PURPOSE:To form a polyurethane desirable for the production of a leathery composite sheet having good sliminess and being free from the deterioration of the sliminess with time by using a specified polycarbonatediol and a specified polylactonediol and an organic diisocyanate as the principal components. CONSTITUTION:A polyurethane mainly consisting of a polymerdiol unit (A-1) derived by removing the two hydrogen atoms of the two terminal alcoholic hydroxyl groups from a polycarbonatediol comprising a unit derived by removing the two hydrogen atoms of the two hydroxyl groups from at least one 8-10C alkanediol selected from the group consisting of 1,8-octanediols and 1,9- nonanediols each of which may be substituted with a methyl group and a carboxyl unit of formula I, a polymerdiol unit (A-2) derived by removing the two hydrogen atoms of the two terminal alcoholic hydroxyl groups from a polylactonediol comprising a beta-methyl-delta-varelolactone unit of formula II as a structural repeating unit and an organic diisocyanate unit (B) of formula II (wherein R is a bivalent organic group). |
