| 摘要 |
PURPOSE:To obtain polyurethane excellent in water repellency, mold release and heat resistance and extremely low in water absorption, by reacting a polyol component with a specified isocyanate component. CONSTITUTION:An isocyanate component is obtained by mixing 0.1-100pts.wt. isocyanate compound having silicon in the molecule, such as a compound of formula I or II [wherein n is 1-4, m is 1-3, R is an (un)saturated aliphatic or aromatic hydrocarbon group unsubstituted or substituted with methyl, ethyl, vinyl or phenyl and A is a bivalent hydrocarbon group such as alkylene, O, S or the like] with, optionally, 100pts.wt. monoisocyanate compound such as ethyl isocyanate or polyisocyanate such as tolylene diisocyanate. This component is reacted with a polyol having at least two alcoholic hydroxyl groups in the molecule (e.g., polyester polyol) in the presence of, optionally, a chain extender, crosslinking agent and 0.01-5wt% (based on polyol) catalyst.
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