| 摘要 |
PURPOSE:To obtain a modified polyurethane giving a sealant having low modulus and excellent weatherability, by reacting a polymeric polyol composed of a polyol and an ethylenic unsaturated monomer with an organic polyisocyanate and an isocyanato organic silane. CONSTITUTION:The objective modified polyurethane is produced by reacting (A) a polymeric polyol composed of (a) a polyol (preferably a combination of a high-molecular weight polyol such as polyether polyol and a low-molecular weight polyol such as ethylene glycol) and (b) an ethylenic unsaturated monomer [preferably acrylonitrile, [methlacrylic acid (salt) and their derivatives] with (B) an organic polyisocyanate (preferably hexamethylene diisocyanate, etc.) and (C) an isocyanato organic silane (preferably gamma-isocyanatopropyltrietho xysilane, etc.). The molar ratio of the OH of the component A to the NCO of the components B and C is preferably 1:1. The reaction is carried out prefer ably by reacting the component A with the component C, and reacting the product with the component B.
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