| 摘要 |
PURPOSE:To provide a sealant which has no toxicity and excellent handleability, exhibiting excellent water cutoff properties for a prolonged period of time and which comprises a soft polyurethane elastomer prepd. by mixing a urethane prepolymer having a particular isocyanate terminal with water. CONSTITUTION:A polyalkylene oxide contg. 20-60wt% prim. alkylene oxide units in its molecule, prepd. by polymn. of a prim. alkylene oxide and a sec. alkylene oxide, is reacted with an org. polyisocyanate, thereby preparing a urethane prepolymer (A) having an isocyanate terminal. The prepolymer (A) is mixed with water (B) in a wt. ratio of A to B of 1:0.3-5, thereby preparing a soft polyurethane elastomer. The sealant is comprised of this elastomer. With respect to the sealant, it is possible to blend filaments of an org. fiber inactive to isocyanate groups with the soft polyurethane elastomer, or to integrate, by lamination etc., a woven or non-woven fabric composed of the above org. fiber with the elastomer.
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