| 摘要 |
A method of providing a composite sheet material which has soft and pliable hand characteristics, despite being dense, and also high resistance against discoloration and deterioration. The method comprises impregnating and/or coating a fibrous sheet with a mixture of (A) a polyurethane elastomer containing a sterically hindered amino group within its molecular chain, (B) a compound selected from the group consisting of a polybasic acid and its halide, metal salt and ammonium salt, wherein one or more hydrogen atoms remain unreacted, which amount of (B) is within the range of 0.8-5 molar equivalents relative to the sterically hindered amino group, and (C) a solvent for the polyurethane elastomer (A), and subjecting the resulting material to wet coagulation. |
