| 摘要 |
<p>1423239 Polyurethane foams SCOTT PAPER CO 14 March 1973 [20 March 1972] 12183/73 Heading C3R Polyurethane foams are prepared in a one-shot process by reacting together (a) a polyol, (b) a polyisocyanate, the isocyanate groups of which are attached to aliphatic (including cycloaliphatic) groups, (c) an aromatic polyisocyanate, (d) a blowing agent and (e) a catalyst for urethane formation, the aliphatic isocyanate index being equal to 5 to 40 and the aromatic isocyanate index being equal to 60 to 95. The polyol (a) may be a polyether or polyester polyol. Suitable polyisocyanates (b) are acyclic polyisocyanates, cycloaliphatic polyisocyanates and aralkylene polyisocyanates. Conventional aromatic polyisocyanates, e.g. TDI, are used. Foam stabilizers and U.V. light absorbing compounds are preferably incorporated in the reaction mixture.</p> |
