| 摘要 |
1,240,747. Polyurethanes. FARBENFABRIKEN BAYER A.G. 1 Dec., 1969 [12 Dec., 1968], No. 58579/69. Heading C3R. Elastic polyurethanes which can be crosslinked by high energy light and/or heat are prepared by reacting (a) a polyester containing at least two hydroxyl groups and having a M.W. of 800 to 5000, (b) a diisocyanate and (c) an aliphatic glycol having a M.W. below 500 and containing at least one group in the molecule. The polyurethanes may be prepared in a one-stage reaction or by any of the prepolymer processes known in the art. Conventional polyesters and diisocyanates are used. In the examples, the compound (c) used has the formula Other compounds (c) which may be used are 4,4<SP>1</SP>-bis-(#-hydroxyethyl ether)-distyrylketone; 4,4<SP>1 </SP>- bis - (# - hydroxyethyl ether) - distyrylcyclohexylketone and 4,4<SP>1</SP>-bis-(#-hydroxyethyl ether)-distyryl-cyclopentylketone. The glycols (c) may be used in admixture with known glycol chain lengthening agents. |
