| 摘要 |
1,248,181. Segmented polyurethane elastomers. FARBENFABRIKEN BAYER A.G. 22 Jan., 1970 [22 Jan., 1969(2); 24 March, 1969], No. 3112/70. Heading C3R. [Also in Division C2] Linear, segmented polyurethane elastomers are prepared by reacting an isocyanate terminated prepolymer containing 2 isocyanate groups with a chain lengthening agent, at least 55 mole per cent of which is a semi-carbazide amine of the formula wherein R is -(CH 2 ) y - (y=2 to 6); mcr pphenylene, wherein X=0, 1 or 2. The prepolymers may be prepared from conventional diisocyanates and polyethers, polyesters or polycarbonates. The semicarbazide amines may be used in admixture with known chain lengthening agents. The chain lengthening reaction is suitably carried out in an inert organic solvent. Particularly good semicarbazide amine chain lengthening agents are #-semicarbazide ethylamine, 4- aminophenyl - semicarbazide, 3 - aminophenylsemicarbazide, 4 - aminobenzyl - semicarbazide and 4 - aminodiphenylether - 4<SP>1</SP> - semicarbazide. The semicarbazide amines may be used in the form of their carbonates. In a typical example a polyester derived from adipic acid, 1,6-hexane diol and 2,2-dimethyl propane diol is reacted with N,N-bis-(#-hydroxypropyl)-methylamine and diphenylmethane - 4,4<SP>1 </SP>- diisocyanate in chlorobenzene to form a prepolymer which is reacted with #-semicarbazido-ethylamine carbonate in dimethylformamide. The elastomer solution is pigmented and reacted further with hexane-1,6-diisocyanate and wet-spun to form filaments. |
