| 摘要 |
1,274,878. Polyurethanes. FARBENFABRIKEN BAYER A.G. 14 July, 1969 [29 July, 1968], No. 35266/69. Heading C3R. Polyurethanes are prepared by reacting with simultaneous or subsequent cross-linking (a) a diisocyanate, (b) a compound which has a M.W. of up to 500 and which contains at least two groups which are reactive with isocyanates and (c) a compound which contains at least two hydroxyl groups and has a M.W. of 800 to 50,000 and which contains a polyaddition product of one or more primary or secondary diamines, hydrazines or acyl hydrazines with one or more diisocyanates in approximately equimolar proportions. The polyaddition produet may be prepared in situ in the compound (c). Compounds (a) and (b) are those conventionally used in the polyurethane art. Compound (c) is suitably an adipic acid based polyester but may also be a polyether. Numerous compounds for preparing the polyaddition products are listed. Specifically exemplified are those derived from diisocyanato - diphenylmethane and 4,41-diaminodiphenyl-methane or toluylene diamine in situ in an ethylene glycol/ adipic acid polyester. Uses.-Hydrolysis resistant sealing materials, sole materials for shoes, gear-wheel belts and gear wheels, wear-resistant linings and valve seatings. |
