| 摘要 |
1,147,571. Polyurethanes. FARBENFABRIKEN BAYER A.G. 4 Jan., 1968 [7 Jan., 1967], No. 645/68. Heading C3R. Polyurethanes are prepared by reacting a prepolymer derived from an excess of α,α<SP>1</SP>-di- (p-isocyanatephenyl)-p-diisopropyl benzene and a polyhydric alcohol with a compound having a M.W. of 800 to 10,000 and containing reactive hydrogen atoms. The reaction is suitably carried out in the presence of a solvent which yields clear solutions of the prepolymers. Such solvents may be ketones, mixtures of ketones with glycol ether acetates, mixtures of glycol ether acetates with ethyl acetate and butyl acetate or mixtures of ketones with ethyl acetate and butyl acetate. Exemplified polyhydric alcohols are glycerol; 1,1,1-trimethylolpropane and pentaerythritol. The compound of M.W. 800 to 10,000 may be a polyester, polyesteramide or polyether. |
