| 摘要 |
1484017 Cellular polymers E I DU PONT DE NEMOURS & CO 19 Nov 1974 [19 Nov 1973] 53657/73 Addition to 1400921 Heading C3R [Also in Division B5] Cellular polymers are prepared by curing an amine-curable polymer or prepolymer with a curing agent which is a complex of 4,41-methylene dianiline and a salt selected from the nitrites and halides (other than the fluorides) of sodium and lithium and sodium cyanide and/or a complex of racemic 2,3-di-(4-aminophenyl)butane and a halide (other than the fluoride) of sodium, potassium, rubidium or caesium, in the presence of a chemical blowing agent. Most preferably the amine-curable polymer or prepolymer is a polyurethane prepolymer, particularly one derived from polytetramethylene ether glycol and 2,4-tolylene diisocyanate. The curing agent is preferably a complex of 4,4<SP>1</SP>-methylene dianiline and sodium chloride or lithium chloride. The blowing agent may be a compound containing two mutually linked nitrogen atoms, e.g. a hydrazide, azide, azo compound or nitroso compound and most preferably is N,N<SP>1</SP>-dimethyl - N,N<SP>1</SP> - dinitrosoterephthalamide. Curing takes place by elevating the temperature above the dissociation temperature of the curing agent and blowing agent. |
