| 摘要 |
1447887 Rubber cross-linking systems LORD CORP 12 Nov 1973 [13 Nov 1972] 52367/73 Headings C3E and C3P Unsaturated elastomers are cured with a composition comprising a urethane cross-linking agent and a maleimide cross-linking agent, the weight ratio of the maleimide agent to the urethane agent being from 4 : 1 to 0À1 : 5. The urethane agent may be derived from a polyisocyanate or polyisocyanate dimer and a substituted or unsubstituted nitrosophenol. Preferred maleimides are N,N<SP>1</SP>-linked bismaleimides joined directly at the nitrogen atoms or in which the nitrogen atoms are joined to and separated by an intervening divalent radical. Examples are given of curing (a) a polychloroprene formulation using the diurethane formed from 2,4- toluene diisocyanate dimer and 4-nitroso-2,6- xylenol (DUT 2 X) and m-phenylene bis-maleimide (HVA-2); (b) a natural rubber formulation containing zinc dimethyl dithiocarbamate (ZDMC), DUT 2 X and HVA-2; (c) a natural rubber formulation containing, optionally, antioxidants, and ZDMC, HVA-2 and DUT 2 X or the phenol-blocked monourethane of 2,4- toluene diisocyanate and p-nitroso-m-cresol; (d) a butadiene-acrylonitrile rubber formulation DUT 2 X, HVA-2 and ZDMC; (e) a natural rubber formulation containing ZDMC, the diurethane from p-nitroso-m-cresol and 2,4- toluene diisocyanate dimer and HVA-2; (f) a natural rubber formulation containing ZDMC, HVA-2 and the monourethane of 2,4-toluene diisocyanate and p-nitroso-m-cresol; (g) a natural rubber formulation containing ZDMC, HVA-2 and a mixture of the diurethane of 2,4- toluene diisocyanate and p-nitrosophenol and a polyaryl polyisocyanate derived from N,N<SP>1</SP>- methylene diphenyl diisocyanate, N,N<SP>1</SP>- p-phenylene bismaleimide may be used in place of the HVA-2. |
