| 摘要 |
1340112 Olefin terpolymer elastomers E I DU PONT DE NEMOURS & CO 19 April 1971 [2 April 1970] 26043/71 Headings C3P and C3Q Branched elastomeric EPDM polymers having less than 30% gel, a Williams plasticity of 60 to 100 and an inherent viscosity of at least 2À2 at less than 30% gel, may be prepared by mixing an EPDM polymer having 0À1 to 2 gram-moles of carbon to carbon double bonds per kilogram of elastomer and a Williams plasticity of 20 to 60 with a promoter selected from 0À00125 to 0À00780 gram atoms of sulphur, an organic polysulphide yielding 0À00125 to 0À00780 gram atoms of sulphur and 0À0005 to 0À003 gram equivalents of an organic peroxide or hydroperoxide, or mixtures thereof, per 100 grams of copolymer, and heating. Preferred EPDM polymers are ethylene/propylene/1,4-hexadiene copolymers. Preferred organic polysulphides are 4,4<SP>1</SP> - dithiodimorpholine and dipentamethylene thiuram hexasulphide. Preferred peroxides are t-butyl perbenzoate, dicumyl peroxide and 2,5- dimethyl - 2,5 - di - t - butylperoxy - hexane and -hexyne. The process may be effected batchwise or continuously, preferably in the absence of processing oils, and the products compounded with diene elastomers, e.g. natural rubber, styrene/butadiene rubber, polyisoprene and neoprene, to give ozone resistant vulcanizable compositions. In examples ethylene/propylene/ 1,4-hexadiene copolymers prepared by polymerizing in tetrachloroethylene in the presence of hydrogen and catalysts formed from vanadium tetrachloride or oxychloride and diisobutyl aluminium chloride are modified by mixing and heating with (1) sulphur, (2) 2,5-dimethyl- 2,5 - di - t - butylperoxy - hexane and (3) 4,4<SP>1</SP>-dithiodimorpholine, the products being compounded with natural rubber and vulcanized. |
