| 摘要 |
1402650 Ethylene copolymer-waxblends E I DU PONT DE NEMOURS & CO 1 Nov 1972 [1 Nov 1971] 50411/72 Heading C3P [Also in Division C5] Gel free blends of (1) a paraffin, microcrystalline, Fischer-Tropsch or polyolefin wax and (2) an ethylene/vinyl ester copolymer containing 10 to 45 weight per cent of vinyl ester, the initial viscosity and melt strength of which blends have been increased by free radical initiated cross-linking, may be prepared by mixing the molten wax/copolymer blend with a free radical initiator having a half-life greater than 10 minutes at 200‹ F. and less than 5 minutes at 350‹ F., below the decomposition temperature thereof and raising the temperature of the mixture above said decomposition temperature. The copolymer may be derived from vinyl acetate, formate, propionate, butyrate, palmitate or stearate, optionally with up to 10 weight per cent of vinyl chloride, styrene or acrylic or methacrylic acid or esters. The initiator may be a peroxide or azo compound. The rate and extent of crosslinking may be controlled by promoters, e.g. divinyl terephthalate, or inhibitors, e.g. divinyl diphenyl silane. The compositions may contain modifying resins, e.g. rosin, hydrogenated rosin and esters thereof, polyterpenes, vinyl toluene copolymers and pentaerythritol resins. Examples describe the crosslinking of blends of refined paraffin wax and ethylene/vinyl acetate copolymers with (1-22, 26 and 27) t.-butyl peracetate, optionally in the presence of (23-25 and 32)α-methylstyrene/vinyl toluene copolymer and (28) divinyl terephthalate; with (29- 31)α,α<SP>1</SP>-bis- (t.-butylperoxy) diisopropylbenzene; and with (33) dicumyl peroxide in the presence of triallyl cyanurate. |
