| 摘要 |
Synthetic resin compositions comprise an intimate admixture of a vinyl chloride polymer having a weight average molecular weight of 50,000 to 500,000 and an ethylene-vinyl acetate copolymer containing 35 to 85% by weight of vinyl acetate and having a weight average molecular weight of at least 15,000. Up to 30 wt. per cent of vinyl acetate may be 40 to 60 wt. per cent of vinyl acetate may be used to yield rigid compositions having an impact strength greater than 1 ft.-lb. per inch of notch (Izod) while 20 to 50 wt. per cent of a copolymer containing 60 to 85 wt. per cent of vinyl acetate may be used to yield flexible compositions, the copolymer acting as a plasticizer, either alone or in conjunction with conventional plasticizers, e.g. di-butyl, -amyl, -hexyl, -octyl, -(2-ethylhexyl) or -butyl-glycol phthalate; methyl or ethyl phthalyl ethyl glycollate; butyl phthalyl butyl glycollate; tri-tolyl, -butyl or -octyl phosphate; dihexyl sebacate and dioctyl adipate. The vinyl chloride polymer may be a homo- or copolymer having a weight average molecular weight of 50,000 to 500,000 and a number average molecular weight of 25,000 to 150,000. Other ingredients present in exemplary compositions are a dibutyl tin sulphur compound, tin mercaptide, stearic acid, 2,6-di-t-butyl-4-methylphenol, titanium dioxide and wax. |
