| 摘要 |
1,154,916. Block polymer-polyethylene films. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. 22 Sept., 1966 [24 Sept., 1965], No. 42359/66. Heading C3P. An elastomeric film comprises (1) 100 parts by weight of a block copolymer of the formula A-B-A where each A is an independently selected polymer block of a monovinyl aromatic hydrocarbon, the said polymer block A having an average molecular weight between 8000 and 45,000, and B is a polymer block of a conjugated diene hydrocarbon, the said polymer block B having an average molecular weight between 35,000 and 150,000, the total block A content being less than 38% by weight of the block copolymer and (2) 15 to 400 parts by weight of a polyethylene. The preferred polyethylenes are those having a density at 23‹ C. between 0À90 and 0À93 grams per cm.<SP>3</SP> and a melt index between 0À2 and 30 at 190‹ C. The films may be formed by conventional blowing, extruding or casting techniques from compositions of the polymers, which compositions may be formed by conventional milling, tumbling, or solution blending techniques. The films may be used for wrapping, coating or lining articles. In the example blends of polyethylene with a block copolymer of polystyrene (9000)-polybutadiene (45,000) - polystyrene (9000) are prepared by tumbling pellets in a cement mixer, and films prepared from the blends by extrusion. |
