METHOD OF PRODUCING MULTICELLULAR MULTILAYER THERMOPLASTIC SYNTHETIC RESIN FILMS

摘要

1,240,586. Paper-like thermoplastic synthetic resin films. SEKISUI KAGAKU KOGYO K.K. 4 July, 1969 [6 July, 1968], No. 33964/69. Heading B5B. [Also in Divisions B2 and C3] A process for the production of paper-like thermoplastic synthetic resin films which comprises melt mixing and kneading a composition comprising 100 parts by weight of an olefin resin, 1 to 100 parts by weight of at least one additional resin selected from styrene, acrylate, acetal, phenoxy, vinyl chloride, vinyl acetate and amide resins, and 10 to 300 parts by weight of at least one inorganic filler, shaping the composition into a sheet and stretching the sheet biaxially at 100‹ to 170‹ C., preferably at a draw ratio in at least one direction higher than 1À5 : 1. The composition may also contain not more than the total weight of olefin resin, additional resin and inorganic filler of one or more rubber selected from polyurethane, styrene-butadiene, acrylonitrile-butadiene, polybutadiene and propylene oxide rubbers. The inorganic filler may be selected from diatomaceous earth, powdered hydrous silica, talc, kaolin, zeolites, mica powder, asbestos powder, calcium carbonate, magnesium carbonate, calcium sulphate, clay, silica powder, alumina, magnesium sulphate, barium sulphate, zinc sulphide, titanium oxide and zinc oxide. The further treatment to improve the properties required for use as a paper may comprise making at least one of the surfaces more polar by flame, electric discharge or oxidant treatment, high energy or ultra-violet irradiation or applying a polar resin either as a monomer or in a solvent. Alternatively the surface may be contacted with a solvent for the olefin resin, which may contain a polar resin and may contain one or more inorganic filler, and thereafter evaporating the solvent. As an alternative to evaporating the solvent the film may be treated with a non-solvent for the olefin resin which is compatible with the solvent. Alternatively the film surface may be treated with a solvent for the additional resin which is a non-solvent for the olefin resin to elute some of the additional resin. Alternatively, inorganic fillers may be dispersed on at least one surface of the film either by dispersing heated fillers or fillers wetted with a solvent for the olefin resin and thereafter heat-compressing the film or by fixing the fillers on the surface with a binder. The film may be impregnated with an ink-drying promoter. The paper-like films so produced have a multi-cellular multi-layered structure and show good surface and mechanical strength, abrasion resistance, graphic properties and printability, flexibility, weatherability, flame and chemical resistance.