| 摘要 |
1497673 Stretched porous polymer films MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 23 Dec 1974 [28 Dec 1973] 55647/74 Heading C3C A biaxially - oriented open - pored film comprising (i) 100 parts by weight of a thermally stretchable high molecular weight polymer having a crystallinity of at least 30% and (ii) 1 to 300 parts by weight of a blending material which will exist in a molten state in at least a portion of the hot stretching temperature range of said high molecular weight polymer, wherein said film includes a number of flattened voids having their largest dimensions in a plane parallel to the surface of the film and having a mean diameter in that plane of 0À1 to 100 microns and fine arc-shaped fibre structures, having a mean diameter of 0À01 to 50 microns, on the surface of the film. Preferably when (i) is polyolefine, (ii) may be a polyolefin other than (i), silicone resin, silicone oil, polyamide resin, olefin oligomer, wax, fatty acid or an amide thereof having at least 11 carbon atoms or metallic soap; if (i) is isotactic polypropylene, (ii) is polyethylene, if (i) is a polyester, (ii) is selected from polyolefin resin, polyamide resin, polyvinyl chloride, polystyrene and polycarbonate; if (i) is polyamide resin, (ii) is selected from polyvinyl resin, polyester resin, polyvinylidene resin, polyether resin and polyacrylic resin; if (i) is polyvinylidene resin, (ii) is selected from polyvinyl resin, polyether resin and polyamide resin. In the Examples the mixtures which were biaxially stretched were (1) low density polyethylene and isotactic polypropylene; (2) as (1) plus high density polyethylene; (3) polyester copolymer and nylon 66; (4) polyethylene terephthalate, polystyrene and silica; (5) polyvinylchloride and polyvinylidene fluoride; to yield products which had 500 to 5,000 voids/mm in the thickness direction and 2,000 to 20,000 voids/sq. mm in the plane direction and a void ratio (volume of void to volume of film) of 5 to 80%. The specific gravity of (3) and (4) was 0À85 and 0À97 respectively. |
