Verfahren zur Behandlung der Oberflaeche von Polyolefinen zur Erhoehung ihrer bindenden Eigenschaften

摘要

989,377. Coated polyolefin film. LOWE PAPER CO. Oct. 6, 1961 [Oct. 17, 1960], No. 36082/61. Heading B2E. A method of preparing a material comprising a coated polyolefin comprises subjecting a polyolefinic surface to a surface activation treatment and then applying to the activated surface a hydrophilic non-pigmentedcoating composition such that the weight of the coating when dry is within the range 0À07-1À4 pounds per 1000 square feet of the polyolefinic surface. The surface activation treatment may be an oxidation treatment such as by exposure to an open flame, exposure to ozone, chlorine, certain acids and/or electron bombardment. The coating may be applied in the form of a film. The polyolefin film, e.g. polyethylene, polypropylene, polyalphabutylene, polyisopropyl propylene or polyisopropyl butene, may be united with a backing. The material may be prepared by extruding polyolefin and applying a non- pigmented hydrophilic coating composition within the prescribed limits to a surface of the hot polyolefin on its emergence from the extrusion orifice. Polyethylene may be extruded at a temperature of 610 ‹F. or more. As shown, the polyolefin may be extruded on to a backing 36, 361, e.g. paper, boxboard; cloth, foil and "Cellophane" (Registered Trade Mark), and may be activated by a gas burner 40, Fig. 1. The coating composition applied by 42, 45, 421, 451 from both 44, 441, or by an air-knife coater, may be a nonpolymerizing, polar, hydrophilic aqueous phase coating composition, e.g. one containing one or more proteins such as gelatin or casein, soya protein and/or carbohydrates such as starch, hydroxy ethyl ether derivative of cornstarch, carboxymethyl cellulose, and "Methocel" (Registered Trade Mark) as a principal constituent. The material may be shaped, e.g. as a packaging material, and may be overprinted with printing ink or coated with adhesive, e.g. dextrin or starch adhesives, on parts of the coating. The hydrophilic coating may incorporate synthetic polymers, e.g. butadiene-styrene, butadiene-acrylonitrile, polyacrylates such as polymers of ethyl acrylate, ethyl methacrylate, polyvinyl alcohol, acetate and chloride, vinyl acetate-acrylate and vinyl chloride-vinyl acetate copolymers. Specifications 902,664 and 903,350 are referred to.