Patent GB-1415006-A (GB)
Title: Coated synthetic film and a method of producing the same
IPC: C08J7/043
Filed: 1972-10-27
Abstract: 1415006 Coated film NIPPON KAKOH SEISHI KK 27 Oct 1972 [28 Oct 1971] 49603/ 72 Heading B2E  A coated film of up to 300 microns thickness comprises a plastics film having a thickness of more than 15 microns coated on one side or both sides with 15-40 grams per square metre of an opaque, printable, pigment-containing coating comprising two layers, the top layer containing for each 100 parts of pigment from 10-20 parts by solid content of a latex binder, from 0.2-0.7 parts of a dispersing agent and 2-20 parts of satin white, and a prime layer containing for each 100 parts of pigment from 28-100 parts by solid content of a latex binder, from 0.2-0.7 parts of dispersing agent and 2-20 parts of satin white. The coated film may be produced by coating a plastics film having thickness greater than 15 microns on one side or both sides with 5-15 grams by solid content per square metre of an aqueous, pigmentcontaining composition having a viscosity of 50-1000 cps, the composition containing for each 100 parts of pigment 28-100 parts by solid content of a latex binder, 0.2-0.7 parts of dispersing agent and 2-20 parts of satin white and thereafter drying at a temperature of 70C to a temperature which is 50C above the softening point of the plastics film for 10 seconds to 2 minutes, then again coating the resulting coated film over the coated side with 10-25 grams by solid content per square metre of an aqueous, pigment-containing composition having a viscosity of 50-1000 cps, the composition containing for each 100 parts of pigment 10-20 parts by solid content of a latex binder, 0.2-0.7 parts of dispersing agent and 2-20 parts of satin white and thereafter drying at a temperature of 70C to a temperature which is 50C above the softening point of a plastics film for 10 seconds to 2 minutes. The drying of each layer may be effected in two steps, the first step being that from 70C to a temperature which is 50C above the softening point of the plastics film until the viscosity of the coating is 1800-2000 cps, the second step being at 20-60C for 3-10 minutes. In a modification the top layer of the coated film contains for each 100 parts of pigment 10-26 parts by solid content of the latex binder, 0.2-0.7 parts of dispersing agent, 0.5-3.9 parts of a non- ionic surfactant, 0.1-2.6 parts of a heat-sensitive coagulating agent and 2-20 parts of satin white. The coated film may also contain three or more layers, at least one of the intermediate layers being the same as the prime layer. The plastics films may be polyvinyl chloride, copolymers of vinyl chloride with vinyl esters such as vinyl acetate and with vinylidene chloride, styrene polymers and copolymers, polyethylene, polypropylene, polyamides, polyesters, polyurethanes, natural and synthetic rubbers, polycarbonates, cellulose di- or tri-acetate. The films may be plasticised, mono- or bi-axially oriented. Suitable pigments are kaolin, calcium carbonate, talc, titanium dioxide. The latex binder may be an acrylic polymer, modified styrene-butadiene rubber, modified methyl methacrylate-butadiene rubber, styrene-methylmethacrylate-butadiene rubber, acrylonitrilebutadiene rubber, ethylene vinyl acetate copolymer. In a modification of the invention, up to about 10% of the latex binder in each layer may be replaced with a water-soluble polymeric binder such as casein, starch, modified starch, polyvinyl alcohol. The heat-sensitive coagulating agent may be any one or a mixture of salts of divalent lead, zinc, magnesium, calcium, strontium, and barium and trivalent chromium and aluminium in combination a member selected from sulphate, phosphate, nitrate, isothionate, and halogen ions, polyvinyl or methyl ether, polypropylene glycol, cationic surface active agents having both a hydrophobic group selected from higher alkyl amines, higher alkyl halides and higher fatty acids, and a hydrophilic group consisting of pyridine, inorganic acids, ethylene oxide, ethanolamines, asymetrical diamines, aminoethanol amine, polyethylene-polyamines. Suitable non- ionic surfactants are ethylene oxide adducts of higher alcohols, alkyl phenols, fatty acids, polyhydric alcohol-fatty acid esters, higher alkyl amines, fatty acid amides, fatty oils, polypropylene glycol. The preferred dispersing agents are phosphates. The plastics films may be coated using a roller, blade or knife-coater.