Patent GB-1107957-A (GB)
Title: Process for coating and coated articles
Inventor: GRENLEY DALLAS GEORGE
IPC: C08J7/052
Filed: 1966-03-02
Abstract: A non-crystalline vinylidene chloride copolymer the form of an aqueous, coating dispersion which is not film-forming at 25 DEG  C. comprises (a) from 80 to 87% vinylidene chloride; (b) 8 to 20% methyl, ethyl acrylate, methyl methacrylate, acrylonitrile or a mixture thereof; and (c) not more than 9% vinyl chloride, butadiene or an alkyl acrylate the alkyl group of which contains from 2 to 22 carbon atoms provided that when the (b) monomer is ethyl acrylate the alkyl group contains at least 3 carbon atoms, or mixture thereof. Preferably the interpolymer contains 2 to 5% of (c) monomers.  The polymers may be prepared by batch or continuous polymerization of the monomer mixture in aqueous suspension, preferably without the addition to the suspension of soap or other emulsifiers.  The dispersions may be modified by the addition of emulsifiers, thickners, dyes, pigments, fillers, slip agents such as talc, wax. The wax may be present in the proportion 2 to 10% by weight and such waxes may be prepared by an emulsion inversion technique.  Latexes of polymers having the following compositions are disclosed, all parts being by weight: 8 parts vinylidene chloride, 13 parts acrylonitrile, 2 parts 2-ethyl hexyl acrylate; 10 parts acrylonitrile, 5 parts butyl acrylate, 85 parts vinylidene chloride; 14 parts acrylonitrile, 6 parts butyl acrylate, 80 parts vinylidene chloride; 15 parts methyl methacrylate 15 parts octyl acrylate, 80 parts vinylidene chloride; 7 parts methyl acrylate, 9 parts octyl acrylate, 84 parts vinylidene chloride, 13 parts acrylonitrile, 2 parts octyl acrylate, 85 parts vinylidene chloride; 10 parts acrylonitrile, 6 parts octyl acrylate, 2 parts vinyl chloride, 83 parts vinylidene chloride; 10 parts ethyl acrylate, 3 parts butyl acrylate, 87 parts vinylidene chloride; 10 parts acrylonitrile, 6 parts octadecyl acrylate, 2 parts butadiene, 83 parts vinylidene chloride. To 1000 parts of the latex is added 22 parts of a 10% aqueous ammonia solution, 125 parts of a carnauba wax dispersion (20% wax), 14.3 parts aqueous talc dispersion, 5 parts of 10% solution of sodium oleate.ALSO:A process for coating a substrate comprises depositing on the surface thereof a vinylidene chloride copolymer in the form of an aqueous dispersion which is not film-forming at 25 DEG C, drying the aqueous dispersion and fusing or sintering the copolymer, the copolymer being non-crystalline and containing (a) from 80 to 87% vinylidene chloride (b) 8 to 20% methyl, ethyl acrylate, methyl methacrylate, acrylonitrile or a mixture thereof, and (c) not more than 9% vinyl chloride, butadiene or an alkyl acrylate the alkyl group of which contains from 2 to 22 carbon atoms provided that when the (b) monomer is ethyl acrylate the alkyl group contains at least 3 carbon atoms, or mixture thereof. Preferably the interpolymer contains 2 to 5% of (c) monomers.  The polymers may be prepared by batch or continuous polymerization of the monomer mixture in aqueous suspension, preferably without the addition to the suspension of soap or other emulsifiers.  The dispersions may be modified by the addition of emulsifiers, thickeners, dyes, pigments, fillers, slip agents such as talc, wax. The wax may be present in the proportion 2 to 10% by weight and such waxes may be prepared by an emulsion inversion technique.  The coating may be dried by heat applied by conduction, radiation, or combination thereof.  The substrate may be coated or uncoated paper prepared from fibres other than wood cellulose; metal foils, e.g. aluminium, gold foil; synthetic resin films, foils, e.g. polyethylene, polypropylene, branched and linear copolymers thereof, alkenyl aromatic resin, e.g. solid homopolymers of styrene, alpha-methyl-, ortho-methyl-, meta-methyl-, para-methyl-, ar-ethyl-styrene, ar-vinyl xylenes, ar-chlorostyrenes, ar-bromostyrenes, or copolymers of two or more such compounds with minor proportions of polymerizable olefinic compounds such as divinylbenzene, methyl methacrylate, acrylonitrile, polymers and copolymers of methyl methacrylate, e.g. vinylidene chloride/methyl methacrylate copolymer, thermoplastic polymers and copolymers of vinyl chloride, thermoplastic ester and other derivatives of cellulose, e.g. cellulose acetates, propionate, acetate butyrate and ethyl cellulose, hydrophobic thermoplastic resins such as chlorinated polyolefines, copolymers of vinylidene chloride with one or more of vinyl chloride, acrylates linear polyesters, polycarbonamides. The substrate may be coated at 5 to 30 DEG C by brushing, dipping, spraying, or using transfer rolls.  Latexes of polymers having the following compositions are disclosed, all parts being by weight:-8 parts vinylidene chloride, 13 parts acrylonitrile 2 parts 2-ethyl hexyl acrylate; 10 parts acrylonitrile, 5 parts butyl acrylate, 85 parts vinylidene chloride; 14 parts acrylonitrile, 6 parts butyl acrylate, 80 parts vinylidene chloride; 15 parts methyl methacrylate 15 parts octyl acrylate, 80 parts vinylidene chloride; 7 parts methyl acrylate, 9 parts octyl acrylate, 84 parts vinylidene chloride, 13 parts acrylonitrile, 2 parts octyl acrylate, 85 parts vinylidene chloride; 10 parts p  acrylonitrile, 6 parts octyl acrylate, 2 parts vinyl chloride, 83 parts vinylidene chloride; 10 parts ethyl acrylate, 3 parts butyl acrylate, 87 parts vinylidene chloride; 10 parts acrylonitrile, 6 parts octadecyl acrylate, 2 parts butadiene, 83 parts vinylidene chloride.  Portions of the latex are dried by radiant heat to form a film employed for evaluation purposes.  To 1,000 parts of the latex is added 22 parts of a 10% aqueous ammonia solution, 125 parts of a carnauba wax dispersion (20% wax), 14.3 parts aqueous talc dispersion, 5 parts of 10% solution of sodium oleate.  The formulations are cast on to oriented polystyrene, polypropylene, polyethylene film, a film of a copolymer comprising 85% vinylidene chloride, 15% vinyl chloride, ethyl cellulose, cellulose acetate butyrate film, polyethylene phthalate film, polycaprolactam, Kraft paper, aluminium foil, steel foil, birch veneer.  The resultant coatings are block-free, readily heat sealable and exhibit improved barrier properties.  To promote adhesion of the coatings, the substrate may be surface treated by corona discharge, ozonization, sulphonation, and prime coats.