Patent GB-1106063-A (GB)
Title: Latices of vinylidene chloride polymers
Inventor: TROFIMOW ALEX
IPC: C08F214/08
Filed: 1965-03-09
Abstract: Latices of polymers consisting of 80 to 94 weight per cent of vinylidene chloride units, 1 to 20 weight per cent of methyl acrylate units, 1 to 10 weight per cent of acrylonitrile units and also units of at least one other copolymerizable monomer, said latices containing 3.0 to 4.25 weight per cent of emulsifier, based on the weight of polymer, may be prepared by dispersing the monomers in water with the aid of the emulsifying agent, polymerizing the monomers with the aid of a polymerization initiator, adding further monomer and emulsifying agent in substantially constant proportions and discontinuing the polymerization when the total solids content in the reaction zone is 40 to 50 weight per cent.  Specified other monomers are methyl methacrylate, methacrylonitrile, ethyl acrylate and butyl acrylate.  Specified emulsifiers are sodium alkyl and aryl sulphates and alkylaryl sulphonates.  Specified catalysts are hydrogen peroxide, persulphates, acyl peroxides, organic per acids and peresters, and organic hydroperoxides, optionally together with sodium sulphite, sucrose or ferrous gluconate; or azo diisobutyronitrile.  Emulsifier coupling agents, e.g. acetic acid, glycerol, acrylic acid, methanol and dioctyl sulphosuccinate. The polymers may be used for making films; and dispersions, optionally thickened with sodium alginate, karaya gum, hydroxyethyl cellulose or polyvinyl alcohol, and organic solvent solutions may be used for coating.  Examples describe the preparation of copolymers of vinylidene chloride, methyl acrylate, methyl methacrylate and acrylonitrile with and without acrylic acid in the presence of sodium dodecylbenzene sulphonate.ALSO:Compositions for coating substrates such as paper, paper boards and polymer films comprise copolymers of 80 to 94 weight per cent of vinylidene chloride, 1 to 20 weight per cent of methyl acrylate, 1 to 10 weight per cent of acrylonitrile, units of at least one other monomer, preferably methyl methacrylate or methacrylonitrile, said copolymer being derived by emulsion polymerisation in the presence of 3.0 to 4.25 weight per cent of emulsifier based on the copolymer.  Coating may be effected by air knife coater, size press, trailing blade, transfer roll, reverse roll, roller coater, gravure, bead coat, metering bar, spray coater or curtain coater, using an aqueous latex of the copolymer, optionally thickened with sodium alginate, karaya gum, hydroxyethyl cellulose or polyvinyl alcohol, or an organic solution of the copolymer, e.g. in tetrahydrofuran, methyl ethyl ketone and toluene. Polymer films may be sub-coated to improve adhesion, but coatings may be applied directly to films of polar polymers, e.g. polycarbonates, polyesters and polyvinyl chloride. In examples clay coated paperboards are coated with aqueous latices of copolymers of vinylidene chloride, methyl acrylate, acrylonitrile together with methacrylonitrile, methyl methacrylate or methyl methacrylate and acrylic acid, prepared by copolymerisation in aqueous dispersion in the presence of sodium dodecylbenzene sulphonate.