Patent GB-987404-A (GB)
Title: Coated paper products
IPC: D21H19/50
Filed: 1961-03-27
Abstract: A copolymer used in coating paper (see Division B2) comprises 15 to 40% by weight of units of acrylic or methacrylic acid or both and 60 to 85% by weight of units of one or more esters of acrylic or methacrylic acid or both with an alcohol having from one to four carbon atoms, and has an average molecular weight of at least 50,000. It may be made by an emulsion process, using a free-radical initiator and a chain-regulator such as a long-chain alkyl mercaptan, an alcohol, carbon tetrachloride, tetrachlorethylene, bromotrichloromethane or methally chloride. In an example (Experiment A) an emulsion is prepared from sodium lauryl sulphate, water, ammonium persulphate, ethyl acrylate, methyl methacrylate, methacrylic acid and bromotrichloromethane. This emulsion is added to a reaction vessel containing water, ferrous sulphate and tert-butyl hydroperoxide. Sodium metabisulphite is added, and the temperature rises.  Further increments of emulsion and sodium metabisulphite are added from time to time and finally a further quantity of tert.-butyl hydroperoxide is added.  The product is cooled and filtered and is an emulsion of the copolymer of methacrylic acid, methyl methacrylate and ethyl acrylate.  Compositions contain these copolymers as their ammonium or amine salts together with a mineral pigment, of which at least a part is clay, and an auxiliary binder.  The following binders are used in the examples: (1a) the copolymer of Experiment A and a copolymer of 80% ethyl acrylate, 3% itaconic acid and 17% methyl methacrylate; (1b) a copolymer of acrylic acid, ethyl acrylate and 2-ethylhexyl acrylate and a copolymer of ethyl acrylate and methacrylacid and the other ingredients as before; the copolymer of Experiment A and (2a) alpha-protein, (2b) casein, (2c) a copolymer of 90% vinyl acetate, 5% ethyl acrylate and 5% acrylic acid, (3a) a copolymer of butadiene and styrene, or (3b) natural rubber latex; (2d) a copolymer of methacrylic acid, methyl methacrylate and methyl acrylate, and alpha-protein; (4) a copolymer of methylacrylic acid, methyl methacrylate and ethyl acrylate, and the second polymer of Example (1a).  In each case there are also present clay, sodium hexamethaphosphate and more than enough ammonia to convert the free carboxylic groups to their ammonium salts.  After application, the coatings are heated to drive off ammonia.  Specifications 802,039, 802,967 and U.S.A. Specification 2,790,735 are referred to.ALSO:Paper or paperboard is coated with a composition comprising finely divided mineral pigment, of which at least a part is clay, and two binders. The first binder is a copolymer of 15-40% by weight of acrylic or methacrylic acid or both and 60-85% by weight of one or more esters of acrylic or methacrylic acid with an alcohol having from one to four carbon atoms, the copolymer having an average molecular weight of at least 50,000.  The second binder is a protein which is soluble in an aqueous alkaline solution, or a water-insoluble and alkali-insoluble addition polymer.  The pigment may be wholly of clay, or partly of clay and partly of calcium carbonate, blanc fixe, talc, titanium dioxide, coloured lakes and toners, ochre, carbon black, graphite, aluminium powder or flake, chrome yellow, molybdate orange, toluidine red or copper phthalocyanines.  The second binder may be casein or alpha-protein; natural or synthetic rubber, e.g. a butadiene-styrene copolymer; a polymer of butadiene, styrene, isobutylene, ethylene, vinyl acetate, vinyl chloride, vinylidene chloride, acrylonitrile, methacrylonitrile or an ester of acrylic or methacrylic acid with an alkanol having from one to eight carbon atoms; a copolymer of an alkyl acrylate in which the alkyl group has one to four carbon atoms with up to 7% by weight of a copolymerizable mono-ethylenically unsaturated acid or an amide of acrylic or methacrylic acid; or a copolymer of vinyl acetate, methyl or ethyl acrylate and acrylic, methacrylic or itaconic acid.  The coating may be applied to the paper with the copolymer in the form of its ammonium or amine salt, and the coating subsequently heated to drive off ammonia or volatile amine.  It may be applied to paper after drying or conditioning or both, or after it has been partially dried in the course of manufacture. After coating, the sheet is dried and may then be calendered, printed and overcoated, after printing, with wax or lacquer.. Specifications 802,039, 802,967, and U.S.A. Specification 2,790,735 are referred to.ALSO:Paper or paperboard is coated with a composition comprising finely divided mineral pigment, of which at least a part is clay, and two binders.  The first binder is a copolymer of 15 to 40% by weight of acrylic or methacrylic acid or both and 60 to 85% by weight of one or more esters of acrylic or methacrylic acid with an alcohol having from one to four carbon atoms, the copolymer having an average molecular weight of at least 50,000.  The second binder is a protein which is soluble in an aqueous alkaline solution, or a water-insoluble and alkali-insoluble addition polymer.  The pigment may be wholly or clay, or partly of clay and partly of calcium carbonate, blanc fixe, talc, titanium dioxide, coloured lakes and toners, ochre, carbon black, graphite, aluminium powder or flake, chrome yellow, molybdate orange, toluidine red or copper phthalocyanines.  The second binder may be casein or alpha-protein; natural or synthetic rubber, e.g. a butadiene-styrene copolymer; a polymer of butadiene, styrene, isobutylene, ethylene, vinyl acetate, vinyl chloride, vinylidene chloride, acrylonitrile, methacrylonitrile or an ester of acrylic or methacrylic acid with an alkanol having from one to eight carbon atoms; a copolymer of an alkyl acrylate in which the alkyl group has one to four carbon atoms with up to 7% by weight of a copolymerizable mono-ethylenically unsaturated acid or an amide of acrylic or methacrylic acid; or a copolymer or vinyl acetate, methyl or ethyl acrylate and acrylic, methacrylic or itaconic acid.  The coating may be applied to the paper with the copolymer in the form of its ammonium or amine salt, and the coating subsequently heated to drive off ammonia or volatile amine.  It may be applied to paper after drying or conditioning or both, or after it has been partially dried in the course of manufacture. After coating, the sheet is dried and may then be calendered, printed and overcoated, after printing, with wax or lacquer. Specifications 802,039, 802,967 and U.S.A.  Specification 2,790,735 are referred to.