Verfahren zur Herstellung flexibler Beschichtungen

摘要

1,125,718. Coated sheet material. BADISCHE ANILIN-& SODA FABRIK, A.G. 21 Jan., 1966 [22 Jan., 1965], No. 2808/66. Heading B2E. [Also in Division C3] Sheet materials containing cellulose are coated with a sub-coat by applying aqueous dispersions of mixtures of (1) copolymers A of 80-98% by weight of vinylidene chloride and 2-20% by weight of copolymerisable monoethylenically unsaturated compounds and (2) polymers B of ethylenically unsaturated compounds having a glass transition temperature of +10‹ to -55‹C, the amount of polymers B being 10-65% of the weight of the sum of the polymers A and B in the mixture, drying the sub-coat and thereafter applying as top-coat aqueous dispersions of a copolymer of 80-98% by weight of vinylidene chloride and 2-20% by weight of a copolymerisable monoethylenically unsaturated compound and drying the top-coat. Compounds copolymerisable with the vinylidene chloride in copolymers A may be esters of acrylic and/or methacrylic acid and monohydric aliphatic alcohols containing 1-8 carbon atoms in the alcohol radical, and vinyl chloride, acrylonitrile, methacrylonitrile, styrene, vinyl esters of aliphatic monocarboxylic acids having 2-12 carbon atoms, such as vinyl acetate and propionate, acrylamide, methacrylamide, acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, the monoamides and N-substituted monoamides of said acids, esters and monoesters of these acids, and aliphatic monohydric and aliphatic monohydric alcohols containing 1-8 carbon atoms, maleic anhydride and itaconic anhydride. Polymers B may be copolymers containing 40-90% by weight of esters of acrylic acid and/or methacrylic acid with monohydric alcohols containing 2-8 carbon atoms and 10-60% of other conventional monoethylenically unsaturated compounds polymerisable by free radical mechanisms, such as methyl methacrylate, methyl acrylate, styrene, acrylonitrile, vinyl chloride or vinylidene chloride Copolymers of n-butyl acrylate and of butadiene with styrene, acrylonitrile or esters of ethylenically unsaturated carboxylic acids may be used. The proportions of monomers must be such as to provide the specified glass transition temperature. Various suitable copolymers are identified in the Examples. Emulsifiers may be added to the dispersions such as surface active salts of sulphonated ethenoxylated alkylphenols or fatty alcohols. Heat and light stabilizers, anti-foams,. thickeners and plasticizers may be added. Coating may be by means of doctor knives, rollers or shreading means, flooding means, houring or dipping. Drying may be with infrared rays or preheated air. The substrate may be paper or laminates of paper with metal foils such as aluminium foils.