GB783790A - - Google Patents

Abstract

783,790. Ethylene graft polymers. BRITISH CELLOPHANE, Ltd. Dec. 5, 1955 [Dec. 9, 1954], No. 35735/54. Class 2 (6). Ethylene graft polymers are prepared by polymerizing one or more monomers of the formula where R 1 and R 2 are hydrogen or halogen atoms or alkyl, cycloaliphatic, aromatic, nitrile, ester, amide, ketone or ether radicals, with polythene in solution or dispersion and which has previously been activated by treatment with one or more free radical generating substances. The monomers may be vinyl acetate, methyl vinyl ketone, styrene, methyl, ethyl, butyl or isobutyl acrylate or methacrylate, acrylonitrile, methacrylonitrile, vinyl chloride or vinylidene chloride. The free radical generating substances may be benzoyl, lauroyl or phthaloyl peroxide, cumene or tertiary butyl hydroperoxide, azo-diisobutyronitrile or a water-soluble persulphate. The polythene may be prepared by polymerization of gaseous ethylene and should preferably have an average molecular weight of at least 20,000. Activation and polymerization may be carried out in solution in organic solvents, e.g. toluene, petroleum ether, trichloroethylene and benzene, and the product recovered by precipitation, e.g. with methanol or ethanol, or in dispersion in a non-solvent, e.g. aqueous media containing salts of long-chain alkyl sulphates such as sodium dodecyl sulphate, and the product recovered by coagulation, e.g. with aluminium sulphate solution. Preferably polythene solutions are heated with free radical generating substances for 5 minutes to 1 hour and, after cooling, if necessary, the monomers added and the polymerization effected, optionally under pressure. Films may be produced by extrusion or casting from hot solutions and may be heat sealed to plain and moisture-proof regenerated cellulose films. Specifications 679,562, 694,408, 718,515, 764,297 and Canadian Specification 494,421 are referred to.