GB518704A - Improvements in and relating to the production of emulsions and of flexible films - Google Patents

Abstract

518,704. Vinyl polymerization products. RENFREW, A., GATES, W. E. F.,and IMPERIAL CHEMICALINDUSTRIES, Ltd. Sept. 2, 1938, No. 3676/39. Divided out of 50] ,810. [Class 2 (iii)] Emulsions, from which continuous films are obtainable by evaporation, are obtained by subjecting an aqueous emulsion containing one or more monomeric esters of methacrylic acid, the molecular weight or average molecular weight of the alcohol radicle or radicles of which lies between 20 and 80, to polymerizing conditions, i.e., to the action of heat, light, or polymerizing catalysts, or two or more of these agencies, with the introduction before, during or after polymerization of a proportion of plasticizer between 80 per cent. and a minimum lying between 27 and 1 per cent. and varying with the molecular weight or the average molecular weight of the alcohol radicle or radicles substantially in accordance with the ccrve A.F shown on the drawing, the percentages being calculated upon the combined weights of the polymerized ester or esters and the plasticizer. A certain minimum proportion of plasticizer is required to give flexible films by evaporation of the emulsion and the points A to F on the curve correspond to experimental determinations of the minimum amounts of plasticizer in the case of methyl, ethyl, propyl, butyl, amyl and hexyl methacrylates. Suitable plasticizers are dibutyl phthalate, tricresyl phosphate, triphenyl phosphate and cellulose ester lacquer plasticizers. Emulsifying agents may be present, and the emulsion may be thickened by the addition of sodium alginate, a water-soluble cellulose ether, or gum tragacanth. A small amount of a water-miscible solvent, e.g., methyl alcohol, may be added to the ester before polymerization. The emulsions may be used also for treating and binding textiles, dressing leather, paper or wood, coating metal, or in the preparation of water paints. In examples, an aqueous emulsion of (1) and (6) tricresyl phosphate and ethylmethacrylate with or without propyl methacrylate, and (2) to (4) dibutyl phthalate and propyl, butyl or amyl methacrylate, is heated in the presence of ammonium persulphate, and (5) dibutyl phthalate and butylmethacrylate is heated in the presence of benzoyl peroxide. Specifications 358,534, 411,860, 437,446, and 501,810 are referred to.