Patent GB-514037-A (GB)
Title: Improvements relating to compositions suitable for coating and impregnating
IPC: C08J3/07
Filed: 1938-02-17
Abstract: 514,037. Emulsions; coating-compositions. MAY, W. Feb. 17, 1938, No. 5018. Convention date, Feb. 17, 1937. [Classes 1 (i) and 95] [Also in Groups IV and VIII] Emulsions or dispersions of resins, natural or artificial rubber, chlor-rubber, cellulose esters and cellulose ethers are prepared by dissolving the material in an organic solvent which is non-miscible or of limited miscibility with water, adding an aqueous precipitant, and incorporating an organic substance capable of swelling in water and of thus forming a colloidal dispersion, together with sufficient wetting agent to stabilize the emulsion, the quantity of swellable substance being less than would be required to stabilize the emulsion in the absence of the wetting agent. Specified organic substances capable of swelling in water are casein, animal or vegetable glue, gelatine, starch and carob bean flour, and these are usually present in amounts of less than 1 per cent. of the material to be dispersed. Fillers, such as metal powders, bran flour, and cork flour, and softening agents, may be added. Pigments and soluble colouring materials may be present. The emulsions may be used as coatings, impregnants and adhesives, for application to paper, fabrics, wood, cork, leather, celluloid, metal and moulded articles, and fibres, and give a matt finish. According to examples: (1) a poly-vinyl ester, a phenolformaldehyde resin, or an acrylic acid polymer is dissolved in benzene or toluene, and a solution containing casein and ammonia, or containing glue, calcium chloride and alphanaphthalene sodium sulphonate, is added, together with, in either case, the wetting agent known under the Registered Trade Mark " Nekal." Tricresyl phosphate may be added as a softening agent; (2) a mixture of casein, triethanolamine, " Nekal " and water, is stirred and a xylene solution of an oil-modified phthalic acid-glycerin resin is then poured in with stirring; (3) a solution of celluloid and colophony in ethyl or butyl acetate, with the addition of tricresyl phosphate and blown castor oil, is poured with vigorous stirring into an ammoniacal solution of casein containing " Nekal " ; (4) chlor-rubber is dissolved in toluene, and tricresyl phosphate and castor oil added. The mixture is stirred into an ammoniacal solution of casein, containing " Nekal," or into a glue or gelatine solution containing alpha-naphthalene sodium sulphonate or calcium chloride ; (5) a solution of polyvinyl acetate in toluene, containing tricresyl phosphate, is added to an aqueous solution of carob bean flour, containing a wetting agent. In all the above examples, the quantity of casein or analogous substance used is less than would be required to stabilize the emulsion or dispersion, if the wetting agent were not present, but the presence of the wetting agent ensures a stable product. According to the Specification as open to inspection under Sect. 91, the water-swellable substance need not be organic, and Bentonite is specified. This subject-matter does not appear in the Specification as accepted.