GB414862A - Improvements in the production of chlorinated rubber - Google Patents

Abstract

Chlorinated rubber is produced by the admixture of solutions of rubber and of chlorine, for example in carbon tetrachloride, in contact with water, and the resulting emulsion of water in chlorinated rubber may be inverted to form an aqueous dispersion of chlorinated rubber by dilution of the emulsion with water. The rubber may be natural or synthetic, compounded or uncompounded, and purified or in the natural condition. The term "rubber" includes balata and guttapercha. Separation of the chlorinated rubber as an aqueous dispersion can be effected by adding to the washed emulsion of chlorinated rubber an alkali e.g. ammonia, and a protective colloid e.g. casein, agitating in a colloid mill and removing the solvent by evaporation.ALSO:A method of producing chlorinated rubber is characterized by the admixture of solutions of rubber and of chlorine in contact with water. The rubber may be natural or synthetic, compounded or uncompounded, and purified or in the natural condition. The term "rubber" includes balata and guttapercha. The solvent for the rubber and for the chlorine may be carbon tetrachloride. Either or both of the solutions may be cooled before and after being mixed; also the water may be introduced cold-e.g. as crushed ice. The water may contain an oxidizing agent, such as hydrogen peroxide or a permanganate or a hypochlorite, for the purpose of recovering chlorine from hydrogen chloride formed by the action of chlorine on the rubber. It is stated that any hydrogen chloride ultimately formed is substantially retained by solution in the water. Into the resulting emulsion of water in chlorinated rubber may be introduced fillers, pigments, &c. The emulsion may also be washed with fresh water, and inversion thereof-i.e. the production of an aqueous dispersion of chlorinated rubber-may be effected by dilution of the emulsion with water. The rubber solvent may be recovered by decantation or distillation with steam or both, the residual chlorinated rubber being in the form of a porous mass, friable when cold; or separation of the chlorinated rubber as a fine powder can be effected by stirring the emulsion vigorously with ethyl alcohol in the cold or, as an aqueous dispersion, by adding to the washed emulsion of chlorinated rubber an alkali-e.g. ammonia-and a protective colloid-e.g. casein-, agitating in a colloid mill and removing the solvent-say, carbon tetrachloride-by evaporation. Five examples are given.