Perfectionnements apportés aux émulsifiants et à leur mise en oeuvre

The invention comprises the barium and cadmium salts of a surface-active agent which is an ester composed of carbon, hydrogen and oxygen alone, the molecule of which contains at least 2 ester linkages and 1 to 3 free carboxyl groups, the remainder of the molecule being composed of aliphatic or cycloaliphatic hydrocarbon groups, said groups comprising at least 2 lipophilic groups each containing 12 to 30 carbon atoms, the ratio between the total number of carbon atoms and the number of free carboxyl groups being between 45:1 and 80:1 and the molecular weight being between 600 and 2000. The suitable surface-active agents are those described in Specification 930,371. The cadmium salts are made by adding an aqueous solution of cadmium acetate to a suspension of the surface-active agent in an aqueous lye followed by washing and drying the resultant precipitate. The barium salts are made similarly, barium chloride being used instead of cadmium acetate. Examples describe the preparation of the barium and cadmium salts of the products of Examples 7, 21, 22 and 23 of Specification 930,371.ALSO:The invention comprises polymers of vinyl chloride containing a small amount of a barium and/or cadmium salt of a surface-active agent which is an ester composed of carbon, hydrogen and oxygen alone, the molecule of which contains at least 2 ester linkages and 1 to 3 free carboxyl groups, the remainder of the molecule being composed of aliphatic or cycloaliphatic hydrocarbon groups, said groups comprising at least 2 lipophilic groups each containing 12 to 30 carbon atoms, the ratio between the total number of carbon atoms and the number of free carbonyl groups being between 45:1 and 80:1 and the molecular weight being between 600 and 2000 (see Division C2). The surface-active agents are those described in Specification 930,371. The polymers of vinyl chloride are heat-stabilized by the incorporation therein of the barium and cadmium salts of the surface-active agents. In Example 1 a plasticized, heat-stabilized film is made by working 100 parts of polyvinylchloride and 50 parts of dioctyl phthalate on a roller mill at 170 DEG C. with 2 parts of the cadmium salt of the reaction product of an isomerised soyabean oil, maleic anhydride and stearyl alcohol described in Example 7 of Specification 930,371. The barium salt may be used instead of the cadmium salt. Examples 2 and 3 are similar but use the barium or cadmium salts of the products of Examples 21-23 of Specification 930,371