GB270293A - A process for producing insoluble colouring materials in a state of fine dispersion - Google Patents

Abstract

270,293. I. G. Farbenindustrie Akt.- Ges. April 28, 1926, [Convention date]. Emulsions, making. - In the production of solid insoluble colouring materials in, or conversion of such materials into a state of fine dispersion, trihydroxyethylamine is used as an emulsifying agent in association with gelatinizable substances or water-soluble gums. Glue, gelatine, casein, agar-agar, gum arabic, hydrolyzed starch or the like may be employed as gelatinizable substances or gums. The process is applicable to inorganic or organic solid insoluble colouring materials, e.g. pigments, lampblack, or blanc fixe, and may be employed in grinding organic pigments with heavy spar or the like. In one example, the yellow pigment obtained by coupling diazotized 5-nitro-4-toluidine and acetoacetic anilide is ground in the dry state with powdered glue and trihydroxyethylamine; the product when made into a paste with water forms highly-dispersed suspensions which may be used for staining paper pulp or printing wall-papers. The glue may be replaced by other of the substances mentioned above, and the dispersing substances or their solutions may be added to an aqueous paste of the pigment which is then dried and ground. The subsequent grinding may be omitted if the paste is dried in such a manner as to yield the dried product in powdered form. In another example, a mixture of glue and trihydroxyethylamine, dissolved in water, is added to an alkaline solution of #-naphthol, which is then coupled with diazotized p-nitraniline, the pigment is precipitated in finely-divided form. The process may also be carried out in the presence of the usual substrata. Specification 258,551 is referred to. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the replacement of the trihydroxyethylamine by soaps, saponines, turkey-red oil, cholates, sulphite cellulose waste liquor, or the sodium salt of benzylaniline sulphonic acid or of alkylated, e.g. propylated or butylates naphthalene sulphonic acids, and the invention is applied to solid materials in general, sulphur being additionally specified. This subjectmatter does not appear in the Specification as accepted.