Patent GB-692654-A (GB)
Title: Improvements in the production of water-insoluble, non-swellable organic pigments
IPC: C09B67/20
Filed: 1951-03-02
Abstract: Water-insoluble, non-swelling, organic pigments are made by treating natural products of starch or albuminous character in aqueous suspension with solutions of free methylol compounds in which the methylol groups are directly attached to nitrogen atoms in the presence of small amounts of acid-reacting agents and then heating the products at 110-150 DEG  C. for a short time.  Specified methylol compounds are dimethylol urea, tetramethylol acetylene diurea, methylol derivatives of carboxylic acid amides and urethanes. Acid-reacting agents specified are strongly diluted mineral acids or their ammonium salts and readily hydrolysable salts, e.g. aluminium chloride.  Potato starch and casein are specified natural products. The first stage is effected at ordinary or slightly elevated temperatures for about 15-45 minutes and the product is filtered off, dried and finally heated at 110-150 DEG  C.  The pigments may be coloured with dyestuffs or impregnated with bactericides, plasticizers, capillary-active substances, astringent agents or water-repellent agents.  They may be used in toothpastes, wound dusting powder, foot, face and body powders, as pigments for the paper, leather or textile dyeing or printing-trades and in the lacquer industry.  They may be admixed with other inorganic or organic pigments.  In examples: (1) potato flour, suspended in water, is treated with dimethylol urea in the presence of ammonium nitrate for about 20-30 minutes the product is filtered off, dried at about 70 DEG  C. and heated for about 15 minutes at 120 DEG  C.  The final product may be impregnated with water-soluble fatty derivatives, e.g. the formate of the monostearic acid ester of triethanolamine, and dyestuffs or other substances may be added to the treatment bath together with the methylol compounds provided that an acid reaction is maintained; (2) casein is treated with tetramethylol acetylene diurea under the conditions of (1) the final drying being at 140 DEG C. and the product may be impregnated with disinfecting agents, e.g. quaternary ammonium compounds, or dyed with basic dyestuffs, e.g. "Greifswalder Blau"; and in (3) rice starch is treated with tetramethylol acetylene diurea in the presence of ammonium or zinc chlorides and the reaction product of 9 mols. of ethylene oxide with 1 mol. of fatty alcohols containing about 8-14 C atoms per mol. under the reaction conditions of (1), the final heating being at 140 DEG C.; the ethylene oxide reaction product may be replaced by the formate of triethanolamine monostearic acid ester.ALSO:Water insoluble, non-swelling, organic pigments are made by treating natural products of starch or albuminous character in aqueous suspension with solutions of free methylol compounds in which the methylol groups are directly attached to nitrogen atoms in the presence of small amounts of acid-reacting-agents and then heating the products at 110-150 DEG  C. for a short time.  The pigments may be coloured with dyestuffs which may be added during or after their manufacture.  Methylol compounds mentioned are dimethylol urea, tetramethylol acetylene diurea, methylol derivatives of carboxylic acid amides and urethanes.  Potato and rice starches and casein are natural products mentioned.  They may be used in tooth pastes, wound dusting powders, foot, face or body powders, in the paper, textile or leather trades and in the lacquer industry.  They may be admixed with other inorganic or organic pigments.  In examples: (2) a product obtained from casein and tetramethylol acetylene diurea is dyed with "Greifswalder Blau."ALSO:Medicinal compositions comprise water insoluble, non-swelling, organic pigments made by treating natural products of starch or albuminous character in aqueous suspension with solutions of free methylol compounds in which the methylol groups are directly attached to nitrogen atoms in the presence of small amounts of acid-reacting agents and then heating the products at 110-150 DEG C. for a short time.  The treated products may be impregnated with bactericides and are used as pigments for toothpastes, wound dusting powders, and foot, face and body powders.  Methylol compounds mentioned are dimethylol urea, tetramethylol acetylene diurea, methylol derivatives of carboxylic acid amides and urethanes.  Potato and rice starches and casein are natural products mentioned.  In Example 2 a product obtained from casein and tetramethylol acetylene diurea is impregnated with quaternary ammonium compounds to provide a disinfectant or dyed with a basic dyestuff such as "Greifswalder Blau" to provide a pigment for use in dermatology and veterinary medicine.