GB552189A - Improvements in and relating to the production of colouring matters - Google Patents

Abstract

552,189. Dyes and dyeing. BRITISH BOOT, SHOE & ALLIED TRADES RESEARCH ASSOCIATION, and RUSS, A. COLIN-. June 20, 1941, No. 7815. [Classes 2 (iii) and 15 (ii)] Azo dyes. Colouring matters are obtained by coupling a diazotized aromatic amine with a degradation product of a protein or albuminoid material, especially leather, such product being obtained for example, by breaking down the protein biochemically or by the action of an acid or alkali, in some cases after a treatment with nitrous acid. The protein degradation product may be used in admixture with customary coupling components. Examples are given of the production of coupling solutions by (1) heating scrap bottom leather with caustic soda solution, (2) heating scrap chrome upper leather with caustic soda or hydrochloric acid solution. In examples of the production of the colouring matters, (3), (4) and (5), diazotized 4 - amino - N - dimethyl - aniline is coupled with (3), the alkaline solution obtained in (1), (4), the acid solution obtained in (2) after concentrating it and making alkaline with caustic soda, (5) a similar solution derived from chrome leather pre-treated with nitrous acid, (6) tetrazotized dianisidine, (7) tetrazotized 3:3<SP>1</SP>-dichlorobenzidine, (8) tetrazotized tolidine, (9) tetrazotized benzidine is coupled with the alkaline solution of (1) after modifying the alkalinity by addition of acetic acid. Aniline, 4 - nitroaniline, 1:8 - naphthylaminesulphonic acid, 2:4:8 - naphthylaminedisulphonic acid and 1-aminoanthraquinone are also specified as diazo components. Azo dyes forming on the material. The dyes may be produced upon fabrics by padding with a solution of the protein degradation products and treating with a solution of a diazo salt. Specification 425,689 is referred to.