GB424398A - A process for manufacturing coloured cellulose-ester material - Google Patents

Abstract

Coloured cellulose ester material is produced by adding to a solution of a cellulose ester in an organic solvent, an ester salt of a leuco vat dyestuff, or an ester salt of another body yielding a coloured compound by acid oxidation previously dissolved in a solvent which is completely miscible with the cellulose ester solution, the mass being coagulated in known manner and the colour developed by acid oxidation during or after coagulation. The mass may be worked up into films, threads or the like, or it may be applied by printing to another material e.g. a textile fabric, and coagulated thereon. Suitable solvents for the ester salts are glycol, glycol monoethyl ether, glycol diethyl ether, diethylene-dioxide, and acetone. In an example, 1 gm. of the acid sulphuric acid ester-salt of leuco-dimethoxydibenzanthrone is dissolved in 20 c.c.s of glycol diethyl ether; this is filtered and mixed with 250 gms. of a solution containing 1 part acetylcellulose, 4 parts acetone, and 1 part of 95 per cent alcohol. The threads are rinsed and treated in a bath containing sodium nitrite, sulphuric acid and some ammonium vanadate, whereby acetyl cellulose threads of a fast green shade are obtained. In a further example, 1 gm. of the acid sulphuric ester salt of leucodibenzpyrenequinone is dissolved in 20 c.c.s of glycol diethyl ether, and added to 200 gms. of a solution of acetyl cellulose; similarly, a solution of ,5 gm. of the ester salt of leucotetrabromindigo, 10 c.c.s of acetone and 200 gms. of acetyl cellulose solution is prepared; the two mixtures are applied to a cotton fabric in any desired design and the solvent evaporated; on treating in a bath containing sodium nitrite, sulphuric acid and some ammonium vanadate, at 50 DEG C., yellow and blue relief effects are produced. Further examples describe the production of films dyed pink and a fast green. Specification 403,049 is referred to.