GB490283A - Process for colouring cellulose esters or ethers - Google Patents

Abstract

Cellulose ester or ether threads, films, foils, ribbons, hairs, and other articles are coloured throughout their mass by introducing into the cellulosic material of which the articles are to be made, a coupling component and an organic substance capable of yielding a diazo compound of a fast base by a simple treatment with an acid, alkali, or steam, or even spontaneously, and then developing the colouring matter at any time before, during, or after the manufacture of the cellulose derivative articles. The colour - producing substances may be added to the cellulose derivative when the latter is in the dissolved, peptised, swollen, or solid state. Naphthols or naphthol derivatives may be used as coupling components. Diazo-amino compounds, stabilized diazonium salts, diazo-sulphonates, and anti-diazotates or nitrosamines, may be used as diazogene compounds. The coupling component and the diazogene compound may be dissolved in a solvent which is also a solvent for the cellulose derivative. The latter may be added to the solution, and the colour then developed. If the solution is too strongly coloured it may be mixed with an uncoloured solution. Pyridine, lower amines of the aliphatic series, or other solvents of basic character may be used. In an example, a mixture of the sodium salt of 3-diethyl - sulphamide - 5 - ethoxybenzene- 1 - azosarcosine and of the corresponding quantity of the p-chlor-o-toluidide of 2 : 3-oxynaphthoic acid is made into a paste with diethylene glycol and ammonia solution. The paste is diluted with acetone and added to a solution of cellulose acetate in acetone. The solution is kneaded until the colouring matter is produced. The solution may be cast, moulded, or spun to form shaped articles coloured a bright rose shade fast to light and soap. In another example, cellulose acetate soluble in acetone is impregnated with a swelling solution consisting of pyridine, ammonia, water, and a mixture of 4-benzoyl-amino-2,5-diethoxybenzene-1-azo (piperidine-3-sodium sulphonate), and o-toluidide of 2,3-hydroxy-anthracene carboxylic acid. The cellulose acetate is centrifuged, dried, and then treated with acetic acid, sulphuric acid, and sodium sulphate. It is washed, dried, and mixed with uncoloured cellulose acetate and dissolved in acetone. The solution is used for making threads, films, hairs, and other objects coloured a green-blue shade fast to boiling. In another example, cellulose acetate in pyridine is mixed with an alkali stable compound obtained by reacting the diazo derivative of 1-amino-4-benzoylamino-2,5-diethoxy-benzene with sodium sulphanilate in presence of sodium phthalate and adding o-naphthilide of 2,3-oxynaphthoic acid. The solution is precipitated in a solution of acetic acid. The product is mixed with uncoloured cellulose acetate and used for the production of threads, films, and other articles coloured a blue-violet shade.