GB343102A - Improvements in or relating to the printing of cotton - Google Patents

Abstract

Dye preparations; printing.-Dyestuff pastes for cotton-printing purposes are made by reducing vat dyes in the presence of water, a water-soluble alcohol, and an alkali weaker than an alkali metal hydroxide, such as potassium carbonate or ammonia. Glycerine, glycol, diethyleneglycol, glycerine oxyethylether, thiodiglycol, and thiodiglycerol are specified as water soluble alcohols; mixtures of such alcohols and commercial products such as crude glycerine lyes containing them can also be employed. The preparations may be mixed with hydrotropic agents before or after reduction, such agents including urea, substituted ureas, thiourea, hexamethylenetetramine, potassium ethylether sulphonate, potassium or sodium isovalerate, and alkali salts of the following acids:-isobutyric acid, phenylacetic acid, benzoic acid, o-toluic acid, salicylic acid, benzene sulphonic and sulphinic acids, p-toluene sulphonic and sulphinic acids, naphthalene sulphonic acids, e.g. a - and b -naphthalene sulphonic acids, aniline sulphonic acids and their substitution products e.g. dimethylsulphanilic acid, dimethylmetanilic acid, diethylmetanilic acid and dimethyl-2-toluidine-4-sulphonic acid, and hydroaromatic carboxylic and sulphonic acids, e.g. cyclohexanecarboxylic acid and tetrahydronaphthalene-b -sulphonic acid. Sodium hydrosulphite is preferably employed as reducing agent; iron-carbonyl and titanium trichloride are also specified. In examples, (1) the dyestuff obtained by coupling 1 : 2-pheno-5-oxynaphthocarbazole with isatin anilide is reduced with hydrosulphite in the presence of ammonia and glycerine, the preparation thus obtained is pasted with a thickening containing wheat starch, British gum, tragacanth, glycerine, potassium carbonate and sodium formaldehyde sulphoxylate, printed in the usual manner, and the prints are steamed and developed with potassium dichromate and acetic acid, (2) the dyestuff of Example 1 of Specification 201,786, [Class 2 (iii), Dyes, &c.], is reduced with hydrosulphite and ammonia in the presence of crude saponification glycerine and urea and printed as in Example 1, (3) the dyestuff of Example 1 of Specification 2592/07, [Class 2, Acids and salts, Organic, &c.], is reduced with ammonia and hydrosulphite in the presence of glycerine and sodium benzenesulphonate, (4) the dyestuff of Example 2 of U.S.A. Patent 1,537,928 is similarly reduced in the presence of glycerine or diethyleneglycol and urea, (5) the dyestuff from 6-methoxy-3-oxythionaphthene and 4-methyl-6-brom-2 : 3-dihydro-3-ketothionaphthene-2-(p-dimethylamino)-anil (Specification 222,094), [Class 2 (iii), Dyes, &c.] is reduced with hydrosulphite and ammonia in the presence of glycerine and sodiumbenzene sulphonite, (6) 6 : 61-diethoxythioindigo is similarly reduced, (7) 6 : 61-dichlor-4 : 41-dimethylthioindigo is reduced with hydrosulphite and ammonia in the presence of phthalic anhydride, which reacts with the ammonia to form ammonium phthalate; instead of phthalic anhydride, the sodium salts of p-dimethylamino-benzoic acid, o-cresotinic acid, or dimethylsulphanilic acid may be used, (8) 4 : 7 : 41 : 71-tetramethyl-6 : 61-dichlorthioindigo and 6 : 61-dimethyl - 4 : 41 - dichlorthioindigo are similarly reduced, the sodium salts of benzenesulphonic acid, dimethylmetanilic acid, dimethylsulphanilic acid or salicylic acid being used instead of phthalic anhydride, and (9) Caledon jade green is reduced with ammonia and hydrosulphite in the presence of crude saponification glycerine and sodium dimethylmetanilate or sodium naphthalene-b -sulphonate. Glycerine derivatives.-Glycerine oxyethylether, which is not a uniform compound, is made by treating glycerine with ethyleneoxide. Thiodiglycerol is made from monochlorhydrin and sodium sulphide.