Patent GB-190615160-A (GB)
Title: A Process for the Preparation of Discharging Resists under Vat Dye-stuffs upon Colours capable of Discharge by Means of Hydrosulphites.
Inventor: RIBBERT PAUL
Filed: 1906-07-03
Granted: 1907-01-31
Abstract: 15,160. Ribbert, P. July 3. Dyeing.-Relates to the production of discharge resists consisting of sulphoxylates or their derivatives together with substances which will not decompose the sulphoxylates in the cold and will act as resists for the over-printing colour. With alkali-sulphoxylates, metallic salts may be used, such as lead sulphate, sulphite, or acetate, zinc acetate or sulphate, or aluminium or chromium acetate. With acid-proof sulphoxylate derivatives, such as the amino- or arylamino - derivatives, ammonium salts, chloride, sulphate, oxalate, or nitrate may be used, with or without organic acid, such as acetic, lactic, or tartaric acid, or acidreacting salts such as aluminium sulphate or sodium bisulphate. With salts of heavy or alkaline-earth metals of aldehyde sulphoxylates, such as the basic zinc salt of formaldehyde-sulphoxylic acid, suitable solvents, such as ammonium salts, are used with or without organic acids, aluminium sulphate, sodium bisulphate, or sulphur. The metallic sulphoxylates are preferably prepared in the colour itself from the sodium salts. Coloured discharge resists may be obtained by addition of chromates when lead salts are used, or when other metallic salts are used by the addition of such dyestuffs as are resistable and proof against hydrosulphite and can be fixed by a short steaming, for example, mordant dyes such as chromo-glaucin, or dyes which can be fixed as leuco-bodies in the presence of neutral or acid agents, such as phenocyanine, modern-blue, modern-violet, or modernyellow. The discharge resists are printed upon colours obtained with dyes which can be discharged by hydrosulphites, for example, p-nitraniline-red; after drying these colours are printed upon with a vat dye-stuff such as indanthrene, flavananthrene, or indigo or thio-indigo red, or a sulphur dye such as immedial-blue or immedial-yellow ; the fabric is then dried, steamed, and washed, treated with chromium salts if necessary (or passed through acid if zinc sulphoxylate has been used), and finally soaped. The following examples are given :-(1) A white discharge resist is prepared by heating a mixture of British gum, China clay or burnt starch, water, gum solution, and hydrosulphite N F h÷chst, adding zinc sulphide, or lithopone, or both, and then zinc acetate or sulphate and aluminium acetate. (2) A discharge resist with lead salts is prepared by heating British gum, China clay or burnt starch, water, gum solution, hydrosulphite N F h÷chst. and adding lead sulphate and acetate. (3) Discharge resists from acid-proof sulphoxylate derivatives are obtained (a) by dissolving with ammonium chloride in a thickening- agent the condensation product of o-toluidine with sodium formaldehyde-sulphoxylate; (b) the reaction product of ammonia, hydrosulphite, and formaldehyde is dissolved with ammonium sulphate in a thickening-agent, and aluminium sulphate is added. (4) Rongalite C is dissolved in British gum and heated with zinc acetate and sulphate until the zinc sulphoxylate is precipitated, ammonium chloride is added, and the mixture is heated till the zinc salt dissolves. (5) For indigo, zinc sulphoxylate and ammonium chloride are dissolved in gum solution, and sulphur and acetic or lactic acid are then added. (6) A blue discharge resist is made by heating together British gum, burnt starch, water, gum solution, hydrosulphite N F h÷chst, and adding lead acetate, sulphate and sulphite, and a mixture of chromo-glaucin B M I (h÷chst) with British gum,water, gum solution, and chromium acetate. The following are given as examples of over-printing colours :-(1) Indanthrene S B is mixed with caustic soda and a thickening of dextrin, burnt starch, water, chalk, kaolin, rongalite C, and caustic soda. (2) Flavanthene-paste B A S F is mixed with rongalite B and a thickening of dextrin, kaolin, water, and caustic soda.