Patent GB-346544-A (GB)
Title: Improvements relating to the decorative treatment of textile fabrics
IPC: D06P5/15
Filed: 1930-03-13
Abstract: Azo dyes, forming on the material; printing.-Reversible patterns in varied colours are produced on fabrics by applying, in the several treatments of the process of the parent Specification, colour mixtures and materials which develop or fix one or more of the colours in the mixture and destroy or prevent the fixation of another or others of the colours.  In one application, the fabric is padded with an azo component, and after drying one side is printed with a thickened mixture of a diazo compound and vat dye, which penetrates through the fabric.  One side of the fabric is then printed with a mixture which will destroy the azo colour and fix the vat dye.  In an example of this process, the fabric is impregnated with Naphthol AS, printed through with a mixture of Caledon jade green and Fast Scarlet R salt in one roller and Indanthrene brilliant violet 4R and Fast orange R salt in another roller, and then printed or padded on one side only with a thickened paste containing Formosul, potassium carbonate, glycerine and anthraquinone.  The resulting pattern appears in green and violet on one side of the fabric and in red and orange on the other side.  The Naphthol AS may, if desired, be applied to one side only of the fabric, the discharge paste being applied to the opposite side.  In order to limit the degree of penetration of the fabric by the discharge paste, the colour mixtures may contain Resist salt L and may be thickened with carob-bean gum, or the fabric may be back-filled with starch before applying the paste. In another application, the fabric is printed through with Indigosol O, Alizanthrene Yellow G and sodium nitrite in one roller and Indigosol violet A.Z.B, Ciba Brown G and sodium nitrite in another roller, and one side is then padded or printed with a paste containing Formosul, potassium carbonate and glycerine, which fixes the vat colours and resists the Indigosols.  The latter are developed on the opposite side of the fabric by passing through sulphuric acid. In a further modification, opposite sides of the fabric are padded or printed with different colour mixtures, and the mixture of ingredients which destroys or prevents the fixation of the azo colours and develops the vat colours is printed through the fabric. In an example of this modification, the fabric is prepared with Naphthol AS, printed through with a paste containing Formosul, potassium carbonate and glycerine, and printed or padded on opposite sides with pastes containing Alizanthrene yellow G and Fast violet B salt and Caledon jade green and Fast scarlet R salt respectively.  In another example, the unprepared fabric is printed through with Naphthol AS in one roller, Naphthol A.S.G. in a second, and Formosul, potassium carbonate and glycerine in a third roller, and opposite sides of the fabric are then printed or padded with mixtures containing Variamine blue B salt and Caledon jade green, and Fast scarlet R salt and Caledon blue G.C.P. respectively.  In a further example, the fabric is prepared with Naphthol AS, printed through in a three-colour pattern with Fast violet B salt in one roller, Caledon jade green, Formosul, potassium carbonate and glycerine in a second, and Formosul, potassium carbonate and glycerine in a third roller; opposite sides are then printed or padded with mixtures containing Fast scarlet R salt and Indanthrene brilliant violet 4R and Alizanthrene yellow G, Indigosol green AB and sodium nitrite.