GB418835A - The production of multi-coloured artificial cellulosic materials in the form of bottle capsules - Google Patents

Abstract

Multicoloured bottle-capsules are obtained from viscose or other aqueous solutions of cellulose by separately dyeing or colouring any number of equal or unequal portions and bringing them together to form a heterogeneously coloured solution from which the capsules are formed, and regeneration or coagulation is effected before the differently coloured portions of the solution have completely mixed. If desired one or more coloured cellulose solutions may be mixed with an uncoloured solution. Alternatively, one or more colours or dyes may be heterogeneously added to a colourless or already uniformly coloured cellulosic solution. The dyes may be added in the form of solutions. Mixtures of different cellulosic solutions may be employed. Finely divided filling materials may be added to any of the differently coloured cellulosic solutions so as to obtain translucent or opaque effects. The capsules are obtained by dipping glass or other formers into the heterogeneously coloured cellulosic solution, and then dipping the coated formers into a coagulating or regenerating bath. The capsules while still on the formers may be dipped into baths for removal of any unregenerated cellulose, for bleaching, and other finishing operations. The capsules are stripped while in the wet state and are applied to bottle-necks to which they cling by shrinkage on drying. Dyestuffs which may be used are benzo-direct dyes, vat dye-stuffs such as indanthrene, acid dyes such as tartrazine and disulphine naphthalene, water-soluble anthraquinone dyes, chlorazol or thionol dyes, or pigment dyes. In some cases the colours may be discharged by the viscose, or by the precipitating, or coagulating baths, but the colours are restored by treatment with neutralizing baths or oxidizing baths.