Patent GB-415822-A (GB)
Title: An improved process for delustring natural and artificial silks
IPC: D06M11/48
Filed: 1933-03-11
Abstract: Fibres of natural or artificial silk, which may be dyed or undyed, weighted or unweighted, are delustred by treatment in either order with an aqueous solution of a tungstate or molybdate and with an aqueous solution of a salt of an alkaline earth metal. The process is applicable to yarns or woven fabrics and to the production of delustred designs by printing.  Reducing agents, e.g. hydrosulphites, sulphites, bisulphites, or organic derivatives thereof, may be incorporated, e.g. with the tungstate or molybdate, to ensure the production of white, instead of yellowish, delustring effects.  The following examples are specified.  (1) Viscose yarn is delustred by subjecting it to a brief immersion in a lukewarm aqueous solution of sodium tungstate or ammonium molybdate, drying, treating with an aqueous solution of barium chloride, washing and drying.  (2) A satin made of viscose and cotton is delustred by padding with sodium tungstate solution, drying and treating with barium chloride solution; mixtures of other artificial fibres, e.g. of the acetate, nitro or cuprammonia type, with cotton or other fibres may be similarly delustred.  (3) A viscose-cotton mixed material is printed with an aqueous paste containing sodium tungstate and tragacanth with or without a suitable dyestuff, dried and treated with barium chloride solution; the printed areas are delustred.  (4) Viscose rayon piece goods are printed with a paste containing barium chloride, dried at 40--50 DEG  C., treated with sodium tungstate solution, washed and dried to obtain delustred effects.  (5) Viscose rayon piece goods, dyed with a dischargeable dyestuff such as Trisulphone brown B, are printed with a paste containing sodium tungstate and hydrosulphite, with or without a suitable dyestuff such as Rhodamine 6G, dried, steamed, treated with barium chloride solution and washed to obtain white or coloured delustred effects. (6) Viscose satin, padded with an aqueous aniline black solution containing aniline salt, aniline, potassium ferricyanide, sodium chlorate and sodium formaldehyde sulphoxylate, is dried, printed with an aqueous paste containing sodium tungstate, tragacanth and Hydrosulphite RFN, steamed for 2 minutes, treated with barium chloride solution, washed, developed in a sodium silicate bath, washed and dried to obtain white delustred effects on a black lustrous ground.  (7) Viscose cr<\>zepe is printed with two aqueous pastes, one containing sodium tungstate, sodium sulphite and tragacanth and the other containing Chloramine sky blue FF, Tetracarnit (Registered Trade Mark), glycerol, dextrin and sodium phosphate, and the printed material is dried, steamed for 1 hour, treated with barium chloride solution, washed and dried to obtain white delustred effects and a blue design.  (8) A satin made of natural silk and cotton is delustred by padding with sodium tungstate solution, drying and treating with barium chloride solution.  (9) A natural silk-cotton mixed material is printed with an aqueous paste containing sodium tungstate and tragacanth, dried and treated with barium chloride solution to obtain delustred effects. Specifications 305,828 and 318,467, [both in Class 2 (ii)], are referred to.  The Specification as open to inspection under Sect. 91 comprises also a further example according to which a piece of acetate artificial silk tissue is printed with an aqueous paste containing barium sulphocyanide and tragacanth, dried, passed through sodium tungstate solution, washed and dried to obtain a delustred design; it comprises also delustring by the interaction on the materials of any water-soluble salts of acids of metals of the sixth group of the periodic system with any water-soluble salts of polyvalent metals and includes additional examples of (a) the interaction on a viscose cr<\>zepe or an acetate artificial silk of sodium tungstate in a padding solution with copper sulphate, uranyl chloride, stannous chloride, cobalt sulphate, ferrous sulphate, chrome alum or manganous chloride to obtain delustred material of various colours, (b) the interaction on rayon piece goods of copper acetate, cobalt sulphate or a mixture of stannous chloride and sodium stannate in a printing paste with sodium tungstate, (c) the interaction on a piece of cr<\>zepe-de-chine of a sodium tungstate padding solution with copper sulphate; the sodium tungstate may also in Example (6) above be replaced by sodium chromate or bichromate or by ammonium uranate. This subject-matter does not appear in the Specification as accepted.