GB451115A - Improvements in the process of bleaching textile fibres, yarns and fabrics - Google Patents

Abstract

Textile fibres, yarns, and fabrics are bleached by means of a non-alkaline bleaching bath containing hydrogen peroxide stabilized by an organic acid, phosphoric acid, or boric acid, with the goods travelling continuously through the bath, or the liquor maintained in continuous flow into and out of the bleaching vessel, or with the goods and the liquor flowing in countercurrent through the vessel. Suitable organic stabilizing acids are oxalic acid and lactic acid. The presence of sulphuric, hydrochloric and nitric acids is excluded. The goods may contain activators such as soap or alkali, and the bath may contain protective agents such as glue, gelatine, or formaldehyde. In an example, wool containing small amounts of soap and fat is passed through a bath containing 0,5 per cent of hydrogen peroxide and 0,01 per cent of oxalic acid which is circulated and constantly kept up to strength. The wool is then passed through hot rollers. In another example wool goods are packed into a container through which is circulated a solution of hydrogen peroxide stabilized with mono-sodium phosphate. The solution is kept up to strength by adding hydrogen peroxide and phosphoric acid. The goods are then treated with ammonia, drained, and dried. Specifications 277,628, [Class 1 (ii)], 347,292, and 404,019 are referred to. The Specification as open to inspection under Sect. 91 refers to the treatment of sensitive organic materials, particularly fibres, in aqueous stable solutions of oxygen-yielding bleaching agents like hydrogen peroxide or compounds having the -OOH- group, while moving the material and/or the liquor. Stabilizing agents specified are colloids, alkali salts of organic sulphonic acids, or esters of sulphuric acid. The materials may contain activators such as enzymes, ferments, metal salts and oxides (other than those of the iron group), or compounds capable of increasing the pH value. The process may be combined with washing, oiling, greasing, impregnating, preserving, or dyeing the material in the same or different baths, and agents specified for these purposes include sodium dodecanolsulphate, triethanolamine, sodium octadecoylmethylaminoethane sulphonate, sodium dodecanolpersulphate, sodium 3, 5, 3<1>, 5<1>, tetrachloro-2, 2<1>-dioxytriphenylmethane-2<11>-sulphonate (deterrent for insects), acid fluorides, hydrofluoric acid, fluoboroacetic acid, fluoboro-oxalic acid, fluosulphonic acid. Preservatives specified are sugar, tannins, aluminium salts, gelatine, glues, resinates, salts of aromatic polynuclear sulphonic acids, and solium formaldehydesulphoxylate. Other examples are given. This subject-matter does not appear in the Specification as accepted.