| 摘要 |
Cotton, linen, jute, hemp, ramie, artificial silk, and other cellulose fibres are bleached with peroxides or other per-compounds at a pressure of at least 1.5 atmospheres above atmospheric pressure and at temperatures exceeding 80 DEG C. and preferably 100 DEG C. or more. The active agent may be hydrogen peroxide, sodium peroxide, or sodium perborate. The pressure may be produced hydraulically, by a pump, by pressure of a circulating bath, by expansion of the treatment liquid in a closed completely filled kier or by gas pressure. The alkali content of the bleaching bath is preferably low. Caustic soda, or sodium silicate may be used. The decomposition of the peroxide may be regulated by the addition of catalysts or of inhibitors. Iron apparatus may be used provided it is protected with a lime or magnesia cement coating. The process may be preceded by pressure boiling the materials with solutions of caustic soda, sodium carbonate, or lime. The materials may be treated with acid between the bucking and bleaching processes. The bleaching liquor may be applied cold to the materials so that on warming up in the closed kier pressure due to expansion is produced. The kier is opened to remove the enclosed air, then closed and the materials are boiled under pressure. The materials treated may be in loose form, or in the form of slivers, yarns, knitted or woven fabrics. In an example, cotton fabric is heated under pressure with caustic soda and sodium carbonate. It is washed and then heated at 110 DEG C. and under a pressure of 3 atmospheres above atmospheric with hydrogen peroxide and water-glass. In another example, slivers or knitted goods are heated under pressure with hydrogen peroxide, caustic soda, and water-glass. In another example, cotton goods are boiled under pressure with lime, washed, acidified, washed, and boiled under pressure with hydrogen peroxide and water-glass. |
