| 摘要 |
1,050,712. Bleaching cellulosic fibres. OFFICE NATIONAL INDUSTRIEL DE L'AZOTE, Aug. 4, 1964 [July 30, 1963; June 19, 1964], No. 31158/64. Heading D1P. Unbleached natural cellulosic fibres, e.g. linen and cotton fabrics, are bleached by contacting them with an aqueous solution of pH not below 6.5 of trichlorocyanuric acid, dichlorocyanuric acid or one of its salts, or a mixture of the said acids or salts or both. If the fibres have not been desized they may be given a pre-treatment with an aqueous solution of pH below 6.5 of trichlorocyanuric acid, dichlorocyanuric acid or one of its salts, or a mixture of the said acids or salts or both, the pH there being raised to at least 6.5 by the addition of an alkali, e.g. an alkaline carbonate, bicarbonate or hydroside. If the bleaching is effected at a pH adjusted to 10 or above by the addition of an alkaline carbonate or hydroside undesized fibres may be both bleached and desized. Cyanuric acid may also be added to the bleaching bath. Bleaching may be effected at ambient temperature or at 95-100‹C. |
