| 摘要 |
Cellulose fibres, e.g. textile fibres, yarns and fabrics, paper, cotton wool, wood pulp and straw are bleached by subjecting them to the action of an aqueous hypochlorite in the presence of a bromide. The bromide may be present at the beginning of the operation or may be added after an initial bleaching with hypochlorite alone, and may be produced in the vat by the addition to the latter of elementary bromine. In examples: (1) cotton cloth is bleached in sodium hypochlorite containing potassium bromide and after the initial bleaching more hypochlorite is added; (2) and (3) cotton cloth is bleached with hypochlorite, potassium bromide being added at an intermediate stage; (4) and (5) the first example is repeated using caustic soda and bromine water or a sodium hypobromite-bromide solution instead of potassium bromide; (6) cotton cloth is bleached in a vat p containing aqueous sodium hydroxide into which chlorine and bromide have been introduced; (7) cotton cloth is bleached in a vat prepared by introducing chlorine and bromine into an aqueous suspension of calcium hydroxide. |
