| 摘要 |
Protein fibres are treated with a sulphur-containing reducing agent in a proportion from 1 to 40 per cent by weight of the material treated and at a pH from 2 to 7 and a temperature from 0 DEG to 100 DEG C., and also with an optical bleaching agent before, during or after the treatment with the reducing agent. The reducing agent may be sodium bisulphite, sodium hydrosulphite, sulphur dioxide or sodium formaldehyde sulphoxylate, and may be converted into a colourless, sparingly soluble salt under such conditions that the salt is precipitated on the fibres and adheres thereto, e.g. sodium bisulphite may be converted into the calcium salt by treatment with calcium chloride. The optical bleaching agent may be an amino stilbene, 4 - methyl - 7 - dimethyl - amino - coumarin, 4 - methyl - 7 - ethyl - amino-coumarin or b - methylumbelliferone. In examples, wool is bleached with hydrogen peroxide and is then treated with a solution containing formic acid, diamino - stilbene - disulphonic acid and (1) sodium bisulphite, (2) sodium hydrosulphite or (3) sodium formaldehyde sulphoxylate. In Example (4) the wool, after bleaching with hydrogen peroxide, is treated with a solution containing sodium bisulphite, calcium chloride, b - methylumbelliferone and ammonia. |
