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配方说明: |
Cotton Boil-Off Bleaching and Dyeing |
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Cotton contains as much as 2000 ppm. of metal salts, these being mostly salts of calcium magnesium, iron, and aluminum. When cotton is given a kier boil-off or a continuous boil-off, this metal contaminant is reduced to about 200 ppm. It is generally assumed that kier boiling or continuous boil-off and bleaching operations purify cotton completely. This is, however, not the case, so that if fully softened (5 to 15 ppm. hardness) water is used, there is still 200 to 600 ppm. hardness present in the cotton. A kier-boiling operation consists of boiling cotton cloth under pressure in an iron machine. Kiers normally are filled with 6000 lb. of cotton cloth tightly packed by running the cloth continuously in the kier and having a man tramp it with his feet to pack it tightly. The kier is subsequently filled with a solution consisting of 0.5% sodium hydroxide, 0.1% of some surface-active agent, varying from rosin soap on the low side to good synthetic detergents on the high side, and in many innstances con |
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