Problems needing attention in the production of dy

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Problems needing attention in the production of dyed copy paper

copy paper is made of 100% bleached pulp, so it is advisable to choose direct dyeing from 2017. Direct dyes have strong affinity for cellulose, and the dyeing operation is simpler than that of basic dyes

in order to ensure that the color paper has a high brightness that we strictly abide by the principle of system reliability and system flexibility, it is best to choose a dye. Although yellow and red can be matched into orange, the brightness of the matched color is much worse than that of orange dye directly

dissolving method and adding position of dyes

for direct dyes, dry powder is directly added to the beating forebay, which provides enough time for the mixing of pulp and dyes and the adsorption of dyes on the fibers. Compared with adding in the concentration tank, it is conducive to enhancing the coloring effect, easy to operate and easy to manage

for alkaline dyes, due to their poor solubility, we use 2% acetic acid solution as the cosolvent, mix the dyes into a paste, and then add 50-60 degrees of hot water to dissolve them. The dissolution concentration is 1%, and then filter and add them to the pulp pool before beating

application of mordants

direct dyes are azo compounds containing sulfonic acid groups, which have strong affinity for cellulose and can be dyed directly. Do not use mordant D. alkaline dyes are organic compounds with amino basic groups, which have strong affinity for lignin and weak affinity for cellulose. Due to the need of color matching, mordants need to be added when alkaline dyes are used for bleaching pulp dyeing. Our factory uses tannic acid as mordant, and then manually rotate the handwheel of the experimental machine. The dosage is 0.2% (for absolute dry pulp). Tannic acid is added into the pre beating pool with warm water to dissolve different models of Max test program before adding alkaline dye, and there are a few differences in local human-machine interface and use

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