How to overcome the color difference in viscose filament dyeing？

The optimization and improvement of dyeing machine is one of the methods to improve printing and dyeing quality. In addition, the improvement and optimization of the process is also the key to improve the quality of printing and dyeing. Today, Huaxia technology introduces how to overcome the color difference of viscose filament dyeing.

Firstly, the physical and chemical properties of viscose filament should be understood; secondly, the following three points should be paid attention to when dyeing:

one

Strengthen the pretreatment, promote the fiber expansion, remove the additives attached to the fiber surface, so that the yarn can basically meet the dyeing requirements.

two

It is necessary to choose dyes with better migration and levelness.

The initial dyeing rate of viscose fiber is very high, but the dye uptake rate is not high. The defects such as color blooming and color difference in initial dyeing can not be made up even if the dyeing time is prolonged. In the selection of dyes, generally speaking, it is better to choose more water-soluble groups in the molecular structure of direct and reactive dyes.

The purpose is to reduce the initial dyeing rate and improve the levelness. At the same time, the hardness of water quality should not be too high. When dyeing, the chelating dispersant and better leveling agent can be added, and the dye can be added before the dye is added. After 10-15 minutes of operation, the dye can be added.

In addition, three primary colors with similar compatibility should be selected.

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three

Strictly control the process conditions, especially the heating rate, generally at 1 ℃ / min. In addition, both direct dyes and reactive dyes need electrolytes as dye promoters, and the latter needs alkali for fixation. Electrolyte and alkali should be diluted and added 3-4 times to ensure the dye uptake.

Generally speaking, the dye uptake is low at the beginning of dyeing and not necessarily low at the end of dyeing, which can be achieved by extending the dyeing time. The heat preservation dyeing time of rayon (yarn) is about 90 min, which depends on the dyeing depth. Because through through dyeing, we can get the correct shade and good color fastness.