Method for improving dye-uptake of direct dyes on cotton fabrics

Abstract

The invention relates to the field of textile printing and dyeing, and discloses a method for improving the dye-uptake of direct dyes on cotton fabrics. The method comprises the following steps that (1) the cotton fabrics are treated by a chitosan solution, specifically, the pretreated cotton fabrics are completely immersed in the chitosan solution, then an excess solution is rolled out, pre-roasting is conducted, heating and solidifying are conducted, then washing is conducted in a weakly acidic solution, and then drying is conducted; and (2) dyeing is conducted, specifically, the treated cotton fabrics obtained in step (1) are placed in a direction dye solution for stirring, then heating and heat preservation are conducted, and the cotton fabrics are soaped and dried; wherein in the step(1), the preparation method of the chitosan solution comprises the steps that chitosan is dissolved in a citric acid solution with the concentration of 40-50 g/L; and the concentration of the chitosan solution is 10-15 g/L. According to the method, citric acid is used as a crosslinking agent, the chitosan is crosslinked on the cotton fabrics, and the dye-uptake of the direct dyes on the cotton fabrics is improved.

Description

technical field [0001] The invention relates to the field of textile printing and dyeing, in particular to a method for improving the dyeing rate of direct dyes on cotton fabrics. Background technique [0002] Due to the poor affinity of direct dyes to cellulose, it is difficult to obtain a high dye uptake rate in the dyeing of cotton fabrics, resulting in a low apparent color depth (K / S) of the dyed fabrics, which is difficult to obtain. Dye dark. [0003] Cationic modified cotton fabrics are a solution that can alleviate this problem. This technology uses cationic modifiers on the surface of cotton fibers, such as 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC), and dyes the grafted cotton fabrics at a specific pH. The amine group in the neutralizing agent is protonated to be positively charged under acidic conditions, and forms an electrostatic attraction with the negatively charged sulfonate and carboxylate groups in the direct dye, thereby improving the de...

AI Technical Summary

Problems solved by technology

[0004] Although this technology can greatly increase the dyeing rate of direct dyes, it poses a health threat to operators due to the extremely strong pungent odor and strong toxicity of common cationic modifiers

At the same time, if the wastewater produced by this process is not strictly treated, it is very likely to cause serious pollution to the external water environment after discharge.

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