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How to use direct black to dye interweave velvet of mulberry silk and viscose silk?

Mulberry silk and viscose silk interwoven velvet mainly includes 65111 Georgi velvet and 65302 golden velvet. The former is a plain woven pile fabric with mulberry silk as ground warp and weft and viscose silk as pile warp; The latter is an interwoven velvet fabric with mulberry silk as ground warp and weft viscose silk as velvet. Therefore, it can be seen that their warp / weft components are basically the same, so the scouring and dyeing methods are also similar. Direct dyes are selected for dyeing, because direct dyes can dye both cellulose fibers and protein fibers. We choose direct black D-RSN, D-HR, D-ANBA, VSF600, GGF and direct fast black GF (all are environmental protection dyes). For cellulose, direct dyes are mainly based on van der Waals force and hydrogen bond binding force; For protein fiber, it is mainly salt binding. Therefore, the color fastness of direct dyes on protein fibers is better than that of cellulose fibers to a certain extent. In addition, the direct dye is cheap and easy to use, and the color fastness can meet the requirements after being treated with cationic fixing agent. Therefore, the dye is widely used in velvet fabrics. In order to make these two kinds of velvet fabrics black by direct black dyeing, the method of light scouring and heavy dyeing can be adopted. The specific operation methods are as follows:

First of all, the amount of soda ash (Na2CO3) in fabric scouring can be reduced to 1 ~ 2 g / L. of course, the degumming effect of mulberry silk will be worse, but there is no need to worry about it. Because no matter what kind of direct black is used, it is necessary to dye black on cellulose fiber or protein fiber. When dyeing, in addition to Canadian bright powder (na2s04) as dye promoter, 1.5% – 2% soda ash (Na2CO3) needs to be added. At this time, the sericin remaining on Mulberry silk can be removed in the dyeing process, which does not affect the hand feeling and style of the finished product.

Secondly, since the dosage of dye is 10% – 15% (OWF), in order to prevent defects such as color flower and color stain (spot) in dyeing, in addition to adding leveling agent, it is better to add 1.5 ~ 2 g / L dispersant. It can not only prevent dye condensation from producing dyeing defects, but also improve the silk chirp and the overall dyeing effect.

Sometimes, in order to dye according to the standard sample, some corresponding acid, neutral, or even alkaline dyes are often added to adjust the color light. Due to the existence of dispersant in the dyeing bath, many problems can be avoided. The practice shows that in order to achieve the same color of the two fibers, it is required to dye at 95-98 for more than 60 minutes, sometimes even reduce the dyeing temperature to 85-90 , and then prolong the dyeing time, so as to achieve the purpose of transparent dyeing and make the color of the two fiber components uniform and plump.

Velvet fabrics shall be processed in the whole process on the star frame dyeing machine and shall not be stacked to avoid folding and flanging. After dyeing, fully wash with water, and then treat with 5% (OWF) cationic fixing agent at 45 ~ 50 ‘for 30 minutes. Add L ~ 2 ml / L (98%) acetic acid in the fixing bath to overcome the polymerization inhibition of the fixing agent itself and neutralize the residual alkali agent on the mulberry silk, so as to ensure the neutral drying of the fabric and avoid brittleness.

Post time: Apr-21-2022