How to overcome the twist of viscose filament yarn of printing and dyeing color

1. The dyeing of viscose filaments is prone to chromatic aberration. The reasons are as follows:

①The form of multiple pages in the vertical slits of the fiber surface, so the hygroscopicity, in the whole wet treatment (pre-treatment and dyeing), the yarn shape variation, the increase in weight, directly affect the wet treatment effect;

②Viscose fiber, viscose filament, amorphous and crystalline regions are irregular, and raw materials, during the spinning process, especially in common areas;

③Especially silk and viscose silk, the pretreatment of printing and dyeing machinery has not gained wide adaptability. Facts have proved that the spray dyeing machine is more preferable;

④The strengths of ordinary silk and viscose filaments, they are because they have certain limitations in the application of shiny silk, which is beneficial to improve spinning and fiber performance, spinning matting agent, adding (titanium dioxide) and Smooth, soft, anti-mildew, anti-foam, anti-static, anti-oxidant surfactants, from matt and semi-matt silk and silk, because of the difference in the degree of light refraction and gloss of silk, it overcomes the color The spot color yarn, viscose filament itself, first of all, have a certain understanding of physical and chemical properties.

2. Please pay attention to the following three points in dyeing:

1) Strengthen the pre-treatment to promote fiber swelling and completely remove the additives on the fiber surface to meet the basic dyeing requirements and propose the following recommended process:

Prescription (g/L)

Sodium hydroxide () 2-5

Sodium carbonate 2-4

Scouring agent HS-120A (closed in Wuxi) 3-5

Na2S2O4

Process conditions (spray dyeing machine)

Bath ratio 1:10-15

Keep temperature (℃) 95-98

Holding time (min) 60-90

Thorough removal. Sodium hydroxide is easy to clean, so after washing, also use 98% acetic acid solution 2ml/L, (room temperature), the fiber remains neutral until the dye proves that it is better, and the strength of the fiber is minimal. Scouring agent HS-120A is an anionic/complex and non-ionic, anionic emulsion with excellent washing effect, dyeing and other performances. The non-ionic part is pretreated for a long period of time at a higher temperature, but in every There is a big difference between batch viscose filaments, so before formal production, through small scale.

2) The dye transfer and dye leveling we have to choose are better. The initial infection rate of viscose fiber is very high, and the absorption rate is not high, the dye-colored flowers, colors and other defects, even if the dyeing time is prolonged, the dye can not be selected in general, direct and reactive dyes should choose water-soluble group (- SO2Na) molecular structure, more is better. The solubility of the dye should be large, and it should be directly low. The purpose is to reduce the incidence of initial infection and improve the leveling property, while the hardness of the water should not be too high. In addition, chelating dispersants and better leveling agents are added for dyeing. Run for 10-15 minutes. In addition to the dye, the compatibility of the dye should be close to the three primary colors.

3) Strictly control the process conditions, especially the heating rate usually at 1°C/min, is appropriate. In addition, whether it is direct dyes or reactive dyes, there are supplementary electrolytes (sodium sulfate or sodium chloride) as accelerators, which also fix the color by adding alkali. The electrolyte and alkali are diluted and increased by 3-4 times to ensure the absorption rate of the dye. Under normal circumstances, the lower initial dye dyeing, the dyeing rate is not necessarily low at the end, you can extend the dyeing time. The dyeing time of insulating viscose silk (yarn) is about 90 minutes. Depending on the depth of dyeing, it may be because the dye is only passed through to obtain the correct shade and good color fastness.