Shallow Discussion on the New Dyeing and Finishing Technology of Silk Knitted Fabrics

1 EKL-2 special foam agent characteristics and application

The raw silk used in the silk knitting factory is made of crepe and automatic reeling. The reeling factory's raw silk, especially the 44/48dtex automatic reeling yarn, has a large bending rigidity, and it is very difficult to make loops, resulting in the failure of knitting. Therefore, it is necessary to increase the flexibility and lubricity of the yarn by the foaming. The traditionally used foaming agents in silk knitting companies are representative of additives L and additives WS, but they are poor in softness and lack smoothness, even if some of them are soaked or alkali-pretreated and then soaked. Due to the complex process, the softness and smoothness of raw silk cannot meet the technical requirements of knitting production. As a result, the silk weft knitted fabrics are unevenly distributed, the fabrics are rough, and a large amount of the sericin powder is flaked, so that the needle grooves are blocked, and the tongue needles cannot be flexibly moved, resulting in sickles such as dilute road needles. And the white powder deposits on the fuselage, which affects the service life of the machine, and even the expensive imported needles cause broken needles due to repeated friction. The main reason is that the raw silk thread is not completely soaked. Some silk-knitting manufacturers had to apply a layer of white oil or sulphate with low sulfonation directly on the yarn during weaving. However, it caused a large amount of oil traces and filaments on the fabric blank so that the quality of the sliver was not improved. Good, the oil marks are hard to train, the oil in the scouring tanks gathers, and the stains are again contaminated. There are more than 10 types of foaming agents available in the country, including oil additives and wax-free (integrated) additives, among which the silk knitting special foaming agent EKL-2 has the best performance and the best results. EKL-2 foaming agent is mainly composed of a variety of surfactants and refined mineral oil, with a solid content of (25 ± 2)%, PH value of 6 ~ 7.5. The foaming agent has a simple application process and is easy to operate. The soaking process conditions of 60kg/piece 44/48dtex raw silk are shown in Table 1.

Table 1 44/48dtex raw silk soaking process

The soaking process of EKL-2 foaming agent is simple and does not need to be degummed in advance. Even if it is a kind of automatic twinning silk 44/48dtex, it can have very good softness and smoothness after soaking treatment according to Table 1 process. The coefficient of dynamic and static friction is significantly reduced, and its strength and cohesion performance are superior to those of other filaments soaked in silk. Not only can it be used smoothly for knitting, but also it can make the filaments resistant to friction and the white powder can be significantly reduced, thus protecting the machine and prolonging the life of the knitting needles. The surface of the fabric is also smooth and smooth, the coil is even, the scouring performance of the silk fabric is good, the whiteness is good, and the hand feels plump and smooth, and the quality is significantly improved.

2 The scouring of silk knits

The traditional scouring process of silk knitted fabrics is old and not optimized. Due to the long time, the saponification method is not easy to control because of the scouring process. It is not suitable for hard water, and the surface of the silk is easy to cause gray injury, crease marks, soap marks, etc., and it is easy to yellow. It is rarely used now. The enzymatic scouring process is complicated, the production efficiency is low, the cost is high, and there are not many manufacturers. In recent years, China successfully developed a new series of high-performance scouring agent EAT series, which is one of the representative varieties of a new generation of silk scouring agent in China. High-performance scouring agents EAT-2 and EAT-31 protect silk fibroin at high temperatures above 95°C, thereby avoiding gray injuries. For regions and manufacturers with poor water treatment conditions, river water, lake water, or tap water can be used directly. The scouring agents EAT-2 and EAT-31 not only have the silk fibroprotecting function, but also have a strong metal ion blocking function, can chelate and adsorb Ca2+, Fe3+ ions, so as to avoid rust spots on the silk; and can chelate calcium. , magnesium ions, reduce the hardness of water, no soap spots. When EAT is used as an efficient scouring agent, it is not necessary to add a mercerizing soap, dispersant WA, Remiphon A, additives 209 and 808, etc., and it is not necessary to add chelating agents such as EDTA. [Practice has proved that: EAT series silk high-performance scouring agent has three major characteristics of protecting silk fibroin, blocking metal ions and high efficiency and rapidity, and is worthy of being applied and promoted by silk knitted garment enterprises.

Staining of silk knit fabrics

When the silk knit fabric is dyed dark with a rope machine or an overflow machine, there are many gray injuries and more creases. Especially when heavy fabrics are dyed black or dark blue, defects such as color flowers, gray wounds and creases are often exposed. Some experts in the industry have proposed that the revolution in silk dyeing technology should be preceded by the addition of Pingping and O. Because Pingping plus O has a good affinity for anionic dyes, it is easy to combine with dyes into stable larger aggregates in low temperature areas, so it is difficult to dye at low temperatures. At high temperatures, the aggregates rapidly decompose, and the dye molecules released are rapidly dyed. For dyes with high dyeing speed, dyeing, coloring, stains, etc. occur. Especially when heavy silk is darkly stained, this is a common technical problem in the company. The development and application of high-performance, high-quality ESV-01, ESV-02 special effects leveling agents and processes to replace the decades-old flat-padded and O-old process are the key measures to solve the above problems and improve the dyeing quality of silk knitted fabrics.

In the rope machine or overflow dyeing machine, special process leveling agent ESV- 02 dyeing heavy silk knitted silk typical process formulae are shown in Table 2.