Discussion on key technology of wool/cashmere/silk worsted fabric

1 multi-component fiber fabric design ideas

Although natural fiber has good performance, it has some defects, such as poor shape retention, machine washability, poor washability, easy wrinkling, pilling, easy to produce aurora, difficult to maintain, low strength, etc. Its application is limited. At present, the most realistic and easiest way to achieve this is to rationally mix several kinds of fibers, develop multi-component fabrics, and design and produce high-quality, new-style textiles by complementing the advantages and disadvantages of different fibers. Based on this design idea, we have developed a series of wool/goat silk blended fabrics. The finished products are elegant and soft, with smooth and full-bodied, elastic foot, light and warm, moisture-absorbing and breathable, good drape, comfortable to wear, reflecting noble and elegant. Exquisite style, physical indicators also meet the national standards and achieve the design goals.

2Development of wool/goat silk worsted fabric plush yarn

In wool, cashmere and silk, wool has good elasticity and warmth, but it is easy to shrink; silk is soft and smooth, elegant in gloss, good in moisture absorption, unique in performance for winter and summer wear, but poor in light resistance, easy to wrinkle in wet state; cashmere It has the characteristics of fineness, lightness, softness and slipperiness. Its hygroscopicity is in the forefront of all fibers. Its products are noble and elegant, but the fibers are easily damaged and expensive. Based on the above-mentioned natural fiber performance analysis, the reasonable ratio of natural fiber, screening suitable process parameters, and exploring the blending technology of wool, silk and cashmere are proposed to achieve the purpose of complementary performance, so that the products are smooth and silky. The effect has the fullness of the cashmere wool slippery, elastic foot feel, light weight and warmth, moisture absorption and breathability, noble and elegant, low cost. To this end, we have developed a multi-component fabric that uses wool as the main body and adds appropriate amount of cashmere and silk.

The key technologies of plush silk worsted fabrics are discussed below.

2.1 Raw material selection

The key to raw material selection is fiber length. The length of silk fiber is generally above 85mm, while the length of self-comb cashmere fiber is generally about 42mm. The difference in length between the two is large, which increases the difficulty of spinning and is not conducive to the uniformity of yarn drying. . The wool fiber of 75~80m//1 length is selected as the main body, which takes into account the performance of silk and cashmere, which is beneficial to improve the quality of yarn. The specific qualities of wool, cashmere and silk are shown in Table 1.

The design idea is to express softness, fullness and elasticity, and appropriately increase silk to improve gloss and smoothness. Warp yarn density 11tex X 2, weft yarn density 20tex X 1; wool 80%, cashmere 10%, silk 10%. Based on the principle of length consideration, the combination ratio of the three raw materials can be appropriately changed to obtain different styles of products.

2.2 Process line and spinning process points

The process flow and technical parameters mainly consider these three kinds of fiber lengths, and the gauges increase the pile velvet; the small gauge will damage the silk and wool. We use the special process of silk, wool, kun, combing, and then mixing, which can solve the problem of unevenness caused by the difference in length, and also help to solve the problem caused by the affinity of similar fibers. Uneven yarn, affecting the problem of dyeing the same color. The main process points are as follows:

(1) The needle comb spacing is 46-42 mm, and the drafting multiple is 6-8.

(2) After the wool thread is refueled, it should be allowed to stand for 2 to 8 hours to make the oil and water penetrate evenly, eliminate the stress and static electricity generated in the previous production, and recover the fiber damaged by accident.

(3) The needle comb is lightly fed and lightly stripped to reduce combing of the hair. The processing process of the sliver is: (1) wool + mulberry silk mixed strip (two times) - two needles - combing;

(2) Wool/mulberry silk combing strip three needles and one end needle.

2 . 3 dyeing

A method in which one-step strip dyeing or cheese dyeing is performed in the same bath after mixing first. In the one-step dyeing of the same bath, the visual homochromatic effect is the key. Although wool, cashmere and silk are all protein fibers, their chemical structure, physical properties and morphological characteristics are different. The proportion of amino acids contained in them is different. For example, polar amino acids and sulfur-containing amino acids in wool and cashmere are higher than Silk; silk is much thinner than wool cashmere, the surface area is much larger, the number of dyes required to dye the same depth will inevitably increase; the crystallinity of silk is higher than that of wool cashmere; the isoelectric points of the three fibers are different. All of these factors make the dyeing temperature, dyeing speed and dyeing rate of wool, cashmere and silk different, so it is difficult to achieve the same color effect. After research and exploration in production practice, it is found that the following aspects must be paid attention to in order to achieve the visual color effect.

(1) Dye selection. There are many dyes to choose from. Considering the dyeing conditions for the coloring, color fastness and damage to silk and cashmere of silk, wool and cashmere, some neutral dyes and hair reactive dyes such as Lanna Mountain and Lanna are used. Free and easy. Practice has proved that the color fastness and gloss of the wool dyed with reactive dyes are better, and the color fastness can generally reach 4.5 or above. However, dyeing dark color also requires post-treatment and alkali fixation.

(2) Dyeing temperature. Because the surface structure of wool, cashmere and silk is different. Below 90 ° C, wool and cashmere surface due to the tight structure of cystine-containing scale layer, coupled with higher oil content, will hinder dye dyeing during the dyeing process, so the wool and cashmere color is very low . The silk structure is loose, the color can be colored at low temperature, and the coloring rate is high. After dyeing, the silk color is deep, while the wool and cashmere are lighter in color; after 90°C, the scale layer of wool and cashmere is fully opened, and the dyeing rate is high. Greatly increased, because the coloring group of wool and cashmere is 40% higher than silk. Therefore, in the end, it exceeds the silk, causing the dye dyed onto the silk to be desorbed and transferred to the wool and cashmere, showing that the color of the wool and cashmere is deepened, and the silk is lighter. Therefore, the dyeing temperature is controlled at about 90%, and it is easy to achieve the same color effect. In addition, the blending ratio of fibers should also be considered. When the silk content is less than 30%, the color fastness of wool and cashmere should be considered, and the temperature is 90%; if the silk content exceeds 30%, the temperature should be lower than 90 °C. . It is best to be around 85 °C.

(3) pH value. The lower the pH value, the higher the dyeing rate of protein fiber, and the higher the exhaustion rate. The dyeing rate of wool and cashmere is higher than that of silk. Therefore, when the pH value is lowered, the color ratio of wool and cashmere is higher than that of silk, showing wool. Cashmere is dark in color and silk is light, and the same color is not good. And the pH value is too low, the color is too fast, it is easy to cause uneven dyeing and damage the fiber, so the pH should be controlled at 5-6.

(4) Yuanming powder dosage. When the pH value is 2~3, the isoelectric point of the silk appears. When the pH value is 4.2-4.8, the isoelectric point of the wool appears. The pH values ​​of the isoelectric points of the two natural fibers are quite different. Yuanming powder can make the silk puff, so it plays a role in promoting the dyeing of the silk, and it has a slowing effect on the wool and cashmere. The higher the amount of Yuanming powder, the greater the amount of silk coloring. Therefore, the proportion of silk is large, and the amount of Yuanming powder should be increased], which is conducive to achieving the same color effect. However, the amount of Yuanming powder should not be too much, otherwise there will be uneven dyeing. When dyeing dark colors, the general dosage is 30g/L.

(5) Holding time. As the holding time is extended, the dye on the silk is transferred, which makes the silk color lighter, while the wool and cashmere color becomes darker, which is not conducive to the same color effect. Generally, the holding time is controlled at about 50 minutes.

(6) Dyeing bath ratio. When the bath ratio is large, the concentration of the dye liquor is small, and the dye dyeing fiber is slow, thereby increasing the dyeing probability of the dye on the silk, and is advantageous for achieving the same color effect.

(7) Lanna Mountain dye dyeing temperature rise curve is shown in Figure 1.

2.4 finishing

Process: green inspection, singeing, falling water, pre-cooking and washing, one water absorption, one dyeing tank, one water absorption, one double boiling, one water absorption, one drying, one inspection, one ripe repair, one brush, one steaming, one finished product

Process parameters: increase pre-cooking shape, 85 ° C, 6 times, 4 pressure, off-machine cooling. Other parameters are the same as ordinary wool and cashmere fabrics.

3 Conclusion

(1) Different styles of raw materials can be selected to obtain different styles of wool/cashmere/silk blended products.

(2) When dyeing, relatively hydrophobic additives should be used to promote swelling to improve homochromaticity.

(3) The key process is to optimize the selection of raw materials and establish the process route

And parameters, screening dyes and determining the dyeing process. For example, heating rate, maximum temperature, holding time, dye bath pH value control, Yuanming powder dosage, etc., the heating rate must be slow, the above operation process and parameter selection directly affect the visual color effect and color fastness of the product, and must be strictly managed. Standard operation.

(4) Increase the pre-cooking shape during finishing to prevent wrinkles, control the shrinkage rate, strengthen the soft shape, and highlight the luster, lubrication and softness of the fabric.

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