Raw cotton bulk fiber dyeing technology
Color spinning products, sweaters, underwear, etc., the products produced by color spinning have great appeal in the consumption process. In the product development, we apply environmentally friendly dyes to dye the raw cotton, and we will spin the traditional process . Yarn--weaving--dyeing and finishing" was changed to the process of "dyeing cotton-spinning--weaving". This kind of dyed cotton has bright colors and better color fastness than natural colored cotton. At the same time, it reduces the discharge of dyeing sewage and reduces the environmental pressure. When spinning, the color cotton and white cotton are mixed according to different proportions, and then the key process of spinning is improved, which effectively shortens the production cycle and enriches the existing yarn varieties in the market. At the source of textiles, the raw materials are dyed and processed, and the technical improvement in the subsequent processes is conducive to the development of new products with high technology content, satisfying the consumer demand for color diversification and novel products.
1 Basic requirements for raw cotton dyeing The production process of raw cotton dyeing products: loose cotton (cotton)--into the pot--cleaning--staining--cleaning--soap-pretreatment--out-pot--dehydration-- Drying--packing dyed cotton
2, raw cotton bulk fiber dyeing
2.1 scouring
Raw cotton will be contaminated during planting, acquisition and processing. For example, during ginning, the crumb of cottonseed shell will stick to cotton. Although the raw cotton fiber is in a loose state, the dust and other impurities adsorbed on the surface also affect the dyeing effect. Therefore, the raw cotton should be washed and scoured before dyeing, which can effectively reduce the amount of colored cotton and improve the dyeing effect of the original cotton.
2.2 Raw cotton dyeing process
Raw cotton dyeing uses environmentally friendly dyes to increase the color yield and fixing rate, and to obtain good color fastness indicators, which can avoid the series of problems caused by “green barriers †when exporting . The principle of dyeing of raw cotton and dyeing of grey fabric is the same. Both the reactive dye and the hydroxyl group of the fiber react covalently to complete the processes of adsorption, dyeing and fixing. The difficulty in dyeing raw cotton is that when cotton is exposed to water and dyeing chemicals, it will swell. Under the microscope, the natural distortion of the fiber disappears. After dehydration and drying, there is a tendency to recover to the original state, but it cannot be completely restored to its original state. . At the same time, the effect of the cotton fiber on the external force during the processing is obvious, and it is easy to produce the wire and the dead knot, which affects the spinning process. The smallest unit of dyeing of the bobbin or the grey fabric is the yarn, and the fiber has been processed and solidified as required, so the state change during the dyeing and finishing process is much smaller than that of the original cotton dyeing. Cotton fibers contain impurities such as waxes, pectins, organic acids, proteins, non-cellulosic polysaccharides and ash, and - a proportion of lignified material. These waxes are very complex materials consisting of high molecular weight alcohols and fatty acids in free or esterified form. The distribution of natural waxes determines the water absorption. In the spinning process of raw cotton dyeing, we found that the wax contained in cotton is the main problem affecting the coloring of raw cotton, but it is beneficial to the spinning process. Although the absorption of dyes by cotton after scouring of strong alkali is increased, the loss of waxiness of cotton fibers becomes inelastic, the appearance is stiff, and the knots are damaged during the process of clearing and carding. Large, the short pile rate is sharply increased, and the spinning process cannot be carried out. We reserve the cotton dyeing process as the raw cotton wax, in the dyeing process, focusing on the use of additives, temperature control process, and minimize the force suffered the raw cotton, the raw cotton after dyeing increased - channel Pretreatment Thereby improving the elasticity and spinnability of the dyed cotton fiber.
2.3 Comparison of raw cotton dyeing costs with other dyeing methods
The traditional cotton post-treatment process has a long process route, consumes a lot of energy, and has serious pollution. The raw cotton dyeing imparts various colors to the cotton fiber, and the product is processed after being blended with white cotton into a yarn. After dyeing 1 ton of raw cotton, it can be mixed with white cotton to produce about 1-9 tons of yarn. After Jane yarn dyeing one ton of direct weaving, a single color. The various consumptions of ton yarn and ton cotton dyeing are basically the same, and the final product cost and result in subsequent production are greatly different. China is a country with scarce water resources. Compared with grey cloth dyeing, raw cotton dyeing can reduce dyeing wastewater by 90%, save 90% of water, and reduce the pressure of environmental and water resources protection. Mastering the relationship between yarn quality and raw cotton quality requirements is an important part of utilizing the characteristics of raw cotton, improving yarn quality, stabilizing production, and reducing costs. The increase in the rate of linters after dyeing of raw cotton is inevitable, just to control how much it increases. The raw cotton short pile rate is the main reason for the yarn breakage, which is unfavorable to the processing efficiency and product quality, but can be effectively solved after the reasonable blending with the white cotton and the adjustment of the spinning process.
3 raw cotton dyeing products development direction
(1) Purely dyed cotton or blended with white cotton can produce dyed cotton yarns with different purity, brightness and hue, all of which are suitable for environmental protection.
(2) The color fastness indexes of the raw cotton dyed yarns are good, and can be directly used for knitted underwear, baby products, T-shirts, towels, cotton socks, etc., and the finishing is simple.
(3) The color of bedding developed by dyed cotton yarn is soft, which meets the psychological needs of people in fast-paced cities. It is suitable for the market demand of bedding with many colors, varieties and small batches.
(4) The original cotton dyed yarn style is close to that of natural colored cotton. Adding ordinary color yarns which account for less than 10% of the total yarn ratio in natural colored cotton products not only destroys the inherent characteristics of natural colored cotton, but also greatly compensates for the shortcomings of rare color varieties, and is better than the dyeing effect of the yarn.
4 advantages of raw cotton dyeing in product innovation
(1) Raw cotton dyeing can diversify textile raw materials. It can avoid the staining of the other fibers after the dyeing process after blending, develop a variety of fiber blended and interwoven products, and improve the diversity of pure cotton products.
(2) The use of raw cotton dyeing to develop various fancy yarns with different purity, lightness and hue can promote the innovative development of yarn-dyed fabrics.
(3) Make full use of the clever design of fabric organization, popular color and various flower decoration lines , and promote the style of pure cotton products through CAD advanced means to meet the needs of individuality, fashion and leisure consumers.
(4) JC14 we developed . 6tex, JC18. The 2D dyed cotton yarn part of the yarn has a CV value of 25% of the Uster 2001 bulletin . It has laid a good foundation for the production of high-tech textiles and high-end clothing.
(5) Raw cotton dyeing improves the technical content of the product, and provides a barrier for the imitability of the product, which provides a new idea for product research and innovation .
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