Based on multiple feedbacks and complaints from customers, and after analysis, the author concluded that customers responded that there were too many neps and dead cotton. Most of them were not neps but dead cotton (white stars) with many immature fibers and no color. .
The percentage of immature fibers in cotton generally accounts for more than 50% of the short staple rate. More than 50% of the floating fibers in the spinning process are caused by immature fibers. A large number of neps and white stars are produced due to As a result of the changes in the movement trajectory of immature fibers in the fiber bundle, a large number of uneven dyeing and horizontal stripe defects will appear in cotton yarn dyeing and cotton cloth dyeing, resulting in a large number of defective yarns and fabrics, resulting in a large amount of waste. Therefore, analyzing changes in the percentage content of immature fibers is helpful for spinning mills to position cotton yarn quality. On the one hand, it can reduce production costs, and on the other hand, cotton of different qualities can be used rationally.
The influence of raw cotton on yarn quality
Based on the long-term experience of using American cotton in large quantities, the cotton yarn produced by machine-picked cotton has a large number of defects, especially the cotton yarn has many neps and short stubs, and these defects are difficult to remove during the spinning process. Sometimes even if the spinning process is increased, The production cost of yarn and the neps of cotton yarn have not been significantly improved. This has always been a very difficult problem for machine-picked cotton to spin high-quality, nep-less yarn. Production practice shows that the +200% neps of cotton yarn produced by machine-picked cotton are 10-40% more than the +200% neps produced by manual cotton picking. Most of these neps are used in the weaving process. Manifested in the form of cotton balls. In terms of the number of +140% neps, cotton yarn produced by machine-picked cotton is 10%-60% more than cotton yarn produced by manual picking. At the same time, the hairiness of cotton yarn produced by machine-picked cotton is also higher than that of manual cotton picking. Hairiness is 20-50% more.
Especially long hairiness is more obvious. High-quality dyed knitted fabrics are very afraid of such hairiness and neps. In other words, high-quality knitted fabrics require cotton yarns that are not machine-picked. yarn.
Due to the mixed phenomenon of cotton with good maturity and poor maturity in the fibers of this type of cotton yarn, the distribution of fibers with good maturity and poor maturity in the cotton yarn is uneven. For the dark and light colors of knitted fabrics, The use of fabrics is generally prohibited, otherwise knitted fabrics will easily produce horizontal stripes, hair particles, hair balls and white stars. This type of cotton yarn is best used on plain white cloth and bleached cloth of knitted fabrics, woven fabrics, because this type of cotton yarn has very few foreign fibers.
In recent years, due to the continuous updating of ginning technology, people have been pursuing the reduction of cotton impurities and the whiteness of cotton, and have upgraded the grade in order to improve economic benefits, thus resulting in cotton skin cleaning. According to production practice, information review, and peer exchanges, although the skin cleaning machine can remove some impurities and make the cotton brighter, it seriously damages the cotton fiber, increases the short staple rate, and also increases the number of small impurity particles. At the same time, it makes the spinning process of raw cotton more difficult. Not only are there many neps, but also the fine impurities are difficult to eliminate to the ideal state no matter how the process parameters are changed during the blowroom process, resulting in an increase in the number of fine impurities in the yarn and giving the fabric the style. Have a negative impact. At present, our country adopts machine-picked cotton in Xinjiang (the Sixth Agricultural Division that has been put into storage this time). Compared with artificially picked cotton, there are more impurities such as cotton leaves and cotton stalks but also a lot of foreign fibers. According to the current storage of machine-picked Xinjiang cotton Foreign fibers are at 0.8 g/ton. From the actual production point of view, it is best not to use these machine-picked cotton and transdermal cleaning cotton.
After machine-picked cotton is processed, there is a certain quality gap between the quality of cotton and the quality of manually picked cotton. This is mainly reflected in the shorter length of cotton, poor maturity consistency, poor uniformity, and short staple rate. High, high neps, many small defects, many fibrous seeds, and poor color consistency of cotton. During the spinning process of machine-picked cotton, due to the influence of the large number of small defects in the cotton, the large number of fiber-bearing seeds, and the defects mixed in the fiber, the blowing and carding process of the cotton is very important for the opening, impurity removal, short lint removal, and carding of the cotton. Subject to obvious limitations.
Machine-picked cotton has a very serious impact on the pre-spun semi-finished products during spinning. Due to the serious harm of small defects and fibrous seed debris in the spinning process, more will be dropped during the spinning process, and the cost will increase sharply. , this problem exists in many manufacturers currently. Moreover, the quality of carded slivers and combed slivers in the main pre-spinning process is worse than that of carded slivers and combed slivers produced by manually picked cotton, especially carded slivers and combed slivers produced by machine-picked cotton. Card slivers have more neps, fibrous seeds and short lint.
Due to the influence of climate and soil quality, early and mid-term fine staple cotton in southern Xinjiang generally has larger micronaire value, thicker fiber diameter, more foreign fibers, higher sugar content, lower fiber strength, and nep impurities. less. Compared with American cotton and other foreign cotton, its impurity content is lower, its short staple rate is relatively less, its length is longer, and its uniformity is moderate. Due to differences in varieties and geographical environments, yellowness and grayness have no comparative value, so southern Xinjiang fine-staple cotton (preferably hand-picked and without peeling) is suitable for knitting that requires lower spinning strength and fewer neps. yarn�
7. Since the United States and Australia are developed countries, all cotton is harvested by machines. Cotton is less polluted by human factors. The cotton yarn produced by this kind of cotton is particularly suitable for the production of bleached and bleached white cotton cloth.
8. The cotton from India and Pakistan is shorter in length, thicker in fineness, and has a higher content of various impurities and foreign fibers. It is generally only suitable for the production of cotton yarns below 20S. The quality of cotton in Central Asian countries is between China’s southern Xinjiang cotton and India and Pakistan cotton. Some cotton has better ginning quality, and some cotton has poor ginning quality, so the cotton yarn count produced by Central Asian cotton is average. At about 32 counts; cotton yarn is not suitable for the production of ultra-high-density knitted fabrics due to its relatively large number of impurities and defects. However, in some well-controlled areas, the number of impurities and defects in cotton production is small, and the consistency of cotton It is also better that this type of Central Asian cotton has a small amount, and the cotton yarn they produce is suitable for any fabric structure.
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