Discussion on the spinning technology of the most

Discussion on the spinning technology of natural colored cotton knitted yarn

traditional cotton textiles can become colorful commodities only after being treated by dyeing and finishing processing technology. However, after dyeing and finishing processing, it will not only increase the processing cost of cotton textiles, but also destroy the excellent performance of cotton fibers, pollute the environment and destroy the ecological balance. Although researchers have done a lot of research on this, it has not been completely solved. Colored cotton textiles are made of natural colored cotton. As colored cotton is a pure natural raw material with color, it does not need dyeing from planting to product processing and will not form a source of pollution. It not only saves costs and reduces processing time, but also has good ecological and environmental protection performance. It is widely known as the "green and ecological" fiber of the 21st century. The fiber has the advantages of soft color, soft and elegant texture, elasticity and no fading. Therefore, the development and production of natural colored cotton products have high added value, market vitality and development prospects. Combined with the production practice of developing color cotton combed knitting yarn (14.5tex), the factors affecting yarn quality are tested and analyzed, and the measures to improve yarn quality are discussed

1 spinning process and main process parameters

1.1 raw material selection and performance characteristics

natural colored cotton fiber in addition to the above advantages, compared with natural colored white cotton, there are shortcomings such as short fiber main body length, low single fiber strength, maturity difference, poor uniformity, uneven color, poor fiber insolation, high short fiber content, more sterile seeds, high impurity content, more seed chips and leaves, and at the same time, the color difference between cotton bags is large, And there are mottled. Therefore, in the actual production, we should reasonably select according to the performance and color characteristics of natural colored cotton, so as to meet the requirements of knitted yarn, such as less neps, less hairiness, uniform evenness, fullness of color, etc. Table 1 lists the main physical indexes of three kinds of colored cotton

1.2 spinning process flow

Qinghua a002d-a006b-a036b-a036c-a092-a076-carding a186d-pre blending fa302-strip roll fa331-combed fa251-strip fa302 (two passes) a roving a454g-fa502 spinning winding no.7-type II Murata package

1.3 process parameters and measures of each main process

1.3.1 characteristics of the flower cleaning process

according to the characteristics of low strength of colored cotton fiber, the flower cleaning process adopts the process principle of "low speed, light weight, light strike, early falling and less crushing, more rows and less damage". A002d cotton grabber should grasp less and frequently to improve the operation rate of the cotton grabber; A036b adopts saw blade thugs, and a076 adopts comb needle blade thugs; The beating speed of each part is reduced by about 18%-19% to reduce the strike force and avoid excessive fiber damage and the increase of short fiber rate; The weight of cotton roll is controlled to be lighter, which is reduced from the original 420g/m to 38, meeting the technical requirements of the whole process of 5g/M; The self leveling device is adopted to ensure the vertical and horizontal uniformity of the cotton roll. The weight unevenness of the cotton roll is controlled at about 1.0% and the elongation is 1.5%. The main process parameters are shown in Table 2

1.3.2 carding process characteristics

colored cotton fiber has low strength and high lint content. The speed of the take-up roller and cylinder should be reduced appropriately to reduce the impact on the fiber, reduce the lint content, fiber damage and neps; The speed of cover plate should be properly increased to increase the total amount of cover plate flowers and improve the quality of cotton. At the same time, it can reduce short fiber filling cylinder needle root, improve carding degree and reduce yarn hairiness. The holding force of colored cotton fiber is poor, cotton is easy to fall and rotten edges, and the doffer speed should be appropriately reduced; All needle fabrics are made of Swiss Graf needle fabrics, which can improve the sharpness of needle fabrics, strengthen the carding of fibers, and improve the clarity of cotton; The spacing between cylinder and doffer is appropriately small, which is conducive to fiber transfer; The cylinder and cover plate are tightened. 5. The maximum axial pressing force of the driven plate is 20000n spacing, and the sliver is light weight. The carding process should be arranged according to the process principles of light weight, tight spacing and low speed. The main process parameters are shown in Table 3

1.3.3 drawing process characteristics

colored cotton fiber fineness difference is large, the length is short, and the short fiber content is high. It is necessary to appropriately reduce the roller spacing, reduce the roller speed, so as to prevent winding the roller and rubber roller, and improve the evenness of the sliver; The bell mouth with small caliber and heavy pressure are used to make the fibers close together, strengthen the control of fiber movement, and have a significant effect on preventing the exposure of fiber head end. On the other hand, it can improve the parallelism of fiber straightening and improve the evenness of sliver; Adopting the process route of large draft in the back area of head merging and small draft in the back area of second merging is conducive to fiber straightening. Therefore, the process principle of "tight spacing, heavy pressure, light weight and low speed" should be adopted in production. The main process parameters are shown in Table 4

experiments have proved that the finer the fiber fineness is, the greater the fineness difference is. Neps are easy to form when drawing frame is drawing at high speed, and the drawing speed is appropriately reduced, especially the second drawing speed plays an important role in yarn quality. The test results are shown in Table 5

1.3.4 process characteristics of combing process

color cotton fiber will discharge a large amount of lint and impurities through combing processing, and the straightness and parallelism of the fiber will be improved, which can improve the cohesion of the fiber, prevent fiber diffusion, reduce hairiness, and improve the yarn quality. After comprehensively considering the quality and cost, it is determined to choose 23% combed noil rate; Properly reducing the product of pre merging and drafting times of sliver can significantly improve the smoothness of sliver and the evenness of sliver

1.3.5 roving and spinning process characteristics

the color fiber has a large stretching force in the drafting process. The roving and spinning process should adopt the principle of "light weight, heavy pressure, appropriate twist coefficient, small jaw spacing, slow speed". The main process parameters are shown in Table 6

in order to improve the yarn quality of colored cotton, the main measures are as follows: 1) the winding density and twist coefficient of roving are appropriately larger, which is conducive to improving the internal structure of roving and improving the smoothness and evenness of roving. 2) Proper light roving weight can reduce the total drafting multiple of the spinning frame, help to reduce the shift deviation of the fiber in the drafting movement, and improve the evenness level; Appropriately reducing the roving winding diameter can reduce the unwinding tension and accidental elongation. The elongation should be controlled at about 1.0%, which is beneficial to improving the yarn evenness. 3) The moisture regain of roving is appropriately larger, which weakens the torsional and flexural stiffness of the fibers in the roving, so as to reduce the mutual exclusion of fibers and electrostatic interference. 4) Reduce the spindle speed and vehicle speed appropriately, use soft elastic not to deal with rubber rollers, and increase the pressure to maintain sufficient holding force to adapt to the stretching force, so as to ensure that the fiber moves smoothly in the drafting and improve the evenness level. 5) The spinning process should reasonably configure the process parameters of the spinning drafting and twisting winding parts, such as enlarging the roller spacing in the back area of the spinning, reducing the drafting multiple in the back area, adopting a smaller jaw spacing, appropriately improving the spinning twist, selecting a slightly heavier steel ring and a reasonable service cycle; Moving the front top roller forward by 1..5 mm, selecting matte steel rings and fluorine plated steel rings, using steel rings with a slightly smaller diameter, and maintaining good mechanical conditions, smooth spinning channels, stable and appropriate temperature and humidity in the spinning workshop are effective measures to improve the quality of colored cotton or yarn

1.3.6 technological characteristics of winding process

appropriately reduce the winding speed and tension, and adopt the groove cylinder with nickel cast iron metal Rockwell hardness test principle as shown in the figure to keep the winding channel unblocked; The temperature and humidity of the workshop should be properly controlled, which is beneficial to improve the electrostatic phenomenon and reduce the accumulation of flying lint to form new coarse knots and neps; The winding speed is adjusted from 1000m/min to 900 m/min, the winding tension scale is selected as 6 gears, the height of the balloon breaker is controlled between mm, and the adverse effects caused by tension elongation are reduced

2 semi product roving and yarn quality

2.1 semi product quality test results

semi product quality test results are shown in Table 7

2.2 yarn quality test results

yarn quality test results are shown in Table 8

3 conclusion

1. Compared with the properties of natural white cotton fiber, colored cotton fiber has shorter fiber length, higher lint content, more sterile seeds, poor main physical indicators and poor appearance quality, Reducing neps in sliver and improving carding effect of carding machine play a decisive role in improving yarn yield

2. The number of neps and hairiness of colored cotton yarn is more than that of natural white cotton, so the design and optimization of spinning process parameters need to be further studied and discussed

3. In addition to the reasonable design of process parameters, the spinning and winding process should maintain good mechanical conditions, smooth yarn channels, and appropriately improve the relative humidity and roving moisture regain in the spinning workshop, which will be conducive to improving the quality of colored cotton yarn