How to choose suitable cot apron according to types of slub yarn?
Slub yarn is a new type of fancy yarn popular in recent years. Its quality directly affects the weaving efficiency and fabric style of the later process. Cots and aprons are the main equipment of spinning drafting, which play an important role in yarn quality, especially when the level of raw materials and equipment changes little. For the spinning of slub yarn, the function of cots and aprons can not be ignored. Although there are large and small slubs on slub yarn, the reflection of yarn slightly uneven is not obvious, but the yarn line dry difference will affect the definition of slub on cloth, and the three-dimensional concave convex effect and level sense of slub yarn are not obvious, thus affecting the style of cloth. Moreover, the other quality requirements of slub yarn are not lower than that of ordinary yarn. Because of the existence of a large number of slubs, the single yarn breaking strength decreases, the strength CV value increases, the hairiness increases, and even the "big belly slub" with the slub coarseness much larger than the standard slub coarseness appears. Therefore, the breaking rate is relatively high in the spinning and weaving process, and even affects the fabric appearance.
If the cots and aprons can be used reasonably when spinning slub yarn, it can not only improve the sliver dry and strength of slub yarn, reduce the CV value of the strength, reduce the hairiness, reduce the broken ends, reduce the appearance of "big belly slub", but also reduce the cost and improve the efficiency.
How to choose cot apron reasonably?
There are many kinds of slub yarn fiber, and the common spinning varieties include pure cotton slub yarn, hemp cotton slub yarn, polyester cotton slub yarn, pure polyester slub yarn, polyester viscose slub yarn, etc. Different types of fiber require different cots and aprons.
Pure cotton slub yarn
Cotton slub yarn is generally used to weave denim or medium and high-grade clothing fabrics. We use the double-layer cots of shore A65 and shore A70 to spin c14.6 tex slub yarn respectively. We have done a lot of comparative tests on the same spindle. The test data show that the yarn spun with shore A65 cots has high breaking strength, small strength CV value and less hairiness. Therefore, the glue with low hardness and good elasticity should be selected for spinning pure cotton slub yarn, especially pure cotton fine and special slub yarn Roll. The lower the hardness of the cot, the better the elasticity. Under the pressure, the width of the gripping jaw composed of the cot and the roller shortens the length of the floating area and the length of the twisting triangle area, which is beneficial to the sliver drying and hairiness reduction. Moreover, the horizontal gripping is even, and the edge fiber of the whisker has strong control ability, which is conducive to the reduction of fiber loss, so as to improve the yarn strength and reduce the strength CV value. If we choose aluminum liner cots, the quality will be better, but we need surface micro treatment to reduce the wound and broken ends. In addition, we have also made comparative tests on the diameter of cots, the hardness of aprons, and the inner patterned aprons and the flat aprons. The test results show that the yarn quality has been improved to some extent by using the large diameter cots, the low hardness aprons and the inner patterned aprons, but the degree of improvement is smaller. Generally speaking, when spinning pure cotton slub yarn, the cot diameter is 29 mm-30 mm, the shore a hardness is 60-70 degrees, and the top apron shore a hardness is 60-65 degrees.
Ramie cotton blended slub yarn
Hemp cotton blended slub yarn is generally used to make clothing fabrics or bed textiles. We spin hemp cotton 58.3 tex slub yarn. Because the length of hemp fiber is very poor, the length is more than 100 mm, and the length is only 10 mm. It is not easy to draft with normal draft, and it is easy to get out of hard head, so we use slippery draft, but there are many broken ends. Through analysis, most of the broken ends are "little mice" with short fibers gathered, that is, the short fibers are not effectively controlled in the drafting process System. We have reduced the front and back roller spacing and the back draft multiple to the minimum, and the jaw spacing is also too small to grasp. We have made comparative tests on the spinning frame with different diameter cots of shore A68 degree and shore A75 degree respectively, and measured the broken ends when the spindle is 1000. From the data, we can see that the hardness of COTS is low, and the broken ends are few; the diameter of COTS is large, and the broken ends are few. Because of the use of large diameter, low hardness cots spinning, the short fiber has been better controlled, at the same time, the width of the grip jaw line has been increased, the length of the floating area has been reduced, the longer hemp fiber can be stretched out through the slide draft, and the roving will not be lowered; the shorter hemp fiber can also be effectively controlled, so the yarn breakage is greatly reduced. Generally, the diameter of COTS is 29.5mm-30.0mm, the hardness of Shore A is 68-70 degrees, and the hardness of Shore A is 65 degrees.
Polyester cotton blended slub yarn
Polyester cotton blended slub yarn is generally used for weaving medium and high-grade clothing fabrics with high quality requirements. However, polyester fiber has a large tractive force in the process of drawing, so it is not easy to draw out the "big belly slub", so the pressure should be increased to enhance the grip. If the hardness of cots and aprons is too small, they are easy to deform under high pressure, and are easily damaged by polyester fiber's greater traction, which is more serious for polyester cotton slub yarn with large number. By testing the CV value and hairiness of yarn strength for many times, and checking the damage degree of cot surface, we conclude that: when spinning polyester cotton blended slub yarn, the hardness of cot Shore A is generally about 70 degrees, the diameter is 29.5mm-30.0mm, and the hardness of upper apron Shore A is 65 degrees. The CV value of yarn strength is relatively small, the hairiness is relatively small, the "big belly slub" is less, and the yarn quality is obtained The utility model can ensure that the requirements of the users are met and the service life of the cot is prolonged. The hardness of COTS should be increased when the yarn number is large.
Spinning pure polyester and polyester viscose slub yarn
Pure polyester, polyester viscose slub yarn, medium and fine tex yarn are generally used to weave medium and high-grade clothing fabrics, and coarse tex yarn is generally used to weave decorative fabrics such as curtains. Medium and fine tex yarn should not only reduce strength CV value, reduce hairiness, ensure yarn quality, but also extend the service life of cots. Through testing the yarn strength CV value and hairiness for many times, and checking the damage degree of the cot surface, we conclude that: Generally speaking, the cot with shore a hardness of 70-75 degree, diameter of 29.5mm-30.0mm and upper apron of shore A65 degree is suitable for spinning medium and fine polyester slub yarn or polyester viscose blended slub yarn, and it is required to have good antistatic and winding resistance. The quality requirements of coarse and special yarn are not very high, and the main problem is "big belly slub". The main solution is to enlarge the spacing and increase the pressure. Therefore, the cots and aprons with high hardness and good antistatic performance should be selected, and the cot diameter should be larger. Based on the statistics and comparison of the number of yarn defects removed by the electronic yarn cleaner in the winding process (i.e. "big belly slub" which is 50% coarser than the slub coarser) and the inspection of the damage degree of the cots, we have concluded that: for spinning the slub yarn of coarse polyester or the slub yarn of polyester viscose blend, the hardness of the cots is generally shore a88-92, the diameter is 29.5mm-30.0mm, and the hardness of the upper apron is shore A70 It is suitable to be at 75 degrees.
The practice shows that the selection of cots and aprons according to the fiber types and characteristics of slub yarn can not only improve the yarn strength, reduce the strength CV value, reduce the hairiness, reduce the broken ends, improve the smoothness and fullness of slub yarn, ensure the yarn quality, prolong the service life of cots and reduce the cost.
