When other conditions are the same, the longer the fiber length, the higher the yarn strength; under the premise of ensuring the yarn strength, the longer the cotton fiber length, the finer the limit fineness of the spun yarn; The shorter the length of the cotton fiber, the thicker the ultimate fineness of the spun yarn; the effect of the length uniformity of the recycled polyester staple fiber on the spun yarn strength cannot be ignored. When the short staple ratio of the original yarn is higher than 15%, the yarn strength will decrease significantly.
The longer the fiber length and the higher the length uniformity, the better the yarnlevelness; when the fiber length is very short, especially when the length uniformity is poor, a large number of short fibers become floating fibers during the drafting process, resulting in the deterioration of the yarnlevelness and the decrease in yarn quality; if the requirements for the yarn strength are the same, when spinning with a longer fiber, a lower twist coefficient can be selected, the fiber ends in the spun yarn are less exposed, the surface of the yarn is smooth, and the hairiness is also less.
From the structure and size of the cotton spinning machine to the process parameters of each process, it must be closely matched with the length of the raw materials used. For example: when the length of cotton fibers is different, the form of the cotton cleaning machine should be changed.
The change of twist coefficient, when spinning with polyester staple fiber, the twist coefficient of spun yarn is larger, while when spinning with long fiber, the twist coefficient is smaller; in addition, due to the poor length uniformity of cotton fiber, in order to improve the strength of spun yarn, to improve the yarnlevelness, it must also go through the carding process. Excluding a large amount of short staples and controlling different combing noil rates can control the length uniformity of the fibers.
(1) When other conditions remain unchanged, the finer the fiber, the higher the yarn strength. In order to ensure the strength of the yarn, the fine fibers in the recycled polyester staple fibers can be used with finer yarns.
(2) The fineness of polyester staple fibers has a significant effect on the evenness of the yarn. The finer the fibers, the lower the evenness of the yarn.
(3) The finer the polyester staple fiber, the worse the rigidity, and the fine fiber should not be used as the pile yarn of the pile fabric.
(4) The finer the polyester staple fiber, the easier it is to kink or break during processing. When the cotton cleaning and carding are not handled properly, a large number of short fibers are likely to be generated, and a large number of neps are easily formed when the drawing frame is drawn at high speed.