Bulk yarn is first blended with two different shrinkage fibers to form yarn, and then the yarn is treated in steam or hot air or boiling water. At this time, the fiber with high shrinkage produces greater shrinkage and is located in the center of the yarn And the low-shrinkage fibers mixed together, because of small shrinkage, are pressed on the surface of the yarn to form a loop, so that e68a84e799bee5baa6e997aee7ad9431333361323030 gets a fluffy, full, elastic and bulky yarn.China polyester FDY Yarns Suppliers

Performance

The bulk fabric woven by bulky yarn is generally finished by dyeing and raising (single or double-sided), etc. The fabric needs to be soft, fluffy, elastic and evenly dyed. Therefore, the bulkiness of bulked yarn, the specifications of raw materials, and the uniformity of mixing are its main performance indicators. The bulkiness is the degree of swelling of the original yarn after wet heat treatment. It is the main factor that determines the bulkiness, softness and elasticity of the fabric. Generally, the bulkiness of the yarn is required to be above 22%. In actual production, the shrinkage of the yarn is generally used as the measured index for checking the bulkiness, generally between 18% and 19.5%. The following issues should be noted about shrinkage measurement:

(1) Before measuring the length of the original yarn, pre-add 20g of tension; (2) Steam the measured raw material in steam for 5 minutes; (3) After shrinking the bulked yarn, add 20g of tension before measuring the length. If the bulkiness is too large, the grey fabric will be tight, fluffy and soft, and inelastic; if the bulkiness is too small, the grey fabric will be loose and the plush feel will be poor. The mixing uniformity of raw materials is an important reason for affecting the dyeing effect. Uneven mixing will cause uneven dyeing of the cloth and also affect the bulking performance.

Process flow
The characteristic of bulk yarn production is the mixed spinning of multiple raw materials. The main problem of spinning is how to achieve the full mixing of multiple raw materials. In addition, the wool fiber is generally more than 80mm and the longest is more than 150mm. How to adapt it to the technical performance of cotton spinning equipment is also an important issue. According to the traditional cotton spinning technology, there are two main ways to achieve the mixing of various raw materials: (1) Start mixing on the cotton table. The final mixing effect is better, but the blending ratio of the various raw material components of the final product is not very accurate; (2) Mix on the draw frame. Although this can keep the blending ratio accurate, it is not easy to mix evenly, and when some fibers are individually slivered, it is quite difficult to produce in the carding process due to the large static electricity. It can be seen that the traditional cotton spinning technology is difficult to meet the production technical requirements of bulk yarn.

In order to spin high-quality bulked yarn on cotton spinning equipment, a raw material pretreatment process is added before the cotton cleaning process. The purpose of this process is to shear wool balls into a certain length (51mm) of wool fibers, and mix a variety of raw materials here according to the design ratio, spray oil during the mixing process, and then mix the preliminary mixed The raw materials are packaged, and after the balance has regained moisture, they will go to the cotton station for formal production. Except for the raw material pretreatment process, all processes from bulking to winding are the same as the cotton spinning process, that is, raw material pretreatment process → opening and clearing process → carding process → Parallel process → Spinning process → Winding process → Packing.