The uncrimped chemical fiber has a smooth surface and poor cohesion between the fibers, which makes spinning difficult. The crimping of chemical fiber is entirely to meet the requirements of textile processing, improve the spinnability of the fiber and improve the wearability of the fabric. Whether the chemical fiber is crimped or not has a certain effect on the wrinkle resistance, bone and style of the fabric.

According to physical properties, chemical properties and appearance defects, the quality of chemical short fibers such as polyester staple fiber, nylon staple fiber, and polypropylene staple fiber can be evaluated. Generally divided into excellent, first, second, and third grade. The classification items and specific indicators of various chemical fibers are different, and they are stipulated in the inspection standards.

The physical and chemical properties of chemical short fibers such as polyester staple fiber, nylon staple fiber, and polypropylene staple fiber generally include breaking strength and its coefficient of variation, elongation at break, linear density deviation, length deviation, super long fiber rate, double-length fiber Content, curl number, oil content, etc. According to the characteristics of different varieties of chemical fibers, other indicators need to be tested.

For example, viscose fiber needs to be tested for wet breaking strength, residual sulfur content, whiteness and oily yellow fiber; synthetic fiber often needs to be tested for crimp rate, specific resistance, dry heat or boiling water shrinkage, etc.; polyester needs to be tested for 10% elongation strength ; Acrylic fiber needs to check the coloring rate, sodium sulfide content, hook strength, etc.; vinylon needs to check the moisture regain of the package, and the requirements are within the specified range.

The quality inspection of chemical short fibers is randomly sampled in batches. The same batch of fiber has the same raw materials, the same process conditions, and the same product specifications. The number of sampling is carried out according to the standard regulations according to the batch size.