Spandex is the textile fiber with the best elastic elongation and elastic recovery rate by now

Spandex is the textile fiber with the best elastic elongation and elastic recovery rate by now, which has been favored by people since its emergence. However, with the development of the textile industry, various drawbacks of spandex fabrics have also been amplified, such as the relatively large deficiencies in color fastness, anti-aging and other aspects. In order to effectively solve these drawbacks of spandex and further meet the market requirements, people put their eyes on the polyester elastic fiber.

PBT and PTT both belonged to polyester series have begun attracting attention from people, and their structure is similar to that of PET, but the alkane chain of the dihydric alcohol is longer. After the carbon chain of the dihydric alcohol increased, the flexibility of the molecular chain of the polyester is enhanced, and the structural characteristics of the "segment" of the hard segment and the soft segment in the molecular chain are more and more apparent; therefore, the elasticity of the polymer or fiber is enhanced, but the elasticity of these stretch fiber is lower than that of spandex, and the main products are polytrimethylene terephthalate (PTT) fibers and polybutylene terephthalate (PBT) fibers. Although these two kinds of fibers can be directly woven, able to meet the requirements of general textiles, due to the disadvantages of being easily deformed by heat, easy to burn, low mechanical strength, and unstable fabric shape, people turn attention to the development of two-component composite elastic fibers.

The two-component composite elastic fiber is a crimped elastic fiber made of two kinds of polymers having different structures and properties, and formed into a two-component composite yarn by conjugate spinning in a certain ratio. Its elasticity is not based on the movement of hard and soft components in the molecular chain, but the difference in shrinkage or elongation of the two components in the fiber. After heat treatment, the fiber forms a spiral or wavy curl under internal stress. The crimped fibers have varying degrees of flexibility and elasticity, and their elasticity differs depending on the chemical composition, molecular structure, distribution in the fibers, and the ratio of the two components.