Synthetic fibers with high elongation at break (above 400%), low modulus and high elastic recovery. Chinese trade name for multi-block polyurethane fibers. Also called elastic fiber. Spandex has high elongation (500% to 700%), low elastic modulus and high elastic recovery rate. Except for higher strength, other physical and mechanical properties are very similar to natural latex silk. It is more resistant to chemical degradation than latex silk, has moderate thermal stability, and has a softening temperature above 200°C. Most dyes and finishes for synthetic and natural fibers, also suitable for dyeing and finishing of spandex. Spandex is resistant to perspiration, seawater and various dry cleaners and most sunscreens. Long-term exposure to sunlight or chlorine bleach can also fade, but the degree of fading varies widely depending on the type of spandex.

The reason why spandex fiber has such high elasticity is because its polymer chain is composed of low melting point, amorphous "soft" segment as parent and high melting point, crystalline "hard" segment embedded in it. The flexible segment molecular chain forms a certain network structure with a certain cross-linking. Due to the small interaction force between the molecular chains, it can be freely stretched, resulting in a large elongation performance. The rigid segment has a relatively large molecular chain binding force, and the molecular chain will not extend unrestrictedly, resulting in high resilience. The cross-section of radon filaments is mostly dogbone-shaped, and some filaments have smooth or serrated surfaces. The breaking strength is the lowest among all textile fibers, only 0.44~0.88CN/dtex (the strength of polyether type is higher than that of polyester type).

The moisture absorption range is small, generally 0.3-1.2% (the moisture absorption rate of multifilament is slightly higher than that of monofilament). The heat resistance varies greatly depending on the variety. Most fibers are stored in the range of 90 to 150 °C for a short time, and the fibers will not be damaged. The safe ironing temperature is below 150 °C, which can be heated for interference and wet cleaning. It has excellent dyeing performance and can be dyed into various colors. The dye has a strong affinity for fibers, and can be adapted to most types of dyes. It has good chemical resistance, and is resistant to most acids and alkalis, chemicals, organic solvents, Dry cleaning agents and bleaching agents, as well as sun and wind and snow resistance, but not oxidation-resistant, easy to yellow fibers and reduce strength.

88%POLYESTER12%SPANDEX JERSEY 11SP035-P