Physicochemical properties of spandex-covered yarn

Spandex-covered yarn is an elastic yarn formed by spirally wrapping elongated spandex filaments with filament or staple fiber yarns as the core. One of its most distinctive characteristics is the untwisted core filament.

The cohesion between the spandex filaments and the outer covering layer in covered yarn is significantly lower than in core-spun yarn and twisted yarn, resulting in higher elasticity. Its elongation can reach 200% (double-covered yarn), achieving approximately 50% elasticity in high-elastic fabrics.

Covered yarn has a stiffer hand feel than core-spun yarn, and its strength is directly proportional to the strength of the outer covering filament or yarn, thus exceeding the strength of core-spun yarn of the same specification. Covered yarn exhibits core exposure when under tension, making it unsuitable for dark-colored products.

Covered yarn is loosely wound, with a take-up rate typically ranging from 60% to 95% depending on the application. This significantly impacts weaving process parameters.

Depending on the processing equipment, spandex covered yarn can be divided into mechanically covered yarn and air-covered yarn. Mechanically covered yarn fabrics have a flat and crisp appearance, while air-covered yarn fabrics have a soft and smooth feel.