A Complete Guide to Spandex Fiber, the Core Fiber of Elastic Fabrics!

In a world where fashion and comfort go hand in hand, 100% cotton, polyester-cotton stretch woven fabrics and spandex yarns are indispensable materials. With their unique properties and versatile applications, they bring vitality and comfort to our garments. Let us explore the charm of these materials together.

Spandex fiber serves as the core fiber of stretch fabrics, and its market share has been growing steadily.

Spandex fiber is a type of elastic fiber. Elastic fibers are collectively called Spandex overseas, while its trade name in China is 氨纶 (spandex). In fact, spandex is just one major category of elastic fibers. Spandex fiber (Polyurethane Fibre), abbreviated as PU fiber, has two grades. One is a block copolymer of aromatic diisocyanate and hydroxyl-containing polyester segments, known as polyester-type spandex. The other is a block copolymer of aromatic diisocyanate and hydroxyl-containing polyether segments, known as polyether-type spandex. The representative trade name for polyester-type spandex is Vyrent; for polyether-type spandex, it is Lycra.

1. Yarn forms of spandex elastic fiber

Spandex elastic fiber is blended with other fibers to produce stretch yarns. There are three common yarn structures: spandex core-spun yarn, spandex folded-twisted yarn and spandex covered yarn. These three yarn types differ fundamentally in processing principle, structure and performance, so they also vary greatly in end use and weaving performance.

2. Key properties of spandex fiber

• Excellent elongation and recovery: It can normally stretch by over 500%–700% with outstanding elastic recovery. It recovers 97% after being stretched to 200%, and over 99% recovery at 50% elongation.
• Poor heat resistance: Short-term exposure at 95–150°C generally causes no damage to the fiber; higher temperatures will impair its elasticity. For this reason, temperatures must be controlled during dyeing and finishing to avoid loss of elasticity.
• Good dyeability: It has excellent affinity to dyestuffs and can be dyed in a wide range of colors.
• Good acid and alkali resistance.

Thanks to spandex’s good dyeability, together with the comfort and fluffy hand feel it brings to fabrics, it has secured a solid position in China’s and the global textile industry. Adding elasticity to textile fabrics has become an inevitable trend for apparel textiles.