Polyurethane Fibers (Spandex)
Properties
Polyurethane fibers, sometimes called Spandex or Elastane, are synthetic fibers in which the fiber forming substance is a polymer consisting of at least 85 percent segmented polyurethane. The fiber is produced by reacting a polyester polyol with a diisocyanate.
Spandex (Elastane) has elastomeric, rubberlike qualities and is very durable. In fact, it is even more durable than rubber and can be stretched more than 500 percent without breaking. It has good chemical resistance to many diluted acids and alkalis, but some may damage the fiber. Its strength is rather low when compared to most other synthetic fibers and its heat resistance can vary considerably depending on the composition. The fiber has excellent resistance to mildew and does not shrink when exposed to water.
| Tensile Strength (Tenacity) | Poor |
| Abrasion Resistance | Excellent |
| Absorbency | Fair - Good |
| Static Resistance | Good |
| Heat Resistance | Poor |
| Wrinkle Resistance | Excellent |
| Resistance to Sunlight | Very Good |
| Elasticity | Excellent |
| Flame Resistance | Burns Slowly |
| Resilience | Very Good |
CoMMERCIAL Spandex Fibers
Major manufacturers of urethane fibers are Indorama, Invista and Asahi-Kasei.
Applications
Thermoplastic polyurethane elastomers are molded and shaped into many different parts. Most of these elastomers can also be spun into fibers. They are typically used in combination with natural and synthetic fibers to impart elasticity in knitted and woven textiles such as sock tops, bras, support hoses, weatherproof clothing, swimsuits, and other athletic apparel.