Polyurethane fibers, also known as Spandex or Lycra, are a type of synthetic fiber produced from polyurethane. Developed by DuPont in 1959, it went through rapid industrialization in the 1970s. It was originally called Spandex and later renamed Lycra in the United States, Elastane in Europe, Neolon in Japan and Dorlastan in Germany.

Polyurethane fibers are synthetic fibers produced from polyurethane via dry or wet spinning processes. They have elasticity due to a segmented copolymer network structure comprising “soft” and “hard” chain segments. Apart from displaying high elastic recovery and high elongation at break similar to rubber, they also exhibit excellent abrasion resistance, moisture absorption, stretchability, and antimicrobial properties. China is presently the largest producer and consumer of spandex worldwide.

I. Basic Classification

Polyurethane fibers can be categorized into polyether-based and polyester-based types based on chemical structures and properties. Polyether-based polyurethane fibers offer good hydrolysis and flexibility, along with excellent detergent resistance. In contrast, polyester-based polyurethane fibers provide better heat resistance and strength, as well as strong resistance to oxidation and oils.

Spandex fibers can be produced using various methods, while dry spinning is the most widely employed. Fibers produced through this method can exhibit non-circular cross-sections due to variations in solvent evaporation rates, yet their longitudinal surfaces consistently remain smooth.

II. Types of Fabrics

1. Synthetic Leather Fabrics: Faux leathers made from polyurethane fibers are known for their softness, abrasion resistance, waterproofness, and wrinkle resistance. They closely resemble real leather in appearance and feel, often used in clothing, footwear, and bags.
2. Faux Fur Fabrics: Faux fur fabrics made from polyurethane and polyester fibers offer high softness, comfort and warmth. With appearance and feel akin to real fur, they find use in winter apparel and home décor.
3. Stretch Fabrics: Fabrics made from polyurethane fibers and elastic fibers are soft, comfortable, and highly elastic. Their excellent flexibility and resilience make them ideal for tight-fitting clothing and sportswear.
4. Coated Fabrics: Fabrics made from polyurethane fibers with a special coating provide waterproof, oil-resistant, and stain-resistant properties. Due to durability and imperviousness, they are commonly used in raincoats, tents and luggage.

III. Applications

1. Apparel: Used in manufacturing underwear, skiwear, sportswear, swimsuits, etc.
2. Home Furnishings: Employed for making curtains, carpets, rugs, and other interior décor items.
3. Automotive Interiors: Utilized in producing automotive seats, steering wheel covers, and other car interiors.
4. Healthcare: Used in medical textiles like surgical gowns, bandages, etc.

The elasticity and comfort of polyurethane fibers make them suitable for apparel and home furnishings, while their exceptional abrasion resistance, waterproofness and antimicrobial properties extend their applications to fields like healthcare and automotive interiors.