Lastex

Lastex is a type of elastic yarn or fabric made with a core of rubber or synthetic elastomer wrapped with threads of another fiber, such as cotton, rayon, silk, or nylon. The wrapping fiber protects the elastic core, improving durability, comfort, and appearance.

Lastex was primarily used in the manufacture of clothing and other textiles where elasticity and stretch are desired. Common applications included swimwear, foundation garments (like girdles and bras), hosiery, sportswear, and waistbands. The wrapping provides a more textile-like appearance than bare rubber and allows the material to be dyed and finished like other fabrics.

While the term "Lastex" was once widely used as a generic term for elastic yarns of this construction, it was originally a trademarked brand name of the United States Rubber Company (later Uniroyal). Due to the rise of alternative elastic materials and changes in manufacturing, the use of Lastex as a primary material has declined significantly. Materials using similar construction techniques with different synthetic elastomers like Spandex (also known as elastane) are more commonly used today. However, the principle of an elastic core wrapped with other fibers remains a common method for producing elastic textiles.