1. Cotton yarn: Cotton is a herbaceous plant that is harvested once a year. The fiber of cotton is mainly cellulose, containing a small amount of sugar, protein, fat, and other accompanying organisms. The cotton yarn has a circular cavity, which has better thermal insulation performance than price. Advantages: Cotton woven seamless underwear is comfortable, breathable, and warm to wear. Disadvantages: Cotton has poor elasticity and is prone to wrinkling and deformation. According to the characteristics of cotton, in order to improve the width and shape retention of cotton, seamless underwear will be remade with cotton yarn and other fiber yarns woven together to improve the shape retention of underwear. 2. Silk: Silk is mainly produced by southern domesticated silkworms, which are mainly composed of protein, fibroin, and sericin. Advantages: Silk is a high-quality underwear material that is soft, smooth, elastic, shiny, and has good moisture absorption. Disadvantages: Poor resistance to sunlight, acid, and alkali, making it difficult to maintain. 2. Regenerated fibers: Viscose belongs to the category of regenerated cellulose fiber yarn. The raw materials are cotton linter, wood, dried plants, etc., which are alkalized and then react with carbon dioxide to form cellulose. It is dissolved in a dilute alkaline solution to obtain a viscous solution - viscose spinning solution, which is then processed into viscose filaments through a series of processes. Advantages: Viscose woven fa