The main components of denim are pure cotton and blended; pure cotton is naturally 100% cotton, and blended is cotton with a small number of chemical fibers such as spandex. Denim, also known as split silk, is a thick yarn-dyed warp twill cotton fabric with dark warp yarns, usually indigo blue, and light weft yarns, usually light gray or scouring white yarn. Also known as indigo labor cloth. Originating in the western United States, it was named after the grazing staff used to make clothes and trousers.
In order to improve the elasticity of modern denim, a certain amount of spandex is added, but the content is very low, generally not more than 3%, otherwise, it will become a rubber band. Authentic denim can’t have any other ingredients.