What Is The Elasticity Principle Of Air-encased Yarn?

The elasticity of air-encased yarn primarily stems from its unique structure. It uses a highly elastic spandex core yarn, with an outer layer of nylon, polyester, and other filaments wrapped through an air-encasing process. Spandex yarn itself possesses excellent elasticity, with its molecular chains composed of flexible and rigid segments. The flexible segments give spandex yarn its stretchability. When subjected to external forces, the molecular chains stretch; when the force is removed, they return to their original shape through intermolecular forces. The outer filaments act to restrain and protect the spandex yarn, and also influence the overall elastic properties of the air-encased yarn. During the stretching process, the spandex yarn is stretched, and the outer filaments adjust their wrapping pattern as the spandex yarn stretches, maintaining a stable yarn structure. For example, when clothing is worn, human movement causes the clothing to be stretched, and the spandex filaments in the air-coated yarn stretch. Although the outer filaments themselves are not as elastic as spandex, they can change the winding angle and spacing to cooperate with the deformation of the spandex filaments to keep the yarn continuous as a whole. After the stretching force is removed, the spandex filaments rebound, driving the outer filaments to reset, allowing the clothing to return to its original shape, achieving good elastic recovery performance, meeting the clothing's requirements for elasticity and comfort, and is widely used in elastic clothing such as tights and swimsuits.