Polyurethane (PU) is a polymer compound, which is called polyurethane. It is a macromolecular compound with repeated carbamate groups in the main chain. Polyurethane can be divided into polyester type and polyether type. Can be made into various forms of materials, including polyurethane plastics (especially foam plastics), polyurethane fibers (called spandex in China), polyurethane rubber, elastomers and so on. Polyurethane is widely used. Widely used in cold chain logistics, soft packaging, footwear, infrastructure and other fields. For example, polyurethane foam is often used in thermal insulation materials and cushioning materials, polyurethane fiber (spandex) is often used in textiles and elastic fiber products, and polyurethane rubber is often used in seals and elastic elements. Polyurethane is widely used in many industries because of its good physical properties and chemical stability.