聚氨酯（PU，PUR，优力胶）是什么？
polyurethane( also named PU or PUR), is a polymer resin, which is composed of organic units joined by carbamate (urethane) links. polyurethane can be easily made into different forms, that means foam，coating or elastomer of different hardness and performance. rigid polyurethane are widely used different industries from agriculture, general machinery, manufacturing, automobile production, offshore engineering, aviation and so on.
