1. Concept: Foam is a kind of plastic with numerous tiny pores inside, which has the properties of softness, heat insulation, sound absorption and cushioning. 2. Classification: According to the degree of softness and hardness, it is divided into soft, semi-rigid and rigid foam plastics; according to the bubble structure, it can be divided into open-cell foam and closed-cell foam. Open-cell foam refers to the cells communicating with each other and venting each other; it is characterized by good sound absorption and cushioning properties; closed-cell plastic means that the cells are not interconnected and are not related to each other; Low thermal conductivity, low water absorption, and floating. 3. Uses: Foam plastics are widely used in sound insulation, insulation, insulation, insulation, shockproof, filtration, packaging and other materials. Low-foamed foams such as polyurethane, polystyrene, and polyvinyl chloride can be used as substitutes for wood; polyethylene, polystyrene, and polyvinyl chloride foam paper can be printed on special documents, maps, or made into cardboard. Building materials such as packaging and ceilings. In addition, the composite material of foam and fiber, such as foam artificial leather, synthetic leather, etc., is soft and full, and can be used as a substitute for leather to make shoes, caps, boxes, bags, gloves, and the like. Ball Valves,Flange Type Ball Valve,Flanged Ball Valve,Platform Flanged Ball Valve ZHITONG PIPE VALVE TECHNOLOGY CO.,LTD , https://www.ztpipevalve.com