China outdoor composite wood decking and other WPC Products Co-extrusion process is a kind of processing technology to produce multi-layer plastic products. Typical co-extrusion products are films and sheets. In the co-extrusion process, more than two kinds of polymers are combined in the same die after being extruded by different extrusion heads, and each polymer forms a resin layer with different properties in the finished film (sheet). Compared with other process methods for the production of multi-layer structure products, this process has more advantages not only in production cost, but also in product function. The co-extrusion technology is based on the new composite material processing technology, the use of multiple extrusion equipment, the internal polymer material is effectively combined together, and the molding operation is carried out in the machine head, forming a complete composite material product. Compared with the traditional composite process operation, the co-extrusion technology can effectively simplify the process production process, while the coating and molding technology of the product has been improved, and has the advantages of shorter molding time, lower energy consumption and more types of composite products. Therefore, the current co-extrusion technology is widely used in the production of composite films or composite pipes, and has made a significant contribution to the development of the plastic molding industry. In the plastic molding process, co-extrusion molding technology is one of the most advanced and very effective molding technology, in China's composite film and Fosun pipe production work, the supply of molding technology has a very wide range of applications, greatly improving the production efficiency of composite materials to reduce the production process of environmental pollution.