The main raw materials for the production of PVC foam board are: PVC resin, stabilizer, foaming regulator, foaming agent, pigment, filler, PVC resin: this is the most important raw material, foamed substrate, PVC foam production. The plate is generally made of P-700 PVC resin. The gelation speed is fast during processing, the processing temperature is relatively low, the product quality is stable, and the density is easy to control. In the production of crust foamed PVC sheet, in order to improve product quality and strictly control the fluctuation of product density and thickness, P-700 type ethylene method PVC resin is often used. In the production of free-foamed PVC sheet, from the consideration of reducing production cost, many manufacturers have adopted the calcium carbide method P-700 type PVC resin stabilizer: in the production process of PVC foamed sheet, in order to fully plasticize the material, the material The temperature is higher; and the plate mold has a wide cross section and a long flow path, especially the shape of the crust foaming plate mold is long, and the foaming agent also generates decomposition heat during the decomposition process, and these factors require that the stabilizer must have Sufficient thermal stability to ensure product quality and long-term stable production.