PVC is a multi-component plastic that can be molded and processed in a variety of ways, with a wide variety of products and a wide range of uses. Through the best combination of resin and additives to meet the molding processing and use conditions, the ideal product can be obtained. To do this, it is necessary to understand the type of PVC, processing characteristics and the relationship between molding and products. For example, suspension PVC resin is often used for extrusion, injection molding, calendering, pressing, and blow molding; emulsion PVC resin is often used for molding, dipping, slush molding, etc.

1. The thermal stability of the molding process, PVC will decompose at 140°C, which brings great difficulties to the molding process. Therefore, the stabilizer must be heated to increase the decomposition temperature during the molding process. Generally, the decomposition temperature after heating the stabilizer can reach 200°C. Even so, it is not suitable to use too high temperature in the molding process, and staying at high temperature for too long will cause PVC The phenomenon of thermal decomposition.

2. In order to reduce the viscosity of the PVC melt, it should not just increase the temperature to cause it to decompose, but also increase the pressure and increase the shear rate to improve its fluidity.

3. Melt plasticization characteristics In the molding process, PVC has a slow melting speed and low melt strength, which can easily cause melt flow defects. It is often necessary to add processing modifiers to overcome these shortcomings and speed up the resin in the plasticization process. The gelation speed of the product can improve the fluidity of the melt to achieve the purpose of improving the quality of the product.

Adaptability of processing equipment, PVC is a heat-sensitive resin, which is easily thermally decomposed during molding. Therefore, in addition to adding stabilizers, the molding processing equipment should have the characteristics of avoiding long-term heating of the material and facilitating the flow of the melt, so as to ensure the normal processing of pvc products.