TIME：2024-01-02 hits：700
The pure resin of PVC is prone to decomposition, poor flowability, low impact strength, and poor weather resistance during processing. Therefore, various auxiliary materials need to be added during the processing to improve its performance. Such as lubricants, heat stabilizers, impact modifiers, processing aids, etc. PVC is one of the world's five major general-purpose plastics. In recent years, with the rapid development of China's national economy, PVC products have grown at a rate of over 20% annually.
The main functions of PVC processing aids are as follows: firstly, they can accelerate the plasticization process of PVC; secondly, they can improve the rheological properties of thermoplastic melts; thirdly, processing aids can improve the mechanical properties of melts in the thermoelastic state; and finally, they can improve the overall functions of products such as appearance quality. When PVC resin is heated and melts under a certain shear force, the processing aids first melt and adhere to the surface of PVC resin particles, increasing the viscosity and friction of PVC, effectively transferring shear force and heat, and accelerating PVC melting; PVC processing aids can improve the flow properties of PVC melt, such as poor strength, poor ductility, and melt fracture. The principle is to increase the viscoelasticity of PVC melt, thereby improving mold expansion and increasing melt strength. Secondly, first melt the compatible part of the processing aids with PVC to promote melting, while the incompatible part with PVC migrates outside the molten resin system, thereby improving demolding performance. Although the amount of PVC processing aids added is small, usually a few percent or even a few thousandths of the weight of the polymer, they have a significant effect and are very important for improving the processing performance of PVC.
