Plasticization refers to the process of rolling or extruding raw rubber to improve its ductility, flowability, and other properties, in order to facilitate subsequent processing such as molding
1. Processing conditions:
Under normal processing conditions, the plasticization rate of PVC resin increases with the increase of processing temperature and shear rate. The higher the processing temperature, the greater the temperature difference, and the faster the heat transfer rate. Due to PVC being a poor conductor of heat, an increase in shear speed will accelerate the frictional heat generation between materials, as well as the frequency of contact between materials and equipment, thereby improving heat exchange efficiency
2. Resin structure:
The glass transition temperature and melting point of PVC increase with the increase of molecular weight and crystallinity, and the plasticization degree of PVC also becomes difficult.
3: Formula factors
The use of lubricants, plasticizers, processing aids, impact modifiers, fillers, stabilizers, etc. in the PVC processing process has a significant impact on the properties of PVC plasticization. Of course, different components have different ways and degrees of impact on the plasticization properties of PVC due to their different application purposes.
4. Mixing and processing process
Mixing is the process of homogenizing PVC resin with additives such as heat stabilizers, modifiers, lubricants, fillers, and pigments. The main equipment used is a high-speed kneading machine and a cooling mixer. The mixing process relies on the mutual friction and shear forces generated by mechanical forces on the material to refine and heat up the material, melting some additives and coating them on the surface of PVC resin. PVC resin is refined under shear and friction, and its surface appears soft and porous under temperature. The auxiliary agent is adsorbed on the surface and reaches homogenization. The temperature further increases, and the surface of the particles melts, resulting in an increase in particle density
Post time: Oct-30-2023