To illustrate the different requirements of silicone powder plastic lubricants at various stages of plastic processing, taking PVC extrusion as an example, the main roles of internal and external lubricants in various parts of the processing machinery are explained.
Extruders can be divided into three lubrication effect zones:
1. Initial Lubrication Effect Zone A: This is the area from the feeding section to the compression section. PVC starts to plastify in this area. Silicone powder is required to increase plastic fluidity and ensure smooth feeding. Therefore, internal lubricants mainly work in this area.
2. Mid-term Lubrication Effect Zone B: This is the area from the compression section to the measuring section. PVC powder plastifies here. During this process, silicone powder needs to reduce friction in the plastic flow process, ensuring melt flow. External lubricants mainly work in this area, and they can reduce melt viscosity, which is also indispensable.
3. Late Lubrication Effect Zone C: This is the area from the measuring section to the metal mold. Here, the melt is compressed and sent into the mold for forming. Silicone powder needs to reduce the adhesion between the melt and the metal mold surface, facilitating demolding, so external lubricants still play a major role.
Due to the inseparable nature of the processing process, lubricants with both internal and external lubrication functions or composite lubricants are generally used. Silicone powder plastic lubricants are highly efficient lubricants with both internal and external lubrication functions.
