For PVC foamed boards, lubricants such as polyvinyl chloride need to be added during processing. Especially for PVC foamed rigid products, the role of the lubricant is almost similar to that of heat stabilizers. A good lubricant not only improves the lubricity of the resin, but also generally improves the luster, increases gloss, antistatic, promotes melting, avoids degradation, increases product toughness, reduces processing energy consumption, and improves production due to improved processing fluidity. Processing rate, etc. Therefore, in the plastic processing industry, the lubrication system is often very important.
We may not know that when using PVC foam board, its lubrication and processing fluidity require us to use the correct lubricant for it. This lubricant is generally similar to a thermal stabilizer. It all has such a function, let's take a look below.
Plastic lubricants can be divided into internal lubricants and external lubricants according to their mode of action. The internal lubricant is used to reduce the cohesive force between polymer molecular chains, and has the effects of accelerating melting, reducing melt viscosity, extending processing life, improving fluidity and improving transparency. The external lubricant functions to prevent the molten polymer from adhering to the surface of the thermal processing equipment.
Therefore, the inner and outer lubricants of PVC foamed boards have different functions during processing and it is difficult to replace each other. If lubricants only require their internal lubrication, their selection is simple, but in most cases they need to be adjusted to a certain degree. The internal and external lubricating function of a lubricant is determined by its chemical composition and its solubility in polymer melts. For example, monoglyceryl stearate can be dissolved in the melt of polyvinyl chloride, and has a part of internal lubrication, its internal lubrication function comes from the action of two hydroxyl groups in the molecule. Glyceryl tristearate has only external lubrication because it has no hydroxyl groups in the molecule. Of course, the lubrication function is also affected by impurities and other additives contained in the lubricant.
