The shrinkage control of PP plastics is an important aspect of PP modification. Good shrinkage control / control is of great significance to the popularization and application of PP modified materials. In particular, the application of modified polypropylene instead of traditional engineering plastics, shrinkage is very important. In the process of modification, what factors affect the shrinkage of PP plastics?
The main mineral additives used in the modification of PP plastics are calcium carbonate, talc powder, mica powder, etc., which have obvious effect on the molding shrinkage of PP plastics. It is mainly reflected in three aspects: the first is that the mineral filler itself does not shrink, and its addition reduces the shrinkage of polypropylene modified material from the overall proportion; the second is that the addition of mineral filler will inevitably affect the crystallinity of polypropylene, thus affecting the shrinkage; Third, the addition of fine mineral agent acts as a nucleating agent, which changes the structural state of polypropylene. The formation of enlarged spherulites also affects the molding shrinkage of polypropylene.