Production principle of
EPP material
Generally, EPP beads should be loaded in the pressure tank (even if the beads are filled with air with a certain pressure), and then compressed air is injected into the mold of EPP forming machine through spray gun. Steam is introduced to further expand the EPP beads and fuse them together. After cooling, the mold is stabilized at a certain temperature to obtain EPP products.
Raw materials for
EPP material
Instead of general polypropylene (PP), high melt strength polypropylene (HMSPP) is used.
Generally, the molecule of PP is plain (without branching) and must undergo certain post-treatment to turn its molecule into branching, which is commonly known as PP grafting (the general grafting will degrade and can not achieve the purpose of high viscosity and high melt strength). It is known that Nordic chemical and Bassel can produce HMSPP.