Today we are going to show you how to foam PP thermoplastic sheet by expandable microspheres. After foaming, we will do the thermoforming to check foamed sheet will be destroyed or not under high pressure and heating.
The temperatures setting of the extrusion are from 190C to 230C, the first section of screw has lowest temp and the mold has the highest temp. The temperatures setting from low to high will be most beneficial for expandable microspheres to expand. The microspheres won’t expand until they goes out of the mold, as the pressure of the screw is very high which will limit the expansion.
After expansion, the color of PP thermoplastic sheet changes from transparent to nontransparent as microspheres are white and nontransparent hollow structure. The sheet also has the matting surface.
The density of the sheet decrease from 1100kg/m3 to 900kg/m3, with 1% dosage of expandable microspheres.
The setting of thermofoaming is 300C, 2bar, 10s. After process, the density of the pp themoplastic is almost the same as before.
The foamed sheet has the following advantages,
Heat and sould insulation;
Anti-slip and mat surface;
Lightweight;
It can be applied in packing materials, advertising materials and stationery, etc..
For more applications, please check our application sections:
https://www.expandablemicrosphere.com/applications
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