For PVC foam sheet, calcium carbonate filler affect foaming performance is complex, mainly depends on the size of the calcium carbonate, adding amount, dispersity and moisture content, if these factors are of calcium carbonate used properly can promote foaming, otherwise will seriously affect the foaming.

    Calcium carbonate can promote foaming for two reasons: first, calcium carbonate can be used as a nucleating agent to adsorb foaming gas to form bubble nuclei, control the number of bubble holes, and make PVC bubble pore size; 2 it is calcium carbonate can improve the performance of the melt on the PVC, its rigid larger calcium carbonate can slow melt the movement and deformation ability, which can inhibit the bubble hole rapidly expanding, a finer control of bubble size of holes.