Calcium carbonate has remarkably higher thermal conductivity as compared to the polymer (6 and 14 times higher than those of HDPE and PP respectively). This means that the heat generated during plastic processing is transmitted through the mixture more quickly allowing faster heat transfer in extruder (faster melting & more homogeneous melt temperature), leading to potential energy savings during extrusion.
At the same time, the heat will also be conducted away faster during cooling allowing faster cooling after the die. As a general rule (not considering different thicknesses), the higher calcium carbonate concentration, the lower the cooling times.
As a result, output/throughput can be increased both in extrusion and injection moulding (with reducing cycle time).