Why choose nano calcium carbonate as filler of pvc pipe and profile?

The difference between nano calcium carbonate and ordinary calcium carbonate

Item                                  nano CaCO3      Precipitated CaCO3      Natural CaCO3
Primary particle size          1-100nm                   1-10μm                          > 1μm
Particle shape                  controllable               spindle shape        irregular, uncontrollable 
Surface modification                Yes                             No                              No
Dispersity                          Good dispersity    Poor dispersity        Very poor dispersity
Function                              Functional filler                Filler                           Filler

Practice has proved that PVC pipe and profile filled with nano calcium carbonate, the impact strength and tensile strength was significantly improved, the appearance of product and processing performance has also been improved.