New process of fine grinding-activation of heavy CaCO3 and its application to PVC rigid sheet

To make heavy calcium carbonate filled UHMW-PVC rigid sheet, the calcium carbonate powder is activated in a specially designed fine grinding-activation equipment (SM-10) by adding rare-earth aluminate coupling agent. The calcium carbonate powder is ground to micron order. The activated calcium carbonate filler shows excellent properties wheni t is added to UHMW-PVC, since the activated powder surface has strong compatibili ty with polymer. At a filling rate of 70 phr(per hundred resin), the impact strength with U notch is above 7 kJ/m
²
and the tensile strength is above 20 MPa. The fine grinding-activation and PVC sheet pressing process are given. Both the influence of the amount of plasticizer and coupl ing agent on the mechanical properties and the influence of fill ing rate on PVC rigid sheet are discussed.