Calcium carbonate treated with an interfacial agent such as stearic acid or a stearate is often used in place of untreated calcium carbonate to take advantage of improved lubricity and wetting characteristics. These characteristics typically lead to lower mixing viscosity, improved filler dispersion and better flow properties.
CaCO3 filler masterbatch technologies
Most common carrier resin in calcium carbonate filler masterbatches used for PE films, shopping and garbage bags as well as many others polyolefin products is LLDPE. A typical melt flow index (MFI or MFR) of a carrier resin ranges from 10 to 20 MI. Some master batches actually show higher MFI. Lower MFIs (1 to 2 MI) are also available though.
Calcium carbonate (CaCO3) filler masterbatch (or filler master batch) is a concentrated mixture of calcium carbonate and other additives encapsulated during a heat (mainly extrusion) process into a carrier polymer resin which is then cooled and cut into granules (pellets) making CaCO3 masterbatch a solid additive for plastics. Since common CaCO3 MB was originally intended for filling plastics to replace a part of expensive carrier resin it is often called filler masterbatch or filler additive.