Does MFI of filler masterbatch carrier resin matter?

Filler masterbatch carrier resin MFI

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.

CaCO3 makers' tests showed that using a carrier with close to the same viscosity as the base resin in the PP bag – 0.7 MI HDPE or 0.9 to 1.5 MI LLDPE – improves physical properties of the final product.

Matching molecular weights of carrier and PE film resins makes it possible to use the highest filler loadings.