Pressure filter test

The pressure index (PI) is a measure of the fineness of dispersion of pigments in a masterbatch

It is carried out in a single screw extruder
400 mesh screen pack
Temperature of 200 °C
Masterbatch is let down to 10 % pigment concentration in HDPE resin
Period of 60 minutes

The pressure rise across the screen pack is measured.

PI is expressed as bar x cm2 x g-1 (Pressure rise per unit area of screen pack per gram of pigment).

Low pressure index values (PI) stand for high dispersion quality. They are a measure of processing properties of color masterbatches especially on polypropylene fiber spinning.

Pressure filter test can be evaluated after test method DIN EN 13900-5.