The Filter Pressure Value (FPV) test method is a new standard for characterizing the dispersion performance of masterbatches that is being promoted and implemented in Europe (EN 13900-5). The basic principle of this method is as follows: agglomerated particles of masterbatch that are not fully dispersed during plastification will inevitably clog the filter screen when passing through it, resulting in an increase in melt pressure upstream of the filter screen. Under the same process conditions, the poorer the dispersion of the masterbatch, the faster and higher the melt pressure upstream of the filter screen will rise. Conversely, the smaller the FPV value, the better the dispersion performance.

The standard testing procedure is as follows: first, feed the extruder with pure polymer base material without any masterbatch for a period of time, and record the baseline pressure at the extrusion die head. Then add masterbatch to the polymer material and co-extrude them; as undispersed pigments or other additives clog the downstream side of the filter screen, record the fluctuations in die head pressure. This test method integrates the relationship between time and pressure peaks. After a certain period, feed the extruder with fresh pure polymer material again, and record the onset and disappearance stages of the pressure zone, at which point the entire testing process is completed.