High loading carbon black masterbatch for pressure pipe applications

摘要

A masterbatch for pressure pipe applications is disclosed. The masterbatch includes carbon black in a concentration that is in excess of 40 weight percent (wt %) of the masterbatch, and a high-density polyethylene (HDPE) carrier resin in a concentration that is in the range of 40 to 60 wt % of the masterbatch and has a melt flow index above 100 g/10 min at 2.16 kg/190° C. and a weight average molecular weight (Mw) that is less than 100000. The masterbatch may further include one or more additives (e.g., lubricant and/or an anti-oxidant). In some embodiments, microdispersion of carbon black in the masterbatch is rated less than 3 (according to ISO 18553). In one specific case, 98% or more of observed carbon black agglomerates are less than 30 microns. The masterbatch may be included, for example, in a pressure pipe compound where it is diluted with a base polymer.