15:37 Apr 9, 2011 

I've found this site, which certainly uses "pellets" in this context: "HDPE resin pellets are small granules usually in shape of a cylinder or a disk with a diameter of a few millimeters. These High Density Polyethylene particles are industrial raw material transported to manufacturing sites where consumer products are made by re-melting the granules and molding them into final products."

Although they also use "granules", so I think perhaps either may be OK.