INVESTIGATION INTO A HIGH OUTPUT POLYPROPYLENE SCREW AND ITS MIXING MECHANISM

摘要

It is known, industry wide, that polypropylene (PP) resins plasticate at reduced rates compared to other olefins. While many causes have been suggested for this problem, a solution was not. A simple, spiral fluted extensional mixer (SFEM) was first introduced for the single screw extruder (SSE) for its superior compounding. [1, 2, 3,4, 5]. A variation, the Elongator JI, hereafter SFEM II, was tested against a control screw for output. A 100% increase in output was found over a conventional screw— more than making up for PP's historically low rate.Because the SFEM series is noted for its ability to compound like a twin, we investigated mixing on the SFEM II. The investigation compares the flow to a simple computer model. A color concentrate of just 0.5% was used with frozen pullouts or carcasses showing the mixing during operation. The extrudate is examined and, even when magnified to 100X, does not show striation lines.