Twin Screw Extrusion for Long Fiber Reinforcement of TPO's

摘要

Twin screw extruders are used to compound all types of TPO compounds with chopped fibers to enhance mechanical properties of the final product. There is a trend to feed continuous fiber roving into the twin screw extruder to facilitate fiber lengths of 10mm or bnger in the end product for stronger/higher quality parts, particularly for the automotive and construction markets. An understanding of the basic functions of the twin screw extruder to continuously mix long fibers (glass, carbon, synthetic or natural) is intended to demonstrate when/how this technology can and should be applied Important design factors for a long fiber twin screw extrusion system include: 1. Recipe control of fiber ravings with carrier resins/fillers/additives 2. Fiber wetting and devolatilization while preserving fiber length 3. Pumping against die pressures in a constant manner 4. Melting and compounding of formulations in combination with fiber introduction 5. Process control from start up to steady state.