Method for producing filled, modified and fibre reinforced thermoplastics and twin-screw-extruder for carrying out the method

摘要

Using a co-rotating twin-shaft, dual-screw extruder (2), polymer and polymer blend are dosed into the induction zone (5), to become melted together and mixed in the melt zone. Filler is added whilst mixing and kneading. Fiber rovings (12) are drawn in. They are cut to mean lengths of 1.0 mm In a mixing zone and blended-in. Vacuum degasification follows. The product is then removed. An Independent claim is included for the corresponding dual screw extruder. Preferred features: From the point of filler addition, against the conveying direction (5), atmospheric back de-aeration is carried out. Between filler and rovings addition, atmospheric degasification is effected. When making granules, the fibers are cut to a mean length of 1.5-0.4 mm. When making strips or profiles the fibers are cut to a mean length of 10-50 mm. Before addition they are coated with some of the polymer. The equipment used, includes zones and addition points as indicated. It also includes an injection nozzle with a constriction in the channel immediately ahead of its outlet, the conical angle of constriction being 30 degrees . Diameter ratios are cited. An impregnation unit for fiber rovings precedes their induction point.