Patent ID: 6419864
Filing Date: 2002-07-16
Classification: B29B,B29C,B29K

Abstract:
A method of preparing filled, modified and fiber reinforced thermoplastics by mixing polymers, blend polymers, fillers and fibers, comprising the following steps:providing a twin screw extruder (2) having shafts (23, 24) that are drivable to rotate in the same direction, a conveying direction (5), a feed zone (25), a melting zone (27), a filler feed zone (31), a filler incorporation zone, a fiber feed zone (34), a fiber incorporation zone (36), a vent zone, and a discharge zone; feeding metered polymer and blend polymer to said feed zone (25); melting and mixing said polymer and blend polymer in said melting zone (27); feeding filler into a filler feed zone (31); mixing and kneading in said filler incorporation zone; providing at least one of providing reverse atmospheric venting from the feeding of the fillers counter to the conveying direction (5) and performing atmospheric venting and degassing between the incorporation of the filler and the feeding of the fiber rovings (12); feeding fiber rovings (12) into said fiber feed zone (34); cutting said fibers to long fiber sections of an average length of 1.5 to 4.0 mm and incorporating said long fiber sections in said fiber incorporation zone (36) into said mixed and kneaded polymer, blend polymer and filler; degassing by vacuum in said vent zone; and discharging filled, modified and longfiber reinforced thermoplastic in said discharge zone.