Patent ID: 7132025
Filing Date: 2006-11-07
Classification: B29B,B29C,D04H

Abstract:
1. A continuous process for producing a thermoformable fiber reinforced semifinished product, comprising the following steps in the order given: a) dry blending from 10 to 80 percent by weight of thermoplastic fibers having an average length of between 20 mm and 80 mm with from 90 to 20 weight percent of reinforcing fibers comprising at least one of glass fibers and carbon fibers by an airlay or carding process to form a continuous non-woven web, said weight percents based upon the total weight of the web, said reinforcing fibers having an average length of from 10 to 60 mm; b) needling the web with felting needles to provide a needled web having an increased orientation of reinforcing fibers perpendicular to the surface of the needled web; c) heating the consolidated web to a temperature above the softening point of the thermoplastic fibers to form a heated web; d) compressing the heated web in a continuous fashion at a pressure of from 1 to 10 bar to provide a compressed and partially consolidated thermoformable semifinished product having a thickness greater than 3 mm, wherein the thermoplastic is polypropylene having a melt viscosity MFI (230° C., 2.16 kp) to DIN 73735 of greater than 300 g/10 min.