Patent ID: 6309574
Filing Date: 2001-10-30
Classification: B29B,B29C,B29K,B29L,B32B,F16L,Y10T

Abstract:
A method for manufacturing an extrudable product comprising:(a) providing an apparatus including an extruder comprising at least one rotor with first grooves, at least one stator with second grooves and a clearance between the rotor and the stator, said first grooves, second grooves and clearance forming a processing cavity having a volume that consists of the volumes of the first grooves, the second grooves and the clearance, said processing cavity having a cross-sectional area that decreases continuously along at least a part of an axis of the extruder, said extruder further comprising supply means for feeding a material to be extruded into the processing cavity;b) feeding the material to be extruded in a powder, pellet or granulate form into the processing cavity through the supply means and causing rotation of the rotor relative to the stator such that the material is forced to proceed along an x-axis in a shear zone of the extruder where the material is subjected to a shear which causes a frictional heat that melts a part of the material and forms a bed consisting of mainly unmelted particles and melt around the particles, said processing cavity being completely filled at a cross-sectional portion thereof that is a distance from the end of the extruder, said unmelted particles being present in the cross-sectional portion, so as to raise pressure in the extruder to a level that is higher than that needed for pushing the material further along the x-axis through a die.