Extruder with roller die

摘要

An extruder with a roller die in which a plastic or rubber material fed from a mixer is formed into a sheet by a roller die located at the fore end of a screw feeder which includes a cylinder and a revolving screw, the screw feeder employing a short screw shaft which has its base portion rotatably supported in the cylinder and a non-contacting screw portion essentially including a feed portion and a compression portion and disposed in the cylinder with a small gap being formed between the screw portion and the inner periphery of the cylinder. The pressure distribution in the screw feeder is controlled such that the maximum pressure in a compression zone and the pressure at the fore end of the cylinder are maintained in the ranges of 52x103 to 200x103 gr/cm2 and 20x103 to 60x103 gr/cm2, respectively.