Production of UHMWPE sheet materials
AssigneeQuadrant Epp AG
InventorsJoseph V. Gregg, Wesley Allen Kohler, Lyle D. Berning
Life of this patent
Estimating the term…
Abstract
Wide panels of UHMWPE having exceptional flatness and surface quality are ram extruded through a slit die equipped with a plurality of individually adjustable cooling zones proximate the panel exit slit and transverse to the machine direction, which cool the panel while the panel is restrained by a back pressure device and preferably a vertical movement restraint. The process is robust and can be run for long product campaigns.
Claims35
An apparatus for ram extruding an UHMWPE panel of uniform thickness with a width greater than 0.4 m, the apparatus comprising:
- a) a slit die having a top portion and a bottom portion defining a slit therebetween, a panel exit slit on an exit face thereof, and a ram entrance slit on an inlet face thereof, the slit having a width greater than 0.4 m, the width corresponding to the width of the UHMWPE panel;
- b) a UHMWPE powder supply passage communicating with the slit of the slit die proximate the entrance slit thereof and containing UHMWPE powder;
- c) a ram having a tongue shaped so as to enter the entrance slit of the slit die;
- d) a plurality of independently adjustable transverse cooling zones positioned across the width of both the top portion and bottom portion of the slit die proximate the exit slit thereof;
- e) at least one heating zone positioned between the entrance slit and the transverse cooling zones;
- and
- f) a back pressure device located downstream from the exit slit in the machine direction, which restrains movement of an extruded panel away from the slit die,
- wherein the apparatus is used for ram extrusion of UHMWPE.
An apparatus for ram extruding an UHMWPE panel of uniform thickness and a width greater than 0.4 m comprising:
- a) a slit die having a top portion and a bottom portion defining a slit therebetween, a panel exit slit on an exit face thereof, and a ram entrance slit on an inlet face thereof the width of the slit corresponding to the width of the UHMWPE panel;
- b) a UHMWPE powder supply passage communicating with the slit of the slit die proximate the entrance slit thereof;
- c) a ram having a tongue shaped so as to enter the entrance slit of the slit die;
- d) a plurality of independently adjustable transverse cooling zones positioned across the width of both the top portion and bottom portion of the slit die proximate the exit slit thereof;
- e) at least one heating zone positioned between the entrance slit and the transverse cooling zones;
- f) a back pressure device, located downstream from the panel exit slit in the machine direction, which restrains movement of an extruded panel away from the slit die;
- g) a vertical movement restraining apparatus downstream from the back pressure device;
- and
- h) pressurizable side guides positioned so as to bear against opposing edges of a panel exiting the slit die to maintain parallelism of the panel with respect to the machine direction.
Dependencies are inferred from the claim text.