Patent ID: 7758797

Claim:
A ram extrusion process for preparing UHMWPE panels of widths greater than 0.6 m as extruded, comprising: providing a slit die having a width of greater than 0.6 m which has a substantially rectangular cross-section under ram extrusion operating pressure, the die having a top portion and a bottom portion and an inlet face and an exit face, and having at least three independently controllable cooling zones in each of the top portion and bottom portion, said cooling zones located proximate the exit face of the die, and positioned along the width of the die, such that the temperature of each respective cooling zone may be adjusted to vary the temperature of respective portions of the die transverse to the exit face; incrementally introducing UHMWPE resin particles into the die under pressure from a ram; heating the UHMWPE particles to a temperature above the crystalline melt temperature of UHMWPE to form a substantially continuous molten thermoplastic; cooling the UHMWPE to a temperature below the crystalline melt temperature while within the die and while maintaining contact with the walls of the die; and obtaining a solidified UHMWPE panel product which has exited the die.