US Patent 7803450 Production of UHMWPE sheet materials

UHMWPE panels of large width may be prepared by a continuous ram extrusion process by employing a slit die which preferably narrows from both sides in a direction transverse to the machine direction, and/or which employs a plurality of transversely positioned cooling zones located on the top and the bottom of the die, proximate the exit thereof. The panel exits the die at a temperature lower than the crystalline melt temperature.