Patent ID: 8344040
Filing Date: 2013-01-01
Classification: C08F,C08J

Abstract:
1. A process for producing an ultrahigh molecular weight polyethylene polymer with uniform chemical crosslinking, the process comprising the steps of: providing an oven adapted to control: purge gas flow into and out of the oven; purge gas flow circulation or vacuum conditions within the oven; heating rate; and cooling rate; placing a block of ultrahigh molecular weight polyethylene material into the oven, the block comprising an initial shape and a melting point and the ultrahigh molecular weight polyethylene material comprising a microstructure of carbon-carbon bonds; preheating the block to a preheating temperature above the melting point and up to about 30 degrees Centigrade above the melting point, said preheating temperature keeping bond breakage reactions inactive, and holding said preheating temperature until such time as the block has a uniform temperature with no significant change in the initial shape, said block then comprising a pre-heated block; heating the pre-heated block to a temperature above the preheating temperature and at least 30 degrees Centigrade above the melting point, said heating temperature causing carbon-carbon bond breakage within the microstructure; terminating heating of the block in the oven when a pre-determined crosslinking density level is reached; cooling the block to room temperature under an inert gas to bring the material back to a solid state; and removing any oxidized material from surface of the block to produce a block with uniform chemical crosslinking.