PROSTHESIS PARTS AND THEIR PRODUCTION

摘要

PROBLEM TO BE SOLVED: To make it possible to enhance the wear resistance of biologically transplantable polymer parts by exposing a blank in a sealed package not containing oxygen to gamma rays, raising the temperature of the blank to a high-temperature threshold lower than a melting point and maintaining this temperature. SOLUTION: The wear surface blank formed from polymer raw material is prepared when the prosthesis wear surface parts formed from the irradiation- crosslinked polymer raw material are produced. The blank existing in the sealed package not containing the oxygen is exposed to the gamma rays of the dosage effective for substantially introducing the crosslinking of the desired effective level into the polymer raw material. The temperature of the blank is raised up to the high-temperature threshold lower than the melting point in the state of allowing the blank to remain in the sealed package, by which the residual free radicals are decreased and the polymer raw material is stabilized. The resistivity to the deterioration in oxidation with the lapse of time is thus enhanced and the high-temperature threshold is maintained for the period effective for not substantially changing the crosslinking level.