Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Treating polymer containing material or treating a solid...
Patent
1994-10-07
1995-09-12
Schofer, Joseph L.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Treating polymer containing material or treating a solid...
528502R, C08F 626
Patent
active
054497450
ABSTRACT:
A medical implant made of polymeric material having an increased oxidation resistance is formed by a method including the steps of placing a resin powder in a sealed container. A substantial portion of the oxygen is removed from the sealed container by either a vacuum, an oxygen absorbent or by flushing with inert gas. The container is then repressurized with a gas such as nitrogen, argon, helium or neon so that long term storage may be possible. On use, the resin is transferred to a forming device which both melts and forms the resin in an oxygen reduced atmosphere to produce a polymeric raw material such as a rod or bar stock. The medical implant is then formed from this raw material annealed and sealed in an air-tight package in an oxygen reduced atmosphere. The implant is then radiation sterilized and thereafter annealed in the package for a predetermined time and temperature sufficient to form cross-links between any free radicals in neighboring polymeric chains.
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Stark Casper F.
Sun Deh-Chuan
Akens Lawrence C.
Augustin Raymond W.
Howmedica Inc.
Richardson Peter C.
Schofer Joseph L.
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