The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 04, 2011
Filed:
Apr. 09, 2010
Aiguo Wang, Wayne, NJ (US);
John H. Dumbleton, Ridgewood, NJ (US);
Aaron Essner, Bloomingdale, NJ (US);
Shi-shen Yau, Berkeley Heights, NJ (US);
Aiguo Wang, Wayne, NJ (US);
John H. Dumbleton, Ridgewood, NJ (US);
Aaron Essner, Bloomingdale, NJ (US);
Shi-Shen Yau, Berkeley Heights, NJ (US);
How medica Osteonics Corp., Mahwah, NJ (US);
Abstract
A method of producing an improved polyethylene, especially an ultra-high molecular weight polyethylene utilizes a sequential irradiation and annealing process to form a highly cross-linked polyethylene material. The use of sequential irradiation followed by sequential annealing after each irradiation allows each dose of irradiation in the series of doses to be relatively low while achieving a total dose which is sufficiently high to cross-link the material. The process may either be applied to a preformed material such as a rod or bar or sheet made from polyethylene resin or may be applied to a finished polyethylene part. If applied to a finished polyethylene part, the irradiation and annealing must be accomplished with the polyethylene material not in contact with oxygen at a concentration greater than 1% oxygen volume by volume. When applied to a preform, such as a rod, the annealing of the bulk polymer part of the rod from which the finished part is made must take place on the rod before the implant is machined therefrom and exposed to oxygen.