Maro Publications

Ultrahigh Molecular Weight Polyethylene
(UHMWPE)

Patents with Abstracts

*6/8/2012

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Patents with Abstracts

5. 8,304,064 
Stretch-formed sheet of ultra-high molecular weight polyolefin having excellent transparency and mechanical properties, and production method thereof
 
Takeyama and Mayama of Asahi Kasei Chemicals Corporation, Japan, developed a stretch-formed sheet of ultra-high molecular weight polyolefin having excellent transparency and mechanical properties, while being relatively thick.  A stretch-formed sheet of ultra-high molecular weight polyolefin having a thickness of 0.2 mm or greater and having an internal haze of 70% or less in the direction of the thickness, is prepared by stretching at least in one direction a formed article of ultra-high molecular weight olefin having a density of 925 kg/m.sup.3 or less and containing a polymer of ultra-high molecular weight polyolefin having an intrinsic viscosity of 7 dl/g or greater as measured in a 135 C. decalin solution, at a temperature of less than the melting point (Tm) of the ultra-high molecular weight polyolefin and at ordinary temperature or higher. (RDC 12/22/2012)

4. 8,188,207 
Process for producing high strength polyethylene film
 
Backer, Kranz and Slager of Novameer, Netherlands, formed high strength polyethylene films or tapes by skiving a block of disentangled UHMWPE.  This block is prepared by compacting  disentangled polyethylene powder at a temperature between the .alpha.-relaxation temperature and the melting temperature of the disentangled polyethylene.  The film is drawn in a single or multi stage drawing step at a total draw ratio of at least 1:20. (RDC 6/8/2012)

3. 8,178,594 
Antioxidant stabilized crosslinked ultra-high molecular weight polyethylene for medical device applications
 
Rufner et al of Zimmer, Indiana, combined an antioxidant such as tocopherol with UHMWPE prior to crosslinking irradiation.  After the antioxidant is combined with the UHMWPE, the resulting blend may be formed into slabs, bar stock, and/or incorporated into a substrate, such as a metal, for example.  The resulting product may, then, be subjected to crosslinking irradiation. In one exemplary embodiment, the UHMWPE blend is preheated prior to subjecting the same to crosslinking irradiation.  Once irradiated, the UHMWPE blended product may be machined, packaged, and sterilized in accordance with conventional techniques. (RDC 5/29/2012)

2. 8,137,608 
Crosslinked polymeric material with enhanced strength and process for manufacturing
 
Schroeder et al of Biomet Manufacturing, Indiana, developed a radiation crosslinked (50 kGy), pressure-treated UHMWPE material by applying compressive force on a crosslinked polymer in a direction orthogonal to an axial direction.  The deformed material is then cooled while held in a deformed state.  The resulting material is anisotropic, with enhanced strength oriented along the axial direction.  The directionally engineered material is oxidatively stable even after four weeks of accelerated aging in a pressure vessel containing five atmospheres of oxygen (ASTM F2003). Because of its oxidative stability, the deformation processed material is a suitable candidate for air-permeable packaging and gas sterilization, which has thus far been reserved for remelted highly crosslinked UHMWPEs.  (RDC 5/14/2012)

1. 8,129,440  s
Antioxidant stabilized crosslinked ultra-high molecular weight polyethylene for medical device applications
 
An antioxidant combined with UHMWPE prior to subjecting the UHMWPE to crosslinking irradiation. In one exemplary embodiment, the antioxidant is tocopherol. After the antioxidant is combined with the UHMWPE, the resulting blend may be formed into slabs, bar stock, and/or incorporated into a substrate, such as a metal, for example. The resulting product may then be subjected to crosslinking irradiation. In one exemplary embodiment, the UHMWPE blend is preheated prior to subjecting the same to crosslinking irradiation. Once irradiated, the UHMWPE blended product may be machined, packaged, and sterilized in accordance with conventional techniques. (RDC 4/19/2012)

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Roger D. Corneliussen
Editor
www.maropolymeronline.com

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Copyright 2012 by Roger D. Corneliussen.
No part of this transmission is to be duplicated in any manner or forwarded by electronic mail without the express written permission of Roger D. Corneliussen
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* Date of latest addition; date of first entry is 4/19/2012.