Process for producing ultra-high molecular weight low modulus polyethylene shaped articles via controlled pressure and temperature and compositions and articles produced therefrom
US5721334A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 1996 |
| Grant date | Feb 24, 1998 |
| Priority date | — |
| Expiry date | Feb 16, 2016 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2105/251
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Shaped articles made from molded ultra high molecular weight polyethylene (UHMWPE) with an average molecular weight of between about 1 million and about 10 million and exhibiting a low modulus of elasticity throughout the shaped article or in selected regions of the shaped article are disclosed. These articles are produced by filling a mold with powdered UHMWPE, covering the mold with a piston, raising the temperature of the mold and its contents to between about 140.degree. and about 225.degree. C. while simultaneously applying a pressure of between about 2.5 and about 15 MPa to the mold and its contents, maintaining the pressure and temperature for between about 5 and about 25 minutes, with the time selected dependent upon the thickness of the molded part, then dropping the temperature of the molded part, either completely or in part at a rate between about 4.degree. and about 175.degree. C./minute either while maintaining the mold at the molding pressure, at pressure less than the molding pressure or under no external applied pressure. The shaped articles so produced exhibit a combination of properties including an elastic modules between about 500 MPA and about 800 MPA, a yield…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.