Process for forming an expanded porous tetrafluoroethylene polymer
US5098625A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 1990 |
| Grant date | Mar 24, 1992 |
| Priority date | — |
| Expiry date | Dec 17, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/055
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A process for preparing an improved expanded porous polytetrafluorethylene product having a higher density and improved cold flow properties and prepared from a paste formed from a polytetrafluoroethylene resin and a lubricant. The method includes extruding the paste through an extrusion die at a reduction ratio of less than 100, calendering the extrudate, removing the lubricant, and heating the extrudate to a temperature greater than the crystalline melting point of polytetrafluoroethylene but generally below the temperature at which thermal decomposition becomes appreciable while concurrently expanding the extrudate to at least twice its original length.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.