Process for producing multilayer polytetrafluoroethylene porous membrane
US5064593A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 6, 1990 |
| Grant date | Nov 12, 1991 |
| Priority date | — |
| Expiry date | Dec 6, 2010 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2105/04
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A process for producing a multilayer polytetrafluoroethylene porous membrane comprising at least two layers having different average pore diameters is disclosed, the process comprising the steps of: filling the inside of a cylinder of an extruding mold distinctively with at least two kinds of polytetrafluoroethylene fine powders with each of which a liquid lubricant has been mixed; subsequently paste-extruding the powders to obtain a multilayer extrudate, which is then optionally rolled; and then stretching the extrudate or the rolled extrudate at least monoaxially after the liquid lubricant is removed therefrom or without removing the liquid lubricant.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.