Method for manufacturing porous fluoropolymer films
US5552100A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 2, 1995 |
| Grant date | Sep 3, 1996 |
| Priority date | — |
| Expiry date | May 2, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2027/18
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method for preparing thin fluoropolymer (PTFE) films, said method generally having the steps of: a) providing an unsintered fluoropolymer film; b) pre-sintering expansion of the film; c) sintering the expanded film with dimensional restraint to prevent shrinkage; and d) post-sintering stretching of the film to a final thickness preferably less than 0.002 inches. The post-sintering stretching of the film in step d may be accomplished in a single step, or may include a series of post-sintering stretching steps. Steps b and c of the method may be carried out bypassing the calendared film through a machine direction orienter device and, thereafter, step d of the method may be accomplished by subsequently repassing the sintered film through the machine direction orienter device, one or more additional times.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.