Remote fluorination of fibrous filter webs
US10464001B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 21, 2016 |
| Grant date | Nov 5, 2019 |
| Priority date | — |
| Expiry date | Aug 16, 2037 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T442/68
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method of making a fluorinated fibrous web, which method includes providing a nonwoven web 22 that contains polymeric fibers, creating a plasma that contains fluorine atoms at a first location 14, and contacting the nonwoven web with products from the plasma at a second location 26 remote from the first location 14. The method avoids exposure of the web to the plasma and hence expands the manufacturing processing window. Webs so fluorinated have a different C3F4H+ to C2F5+ ratio when compared to locally fluorinated webs having similar levels of surface fluorination. The remote fluorinated webs can be subsequently charged electrically to provide a good performing electret filter 40 suitable for use in an air purifying respirator 30. Webs fluorinated in accordance with this invention also may exhibit good performance even after being “aged” at high temperatures.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.