Electret process and products
US4944854A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1985 |
| Grant date | Jul 31, 1990 |
| Priority date | — |
| Expiry date | Sep 30, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2973
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Continuous processes for the preparation of electrets and the products produced thereby, including filter fabrics, are disclosed. The process employs a continuous film or continuous filaments in the form of a tightly packed warp having a warp density as determined by light transmission of not more than 40%. The continuous film or continuous filament in the form of a tightly packed warp are continuously fed one or more times through a corona charging station having electrodes disposed on both sides of the material being treated, the material being treated being simultaneously heated while being subjected to a corona discharge of from 6 KV to 20 KV direct current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.