Tetrafluoroethylene polymer, air filter medium, filter pack, and air filter unit
US12152093B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 6, 2019 |
| Grant date | Nov 26, 2024 |
| Priority date | — |
| Expiry date | Dec 6, 2039 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2327/18
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A tetrafluoroethylene polymer is provided in an air filter medium having a pressure loss that can be reduced and made uniform at a plurality of positions. The tetrafluoroethylene polymer may also be provided in an air filter medium, a filter pack, or an air filter unit. The tetrafluoroethylene polymer has drawability and non-melt processability. The tetrafluoroethylene polymer has a ratio S2/S1 of 0.60 or more, where S2 represents an endotherm mJ/mg in a range of T0° C. or higher and 350° C. or lower, T0° C. is a temperature 2.5° C. lower than a temperature Tp° C. (340≤Tp≤345) at which a minimum point is given on a heat-of-fusion curve obtained by measuring an unbaked polymer for measurement having no history of heating to a temperature of 300° C. or higher using a differential scanning calorimeter at a temperature-increasing rate of 2° C./min, and S1 represents an endotherm mJ/mg in a range of 320° C. or higher and T0° C. or lower.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.