Process for preparing polytetrafluoroethylene fine powders
US4098975A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 1977 |
| Grant date | Jul 4, 1978 |
| Priority date | — |
| Expiry date | Mar 11, 1997 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F14/26
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A process for preparing a polytetrafluoroethylene fine powder by polymerizing tetrafluoroethylene in an aqueous medium containing a polymerization initiator and a dispersant, coagulating the resulting polymer, washing the coagulated polymer when desired, and drying the polymer, characterized in that after at least 30 wt. % of the whole amount of the tetrafluoroethylene to be polymerized has been polymerized at a constant temperature, the polymerization is conducted at an altered temperature at which the same whole amount, when polymerized, gives a polymer having an amorphous index at least 0.01 higher than when the whole amount is polymerized at the first-mentioned temperature.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.