Aqueous polytetrafluoroethylene dispersion composition and process for its production
US7141620B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 20, 2004 |
| Grant date | Nov 28, 2006 |
| Priority date | — |
| Expiry date | Oct 23, 2024 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L71/02
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
To an aqueous PTFE polymer emulsion having a PTFE content of from 10 to 50 mass % obtained by emulsion polymerization of tetrafluoroethylene in the presence of an anionic perfluorocarboxylate surfactant (APFC), from 2 to 20 mass %, based on the mass of PTFE, of a nonionic surfactant having an average molecular weight of from 450 to 800 and an inorganic/organic property ratio of from 1.07 to 1.50 and from 10 to 800 mass %, based on the mass of PTFE, of water are added to obtain an aqueous PTFE dispersion having a PTFE content of from 1 to 40 mass % of PTFE, and then PTFE is concentrated by sedimenting the PTFE and separating a PTFE-rich aqueous dispersion composition from the supernatant. According to the present invention, a PTFE-rich aqueous dispersion composition having a low APFC concentration can be obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.