Polytetrafluoroethylene aqueous emulsion and process for its production, polytetrafluoroethylene aqueous dispersion obtainable by using such an aqueous emulsion, polytetrafluoroethylene fine powder, and stretched porous material
US9376520B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 2012 |
| Grant date | Jun 28, 2016 |
| Priority date | — |
| Expiry date | Apr 16, 2032 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2327/18
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
To produce a PTFE aqueous emulsion, whereby the environmental load is little, the stability of the aqueous emulsion is high, and a molded product having high heat resistance can be obtained. A process for producing a PTFE aqueous emulsion, which comprises emulsion-polymerizing tetrafluoroethylene (TFE) by means of at least one fluorinated emulsifier selected from the group consisting of a C4-8 fluorinated carboxylic acid having from 1 to 4 etheric oxygen atoms in its main chain, and its salts, to obtain an aqueous emulsion containing polytetrafluoroethylene (PTFE) microparticles having an average primary particle size of from 0.1 to 0.3 μm, wherein at the beginning of the emulsion polymerization of TFE, a (polyfluoroalkyl)ethylene (a) represented by “CH2═CH—Rf1”, and/or a comonomer (b) having a monomer reactivity ratio rTFE of from 0.1 to 8 in copolymerization with tetrafluoroethylene, is incorporated to the emulsion polymerization system, so as to be from 0.001 to 0.01 mass % relative to the final amount of polytetrafluoroethylene produced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.