Fine powders of polytetrafluoroethylene
US6479591B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 19, 2001 |
| Grant date | Nov 12, 2002 |
| Priority date | — |
| Expiry date | Jul 19, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F259/08
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Fine powders of modified PTFE having a “core-shell” structure; the fine powder being formed by:a “core” of tetrafluoroethylene (TFE) modified by one or more monomers selected from:a) dioxoles;b) one or more perfluorinated monomers which cyclize during the polymerization;a “shell” of TFE modified by perfluoropropene (PFP); the amount, referred to the total core+shell particle, of comonomers 1) in the “core” being in the range 0.01-0.06% by weight; the amount, referred to the total core+shell particle, of perfluoropropene 2) in the “shell” being in the range 0.002-0.06% by weight;the thermal instability index (TII) of the fine powder being equal to or lower than 5, determined according to ASTM D4895.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.