Polytetrafluoroethylene fine powder and process for producing the same
USRE31341E · kind E · reissue
Assignee
Inventors
Key dates
| Filing date | Jun 25, 1981 |
| Grant date | Aug 9, 1983 |
| Priority date | — |
| Expiry date | Jun 25, 2001 |
Classification
- Technology area (CPC —)General
Abstract
Polytetrafluoroethylene fine powders which have an average molecular weight of not less than 5,000,000, preferably not less than 5,500,000, an amorphous index of not more than 0.1, preferably not more than 0.09, a number average primary particle size of 0.1 to 0.4 micron, preferably 0.15 to 0.38 micron, and a sharp endothermic peak at a temperature between 343.degree. C. and 350.degree. C. on the melting diagram by a differential scanning calorimeter, said sharp peak having an endothermic ratio of not more than 0.3, preferably not more than 0.27, and a half value width of the endothermic peak of not more than 8 degrees, preferably not more than 6 degrees, and a process for producing the polytetrafluoroethylene fine powders. The polytetrafluoroethylene fine powders have an excellent stretchability and are useful for electric wire coating, small diameter tubes, large diameter tubes, sealing tapes and the like.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.