Expanded PTFE articles and method of making same
View Patent ↗Unique PTFE structures comprising islands of PTFE attached to an underlying expanded polytetrafluoroethylene (ePTFE) structure and to methods of making such structures is disclosed. The ePTFE material may or may not have been exposed to amorphous locking temperatures. These unique structures exhibit islands of PTFE attached to and raised above the expanded PTFE structures.
1. An article comprising:
a first, expanded PTFE material having an outer surface which defines a baseline, and
raised islands comprising PTFE originating from the first, expanded PTFE material and extending above the baseline.
2. The article of claim 1 , wherein said raised islands are of lower molecular weight than the PTFE of the underlying PTFE material from which they extend.
3. The article of claim 1 in the form of a fiber.
4. The article of claim 1 in the form of a membrane.
5. The article of claim 1 , further comprising at least one filler material.
6. The article of claim 5 , wherein the at least one filler is in the expanded PTFE material.
7. The article of claim 5 , wherein the at least one filler is in the raised islands.
8. The article of claim 1 , wherein said raised islands are oriented on the underlying PTFE material in a patterned configuration.
9. The article of claim 1 , wherein said islands do not exhibit a melt temperature upon differential scanning calorimetry at or above 380° C.
10. The article of claim 1 in the form of a sheet.
11. The article of claim 1 in the form of a tube.
12. The article of claim 1 , wherein said article is in the form of a plurality of monofilament fibers combined in a twisted configuration.
13. An article comprising:
a plurality of monofilament fluoropolymer fibers combined in a twisted configuration,
said twisted configuration having a density >1 g/cc and a fiber fray scored <100.