Expanded TFE copolymers, method of making and porous, expanded articles thereof

• US 8,911,844 B2
• Filed: 03/11/2013
• Issued: 12/16/2014
• Est. Priority Date: 10/04/2007
• Status: Active Grant

• Current Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Original Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Inventors: Ford, Lawrence A.
• Primary Examiner(s): Buie-Hatcher, Nicole M
• Application Number:
  US13/792,398
• Publication Number:
  US 20130189464A1
• Time in Patent Office: 645 Days
• Field of Search: 428/36.5, 521/145
• US Class Current: 428/36.5
• CPC Class Codes: A61F 2/06 Blood vessels
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61L 27/16 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/507 for artificial blood vessels apparatus for applying cells on a blood vessel prosthesis A61F2/062
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 31/048 obtained by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: A61L 31/146 Porous materials, e.g. foams or sponges
• CPC Class Codes: B29C 55/005 characterised by the choice of materials
• CPC Class Codes: B29K 2027/18 PTFE, i.e. polytetrafluorethene , e.g. ePTFE, i.e. expanded polytetrafluorethene
• CPC Class Codes: B29K 2105/04 cellular or porous
• CPC Class Codes: C08F 14/26 Tetrafluoroethene
• CPC Class Codes: C08F 2/24 with the aid of emulsifying agents
• CPC Class Codes: C08F 214/26 Tetrafluoroethene
• CPC Class Codes: C08F 214/262 with fluorinated vinyl ethers
• CPC Class Codes: C08F 214/265 with non-fluorinated comonomers
• CPC Class Codes: C08F 259/08 on to polymers containing fluorine
• CPC Class Codes: C08J 2207/02 Adhesive
• CPC Class Codes: C08J 2327/18 Homopolymers or copolymers of tetrafluoroethylene
• CPC Class Codes: C08J 9/00 Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof mechanical aspects of shaping of plastics or substances in a plastic state for the production of porous or cellular articles B29C
• CPC Class Codes: C08J 9/16 Making expandable particles
• CPC Class Codes: C08L 27/18 : Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: Y10T 428/1376 : Foam or porous material containing

Abstract

A true tetrafluoroethylene (TFE) copolymer of the fine powder type is provided, wherein the copolymer contains polymerized comonomer units of at least one comonomer other than TFE in concentrations of at least or exceeding 1.0 weight percent, and which can exceed 5.0 weight percent, wherein the copolymer is expandable, that is, the copolymer may be expanded to produce strong, useful, expanded TFE copolymeric articles having a microstructure of nodes interconnected by fibrils. Articles made from the expandable copolymer may include tapes, membranes, films, fibers, and are suitable in a variety of end applications, including medical devices.

Claims

1. A porous material having a microstructure of nodes interconnected by fibrils comprising an expanded core-shell tetrafluoroethylene (TFE) copolymer, said copolymer comprising:

(a) a first, core portion comprising a polymer chain of TFE monomers and at least one comonomer; and

(b) a second, shell portion consisting of a polymer chain consisting of TFE monomers,

wherein said expandable core-shell tetrafluoroethylene copolymer comprises at least 3.0% by weight polymerized units of said at least one comonomer based on total weight of said copolymer,

wherein said copolymer comprises a first melt transition temperature and a second melt transition temperature, and

wherein said copolymer exhibits adhesion.

2. The porous material of claim 1, wherein said at least one other comonomer is an olefin selected from the group consisting of ethylene, propylene and isobutylene.

3. The porous material of claim 1, wherein said at least one other comonomer is a fluorinated monomer selected from the group consisting of chlorotrifluoroethylene (CTFE), hexafluoro-propylene (HFP), vinylidene fluoride (CFH═

CH₂), vinylidene difluoride (CF₂═

CH₂), hexafluoroisobutylene(HFIB), trifluoroethylene (CF₂═

CFH), a fluorodioxole and a fluorodioxalane.

4. The porous material of claim 1, wherein said at least one other comonomer is a perfluoroalkyl ethylene monomer.

5. The porous material of claim 4, wherein said perfluoroalkyl ethylene monomer is selected from the group consisting of perfluorobutylethylene (PFBE), perfluorohexyl ethylene (PFHE) and perfluorooctylethylene (PFOE).

6. The porous material of claim 1, wherein said at least one other comonomer is a perfluoroalkyl vinyl ether monomer.

7. The porous material of claim 6, wherein said perfluoroalkyl vinyl ether monomer is PMVE.

8. The porous material of claim 6, wherein said perfluoroalkyl vinyl ether monomer is PEVE.

9. The porous material of claim 6, wherein said perfluoroalkyl vinyl ether monomer is PPVE.

10. The porous material of claim 1, including more than one other comonomer.

11. The porous material of claim 1, having at least 5.0% by weight polymerized units of said at least one comonomer.

12. The porous material of claim 1, wherein the expanded core-shell tetrafluoroethylene copolymer is prepared from a fine powder.

13. The porous material of claim 1 in the form of a shaped article.

14. The article of claim 13 in the form of a sheet or film.

15. The article of claim 13 in the form of a tube.

16. The article of claim 13 in the form of a rod.

17. The article of claim 13 in the form of a continuous filament.

18. The shaped article of claim 13 having a matrix tensile strength in at least one direction exceeding 5,000 psi.

19. The shaped article of claim 13 having a matrix tensile strength in at least one direction exceeding 15,000 psi.

20. The shaped article of claim 13 having a matrix tensile strength in at least one direction exceeding 30,000 psi.

21. The article of claim 13 in the form of a medical device.

22. The article of claim 13 in the form of an implantable medical device.

23. The article of claim 13 in the form of a vascular graft.

24. The article of claim 13 in the form of an endoluminal prosthesis.