Articles including expanded polytetrafluoroethylene membranes with serpentine fibrils and having a discontinuous fluoropolymer layer thereon

Patent metadata

Field	Value
Publication number	US-9510935-B2
Application number	US-201213675730-A
Country	US
Kind code	B2
Filing date	Nov 13, 2012
Priority date	Jan 16, 2012
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

Articles comprising an expanded polytetrafluoroethylene membrane having serpentine fibrils and having a discontinuous coating of a fluoropolymer thereon are provided. The fluoropolymer may be located at least partially in the pores of the expanded fluoropolymer membrane. In exemplary embodiments, the fluoropolymer is fluorinated ethylene propylene. The application of a tensile force at least partially straightens the serpentine fibrils, thereby elongating the article. The expanded polytetrafluoroethylene membrane may include a microstructure of substantially only fibrils. The articles can be elongated to a predetermined point at which further elongation is inhibited by a dramatic increase in stiffness. In one embodiment, the articles are used to form a covered stent device that requires little force to distend in the radial direction to a first diameter but is highly resistant to further distension to a second diameter (stop point). A large increase in diameter can advantageously be achieved prior to reaching the stop point.

First claim

What is claimed is:

1. An article comprising:
a wrinkle-free expanded polytetrafluoroethylene membrane having a discontinuous coating of a fluoropolymer material thereon,
wherein said expanded polytetrafluoroethylene membrane includes a plurality of serpentine fibrils.

2. The article of claim 1 , wherein the expanded polytetrafluoroethylene membrane comprises pores and the fluoropolymer material at least partially penetrates a plurality of said pores.

3. The article of claim 1 , wherein the fluoropolymer material is fluorinated ethylene propylene.

4. The article of claim 1 , wherein the expanded polytetrafluoroethylene membrane has a microstructure of substantially only said serpentine fibrils.

5. The article of claim 1 , wherein the expanded polytetrafluoroethylene membrane is thermally retracted in at least one direction to less than about 90% of the initial, expanded polytetrafluoroethylene membrane length.

6. The article of claim 5 , wherein the expanded polytetrafluoroethylene membrane is thermally retracted in at least one direction.

7. The article of claim 6 , wherein the expanded polytetrafluoroethylene membrane is restrained in at least one direction during said thermal retraction.

8. The article of claim 1 , further comprising at least one elastomer incorporated at least partially into the expanded polytetrafluoroethylene membrane.

9. The article of claim 1 , wherein said width of said serpentine fibril is 0.5 microns or less.

10. The article of claim 1 , wherein said serpentine fibrils have a width of about 1.0 micron or less.

11. The article of claim 1 , wherein said serpentine fibrils comprise a multiplicity of fibrils having length portions coalesced together.

12. An endoprosthetic device comprising:
a wrinkle-free cover defining at least one opening, an interior surface, and an exterior surface, said wrinkle-free cover comprising a composite material including an expanded polytetrafluoroethylene membrane having a discontinuous coating of another material thereon,
wherein said expanded polytetrafluoroethylene membrane includes a plurality of serpentine fibrils.

13. The endoprosthetic device of claim 12 , wherein said serpentine fibrils have a width of about 1.0 micron or less.

14. The endoprosthetic device of claim 13 , wherein said serpentine fibrils have a width of 0.5 microns or less.

15. The endoprosthetic device of claim 12 , wherein the expanded polytetrafluoroethylene membrane comprises pores and the another material at least partially penetrates a plurality of said pores.

16. The endoprosthetic device of claim 12 , wherein said wrinkle-free cover is a cover for a stent.

17. The endoprosthetic device of claim 16 , wherein said another material on said exterior surface bonds to said another material on said interior surface through interstices of said stent to affix said wrinkle-free cover to said stent.

18. The endoprosthetic device of claim 12 , wherein said another material comprises a member selected from the group consisting of fluorinated ethylene propylene (FEP), ethylene fluorinated ethylene propylene (EFEP), THV (a terpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride), PFA (perfluoroalkoxy copolymer resin), ECTFE (ethylene chlorotrifluoroethylene), PVDF (polyvinylidene fluoride) and PEEK (polyether ether ketone).

19. The endoprosthetic device of claim 12 , wherein said another material is fluorinated ethylene propylene.

20. The endoprosthetic device of claim 12 , wherein the expanded polytetrafluoroethylene membrane possesses a microstructure of substantially only said serpentine fibrils.

21. The endoprosthetic device of claim 12 , wherein said composite material is radially expanded to a diameter beyond which further expansion is inhibited.

22. The endoprosthetic device of claim 12 , further comprising at least one elastomer incorporated at least partially into the expanded polytetrafluoroethylene membrane.

23. The endoprosthetic device of claim 12 , wherein the expanded polytetrafluoroethylene membrane is thermally retracted in at least one direction to less than about 90% of the initial, expanded polytetrafluoroethylene membrane length.

24. The endoprosthetic device of claim 23 , wherein the expanded polytetrafluoroethylene membrane is restrained in at least one direction during said thermal retraction.

25. The endoprosthetic device of claim 12 , wherein said composite material exhibits an increase in stiffness when expanded to a diameter of about 7 mm.

26. The article of claim 12 , wherein said serpentine fibrils comprise a multiplicity of fibrils having length portions coalesced together.

27. A stent graft comprising:
a stent having a wall with at least one opening, an exterior surface, and an interior surface; and
a wrinkle-free cover affixed to said stent,
wherein said cover comprises a composite material including an expanded polytetrafluoroethylene membrane having serpentine fibrils and a discontinuous coating of a fluoropolymer thereon.

28. The stent graft of claim 27 , wherein said composite material at least partially covers at least one of said interior and said exterior surfaces of said stent.

29. The stent graft of claim 27 , wherein said serpentine fibrils have a width of about 1.0 micron or less.

30. The stent graft of claim 27 , where said cover material remains wrinkle-free regardless of the diameter of the stent graft.

31. The stent graft of claim 27 , wherein said composite material is radially expanded to a diameter beyond which further expansion is inhibited.

32. The stent graft of claim 27 , wherein said serpentine fibrils comprise a multiplicity of fibrils having length portions coalesced together.

33. The stent graft of claim 27 , wherein said expanded polytetrafluoroethylene membrane comprises pores and said fluoropolymer at least partially penetrates a plurality of said pores.

34. The article of claim 27 , wherein said fluoropolymer is fluorinated ethylene propylene.

35. The article of claim 27 , further comprising at least one elastomer incorporated at least partially into said expanded polytetrafluoroethylene membrane.

Assignees

• Gore & Ass

Inventors

• Kovach Larry J
• Radspinner Rachel

Classifications

• A61F2002/075

  the stent being loosely attached to the graft material, e.g. by stitching · CPC title

• Y10T428/2481

  including layer of mechanically interengaged strands, strand-portions or strand-like strips · CPC title

• B32B38/1866

  conforming the layers or laminate to a convex or concave profile · CPC title

• Y10T428/24802

  Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.] · CPC title

• A61L31/048 Primary

  obtained by reactions only involving carbon-to-carbon unsaturated bonds (A61L31/041 takes precedence) · CPC title