Porous structure of polytetrafluoroethylene and process for production thereof

• US 4,713,070 A
• Filed: 01/24/1986
• Issued: 12/15/1987
• Est. Priority Date: 11/30/1978
• Status: Expired due to Term

• Current Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Original Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Inventors: Mano, Hiroshi
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Cannon, Alan W.
• Application Number:
  US06/821,528
• Time in Patent Office: 690 Days
• Field of Search: 623/1, 623/12, 623/66, 428/376, 128/DIG. 14
• US Class Current: 623/1.39
• CPC Class Codes: A61F 2/04 Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts A61F2/18, A61F2/20 take precedence; devices, other than stent-grafts, providing patency to, or preventing collapsing of, tubular structures of the body other than stent-grafts, e.g. stents A61F2/82; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95
• CPC Class Codes: A61F 2/06 Blood vessels
• 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 29/041 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 29/146 Porous materials, e.g. foams or sponges
• CPC Class Codes: B29C 48/022 characterised by the choice of material
• CPC Class Codes: B29C 48/05 Filamentary, e.g. strands
• 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: C08J 2327/18 Homopolymers or copolymers of tetrafluoroethylene
• CPC Class Codes: C08J 5/18 Manufacture of films or sheets
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: Y10S 128/14 Polytetrafluoroethylene, i.e. PTFE
• CPC Class Codes: Y10T 428/2935 Discontinuous or tubular or cellular core

Abstract

A porous polytetrafluoroethylene material is disclosed having a molecular microfibrous structure having, at one surface, a strong orientation in a given direction and, at another opposite surface, a strong orientation and a direction at right angles to the first, in which the orientation of the microfibrous structure progressively changes from one surface to the other. A process for preparing such an element is also disclosed.

Claims

1. A unitary porous structure of polytetrafluoroethylene having a microfibrous structure composed of fibers and nodes connected to one another by these fibers, said microfibrous structure having at one surface a strong orientation of fiber in one direction and at another surface a strong orientation of nodes sintered by means of heating above 327°

C. resulting in melt-adhesion of the nodes connected to one another in a direction at right angles to the aforesaid direction, the orientation of said microfibrous structure progressively changing from one surface to the other.

2. A porous tubing of polytetrafluoroethylene having a microfibrous structure composed of fibers and nodes connected to one another by these fibers, the average pore diameter of the outside surface of said tubing being larger than that of its inside surface, and said fibrous structure changing progressively within the wall of the tubing from its inside surface in which the fibrous structure has a strong orientation of fibers in the axial direction of the tubing to its outside surface in which the fibrous structure has a strong orientation of nodes sintered by means of heating above 327°

C. resulting in melt-adhesion of the nodes connected to one another around the axis of the tubing.

3. The porous tubing of claim 2, wherein the inside surface of the tubing has an average pore diameter of about 1 to 100 μ

m, and the outside surface has an average pore diameter of about 0.1 to 1.0 mm.

4. A vascular prosthesis which is in the form of a porous tubing of polytetrafluoroethylene having a microfibrous structure composed of fibers and nodes connected to one another by these fibers, the average pore diameter of the outside surface of said tubing being larger than that of its inside surface, and said fibrous structure changing progressively within the wall of the tubing from its inside surface in which the fibrous structure has a strong orientation of fibers in the axial direction of the tubing to its outside surface in which the fibrous structure has a strong orientation of nodes sintered by means of heating above 327°

resulting in melt-adhesion of the nodes connected to one another around the axis of the tubing.

5. A vascular prosthesis according to claim 4, wherein the inside surface of the tubing has an average pore diameter of about 1 to 100 μ

m, and the outside surface has an average pore diameter of about 0.1 to 1.0 mm.

6. The vascular prosthesis according to claim 4, wherein the tubing has an inside diameter of 4.0 mm and an outside diameter of 4.9 mm.

7. The vascular prosthesis according to claim 6, wherein the porous tubing has as average pore diameter of 2.0 μ

m at the inside surface and an average pore diameter of 150 μ

m at the outside surface.

8. The vascular prosthesis according to claim 7, wherein the porous tubing has a porosity of 80%.

9. The vascular prosthesis according to claim 4, wherein the porous tubing has a porosity of 80%.

10. A vascular prosthesis according to claim 6, wherein the inside surface of the tubing has an average pore diameter of about 1 to 100 μ

m, and the outside surface has an average pore diameter of about 0.1 to 1.0 mm.

11. A vascular prosthesis according to claim 9, wherein the inside surface of the tubing has an average pore diameter of about 1 to 100 μ

m, and the outside surface has an average pore diameter of about 0.1 to 1.0 mm.