Ptfe layers and methods of manufacturing

Patent metadata

Field	Value
Publication number	US-2016367354-A1
Application number	US-201615251011-A
Country	US
Kind code	A1
Filing date	Aug 30, 2016
Priority date	Apr 13, 2005
Publication date	Dec 22, 2016
Grant date	—

Abstract

Thin PTFE layers are described having little or no node and fibril microstructure and methods of manufacturing PTFE layers are disclosed that allow for controllable permeability and porosity of the layers. In some embodiments, the PTFE layers may act as a barrier layer in an endovascular graft or other medical device.

First claim

1 .- 58 . (canceled)

59 . A film comprising:
a material comprising polytetrafluoroethylene; a closed cell microstructure with a plurality of interconnected high density regions of polytetrafluoroethylene having no distinct fibrils interconnecting adjacent nodes when viewed at a magnification of 20,000 under a scanning electron microscope; a thickness from 0.00005 inch to 0.005 inch; and a fluid permeability of substantially no fluid permeability with a Gurley Number of greater than 12 hours for 100 cc of air at a pressure of 12.4 cm of water or of a limited fluid permeability with a Gurley Number of greater than 1,500 seconds for 100 cc of air at a pressure of 12.4 cm of water.

60 . The film of claim 59 , wherein the material further comprises a copolymer of polytetrafluoroethylene.

61 . The film of claim 60 , wherein the copolymer of polytetrafluoroethylene is a fluorinated copolymer of polytetrafluoroethylene.

62 . The film of claim 60 , wherein the copolymer of polytetrafluoroethylene is perfluoropropylvinylether-modified polytetrafluoroethylene.

63 . The film of claim 60 , wherein the copolymer of polytetrafluoroethylene is about 2% or less of the mass of the material.

64 . A vascular graft comprising the film of claim 59 .

65 . A vascular graft comprising:
a body portion having an inflatable channel that defines an inflatable space, wherein the inflatable space is at least partially surrounded by a graft layer; wherein the graft layer comprises:
a material comprising polytetrafluoroethylene;
a closed cell microstructure with a plurality of interconnected high density regions of polytetrafluoroethylene having no distinct fibrils interconnecting adjacent nodes when viewed at a magnification of 20,000 under a scanning electron microscope;
a thickness from 0.00005 inch to 0.005 inch; and
a fluid permeability of substantially no fluid permeability with a Gurley Number of greater than 12 hours for 100 cc of air at a pressure of 12.4 cm of water.

66 . The vascular graft of claim 65 , wherein the material further comprises a copolymer of polytetrafluoroethylene.

67 . The vascular graft of claim 66 , wherein the copolymer of polytetrafluoroethylene is a fluorinated copolymer of polytetrafluoroethylene.

68 . The vascular graft of claim 66 , wherein the copolymer of polytetrafluoroethylene is perfluoropropylvinylether-modified polytetrafluoroethylene.

69 . The vascular graft of claim 66 , wherein the copolymer of polytetrafluoroethylene is about 2% or less of the mass of the material.

70 . A composite film comprising:
a first layer comprising:
a material comprising polytetrafluoroethylene;
a closed cell microstructure with a plurality of interconnected high density regions of polytetrafluoroethylene having no distinct fibrils interconnecting adjacent nodes when viewed at a magnification of 20,000 under a scanning electron microscope;
a thickness from 0.00005 inch to 0.005 inch; and
a fluid permeability of substantially no fluid permeability with a Gurley Number of greater than 12 hours for 100 cc of air at a pressure of 12.4 cm of water or of a limited fluid permeability with a Gurley Number of greater than 1,500 seconds for 100 cc of air at a pressure of 12.4 cm of water;
a second layer of expanded polytetrafluoroethylene having a substantial node and fibril microstructure secured to the first layer.

71 . The composite film of claim 70 , wherein the material further comprises a copolymer of polytetrafluoroethylene.

72 . The composite film of claim 71 , wherein the copolymer of polytetrafluoroethylene is a fluorinated copolymer of polytetrafluoroethylene.

73 . The composite film of claim 71 , wherein the copolymer of polytetrafluoroethylene is perfluoropropylvinylether-modified polytetrafluoroethylene.

74 . The composite film of claim 71 , wherein the copolymer of polytetrafluoroethylene is about 2% or less of the mass of the material.

75 . A vascular graft comprising a thin polytetrafluoroethylene made by a method of processing polytetrafluoroethylene, comprising:
extruding a compounded polytetrafluoroethylene resin through an extruder in a machine direction to form a polytetrafluoroethylene ribbon extrudate; calendering the polytetrafluoroethylene ribbon extrudate in the machine direction to form a layer of polytetrafluoroethylene having an upper surface, a lower surface and a longitudinal length in a machine direction of an extruder used to produce the layer of polytetrafluoroethylene and having a width in a cross machine or transverse direction; applying a liquid stretching agent in an excess amount to at least a portion of the upper surface or the lower surface of the layer of polytetrafluoroethylene; stretching the layer of polytetrafluoroethylene in the transverse direction to the machine direction; and maintaining the excess amount of the liquid stretching agent on the at least portion of the upper or the lower surface of the layer of polytetrafluoroethylene during at least part of the stretching to fully saturate the layer of polytetrafluoroethylene throughout its thickness with the liquid stretching agent during the stretching to form a stretched layer of polytetrafluoroethylene that has: (i) a closed cell microstructure with a plurality of interconnected high density regions of polytetrafluoroethylene having no distinct fibrils interconnecting adjacent nodes when viewed at a magnification of 20,000 under a scanning electron microscope; and (ii) a thickness from 0.00005 inch to 0.005 inch; wherein the stretching is at a rate from 10 percent per second to 100 percent per second; wherein the stretching is performed at a stretch ratio from 2:1 to 20:1; and wherein stretching of the layer of PTFE is performed at a temperature of 80° F. to 100° F.

76 . The vascular graft of claim 76 , wherein the stretched layer of PTFE, after sintering at a temperature from about 350° C. to about 380° C. for about 2 minutes to about 5 minutes, has substantially no fluid permeability with a Gurley Number of greater than 12 hours for 100 cc of air at a pressure of 12.4 cm of water.

77 . The vascular graft of claim 76 , wherein the stretched layer of PTFE has a limited fluid permeability with a Gurley Number of greater than 1,500 seconds for 100 cc of air at a pressure of 12.4 cm of water.

78 . The vascular graft of claim 76 , wherein the compounded PTFE resin comprises polytetrafluoroethylene and a copolymer of polytetrafluoroethylene.

79 . The vascular graft of claim 78 , wherein the copolymer of polytetrafluoroethylene is about 2% or less of the mass of the compounded PTFE resin.

80 . The vascular graft of claim 78 , wherein the copolymer of polytetrafluoroethylene is a fluorinated copolymer of polytetrafluoroethylene.

81 . The vascular graft of claim 78 , wherein the copolymer of polytetrafluoroethylene is perfluoropropylvinylether-modified PTFE.

Assignees

• Trivascular Inc

Inventors

• Humphrey Joseph W
• Skiba Jeffrey B

Classifications

• B29C48/0011

  combined with compression moulding · CPC title

• A61F2250/0003

  having an inflatable pocket filled with fluid, e.g. liquid or gas · CPC title

• A61F2220/005

  using adhesives · CPC title

• B29C48/022

  characterised by the choice of material · CPC title

• B29L2031/7532

  Artificial members, protheses · CPC title