# US 10,864,070 B2 · PTFE layers and methods of manufacturing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,864,070 B2 - Document ID: US10864070B2 - Status: Granted - Kind: B2 - Application number: 15/251,011 - Filed: 2016-08-30 - Published: 2016-12-22 - Granted: 2020-12-15 - Earliest claimed: 2005-04-13 - Assignees: TriVascular, Inc. - Applicants: TriVascular, Inc. - Inventors: Joseph W. Humphrey; Jeffrey B. Skiba - Web page: https://patentgrep.com/patent/US10864070B2 ## CPC - A61F 2/07: Stent-grafts - A61L 27/16: obtained by reactions only involving carbon-to-carbon unsaturated bonds - A61L 27/56: Porous materials, {e.g. foams or sponges} - B29C 43/24: Calendering - B29C 48/0011: {combined with compression moulding} - B29C 48/0018: {combined with shaping by orienting, stretching or shrinking, e.g. film blowing (B29C48/0017 takes precedence)} - B29C 48/022: {characterised by the choice of material} - B29C 48/08: flexible, e.g. films - B29C 48/94: Lubricating - B29C 55/005: {characterised by the choice of materials} - B29C 55/02: of plates or sheets - B29C 55/08: transverse to the direction of feed - A61F 2/89: the wire-like elements comprising two or more adjacent rings flexibly connected by separate members - A61F 2002/065: {Y-shaped blood vessels} - A61F 2002/075: {the stent being loosely attached to the graft material, e.g. by stitching} - A61F 2220/005: using adhesives - A61F 2250/0003: having an inflatable pocket filled with fluid, e.g. liquid or gas - B29C 48/95: by adding lubricant to the moulding material - B29K 2027/18: PTFE, i.e. polytetrafluoroethylene {, e.g. ePTFE, i.e. expanded polytetrafluoroethylene} - B29L 2031/7532: {Artificial members, protheses} - Y10T 428/1352: Polymer or resin containing [i.e., natural or synthetic] - Y10T 428/1376: Foam or porous material containing - Y10T 428/139: Open-ended, self-supporting conduit, cylinder, or tube-type article - Y10T 428/1393: Multilayer [continuous layer] - Y10T 428/249981: Plural void-containing components - Y10T 428/3154: Of fluorinated addition polymer from unsaturated monomers - A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C) - A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K) - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## 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. ## Claims ### Claim 1 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, the first layer and the second layer defining an inflatable space therebetween. ### Claim 2 (depends on 1) The composite film of claim 1, wherein the material further comprises a copolymer of polytetrafluoroethylene. ### Claim 3 (depends on 2) The composite film of claim 2, wherein the copolymer of polytetrafluoroethylene is a fluorinated copolymer of polytetrafluoroethylene. ### Claim 4 (depends on 2) The composite film of claim 2, wherein the copolymer of polytetrafluoroethylene is perfluoropropylvinylether-modified polytetrafluoroethylene. ### Claim 5 (depends on 2) The composite film of claim 2, wherein the copolymer of polytetrafluroethylene is about 2% or less of the mass of the material. ### Claim 6 A vascular graft comprising: a composite film having a first layer and a second layer, the 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; and the second layer comprising: a material comprising expanded polytetrafluoroethylene; and a substantial node and fibril microstructure; wherein the second layer is secured to the first layer, and an inflatable space is defined by the space therebetween. ### Claim 7 (depends on 6) The device of claim 6, wherein the first layer comprises a thickness from 0.00005 inch to 0.005 inch. ### Claim 8 (depends on 7) The device of claim 7, wherein the first layer has a limited or substantially no fluid permeability. ### Claim 9 (depends on 8) The device of claim 8, wherein the first layer has a Gurley Number of greater than 12 hours for 100 cc of air at a pressure of 12.4 cm of water. ### Claim 10 (depends on 8) The device of claim 8, wherein the first layer has a Gurley Number of greater than 1,500 seconds for 100 cc of air at a pressure of 12.4 cm of water. ### Claim 11 (depends on 6) The vascular graft of claim 6, wherein the material further comprises a copolymer of polytetrafluoroethylene. ### Claim 12 (depends on 11) The vascular graft of claim 11, wherein the copolymer of polytetrafluoroethylene is a fluorinated copolymer of polytetrafluoroethylene. ### Claim 13 (depends on 12) The vascular graft of claim 12, wherein the copolymer of polytetrafluoroethylene is perfluoropropylvinylether-modified polytetrafluoroethylene. ### Claim 14 (depends on 11) The vascular graft of claim 11, wherein the copolymer of polytetrafluoroethylene is about 2% or less of the mass of the material. ### Claim 15 A vascular graft comprising a thin polytetrafluoroethylene made by a method of processing polytetrafluoroethylene, the method comprising: extruding a compounded PTFE resin through an extruder in a machine direction to form a PTFE ribbon extrudate; calendering the PTFE ribbon extrudate in the machine direction to form a layer of PTFE having an upper surface, a lower surface and a longitudinal length in a machine direction of an extruder used to produce the layer of PTFE 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 PTFE; stretching the layer of PTFE 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 PTFE during at least part of the stretching to fully saturate the layer of PTFE throughout its thickness with the liquid stretching agent during the stretching to form a stretched layer of PTFE that has: (i) a closed cell microstructure with a plurality of interconnected high density regions of PTFE 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; (iii) wherein the stretching is at a rate from 10 percent per second to 100 percent per second; (iv) wherein the stretching is performed at a stretch ratio from 2:1 to 20:1; and (v) wherein stretching of the layer of PTFE is performed at a temperature of 80° F. to 100° F.