Asymmetric polytetrafluoroethylene composite having a macro-textured surface and method for making the same

Patent metadata

Field	Value
Publication number	US-10987638-B2
Application number	US-201615183897-A
Country	US
Kind code	B2
Filing date	Jun 16, 2016
Priority date	Jun 19, 2015
Publication date	Apr 27, 2021
Grant date	Apr 27, 2021

Abstract

Polytetrafluoroethylene (PTFE) composite articles that have a macro textured surface. The composite articles include at least two different PTFE membranes in a layered or stacked configuration. The composite article has a macro textured surface characterized by a plurality of strands raised from the surface of the PTFE membrane. The strands may be formed of either interconnected nodes of PTFE or of at least one nodal mass of PTFE and have a length equal to or greater than about 1.5 mm. The macro textured surface provides a topography to the first PTFE membrane. The composite articles have a bubble point from about 3.0 psi to about 200 psi, a thickness from about 0.01 to about 3.0 mm, and a bulk density from about 0.01 g/cm3 to about 1.0 g/cm3.

First claim

What is claimed is:

1. A composite article comprising:
a first polytetrafluoroethylene (PTFE) membrane having a first surface and a second surface; and
a second PTFE membrane positioned on said second surface of said first membrane,
wherein said first PTFE membrane comprises a plurality of nodes interconnected by fibrils, each said node being formed of a solid mass of PTFE that is raised from the first surface, and
wherein each said solid mass of PTFE has a length greater than or equal to 1.5 mm when measured at any two points taken along the node when viewed with the naked eye.

2. The composite article of claim 1 , wherein said second PTFE membrane has a matrix tensile strength that is greater than a matrix tensile strength of the first PTFE membrane.

3. The composite article of claim 2 , wherein said matrix tensile strength of said second PTFE membrane is at least 1.5 times greater than said matrix tensile strength of said first PTFE membrane in both the x- and the y-directions.

4. The composite article of claim 1 , wherein each said solid mass of PTFE is non-linear and forms a visible pattern on said first surface of said first PTFE membrane.

5. The composite article of claim 1 , wherein said composite article has a bulk density from about 0.01 g/cm 3 to about 1.0 g/cm 3 .

6. The composite article of claim 1 , wherein said composite article has a bubble point from about 3 psi to about 200 psi.

7. The composite article of claim 1 wherein said composite article has a thickness from about 0.01 mm to about 3.0 mm.

8. The composite article of claim 1 , further comprising an adhesive to adhere said first PTFE membrane and said second PTFE membrane.

9. The composite article of claim 8 , wherein said adhesive is a discontinuous or continuous layer of a thermoplastic resin.

10. The composite article of claim 9 wherein said thermoplastic resin is selected from fluorinated ethylene propylene (FEP), perfluoroalkoxy polymer resin (PFA), and tetrafluoroethylene hexafluoropropylene and vinylidene fluoride (THV), polyvinylidene fluoride (PVDF) and combinations thereof.

11. The composite article of claim 1 , wherein at least one of said solid mass of PTFE strands has a length equal to or greater than about 2.0 mm.

12. A composite article comprising:
a first polytetrafluoroethylene (PTFE) membrane having a first surface and a second surface; and
a second PTFE membrane positioned on said second surface of said first membrane,
wherein said first surface of said first PTFE membrane includes a plurality of strands raised from said first surface, each said strand being formed of a solid mass of PTFE having a length of at least 1.5 mm when measured at any two points taken along the solid nodal mass of PTFE when viewed with the naked eye.

13. The composite article of claim 12 , wherein said composite article has a bubble point from about 3 psi to about 200 psi.

14. The composite article of claim 12 , wherein said composite article has a thickness from about 0.01 mm to about 3.0 mm.

15. The composite article of claim 12 , further comprising a discontinuous or continuous layer of a thermoplastic resin between said first PTFE membrane and said second PTFE membrane.

16. The composite article of claim 15 , wherein said thermoplastic resin is selected from fluorinated ethylene propylene (FEP), perfluoroalkoxy polymer resin (PFA), and tetrafluoroethylene hexafluoropropylene and vinylidene fluoride (THV), polyvinylidene fluoride (PVDF) and combinations thereof.

Assignees

• Gore & Ass
• Gore W L & Ass Gmbh

Inventors

• Hollenbaugh Jr Donald L
• Heller Bernadette
• Balaji Gopalan V
• Buxbaum Rebecca

Classifications

• B01D69/1218

  Layers having the same chemical composition, but different properties, e.g. pore size, molecular weight or porosity · CPC title

• B32B7/022

  Mechanical properties · CPC title

• B01D2325/06

  Surface irregularities · CPC title

• B01D67/0027

  by stretching · CPC title

• B32B5/30

  one layer {being formed of particles, e.g. chips,} granules, powder · CPC title