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US 7,306,729 B2Granted
Porous PTFE materials and articles produced therefrom
AssigneeGore Enterprise Holdings, Inc.
InventorsJohn E. Bacino, Alex R. Hobson, Jason J. Strid
Life of this patent
Estimating the term…
Abstract
Novel porous PTFE membranes are described possessing a unique combination of high strength, low flow resistance, and small pore size. Additionally, unique constructions with superior filtration and venting properties incorporating porous PTFE membranes are described.
Claims96
An article comprising
- a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said porous PTFE membrane having a Gurley versus bubble point equal to or below the line defined by the equation log (Gurley)=5.13×10−3 (Bubble Point)−1.26 and a surface area of at least 20 m2/g.
3 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said porous PTFE membrane having a light transmission of at least 50% and a porosity of at least 50%.
2 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said porous PTFE membrane having a bubble point of at least 448 kPa and a Gurley versus bubble point equal to or below the line defined by the equation log (Gurley)=2.60×10−3 (Bubble Point)−0.54.
2 more elements
A porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said porous PTFE membrane having a product of matrix tensile strengths in two orthogonal directions of at least 1.3×105 MPa2.
2 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said porous PTFE membrane having a Gurley versus bubble point equal to or below the line defined by the equation log (Gurley)=5.13×10−3 (Bubble Point)−1.26 and a product of matrix tensile strengths in two orthogonal directions of at least 1.3×105 MPa2.
2 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said porous PTFE membrane having a water entry pressure versus Gurley number equal to or above the line defined by the equation WEP=3(Gurley)+2500.
2 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said porous PTFE membrane having a water flux rate versus bubble point equal to or above the line defined by the equation log (Water Flux Rate)=−3.5×10−3 (Bubble Point)+1.3.
2 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said porous PTFE membrane having a water flux rate versus mean flow pore size equal to or above the line defined by the equation log (water flux rate)=16.9 (mean flow pore size)−1.85.
2 more elements
An article comprising a composite of at least one porous PTFE membrane and at least one additional layer, said porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said composite having a water flux rate versus bubble point equal to or above the line defined by the equation log (Water Flux Rate)=−3.5×10−3 (Bubble Point)+1.3.
2 more elements
An article comprising a composite of at least one porous PTFE membrane and at least one additional layer, said porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said composite further being instantly wettable with water, said composite having a water flux rate versus bubble point equal to or greater than the line defined by the equation log (Water Flux Rate)=−0.01 (Bubble Point)+1.3.
2 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said porous PTFE membrane being instantly wettable with water, said membrane having a water flux rate versus bubble point equal to or above the line defined by the equation log (Water Flux Rate)=−0.01 (Bubble Point)+1.3.
2 more elements
An article comprising at least one porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said porous PTFE membrane having an oleophobic treatment thereon and an oil rating of at least 2, said article having a water entry pressure above 1250 kPa and a Gurley number of greater than 0 and less than 200 seconds.
2 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said porous PTFE membrane having a Gurley versus bubble point equal to or below the line defined by the equation log (Gurley)=5.13×10−3 (Bubble Point)−1.22 and a light transmission of at least 50%.
2 more elements
A method of filtering a fluid comprising:
- providing a filter comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said porous PTFE membrane having a water flux rate versus bubble point equal to or above the line defined by the equation log (Water Flux Rate)=−3.5×10−3 (Bubble Point)+1.3;
- and
- flowing a fluid containing particle through said filter;
- thereby filtering said particles from said fluid.
6 more elements
A method of filtering a fluid comprising:
- providing a filter comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said porous PTFE membrane having a water flux rate versus mean flow pore size equal to or above the line defined by the equation log (water flux rate)=16.9 (mean flow pore size)−1.85;
- and
- flowing a fluid containing contaminants through said filter;
- thereby filtering said particles from said fluid.
6 more elements
A method of filtering a fluid comprising:
- providing a filter comprising a composite of at least one porous PTFE membrane and at least one additional layer, said porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said composite having a water flux rate versus bubble point equal to or above the line defined by the equation log (Water Flux Rate)=−3.5×10−3 (Bubble Point)+1.3;
- and
- flowing a fluid containing particle through said filter;
- thereby filtering said particles from said fluid.
6 more elements
A method of filtering a fluid comprising:
- providing a filter comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste extrusion process;
- stretching the extruded lubricated tape transversely, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape;
- then transversely expanding the tape at an expansion ratio of 20:1 or greater,
- said porous PTFE membrane instantly wettable with water, said membrane having a water flux rate versus bubble point equal to or above the line defined by the equation log (Water Flux Rate)=−0.01 (Bubble Point)+1.3;
- and
- flowing a fluid containing particle through said filter;
- thereby filtering said particles from said fluid.
6 more elements
An article comprising
- a porous PTFE membrane formed by a method comprising:
- forming an extruded lubricated tape of PTFE polymer by a paste forming process;
- stretching the extruded lubricated tape transversely at a ratio of at least 3:1, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape at a temperature above 327° C.;
- then transversely expanding the tape at a temperature above 327° C.,
- said porous PTFE membrane having a Gurley versus bubble point equal to or below the line defined by the equation log (Gurley)=5.13×10−3 (Bubble Point)−1.26 and a surface area of at least 20 m2/g.
3 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste forming process;
- stretching the extruded lubricated tape transversely at a ratio of at least 3:1, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape at a temperature above 327° C.;
- then transversely expanding the tape at a temperature above 327° C.,
- said porous PTFE membrane having a light transmission of at least 50% and a porosity of at least 50%.
2 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste forming process;
- stretching the extruded lubricated tape transversely at a ratio of at least 3:1, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape at a temperature above 327° C.;
- then transversely expanding the tape at a temperature above 327° C.,
- said porous PTFE membrane having a bubble point of at least 448 kPa and a Gurley versus bubble point equal to or below the line defined by the equation log (Gurley)=2.60×10−3 (Bubble Point)−0.54.
2 more elements
A porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste forming process;
- stretching the extruded lubricated tape transversely at a ratio of at least 3:1, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape at a temperature above 327° C.;
- then transversely expanding the tape at a temperature above 327° C.,
- said porous PTFE membrane having a product of matrix tensile strengths in two orthogonal directions of at least 1.3×105 MPa2.
2 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste forming process;
- stretching the extruded lubricated tape transversely at a ratio of at least 3:1, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape at a temperature above 327° C.;
- then transversely expanding the tape at a temperature above 327° C.,
- said porous PTFE membrane having a Gurley versus bubble point equal to or below the line defined by the equation log (Gurley)=5.13×10−3 (Bubble Point)−1.26 and a product of matrix tensile strengths in two orthogonal directions of at least 1.3×105 MPa2.
2 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste forming process;
- stretching the extruded lubricated tape transversely at a ratio of at least 3:1, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape at a temperature above 327° C.;
- then transversely expanding the tape at a temperature above 327° C.,
- said porous PTFE membrane having a water entry pressure versus Gurley number equal to or above the line defined by the equation WEP=3(Gurley)+2500.
2 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste forming process;
- stretching the extruded lubricated tape transversely at a ratio of at least 3:1, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape at a temperature above 327° C.;
- then transversely expanding the tape at a temperature above 327° C.,
- said porous PTFE membrane having a water flux rate versus bubble point equal to or above the line defined by the equation log (Water Flux Rate)=−3.5×10−3 (Bubble Point)+1.3.
2 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste forming process;
- stretching the extruded lubricated tape transversely at a ratio of at least 3:1, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape at a temperature above 327° C.;
- then transversely expanding the tape at a temperature above 327° C.,
- said porous PTFE membrane having a water flux rate versus mean flow pore size equal to or above the line defined by the equation log (water flux rate)=16.9 (mean flow pore size)−1.85.
2 more elements
An article comprising a composite of at least one porous PTFE membrane and at least one additional layer, said porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste forming process;
- stretching the extruded lubricated tape transversely at a ratio of at least 3:1, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape at a temperature above 327° C.;
- then transversely expanding the tape at a temperature above 327° C.,
- said composite having a water flux rate versus bubble point equal to or above the line defined by the equation log (Water Flux Rate)=−3.5×10−3 (Bubble Point)+1.3.
2 more elements
An article comprising a composite of at least one porous PTFE membrane and at least one additional layer, said porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste forming process;
- stretching the extruded lubricated tape transversely at a ratio of at least 3:1, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape at a temperature above 327° C.;
- then transversely expanding the tape at a temperature above 327° C.,
- said composite further being instantly wettable with water, said composite having a water flux rate versus bubble point equal to or greater than the line defined by the equation log (Water Flux Rate)=−0.01 (Bubble Point)+1.3.
2 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste forming process;
- stretching the extruded lubricated tape transversely at a ratio of at least 3:1, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape at a temperature above 327° C.;
- then transversely expanding the tape at a temperature above 327° C.,
- said porous PTFE membrane being instantly wettable with water, said membrane having a water flux rate versus bubble point equal to or above the line defined by the equation log (Water Flux Rate)=−0.01 (Bubble Point)+1.3.
2 more elements
An article comprising at least one porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste forming process;
- stretching the extruded lubricated tape transversely at a ratio of at least 3:1, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape at a temperature above 327° C.;
- then transversely expanding the tape at a temperature above 327° C.,
- said porous PTFE membrane having an oleophobic treatment thereon and an oil rating of at least 2, said article having a water entry pressure above 1250 kPa and a Gurley number of greater than 0 and less than 200 seconds.
2 more elements
An article comprising a porous PTFE membrane formed by a method comprising
- forming an extruded lubricated tape of PTFE polymer by a paste forming process;
- stretching the extruded lubricated tape transversely at a ratio of at least 3:1, and drying the stretched tape to remove lubricant;
- longitudinally expanding the resulting tape at a temperature above 327° C.;
- then transversely expanding the tape at a temperature above 327° C.,
- said porous PTFE membrane having a Gurley versus bubble point equal to or below the line defined by the equation log (Gurley)=5.13×10−3 (Bubble Point)−1.22 and a light transmission of at least 50%.
2 more elements
Dependencies are inferred from the claim text.