Patent EP0106496A2 successfully refreshed from Google Patents.
EP0106496A2
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Porous PTFE material
Assignee: W.L. Gore and Associates Inc
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Filing: 1983-09-07
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Granted: —
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Expires: 2003-09-07
Abstract
Abstract Porous PTFE materials having high strength and coarse microstructure are produced by densifying the materials after removal of lubricant and then stretching. The term, "coarse", is used to indicate that the nodes are larger, the fibrils are longer, and the effective pore size is larger than conventional materials of the same matrix tensile strength. Densification can be achieved through the use of such devices as a densification die, a calender machine or a press. This invention can be used to produce all kinds of shaped articles.
Inventors
- 👤 Jeffery Bruce Bowman
- 👤 Daniel Elliott Hubis
- 👤 James David Lewis
- 👤 Stephen Craig Newman
- 👤 Richard Alan Staley
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 21:51
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B29; B29C; B29C55/00; B29C55/005; D; D01; D01F; D01F6/00; D01F6/02; D01F6/08; D01F6/12; B29K; B29K2027/00; B29K2027/12; B29K2027/18; B29K2105/00; B29K2105/04; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
55 words
A porous material consisting essentially of PTFE polymer, which material has a microstructure characterized by nodes interconnected by fibrils characterized in that, as measured along at least one direction, it has a combination of average matrix tensile strength greater than about 15,000 psi (103.5 MPa) and an average node height/width ratio greater than about 3.
Claim 2
Dependent Claim
55 words
A porous material consisting essentially of PTFE polymer, which material has a microstructure characterized by nodes interconnected by fibrils characterized in that, as measured along at least one direction, it has a combination of average matrix tensile strength greater than about 15,000 psi (103.5 MPa) and an average node height/width ratio greater than about 3.
Claim 3
Dependent Claim
23 words
A porous material according to claim 1 characterized in that said average matrix tensile strength is greater than about 40,000 psi (276 MPa):
Claim 4
Dependent Claim
20 words
A porous material according to claim 1 characterized in that said average node height/width ratio is greater than about 5.
Claim 5
Dependent Claim
20 words
A porous material according to claim 2, characterized in that said average node height/width ratio is greater than about 5.
Claim 6
Dependent Claim
21 words
A porous material according to any preceding claim characterized in that it has average fibril length greater than about 15 microns.
Claim 7
Dependent Claim
21 words
A porous material according to any preceding claim characterized in that it has average fibril length greater than about 50 microns.
Claim 8
Dependent Claim
38 words
A porous material according to claim 1 characterized in that said average matrix tensile strength is about 49,000 psi (338 MPa), said average fibril length is about 120 microns, and said average node height-width ratio is about 6.
Claim 9
Dependent Claim
38 words
A porous material according to claim 1 characterized in that said average matrix tensile strength is about 55,000 psi (380 MPa), said average fibril length is about 74 microns, and said average node height/width ratio is about 7.
Claim 10
Dependent Claim
23 words
A porous matrerial according to any one of claims 1 to 4, 7 and 8 characterized in that it is in filament form.
Claim 11
Dependent Claim
81 words
A porous material consisting essentially of polytetraflouroethylene polymer, which material is charaterized by nodes interconnected by fibrils, characterized in that said material has a matrix tensile strength greater than or equal to about 3,000 psi (20.7 MPa).and less than or equal to about 25,000 psi (172.5 MPa) and which has a corresponding coarseness index greater than or equal to the value on a line connecting the points A, B, C, and D in Figure 3 and defined in the following table:
Claim 12
Dependent Claim
81 words
A porous material consisting essentially of polytetraflouroethylene polymer, which material is charaterized by nodes interconnected by fibrils, characterized in that said material has a matrix tensile strength greater than or equal to about 3,000 psi (20.7 MPa).and less than or equal to about 25,000 psi (172.5 MPa) and which has a corresponding coarseness index greater than or equal to the value on a line connecting the points A, B, C, and D in Figure 3 and defined in the following table:
Claim 13
Dependent Claim
21 words
A porous material according to claim 10 characterized in that point C and point D have a coarseness index of 0.23.
Claim 14
Dependent Claim
21 words
A porous material according to claim 10 characterized in that point C and point D have a coarseness index of 0.40.
Claim 15
Dependent Claim
22 words
A porous material according to claim 10 characterized in that points A, B, C, and D have a coarseness index of 0.45.
Claim 16
Dependent Claim
22 words
A porous material according to any one of claims 10 to 12 and 13 characterized in that it is in film form.
Claim 17
Dependent Claim
18 words
A porous material according to claim 14, characterized in that it has a crushability less than about 10%.
Claim 18
Dependent Claim
18 words
A porous material according to claim 14, characterized in that it has a crushability less than about 8%.
Claim 19
Dependent Claim
18 words
A porous material according to claim 14, characterized in that it has a crushability less than about 5%.
Claim 20
Dependent Claim
99 words
A porous material consisting essentially of polytetrafluorethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils characterized in that it has an ethanol bubble point of less than or equal to about 4.0, said fibrils include first fibrils oriented substantially perpendicular to second fibrils, and the ratio of the matrix tensile strength as measured along the first fibril direction to the matrix tensile strength measure along the second fibril direction is between about 0.4 and 2.5, and the matrix tensile strength in the weaker direction is greater than or equal to about 3000 psi (20.7 MPa).
Claim 21
Dependent Claim
99 words
A porous material consisting essentially of polytetrafluorethylene polymer, which material has a microstructure characterized by nodes interconnected by fibrils characterized in that it has an ethanol bubble point of less than or equal to about 4.0, said fibrils include first fibrils oriented substantially perpendicular to second fibrils, and the ratio of the matrix tensile strength as measured along the first fibril direction to the matrix tensile strength measure along the second fibril direction is between about 0.4 and 2.5, and the matrix tensile strength in the weaker direction is greater than or equal to about 3000 psi (20.7 MPa).
Claim 22
Dependent Claim
19 words
A porous material according to claim 18, characterized in that the ethanol bubble point is less than about 3.0.
Claim 23
Dependent Claim
17 words
A porous material according to claim 18 characterized in that the ethanol bubble point is about 1.2.
Claim 24
Dependent Claim
26 words
A porous material according to claim 18, claim 19 or claim 20 characterized in that the matrix tensile strength ratio is between about 0.5 and 2.0.
Claim 25
Dependent Claim
26 words
A porous material according to any one of claims 15, 16 and 17 characterized in that the matrix tensile strength is between about 0.67 and 1.5.
Claim 26
Dependent Claim
37 words
A porous material according to any one of claims 10 to 13, 18, 19 and 20 characterized in that it is in film form and that a significant number of the nodes extend across the film thickness.
Claim 27
Dependent Claim
81 words
A process for producing a porous material of polytetrafluoroethylene polymer, which material is characterized by relatively large nodes interconnected by relatively long fibrils and having relatively high matrix tensile strength, the material having been produced from paste-extruded polytetrafluoroethylene extrudate from which all extrusion-aid lubricant has been removed, characterised in that the process comprises the steps: (a) substantially increasing the density of the dry extrudate; and (b) stretching said densified dry extrudate at an elevated temperature less than the crystalline melt temperature.
Claim 28
Dependent Claim
81 words
A process for producing a porous material of polytetrafluoroethylene polymer, which material is characterized by relatively large nodes interconnected by relatively long fibrils and having relatively high matrix tensile strength, the material having been produced from paste-extruded polytetrafluoroethylene extrudate from which all extrusion-aid lubricant has been removed, characterised in that the process comprises the steps: (a) substantially increasing the density of the dry extrudate; and (b) stretching said densified dry extrudate at an elevated temperature less than the crystalline melt temperature.
Claim 29
Dependent Claim
23 words
A process according to claim 24 characterized in that said densification step increases the dry extrudate density to greater than about 2.0 gm/cc.
Claim 30
Dependent Claim
23 words
A process accordingh to claim 24, characterized in that said densification step increases the dry extruded density to greater than about 2.2 gm/cc.
Claim 31
Dependent Claim
22 words
A process according to claim 24 characterized in that said classification step increases the dry extrudate density to about its maximum value.
Claim 32
Dependent Claim
22 words
A process according to claim 24 characterized in that the densification step is accomplish by densifying the dry extrudate in a press.
Claim 33
Dependent Claim
19 words
A process according to claim 24 characterized in that the densification step is accomplished by calendering the dry extrudate.
Claim 34
Dependent Claim
23 words
A process according to claim 24 characterized in that the densification step is accomplished by drawing the dry extrudate through a densification die.
Claim 35
Dependent Claim
23 words
A process according to any one of claims 24, 28, 29 and 30 characterized in that the densified dry extrudate is stretched uniaxially.
Claim 36
Dependent Claim
22 words
A process according to any one of claims 24, 28 and 29 characterized in that the densified dry extrudate is stretched biaxially.
Claim 37
Dependent Claim
20 words
A process according to claim 24 characterized in that the stretching step is carried out at about 300 9 C.
Claim 38
Dependent Claim
25 words
A process according to claim 24 characterized in that the densification step is carried out at an elevated temperature less than the crystalline melt temperature.
Claim 39
Dependent Claim
19 words
A process according to claim 34 characterized in that the densification step is carried out at about 3000 C.
Claim 40
Dependent Claim
30 words
A process according to claim 24 characterized in that it includes the step of heating the stretched article above the crystalline melt temperature while restraining the stretched article from shrinking.
Claim 41
Dependent Claim
21 words
A process according to claims 24, 29 or 30 characterized in that the densification and stretching steps are carried out continuously.
Claim 42
Dependent Claim
24 words
A process according to any one of claims 24 to 27 characterized by the step of stretching said dry extrudate before said densification step.
References Cited (Backward Citations)
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