US4283448A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composite polytetrafluoroethylene article and a process for making the same
Assignee: W.L. Gore and Associates Inc
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Filing: 1980-02-14
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Granted: 1981-08-11
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Expires: 2000-02-14
Abstract
Abstract A porous polytetrafluoroethylene (PTFE) article which is made up of a number of smaller articles with a microstructure of nodes interconnected by fibrils, these articles having been joined to one another such that their microstructure is virtually unaltered across the join. A process for producing such a PTFE article by closely abutting small-shaped PTFE segments and applying a force perpendicular to the seam while heating to a temperature above the crystalline melt point of the segments.
Inventors
- 👤 Jeffery B. Bowman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 16:29
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/12; C08J5/121; A; A61; A61F; A61F2/00; A61F2/02; A61F2/04; A61F2/06; B; B29; B29C; B29C53/00; B29C53/36; B29C53/38; B29C53/385; B29C61/00; B29C61/006; B29C65/00; B29C65/02; B29C65/022; B29C65/82; B29C65/8253; B29C66/00; B29C66/01; B29C66/05; B29C66/10; B29C66/11; B29C66/114; B29C66/1142; B29C66/40; B29C66/41; B29C66/43; B29C66/432; B29C66/49; B29C66/70; B29C66/71; B29C66/73; B29C66/739; B29C66/7392; B29C66/73921; B29C66/80; B29C66/82; B29C66/826; B29C66/8264; B29C66/737; B29C66/7371; B29C66/73711; B29C66/73712; B29C66/7377; B29C66/73773; B29C66/73774; B29K; B29K2027/00; B29K2027/12; B29K2027/18; B29L; B29L2031/00; B29L2031/14; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18; Y; Y10; Y10S; Y10S138/00; Y10S138/03; Y10T; Y10T428/00; Y10T428/13; Y10T428/1328; Y10T428/1331; Y10T428/19; Y10T428/192; Y10T428/31504; Y10T428/3154
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
113 words
A process for joining a plurality of shrinkable expanded porous polytetrafluoroethylene segments, each having a microstructure of nodes interconnected by fibrils, such that the microstructure is virtually uninterrupted at the seam joining said segments, comprising the steps of: (a) arranging said segments such that their edges are disposed in abutting relationship; (b) causing a pressure to be applied perpindicular to said abutting edges; (c) causing said segments to be restrained from shrinking in any direction; (d) heating said segments while they are so held, to a temperature above the crystalline melt point of polytetrafluoroethylene for a predetermined time; and (e) allowing said segments to cool while still being held restrained and under pressure.
Claim 2
Dependent Claim
113 words
A process for joining a plurality of shrinkable expanded porous polytetrafluoroethylene segments, each having a microstructure of nodes interconnected by fibrils, such that the microstructure is virtually uninterrupted at the seam joining said segments, comprising the steps of: (a) arranging said segments such that their edges are disposed in abutting relationship; (b) causing a pressure to be applied perpindicular to said abutting edges; (c) causing said segments to be restrained from shrinking in any direction; (d) heating said segments while they are so held, to a temperature above the crystalline melt point of polytetrafluoroethylene for a predetermined time; and (e) allowing said segments to cool while still being held restrained and under pressure.
Claim 3
Dependent Claim
9 words
A composite article made in accordance with claim 1.
Claim 4
Independent Claim
137 words
A method for manufacturing a porous composite tube from a plurality of segments of shrinkable expanded porous polytetrafluoroethylene, each having a microstructure of nodes interconnected by fibrils such that the microstructure is virtually uninterrupted at the seam joining said segments comprising the steps of: (a) forming a tube of expanded porous polytetrafluoroethylene segments by disposing said segments around a suitable mandrel in abutting relationship; (b) winding a film of high strength shrinkable expanded porous polytetrafluoroethylene with a microstructure of nodes interconnected by fibrils around said segments; (c) restraining said segments from shrinking longitudinally; (d) bonding and shrinking said film to said segment, thereby applying pressure perpindicular to the edge of said segments by heating to a temperature above the crystalline melt point of polytetrafluoroethylene for a predetermined time; and (e) allowing said wrapped bonded segments to cool.
Claim 5
Independent Claim
137 words
A method for manufacturing a porous composite tube from a plurality of segments of shrinkable expanded porous polytetrafluoroethylene, each having a microstructure of nodes interconnected by fibrils such that the microstructure is virtually uninterrupted at the seam joining said segments comprising the steps of: (a) forming a tube of expanded porous polytetrafluoroethylene segments by disposing said segments around a suitable mandrel in abutting relationship; (b) winding a film of high strength shrinkable expanded porous polytetrafluoroethylene with a microstructure of nodes interconnected by fibrils around said segments; (c) restraining said segments from shrinking longitudinally; (d) bonding and shrinking said film to said segment, thereby applying pressure perpindicular to the edge of said segments by heating to a temperature above the crystalline melt point of polytetrafluoroethylene for a predetermined time; and (e) allowing said wrapped bonded segments to cool.
Claim 6
Dependent Claim
9 words
A composite article made in accordance with claim 3.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-10 | 1985-02-09 | 1985-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-10 | 1989-02-09 | 1989-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-10 | 1993-02-09 | 1993-08-11 | $7700.00 | Window Closed / Lapsed |