US5026513A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for making rapidly recoverable PTFE
Assignee: W.L. Gore and Associates Inc
•
Filing: 1989-05-22
•
Granted: 1991-06-25
•
Expires: 2009-05-22
Abstract
Abstract This invention relates to porous polytetrafluoroethylene (hereinafter PTFE) materials having the property of rapid recovery and a method for producing these materials. The microstructure of the porous PTFE material consists of nodes interconnected by fibrils, substantially all of the fibrils having a bent or wavy appearance. Articles made from these materials are particularly suitable for use in the medical field, but are also useful in other areas such as filtration and fabric applications.
Inventors
- 👤 Wayne D. House
- 👤 David J. Myers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:22
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B29; B29C; B29C55/00; B29C55/005; B29C67/00; B29C67/20; B29K; B29K2027/00; B29K2027/12; B29K2027/18; B29K2105/00; B29K2105/04; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18; Y; Y10; Y10S; Y10S264/00; Y10S264/47
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
91 words
A process for making rapid recoverable polytetrafluoroethylene (PTFE) material having a microstructure of nodes and fibrils comprising extruding a preformed billet of a mixture of coagulated dispersion of PTFE and liquid lubricant, expanding said PTFE after removal of liquid lubricant by stretching said PTFE longitudinally and maintaining said PTFE at a temperature between about 35° C. and the crystalline melt point during stretching, compressing said extruded and expanded PTFE in the direction of the fibrils to reduce its size, restraining said PTFE in its compressed state, and heating said compressed PTFE.
Claim 2
Dependent Claim
91 words
A process for making rapid recoverable polytetrafluoroethylene (PTFE) material having a microstructure of nodes and fibrils comprising extruding a preformed billet of a mixture of coagulated dispersion of PTFE and liquid lubricant, expanding said PTFE after removal of liquid lubricant by stretching said PTFE longitudinally and maintaining said PTFE at a temperature between about 35° C. and the crystalline melt point during stretching, compressing said extruded and expanded PTFE in the direction of the fibrils to reduce its size, restraining said PTFE in its compressed state, and heating said compressed PTFE.
Claim 3
Dependent Claim
22 words
A process as claimed in claim 1 wherein said compressed polytetrafluoroethylene is heated to a temperature above about its crystalline melt point.
Claim 4
Dependent Claim
68 words
A process for manufacturing a porous polytetrafluoroethylene tube with a microstructure of nodes and fibrils having rapid recovery in excess of about 5.5% comprising the steps of: a) compressing and restraining said tube to less than about 50% of its original length; b) heating at an elevated temperature for a period of time; c) allowing it to cool; and d) stretching the tube to approximately its original length.
Claim 5
Dependent Claim
68 words
A process for manufacturing a porous polytetrafluoroethylene tube with a microstructure of nodes and fibrils having rapid recovery in excess of about 5.5% comprising the steps of: a) compressing and restraining said tube to less than about 50% of its original length; b) heating at an elevated temperature for a period of time; c) allowing it to cool; and d) stretching the tube to approximately its original length.
Claim 6
Dependent Claim
67 words
A process for manufacturing a porous polytetrafluoroethylene tube with a microstructure of nodes and fibrils having rapid recovery in excess of about 5.5% comprising the steps of: a) compressing and restraining said tube to less than about 50% of its original length; b) maintaining the tube in a compressed and restrained state for a period of time; and c) stretching the tube to approximately its original length.
Claim 7
Dependent Claim
67 words
A process for manufacturing a porous polytetrafluoroethylene tube with a microstructure of nodes and fibrils having rapid recovery in excess of about 5.5% comprising the steps of: a) compressing and restraining said tube to less than about 50% of its original length; b) maintaining the tube in a compressed and restrained state for a period of time; and c) stretching the tube to approximately its original length.
References Cited (Backward Citations)
US3086242A
Cited
US3076233A
Cited
US3225129A
Cited
US3417176A
Cited
GB1273717A
Cited
US3962153A
Cited
US4187390A
Cited
US3717746A
Cited
US3813461A
Cited
GB1357829A
Cited
GB1475316A
Cited
GB1505591A
Cited
US4042747A
Cited
GB1577327A
Cited
JPS5461259A
Cited
JPS54119562A
Cited
GB2037294A
Cited
GB2086305A
Cited
EP0051957A2
Cited
EP0111339A1
Cited
US4550447A
Cited
US4647416A
Cited
JPS60104319A
Cited
GB2197870A
Cited
US4876051A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-24 | 1994-12-24 | 1995-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-24 | 1998-12-24 | 1999-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-24 | 2002-12-24 | 2003-06-25 | $7700.00 | Window Closed / Lapsed |