Patent US6048484A successfully refreshed from Google Patents.
US6048484A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for forming a seamless tube of expanded PTFE from a sheet of expanded PTFE
Assignee: W.L. Gore and Associates Inc
•
Filing: 1996-11-01
•
Granted: 2000-04-11
•
Expires: 2016-11-01
Abstract
Abstract A method of making a seamless, thinwall tube of porous polytetrafluoroethylene. The method involves the use of corresponding male and female dies to deform a precursor sheet of porous PTFE which has been restrained about its perimeter. Preferably the porous PTFE sheet is heated to a temperature of less than the crystalline melt temperature during the tube-forming process. The precursor material is preferably a sheet of porous expanded PTFE and more preferably a multiaxially expanded sheet. This precursor material may optionally have been previously exposed to heat above the melt temperature of PTFE. The inventive tube is as thin or thinner than the precursor sheet.
Inventors
- 👤 Wayne D. House
- 👤 Kenneth W. Moll
- 👤 Stanislaw L. Zukowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:46
CPC Classifications
B; B29; B29D; B29D23/00; B29D23/20; A; A61; A61L; A61L27/00; A61L27/14; A61L27/16; A61L31/00; A61L31/04; A61L31/048; B29C; B29C51/00; B29C51/08; B29C51/082; B29C55/00; B29C55/005; A61F; A61F2/00; A61F2/02; A61F2/04; A61F2/06; A61F2/07; A61F2/82; B29K; B29K2027/00; B29K2027/12; B29K2027/18; B29L; B29L2023/00; B29L2023/20; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1352; Y10T428/139; Y10T428/24; Y10T428/24273; Y10T428/249921; Y10T428/249953; Y10T428/249978; Y10T428/249979; Y10T428/26; Y10T428/268
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
96 words
A method for making a seamless tube of porous expanded polytetrafluoroethylene having a microstructure of nodes interconnected by fibrils comprising selecting a sheet of porous expanded polytetrafluoroethylene having a perimeter and having a microstructure of nodes interconnected by fibrils, clamping around the perimeter of the sheet to restrain the sheet, and forming a portion of the sheet into a tubular shape by forcing a male form against the sheet thereby forcing a portion of the sheet into a female form, wherein the longitudinal axes of the male and female forms are substantially perpendicular to the sheet.
Claim 2
Independent Claim
96 words
A method for making a seamless tube of porous expanded polytetrafluoroethylene having a microstructure of nodes interconnected by fibrils comprising selecting a sheet of porous expanded polytetrafluoroethylene having a perimeter and having a microstructure of nodes interconnected by fibrils, clamping around the perimeter of the sheet to restrain the sheet, and forming a portion of the sheet into a tubular shape by forcing a male form against the sheet thereby forcing a portion of the sheet into a female form, wherein the longitudinal axes of the male and female forms are substantially perpendicular to the sheet.
Claim 3
Dependent Claim
33 words
A method according to claim 1 wherein the sheet of porous expanded polytetrafluoroethylene is heated to at least about 290° C. prior to forming a portion of the sheet into a tubular shape.
Claim 4
Dependent Claim
19 words
A method according to claim 1 wherein said tube has a wall thickness of less than about 0.20 mm.
Claim 5
Dependent Claim
19 words
A method according to claim 1 wherein said tube has a wall thickness of less than about 0.15 mm.
Claim 6
Dependent Claim
19 words
A method according to claim 1 wherein said tube has a wall thickness of less than about 0.10 mm.
Claim 7
Dependent Claim
19 words
A method according to claim 1 wherein said tube has a wall thickness of less than about 0.06 mm.
Claim 8
Dependent Claim
19 words
A method according to claim 1 wherein the tube has a wall thickness of less than about 0.08 mm.
Claim 9
Dependent Claim
32 words
A method according to claim 1 wherein the sheet has been heated to a temperature greater than the crystalline melt temperature of PTFE prior to forming the sheet into a tubular shape.
Claim 10
Dependent Claim
28 words
A method according to claim 8 wherein the sheet has a wall thickness and tube has a wall thickness of less than the wall thickness of the sheet.
Claim 11
Dependent Claim
19 words
A method according to claim 8 wherein the tube has a wall thickness of less than about 0.08 mm.
Claim 12
Dependent Claim
16 words
A method according to claim 1 wherein said sheet of porous expanded polytetrafluoroethylene has multiaxially-oriented fibrils.
Claim 13
Dependent Claim
40 words
A method according to claim 11 wherein said seamless tube of porous expanded polytetrafluoroethylene has a longitudinal axis and wherein the fibrils of the microstructure of the seamless tube are substantially oriented in a direction parallel to the longitudinal axis.
Claim 14
Dependent Claim
16 words
A method according to claim 1 wherein said sheet of porous expanded polytetrafluoroethylene has biaxially-oriented fibrils.
Claim 15
Dependent Claim
40 words
A method according to claim 11 wherein said seamless tube of porous expanded polytetrafluoroethylene has a longitudinal axis and wherein the fibrils of the microstructure of the seamless tube are substantially oriented in a direction parallel to the longitudinal axis.
References Cited (Backward Citations)
US2781552A
Cited
US3953566A
Cited
US4187390A
Cited
US4203938A
Cited
GB2033234A
Cited
US4419320A
Cited
US4482516A
Cited
US4563325A
Cited
EP0313263A2
Cited
US4877661A
Cited
US5026513A
Cited
US4957669A
Cited
WO1991013648A1
Cited
US5466509A
Cited
US5620763A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-04-11 | 2003-10-11 | 2004-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-04-11 | 2007-10-11 | 2008-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-04-11 | 2011-10-11 | 2012-04-11 | $7700.00 | Window Closed / Lapsed |