EP0313263A2
Expired / Lapsed
EP
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Rapid recoverable PTFE and a process for its manufacture
Assignee: W.L. Gore and Associates Inc
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Filing: 1988-10-12
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Granted: —
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Expires: 2008-10-12
Abstract
Abstract This invention relates to porous polytetrafluoroethylene (PTFE) materials having the property of rapid recovery and a process 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. The process comprises extruding a billet of a mixture of coagulated dispersion of PTFE and liquid lubricant, removing the lubricant, stretching the material longitudinally and maintaining it at a temperature between 35°C and the crystalline melt point during stretching, compressing the PTFE in the direction of fibrils to reduce its size, restraining the PTFE in its compressed state, and heating the compressed PTFE.
Inventors
- 👤 Wayne D. House
- 👤 David J. Myers
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 03:32
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
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
30 words
A porous shaped article consisting essentially of polytetrafluoroethylene (PTFE), said article having a microstructure of nodes interconnected by fibrils, said article having a rapid recovery of more than about 5.5%.
Claim 2
Dependent Claim
30 words
A porous shaped article consisting essentially of polytetrafluoroethylene (PTFE), said article having a microstructure of nodes interconnected by fibrils, said article having a rapid recovery of more than about 5.5%.
Claim 3
Dependent Claim
18 words
A porous shaped article according to claim 1, wherein substantially all of said fibrils have a bent appearance.
Claim 4
Dependent Claim
42 words
An extruded, expanded article, heat treated above its crystalline melt point made of a material consisting essentially of PTFE, said porous PTFE having been subsequently compressed at least 50% in the direction in which rapid recoverable characteristics are desired, restrained and heated.
Claim 5
Dependent Claim
42 words
An extruded, expanded article, heat treated above its crystalline melt point made of a material consisting essentially of PTFE, said porous PTFE having been subsequently compressed at least 50% in the direction in which rapid recoverable characteristics are desired, restrained and heated.
Claim 6
Dependent Claim
28 words
An article as claimed in claim 3 wherein the material was subsequently compressed at least 60%, or 75%, or 90% in the direction of desired rapid recoverable characteristics.
Claim 7
Dependent Claim
77 words
A porous PTFE article in the form of a tube with a microstructure of nodes and fibrils wherein: a) the tube has been compressed to less than 50% of its original length and restrained; b) the tube has been heated at an elevated temperature for a period of time; c) said tube has been subsequently cooled; and d) said tube has been stretched to approximately its original length having a rapid recovery in excess of about 5.5%.
Claim 8
Dependent Claim
77 words
A porous PTFE article in the form of a tube with a microstructure of nodes and fibrils wherein: a) the tube has been compressed to less than 50% of its original length and restrained; b) the tube has been heated at an elevated temperature for a period of time; c) said tube has been subsequently cooled; and d) said tube has been stretched to approximately its original length having a rapid recovery in excess of about 5.5%.
Claim 9
Dependent Claim
39 words
An article according to any one of claims 1 to 5 in which said article has a rapid recovery of greater than 6%, or 8%, or 10%, or 15%, or 20%, or 22%, or 25%, or 30% or 50%.
Claim 10
Dependent Claim
19 words
An article according to any preceding claim in the shape of a tube having smooth inside and outside surfaces.
Claim 11
Dependent Claim
16 words
An article according to claim 7, in which the inside surface and the outside surface differ.
Claim 12
Dependent Claim
23 words
An article according to claim 1 which has been formed as a tube and subsequently slit longitudinally and opened to form a sheet.
Claim 13
Dependent Claim
19 words
An article according to claim 1 in the form of a sheet, a rod, a film or a filament.
Claim 14
Dependent Claim
28 words
An article as claimed in claim 9 or 10 having a rapid recover greater than 5.5%, or 10%, or 20%, or 25%, or 30%, or 50% or 75%.
Claim 15
Dependent Claim
80 words
A process for making rapidly recoverable PTFE material comprising extruding a preformed billet of a mixture of coagulated dispersion of PTFE and liquid lubricant, expanding said material after removal of liquid lubricant by stretchig said material longitudinally and maintaining said material at a temperature between 35°C and the crystalline melt point during stretching, compressing said extruded and expanded PTFE in the direction of fibrils to reduce its size, restraining said PTFE in its compressed state, and heating said compressed PTFE.
Claim 16
Dependent Claim
80 words
A process for making rapidly recoverable PTFE material comprising extruding a preformed billet of a mixture of coagulated dispersion of PTFE and liquid lubricant, expanding said material after removal of liquid lubricant by stretchig said material longitudinally and maintaining said material at a temperature between 35°C and the crystalline melt point during stretching, compressing said extruded and expanded PTFE in the direction of fibrils to reduce its size, restraining said PTFE in its compressed state, and heating said compressed PTFE.
Claim 17
Dependent Claim
21 words
A process as claimed in claim 12 wherein said compressed PTFE is heated to a temperature above its crystalline melt point.
Claim 18
Dependent Claim
69 words
A process for manufacturing a porous PTFE 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 it 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 19
Dependent Claim
69 words
A process for manufacturing a porous PTFE 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 it 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 20
Dependent Claim
14 words
A process as claimed in claim 12 wherein said compressed PTFE is not heated.
Claim 21
Dependent Claim
19 words
A porous shaped article according to claim 2 wherein said fibrils have a V/H ratio of at least 0.15,
References Cited (Backward Citations)
No citation records indexed.
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