Patent US5167890A successfully refreshed from Google Patents.
US5167890A
Expired / Lapsed
US
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Monoaxially stretched shaped article of polytetrafluoroethylene and process for producing the same
Assignee: Lenzing AG
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Filing: 1990-03-26
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Granted: 1992-12-01
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Expires: 2010-03-26
Abstract
Abstract To produce a monoaxially stretched shaped article of polytetrafluoroethylene (PTFE), a pasty mass containing PTFE powder is continuously shaped to a shaped body, which is fed over a plurality of rollers or rolls, heated and stretched. The shaped body is heated to a temperature of between 327° and 450° C. prior to stretching strain, it is sintered simultaneously and is then stretched. This process allows for the production of a monoaxially stretched shaped article of PTFE which has strength values in the stretching direction of at least 500 N/mm 2 and a delivery of between 1.80 and 2.30 g/cm 3 .
Inventors
- 👤 Franz Sasshofer
- 👤 Reinhard Reinmuller
- 👤 Christian H. F. Schlossnikl
- 👤 Adalbert G. Wimmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:20
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B29; B29C; B29C55/00; B29C55/02; B29C55/04; B29C55/06; D; D01; D01F; D01F6/00; D01F6/02; D01F6/08; D01F6/12; B29K; B29K2027/00; B29K2027/12; B29K2027/18; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
120 words
The process for the production of a monoaxially stretched shaped article consisting essentially of polytetrafluoroethylene (PTFE) and having strength values in the stretching direction of at least 500 N/mm 2 and a density of between 1.80 and 2.30 g/cm 3 , which process comprises: providing a pasty mass containing PTFE powder, continuously forming said pasty mass to a shaped body, guiding said shaped body over a plurality of rollers or rolls, and heating and stretching said shaped body, wherein the improvement comprises heating said shaped body to a temperature of between 327° and 450° C. and simultaneously sintering said body without stretching, and thereafter stretching said body while said body is at a temperature of between 327° and 450° C.
Claim 2
Dependent Claim
120 words
The process for the production of a monoaxially stretched shaped article consisting essentially of polytetrafluoroethylene (PTFE) and having strength values in the stretching direction of at least 500 N/mm 2 and a density of between 1.80 and 2.30 g/cm 3 , which process comprises: providing a pasty mass containing PTFE powder, continuously forming said pasty mass to a shaped body, guiding said shaped body over a plurality of rollers or rolls, and heating and stretching said shaped body, wherein the improvement comprises heating said shaped body to a temperature of between 327° and 450° C. and simultaneously sintering said body without stretching, and thereafter stretching said body while said body is at a temperature of between 327° and 450° C.
Claim 3
Dependent Claim
20 words
A process as set forth in claim 1, wherein said shaped body is heated to between 350° and 390° C.
Claim 4
Dependent Claim
57 words
A process as set forth in claim 1 to be performed in an arrangement comprising a heated roll or pairs of rollers and an unheated take off unit, wherein said shaped body is stretched between said roll or pairs of rollers heated to a temperature of between 327° and 450° C. and said unheated take off unit.
Claim 5
Dependent Claim
23 words
A process as set forth in claim 3, wherein at least one of said rolls is heated to between 350° and 390° C.
Claim 6
Dependent Claim
22 words
A process as set forth in claim 1, wherein said shaped body is stretched at a ratio of between 1:5 and 1:30.
Claim 7
Dependent Claim
22 words
A process as set forth in claim 1, wherein said shaped body is stretched at a ratio of between 1:10 and 1:20.
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) | 1995-12-01 | 1996-06-01 | 1996-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-12-01 | 2000-06-01 | 2000-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-12-01 | 2004-06-01 | 2004-12-01 | $7700.00 | Window Closed / Lapsed |