US2578522A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of preparing unsupported films of polytetrafluoroethylene
Assignee: EIDP Inc
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Filing: 1949-06-08
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Granted: 1951-12-11
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Expires: 1969-06-08
Abstract
No abstract record available.
Inventors
- 👤 Edgar Donald Edwards
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 17:48
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B29; B29C; B29C43/00; B29C43/006; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
58 words
A METHOD OF PREPARING UNSUPPORTED FILMS WHICH COMPRISES ADDING A COAGULANT TO AN AQUEOUS SUSPENSOID OF POLYTETRAFLUORETHYLENE, RAPIDLY MIXING THE AQUEOUS SUSPENSOID AND THE COAGULANT TO FORM SOFT CURDS, SEPARATING THESE CURDS FROM THE WATER AND COAGULANT, AND PASSING THESE CURD-LIKE MASSES BETWEEN AND IN CONTACT WITH PRESSURE ROLLS AT A TEMPERATURE BELOW THE FUSION POINT OF POLYTETRAFLUOROETHYLENE.
Claim 2
Independent Claim
58 words
A METHOD OF PREPARING UNSUPPORTED FILMS WHICH COMPRISES ADDING A COAGULANT TO AN AQUEOUS SUSPENSOID OF POLYTETRAFLUORETHYLENE, RAPIDLY MIXING THE AQUEOUS SUSPENSOID AND THE COAGULANT TO FORM SOFT CURDS, SEPARATING THESE CURDS FROM THE WATER AND COAGULANT, AND PASSING THESE CURD-LIKE MASSES BETWEEN AND IN CONTACT WITH PRESSURE ROLLS AT A TEMPERATURE BELOW THE FUSION POINT OF POLYTETRAFLUOROETHYLENE.
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) | 1954-12-10 | 1955-06-11 | 1955-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-12-10 | 1959-06-11 | 1959-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-12-10 | 1963-06-11 | 1963-12-11 | $7700.00 | Window Closed / Lapsed |