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US3801692A
Expired / Lapsed
US
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Production of novel open-celled microporous film
Assignee: Celanese Corp
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Filing: 1969-11-13
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Granted: 1974-04-02
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Expires: 1989-11-13
Abstract
Abstract PORE AREA, AND BETTER THERMAL STABILITY THAN MICROPOROUS FILMS OF THE PRIOR ART. THE NOVEL PROCESS FOR MAKING THE OPEN-CELLED MICROPOROUS FILM INVOLVES THE CONDSECUTIVE STEPS OF COLD STRETCHING AT A TEMPERATURE BELOW 0*C., FOR EXAMPLE -10*C. TO -40*C., HOT STRETCHING, AND HEAT SETTING A NON-POROUS, CRYSTALLINE, ELASTIC FILM. THE RESULTING OPEN-CELLED MICROPOROUS FILM HAS A GREATER NUMBER OF PORES, A MORE UNIFORM PORE CONCENTRATION OR DISTRIBUTION, A LARGER TOTAL
Inventors
- 👤 D Zimmerman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:12
CPC Classifications
B; B29; B29C; B29C55/00; B29C55/02; B29C55/04; B29C55/06; B29C55/065; B29C55/023; B29D; B29D7/00; B29L; B29L2023/00; B29L2023/001
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-01 | 1977-10-01 | 1978-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-01 | 1981-10-01 | 1982-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-01 | 1985-10-01 | 1986-04-02 | $7700.00 | Window Closed / Lapsed |