US3798294A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing battery separator sheet
Assignee: WR Grace and Co Conn
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Filing: 1972-02-10
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Granted: 1974-03-19
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Expires: 1992-02-10
Abstract
Abstract A plastic material is formed into a sheet suitable for conversion into a battery separator. An extruded sheet is formed by calendering to produce projections on at least one surface and thereafter its thickness is made more uniform. The method preferably includes transporting the calendered sheet on the calendering roll to partially harden it. The sheet is removed from the calendering roll by withdrawing the projections substantially straight out of the depressions in the calendering roll. The plastic material is preferably oil filled.
Inventors
- 👤 B Hollenbeck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:18
CPC Classifications
B; B29; B29C; B29C67/00; B29C67/20; B29C67/202; B29C43/00; B29C43/22; B29C43/222; B29C48/00; B29C48/03; B29C48/07; B29C48/08; B29C48/12; B29C48/13
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) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |