Patent US3823221A successfully refreshed from Google Patents.
US3823221A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of a char reinforcing agent from pyrolyzed scrap rubber
Assignee: Bridgestone Firestone Inc
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Filing: 1972-03-20
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Granted: 1974-07-09
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Expires: 1992-03-20
Abstract
Abstract THE INVENTION RELATES TO A RUBBER REINFORCING AGENT DERIVED FROM VULCANIZED SCRAP RUBBER. THE SCRAP RUBBER IS CHARRED, TREATED FOR REMOVAL OF OIL AND THEN TREATED WITH ACID TO REMOVE METAL COMPOUNDS. THIS IS THEN REDUCED TO FINE PARTICLE SIZE. THE PRODUCT HAS BEEN FOUND TO BE A VERY SATISFACTORY RUBBER-REINFORCING AGENT.
Inventors
- 👤 L Wakefield
- 👤 E Kay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:30
CPC Classifications
C; C10; C10B; C10B53/00; C10B53/07; C08; C08K; C08K3/00; C08K3/02; C08K3/04; C09; C09C; C09C1/00; C09C1/44; C09C1/48; C09C1/482; C01; C01P; C01P2006/00; C01P2006/80; Y; Y02; Y02P; Y02P20/00; Y02P20/141; Y02P20/143
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) | 1977-07-08 | 1978-01-07 | 1978-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-08 | 1982-01-07 | 1982-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-08 | 1986-01-07 | 1986-07-09 | $7700.00 | Window Closed / Lapsed |