US2979494A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing essentially cis rubbery polyisoprene
Assignee: Bridgestone Firestone Inc
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Filing: 1955-09-01
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Granted: 1961-04-11
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Expires: 1975-09-01
Abstract
No abstract record available.
Inventors
- 👤 Richard S Stearns
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:24
CPC Classifications
C; C08; C08F; C08F136/00; C08F136/02; C08F136/04; C08F136/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
49 words
METHOD WHICH COMPRISES SUBJECTING IN A VACUO A MIXTURE CONSISTING ESSENTIALLY OF ISOPRENE AND METALLIC LITHIUM TO A TEMPERATURE SUFFICIENT TO INITIATE POLYMERIZATION OF SAID ISOPRENE IN THE RANGE OF ABOUT 0*C. TO 30*C. AND COMPLETING SAID POLYMERIZATION AT AN APPRECIABLY REDUCED TEMPERATURE BUT SUBSTANTIALLY NO LOWER THAN ABOUT-20*C.
Claim 2
Dependent Claim
49 words
METHOD WHICH COMPRISES SUBJECTING IN A VACUO A MIXTURE CONSISTING ESSENTIALLY OF ISOPRENE AND METALLIC LITHIUM TO A TEMPERATURE SUFFICIENT TO INITIATE POLYMERIZATION OF SAID ISOPRENE IN THE RANGE OF ABOUT 0*C. TO 30*C. AND COMPLETING SAID POLYMERIZATION AT AN APPRECIABLY REDUCED TEMPERATURE BUT SUBSTANTIALLY NO LOWER THAN ABOUT-20*C.
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) | 1964-04-10 | 1964-10-10 | 1965-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-04-10 | 1968-10-10 | 1969-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-04-10 | 1972-10-10 | 1973-04-11 | $7700.00 | Window Closed / Lapsed |