US2521674A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of preparing organosiloxane resins
Assignee: Dow Chemical Co
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Filing: 1947-03-29
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Granted: 1950-09-12
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Expires: 1967-03-29
Abstract
No abstract record available.
Inventors
- 👤 Edgar C Britton
- 👤 Laurence W Byers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:12
CPC Classifications
C; C08; C08G; C08G77/00; C08G77/04; C08G77/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
104 words
THE METHOD OF INCREASING THE AVERAGE MOLECULAR WEIGHT OF AN ORGANOSILOXANE POLYMER, CONTAINING AN AVERAGE OF FROM 1 TO 1.9 HYDROCARBON RADICALS PER ATOM OF SILICON AS THE ORGANIC PORTIONS OF THE MOLECULE, WHICH COMPRISES TREATING THE SAID POLYMER, IN THE PRESENCE OF AN INERT SOLVENT FOR THE POLYMER STARTING MATERIAL, WITH SUCCESSIVE APPRECIABLE PORTIONS OF AN ALKALI METAL HYDROXIDE IN AMOUNT TOTALING NOT MORE THAN 6 GRAM MOLECULAR EQUIVALENTS OF THE ALKALI PER 400 GRAM ATOMIC WEIGHTS OF SILICON IN THE ORGANOSILOXANE POLYMER UNDER TREATMENT, INTERMITTENTLY REMOVING AN APPRECIABLE PORTION OF THE SOLVENT FROM THE REACTION MIXTURE AND RECOVERING A COMPLEX ORGANOSILOXANE POLYMER.
Claim 2
Independent Claim
104 words
THE METHOD OF INCREASING THE AVERAGE MOLECULAR WEIGHT OF AN ORGANOSILOXANE POLYMER, CONTAINING AN AVERAGE OF FROM 1 TO 1.9 HYDROCARBON RADICALS PER ATOM OF SILICON AS THE ORGANIC PORTIONS OF THE MOLECULE, WHICH COMPRISES TREATING THE SAID POLYMER, IN THE PRESENCE OF AN INERT SOLVENT FOR THE POLYMER STARTING MATERIAL, WITH SUCCESSIVE APPRECIABLE PORTIONS OF AN ALKALI METAL HYDROXIDE IN AMOUNT TOTALING NOT MORE THAN 6 GRAM MOLECULAR EQUIVALENTS OF THE ALKALI PER 400 GRAM ATOMIC WEIGHTS OF SILICON IN THE ORGANOSILOXANE POLYMER UNDER TREATMENT, INTERMITTENTLY REMOVING AN APPRECIABLE PORTION OF THE SOLVENT FROM THE REACTION MIXTURE AND RECOVERING A COMPLEX ORGANOSILOXANE POLYMER.
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) | 1953-09-11 | 1954-03-13 | 1954-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-09-11 | 1958-03-13 | 1958-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-09-11 | 1962-03-13 | 1962-09-12 | $7700.00 | Window Closed / Lapsed |