US3672821A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Inhibitor for aluminum in alkaline solutions
Assignee: Henkel AG and Co KGaA
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Filing: 1971-02-16
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Granted: 1972-06-27
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Expires: 1991-02-16
Abstract
Abstract A METHOD OF INHIBITING THE CORROSION OF METALLIC ALUMINUM DURING ITS TREATMENT WITH ALKALINE SOLUTIONS. AS THE INHIBITOR IN THE ALKALINE SOLUTION, ACCORDING TO THE INVENTION POLYACRYLIC ACIDS HAVING A SPECIFIC VISCOSITY IN THE RANGE OF 0.07 TO 0.90, PREFERABLY 0.09 TO 0.20, ARE USED IN A PREFERRED AMOUNT OF 0.05 TO 0.5% BY WEIGHT, BASED ON THE WEIGHT OF THE ALKALINE SOLUTION. INSTEAD OF THE POLYACRYLIC ACIDS THEIR WATER-SOLUBLE ALKALI SALTS CAN BE USED. BY THE PRESENT INVENTION THE UNDESIRED SIDE EFFECTS OF ALKALI SILICATE INHIBITORS, SUCH AS INCRUSTATION OF THE ALUMINUM, CAN BE AVOIDED.
Inventors
- 👤 Hans-Joachim Schlussler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:31
CPC Classifications
C; C23; C23F; C23F11/00; C23F11/06
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) | 1975-06-27 | 1975-12-27 | 1976-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-27 | 1979-12-27 | 1980-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-27 | 1983-12-27 | 1984-06-27 | $7700.00 | Window Closed / Lapsed |