US3897209A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corrosion inhibitors for metals in aqueous systems
Assignee: FMC Corp
•
Filing: 1972-12-04
•
Granted: 1975-07-29
•
Expires: 1992-12-04
Abstract
Abstract Method for inhibiting the corrosion and scale forming tendencies of water or an aqueous system which comprises treating the water or aqueous system with from 0.1 to 500 p.p.m. of an additive combination comprising zinc and hydrolysed polymaleic anhydride.
Inventors
- 👤 Arthur Harris
- 👤 John Burrows
- 👤 Thomas Ivor Jones
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:43
CPC Classifications
C; C23; C23F; C23F11/00; C23F11/08; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/105
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
90 words
A PROCESS FOR INHIBITING THE CORROSIVE ATTACK OF AN AQUEOUS SYSTEM ON METALLIC SURFACES WHICH COMPRISES ADDING TO THE AQUEOUS SYSTEM FROM 0.1 TO 500 P.P.M. OF A COMPOSITION COMPRISING FROM 2.5 TO 80% BY WEIGHT OF A WATER SOLUBLE ZINC COMPOUND (CLACULATED AS ZN++) AND 97.5 TO 20% BY WEIGHT OF A HYDROLYZED POLYMALEIC AHYDRIDE, OR OF A WATER SOLUBLE SALT OF SUCH A HYDROLYZED POLYMALEIC ANHYDRIDE, THE AVERAGE MOLECULAR WEIGHT OF THE HYDROLYZED POLYMALEIC ANHYDRIDE OR THE WATER SOLUBLE SALT THEREOF BEING FROM BEING FROM 300 TO 5000.
Claim 2
Dependent Claim
90 words
A PROCESS FOR INHIBITING THE CORROSIVE ATTACK OF AN AQUEOUS SYSTEM ON METALLIC SURFACES WHICH COMPRISES ADDING TO THE AQUEOUS SYSTEM FROM 0.1 TO 500 P.P.M. OF A COMPOSITION COMPRISING FROM 2.5 TO 80% BY WEIGHT OF A WATER SOLUBLE ZINC COMPOUND (CLACULATED AS ZN++) AND 97.5 TO 20% BY WEIGHT OF A HYDROLYZED POLYMALEIC AHYDRIDE, OR OF A WATER SOLUBLE SALT OF SUCH A HYDROLYZED POLYMALEIC ANHYDRIDE, THE AVERAGE MOLECULAR WEIGHT OF THE HYDROLYZED POLYMALEIC ANHYDRIDE OR THE WATER SOLUBLE SALT THEREOF BEING FROM BEING FROM 300 TO 5000.
Claim 3
Dependent Claim
35 words
A process according to claim 1 in which the composition comprises from 10 to 60% by weight of a water soluble zinc compound and from 90 to 40% by weight of a hydrolyzed polymaleic anhydride.
Claim 4
Dependent Claim
22 words
A process according to claim 1 wherein the concentration of said composition in said aqueous system is between 1 and 200 p.p.m.
Claim 5
Dependent Claim
60 words
A process according to claim 1 in which there is added to the aqueous system from 1 to 200 parts per million of a composition comprising from 10 to 60% by weight of a water soluble zinc compound (calculated as Zn ) and from 90 to 40% by weight of a mixture of hydrolyzed polymaleic anhydride of the general formula
Claim 6
Dependent Claim
28 words
A process according to claim 4 in which R1 and R2 are the same or different and are selected from hydrogen, C6H5-CH2-radicals, CH3-C6H4-CH2- radicals, C6H5- radicals or (CH3)3C-radicals.
References Cited (Backward Citations)
US3385834A
Cited
US3382056A
Cited
US3699047A
Cited
US3706717A
Cited
US3810834A
Cited
US3658710A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-28 | 1979-01-27 | 1979-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-28 | 1983-01-27 | 1983-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-28 | 1987-01-27 | 1987-07-29 | $7700.00 | Window Closed / Lapsed |