US4253968A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of inhibiting precipitation of calcium salts utilizing a copolymer of allyl monomers and maleic anhydride
Assignee: Calgon Corp
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Filing: 1979-08-17
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Granted: 1981-03-03
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Expires: 1999-08-17
Abstract
Abstract A process is provided for inhibiting the deposition of scale onto the surfaces of metals in a cooling water system. In the process a copolymer of maleic anhydride or maleic acid and certain allyl monomers is employed as the scale inhibiting composition. The copolymers are effective as scale inhibitors when employed in substoichiometric amounts.
Inventors
- 👤 Gordon E. Eastman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 02:39
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/12
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
144 words
A process for inhibiting the deposition of scale onto the surfaces of metals in open recirculating cooling water systems, said process consisting essentially of adding to the water in the cooling water system from about 0.5 parts per million to about 100 parts per million of a copolymer of maleic anhydride and an allyl compound having the formula: CH.sub.2 ═CH--CH.sub.2 --R wherein R is a radical selected from the group consisting of ##STR7## wherein R 1 is hydrogen or a straight or branched chain alkyl group having from 1 to 5 carbon atoms; R 2 is a straight or branched chain alkyl having from 1 to 5 carbon atoms; R 3 is hydrogen, and R 4 is hydrogen or ##STR8## wherein R 5 is hydrogen and R 6 is hydrogen or a straight or branched chain alkyl having from 1 to 5 carbon atoms.
Claim 2
Dependent Claim
144 words
A process for inhibiting the deposition of scale onto the surfaces of metals in open recirculating cooling water systems, said process consisting essentially of adding to the water in the cooling water system from about 0.5 parts per million to about 100 parts per million of a copolymer of maleic anhydride and an allyl compound having the formula: CH.sub.2 ═CH--CH.sub.2 --R wherein R is a radical selected from the group consisting of ##STR7## wherein R 1 is hydrogen or a straight or branched chain alkyl group having from 1 to 5 carbon atoms; R 2 is a straight or branched chain alkyl having from 1 to 5 carbon atoms; R 3 is hydrogen, and R 4 is hydrogen or ##STR8## wherein R 5 is hydrogen and R 6 is hydrogen or a straight or branched chain alkyl having from 1 to 5 carbon atoms.
Claim 3
Dependent Claim
13 words
The process of claim 1 in which the allyl monomer is allyl acetate.
Claim 4
Dependent Claim
31 words
The process of claim 2 in which the copolymer is added to the water in amounts to provide from about 0.5 ppm to about 100 ppm of copolymer in the water.
Claim 5
Dependent Claim
13 words
The process of claim 1 in which the allyl monomer is allyl alcohol.
Claim 6
Dependent Claim
25 words
The process of claim 1 in which the mole ratio of maleic anhydride monomer to allyl monomer in the copolymer is from 5:1 to 1:5.
Claim 7
Dependent Claim
30 words
The process according to claim 1 wherein the copolymer is added to the water in amounts so as to provide from 1 ppm to 25 ppm copolymer in the water.
Claim 8
Dependent Claim
31 words
The process of claim 1 in which the copolymer is added to the water in amounts to provide from about 1 ppm to about 25 ppm of copolymer in the water.
Claim 9
Dependent Claim
102 words
A process for inhibiting the deposition of calcium salts and other polyvalent metal salts onto the surfaces of metals in an open recirculating cooling water system, said process consisting essentially of adding to the water a copolymer of maleic anhydride and allyl acetate, the mole ratio of maleic anhydride units to allyl acetate units in the copolymer being about 1:1 and said copolymer having a molecular weight range of from about 500 to about 10,000, said copolymer being added to the water in an amount to provide a concentration of about 0.5 ppm to about 100 ppm of copolymer in the water.
Claim 10
Dependent Claim
102 words
A process for inhibiting the deposition of calcium salts and other polyvalent metal salts onto the surfaces of metals in an open recirculating cooling water system, said process consisting essentially of adding to the water a copolymer of maleic anhydride and allyl acetate, the mole ratio of maleic anhydride units to allyl acetate units in the copolymer being about 1:1 and said copolymer having a molecular weight range of from about 500 to about 10,000, said copolymer being added to the water in an amount to provide a concentration of about 0.5 ppm to about 100 ppm of copolymer in the water.
Claim 11
Dependent Claim
141 words
A process for inhibiting the deposition of scale onto the surface of metals in open recirculating cooling water systems, said process consisting essentially of adding to the cooling water system from about 0.5 parts per million to about 100 parts per million of a copolymer of maleic anhydride and an allyl compound having the formula: CH.sub.2 ═CH--CH.sub.2 --R wherein R is a radical selected from the group consisting of ##STR9## wherein R 1 is hydrogen or a straight or branched chain alkyl group having from 1 to 5 carbon atoms; R 2 is a straight or branched chain alkyl having from 1 to 5 carbon atoms; R 3 is hydrogen and R 4 is hydrogen or ##STR10## wherein R 5 is hydrogen and R 6 is hydrogen or a straight or branched chain alkyl having from 1 to 5 carbon atoms.
Claim 12
Dependent Claim
141 words
A process for inhibiting the deposition of scale onto the surface of metals in open recirculating cooling water systems, said process consisting essentially of adding to the cooling water system from about 0.5 parts per million to about 100 parts per million of a copolymer of maleic anhydride and an allyl compound having the formula: CH.sub.2 ═CH--CH.sub.2 --R wherein R is a radical selected from the group consisting of ##STR9## wherein R 1 is hydrogen or a straight or branched chain alkyl group having from 1 to 5 carbon atoms; R 2 is a straight or branched chain alkyl having from 1 to 5 carbon atoms; R 3 is hydrogen and R 4 is hydrogen or ##STR10## wherein R 5 is hydrogen and R 6 is hydrogen or a straight or branched chain alkyl having from 1 to 5 carbon atoms.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-02 | 1984-09-01 | 1985-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-02 | 1988-09-01 | 1989-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-02 | 1992-09-01 | 1993-03-03 | $7700.00 | Window Closed / Lapsed |