US4519920A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Maleic acid/(meth)acrylic acid copolymers useful as calcium ion capturing agents
Assignee: Kao Corp
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Filing: 1984-04-09
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Granted: 1985-05-28
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Expires: 2004-04-09
Abstract
Abstract A copolymer of maleic acid (MA) and (meth)acrylic acid (AA), or a salt thereof, wherein the molar ratio (MA/AA) γ of the constituent monomers is 1.15 to 2.7, the average molecular weight MW is 1000 to 8000, and (γ)×(MW) is at least 3000. The copolymer is useful as a calcium ion capturing agent, in a process for treating water to inhibit formation of scale surfaces contacted by the water.
Inventors
- 👤 Yasuhisa Fukumoto
- 👤 Noboru Moriyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:50
CPC Classifications
C; C08; C08F; C08F222/00; C08F222/02; C02; C02F; C02F5/00; C02F5/08; C02F5/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
124 words
A process for treating water to inhibit formation of scale on surfaces contacted by the water, which comprises: mixing in the water an effective amount of a calcium ion capturing agent for chelating the calcium ions contained in the water to prevent deposition of scale on surfaces contacted by the water, said calcium ion capturing agent being an alkali metal salt of a copolymer of maleic acid (MA) and a monomer (AA) selected from the group consisting of acrylic acid and methacrylic acid, wherein the mol ratio (γ) of the monomer units MA/AA is from 1.15 to 2.7, the number average molecular weight (MW) of the copolymer is from 1000 to 8000, and the product of (γ) multiplied by (MW) is at least 3000.
Claim 2
Dependent Claim
124 words
A process for treating water to inhibit formation of scale on surfaces contacted by the water, which comprises: mixing in the water an effective amount of a calcium ion capturing agent for chelating the calcium ions contained in the water to prevent deposition of scale on surfaces contacted by the water, said calcium ion capturing agent being an alkali metal salt of a copolymer of maleic acid (MA) and a monomer (AA) selected from the group consisting of acrylic acid and methacrylic acid, wherein the mol ratio (γ) of the monomer units MA/AA is from 1.15 to 2.7, the number average molecular weight (MW) of the copolymer is from 1000 to 8000, and the product of (γ) multiplied by (MW) is at least 3000.
Claim 3
Dependent Claim
14 words
A process as claimed in claim 1 wherein (MW) is from 1500 to 6000.
Claim 4
Dependent Claim
14 words
A process as claimed in claim 1 wherein (MW) is from 2000 to 5000.
Claim 5
Dependent Claim
21 words
A process as claimed in claim 1 wherein the mol ratio (γ) of the monomer units is from 1.3 to 2.6.
Claim 6
Dependent Claim
20 words
A process as claimed in claim 1 wherein the product of (γ) multiplied by (MW) is from 4000 to 6000.
Claim 7
Dependent Claim
21 words
A process as claimed in claim 1 in which the water is boiler feed water or circulating water containing calcium ions.
References Cited (Backward Citations)
US4175066A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-27 | 1988-11-26 | 1989-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-27 | 1992-11-26 | 1993-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-27 | 1996-11-26 | 1997-05-28 | $7700.00 | Window Closed / Lapsed |