US4936987A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Synergistic scale and corrosion inhibiting admixtures containing carboxylic acid/sulfonic acid polymers
Assignee: ECC SPECIALTY CHEMICALS Inc
•
Filing: 1988-05-16
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Granted: 1990-06-26
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Expires: 2008-05-16
Abstract
Abstract The instant invention is directed to an admixture, and its use in inhibiting scale and corrosion in aqueous systems, comprising: (a) a water-soluble polymer having a weight average molecular weight of less than 25,000, as determined by low angle laser light scattering, comprising an unsaturated carboxylic acid and an unsaturated sulfonic acid, or their salts, having a ratio of 1:20 to 20:1, and (b) at least one compound selected from the group consisting of water-soluble polycarboxylates, phosphonates, phosphates, polyphosphates, metal salts and sulfonates. The instant invention is also directed to a method of inhibiting the formation of insoluble alluvial, metal oxide and metal hydroxide deposits in an aqueous system, comprising adding to the system at least 0.1 mg/l of a water-soluble polymer having a weight average molecular weight of less than 25,000, as determined by low angle laser light scattering, comprising an unsaturated carboxylic acid and an unsaturated sulfonic acid, or their salts, having a ratio of 1:20 to 20:1 and a phosphonate.
Inventors
- 👤 Leonard J. Persinski
- 👤 Jerry L. Walker
- 👤 Bennett P. Boffardi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:42
CPC Classifications
C; C23; C23F; C23F11/00; C23F11/08; C23F11/10; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/12; C02F5/14; C23F11/173; C23F14/00; C23F14/02; F; F02; F02B; F02B75/00; F02B75/02; F02B2075/022; F02B2075/027
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
245 words
A method of inhibiting the precipitation of scale-forming salts of alkaline earth metal cations, including calcium phosphate, in an aqueous system, comprising adding to said aqueous system at least 0.1 mg/l of an admixture comprising: (a) a water-soluble polymer having a weight average molecular weight of less than 25,000, as determined by low angle laser light scattering, selected from the group of polymers comprising: (i) an unsaturated mono-carboxylic acid selected from the group consisting of acrylic acid and methacrylic acid; and (ii) an unsaturated sulfonic acid selected from the group consisting of 2-acrylamido-2-methylpropyl sulfonic acid and 2-methacrylamido-2-methylpropyl sulfonic acid; wherein the weight ratio of (i):(ii) ranges from 1:4 to 4:1; and (b) at least one member selected from the group consisting of: phosphino carboxylic acid, low molecular weight homopolymers of maleic acid or anhydride having a weight average molecular weight of less than 25,000, low molecular weight homopolymers of acrylic acid having a weight average molecular weight of less than about 25,000, low molecular weight copolymers of acrylamide and acrylate having a weight average molecular weight of less than about 10,000, copolymers of acrylic acid and 2-hydroxypropyl acrylate having a weight average molecular weight of less than about 10,000, copolymers of maleic acid or anhydride and sulfonated styrene having a weight average molecular weight of less than about 10,000 and sulfonated polystyrenes having a weight average molecular weight of less than about 10,000; wherein the weight ratio of (a):(b) is about 1:10 to about 10:1.
Claim 2
Independent Claim
245 words
A method of inhibiting the precipitation of scale-forming salts of alkaline earth metal cations, including calcium phosphate, in an aqueous system, comprising adding to said aqueous system at least 0.1 mg/l of an admixture comprising: (a) a water-soluble polymer having a weight average molecular weight of less than 25,000, as determined by low angle laser light scattering, selected from the group of polymers comprising: (i) an unsaturated mono-carboxylic acid selected from the group consisting of acrylic acid and methacrylic acid; and (ii) an unsaturated sulfonic acid selected from the group consisting of 2-acrylamido-2-methylpropyl sulfonic acid and 2-methacrylamido-2-methylpropyl sulfonic acid; wherein the weight ratio of (i):(ii) ranges from 1:4 to 4:1; and (b) at least one member selected from the group consisting of: phosphino carboxylic acid, low molecular weight homopolymers of maleic acid or anhydride having a weight average molecular weight of less than 25,000, low molecular weight homopolymers of acrylic acid having a weight average molecular weight of less than about 25,000, low molecular weight copolymers of acrylamide and acrylate having a weight average molecular weight of less than about 10,000, copolymers of acrylic acid and 2-hydroxypropyl acrylate having a weight average molecular weight of less than about 10,000, copolymers of maleic acid or anhydride and sulfonated styrene having a weight average molecular weight of less than about 10,000 and sulfonated polystyrenes having a weight average molecular weight of less than about 10,000; wherein the weight ratio of (a):(b) is about 1:10 to about 10:1.
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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) | 1993-06-25 | 1993-12-25 | 1994-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-25 | 1997-12-25 | 1998-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-25 | 2001-12-25 | 2002-06-26 | $7700.00 | Window Closed / Lapsed |