Patent US4589985A successfully refreshed from Google Patents.
US4589985A
Expired / Lapsed
US
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Polyelectrolyte and surfactant compositions for controlling alkaline earth metal scales
Assignee: ECC SPECIALTY CHEMICALS Inc
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Filing: 1984-12-03
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Granted: 1986-05-20
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Expires: 2004-12-03
Abstract
Abstract The instant invention is directed to a method of inhibiting the precipitation and deposition of alkaline earth metal scales in an aqueous system, comprising adding to said system an effective amount of (a) an anionic polyelectrolyte; and (b) an anionic surfactant, wherein said polyelectrolyte/surfactant ratio ranges from 1000:1 to 1:10, by weight.
Inventors
- 👤 Monica A. Yorke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:29
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/12; C02F5/14
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
133 words
A method of inhibiting the precipitation and deposition of alkaline earth metal scales including calcium carbonate in an aqueous system having a pH of at least 8, comprising adding to said system 0.1 to 100 ppm of (a) a water-soluble anionic polyelectrolyte selected from the group of copolymers containing from about 95 mole percent to about 25 mole percent acrylic acid or methacrylic acid and containing from about 5 mole percent to about 75 percent 2-acrylamido-2-methylpropyl sulfonic acid or 2-methacrylamido-2-methylpropyl sulfonic acid, and salts of these polymers; and (b) an anionic surfactant selected from octylphenoxy polyethoxy ethyl phosphate, and sodium or potassium salts thereof, wherein the anionic polyelectrolyte/anionic surfactant ratio ranges from 50:1 to 1:5, by weight, and wherein the molecular weight of said anionic polyelectrolyte ranges from about 1000 to about 20,000.
Claim 2
Independent Claim
133 words
A method of inhibiting the precipitation and deposition of alkaline earth metal scales including calcium carbonate in an aqueous system having a pH of at least 8, comprising adding to said system 0.1 to 100 ppm of (a) a water-soluble anionic polyelectrolyte selected from the group of copolymers containing from about 95 mole percent to about 25 mole percent acrylic acid or methacrylic acid and containing from about 5 mole percent to about 75 percent 2-acrylamido-2-methylpropyl sulfonic acid or 2-methacrylamido-2-methylpropyl sulfonic acid, and salts of these polymers; and (b) an anionic surfactant selected from octylphenoxy polyethoxy ethyl phosphate, and sodium or potassium salts thereof, wherein the anionic polyelectrolyte/anionic surfactant ratio ranges from 50:1 to 1:5, by weight, and wherein the molecular weight of said anionic polyelectrolyte ranges from about 1000 to about 20,000.
Claim 3
Dependent Claim
22 words
The method of claim 1, wherein said anionic polyelectrolyte is a copolymer of acrylic acid and 2-acrylamido-2-methylpropyl sulfonic acid and salts thereof.
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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) | 1989-05-19 | 1989-11-18 | 1990-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-19 | 1993-11-18 | 1994-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-19 | 1997-11-18 | 1998-05-20 | $7700.00 | Window Closed / Lapsed |