Patent US4072607A successfully refreshed from Google Patents.
US4072607A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of anionic polymers for use as scale inhibitors and anti-precipitants
Assignee: Wyeth Holdings LLC
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Filing: 1976-10-26
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Granted: 1978-02-07
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Expires: 1996-10-26
Abstract
Abstract An anionic polymer of acrylamide having a skewed molecular weight distribution such that about 60% of said polymer has a molecular weight of about 500 to 2,000 and about 10% of said polymer has a molecular weight of about 4,000 to 12,000 has been discovered. The process of manufacturing this skewed molecular weight distribution anionic polymer is described. Its use as a scale inhibitor for controlling the deposition of adherent scales on the walls of vessels or pipes, and as an anti-precipitant for keeping alkaline earth cations in solution is also described. The use of the anionic polymer of acrylamide consisting of a skewed molecular weight could be used in recirculating water systems, boilers, and in evaporative and reverse osmosis desalination systems.
Inventors
- 👤 Arthur Maurice Schiller
- 👤 Richard Martin Goodman
- 👤 Roger Edgar Neff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:34
CPC Classifications
C; C08; C08F; C08F220/00; C08F220/02; C08F220/04; C08F220/06; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/12
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
123 words
A process for controlling the deposition of adherent scale on the walls of vessels or pipes in a water system, comprising adding to the water in said system an effective amount of an anionic copolymer composed of acrylate and acrylamide linkages in mole ratios of about 20:1 to about 1:1 having a skewed molecular weight distribution such that at least about 60% of said copolymer has a molecular weight of about 500 to 2,000, at least about 10% of said polymer has a molecular weight of about 4,000 to 12,000 and the remainder of said copolymer having a molecular weight of about 2000-4000 on a gel permeation chromatograph wherein the control of said scale is substantially provided by the lower molecular weight material.
Claim 2
Dependent Claim
123 words
A process for controlling the deposition of adherent scale on the walls of vessels or pipes in a water system, comprising adding to the water in said system an effective amount of an anionic copolymer composed of acrylate and acrylamide linkages in mole ratios of about 20:1 to about 1:1 having a skewed molecular weight distribution such that at least about 60% of said copolymer has a molecular weight of about 500 to 2,000, at least about 10% of said polymer has a molecular weight of about 4,000 to 12,000 and the remainder of said copolymer having a molecular weight of about 2000-4000 on a gel permeation chromatograph wherein the control of said scale is substantially provided by the lower molecular weight material.
Claim 3
Dependent Claim
12 words
A process according to claim 1 wherein the acrylate is sodium acrylate.
Claim 4
Dependent Claim
16 words
A process according to claim 1 wherein the adherent scale is in a recirculating water system.
Claim 5
Dependent Claim
14 words
A process according to claim 1 wherein the adherent scale is in a boiler.
Claim 6
Dependent Claim
15 words
A process according to claim 1 wherein the adherent scale is in a desalination system.
Claim 7
Dependent Claim
14 words
A process according to claim 5 wherein the system is an evaporative desalination system.
Claim 8
Dependent Claim
15 words
A process according to claim 5 wherein the system is a reverse osmosis desalination system.
Claim 9
Dependent Claim
45 words
A process according to claim 1 wherein at least about 70% of said copolymer has a molecular weight of about 500 to 2,000 and at least about 15% of said copolymer has a molecular weight of about 4,000 to 12,000 on a gel permeation chromatograph.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-06 | 1981-08-08 | 1982-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-06 | 1985-08-08 | 1986-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-06 | 1989-08-08 | 1990-02-07 | $7700.00 | Window Closed / Lapsed |