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US4175100A Expired / Lapsed US ⏱️ 0.0 years remaining

Preparation of anionic polymers for use as scale inhibitors and anti-precipitants

Assignee: Wyeth Holdings LLC
•
Filing: 1977-12-22
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Granted: 1979-11-20
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Expires: 1997-12-22
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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 M. Schiller
  • 👤 Richard M. Goodman
  • 👤 Roger E. Neff

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-23 14:44
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: 6
Claim 1
Independent Claim 93 words
A composition of matter consisting essentially of a blend of copolymers of from about 95 to 50 mol percent acrylic acid and, correspondingly, about 5 to 50 mol percent acrylamide, said copolymers consisting of a skewed molecular weight distribution such that on a gel permeation chromatograph at least about 60% of said copolymers have a molecular weight of about 500 to 2,000, at least about 10% of said copolymers have a molecular weight of about 4,000 to 12,000 and any balance of said copolymers have a molecular weight of about 500 to 12,000.
Claim 2
Dependent Claim 93 words
A composition of matter consisting essentially of a blend of copolymers of from about 95 to 50 mol percent acrylic acid and, correspondingly, about 5 to 50 mol percent acrylamide, said copolymers consisting of a skewed molecular weight distribution such that on a gel permeation chromatograph at least about 60% of said copolymers have a molecular weight of about 500 to 2,000, at least about 10% of said copolymers have a molecular weight of about 4,000 to 12,000 and any balance of said copolymers have a molecular weight of about 500 to 12,000.
Claim 3
Dependent Claim 29 words
A composition described in claim 1 wherein the blend is composed of copolymers of acrylic acid and acrylamide linkages in the mol ratios of about 20:1 to about 1:1.
Claim 4
Dependent Claim 17 words
A composition described in claim 2 wherein the acrylic acid linkage is neutralized to an acrylate salt.
Claim 5
Dependent Claim 13 words
A composition described in claim 3 wherein the acrylate salt is sodium acrylate.
Claim 6
Dependent Claim 46 words
A composition described in claim 1 wherein at least about 70% of said blend consists of copolymers having a molecular weight of about 500 to 2,000 and at least about 15% of said blend consists of copolymers having a molecular weight of about 4,000 to 12,000.

References Cited (Backward Citations)

US2886558A Cited
US3573263A Cited
US3493500A Cited
US3839500A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1982-11-19 1983-05-21 1983-11-20 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1986-11-19 1987-05-21 1987-11-20 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1990-11-19 1991-05-21 1991-11-20 $7700.00 Window Closed / Lapsed

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