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US4532046A
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Method for hindering the scaling by waters
Assignee: NATIONALE ELF AQUITAINE TOUR AQUITAINE TOUR AQUITAINE Ste
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Filing: 1983-08-24
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Granted: 1985-07-30
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Expires: 2003-08-24
Abstract
Abstract A method for eliminating the scaling by deposit of alkaline earth compounds from an aqueous medium; to said medium is added an agent comprising a water-soluble polymer bearer of hydroxamic groups attached to a linear hydrocarbon chain.
Inventors
- 👤 Gilles Meunier
- 👤 Lino Vio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:07
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/12
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
158 words
A method of hindering the scaling of surfaces through the deposition thereon of alkaline earth compounds from a water containing the same, which comprises dissolving in the water a scale inhibiting amount of a member selected from the group of: (a) a hydroxamic group bearing homopolymer having a molecular weight between 800 and 20,000, said hydroxamic group attached to a linear polyolefinic hydrocarbon chain, and (b) a hydroxamic group bearing copolymer, said hydroxamic group being attached to a linear polyolefinic hydrocarbon chain which is a copolymer with functional groups selected from the group consisting of acrylic acid, an acrylic ester, a salt of acrylic acid, maleic acid, a maleic ester, a salt of maleic acid, vinyl acetate, vinyl pyrrolidone, butadiene, styrene, and acrylonitrile, the proportions of hydroxamic groups to other functional groups being from 15 to 85 of the total of said hydroxamic and other functional groups, and said copolymer having a molecular weight between 800 and 7500.
Claim 2
Independent Claim
158 words
A method of hindering the scaling of surfaces through the deposition thereon of alkaline earth compounds from a water containing the same, which comprises dissolving in the water a scale inhibiting amount of a member selected from the group of: (a) a hydroxamic group bearing homopolymer having a molecular weight between 800 and 20,000, said hydroxamic group attached to a linear polyolefinic hydrocarbon chain, and (b) a hydroxamic group bearing copolymer, said hydroxamic group being attached to a linear polyolefinic hydrocarbon chain which is a copolymer with functional groups selected from the group consisting of acrylic acid, an acrylic ester, a salt of acrylic acid, maleic acid, a maleic ester, a salt of maleic acid, vinyl acetate, vinyl pyrrolidone, butadiene, styrene, and acrylonitrile, the proportions of hydroxamic groups to other functional groups being from 15 to 85 of the total of said hydroxamic and other functional groups, and said copolymer having a molecular weight between 800 and 7500.
Claim 3
Dependent Claim
21 words
The method according to claim 1, wherein said hydrocarbon chain is selected from the group consisting of polyvinylic, polyacrylic and polybutenylic.
Claim 4
Dependent Claim
33 words
A method according to claim 1, wherein said linear hydrocarbon chain, which bears hydroxamic groups, comprises a copolymer of the hydrocarbon with acrylic acid, an acrylic ester or a salt of acrylic acid.
Claim 5
Dependent Claim
33 words
A method according to claim 1, wherein said linear hydrocarbon chain which bears hydroxamic groups, comprises a copolymer of the hydrocarbon with maleic acid, a maleic ester or a salt of maleic acid.
Claim 6
Dependent Claim
37 words
A method according to claim 1, wherein said linear hydrocarbon chain which bears hydroxamic groups, comprises a copolymer of the hydrocarbon with units selected from the group consisting of vinyl acetate, vinyl pyrrolidone, butadiene, styrene and acrylonitrile.
Claim 7
Dependent Claim
26 words
A method according to claim 1, wherein at least one of the oxygen atoms in the hydroxamic functional group ##STR5## is replaced by a sulfur atom.
Claim 8
Dependent Claim
24 words
A method according to claim 1, wherein the concentration of the hydroxamic group bearing polymer is 1 to 50 mg per liter of water.
Claim 9
Dependent Claim
32 words
A method according to claim 1, wherein one or two hydrogen atoms in the --NHOH moiety of the hydroxamic group is substituted with C 1 to C 6 alkyl, phenyl or alkylaryls.
Claim 10
Independent Claim
81 words
A method of hindering the scaling of surfaces in contact with a water which contains calcium compounds, barium compounds or calcium and barium compounds, through the deposition thereon of said compounds from the water, which comprises dissolving in the water 1 to 50 mg per liter of a polymer comprising polyacrylamide in which 15 to 85% of the amide groups are replaced by hydroxamic groups of the formula ##STR6## the molecular weight of the polymer being comprised between 1,000 and 20,000.
Claim 11
Independent Claim
81 words
A method of hindering the scaling of surfaces in contact with a water which contains calcium compounds, barium compounds or calcium and barium compounds, through the deposition thereon of said compounds from the water, which comprises dissolving in the water 1 to 50 mg per liter of a polymer comprising polyacrylamide in which 15 to 85% of the amide groups are replaced by hydroxamic groups of the formula ##STR6## the molecular weight of the polymer being comprised between 1,000 and 20,000.
Claim 12
Dependent Claim
26 words
A method according to claim 9, wherein said polymer comprises a polyacrylamide in which 15 to 70% of the amide groups are replaced by hydroxamic groups.
Claim 13
Dependent Claim
26 words
A method according to claim 10, wherein at least one of the oxygen atoms in the hydroxamic functional group ##STR7## is replaced by a sulfur atom.
Claim 14
Dependent Claim
18 words
A method according to claim 10, wherein the degree of polymerisation in the polymer is 5 to 600.
Claim 15
Dependent Claim
23 words
A method according to claim 10, wherein the concentration of the polymer in the water treated is 0.5 to 10 mg per liter.
Claim 16
Dependent Claim
28 words
A method according to claim 12, wherein 2 to 5 mg of polymer is added to the water to be treated per 100 mg of Calcium present therein.
Claim 17
Dependent Claim
14 words
A method according to claim 9, wherein the molecular weight is 1,200 to 12,000.
Claim 18
Dependent Claim
12 words
A method according to claim 9, wherein the water is sea water.
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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) | 1988-07-29 | 1989-01-28 | 1989-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-29 | 1993-01-28 | 1993-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-29 | 1997-01-28 | 1997-07-30 | $7700.00 | Window Closed / Lapsed |