US4455235A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scale inhibition method employing (meth)acrylic acid/methallylsulfonate copolymer
Assignee: Rhone Poulenc Industries SA
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Filing: 1983-03-11
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Granted: 1984-06-19
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Expires: 2003-03-11
Abstract
Abstract Water-soluble (meth)acrylic acid/methallysulfonate copolymers, containing less than 20% by weight of the methallylsulfonate comonomer, are well suited as scale inhibitors for aqueous environments, especially those comprising essentially equal amounts by weight of both acrylic and methacrylic acids.
Inventors
- 👤 Jean Boutin
- 👤 Jean Neel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:10
CPC Classifications
C; C08; C08F; C08F220/00; C08F220/02; C08F220/04; C08F220/06
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
79 words
A method for inhibiting the formation of scale in an aqueous environment, comprising adding thereto a scale-inhibiting amount of a water-soluble addition copolymer comprising (i) both recurring acrylic acid units and recurring methacrylic acid units, and (ii) a minor amount of recurring alkali metal methallylsulfonate units, the amount by weight of said recurring methallylsulfonate units (ii) in said copolymer being less than 20% of the total amount of said recurring acrylic acid and recurring methacrylic acid units (i) therein.
Claim 2
Independent Claim
79 words
A method for inhibiting the formation of scale in an aqueous environment, comprising adding thereto a scale-inhibiting amount of a water-soluble addition copolymer comprising (i) both recurring acrylic acid units and recurring methacrylic acid units, and (ii) a minor amount of recurring alkali metal methallylsulfonate units, the amount by weight of said recurring methallylsulfonate units (ii) in said copolymer being less than 20% of the total amount of said recurring acrylic acid and recurring methacrylic acid units (i) therein.
Claim 3
Dependent Claim
22 words
The method as defined by claim 1, the amount of copolymer added ranging from 0.2 to 50 mg/liter of said aqueous environment.
Claim 4
Dependent Claim
22 words
The method as defined by claim 2, the amount of copolymer added ranging from 1 to 20 mg/liter of said aqueous environment.
Claim 5
Dependent Claim
41 words
The method as defined by claim 1, the amount by weight of said recurring methallylsulfonate units (ii) in said copolymer ranging from 10 to 18% of the total amount of said recurring acrylic acid and recurring methacrylic acid units (i) therein.
Claim 6
Dependent Claim
19 words
The method as defined by claim 1, said recurring alkali metal methallylsulfonate units (ii) being recurring sodium methallylsulfonate units.
Claim 7
Dependent Claim
23 words
The method as defined by claim 1, said recurring units (i) comprising essentially equal amounts by weight of said acrylic and methacrylic acids.
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) | 1987-06-19 | 1987-12-19 | 1988-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-19 | 1991-12-19 | 1992-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-19 | 1995-12-19 | 1996-06-19 | $7700.00 | Window Closed / Lapsed |