US3755264A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Maleic anhydride copolymers and method of making
Assignee: WR Grace and Co Conn
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Filing: 1971-07-30
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Granted: 1973-08-28
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Expires: 1991-07-30
Abstract
Abstract Copolymer of 99 to 85 mol percent of maleic anhydride with from 1 to 15 mol percent of acrylic acid, vinyl acetate, styrene, or mixtures thereof, and hydrolyzed analogous copolymers of maleic acid or maleic salts are highly effective chelating agents. They are made by slowly combining a solution containing the acrylic acid, vinyl acetate, or styrene and a large amount of free radical initiator with a solution containing the maleic anhydride.
Inventors
- 👤 A Testa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:17
CPC Classifications
C; C08; C08F; C08F22/00; C08F22/04; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C08F8/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
14 words
A copolymer as claimed in claim 1 in which said member is acrylic acid.
Claim 2
Dependent Claim
14 words
A copolymer as claimed in claim 1 in which said member is vinyl acetate.
Claim 3
Dependent Claim
13 words
A copolymer as claimed in claim 1 in which said member is styrene.
Claim 4
Dependent Claim
17 words
A copolymer as claimed in claim 1 in which the mol percent is from 85 to 95.
Claim 5
Dependent Claim
119 words
A process for making a copolymer as claimed in claim 1 in which process comprises providing a solution of maleic anhydride in an anhydrous liquid organic solvent, mixing with said solution slowly, over a period of at least 3 hours, a solution containing in an anhydrous liquid organic solvent miscible with said first solvent a free-radical generator and a member of the group consisting of acrylic acid, vinyl acetate, styrene and mixtures thereof, the amount of said free-radical generator being at least 6 percent by weight of the total monomer and the amount of said member being from 1 to 15 mol percent of the total monomer, while maintaining the temperature of said mixed solution at 100* to 145*C.
Claim 6
Dependent Claim
14 words
A process as claimed in claim 6 in which said member is scrylic acid.
Claim 7
Dependent Claim
14 words
A process as claimed in claim 6 in which said member is vinyl acetate.
Claim 8
Dependent Claim
13 words
A process as claimed in claim 6 in which said member is styrene.
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) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |