US3933747A
Expired / Lapsed
US
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Reversible cross-linking of maleic anhydride copolymers
Assignee: Dow Chemical Co
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Filing: 1971-04-02
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Granted: 1976-01-20
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Expires: 1991-04-02
Abstract
Abstract Copolymers containing from 5 to 25 mole percent of anhydride, such as maleic anhydride, have improved, thermally induced reversible cross-linking characteristics when the crosslinking agent is selected from certain hydroxyl containing derivatives of bisphenol A.
Inventors
- 👤 Robert M. Nowak
- 👤 Kenneth J. Guilette
- 👤 Eugene R. Moore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:17
CPC Classifications
C; C08; C08K; C08K5/00; C08K5/04; C08K5/05; C08K5/053; C08K5/06; C08K5/49; C08K5/51; C08K5/53
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
153 words
In a process for thermally reversing cross-links in a cross-linked composition by heating to about 175° to 300°C. and then cooling to reform a cross-linked composition wherein said composition comprises an intimate mixture of a vinyl interpolymer having reactive anhydride groups and a polyfunctional cross-linking agent, the improvement which comprises employing a cross-linking agent selected from the group consisting of hydrogenated 4,4'-isopropylidene diphenol, hydroxyalkyl diethers of 4,4'-isopropylidene diphenol and hydroxyalkyl diethers of hydrogenated 4,4'-isopropylidene diphenol wherein said hydroxyalkyl ether group in each case contains from 2 to 4 carbon atoms, employing a vinyl copolymer having from about 5 to 25 mole percent of an unsaturated dicarboxylic acid anhydride and employing a catalytic amount of a monoalkyl or a dialkyl phosphoric acid wherein the alkyl group contains from about 5 to 18 carbon atoms; said cross-linking agent present in an amount to provide about 0.05 to 0.5 moles of hydroxyl per mole of anhydride.
Claim 2
Dependent Claim
153 words
In a process for thermally reversing cross-links in a cross-linked composition by heating to about 175° to 300°C. and then cooling to reform a cross-linked composition wherein said composition comprises an intimate mixture of a vinyl interpolymer having reactive anhydride groups and a polyfunctional cross-linking agent, the improvement which comprises employing a cross-linking agent selected from the group consisting of hydrogenated 4,4'-isopropylidene diphenol, hydroxyalkyl diethers of 4,4'-isopropylidene diphenol and hydroxyalkyl diethers of hydrogenated 4,4'-isopropylidene diphenol wherein said hydroxyalkyl ether group in each case contains from 2 to 4 carbon atoms, employing a vinyl copolymer having from about 5 to 25 mole percent of an unsaturated dicarboxylic acid anhydride and employing a catalytic amount of a monoalkyl or a dialkyl phosphoric acid wherein the alkyl group contains from about 5 to 18 carbon atoms; said cross-linking agent present in an amount to provide about 0.05 to 0.5 moles of hydroxyl per mole of anhydride.
Claim 3
Dependent Claim
11 words
The process of claim 1 wherein said anhydride is maleic anhydride.
Claim 4
Dependent Claim
17 words
The process of claim 1 wherein said vinyl copolymer is a copolymer of styrene and maleic anhydride.
Claim 5
Dependent Claim
11 words
The process of claim 1 wherein the catalyst is di-(2-ethylhexyl)phosphoric acid.
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) | 1979-01-19 | 1979-07-21 | 1980-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-19 | 1983-07-21 | 1984-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-19 | 1987-07-21 | 1988-01-20 | $7700.00 | Window Closed / Lapsed |