US3714137A
Expired / Lapsed
US
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PROCESS FOR THE PRODUCTION OF POLYVINYLIDENE FLUORIDE IN THE PRESENCE OF A PEROXYDISULFATE INITIATOR AT AN ACIDIC pH
Assignee: SUEDDEUTSCHE KALKSTICKSTOFF WERKE AG DT
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Filing: 1970-07-31
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Granted: 1973-01-30
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Expires: 1990-07-31
Abstract
Abstract Vinylidene fluoride is polymerized in an acidic aqueous medium in the presence of a peroxide disulfate polymerization initiator in a concentration of less than 0.5 gram/liter of the liquid reaction phase.
Inventors
- 👤 K Lienhard
- 👤 D Ulmschneider
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 02:15
CPC Classifications
C; C08; C08F; C08F14/00; C08F14/18; C08F14/22
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
83 words
A process of preparing polyvinylidene fluoride consisting of polymerizing vinylidene fluoride in an aqueous reaction medium at an elevated pressure and elevated temperature in the presence of a peroxydisulfate polymerization initiator in a concentration of between (i) less than 0.5 gram/liter and (ii) 0.0005 gram/liter of the aqueous reaction phase, the polymerization being carried out at an acidic pH, said acidic pH being obtained by the addition of an acid selected from the group consisting of boric acid, sulfuric acid and hydrochloric acid.
Claim 2
Dependent Claim
83 words
A process of preparing polyvinylidene fluoride consisting of polymerizing vinylidene fluoride in an aqueous reaction medium at an elevated pressure and elevated temperature in the presence of a peroxydisulfate polymerization initiator in a concentration of between (i) less than 0.5 gram/liter and (ii) 0.0005 gram/liter of the aqueous reaction phase, the polymerization being carried out at an acidic pH, said acidic pH being obtained by the addition of an acid selected from the group consisting of boric acid, sulfuric acid and hydrochloric acid.
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein the pH is between 4 and 6.
Claim 4
Dependent Claim
15 words
The process of claim 1 wherein the initiator concentration is between 0.03 and 0.2 gram/liter.
Claim 5
Dependent Claim
20 words
The process of claim 1 wherein the initiator is selected from the group consisting of ammonium peroxydisulfate and potassium peroxydisulfate.
References Cited (Backward Citations)
US2435537A
Cited
US3031437A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-30 | 1976-07-31 | 1977-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-30 | 1980-07-31 | 1981-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-30 | 1984-07-31 | 1985-01-30 | $7700.00 | Window Closed / Lapsed |