Patent US3661881A successfully refreshed from Google Patents.
US3661881A
Expired / Lapsed
US
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Process for preparing vinyl chloride polymers of reduced porosity
Assignee: Dow Chemical Co
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Filing: 1970-09-03
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Granted: 1972-05-09
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Expires: 1990-09-03
Abstract
Abstract THIS INVENTION IS DIRECTED TO A PROCESS FOR PREPARING VINYL CHLORIDE POLYMER OF REDUCED POROSITY IN AQUEOUS SUSPENSION WHILE IN THE PRESENCE OF A MONOMER-SOLUBLE POLYMERIZATION CATALYST AND WHILE MAINTAINING AN ESSENTIALLY CONSTANT REACTION TEMPERATURE. MORE PARTICULARLY, THE POLYMERIZATION REACTION IS CONTINUED UNTIL A DECREASE OR FROM ABOUT 1 TO 20 P.S.I. FROM THE LIQUID-VAPOR EQUILIBRIUM PRESSURE OF THE REACTION OCCURS. THEREAFTER, THE REDUCED PRESSURE IS MAINTAINED BY THE ADDITION OF MONOMER AND POLYMERIZING OF THE SAME IN CONTACT WITH THE PREVIOUSLY FORMED POLYMER UNTIL A POLYMER PRODUCT OF LOWER POROSITY IS OBTAINED.
Inventors
- 👤 Donald E Moore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:45
CPC Classifications
C; C08; C08F; C08F14/00; C08F14/02; C08F14/04; C08F14/06
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-09 | 1975-11-08 | 1976-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-09 | 1979-11-08 | 1980-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-09 | 1983-11-08 | 1984-05-09 | $7700.00 | Window Closed / Lapsed |