US4029877A
Expired / Lapsed
US
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Process for preparing polyolefin
Assignee: Mitsubishi Chemical Corp
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Filing: 1975-06-10
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Granted: 1977-06-14
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Expires: 1995-06-10
Abstract
Abstract In a process for preparing a polyolefin without separation of catalyst residues by polymerizing an olefin in the pres ence of a Ziegler catalyst having high catalytic activity, in an inert gas sealing system; an improvement comprises separating the polyolefin containing the catalyst residue from the polymerization mixture, and contacting the polyolefin containing the catalyst residue with a weak reactive gas of oxygen and/or steam diluted with an inert gas.
Inventors
- 👤 Hirohisa Yoshiura
- 👤 Toshiharu Arai
- 👤 Masao Miyake
- 👤 Yoshikane Furuya
- 👤 Seiji Onogi
- 👤 Tetsushi Kamizono
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:04
CPC Classifications
C; C08; C08F; C08F6/00; C08F6/02; C08F8/00; C08F8/50; C08F2810/00; C08F2810/10
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
114 words
In a process for preparing a polyolefin by polymerizing an olefin in the presence of a Ziegler catalyst having high catalytic activity, in an inert gas sealing system, the improvement which consists essentially of: separating the polyolefin containing the catalyst residue from the polymerization mixture; and contacting the polyolefin containing the catalyst residue with a weakly reactive gas of a mixture of an inert gas and a component selected from the group consisting of oxygen, water vapor and mixtures thereof, wherein the concentration of oxygen and water vapor in the inert gas ranges from 0.05 to 0.5 mole percent and 0.05 to 1 mole percent respectively, without separation of catalyst residues from said polyolefin.
Claim 2
Dependent Claim
114 words
In a process for preparing a polyolefin by polymerizing an olefin in the presence of a Ziegler catalyst having high catalytic activity, in an inert gas sealing system, the improvement which consists essentially of: separating the polyolefin containing the catalyst residue from the polymerization mixture; and contacting the polyolefin containing the catalyst residue with a weakly reactive gas of a mixture of an inert gas and a component selected from the group consisting of oxygen, water vapor and mixtures thereof, wherein the concentration of oxygen and water vapor in the inert gas ranges from 0.05 to 0.5 mole percent and 0.05 to 1 mole percent respectively, without separation of catalyst residues from said polyolefin.
Claim 3
Dependent Claim
27 words
The process of claim 1, wherein a powdery or granular polyolefin is contacted with said weakly reactive gas at a temperature from 40° C to 110° C.
Claim 4
Dependent Claim
21 words
The process of claim 1, wherein a molten or semimolten polyolefin is contacted with said weakly reactive gas at 150°-300° C.
Claim 5
Dependent Claim
20 words
The process of claim 1, wherein the polyolefin is contacted with the weakly reactive gas before the polyolefin is melted.
Claim 6
Dependent Claim
26 words
The process of claim 1, wherein the polyolefin is contacted with the weakly reactive gas in a two step pelletizing operation, or in a drying operation.
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) | 1980-06-13 | 1980-12-13 | 1981-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-13 | 1984-12-13 | 1985-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-13 | 1988-12-13 | 1989-06-14 | $7700.00 | Window Closed / Lapsed |