US4051313A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for purifying polypropylene
Assignee: Montedison SpA
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Filing: 1975-10-29
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Granted: 1977-09-27
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Expires: 1995-10-29
Abstract
Abstract Polypropylene obtained by polymerizing propylene in contact with stereospecific catalysts supported on anhydrous magnesium dihalides is purified, and the magnesium content thereof is reduced, by treating a suspension of the polypropylene in a hydrocarbon solvent with an aliphatic alcohol containing from 3 to 8 carbon atoms, followed by centrifuging to remove both the hydrocarbon solvent and the catalyst residues solubilized by the alcohol treatment.
Inventors
- 👤 Luciano Luciani
- 👤 Gianni Nava
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:25
CPC Classifications
C; C08; C08F; C08F6/00; C08F6/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
141 words
A process for practically completely removing magnesium dihalide from a polypropylene obtained by polymerizing propylene in contact with a catalyst prepared by mixing (A) an aluminum trialkyl partially complexed with an electron-donor compound with (B) a titanium tri- or tetra-halide supported on an anhydrous magnesium dihalide, or a complex of a titanium tri- or tetra-halide with an electron donor compound supported on an anhydrous magnesium dihalide, and which polypropylene contains catalyst residues including magnesium dihalide, said process comprising mixing an aliphatic alcohol containing from 3 to 8 carbon atoms with a suspension of the polypropylene in a hydrocarbon solvent at a temperature of from 60° C to 100° C to thereby solubilize catalyst residues present in the polypropylene, including the magnesium halide, and thereafter separating both the solvent and the solubilized catalyst residues including the solubilized magnesium dihalide, from the polypropylene.
Claim 2
Dependent Claim
141 words
A process for practically completely removing magnesium dihalide from a polypropylene obtained by polymerizing propylene in contact with a catalyst prepared by mixing (A) an aluminum trialkyl partially complexed with an electron-donor compound with (B) a titanium tri- or tetra-halide supported on an anhydrous magnesium dihalide, or a complex of a titanium tri- or tetra-halide with an electron donor compound supported on an anhydrous magnesium dihalide, and which polypropylene contains catalyst residues including magnesium dihalide, said process comprising mixing an aliphatic alcohol containing from 3 to 8 carbon atoms with a suspension of the polypropylene in a hydrocarbon solvent at a temperature of from 60° C to 100° C to thereby solubilize catalyst residues present in the polypropylene, including the magnesium halide, and thereafter separating both the solvent and the solubilized catalyst residues including the solubilized magnesium dihalide, from the polypropylene.
Claim 3
Dependent Claim
22 words
The process according to claim 1, in which the solvent and the solubilized catalyst residues are separated from the polypropylene by centrifuging.
Claim 4
Dependent Claim
33 words
The process according to claim 1, in which the propylene is polymerized in an inert hydrocarbon solvent and the resulting slurry comprising polypropylene withdrawn from the polymerization reactor is treated with the alcohol.
Claim 5
Dependent Claim
39 words
The process of claim 1, in which the aliphatic alcohol is used in an amount of from 1 to 10% by volume, based on the volume of the hydrocarbon solvent in which the polymerizate to be purified is suspended.
Claim 6
Dependent Claim
13 words
The process according to claim 1, in which the aliphatic alcohol is isopropanol.
Claim 7
Dependent Claim
13 words
The process according to claim 1, in which the aliphatic alcohol is n-butanol.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-09-26 | 1981-03-28 | 1981-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-26 | 1985-03-28 | 1985-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-26 | 1989-03-28 | 1989-09-27 | $7700.00 | Window Closed / Lapsed |