Patent US3959243A successfully refreshed from Google Patents.
US3959243A
Expired / Lapsed
US
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Method for preparing alpha-olefin polymers
Assignee: Montedison SpA
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Filing: 1970-01-21
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Granted: 1976-05-25
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Expires: 1990-01-21
Abstract
Abstract Stabilizing polypropylene to thermal oxidation and ageing by treating polymeric slurry thereof with aqueous solution of a surfactant. Surfactant is fatty acid ester of condensation product of ethylene oxide and sorbitan.
Inventors
- 👤 Franco Mattioli
- 👤 Oliviero Guanciale, deceased
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 12:16
CPC Classifications
C; C08; C08F; C08F6/00; C08F6/02; Y; Y10; Y10S; Y10S526/00; Y10S526/912
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
113 words
In a method of stabilizing polypropylene, prepared in the presence of a catalyst consisting of at least one organometallic compound of a metal belonging to Groups, I, II or III of the Periodic Table and a solid crystalline halide of a transition metal belonging to Groups IV, V or VI of the Periodic Table, against thermal oxidation and ageing by removing residue of said catalyst from said polypropylene, the improvement which comprises effecting said removal by dispersing in an aqueous slurry of said polypropylene a surfactant selected from the group consisting of polyoxyethylene (20) sorbitan monolaurate, polyoxyethylene (20) sorbitan monopalmitate and polyoxyethylene (20) sorbitan monooleate and thereafter separating the polypropylene from said slurry.
Claim 2
Dependent Claim
113 words
In a method of stabilizing polypropylene, prepared in the presence of a catalyst consisting of at least one organometallic compound of a metal belonging to Groups, I, II or III of the Periodic Table and a solid crystalline halide of a transition metal belonging to Groups IV, V or VI of the Periodic Table, against thermal oxidation and ageing by removing residue of said catalyst from said polypropylene, the improvement which comprises effecting said removal by dispersing in an aqueous slurry of said polypropylene a surfactant selected from the group consisting of polyoxyethylene (20) sorbitan monolaurate, polyoxyethylene (20) sorbitan monopalmitate and polyoxyethylene (20) sorbitan monooleate and thereafter separating the polypropylene from said slurry.
Claim 3
Dependent Claim
43 words
The method of claim 1, wherein said aqueous slurry of polypropylene is obtained by stripping a polymerization slurry thereof to remove the polymerization solvent, said surfactant is then added, and the resulting mixture is then centrifuged and the polypropylene subsequently washed and dried.
Claim 4
Dependent Claim
21 words
The method of claim 1, wherein the relative weight ratio of polypropylene to the surfactant ranges between about 1:0.00025 and 1:0.0025.
Claim 5
Dependent Claim
13 words
The method of claim 1, wherein said surfactant is polyoxyethylene (20) sorbitan monooleate.
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) | 1979-05-25 | 1979-11-24 | 1980-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-25 | 1983-11-24 | 1984-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-25 | 1987-11-24 | 1988-05-25 | $7700.00 | Window Closed / Lapsed |