US3719648A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the preparation of powdery homo-or copolymers of ethylene
Assignee: Stamicarbon BV
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Filing: 1971-06-23
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Granted: 1973-03-06
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Expires: 1991-06-23
Abstract
Abstract A process for the recovery of powdery homopolymers or copolymers of ethylene from a polymerization system is disclosed, wherein the corresponding monomers are subjected to polymerization conditions in a reactor and the resulting polymer, together with unconverted monomer, is discharged from the reactor and expanded to a lower pressure. At least part of this mixture is quenched by the addition of a cold gas, which gas is at least one of the polymerization monomers, to a temperature below the melting point of the polymer to solidify the polymer contained in such mixture as the form of a fine powder. Thereafter the powder is separated from the mixture and remaining unconverted monomer is recycled to the reactor. The process involves simpler equipment and reduced utility costs as compared to prior processes.
Inventors
- 👤 J Frielink
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:22
CPC Classifications
C; C08; C08F; C08F10/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
151 words
In a process for the preparation of powdery homopolymers or copolymers of ethylene, wherein (a) monomer, consisting of ethylene and 0 - 50 mole percent of at least one other unsaturated organic compound copolymerizable therewith, is subjected to elevated temperature and elevated pressure in a reactor in the presence of a polymerization initiator, (b) the resulting liquid polymer, together with unconverted monomer, is discharged from the reactor and expanded to a lower pressure, (c) the expanded mixture, at least in part, is quenched by the addition of a cold medium to solidify polymer contained in said mixture to a fine powder, (d) thereafter the powder is separated from the mixture, and (e) the remaining monomer is compressed to substantially said elevated pressure and returned to the reactor, the improvement comprising quenching said expanded mixture with a cold gas which consists essentially of at least one of the monomers to be polymerized.
Claim 2
Dependent Claim
151 words
In a process for the preparation of powdery homopolymers or copolymers of ethylene, wherein (a) monomer, consisting of ethylene and 0 - 50 mole percent of at least one other unsaturated organic compound copolymerizable therewith, is subjected to elevated temperature and elevated pressure in a reactor in the presence of a polymerization initiator, (b) the resulting liquid polymer, together with unconverted monomer, is discharged from the reactor and expanded to a lower pressure, (c) the expanded mixture, at least in part, is quenched by the addition of a cold medium to solidify polymer contained in said mixture to a fine powder, (d) thereafter the powder is separated from the mixture, and (e) the remaining monomer is compressed to substantially said elevated pressure and returned to the reactor, the improvement comprising quenching said expanded mixture with a cold gas which consists essentially of at least one of the monomers to be polymerized.
Claim 3
Dependent Claim
28 words
The process as claimed in claim 1, wherein the mixture of polymer and unconverted monomer discharged from the reactor is expanded to at least 100 times its volume.
Claim 4
Dependent Claim
28 words
The process as claimed in claim 1, wherein said elevated temperature is about 120* to about 400*C, and said elevated pressure is about 500 to about 5,000 atmospheres.
Claim 5
Dependent Claim
28 words
The process as claimed in claim 1, wherein said other unsaturated organic compound is selected from the group consisting of unsaturated esters, alkene compounds, acrylonitrile and vinyl chloride.
Claim 6
Dependent Claim
32 words
The process as claimed in claim 1, including the step of adding from 0.5 to 10 mole percent, based on the amount of ethylene, of a chain transfer agent to said reactor.
Claim 7
Dependent Claim
46 words
The process as claimed in claim 1, wherein the temperature of the mixture of polymer and unconverted monomer discharged from the reactor is reduced, before or during the expansion, by external cooling to a temperature from 10* to 40*C above the melting point of the polymer.
Claim 8
Dependent Claim
28 words
The process as claimed in claim 1, wherein the amount of said cold gas is at least equal to the amount of the monomer polymerized in said reactor.
Claim 9
Dependent Claim
90 words
The process as claimed in claim 7, wherein an excess quantity of cold monomer is introduced into the mixture of monomer and polymer discharged from the reactor, and the unconverted monomer remaining after the polymer has been removed is divided into a portion which is returned to the reactor and a second portion which, after having been admixed with a quantity of fresh monomer corresponding to the amount of monomer converted into polymer, is cooled and again used to quench the mixture of polymer and monomer discharged from the reactor.
Claim 10
Dependent Claim
88 words
The process as claimed in claim 1, wherein the mixture of polymer and monomer discharged from the reactor divided into a part which is expanded and from which the polymer is separated in the liquid state and into a second part which is expanded and is thereafter quenched with cold monomer, said second part being in an amount such that a quantity of monomer corresponding to the amount of monomer converted into polymer will cause the second part to be cooled below the melting point of said polymer.
Claim 11
Dependent Claim
25 words
The process as claimed in claim 1, wherein the temperature of said cold gas is at least 80*C below the melting point of the polymer.
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) | 1976-03-05 | 1976-09-04 | 1977-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-05 | 1980-09-04 | 1981-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-05 | 1984-09-04 | 1985-03-06 | $7700.00 | Window Closed / Lapsed |