US4135044A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for achieving high conversions in the production of polyethylene
Assignee: ExxonMobil Technology and Engineering Co
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Filing: 1977-10-11
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Granted: 1979-01-16
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Expires: 1997-10-11
Abstract
Abstract Polyethylene is produced by polymerization of ethylene alone or with comonomers and/or telogens (modifiers) in an elongated tubular reactor having an inlet and outlet and preferably containing four reaction zones. Conversions of up to 40% are achieved without loss of optical or physical product quality.
Inventors
- 👤 Charles D. Beals
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 05:49
CPC Classifications
C; C08; C08F; C08F110/00; C08F110/02
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
116 words
In a process for producing polyethylene in an elongated tubular reactor having an inlet and an outlet, at a pressure of about 20,000 psi to about 60,000 psi comprising passing the reaction mass through a plurality of reaction zones at a flow number of at least about 3.3 ft 2 /sec., each reaction zone followed by a cooling/repreparation zone, and wherein free radical producing substance is injected at the beginning of each reaction zone, the improvement comprising adding at least one additional final reaction zone and cooling zone and decreasing the operating temperatures in the previous reaction zones whereby there is obtained at least a 28% conversion of ethylene to polyethylene while maintaining product haze value.
Claim 2
Dependent Claim
116 words
In a process for producing polyethylene in an elongated tubular reactor having an inlet and an outlet, at a pressure of about 20,000 psi to about 60,000 psi comprising passing the reaction mass through a plurality of reaction zones at a flow number of at least about 3.3 ft 2 /sec., each reaction zone followed by a cooling/repreparation zone, and wherein free radical producing substance is injected at the beginning of each reaction zone, the improvement comprising adding at least one additional final reaction zone and cooling zone and decreasing the operating temperatures in the previous reaction zones whereby there is obtained at least a 28% conversion of ethylene to polyethylene while maintaining product haze value.
Claim 3
Dependent Claim
19 words
The process of claim 1 wherein a sidestream of ethylene is injected into the first and second cooling zones.
Claim 4
Dependent Claim
17 words
The process of claim 1 wherein the operating pressures can be between 25,000 psi and 50,000 psi.
Claim 5
Dependent Claim
36 words
The process of claim 1 wherein the pressure drop across the length of the reactor from the inlet of the first reaction zone to the outlet of the last reaction zone does not exceed 6,000 psi.
Claim 6
Dependent Claim
16 words
The process of claim 1 wherein the flow number is at least 4.0 ft 2 /sec.
Claim 7
Dependent Claim
15 words
The process of claim 1 wherein the haze value is about 3.5 to about 7.5.
Claim 8
Dependent Claim
17 words
The process of claim 1 wherein the decrease in operating temperature range is about 15 to 20%.
Claim 9
Dependent Claim
16 words
The process of claim 2 wherein the tubular reactor comprises four reaction zones and cooling/repreparation zones.
Claim 10
Dependent Claim
17 words
The process of claim 1 wherein the decrease in operating temperature range is about 5 to 30%.
Claim 11
Dependent Claim
25 words
The process of claim 1 wherein the tubular reactor comprises three or four reaction zone and three or four cooling/repreparation zones and no ethylene sidestreams.
Claim 12
Dependent Claim
32 words
The process of claim 1 wherein the tubular reactor comprises three reaction zones and the operating temperature range in the first two reaction zones is reduced by about 40° to 70° F.
Claim 13
Dependent Claim
32 words
The process of claim 1 wherein the tubular reactor comprises four reaction zones and the operating temperature range in the first three reaction zones is reduced by about 60° to 90° F.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-01-15 | 1982-07-17 | 1983-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-01-15 | 1986-07-17 | 1987-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-01-15 | 1990-07-17 | 1991-01-16 | $7700.00 | Window Closed / Lapsed |