US4624993A
Expired / Lapsed
US
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Method for depolymerizing polymers
Assignee: MOORE & MUNGER Inc DELAWARE Corp
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Filing: 1985-02-08
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Granted: 1986-11-25
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Expires: 2005-02-08
Abstract
Abstract A method for depolymerizing a non-thermosetting polymer is described. The method comprises the steps of heating the polymer until it is molten and then reacting the molten polymer with oxygen in the absence of a catalyst at a temperature between about 270 DEG F. and about 415 DEG F. by sparging the molten material at a flow rate of at least 2 cubic feet per minute per 1000 pounds of polymer with oxygen-containing gas bubbles having a diameter of less than about 10.0 mm. Advantages of the invention include reduced reaction temperatures, reduced reaction times, elimination of the need for a catalyst, and improved end-products. Treatment of amorphous polypropylene and mixtures of alpha-olefins and Fischer-Tropsch waxes are preferred applications of the invention.
Inventors
- 👤 Janardan D. Upadhyaya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:59
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/50
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
97 words
A method for depolymerizing a meltable, organic polymer wherein said polymer is selected from the group consisting of polyolefins, Fischer-Tropsch waxes, petroleum waxes, and mixtures thereof, comprising the steps of heating the polymer until it is molten and then reacting the molten polymer with oxygen in the absence of a catalyst at a temperature between about 270° F. and about 415° F. by sparging the molten material at a flow rate of at least 2 cubic feet per minute per 1000 pounds of polymer with oxygen-containing gas bubbles having a diameter of less than about 10.0 mm.
Claim 2
Independent Claim
97 words
A method for depolymerizing a meltable, organic polymer wherein said polymer is selected from the group consisting of polyolefins, Fischer-Tropsch waxes, petroleum waxes, and mixtures thereof, comprising the steps of heating the polymer until it is molten and then reacting the molten polymer with oxygen in the absence of a catalyst at a temperature between about 270° F. and about 415° F. by sparging the molten material at a flow rate of at least 2 cubic feet per minute per 1000 pounds of polymer with oxygen-containing gas bubbles having a diameter of less than about 10.0 mm.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein the diameter of the gas bubbles is between about 0.5 mm and about 5.0 mm.
Claim 4
Dependent Claim
24 words
The method of claim 1 wherein the flow rate is between 2 and about 20 cubic feet per minute per 1000 pounds of polymer.
Claim 5
Dependent Claim
19 words
The method of claim 1 wherein the reaction between the molten polymer and oxygen is conducted at atmospheric pressure.
Claim 6
Dependent Claim
30 words
The method of claim 1 wherein the reaction is run at a temperature between about 25° F. and about 50° F. above the melting point of the polymer being depolymerized.
Claim 7
Dependent Claim
11 words
The method of claim 1 wherein the oxygen-containing gas is air.
Claim 8
Dependent Claim
19 words
The method of claim 1 including the additional step of stirring the molten polymer while it is being sparged.
Claim 9
Dependent Claim
56 words
The method of claim 1 wherein the polymer is amorphous polypropylene, the reaction is conducted at a temperature between about 385° F. and about 405° F., the oxygen-containing gas is air, and the depolymerized polymer has a viscosity at 347° F. of between about 100 and 250 centipoise and a softening point of below 267° F.
Claim 10
Dependent Claim
39 words
The method of claim 1 wherein the polymer is a mixture of a polyolefin prepared from an alpha-olefin and a Fischer-Tropsch wax, the reaction is conducted at a temperature below about 347° F., and the oxygen-containing gas is air.
Claim 11
Dependent Claim
12 words
The method of claim 9 wherein the alpha-olefin is C 30+ alpha-olefin.
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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) | 1989-11-24 | 1990-05-26 | 1990-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-11-24 | 1994-05-26 | 1994-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-11-24 | 1998-05-26 | 1998-11-25 | $7700.00 | Window Closed / Lapsed |