Patent US4762890A successfully refreshed from Google Patents.
US4762890A
Expired / Lapsed
US
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Method of grafting maleic anhydride to polymers
Assignee: Dow Chemical Co
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Filing: 1986-09-05
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Granted: 1988-08-09
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Expires: 2006-09-05
Abstract
Abstract Maleic anhydride can be satisfactorily grafted to polymers at low pressures by feeding the polymer through a co-rotating, twin-screw extruder and injecting the maleic anhydride and a free radical initiator into the extruder. The maleic anhydride and initiator can be pre-mixed in a solvent solution. The solvent and unreacted maleic anhydride can be removed by low pressure devolatilization.
Inventors
- 👤 Chad A. Strait
- 👤 Gerald M. Lancaster
- 👤 Ricky L. Tabor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:26
CPC Classifications
C; C08; C08F; C08F255/00; C08F255/02
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
66 words
A method for grafting maleic anhydride to polymers, comprising the steps of: melting an ethylene polymer by heating and shearing the polymer in a co-rotating, twin-screw extruder; injecting maleic anhydride and a free radical initiator into a polymer filled, pressurized section of the extruder; and mixing the polymer and the maleic anhydride in the extruder for sufficient time to graft the maleic anhydride to the polymer.
Claim 2
Independent Claim
66 words
A method for grafting maleic anhydride to polymers, comprising the steps of: melting an ethylene polymer by heating and shearing the polymer in a co-rotating, twin-screw extruder; injecting maleic anhydride and a free radical initiator into a polymer filled, pressurized section of the extruder; and mixing the polymer and the maleic anhydride in the extruder for sufficient time to graft the maleic anhydride to the polymer.
Claim 3
Dependent Claim
26 words
The method of claim 1, wherein the maleic anhydride and the free radical initiator are mixed in a solvent system prior to injection into the extruder.
Claim 4
Dependent Claim
22 words
The method of claim 1, further comprising the step of devolatilizing the polymer in at least one decompression zone of the extruder.
Claim 5
Dependent Claim
22 words
The method of claim 2, wherein the maleic anhydride and the free radical initiator are mixed within a ketone prior to injection.
Claim 6
Dependent Claim
14 words
The method of claim 4, wherein the polymer is a high density polyethylene resin.
Claim 7
Dependent Claim
12 words
The method of claim 5, wherein the ketone is methyl ethyl ketone.
Claim 8
Dependent Claim
10 words
The method of claim 5, wherein the ketone is acetone.
Claim 9
Dependent Claim
15 words
The method of claim 4, wherein the polymer is a low density copolymer of ethylene/octene.
Claim 10
Dependent Claim
12 words
The method of claim 8, wherein the ketone is methyl ethyl ketone.
Claim 11
Dependent Claim
10 words
The method of claim 8, wherein the ketone is acetone.
Claim 12
Dependent Claim
35 words
The method of claim 1, wherein the extruder predominantly contains right-hand elements, and the polymer filled, pressurized section of the extruder contains a series of mixing type elements that are backed by a left-hand element.
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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) | 1991-08-09 | 1992-02-08 | 1992-08-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-09 | 1996-02-08 | 1996-08-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-09 | 2000-02-08 | 2000-08-09 | $7700.00 | Window Closed / Lapsed |