US4246398A
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Method for recovering polyphenylene oxides
Assignee: Mitsubishi Gas Chemical Co Inc
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Filing: 1979-05-02
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Granted: 1981-01-20
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Expires: 1999-05-02
Abstract
Abstract A method for recovering polyphenylene oxide having a high bulk density and a reduced content of fine particles from a solution of a polyphenylene oxide, which comprises adding a non-solvent composed of a lower alkyl alcohol and water to an aromatic solvent solution of a polyphenylene oxide substantially free from impurities to precipitate the polyphenylene oxide, the weight ratio of the aromatic solvent to the lower alkyl alcohol being from 1:1 to 1:2 and the weight ratio of the lower alkyl alcohol to water being from 1:0.005 to 1:0.1 in the precipitation system, and the addition of the non-solvent being controlled such that a liquid composition of the aromatic solvent, the lower alkyl alcohol and water forms a single phase; and recovering the precipitated polyphenylene oxide.
Inventors
- 👤 Akitoshi Sugio
- 👤 Atsuo Kuramoto
- 👤 Takao Kawaki
- 👤 Hiroyuki Urabe
- 👤 Tatsuhiko Kurihara
- 👤 Isamu Masumoto
- 👤 Akio Hasebe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:02
CPC Classifications
C; C08; C08G; C08G65/00; C08G65/34; C08G65/46
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
126 words
A method for recovering polyphenylene oxide having a high bulk density and a reduced content of fine particles from a solution of a polyphenylene oxide, which comprises adding a non-solvent composed of a lower alkyl alcohol and water to an aromatic solvent solution of a polyphenylene oxide substantially free from impurities to precipitate the polyphenylene oxide, the weight ratio of the aromatic solvent to the lower alkyl alcohol being from 1:1 to 1:2 and the weight ratio of the lower alkyl alcohol to water being from 1:0.005 to 1:0.1 in the precipitation system, and the addition of the non-solvent being controlled such that a liquid composition of the aromatic solvent, the lower alkyl alcohol and water forms a single phase; and recovering the precipitated polyphenylene oxide.
Claim 2
Independent Claim
126 words
A method for recovering polyphenylene oxide having a high bulk density and a reduced content of fine particles from a solution of a polyphenylene oxide, which comprises adding a non-solvent composed of a lower alkyl alcohol and water to an aromatic solvent solution of a polyphenylene oxide substantially free from impurities to precipitate the polyphenylene oxide, the weight ratio of the aromatic solvent to the lower alkyl alcohol being from 1:1 to 1:2 and the weight ratio of the lower alkyl alcohol to water being from 1:0.005 to 1:0.1 in the precipitation system, and the addition of the non-solvent being controlled such that a liquid composition of the aromatic solvent, the lower alkyl alcohol and water forms a single phase; and recovering the precipitated polyphenylene oxide.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein the aromatic solvent is at least one member selected from the group consisting of benzene, toluene and xylene.
Claim 4
Dependent Claim
11 words
The method of claim 2 wherein the aromatic solvent is toluene.
Claim 5
Dependent Claim
25 words
The method of claim 1 wherein the lower alkyl alcohol is at least one member selected from the group consisting of methanol, ethanol and isopropanol.
Claim 6
Dependent Claim
12 words
The method of claim 4 wherein the lower alkyl alcohol is methanol.
Claim 7
Dependent Claim
151 words
The method of claim 1 wherein the polyphenylene oxide comprises a structural unit of the following formula ##STR2## wherein n is an integer of at least 50, R 1 represents a monovalent substituent selected from the group consisting of a hydrogen atom, alkyl groups having 1 to 5 carbon atoms, haloalkyl groups having 1 to 5 carbon atoms with at least two carbon atoms present between the halogen and the phenyl nucleus, alkoxy groups having 1 to 5 carbon atoms and haloalkoxy groups having 1 to 5 carbon atoms with at least two carbon atoms between the halogen and the phenyl nucleus, and R 2 , R 3 and R 4 are the same as R 1 or represent a halogen atom, with the proviso that R 1 , R 2 , R 3 and R 4 do not represent substituents in which the α-carbon atom is a tertiary carbon atom.
Claim 8
Dependent Claim
23 words
The method of claim 6 wherein R 1 and R 2 are methyl groups, and R 3 and R 4 are hydrogen atoms.
Claim 9
Dependent Claim
65 words
The method of claim 6 wherein the polyphenylene oxide is a polyphenylene oxide copolymer containing a unit of the formula in which R 1 and R 2 are methyl groups and R 3 , R 4 are hydrogen atoms and a unit of the formula in which R 1 , R 2 and R 3 are methyl groups and R 4 is a hydrogen atom.
Claim 10
Dependent Claim
26 words
The method of claim 1 wherein the polyphenylene oxide solution, the lower alcohol and water are continuously added, and the precipitated polyphenylene oxide is withdrawn continuously.
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) | 1984-01-20 | 1984-07-21 | 1985-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-20 | 1988-07-21 | 1989-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-20 | 1992-07-21 | 1993-01-20 | $7700.00 | Window Closed / Lapsed |