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US4075171A
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Process for preparing aromatic polyimides and some polyimides prepared thereby
Assignee: University of Notre Dame
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Filing: 1974-12-16
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Granted: 1978-02-21
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Expires: 1994-12-16
Abstract
Abstract A process for preparing substantially completely cyclized aromatic polyimides, either monomeric, oligomeric or polymeric, is provided. The process involved the reaction of a mixture of at least one tetracarboxylic acid dianhydride, at least one aromatic diamine and an α,β-carboxylic acid monoanhydride in at least one aromatic phenol, preferably cresols, in the presence of an organic azeotroping agent such as a cyclic hydrocarbon, preferably benzene, until substantially all of the water of reaction is eliminated. The monoanhydride provides reactive end groups which will enable the polyimide to cure by coupling together by addition or condensation thereby increasing molecular weight with little or no by-product. After the water is removed, it is preferred that the azeotroping agent be removed and then the polyimide increased in molecular weight by heating in the aromatic phenol. The polymer can then be isolated by concentration or precipitation as a powder, or the polymer in solution can be used to prepare coatings on various substrates.
Inventors
- 👤 Gaetano F. D'Alelio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:45
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1057; C08G73/1003; C08G73/1007; C08G73/101; C08G73/106; C08G73/1064; C08G73/1067; C08G73/1071; Y; Y10; Y10S; Y10S525/00; Y10S525/925; Y10S525/928; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31721
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
74 words
A process for the preparation of a substantially cyclized polyimide of the formula: ##STR18## wherein Ar is a divalent aromatic organic radical, Ar' is a tetravalent aromatic organic radical, the four carbonyl groups being attached directly to separate carbon atoms and each pair of carbonyl groups being attached to adjacent carbon atoms in the Ar' radical, ##STR19## n is 0 or a positive integer of at least one, soluble in a phenol which comprises:
Claim 2
Dependent Claim
74 words
A process for the preparation of a substantially cyclized polyimide of the formula: ##STR18## wherein Ar is a divalent aromatic organic radical, Ar' is a tetravalent aromatic organic radical, the four carbonyl groups being attached directly to separate carbon atoms and each pair of carbonyl groups being attached to adjacent carbon atoms in the Ar' radical, ##STR19## n is 0 or a positive integer of at least one, soluble in a phenol which comprises:
Claim 3
Dependent Claim
199 words
reacting a reaction mixture of at least one tetracarboxylic acid dianhydride of the formula: ##STR20## wherein Ar' is as defined above, and at least one aromatic diamine of the formula: C. H.sub.2 N--AR--NH.sub.2 wherein Ar is as defined above, at a molar ratio of dianhydride to diamine of m to m + 1 where m is zero or a positive integer of at least one and as high as n in formula (A), with the proviso that the reaction mixture contains 2 moles of an α,β-carboxylic acid monoanhydride of the formula ##STR21## in a phenol of the formula ##STR22## where each R' is hydrogen or --CH 3 in the presence of at least one organic azeotroping agent which: a. gives a water azeotrope having a boiling point less than 95° C at atmospheric pressure, b. is non-reactive with the dianhydride and the diamine, and c. separates from water as a distinct phase, said reaction conducted at a temperature less than 140° C and below the boiling point of said phenol and higher than the boiling point of said azeotroping agent with the vapor phase temperature being between that of the water azeotrope and no higher than 95° C. 2.
Claim 4
Dependent Claim
199 words
reacting a reaction mixture of at least one tetracarboxylic acid dianhydride of the formula: ##STR20## wherein Ar' is as defined above, and at least one aromatic diamine of the formula: C. H.sub.2 N--AR--NH.sub.2 wherein Ar is as defined above, at a molar ratio of dianhydride to diamine of m to m + 1 where m is zero or a positive integer of at least one and as high as n in formula (A), with the proviso that the reaction mixture contains 2 moles of an α,β-carboxylic acid monoanhydride of the formula ##STR21## in a phenol of the formula ##STR22## where each R' is hydrogen or --CH 3 in the presence of at least one organic azeotroping agent which: a. gives a water azeotrope having a boiling point less than 95° C at atmospheric pressure, b. is non-reactive with the dianhydride and the diamine, and c. separates from water as a distinct phase, said reaction conducted at a temperature less than 140° C and below the boiling point of said phenol and higher than the boiling point of said azeotroping agent with the vapor phase temperature being between that of the water azeotrope and no higher than 95° C. 2.
Claim 5
Dependent Claim
36 words
removing water of reaction and the azeotroping agent from the reaction mixture as a water azeotrope and 3. returning quantities of azeotroping agent to the reaction mixture to maintain the temperature and reaction mixture volume substantially
Claim 6
Dependent Claim
36 words
removing water of reaction and the azeotroping agent from the reaction mixture as a water azeotrope and 3. returning quantities of azeotroping agent to the reaction mixture to maintain the temperature and reaction mixture volume substantially
Claim 7
Dependent Claim
20 words
constant. 2. The process of claim 1 wherein the phenol is m-cresol or a mixture of m-cresol and its isomers.
Claim 8
Dependent Claim
20 words
The process of claim 1 wherein the organic azeotroping agent is a cyclic hydrocarbon having 6 to 8 carbon atoms.
Claim 9
Dependent Claim
13 words
The process of claim 3 wherein the cyclic hydrocarbon is an aromatic hydrocarbon.
Claim 10
Dependent Claim
13 words
The process of claim 4 wherein the aromatic hydrocarbon is benzene or toluene.
Claim 11
Dependent Claim
26 words
The process of claim 1 wherein Ar' is a tetravalent radical containing at least one ring of six carbon atoms, said ring characterized by benzenoid unsaturation.
Claim 12
Dependent Claim
70 words
The process of claim 6 wherein Ar is a divalent benzenoid radical selected from the group consisting of ##STR23## and multiples thereof connected to each other by R IV wherein R iv is selected from the group consisting of --CH=CH--, an alkylene chain of 1-3 carbon atoms, ##STR24## wherein R V and R VI are selected from the group consisting of alkyl and aryl of 1 to 6 carbon atoms.
Claim 13
Dependent Claim
33 words
The process of claim 7 wherein the phenol is m-cresol or a mixture of m-cresol and its isomers and the organic azeotroping agent is a cyclic hydrocarbon of 6 to 8 carbon atoms.
Claim 14
Dependent Claim
13 words
The process of claim 8 wherein the cyclic hydrocarbon is an aromatic hydrocarbon.
Claim 15
Dependent Claim
33 words
The process of claim 1 wherein the phenol is m-cresol or a mixture of m-cresol and its isomers and the organic azeotroping agent is a cyclic hydrocarbon of 6 to 8 carbon atoms.
Claim 16
Dependent Claim
74 words
The process of claim 1 wherein (1) the tetracarboxylic acid dianhydride is selected from the group consisting of 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, pyromelletic anhydride and 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, (2) the aromatic diamine is selected from the group consisting of m-phenylenediamine, p-phenylenediamine, 4,4'- oxydianiline, 3,3'-sulfonyldianiline, 4,4'-diaminobenzophenone, 4,4'-methylenedianiline and 4,4'-diaminostilbene, (3) phenol is m-cresol or mixtures of m-cresol and its isomers and (4) the organic azeotroping agent is a cyclic hydrocarbon of 6 to 8 carbon atoms.
Claim 17
Dependent Claim
13 words
The process of claim 11 wherein the cyclic hydrocarbon is an aromatic hydrocarbon.
Claim 18
Dependent Claim
17 words
The process of claim 12 wherein n is at least 4 and the aromatic hydrocarbon is benzene.
Claim 19
Dependent Claim
12 words
The process of claim 11 wherein the cyclic hydrocarbon is subsequently removed.
Claim 20
Dependent Claim
12 words
The process of claim 1 wherein the azeotroping agent is subsequently removed.
Claim 21
Dependent Claim
58 words
A polyimide having the formula: ##STR25## wherein Ar is a divalent aromatic organic radical, Ar' is a tetravalent aromatic organic radical, the four carbonyl groups being attached directly to separate carbon atoms and each pair of carbonyl groups being attached to adjacent carbon atoms in the Ar' radical, ##STR26## n has a numerical value of 1 to 100.
Claim 22
Dependent Claim
58 words
A polyimide having the formula: ##STR25## wherein Ar is a divalent aromatic organic radical, Ar' is a tetravalent aromatic organic radical, the four carbonyl groups being attached directly to separate carbon atoms and each pair of carbonyl groups being attached to adjacent carbon atoms in the Ar' radical, ##STR26## n has a numerical value of 1 to 100.
Claim 23
Dependent Claim
15 words
The polyimide of claim 16 which is soluble in phenol, cresols, xylenols or mixtures thereof.
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) | 1981-02-20 | 1981-08-22 | 1982-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-20 | 1985-08-22 | 1986-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-20 | 1989-08-22 | 1990-02-21 | $7700.00 | Window Closed / Lapsed |