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Patent US4464489A successfully refreshed from Google Patents.
US4464489A
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Method for the production of polyimide powder
Assignee: Nitto Denko Corp
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Filing: 1983-12-12
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Granted: 1984-08-07
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Expires: 2003-12-12
Abstract
Abstract Spherical porous polyimide powder having an average particle diameter of 1 to 20 μm which is infusible and insoluble in organic solvents is produced by polymerizing an aromatic tetracarboxylic acid dianhydride and an aromatic polyisocyanate in an organic solvent at a temperature of 100° to 200° C. and in the presence of a tertiary amine catalyst to form polyimide particles in the form of slurry, filtering or centrifuging said polyimide particles, and washing the resulting polyimide particles with an organic solvent.
Inventors
- 👤 Yuzuru Noda
- 👤 Toshio Nakajima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:48
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/12; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/30; C08G18/34; C08G18/343; C08G18/346; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1035; C08J2379/00; C08J2379/04; C08J2379/08
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
102 words
A process for producing spherical porous polyimide powder comprising: (a) polymerizing at least one aromatic tetracarxylic acid dianhydride which forms an infusible insoluble polyimide and an approximately the same quantity of at least one aromatic polyisocyanate in an organic solvent at a temperature of 100° to 200° C. and in the presence of a tertiary amine catalyst to form said polyimide particles in the form of slurry; (b) filtering or centrifuging said polyimide particles; and (c) washing the resulting polyimide particles with an organic solvent, wherein the resulting spherical porous polyimide powder has an average particle diameter of 1 to 20 μm.
Claim 2
Dependent Claim
102 words
A process for producing spherical porous polyimide powder comprising: (a) polymerizing at least one aromatic tetracarxylic acid dianhydride which forms an infusible insoluble polyimide and an approximately the same quantity of at least one aromatic polyisocyanate in an organic solvent at a temperature of 100° to 200° C. and in the presence of a tertiary amine catalyst to form said polyimide particles in the form of slurry; (b) filtering or centrifuging said polyimide particles; and (c) washing the resulting polyimide particles with an organic solvent, wherein the resulting spherical porous polyimide powder has an average particle diameter of 1 to 20 μm.
Claim 3
Dependent Claim
35 words
The process of claim 1, wherein the aromatic tetracarboxylic acid dianhydride is at least one member selected from the group consisting of pyromellitic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride and 2,3,3',4'-biphenyltetracarboxylic acid dianhydride.
Claim 4
Dependent Claim
35 words
The process of claim 1, wherein the aromatic polyisocyanate is at least one member selected from the group consisting of diphenylmethane-4,4'-diisocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, naphthalene-2,6-diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, diphenylether-4,4'-diisocyanate and a polyisocyanate containing an isocyanurate ring.
Claim 5
Dependent Claim
43 words
The process of claim 1, wherein the aromatic tetracarboxylic acid dianhydride is selected from the group consisting of pyromellitic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, and 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, and the aromatic polyisocyanate is selected from the group consisting of diphenylmethane-4,4'-diisocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, and diphenylether-4,4'-diisocyanate.
Claim 6
Dependent Claim
26 words
The process of claim 1, wherein the organic solvent is selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, hexamethylphosphortriamide, N,N'-dimethyl-2-imidazolidinone, cresol, phenol, and xylenol.
Claim 7
Dependent Claim
29 words
The process of claim 1, wherein the tertiary amine catalyst is selected from the group consisting of triethylamine, tri-n-butylamine, 1,8-diazabicyclo-(5,4,0)-undecene-7 and a complex thereof, dimethylbutylamine, N,N-dimethyl-p-toluidine, N,N-dimethylaniline and N,N-dimethylbenzylamine.
Claim 8
Dependent Claim
29 words
The process of claim 1, wherein the tertiary amine catalyst is employed in an amount of from 0.05 to 10 mol% per 1 mole of aromatic tetracarboxylic acid dianhydride.
Claim 9
Dependent Claim
14 words
The process of claim 1, wherein the reaction temperature is 110° to 180° C.
References Cited (Backward Citations)
US3300420A
Cited
US4263410A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-07 | 1988-02-06 | 1988-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-07 | 1992-02-06 | 1992-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-07 | 1996-02-06 | 1996-08-07 | $7700.00 | Window Closed / Lapsed |