US4381210A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing polyimide tubes
Assignee: Nitto Denko Corp
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Filing: 1981-02-25
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Granted: 1983-04-26
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Expires: 2001-02-25
Abstract
Abstract A process for producing a polyimide tube which comprises applying a solution of polyamide acid obtained by reacting a biphenyltetracarboxylic acid dianhydride represented by the general formula ##STR1## with an aromatic diamine in an organic polar solvent to at least one surface of a polyimide film, drying thereafter the film with heating to convert a part of the polyamide acid into the imide form while controlling the volatile material content to about 5 to 60% by weight, by which a compound film having a heat-fusible layer composed of a polyimide precursor is obtained, winding the compound film on a heat resistant core material, heating to unify the compound film by the heat-fusible layer, and removing the heat resistant core material to obtain the polyimide tube.
Inventors
- 👤 Takashi Ishizuka
- 👤 Yasuhiro Moriyama
- 👤 Masao Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:59
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C08G73/1028; C08G73/1067; C08J; C08J7/00; C08J7/04; C08J7/0427; C08J7/043; F; F16; F16L; F16L9/00; F16L9/16; C08J2379/00; C08J2379/04; C08J2379/08; C08J2479/00; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1002; Y10T156/1036; Y10T156/1038
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
125 words
A process for producing a polyimide tube which comprises applying a solution of polyamide acid obtained by reacting a biphenyltetracarboxylic acid dianhydride represented by the general formula ##STR3## with an aromatic diamine in an organic polar solvent to at least one surface of a polyimide film, drying thereafter the film with heating to convert a part of said polyamide acid into the imide form while controlling the volatile material content to about 5 to 50% by weight, by which a compound film having a heat-fusible layer composed of a polyimide precursor is obtained, winding said compound film on a heat resistant core material, heating to unify the compound film by said heat-fusible layer, and removing the heat resistant core material to obtain said polyimide tube.
Claim 2
Dependent Claim
125 words
A process for producing a polyimide tube which comprises applying a solution of polyamide acid obtained by reacting a biphenyltetracarboxylic acid dianhydride represented by the general formula ##STR3## with an aromatic diamine in an organic polar solvent to at least one surface of a polyimide film, drying thereafter the film with heating to convert a part of said polyamide acid into the imide form while controlling the volatile material content to about 5 to 50% by weight, by which a compound film having a heat-fusible layer composed of a polyimide precursor is obtained, winding said compound film on a heat resistant core material, heating to unify the compound film by said heat-fusible layer, and removing the heat resistant core material to obtain said polyimide tube.
Claim 3
Dependent Claim
20 words
The process for producing a polyimide tube according to claim 1, wherein said polyimide film is a heat-shrinkable polyimide film.
Claim 4
Dependent Claim
47 words
The process for producing a polyimide tube according to claim 1, wherein said biphenyltetracarboxylic acid dianhydride is 3,4,3',4'-biphenyltetracarboxylic acid dianhydride, 2,3,3',4'-biphenyltetracarboxylic acid dianhydride, or 2,3,2',3'-biphenyltetracarboxylic acid dianhydride and wherein said aromatic diamine is m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene or 3,4-diaminobenzanilide.
Claim 5
Dependent Claim
26 words
The process for producing a polyimide tube according to claim 1, wherein said solution of polyamide acid has an inherent viscosity of about 0.5 or more.
Claim 6
Dependent Claim
39 words
The process for producing a polyimide tube according to claim 1, wherein said polyimide film is a film produced from a polyimide obtained on reacting an aromatic tetracarboxylic acid dianhydride with an aromatic diamine in an organic polar solvent.
Claim 7
Dependent Claim
27 words
The process for producing a polyimide tube according to claim 1, wherein said drying with heating is at a temperature of about 50° to about 200° C.
Claim 8
Dependent Claim
38 words
The process for producing a polyimide tube according to claim 1, wherein said heat-shrinkable polyimide film is a polyimide film stretched in at least the monoaxial direction to a stretching ratio of about 1.05 to about 5 times.
References Cited (Backward Citations)
US3762982A
Cited
US3996203A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-04-25 | 1986-10-25 | 1987-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-04-25 | 1990-10-25 | 1991-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-04-25 | 1994-10-25 | 1995-04-26 | $7700.00 | Window Closed / Lapsed |