US4937133A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flexible base materials for printed circuits
Assignee: Nippon Steel Chemical and Materials Co Ltd
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Filing: 1989-03-27
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Granted: 1990-06-26
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Expires: 2009-03-27
Abstract
Abstract Flexible printed circuit base materials of this invention are composed of at least one layer of polyimide resins of low thermal expansion, at least one layer of polyimide resins of high thermal expansion with a higher linear expansion coefficient than that of the foregoing polyimide resins, and at least one layer of a conductor, highly reliable in dimensional stability to temperature changes, adhesive strength, and flatness after the etching, easy to work with in protection of the circuits made by etching.
Inventors
- 👤 Hisashi Watanabe
- 👤 Seiji Satou
- 👤 Akira Tokumitsu
- 👤 Kazuya Miyamoto
- 👤 Haruhiko Aoi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:37
CPC Classifications
H; H05; H05K; H05K1/00; H05K1/02; H05K1/03; C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1057; C08G73/106; C08G73/1064; C08G73/1067; C08G73/1071; C08G73/14; H05K1/0313; H05K1/0353; H05K1/036; H05K1/032; H05K1/0346; H05K1/0393; H05K2201/00; H05K2201/01; H05K2201/0137; H05K2201/0154; H05K2201/06; H05K2201/068; Y; Y10; Y10S; Y10S428/00; Y10S428/901; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24917; Y10T428/24942; Y10T428/31504; Y10T428/31678; Y10T428/31681; Y10T428/31721
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
75 words
Flexible printed circuit base materials which comprise at least one layer of polyimide resins having a low thermal expansion coefficient of 0 to less than 20×10 -6 (1/K), at least one layer of polyimide resins having a high thermal expansion coefficient of 20×10 -6 (1/K) or more, wherein the difference between higher linear expansion coefficient and said lower linear expansion coefficient is at least 5×10 -6 (1/K); and at least one layer of a conductor.
Claim 2
Dependent Claim
75 words
Flexible printed circuit base materials which comprise at least one layer of polyimide resins having a low thermal expansion coefficient of 0 to less than 20×10 -6 (1/K), at least one layer of polyimide resins having a high thermal expansion coefficient of 20×10 -6 (1/K) or more, wherein the difference between higher linear expansion coefficient and said lower linear expansion coefficient is at least 5×10 -6 (1/K); and at least one layer of a conductor.
Claim 3
Dependent Claim
71 words
Flexible printed circuit base materials according to claim 1 wherein the polyimide resins of low thermal expansion contain a structural unit of the general formula (I), ##STR9## in which Ar 1 is a divalent aromatic radical of the general formula ##STR10## R 1 to R 8 are independently of one another lower alkyl groups, lower alkoxy groups, or halogens, and n 1 to n 8 are integers of 0 to 4.
Claim 4
Dependent Claim
44 words
Flexible printed circuit base materials according to claim 1 wherein the polyimide resins of low thermal expansion contain a structural unit of the general formula (II), ##STR11## in which R 9 to R 12 are hydrogen, lower alkyl groups, lower alkoxy groups, or halogens.
Claim 5
Dependent Claim
28 words
Flexible printed circuit base materials according to claim 1 wherein the thermal expansion coefficient of the polyimide resins of low thermal expansion is 20×10 -6 (1/K) or less.
Claim 6
Dependent Claim
42 words
Flexible printed circuit base materials according to claim 1 wherein the polyimide resins of high thermal expansion contain a structural unit of the general formula (III), ##STR12## in which Ar 2 is a divalent organic radical with 12 or more carbon atoms.
Claim 7
Dependent Claim
14 words
Flexible printed circuit base materials according to claim 5 wherein Ar 2 is ##STR13##
Claim 8
Dependent Claim
42 words
Flexible printed circuit base materials according to claim 1 wherein the polyimide resins of high thermal expansion contain a structural unit of the general formula (IV), ##STR14## in which Ar 3 is a divalent aromatic radical with 12 or more carbon atoms.
Claim 9
Dependent Claim
27 words
Flexible printed circuit base materials according to claim 1 wherein conductors are on both sides and at least one layer of said conductors is a copper foil.
Claim 10
Dependent Claim
22 words
Flexible printed circuit base materials according to claim 1 wherein the layer adjoining the conductor is polyimide resins of high thermal expansion.
References Cited (Backward Citations)
JPS5623719A
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JPS5694698A
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US4526835A
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US4513055A
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US4569692A
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JPS60157280A
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JPS60243120A
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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) | 1993-06-25 | 1993-12-25 | 1994-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-25 | 1997-12-25 | 1998-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-25 | 2001-12-25 | 2002-06-26 | $7700.00 | Window Closed / Lapsed |