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Patent US5460890A successfully refreshed from Google Patents.
US5460890A
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Biaxially stretched isotropic polyimide film having specific properties
Assignee: EIDP Inc
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Filing: 1992-02-26
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Granted: 1995-10-24
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Expires: 2012-02-26
Abstract
Abstract An isotropic, biaxially stretched polyimide film prepared by casting a solution of a polyamic acid precursor in an organic solvent containing a cyclization catalyst and dehydrating agent onto the surface of a support, imidizing the polyamic acid to give a continuous self-supporting gel film containing 5-50% by weight of solids, stretching the gel film in the machine direction (MD) at a ratio of 1.1-1.9, and stretching in the transverse direction (TD) with respect to the machine direction so as to maintain a TD/MD stretch ratio of from 0.9 to 1.3.
Inventors
- 👤 Masakazu Okahashi
- 👤 Akimitsu Tsukuda
- 👤 Tsuneyoshi Miwa
- 👤 James R. Edman
- 👤 Charles M. Paulson, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:41
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B29; B29C; B29C55/00; B29C55/02; B29C55/10; B29C55/12; B29C55/14; B29C55/143; B29D; B29D7/00; B29D7/01; H; H05; H05K; H05K1/00; H05K1/02; H05K1/03; H05K1/0313; H05K1/032; H05K1/0346; B29K; B29K2079/00; B29K2079/08; C08J2379/00; C08J2379/04; C08J2379/08; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31678; Y10T428/31681; Y10T428/31721
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
34 words
An isotropic, biaxially stretched polyimide film comprising pyromellitic dianhydride and 4,4'-diaminodiphenylether having an in-plane anisotropy index of not more than 20 and an average coefficient of thermal expansion (CTE) of less than 31 ppm/°C.
Claim 2
Dependent Claim
34 words
An isotropic, biaxially stretched polyimide film comprising pyromellitic dianhydride and 4,4'-diaminodiphenylether having an in-plane anisotropy index of not more than 20 and an average coefficient of thermal expansion (CTE) of less than 31 ppm/°C.
Claim 3
Dependent Claim
20 words
The isotropic, biaxially stretched polyimide film of claim 1 laminated to a metal foil with a heat resistant polyester/epoxy adhesive.
Claim 4
Dependent Claim
19 words
The isotropic, biaxially stretched polyimide film of claim 2 laminated to a metal foil, wherein the metal is copper.
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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) | 1998-10-23 | 1999-04-24 | 1999-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-10-23 | 2003-04-24 | 2003-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-10-23 | 2007-04-24 | 2007-10-24 | $7700.00 | Window Closed / Lapsed |