US5049649A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Colorless films formed from fluorinated polyimides
Assignee: CNA Holdings LLC
•
Filing: 1989-12-27
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Granted: 1991-09-17
•
Expires: 2009-12-27
Abstract
Abstract A colorless, optically clear film consisting essentially of a polyimide of the formula: ##STR1## wherein R is ##STR2## is disclosed. The composition forming the film has a weight average molecular weight, M w of at least 75,000, and has as an essential characteristic at least about 80% optical transmission at electromagnetic wavelengths of 400 nanometers and above when formed into a thickness of about two thousandths of an inch.
Inventors
- 👤 H. Vora Rohitkumar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 00:17
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1039
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
165 words
A colorless, optically clear film consisting essentially of a polyimide of the formula: ##STR5## wherein R is ##STR6## and wherein said composition has a weight average molecular weight, M w of at least 100,000, and wherein said film has as an essential characteristic at least 80% optical transmission at electromagnetic wavelengths of 400 nanometers and above when formed into a thickness of two thousandths of an inch; said film being free-standing and flexible, and also being formed from a fully imidized precursor which was synthesized in accordance with the process of: (a) dispersing a diamine and a dianhydride in a first solvent and polymerizing the reactants at a temperature of below about 35 degrees Celsius to form a polyamic acid; (b) chemically cyclizing said polyamic acid to form a polyimide of said reactants while maintaining the temperature below about 35 degrees Celsius; and (c) precipitating said polyimide reaction product by dissolving said first solvent in a second solvent in which said polyimide is not solvable.
Claim 2
Dependent Claim
165 words
A colorless, optically clear film consisting essentially of a polyimide of the formula: ##STR5## wherein R is ##STR6## and wherein said composition has a weight average molecular weight, M w of at least 100,000, and wherein said film has as an essential characteristic at least 80% optical transmission at electromagnetic wavelengths of 400 nanometers and above when formed into a thickness of two thousandths of an inch; said film being free-standing and flexible, and also being formed from a fully imidized precursor which was synthesized in accordance with the process of: (a) dispersing a diamine and a dianhydride in a first solvent and polymerizing the reactants at a temperature of below about 35 degrees Celsius to form a polyamic acid; (b) chemically cyclizing said polyamic acid to form a polyimide of said reactants while maintaining the temperature below about 35 degrees Celsius; and (c) precipitating said polyimide reaction product by dissolving said first solvent in a second solvent in which said polyimide is not solvable.
Claim 3
Dependent Claim
23 words
The composition according to claim 1, wherein the weight average molecular weight, M w , of said composition is at least about 150,000.
Claim 4
Dependent Claim
23 words
The composition according to claim 2, wherein the weight average molecular weight, M w , of said composition is at least about 200,000.
Claim 5
Dependent Claim
20 words
The composition according to claim 3, wherein the weight average molecular weight, M w , is at least about 250,000.
Claim 6
Dependent Claim
22 words
The composition according to claim 1, wherein the polydispersity of said polyimide forming said film is from about 1.8 to about 2.6.
Claim 7
Dependent Claim
22 words
The composition according to claim 5, wherein the polydispersity of said polyimide forming the film is from about 1.9 to about 2.4.
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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) | 1994-09-16 | 1995-03-18 | 1995-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-16 | 1999-03-18 | 1999-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-16 | 2003-03-18 | 2003-09-17 | $7700.00 | Window Closed / Lapsed |