US4438256A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Copolyamide acid and copolyimide
Assignee: Mitsubishi Chemical Corp
•
Filing: 1983-04-06
•
Granted: 1984-03-20
•
Expires: 2003-04-06
Abstract
Abstract A copolyamide acid comprising repeating units represented by the general formulas: ##STR1## in which the repeating unit (A) and the repeating unit (B) are present in a molar ratio from 20:80 to 80:20, and which has a logarithmic viscosity number (η inh ) of 0.5 dl/g--10 dl/g measured in N,N-dimethylformamide at a concentration of 0.5 g/dl and at a temperature of 30° C. and a copolyimide comprising repeating units represented by the general formulas: ##STR2## in which the repeating unit (C) and the repeating unit (D) are present in a molar ratio from 20:80 to 80:20 and which has a logarithmic viscosity number (η inh ) of o.5 dl/g--10 dl/g measured in 97% concentrated sulfuric acid at a concentration of 0.5 g/dl and at a temperature of 30° C.
Inventors
- 👤 Takayuki Ohta
- 👤 Yukio Yanaga
- 👤 Seiichi Hino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:27
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1067; C08G73/1071; C08G73/1042
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
65 words
A copolyamide acid consisting essentially of repeating units represented by the general formulas: ##STR5## in which the repeating unit (A) and the repeating unit (B) are present in a molar ratio from 20:80 to 80:20, and which has a logarithmic viscosity number (η inh ) of 0.5 dl/g--10 dl/g measured in N,N-dimethylformamide at a concentration of 0.5 g/dl and at a temperature of 30° C.
Claim 2
Dependent Claim
65 words
A copolyamide acid consisting essentially of repeating units represented by the general formulas: ##STR5## in which the repeating unit (A) and the repeating unit (B) are present in a molar ratio from 20:80 to 80:20, and which has a logarithmic viscosity number (η inh ) of 0.5 dl/g--10 dl/g measured in N,N-dimethylformamide at a concentration of 0.5 g/dl and at a temperature of 30° C.
Claim 3
Dependent Claim
67 words
A copolyimide consisting essentially of repeating units represented by the general formulas: ##STR6## in which the repeating unit (C) and the repeating unit (D) are present in a molar ratio from 20:80 to 80:20 and which has a logarithmic viscosity number (η inh ) of 0.5 dl/g--10 dl/g measured in 97% concentrated sulfuric acid at a concentration of 0.5 g/dl and at a temperature of 30° C.
Claim 4
Dependent Claim
67 words
A copolyimide consisting essentially of repeating units represented by the general formulas: ##STR6## in which the repeating unit (C) and the repeating unit (D) are present in a molar ratio from 20:80 to 80:20 and which has a logarithmic viscosity number (η inh ) of 0.5 dl/g--10 dl/g measured in 97% concentrated sulfuric acid at a concentration of 0.5 g/dl and at a temperature of 30° C.
Claim 5
Dependent Claim
21 words
The copolyamide acid of claim 1 wherein the molar ratio of repeating units (A) to (B) is from 30:70 to 70:30.
Claim 6
Dependent Claim
20 words
The copolyimide of claim 2 wherein the molar ratio of repeating units (C) to (D) is from 30:70 to 70:30.
Claim 7
Dependent Claim
41 words
The copolyimide of claim 2 wherein the logarithmic viscosity number η inh is in the range from 1 dl/g to 5 dl/g measured in 97% concentrated sulfuric acid at a concentration of 0.5 g/dl and at a temperature of 30° C.
References Cited (Backward Citations)
US3179632A
Cited
US3179630A
Cited
US3415782A
Cited
US3424718A
Cited
US3870677A
Cited
US4269968A
Cited
US4378400A
Cited
US4358581A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-20 | 1987-09-19 | 1988-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-20 | 1991-09-19 | 1992-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-20 | 1995-09-19 | 1996-03-20 | $7700.00 | Window Closed / Lapsed |