Process for preparing a tough, soluble, aromatic, thermoplastic copolyimide

• US 5,639,850 A
• Filed: 05/18/1995
• Issued: 06/17/1997
• Est. Priority Date: 12/16/1994
• Status: Expired due to Term

• Current Assignee: United States Incorporated, United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Bryant, Robert G.
• Primary Examiner(s): Acquah, Samuel A.
• Assistant Examiner(s): HAMPTON HIGHTOWER, PATRICIA
• Application Number:
  US08/444,185
• Time in Patent Office: 761 Days
• Field of Search: 528/353, 528/125, 528/128, 528/172, 528/173, 528/185, 528/176, 528/188, 528/220, 528/229, 528/350
• US Class Current: 528/353
• CPC Class Codes: C08G 73/1042 Copolyimides derived from at least two different tetracarboxylic compounds or two different diamino compounds
• CPC Class Codes: C08G 73/1053 with oxygen only in the tetracarboxylic moiety
• CPC Class Codes: C08G 73/1071 Wholly aromatic polyimides containing oxygen in the form of ether bonds in the main chain
• CPC Class Codes: Y10S 526/935 Hot melt adhesive
• CPC Class Codes: Y10T 428/2971 Impregnation
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]
• CPC Class Codes: Y10T 428/31721 Of polyimide

Abstract

A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide is provided. The process comprises the steps of (a) providing 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride at a mole ratio ranging from about 25 mole percent to 75 mole percent to 75 mole percent to about 25 mole percent; (b) adding 3,4'"'"'-oxydianiline to form a mixture; c) adding a polar aprotic or polar protic solvent to the mixture to form a solution having a percentage of solids capable of maintaining polymer solubility; (d) stirring the solution to allow it to react; (e) adding an azeotropic solvent to the solution and heating to remove water; (f) cooling the solution of step (e) to room temperature and recovering the tough, soluble, aromatic, thermoplastic copolyimide.

Claims

1. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide, the process comprising the steps of:

(a) providing 4,4'"'"'-oxydiphthalic anhydride and 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride at a mole ratio ranging from about 25 mole percent to about 75 mole percent 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride to about 75 mole percent to about 25 mole percent 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride;

(b) adding 3,4'"'"'-oxydianiline to the 4,4'"'"'-oxydiphthalic anhydride and 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride to form a mixture;

(c) adding a solvent to the mixture to form a solution having a percentage of solids effective in maintaining polymer solubility, wherein the solvent is selected from the group consisting of;

polar aprotic and polar protic;

(d) stirring the solution at room temperature to allow the 3,4'"'"'-oxydianiline, 4,4'"'"'-oxydiphthalic anhydride and 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride to react;

(e) adding an azeotropic solvent to the solution and heating the solution to a temperature effective in removing water;

(f) cooling the solution to room temperature and recovering the tough, soluble, aromatic thermoplastic copolyimide.

2. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 1, wherein the solvent is selected from the group consisting of:

N,N'"'"'-dimethyl acetamide, N-methylpyrrolidinone, dimethyl formamide and m-cresol.

3. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 2, wherein the solvent is N,N'"'"'-dimethyl acetamide, the mole ratio of 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 50 mole percent to 50 mole percent and the percentage of solids is 15 mole percent.

4. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 2, wherein the solvent is N-methylpyrrolidinone, the mole ratio of 4,4'"'"'-oxydiphthalic anbydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 75 mole percent to 25 mole percent and the percentage of solids is 15 mole percent.

5. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 2, wherein the solvent is N-methylpyrrolidinone, the mole ratio of 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 50 mole percent to 50 mole percent and the percentage of solids is up to 60 mole percent.

6. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 2, wherein the solvent is N-methylpyrrolidinone, the mole ratio of 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 25 mole percent to 75 mole percent and the percentage of solids is 15 mole percent.

7. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 2, wherein the solvent is m-cresol, the mole ratio of 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 50 mole percent to 50 mole percent and the percentage of solids is 25 mole percent.

8. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 1, wherein an endcapper is employed after step (a) of claim 1 at an amount ranging from about 2 mole percent to about 10 mole percent.

9. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 8, wherein the endcapper is selected from the group consisting of a monofunctional anhydride and a monofunctional amine.

10. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 9, wherein the endcapper is phthalic anhydride.

11. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 8, wherein the solvent is selected from the group consisting of:

N,N'"'"'-dimethyl acetamide, N-methylpyrrolidinone, dimethyl formamide and m-cresol.

12. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 11, wherein the solvent is N,N'"'"'-dimethyl acetamide, the mole ratio of 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 50 mole percent to 50 mole percent and the percentage of solids is 15 mole percent.

13. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 11, wherein the solvent is N-methylpyrrolidinone, the mole ratio of 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 75 mole percent to 25 mole percent and the percentage of solids is 15 mole percent.

14. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 11, wherein the solvent is N-methylpyrrolidinone, the mole ratio of 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 50 mole percent to 50 mole percent and the percentage of solids is up to 60 mole percent.

15. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 11, wherein the solvent is N-methylpyrrolidinone, the mole ratio of 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 25 mole percent to 75 mole percent and the percentage of solids is 15 mole percent.

16. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 11, wherein the solvent is m-cresol, the mole ratio of 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 50 mole percent to 50 mole percent and the percentage of solids is 25 mole percent.

17. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 10, wherein the solvent is selected from the group consisting of:

N,N'"'"'-dimethyl acetamide, N-methylpyrrolidinone, dimethyl formamide and m-cresol.

18. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 17, wherein the solvent is N,N'"'"'-dimethyl acetamide, the mole ratio of 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 50 mole percent to 50 mole percent and the percentage of solids is 15 mole percent.

19. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 17, wherein the solvent is N-methylpyrrolidinone, the mole ratio of 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 75 mole percent to 25 mole percent and the percentage of solids is 15 mole percent.

20. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 17, wherein the solvent is N-methylpyrrolidinone, the mole ratio of 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 50 mole percent to 50 mole percent and the percentage of solids is up to 60 mole percent.

21. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 17, wherein the solvent is N-methylpyrrolidinone, the mole ratio of 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 25 mole percent to 75 mole percent and the percentage of solids is 15 mole percent.

22. A process for preparing a tough, soluble, aromatic, thermoplastic copolyimide according to claim 17, wherein the solvent is m-cresol, the mole ratio of 4,4'"'"'-oxydiphthalic anhydride to 3,4,3'"'"',4'"'"'-biphenyltetracarboxylic dianhydride is 50 mole percent to 50 mole percent and the percentage of solids is 25 mole percent.