Polyimide precursor, polyimide, polyimide film, polyimide metal laminate, and polyimide solution

1. A polyimide precursor comprising a structural unit represented by general formula (AI):

wherein A is tetravalent aromatic group or aliphatic group, B is a divalent aromatic group, and each R 2 independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms,

wherein B in general formula (AI) comprises a triazine moiety represented by the following formula (AB1):

wherein R 1 is hydrogen, an alkyl group having 1 to 6 carbon atoms or an aromatic group, and R 3 is hydrogen, methyl or ethyl.

2. A polyimide precursor according to claim 1 , wherein A in general formula (AI) comprises a tetravalent aromatic group obtainable by removing two carboxylic anhydride groups from a compound selected from the group consisting of 3,3′,4,4 ′-biphenyltetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride and 3,3′,4,4 ′-benzophenonetetracarboxylic dianhydride.

3. A polyimide precursor according to claim 1 , wherein A in general formula (AI) comprises a tetravalent aromatic group obtainable by removing two carboxylic anhydride groups from pyromellitic dianhydride.

4. A polyimide precursor according to claim 1 , wherein B in general formula (AI) comprises the triazine moiety represented by general formula (AB 1) in an amount of 10 to 100 mol %.

5. A polyimide obtainable from the polyimide precursor according to claim 1 , comprising a structural unit represented by general formula (AII):

wherein A and B are as defined above.

6. A polyimide film comprising the polyimide according to claim 5 .

7. A metal laminate comprising the polyimide film according to claim 6 and a metal layer laminated on the polyimide film directly or via an adhesive.

8. A process for manufacturing a polyimide film, comprising:

reacting a tetracarboxylic dianhydride component with a diamine component comprising a diamine compound represented by general formula (AB2) in an organic solvent;

removing the organic solvent to obtain a solid polyimide;

dissolving the solid polyimide in an organic solvent;

flow-casting or applying the obtained polyimide solution on a support; and

heating at 80 to 150 ° C. or lower,

wherein R 1 is hydrogen, an alkyl group having 1 to 6 carbon atoms or an aromatic group, and R 3 is hydrogen, methyl or ethyl.

9. A process for manufacturing a polyimide film, comprising:

reacting a tetracarboxylic dianhydride component with a diamine component comprising a diamine compound represented by general formula (AB2) in an organic solvent;

removing the organic solvent to obtain a solid polyimide;

dissolving the solid polyimide in an organic solvent;

flow-casting or applying the obtained polyimide solution on a support; and

heating at 280 to 350 ° C. or lower,

wherein R 1 is hydrogen, an alkyl group having 1 to 6 carbon atoms or an aromatic group, and R 3 is hydrogen, methyl or ethyl.

10. A polyimide solution comprising a polyimide dissolved in an organic solvent, the polyimide comprising a structural unit represented by general formula (BII):

wherein A is a tetravalent aromatic group or aliphatic group, and B is a divalent aromatic group,

wherein in the polyimide, B in general formula (BII) comprises a triazine moiety represented by the following formula (BB 1):

wherein R 1 and R 2 each independently represent hydrogen or alkyl or aryl having 1 to 12 carbon atoms, and R 3 is hydrogen, methyl or ethyl.

11. The polyimide solution according to claim 10 , wherein in the polyimide, B in general formula (BII) comprises the triazine moiety in which R 1 and R 2 are both phenyl.

12. The polyimide solution according to claim 10 , wherein in the polyimide, A in general formula (BII) comprises a tetravalent residue obtainable by removing two carboxylic anhydride groups from a compound selected from the group consisting of 3,3′,4,4′-biphenyltetracarboxylic dianhydride, 3,3′,4,4′-diphenyl sulfone-tetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride and 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride.

13. The polyimide solution according to claim 10 , wherein in the polyimide, A in general formula (BII) comprises a tetravalent residue obtainable by removing two carboxylic anhydride groups from 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride.

14. The polyimide solution according to claim 10 , wherein the organic solvent is selected from the group consisting of N-methylpyrrolidone, N,N-dimethylacetamide and γ-butyrolactone.

15. The polyimide solution according to claim 13 , wherein the organic solvent is tetrahydrofuran or γ-butyrolactone.

16. The polyimide solution according to claim 10 , wherein B in general formula (BII) comprises the triazine moiety represented by general formula (BB1) in an amount of 10 to 100 mol %.

17. A method for producing a polyimide solution according to claim 10 , the method comprising:

producing a polyimide precursor solution comprising a polyimide precursor and a first organic solvent, wherein the polyimide precursor comprises a structural unit represented by general formula (BI):

wherein A is tetravalent aromatic group or aliphatic group, B is a divalent aromatic group, and each R 4 independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms, wherein B in general formula (BI) comprises a triazine moiety represented by following formula (BB 1):

wherein each R 1 and R 2 independently represents hydrogen or alkyl or aryl having 1 to 12 carbon atoms, and R 3 represents hydrogen, methyl or ethyl;

imidizing while removing the first organic solvent to obtain a polyimide; and

dissolving the obtained polyimide in a second organic solvent to obtain the polyimide solution.

18. A method for producing a polyimide solution according to claim 17 , wherein tetracarboxylic dianhydride component constituting A in formula (BI) comprises 3,3′,4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride, wherein a molar ratio of 3,3′,4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride is 75/25 to 25/75.

19. A method for producing a polyimide solution according to claim 10 , the method comprising:

reacting tetracarboxylic dianhydride component with diamine component comprising a triazine compound represented by general formula (BB2):

wherein each R 1 and R 2 independently represents hydrogen or alkyl or aryl having 1 to 12 carbon atoms, and R 3 represents hydrogen, methyl or ethyl,

to form a first polyimide solution comprising a polyimide and a first organic solvent; the polyimide comprising a structural unit represented by general formula (BII):

wherein A is tetravalent aromatic group or aliphatic group, and B is divalent aromatic group, wherein in the polyimide, B in general formula (BII) comprises a triazine moiety represented by the following formula (BB1):

wherein each R 1 and R 2 independently represents hydrogen or alkyl or aryl having 1 to 12 carbon atoms, and R 3 represents hydrogen, methyl or ethyl;

obtaining a polyimide in a form of solid from the first polyimide solution; and

dissolving the obtained polyimide in a form of solid in a second organic solvent to obtain a second polyimide solution.

20. A method for producing a polyimide solution according to claim 10 , wherein the tetracarboxylic dianhydride component comprising A in formula (BI) comprises 3,3′,4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride, wherein a molar ratio of 3,3′,4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride is 75/25 to 50/50.