Polyimide-based solution and polyimide-based film produced using same

Patent metadata

Field	Value
Publication number	US-10144847-B2
Application number	US-201515027533-A
Country	US
Kind code	B2
Filing date	Jun 1, 2015
Priority date	May 30, 2014
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

The present invention relates to a polyimide-based solution that can be used to produce an isotropic transparent polyimide-based film with high heat resistance and excellent mechanical properties as well as high transmittance. A coating of the polyimide-based solution on a substrate has a haze of 1% or less after storage at a temperature of 30° C. and a humidity of 70% for 30 minutes.

First claim

What is claimed is:

1. A polyimide-based solution comprising a polyimide comprising a polyamic acid comprising a structure of Formula 2:

wherein X is a tetravalent organic group derived from an acid dianhydride and Y is a divalent organic group derived from a diamine, and
a solvent,
wherein a coating of the polyimide-based solution on a substrate has a haze of 1% or less after storage at a temperature of 30° C. and a humidity of 70% for 30 minutes, wherein the solvent has a positive partition coefficient (Log P) at 25° C.,
wherein X comprises a tetravalent organic group having a fluorine atom-containing substituent, Y comprises a divalent organic group having a fluorine atom-containing substituent, or each of X and Y comprises an organic group having a fluorine atom-containing substituent,
wherein the molar ratio of the tetravalent organic group having a fluorine atom-containing substituent to all tetravalent organic groups in X is from 0.1:1 to 0.9:1, and
wherein the molar ratio of the divalent organic group having a fluorine atom-containing substituent to all divalent organic groups in Y is from 0.1:1 to 0.9:1.

2. The polyimide-based solution according to claim 1 , wherein the divalent organic groups are each independently selected from divalent aromatic organic groups, divalent alicyclic organic groups, divalent aliphatic organic groups, and combinations thereof and the tetravalent organic groups are each independently selected from tetravalent aromatic organic groups, tetravalent alicyclic organic groups, tetravalent aliphatic organic groups, and combinations thereof.

3. The polyimide-based solution according to claim 1 , wherein Y in each of the polyimide and the polyamic acid comprises both a divalent organic group having a fluorine atom-containing substituent and a divalent organic group having no fluorine atom-containing substituent.

4. The polyimide-based solution according to claim 1 , wherein the divalent organic group having a fluorine atom-containing substituent comprises a divalent monocyclic or polycyclic aromatic organic group, a divalent monocyclic or polycyclic alicyclic organic group, or a divalent organic group having a structure in which two or more divalent organic groups selected from divalent monocyclic or polycyclic aromatic organic groups and divalent monocyclic or polycyclic alicyclic organic groups are linked to each other via a single bond or a linking group.

5. The polyimide-based solution according to claim 1 , wherein the divalent organic group having a fluorine atom-containing substituent is a divalent monocyclic or polycyclic aromatic organic group, a divalent monocyclic or polycyclic alicyclic organic group, or a divalent organic group having a structure in which two or more divalent organic groups selected from divalent monocyclic or polycyclic aromatic organic groups and divalent monocyclic or polycyclic alicyclic organic groups are linked to each other via a single bond or a linking group, and the fluorine atom-containing substituent is directly substituted on the aromatic or alicyclic ring or is substituted on the linking group.

6. The polyimide-based solution according to claim 1 , wherein the divalent organic group having a fluorine atom-containing substituent is derived from 2,2′-bis(trifluoromethyl)benzidine or 2,2-bis[4-(-aminophenoxy)phenyl]hexafluoropropane.

7. The polyimide-based solution according to claim 3 , wherein the divalent organic group having no fluorine atom-containing substituent is derived from at least one compound selected from 4,4′-oxydianiline, 4,4′-(9-fluorenylidene)dianiline, para-phenylenediamine, and meta-phenylenediamine.

8. The polyimide-based solution according to claim 1 , wherein X in each of the polyimide and the polyamic acid comprises a tetravalent organic group having a fluorine atom-containing substituent and a tetravalent organic group having no fluorine atom-containing substituent.

9. The polyimide-based solution according to claim 1 , wherein the tetravalent organic group having a fluorine atom-containing substituent comprises a tetravalent monocyclic or polycyclic aromatic organic group, a tetravalent monocyclic or polycyclic alicyclic organic group, or a tetravalent organic group having a structure in which two or more tetravalent organic groups selected from tetravalent monocyclic or polycyclic aromatic organic groups and tetravalent monocyclic or polycyclic alicyclic organic groups are linked to each other via a single bond or a linking group.

10. The polyimide-based solution according to claim 1 , wherein the tetravalent organic group having a fluorine atom-containing substituent is a tetravalent monocyclic or polycyclic aromatic organic group, a tetravalent monocyclic or polycyclic alicyclic organic group, or a tetravalent organic group having a structure in which two or more tetravalent organic groups selected from tetravalent monocyclic or polycyclic aromatic organic groups and tetravalent monocyclic or polycyclic alicyclic organic groups are linked to each other via a single bond or a linking group, and the fluorine atom-containing substituent is directly substituted on the aromatic or alicyclic ring or is substituted on the linking group.

11. The polyimide-based solution according to claim 1 , wherein the tetravalent organic group having a fluorine atom-containing substituent is derived from 4,4′-(hexafluoroisopropylidene)diphthalic anhydride.

12. The polyimide-based solution according to claim 8 , wherein the tetravalent organic group having no fluorine atom-containing substituent is derived from at least one compound selected from 3,3′,4,4′-biphenyltetracarboxylic dianhydride, 2,3,3′,4′-biphenyltetracarboxylic dianhydride, pyromellitic anhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 4,4′-oxydiphthalic anhydride, and 2,3,3′,4′-oxydiphthalic anhydride.

13. The polyimide-based solution according to claim 1 , wherein the polyimide-based solution has a viscosity of 400 cP to 50,000 cP, as measured using a Brookfield rotational viscometer at 25° C.

14. A polyimide-based film produced by applying the polyimide-based solution according to claim 1 to one side of a substrate, curing the polyimide-based solution to form a polyimide-based film, and separating the polyimide-based film from the substrate.

15. The polyimide-based film according to claim 14 , wherein the polyimide has a glass transition temperature of at least 250° C. and the film has a transmittance of at least 85% to light at a wavelength of 380 to 760 nm in the thickness range of 10 to 30 μm.

16. The polyimide-based film according to claim 14 , wherein the film has a coefficient of thermal expansion (CTE) of 70 ppm/K or less at 250° C.

17. The polyimide-based film according to claim 14 , wherein the film has an in-plane retardation (R in ) of 0.01 to 1 nm and a thickness retardation (R th ) of 100 nm or less.

18. The polyimide-based film according to claim 14 , wherein the film has a thickness retardation (R th ) of at least 100 nm.

19. The polyimide-based film according to claim 14 , wherein the film has a yellowness index (YI) of 9 or less and a modulus of at least 1.0 GPa.

20. A display substrate comprising the polyimide-based film according to claim 14 .

21. A device comprising the polyimide-based film according to claim 14 .

Assignees

• Lg Chemical Ltd

Inventors

• Yun Cheolmin
• Shin Bora
• Jeong Hye Won
• Kim Kyungjun
• Park Hangah

Classifications

• G09F9/301

  flexible foldable or roll-able electronic displays, e.g. thin LCD, OLED · CPC title

• G02F1/133305

  Flexible substrates, e.g. plastics, organic film · CPC title

• C08J2379/08

  Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title

• C08G73/1078

  wholly aromatic in the diamino moiety · CPC title