Polyimide film

Patent metadata

Field	Value
Publication number	US-9388287-B2
Application number	US-201113638660-A
Country	US
Kind code	B2
Filing date	Mar 30, 2011
Priority date	Mar 30, 2010
Publication date	Jul 12, 2016
Grant date	Jul 12, 2016

Abstract

The present invention provides a polyimide film having a good transparency and also an excellent thermal resistance so that it is useful in a transparent conductive film, TFT substrate, a flexible printing circuit substrate, and the like.

First claim

The invention claimed is:

1. A polyimide powder that is an imide of polyamic acid obtained by polymerizing a diamine and at least two acid dianhydrides, wherein a degree of imidization of the polyimide powder is not less than 80%; a specific refractive index increment (dn/dc) of the polyimide powder is 0.100 to 0.1800; and the acid dianhydrides comprise 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, and at least one selected from the group consisting of 4-(2,5-dioxotetrahydrofuran-3)-1,2,3,4-tetrahydronaphtalene-1,2-dicarboxylic anhydride and 4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride);
wherein the imide of the polyamic acid is obtained by lastly injecting the 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride during the polymerization of the diamine and the acid dianhydrides; and
wherein the specific refractive index increment (dn/dc) is defined as follows:
Specific refractive index increment (dn/dc): the value is that a change rate of refractive index according to the change rate of dilute solution concentration is differentiated and is measured within the range of 0.001 to 0.1 g/ml that is a section of concentration change when detecting a refractive index through injecting the polyimide powder in a state of dilute solution in an organic solvent inside flow cell of differential refractometer.

2. The polyimide powder according to claim 1 , wherein the specific refractive index increment (dn/dc) is 0.100 to 0.1300.

3. The polyimide powder according to claim 1 , wherein 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride is included in 30 mol % to 80 mol % based on the total amount of the acid dianhydrides.

4. The polyimide powder according to claim 1 , wherein the diamine includes 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl.

5. The polyimide powder according to claim 4 , wherein 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl is included in 20 mol % to 100 mol % based on the total amount of the diamine.

6. The polyimide powder according to claim 1 , wherein the polymerization is performed for 5 to 24 hours.

7. The polyimide powder according to claim 6 , wherein the polymerization is performed for 8 to 12 hours.

8. A method for producing a polyimide powder, comprising:
obtaining a solution of a polyamic acid by polymerizing a diamine and at least two acid dianhydrides in an organic solvent;
preparing a solution containing an imide that is imidized in an imidization degree of not less than 80% by injecting a chemical converting agent to the solution of the polyamic acid;
precipitating by adding a solvent selected from the group consisting of water, methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, triethylene glycol, 2-butyl alcohol, 2-propyl alcohol, 2-hexyl alcohol, cyclophentyl alcohol, cyclohexyl alcohol, phenol and t-butyl alcohol to the solution containing the imide; and
filtering of the solids that are precipitated;
wherein the specific refractive index increment (dn/dc) is defined as follows is 0.100 to 0.1800:
Specific refractive index increment (dn/dc): the value is that a change rate of refractive index according to the change rate of dilute solution concentration is differentiated and is measured within the range of 0.001 to 0.1 g/ml that is a section of concentration change when detecting a refractive index through injecting the polyimide powder in a state of dilute solution in an organic solvent inside flow cell of differential refractometer;
wherein the acid dianhydrides comprise 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, and at least one selected from the group consisting of 4-(2,5-dioxotetrahydrofuran-3)-1,2,3,4-tetrahydronaphtalene-1,2-dicarboxylic anhydride and 4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride); and
wherein the imide of the polyamic acid is obtained by lastly injecting the 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride during the polymerization of the diamine and the acid dianhydrides.

9. A polyimide film that is obtained by casting an imide of a polyamic acid that is obtained by polymerizing a diamine and at least two acid dianhydrides, wherein a specific refractive index increment (dn/dc) that is defined as follows is 0.100 to 0.1800:
Specific refractive index increment (dn/dc): the value is that a change rate of refractive index according to the change rate of dilute solution concentration is differentiated and is measured within the range of 0.001 to 0.1 g/ml that is a section of concentration change when detecting a refractive index through injecting the polyimide film in a state of dilute solution in an organic solvent inside flow cell of differential refractometer;
wherein the acid dianhydrides comprise 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, and at least one selected from the group consisting of 4-(2,5-dioxotetrahydrofuran-3)-1,2,3,4-tetrahydronaphtalene-1,2-dicarboxylic anhydride and 4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride); and
wherein the imide of the polyamic acid is obtained by lastly injecting the 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride during the polymerization of the diamine and the acid dianhydrides.

10. The polyimide film according to claim 9 , wherein the specific refractive index increment (dn/dc) is 0.100 to 0.1300.

11. The polyimide film according to claim 9 , wherein 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride is included in 30 mol % to 80 mol % based on the total amount of the acid dianhydrides.

12. The polyimide film according to claim 9 , wherein the diamine includes 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl.

13. The polyimide film according to claim 12 , wherein 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl is included in 20 mol % to 100 mol % based on the total amount of the diamine.

14. The polyimide film according to claim 9 , wherein the polymerization is performed for 1 to 24 hours.

15. The polyimide film according to claim 14 , wherein the polymerization is performed for 8 to 12 hours.

16. The polyimide film according to claim 9 , wherein a degree of yellowness is not more than 4.5 based on a film thickness of 50˜100 μm.

17. The polyimide film according to claim 9 , wherein a mean coefficient of linear thermal expansion (CTE) is not more than 70 ppm/° C., in which the mean coefficient of linear thermal expansion (CTE) is measured within the range of 50 to 250° C. using a thermomechanical analysis based on a film thickness of 50˜100 μm.

18. A method for producing a polyimide film, comprising:
obtaining a solution of a polyamic acid by polymerizing a diamine and at least two acid dianhydrides in an organic solvent;
preparing a solution containing an imide that is imidized in an imidization degree of not less than 80% by injecting a chemical converting agent to the solution of the polyamic acid;
precipitating by adding a solvent selected from the group consisting of water, methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, triethylene glycol, 2-butyl alcohol, 2-propyl alcohol, 2-hexyl alcohol, cyclophentyl alcohol, cyclohexyl alcohol, phenol and t-butyl alcohol to the solution containing the imide; and
filtering of the solids that are precipitated;
wherein the specific refractive index increment (dn/dc) is defined as follows is 0.100 to 0.1800:
Specific refractive index increment (dn/dc): the value is that a change rate of refractive index according to the change rate of dilute solution concentration is differentiated and is measured within the range of 0.001 to 0.1 g/ml that is a section of concentra

Assignees

• Jeong Young Han
• Park Hyo Jun
• Kolon Inc

Inventors

• Jeong Young Han
• Park Hyo Jun

Classifications

• C08J5/18 Primary

  Manufacture of films or sheets · CPC title

• C08L2201/08

  Stabilised against heat, light or radiation or oxydation · CPC title

• C08G73/1067

  Wholly aromatic polyimides, i.e. having both tetracarboxylic and diamino moieties aromatically bound · CPC title

• C08G73/1039

  comprising halogen-containing substituents · CPC title

• C08L2203/16

  used for films · CPC title