POLYIMIDE PRECURSOR COMPOSITION AND POLYIMIDE FILM, SUBSTRATE FOR DISPLAY DEVICE, AND OPTICAL DEVICE PREPARED BY USING SAME

Abstract

The present disclosure provides a polyimide film having improved heat resistance and refractive index by using a polyimide precursor composition comprising a diamine of Chemical Formula 1 and an acid dianhydride of Chemical Formula 2 as polymerization components, thereby reducing the difference in refractive index from the upper layer to improve bottom emission efficiency.

Claims

1. A polyimide precursor composition comprising, as polymerization components, one or more diamines including a diamine of Chemical Formula 1; and one or more acid dianhydrides including a tetracarboxylic dianhydride of Chemical Formula 2: ##STR00017##

2. The polyimide precursor composition of claim 1, wherein the polymerization components further include a diamine of Chemical Formula 4: ##STR00018## in the Chemical Formula 4, each Z is independently one selected from CONH, —NHCO, —C(═O)O— and —OC(═O), R.sub.1, R.sub.2 and R.sub.3 are each independently selected from a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms and an aryl group having 6 to 18 carbon atoms, n1, n2 and n3 are each independently an integer of 0 to 4, and m is an integer of 1 to 3.

3. The polyimide precursor composition of claim 1, wherein the diamine of Chemical Formula 1 is included in an amount of 70 mol % or more with respect to the total content of the diamines.

4. The polyimide precursor composition of claim 1, wherein the tetracarboxylic dianhydride of Chemical Formula 2 is included in an amount of 70 mol % or more with respect to the total content of the acid dianhydrides.

5. The polyimide precursor composition of claim 1, wherein a polyamic acid contained in the polyimide precursor composition includes the repeating structure of Chemical Formula 3 in an amount of 70 mol % or more with respect to the total content of the entire repeating structures: ##STR00019##

6. The polyimide precursor composition of claim 2, wherein the diamine of Chemical Formula 4 is included in an amount of more than 0 and 30 mol % or less with respect to the total content of the diamines.

7. The polyimide precursor composition of claim 1, wherein a polyamic acid contained in the polyimide precursor composition includes a repeating structure of Chemical Formula 5: ##STR00020## in the Chemical Formula 5, each Z is independently one selected from —CONH, —NHCO—, —C(═O)O— and —OC(═O), R.sub.1, R.sub.2 and R.sub.3 are each independently selected from a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms and an aryl group having 6 to 18 carbon atoms, n1, n2 and n3 are each independently an integer of 0 to 4, and m is an integer of 1 to 3.

8. A polyimide film comprising a cured product of the polyimide precursor composition according to claim 1.

9. A method for preparing a polyimide film comprising the stets of: coating the polyimide precursor composition according to claim 1 onto a carrier substrate; and heating and curing the coated polyimide precursor composition.

10. The polyimide film of claim 8, wherein the polyimide film has a refractive index in the in-plane direction of at least 1.75 at a wavelength of 532 nm.

11. The polyimide film of claim 8, wherein the polyimide film has a transmittance at a wavelength of 450 nm of at least 75% as measured according to JIS K 7105.

12. The polyimide film of claim 8, wherein the polyimide film has a CTE of −5 ppm/° C. or more and +15 ppm/° C. or less.

13. A substrate for display device comprising the polyimide film of claim 8.

14. An optical device comprising the polyimide film of claim 8.

Description

COMPARATIVE EXAMPLE 1

[0129] The organic solvent DEAc was filled in a reactor under a stream of nitrogen, and then 0.821 mol of TEMB (2,2′-bis(trifluoromethyl)benzidine) was added and dissolved at the same temperature while maintaining the reactor temperature at 25° C. 0.821 mol of PMDA was added to the TFMB-added solution at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

COMPARATIVE EXAMPLE 2

[0130] The organic solvent DEAc was filled in a reactor under a stream of nitrogen, and then 0.902 mol of TFMB (2,2′-bis(trifluoromethyl)benzidine) was added and dissolved at the same temperature while maintaining the reactor temperature at 25° C. 0.902 mol of BPDA was added to the TFMB-added solution at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

COMPARATIVE EXAMPLE 3

[0131] The organic solvent DEAc was filled in a reactor under a stream of nitrogen, and then 0.793 mol of diamine of Chemical Formula 1 was added and dissolved at the same temperature, while maintaining the reactor temperature at 25° C. 0.793 mol of PMDA was added to the diamine of Chemical Formula 1-added solution at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

COMPARATIVE EXAMPLE 4

[0132] The organic solvent DEAc was filled in a reactor under a stream of nitrogen, and then 0.3965 mol of diamine of Chemical Formula 1 and 0.3965 mol of TFMB (2,2′-bis(trifluoromethyl)benzidine) were added and dissolved at the same temperature while maintaining the reactor temperature at 25° C. 0.6344 mol of 6-FDA and 0.1586 mol of PMDA were added to the diamine of Chemical Formula 1 and TFMB-added solution at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

EXAMPLE 1

[0133] The organic solvent DEAc was filled in a reactor under a stream of nitrogen, and then 0.735 mol of diamine of Chemical Formula 1 was added and dissolved at the same temperature while maintaining the reactor temperature at 25° C. 0.735 mol of BPDA was added to the diamine of Chemical Formula 1-added solution at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

EXAMPLE 2

[0134] The organic solvent DEAc was filled in a reactor under a stream of nitrogen, and then 0.668 mol of diamine of Chemical Formula 1 and 0.067 mol of diamine of Chemical Formula 4-1 were added and dissolved at the same temperature while maintaining the reactor temperature at 25° C. 0.735 mol of BPDA was added to the diamines of Chemical Formulas 1 and 4-1 added solution at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

##STR00014##

EXAMPLE 3

[0135] The organic solvent DEAc was filled in a reactor under a stream of nitrogen, and then 0.668 mol of diamine of Chemical Formula 1 and 0.067 mol of diamine of Chemical Formula 4-2 were added and dissolved at the same temperature while maintaining the reactor temperature at 25° C. 0.735 mol of BPDA was added to the diamines of Chemical Formulas 1 and 4-2 added solution at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

##STR00015##

EXAMPLE 4

[0136] The organic solvent DEAc was filled in a reactor under a stream of nitrogen, and then 0.668 mol of diamine of Chemical Formula 1 and 0.067 mol of diamine of Chemical Formula 4-3 were added and dissolved at the same temperature while maintaining the reactor temperature at 25° C. 0.735 mol of BPDA was added to the diamines of Chemical Formulas 1 and 4-3 added solution at the same temperature and stirred for 24 hours to obtain a polyimide precursor composition.

##STR00016##

EXPERIMENTAL EXAMPLE 1

[0137] Each of the polyimide precursor compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 3 was spin coated on a glass substrate. The polyimide precursor composition-coated glass substrate was put in an oven and heated at a rate of 5° C./min, and a curing process was performed by maintaining at 80° C. for 30 minutes and at 300° C. for 30 minutes, thereby preparing a polyimide film.

[0138] Physical properties of each film were measured and shown in Table 1 below.

[0139] <Measurement of Transmittance>

[0140] The transmittance in a 450 nm wavelength was measured with a transmittance meter (model name HR-100, Murakami Color Research Laboratory) based on JIS K 7105.

[0141] <Measurement of Refractive Index>

[0142] The prepared polyimide film was peeled off and the refractive index was measured at a wavelength of 532 nm using a prism coupler.

[0143] <Pyrolysis Temperature (Td1%)>

[0144] The temperature at which the weight loss rate of the polymer was 1% in a nitrogen atmosphere was measured using TGA.

[0145] <Coefficient of Thermal Expansion (CTE) and Glass Transition Temperature (Tg)>

[0146] The film was prepared in a size of 5×20 mm and then a sample was loaded using an accessory. A length of the film to be actually measured was set to be equal to 16 mm. A force pulling the film was set at 0.02N, A primary heating step was performed at a heating rate of 5° C./min in a temperature range of 100° C. or more and 350° C. or less, and then cooling was performed at a cooling rate of 4° C./min in a temperature range from 350° C. to 100° C. The aspect of the change in thermal expansion was measured using TMA (Q400, TA Instruments).

TABLE-US-00001 TABLE 1 Refractive index (532 nm) Curing Transmittance Thickness In-plane Thickness CTE Td_1% Sample condition (%) 450 nm (μm) direction(TE) direction(TM) (ppm/° C.) (° C.) Comparative 300° C. 72 11.01 1.6649 1.5117 −6.504 523 Example 1 (PMDA- TFMB) Comparative 300° C. 80 8.47 1.6748 1.5077 29.09 545 Example 2 (BPDA- TFMB) Comparative 300° C. 61 11.01 1.7171 1.5421 −8.114 521 Example 3 (PMDA- Formula 1) Comparative 300° C. 67 10.81 1.691 1.528 18.19 519 Example 4 (6FDA/PMDA- Formula 1/ TFMB) Example 1 300° C. 82 8.32 1.7733 1.5426 −3.854 542 (BPDA- Formula 1) Example 2 300° C. 80 8.35 1.7596 1.5483 −0.25 539 (BPDA- Formula 1/ Formula 4-1) Example 3 300° C. 79 9.01 1.7672 1.5635 −2.31 542 (BPDA- Formula 1/ Formula 4-2) Example 4 300° C. 83 8.56 1.7601 1.5593 3.41 541 (BPDA- Formula 1/ Formula 4-3)

[0147] From the results in Table 1, it can be seen that the polyimide film according to the present disclosure shows a high refractive index in the in-plane direction, and the refractive index can be significantly improved compared to the polyimide film of the other comparative example. In addition the polyimide film according to the present disclosure shows a low CTE value, which may mean that the shrinkage behavior or change of the film due to heating is very small, from which it can be seen that the polyimide film according to the present disclosure has excellent heat resistance.

[0148] While the present invention has been particularly shown and described with reference to specific embodiments thereof, it will be apparent to those skilled in the art that this specific description is merely a preferred embodiment and that the scope of the invention is not limited thereby. It is therefore intended that the scope of the invention be defined by the claims appended hereto and their equivalents.