WO2021027099A1

WO2021027099A1 - Polyimide, preparation method therefor and flexible oled panel

Info

Publication number: WO2021027099A1
Application number: PCT/CN2019/115784
Authority: WO
Inventors: 汪亚民
Original assignee: 武汉华星光电半导体显示技术有限公司
Priority date: 2019-08-15
Filing date: 2019-11-05
Publication date: 2021-02-18
Also published as: CN110540643B; CN110540643A

Abstract

Disclosed in the present invention are a polyimide, a preparation method therefor and a flexible OLED panel. Provided is a polyimide which is formed by polymerizing a dianhydride monomer containing a naphthalene ring structure and a diamine monomer, and is end-capped with a dianhydride containing a pyridine structure.

Description

Polyimide, preparation method thereof and flexible OLED panel

Technical field

The invention relates to the field of OLED materials, in particular to a polyimide and a preparation method thereof and a flexible OLED panel.

Background technique

OLED display technology is the most active display panel development direction in recent years. It has excellent characteristics of light weight, bendable, foldable and even rollable. Among them, the flexible substrate as the support and protection component of the entire flexible device is not only for the display of the device Quality has an important impact, and it will directly affect the life of the device. Polyimide (PI) is a type of polymer material with imide ring repeating units. The rigid imide ring gives the material excellent comprehensive properties, making polyimide the first choice for flexible display substrates. .

technical problem

For OLED flexible substrates, there are extremely high comprehensive performance requirements, that is, optical transparency, heat resistance, dimensional stability (thermal dimensional stability) to thermal cycles in the device manufacturing process, and film flexibility. Although the polyimide base material is superior to the current inorganic glass substrate in terms of flexibility and film formability, its heat resistance and thermal dimensional stability are still poor.

Technical solutions

To solve the above problems, the technical solution provided by the present invention is as follows:

The invention provides a polyimide, which is formed by polymerizing a dianhydride monomer containing a naphthalene ring structure and a halogenated diamine monomer, and is terminated by using a dicarboxylic anhydride containing a pyridine structure.

In the polyimide provided in the embodiments of the present application, the structure of the polyimide is represented by formula (1):

Wherein, Ar ₁ is a heteroaryl group containing a pyridine structure with 5-30 carbon atoms;

Ar ₂ is an aryl group containing a naphthalene ring structure with 12-30 carbon atoms;

Ar ₃ is a halogenated alkyl group with 1-30 carbon atoms, a halogenated aryl group with 6-30 carbon atoms or a halogenated heteroaryl group with 3-30 carbon atoms;

n is any integer from 1000 to 2500.

In the polyimide provided in the embodiment of the present application, the Ar _{1 is} selected from any one of the following structural formulas:

and

In the polyimide provided in the embodiment of the present application, the Ar _{2 is} selected from any of the following structural formulas:

and

In the polyimide provided by the embodiment of the present application, the Ar _{3 has} a centrosymmetric structure and contains fluorine element.

In the polyimide provided in the embodiment of the present application, the Ar _{3 is} selected from any one of the following structural formulas:

and

In the polyimide provided in the embodiments of the present application, the polyimide is selected from any one of the following structural formulas:

versus

The present invention also provides a preparation method of polyimide, including the following steps:

S1: Under the protection of argon, the compound A

With compound B

Dissolve completely in the first organic solvent, then add the compound CH ₂ N-Ar ₃ -NH ₂ , stir and react at room temperature for the first time to obtain the first reaction liquid,

Among them, Ar ₁ is a heteroaryl group containing a pyridine structure with 5-30 carbon atoms,

Ar ₂ is an aryl group containing a naphthalene ring structure with 12-30 carbon atoms,

And Ar ₃ is a halogenated alkyl group having 1 to 30 carbon atoms, a halogenated aryl group having 6 to 30 carbon atoms, or a halogenated heteroaryl group having 3 to 30 carbon atoms;

S2: Add a second organic solvent to the first reaction solution, raise the temperature to the first temperature and react for the second time under the protection of argon, and then lower the temperature to the second temperature, and then filter the solution with an organic filter membrane to obtain a filtrate ；

S3: The filtrate is coated on the substrate, and then dried in a vacuum environment at a third temperature to remove 60-80wt% of the first organic solvent and the second organic solvent, and then sent to a high-temperature furnace for the first Bake in a four-temperature environment to obtain a substrate with film adhesion;

S4: Soak the substrate with the film attached in deionized water for a third time, peel off the film attached to the substrate, and then dry the film at a fifth temperature to obtain a polyimide film.

In the preparation method of polyimide provided in the embodiment of the present application, in the S1 step, the first time is 24-96h.

In the preparation method of the polyimide provided in the embodiment of the present application, in the S1 step, the molar ratio of the compound A:B:C is 1:(20-50):(20-50).

In the preparation method of polyimide provided in the embodiment of the application, in the S1 step, the Ar _{1 is} selected from any one of the following structural formulas:

and

In the preparation method of the polyimide provided by the embodiment of the present application, in the S1 step, the Ar _{2 is} selected from any one of the following structural formulas:

and

In the preparation method of polyimide provided by the embodiment of the present application, in the S1 step, the Ar _{3 is} selected from any one of the following structural formulas:

and

In the preparation method of polyimide provided by the embodiment of the present application, in the step S2, the first temperature is 150-250°C, the second time is 4-6h, and the second temperature It is 20-90°C.

In the preparation method of polyimide provided by the embodiment of the present application, in the S3 step, the third temperature is 60-100°C, and the fourth temperature is 420-500°C.

In the preparation method of polyimide provided in the embodiment of the present application, in the S4 step, the third time is 72-96 h, and the fifth temperature is 60-80°C.

In the preparation method of polyimide provided in the embodiment of the present application, after removing 60-80wt% of the first organic solvent and the second organic solvent, the S3 step further includes: Feed the substrate at 100-140℃, let it stand for 20-60min, and then repeat more than once at a heating rate of 1-10℃/min to 180-380℃, bake for 10-60min, and then 1-10℃/ The heating rate is increased to 420-500°C for 20-90 minutes, and the temperature is lowered to below 180°C at a cooling rate of 1-10°C/min, and then the substrate is taken out.

In the preparation method of polyimide provided in the embodiment of the present application, after removing 60-80wt% of the first organic solvent and the second organic solvent, the S3 step further includes: Feed the substrate at 100-140℃, let it stand for 20-60min, then heat up to 420-500℃ at a heating rate of 1-10℃/min, bake for 40-90min, and finally at a cooling rate of 1-10℃/min After cooling to below 180°C, the substrate was taken out.

The present invention also provides a flexible OLED panel, which includes the above-mentioned polyimide.

Beneficial effect

The beneficial effects of the present invention are: the present invention increases the content of the benzene ring by introducing the dianhydride containing the naphthalene ring structure into the polyimide, that is, increases the heat resistance components, thereby significantly improving the heat resistance; On the one hand, the dianhydride containing a pyridine structure is used for end-capping to prevent excessive polymerization and reduced flexibility caused by group explosion. This kind of polyimide has excellent heat resistance and deformation resistance, and is suitable for use in flexible OLED panel substrate materials and packaging film materials.

Description of the drawings

In order to explain the embodiments or the technical solutions in the prior art more clearly, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are merely inventions For some embodiments, those of ordinary skill in the art can obtain other drawings based on these drawings without creative work.

1 is a schematic diagram of the steps of high-temperature baking of polyimide in Example 1 of the present invention;

2 is a schematic diagram of the steps of high-temperature baking of polyimide in Example 2 of the present invention;

3 is a schematic diagram of the steps of high-temperature baking of polyimide in Example 3 of the present invention;

4 is a graph of fitting data of polyimide thermal weight loss test in Examples 1 and 2 of the present invention;

FIG. 5 is a fitting diagram of test data of polyimide thermal expansion coefficient in Example 1 of the present invention;

Fig. 6 is a fitting diagram of the test data of the thermal expansion coefficient of polyimide in Example 2 of the present invention.

The best mode of the invention

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the protection scope of the present invention.

Example 1: Preparation of polyimide 1, the structure is shown as follows:

The synthetic route is as follows:

The synthesis steps include the following:

S1: Under the protection of argon, the

(20mmol) and

(1mol) completely dissolved in N-methylpyrrolidone (NMP solvent), add

(1mol), stirring at room temperature for 24h;

S2: Add 10 mL of toluene to the reacted solution, raise the temperature to 150°C for 6 hours under the protection of argon, then lower the temperature to 80°C, and filter the solution with an organic filter membrane to obtain a filtrate;

S3: Coat the obtained filtrate on a glass substrate, and then dry it in a vacuum environment of 60°C to remove 70% of the solvent, and then send the glass substrate with the film into a high-temperature furnace, the sheet temperature is 120°C, and the temperature is kept constant Let stand for 30 minutes, then heat up to 450°C at a temperature increase rate of 4°C/min, bake at a constant temperature for 60 minutes, and then cool down to 120°C at a temperature drop rate of 7°C/min, and then discharge the film (see Figure 1 for the high temperature baking process) ；

S4: Soak the film-attached substrate obtained in step S3 in deionized water for 72 hours, peel off the film attached to the substrate, and dry the film at 80° C. to obtain a polyimide film.

The thermal weight loss test was performed on the prepared polyimide, and the result is shown in Figure 4. The temperature when the weight loss is 1% is 595°C;

The thermal expansion coefficient of the prepared polyimide was tested. The results are shown in Figure 5. The thermal expansion coefficient at 50℃-300℃ is 3.521ppm/K, and the thermal expansion coefficient at 50℃-400℃ is 8.338ppm/ K.

Example 2: Preparation of polyimide 2, the structure is shown as follows:

The synthetic route is as follows:

The synthesis steps include the following:

S1: Under the protection of argon, the

(50mmol) and

(1mol) completely dissolved in N-methylpyrrolidone (NMP solvent), add

(1mol), stirred and reacted at room temperature for 96h;

S2: Add 18 mL of toluene to the reacted solution, raise the temperature to 250°C for 4 hours under the protection of argon, then lower the temperature to 80°C, and filter the solution with an organic filter membrane to obtain a filtrate;

S3: Coat the obtained filtrate on a glass substrate, and then dry it in a vacuum environment of 80°C to remove 70% of the solvent, and then send the glass substrate with the film into a high-temperature furnace, and the sheet-in temperature is 120°C and kept at a constant temperature Let stand for 30 minutes, then heat up to 180°C with a heating time of 20 minutes, let stand for 20 minutes, then heat up to 350°C with a heating time of 40 minutes, let stand for 20 minutes, then heat up to 450°C with a temperature of 30 minutes, bake for 40 minutes, and finally After cooling down to 120°C at a constant temperature for 48 minutes, the film is discharged (see Figure 2 for the high-temperature baking process);

S4: Soak the film-attached substrate obtained in step S3 in deionized water for 96 hours, peel off the film attached to the substrate, and dry the film at 80° C. to obtain a polyimide film.

The thermal weight loss test was performed on the prepared polyimide, and the result is shown in Figure 4. The temperature when the weight loss is 1% is 604°C;

The thermal expansion coefficient of the prepared polyimide was tested. The results are shown in Figure 6. The thermal expansion coefficient at 50℃-300℃ is 2.349ppm/K, and the thermal expansion coefficient at 50℃-400℃ is 5.988ppm/ K.

Example 3: Preparation of polyimide 3, the structure is shown as follows:

The synthetic route is as follows:

The synthesis steps include the following:

S1: Under the protection of argon, the

(30mmol) and

(1mol) completely dissolved in N-methylpyrrolidone (NMP solvent), add

(1mol), stirring at room temperature for 72h;

S2: Add 10 mL of toluene to the reacted solution, raise the temperature to 200°C for 5 hours under the protection of argon, then lower the temperature to 80°C, and filter the solution with an organic filter membrane to obtain a filtrate;

S3: Coat the obtained filtrate on a glass substrate, and then dry it in a vacuum environment of 80°C to remove 70% of the solvent, and then send the glass substrate with the film into a high-temperature furnace, and the sheet-in temperature is 120°C and kept at a constant temperature Let stand for 30 minutes, then heat up to 475°C at a temperature increase rate of 4°C/min, bake at a constant temperature for 60 minutes, and then cool down to 120°C at a temperature drop rate of 7°C/min, and then discharge the film (see Figure 3 for the high temperature baking process) ；

S4: Soak the film-attached substrate obtained in step S3 in deionized water for 80 hours, peel off the film attached to the substrate, and dry the film at 80° C. to obtain a polyimide film.

Perform a thermal weight loss test on the prepared polyimide, and the temperature when the weight loss is 1% is 602°C;

The thermal expansion coefficient of the prepared polyimide was tested, and the thermal expansion coefficient was 2.621 ppm/K at 50°C to 300°C, and the thermal expansion coefficient was 6.056 ppm/K at 50°C to 400°C.

From the foregoing embodiments, it can be determined that the polyimide provided by the present invention has a leading level of heat resistance and deformation resistance, and is particularly suitable for use as a flexible OLED substrate material.

The above provides a detailed introduction to a polyimide and its preparation method provided in the embodiments of the present invention. Specific examples are used in this article to illustrate the principles and implementation of the present invention. The description of the above embodiments is only for help Understand the method of the present invention and its core idea; at the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation and the scope of application. In summary, the content of this specification should not It is understood as a limitation of the present invention.

Claims

A polyimide, wherein the polyimide is formed by polymerizing a dianhydride monomer containing a naphthalene ring structure and a halogenated diamine monomer, and is terminated with a dicarboxylic anhydride containing a pyridine structure.
The polyimide according to claim 1, wherein the structure of the polyimide is represented by formula (1):

Wherein, Ar 1 is a heteroaryl group containing a pyridine structure with 5-30 carbon atoms;

Ar 2 is an aryl group containing a naphthalene ring structure with 12-30 carbon atoms;

Ar 3 is a halogenated alkyl group with 1-30 carbon atoms, a halogenated aryl group with 6-30 carbon atoms or a halogenated heteroaryl group with 3-30 carbon atoms;

n is any integer from 1000 to 2500.
The polyimide of claim 2, wherein said Ar 1 is selected from any of the following structural formulae:

and
The polyimide of claim 2, wherein the Ar 2 is selected from any of the following structural formulas:

and
The polyimide according to any one of claims 2, wherein the Ar 3 has a centrosymmetric structure and contains a fluorine element.
The polyimide of claim 5, wherein the Ar 3 is selected from any of the following structural formulas:

and
The polyimide of claim 2, wherein the polyimide is selected from any one of the following structural formulas:

versus
A preparation method of polyimide, which comprises the following steps:

S1: Under the protection of argon, the compound A
With compound B
Completely dissolve in the first organic solvent, then add the compound CH 2 N-Ar 3 -NH 2 , stir and react at room temperature for the first time to obtain the first reaction liquid,

Among them, Ar 1 is a heteroaryl group containing a pyridine structure with 5-30 carbon atoms,

Ar 2 is an aryl group containing a naphthalene ring structure with 12-30 carbon atoms,

And Ar 3 is a halogenated alkyl group having 1 to 30 carbon atoms, a halogenated aryl group having 6 to 30 carbon atoms, or a halogenated heteroaryl group having 3 to 30 carbon atoms;

S2: Add a second organic solvent to the first reaction solution, raise the temperature to the first temperature and react for the second time under the protection of argon, and then lower the temperature to the second temperature, and then filter the solution with an organic filter membrane to obtain a filtrate ；

S3: The filtrate is coated on the substrate, and then dried in a vacuum environment at a third temperature to remove 60-80wt% of the first organic solvent and the second organic solvent, and then sent to a high-temperature furnace for the first Bake in a four-temperature environment to obtain a substrate with film adhesion;

S4: Soak the substrate with the film attached in deionized water for a third period of time, peel off the film attached to the substrate, and then dry the film at a fifth temperature to obtain a polyimide film.
8. The preparation method of polyimide according to claim 8, wherein, in the S1 step, the first time is 24-96h.
8. The preparation method of polyimide according to claim 8, wherein, in the step S1, the molar ratio of the compound A:B:C is 1:(20-50):(20-50).
8. The preparation method of polyimide according to claim 8, wherein in the step S1, the Ar 1 is selected from any one of the following structural formulae:

and
8. The preparation method of polyimide according to claim 8, wherein in the step S1, the Ar 2 is selected from any one of the following structural formulas:

and
8. The preparation method of polyimide according to claim 8, wherein in the step S1, the Ar 3 is selected from any one of the following structural formulas:

and
The preparation method of polyimide according to claim 8, wherein in the S2 step, the first temperature is 150-250°C, the second time is 4-6h, and the second temperature It is 20-90°C.
8. The preparation method of polyimide according to claim 8, wherein in the step S3, the third temperature is 60-100°C, and the fourth temperature is 420-500°C.
8. The preparation method of polyimide according to claim 8, wherein in the step S4, the third time is 72-96h, and the fifth temperature is 60-80°C.
8. The preparation method of polyimide according to claim 8, wherein after removing 60-80wt% of the first organic solvent and the second organic solvent, the S3 step further comprises: Feed the substrate at 100-140℃, let it stand for 20-60min, and then repeat more than once at a heating rate of 1-10℃/min to 180-380℃, bake for 10-60min, and then 1-10℃/ The heating rate is increased to 420-500°C for 20-90 minutes, and the temperature is lowered to below 180°C at a cooling rate of 1-10°C/min, and then the substrate is taken out.
8. The preparation method of polyimide according to claim 8, wherein after removing 60-80wt% of the first organic solvent and the second organic solvent, the S3 step further comprises: Feed the substrate at 100-140℃, let it stand for 20-60min, then heat up to 420-500℃ at a heating rate of 1-10℃/min, bake for 40-90min, and finally at a cooling rate of 1-10℃/min After cooling to below 180°C, the substrate was taken out.
A flexible OLED panel, wherein the flexible OLED panel comprises the polyimide according to claim 1.