CN112341929A

CN112341929A - Polyamide acid solution primer, preparation method and application thereof

Info

Publication number: CN112341929A
Application number: CN201910725710.3A
Authority: CN
Inventors: 李臻; 陈超; 孙立民; 张东
Original assignee: Jiangsu Jitri Smart Liquid Crystal Sci and Tech Co Ltd
Current assignee: Jiangsu Jitri Smart Liquid Crystal Sci and Tech Co Ltd
Priority date: 2019-08-07
Filing date: 2019-08-07
Publication date: 2021-02-09

Abstract

The invention discloses a method for preparing a polyamic acid solution primer, which comprises the following steps: the polyamic acid solution and the silica nanoparticles are uniformly mixed to prepare the polyamic acid solution primer, wherein the polyamic acid solution primer can improve the heat resistance of the main body film, improve the adhesiveness of the main body film, and improve the material of the display substrate. The invention also discloses the polyamic acid solution primer prepared by the method, a method for preparing a film by using the polyamic acid solution primer, and application of the polyamic acid solution primer in a display substrate. The polyamic acid solution primer disclosed by the invention can improve the heat resistance of the main body film, improve the adhesiveness of the main body film, avoid the foaming defect and be more suitable for being used as a material of a display substrate. The polyamic acid solution primer with excellent characteristics can be used for substrate pretreatment to manufacture flexible OLED devices.

Description

Polyamide acid solution primer, preparation method and application thereof

Technical Field

The invention relates to a polyamic acid solution primer, a preparation method and application thereof, in particular to a polyamic acid solution primer as a heat-resistant polyimide precursor, a preparation method and application thereof.

Background

The flexible display has the characteristics of lightness, thinness and insusceptibility to breakage, has diversified appearance forms and infinite product design possibilities. Compared with a Liquid Crystal Display (LCD), an Organic Light Emitting Diode (OLED) display has a simple structure and is more suitable for manufacturing a flexible display. The market size of OLED displays was about $ 12.5 billion in 2010, with a projected growth to $ 160 billion by 2020. The OLED has high luminous efficiency and high contrast, and can be widely applied to mobile phones, digital cameras, navigators, commercial signs and the like. In order to meet the requirements of low energy consumption, quick response and high resolution, the development of an Active Matrix OLED (AMOLED) display device is accelerated, and the application of the Active Matrix OLED (AMOLED) display device in mobile phones and other fields is promoted. These characteristics depend to a large extent on the processing temperature of their electronic components. A Thin Film Transistor (TFT) array of the AMOLED is deposited on a substrate base plate, and the deposition temperature greatly affects the electronic characteristics of the TFT. When glass is the substrate material, it can withstand extremely high deposition temperatures (greater than 500 ℃), resulting in a TFT with excellent characteristics. However, glass is inherently thicker, heavier and brittle, limiting the design and versatility of display products. Mobile phone manufacturers have a high call for displays that are lightweight, thin, and non-fragile. The polymer substrate material enables flexible displays.

The polymer material is hopeful to be used as an ideal substrate material due to the characteristics of small specific gravity, good flexibility, difficult breakage and easy film preparation, and is used for manufacturing flexible electronic devices. Compared with rigid glass substrates, flexible substrate materials in electronic devices have many significant advantages, such as being light and thin, not prone to breakage, and the like.

The polymer solution can be cast in situ as a polymer film on a glass substrate. And after all functional layers are manufactured on the polymer film/glass substrate, peeling off the glass substrate to obtain the flexible display device taking the polymer film as the substrate. In this process, the thickness of the polymer thin film is typically 10 to 50 micrometers, which must withstand the extremely high temperatures in TFT fabrication, so the thermal stability of the polymer thin film is critical for the fabrication of flexible OLEDs. The polymer film must maintain good dimensional stability and good adhesion to the glass before separation from the glass substrate.

The invention discloses a high molecular polymer solution primer which is used for: 1) the good fit of the polymer film to the glass is reinforced; and 2) improving the heat resistance of the polymer film body. The primer of the present invention is first coated on a glass substrate for modification, and then coated on a main body film for improving the adhesion property. Meanwhile, in the research, the coating of the primer can further increase the heat resistance of the polymer main body film and increase the thermal decomposition temperature.

Disclosure of Invention

The purpose of the invention is as follows:

the invention aims to provide a method for preparing a polyamic acid solution primer, the polyamic acid solution primer prepared by the method, a method for preparing a film by using the polyamic acid solution primer and application of the polyamic acid solution primer in a display substrate.

The technical scheme of the invention is as follows:

in order to achieve the above object, the present invention provides a method for preparing a polyamic acid solution primer, the method comprising: the polyamic acid solution and the silica nanoparticles are uniformly mixed to prepare the polyamic acid solution primer, wherein the polyamic acid solution primer can improve the heat resistance of the main body film, improve the adhesion of the main body film, and improve the material of the display substrate.

In some embodiments, the polyamic acid solution is produced by polymerizing a tetracarboxylic dianhydride monomer with a diamine monomer.

In some embodiments, the tetracarboxylic dianhydride monomer comprises 1,2,4, 5-pyromellitic dianhydride, and the diamine monomer comprises 4, 4' -oxydianiline.

In some embodiments, the polymerization further comprises a second tetracarboxylic dianhydride monomer, the mole percent of the second tetracarboxylic dianhydride monomer being less than 70%.

In some embodiments, the mole percentage of the second tetracarboxylic dianhydride monomer is less than 50%.

In some embodiments, the second tetracarboxylic dianhydride monomer is selected from the group consisting of 3,3 ', 4,4 ' -diphenyl ether dianhydride, 4,4 ' - (hexafluoroisopropylidene) diphthalic anhydride, 3 ', 4,4 ' -biphenyl tetracarboxylic dianhydride, 3 ', 4,4 ' -diphenylsulfone tetracarboxylic dianhydride, 4,4 ' - (4,4 ' -isopropylidene diphenoxy) diphthalic anhydride, 3 ', 4,4 ' -benzophenone tetracarboxylic dianhydride, and combinations thereof.

In some embodiments, the polymerization further comprises a second diamine monomer, and the mole percentage of the second diamine monomer is less than 99%.

In some embodiments, the second diamine monomer is selected from the group consisting of p-phenylenediamine, m-phenylenediamine, 3,4 '-diaminodiphenyl ether, 4' -diaminodiphenyl sulfone, 3 '-diaminodiphenyl ether, 2' -dimethyl-4, 4 '-diaminobiphenyl, 4' -diaminodiphenylmethane, 4 '-diaminobenzophenone, 4' -diaminodiphenyl-2, 2-hexafluoropropane, 9-bis- (4-aminophenyl) fluorene, 9-bis- (3-fluoro-4-aminophenyl) fluorene, 2 '-bis (trifluoromethyl) -4, 4' -diaminobiphenyl, bis- (2-trifluoromethyl-4-aminophenoxy) biphenyl, m-phenylenediamine, And combinations thereof.

In some embodiments, the polyamic acid solution is mixed with the silica nanoparticles at a ratio of greater than 0.1 and less than 7.

In some embodiments, the polyamic acid solution is prepared directly from the reaction of a tetracarboxylic dianhydride monomer and a diamine monomer.

In some embodiments, the polyamic acid solution is prepared by precipitation, drying, and redissolution after reacting a tetracarboxylic dianhydride monomer with a diamine monomer.

The invention also provides the polyamic acid solution primer prepared by the method.

In some embodiments, the solvent in the polyamic acid solution primer is selected from the group consisting of N, N-dimethylformamide, N-dimethylacetamide, N-methyl pyrrolidone, N-ethyl pyrrolidone, dimethyl sulfoxide, hexamethylphosphoramide, and combinations thereof.

The invention also provides a method for preparing a film by using the polyamic acid solution primer, which comprises the following steps:

(1) casting a polyamic acid solution primer on a glass substrate;

(2) drying to form a thin layer, and casting a main body film on the basis of the thin layer; and

(3) the heat treatment is performed according to the heat treatment condition of the main body film to obtain a thin film.

In some embodiments, the host film is a solution of polyamic acid, or other high performance resin. The subject film is not limited to the meaning of the subject film mentioned in the present invention.

In some embodiments, drying includes heating, and the thin layer is less than 10 microns thick.

In some embodiments, the thin layer is less than 5 microns thick.

In some embodiments, the method further comprises removing the solvent by heating, and casting the second host film.

In some embodiments, the method further comprises removing the solvent by heating, and after further heat treating, imidizing, heat treating, recasting the second host film.

In some embodiments, the nitrogen decomposition temperature of the film is 530 ℃.

The invention also provides application of the polyamic acid solution primer in a display substrate.

In some embodiments, the precipitating agent used in the precipitation operation is selected from the group consisting of water, isopropanol, methanol, ethanol, acetone, MIBK, and combinations thereof.

Has the advantages that:

the polyamic acid solution obtained by polymerizing the polymerization monomers had an apparent viscosity of 2000-15000 cps and a solid content of 10-30%. The polyamic acid solution primer disclosed by the invention is easy to process into a film, a main body film can be coated on the primer after the primer is coated and dried, and the film prepared after high-temperature heat treatment has good heat resistance and bonding performance. Therefore, the polyamic acid solution primer can improve the heat resistance of the main body film, improve the adhesiveness of the main body film, avoid the bubble defect, and is more suitable for being used as a material of a display substrate. The polyamic acid solution primer with excellent characteristics can be used for substrate pretreatment to manufacture flexible OLED devices.

Detailed Description

The invention will be illustrated below with reference to specific embodiments. It should be noted that the following examples are illustrative of the present invention, and are not intended to limit the present invention. Other combinations and various modifications within the spirit or scope of the present invention may be made without departing from the spirit or scope of the present invention.

The polyamic acid (precursor of polyimide) solution is an original solution obtained by polymerizing a polymerization monomer. Alternatively, the polyamic acid solution and the precipitant are mixed and soaked in a certain ratio under stirring, the precipitant and impurities are removed by filtration, and the polyamic acid solid obtained after drying is dissolved in a solvent in a certain ratio to obtain the polyamic acid solution with appropriate viscosity and solid content.

Unless otherwise stated, the viscosities in the present invention are bulk viscosities; the solid contents of the invention are all weight percentages.

The method for preparing the film by using the polyamic acid solution primer comprises the following steps: the polyamic acid solution primer is obtained by polymerizing monomers, then processing the monomers, and uniformly mixing the monomers with silicon dioxide nano particles. And casting the polyamide acid solution primer on a substrate to form a film, heating to remove the solvent, casting a main body film, and performing high-temperature heat treatment to finish the preparation of the film. The resulting polyamic acid solution primer can optimize the thermal decomposition temperature of the bulk film and the adhesion of the bulk film to the substrate by optimizing the mixing ratio of the monomers, polyamic acid solution, and silica nanoparticles used.

Representative dianhydride monomer examples of the present invention are as follows:

pyromellitic anhydride (PMDA);

biphenyl dianhydride (BPDA);

monoether dianhydride (ODPA);

hexafluorodianhydride (6 FDA);

diphenyl Sulfone Dianhydride (DSDA);

bisphenol a diether dianhydride (BisADA);

benzophenone dianhydride (BTDA), and the like.

Examples of representative diamine monomers in the present invention:

p-phenylenediamine (pPDA);

m-phenylenediamine (mPDA);

4, 4' -diaminodiphenyl ether (ODA);

3,4 '-diaminodiphenyl ether (3, 4' -ODA);

4, 4' -diaminodiphenyl sulfone (DDS);

3,3 '-diaminodiphenyl ether (3, 3' -DDS);

2,2 '-dimethyl-4, 4' -diaminobiphenyl (OTOL)

4, 4' -diaminodiphenylmethane (MDA);

4, 4' -diaminobenzophenone;

4, 4' -diaminodiphenyl-2, 2-hexafluoropropane;

9, 9-bis- (4-aminophenyl) fluorene;

9, 9-bis- (3-fluoro-4-aminophenyl) fluorene;

2,2 '-bis (trifluoromethyl) -4, 4' -diaminobiphenyl (PFMB);

bis- (2-trifluoromethyl-4-aminophenoxy) biphenyl, and the like.

In the polymerization process using the normal feeding sequence, the aromatic diamine is first dissolved in the solvent and the aromatic dianhydride is added to initiate the polymerization reaction. The solution viscosity increases as the polyamic acid is formed.

The test items in the following examples are as follows:

solid content test: calculating solid content according to the feeding;

and (3) testing the viscosity of the solution: the solution viscosity was measured at 30 ℃ using a Brookfield DV-I viscometer;

testing the film forming property: the sample solution was cast on a glass substrate, dried with hot air to remove the residual solvent, and then heated at high temperature (400-. The presence or absence of projections, inhomogeneities, cracks, powdering and the like was evaluated by observation;

and (3) testing thermal stability: thin film thermal stability was tested by thermogravimetric analysis (TGA) model TA-Q50, heating the sample from room temperature to 700 ℃ at a rate of 20 ℃/min under nitrogen atmosphere. It was determined that 1% weight loss corresponds to a temperature of T1% and 5% weight loss corresponds to a temperature of T5%.

Example 1

In a flask equipped with stirrer, stirring blade, nitrogen blanket and condenser was charged 83.67 g of NMP, 50 mmol of PMDA and 50 mmol of ODA. The reaction was then carried out at room temperature under a stream of nitrogen for 5 hours. The resulting reaction solution had an apparent viscosity of 2300 cps and a solid content of 20.0%. The DMAc solution of commercially available silica nanoparticles was mixed uniformly with the obtained reaction solution in a ratio of 40:60 to obtain a primer having a solid content of 20.0%.

The glass substrate was treated with a primer, the thickness of the coating film was controlled by a slit method, and a thin layer of 1 μm was obtained after drying. Then, the coating film thickness was controlled by a slit method using a solution of BPDA/PMDA/pda/ODA of 40/60/99.5/0.5 prepared in advance, and a film of 20 μm was obtained after drying and heat treatment. The film was laminated to the substrate with a T1% of 530 ℃ and a T5% of 587 ℃, which was significantly higher than the untreated substrate (see comparative example 1).

Example 2

In a flask equipped with stirrer, stirring blade, nitrogen blanket and condenser was charged 83.67 g of NMP, 50 mmol of PMDA and 50 mmol of ODA. The reaction was then carried out at room temperature under a stream of nitrogen for 5 hours. The resulting reaction solution had an apparent viscosity of 2300 cps and a solid content of 20.0%. The DMAc solution of commercially available silica nanoparticles was mixed uniformly with the obtained reaction solution in a ratio of 60:40 to obtain a primer having a solid content of 20.0%.

The glass substrate was treated with a primer, the thickness of the coating film was controlled by a slit method, and a thin layer of 1 μm was obtained after drying. Then, the coating film thickness was controlled by a slit method using a solution of BPDA/PMDA/pda/ODA of 40/60/99.5/0.5 prepared in advance, and a film of 20 μm was obtained after drying and heat treatment. The film was attached to the substrate with a T1% of 540 c and a T5% of 595 c, which is significantly higher than the untreated substrate (see comparative example 1).

Example 3

In a flask equipped with stirrer, stirring blade, nitrogen blanket and condenser, 76.48 g of NMP, 19.8 mmol of BPDA, 29.7 mmol of PMDA, 2.5 mmol of ODA and 47.5 mmol of pPDA were charged. The reaction was then carried out at room temperature under a stream of nitrogen for 5 hours. The resulting reaction solution had an apparent viscosity of 9120 cps and a solid content of 19.0%. The DMAc solution of commercially available silica nanoparticles was mixed uniformly with the resulting reaction solution in a ratio of 20:80 to obtain a primer with a solid content of 19.2%.

The glass substrate was treated with a primer, the thickness of the coating film was controlled by a slit method, and a thin layer of 1 μm was obtained after drying. Then, the thickness of the coating film was controlled by a slit method using a solution of BPDA/PMDA/pda/ODA 40/60/90/10 prepared in advance, and a film of 20 μm was obtained after drying and heat treatment. The film was laminated to the substrate with T1% of 533 ℃ and T5% of 586 ℃ which was significantly higher than the untreated substrate (see comparative example 2).

Example 4

In a flask equipped with stirrer, stirring blade, nitrogen blanket and condenser, 76.48 g of NMP, 19.8 mmol of BPDA, 29.7 mmol of PMDA, 2.5 mmol of ODA and 47.5 mmol of pPDA were charged. The reaction was then carried out at room temperature under a stream of nitrogen for 5 hours. The resulting reaction solution had an apparent viscosity of 9120 cps and a solid content of 19.0%. The DMAc solution of commercially available silica nanoparticles was mixed uniformly with the resulting reaction solution in a ratio of 40:60 to obtain a primer with a solid content of 19.4%.

The glass substrate was treated with a primer, the thickness of the coating film was controlled by a slit method, and a thin layer of 1 μm was obtained after drying. Then, the thickness of the coating film was controlled by a slit method using a solution of BPDA/PMDA/pda/ODA 40/60/90/10 prepared in advance, and a film of 20 μm was obtained after drying and heat treatment. The film was laminated to the substrate with a T1% of 534 ℃ and a T5% of 586 ℃ which was significantly higher than the untreated substrate (see comparative example 2).

Example 5

The glass substrate was treated with a primer, the thickness of the coating film was controlled by a slit method, and a thin layer of 1 μm was obtained after drying. Then, the thickness of the coating film was controlled by a slit method using a solution of BPDA/PMDA/pda 70/30/100 prepared in advance, and a film of 20 μm was obtained after drying and heat treatment. The film was laminated to the substrate with a T1% of 559 ℃ and a T5% of 600 ℃, whereas the comparative example did not use a polyamic acid solution primer and had blister defects.

Comparative example 1

A solution of BPDA/PMDA/pda/ODA of the above example of 40/60/99.5/0.5 was coated directly onto glass without the use of a primer to give a blister-free film. However, the thermal properties of the film were poor, with T1% being only 523 ℃ and T5% being 570 ℃.

Comparative example 2

A solution of BPDA/PMDA/pda/ODA of the above example, 40/60/90/10, was coated directly onto glass without the use of a primer to give a blister-free film. However, the thermal properties of the film are poor, with T1% being only 521 ℃ and T5% being 571 ℃.

Comparative example 3

The BPDA/PMDA/pda 70/30/100 solution in the above example was applied directly without using a primer, and the resulting film was peeled off, and a uniform film could not be obtained.

Referring to comparative examples 1 to 3, it can be seen from examples 1 to 5 above that the polyamic acid solution primer of the present invention is easily processed into a film, and the main body film can be coated thereon after coating and drying, and the film obtained after high temperature heat treatment has good heat resistance and adhesion. The polyamic acid solution primer provided by the invention can effectively improve the adhesive property and the thermal decomposition temperature of the main body film, avoids the foaming defect and is suitable for being used as a substrate material of a flexible display.

The above embodiments are merely illustrative of the technical concept and features of the present invention, and the present invention is not limited thereto, and equivalent changes and modifications made according to the spirit of the present invention should be covered thereby.

Claims

1. A method for preparing a polyamic acid solution primer, the method comprising: and uniformly mixing a polyamic acid solution and the silicon dioxide nano-particles to prepare the polyamic acid solution primer, wherein the polyamic acid solution primer can improve the heat resistance of the main body film, improve the adhesion of the main body film and improve the material of the display substrate.

2. The method of claim 1, wherein the polyamic acid solution is produced by polymerizing a tetracarboxylic dianhydride monomer and a diamine monomer.

3. The method of claim 2, wherein the tetracarboxylic dianhydride monomer comprises 1,2,4, 5-pyromellitic dianhydride and the diamine monomer comprises 4, 4' -oxydianiline.

4. The method of claim 2, wherein the polymerization further comprises a second tetracarboxylic dianhydride monomer having a mole percent of less than 70%.

5. The method of claim 4, wherein the mole percent of the second tetracarboxylic dianhydride monomer is less than 50%.

6. The method of claim 4, wherein the second tetracarboxylic dianhydride monomer is selected from the group consisting of 3,3 ', 4,4 ' -diphenyl ether dianhydride, 4,4 ' - (hexafluoroisopropylidene) diphthalic anhydride, 3 ', 4,4 ' -biphenyltetracarboxylic dianhydride, 3 ', 4,4 ' -diphenylsulfone tetracarboxylic dianhydride, 4,4 ' - (4,4 ' -isopropylidene diphenoxy) diphthalic anhydride, 3 ', 4,4 ' -benzophenonetetracarboxylic dianhydride, and combinations thereof.

7. The method of claim 2, wherein the polymerization further comprises a second diamine monomer having a mole percent of less than 99%.

8. The method of claim 7, wherein the second diamine monomer is selected from the group consisting of p-phenylenediamine, m-phenylenediamine, 3,4 '-diaminodiphenyl ether, 4' -diaminodiphenyl sulfone, 3 '-diaminodiphenyl ether, 2' -dimethyl-4, 4 '-diaminobiphenyl, 4' -diaminodiphenylmethane, 4 '-diaminobenzophenone, 4' -diaminodiphenyl-2, 2-hexafluoropropane, 9-bis- (4-aminophenyl) fluorene, 9-bis- (3-fluoro-4-aminophenyl) fluorene, 2 '-bis (trifluoromethyl) -4, 4' -diaminobiphenyl, bis- (2-trifluoromethyl-4-aminophenoxy) biphenyl, m-phenylenediamine, and combinations thereof.

9. The method of claim 1, wherein the polyamic acid solution is mixed with the silica nanoparticles at a ratio greater than 0.1 and less than 7.

10. The method of claim 1, wherein the polyamic acid solution is prepared directly from the reaction of a tetracarboxylic dianhydride monomer and a diamine monomer.

11. The method of claim 10, wherein the polyamic acid solution is prepared by reacting a tetracarboxylic dianhydride monomer with a diamine monomer, followed by precipitation, drying, and redissolution.

12. A polyamic acid solution primer prepared by the method of any one of the preceding claims.

13. The polyamic acid solution primer according to claim 12, wherein the solvent in the polyamic acid solution primer is selected from the group consisting of N, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, dimethyl sulfoxide, hexamethylphosphoramide, and combinations thereof.

14. A method for preparing a film using the polyamic acid solution primer according to claim 12 or 13, comprising:

(1) casting the polyamic acid solution primer on a glass substrate;

(3) and performing heat treatment according to the heat treatment condition of the main body film to obtain a thin film.

15. The method according to claim 14, wherein the host film is a solution of polyamic acid, or other high performance resin.

16. The method of claim 14, wherein the drying comprises heating and the thin layer is less than 10 microns thick.

17. The method of claim 16, wherein the thin layer is less than 5 microns thick.

18. The method of claim 14, wherein the method further comprises removing the solvent by heating and casting the second host film.

19. The method according to claim 14, wherein the method further comprises removing the solvent by heating, and further casting the second body film after heat treatment, imidization, heat treatment.

20. The method of claim 14, wherein the nitrogen decomposition temperature of the film is 530 ℃.

21. Use of the polyamic acid solution primer according to claim 12 or 13 in a display substrate.