CN-119978367-B - Black polyimide film and preparation method thereof

Abstract

The invention relates to the field of organic materials, in particular to a black polyimide film and a preparation method thereof. The black polyimide film provided by the invention has a structure shown in a formula (L). The preparation method comprises the steps of adopting aniline oligomer diamine shown in a formula (II), coupling a protective group such as benzyloxycarbonyl and tert-butoxycarbonyl on each bridging nitrogen atom, carrying out homopolymerization or copolymerization on the diamine monomer shown in a formula (III) and a dianhydride monomer to form a resin solution, preparing a polyimide/polyamide acid film through a film forming process, and carrying out deprotection treatment to obtain the intrinsic black polyimide film. The polymer prepared by the invention has excellent dissolution performance, and meanwhile, after deprotection, the material shows uniform black property, excellent solvent resistance and mechanical property, and solves the contradiction between the processing performance, the solvent resistance and the mechanical property.

Inventors

• CAI YANCHUN
• QI FULING
• LIU FANGFANG
• JIAO LONG
• DAI XUEMIN
• WANG HANFU
• QIU XUEPENG

Assignees

• 中国科学院长春应用化学研究所

Dates

Publication Date

20260508

Application Date

20250221

Claims (8)

1. 1. The preparation method of the black polyimide film is characterized by comprising the following steps of: A) Mixing dianhydride monomer, diamine monomer and solvent, and performing polymerization reaction to obtain polyamic acid precursor solution; B) And (3) film preparation: then, the polyimide powder is dissolved in a solvent, cast into a film, dried and deprotected to obtain a black polyimide film; Wherein: The dianhydride monomer is 4,4' -terephthaloyl diphthalic anhydride or hexafluorodianhydride; the diamine monomer is a diamine monomer shown in a formula (II), or is a diamine monomer shown in the formula (II) and 4,4' -diaminodiphenyl ether; formula (II); in formula (II): n is 3-8; selected from the following groups: , 。
2. 2. The method according to claim 1, wherein in the step A), the molar ratio of the diamine monomer represented by the formula (II) to the 4,4' -diaminodiphenyl ether is 10:0 to 1:9.
3. 3. The method according to claim 1, wherein in the step A), the molar ratio of the diamine monomer to the dianhydride monomer is 1: (0.95-1.05).
4. 4. The method according to claim 1, wherein in the step a), the solvent comprises at least one of N, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, m-cresol, methylene chloride, chloroform, tetrahydrofuran, dioxane, acetone, butanone, toluene, ethyl acetate, xylene, diethyl ether.
5. 5. The method according to claim 1, wherein in the step a), the polymerization reaction is carried out at a temperature of-20 to 40 ℃ for a time of 1 to 70 hours.
6. 6. The method according to claim 1, wherein in the step B), the imidization is chemical imidization, which comprises mixing the polyamic acid precursor solution with an imidizing agent, followed by precipitation in a poor solvent, solid-liquid separation, and drying to obtain polyimide powder.
7. 7. The method according to claim 6, wherein the imidizing agent is a nitrogen-containing compound and acetic anhydride, wherein the nitrogen-containing compound is at least one of triethylamine, pyridine and picoline; The molar ratio of the nitrogen-containing compound to the diamine monomer used in the step A) is (0.5-3.5) to 1; The molar ratio of the acetic anhydride to the diamine monomer used in the step A) is (0.5-5.5) to 1.
8. 8. The method of claim 1, wherein in step B), the deprotecting group treatment is a chemical or heat treatment; the temperature of the heat treatment method is 140-250 ℃ and the time is 4-12 hours.

Description

Black polyimide film and preparation method thereof Technical Field The invention relates to the field of organic materials, in particular to a black polyimide film and a preparation method thereof. Background In recent years, the iteration speed of products in the communication industry is continuously increased, and the flexible display can greatly save the occupied space of equipment by virtue of the unique advantages of screen storage and expansion, so that the flexible display is favored by the market. Polyimide film is used as an important high-temperature resistant insulating material, and has good compatibility with copper foil, so that the polyimide film is widely applied in the field. However, as technology rapidly evolves, industry competition is increasing, protecting intellectual property and technical achievements is a necessary choice for enterprises. The skilled artisan has found that when using conventional yellow transparent polyimide films as the cover film, the printed wiring design is extremely vulnerable to cracking and duplication. To cope with this problem, many manufacturers have begun to use black polyimide films instead of conventional transparent polyimide films. In the high-end fields such as aerospace, in order to ensure the stable operation of an imaging system, a sensor and other sensitive devices, the devices are required to be prevented from being interfered by stray light, and the devices are usually placed in a light-shielding tool. With the continuous progress of aerospace technology, the requirements on the performance of the light-shielding tool are higher and higher, such as strong absorption capacity in a visible light region, light weight, excellent space resistance and the like. Accordingly, many technicians have begun exploring the use of black polyimide films to make such tooling. Meanwhile, in order to meet the preparation requirements of complex parts and respond to the development trend of low carbon and environmental protection, the market also puts more stringent demands on the solubility and the processability of materials. In summary, the market demand for black polyimide films is on the rise. The development of the black polyimide film with excellent optical shielding, mechanical and processing properties has wide market prospect and further contains far-reaching strategic significance. At present, the black polyimide film is mainly prepared by 3 methods, namely an in-situ dyeing method, namely adding additives such as black pigment or dye particles into a polyimide solution, and then adopting a film forming process to prepare a target film, namely a compounding method, namely a black resin is coated on the polyimide film and is cured by heating to obtain the black film, and the third is an intrinsic method, namely adding a special monomer into a polyimide system, wherein the introduced structure has stronger absorption in a visible light region. The patent CN109867786B selects 4 '-bis (4-amino anilino) benzene and 1,3' -bis (4-amino anilino) phenylenediamine monomers as diamine monomers, 3', 4' -Benzophenone Tetracarboxylic Dianhydride (BTDA), 3', 4' -diphenyl ether tetracarboxylic dianhydride (ODPA) and 3,3', one or more of 4,4' -biphenyl tetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA) are used as dianhydride monomers to polymerize in aprotic polar solvent to obtain polyamic acid solution, and then the black polyimide film is obtained through casting, coating and heat curing. The intrinsic black polyimide film has good electrical insulation performance, and can be applied to black polyimide protective films with high requirements on insulation performance, such as wireless charging antenna insulation protective films, FPC (flexible printed circuit) cover films, lithium battery connecting sheet cover films and the like, and black high-temperature resistant labels, black polyimide base films for adhesive tapes, solar energy absorption energy storage films and the like. Patent CN109180936a was prepared from pyromellitic dianhydride (PMDA), 4 '-diaminodiphenyl ether (ODA) and 4,4' -diaminodiphenylamine (NDA) as raw materials by a high-temperature imidization method. The performance test results show that the black polyimide film shows excellent light shielding property. The anthraquinone derivative quaternary amine monomer is selected in the patent CN113563212B, and only two amine groups in the monomer can be subjected to polycondensation reaction, so that a linear polymer can be obtained. The black polyimide obtained by the invention has good shading performance, good mechanical property, thermal stability and dielectric property, and the optical transmittance of all wave bands is less than 1%. Patent CN111574426a synthesizes a dark red or black isoindigo structure containing diamine monomer. The monomer (other diamine can be added) and aromatic dianhydride are subjected to polycondensation reaction to obtain a polyamic acid solution