Polyamide acid composition, polyimide, polyimide film and method for producing the same

Abstract

The present application discloses a kind of polyamide acid composition, polyimide, polyimide film and its preparation method.The present application provides a kind of polyamide acid composition, it includes the following components, polyamide acid and additive;The polymerization monomer of the polyamide acid includes diamine monomer and dianhydride monomer;The additive is one or several of methyl triethoxysilane, calcium stearate and zinc stearate, the mass ratio of the additive and the polymerization monomer is (0.1~15):100.The polyimide and polyimide film prepared by the polyamide acid composition provided by the present application have lower dielectric constant and dielectric loss, and also have lower water absorption, lower thermal expansion coefficient.

Description

Technical Field

[0001] This invention relates to the field of polyimide materials technology, specifically to a polyamic acid composition, polyimide, polyimide film, and a method for preparing the same. Background Technology

[0002] The development of 5G undoubtedly presents opportunities for the advancement and innovation of smartphone antennas. With the development of networks, the frequency of radio waves used in mobile communications is gradually increasing. Because electromagnetic waves have the characteristic that the higher the frequency, the shorter the wavelength, and the easier it is to attenuate in the propagation medium, the higher the frequency, the lower the loss requirement for antenna materials.

[0003] Early antennas were made of metals such as copper and alloys. Later, with the advent of flexible circuit board technology, 4G antennas began to use polyimide (PI) film. However, PI suffers from signal delay and distortion in high-frequency signal transmission at 10GHz, failing to meet the requirements of 5G terminals. LCP (Liquid Crystal Polymer) and MPI (Modified PI) materials, with their lower dielectric and conductor losses, are expected to stand out in the future 5G era.

[0004] LCP possesses excellent dielectric properties, with a dielectric constant of 2.9 and a dielectric loss of 0.002 at 10GHz. It also exhibits outstanding hygroscopicity, with a water absorption rate of less than 0.01%. However, LCP materials are expensive and have complex processes due to their high manufacturing difficulty and low yield. Currently, MPI, as a modified material for traditional PI flexible printed circuit boards, offers performance close to LCP in the frequency range below 15GHz, while being cheaper. MPI has significant advantages in terms of supply, production capacity, yield, and cost, and is expected to become one of the mainstream antenna materials in the early stages of the 5G era.

[0005] This places new demands on the dielectric properties of signal transmission materials, requiring the dielectric constant (Dk) of polyimide materials to be reduced from 3.5–4.0 to below 3.5, and the dielectric loss factor (Df) to be reduced from 0.4–0.01 to below 0.006, or even lower.

[0006] Currently, methods for modifying polyimide films include structural modification, filler modification, and blending modification. Filler modification mainly involves adding fluorinated particles (calcium fluoride, magnesium fluoride, potassium fluoride, PTFE, etc.) and hollow glass microspheres to reduce dielectric properties. Currently, patented filler contents are generally around 5%, and the uniformity of particle dispersion is difficult to control consistently. Amino-based surface treatments are often used for modification before adding to the polyimide system, resulting in a cumbersome process. Furthermore, the addition of large filler particles significantly reduces the mechanical properties of the film. Blending modification mainly involves blending with hydrocarbon resins, liquid crystal polymer (LCP) resins, and acrylic resins. However, this method may cause phase separation, leading to delamination and cracking of the molded film.

[0007] Therefore, by introducing fluorinated functional groups, large side groups, and alicyclic structures through structural design, the above difficulties can be overcome by reducing the dielectric properties of the film. However, these functional monomers are expensive. Fluorinated functional groups and large side groups have large molar volumes, which can effectively reduce the dielectric constant (Dk) of polyimide, but the large volume and loose molecular chain packing result in a large coefficient of thermal expansion (CTE) and dielectric loss (Df) of the film. In addition, in order to obtain good solubility and melt processing characteristics, end-capping agents are used during polymerization. The polyimide obtained by this method has a small molecular weight, resulting in poor mechanical properties of the film. Polyimide films cannot be used alone and can only be used by compounding with LCP, which is complex and has a low yield. Alicyclic structures are difficult to design, have fewer varieties, and have poor monomer activity. Polymerization is mostly carried out at high temperatures, which consumes a lot of energy and results in films with low heat resistance.

[0008] Currently, most patents address the high-frequency, high-speed material requirements of 5G by reducing the dielectric properties of materials. However, from a practical application perspective, besides the dielectric constant and dielectric loss, the hygroscopicity of materials has a significant impact on high-frequency, high-speed transmission. If the material has a high water absorption rate, the loss-frequency curve of the substrate shifts significantly before and after moisture absorption, resulting in substantial transmission loss. Furthermore, as a raw material for high-end flexible copper-clad laminates, it needs to maintain a similar coefficient of thermal expansion (CTE) to copper foil (approximately 18). Excessively high or low CTE values ​​can cause warping in the flexible copper-clad laminate. Therefore, achieving all these performance requirements simultaneously for polyimide materials suitable for high-frequency, high-speed flexible copper-clad laminates presents considerable challenges. Summary of the Invention

[0009] The technical problem to be solved by this invention is that polyimides in the prior art have high water absorption, and this invention provides a polyamic acid composition, polyimide, polyimide film, and a method for preparing the same. The polyimide and polyimide film provided by this invention have low dielectric constant and dielectric loss, as well as low water absorption and low coefficient of thermal expansion.

[0010] The present invention provides a polyamic acid composition comprising the following components: polyamic acid and additives; wherein the polymeric monomers of the polyamic acid include diamine monomers and dianhydride monomers, and the additives are one or more selected from methyltriethoxysilane, calcium stearate and zinc stearate, and the mass ratio of the additives to the polymeric monomers is (0.1-15):100.

[0011] Preferably, the diamine monomer comprises a flexible diamine monomer.

[0012] The flexible diamine monomer is a conventional flexible diamine monomer in the art, preferably one or more of 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 1,3-bis(4-aminophenoxy)benzene (TPE-R), 1,4-bis(4-aminophenoxy)benzene (TPE-Q), 4,4'-diaminodiphenyl ether (ODA), and 4,4'-diaminodiphenylmethane (MDA), more preferably ODA.

[0013] Preferably, the diamine monomer further includes one or more of benzimidazole diamine monomers and rigid diamine monomers.

[0014] Preferably, the structure of the benzimidazole diamine monomer contains two or more benzimidazole structural units, more preferably two benzimidazole structural units.

[0015] Preferably, the structure of the benzimidazole diamine monomer is shown in formula A2-I.

[0016]

[0017] in,

[0018] R 1 For NH2 or R 2 For NH2 or

[0019] Preferably, the benzimidazole diamine monomer is one or more of the following compounds:

[0020]

[0021]

[0022] Preferably, the benzimidazole diamine monomer is APBIA or BPBIA; more preferably, it is BPBIA.

[0023] The rigid diamine monomer is a conventional rigid diamine monomer in the art, preferably one or more of 4,4'-diamino-2,2'-dimethyl-1,1-biphenyl (MTA), 4,4'-bis(4-aminophenoxy)biphenyl (BAPB), 4-aminobenzoic acid-4-aminophenyl ester (APAB), 4,4'-bis-(3-aminophenoxy)biphenyl (BAPB-M), and p-phenylenediamine (PPD), more preferably PPD.

[0024] Preferably, the diamine monomer is any of the following:

[0025] Option 1: Composed of the aforementioned benzimidazole diamine monomer (e.g., BPBIA), the aforementioned flexible diamine monomer (e.g., ODA), and the aforementioned rigid diamine monomer (e.g., PPD);

[0026] Option 2: Composed of the aforementioned benzimidazole diamine monomer (e.g., APBIA or BPBIA) and the aforementioned flexible diamine monomer (e.g., ODA);

[0027] Option 3: The diamine monomer is the flexible diamine monomer (e.g., ODA).

[0028] Preferably, the dianhydride monomer comprises a dianhydride monomer containing an ester bond.

[0029] The dianhydride monomer containing ester bonds is a conventional dianhydride monomer containing ester bonds in the art, preferably...

[0030]

[0031] One or more of them, more preferably TAHQ.

[0032] Preferably, the dianhydride monomer further includes a dianhydride monomer that does not contain an ester bond.

[0033] The dianhydride monomer without ester bonds is a flexible dianhydride monomer and / or a rigid dianhydride monomer, preferably a rigid dianhydride monomer.

[0034] The rigid dianhydride monomer is a conventional rigid dianhydride monomer in the art, preferably one or more of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA), cyclobutanetetracarboxylic dianhydride (CBDA), and 1,2,4,5-cyclohexanetetracarboxylic dianhydride (CHDA), more preferably BPDA and / or PMDA.

[0035] The flexible dianhydride monomer is a conventional flexible dianhydride monomer in the art, preferably one or more of 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride (ODPA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), or 3,3',4,4'-diphenyl sulfone dianhydride (DSDA), more preferably ODPA.

[0036] Preferably, the dianhydride monomer is composed of a rigid dianhydride monomer (e.g., PMDA or BPDA) and a dianhydride monomer containing an ester bond (e.g., TAHQ).

[0037] Preferably, the polymeric monomer is composed of a dianhydride monomer and a diamine monomer.

[0038] Preferably, the additive is calcium stearate and / or zinc stearate.

[0039] Preferably, the polyamic acid composition further includes a solvent.

[0040] The solvent is a conventional solvent in the art, preferably an aprotic polar solvent, more preferably one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc) or N-methylpyrrolidone (NMP), and more preferably DMF.

[0041] Preferably, the polyamic acid composition comprises polyamic acid, additives, and solvents.

[0042] The molar ratio of the diamine monomer to the dianhydride monomer can be 0.95:1 to 1.05:1, preferably 1:1.

[0043] Preferably, in the diamine monomer, the benzimidazole diamine monomer accounts for less than 55% of the total content of the diamine monomer, calculated based on the total molar number of the diamine monomer as 100%.

[0044] Preferably, the diamine monomer, calculated based on the total molar number of the diamine monomer as 100%, comprises the following components in molar percentage: 20% to 100% flexible diamine monomer, 0% to 55% benzimidazole diamine monomer, and 0% to 45% rigid diamine monomer; the sum of the contents of each component is 100%.

[0045] In the diamine monomer, the molar percentage of the flexible diamine monomer is preferably 30% to 100% (e.g., 30%, 40%, 45%, 50%, 55%, 60%, or 100%), and more preferably 30% to 55%.

[0046] In the diamine monomer, the molar percentage of the benzimidazole diamine monomer is preferably 10% to 50% (e.g., 10%, 20%, 25%, 40%, 45%, or 50%), more preferably 20% to 50%.

[0047] In the diamine monomer, the molar percentage of the rigid diamine monomer is preferably 0-30%, for example, 0, 10%, 20%, 25% or 30%.

[0048] Preferably, in the dianhydride monomer, based on the total molar number of dianhydride monomers being 100%, the dianhydride monomers containing ester bonds account for more than 30% of the total content of the dianhydride monomers, more preferably more than 50%.

[0049] Preferably, the dianhydride monomer comprises, with the total molar number of dianhydride monomers being 100%, the following molar percentages of components: 0% to 70% of dianhydride monomers without ester bonds and 30% to 100% of dianhydride monomers containing ester bonds; the sum of the contents of each component is 100%.

[0050] In the dianhydride monomers described herein, the molar percentage of the dianhydride monomers without ester bonds is preferably 25% to 70%, for example, 25%, 40%, 45%, 50%, or 70%; more preferably, 25% to 50%.

[0051] In the dianhydride monomer, the molar percentage of the dianhydride monomer containing ester bonds is preferably 30% to 75%, for example 30%, 50%, 55%, 60% or 75%, more preferably 50% to 75%.

[0052] The preferred mass ratio of the additive to the polymeric monomer is (0.1-5):100, for example, 0.5:100, 2:100, 3:100 or 4:100.

[0053] When the polyamic acid composition further includes a solvent, the mass ratio of the solvent to the polymeric monomer can be (1-10):1, preferably (2-5):1, for example 3:1 or 4:1.

[0054] When the polyamic acid composition further includes a solvent, the total solids mass percentage in the polyamic acid composition may be 10% to 35%, preferably 20% to 25%, for example 20%, 22% or 25%, where the total solids mass refers to the sum of the masses of the components other than the solvent.

[0055] When the polyamic acid composition further includes a solvent, the viscosity of the polyamic acid composition can be 30 poise to 5000 poise, preferably 1500 poise to 4000 poise, for example 1800 poise, 2500 poise, 2600 poise, 2700 poise, 2800 poise, 2900 poise, 3000 poise or 3500 poise.

[0056] Preferably, the polyamic acid composition is one of the following:

[0057] Option 1: The polyamic acid composition comprises a solvent, polyamic acid, and additives;

[0058] The mass ratio of the additive to the polymeric monomer is 2:100;

[0059] The diamine monomer is composed of the following molar percentage components: 50% ODA and 50% APBIA; the dianhydride monomer is composed of the following molar percentage components: 50% TAHQ and 50% PMDA.

[0060] Option 2: The polyamic acid composition comprises a solvent, polyamic acid, and additives;

[0061] The mass ratio of the additive to the polymeric monomer is 2:100;

[0062] The diamine monomer is composed of the following molar percentage components: 55% ODA and 45% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 55% TAHQ and 45% BPDA.

[0063] Option 3: The polyamic acid composition comprises a solvent, polyamic acid, and additives;

[0064] The mass ratio of the additive to the polymeric monomer is 4:100;

[0065] The diamine monomer is composed of the following molar percentage components: 50% ODA and 50% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 55% TAHQ and 45% BPDA.

[0066] Option 4: The polyamic acid composition comprises a solvent, polyamic acid, and additives;

[0067] The mass ratio of the additive to the polymeric monomer is 4:100;

[0068] The diamine monomer is composed of the following molar percentage components: 45% ODA, 10% PPD and 45% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 55% TAHQ and 45% PMDA.

[0069] Option 5: The polyamic acid composition comprises a solvent, polyamic acid, and additives;

[0070] The mass ratio of the additive to the polymeric monomer is 2:100;

[0071] The diamine monomer is composed of the following molar percentage components: 40% ODA, 20% PPD and 40% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 60% TAHQ and 40% BPDA.

[0072] Option 6: The polyamic acid composition comprises a solvent, polyamic acid, and additives;

[0073] The mass ratio of the additive to the polymeric monomer is 2:100;

[0074] The diamine monomer is composed of the following molar percentage components: 50% ODA, 30% PPD, and 20% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 60% TAHQ and 40% BPDA.

[0075] Option 7: The polyamic acid composition comprises a solvent, polyamic acid, and additives;

[0076] The mass ratio of the additive to the polymeric monomer is 3:100;

[0077] The diamine monomer is composed of the following molar percentage components: 45% ODA, 30% PPD and 25% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 75% TAHQ and 25% PMDA.

[0078] Option 8: The polyamic acid composition comprises a solvent, polyamic acid, and additives;

[0079] The mass ratio of the additive to the polymeric monomer is 3:100;

[0080] The diamine monomer is composed of the following molar percentage components: 30% ODA, 25% PPD and 45% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 75% TAHQ and 25% PMDA.

[0081] Option 9: The polyamic acid composition comprises a solvent, polyamic acid, and additives;

[0082] The mass ratio of the additive to the polymeric monomer is 2:100;

[0083] The diamine monomer is composed of the following molar percentage components: 100% ODA; the dianhydride monomer is composed of the following molar percentage components: 50% TAHQ and 50% PMDA.

[0084] Option 10: The polyamic acid composition comprises a solvent, polyamic acid, and additives;

[0085] The mass ratio of the additive to the polymeric monomer is 0.5:100;

[0086] The diamine monomer is composed of the following molar percentage components: 60% ODA, 30% PPD and 10% APBIA; the dianhydride monomer is composed of the following molar percentage components: 55% TAHQ and 45% BPDA.

[0087] Option 11: The polyamic acid composition comprises a solvent, polyamic acid, and additives;

[0088] The mass ratio of the additive to the polymeric monomer is 0.5:100;

[0089] The diamine monomer is composed of the following molar percentage components: 40% ODA, 40% PPD, and 20% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 75% TAHQ and 25% PMDA.

[0090] Option 12: The polyamic acid composition comprises a solvent, polyamic acid, and additives;

[0091] The mass ratio of the additive to the polymeric monomer is 2:100;

[0092] The diamine monomer is composed of the following molar percentage components: 40% ODA, 20% PPD and 40% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 30% TAHQ and 70% PMDA.

[0093] The present invention provides a method for preparing the polyamic acid composition as described above, which includes the following steps: mixing the components as described above to obtain the polyamic acid composition.

[0094] Preferably, the method for preparing the polyamic acid composition further includes the following steps: pre-polymerizing the polymeric monomers as described above in a solvent to obtain the polyamic acid; and mixing the polyamic acid with the additives to obtain the polyamic acid composition.

[0095] The reaction temperature of the pre-condensation reaction is the conventional reaction temperature for such reactions in the art, preferably -15℃ to 50℃, more preferably -5℃ to 5℃, for example 0℃.

[0096] The prepolymerization reaction is preferably carried out under an inert atmosphere, and more preferably under a nitrogen atmosphere.

[0097] The reaction time of the pre-condensation reaction is the conventional reaction time for such reactions in the art, preferably 8h to 12h, more preferably 6h to 8h, for example 6h or 8h.

[0098] The additive is preferably mixed with the polyamic acid in the form of an additive mixture solution.

[0099] The solvent in the additive mixture solution may be the same as or different from the solvent in the polyamic acid.

[0100] The solvent of the additive mixture solution is a conventional solvent for such reactions in the art, preferably an aprotic polar solvent, more preferably one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc) or N-methylpyrrolidone (NMP), and more preferably DMF.

[0101] The amount of solvent used in the additive mixture is sufficient to allow the additive to be uniformly dispersed in the solvent. Preferably, the mass ratio of the additive to the solvent is (1-6):1, more preferably (2-5):1, for example 2:1, 3:1, 4:1 or 5:1.

[0102] The mixing time between the polyamic acid and the additive is sufficient to allow the additive to be uniformly dispersed in the polyamic acid. Preferably, the mixing time is 1 hour to 5 hours, more preferably 1 hour to 3 hours, for example, 1 hour, 2 hours or 3 hours.

[0103] The present invention provides a polyimide prepared by an imidization reaction of a polyamic acid composition as described above.

[0104] The present invention provides a method for preparing polyimide as described above, which includes the following steps: performing an imidization reaction on the polyamic acid composition as described above to obtain polyimide.

[0105] The imidization reaction can be a thermal imidization reaction or a chemical imidization reaction, preferably a chemical imidization reaction.

[0106] When the imidization reaction is a chemical imidization reaction, the raw materials in the preparation method of the polyimide also include a dehydrating agent and a catalyst.

[0107] The dehydrating agent may be an organic acid anhydride, preferably acetic anhydride and / or formic anhydride, such as acetic anhydride.

[0108] The mass ratio of the polyamic acid composition to the dehydrating agent can be (1-50):1, preferably (10-30):1, for example 12:1, 15:1, 17:1, 19:1 or 21:1.

[0109] The catalyst may be one or more of triethylamine, pyridine, isoquinoline and methylpyridine, such as pyridine or 3-methylpyridine.

[0110] The mass ratio of the polyamic acid composition to the catalyst can be (50-200):1, preferably (80-150):1, for example 90:1, 100:1, 110:1 or 140:1.

[0111] The reaction temperature of the imidization reaction is the conventional reaction temperature for such reactions in the art, preferably 100℃ to 450℃, for example 150℃, 160℃, 200℃, 250℃, 300℃, 350℃ or 400℃.

[0112] Preferably, the method for preparing the polyimide further includes the method for preparing the polyamic acid composition as described above.

[0113] The present invention provides a polyimide film obtained by film formation of the polyimide as described above; or obtained by film-forming imidization treatment of the polyamic acid composition as described above.

[0114] This invention provides a method for preparing a polyimide film as described above, which is one of the following methods:

[0115] Method 1: It includes the following steps, as described above, to form a polyimide film to obtain a polyimide thin film.

[0116] Method 2: It includes the following steps: the polyamic acid composition described above is subjected to film-forming imidization treatment to obtain a polyimide film.

[0117] Preferably, in the second method, the film-forming imidization includes a film-forming step and an imidization reaction step, and the conditions and operation of the imidization reaction are as described above.

[0118] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0119] The reagents and raw materials used in this invention are all commercially available.

[0120] The positive and progressive effects of this invention are as follows: the polyimide and polyimide film provided by this invention have low dielectric constant and dielectric loss, as well as low water absorption and low coefficient of thermal expansion, which is comparable to that of copper foil, thus meeting the main performance indicators of materials for high-frequency and high-speed applications. Detailed Implementation

[0121] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0122] When preparing polyimide films using the process described in the following examples, there is no limitation on the thickness of the polyimide film, which can be between 10 and 125 μm. For ease of performance comparison, the polyimide films prepared in the following examples and comparative examples have a thickness of approximately 25 μm.

[0123] The polyimide resin and film prepared in the examples were subjected to performance tests according to the following methods:

[0124] (1) Dielectric constant (Dk) and dielectric loss (Df): The sample to be tested was saturated with moisture for more than 3 days at room temperature. The test method was the coaxial resonant cavity method, and the instrument was the Anritsu vector network analyzer of Japan, which was tested at a frequency of 10 GHz.

[0125] (2) Coefficient of thermal expansion (CTE): Tested using a thermomechanical analyzer, specifically the TMA Q400 from TA Instruments, USA. Test temperature range: 50-200℃, heating rate: 10℃ / minute.

[0126] (3) Water absorption rate: The test method is in accordance with ASTM D570 98. The water absorption rate is calculated by accurately measuring the mass change of the film before and after immersing it in deionized water at 25°C for 24 hours.

[0127] (4) Dynamic viscosity: The test was conducted using a cone-plate viscometer from Brookfield, USA, at a temperature of 25°C.

[0128] The structural formulas corresponding to the abbreviations of the compounds in Examples 1 to 8 below are shown below.

[0129]

[0130] Example 1

[0131] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 10g of diamine monomer ODA and 11.2g of 2-(4-aminophenyl)-5-aminobenzimidazole (APBIA) were dissolved in 176g of DMF. After complete dissolution, 22.9g of TAHQ and 10.9g of PMDA were added in batches at 0°C. The funnel and reactor walls were rinsed with 40g of DMF to ensure that the dianhydride was completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution. 1.1g of calcium stearate dispersed in 4g of DMF was added to the above solution, and stirring was continued for 1 hour to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 2500 poise.

[0132] Take 30g of polyamic acid solution, add 1.4g of acetic anhydride and 0.22g of pyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 150℃ for 10min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature oven, heat and oriented at 350℃ for 60min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 1.

[0133] Example 2

[0134] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 11g of diamine monomer ODA and 18.7g of 2,2′-bis(4-aminophenyl)-5,5′-bibenzimidazole (BPBIA) were dissolved in 218g of DMF. After complete dissolution, 25.2g of TAHQ and 13.2g of BPDA were added in batches at -5°C. The funnel and reactor walls were rinsed with 50g of DMF to ensure that the dianhydride was completely added to the reaction system. The reaction was stirred for 8 hours under a nitrogen atmosphere to obtain a polyamic acid solution. 1.4g of zinc stearate dispersed in 4g of DMF was added to the above solution, and stirring was continued for 2 hours to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 1800 poise.

[0135] Take 30g of polyamic acid solution, add 1.6g of acetic anhydride and 0.28g of pyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 150℃ for 10min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature oven, heat and oriented at 360℃ for 50min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 1.

[0136] Example 3

[0137] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 10g of diamine monomers ODA and 20.8g of BPBIA were dissolved in 189g of DMF. After complete dissolution, 25.2g of TAHQ and 13.2g of BPDA were added in batches at -5℃. The funnel and reactor walls were rinsed with 50g of DMF to ensure that the dianhydrides were completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution. 2.8g of calcium stearate dispersed in 5g of DMF was added to the above solution, and stirring was continued for 3 hours to obtain a polyamic acid solution with a solid content of 22% and a viscosity of 3000 poise.

[0138] Take 30g of polyamic acid solution, add 2.5g of acetic anhydride and 0.35g of 3-methylpyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 150℃ for 10min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature oven, heat and oriented at 400℃ for 60min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 1.

[0139] Example 4

[0140] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 9g of diamine monomers ODA, 1.1g of PPD, and 18.7g of BPBIA were dissolved in 200g of DMF. After complete dissolution, 25.2g of TAHQ and 9.8g of PMDA were added in batches at -5℃. The funnel and reactor walls were rinsed with 45g of DMF to ensure that the dianhydrides were completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution. 2.5g of calcium stearate dispersed in 6g of DMF was added to the above solution, and stirring was continued for 2 hours to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 2600 poise.

[0141] Take 30g of polyamic acid solution, add 2.5g of acetic anhydride and 0.3g of 3-methylpyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 160℃ for 12min to obtain a self-supporting gel film; peel the gel film from the metal steel plate and fix it on the metal frame, put it in a high temperature drying oven, heat and oriented at 350℃ for 40min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 1.

[0142] Example 5

[0143] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 8g of diamine monomers ODA, 2.16g of PPD, and 16.64g of BPBIA were dissolved in 211g of DMF. After complete dissolution, 27.5g of TAHQ and 11.8g of BPDA were added in batches at 0°C. The funnel and reactor walls were rinsed with 48g of DMF to ensure that the dianhydrides were completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution. 1.3g of calcium stearate dispersed in 6g of DMF was added to the above solution, and stirring was continued for 2 hours to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 2700 poise.

[0144] Take 30g of polyamic acid solution, add 1.8g of acetic anhydride and 0.32g of 3-methylpyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 160℃ for 10min to obtain a self-supporting gel film; peel the gel film from the metal steel plate and fix it on the metal frame, put it in a high temperature drying oven, heat and oriented at 400℃ for 60min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 1.

[0145] Example 6

[0146] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 10g of diamine monomers ODA, 3.2g of PPD, and 8.3g of BPBIA were dissolved in 194g of DMF. After complete dissolution, 27.5g of TAHQ and 11.8g of BPDA were added in batches at -5°C. The funnel and reactor walls were rinsed with 44g of DMF to ensure that the dianhydrides were completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution. 1.2g of calcium stearate dispersed in 5g of DMF was added to the above solution, and stirring was continued for 2 hours to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 2600 poise.

[0147] Take 30g of polyamic acid solution, add 1.4g of acetic anhydride and 0.32g of 3-methylpyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 150℃ for 10min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature drying oven, heat and oriented at 400℃ for 60min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 1.

[0148] Example 7

[0149] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 9g of diamine monomers ODA, 3.2g of PPD, and 10.4g of BPBIA were dissolved in 138g of DMF. After complete dissolution, 34.4g of TAHQ and 5.5g of PMDA were added in batches at -5℃. The funnel and reactor walls were rinsed with 45g of DMF to ensure that the dianhydrides were completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution. 1.9g of calcium stearate dispersed in 5g of DMF was added to the above solution, and stirring was continued for 2 hours to obtain a polyamic acid solution with a solid content of 25% and a viscosity of 3500 poise.

[0150] Take 30g of polyamic acid solution, add 2.5g of acetic anhydride and 0.27g of 3-methylpyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 160℃ for 12min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature drying oven, heat and oriented at 350℃ for 50min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 1.

[0151] Example 8

[0152] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 6g of diamine monomers ODA, 2.7g of PPD, and 18.7g of BPBIA were dissolved in 215g of DMF. After complete dissolution, 34.4g of TAHQ and 5.5g of PMDA were added in batches at -5℃. The funnel and reactor walls were rinsed with 48g of DMF to ensure that the dianhydrides were completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution. 2g of calcium stearate dispersed in 5g of DMF was added to the above solution, and stirring was continued for 2 hours to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 2600 poise.

[0153] Take 30g of polyamic acid solution, add 2.5g of acetic anhydride and 0.3g of 3-methylpyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 160℃ for 12min to obtain a self-supporting gel film; peel the gel film from the metal steel plate and fix it on the metal frame, put it in a high temperature drying oven, heat and oriented at 350℃ for 40min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 1.

[0154] Example 9

[0155] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 20g of diamine monomer ODA was dissolved in 189g of DMF. After complete dissolution, 22.9g of TAHQ and 10.9g of PMDA were added in batches at 0°C. The funnel and reactor walls were rinsed with 40g of DMF to ensure that the dianhydride was completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution. 1.1g of calcium stearate dispersed in 4g of DMF was added to the above solution, and stirring was continued for 1 hour to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 2600 poise.

[0156] Take 30g of polyamic acid solution, add 1.4g of acetic anhydride and 0.22g of pyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 150℃ for 10min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature drying oven, heat and oriented at 350℃ for 60min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 2.

[0157] Example 10

[0158] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 12g of diamine monomers ODA, 3.3g of PPD, and 2.3g of APBIA were dissolved in 179g of DMF. After complete dissolution, 25.2g of TAHQ and 13.2g of BPDA were added in batches at 0°C. The funnel and reactor walls were rinsed with 40g of DMF to ensure that the dianhydrides were completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution. 0.8g of calcium stearate dispersed in 5g of DMF was added to the above solution, and stirring was continued for 1 hour to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 2800 poise.

[0159] Take 30g of polyamic acid solution, add 2.0g of acetic anhydride and 0.33g of 3-methylpyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 150℃ for 10min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature drying oven, heat and oriented at 350℃ for 60min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 2.

[0160] Example 11

[0161] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and nitrogen inlet / outlet. 8g of diamine monomers ODA, 4.3g of PPD, and 8.3g of BPBIA were dissolved in 193g of DMF. After complete dissolution, 34.5g of TAHQ and 5.5g of PMDA were added in batches at -5℃. The funnel and reactor walls were rinsed with 43g of DMF to ensure that the dianhydrides were completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution. 1.2g of calcium stearate dispersed in 5g of DMF was added to the above solution, and stirring was continued for 1 hour to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 2900 poise.

[0162] Take 30g of polyamic acid solution, add 2.5g of acetic anhydride and 0.32g of pyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 150℃ for 10min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature drying oven, heat and oriented at 350℃ for 60min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 2.

[0163] Example 12

[0164] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and nitrogen inlet / outlet. 8g of diamine monomers ODA, 2.16g of PPD, and 16.64g of BPBIA were dissolved in 211g of DMF. After complete dissolution, 19.3g of TAHQ and 17.7g of BPDA were added in batches at 0°C. The funnel and reactor walls were rinsed with 48g of DMF to ensure that the dianhydrides were completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution. 1.3g of calcium stearate dispersed in 6g of DMF was added to the above solution, and stirring was continued for 2 hours to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 2700 poise.

[0165] Take 30g of polyamic acid solution, add 1.8g of acetic anhydride and 0.32g of 3-methylpyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 160℃ for 10min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature drying oven, heat and oriented at 400℃ for 60min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 2.

[0166] Comparative Example 1

[0167] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 10g of diamine monomer ODA was dissolved in 189g of DMF. After complete dissolution, 22.9g of TAHQ and 10.9g of PMDA were added in batches at 0°C. The funnel and reactor walls were rinsed with 40g of DMF to ensure that the dianhydride was completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 2600 poise.

[0168] Take 30g of polyamic acid solution, add 1.4g of acetic anhydride and 0.22g of pyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 150℃ for 10min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature drying oven, heat and oriented at 350℃ for 60min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 3.

[0169] Comparative Example 2

[0170] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 20g of diamine monomer ODA was dissolved in 180g of DMF. After complete dissolution, 45.8g of TAHQ was added at -5℃. The funnel and reactor walls were rinsed with 48g of DMF to ensure that the dianhydride was completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution with a solid content of 22% and a viscosity of 2900 poise.

[0171] Take 30g of polyamic acid solution, add 1.4g of acetic anhydride and 0.22g of pyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 160℃ for 10min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature drying oven, heat and oriented at 350℃ for 60min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 3.

[0172] Comparative Example 3

[0173] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 10.8 g of diamine monomer PPD was dissolved in 160 g of DMF. After complete dissolution, 27.5 g of TAHQ and 11.8 g of BPDA were added in batches at -5 °C. The funnel and reactor walls were rinsed with 40 g of DMF to ensure that the dianhydride was completely added to the reaction system. The reaction was stirred for 6 h under a nitrogen atmosphere to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 3200 poise.

[0174] Take 30g of polyamic acid solution, add 1.8g of acetic anhydride and 0.28g of pyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 150℃ for 10min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature oven, heat and oriented at 350℃ for 60min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 3.

[0175] Comparative Example 4

[0176] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 16g of diamine monomer ODA and 2.2g of PPD were dissolved in 205g of DMF. After complete dissolution, 21.8g of PMDA was added in batches at -5℃. The funnel and reactor walls were rinsed with 47g of DMF to ensure that the dianhydride was completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution with a solid content of 21% and a viscosity of 3800 poise.

[0177] Take 30g of polyamic acid solution, add 1.8g of acetic anhydride and 0.21g of pyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 150℃ for 10min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature drying oven, heat and oriented at 350℃ for 60min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 3.

[0178] Comparative Example 5

[0179] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 8g of diamine monomer ODA and 25.0g of BPBIA were dissolved in 225g of DMF. After complete dissolution, 11.5g of TAHQ and 16.4g of PMDA were added in batches at -5℃. The funnel and reactor walls were rinsed with 47g of DMF to ensure that the dianhydrides were completely added to the reaction system. The reaction was stirred for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution with a solid content of 22% and a viscosity of 3400 poise.

[0180] Take 30g of polyamic acid solution, add 2.5g of acetic anhydride and 0.32g of pyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 150℃ for 10min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature drying oven, heat and oriented at 350℃ for 60min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 3.

[0181] Comparative Example 6

[0182] Nitrogen gas was introduced into a reactor equipped with a mechanical stirrer and a nitrogen inlet / outlet. 10g of diamine monomer ODA and 11.2g of 2-(4-aminophenyl)-5-aminobenzimidazole (APBIA) were dissolved in 176g of DMF. After complete dissolution, 22.9g of TAHQ and 10.9g of PMDA were added in batches at 0°C. The funnel and reactor walls were rinsed with 40g of DMF to ensure that the dianhydride was completely added to the reaction system. The reaction was stirred for 6h under a nitrogen atmosphere to obtain a polyamic acid solution. 9.35g of calcium stearate dispersed in 4g of DMF was added to the above solution, and stirring was continued for 1h to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 2500 poise.

[0183] Take 30g of polyamic acid solution, add 1.4g of acetic anhydride and 0.22g of pyridine to the polyamic acid solution, stir evenly at room temperature and degas, and treat at 150℃ for 10min to obtain a self-supporting gel film; peel the gel film off the metal steel plate and fix it on the metal frame, put it in a high temperature drying oven, heat and oriented at 350℃ for 60min to obtain a polyimide film, and perform performance tests on the film. The results are shown in Table 3.

[0184] Table 1: Examples 1-8 and their film properties

[0185]

[0186]

[0187] Table 2: Examples 9-12 and their film properties

[0188]

[0189] Table 3: Comparative Examples 1-6 and their Thin Film Properties

[0190]

[0191] Table 4: Performance parameters of DuPont commercial films

[0192] commodity Dielectric constant Dielectric loss Water absorption rate DuPont 370LK 3.6 0.0054 1.0％

[0193] Table 5: Dielectric properties of polyimide film before and after moisture absorption in Example 4

[0194] Dielectric constant Dielectric loss dry state 2.9 0.0024 Saturated moisture absorption 3.0 0.0030 .

Claims

1. A polyamic acid composition, characterized in that, It comprises the following components: polyamic acid and additives; the polymeric monomer of the polyamic acid is composed of dianhydride monomer and diamine monomer, and the additive is one or more of methyltriethoxysilane, calcium stearate and zinc stearate, and the mass ratio of the additive to the polymeric monomer is (0.1~5):

100. The dianhydride monomer is composed of a rigid dianhydride monomer and a dianhydride monomer containing an ester bond. The dianhydride monomer containing ester bonds is: , and One or more of them; The rigid dianhydride monomer is BPDA and / or PMDA; The diamine monomer is any of the following schemes: Option 1: Composed of benzimidazole diamine monomers, flexible diamine monomers, and rigid diamine monomers; Option 2: Composed of benzimidazole diamine monomers and flexible diamine monomers; The benzimidazole diamine monomer is one or more of the following compounds. 、 、 ； The flexible diamine monomer is ODA; The rigid diamine monomer is one or more of 4,4'-diamino-2,2'-dimethyl-1,1-biphenyl (MTA), 4,4'-bis(4-aminophenoxy)biphenyl (BAPB), 4-aminobenzoic acid-4-aminophenyl ester (APAB), 4,4'-di-(3-aminophenoxy)biphenyl (BAPB-M), and p-phenylenediamine (PPD).

2. The polyamic acid composition according to claim 1, characterized in that, It meets one or more of the following conditions, (1) The additives are calcium stearate and / or zinc stearate; (2) The polyamic acid composition further includes a solvent; (3) The molar ratio of the diamine monomer to the dianhydride monomer is 0.95:1 to 1.05:1; (4) The mass ratio of the additive to the polymer monomer is 0.5:100, 2:100, 3:100 or 4:

100.

3. The polyamic acid composition according to claim 2, characterized in that, The molar ratio of the diamine monomer to the dianhydride monomer is 1:

1.

4. The polyamic acid composition according to claim 2, characterized in that, It meets one or more of the following conditions, (1) The dianhydride monomer containing ester bonds is TAHQ; (2) The solvent is an aprotic polar solvent; (3) The polyamic acid composition comprises polyamic acid, additives and solvents; (4) Of the diamine monomers, the benzimidazole diamine monomers account for less than 55% of the total content of the diamine monomers; (5) Of the dianhydride monomers, the dianhydride monomers containing ester bonds account for more than 30% of the total content of the dianhydride monomers; (6) The mass ratio of the solvent to the polymer monomer is (1~10):1; (7) When the polyamic acid composition further includes a solvent, the total solids in the polyamic acid composition have a mass percentage of 10% to 35%; (8) When the polyamic acid composition further includes a solvent, the viscosity of the polyamic acid composition is 30 poise to 5000 poise.

5. The polyamic acid composition according to claim 4, characterized in that, It meets one or more of the following conditions, (1) The rigid diamine monomer is PPD; (2) The solvent is one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc) or N-methylpyrrolidone (NMP); (3) Of the dianhydride monomers, the dianhydride monomers containing ester bonds account for more than 50% of the total content of the dianhydride monomers; (4) The mass ratio of the solvent to the polymer monomer is (2~5):1; (5) When the polyamic acid composition further includes a solvent, the total solids in the polyamic acid composition have a mass percentage of 20% to 25%; (6) When the polyamic acid composition further includes a solvent, the viscosity of the polyamic acid composition is 1500 poise to 4000 poise.

6. The polyamic acid composition according to claim 5, characterized in that: The benzimidazole diamine monomer is APBIA or BPBIA; Alternatively, the solvent may be DMF; Alternatively, the mass ratio of the solvent to the polymeric monomer is 3:1 or 4:1; Alternatively, when the polyamic acid composition further includes a solvent, the total solids percentage in the polyamic acid composition is 20%, 22%, or 25% by mass; Alternatively, when the polyamic acid composition further includes a solvent, the viscosity of the polyamic acid composition is 1800 poise, 2500 poise, 2600 poise, 2700 poise, 2800 poise, 2900 poise, 3000 poise, or 3500 poise.

7. The polyamic acid composition according to claim 1, characterized in that: The benzimidazole diamine monomer is BPBIA.

8. The polyamic acid composition according to claim 4, characterized in that, It meets one or more of the following conditions, (1) The diamine monomer comprises the following components in molar percentage: 20%~60% flexible diamine monomer, 10~55% benzimidazole diamine monomer and 0~45% rigid diamine monomer; the sum of the contents of each component is 100%; (2) The dianhydride monomers mentioned herein include the following components in molar percentage: 25% to 70% rigid dianhydride monomers and 30% to 75% dianhydride monomers containing ester bonds; the sum of the contents of each component is 100%.

9. The polyamic acid composition according to claim 8, characterized in that, The diamine monomer is composed of BPBIA, ODA and PPD; Alternatively, the diamine monomer is composed of the benzimidazole diamine monomer and ODA; the benzimidazole diamine monomer is APBIA or BPBIA; Alternatively, the dianhydride monomer is composed of a rigid dianhydride monomer and TAHQ, wherein the rigid dianhydride monomer is PMDA or BPDA; Alternatively, in the diamine monomer, the molar percentage of the flexible diamine monomer is 30% to 60%; Alternatively, the molar percentage of the benzimidazole diamine monomer in the diamine monomer is 10% to 50%; Alternatively, the molar percentage of the rigid diamine monomer in the diamine monomer is 0-30%.

10. The polyamic acid composition according to claim 9, characterized in that, In the diamine monomer, the molar percentage of the flexible diamine monomer is 30%~55%; Alternatively, the molar percentage of the benzimidazole diamine monomer in the diamine monomer is 20% to 50%; Alternatively, in the diamine monomer, the molar percentage of the rigid diamine monomer is 0, 10%, 20%, 25%, or 30%; Alternatively, in the dianhydride monomer, the molar percentage of the rigid dianhydride monomer is 25% to 50%; Alternatively, in the dianhydride monomer, the molar percentage of the dianhydride monomer containing ester bonds is 50% to 75%.

11. The polyamic acid composition according to claim 9, characterized in that, In the diamine monomer, the molar percentage of the flexible diamine monomer is 30%, 40%, 45%, 50%, 55%, or 60%. Alternatively, in the diamine monomer, the molar percentage of the benzimidazole diamine monomer is 10%, 20%, 25%, 40%, 45%, or 50%; Alternatively, in the dianhydride monomer, the molar percentage of the rigid dianhydride monomer is 25%, 40%, 45%, 50%, or 70%; Alternatively, the molar percentage of the dianhydride monomer containing ester bonds in the dianhydride monomer is 30%, 50%, 55%, 60%, or 75%.

12. The polyamic acid composition according to claim 8, characterized in that, The polyamic acid composition is one of the following schemes: Option 1: The polyamic acid composition comprises a solvent, polyamic acid, and additives; The mass ratio of the additive to the polymeric monomer is 2:100; The diamine monomer is composed of the following molar percentage components: 50% ODA and 50% APBIA; the dianhydride monomer is composed of the following molar percentage components: 50% TAHQ and 50% PMDA. Option 2: The polyamic acid composition comprises a solvent, polyamic acid, and additives; The mass ratio of the additive to the polymeric monomer is 2:100; The diamine monomer is composed of the following molar percentage components: 55% ODA and 45% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 55% TAHQ and 45% BPDA. Option 3: The polyamic acid composition comprises a solvent, polyamic acid, and additives; The mass ratio of the additive to the polymeric monomer is 4:100; The diamine monomer is composed of the following molar percentage components: 50% ODA and 50% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 55% TAHQ and 45% BPDA. Option 4: The polyamic acid composition comprises a solvent, polyamic acid, and additives; The mass ratio of the additive to the polymeric monomer is 4:100; The diamine monomer is composed of the following components in molar percentage: 45% ODA, 10% PPD and 45% BPBIA; the dianhydride monomer is composed of the following components in molar percentage: 55% TAHQ and 45% PMDA. Option 5: The polyamic acid composition comprises a solvent, polyamic acid, and additives; The mass ratio of the additive to the polymeric monomer is 2:100; The diamine monomer is composed of the following components in molar percentage: 40% ODA, 20% PPD and 40% BPBIA; the dianhydride monomer is composed of the following components in molar percentage: 60% TAHQ and 40% BPDA. Option 6: The polyamic acid composition comprises a solvent, polyamic acid, and additives; The mass ratio of the additive to the polymeric monomer is 2:100; The diamine monomer is composed of the following components in molar percentage: 50% ODA, 30% PPD and 20% BPBIA; the dianhydride monomer is composed of the following components in molar percentage: 60% TAHQ and 40% BPDA. Option 7: The polyamic acid composition comprises a solvent, polyamic acid, and additives; The mass ratio of the additive to the polymeric monomer is 3:100; The diamine monomer is composed of the following molar percentage components: 45% ODA, 30% PPD and 25% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 75% TAHQ and 25% PMDA. Option 8: The polyamic acid composition comprises a solvent, polyamic acid, and additives; The mass ratio of the additive to the polymeric monomer is 3:100; The diamine monomer is composed of the following molar percentage components: 30% ODA, 25% PPD and 45% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 75% TAHQ and 25% PMDA. Option 9: The polyamic acid composition comprises a solvent, polyamic acid, and additives; The mass ratio of the additive to the polymeric monomer is 0.5:100; The diamine monomer is composed of the following components in molar percentage: 60% ODA, 30% PPD and 10% APBIA; the dianhydride monomer is composed of the following components in molar percentage: 55% TAHQ and 45% BPDA. Option 10: The polyamic acid composition comprises a solvent, polyamic acid, and additives; The mass ratio of the additive to the polymeric monomer is 0.5:100; The diamine monomer is composed of the following molar percentage components: 40% ODA, 40% PPD, and 20% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 75% TAHQ and 25% PMDA. Option 11: The polyamic acid composition comprises a solvent, polyamic acid, and additives; The mass ratio of the additive to the polymeric monomer is 2:100; The diamine monomer is composed of the following molar percentage components: 40% ODA, 20% PPD, and 40% BPBIA; the dianhydride monomer is composed of the following molar percentage components: 30% TAHQ and 70% PMDA.

13. A method for preparing a polyamic acid composition according to any one of claims 1 to 12, characterized in that, It includes the following steps, The components as described in any one of claims 1 to 12 are mixed to obtain a polyamic acid composition.

14. The method for preparing the polyamic acid composition according to claim 13, characterized in that, The method for preparing the polyamic acid composition, wherein The method includes the following steps: in a solvent, pre-condensing the polymeric monomer as described in any one of claims 1 to 12 to obtain the polyamic acid; and mixing the polyamic acid with the additive to obtain the polyamic acid composition.

15. The method for preparing the polyamic acid composition according to claim 14, characterized in that, The reaction temperature of the pre-condensation reaction is -15℃ to 50℃; Alternatively, the pre-condensation reaction is carried out under an inert atmosphere; Alternatively, the reaction time of the pre-condensation reaction is 8h~12h; Alternatively, the additive may be mixed with the polyamic acid in the form of an additive mixture solution, wherein the solvent of the additive mixture solution is an aprotic polar solvent. Alternatively, the mixing time may be 1 to 5 hours.

16. The method for preparing the polyamic acid composition according to claim 15, characterized in that, The reaction temperature for the pre-condensation reaction is -5℃ to 5℃; Alternatively, the pre-condensation reaction is carried out under a nitrogen atmosphere; The reaction time for the pre-condensation reaction is 6 to 8 hours. Alternatively, the solvent of the additive mixture solution is one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), or N-methylpyrrolidone (NMP). Alternatively, in the additive mixture solution, the mass ratio of the additive to the solvent is (1~6):1; The mixing time is 1 hour to 3 hours.

17. The method for preparing the polyamic acid composition according to claim 16, characterized in that, The reaction temperature of the pre-condensation reaction is 0°C; Alternatively, the solvent for the additive mixture solution is DMF; Alternatively, in the additive mixture solution, the mass ratio of the additive to the solvent is (2~5):1; The mixing time is 1 hour, 2 hours, or 3 hours.

18. The method for preparing the polyamic acid composition according to claim 17, characterized in that, In the additive mixture solution, the mass ratio of the additive to the solvent is 2:1, 3:1, 4:1, or 5:

1.

19. A polyimide, characterized in that, It is prepared by imidization reaction of the polyamic acid composition as described in any one of claims 1 to 12.

20. A method for preparing polyimide as described in claim 19, characterized in that, It includes the following steps, The polyamic acid composition according to any one of claims 1 to 12 is subjected to an imidization reaction to obtain a polyimide.

21. The method for preparing polyimide according to claim 20, characterized in that, It meets one or more of the following conditions, (1) The iminoization reaction is a thermal iminoization reaction or a chemical iminoization reaction; When the imidization reaction is a chemical imidization reaction, the raw materials in the preparation method of the polyimide also include a dehydrating agent and a catalyst; The dehydrating agent is an organic acid anhydride; the mass ratio of the polyamic acid composition to the dehydrating agent is (1~50):1; The catalyst is one or more of triethylamine, pyridine, isoquinoline, and methylpyridine; The mass ratio of the polyamic acid composition to the catalyst is (50~200):1; (2) The reaction temperature of the imidization reaction is 100℃~450℃; (3) The method for preparing the polyimide further includes the method for preparing the polyamic acid composition as described in any one of claims 13-18.

22. The method for preparing polyimide according to claim 21, characterized in that, The iminoization reaction described is a chemical iminoization reaction. Alternatively, the dehydrating agent may be acetic anhydride and / or formic anhydride; Alternatively, the mass ratio of the polyamic acid composition to the dehydrating agent is (10~30):1; Alternatively, the catalyst may be pyridine or 3-methylpyridine; Alternatively, the mass ratio of the polyamic acid composition to the catalyst is (80~150):1; Alternatively, the reaction temperature of the imidization reaction is 150°C, 160°C, 200°C, 250°C, 300°C, 350°C, or 400°C.

23. The method for preparing polyimide according to claim 22, characterized in that, The dehydrating agent is acetic anhydride; Alternatively, the mass ratio of the polyamic acid composition to the dehydrating agent is 12:1, 15:1, 17:1, 19:1, or 21:1; Alternatively, the mass ratio of the polyamic acid composition to the catalyst is 90:1, 100:1, 110:1, or 140:

1.

24. A polyimide film, characterized in that, It is obtained by film formation of polyimide as described in claim 19; or by film-forming imidization treatment of polyamic acid composition as described in any one of claims 1 to 12.

25. A method for preparing a polyimide film as described in claim 24, characterized in that, It is one of the following methods, Method 1: It includes the following steps: obtaining a polyimide film by forming a polyimide film as described in claim 19; Method 2: It includes the following steps: the polyamic acid composition as described in any one of claims 1 to 12 is subjected to a film-forming imidization treatment to obtain a polyimide film.

26. The method for preparing the polyimide film according to claim 25, characterized in that, In the second method, the film-forming imidization includes a film-forming step and an imidization reaction step, and the conditions and operation of the imidization reaction are as described in any one of claims 21-23.

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