Photosensitive polyimide resin purification method and photosensitive polyimide resin

Abstract

The invention relates to a purification method of photosensitive polyimide resin, which is characterized in that a photosensitive polyimide resin mass production purification process route corresponding to the optimal performance is developed by limiting potential process elements and various process element parameters in the process and combining the photoetching performance and a small molecule volatile matter (outgas) test result, and the photosensitive polyimide resin is produced according to the process. And the product stability and the yield are higher.

Description

Technical Field

[0001] The present invention relates to polyimide resins, specifically to the field of photosensitive polyimides, and particularly to a method and application for the purification process of photosensitive polyimide resins. Background Art

[0002] As a special engineering material, photosensitive polyimide (PSPI) has good thermal stability, mechanical properties, electrical properties, chemical corrosion resistance and other properties. It has been widely used in electronic device fields such as OLED flat panel displays and semiconductors, and is one of the organic polymer materials with the best comprehensive performance.

[0003] The market demand for photosensitive polyimide resin products is increasing day by day, and it is urgent to promote the research of photosensitive polyimide resins from the laboratory stage to the mass production stage. The problem is that during the process of research and development turning to mass production, due to scale limitations, many important potential process elements have not been verified, and there are many uncertain factors in data analysis. The mass-produced products of photosensitive polyimide resins have low repeatability, poor stability between batches, and low yield. The occurrence of these problems is related to the mismatch of the purification process of the synthesized products. Therefore, at present, the development of high-quality and stable mass-production processes for photosensitive polyimide resins still faces great challenges. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for the purification process of photosensitive polyimide resins. Through in-depth research, the inventors found that the purification process involves operations such as slurrying, filtration, and centrifugation. Changes in process parameters such as the temperature of the process medium, stirring frequency, feeding speed, filter bag mesh number, centrifugation time and speed, and the number of slurrying and centrifugation cycles directly affect the lithography performance of the product and the residual amount of small molecules in the resin powder, and thus affect the final performance of the purified product. By optimizing specific conditions, the present invention provides a method for the purification process of photosensitive polyimide resins that can produce products meeting the qualified performance requirements and have high stability between batches.

[0005] In addition, the present invention also found that the performance of photosensitive polyimide resins can be simplified to obtain (small molecule volatiles) outgas data through testing, and then combined with the sensitivity data to determine whether the performance meets the requirements. Therefore, based on the qualified outgas and sensitivity, the present invention can screen out the purification process route corresponding to the best performance for photosensitive polyimide resins. Specifically, the present invention provides a method for purifying photosensitive polyimide resins, which is characterized by including a slurrying process and a separation and liquid removal process.

[0006] In the beating process, the prepolymer of photosensitive polyimide is added to the beating kettle at a feeding rate of 1-2.4 L / min, the medium temperature is set at 0-40 °C, and beating is carried out for 5-50 minutes. Further preferably, the feeding rates are 1-1.5 L / min, 1-1.6 L / min, 1-1.7 L / min, 1-1.8 L / min, 1-1.9 L / min, 1-2.0 L / min, 1-2.2 L / min, 1-2.3 L / min, 1-2.4 L / min, and further preferably, the medium temperatures are 0-18 °C, 0-19 °C, 0-20 °C, 0-21 °C;

[0007] The condition is that the beating process and the separation and dewatering process are cycled 5-8 times to obtain the purified photosensitive polyimide resin, preferably cycled 5-7 times, and further preferably cycled 5-6 times.

[0008] In a preferred embodiment of the present invention, the separation and dewatering includes centrifugal dewatering. The parameters of centrifugal dewatering are that the centrifuge speed is 300-1500 rpm / min, and the filter bag specification is 400-1000 mesh. Further preferably, the centrifuge speed is 400-1000 rpm / min, and the filter bag specification is 500-800 mesh; nitrogen pressure filtration dewatering, the positive pressure is 0.08 MPa-0.1 MPa; vacuum suction filtration dewatering, the negative pressure is -0.1 MPa--0.08 MPa; the separation and dewatering preferably adopts centrifugal dewatering; after single separation and dewatering, the solid-liquid ratio is 1:3-1:2.5.

[0009] In a preferred embodiment of the present invention, in the centrifugal dewatering process, the centrifuge speed is 300-1500 rpm / min, which can be 300 rpm / min, 400 rpm / min, 500 rpm / min, 600 rpm / min, 700 rpm / min, 800 rpm / min, 900 rpm / min, 1000 rpm / min, 1100 rpm / min, 1200 rpm / min, 1300 rpm / min, 1400 rpm / min, 1500 rpm / min, and the filter bag specification is 400-1000 mesh, which can be 400 mesh, 500 mesh, 600 mesh, 700 mesh, 800 mesh, 900 mesh, 1000 mesh.

[0010] In a preferred embodiment of the present invention, the medium in the beating process is a mixed solution of a solvent and water, and the boiling point range of the solvent is 50 °C-250 °C under 0.1 MPa standard atmospheric pressure. Preferably, the medium in the beating process is a solvent that can be miscible with water in any proportion.

[0011] In a preferred embodiment of the present invention, the solvent in the medium during the beating process may be selected from one or a mixture of several of N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide, isopropanol, ethanol, and methanol.

[0012] In a preferred embodiment of the present invention, the medium in the beating process is a mixed solution of N-methylpyrrolidone and water.

[0013] In a preferred embodiment of the present invention, the medium in the beating process is a mixed solution of N-methylpyrrolidone and water with a ratio of 1:7 to 1:9.

[0014] In a preferred embodiment of the present invention, the stirring frequency in the beating process is 35 - 100 Hz, and it can be 35 Hz, 40 Hz, 45 Hz, 50 Hz, 55 Hz, 60 Hz, 65 Hz, 70 Hz, 75 Hz, 80 Hz, 85 Hz, 85 Hz, 90 Hz, 95 Hz, 100 Hz. Preferably, it is 30 - 50 Hz.

[0015] The molecular weight of the purified photosensitive polyimide resin is 2000 - 100000; the preferred molecular weight is 5000 - 50000, and the more preferred molecular weight is 6000 - 30000.

[0016] In a preferred embodiment of the present invention, the prepolymer of the photosensitive polyimide is a prepolymer of polyimide formed by 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and 3,3,4,4-dipropyl ether tetracarboxylic dianhydride.

[0017] In a preferred embodiment of the present invention, the prepolymer of the polyimide is prepared by the following process: N-methylpyrrolidone, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 3,3,4,4-dipropyl ether tetracarboxylic dianhydride, and an auxiliary agent are placed in a reaction kettle at 0 - 50 °C and kept at a constant temperature for 3 - 10 h. After the reaction is completed, filtration is carried out to obtain a prepolymer solution of the photosensitive polyimide. The prepolymer solution of the photosensitive polyimide is dried to obtain the prepolymer of the photosensitive polyimide.

[0018] The method adopted in the present invention is a method for purifying photosensitive polyimide resin. It conducts a combined study on the important process elements in the resin purification beating and centrifugation stages, and screens out a purification method suitable for the stable production of high-quality photosensitive polyimide resin. The present invention develops potential process elements and defines new process elements. The development of this process method can quickly and effectively screen out photosensitive polyimide resins with excellent performance, good batch-to-batch stability and repeatability, and achieve the stable mass production of high-quality photosensitive polyimide resin. Detailed Embodiments

[0019] The following details each element of the present invention.

[0020] The production of photosensitive polyimide resin generally consists of three processes: resin synthesis, resin purification, and resin drying.

[0021] The purification method of the present invention can be used for the purification of various photosensitive polyimide resins. The photosensitive polyimide resin can be obtained by a conventional method from a tetracarboxylic anhydride component and a diamine component. For the performance of the photosensitive polyimide resin, it can be appropriately composed of polyimides selected from aromatic compounds and alicyclic compounds. As the tetracarboxylic component, it is selected from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane, pyromellitic acid, 3,3',4,4'-benzophenone tetracarboxylic acid, 3,3,4,4-dipropyl ether tetracarboxylic anhydride, 3,3',4,4'-biphenyltetracarboxylic acid, 2,3,3',4'-biphenyltetracarboxylic acid, 4,4'-oxybisphthalic acid, bis(3,4-dicarboxyphenyl)sulfone, m-terphenyl-3,4,3',4'-tetracarboxylic acid, p-terphenyl-3,4,3',4'-tetracarboxylic acid, 1,2,3,4-cyclobutanetetracarboxylic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, [1,1'-bis(cyclohexane)]-3,3',4,4'-tetracarboxylic acid, [1,1'-bis(cyclohexane)]-2,3,3',4'-tetracarboxylic acid, [1,1'-bis(cyclohexane)]-2,2',3,3'-tetracarboxylic acid, octahydro-s-indacene-1,3,4,6-tetracarboxylic acid, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic acid, 6-(carboxymethyl)bicyclo[2.2.1]heptane-2,3,5-tricarboxylic acid, bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic acid, bicyclo[2.2.2]oct-5-ene-2,3,7,8-tetracarboxylic acid, tricyclo[4.2.2.02,5]decane-3,4,7,8-tetracarboxylic acid, tricyclo[4.2.2.02,5]dec-7-ene-3,4,9,10-tetracarboxylic acid, 9-oxatricyclo[4.2.1.02,5]nonane-3,4,7,8-tetracarboxylic acid, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2”-norbornane 5,5”,6,6”-tetracarboxylic acid, (4arH,8acH)-decahydro-1t,4t:5c,8c-dimethanonaphthalene-2c,3c,6c,7c-tetracarboxylic acid, (4arH,8acH)-decahydro-1t,4t:5c,8c-dimethanonaphthalene-2t,3t,6c,7c-tetracarboxylic acid and their derivatives such as tetracarboxylic dianhydrides, tetracarboxylic silyl esters, tetracarboxylic esters, and tetracarboxylic acid chlorides.

[0022] Examples of the diamine component include p-phenylenediamine, m-phenylenediamine, benzidine, 3,3'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)biphenylamine, 3,3'-bis(trifluoromethyl)biphenylamine, m-xylidine, 4,4'-diaminobenzanilide, 3,4'-diaminobenzanilide, N,N'-bis(4-aminophenyl)terephthalamide, N,N'-p-phenylenebis(p-aminobenzamide), 4-aminophenoxy-4-diaminobenzoate, bis(4-aminophenyl)terephthalate, biphenyl-4,4'-dicarboxylic acid bis(4-aminophenyl)ester, p-phenylenebis(p-aminobenzoate), bis(4-aminophenyl)-[1,1'-biphenyl]-4,4'-dicarboxylate, [1,1'-biphenyl]-4,4'-diylbis(4-aminobenzoate), 4,4'-oxydianiline, 3,4'-oxydianiline, 3,3'-oxydianiline, p-methylenebis(aniline), 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, bis(4-aminophenyl)sulfone, 3,3'-bis(trifluoromethyl)biphenylamine, 3,3'-bis((aminophenoxy)phenyl)propane, 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, bis(4-(4-aminophenoxy)diphenyl)sulfone, bis(4-(3-aminophenoxy)diphenyl)sulfone, octafluorobenzidine, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 2,4-bis(4-aminophenylamino)-6-amino-1,3,5-triazine, 2,4-bis(4-aminophenylamino)-6-methylamino-1,3,5-triazine, 2,4-bis(4-aminophenylamino)-6-ethylamino-1,3,5-triazine, 2,4-bis(4-aminophenylamino)-6-anilino-1,3,5-triazine, 1,4-diaminocyclohexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, 1,4-diamino-2-n-propylcyclohexane, 1,4-diamino-2-isopropylcyclohexane, 1,4-diamino-2-n-butylcyclohexane, 1,4-diamino-2-isobutylcyclohexane, 1,4-diamino-2-sec-butylcyclohexane, 1,4-diamino-2-tert-butylcyclohexane, 1,2-diaminocyclohexane, 1,3-diaminocyclobutane, 1,4-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, diamino bicycloheptane, diamino methyl bicycloheptane, diaminooxy bicycloheptane, diamino methoxy bicycloheptane, and the diamine component of isophorone diamine.The diamine component can be used alone or in combination of two or more.

[0023] The synthesis of the photosensitive polyimide can be carried out by the direct method. In a solvent, diamine and dianhydride are added, and then an auxiliary agent is added, and the photosensitive polyimide is obtained through their contact reaction. As the solvent, water is preferably used; amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, etc.; cyclic ester solvents such as γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ-butyrolactone, etc.; carbonate solvents such as ethylene carbonate, propylene carbonate, etc.; glycol solvents such as triethylene glycol, etc.; phenolic solvents such as m-cresol, p-cresol, 3-chlorophenol, 4-chlorophenol, etc.; acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide, etc. Further, other conventional organic solvents can also be used, namely phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2-methyl cellosolve acetate, ethyl cellosolve acetate, butyl acetate cellosolve, tetrahydrofuran, dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, terpene, mineral essential oil, petroleum naphtha-based solvent, etc. It should be noted that two or more solvents can also be used in combination.

[0024] It can contain, according to needs, chemical imidization agents (acid anhydrides such as acetic anhydride, amine compounds such as pyridine, isoquinoline, etc.), antioxidants, fillers (inorganic particles such as silica, etc.), dyes, pigments, coupling agents such as silane coupling agents, undercoatings, flame retardants, defoamers, leveling agents, rheology control agents (flow aids), release agents, ultraviolet absorbers, etc.

[0025] A typical prepolymer of the photosensitive polyimide of the present invention is a prepolymer of polyimide formed by 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and 3,3,4,4-dipropyl ether tetracarboxylic dianhydride. For example, the prepolymer of the polyimide is prepared by the following process: N-methylpyrrolidone, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 3,3,4,4-dipropyl ether tetracarboxylic dianhydride and N,N-dimethylformamide dimethyl acetal are placed in a reaction kettle at 0-50°C and kept at a constant temperature for 3-10 h. After the reaction is completed, the prepolymer solution of the photosensitive polyimide is obtained by filtration, and the prepolymer solution of the photosensitive polyimide is dried to obtain the prepolymer of the photosensitive polyimide. This prepolymer is the ideal raw material for the purification process of the present invention.

[0026] The chemical material of photosensitive polyimide is difficult to be purified by means of crystallization, chromatography, extraction, etc. of small molecules. Through in-depth research, the inventors of the present invention found that a cyclic process including a beating and separation process has a very good effect on obtaining photosensitive polyimide with good performance.

[0027] The specific technological elements of the beating process include the temperature of the first precipitation medium (abbreviated as the medium temperature), the stirring frequency of the first precipitation (also abbreviated as the stirring frequency), and the feeding speed of the first precipitation (also abbreviated as the feeding speed);

[0028] The beating operation is an operation for purification by utilizing the solubility difference between the product and the impurities in the solvent (also called the medium in the present invention). Usually, the poor solvent of the product and the good solvent of the impurities are used for beating. If the solubility of the impurities is poor, recrystallization operation can be considered. When beating, the solid particles should be ground into as fine particles as possible (usually called Trituration in English) to dissolve out as many impurities as possible. In the present invention, heating can be carried out during beating, or beating can be carried out at room temperature. However, for solids with relatively low melting points, heating is preferably not carried out. During the beating process, the main substances dissolved out by the solvent are impurities. The required product has only poor solubility, not completely insoluble. Therefore, there is a dissolution / precipitation equilibrium process during the beating process. Therefore, if a suitable solvent is found for beating, the product purity can be increased to more than 99%. The beating operation is simple, and the product recovery rate during the whole process is higher than that of recrystallization. It is a very efficient purification method. The usual beating operation is suspension stirring and filtration (centrifugal dewatering). The usual operation is to select a suitable solvent (medium, which can be a mixed solvent). The solvent must have a small solubility for the product and a very good solubility for the impurities. Otherwise, the purification effect is not obvious or the product loss is large. The crude product is suspended in the selected solvent, and it is best to grind the solid into as fine particles as possible to increase the contact area between the impurities and the solvent and facilitate the dissolution of the impurities; stir the mixture, and select magnetic stirring or mechanical stirring according to the amount. After a certain period of time, filter to obtain the solid. In the present invention, the centrifugal dewatering process is used; wash the filter cake with as little beating solvent as possible, and washing after cooling the solvent can reduce the loss of the product.

[0029] The beating process is preferably combined with a low medium temperature, a high stirring frequency, and a low feeding speed; these conditions greatly affect the polymer granulation level. If the granulation degree is too poor, it is difficult to dissolve and remove the impurities. However, if the granulation is too fine, it may affect the later yield and process time.

[0030] In the beating process, the prepolymer of photosensitive polyimide is added to the beating kettle at a feeding speed of 1-2 L / min, the medium temperature is set at 0-15 °C, and beating is carried out for 5-50 minutes;

[0031] In the centrifugal dewatering process, a filter bag with 600 - 900 mesh is selected, and the centrifugal speed is set at 300 - 1500 rpm / min;

[0032] The condition is that the beating process and the centrifugal dewatering process are cycled 5 - 7 times to obtain the purified photosensitive polyimide resin. The specific process elements of the centrifugation process include the centrifugal speed and the filter bag specification;

[0033] Preferably, the process combination is a low centrifugal speed and a high filter bag mesh number.

[0034] The centrifugal dewatering process is equivalent to a filtration process. The filter bag mesh number essentially corresponds to the molecular weight of the recovered purified product. However, through experiments, it is found that the size of this mesh number needs to be moderate. If it is too large, it may affect the photosensitive performance of the compound obtained later. If it is too small, it will affect the outgas performance and purification efficiency.

[0035] Preferably, the centrifuge speed is 400 - 1000 rpm / min, and the filter bag specification is 400 - 800 mesh.

[0036] Preferably, the beating - centrifugation process is cycled 4 - 6 times.

[0037] In the beating process, the medium can usually be N - methylpyrrolidone, DMSO (dimethyl sulfoxide), or a mixed solution of N - methylpyrrolidone and water, a mixed solution of N - methylpyrrolidone and methanol, ethanol, etc., or a mixed solution of DMSO and water or methanol, ethanol, etc.

[0038] The inventor found that when the medium in the beating process is a mixed solution of N - methylpyrrolidone and water with a ratio of 1:7 - 1:9, the purification efficiency is the best.

[0039] Examples

[0040] Synthesis example: Synthesis of photosensitive polyimide prepolymer

[0041] Under nitrogen protection, 2,2 - bis(3 - amino - 4 - hydroxyphenyl)hexafluoropropane and 3,3,4,4 - dipropylether tetracarboxylic dianhydride are added together to a reaction kettle, maintained at 0°C, and kept at a constant temperature for 5 h. Then, the temperature is raised to 50°C, and the auxiliary agent N,N - dimethylformamide dimethyl acetal is added to the reaction system, and the reaction is continued at 50°C for 2 h to complete the synthesis reaction to prepare a photosensitive polyimide prepolymer solution. The photosensitive polyimide prepolymer solution is dried to obtain a photosensitive polyimide prepolymer, which is the ideal raw material for the purification process of the present invention, with a weight - average molecular weight Mw of 18000. The photosensitive polyimide resin completes the synthesis process, and the output is the photosensitive polyimide resin prepolymer, which is divided into several equal - proportion parts.

[0042] The photosensitive polyimide resin prepolymer in the synthesis example is purified and dried to obtain the photosensitive polyimide resin.

[0043] Mix the prepared resin (10 g), photosensitizer (2 g), crosslinking agent (1.5 g), 0.1% fluorosurfactant, 0.1% silane compound 1, and γ-butyrolactone (85 g) and dissolve them thoroughly to obtain a photosensitive resin composition.

[0044] Among them, the photosensitizer is Q is * represents the connection site of the group; the crosslinking agent is

[0045] Lithography performance test:

[0046] Apply the photosensitive resin composition onto a 4-inch square glass substrate by spin coating, pre-bake it at 120 °C for 180 s to remove most of the solvent, and form a film of about 10 μm. Expose it without a mask under a 365 nm ultraviolet exposure machine to decompose the photosensitive compound. Use a 2.38% TMAH (tetramethylammonium hydroxide) developer and develop it at 23 °C for 60 s to obtain a lithography pattern. The photosensitivity is the minimum exposure amount required to show a complete pattern within a 60 s development time.

[0047] Outgas test:

[0048] Sample preparation: Apply the prepared photosensitive resin composition onto a 4-inch square glass substrate by spin coating (250 rpm), pre-bake it at 120 °C for 180 s to remove most of the solvent, then place the coated glass substrate in a clean oven at 180 °C under nitrogen protection (oxygen concentration < 20 ppm) and cure it for 1 h. Scrape off the film, vacuum seal it, and store it for later use.

[0049] Test: Using the purge and trap method, under a helium gas flow, heat the collected cured film at 230 °C for 30 min, and adsorb the outgassing components using an adsorbent. At 250 °C, desorb the adsorbed components for 5 min, and analyze them using a gas chromatography-mass spectrometry (GC-Ms); at the same time, select n-hexadecane as the reference substance, draw a working standard curve, and calculate the outgassing amount converted according to n-hexadecane as the standard.

[0050] Comparative Example 1

[0051] Take 1 part of the photosensitive polyimide resin prepolymer, set the medium temperature at 30 °C, the stirring frequency at 50 Hz, add the prepolymer into the pulping kettle at a feeding speed of 4.5 L / min, select an 800-mesh filter bag after precipitation, set the centrifugal rotation speed at 1000 rpm / min, and perform the pulping and centrifugation process 6 times. Take samples for drying and detect the performance. The photosensitivity of the lithography performance is 720 mJ / cm 2 , and the outgas (small molecule volatiles) is 220 ppm;

[0052] Comparative Example 2

[0053] Set the medium temperature at 15°C, and keep other process conditions the same as those in Example 1. Take samples for drying and test the performance. The photosensitivity of the lithography performance is 780 mJ / cm 2 , and the outgas is 220 ppm;

[0054] Comparative Example 3

[0055] Set the medium temperature at 0°C, and keep other process conditions the same as those in Example 1. Take samples for drying and test the performance. The photosensitivity of the lithography performance is 800 mJ / cm 2 , and the outgas is 220 ppm;

[0056] Comparative Example 4

[0057] Set the stirring frequency at 40 Hz, and keep other process conditions the same as those in Example 1. Take samples for drying and test the performance. The photosensitivity of the lithography performance is 710 mJ / cm 2 , and the outgas is 235 ppm;

[0058] Comparative Example 5

[0059] Set the stirring frequency at 30 Hz, and keep other process conditions the same as those in Example 1. Take samples for drying and test the performance. The photosensitivity of the lithography performance is 680 mJ / cm 2 , and the outgas is 280 ppm;

[0060] Comparative Example 6

[0061] Set the feeding rate at 3.0 L / min, and keep other process conditions the same as those in Example 1. Take samples for drying and test the performance. The photosensitivity of the lithography performance is 775 mJ / cm 2 , and the outgas is 205 ppm;

[0062] Comparative Example 7

[0063] Set the feeding rate at 1.5 L / min, and keep other process conditions the same as those in Example 1. Take samples for drying and test the performance. The photosensitivity of the lithography performance is 846 mJ / cm 2 , and the outgas is 180 ppm;

[0064] Example 1

[0065] Set the medium temperature at 0°C, and keep other process conditions the same as those in Example 7. Take samples for drying and test the performance. The photosensitivity of the lithography performance is 950 mJ / cm 2 , and the outgas is 220 ppm;

[0066] Comparative Example 8

[0067] Set a 600-mesh filter bag, and the other process conditions are the same as those in Example 1. Sample and dry for performance testing. The photosensitivity of the lithography performance is 709 mJ / cm 2 , and the outgas is 210 ppm;

[0068] Comparative Example 9

[0069] Set a 400-mesh filter bag, and the other process conditions are the same as those in Example 1. Sample and dry for performance testing. The photosensitivity of the lithography performance is 698 mJ / cm 2 , and the outgas is 185 ppm;

[0070] Comparative Example 10

[0071] Set the centrifugal speed to 700 rpm / min, and the other process conditions are the same as those in Example 1. Sample and dry for performance testing. The photosensitivity of the lithography performance is 795 mJ / cm 2 , and the outgas is 280 ppm;

[0072] Comparative Example 11

[0073] Set the centrifugal speed to 400 rpm / min, and the other process conditions are the same as those in Example 1. Sample and dry for performance testing. The photosensitivity of the lithography performance is 890 mJ / cm 2 , and the outgas is 320 ppm;

[0074] Example 2

[0075] Set the centrifugal speed to 400 rpm / min, and the other process conditions are the same as those in Comparative Example 1. Sample and dry for performance testing. The photosensitivity of the lithography performance is 965 mJ / cm 2 , and the outgas is 300 ppm.

[0076] Comparative Example 12

[0077] Set the number of cycles of the beating and centrifugation processes to 5 times, and the other process conditions are the same as those in Example 1. Sample and dry for performance testing. The photosensitivity of the lithography performance is 856 mJ / cm 2 , and the outgas is 360 ppm;

[0078] Comparative Example 13

[0079] Set the number of cycles of the beating and centrifugation processes to 4 times, and the other process conditions are the same as those in Example 1. Sample and dry for performance testing. The photosensitivity of the lithography performance is 990 mJ / cm 2 , and the outgas is 510 ppm;

[0080] Comparative Example 14

[0081] Set the number of cycles for the beating and centrifugation processes to 4 times, and the other process conditions are the same as those in Comparative Example 2. Samples are taken for drying and their performance is tested. The photosensitivity of the lithography performance is 1009 mJ / cm 2 , and the outgas is 450 ppm.

[0082] The information of each actual test example is summarized in Table 1 below.

[0083] Table 1

[0084]

[0085]

[0086] The analysis based on the results is as follows:

[0087] (1) Referring to Comparative Examples 1-3, it can be seen that when the temperature of the medium during the first precipitation is too high, the lithography performance decreases;

[0088] (2) Referring to Comparative Examples 1, 4, and 5, it can be seen that when the stirring frequency during the first precipitation decreases, the lithography performance shows a decreasing trend and the outgas increases slightly;

[0089] (3) Referring to Comparative Examples 1, 6, and 7, it can be seen that when the feeding speed of the photosensitive polyimide prepolymer during the first precipitation decreases, the lithography performance is greatly improved and the outgas decreases;

[0090] (4) Comparing Example 1 with Comparative Example 7, it can be seen that under the combination of the three processes of low medium temperature, high stirring frequency, and low feeding speed, the lithography performance is greatly improved and the overall performance of the photosensitive polyimide resin tends to be the best;

[0091] (5) Referring to Comparative Examples 1, 8, and 9, it can be seen that when the mesh number of the filter bag decreases, both the lithography performance and the outgas decrease;

[0092] (6) Referring to Comparative Examples 1, 10, and 11, it can be seen that when the centrifugal speed decreases, both the lithography performance and the outgas are greatly improved;

[0093] (7) Comparing Examples 1 and 2 with Comparative Example 1, it can be seen that Example 2 has the best lithography performance and the outgas data is also within the qualified range;

[0094] (8) Referring to Comparative Examples 1, 12, and 13, it can be seen that when the number of beating and centrifugation cycles decreases, the lithography performance is greatly improved, but the outgas is also higher;

[0095] (9) Comparing Comparative Example 13 with Examples 2 and Comparative Example 14, it can be seen that Comparative Example 14 has excellent lithography performance, but the outgas data exceeds the range value;

[0096] (10) From the overall results, in the process combination scheme of Example 2, the overall performance of the photosensitive polyimide resin is better, and it can be determined as the optimal process.

[0097] In addition to the limitation of the three important process elements of the medium temperature, stirring frequency, and feeding speed in the pulping process section, it is also necessary to combine the selection of the centrifugal speed and filter bag specifications in the centrifugation stage, as well as the limitation of the number of cycles of the two processes of pulping and centrifugation. After the limitation combination of various key process elements, the optimal process route for the production of photosensitive polyimide resin can be quickly screened out.

[0098] According to the present invention, a purification method for a photosensitive polyimide material can be provided, which can enable the photosensitive polyimide resin material to achieve good stability between batches, and has good thermal stability, mechanical properties, electrical properties, chemical corrosion resistance and other properties, and can be widely used in the fields of electronic devices such as OLED flat panel displays and semiconductors.

[0099] The specific embodiments described above have further detailed the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is only specific embodiments of the present invention and is not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0100] The present invention uses the above embodiments to illustrate the detailed method of the present invention, but the present invention is not limited to the above detailed method, that is, it does not mean that the present invention must rely on the above detailed method to be implemented. Although the present invention has been described in conjunction with the embodiments, the present invention is not limited to the above embodiments. It should be understood that under the guidance of the inventive concept of the present invention, those skilled in the art can make various modifications and improvements. The appended claims summarize the scope of the present invention. The equivalent replacement of each raw material of the present invention product, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A purification method of a photosensitive polyimide resin, characterized in that, It includes a beating process and a separation and dewatering process. In the beating process, the prepolymer of photosensitive polyimide is added to the beating kettle at a feeding rate of 1 - 2.4 L / min, the medium temperature is set at 0 - 40 °C, and beating is carried out for 5 - 50 minutes. The condition is that the beating process and the separation and dewatering process are cycled 5 - 8 times to obtain the purified photosensitive polyimide resin.

2. The photosensitive polyimide resin according to claim 1, wherein, The molecular weight is 2000 - 100000. The preferred molecular weight is 5000 - 50000, and the more preferred molecular weight is 6000 - 30000.

3. The purification method of the photosensitive polyimide resin according to claim 1, wherein, In the beating process, the medium is a mixed solution of a solvent and water, and the boiling point range of the solvent is 50 °C - 250 °C under a standard atmospheric pressure of 0.1 MPa.

4. The purification method of the photosensitive polyimide resin according to claim 3, wherein The solvent can be selected from one or a mixture of several of N - methylpyrrolidone, dimethyl sulfoxide, N,N - dimethylacetamide, N,N - dimethylformamide, isopropanol, ethanol, and methanol.

5. The purification method of the photosensitive polyimide resin according to claim 4, wherein, In the beating process, the medium is a mixed solution of N - methylpyrrolidone and water with a ratio of 1:7 - 1:

9.

6. The purification method of the photosensitive polyimide resin according to claim 1, characterized in that, In the beating process, the stirring frequency is 35 - 100 Hz.

7. The purification method of the photosensitive polyimide resin according to claim 1, characterized in that the separation and dewatering includes centrifugal dewatering, and the centrifugal dewatering parameters are a centrifuge speed of 500 - 1000 rpm / min and a filter bag specification of 500 - 800 mesh; nitrogen pressure filtration dewatering, with a positive pressure of 0.08 MPa - 0.1 MPa; vacuum filtration dewatering, with a negative pressure of - 0.1 MPa - - 0.08 MPa; the separation and dewatering preferably uses centrifugal dewatering; after single - time separation and dewatering, the solid - liquid ratio is 1:3 - 1:2.

5.

8. The purification method of the photosensitive polyimide resin according to claim 1, characterized in that the prepolymer of the photosensitive polyimide is a prepolymer of polyamic acid or polyamic ester formed by copolymerization of diamine and dianhydride.

9. The purification method of the photosensitive polyimide resin according to claim 8, characterized in that the prepolymer of the polyimide is prepared by the following process: N - methylpyrrolidone, 2,2 - bis(3 - amino - 4 - hydroxyphenyl)hexafluoropropane, 3,3,4,4 - dipropylether tetracarboxylic dianhydride and an auxiliary agent are placed in a reaction kettle at 0 - 50 °C and kept at a constant temperature for 3 - 10 h. After the reaction is completed, the prepolymer solution of the photosensitive polyimide is obtained by filtration, and the prepolymer solution of the photosensitive polyimide is dried to obtain the prepolymer of the photosensitive polyimide.

10. A photosensitive polyimide resin purified by the purification method according to any one of claims 1 - 9.

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