CN108034062A - A kind of Black extinction-type polyimide film preparation method - Google Patents

Abstract

The present invention is a kind of Black extinction-type polyimide film preparation method, key step:Ith, polyamic acid resin solution is routinely prepared.IIth, black paste is prepared, black pigment amount is 2~20wt% of polyamic acid resin solution solid content M.IIIth, delustring agent dispersing liquid is prepared, delustring dosage is 2~20wt% of M.IVth, black polyamic acid resin solution is prepared, above-mentioned polyamic acid resin solution, black paste and delustring agent dispersing liquid blending and stirring, defoam spare.Vth, black polyamic acid solution routinely salivates, and gained polyamide acid film is first sent into high-temperature solvent pond, and applies ultrasonic wave to it and carry out hot solvent ultrasound reunion processing, post-tensioning, imidization and sizing, Black extinction-type polyimide film is made.The black pigment and delustering agent average grain diameter of the present invention is moderate, increases hot solvent ultrasound reunion processing after resin solution salivation, gained film light transmittance, glossiness and physico mechanical characteristic have clear improvement.

Description

A kind of black extinction type polyimide film preparation method

technical field

The invention relates to a polyimide film manufacturing technology, in particular to a method for preparing a black matte polyimide film.

Background technique

Flexible printed circuit board (FPC) is widely used in 3C products, optical lens modules, liquid crystal display (LCD) modules and solar cells and other products, and polyimide film (Polyimide Film, referred to as PI film) is often used as its substrate Or cover film material, due to the high surface flatness of the traditional PI film in the application process, the surface of the film reflects most of the incident light and produces high gloss. The high-gloss film surface has glare or astigmatism caused by light reflection, which causes visual discomfort and easily fatigues the eyes when watching for a long time. Especially for high-gloss PI film polyimide films with black, white, blue, red and other colors, the reflected light on the surface has a more significant impact on vision.

On the other hand, when the PI film with high surface gloss and high transparency is applied to FPC, the circuit design distribution of FPC is easy to interpret and is plagiarized by the industry.

Therefore, the market demands PI films with low gloss, low light transmittance and high dielectric strength. The high dielectric strength and low light transmittance of the low-gloss black PI film can protect the internal circuit design, and at the same time make the appearance of the component more textured and beautiful.

At present, the production process of polyimide film is to use the polyamic acid resin solution synthesized by polycondensation reaction as raw material, and salivate on the salivating machine to obtain a self-supporting polyamic acid thick film, and then heat stretching, imidization, The polyimide film is obtained by setting treatment. In order to obtain a polyimide film with low gloss, low light transmittance and high dielectric strength, coloring additives (such as colorants, dyes, etc.) and matting agents must be added during the preparation of the polyimide film. The general process is to use colored additives to reduce the light transmittance of the polyimide film, or add a matting agent to form a concave-convex microstructure on the surface of the polyimide film to reduce the gloss of the polyimide film.

In the prior art, matting agents with micron-sized particles are generally used. Because the filter element of the filter system of the existing extrusion die has a small pore size, the matting agent often causes the filter system to be blocked during the extrusion process, and it is impossible to achieve a long-term continuous process. chemical film. If the pore size of the filter element of the filtration system is increased, it is easy to cause foreign matter such as impurities and gels in the resin solution to embed into the film, resulting in a decrease in the surface quality of the film.

During the manufacturing process of black polyimide film, when the particle size of inorganic particles (matting agent) or carbon powder material (coloring additive) is too large or too small, or the amount added is too high or too low, it will affect the polyimide film. The physical properties of imide films are adversely affected. If the particle size of inorganic particles or carbon powder materials is large, the surface of the film produced is too rough, which is not suitable for electronic products; The problem of uneven dispersion of additives in the medium, and the operation of the production process is not easy to control. What affects the dispersion of additives in the polyimide film is not only the particle size of inorganic particles or carbon powder materials, but also the content of inorganic particles or carbon powder materials. If the content of inorganic particles or carbon powder materials in the film is too small, the gloss and light transmittance of the film cannot be reduced to meet the requirements. When the content is large, the problem of uneven dispersion of additives will also occur; adding a large amount of matting agent will also lead to deterioration of the performance of the polyimide film, easy to be brittle, and a large amount of additives are prone to sedimentation and agglomeration in the polyamic acid resin. It also increases the production cost of the film.

Matting agent materials can be divided into inorganic compounds and organic compounds. Among them, inorganic compounds include silicon oxide, aluminum oxide, calcium carbonate, barium sulfate, titanium dioxide, etc. Inorganic particles have a high packing density. Adding a large amount of inorganic particles may lead to agglomeration and uneven dispersion in the polyimide matrix , thereby reducing the consistency of the electrical insulation of the film, which is not conducive to subsequent applications. The organic compounds used in matting agents include polycarbonate (PC), polystyrene (PS), polymethyl methacrylate (PMMA), polyethylene (PE), polypropylene (PP), polyterephthalic acid Ethylene glycol (PET), epoxy resin, etc. Because in the preparation process of the polyimide film, the chemical conversion temperature must exceed 250°C, but none of the above-mentioned organic compounds can withstand the temperature of 250°C or higher. When this type of organic compound is added to the polyimide film as a matting agent, it will cause cracks or holes in the film, or defects such as plaques with inconsistent colors due to uneven melting.

At present, the main production technology of matte black PI film is divided into two categories: one is to add black pigment and matting agent filler to PI resin, and then undergo chemical imidization or thermal imidization to synthesize a film with low light transmittance and Low-gloss PI film, this method is easy to operate and the effect is obvious, but due to the addition of a large amount of fillers, the mechanical properties of the PI film are greatly reduced; the other is to coat one or both sides of the PI base film Coated with a PI film containing black pigment and matting effect. Though this kind of method can make polyimide film present desired black effect preferably, and can guarantee the certain mechanical performance of polyimide film, but the black resin of additional coating usually increases manufacturing process and cost, and Detrimental effects on the properties of polyimide film. In addition, polyimide films are prone to performance degradation when exposed to thermal stress due to the poor heat resistance of the resin coating layer. There are many patent applications related to the manufacture of low-gloss black polyimide films, but they are difficult to implement due to defects such as complicated manufacturing process, high requirements for production control precision and high manufacturing cost.

For example, the Chinese invention patent CN104742461A "Low-gloss double-layer polyimide film and its manufacturing method" applied in 2015 inserts a black pigment mixed between the upper and lower polyimide films and forms in the thickness direction of the film. The polyimide film with recesses and holes can obtain a double-layer polyimide film with high light-shielding properties and low gloss. The Chinese invention patent CN 104830058A "Low dielectric constant and low gloss polyimide film and its preparation method" applied in 2015, the main structure of the film is polyimide, 0.5wt% to 5wt% carbon black, and The 15wt% to 40wt% fluorine-containing polymer is a single-layer film or a multi-layer film. The Chinese invention patent "Matting agent composed of polyimide powder, polyimide film containing the matting agent and its preparation method" applied in 2012 discloses that the organic matting Distributed in polyimide film to make polyimide film with good film properties and low gloss. The Chinese invention patent CN103561953A "polyimide film" applied in 2012 has a polyimide layer (B) containing inorganic or organic fillers on one or both sides of the polyimide layer (A) containing black organic pigments ), the film is excellent in electrical insulation and electrical reliability.

Contents of the invention

The purpose of this invention is to design a kind of black matting type polyimide film preparation method, adopt the inorganic filler matting agent that average particle size is smaller than the matting agent that this type of film generally uses to prepare polyamic acid resin solution, extrude The self-supporting polyamic acid film formed by salivation is first subjected to hot solvent ultrasonic agglomeration treatment, and then biaxial stretching, high temperature imidization and setting treatment. The glossiness and light transmittance of the polyimide film produced by this method are significantly reduced, the surface smoothness of the film roll is increased, and the appearance is greatly improved.

A kind of black extinction type polyimide film preparation method provided by the invention comprises following main steps:

Ⅰ. Preparation of polyamic acid resin solution

Prepare the polyamic acid resin solution according to the conventional method. In an inert atmosphere, under the condition of controlling the temperature of the synthesis system at 12°C to 75°C, add aromatic diamine to the solvent for stirring and dissolving. After the aromatic diamine is completely dissolved, divide it into 3 Add aromatic dianhydride with a molar ratio of (0.9~1.1):1 to aromatic diamine at a uniform speed for ~8 times, and stir at 120r/min~1200r/min, and synthesize polyamic acid resin solution through polycondensation reaction for 3~24h .

Considering the cost, the inert atmosphere is generally realized with nitrogen.

The solvent is an aprotic polar solvent with a low molecular weight carboxylamide, specifically N,N'-dimethylacetamide (DMAC), N,N'-dimethylformamide (DMF), N-methylpyrrolidone Any one of (NMP), dimethylsulfoxide (DMSO), tetramethylsulfone, N,N'-dimethyl-N,N'-propenyl urea (DMPU), N,N dialkylcarboxamide species or any combination of them.

The amount of aromatic diamine, aromatic diacid anhydride and solvent is controlled so that the ratio of solid content M in the polyamic acid resin solution formed in this step is 10wt%-50wt%.

The aromatic diamine is 3,4'-diaminodiphenyl ether, 1,3-bis-(4-aminophenoxy)benzene, 4,4'-diaminodiphenyl ether (4,4'- ODA), 1,3-diaminobenzene, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-diaminobenzidine and p-phenylenediamine (p-PDA) or any combination of them.

The aromatic dianhydrides are pyromellitic diacid (PMDA), 3,3',4,4'-biphenyl tetracarboxylic dianhydride (BPDA), 2,2',3,3'-biphenyl Tetracarboxylic dianhydride (BPDA), diphenyl ether tetracarboxylic dianhydride (ODPA), benzophenone tetracarboxylic dianhydride (BTDA), 2,2-bis(3,4-dicarboxylic acid phenyl)hexafluoropropane Dianhydride (6FDA), 4,4'-oxydiphthalic anhydride (ODPA), 3,4,3',4'-diphenylsulfide tetracarboxylic dianhydride (3,4,3',4' -TDPA), 2,3,2',3'-diphenylsulfide tetracarboxylic dianhydride (2,3,2',3'-TDPA) and 2,3,3',4'-diphenylsulfide Any one or any combination of tetracarboxylic dianhydride (2,3,3',4'-TDPA).

Ⅱ. Black slurry preparation

Take the black pigment and add it to the solvent, mix and stir to obtain a black slurry; the amount of the black pigment added is 2wt%～20wt% of the solid content M in the polyamic acid resin solution described in step 1, and the average particle diameter of the black pigment is 0.01～20wt%. 0.8 μm.

The solvent is an aprotic polar solvent with a low molecular weight carboxylamide, specifically N,N'-dimethylacetamide (DMAC), N,N'-dimethylformamide (DMF), N-methylpyrrolidone Any one of (NMP), dimethylsulfoxide (DMSO), tetramethylsulfone, N,N'-dimethyl-N,N'-propenyl urea (DMPU), N,N dialkylcarboxamide species or any combination of them.

The amount of solvent used in the black slurry is controlled so that the content ratio of the black pigment in the black slurry is 10wt%-30wt%.

The amount of the added black pigment is preferably 6wt%-10wt% of M.

In a preferred solution, the average particle diameter of the added black pigment is 0.015 μm to 0.4 μm, preferably 0.02 μm to 0.1 μm. If the particle size of the black pigment is small, it is easy to aggregate, causing uneven dispersion in the film, and it is difficult to control the process operation. If the particle size of the black pigment is large, the surface of the film will be too rough, which is not suitable for electronic products; Amine film properties.

The mixing and stirring after the black pigment is added to the solvent is first mixing, shearing and stirring, then shearing and emulsifying treatment by a high-speed dispersing emulsifier, and then high-pressure homogenization treatment by a high-pressure homogenizer to obtain a black slurry.

Ⅲ. Preparation of matting agent dispersion

Add the matting agent into the solvent, mix and stir evenly to obtain the matting agent dispersion, the added matting dose is 2wt% to 20wt% of the solid content M in the polyamic acid resin solution described in step I, and the average particle size of the matting agent is 0.01～0.8μm.

The solvent is an aprotic polar solvent with a low molecular weight carboxylamide, specifically N,N'-dimethylacetamide (DMAC), N,N'-dimethylformamide (DMF), N-methylpyrrolidone Any one of (NMP), dimethylsulfoxide (DMSO), tetramethylsulfone, N,N'-dimethyl-N,N'-propenyl urea (DMPU), N,N dialkylcarboxamide species or any combination of them.

The matting agent is any one or a combination of any of silicon dioxide, polyimide, aluminum oxide and titanium dioxide.

The amount of solvent used in the matting agent dispersion is controlled so that the content ratio of the matting agent in the matting agent dispersion is 10 wt% to 30 wt%.

The preferred solution is that the amount of matting agent added is 8wt%-12wt% of M.

In a preferred solution, the average particle size of the added matting agent is 0.05 μm to 0.6 μm, preferably the average particle size of the added matting agent is 0.08 μm to 0.3 μm.

If the average particle diameter of the matting agent is too small relative to the thickness of the polyimide film to be prepared, the effect of suppressing glossiness will be reduced; if it is too large, it cannot be sufficiently fixed on the polyimide film. If the added amount of the filler is too small, the effect of suppressing the glossiness will also decrease; if it is too large, the physical properties of the polyimide film will be damaged.

The mixing and stirring after the matting agent is added to the solvent is firstly mixed and sheared, then sheared and emulsified by a high-speed dispersing emulsifier, then ground by a grinder, and further ultrasonically dispersed to obtain a matting agent dispersion.

The same solvents are used in the preparation of the polyamic acid resin solution in the step I, the preparation of the black slurry in the step II and the preparation of the matting agent dispersion in the step III.

Ⅳ. Preparation of black polyamic acid resin solution

Take the polyamic acid resin solution obtained in step I, the black slurry obtained in step II and the matting agent dispersion obtained in step III, blend and stir to prepare a black polyamic acid resin solution, and defoam it for later use;

Ⅴ. Preparation of black matte polyimide film

The black polyamic acid solution prepared in step IV is coated on the endless steel belt through an extrusion molding die, with a thickness of 20-520 μm, and then dried at 100-250°C to remove 60wt%-35wt% of the solvent to obtain a self-supporting polyamic acid solution. The obtained polyamic acid film is peeled off from the endless steel belt, sent into a solvent pool with a temperature of 50°C to 180°C, and applied with an ultrasonic frequency of 20KHZ to 150KHZ and an ultrasonic power of 0.5KW to 3.6KW. Ultrasonic, hot solvent ultrasonic agglomeration treatment time in the solvent pool is 10s ~ 180s.

The hot solvent ultrasonic agglomeration treatment causes the matting agent and black pigment contained on the upper and lower surfaces of the polyamic acid film to migrate, wriggle and gather uniformly (especially the matting agent inorganic fillers are obviously and uniformly aggregated), and the fillers are formed by self-assembly behavior (micron-scale) rough and irregularly shaped modified surface, reducing film gloss. If the temperature of the solvent is too low during processing, the extinction effect will not be obvious; if the temperature is too high, the film will easily dissolve, resulting in film breakage, affecting the continuous production of the film; if the treatment time is too short, the extinction effect will not be obvious, and if the treatment time is too long, it will easily Causes the film to dissolve, causing the problem of abnormal continuous production of the film.

The solvent in the high-temperature solvent pool of the hot solvent ultrasonic agglomeration treatment is an aprotic polar solvent low molecular weight carboxamide, specifically N,N'-dimethylacetamide (DMAC), N,N'-dimethylformamide N, N, N, N, Any one or any combination of N-dialkylcarboxamides.

The temperature of the hot solvent ultrasonic agglomeration treatment in the preferred solution is 60°C-150°C, and the time is 20s-120s.

In the preferred solution, the temperature of the hot solvent ultrasonic agglomeration treatment is 80°C-120°C, and the time is 30s-60s.

Further, the applied ultrasonic frequency is 60KHZ-100KHZ, and the power is 1.8KW-2.8KW.

The polyamic acid film treated by the hot solvent ultrasonic agglomeration is transported to the vertical and horizontal bidirectional stretching machine for 0.8-2.2 times stretching, 180°C-500°C high-temperature imidization treatment, and finally 180°C-360°C after setting, winding , to prepare a black matte polyimide film with a thickness of 2.5-50 μm.

Compared with the prior art, the advantages of a method for preparing a black matting polyimide film of the present invention are: 1. The median particle size of conventional matting agents is in the order of microns, while the particle size of matting agents of the present invention is only 0.01 to 0.8 μm 1. The self-supporting polyamic acid film formed by extrusion and salivation is first subjected to hot solvent ultrasonic agglomeration treatment, and the polyamic acid film is ultrasonically treated in a hot solvent to agglomerate the matting agent and black pigment and reduce the surface gloss of the film; 2. The prepared black matte polyimide film has a visible light transmittance of less than 0.1%, a 60° gloss value of <25, an elongation of >60%, a tensile strength of > 230MPa, and a modulus of elasticity > 3.5GPa, and maintains polyimide The insulation and mechanical properties of the imide film itself; 3. The prepared black matte polyimide film has light-shielding and matting effects, and the treatment of ultrasonic agglomeration in hot solvent also enhances the tear resistance of the film; 4 1. The solvent pool of the hot solvent ultrasonic agglomeration treatment added is located after the existing salivating machine and before the biaxial stretching machine. It is easy to debug, and can ensure continuous production, simple process and convenient operation; 5. The black prepared by this method Matte polyimide film is suitable for base film or cover film of flexible printed circuit board, base film for electronic label, etc.

Detailed ways

Example 1

Ⅰ. Preparation of polyamic acid resin solution

In a nitrogen atmosphere, the temperature of the synthesis system is controlled to be 12°C, and 2.39 kg of aromatic diamine 4,4'-diaminodiphenyl ether (4,4 '-ODA) was stirred and dissolved. After 4,4'-ODA was completely dissolved, 2.61kg of aromatic dianhydride pyromellitic acid diacid (PMDA) was added at a constant speed in 8 times at a molar ratio of 1:1 to the aromatic diamine. , and stirred at 1200r/min, synthesized by polycondensation reaction for 12h to obtain a polyamic acid resin solution with a solid content of M=5kg, that is, a solid content ratio of 10wt%;

Ⅱ. Black slurry preparation

20wt% of the solid content M in the polyamic acid resin solution gained by step 1 gets carbon black 1kg and adds solvent N, N'-dimethylacetamide (DMAC) 2.33kg and mixes and stirs to obtain carbon black content 30% Black slurry; the average particle size of carbon black in this example is 0.01 μm.

The black pigment in this step can also be any one or more of titanium black, bone charcoal (bone black), cyanine black (cyanine black), acetylene black, lamp black, graphite, iron black, aniline black and cyanine black The combination.

In this example, the mixing and stirring after adding the black pigment carbon black to the N,N'-dimethylacetamide (DMAC) solvent is first mixed and sheared at 120r/min for 30 minutes, and then passed through a 3600r/min high-speed dispersing emulsifier Shearing and emulsifying treatment for 240 minutes, followed by 180MPa high-pressure homogenization treatment for 30 minutes in a high-pressure homogenizer to obtain a black slurry.

Ⅲ. Preparation of matting agent dispersion

Add 0.1kg of 2wt% delustering agent silicon dioxide of solid content M in the polyamic acid resin solution of step I gained to solvent N, after mixing and stirring in N'-dimethylacetamide (DMAC) 0.5kg, obtain two For a matting agent dispersion with a silicon oxide content ratio of 20%, the average particle size of silicon dioxide in this example is 0.8 μm.

The matting agent in this step can also be any one or a combination of any of polyimide, aluminum oxide and titanium dioxide.

In this example, the solvent N,N'-dimethylacetamide (DMAC) is mixed and stirred after adding the matting agent silica to the condition of 1200r/min for 30 minutes, followed by high-speed dispersion and emulsification at 1200r/min Machine shearing emulsification treatment for 30 minutes, followed by milling treatment for 30 minutes, and further ultrasonic dispersion treatment for 240 minutes to obtain a matting agent dispersion.

Ⅳ. Preparation of black polyamic acid resin solution

The polyamic acid resin solution obtained in step I, the black slurry obtained in step II, and the matting agent dispersion obtained in step III were blended and stirred to prepare a black polyamic acid resin solution, which was defoamed for later use.

Ⅴ. Preparation of black matte polyimide film

The black polyamic acid solution prepared in step IV is coated on an endless steel belt through an extrusion molding die, with a thickness of 20 μm, and then dried at 100°C to remove 35wt% of the solvent to obtain a self-supporting polyamic acid film. Example The obtained polyamic acid film is peeled off from the endless steel belt, and sent into the N,N'-dimethylacetamide (DMAC) solvent pool at a temperature of 50°C, and an ultrasonic frequency of 20KHZ and an ultrasonic power of 0.5KW is applied to it. Ultrasonic, the hot solvent ultrasonic agglomeration treatment time in the solvent pool is 180s.

The polyamic acid film treated by the above hot solvent ultrasonic agglomeration is transported to the vertical and horizontal bidirectional stretching machine for 2.2 times stretching, 500°C high temperature imidization treatment, and then 360°C shaping, and finally winding to obtain a thickness of 2.5 μm. Black matte polyimide film.

Example 2

Ⅰ. Preparation of polyamic acid resin solution

In a nitrogen atmosphere, control the temperature of the synthesis system at 22°C, add 6.38kg of aromatic diamine 2,2'-bis(trifluoromethyl)benzidine to 37.5kg of N,N'-dialkylcarboxamide solvent and stir Dissolve, after it is completely dissolved, add 5.99 kg of aromatic dianhydride 3,3',4,4'-biphenyl tetracarboxylic acid dianhydride (BPDA ), and stirred at 1000r/min, synthesized by polycondensation reaction for 8h to obtain a polyamic acid resin solution with a solid content of M=12.4kg, that is, a solid content ratio of 25wt%;

Ⅱ. Black slurry preparation

According to the 16wt% of the solid content M in the polyamic acid resin solution that step 1 gains gets iron black 2kg to add solvent N, N'-dimethyl sulfoxide (DMSO) 18kg mixes and stirs and obtains the black slurry of iron black content 10%. Material; the average particle size of iron black in this example is 0.8 μm.

The mixing and stirring after adding the black pigment in the solvent of this example is similar to Example 1.

Ⅲ. Preparation of matting agent dispersion

Add 2.5kg of 20wt% delustering agent silicon dioxide with a solid content M in the polyamic acid resin solution obtained in step 1 into 5.8kg of solvent N-methylpyrrolidone (NMP) and mix and stir to obtain a silicon dioxide content ratio of 30. % matting agent dispersion, the average particle size of silicon dioxide in this example is 0.01 μm.

The mixing and stirring after adding the matting agent in the solvent of this example is similar to Example 1.

Ⅳ. Preparation of black polyamic acid resin solution

The preparation of the black polyamic acid resin solution in this step is the same as in Example 1.

Ⅴ. Preparation of black matte polyimide film

The black polyamic acid solution prepared in step IV is coated on an endless steel belt through an extrusion molding die, with a thickness of 520 μm, and then dried at 250°C to remove 60wt% of the solvent to obtain a self-supporting polyamic acid film. Example The obtained polyamic acid film was peeled off from the endless steel belt, and sent into the N,N'-dimethylacetamide (DMAC) solvent pool with a temperature of 180°C, and an ultrasonic frequency of 150KHZ and an ultrasonic power of 3.6KW was applied to it. Ultrasonic, the hot solvent ultrasonic agglomeration treatment time in the solvent pool is 10s.

The polyamic acid film treated by the above hot solvent ultrasonic agglomeration is transported to the vertical and horizontal bidirectional stretching machine for 0.8 times stretching, 180°C high-temperature imidization treatment, and then 180°C shaping, and finally winding to obtain a black film with a thickness of 50 μm. Matte polyimide film.

Example 3

Ⅰ. Preparation of polyamic acid resin solution

In a nitrogen atmosphere, the temperature of the synthesis system is controlled at 50°C, and 7.92kg of aromatic diamine 3,4'-diaminodiphenyl ether (3,4'-ODA) is added to 25kg of N-methylpyrrolidone (NMP) solvent to carry out Stir to dissolve, and after it is completely dissolved, add 17.23 kg of aromatic dianhydride 2,2-bis(3,4-dicarboxylic acid phenyl)hexafluoro at a uniform speed of 5 times at a molar ratio of 1.02:1 to the aromatic diamine Propane dianhydride (6FDA), stirred at 1000r/min, synthesized by polycondensation for 8 hours to obtain a solid content M = 25.15kg, that is, a polyamic acid resin solution with a solid content ratio of 50wt%;

Ⅱ. Black slurry preparation

4wt% of the solid content M in the polyamic acid resin solution obtained by step 1 gets acetylene black 1kg and adds in solvent N-methylpyrrolidone (NMP) 5.6kg and mixes and stirs to obtain the black slurry of acetylene black content 15%; For example, the average particle size of acetylene black is 0.02 μm.

The mixing and stirring after adding the black pigment in the solvent of this example is similar to Example 1.

Ⅲ. Preparation of matting agent dispersion

Add 4.04kg of 16wt% delustering agent aluminum oxide with a solid content M in the polyamic acid resin solution obtained in step I to add solvent N, N'-dimethylsulfoxide (DMSO) 16kg, mix and stir to obtain the aluminum oxide content ratio 20% matting agent dispersion, the average particle size of alumina in this example is 0.3 μm.

The mixing and stirring after adding the matting agent in the solvent of this example is similar to Example 1.

Ⅳ. Preparation of black polyamic acid resin solution

The preparation of the black polyamic acid resin solution in this step is the same as in Example 1.

Ⅴ. Preparation of black matte polyimide film

The black polyamic acid solution prepared in step IV is coated on an endless steel belt through an extrusion molding die, with a thickness of 250 μm, and then dried at 180°C to remove 50wt% of the solvent to obtain a self-supporting polyamic acid film. Example The obtained polyamic acid film is peeled off from the endless steel belt, and sent to the N,N'-dimethylacetamide (DMAC) solvent pool with a temperature of 150°C, and an ultrasonic frequency of 100KHZ and an ultrasonic power of 2.8KW is applied to it. Ultrasonic, the hot solvent ultrasonic agglomeration treatment time in the solvent pool is 20s.

The polyamic acid film treated by the above-mentioned hot solvent ultrasonic agglomeration is transported to the vertical and horizontal bidirectional stretching machine for 1.2 times stretching, 380°C high temperature imidization treatment, and then 250°C shaping, and finally winding to obtain a black film with a thickness of 25 μm. Matte polyimide film.

Example 4

Ⅰ. Preparation of polyamic acid resin solution

In an argon atmosphere, the temperature of the synthesis system is controlled to be 60°C, and 2.22kg of the aromatic diamine p-phenylenediamine ( p-PDA) was stirred and dissolved, and after p-PDA was completely dissolved, it was 5.48kg aromatic dianhydride biphenyltetracarboxylic dianhydride (BPDA) that was 1.1:1 with the aromatic diamine mol ratio and added at a uniform speed in 5 times, and Stir at 800r/min, synthesize polyamic acid resin solution with solid content M=7.70kg, that is, a solid content ratio of 15wt%, through polycondensation reaction for 3h;

Ⅱ. Black slurry preparation

According to the 6wt% of the solid content M in the polyamic acid resin solution gained in step 1, get titanium black 0.47kg and add solvent N, mix and stir in 4.23kg of N'-dialkyl carboxamides to obtain the black slurry of titanium black content 10%. Material; the average particle size of titanium black in this example is 0.1 μm.

The mixing and stirring after adding the black pigment in the solvent of this example is similar to Example 1.

Ⅲ. Preparation of matting agent dispersion

Add 0.39kg of the 5wt% delustering agent titanium dioxide of the solid content M in the polyamic acid resin solution obtained by step 1 into the solvent N, N'-dialkylcarboxamide 2.86kg and mix and stir to obtain a titanium dioxide content ratio of 12%. Matting agent dispersion, the average particle size of titanium dioxide in this example is 0.08 μm.

The mixing and stirring after adding the matting agent in the solvent of this example is similar to Example 1.

Ⅳ. Preparation of black polyamic acid resin solution

The preparation of the black polyamic acid resin solution in this step is the same as in Example 1.

Ⅴ. Preparation of black matte polyimide film

The black polyamic acid solution prepared in step IV is coated on an endless steel belt through an extrusion molding die, with a thickness of 360 μm, and then dried at 150°C to remove 40wt% of the solvent to obtain a self-supporting polyamic acid film. Example The obtained polyamic acid film is peeled off from the endless steel belt, and sent into the N,N'-dimethylformamide (DMF) solvent pool with a temperature of 120°C, and an ultrasonic frequency of 60KHZ and an ultrasonic power of 1.8KW is applied to it. Ultrasonic, the hot solvent ultrasonic agglomeration treatment time in the solvent pool is 30s.

The polyamic acid film treated by the above hot solvent ultrasonic agglomeration is transported to the vertical and horizontal bidirectional stretching machine for 1.4 times stretching, 450°C high-temperature imidization treatment, and then 300°C shaping, and finally winding to obtain a black film with a thickness of 36 μm. Matte polyimide film.

Example 5

Ⅰ. Preparation of polyamic acid resin solution

In an argon atmosphere, control the temperature of the synthesis system at 15°C, add 2.49kg of the aromatic diamine p-phenylenediamine (p-PDA) to 40kg of N,N'-dimethylsulfoxide (DMSO) solvent and stir to dissolve it. After it was completely dissolved, 7.51 kg of 3,4,3',4'-diphenylsulfide tetracarboxylic dianhydride (3,4,3', 4'-TDPA), and stirred at 800r/min, synthesized by polycondensation reaction for 8h to obtain a solid content M=10kg, that is, a polyamic acid resin solution with a solid content ratio of 20wt%;

Ⅱ. Black slurry preparation

According to 2wt% of the solid content M in the polyamic acid resin solution obtained in step 1, take 0.2 kg of nigrosine and add it into solvent N, N'-dimethyl sulfoxide (DMSO) 0.64 kg, mix and stir to obtain 30% nigrosine content black slurry; the average particle size of nigrosine in this example is 0.4 μm.

The mixing and stirring after adding the black pigment in the solvent of this example is similar to Example 1.

Ⅲ. Preparation of matting agent dispersion

Add 0.8kg of the 8wt% delustering agent titanium dioxide of the solid content M in the polyamic acid resin solution obtained by step 1 into the solvent N, N'-dimethyl sulfoxide (DMSO) 1.86kg, mix and stir to obtain a titanium dioxide content ratio of 30 % matting agent dispersion, the average particle size of titanium dioxide in this example is 0.05 μm.

The mixing and stirring after adding the matting agent in the solvent of this example is similar to Example 1.

Ⅳ. Preparation of black polyamic acid resin solution

The preparation of the black polyamic acid resin solution in this step is the same as in Example 1.

Ⅴ. Preparation of black matte polyimide film

The black polyamic acid solution prepared in step IV is coated on an endless steel belt through an extrusion molding die, with a thickness of 400 μm, and then dried at 200°C to remove 30wt% of the solvent to obtain a self-supporting polyamic acid film. Example The obtained polyamic acid film is peeled off from the endless steel belt, and sent into the N,N'-dimethyl sulfoxide (DMSO) solvent pool at a temperature of 80°C, and an ultrasonic wave with an ultrasonic frequency of 90KHZ and an ultrasonic power of 2.2KW is applied to it. , the hot solvent ultrasonic agglomeration treatment time in the solvent pool is 60s.

The polyamic acid film treated by the above-mentioned hot solvent ultrasonic agglomeration is transported to the vertical and horizontal bidirectional stretching machine for 1-fold stretching, 250°C high-temperature imidization treatment, and then 220°C for shaping, and finally winding to obtain a black film with a thickness of 40 μm. Matte polyimide film.

Example 6

Ⅰ. Preparation of polyamic acid resin solution

In an argon atmosphere, the temperature of the synthesis system is controlled at 72°C, and 4.79 kg of aromatic diamine 4,4'-diaminodiphenyl ether (4, 4'-ODA) was stirred and dissolved, and after 4,4'-ODA was completely dissolved, 5.21kg of aromatic diacid anhydride pyromellitic diacid (PMDA ), and stirred at 800r/min, synthesized by polycondensation reaction for 12h to obtain a polyamic acid resin solution with a solid content M=10kg, that is, a solid content ratio of 20wt%;

Ⅱ. Black slurry preparation

2wt% of the solid content M in the polyamic acid resin solution gained by step 1 gets graphite 1kg and adds solvent N, mixes and stirs in 2.33kg of N'-dimethylacetamide (DMAC) and obtains the black slurry of graphite content 30%. Material; the average particle size of graphite in this example is 0.015 μm.

The mixing and stirring after adding the black pigment in the solvent of this example is similar to Example 1.

Ⅲ. Preparation of matting agent dispersion

Add 1.2kg of the 12wt% delustering agent polyimide of solid content M in the polyamic acid resin solution gained in step I to the solvent N, mix and stir in 2.8kg of N'-dimethylacetamide (DMAC) to obtain For a matting agent dispersion with a polyimide content ratio of 30%, the average particle size of the polyimide in this example is 0.6 μm.

The mixing and stirring after adding the matting agent in the solvent of this example is similar to Example 1.

Ⅳ. Preparation of black polyamic acid resin solution

The preparation of the black polyamic acid resin solution in this step is the same as in Example 1.

Ⅴ. Preparation of black matte polyimide film

The black polyamic acid solution prepared in step IV is coated on an endless steel belt through an extrusion molding die, with a thickness of 100 μm, and then dried at 220°C to remove 55wt% of the solvent to obtain a self-supporting polyamic acid film. Example The obtained polyamic acid film is peeled off from the endless steel belt, and sent into the N,N'-dimethylacetamide (DMAC) solvent pool with a temperature of 60°C, and an ultrasonic frequency of 120KHZ and an ultrasonic power of 3.2KW is applied to it. Ultrasonic, the hot solvent ultrasonic agglomeration treatment time in the solvent pool is 120s.

The polyamic acid film treated by the above hot solvent ultrasonic agglomeration is transported to the vertical and horizontal bidirectional stretching machine for 2 times stretching, 300°C high-temperature imidization treatment, and then 260°C for shaping, and finally winding to obtain a black film with a thickness of 10 μm. Matte polyimide film.

Comparative example ①

Steps Ⅰ to Ⅳ are all the same as in Example 1,

Step Ⅴ When preparing the polyimide film, there is no ultrasonic agglomeration treatment with a hot solvent, and only coating, drying and curing, stretching, imidization, and setting treatments are carried out according to conventional film-making processes to obtain a black polyimide film.

Comparative example②

Step Ⅰ, Ⅱ and step Ⅳ, Ⅴ are all identical with embodiment 1,

During the preparation of the matting agent dispersion in step III, the average particle size of the matting agent silicon dioxide is 2 μm, greater than 1 μm. Still according to the 2wt% of the solid content M in the polyamic acid resin solution gained in step I, get 0.1kg silicon dioxide and add solvent N, after mixing and stirring in N'-dimethylacetamide (DMAC) 0.5kg, obtain the silicon dioxide A matting agent dispersion with a silicon content ratio of 20%.

Comparative example③

Step Ⅰ, Ⅱ and step Ⅳ, Ⅴ are all identical with embodiment 1,

During the preparation of the matting agent dispersion in step III, the average particle size of the matting agent silicon dioxide is 0.008 μm, less than 0.01 μm.

Other preparation methods are the same as step III of Example 1.

Comparative example ④

Step Ⅰ, Ⅲ and step Ⅳ, Ⅴ are all identical with embodiment 1,

During the preparation of the black slurry in step II, the average particle size of the carbon black is 1.8 μm, which is greater than the upper limit of the average particle size of the black pigment required by the present invention, which is 0.8 μm.

Other preparation methods are the same as step II of Example 1.

Comparative example ⑤

Step Ⅰ, Ⅲ and step Ⅳ, Ⅴ are all identical with embodiment 1,

During the preparation of the black slurry in step II, the average particle size of the carbon black is 0.008 μm, which is smaller than the lower limit of the average particle size of the black pigment required by the present invention, which is 0.01 μm.

Other preparation methods are the same as step II of Example 1.

Comparative example ⑥

Steps Ⅰ to Ⅳ are all the same as in Example 1,

During the preparation of step Ⅴ black matting polyimide film, the obtained polyamic acid film is peeled off from the endless steel belt, and sent to a N,N'-dimethylacetamide (DMAC) solvent pool at a temperature of 30°C, and Ultrasonic waves with an ultrasonic frequency of 180KHZ and an ultrasonic power of 0.2KW were applied to it, and the hot solvent ultrasonic agglomeration treatment time in the solvent pool was 300s. Other processing methods of this step are identical with embodiment 1 step V.

Comparative example⑦

Steps Ⅰ to Ⅳ are all the same as in Example 1,

Step Ⅴ During the preparation of the black matte polyimide film, the obtained polyamic acid film is peeled off from the endless steel belt, and sent to a N,N'-dimethylacetamide (DMAC) solvent pool at a temperature of 250° C., and Ultrasonic waves with an ultrasonic frequency of 10KHZ and an ultrasonic power of 4.8KW were applied to it, and the hot solvent ultrasonic agglomeration treatment time in the solvent pool was 5s. Other processing methods of this step are identical with embodiment 1 step V.

Detect the light transmittance, gloss, coefficient of thermal expansion (CTE), tensile strength, elongation, modulus, tear strength and indication quality etc. of the black polyimide film that above-mentioned each embodiment and each comparative example make Performance, the results are shown in Table 1:

Table 1 The performance comparison table of the films made by the embodiments of the present invention and comparative examples

As shown in table 1, the black extinction type polyimide film that embodiment 1 to 6 prepares has relatively low glossiness, light transmittance etc. excellent optical property and mechanical property (tensile strength, elongation and modulus). relatively high amount), while also exhibiting high tear resistance (tear strength) and good thermal properties (e.g. CTE, low shrinkage).

However, the black polyimide film prepared in the comparative example ① without thermal solvent ultrasonic agglomeration did not have the expected optical properties, thermal properties and mechanical properties. In comparative examples ② to ⑤, the average particle size of the black pigment and matting agent used is too large or too small, and the optical properties, thermal properties and mechanical properties of the prepared black polyimide film are obviously poor. In comparative example ⑥, the temperature of the hot solvent ultrasonic agglomeration treatment was too high, which resulted in the dissolution of the polyamic acid film and the continuous film formation was impossible. In comparative example ⑦, the thermal solvent ultrasonic agglomeration treatment temperature is too low, the ultrasonic frequency is too small, and the treatment time is short, the agglomeration of fillers such as matting agent and black pigment on the film surface is not obvious, resulting in a high gloss of the film.

The above-mentioned embodiments are only specific examples for further specifying the purpose, technical solutions and beneficial effects of the present invention, and the present invention is not limited thereto. Any modifications, equivalent replacements, improvements, etc. made within the disclosed scope of the present invention are included in the protection scope of the present invention.

Claims (10)

1. a method for preparing a black delustering type polyimide film, comprising the following main steps: Ⅰ. Preparation of polyamic acid resin solution Prepare the polyamic acid resin solution according to the conventional method. In an inert atmosphere, under the condition of controlling the temperature of the synthesis system at 12°C to 75°C, add aromatic diamine to the solvent for stirring and dissolving. After the aromatic diamine is completely dissolved, divide it into 3 Add aromatic dianhydride with a molar ratio of (0.9~1.1):1 to aromatic diamine at a uniform speed for ~8 times, and stir at 120r/min~1200r/min, and synthesize polyamic acid resin solution through polycondensation reaction for 3~24h ; The solvent is an aprotic polar solvent with low molecular weight carboxylamide, specifically N,N'-dimethylacetamide, N,N'-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, Any one or combination of any of tetramethylsulfone, N,N'-dimethyl-N,N'-propenyl urea, N,N dialkylcarboxamide; The amount of the aromatic diamine, aromatic diacid anhydride and solvent is controlled so that the ratio of the solid content M in the polyamic acid resin solution formed in this step is 10wt% to 50wt%; The aromatic diamines are 3,4'-diaminodiphenyl ether, 1,3-bis-(4-aminophenoxy)benzene, 4,4'-diaminodiphenyl ether, 1,3-bis Any one or combination of any of aminobenzene, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-diaminobiphenyl and p-phenylenediamine; The aromatic dianhydride is pyromellitic diacid, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, Diphenyl ether tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 4,4'-oxydiphthalic anhydride , 3,4,3',4'-diphenylsulfide tetracarboxylic dianhydride, 2,3,2',3'-diphenylsulfide tetracarboxylic dianhydride and 2,3,3',4'-di Any one or any combination of phenylene sulfide tetracarboxylic dianhydride; Ⅱ. Black slurry preparation Take the black pigment and add it to the solvent, mix and stir to obtain a black slurry; the amount of the black pigment added is 2wt%～20wt% of the solid content M in the polyamic acid resin solution described in step 1, and the average particle diameter of the black pigment is 0.01～20wt%. 0.8μm; The solvent is an aprotic polar solvent with low molecular weight carboxylamide, specifically N,N'-dimethylacetamide, N,N'-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, Any one or combination of any of tetramethylsulfone, N,N'-dimethyl-N,N'-propenyl urea, N,N dialkylcarboxamide; The amount of solvent used in the black slurry is controlled so that the black pigment content in the black slurry is 10wt% to 30wt%; Ⅲ. Preparation of matting agent dispersion Add the matting agent into the solvent, mix and stir evenly to obtain the matting agent dispersion, the added matting dose is 2wt% to 20wt% of the solid content M in the polyamic acid resin solution described in step I, and the average particle size of the matting agent is 0.01～0.8μm; The solvent is an aprotic polar solvent with low molecular weight carboxylamide, specifically N,N'-dimethylacetamide, N,N'-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, Any one or combination of any of tetramethylsulfone, N,N'-dimethyl-N,N'-propenyl urea, N,N dialkylcarboxamide; The matting agent is any one or a combination of any of silicon dioxide, polyimide, aluminum oxide and titanium dioxide; The amount of solvent used in the matting agent dispersion is controlled so that the content ratio of the matting agent in the matting agent dispersion is 10wt% to 30wt%; Ⅳ. Preparation of black polyamic acid resin solution Take the polyamic acid resin solution obtained in step I, the black slurry obtained in step II and the matting agent dispersion obtained in step III, blend and stir to prepare a black polyamic acid resin solution, and defoam it for later use; Ⅴ. Preparation of black matte polyimide film The black polyamic acid solution prepared in step IV is coated on the endless steel belt through an extrusion molding die, the thickness is 20-520 μm, and then dried at 100-250 ° C to remove 60wt%-35wt% of the solvent to obtain a self-supporting The obtained polyamic acid film is peeled from the endless steel belt and sent into the solvent pool with a temperature of 50°C to 180°C, and an ultrasonic frequency of 20KHZ to 150KHZ and an ultrasonic power of 0.5KW to 3.6KW are applied to it. Ultrasonic, hot solvent ultrasonic agglomeration treatment time in the solvent pool is 10s ~ 180s; The solvent in the high-temperature solvent pool of the hot solvent ultrasonic agglomeration treatment is an aprotic polar solvent low molecular weight carboxamide, specifically N,N'-dimethylacetamide, N,N'-dimethylformamide, N - any one or more of methylpyrrolidone, dimethylsulfoxide, tetramethylsulfone, N,N'-dimethyl-N,N'-propenyl urea, N,N dialkylcarboxamide The combination; The polyamic acid film treated by the hot solvent ultrasonic agglomeration is transported to the vertical and horizontal bidirectional stretching machine for 0.8-2.2 times stretching, 180°C-500°C high-temperature imidization treatment, and finally 180°C-360°C after setting, winding , to prepare a black matte polyimide film with a thickness of 2.5 μm to 50 μm. 2. black matting type polyimide film preparation method according to claim 1, is characterized in that: The amount of the black pigment added in the preparation of the black slurry in the step II is 6wt%-10wt% of M. 3. black extinction type polyimide film preparation method according to claim 1, is characterized in that: The average particle diameter of the black pigment added in the preparation of the black slurry in the step II is 0.02 μm to 0.1 μm. 4. black extinction type polyimide film preparation method according to claim 1, is characterized in that: The amount of the matting agent added in the preparation of the matting agent dispersion in step III is 8wt%-12wt% of M. 5. black matting type polyimide film preparation method according to claim 1, is characterized in that: The average particle size of the matting agent added to the preparation of the matting agent dispersion in step III is 0.05 μm to 0.6 μm. 6. black matting type polyimide film preparation method according to claim 1, is characterized in that: The average particle size of the matting agent added to the preparation of the matting agent dispersion in step III is 0.08 μm to 0.3 μm. 7. according to the preparation method of black matting type polyimide film described in any one in claim 1 to 6, it is characterized in that: The same solvents are used in the preparation of the polyamic acid resin solution in the step I, the preparation of the black slurry in the step II and the preparation of the matting agent dispersion in the step III. 8. black matting type polyimide film preparation method according to claim 1, is characterized in that: In the process of preparing the black matte polyimide film in the step V, the temperature of the hot solvent ultrasonic agglomeration treatment is 60°C-150°C, and the time is 20s-120s. 9. black matting type polyimide film preparation method according to claim 1, is characterized in that: In the process of preparing the black matte polyimide film in the step V, the temperature of the thermal solvent ultrasonic agglomeration treatment is 80° C. to 120° C., and the time is 30s to 60s. 10. according to claim 8 or 9 described black extinction type polyimide film preparation methods, it is characterized in that: The ultrasonic frequency applied is 60KHZ-100KHZ, and the power is 1.8KW-2.8KW.