阅读说明：本技术 聚酰亚胺微粉的制备方法与用途 (Preparation method and application of polyimide micropowder ) 是由 戴美竹 于 2020-12-20 设计创作，主要内容包括：本发明公开了聚酰亚胺微粉的制备方法与用途。先将芳香族有机二酐,催化剂溶解在有机醇溶剂中,在一定温度下酯化反应数小时,然后低温滴入氯化亚砜得到酰卤化物；再将酰卤化物加入到溶解了二胺和催化剂的溶液中得到聚酰胺酸酯；将聚酰胺酸酯通过高压雾化装置喷入高速旋转的沉淀剂溶液中,离心,水洗,烘干得到聚酰亚胺微粉。(The invention discloses a preparation method and application of polyimide micro powder. Firstly, dissolving aromatic organic dianhydride and a catalyst in an organic alcohol solvent, carrying out esterification reaction for several hours at a certain temperature, and then dripping thionyl chloride at a low temperature to obtain acyl halide; then adding acyl halide into the solution in which diamine and catalyst are dissolved to obtain polyamic acid ester; spraying the polyamic acid ester into a precipitator solution rotating at a high speed through a high-pressure atomization device, centrifuging, washing with water, and drying to obtain the polyimide micro powder.)

1. The preparation of the polyimide micro powder comprises the following steps: adding aromatic dianhydride, organic alcohol, catalyst and solvent into a reaction kettle provided with a stirring sleeve set, a temperature controller, an inert gas inlet and an inert gas outlet and a condensation reflux tower, and heating and refluxing for reaction for hours; then, reducing the temperature in the reaction kettle to 0 ℃, dropwise adding thionyl chloride at the temperature of 0-5 ℃, and reacting at room temperature for several hours after dropwise adding to obtain acyl halide; adding diamine, a catalyst and a solvent into the other reaction kettle with a stirring sleeve set, a temperature controller and an inert gas inlet and outlet, controlling the temperature in the kettle to be 0-5 ℃, dripping the prepared acyl halide, stirring for several hours after dripping is finished, and then heating to 25-30 ℃ to react for several hours to obtain a polyamic acid ester solution; injecting the polyamic acid ester solution into high-pressure atomization equipment, and spraying the resin into distilled water containing a precipitator by controlling the atomization pressure and the caliber of a nozzle; and centrifuging, washing and drying the obtained solution to obtain the polyimide micro powder.

2. The aromatic dianhydride according to claim 1, which is one or a mixture of two of 3,3 ', 4, 4' -benzophenone tetracarboxylic dianhydride, 2,3,3 ', 4' -diphenyl ether tetracarboxylic dianhydride, 2, 2-bis (3, 4-dicarboxylic acid) hexafluoropropane dianhydride, 3,3 ', 4, 4' -diphenylsulfone tetracarboxylic dianhydride, 1,2,4, 5-tetracarboxylic dianhydride, 3,3 ', 4, 4' -diphenyl sulfide tetracarboxylic dianhydride, 2,3,3 ', 4' -biphenyl tetracarboxylic dianhydride, 2, 2-bis (3, 4-dicarboxylic acid) isopropane dianhydride; the diamine is one or a mixture of two of 2,2 ' -bis (3-amino-4-phenolic) hexafluoropropane, 4,4 ' -bis (2, 2 ' -bis trifluoromethyl-4-aminophenoxy) benzene, 2,2 ' -bis (3-amino-4-phenolic) isopropane, 4,4 ' -bis (2, 2 ' -bis trifluoromethyl-4-aminophenoxy) biphenyl, 2,2 ' -bis (4-amino-3-phenolic) hexafluoropropane and 3,3 ' -diamino-4, 4 ' -dihydroxydiphenyl sulfide; the organic alcohol is one or a mixture of n-butanol, ethanol and methanol; the catalyst is one or a mixture of two of triethylamine, pyridine, sodium acetate and isoquinoline; the precipitator is one or a mixture of two of polyacrylic acid, polyvinyl alcohol and polymethacrylate; the solvent is one or a mixture of two of tetrahydrofuran, N, N-dimethylacetamide, DMSO and methyl pyrrolidone.

3. The heating reflux time of claim 1 is 2 to 24 hours; after the thionyl chloride is added, reacting at room temperature for 3-5 hours; dropwise adding acyl halide and stirring for 2-24 hours; heating to 25-30 ℃ and reacting for 3-5 hours.

4. The aromatic dianhydride according to claim 1, wherein the molar ratio of the aromatic dianhydride to the organic alcohol to the catalyst to the solvent to the thionyl chloride is as follows: (1.00) (2.05-2.10), (0.01-0.05), (6-10), (2.05-2.1).

5. The diamine, catalyst, solvent and acyl halide of claim 1, wherein the molar ratio of the diamine, catalyst, solvent and acyl halide is as follows: (1.05-1.10), (0.01-0.05), (10-15), (1.00).

6. The pressure range for high pressure atomization according to claim 1 is: 0.5 to 0.7 MPa; the nozzle size is: 0.02-0.1 mm.

7. The drying process according to claim 1 is: 80 ℃/1-2 hours; 120 ℃/1-2 hours; 150 ℃/2-4 hours; 180 ℃/2-4 hours; 220 ℃/4-6 hours; 260 ℃/6-8 hours; 300 ℃/1-2 hours.

8. The particle size range of the polyimide micropowder produced according to claim 1: d10 (1.718-17.846 um), D50 (2.881-35.216 um), and D90 (4.729-59.575 um).

9. The polyimide material with different molecular structures, such as thermoplastic polyimide, thermosetting polyimide, photosensitive polyimide, pressure-sensitive polyimide and the like, containing the polyimide micropowder of claim 1, and industrial applications of interlaminar toughening, resin modification, catalyst carriers and the like of composite materials.

Technical Field

The invention belongs to the technical field of polyimide, and particularly relates to a preparation method and application of polyimide micro powder.

Background

The polyimide micropowder is a high-performance polymer material containing imide functional groups in a series of molecular structures, not only has the characteristics of excellent high temperature resistance, high strength and toughness, corrosion resistance, low dielectric constant and the like, but also has the characteristics of large specific surface area, strong adsorbability, large condensation effect, active surface reaction capacity and the like, shows good application prospects in the fields of interlayer toughening, resin modification, catalyst carriers, photosensitive materials, pressure-sensitive materials, powder metallurgy and the like of composite materials, can also be widely used as substitutes and other effects of automobile parts, electronic components, metals and ceramics, and has been successfully applied to a part of products in the high and new technical fields of aerospace, microelectronics, solar energy, advanced electronic display and the like at present. However, there is still a great technical difficulty in processing polyimide into micron or even nanometer level powder in industrial mass production.

The main methods for preparing the polyimide micropowder at present include emulsion reprecipitation, liquid-liquid phase separation, ultrasonic precipitation, suspension polymerization, physical auxiliary methods and the like, which can prepare a small amount of microspheres, but have defects. Although the emulsion reprecipitation method can prepare polyimide microspheres with the particle size of less than 1 micron, the preparation efficiency of the microspheres is low, and only micro-upgraded dispersion liquid can be prepared once; the liquid-liquid phase separation method realizes the preparation of polyimide micro powder particles by controlling the phase separation of crystalline polyimide, and the polyimide micro powder particles are generally obtained by crystallization of oligomers, so the prepared micro powder particles have smaller molecular weight and poorer mechanical property; the micro powder prepared by suspension polymerization is generally 100-1000 um, but the dispersibility is poor; although a certain amount of polyimide micropowder can be obtained by physical assistance methods such as microwave assistance, the preparation method has low preparation efficiency and high requirements on equipment, and other methods have some defects in the aspects of controlling the particle size and particle size distribution of the polyimide micropowder.

U.S. Pat. No. 4, 6084000,78,78,78,78 provides a method for preparing hollow polyimide microspheres, which comprises adding dianhydride into methanol and ether solvent to synthesize diester diacid, adding diamine, heating to evaporate solvent to obtain polyamic acid, mechanically pulverizing, and treating at high temperature to obtain polyimide micropowder, wherein the size of the polyimide microsphere is 100-1500 μm, and the large particle size limits the difficulty in uniform dispersion during the mixing process of the composite material, thereby affecting the mechanical properties and the consistency of acoustic transmission.

Chai et al (j.polym.sci., PartB: polym.phys.,2003,41:159 to 165) prepared a polyimide resin using diaminodiphenyl ether and diphenyl ether tetracarboxylic dianhydride, and then dissolved in an organic solvent with a dispersant added thereto, can obtain a polyimide fine powder, but since the solubility of the resin is only 2wt%, it is difficult to realize large-scale industrial production.

Chinese patent CN 101089030a discloses a method for preparing polyimide microspheres, which comprises dissolving diamine and dianhydride in an organic solvent to synthesize polyamic acid, adding an imidization accelerator to the polyamic acid to synthesize polyimide, and adding an aqueous solution containing a dispersant dropwise into the polyimide solution. In the method, the dropwise added dispersion liquid cannot be in full contact with all polyimide structures in time, so that the obtained polyimide micro powder has wide particle size distribution and the particle size is difficult to control.

Chinese patent CN103570946 discloses a "method for preparing polyimide microspheres", which comprises synthesizing a polyamic acid solution with a solid content of 10wt% from dianhydride and diamine, diluting the polyamic acid solution to 1wt%, then dripping distilled water to obtain a polyamic acid microsphere solution, and dripping the microsphere solution into a mixed solution containing pyridine and acetic anhydride to obtain polyimide microspheres.

Based on the defects of the prior art, the invention develops a simple method for synthesizing the polyimide micro powder, and the method has simple operation and low requirement on equipment and is suitable for large-scale production.

Disclosure of Invention

The invention discloses a preparation method and application of polyimide micropowder, which is characterized in that the polyimide micropowder with specific particle size and distribution can be obtained by changing the molecular structure and the powder preparation conditions of resin.

The method disclosed by the invention is suitable for preparing various polyimide structures such as thermoplastic polyimide, thermosetting polyimide, photosensitive polyimide, pressure-sensitive polyimide and the like, and industrial application materials such as interlaminar toughening, resin modification, catalyst carriers and the like used as composite materials.

The technical scheme of the invention is as follows: the preparation method and the application of the polyimide micro powder comprise the following specific steps:

adding aromatic dianhydride, organic alcohol, catalyst and solvent into a reaction kettle provided with a stirring sleeve set, a temperature control sleeve set, an inert gas inlet and an inert gas outlet and a condensation reflux tower, and heating and refluxing for reaction for hours; then, reducing the temperature in the reaction kettle to 0 ℃, dropwise adding thionyl chloride at the temperature of 0-5 ℃, and reacting at room temperature for several hours after dropwise adding to obtain acyl halide; adding diamine, a catalyst and a solvent into the other reaction kettle with a stirring sleeve set, a temperature control sleeve set and an inert gas inlet and outlet, controlling the temperature in the kettle to be 0-5 ℃, dripping the prepared acyl halide, stirring for several hours after dripping is finished, and then heating to 25-30 ℃ to react for several hours to obtain a polyamic acid ester solution; injecting the polyamic acid ester solution into high-pressure atomization equipment, and spraying the resin into distilled water containing a precipitator by controlling the atomization pressure and the caliber of a nozzle; and centrifuging, washing and drying the obtained solution to obtain the polyimide micro powder.

The aromatic dianhydride used in the invention is one or a mixture of two of 3,3 ', 4, 4' -benzophenone tetracarboxylic dianhydride, 2,3,3 ', 4' -diphenyl ether tetracarboxylic dianhydride, 2, 2-bis (3, 4-dicarboxylic acid) hexafluoropropane dianhydride, 3,3 ', 4, 4' -diphenylsulfone tetracarboxylic dianhydride, 1,2,4, 5-tetracarboxylic dianhydride, 3,3 ', 4, 4' -diphenyl sulfide tetracarboxylic dianhydride, 2,3,3 ', 4' -biphenyl tetracarboxylic dianhydride and 2, 2-bis (3, 4-dicarboxylic acid) isopropane dianhydride.

The diamine used in the present invention is one or a mixture of two of 2,2 ' -bis (3-amino-4-phenolate) hexafluoropropane, 4,4 ' -bis (2, 2 ' -bis trifluoromethyl-4-aminophenoxy) benzene, 2,2 ' -bis (3-amino-4-phenolate) isopropane, 4,4 ' -bis (2, 2 ' -bis trifluoromethyl-4-aminophenoxy) biphenyl, 2,2 ' -bis (4-amino-3-phenolate) hexafluoropropane, and 3,3 ' -diamino-4, 4 ' -dihydroxybiphenyl sulfide.

The organic alcohol used in the invention is one or a mixture of two of n-butyl alcohol, ethanol and methanol.

The catalyst used in the invention is one or a mixture of two of triethylamine, pyridine, sodium acetate and isoquinoline.

The precipitant used in the invention is one or a mixture of two of polyacrylic acid, polyvinyl alcohol and polymethacrylate.

The solvent used in the invention is one or a mixture of two of tetrahydrofuran, N, N-dimethylacetamide, DMSO, m-cresol and methyl pyrrolidone.

The heating reflux time in the invention is 2-24 hours; after the thionyl chloride is added, the reaction time at room temperature is 3-5 hours; dropwise adding acyl halide and stirring for 2-24 hours; the reaction time after the temperature is raised to 25-30 ℃ is 3-5 hours.

The feeding molar ratio of the aromatic dianhydride, the organic alcohol, the catalyst, the solvent and the thionyl chloride is as follows: (1.00) (2.05-2.10), (0.01-0.05), (6-10), (2.05-2.1).

The feeding molar ratio of the diamine, the catalyst, the solvent and the acyl halide used in the invention is as follows: (1.05-1.10), (0.01-0.05), (10-15), (1.00).

The pressure range of the high-pressure atomization adopted by the invention is as follows: 0.5 to 0.7 MPa; the nozzle size is: 0.02-0.1 mm.

The drying process adopted by the invention comprises the following steps: 80 ℃/1-2 hours; 120 ℃/1-2 hours; 150 ℃/2-4 hours; 180 ℃/2-4 hours; 220 ℃/4-6 hours; 260 ℃/6-8 hours; 300 ℃/1-2 hours.

The particle size range of the polyimide micropowder prepared by the invention is as follows: d10 (1.718-17.846 um), D50 (2.881-35.216 um), and D90 (4.729-59.575 um).

The invention is suitable for preparing polyimide materials with different molecular structures, such as thermoplastic polyimide, thermosetting polyimide, photosensitive polyimide, pressure-sensitive polyimide and the like, and has wide application prospect in the industrial fields of interlayer toughening of composite materials, resin modification, catalyst carriers and the like.

Drawings

FIG. 1 is a particle size distribution diagram of the polyimide micropowder prepared in the first example.

FIG. 2 is a particle size distribution diagram of the polyimide micropowder prepared in example two.

FIG. 3 is a particle size distribution diagram of the polyimide micropowder prepared in example III.

FIG. 4 is a particle size distribution diagram of the polyimide micropowder prepared in example four.

FIG. 5 is a particle size distribution diagram of a polyimide micropowder prepared in example V.

FIG. 6 is a particle size distribution diagram of a polyimide micropowder prepared in example six.

Detailed Description

The first embodiment is as follows: adding 515.6g of 3,3 ', 4, 4' -benzophenonetetracarboxylic dianhydride, 237.2g of N-butanol, 8g of triethylamine and 1200g of N-methylpyrrolidone into a 5L enamel reaction kettle provided with a stirring sleeve set, a temperature control sleeve set, an inert gas protection device and a condensation reflux device, heating to 75-80 ℃, stirring and refluxing for 12 hours, and then reducing the temperature of the solution to 0 ℃; keeping the temperature of the solution within the range of 0-5 ℃, starting to dropwise add 384.4g of thionyl chloride, and stirring and reacting at normal temperature for 3 hours after dropwise addition is finished to obtain an acyl chloride compound; adding 2100g of N-methylpyrrolidone, 585.3g of 2,2 '-bis (3-amino-4-phenolic) hexafluoropropane and 455.6g of pyridine into another 5L enamel reaction kettle provided with a stirring sleeve, a temperature control sleeve and an inert gas protection device, stirring until the N-methylpyrrolidone, the 2, 2' -bis (3-amino-4-phenolic) hexafluoropropane and the pyridine are completely dissolved, cooling the solution to 0-5 ℃ by adopting an ice water bath, then dripping acyl chloride compounds into the solution, keeping stirring at a low temperature for reacting for 4 hours after dripping is finished, and then heating to room temperature and stirring for 3 hours to obtain a polyamic acid ester resin; injecting the resin into high-pressure atomization equipment, adjusting the atomization pressure to be 0.5MPa, spraying the resin into polyacrylic acid aqueous solution which is stirred at high speed by adopting a nozzle with the caliber of 0.1mm, then centrifugally desolventizing, washing for multiple times, and drying by controlling the temperature in stages to obtain the polyimide micropowder. The particle size data of the micro powder is as follows: d10=17.846um, D50=35.216um, D90=59.575um, and the specific particle size distribution is shown in figure 1.

Example two: adding 497g of 2,3,3 ', 4' -diphenyl ether tetracarboxylic dianhydride, 75g of ethanol, 119g of butanol, 8g (0.08 mol) of triethylamine and 1200g of N-methylpyrrolidone into a 5L enamel reaction kettle provided with a stirring sleeve set, a temperature control sleeve set, an inert gas protection device and a condensation reflux device, heating to 75-80 ℃, and cooling the solution to 0 ℃ after stirring reflux reaction for 12 hours; keeping the temperature of the solution within the range of 0-5 ℃, starting to dropwise add 384.4g of thionyl chloride, and stirring and reacting at normal temperature for 3 hours after dropwise addition is finished to obtain an acyl chloride compound; adding 2100g of N-methylpyrrolidone, 585.3g of 2,2 '-bis (3-amino-4-phenolic) hexafluoropropane and 455.6g of pyridine into another 5L enamel reaction kettle provided with a stirring sleeve, a temperature control sleeve and an inert gas protection device, stirring until the N-methylpyrrolidone, the 2, 2' -bis (3-amino-4-phenolic) hexafluoropropane and the pyridine are completely dissolved, cooling the solution to 0-5 ℃ by adopting an ice water bath, then dripping acyl chloride compounds into the solution, keeping stirring at a low temperature for reacting for 4 hours after dripping is finished, and then heating to room temperature and stirring for 3 hours to obtain a polyamic acid ester resin; injecting the resin into high-pressure atomization equipment, adjusting the atomization pressure to be 0.5MPa, spraying the resin into polyacrylic acid aqueous solution which is stirred at high speed by adopting a nozzle with the caliber of 0.1mm, then centrifugally desolventizing, washing for multiple times, and drying by controlling the temperature in stages to obtain the polyimide micropowder. The particle size data of the micro powder is as follows: d10=7.667um, D50=16.363um, D90=42.327um, and the specific particle size distribution is shown in figure 2.

Example three: adding 344g of 3,3 ', 4, 4' -benzophenonetetracarboxylic dianhydride, 807.3g of 2, 2-bis (3, 4-dicarboxylic acid) hexafluoropropane dianhydride, 237.2g of N-butanol, 8g of triethylamine and 1000g of N-methylpyrrolidone into a 5L enamel reaction kettle provided with a stirring sleeve set, a temperature control sleeve set, an inert gas protection device and a condensing reflux device, heating to 75-80 ℃, and carrying out stirring reflux reaction for 12 hours to reduce the temperature of the solution to 0 ℃; keeping the temperature of the solution within the range of 0-5 ℃, starting to dropwise add 384.4g of thionyl chloride, and stirring and reacting at normal temperature for 3 hours after dropwise addition is finished to obtain an acyl chloride compound; adding 2100g of N-methylpyrrolidone, 585.3g of 2,2 '-bis (3-amino-4-phenolic) hexafluoropropane and 455.6g of pyridine into another 5L enamel reaction kettle provided with a stirring sleeve, a temperature control sleeve and an inert gas protection device, stirring until the N-methylpyrrolidone, the 2, 2' -bis (3-amino-4-phenolic) hexafluoropropane and the pyridine are completely dissolved, cooling the solution to 0-5 ℃ by adopting an ice water bath, then dripping acyl chloride compounds into the solution, keeping stirring at a low temperature for reacting for 4 hours after dripping is finished, and then heating to room temperature and stirring for 3 hours to obtain a polyamic acid ester resin; injecting the resin into high-pressure atomization equipment, adjusting the atomization pressure to be 0.55MPa, spraying the resin into polyacrylic acid aqueous solution which is stirred at high speed by adopting a nozzle with the caliber of 0.1mm, then centrifugally desolventizing, washing for multiple times, and drying by controlling the temperature in stages to obtain the polyimide micropowder. The particle size data of the micro powder is as follows: d10=7.741um, D50=11.011um, D90=15.577um, and the specific particle size distribution is shown in figure 3.

Example four: adding 3,3 ', 4' -diphenyl sulfone tetracarboxylic dianhydride 573.3, N-butyl alcohol 119.6g, ethanol 73.7g, triethylamine 8g and N-methyl pyrrolidone 1200g into a 5L enamel reaction kettle provided with a stirring sleeve set, a temperature control sleeve set, an inert gas protection device and a condensation reflux device, heating to 75-80 ℃, stirring and refluxing for 12 hours, and then cooling the solution to 0 ℃; keeping the temperature of the solution within the range of 0-5 ℃, starting to dropwise add 384.4g of thionyl chloride, and stirring and reacting at normal temperature for 3 hours after dropwise addition is finished to obtain an acyl chloride compound; adding 2100g of N-methylpyrrolidone, 585.3g of 2,2 '-bis (3-amino-4-phenolic) hexafluoropropane and 455.6g of pyridine into another 5L enamel reaction kettle provided with a stirring sleeve, a temperature control sleeve and an inert gas protection device, stirring until the N-methylpyrrolidone, the 2, 2' -bis (3-amino-4-phenolic) hexafluoropropane and the pyridine are completely dissolved, cooling the solution to 0-5 ℃ by adopting an ice water bath, then dripping acyl chloride compounds into the solution, keeping stirring at a low temperature for reacting for 4 hours after dripping is finished, and then heating to room temperature and stirring for 3 hours to obtain a polyamic acid ester resin; injecting the resin into high-pressure atomization equipment, adjusting the atomization pressure to be 0.55MPa, spraying the resin into polyacrylic acid aqueous solution which is stirred at high speed by adopting a nozzle with the caliber of 0.04mm, then centrifugally desolventizing, washing for multiple times, and drying by controlling the temperature in stages to obtain the polyimide micropowder. The particle size data of the micro powder is as follows: d10=4.807um, D50=6.926um, D90=9.932um, and the specific particle size distribution is shown in figure 4.

Example five: adding 807.3g of 2, 2-bis (3, 4-dicarboxylic acid) hexafluoropropane dianhydride, 286.6g of 3,3 ', 4' -diphenylsulfone tetracarboxylic dianhydride, 147g of ethanol, 8g of triethylamine and 1200g of N-methylpyrrolidone into a 5L enamel reaction kettle provided with a stirring sleeve set, a temperature control sleeve set, an inert gas protection device and a condensation reflux device, heating to 75-80 ℃, and carrying out stirring reflux reaction for 12 hours to reduce the temperature of the solution to 0 ℃; keeping the temperature of the solution within the range of 0-5 ℃, starting to dropwise add 384.4g of thionyl chloride, and stirring and reacting at normal temperature for 3 hours after dropwise addition is finished to obtain an acyl chloride compound; adding 2100g of N-methylpyrrolidone, 585.3g of 2,2 '-bis (3-amino-4-phenolic) hexafluoropropane and 455.6g of pyridine into another 5L enamel reaction kettle provided with a stirring sleeve, a temperature control sleeve and an inert gas protection device, stirring until the N-methylpyrrolidone, the 2, 2' -bis (3-amino-4-phenolic) hexafluoropropane and the pyridine are completely dissolved, cooling the solution to 0-5 ℃ by adopting an ice water bath, then dripping acyl chloride compounds into the solution, keeping stirring at a low temperature for reacting for 4 hours after dripping is finished, and then heating to room temperature and stirring for 3 hours to obtain a polyamic acid ester resin; injecting the resin into high-pressure atomization equipment, adjusting the atomization pressure to be 0.6MPa, adopting a nozzle with the caliber of 0.04mm, spraying the resin into a polyvinyl alcohol aqueous solution stirred at a high speed, then centrifugally desolventizing, washing for multiple times, and drying by controlling the temperature in stages to obtain the polyimide micropowder. The particle size data of the micro powder is as follows: d10=1.796um, D50=4.049um, D90=8.655um, and the specific particle size distribution is shown in figure 5.

Example six: adding 515.6g (1.6 mol) of 3,3 ', 4, 4' -benzophenonetetracarboxylic dianhydride, 237.2g (3.2mol) of butanol, 8g (0.08 mol) of triethylamine and 1200g of N-methylpyrrolidone into a 5L enamel reaction kettle provided with a stirring sleeve set, a temperature control sleeve set, an inert gas protection device and a condensation reflux device, heating to 75-80 ℃, and carrying out stirring reflux reaction for 12 hours to reduce the temperature of the solution to 0 ℃; keeping the temperature of the solution within the range of 0-5 ℃, starting to dropwise add 384.4g (3.232 mol) of thionyl chloride, and stirring and reacting at normal temperature for 3 hours after dropwise addition to obtain an acyl chloride compound; adding 1000g of tetrahydrofuran, 1000g of N-methylpyrrolidone, 256.2g of 4,4 ' -bis (2, 2 ' -bis (trifluoromethyl-4-aminophenoxy) biphenyl, 293.0g of 2,2 ' -bis (4-amino-3-phenol) hexafluoropropane and 455.6g of pyridine into another 5L enamel reaction kettle provided with a stirring sleeve set, a temperature control sleeve set and an inert gas protection device, stirring until the mixture is completely dissolved, cooling the solution to 0-5 ℃ by adopting an ice water bath, then dripping an acyl chloride compound into the solution, keeping stirring at a low temperature for reaction for 4 hours after dripping is finished, and then heating to room temperature and stirring for 3 hours to obtain a polyamide ester resin; injecting the resin into high-pressure atomization equipment, adjusting the atomization pressure to be 0.65MPa, adopting a nozzle with the caliber of 0.04mm, spraying the resin into a polyvinyl alcohol aqueous solution stirred at a high speed, then centrifugally desolventizing, washing for multiple times, and drying by controlling the temperature in stages to obtain the polyimide micropowder. The particle size data of the micro powder is as follows: d10=1.718um, D50=2.881um, D90=4.729um, and the specific particle size distribution is shown in figure 6.