CN-122011458-A - Preparation method and application of electric breakdown-resistant corona-resistant polyimide film

CN122011458ACN 122011458 ACN122011458 ACN 122011458ACN-122011458-A

Abstract

The invention belongs to the technical field of preparation of electric insulating materials, and discloses a preparation method and application of an electric breakdown-resistant corona-resistant polyimide film. The invention adopts an in-situ polymerization method to prepare the electric breakdown-resistant corona-resistant polyimide film with excellent insulating property by respectively introducing a certain proportion of diamine monomer containing a pyrimidine structure and dianhydride monomer containing a nitrogen heterocyclic structure into a polyimide molecular chain. The DC breakdown field strength of the electric breakdown and corona resistant polyimide film at room temperature is 431.33kV/mm, the AC breakdown field strength at room temperature can reach 308.54kV/mm, and the corona resistant life at high frequency can reach 1305s. The electric breakdown-resistant corona-resistant polyimide film provided by the invention has the characteristics of breakdown resistance, corona resistance, good solution processing feasibility and the like, and the preparation process flow is simple, the cost is low, and the polyimide film can be popularized and implemented.

Inventors

MENG ZHAOTONG
ZHANG JIA
WANG ZHIQIANG
WANG JINJUN
LIU ZIYANG
ZHANG YIWEI
TIAN XU
WANG ZHAOYANG

Assignees

大连理工大学

Dates

Publication Date: 20260512
Application Date: 20260414

Claims (8)

1. The preparation method of the electric breakdown-resistant corona-resistant polyimide film is characterized by comprising the following steps of: Step 1, preparing polyamic acid glue solution: adding 4, 4-diaminodiphenyl ether into N' N-dimethylacetamide, stirring under ice water bath condition to completely dissolve the 4, 4-diaminodiphenyl ether, adding ethylenediamine tetraacetic acid dianhydride and pyromellitic dianhydride, and performing polycondensation reaction under vacuum condition to obtain modified polyamic acid glue solution EPAA; replacing the 4, 4-diaminodiphenyl ether with a mixture of 2-methylthiopyrimidine-4, 6-diamine and 4, 4-diaminodiphenyl ether to obtain a modified polyamic acid glue solution EDPAA; Removing ethylenediamine tetraacetic acid dianhydride in the system of the obtained modified polyamic acid glue EDPAA to obtain modified polyamic acid glue DPAA; step 2, preparing an electric breakdown-resistant corona-resistant polyimide film: and respectively pouring the modified polyamic acid glue solution EPAA, the modified polyamic acid glue solution EDPAA and the modified polyamic acid glue solution DPAA into the surface of a clean glass substrate, coating the glass substrate with an automatic coating machine, naturally cooling to room temperature after the gradient heating process, and demoulding to obtain three electric breakdown-resistant corona-resistant polyimide films.
2. The method for preparing the electric breakdown-resistant corona-resistant polyimide film according to claim 1, wherein, In the step (1), the total mass of 4, 4-diaminodiphenyl ether, ethylenediamine tetraacetic anhydride and pyromellitic dianhydride, the total mass of 2-methylthiopyrimidine-4, 6-diamine, 4-diaminodiphenyl ether, ethylenediamine tetraacetic anhydride and pyromellitic dianhydride, and the volume ratio of the total mass of 2-methylthiopyrimidine-4, 6-diamine, 4-diaminodiphenyl ether and pyromellitic dianhydride to N' N-dimethylacetamide are 3g: (17-27) mL.
3. The method for preparing the electric breakdown-resistant corona-resistant polyimide film according to claim 2, wherein, In the step (1), the ratio of the molar quantity of the 4, 4-diaminodiphenyl ether to the total molar quantity of the ethylenediamine tetraacetic acid dianhydride and the pyromellitic dianhydride is 1 (1.02-1.04), and the mass ratio of the ethylenediamine tetraacetic acid dianhydride to the pyromellitic dianhydride is 1:10, 1:15 and 1:20 respectively; The ratio of the total molar quantity of the 2-methylthiopyrimidine-4, 6-diamine and the 4, 4-diaminodiphenyl ether to the total molar quantity of the ethylenediamine tetraacetic acid dianhydride and the pyromellitic dianhydride is 1 (1.02-1.04), wherein in the synthesized and modified polyamic acid glue solution EDPAA, the mass ratio of the 2-methylthiopyrimidine-4, 6-diamine to the 4, 4-diaminodiphenyl ether is 1:15, and the mass ratio of the ethylenediamine tetraacetic acid dianhydride to the pyromellitic dianhydride is 1:10, 1:15 and 1:20 respectively; The ratio of the total molar quantity of the 2-methylthiopyrimidine-4, 6-diamine and the 4, 4-diaminodiphenyl ether to the molar quantity of the pyromellitic dianhydride is 1 (1.02-1.04), wherein the ratio of the total mass of the 2-methylthiopyrimidine-4, 6-diamine and the 4, 4-diaminodiphenyl ether in the modified polyamic acid glue solution DPAA is 1:10, 1:15 and 1:20 respectively.
4. The method for preparing the electric breakdown-resistant corona-resistant polyimide film according to claim 3, wherein, In the step (1), stirring time is 30-60 min, and the temperature of ice water bath conditions is-5-15 ℃; The vacuum condition is 0-0.02 MPa, and the polycondensation reaction time is 12-14 h.
5. The method for preparing the electric breakdown-resistant corona-resistant polyimide film according to claim 4, wherein, In the step (2), the speed of the coating is 0.2-0.6 cm/s, the time of the coating is 10-30 s, and the length of the coating is 200-250 mm; The gradient heating process comprises the steps of heat preservation at 80 ℃ for 2h, heat preservation at 120 ℃ for lh, heat preservation at 160 ℃ for 1h, heat preservation at 240 ℃ for lh, heat preservation at 300 ℃ for 1h and heat preservation at 350 ℃ for 2h, and the heating rate is 2-4 ℃/min; The demolding environment is a deionized water soaking environment, the demolding temperature is 10-35 ℃, and the demolding time is 15-30 min.
6. The electrical breakdown and corona resistant polyimide film prepared by the preparation method of any one of claims 1-5 has a thickness of 20-30 μm.
7. The use of the electrical breakdown-resistant corona-resistant polyimide film of claim 6 in the manufacture of a film capacitor.
8. The use of the electrical breakdown and corona resistant polyimide film according to claim 7 in the manufacture of film capacitors for high voltage flexible direct current power converter valves, new energy automobile electric automobile inverters, electromagnetic equipment pulse power systems or wind turbine deicing systems.

Description

Preparation method and application of electric breakdown-resistant corona-resistant polyimide film Technical Field The invention belongs to the technical field of preparation of electric insulating materials, and relates to a preparation method and application of an electric breakdown-resistant corona-resistant polyimide film. Background The metallized film capacitor has wide application in the fields of new energy automobiles, high-voltage flexible direct-current transmission, electromagnetic energy equipment, deicing devices and the like by virtue of the advantages of high energy density, faster charge and discharge rate and the like. However, research on the energy storage performance and the insulation performance of the dielectric material in the film capacitor still faces a plurality of bottlenecks, especially in severe working conditions with the height Wen Gaochang such as a high-voltage flexible direct-current transmission converter valve, a new energy automobile electric automobile inverter, an electromagnetic equipment pulse power system, a wind driven generator deicing system and the like. Polyimide (PI) is widely used as an insulating dielectric film with excellent comprehensive performance in important fields such as a winding insulating enameled wire of a driving motor, winding insulation of a high-voltage reactor, dielectric insulating materials of a capacitor and the like. However, with the development of electric and electronic devices in the direction of high power, miniaturization and light weight, the conventional PI film cannot meet the special requirements of modern electric devices, especially the dielectric film of a capacitor, and the PI film is required to have more excellent electrical insulation performance. Therefore, the development of a polyimide thin insulating film having high insulating properties and a process method thereof has become one of important research directions for the power equipment manufacturing industry. Disclosure of Invention The invention provides a preparation method and application of an electric breakdown-resistant corona-resistant polyimide film for solving the technical problem of poor insulating property of a dielectric insulating film of a film capacitor, in particular to application in polyimide intrinsic modification technology, the electric breakdown-resistant corona-resistant polyimide film prepared by the invention creatively introduces an ethyl structure with smaller rotation potential barrier into a main chain, on the one hand, the rigid conjugated structure of the benzene ring can be destroyed, on the other hand, the segment gaps can be filled by rotation, the defect of microscopic pores is reduced, and the polyimide dielectric material with excellent insulating property can be obtained, which has the characteristics of good solution processability, excellent breakdown resistance, longer corona resistant service life and the like. The technical scheme of the invention is as follows: the preparation method of the electric breakdown-resistant corona-resistant polyimide film comprises the following steps: Step 1, preparing polyamic acid glue solution: adding 4, 4-diaminodiphenyl ether into N' N-dimethylacetamide, stirring under ice water bath condition to completely dissolve the 4, 4-diaminodiphenyl ether, adding ethylenediamine tetraacetic acid dianhydride and pyromellitic dianhydride, and performing polycondensation reaction under vacuum condition to obtain modified polyamic acid glue solution EPAA; replacing the 4, 4-diaminodiphenyl ether with a mixture of 2-methylthiopyrimidine-4, 6-diamine and 4, 4-diaminodiphenyl ether to obtain a modified polyamic acid glue solution EDPAA; Removing ethylenediamine tetraacetic acid dianhydride in the system of the obtained modified polyamic acid glue EDPAA to obtain modified polyamic acid glue DPAA; step 2, preparing an electric breakdown-resistant corona-resistant polyimide film: and respectively pouring the modified polyamic acid glue solution EPAA, the modified polyamic acid glue solution EDPAA and the modified polyamic acid glue solution DPAA into the surface of a clean glass substrate, coating the glass substrate with an automatic coating machine, naturally cooling to room temperature after the gradient heating process, and demoulding to obtain three electric breakdown-resistant corona-resistant polyimide films. In the step (1), the total mass of 4, 4-diaminodiphenyl ether, ethylenediamine tetraacetic anhydride and pyromellitic dianhydride, the total mass of 2-methylthiopyrimidine-4, 6-diamine, 4-diaminodiphenyl ether, ethylenediamine tetraacetic anhydride and pyromellitic dianhydride, and the volume ratio of the total mass of 2-methylthiopyrimidine-4, 6-diamine, 4-diaminodiphenyl ether and pyromellitic dianhydride to N' N-dimethylacetamide are 3g: (17-27) mL. In the step (1), the ratio of the molar quantity of the 4, 4-diaminodiphenyl ether to the total molar quantity of the ethylenediamine tetraa