Chemically grafted modified polypropylene capacitor film material, preparation method and application thereof

Abstract

The application belongs to the technical field of thin film capacitors, and particularly relates to a chemically grafted modified polypropylene capacitor film material, a preparation method and application. The application provides a preparation method of a chemically grafted modified polypropylene capacitor film material. Diethylenetriamine ethyl acrylate with specific groups such as multiple amino groups, carboxyl groups and unsaturated double bonds is synthesized through esterification reaction, and is introduced into polypropylene material through chemical grafting to obtain chemically grafted modified polypropylene. The prepared polypropylene capacitor film material has good compatibility, is not easy to break the film, can adsorb and remove residual moisture and is not easy to be oxidized and corroded, has superior breakdown resistance and other excellent performances, and is a preparation method of a high-performance polypropylene capacitor film material. Thus, the technical problem of low performance of the prepared polypropylene capacitor film material in the prior art is solved.

Description

Technical Field

[0001] This application belongs to the field of thin-film capacitor technology, and particularly relates to a chemically grafted modified polypropylene capacitor film material, its preparation method, and its application. Background Technology

[0002] Polypropylene film capacitors, due to their advantages such as low dielectric loss, high energy density, long cycle life, fast charging and discharging speed, excellent high-frequency characteristics, large operating pulse voltage and current, high reliability, and good temperature stability, can achieve efficient power conversion and energy storage. Moreover, polypropylene film capacitors do not produce chemical reactions during charging and discharging, thus having higher safety and stability. Therefore, polypropylene film capacitors play a crucial role in high-power-density energy storage in flexible DC transmission systems, helping to mitigate fluctuations in new energy sources, reduce the impact of large-scale new energy grid connection, and ensure the safe and stable operation of the power grid.

[0003] The substrate of polypropylene film capacitors is polypropylene capacitor film material BOPP. Currently, it is common practice to vacuum-deposit a metal layer onto the surface of the BOPP capacitor film material to form a metallized polypropylene film. This metallized polypropylene film is then wound onto a mandrel to form the film capacitor core. Gold metallization layers are then sputtered onto both ends of the film capacitor core to create electrodes, and finally, the film capacitor is encapsulated. Metallized polypropylene films can be single-sided or double-sided. For single-sided metallized polypropylene films, during the process of winding thousands of layers onto a mandrel to form the film capacitor core, moisture and air inevitably get trapped between the layers of the film roll. This moisture and air increase the risk of film capacitor failure, mainly because humidity, oxygen, and high temperatures in the operating environment can easily corrode the metallized electrodes on the film surface during use. This process causes the surface metal to oxidize, forming oxides with poor conductivity. This reduces the conductive area of ​​the electrodes, decreases the capacitance of the capacitor, and may even lead to the failure of the film capacitor. Currently, to remove moisture between the layers of the single-sided metallized polypropylene film, the film capacitor core is usually placed in a high-temperature sealed oven. The temperature is increased and a vacuum is drawn to remove the moisture and air between the film layers. However, this high-temperature and vacuum method is difficult to completely remove the internal moisture. This is because the gaps between the film layers are too small. Water and air near the edges of the film capacitor core are relatively easy to remove, but water near the middle of the film capacitor core has weak mobility and is difficult to remove completely. It is easy for water to remain in the film capacitor core. Under long-term operation, the residual moisture will cause the internal metal layer to oxidize, degrading its lifespan.

[0004] While increasing the temperature and extending the holding time can enhance the moisture removal effect, the melting point of BOPP (polypropylene capacitor film) material is not very high, making it unsuitable for this method. Therefore, it is necessary to develop new BOPP capacitor film materials to improve the performance of existing materials, enabling them to remove moisture themselves. This would reduce the risk of oxidation of the metal layer on the surface of the BOPP capacitor film material, prevent performance degradation of the capacitor core and capacitor, and extend their service life. Summary of the Invention

[0005] In view of this, this application provides a chemically grafted modified polypropylene capacitor film material, its preparation method, and its application, to solve the technical problem of low performance of polypropylene capacitor film materials prepared in the prior art.

[0006] The first aspect of this application provides a method for preparing a chemically grafted modified polypropylene capacitor film material, the method comprising the following steps:

[0007] Step S1: Esterification reaction of hydroxyethyl diethylenetriamine and ethyl acrylic acid to obtain diethylenetriamine ethyl acrylate; Step S2: Chemical grafting reaction of diethylenetriamine ethyl acrylate and polypropylene under the initiation of an initiator to obtain chemically grafted modified polypropylene.

[0008] Step S3: Chemically grafted modified polypropylene is melt-blended to form chemically grafted modified polypropylene castings, and then biaxially stretched to obtain chemically grafted modified polypropylene capacitor film material.

[0009] Preferably, in step S1, the catalyst for the esterification reaction is concentrated sulfuric acid, the temperature is 80~160℃, and the time is 1~12h.

[0010] Preferably, in step S2, the initiator used in the chemical grafting reaction is benzoyl peroxide, the temperature is 60~100℃, and the time is 1~8h.

[0011] Preferably, in step S2, the mass ratio of diethylenetriamine ethyl acrylate to polypropylene is 0.5~4:10.

[0012] Preferably, in step S3, the melt blending temperature is 180~220℃ and the screw speed is 28 rad / min.

[0013] The second aspect of this application provides a chemically grafted modified polypropylene capacitor film material, which is prepared by the preparation method described in the first aspect.

[0014] The third aspect of this application provides a single-sided metallized polypropylene film, comprising a chemically grafted modified polypropylene capacitor film material and a metal layer as described in the second aspect.

[0015] The metal layer covers the upper or lower surface of the polypropylene capacitor film material.

[0016] Preferably, the thickness of the chemically grafted modified polypropylene capacitor film material is 3~20μm, the thickness of the metal layer is 0.05~0.2μm, and the material is zinc, aluminum, or zinc-aluminum alloy.

[0017] The fourth aspect of this application provides a thin-film capacitor core, comprising the single-sided metallized polypropylene film and the mandrel described in the third aspect;

[0018] The single-sided metallized polypropylene film is wound onto a mandrel.

[0019] The fifth aspect of this application provides a thin-film capacitor, which encapsulates the thin-film capacitor core provided in the fourth aspect.

[0020] The sixth aspect of this application provides the application of a chemically grafted modified polypropylene capacitor film material as described in the second aspect in thin-film capacitors.

[0021] Compared with the prior art, the chemically grafted modified polypropylene capacitor film material provided in this application has at least the following beneficial effects:

[0022] 1. This application provides a chemically grafted modified polypropylene capacitor film material, which introduces diethylenetriamine ethyl acrylate with multiple amino and carboxyl groups into polypropylene through chemical grafting; the polypropylene capacitor film material prepared by this method has many excellent properties, such as good compatibility, resistance to film breakage, ability to adsorb and remove residual moisture, resistance to oxidation and corrosion, and superior breakdown resistance.

[0023] 2. The chemically grafted modified polypropylene capacitor film material provided in this application has excellent performance. After being made into a single-sided metallized polypropylene capacitor film using the vapor deposition process, it can be made into a corrosion-resistant and long-life thin film capacitor. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1This is a schematic diagram of the chemical grafting reaction of the chemically grafted modified polypropylene capacitor film material provided in any of the embodiments 1-3 of this application;

[0026] Figure 2 This is a schematic diagram of the structure of a thin-film capacitor core made of chemically grafted modified polypropylene capacitor film material provided in any of the embodiments 1-3 of this application;

[0027] Figure 3 This is a schematic diagram of a thin-film capacitor core made of chemically grafted modified polypropylene capacitor film material provided in any of the embodiments 1-3 of this application;

[0028] Figure 4 A schematic diagram of the chemically grafted modified polypropylene capacitor film material provided in Example 2 of this application after undergoing an oxidation and corrosion resistance test.

[0029] Figure 5 A schematic diagram of the chemically grafted modified polypropylene capacitor film material provided in Example 4 of this application after undergoing oxidation and corrosion resistance tests. Detailed Implementation

[0030] This application provides a chemically grafted modified polypropylene capacitor film material, its preparation method, and its application, which addresses the technical problem of low performance of polypropylene capacitor film materials prepared in the prior art.

[0031] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] Given the current shortcomings of polypropylene capacitor film materials, such as low performance, lack of hydration ability, difficulty in adsorbing and removing moisture, and susceptibility to corrosion, performance degradation, and reduced service life after being made into thin-film capacitors, this application provides a method for preparing chemically grafted modified polypropylene capacitor film materials. The preparation method includes: first, preparing diethylenetriamine ethyl acrylate by esterification of hydroxyethyl diethylenetriamine and ethyl acrylic acid; then, chemically grafting diethylenetriamine ethyl acrylate and polypropylene under thermal initiation with an initiator (e.g., ...). Figure 1 As shown, chemically grafted modified polypropylene was obtained, and then the chemically grafted modified polypropylene was melt-blended to form chemically grafted modified polypropylene cast sheets and simultaneously biaxially stretched to obtain chemically grafted modified polypropylene capacitor film material.

[0033] In the preparation method of chemically grafted modified polypropylene capacitor film material provided in this application, diethylenetriamine ethyl acrylate is introduced into the polypropylene molecular chain. Ordinary polypropylene capacitor film material, as a non-polar material, is difficult to adsorb and remove residual moisture between film layers. Physically filling with highly absorbent fillers may present compatibility issues with the polypropylene capacitor film material. Furthermore, the influence of highly absorbent filler modification on the polypropylene capacitor film molecular chain must be considered; some filler modifications may reduce the material's breakdown resistance, deteriorate its actual performance, and hinder its practical application in film capacitors. An ideal method for modifying polypropylene capacitor film material should possess advantages such as good compatibility, adsorption and removal of residual moisture, and improved breakdown resistance. Therefore, this application first prepares diethylenetriamine ethyl acrylate with special groups through an esterification reaction. Diethylenetriamine ethyl acrylate includes multiple water-absorbing groups such as amino and carboxyl groups. The amino groups effectively remove residual moisture, and multiple amino groups also possess deep traps to capture charge carriers, reduce leakage current, and improve dielectric properties and breakdown field strength. Furthermore, the unsaturated double bonds of diethylenetriamine ethyl acrylate can be grafted into the polypropylene molecular chain under the initiation of an initiator. This eliminates the need to consider the compatibility issues between diethylenetriamine ethyl acrylate and polypropylene, allowing diethylenetriamine ethyl acrylate to be fully dispersed in the polypropylene capacitor film material. Therefore, this application provides a novel diethylenetriamine ethyl acrylate modified component, which, through chemical grafting into the polypropylene molecular chain, can meet multiple requirements such as good compatibility, adsorption and removal of residual moisture, and improved breakdown field strength of the polypropylene capacitor film material, significantly enhancing the performance of the polypropylene capacitor film material. Thus, the preparation method of the chemically grafted modified polypropylene capacitor film material provided in this application can solve the technical problem of low performance of polypropylene capacitor film materials prepared in the prior art.

[0034] As a preferred embodiment, in the preparation method of the chemically grafted modified polypropylene capacitor film material provided in this application, the esterification process of the diethylenetriamine ethyl acrylate modified component requires the use of concentrated sulfuric acid as a catalyst and the reaction at a temperature of 80~160℃ for 1~12h to obtain the diethylenetriamine ethyl acrylate modified component.

[0035] As a preferred embodiment, in the preparation method of the chemically grafted modified polypropylene capacitor film material provided in this application, the initiation condition for the chemical grafting reaction is thermal initiation, the initiator is benzoyl peroxide, and the chemically grafted modified polypropylene is obtained by reacting diethylenetriamine ethyl acrylate and polypropylene for 1 to 8 hours under thermal initiation at a temperature of 60 to 100°C; as for the grafting content, 10g, 20g or 30g of diethylenetriamine ethyl acrylate is added per 100g of polypropylene by mass.

[0036] Preferably, the melt blending step after the chemical grafting reaction is used to melt blend and extrude the granular chemically grafted modified polypropylene into modified polypropylene cast sheets. Subsequently, the chemically grafted modified polypropylene capacitor film material with a thickness in the micrometer range can be obtained through a simultaneous biaxial stretching step.

[0037] Accordingly, this application also provides the application of the chemically grafted modified polypropylene capacitor film material prepared above in polypropylene film capacitors. The application can be to cover the upper or lower surface of the film with an aluminum, zinc or aluminum-zinc alloy metal layer using a vapor deposition process to form a metallized polypropylene film; the application can also be to wind the metallized polypropylene film onto a mandrel to form a film capacitor core; and the application can also be to spray gold metal connection layers at both ends of the film capacitor core to lead out electrodes and then encapsulate it with materials such as epoxy resin to form a polypropylene film capacitor.

[0038] The following will provide a detailed description of the chemically grafted modified polypropylene capacitor film material, its preparation method, and its application, in conjunction with embodiments and experimental examples.

[0039] Example 1

[0040] This embodiment provides a method for preparing chemically grafted modified polypropylene capacitor film material. The preparation method includes the steps of preparing diethylenetriamine ethyl acrylate, preparing chemically grafted modified polypropylene, and preparing chemically grafted modified polypropylene capacitor film material.

[0041] The steps for preparing diethylenetriamine ethyl acrylate include: mixing 100g of hydroxyethyldiethylenetriamine (CAS: 1965-29-3) with 147g of ethyl acrylic acid (CAS: 3586-58-1), adding 1% by mass of concentrated sulfuric acid (96% concentration), and esterifying at 120℃ for 6h to obtain the product diethylenetriamine ethyl acrylate. The product is then washed with anhydrous ethanol to remove residual organic acids and unreacted components.

[0042] The steps for preparing chemically grafted modified polypropylene include: adding 1 kg of Zhongyuan Petrochemical electrical-grade ultra-clean polypropylene granules (ash content 20 ppm, isotactic index 98%) and 4 L of deionized water into an 8 L reactor and sealing it, and circulating nitrogen. Under nitrogen atmosphere protection, 30 g of initiator benzoyl peroxide (BPO), 0.1 kg of diethylenetriamine ethyl acrylate, and 200 mL of xylene are added to the reactor and emulsified. The reaction is carried out at 80 °C for 4 h. After the reaction is completed, the obtained chemically grafted modified polypropylene is soaked in an ethanol solution and stirred for 24 h to remove the diethylenetriamine ethyl acrylate self-polymer. The chemically grafted modified polypropylene is then filtered and dried in an oven at 50 °C for later use.

[0043] The steps for preparing chemically grafted modified polypropylene capacitor film material include: pouring 1 kg of chemically grafted modified polypropylene into a twin-screw extruder, and melt-blending and extruding it into modified polypropylene cast sheets under melt blending conditions of 28 rad / min screw speed and 210±5℃ temperature. Then, using a tenter frame, the modified polypropylene cast sheets are simultaneously biaxially stretched to produce chemically grafted modified polypropylene capacitor film material with a thickness of about 10 μm. Sufficient polypropylene capacitor film material is collected at a speed of 10 rad / min.

[0044] Example 2

[0045] This embodiment provides a method for preparing chemically grafted modified polypropylene capacitor film material. The preparation method includes the steps of preparing diethylenetriamine ethyl acrylate, preparing chemically grafted modified polypropylene, and preparing chemically grafted modified polypropylene capacitor film material.

[0046] The steps for preparing diethylenetriamine ethyl acrylate include: mixing 200g of hydroxyethyldiethylenetriamine (CAS: 1965-29-3) with 294g of ethyl acrylic acid (CAS: 3586-58-1), adding 1% by mass of concentrated sulfuric acid (96% concentration), and esterifying at 120℃ for 6h to obtain the product diethylenetriamine ethyl acrylate. The product is then washed with anhydrous ethanol to remove residual organic acids and unreacted components.

[0047] The steps for preparing chemically grafted modified polypropylene include: adding 1 kg of Zhongyuan Petrochemical electrical-grade ultra-clean polypropylene granules (ash content 20 ppm, isotactic index 98%) and 4 L of deionized water into an 8 L reactor and sealing it, and circulating nitrogen. Under nitrogen atmosphere protection, 30 g of initiator benzoyl peroxide (BPO), 0.2 kg of diethylenetriamine ethyl acrylate, and 200 mL of xylene are added to the reactor and emulsified. The reaction is carried out at 80 °C for 4 h. After the reaction is completed, the obtained chemically grafted modified polypropylene is soaked in an ethanol solution and stirred for 24 h to remove the diethylenetriamine ethyl acrylate self-polymer. The chemically grafted modified polypropylene is then filtered and dried in an oven at 50 °C for later use.

[0048] The steps for preparing chemically grafted modified polypropylene capacitor film material include: pouring 1 kg of chemically grafted modified polypropylene into a twin-screw extruder, and melt-blending and extruding it into modified polypropylene cast sheets under melt blending conditions of 28 rad / min screw speed and 210±5℃ temperature. Then, using a tenter frame, the modified polypropylene cast sheets are simultaneously biaxially stretched to produce chemically grafted modified polypropylene capacitor film material with a thickness of about 10 μm. Sufficient polypropylene capacitor film material is collected at a speed of 10 rad / min.

[0049] Example 3

[0050] This embodiment provides a method for preparing chemically grafted modified polypropylene capacitor film material. The preparation method includes the steps of preparing diethylenetriamine ethyl acrylate, preparing chemically grafted modified polypropylene, and preparing chemically grafted modified polypropylene capacitor film material.

[0051] The steps for preparing diethylenetriamine ethyl acrylate include: mixing 200g of hydroxyethyldiethylenetriamine (CAS: 1965-29-3) with 294g of ethyl acrylic acid (CAS: 3586-58-1), adding 1% by mass of concentrated sulfuric acid (96% concentration), and esterifying at 120℃ for 6h to obtain the product diethylenetriamine ethyl acrylate. The product is then washed with anhydrous ethanol to remove residual organic acids and unreacted components.

[0052] The steps for preparing chemically grafted modified polypropylene include: adding 1 kg of Zhongyuan Petrochemical electrical-grade ultra-clean polypropylene granules (ash content 20 ppm, isotactic index 98%) and 4 L of deionized water into an 8 L reactor and sealing it, and circulating nitrogen. Under nitrogen atmosphere protection, 30 g of initiator benzoyl peroxide (BPO), 0.3 kg of diethylenetriamine ethyl acrylate, and 200 mL of xylene are added to the reactor and emulsified. The reaction is carried out at 80 °C for 4 h. After the reaction is completed, the obtained chemically grafted modified polypropylene is soaked in an ethanol solution and stirred for 24 h to remove the diethylenetriamine ethyl acrylate self-polymer. The polypropylene is then filtered to obtain the chemically grafted modified polypropylene and dried in an oven at 50 °C for later use.

[0053] The steps for preparing chemically grafted modified polypropylene capacitor film material include: pouring 1 kg of chemically grafted modified polypropylene into a twin-screw extruder, and melt-blending and extruding it into modified polypropylene cast sheets under melt blending conditions of 28 rad / min screw speed and 210±5℃ temperature. Then, using a tenter frame, the modified polypropylene cast sheets are simultaneously biaxially stretched to produce chemically grafted modified polypropylene capacitor film material with a thickness of about 10 μm. Sufficient polypropylene capacitor film material is collected at a speed of 10 rad / min.

[0054] Example 4

[0055] This embodiment provides a method for preparing a polypropylene capacitor film material, which includes the step of preparing a chemically grafted modified polypropylene capacitor film material.

[0056] The steps for preparing polypropylene capacitor film material include: pouring 1 kg of polypropylene into a twin-screw extruder, melt-blending and extruding it into polypropylene sheets under melt blending conditions of 28 rad / min screw speed and 210±5℃ temperature, and using a tenter frame to simultaneously biaxially stretch the polypropylene sheets to produce chemically grafted modified polypropylene capacitor film material with a thickness of about 10 μm, and collecting a sufficient amount of polypropylene capacitor film material at a speed of 10 rad / min.

[0057] Experimental Example 1

[0058] Example 1 of this experiment tests the performance of the polypropylene capacitor film materials provided in Examples 2 and 4. The performance tests include analysis of oxidation and corrosion resistance and analysis of electrical performance.

[0059] The process for analyzing oxidation and corrosion resistance and electrical properties is as follows:

[0060] The polypropylene capacitor film materials provided in Examples 2 and 4 were respectively fabricated into single-sided metallized polypropylene films using a vapor deposition process, and then subjected to winding-gold sputtering-heat setting treatment to form film capacitor cores. Their structural schematic diagrams are shown below. Figure 2 As shown in the picture, the actual product image is as described in the instruction manual. Figure 3 As shown, it is then encapsulated into a film capacitor; in the preparation of the film capacitor core, the tension during the winding process is controlled at a tension coefficient of 1.3, the outer wrapping tension coefficient is 0.4~0.6, the core winding speed is limited to 4500r / min~6000r / min, and the gold sputtering material is pure zinc wire (purity 99.99%), the gold sputtering gas pressure is 1.3Mpa±0.3Mpa; the heat treatment process is: 80℃-10h+90℃-10h+100℃-10h+110℃-10h, and the heating time between different temperature steps is controlled to be at least 20min.

[0061] The oxidation and corrosion resistance performance was tested according to standard GB / T17702-20215.15. After 200 hours of testing, the sample was disassembled, and the morphology of the film was observed. The results are as follows. Figure 4-5 As shown; from Figure 5 It can be seen that the polypropylene capacitor film material provided in Example 4 exhibited significant electrode corrosion on its surface after the oxidation and corrosion resistance test, while this phenomenon was not observed on the surface of the polypropylene capacitor film material provided in Example 2 (e.g., Figure 3 As shown in the figure, its excellent water absorption removes the water content inside the polypropylene capacitor film material, inhibiting electrode corrosion. Simultaneously, according to the standard GB / T13542.2-202121.1, the test results show that the breakdown strength of the polypropylene capacitor film material provided in Example 4 is 557 MV m. -1 The breakdown strength of the polypropylene capacitor film material provided in Example 2 is increased to 652 MV m. -1.

[0062] The experimental results above demonstrate that the method for preparing chemically grafted modified polypropylene capacitor film material provided in this application involves synthesizing diethylenetriamine ethyl acrylate with multiple amino and carboxyl groups and unsaturated double bonds through esterification reaction, and successfully introducing it into polypropylene through chemical grafting reaction to obtain chemically grafted modified polypropylene. Due to its good compatibility, this chemically grafted modified polypropylene is not easily damaged when biaxially stretched to form capacitor film material. It can also adsorb and remove residual moisture, is not easily oxidized and corroded, and improves the breakdown resistance of capacitor film material. This is a method for preparing high-performance polypropylene capacitor film material.

[0063] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing a chemically grafted modified polypropylene capacitor film material, characterized in that, Includes the following steps: Step S1: Hydroxyethyldiethylenetriamine and ethyl acrylic acid are subjected to an esterification reaction to obtain diethylenetriamine ethyl acrylate; Step S2: Diethylenetriamine ethyl acrylate and polypropylene are chemically grafted together under the initiation of an initiator to obtain chemically grafted modified polypropylene. Step S3: Melt-blend the chemically grafted modified polypropylene to prepare chemically grafted modified polypropylene cast sheets. Synchronous biaxial stretching yields chemically grafted modified polypropylene capacitor film material.

2. The method for preparing a chemically grafted modified polypropylene capacitor film material according to claim 1, characterized in that, In step S1, the catalyst for the esterification reaction is concentrated sulfuric acid, the temperature is 80~160℃, and the time is 1~12h.

3. The method for preparing a chemically grafted modified polypropylene capacitor film material according to claim 1, characterized in that, In step S2, the initiator used in the chemical grafting reaction is benzoyl peroxide, the temperature is 60~100℃, and the time is 1~8h.

4. The method for preparing a chemically grafted modified polypropylene capacitor film material according to claim 1, characterized in that, In step S2, the mass ratio of diethylenetriamine ethyl acrylate to polypropylene is 0.5~4:

10.

5. The method for preparing a chemically grafted modified polypropylene capacitor film material according to claim 1, characterized in that, In step S3, the melt blending temperature is 180~220℃ and the screw speed is 28r / min.

6. A chemically grafted modified polypropylene capacitor film material, characterized in that, It is prepared by the preparation method according to any one of claims 1-5.

7. A single-sided metallized polypropylene film, characterized in that, Includes a chemically grafted modified polypropylene capacitor film material and a metal layer as described in claim 6; The metal layer covers the upper or lower surface of the chemically grafted modified polypropylene capacitor film material.

8. A thin-film capacitor core, characterized in that, Includes the single-sided metallized polypropylene film and mandrel as described in claim 7; The single-sided metallized polypropylene film is wound onto a mandrel.

9. A thin-film capacitor, characterized in that, The capacitor core of claim 8 is encapsulated.

10. The application of the chemically grafted modified polypropylene capacitor film material according to claim 6 in film capacitors.

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