Chemical grafting modified polypropylene capacitor film material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of thin film capacitors, and particularly relates to a chemical grafting modified polypropylene capacitor film material and a preparation method and application thereof. According to the preparation method of the chemical grafting modified polypropylene capacitor film material, provided by the invention, diethylenetriamine ethyl acrylate with a plurality of specific groups such as amino groups and carboxyl groups and unsaturated double bonds is synthesized through esterification reaction, and the diethylenetriamine ethyl acrylate is introduced into a polypropylene material through chemical grafting to obtain chemical grafting modified polypropylene; the prepared polypropylene capacitor film material has the excellent properties of good compatibility, difficulty in film breakage, capability of adsorbing and removing residual moisture, difficulty in oxidation corrosion, excellent breakdown resistance and the like, and the preparation method is a preparation method of the high-performance polypropylene capacitor film material; therefore, the technical problem that a polypropylene capacitor film material prepared in the prior art is low in performance is solved.

Description

Technical Field

[0001] The present application belongs to the technical field of film capacitors, and in particular relates to a chemically grafted modified polypropylene capacitor film material, a preparation method, and an application thereof. Background Art

[0002] Polypropylene film capacitors have the advantages of low dielectric loss, high energy storage density, long cycle life, fast charging and discharging speed, excellent high-frequency characteristics, large working pulse voltage and current, high reliability, and good temperature stability. They can achieve efficient power conversion and energy storage, and polypropylene film capacitors do not produce chemical reactions during the charging and discharging process, and have higher safety and stability. Therefore, polypropylene film capacitors shoulder the task of high-power density energy storage in flexible direct current transmission systems, achieving the smoothing of new energy fluctuations, reducing the impact caused by large-scale new energy grid connection, and ensuring the safe and stable operation of the power grid.

[0003] The base material of polypropylene film capacitor is polypropylene capacitor film material BOPP. Currently, the surface of polypropylene capacitor film material BOPP is usually vacuum-deposited with a metal layer to make a metalized polypropylene film, which is then wound on a mandrel to make a film capacitor core. The film capacitor core is then sprayed with gold metal connection layers at both ends to lead out the electrodes and then packaged into a polypropylene film capacitor; metalized polypropylene film includes single-sided or double-sided metalized polypropylene film. For single-sided metalized polypropylene film, when the single-sided metalized polypropylene film is wound thousands of layers on a mandrel to form a film capacitor core, moisture and air will inevitably be drawn between the layers of the film roll. These moisture and air will increase the risk of failure of the film capacitor. This is mainly because during the use of the film capacitor, factors such as humidity, oxygen and high temperature in the use environment can easily corrode the metallized electrodes on the surface of the film. , causing the metal on its surface to oxidize and form oxides with poor conductivity, which reduces the conductive area of ​​the electrode, reduces the capacity of the capacitor, and even causes the risk of film capacitor failure; currently, in order to remove moisture between the layers of single-sided metallized polypropylene film, the film capacitor core is usually placed in a certain high-temperature closed oven, the temperature is increased and the vacuum is applied to remove the moisture and air between the film layers; however, it is difficult to completely empty the internal moisture through this high temperature and vacuum form. This is because the gap between the film layers is too small, resulting in water and air near the edge of the film capacitor core being easier to remove, but water near the middle of the film capacitor core is difficult to fully remove due to its weak mobility, and is easily retained in the film capacitor core. The residual moisture will cause the internal metal layer to oxidize under long-term operation of the film capacitor, thereby deteriorating its life.

[0004] Although the moisture removal effect can be enhanced by further increasing the temperature and extending the insulation time, the melting point of the polypropylene capacitor film material BOPP itself is not very high, so it is not suitable for this type of moisture removal method. It is necessary to develop new polypropylene capacitor film materials and improve the performance of existing polypropylene capacitor film materials so that they have the ability to remove moisture themselves, thereby reducing the risk of oxidation of the metal layer on the surface of the polypropylene capacitor film material, avoiding performance degradation of the film capacitor core and film capacitor, and extending the service life of the film capacitor core and film capacitor. Summary of the Invention

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

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

[0007] Step S1, esterifying hydroxyethyldiethylenetriamine and ethyl acrylic acid to obtain diethylenetriamine ethyl acrylate; Step S2, chemically grafting diethylenetriamine ethyl acrylate and polypropylene under the initiation of an initiator to obtain chemically grafted modified polypropylene;

[0008] Step S3: melt-blending the chemically grafted modified polypropylene to prepare a chemically grafted modified polypropylene casting sheet, and simultaneously biaxially stretching the sheet to obtain a 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° C., and the time is 1-12 h.

[0010] Preferably, in step S2, the initiator used in the chemical grafting reaction is dibenzoyl peroxide, the temperature is 60-100° C., and the time is 1-8 hours.

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

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

[0013] The second aspect of the present 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 the present application provides a single-sided metallized polypropylene film, comprising the chemically grafted modified polypropylene capacitor film material described in the second aspect and a metal layer;

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

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

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

[0018] The single-sided metallized polypropylene film is wound on a core shaft.

[0019] A fifth aspect of the present application provides a thin film capacitor encapsulated with the thin film capacitor core provided by the fourth aspect.

[0020] The sixth aspect of the present application provides an application of the chemically grafted modified polypropylene capacitor film material described in the second aspect in a film capacitor.

[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. The present application provides a chemically grafted modified polypropylene capacitor film material, in which diethylenetriamine ethyl acrylate having multiple specific groups such as amino groups and carboxyl groups is introduced into polypropylene through chemical grafting; the polypropylene capacitor film material prepared thereby has many excellent properties, such as good compatibility, difficulty in breaking the film, ability to absorb and remove residual moisture, not easy to be oxidized and corroded, and excellent 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 a vapor deposition process, it can be made into a corrosion-resistant, long-life film capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] Figure 1A schematic diagram of a chemical grafting reaction of a chemically grafted modified polypropylene capacitor film material provided in any one of Examples 1-3 of the present application;

[0026] Figure 2 A schematic structural diagram of a film capacitor core made of a chemically grafted modified polypropylene capacitor film material provided in any one of Examples 1-3 of the present application;

[0027] Figure 3 A schematic diagram of a film capacitor core made of a chemically grafted modified polypropylene capacitor film material provided in any one of Examples 1-3 of the present application;

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

[0029] Figure 5 This is a schematic diagram of the chemically grafted modified polypropylene capacitor film material provided in Example 4 of the present application after undergoing oxidation corrosion resistance testing. DETAILED DESCRIPTION

[0030] The present application provides a chemically grafted modified polypropylene capacitor film material, a preparation method, and an application thereof, which are used to solve the technical problem of low performance of polypropylene capacitor film materials prepared in the prior art.

[0031] The following will clearly and completely describe the technical solution of this application in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0032] In view of the low performance of the current polypropylene capacitor film material, the lack of hydration itself, the difficulty in absorbing and removing moisture, the easy corrosion after being made into a film capacitor, the performance degradation and the shortened service life; the present application provides a preparation method of a chemically grafted modified polypropylene capacitor film material; the preparation method comprises: firstly preparing diethylenetriamine ethyl acrylate by esterification reaction of hydroxyethyldiethylenetriamine and ethyl acrylic acid, and then chemically grafting diethylenetriamine ethyl acrylate and polypropylene under the thermal initiation of an initiator (such as Figure 1 The chemically grafted modified polypropylene is obtained by melt blending the chemically grafted modified polypropylene to prepare a chemically grafted modified polypropylene casting sheet and then biaxially stretched to obtain a chemically grafted modified polypropylene capacitor film material.

[0033] In the preparation method of a chemically grafted modified polypropylene capacitor film material provided by the present application, diethylenetriamine ethyl acrylate is introduced into the polypropylene molecular chain; ordinary polypropylene capacitor film materials, as non-polar materials, are difficult to adsorb and remove moisture remaining between film layers, and physical filling with good water absorption filler modification may have compatibility issues with polypropylene capacitor film materials. In addition, the influence of the water absorption filler modification on the polypropylene capacitor film molecular chain must also be considered. Partial filler modification will reduce the material's breakdown resistance and deteriorate its actual performance, which is not conducive to the actual application of polypropylene capacitor film materials in film capacitors. The ideal means of modifying polypropylene capacitor film materials should have the advantages of good compatibility, adsorption and removal of residual moisture, and improvement of the breakdown resistance of polypropylene capacitor film materials. In view of this, the present application first prepares diethylenetriamine ethyl acrylate with special groups through esterification reaction. Diethylenetriamine ethyl acrylate includes multiple water-absorbing groups such as amino and carboxyl groups. The group can effectively remove residual moisture, and at the same time, multiple amino groups also have deep traps to capture carriers, reduce leakage current, improve dielectric properties and breakdown field strength, and the unsaturated double bonds of diethylenetriamineethyl acrylate can also be grafted into the polypropylene molecular chain under the initiation of the initiator, which makes it unnecessary to consider the compatibility of diethylenetriamineethyl acrylate and polypropylene, and diethylenetriamineethyl acrylate can be fully dispersed in the polypropylene capacitor film material; thus, the present application provides a novel structure of diethylenetriamineethyl acrylate modified component, and by chemically grafting it into the polypropylene molecular chain, it can meet the requirements of good compatibility, adsorption and removal of residual moisture, and improvement of the breakdown resistance of the polypropylene capacitor film material, and significantly improve the performance of the polypropylene capacitor film material. Therefore, the preparation method of a chemically grafted modified polypropylene capacitor film material provided in the present application can solve the technical problem of low performance of the polypropylene capacitor film material prepared in the prior art.

[0034] Preferably, in the preparation method of a chemically grafted modified polypropylene capacitor film material provided in the present application, for the esterification process of the diethylenetriamine ethyl acrylate modified component, concentrated sulfuric acid is required as a catalyst, and the reaction is carried out at a temperature of 80~160°C for 1~12 hours to obtain the diethylenetriamine ethyl acrylate modified component.

[0035] Preferably, in a method for preparing a chemically grafted modified polypropylene capacitor film material provided in the present application, the initiation condition for the chemical grafting reaction is thermal initiation, the initiator is dibenzoyl peroxide, and under thermal initiation at a temperature of 60 to 100° C., diethylenetriamine ethyl acrylate and polypropylene are reacted for 1 to 8 hours to obtain chemically grafted modified polypropylene; for the grafting content, calculated by mass, 10 g, 20 g or 30 g of diethylenetriamine ethyl acrylate is added to every 100 g of polypropylene;

[0036] Preferably, the melt blending step after the chemical grafting reaction is to melt blend and extrude the granular chemically grafted modified polypropylene into a modified polypropylene casting sheet, and then a chemically grafted modified polypropylene capacitor film material with a thickness of micron level is obtained through a simultaneous biaxial stretching step.

[0037] Correspondingly, the present application also provides the application of a chemically grafted modified polypropylene capacitor film material prepared as above in a polypropylene film capacitor. The application can be to use a vapor deposition process to cover the upper or lower surface of the material with an aluminum, zinc or aluminum-zinc alloy metal layer to form a metallized polypropylene film; the application can also be to wind the metallized polypropylene film on a core shaft to form a film capacitor core; 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 use epoxy resin or other materials to encapsulate it into a polypropylene film capacitor.

[0038] The chemically grafted modified polypropylene capacitor film material, preparation method and application provided by the present application will be specifically described below with reference to embodiments and experimental examples.

[0039] Example 1

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

[0041] The steps of preparing diethylenetriamine ethyl acrylate include: mixing 100g of hydroxyethyldiethylenetriamine (CAS: 1965-29-3) and 147g of ethyl acrylic acid (CAS: 3586-58-1), adding 1% by mass of concentrated sulfuric acid (concentration 96%), and performing an esterification reaction at 120°C for 6 hours to obtain the product diethylenetriamine ethyl acrylate, and washing the product with anhydrous ethanol to remove residual organic acid and unreacted components.

[0042] The steps of preparing chemically grafted modified polypropylene include: adding 1 kg of Zhongyuan Petrochemical electrical grade ultra-clean polypropylene pellets (ash content 20 ppm, isotactic index 98%) and 4 L of deionized water into an 8 L reactor, sealing it, and circulating nitrogen; adding 30 g of initiator dibenzoyl peroxide BPO, 0.1 kg of diethylenetriamine ethyl acrylate, and 200 mL of xylene into the reactor under nitrogen atmosphere protection and emulsifying them; and then chemically grafting reacting at 80° C. for 4 hours; after the reaction is completed, immersing the obtained chemically grafted modified polypropylene in an ethanol solution and stirring it for 24 hours to remove the diethylenetriamine ethyl acrylate self-polymer therein, filtering to obtain the chemically grafted modified polypropylene, and drying it in a 50° C. oven for later use.

[0043] The steps of preparing a chemically grafted modified polypropylene capacitor film material include: pouring 1 kg of chemically grafted modified polypropylene into a twin-screw extruder, melt-blending and extruding a modified polypropylene casting sheet under melt blending conditions of a screw speed of 28 rad / min and a temperature of 210±5°C, and using a tenter frame to synchronously biaxially stretch the modified polypropylene casting sheet to form a chemically grafted modified polypropylene capacitor film material with a thickness of approximately 10 μm, and collecting a sufficient amount of the polypropylene capacitor film material at a speed of 10 rad / min.

[0044] Example 2

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

[0046] The steps of preparing diethylenetriamine ethyl acrylate include: mixing 200g of hydroxyethyldiethylenetriamine (CAS: 1965-29-3) and 294g of ethyl acrylic acid (CAS: 3586-58-1), adding 1% by mass of concentrated sulfuric acid (concentration 96%), and performing an esterification reaction at 120°C for 6 hours to obtain the product diethylenetriamine ethyl acrylate, and washing the product with anhydrous ethanol to remove residual organic acid and unreacted components.

[0047] The steps of preparing chemically grafted modified polypropylene include: adding 1 kg of Zhongyuan Petrochemical electrical grade ultra-clean polypropylene pellets (ash content 20 ppm, isotactic index 98%) and 4 L of deionized water into an 8 L reactor, sealing it, and circulating nitrogen; adding 30 g of initiator dibenzoyl peroxide BPO, 0.2 kg of diethylenetriamine ethyl acrylate, and 200 mL of xylene into the reactor under nitrogen atmosphere protection and emulsifying them; and then chemically grafting reacting at 80° C. for 4 hours; after the reaction is completed, immersing the obtained chemically grafted modified polypropylene in an ethanol solution and stirring it for 24 hours to remove the diethylenetriamine ethyl acrylate self-polymer therein, filtering to obtain the chemically grafted modified polypropylene, and drying it in a 50° C. oven for later use.

[0048] The steps of preparing a chemically grafted modified polypropylene capacitor film material include: pouring 1 kg of chemically grafted modified polypropylene into a twin-screw extruder, melt-blending and extruding a modified polypropylene casting sheet under melt blending conditions of a screw speed of 28 rad / min and a temperature of 210±5°C, and using a tenter frame to synchronously biaxially stretch the modified polypropylene casting sheet to form a chemically grafted modified polypropylene capacitor film material with a thickness of approximately 10 μm, and collecting a sufficient amount of the polypropylene capacitor film material at a speed of 10 rad / min.

[0049] Example 3

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

[0051] The steps of preparing diethylenetriamine ethyl acrylate include: mixing 200g of hydroxyethyldiethylenetriamine (CAS: 1965-29-3) and 294g of ethyl acrylic acid (CAS: 3586-58-1), adding 1% by mass of concentrated sulfuric acid (concentration 96%), and performing an esterification reaction at 120°C for 6 hours to obtain the product diethylenetriamine ethyl acrylate, and washing the product with anhydrous ethanol to remove residual organic acid and unreacted components.

[0052] The steps of preparing chemically grafted modified polypropylene include: adding 1 kg of Zhongyuan Petrochemical electrical grade ultra-clean polypropylene pellets (ash content 20 ppm, isotactic index 98%) and 4 L of deionized water into an 8 L reactor, sealing it, and circulating nitrogen; adding 30 g of initiator dibenzoyl peroxide BPO, 0.3 kg of diethylenetriamine ethyl acrylate, and 200 mL of xylene into the reactor under nitrogen atmosphere protection and emulsifying them; and then chemically grafting reacting at 80° C. for 4 hours; after the reaction is completed, immersing the obtained chemically grafted modified polypropylene in an ethanol solution and stirring it for 24 hours to remove the diethylenetriamine ethyl acrylate self-polymer therein, filtering to obtain the chemically grafted modified polypropylene, and drying it in a 50° C. oven for later use.

[0053] The steps of preparing a chemically grafted modified polypropylene capacitor film material include: pouring 1 kg of chemically grafted modified polypropylene into a twin-screw extruder, melt-blending and extruding a modified polypropylene casting sheet under melt blending conditions of a screw speed of 28 rad / min and a temperature of 210±5°C, and using a tenter frame to synchronously biaxially stretch the modified polypropylene casting sheet to form a chemically grafted modified polypropylene capacitor film material with a thickness of approximately 10 μm, and collecting a sufficient amount of the polypropylene capacitor film material at a speed of 10 rad / min.

[0054] Example 4

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

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

[0057] Experimental Example 1

[0058] In this Experimental Example 1, the polypropylene capacitor film materials provided in Examples 2 and 4 were subjected to performance tests, and the performance tests included analysis of oxidation corrosion resistance and electrical performance.

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

[0060] The polypropylene capacitor film materials provided in Example 2 and Example 4 were respectively made into single-sided metallized polypropylene films by evaporation process, and then subjected to winding-gold spraying-heat setting treatment to make film capacitor cores. The structural diagram thereof is shown in FIG. Figure 2 As shown, the actual picture is as shown in the instruction manual Figure 3 As shown, it is then packaged into a film capacitor; in the preparation of the film capacitor core, the tension during the winding process is controlled to be a tension coefficient of 1.3, the outsourcing tension coefficient is 0.4~0.6, the core winding speed is limited to 4500r / min~6000r / min, and the gold spraying material is pure zinc wire (purity 99.99%), and the gold spraying pressure is 1.3Mpa±0.3Mpa; heat treatment process: 80℃-10h+90℃-10h+100℃-10h+110℃-10h, and the heating time between different step temperatures is controlled at least 20min.

[0061] The oxidation corrosion resistance test was carried out according to the standard GB / T17702-20215.15. After 200 hours of testing, the film was disassembled and the film was taken out for morphology observation. The results are as follows Figure 4-5 shown; from Figure 5 It can be seen that after the oxidation corrosion resistance test, the polypropylene capacitor film material provided in Example 4 has a large amount of electrode corrosion on its surface, while this phenomenon is not observed on the surface of the polypropylene capacitor film material provided in Example 2 (e.g. Figure 3 As shown), it shows that its excellent water absorption removes the water content inside the polypropylene capacitor film material and inhibits the corrosion of the electrode; at the same time, according to the standard GB / T13542.2-202121.1 test, the results show that the breakdown strength of the polypropylene capacitor film material provided in Example 4 is 557MV m -1 , and the breakdown strength of the polypropylene capacitor film material provided in Example 2 is increased to 652 MV m -1.

[0062] It can be seen from the above experimental results that the present application provides a method for preparing a chemically grafted modified polypropylene capacitor film material; diethylenetriamineethyl acrylate having multiple specific groups such as amino groups and carboxyl groups and unsaturated double bonds is synthesized by esterification reaction, and is successfully introduced into polypropylene with the help of a chemical grafting reaction to obtain a chemically grafted modified polypropylene. The chemically grafted modified polypropylene has good compatibility and is not easy to break when biaxially stretched to make a capacitor film material. It can also absorb and remove residual moisture and is not easily oxidized and corroded, and also improves the breakdown resistance of the capacitor film material. It is a preparation method for a high-performance polypropylene capacitor film material.

[0063] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a chemically grafted modified polypropylene capacitor film material, characterized in that: The following steps are involved: Step S1, esterifying hydroxyethyldiethylenetriamine and ethyl acrylic acid to obtain diethylenetriamine ethyl acrylate; Step S2, chemically grafting diethylenetriamineethyl acrylate and polypropylene under the initiation of an initiator to obtain chemically grafted modified polypropylene; Step S3, melt-blending the chemically grafted modified polypropylene to prepare a chemically grafted modified polypropylene casting sheet, Chemically grafted modified polypropylene capacitor film material was obtained by simultaneous biaxial stretching.

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° C., and the time is 1-12 hours.

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 dibenzoyl peroxide, the temperature is 60-100° C., and the time is 1-8 hours.

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 the diethylenetriamineethyl acrylate to the 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° C., and the screw speed is 28 rad / min.

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

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

8. A film capacitor core, characterized in that: comprising the single-sided metallized polypropylene film and a mandrel as claimed in claim 7; The single-sided metallized polypropylene film is wound on a core shaft.

9. A film capacitor, characterized in that: A film capacitor core according to claim 8 is encapsulated therein.

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

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