Physical modified polypropylene capacitor film material and preparation method and application thereof
By introducing maleic anhydride grafted polypropylene and para-aminobenzoic polar filler into the polypropylene capacitor film material, the problem of water removal difficulties in polypropylene capacitor film material is solved, and a high-performance film capacitor is realized, which extends the service life and improves the dielectric performance.
Patent Information
- Application Number
- CN202510860688.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-25
- Publication Date
- 2025-08-12
AI Technical Summary
The existing polypropylene capacitor film materials have low performance and are difficult to effectively remove moisture, resulting in film capacitors being easily corroded in high humidity environments and shorten their lifespan.
Using physically modified polypropylene capacitor film materials, by introducing maleic anhydride grafted polypropylene and para-aminobenzoic polar fillers, water is adsorbed by polar groups such as amino groups and carboxyl groups, and by grafting maleic anhydride polypropylene to promote uniform dispersion of polar fillers in polypropylene, improving dielectric properties and breakdown resistance.
Effectively adsorbate and remove moisture, reduce corrosion risks, extend the life of film capacitors, improve dielectric performance and breakdown resistance, and make a high-life film capacitor with corrosion resistance.
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Figure CN120464083A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of film capacitors, and in particular relates to a physically 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, achieve the smoothing of new energy fluctuations, reduce the impact of large-scale new energy grid connection, and ensure the safe and stable operation of the power grid, playing a key supporting role in the development of new energy in my country.
[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 physically modified polypropylene capacitor film material, a preparation method and an application thereof, to solve the technical problem of low performance of polypropylene capacitor film materials in the prior art.
[0006] In a first aspect, the present application provides a physically modified polypropylene capacitor film material, the raw materials of which include: polypropylene, maleic anhydride grafted polypropylene, and para-aminobenzoic acid polar filler.
[0007] Preferably, calculated in parts by mass, the composition comprises 80-120 parts by mass of polypropylene, 8-12 parts by mass of maleic anhydride grafted polypropylene, and 1-10 parts by mass of p-aminobenzoic acid polar filler.
[0008] Preferably, calculated in parts by mass, it includes 90 parts by mass of polypropylene, 10 parts by mass of maleic anhydride grafted polypropylene and 5 parts by mass of p-aminobenzoic acid polar filler.
[0009] A second aspect of the present application provides a method for preparing a physically modified polypropylene capacitor film material, the preparation method comprising the following steps:
[0010] Step S1, physically blending polypropylene and maleic anhydride grafted polypropylene to prepare a polypropylene substrate;
[0011] Step S2, physically blending the polypropylene substrate and the p-aminobenzoic acid polar filler to prepare a p-aminobenzoic acid / polypropylene composite material;
[0012] Step S3: melt-blending the p-aminobenzoic acid / polypropylene composite material to prepare a physically modified polypropylene casting sheet, and simultaneously biaxially stretching the sheet to obtain a physically modified polypropylene capacitor film material.
[0013] Preferably, in step S1, the physical blending process is: adding polypropylene and maleic anhydride grafted polypropylene into a high-speed mixer, and physically blending them at a speed of 1000-1500 r / min for 5-20 min.
[0014] Preferably, in step S2, the physical blending process is: adding the polypropylene substrate and the p-aminobenzoic acid polar filler into a ball milling jar of a ball mill, and ball milling them at a speed of 300 rpm for 6 to 8 hours for physical blending.
[0015] Preferably, in step S3, the melt blending process is: adding the p-aminobenzoic acid / polypropylene composite material into a twin-screw extruder, and melt blending at a melt temperature of 210-250° C. and a screw speed of 28 rad / min.
[0016] A third aspect of the present application provides a single-sided metallized polypropylene film, comprising the physically modified polypropylene capacitor film material described in the first aspect and a metal layer;
[0017] The metal layer covers the upper surface or the lower surface of the polypropylene capacitor film material.
[0018] Preferably, the physically modified polypropylene capacitor film material has a thickness of 3-20 μm, the metal layer has a thickness of 0.05-0.2 μm, and the material is zinc, aluminum, or zinc-aluminum alloy.
[0019] 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;
[0020] The single-sided metallized polypropylene film is wound on a core shaft.
[0021] A fifth aspect of the present application provides a thin film capacitor encapsulated with the thin film capacitor core provided by the fourth aspect.
[0022] The sixth aspect of the present application provides the use of the physically modified polypropylene capacitor film material described in the first aspect in a film capacitor.
[0023] Compared with the prior art, the physically modified polypropylene capacitor film material provided in this application has at least the following beneficial effects:
[0024] 1. The present application provides a physically modified polypropylene capacitor film material, which can absorb and remove moisture by introducing p-aminobenzoic acid, thereby reducing the risk of corrosion of film capacitors and increasing the service life of film capacitors. By using maleic anhydride grafted polypropylene as a bridge, the polar filler p-aminobenzoic acid is evenly dispersed in the polypropylene, thereby improving the dielectric properties of the capacitor film material and making it more resistant to breakdown.
[0025] 2. The physically 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
[0026] 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.
[0027] Figure 1 A schematic structural diagram of a film capacitor core made of a physically modified polypropylene capacitor film material provided in Example 2 of the present application;
[0028] Figure 2 A schematic diagram of a film capacitor core made of the physically modified polypropylene capacitor film material provided in Example 2 of the present application;
[0029] Figure 3 A schematic diagram of the physically modified polypropylene capacitor film material provided in Example 2 of the present application after undergoing oxidation corrosion resistance testing;
[0030] Figure 4 This is a schematic diagram of the polypropylene capacitor film material provided in Example 4 of the present application after undergoing oxidation corrosion resistance testing. DETAILED DESCRIPTION
[0031] The present application provides a physically 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 in the prior art.
[0032] 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.
[0033] In view of the low performance of the current polypropylene capacitor film material, its own lack of hydration, its difficulty in adsorbing and removing moisture, its easy corrosion after being made into a film capacitor, its performance degradation and its shortened service life; the present application provides a physically modified polypropylene capacitor film material; the raw material composition of the physically modified polypropylene capacitor film material includes: polypropylene, maleic anhydride grafted polypropylene and para-aminobenzoic acid polar filler; the introduced para-aminobenzoic acid polar filler molecules include multiple polar groups such as amino and carboxyl groups, and can adsorb water molecules through hydrogen bonds, thereby giving the polypropylene capacitor film material hydration, which is used to adsorb and remove moisture, reduce the risk of film capacitor corrosion, and increase the service life of the film capacitor; and the polar filler is introduced into the non-polar polypropylene capacitor film material by physical mixing. Since it is difficult to achieve dispersion at the molecular level, it will bring about an interface effect, poor compatibility between the polar filler and the polypropylene capacitor film material, small-scale agglomeration of the polar filler leads to local electric field distortion, causing an increase in leakage current, making the polypropylene capacitor film material more susceptible to corrosion. Breakdown strength, and the present application simultaneously fills p-aminobenzoic acid as a polar filler and maleic anhydride grafted polypropylene into a non-polar polypropylene capacitor film material, maleic anhydride grafted polypropylene can be used as a compatibilizer to make the polar filler p-aminobenzoic acid uniformly dispersed in the polypropylene, thereby improving the polarity of the capacitor film material, improving the dielectric properties of the capacitor film material, making it more resistant to breakdown, and improving the energy storage density. It can also avoid the risk of local electric field distortion caused by agglomeration of polar fillers, which causes an increase in leakage current and makes it more susceptible to breakdown strength; thus, the physically modified polypropylene capacitor film material provided by the present application simultaneously fills p-aminobenzoic acid and maleic anhydride grafted polypropylene as polar fillers into a non-polar polypropylene capacitor film material, which can effectively adsorb and remove moisture between film layers on the one hand, and improve its dielectric properties on the other hand, and the polypropylene capacitor film is not easily broken down. Therefore, the present application provides a high-performance polypropylene capacitor film material through physical modification, which can solve the technical problem of low performance of polypropylene capacitor film materials in the prior art.
[0034] As a preference, for the amount of raw materials such as polypropylene, maleic anhydride grafted polypropylene and p-aminobenzoic acid polar filler in the physically modified polypropylene capacitor film material; although maleic anhydride grafted polypropylene is used as a bridge, it shows good compatibility with p-aminobenzoic acid and polypropylene. In theory, the use of all maleic anhydride grafted polypropylene can maximize the dispersibility of p-aminobenzoic acid in the matrix, but the economic benefit is poor. Therefore, in this application, 10wt% of maleic anhydride grafted polypropylene is selected, that is, 90 parts by mass of polypropylene and 10 parts by mass of maleic anhydride grafted polypropylene are grafted. Propylene is compounded into a polypropylene substrate, taking into comprehensive consideration the cost and performance of the polypropylene capacitor film material, and the amount of p-aminobenzoic acid polar filler used is 1wt%~10wt% of the polypropylene substrate, that is, 100 parts by mass of polypropylene substrate and 1~10 parts by mass of p-aminobenzoic acid polar filler are compounded; 5wt% of the p-aminobenzoic acid polar filler is a more appropriate addition amount. On the one hand, the addition amount of 5wt% has good water absorption performance and effectively absorbs and removes moisture in the gaps of the film. On the other hand, no agglomeration will occur to form structural weak areas, and the mechanical and electrical properties will not be deteriorated.
[0035] At the same time, this application provides a method for preparing the above-mentioned physically modified polypropylene capacitor film material.
[0036] The preparation method includes melt blending. At room temperature, the p-aminobenzoic acid polar filler is a solid powder with a melting point of about 180°C, which is close to the melting points of polypropylene and maleic anhydride grafted polypropylene, so that they can be effectively mixed during melt blending. The use of the p-aminobenzoic acid polar filler avoids the defect that polar fillers with high melting points are difficult to melt and mix evenly. The preparation method includes first physically mixing polypropylene and maleic anhydride grafted polypropylene to form a polypropylene base material, then ball milling and blending the polypropylene base material and the p-aminobenzoic acid polar filler to form a p-aminobenzoic acid / polypropylene composite material, and then placing it in a 50°C oven to dry for use; then, melt blending the p-aminobenzoic acid / polypropylene composite material and synchronously biaxially stretching it to form a physically modified polypropylene capacitor film material, and the thickness of the polypropylene capacitor film material is at the micron level.
[0037] Correspondingly, the present application also provides the application of the above-mentioned physically modified polypropylene capacitor film material in polypropylene film capacitors. 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 make a metallized polypropylene film; the application can also be to wind the metallized polypropylene film on a core shaft to make a film capacitor core; the application can also be to spray gold metal connecting 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 physically 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 physically modified polypropylene capacitor film material, which includes the steps of preparing a polypropylene substrate, preparing a p-aminobenzoic acid / polypropylene composite material, and preparing a physically modified polypropylene capacitor film material.
[0041] The steps of preparing the polypropylene substrate include: placing 1.8 kg of electrical grade ultra-clean polypropylene powder (ash content 15 ppm, isotactic index 98%) and 0.2 kg of maleic anhydride grafted polypropylene powder in a high-speed mixer at a speed of 1200 r / min and mixing for 10 minutes to obtain the polypropylene substrate.
[0042] The steps of preparing a p-aminobenzoic acid / polypropylene composite material include: placing 0.02 kg of p-aminobenzoic acid polar filler and 2 kg of polypropylene substrate in a ball mill of a ball mill, using anhydrous ethanol as a ball milling medium, and ball milling at a speed of 300 rpm for 6 to 8 hours to obtain a p-aminobenzoic acid / polypropylene composite material, and placing it in a 50°C oven to dry for use.
[0043] The steps of preparing a physically modified polypropylene capacitor film material include: pouring approximately 2 kg of a p-aminobenzoic acid / polypropylene composite material into a twin-screw extruder, melt-blending and extruding it into a modified polypropylene casting sheet under melt blending conditions of a screw speed of 28 rad / min and a temperature of 230±5°C, and using a tenter frame to synchronously biaxially stretch the modified polypropylene casting sheet to form a physically 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 physically modified polypropylene capacitor film material, which includes the steps of preparing a polypropylene substrate, preparing a p-aminobenzoic acid / polypropylene composite material, and preparing a physically modified polypropylene capacitor film material.
[0046] The steps of preparing the polypropylene substrate include: placing 1.8 kg of electrical grade ultra-clean polypropylene powder (ash content 15 ppm, isotactic index 98%) and 0.2 kg of maleic anhydride grafted polypropylene powder in a high-speed mixer at a speed of 1200 r / min and mixing for 10 minutes to obtain the polypropylene substrate.
[0047] The steps of preparing a p-aminobenzoic acid / polypropylene composite material include: placing 0.1 kg of p-aminobenzoic acid polar filler and 2 kg of polypropylene substrate in a ball mill of a ball mill, using anhydrous ethanol as a ball milling medium, and ball milling at a speed of 300 rpm for 6 to 8 hours to obtain a p-aminobenzoic acid / polypropylene composite material, and placing it in a 50°C oven to dry for use.
[0048] The steps of preparing a physically modified polypropylene capacitor film material include: pouring approximately 2 kg of a p-aminobenzoic acid / polypropylene composite material into a twin-screw extruder, melt-blending and extruding it into a modified polypropylene casting sheet under melt blending conditions of a screw speed of 28 rad / min and a temperature of 230±5°C, and using a tenter frame to synchronously biaxially stretch the modified polypropylene casting sheet to form a physically 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 physically modified polypropylene capacitor film material, which includes the steps of preparing a polypropylene substrate, preparing a p-aminobenzoic acid / polypropylene composite material, and preparing a physically modified polypropylene capacitor film material.
[0051] The steps of preparing the polypropylene substrate include: placing 1.8 kg of electrical grade ultra-clean polypropylene powder (ash content 15 ppm, isotactic index 98%) and 0.2 kg of maleic anhydride grafted polypropylene powder in a high-speed mixer at a speed of 1200 r / min and mixing for 10 minutes to obtain the polypropylene substrate.
[0052] The steps of preparing a p-aminobenzoic acid / polypropylene composite material include: placing 0.2 kg of p-aminobenzoic acid polar filler and 2 kg of polypropylene substrate in a ball mill of a ball mill, using anhydrous ethanol as a ball milling medium, and ball milling at a speed of 300 rpm for 6 to 8 hours to obtain a p-aminobenzoic acid / polypropylene composite material, and placing it in a 50°C oven to dry for use.
[0053] The steps of preparing a physically modified polypropylene capacitor film material include: pouring approximately 2 kg of a p-aminobenzoic acid / polypropylene composite material into a twin-screw extruder, melt-blending and extruding it into a modified polypropylene casting sheet under melt blending conditions of a screw speed of 28 rad / min and a temperature of 230±5°C, and using a tenter frame to synchronously biaxially stretch the modified polypropylene casting sheet to form a physically 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. As a comparative example for Examples 1-3, the preparation method comprises the following steps: pouring approximately 2 kg of electrical-grade ultra-clean polypropylene powder (ash content 15 ppm, isotactic index 98%) into a twin-screw extruder, melt-blending and extruding the powder into a polypropylene sheet at a screw speed of 28 rad / min and a temperature of 230±5°C, and simultaneously biaxially stretching the polypropylene sheet using a tenter frame to produce a physically modified polypropylene capacitor film material having a thickness of approximately 10 μm. A sufficient amount of the polypropylene capacitor film material is collected at a rate of 10 rad / min.
[0056] Experimental Example 1
[0057] In this Experimental Example 1, the polypropylene capacitor film materials provided in Examples 1-4 were subjected to performance tests, including compatibility and water absorption performance analysis, oxidation corrosion resistance analysis, and electrical performance analysis.
[0058] Wherein, the results of compatibility and water absorption performance analysis of the polypropylene capacitor film materials provided in Examples 1-3 are shown in Table 1; As can be seen from Table 1, the polypropylene capacitor film material provided in Example 1 is made after adding 1wt% p-aminobenzoic acid polar filler in a polypropylene base material, and since maleic anhydride grafted polypropylene powder is also added as a compatibilizer, the surface of the polypropylene capacitor film material is smooth, and transparency is good, no odor is generated, no visible volatile gas, and the production process is no significant difference from unmodified BOPP, but the water absorption performance is general; The polypropylene capacitor film material provided in Example 3 is made after adding 10wt% p-aminobenzoic acid polar filler in a polypropylene base material, and has excellent water absorption performance, but due to the large amount of p-aminobenzoic acid polar filler added, the compatibility decreases more, and fine white spots appear on the surface of the polypropylene capacitor film material, and the polypropylene capacitor film material provided in Example 2 is made after adding 5wt% p-aminobenzoic acid polar filler in a polypropylene base material, and the comprehensive properties such as water absorption performance and compatibility are excellent, and the addition cost of the p-aminobenzoic acid polar filler is also reduced, which is an ideal polypropylene capacitor film material.
[0059] Table 1: Compatibility and water absorption performance of polypropylene capacitor film materials provided in Examples 1-3
[0060]
[0061] The process of analyzing oxidation corrosion resistance and electrical properties is as follows:
[0062] First, 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 of which is shown in FIG. Figure 1 As shown, the actual picture is as shown in the instruction manual Figure 2 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.
[0063] Then, 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 3-4 shown; from Figure 4 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 reduces the internal water content 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 557 MV m -1 , and the breakdown strength of the polypropylene capacitor film material provided in Example 2 is increased to 576 MV m -1 .
[0064] 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 physically modified polypropylene capacitor film material, characterized in that: include: Polypropylene, maleic anhydride grafted polypropylene and p-aminobenzoic acid polar fillers.
2. The physically modified polypropylene capacitor film material according to claim 1, characterized in that: Calculated by weight, the composition comprises 80-120 weight parts of polypropylene, 8-12 weight parts of maleic anhydride grafted polypropylene and 1-10 weight parts of p-aminobenzoic acid polar filler.
3. A method for preparing a physically modified polypropylene capacitor film material, characterized in that: A physically modified polypropylene capacitor film material according to any one of claims 1 to 2 can be prepared, and the preparation method comprises the following steps: Step S1, physically blending polypropylene and maleic anhydride grafted polypropylene to prepare a polypropylene substrate; Step S2, physically blending the polypropylene substrate and the p-aminobenzoic acid polar filler to prepare a p-aminobenzoic acid / polypropylene composite material; Step S3: melt-blending the p-aminobenzoic acid / polypropylene composite material to prepare a physically modified polypropylene casting sheet, and simultaneously biaxially stretching the sheet to obtain a physically modified polypropylene capacitor film material.
4. The method for preparing a physically modified polypropylene capacitor film material according to claim 3, characterized in that: In step S1, the physical blending process is: adding polypropylene and maleic anhydride grafted polypropylene into a high-speed mixer, and physically blending them at a speed of 1000-1500 r / min for 5-20 minutes.
5. The method for preparing a physically modified polypropylene capacitor film material according to claim 3, characterized in that: In step S2, the physical blending process is: adding the polypropylene substrate and the p-aminobenzoic acid polar filler into the ball milling jar of the ball mill, and ball milling them at a speed of 300 rpm for 6 to 8 hours for physical blending.
6. The method for preparing a physically modified polypropylene capacitor film material according to claim 3, characterized in that: In step S3, the melt blending process is as follows: adding the p-aminobenzoic acid / polypropylene composite material into a twin-screw extruder, and melt blending at a melt temperature of 210-250° C. and a screw speed of 28 rad / min.
7. A single-sided metallized polypropylene film, characterized in that: Comprising a physically modified polypropylene capacitor film material according to any one of claims 1-2 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 physically modified polypropylene capacitor film material according to any one of claims 1 to 2 in a film capacitor.