Polypropylene capacitor film material with high dielectric property, preparation method and capacitor

Abstract

The invention provides a polypropylene capacitor film material with high dielectric property, a preparation method and a capacitor, the film material uses polypropylene as a matrix, nano zirconia with high dielectric constant as a heat conducting filler, and polypropylene wax emulsion as a compatilizer, and uses a coating modification method to reduce the agglomeration phenomenon of nano zirconia, so that the film material has high dielectric property. According to the present invention, with the material, the dispersion in the matrix is more uniform, such that the dielectric property is improved, and the film capacitor prepared from the material can meet the market requirement; the preparation method is simple and convenient, and the polypropylene-based composite material obtained by the method has the advantages of safety, stability, simplicity in operation, low production cost, good mechanical property and dielectric property and the like, is suitable for large-scale production, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material preparation, and in particular to a high-dielectric-performance polypropylene capacitor film material, a preparation method, and a capacitor. Background Art

[0002] Capacitors are one of the three most important basic components in circuits, playing important roles in energy storage, filtering, phase modulation, and coupling. In terms of capacitor classification, there are mainly ceramic capacitors, electrolytic capacitors, and film capacitors. Film capacitors have become an important category of capacitors due to their advantages such as large current carrying capacity and low dielectric loss. Currently, the most widely used film capacitor is polypropylene film capacitor. The core material of this type of capacitor is polypropylene film, and all the polypropylene particles used must be imported. Electrical grade polypropylene particles are different from food grade and packaging grade polypropylene particles. They require extremely high purity, good temperature resistance and electrical insulation strength. However, there is still a significant gap between my country's polypropylene particles and foreign polypropylene particles in terms of isotacticity, ash impurities, etc. In order to avoid a similar supply shortage phenomenon in the capacitor industry as in the case of chips, in recent years a domestic company has jointly studied the localization of polypropylene particles with domestic research institutions, universities, and state-owned enterprises, hoping to break the foreign monopoly of electrical grade polypropylene particles and fill the gap in the localization of polypropylene particles.

[0003] Currently, the materials used to make polypropylene film capacitors have deficiencies in temperature resistance and electrical insulation strength. There are also significant gaps in isotacticity, ash content, and impurities compared to foreign polypropylene particles. Therefore, new technologies are needed to develop a material that can address the dielectric and mechanical performance issues of polypropylene particles. Summary of the Invention

[0004] In view of this, the present invention provides a high dielectric performance polypropylene capacitor film material, comprising the following components in parts by weight:

[0005] Base material, 70-100 parts; thermal conductive filler, 0-30 parts; compatibilizer, 0-1 part; the base material is polypropylene, the thermal conductive filler is nano-zirconium oxide, and the compatibilizer is polypropylene wax emulsion.

[0006] Furthermore, the polypropylene is high dielectric performance polypropylene, its model is HC300BF, and its dielectric constant is 2.2.

[0007] Furthermore, the nano-zirconia particle size is ≤100 nm. Specifically, nano-zirconia exhibits high dielectric properties, primarily manifested in a high dielectric constant and low dielectric loss. Zirconia's dielectric constant is typically between 20 and 30, making it valuable for applications in electronic devices. Furthermore, zirconia maintains stable dielectric properties even at high temperatures, giving it a unique advantage in high-temperature electronic devices.

[0008] Furthermore, the polypropylene wax emulsion has a solids content of 40%. Specifically, the polypropylene wax emulsion has high gloss, excellent film-forming properties and adhesion, and is stable in hard water. By forming a uniform film on the surface of an object, it effectively isolates external pollutants, extends the life of the substrate, and maintains the gloss effect.

[0009] The present invention provides a high-dielectric polypropylene capacitor film material having the following advantages: using high-dielectric polypropylene as a matrix and nano-zirconia as a thermally conductive filler, which itself has a high dielectric constant, and using a polypropylene wax emulsion as a compatibilizer. A coating modification method is employed to reduce the agglomeration of the nano-zirconia, allowing it to be more evenly dispersed within the matrix, thereby improving its dielectric properties and the crystallization temperature of the material. The high-dielectric polypropylene capacitor film material obtained by the present invention has good mechanical properties even when a large filler loading is used, has good safety and stability, low production cost, is suitable for large-scale production, and has broad application prospects.

[0010] A second aspect of the present invention provides a film capacitor made from any of the high-dielectric-performance polypropylene capacitor film materials described above. The materials used in such polypropylene film capacitors meet the material specifications required for film capacitors. The film capacitor has high insulation resistance, a relatively low dissipation factor, and excellent performance at high frequencies. It also has good temperature stability, adapting to varying operating temperatures. It also has high reliability, including a long service life and excellent self-healing properties, capable of self-repairing under overvoltage conditions. The capacitor is small and lightweight, making it easy to install and use. It also has good moisture resistance and anti-interference capabilities, performing well in humid environments and exhibiting strong anti-interference capabilities.

[0011] The third aspect of the present invention further provides a method for preparing a polypropylene capacitor film material with high dielectric properties, comprising:

[0012] Raw material preparation stage: weigh polypropylene and nano zirconium oxide according to the formula, and dry them for later use;

[0013] Material preparation stage: Nano-zirconia and polypropylene wax emulsion are evenly dispersed in a preset ratio, and rotary evaporated. The mixture is dried to obtain modified zirconium oxide, which is then mixed with polypropylene in a certain ratio and melt-blended to be evenly dispersed;

[0014] Composite material hot pressing molding stage: hot pressing the above mixture to obtain a composite material.

[0015] Furthermore, the drying temperature in the raw material preparation stage is 50-90°C.

[0016] Furthermore, the mixture is subjected to vacuum treatment before rotary evaporation.

[0017] Furthermore, the temperature of the melt blending is 170-190° C., and the rotary evaporation time is 6-15 minutes.

[0018] Furthermore, the hot pressing temperature of the hot pressing molding is 180-200° C., the time is 4-15 minutes, and the pressure is 5-20 MPa.

[0019] Specifically, the preparation method has the advantages of safety, stability, simple operation, low production cost, etc., and is suitable for further promotion and use; the film material prepared by this method has good dielectric properties, mechanical properties and thermal stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0021] Figure 1 A flow chart for preparing a high dielectric performance polypropylene capacitor film composite material provided by an embodiment of the present invention;

[0022] Figure 2 A comparison chart of the dielectric constants of the high dielectric performance polypropylene capacitor film composite materials of unmodified nano-zirconia and modified nano-zirconia provided in an embodiment of the present invention, Figure 2-1 It is unmodified nano zirconium oxide. Figure 2-2 It is modified nano zirconium oxide;

[0023] Figure 3 A comparison chart of dielectric loss of unmodified nano-zirconia and modified nano-zirconia high dielectric performance polypropylene capacitor film composite materials provided by an embodiment of the present invention, Figure 3-1 It is unmodified nano zirconium oxide. Figure 3-2 It is modified nano zirconium oxide;

[0024] Figure 4 The embodiment of the present invention provides Figure 4 This is a comparison chart of the crystallization temperature of high dielectric properties polypropylene capacitor film composite materials of unmodified nano-zirconia and modified nano-zirconia. Figure 4-1 It is unmodified nano zirconium oxide. Figure 4-2 It is modified nano zirconium oxide. DETAILED DESCRIPTION

[0025] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, unless there is a conflict, the embodiments of the present disclosure and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] The embodiment of the present invention discloses a polypropylene capacitor film material with high dielectric properties, comprising the following components in parts by weight:

[0027] Base material, 70-100 parts; thermal conductive filler, 0-30 parts; compatibilizer, 0-1 part; the base material is polypropylene, the thermal conductive filler is nano-zirconium oxide, and the compatibilizer is polypropylene wax emulsion.

[0028] In this embodiment, the polypropylene is a polypropylene with high dielectric properties, model HC300BF, and a dielectric constant of 2.2.

[0029] In this embodiment, the particle size of the nano-zirconium oxide is ≤100 nm.

[0030] In this embodiment, the solid content of the polypropylene wax emulsion is 10%-40%.

[0031] In this embodiment, the solid content of the polypropylene wax emulsion is 40%.

[0032] The high-dielectric polypropylene capacitor film material disclosed in this embodiment has the following advantages: It utilizes high-dielectric polypropylene as the matrix and nano-zirconia as the thermally conductive filler, which inherently has a high dielectric constant. A polypropylene wax emulsion is used as a compatibilizer, and a coating modification method is employed to reduce the agglomeration of the nano-zirconia, allowing for a more uniform dispersion within the matrix, thereby improving its dielectric properties and the crystallization temperature of the material. The resulting high-dielectric polypropylene capacitor film material exhibits excellent mechanical properties even with a large filler loading, exhibits good safety and stability, has low production costs, is suitable for large-scale production, and has broad application prospects.

[0033] Another embodiment of the present invention discloses a method for preparing a polypropylene capacitor film material with high dielectric properties, comprising the following steps, referring to Figure 1 As shown:

[0034] SO1, raw material preparation stage: weigh polypropylene and nano zirconium oxide according to the formula, and dry them for later use;

[0035] S02, material preparation stage: Nano-zirconium oxide and polypropylene wax emulsion are ultrasonically vibrated in a beaker in different proportions for 20 minutes. After they are evenly dispersed, the blend is transferred to a rotary evaporator, an appropriate amount of deionized water is added, vacuumized, and rotary evaporated at 80°C and 20rpm. After the solution in the mixture is evaporated to dryness, it is taken out, placed in an oven, and dried to obtain coated modified nano-zirconium oxide. The modified nano-zirconium oxide is then mixed evenly with polypropylene in a certain ratio, and then melt-blended and dispersed in a Harp internal mixer;

[0036] S03, composite material hot pressing molding stage: the above mixture is pressed into shape to obtain a composite material.

[0037] In this embodiment, in step SO1, the drying temperature is 50-90°C.

[0038] In this embodiment, the temperature of the melt blending is 170-190° C., the rotation speed of the rotary evaporation is 50-60 rpm / min, and the time is 6-15 min.

[0039] In this embodiment, the hot pressing temperature of the hot pressing molding is 180-200° C., the time is 4-15 minutes, and the pressure is 5-20 MPa.

[0040] The preparation method disclosed in this embodiment has the advantages of safety, stability, simple operation, low production cost, etc., and is suitable for further promotion and use; the film material prepared by this method has good dielectric properties, mechanical properties and thermal stability.

[0041] The embodiment of the present invention further discloses a film capacitor, which is prepared using the high dielectric performance polypropylene capacitor film material disclosed in the above embodiment.

[0042] The film capacitor disclosed in this embodiment has high insulation resistance and relatively low loss factor, and can maintain excellent performance at high frequencies. It has good temperature stability: good temperature stability and can adapt to different working environment temperatures. It has high reliability: a long service life and good self-healing properties, and can self-repair under overvoltage conditions; the capacitor has the characteristics of small size and light weight, which is easy to install and use; it has good moisture resistance and anti-interference ability: this capacitor performs well in a humid environment and has strong anti-interference ability.

[0043] The present invention will be further explained below with reference to specific examples:

[0044] In the following examples, unless otherwise specified, the raw materials can be purchased from the market, the operating methods used are all conventional operating methods, and the equipment used are all conventional equipment.

[0045] Example 1

[0046] A high dielectric performance polypropylene capacitor film composite material is prepared by the following steps:

[0047] (1) Raw material preparation stage: Weigh a certain amount of polypropylene and nano-zirconia according to the formula, dry the polypropylene and nano-zirconia for later use; the polypropylene model is HC300BF, with a dielectric constant of 2.2. The particle size of the nano-zirconia is 100nm.

[0048] (2) Material preparation stage: 50 g of polypropylene was weighed and melt-blended and dispersed in a Harp internal mixer;

[0049] (3) Composite material compression molding stage: The above mixture is compression molded to obtain a composite material.

[0050] Wherein, the drying temperature in step (1) is 70°C.

[0051] Preferably, the melt blending in step (2) is carried out at a temperature of 180° C., a rotation speed of 55 rpm / min, and a time of 10 min.

[0052] The hot pressing temperature in step (3) is 190° C., the time is 9 minutes, and the pressure is 13 MPa.

[0053] Reference Figure 2-4 As shown, after testing, the dielectric constant of Example 1 is 2.25, the dielectric loss is 0.005, and the crystallization temperature is 109°C.

[0054] Example 2

[0055] A high dielectric performance polypropylene capacitor film composite material is prepared by the following steps:

[0056] (1) Raw material preparation stage: Weigh a certain amount of polypropylene and nano-zirconia according to the formula, dry the polypropylene and nano-zirconia for later use; the polypropylene model is HC300BF, with a dielectric constant of 2.2. The particle size of the nano-zirconia is 100nm.

[0057] (2) Material preparation stage: 5 g of nano-zirconium oxide and 1.39 g of polypropylene wax emulsion were weighed and ultrasonically shaken in a beaker. The mixture was vacuum-evaporated in a rotary evaporator and then dried to obtain modified nano-zirconium oxide. 45 g of polypropylene was weighed and mixed evenly, and then melt-blended and dispersed in a Harp internal mixer;

[0058] (3) Composite material compression molding stage: The above mixture is compression molded to obtain a composite material.

[0059] Wherein, the drying temperature in step (1) is 60°C.

[0060] Wherein, the temperature of the melt blending in step (2) is 170° C., the rotation speed is 50 rpm / min, and the time is 8 min.

[0061] The hot pressing temperature in step (3) is 180° C., the time is 8 min, and the pressure is 10 MPa.

[0062] Reference Figure 2-4 As shown, after testing, the dielectric constant of Example 2 is 2.65, the dielectric loss is 0.032, and the crystallization temperature is 124°C.

[0063] Example 3

[0064] A high dielectric performance polypropylene capacitor film composite material is prepared by the following steps:

[0065] (1) Raw material preparation stage: Weigh a certain amount of polypropylene and nano-zirconia according to the formula, dry the polypropylene and nano-zirconia for later use; the polypropylene model is HC300BF, with a dielectric constant of 2.2. The particle size of the nano-zirconia is 100nm.

[0066] (2) Material preparation stage: 15 g of nano-zirconium oxide and 4.67 g of polypropylene wax emulsion were weighed and ultrasonically shaken in a beaker. The mixture was vacuum-evaporated in a rotary evaporator and then dried to obtain modified nano-zirconium oxide. 35 g of polypropylene was weighed and mixed uniformly, and then melt-blended and dispersed in a Harp internal mixer;

[0067] (3) Composite material compression molding stage: The above mixture is compression molded to obtain a composite material.

[0068] Wherein, the drying temperature in step (1) is 80°C.

[0069] Wherein, the temperature of the melt blending in step (2) is 190° C., the rotation speed is 60 rpm / min, and the time is 12 min.

[0070] The hot pressing temperature in step (3) is 200° C., the time is 10 min, and the pressure is 15 MPa.

[0071] Reference Figure 2-4 As shown, after testing, the dielectric constant of Example 3 is 3.15, the dielectric loss is 0.047, and the crystallization temperature is 126°C.

[0072] Comparative Example 1

[0073] A high dielectric performance polypropylene capacitor film composite material is prepared by the following steps:

[0074] (1) Raw material preparation stage: weigh a certain amount of polypropylene and nano zirconium oxide according to the formula, dry the polypropylene and nano zirconium oxide for later use;

[0075] (2) Material preparation stage: 50 g of polypropylene was weighed and melt-blended and dispersed in a Harp internal mixer;

[0076] (3) Composite material compression molding stage: The above mixture is compression molded to obtain a composite material.

[0077] Wherein, the drying temperature in step (1) is 70°C.

[0078] Wherein, the temperature of the melt blending in step (2) is 180° C., the rotation speed is 55 rpm / min, and the time is 10 min.

[0079] The hot pressing temperature in step (3) is 190° C., the time is 9 minutes, and the pressure is 13 MPa.

[0080] Reference Figure 2-4 As shown, after testing, the dielectric constant of Comparative Example 1 is 2.23, the dielectric loss is 0.005, and the crystallization temperature is 109°C.

[0081] Comparative Example 2

[0082] A high dielectric performance polypropylene capacitor film composite material is prepared by the following steps:

[0083] (1) Raw material preparation stage: weigh a certain amount of raw materials according to the formula, dry the polypropylene and nano zirconium oxide for later use

[0084] (2) Material preparation stage: Weigh 45g of polypropylene and 5g of nano-zirconia and mix them evenly, then melt blend and disperse them in a Harp internal mixer;

[0085] (3) Composite material compression molding stage: The above mixture is compression molded to obtain a composite material.

[0086] Wherein, the drying temperature in step (1) is 60°C.

[0087] Wherein, the temperature of the melt blending in step (2) is 170° C., the rotation speed is 50 rpm / min, and the time is 8 min.

[0088] The hot pressing temperature in step (3) is 180° C., the time is 8 min, and the pressure is 10 MPa.

[0089] Reference Figure 2-4 As shown, after testing, the dielectric constant of Comparative Example 2 is 2.20, the dielectric loss is 0.046, and the crystallization temperature is 116°C.

[0090] Comparative Example 3

[0091] A high dielectric performance polypropylene capacitor film composite material is prepared by the following steps:

[0092] (1) Raw material preparation stage: weigh a certain amount of raw materials according to the formula, dry the polypropylene and nano zirconium oxide for later use;

[0093] (2) Material preparation stage: 35 g of polypropylene and 15 g of nano-zirconia were weighed and mixed evenly, and then melt blended and dispersed in a Harp internal mixer;

[0094] (3) Composite material compression molding stage: The above mixture is compression molded to obtain a composite material.

[0095] Wherein, the drying temperature in step (1) is 80°C.

[0096] Wherein, the temperature of the melt blending in step (2) is 190° C., the rotation speed is 60 rpm / min, and the time is 12 min.

[0097] The hot pressing temperature in step (3) is 200° C., the time is 10 min, and the pressure is 15 MPa.

[0098] Reference Figure 2-4 As shown, after testing, the dielectric constant of Comparative Example 3 is 4.09, the dielectric loss is 0.21, and the crystallization temperature is 119°C.

[0099] Result detection

[0100] The dielectric properties of the polypropylene-based composite materials prepared in Examples 1, 2, 3 and Comparative Examples 1, 2, 3 were tested using a broadband dielectric impedance spectrometer to obtain the dielectric constant and dielectric loss of each sample. The test frequency was 2×10 1 ~2×10 6Hz, tested at room temperature. DSC analysis: Differential scanning calorimetry was used to investigate the melting and crystallization temperatures of the composite material. A 5-10 mg sample was heated from room temperature to 200°C at a heating rate of 15°C / min under a nitrogen atmosphere. The sample was then held at 200°C for 3 minutes to eliminate the thermal history. The sample was then cooled to room temperature at a cooling rate of 15°C / min to obtain a crystallization curve. The sample was then heated from room temperature to 200°C at a heating rate of 10°C / min to obtain a melting curve.

[0101] The above test results show that: nano-zirconia with ultra-high dielectric constant is used as a conductive filler, and polypropylene wax emulsion is used as a coating modification compatibilizer. The coating modification method is used to reduce the agglomeration of nano-zirconia, make it more evenly dispersed in the matrix, and improve the interfacial bonding force between the group and the filler, thereby improving the dielectric properties, mechanical properties and thermal stability of polymer nanocomposites.

[0102] In summary, the high-dielectric-performance polypropylene capacitor film material and method disclosed in the embodiments of the present invention have the following beneficial technical effects: utilizing polypropylene as the matrix, nano-zirconia with a high dielectric constant as the thermally conductive filler, and a polypropylene wax emulsion as the compatibilizer, the coating and modification method reduces nano-zirconia agglomeration and enables a more uniform dispersion within the matrix, thereby improving its dielectric properties. The resulting polypropylene-based composite material has the advantages of safety, stability, simple operation, low production cost, and excellent mechanical properties. It is suitable for large-scale production and has broad application prospects.

[0103] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside", and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0104] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0105] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A high dielectric performance polypropylene capacitor film material, characterized in that: The composition comprises the following components in parts by weight: Base material, 70-100 parts; thermal conductive filler, 0-30 parts; compatibilizer, 0-1 part; the base material is polypropylene, the thermal conductive filler is nano-zirconium oxide, and the compatibilizer is polypropylene wax emulsion.

2. The high dielectric performance polypropylene capacitor film material according to claim 1, characterized in that: The polypropylene is a high dielectric performance polypropylene, the model of which is HC300BF and the dielectric constant is 2.

2.

3. The high dielectric performance polypropylene capacitor film material according to claim 1, characterized in that: The particle size of the nano zirconium oxide is ≤100 nm.

4. The high dielectric performance polypropylene capacitor film material according to claim 1, characterized in that: The solid content of the polypropylene wax emulsion is 10%-40%, preferably 40%.

5. A film capacitor, characterized in that: The polypropylene capacitor film material with high dielectric properties is prepared using the material described in any one of claims 1 to 4.

6. A method for preparing a high dielectric performance polypropylene capacitor film material according to any one of claims 1 to 4, characterized in that: include: Raw material preparation stage: weigh polypropylene and nano zirconium oxide according to the respective proportions of the formula, and dry them for later use; Material preparation stage: Nano-zirconia and polypropylene wax emulsion are evenly dispersed in a preset ratio, and rotary evaporated. The mixture is dried to obtain modified zirconium oxide, which is then mixed with polypropylene in a certain ratio and melt-blended to be evenly dispersed; Composite material hot pressing molding stage: hot pressing the above mixture to obtain a composite material.

7. The method for preparing a high dielectric performance polypropylene capacitor film material according to claim 6, characterized in that: The drying temperature during the raw material preparation stage is 50-90°C.

8. The method for preparing a polypropylene capacitor film material with high dielectric properties according to claim 6, characterized in that: The temperature of the melt blending is 170-190° C., and the rotary evaporation time is 6-15 minutes.

9. The method for preparing a high dielectric performance polypropylene capacitor film material according to claim 6, characterized in that: The mixture was vacuumed before rotary evaporation.

10. The method for preparing a polypropylene capacitor film material with high dielectric properties according to claim 6, characterized in that: The hot pressing temperature of the hot pressing molding is 180-200° C., the time is 4-15 minutes, and the pressure is 5-20 MPa.

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