A high temperature resistant metallized capacitor film and a method of making the same

Abstract

The application discloses a high-temperature-resistant metalized capacitor film and a preparation method thereof, and belongs to the technical field of thin film or thick film capacitors. The application provides a novel method for preparing a metalized capacitor film, which comprises the following steps: taking 4-vinylbenzocyclobutene as raw material, and combining the raw material with hydrogen bromide after an addition reaction to obtain a substitution product; combining 2-methoxy-4-vinylphenol with the substitution product after demethylation to obtain a polymerization monomer containing a double bond and a cycloalkane structure; polymerizing the polymerization monomer with decafluorobiphenyl and 4-allylphenol to obtain a base film; and plating a metal layer on the base film to obtain the high-temperature-resistant metalized capacitor film. The application has good thermal stability, and solves the technical problem that a thermoplastic base film is deformed or decomposed at high temperature, and is difficult to meet the use requirement.

Description

Technical Field

[0001] This invention relates to the field of thin-film or thick-film capacitor technology, and in particular to a high-temperature resistant metallized capacitor film and its preparation method. Background Technology

[0002] Film capacitors use metal foil as electrodes, which are combined with polymer materials such as polyester and polyolefin, and then wound into a cylindrical shape to form a capacitor.

[0003] Chinese patent CN106653366A discloses a metallized thin-film capacitor structure, including a dielectric film and a vapor-deposited electrode layer covering the dielectric film. The vapor-deposited electrode layer includes a first metal layer and a second metal layer, with the first metal layer located on top of the second metal layer. A thickened region is provided at the overlap between the first and second metal layers, and the width of the thickened region is 35% to 50% of the width of the second metal layer. This invention reduces the ESR value of the core package after winding by vapor-depositing an electrode layer on an electrolyte film and providing a thickened region on the vapor-deposited electrode layer, setting the thickened region to be 35% to 50% of the width of the second metal layer. This reduces the ESR value of the core package after winding without affecting the original metallized film properties.

[0004] Similarly, Chinese patent CN112277347A provides an antioxidant metallized thin film and its preparation apparatus and processing method, including a base film, a first adhesion groove on the top surface of the base film, a second adhesion groove on the bottom surface of the base film, adhesive injected into the first adhesion groove, an antioxidant metal layer vapor-deposited on the top surface of the base film, and an edge left on one side of the antioxidant metal layer; including a machine body, a motor and a feeding box are arranged on the outer wall of the machine body, a roller pressing mechanism, a first roller and a second roller are vertically connected between the inner wall of the machine body, a limit wheel is connected to the inner wall of the machine body near the winding column, and a conveying mechanism is arranged at the bottom of the inner wall of the machine body; S1, base film preparation; S2, antioxidant metal layer vapor deposition; the present invention processes the first adhesion groove and the second adhesion groove on the surface of the base film, so that the antioxidant metal layer can adhere more tightly to the base film; the adhesive injected into the first adhesion groove effectively improves the adhesion rate of the vapor-deposited metal layer on the base film, thereby ensuring a more stable capacitor structure.

[0005] Chinese patent CN103996534A discloses a metallized capacitor film with improved oxidation resistance, comprising a metal plating layer and a top and bottom plastic film respectively located on both sides of the metal plating layer. The metal plating layer is made of zinc and / or aluminum, and the top and bottom plastic film are made of polyolefin. The top plastic film has a bottom contact surface that contacts the metal plating layer, and the bottom plastic film has a top contact surface that contacts the metal plating layer. The bottom and top contact surfaces have the same surface charge density. This invention provides a metallized capacitor film with improved oxidation resistance, reducing the penetration of oxidizing charged particles in the air into the top and bottom plastic film layers, and improving the dielectric properties of the top and bottom plastic film layers, thus reducing the probability of breakdown. The invention also discloses a method for manufacturing the aforementioned metallized capacitor film with improved oxidation resistance.

[0006] Currently, the base film material for metallized capacitor films is mostly thermoplastic polymer, which has the advantages of wide availability and convenient material sourcing. However, thermoplastic materials are difficult to meet the requirements for use in high-temperature environments. In actual use, thermoplastic deformation or decomposition may occur, which will damage the integrity and uniformity of the structure and thus affect the normal use of the metallized capacitor film. Summary of the Invention

[0007] In view of the above-mentioned deficiencies of the prior art, the problem to be solved by the present invention is to provide a metallized capacitor film with high temperature resistance and good mechanical properties and a method for preparing the same.

[0008] This invention uses 4-vinylbenzocyclobutene as a raw material, which undergoes an addition reaction with hydrogen bromide and then combines with 1,2-difluorobenzene to obtain a substituted product. 2-Methoxy-4-vinylphenol is demethylated and then combined with the substituted product to obtain a polymeric monomer containing a double bond and a cycloalkane structure. The polymeric monomer is subsequently polymerized with decafluorobiphenyl and 4-allylphenol to prepare a base film. The base film is then metallized to obtain a high-temperature resistant metallized capacitor film.

[0009] The base film of the high-temperature resistant metallized capacitor film exhibits excellent thermal stability, chemical stability, and mechanical properties. The cross-linked benzocyclobutene group, combined with 2-methoxy-4-vinylphenol, yields a monomer with high reactivity. The four-membered cycloalkane structure can react with itself and double bonds during polymerization to form a cross-linked network, endowing the base film with excellent properties. Due to the introduction of a decafluorobiphenyl structure into the base film and the high bond energy of the base film molecular chain, it exhibits good thermal stability at high temperatures. Compared to existing technologies, the base film has low hygroscopicity, effectively mitigating the decrease in insulation performance caused by moisture absorption; the base film surface has good uniformity, resulting in a tighter bond with the metal layer.

[0010] A method for preparing a high-temperature resistant metallized capacitor film includes the following steps:

[0011] S1. Mix 4-vinylbenzocyclobutene with petroleum ether until homogeneous, and introduce hydrogen bromide gas under closed circulation conditions to carry out an addition reaction. During the reaction, the tail gas is refluxed and then absorbed with water. After the addition reaction is completed, remove the petroleum ether by vacuum distillation to obtain the crude addition product. Wash the crude addition product with sodium carbonate aqueous solution, water, and dry to obtain the addition product for later use.

[0012] S2. Take the addition product, 1,2-difluorobenzene and dimethylacetamide and mix them evenly. Then add the catalyst and potassium carbonate, and continue to mix evenly to carry out the substitution reaction. After the substitution reaction is completed, filter and collect the filtrate. Extract the filtrate with ethyl acetate. Wash the obtained organic phase with saturated brine, dry it, distill it under reduced pressure and recrystallize it with anhydrous ethanol to obtain the substitution product for later use.

[0013] S3. Mix 2-methoxy-4-vinylphenol, triethylsilane and toluene evenly, and then heat to react. After the heating reaction is completed, remove toluene by vacuum distillation. Add ammonium fluoride and anhydrous ethanol to the residue, mix evenly and then treat at room temperature. After treatment, remove anhydrous ethanol by vacuum distillation, extract the residue with ethyl acetate, wash the obtained organic phase with saturated brine, dry, and remove ethyl acetate by vacuum distillation to obtain the chemical intermediate for later use.

[0014] S4. Under anaerobic conditions, the aforementioned chemical intermediate, the aforementioned substitution product, potassium carbonate, and dimethyl sulfoxide are mixed evenly, and then a catalyst is added to carry out the chemical reaction. After the chemical reaction is completed, the filtrate is collected by filtration, and the filtrate is extracted with ethyl acetate. The resulting organic phase is washed with saturated brine, dried, and the ethyl acetate is removed by vacuum distillation to obtain the chemical product for later use.

[0015] S5. Take the aforementioned compound product, decafluorobiphenyl, 4-allylphenol and mesitylene and mix them evenly to obtain a polymerization reaction solution; add a catalyst to the polymerization reaction solution and heat and solidify it under anaerobic conditions to obtain a base film for later use;

[0016] S6. A metal layer is deposited on the base film using a vacuum coating equipment to obtain a high-temperature resistant metallized capacitor film.

[0017] Specifically, a method for preparing a high-temperature resistant metallized capacitor film includes the following steps, in parts by weight:

[0018] S1. Mix 1.70-2.20 parts of 4-vinylbenzocyclobutene with 10-25 parts of petroleum ether until homogeneous. Under closed-loop conditions, introduce hydrogen bromide gas to carry out an addition reaction. During the reaction, the tail gas is refluxed and then absorbed by water. After the addition reaction is completed, remove the petroleum ether by vacuum distillation to obtain the crude addition product. Wash the crude addition product with a 15wt% sodium carbonate aqueous solution, wash with water, and dry to obtain the addition product for later use.

[0019] S2. Take 8.20–10.65 parts of the addition product, 6.60–8.60 parts of 1,2-difluorobenzene, and 25–35 parts of dimethylacetamide and mix them evenly. Then add 0.40–0.55 parts of palladium acetate, 1.15–1.45 parts of tri-tert-butylphosphine tetrafluoroborate, and 5.90–7.70 parts of potassium carbonate. After mixing evenly, carry out the substitution reaction. After the substitution reaction is completed, filter and collect the filtrate. Extract the filtrate with ethyl acetate. Wash the obtained organic phase with saturated brine, dry it, distill it under reduced pressure, and recrystallize it with anhydrous ethanol to obtain the substituted product for later use.

[0020] S3. Mix 5.50–7.15 parts of 2-methoxy-4-vinylphenol, 10.50–13.65 parts of triethylsilane, and 50–70 parts of toluene until homogeneous, and then heat the mixture to react. After the heating reaction is complete, remove the toluene by vacuum distillation. Add 1.60–2.15 parts of ammonium fluoride and 60–80 parts of anhydrous ethanol to the residue, mix thoroughly, and then treat at room temperature. After treatment, remove the anhydrous ethanol by vacuum distillation, extract the residue with ethyl acetate, wash the obtained organic phase with saturated brine, dry it, and remove the ethyl acetate by vacuum distillation to obtain the chemical intermediate for later use.

[0021] S4. Under nitrogen protection, 1.75–2.35 parts of the aforementioned chemical intermediate, 2.75–3.60 parts of the aforementioned substituted product, 3.0–4.0 parts of potassium carbonate, and 90–120 parts of dimethyl sulfoxide were mixed evenly. Then, 0.02–0.03 parts of triethylbenzylammonium chloride were added to carry out the chemical reaction. After the chemical reaction was completed, the filtrate was collected by filtration, and the filtrate was extracted with ethyl acetate. The resulting organic phase was washed with saturated brine, dried, and the ethyl acetate was removed by vacuum distillation to obtain the chemical product for later use.

[0022] S5. Take 3.80-4.90 parts of the compound product, 0.85-1.10 parts of decafluorobiphenyl, 0.65-0.90 parts of 4-allylphenol, and 50-75 parts of mesitylene and mix them evenly to obtain a polymerization reaction solution; add 0.04-0.06 parts of cesium fluoride to the polymerization reaction solution, and heat and solidify under nitrogen protection to obtain a base film for later use;

[0023] S6. A metal layer is deposited on the base film using a vacuum coating equipment to obtain a high-temperature resistant metallized capacitor film.

[0024] Preferably, the temperature of the addition reaction in step S1 is 60-75°C and the reaction time is 2-6 hours.

[0025] Preferably, the temperature of the substitution reaction in step S2 is 115–130°C, and the reaction time is 4–12 h.

[0026] Preferably, the heating reaction temperature in step S3 is 90–115°C, and the reaction time is 5–15 min.

[0027] Preferably, the processing time at room temperature in step S3 is 1.5 to 4 hours.

[0028] Preferably, the temperature of the chemical reaction in step S4 is 55–70°C, and the reaction time is 9–18 h.

[0029] Preferably, the heating and curing in step S5 is carried out in two steps: the polymerization reaction liquid is first heated to 195-220°C and reacted for 12-18 hours; then the temperature is raised to 240-255°C and reacted for 0.5-2 hours.

[0030] Preferably, the thickness of the base film is 2-6 μm, and the thickness of the high-temperature resistant metallized capacitor film is 3-9 μm.

[0031] The metal layer deposited on the base film is achieved by evaporation or sputtering, or by other methods commonly used in the art.

[0032] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0033] The descriptions and functions of some of the raw materials in the formula of this invention are as follows:

[0034] 1,2-Difluorobenzene: also known as ortho-difluorobenzene, an organic compound with the chemical formula C6H4F2.

[0035] 2-Methoxy-4-vinylphenol: An organic compound with the molecular formula C9H10H2O. 10 O2.

[0036] Decafluorobiphenyl: an organic compound with the molecular formula C 12 F 10 .

[0037] The beneficial effects of this invention are:

[0038] Compared with existing technologies, this invention provides a novel method for preparing metallized capacitor films. The invention uses 4-vinylbenzocyclobutene as a raw material, which undergoes an addition reaction with hydrogen bromide and then combines with 1,2-difluorobenzene to obtain a substituted product. 2-Methoxy-4-vinylphenol is demethylated and then combined with the substituted product to obtain a polymeric monomer containing double bonds and a cycloalkane structure. The polymeric monomer is subsequently polymerized with decafluorobiphenyl and 4-allylphenol to obtain a base film. The base film is then metallized to obtain a high-temperature resistant metallized capacitor film.

[0039] Compared to existing technologies, the base film of the high-temperature resistant metallized capacitor film exhibits superior thermal stability, chemical stability, and mechanical properties. The cross-linked benzocyclobutene group, combined with 2-methoxy-4-vinylphenol, yields a monomer with high reactivity. The four-membered cycloalkane structure can react with itself and double bonds during polymerization, forming a cross-linked network that endows the base film with excellent properties. Due to the introduction of the decafluorobiphenyl structure into the base film and the high bond energy of the base film molecular chain, it exhibits good thermal stability at high temperatures. The base film has low hygroscopicity, effectively mitigating the decrease in insulation performance caused by moisture absorption; the good surface uniformity of the base film leads to a tighter bond with the metal layer. Detailed Implementation

[0040] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0041] The following are some raw material parameters in the comparative examples and embodiments of the present invention:

[0042] Polypropylene, grade: R370Y, provided by Dongguan Jinkai Plastic Raw Materials Co., Ltd.

[0043] Polycarbonate, grade: 141R-111, provided by Shanghai Xingxiang Plastics Co., Ltd.

[0044] Example 1

[0045] A high-temperature resistant metallized capacitor film is prepared by the following method:

[0046] S1. Mix 1.70 kg of 4-vinylbenzocyclobutene with 10 kg of petroleum ether until homogeneous. Under closed-loop conditions, introduce hydrogen bromide gas to carry out an addition reaction at 70 °C for 4 h. During the reaction, the tail gas is refluxed and then absorbed with water. After the addition reaction is complete, remove the petroleum ether by vacuum distillation to obtain the crude addition product. Wash the crude addition product with a 15 wt% sodium carbonate aqueous solution, rinse with water, and dry to obtain the addition product for later use.

[0047] S2. Take 8.20 kg of the addition product, 6.60 kg of 1,2-difluorobenzene, and 25 kg of dimethylacetamide and mix them evenly. Then add 0.40 kg of palladium acetate, 1.15 kg of tri-tert-butylphosphine tetrafluoroborate, and 5.90 kg of potassium carbonate. After mixing evenly, carry out the substitution reaction at 120°C for 8 hours. After the substitution reaction is completed, filter and collect the filtrate. Extract the filtrate with ethyl acetate. Wash the obtained organic phase with saturated brine, dry it, distill it under reduced pressure, and recrystallize it with anhydrous ethanol to obtain the substituted product for later use.

[0048] S3. Mix 5.50 kg of 2-methoxy-4-vinylphenol, 10.50 kg of triethylsilane, and 50 kg of toluene until homogeneous, then heat the mixture to 105 °C for 10 min. After the reaction is complete, remove the toluene by vacuum distillation. Add 1.60 kg of ammonium fluoride and 60 kg of anhydrous ethanol to the residue, mix thoroughly, and treat at room temperature for 2.5 h. After treatment, remove the anhydrous ethanol by vacuum distillation, extract the residue with ethyl acetate, wash the resulting organic phase with saturated brine, dry, and remove the ethyl acetate by vacuum distillation to obtain the chemical intermediate for later use.

[0049] S4. Under nitrogen protection, 1.75 kg of the aforementioned chemical intermediate, 2.75 kg of the aforementioned substituted product, 3.0 kg of potassium carbonate, and 90 kg of dimethyl sulfoxide were mixed evenly. Then, 0.02 kg of triethylbenzylammonium chloride was added to carry out the chemical reaction. The reaction temperature was 65℃ and the reaction time was 12 h. After the chemical reaction was completed, the filtrate was collected by filtration. The filtrate was extracted with ethyl acetate. The obtained organic phase was washed with saturated brine, dried, and the ethyl acetate was removed by vacuum distillation to obtain the chemical product for later use.

[0050] S5. Take another 3.80 kg of the compound product, 0.85 kg of decafluorobiphenyl, 0.65 kg of 4-allylphenol and 50 kg of mesitylene and mix them evenly to obtain a polymerization reaction solution; add 0.04 kg of cesium fluoride to the polymerization reaction solution, and heat and solidify it in two steps under nitrogen protection. First, heat to 205°C and react for 15 h; then raise the temperature to 245°C and react for 1 h to obtain a base film with a thickness of 4 μm for later use.

[0051] S6. An aluminum layer is deposited on the base film using a vacuum coating equipment by evaporation coating method to obtain a high-temperature resistant metallized capacitor film with a thickness of 6μm.

[0052] Example 2

[0053] A high-temperature resistant metallized capacitor film is prepared by the following method:

[0054] S1. Mix 1.70 kg of 4-vinylbenzocyclobutene with 10 kg of petroleum ether until homogeneous. Under closed-loop conditions, introduce hydrogen bromide gas to carry out an addition reaction at 70 °C for 4 h. During the reaction, the tail gas is refluxed and then absorbed with water. After the addition reaction is complete, remove the petroleum ether by vacuum distillation to obtain the crude addition product. Wash the crude addition product with a 15 wt% sodium carbonate aqueous solution, rinse with water, and dry to obtain the addition product for later use.

[0055] S2. Take 8.20 kg of the addition product, 6.60 kg of 1,2-difluorobenzene, and 25 kg of dimethylacetamide and mix them evenly. Then add 0.40 kg of palladium acetate, 1.15 kg of tri-tert-butylphosphine tetrafluoroborate, and 5.90 kg of potassium carbonate. After mixing evenly, carry out the substitution reaction at 120°C for 8 hours. After the substitution reaction is completed, filter and collect the filtrate. Extract the filtrate with ethyl acetate. Wash the obtained organic phase with saturated brine, dry it, distill it under reduced pressure, and recrystallize it with anhydrous ethanol to obtain the substituted product for later use.

[0056] S3. Mix 5.50 kg of 2-methoxy-4-vinylphenol, 10.50 kg of triethylsilane, and 50 kg of toluene until homogeneous, then heat the mixture to 105 °C for 10 min. After the reaction is complete, remove the toluene by vacuum distillation. Add 1.60 kg of ammonium fluoride and 60 kg of anhydrous ethanol to the residue, mix thoroughly, and treat at room temperature for 2.5 h. After treatment, remove the anhydrous ethanol by vacuum distillation, extract the residue with ethyl acetate, wash the resulting organic phase with saturated brine, dry, and remove the ethyl acetate by vacuum distillation to obtain the chemical intermediate for later use.

[0057] S4. Under nitrogen protection, 1.75 kg of the aforementioned chemical intermediate, 2.75 kg of the aforementioned substituted product, 3.0 kg of potassium carbonate, and 90 kg of dimethyl sulfoxide were mixed evenly. Then, 0.02 kg of triethylbenzylammonium chloride was added to carry out the chemical reaction. The reaction temperature was 65℃ and the reaction time was 12 h. After the chemical reaction was completed, the filtrate was collected by filtration. The filtrate was extracted with ethyl acetate. The obtained organic phase was washed with saturated brine, dried, and the ethyl acetate was removed by vacuum distillation to obtain the chemical product for later use.

[0058] S5. Take another 5.30 kg of the compound product and mix it evenly with 50 kg of mesitylene to obtain a polymerization reaction solution; heat and solidify it in two steps under nitrogen protection. First, heat it to 205°C and react for 15 h; then raise the temperature to 245°C and react for 1 h to obtain a base film for later use. The thickness of the base film is 4 μm.

[0059] S6. An aluminum layer is deposited on the base film using a vacuum coating equipment by evaporation coating method to obtain a high-temperature resistant metallized capacitor film with a thickness of 6μm.

[0060] Example 3

[0061] A high-temperature resistant metallized capacitor film is prepared by the following method:

[0062] S1. Mix 2.20 kg of 4-vinylbenzocyclobutene with 25 kg of petroleum ether until homogeneous. Under closed-loop conditions, introduce hydrogen bromide gas to carry out an addition reaction. The temperature of the addition reaction is 70 °C and the reaction time is 4 h. During the reaction, the tail gas is refluxed and then absorbed with water. After the addition reaction is completed, remove the petroleum ether by vacuum distillation to obtain the crude addition product. Wash the crude addition product with a 15 wt% sodium carbonate aqueous solution, wash with water, and dry to obtain the addition product for later use.

[0063] S2. Take 10.65 kg of the addition product, 8.60 kg of 1,2-difluorobenzene, and 35 kg of dimethylacetamide and mix them evenly. Then add 0.55 kg of palladium acetate, 1.45 kg of tri-tert-butylphosphine tetrafluoroborate, and 7.70 kg of potassium carbonate. After mixing evenly, carry out the substitution reaction at 120°C for 8 hours. After the substitution reaction is completed, filter and collect the filtrate. Extract the filtrate with ethyl acetate. Wash the obtained organic phase with saturated brine, dry it, distill it under reduced pressure, and recrystallize it with anhydrous ethanol to obtain the substituted product for later use.

[0064] S3. Mix 7.15 kg of 2-methoxy-4-vinylphenol, 13.65 kg of triethylsilane, and 70 kg of toluene until homogeneous, then heat the mixture to 105 °C for 10 min. After the reaction, remove the toluene by vacuum distillation. Add 2.15 kg of ammonium fluoride and 80 kg of anhydrous ethanol to the residue, mix thoroughly, and treat at room temperature for 2.5 h. After treatment, remove the anhydrous ethanol by vacuum distillation, extract the residue with ethyl acetate, wash the resulting organic phase with saturated brine, dry, and remove the ethyl acetate by vacuum distillation to obtain the chemical intermediate for later use.

[0065] S4. Under nitrogen protection, 2.35 kg of the aforementioned chemical intermediate, 3.60 kg of the aforementioned substituted product, 4.0 kg of potassium carbonate, and 120 kg of dimethyl sulfoxide were mixed evenly. Then, 0.03 kg of triethylbenzylammonium chloride was added to carry out the chemical reaction. The reaction temperature was 65℃ and the reaction time was 12 h. After the chemical reaction was completed, the filtrate was collected by filtration. The filtrate was extracted with ethyl acetate. The obtained organic phase was washed with saturated brine, dried, and the ethyl acetate was removed by vacuum distillation to obtain the chemical product for later use.

[0066] S5. Take 4.90 kg of the compound product, 1.10 kg of decafluorobiphenyl, 0.90 kg of 4-allylphenol, and 75 kg of mesitylene and mix them evenly to obtain a polymerization reaction solution; add 0.06 kg of cesium fluoride to the polymerization reaction solution, and heat and solidify it in two steps under nitrogen protection. First, heat to 205°C and react for 15 h; then raise the temperature to 245°C and react for 1 h to obtain a base film with a thickness of 4 μm for later use.

[0067] S6. An aluminum layer is deposited on the base film using a vacuum coating equipment by evaporation coating method to obtain a high-temperature resistant metallized capacitor film with a thickness of 6μm.

[0068] Compare with Example 1

[0069] In this comparative example, the base film of the metallized capacitor film is a polypropylene film produced by injection molding and pressing using conventional processes, and the thickness of the base film is 4μm. Using the same evaporation deposition method as in the examples, an aluminum layer is deposited on the polypropylene film using a vacuum deposition equipment to obtain a metallized capacitor film with a thickness of 6μm.

[0070] Compare with Example 2

[0071] In this comparative example, the base film of the metallized capacitor film is a polycarbonate film produced by injection molding and pressing using conventional processes, and the thickness of the base film is 4μm. Using the same evaporation deposition method as in the examples, an aluminum layer is deposited on the polycarbonate film using a vacuum deposition equipment to obtain a metallized capacitor film with a thickness of 6μm.

[0072] Test Example 1

[0073] The thermal stability of the base film in high-temperature metallized capacitor films was tested according to the specific methods and procedures in standard SN / T 3078.2-2015 "Determination of Thermal Stability of Chemicals Part 2: Thermogravimetric Analysis". The tests were conducted under a nitrogen atmosphere with a purge rate of 25 mL / min and a heating rate of 10 °C / min, covering a temperature range from room temperature to 600 °C. The thermal stability of the high-temperature metallized capacitor film base film was characterized by its 5% thermogravimetric temperature and glass transition temperature. The test results are shown in Table 1.

[0074] Table 1:

[0075] project 5% thermogravimetric temperature (°C) Glass transition temperature (°C) Example 1 491 347 Example 2 439 311

[0076] As can be seen from the test results in Table 1, the polymerization of monomers with decafluorobiphenyl and 4-allylphenol in Example 1 has better thermal stability than the self-polymerization of monomers in Example 2.

[0077] Test Example 2

[0078] The mechanical properties of the base film materials in the examples and control examples were tested according to the methods and procedures in standard GB / T 1040.2-2006 "Determination of tensile properties of plastics - Part 2: Test conditions for molded and extruded plastics". The base film materials were prepared into specimens meeting the above standard; the specimens were type 1A. Testing was conducted using an electronic energy testing machine (WDW-GD type, provided by Jinan Xinshijin Testing Machine Co., Ltd.) at a speed of 1 mm / min. Five specimens were tested for each example, and the results were taken as the arithmetic mean. The tensile property test results of the base film materials are shown in Table 2.

[0079] Table 2:

[0080] project Tensile strength (MPa) Example 1 74.5 Example 2 69.0 Compare with Example 1 33.7 Compare with Example 2 65.2

[0081] As can be seen from the test results in Table 2, Examples 1 and 2 have better tensile strength than the base film materials used in the prior art.

[0082] The test results from the above examples show that the base film material used in this invention outperforms existing technologies in both thermal stability and tensile properties. This is likely because this invention uses 4-vinylbenzocyclobutene as a raw material, which undergoes an addition reaction with hydrogen bromide and then combines with 1,2-difluorobenzene to obtain a substituted product. 2-Methoxy-4-vinylphenol is demethylated and then combined with the substituted product to obtain a polymeric monomer containing double bonds and a cycloalkane structure. This monomer is subsequently polymerized with decafluorobiphenyl and 4-allylphenol to obtain a high-performance base film. Compared with the thermoplastic materials used in existing technologies, the base film of the high-temperature resistant metallized capacitor film exhibits excellent thermal stability, chemical stability, and mechanical properties. The cross-linked benzocyclobutene groups, combined with 2-methoxy-4-vinylphenol, result in a monomer with high reactivity. The four-membered cycloalkane structure can react with itself and the double bonds during polymerization to form a cross-linked network, endowing the base film with excellent properties. Due to the introduction of a decafluorobiphenyl structure into the base film and the high bond energy of the base film molecular chain, it exhibits good thermal stability at high temperatures. Compared with existing technologies, the base film has low hygroscopicity, effectively mitigating the decrease in insulation performance caused by moisture absorption; the base film surface has good uniformity, resulting in a tighter bond with the metal layer.

Claims

1. A method for preparing a high-temperature resistant metallized capacitor film, characterized in that, Includes the following steps: S1. Mix 4-vinylbenzocyclobutene with petroleum ether until homogeneous, and introduce hydrogen bromide gas under closed circulation conditions to carry out an addition reaction. During the reaction, the tail gas is refluxed and then absorbed with water. After the addition reaction is completed, remove the petroleum ether by vacuum distillation to obtain the crude addition product. Wash the crude addition product with sodium carbonate aqueous solution, water, and dry to obtain the addition product for later use. S2. Take the addition product, 1,2-difluorobenzene and dimethylacetamide and mix them evenly. Then add the catalyst and potassium carbonate, and continue to mix evenly to carry out the substitution reaction. After the substitution reaction is completed, filter and collect the filtrate. Extract the filtrate with ethyl acetate. Wash the obtained organic phase with saturated brine, dry it, distill it under reduced pressure and recrystallize it with anhydrous ethanol to obtain the substitution product for later use. S3. Mix 5.50-7.15 parts of 2-methoxy-4-vinylphenol, 10.50-13.65 parts of triethylsilane, and 50-70 parts of toluene until homogeneous, then heat the mixture. After the heating reaction, remove the toluene by vacuum distillation. Add 1.60-2.15 parts of ammonium fluoride and 60-80 parts of anhydrous ethanol to the residue, mix thoroughly, and then treat at room temperature. After treatment, remove the anhydrous ethanol by vacuum distillation, extract the residue with ethyl acetate, wash the obtained organic phase with saturated brine, dry, and remove the ethyl acetate by vacuum distillation to obtain a chemical intermediate for later use. The heating reaction temperature is 90-115℃, and the reaction time is 5-15 min. The treatment time at room temperature is 1.5-4 h. S4. Under anaerobic conditions, the aforementioned chemical intermediate, the aforementioned substitution product, potassium carbonate, and dimethyl sulfoxide are mixed evenly, and then a catalyst is added to carry out the chemical reaction. After the chemical reaction is completed, the filtrate is collected by filtration, and the filtrate is extracted with ethyl acetate. The resulting organic phase is washed with saturated brine, dried, and the ethyl acetate is removed by vacuum distillation to obtain the chemical product for later use. S5. Take the aforementioned compound product, decafluorobiphenyl, 4-allylphenol and mesitylene and mix them evenly to obtain a polymerization reaction solution; add a catalyst to the polymerization reaction solution and heat and solidify it under anaerobic conditions to obtain a base film for later use; S6. A metal layer is deposited on the base film using a vacuum coating equipment to obtain a high-temperature resistant metallized capacitor film.

2. The method for preparing a high-temperature resistant metallized capacitor film according to claim 1, characterized in that, The steps include the following, in parts by weight: S1. Mix 1.70-2.20 parts of 4-vinylbenzocyclobutene with 10-25 parts of petroleum ether until homogeneous. Under closed-loop conditions, introduce hydrogen bromide gas to carry out an addition reaction. During the reaction, the tail gas is refluxed and then absorbed by water. After the addition reaction is completed, remove the petroleum ether by vacuum distillation to obtain the crude addition product. Wash the crude addition product with a 15wt% sodium carbonate aqueous solution, wash with water, and dry to obtain the addition product for later use. S2. Take 8.20-10.65 parts of the addition product, 6.60-8.60 parts of 1,2-difluorobenzene, and 25-35 parts of dimethylacetamide and mix them evenly. Then add 0.40-0.55 parts of palladium acetate, 1.15-1.45 parts of tri-tert-butylphosphine tetrafluoroborate, and 5.90-7.70 parts of potassium carbonate. After mixing evenly, carry out the substitution reaction. After the substitution reaction is completed, filter and collect the filtrate. Extract the filtrate with ethyl acetate. Wash the obtained organic phase with saturated brine, dry it, distill it under reduced pressure, and recrystallize it with anhydrous ethanol to obtain the substituted product for later use. S3. Mix 5.50-7.15 parts of 2-methoxy-4-vinylphenol, 10.50-13.65 parts of triethylsilane, and 50-70 parts of toluene until homogeneous, and then heat the mixture to react. After the heating reaction is complete, remove the toluene by vacuum distillation. Add 1.60-2.15 parts of ammonium fluoride and 60-80 parts of anhydrous ethanol to the residue, mix thoroughly, and then treat at room temperature. After treatment, remove the anhydrous ethanol by vacuum distillation, extract the residue with ethyl acetate, wash the obtained organic phase with saturated brine, dry it, and remove the ethyl acetate by vacuum distillation to obtain the chemical intermediate for later use. S4. Under nitrogen protection, 1.75-2.35 parts of the aforementioned chemical intermediate, 2.75-3.60 parts of the aforementioned substituted product, 3.0-4.0 parts of potassium carbonate, and 90-120 parts of dimethyl sulfoxide were mixed evenly. Then, 0.02-0.03 parts of triethylbenzylammonium chloride were added to carry out the chemical reaction. After the chemical reaction was completed, the filtrate was collected by filtration, and the filtrate was extracted with ethyl acetate. The obtained organic phase was washed with saturated brine, dried, and the ethyl acetate was removed by vacuum distillation to obtain the chemical product for later use. S5. Take 3.80-4.90 parts of the compound product, 0.85-1.10 parts of decafluorobiphenyl, 0.65-0.90 parts of 4-allylphenol, and 50-75 parts of mesitylene and mix them evenly to obtain a polymerization reaction solution; add 0.04-0.06 parts of cesium fluoride to the polymerization reaction solution, and heat and solidify under nitrogen protection to obtain a base film for later use; S6. A metal layer is deposited on the base film using a vacuum coating equipment to obtain a high-temperature resistant metallized capacitor film.

3. The method for preparing a high-temperature resistant metallized capacitor film according to claim 2, characterized in that: The addition reaction in step S1 is carried out at a temperature of 60-75°C for 2-6 hours.

4. The method for preparing a high-temperature resistant metallized capacitor film according to claim 2, characterized in that: The temperature of the substitution reaction in step S2 is 115~130℃, and the reaction time is 4~12h.

5. The method for preparing a high-temperature resistant metallized capacitor film according to claim 2, characterized in that: The heating reaction in step S3 is carried out at a temperature of 90~115℃ for 5~15 min; the treatment time at room temperature in step S3 is 1.5~4 h.

6. The method for preparing a high-temperature resistant metallized capacitor film according to claim 2, characterized in that: The temperature of the combination reaction in step S4 is 55~70℃, and the reaction time is 9~18h.

7. The method for preparing a high-temperature resistant metallized capacitor film according to claim 2, characterized in that: The heating and curing described in step S5 is carried out in two steps: the polymerization reaction solution is first heated to 195~220℃ and reacted for 12~18h; then the temperature is raised to 240~255℃ and reacted for 0.5~2h.

8. The method for preparing a high-temperature resistant metallized capacitor film according to claim 1 or 2, characterized in that: The thickness of the base film is 2~6μm, and the thickness of the high-temperature resistant metallized capacitor film is 3~9μm.

9. The method for preparing a high-temperature resistant metallized capacitor film according to claim 1 or 2, characterized in that: The metal layer deposited on the base film is achieved by evaporation deposition or sputtering deposition.

10. A high-temperature resistant metallized capacitor film, characterized in that: It is prepared by the method described in any one of claims 1 to 9.