Moisture- and heat-resistant metallized thin films and their preparation methods

Abstract

This invention discloses a heat- and moisture-resistant metallized thin film and its preparation method, comprising an insulating dielectric layer, a metal layer, and a protective layer. The protective layer comprises a network-like nano-carbon porous layer and a modified oil layer. The modified oil layer comprises the following components by weight: 90-100 parts silicone oil and 0.05-0.2 parts additives. This invention forms microscopic "anchoring sites" on the surface of the network-like nano-carbon porous layer. When the modified oil layer is coated on it, silicone oil molecules and the additives therein can embed into these sites, so that the network-like nano-carbon porous layer and silicone oil molecules are firmly bonded. This allows the oil layer to be uniformly dispersed in the initial coating stage, avoiding large agglomeration. Because some oil in the modified oil penetrates into the pores of the network-like nano-carbon porous layer, the movement range of these oil molecules is restricted, thereby restraining the entire oil layer and effectively avoiding the problems of agglomeration or migration.

Description

Technical Field

[0001] This invention relates to the field of metallized thin film technology, and more particularly to humid heat-resistant metallized thin films and their preparation methods. Background Technology

[0002] Film capacitors are used in home appliances, electric vehicles, and charging equipment to mitigate current surges and filter alternating circuits. The principle involves storing charge in two mutually insulated, opposing thin metal layers. These metal layers are disposed on the surface of a polymer film, which is then wound together to form an alternating stacked structure of metal and polymer layers. Because each layer is very thin, the film capacitor provides a sufficiently large surface area to store charge.

[0003] Oil coating can be used to manufacture moisture-resistant capacitor films. The oil layer requires a small amount and is low in cost, making it a common production method for moisture-resistant capacitor films today. The oil layer covers the surface of the metal layer. Because the oil layer is more hydrophobic than the metal, it can prevent water vapor from directly contacting the metal surface and prevent metal oxidation. However, since the oil layer is a liquid and has the characteristics of agglomeration and transfer, the morphology of the oil layer on the metal layer surface is unstable, and the exposed part of the metal layer is easily corroded by moisture. Therefore, there is an urgent need for moisture-resistant metallized films and their preparation methods to solve this problem. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides the following technical solution:

[0005] A heat- and moisture-resistant metallized film, comprising an insulating dielectric layer, a metal layer, and a protective layer;

[0006] The protective layer comprises a network of nano-carbon porous layers and a modified oil layer, wherein the modified oil layer comprises the following components by weight: 90-100 parts silicone oil and 0.05-0.2 parts additives.

[0007] As an improvement to the above technical solution, the additive includes nano-titanium dioxide, modified nano-silica, and polymethyl methacrylate, wherein the mass ratio of nano-titanium dioxide, modified nano-silica, and polymethyl methacrylate is (1-1.5):(0.5-1):(1-2).

[0008] As an improvement to the above technical solution, the thickness of the insulating dielectric layer is 3μm-8μm, the thickness of the metal layer is 20nm-40nm, and the thickness of the protective layer is 10nm-30nm.

[0009] As an improvement to the above technical solution, the preparation method of the modified nano-silica includes the following steps: the modified nano-silica is surface-treated with a silane coupling agent to obtain modified nano-silica.

[0010] The method for preparing the heat-resistant metallized thin film includes the following steps;

[0011] S1: Slowly add terephthalic acid to methanol solvent and stir to dissolve it, forming a terephthalic acid solution with a concentration of 0.01-0.1 mol / L. Add zinc nitrate to another part of methanol solvent and stir to fully dissolve the zinc nitrate, obtaining a transparent zinc ion solution with a concentration of 0.05-0.2 mol / L.

[0012] S2: 0.01-0.1 g / mL of polyethylene glycol is added to the zinc ion solution and mixed evenly to form a mixed solution. The insulating dielectric layer with the metal layer is immersed in the mixed solution. The terephthalic acid solution is slowly added to the mixed solution. The temperature is 25-35℃ and the reaction time is 1-3 hours. Zinc ions and terephthalic acid molecules will gradually diffuse to the surface of the metal layer and form a continuous MOF layer on the surface of the metal layer.

[0013] S3: The metal thin film with MOF grown is transferred to a high-temperature furnace under an inert atmosphere for carbonization treatment to form a network of nano-carbon porous layers.

[0014] S4: Mix the silicone oil and additives evenly according to the formula to form a modified oil. Spray the modified oil onto the network-like nano-carbon porous layer in several layers until the required thickness of the protective layer is achieved.

[0015] As an improvement to the above technical solution, in step S4, after each spraying, it is necessary to wait 15-20 minutes and perform drying treatment at a temperature of 40-80℃.

[0016] As an improvement to the above technical solution, the heating rate of the high-temperature furnace in step S3 is 1-5℃ / min, and the carbonization temperature is 500℃-800℃.

[0017] The beneficial effects of this invention are:

[0018] The network-like porous nano-carbon layer forms microscopic "anchoring sites" on its surface. When the modified oil layer is applied to it, silicone oil molecules and additives can embed into these sites, allowing the network-like porous nano-carbon layer to bond firmly with the silicone oil molecules. This ensures that the oil layer is evenly dispersed in the initial coating stage, preventing large agglomerations. Because some oil in the modified oil seeps into the pores of the network-like porous nano-carbon layer, the movement range of these oil molecules is restricted, thus restraining the entire oil layer and effectively preventing agglomeration or migration. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the metallized thin film structure of the present invention.

[0020] Reference numerals: 1 Insulating dielectric layer; 2 Metal layer; 3 Protective layer. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] A heat- and moisture-resistant metallized film, comprising an insulating dielectric layer 1, a metal layer 2, and a protective layer 3;

[0023] The protective layer 3 includes a network-like nano-carbon porous layer and a modified oil layer, wherein the modified oil layer includes silicone oil and additives.

[0024] The additives include nano-titanium dioxide, modified nano-silica, and polymethyl methacrylate;

[0025] The thickness of the insulating dielectric layer 1 is 3μm-8μm, the thickness of the metal layer 2 is 20nm-40nm, and the thickness of the protective layer 3 is 10nm-30nm.

[0026] The method for preparing the modified nano-silica includes the following steps: the modified nano-silica is surface-treated with a silane coupling agent to obtain modified nano-silica. Specific Implementation

[0028] Preparation Example 1

[0029] Nano-titanium dioxide, modified nano-silica, and polymethyl methacrylate are mixed in a mass ratio of 1:1:1 to prepare an additive.

[0030] Preparation Example 2

[0031] An additive is prepared by mixing nano-titanium dioxide, modified nano-silica, and polymethyl methacrylate in a mass ratio of 1.1:0.9:1.4.

[0032] Preparation Example 3

[0033] An additive is prepared by mixing nano-titanium dioxide, modified nano-silica, and polymethyl methacrylate in a mass ratio of 1.3:0.7:1.8.

[0034] Preparation Example 4

[0035] An additive is prepared by mixing nano-titanium dioxide, modified nano-silica, and polymethyl methacrylate in a mass ratio of 1.5:0.5:2.

[0036] Example 1

[0037] This embodiment provides a method for preparing a heat- and moisture-resistant metallized thin film, the specific steps of which are as follows:

[0038] S1: Slowly add terephthalic acid to methanol solvent and stir to dissolve it, forming a 0.01 mol / L terephthalic acid solution. Add zinc nitrate to another part of methanol solvent and stir to fully dissolve the zinc nitrate, obtaining a 0.05 mol / L transparent zinc ion solution.

[0039] S2: 0.01 g / mL of polyethylene glycol is added to the zinc ion solution and mixed evenly to form a mixed solution. The insulating dielectric layer with the metal layer is immersed in the mixed solution. The terephthalic acid solution is slowly added to the mixed solution. The temperature is 25℃ and the reaction time is 1 h. Zinc ions and terephthalic acid molecules will gradually diffuse to the surface of the metal layer and form a continuous MOF layer on the surface of the metal layer.

[0040] S3: The metal thin film with MOF grown is transferred to a high-temperature furnace under an inert atmosphere for carbonization treatment to form a network-like nano-carbon porous layer. The heating rate of the high-temperature furnace is 1℃ / min, and the carbonization temperature is 500℃.

[0041] S4: Weigh 90kg of silicone oil and 0.05kg of additive and mix them evenly to form modified oil. Spray the modified oil onto the network-like nano-carbon porous layer in several applications until the required thickness of the protective layer is achieved. After each application, wait 15 minutes and then dry the oil at 40℃.

[0042] Example 2

[0043] This embodiment provides a method for preparing a heat- and moisture-resistant metallized thin film, the specific steps of which are as follows:

[0044] S1: Slowly add terephthalic acid to methanol solvent and stir to dissolve it, forming a 0.05 mol / L terephthalic acid solution. Add zinc nitrate to another part of methanol solvent and stir to fully dissolve the zinc nitrate, obtaining a 0.1 mol / L transparent zinc ion solution.

[0045] S2: 0.05 g / mL of polyethylene glycol is added to the zinc ion solution and mixed evenly to form a mixed solution. The insulating dielectric layer with the metal layer is immersed in the mixed solution. The terephthalic acid solution is slowly added to the mixed solution. The temperature is 30℃ and the reaction time is 2 hours. Zinc ions and terephthalic acid molecules will gradually diffuse to the surface of the metal layer and form a continuous MOF layer on the surface of the metal layer.

[0046] S3: The metal thin film with MOF grown is transferred to a high-temperature furnace under an inert atmosphere for carbonization treatment to form a network-like nano-carbon porous layer. The heating rate of the high-temperature furnace is 3℃ / min, and the carbonization temperature is 600℃.

[0047] S4: Weigh 95kg of silicone oil and 0.1kg of additive and mix them evenly to form modified oil. Spray the modified oil onto the network-like nano-carbon porous layer in several applications until the required thickness of the protective layer is achieved. After each application, wait 18 minutes and dry at 60℃.

[0048] Example 3

[0049] This embodiment provides a method for preparing a heat- and moisture-resistant metallized thin film, the specific steps of which are as follows:

[0050] S1: Slowly add terephthalic acid to methanol solvent and stir to dissolve it, forming a 0.1 mol / L terephthalic acid solution. Add zinc nitrate to another part of methanol solvent and stir to fully dissolve the zinc nitrate, obtaining a 0.2 mol / L transparent zinc ion solution.

[0051] S2: 0.1 g / mL of polyethylene glycol is added to the zinc ion solution and mixed evenly to form a mixed solution. The insulating dielectric layer with the metal layer is immersed in the mixed solution. The terephthalic acid solution is slowly added to the mixed solution. The temperature is 35℃ and the reaction time is 3h. Zinc ions and terephthalic acid molecules will gradually diffuse to the surface of the metal layer and form a continuous MOF layer on the surface of the metal layer.

[0052] S3: The metal thin film with MOF grown is transferred to a high-temperature furnace under an inert atmosphere for carbonization treatment to form a network-like nano-carbon porous layer. The heating rate of the high-temperature furnace is 5℃ / min, and the carbonization temperature is 800℃.

[0053] S4: Weigh 100kg of silicone oil and 0.2kg of additive and mix them evenly to form modified oil. Spray the modified oil onto the network-like nano-carbon porous layer in several applications until the required thickness of the protective layer is achieved. After each application, wait 20 minutes and then dry the oil at 80℃.

[0054] Comparative Example 1

[0055] This comparative example is used to prepare a heat- and moisture-resistant metallized film. The difference between this comparative example and Example 1 is that no additives are added to the modified oil in this comparative example.

[0056] Capacitor damp heat resistance test:

[0057] Using the metallized thin films prepared in Examples 1-3 and Comparative Examples 1-2, capacitors were fabricated. Capacitor 1 was prepared in Example 1, capacitor 2 was prepared in Example 2, and so on, until capacitor 4 was prepared in Comparative Example 1.

[0058] The fabricated capacitors were placed in an environment of 310VAC, 85℃, and 85%RH for 1500 hours. The capacitance before and after treatment was measured, and the rate of change in capacitance was calculated.

[0059] Capacity change rate = (C 1500hr -C 0hr ) / C 0hr ×100%

[0060] In the formula, C 1500hr C 0hr These are the capacitor capacities before and after the damp heat treatment, respectively.

[0061] The test results are shown in the table below.

[0062]

[0063] Table 1

[0064] As shown in Table 1, the capacitors 1-3 assembled using the metallized thin film prepared in this application exhibit a capacitance change rate of less than 20% during a 1500hr damp heat test. The network-like nanoporous structure of nano-carbon has a large specific surface area, and its surface forms microscopic "anchoring sites." When the modified oil layer is coated on it, silicone oil molecules and additives therein can embed into these sites, making the network-like nano-carbon porous layer firmly bonded to the silicone oil molecules. This allows the oil layer to be uniformly dispersed in the initial coating stage, avoiding large agglomeration. Because some oil in the modified oil penetrates into the pores of the network-like nano-carbon porous layer, the movement range of these oil molecules is restricted, thereby restraining the entire oil layer and effectively avoiding the problems of agglomeration or migration.

[0065] In contrast, the capacitor 4 prepared in Comparative Example 1 showed a capacitance change rate of more than 20% during a 1500hr damp heat test. This was because the oil layer formed by silicone oil molecules was not easy to spread, and the metal was partially exposed, resulting in poor damp heat resistance of the metallized film.

[0066] Further analysis of Table 1 reveals that capacitor 2 exhibits superior performance compared to other embodiments. The inventors conducted the following Examples 4-7 to analyze the influence of the mass ratio of titanium dioxide, modified silica, and polymethyl methacrylate on the moisture and heat resistance of the capacitor.

[0067] Example 4

[0068] This embodiment is used to prepare a heat- and moisture-resistant metallized film. The difference from Example 2 is that the additives in this embodiment are those prepared in Preparation Example 1.

[0069] Example 5

[0070] This embodiment is used to prepare a heat- and moisture-resistant metallized film. The difference from Example 2 is that the additives in this embodiment are the same as those prepared in Example 2.

[0071] Example 6

[0072] This embodiment is used to prepare a heat- and moisture-resistant metallized film. The difference from Example 2 is that the additives in this embodiment are the same as those prepared in Preparation Example 3.

[0073] Example 7

[0074] This embodiment is used to prepare a heat- and moisture-resistant metallized film. The difference from Example 2 is that the additives in this embodiment are those prepared in Preparation Example 4.

[0075] Using the metallized thin films prepared in Examples 4-7 above, capacitors were fabricated. Capacitor 5 was prepared in Example 4, and so on, until capacitor 8 was prepared in Example 7.

[0076] The test results are shown in the table below.

[0077]

[0078] Table 2

[0079] Table 2 shows that for capacitors 5-8, the capacitance change rate during the 1500hr damp heat test was less than 10%. In the process of bonding silicone oil with the network-like nano-carbon porous layer, nano-silica, nano-titanium dioxide, and polymethyl methacrylate exhibited a synergistic effect. Nano-titanium dioxide tightly connected to silicone oil molecules through chemical adsorption, and its surface active sites could capture silicone oil molecules, regulating the intermolecular distance of the silicone oil. During heating, this tight connection prevented silicone oil molecules from agglomerating due to excessive thermal motion, ensuring the silicone oil remained effectively bonded to the nano-carbon porous layer. The modified nano-silica spreads evenly on the porous layer in a stable film state, maintaining the uniformity of the oil layer. On the one hand, it can form a strong chemical bond with silicone oil, and on the other hand, it has a certain affinity with the nano-carbon porous layer. It can be partially embedded in the pores of the nano-carbon porous layer, using chemical bonds to "bridge" the nano-carbon porous layer and silicone oil, preventing the silicone oil from shifting or agglomerating due to loosening. The polymethyl methacrylate polymer chain has a certain degree of flexibility. When interacting with the nano-carbon porous layer, its chain segments can wrap around the nanofibers or pore walls of the nano-carbon porous layer. This entanglement provides silicone oil with additional "binding force." When silicone oil is subjected to thermal motion or external force and tends to flow, polymethyl methacrylate (PMMA) restricts the movement range of silicone oil by entanglement with the nano-carbon porous layer and molecular entanglement with silicone oil, maintaining the fixed position of the oil layer on the nano-carbon porous layer. Titanium dioxide, modified silica, and PMMA interact with the nano-carbon porous layer and silicone oil, and from multiple dimensions such as physical adsorption, chemical bonding, and structural entanglement, comprehensively ensure the stable and even distribution of silicone oil on the nano-carbon porous layer, effectively overcoming the problems of agglomeration and migration.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it.

Claims

1. A heat- and moisture-resistant metallized film, characterized in that, It includes an insulating dielectric layer, a metal layer, and a protective layer; The protective layer comprises a network of nano-carbon porous layers and a modified oil layer, wherein the modified oil layer comprises the following components by weight: 90-100 parts silicone oil and 0.05-0.2 parts additives. The additives include nano-titanium dioxide, modified nano-silica, and polymethyl methacrylate, wherein the mass ratio of nano-titanium dioxide, modified nano-silica, and polymethyl methacrylate is (1-1.5):(0.5-1):(1-2). The thickness of the insulating dielectric layer is 3 μm - 8 μm, the thickness of the metal layer is 20 nm - 40 nm, and the thickness of the protective layer is 10 nm - 30 nm. The method for preparing the modified nano-silica includes the following steps: the modified nano-silica is surface-treated with a silane coupling agent to obtain modified nano-silica.

2. A method for preparing a heat-resistant metallized thin film according to claim 1, characterized in that: Includes the following steps; S1: Slowly add terephthalic acid to methanol solvent and stir to dissolve it, forming a terephthalic acid solution with a concentration of 0.01 - 0.1 mol / L. Add zinc nitrate to another part of methanol solvent and stir to fully dissolve the zinc nitrate, obtaining a transparent zinc ion solution with a concentration of 0.05 - 0.2 mol / L. S2: 0.01 - 0.1 g / mL of polyethylene glycol is added to the zinc ion solution and mixed evenly to form a mixed solution. The insulating dielectric layer with the metal layer is immersed in the mixed solution. The terephthalic acid solution is slowly added to the mixed solution. The temperature is 25-35℃ and the reaction time is 1-3h. Zinc ions and terephthalic acid molecules will gradually diffuse to the surface of the metal layer and form a continuous MOF layer on the surface of the metal layer. S3: The metal thin film with MOF grown is transferred to a high-temperature furnace under an inert atmosphere for carbonization treatment to form a network of nano-carbon porous layers. S4: Mix the silicone oil and additives evenly according to the formula to form a modified oil. Spray the modified oil onto the network-like nano-carbon porous layer in several layers until the required thickness of the protective layer is achieved.

3. The method for preparing a heat-resistant metallized thin film according to claim 2, characterized in that: In step S4, after each spraying, it is necessary to wait 15-20 minutes and then perform drying treatment at a temperature of 40-80℃.

4. The method for preparing a heat-resistant metallized thin film according to claim 2, characterized in that: In step S3, the heating rate of the high-temperature furnace is 1-5℃ / min, and the carbonization temperature is 500℃-800℃.

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