A THB anti-oxidation metallized film and a method for making the same

Abstract

The invention discloses a THB anti-oxidation metallized film, comprising a polymer base film layer, a zinc layer, an anti-oxidation oil film layer, and a polar functional group layer, a first amorphous aluminum oxide layer, and a second amorphous aluminum oxide layer. The polar functional group layer is a polymer base film layer that is subjected to plasma treatment to generate polar functional groups such as C‑O / C‑N, C=O / N‑C=O, and O‑C=O. The first amorphous aluminum oxide layer is formed by vacuum-evaporated metal aluminum combined with oxygen in the polar functional group. The second amorphous aluminum oxide layer is located on the outside of the zinc layer and is formed by metal aluminum combined with oxygen in the external air. The anti-oxidation oil film layer is located on the outermost layer. The outer anti-oxidation oil film layer and the dense amorphous aluminum oxide layer of the metallized film of the invention protect the inner zinc layer from being converted into zinc oxide, and the metallized film is stored for a long time without being oxidized before use.

Description

Technical Field

[0001] The invention belongs to the technical field of metallized film capacitors, and in particular relates to a THB anti-oxidation metallized film and a manufacturing method thereof. Background Art

[0002] The most important part of the metallized film capacitor is the metallized film, which is obtained by vacuum evaporating a metallized layer on a polymer base film layer. The structure and manufacturing process of the metallized film have been disclosed in the prior art.

[0003] For example, the invention patent with the announcement number CN 102796985 A discloses that the metallized film includes an insulating thin film layer and a metal coating plated on the thin film layer, and the metal coating includes a thickened area, a low resistance area and a high resistance area. It also discloses that the coating machine for realizing the metallized film includes a baffle for controlling the penetration amount of metal particles in the vacuum evaporation chamber and a wire feeding gear for determining the density of the metal particles.

[0004] For example, the invention patent with announcement number CN 107993844A discloses an ultra-thin metallized film including a base film and a metal coating, wherein the metal coating includes a thickened area, a gradient square resistance area and a large square resistance area made by a vacuum coating process, wherein the thickened area is a zinc coating, the gradient square resistance area is a zinc-aluminum alloy transition layer, and the large square resistance area is an aluminum coating.

[0005] For example, the invention patent with announcement number CN 108933048A discloses that the manufacturing equipment of the metallized film includes a main roller, a safety film oil printing device, an aluminum evaporation device, a zinc evaporation device, and a protective oil evaporator, and a refrigeration device is arranged in the main roller.

[0006] In the prior art metallized film, the zinc layer is easily oxidized to form unstable zinc oxide when exposed to the outside air. Although the aluminum layer has good antioxidant ability, when moisture invades the capacitor during operation, it will undergo electrochemical reactions and decompose under the action of the AC electric field. In the prior art, a layer of protective oil is added to the outside of the metallized layer to increase the antioxidant ability of the metallized film, but it cannot completely solve the occurrence of electrochemical reactions in THB capacitors.

[0007] Therefore, we proposed a THB anti-oxidation metallized film and a preparation method thereof to solve the above problems. Summary of the invention

[0008] The present invention aims at the problem that the zinc layer in the prior art is easily oxidized to form unstable zinc oxide when exposed to the outside air, and the aluminum layer has good antioxidant ability, but when the capacitor is working, moisture intrudes and decomposes due to electrochemical reaction under the action of AC electric field. The following technical solutions are proposed:

[0009] A THB anti-oxidation metallized film comprises a high molecular polymer base film layer, a zinc layer, an anti-oxidation oil film layer, and also comprises a polar functional group layer, a first amorphous aluminum oxide layer, and a second amorphous aluminum oxide layer. The polar functional group layer is the high molecular polymer base film layer that has been treated with plasma to generate polar functional groups such as CO / CN, C=O / NC=O, and OC=O. The first amorphous aluminum oxide layer is formed by vacuum-evaporated metal aluminum combined with oxygen in the polar functional groups. The second amorphous aluminum oxide layer is located on the outer side of the zinc layer and is formed by metal aluminum combined with oxygen in the external air. The anti-oxidation oil film layer is located on the outermost layer.

[0010] As a preferred embodiment of the above technical solution, the high molecular polymer base film layer is a high temperature resistant polypropylene film for capacitors, and has a thickness of 1.8-15.0 μm.

[0011] As a preferred embodiment of the above technical solution, the weight ratio of the aluminum element to the metal element is 5-8%.

[0012] As a preferred embodiment of the above technical solution, the metal in the zinc layer has a columnar crystal structure, and the size of the columnar crystal structure is 30-50nm. The metallic aluminum first deposited on the high molecular polymer base film layer will diffuse outward along the columnar grain boundary channel, preferentially combine with external oxygen to form aluminum oxide, and form a second amorphous aluminum oxide layer located on the outside of the zinc layer.

[0013] As a preferred embodiment of the above technical solution, when the square resistance of the metallized film is 6-9Ω / □, the thickness of the metallized layer is 20-25nm, the thickness of the first amorphous aluminum oxide layer and the second amorphous aluminum oxide layer is 4-5nm, and the thickness of the zinc layer (4) is 14-16nm.

[0014] As a preferred embodiment of the above technical solution, the thickness of the antioxidant oil film layer is 140-170nm.

[0015] A method for preparing a THB anti-oxidation metallized film, using any one of the THB anti-oxidation metallized films in the above technical solutions, comprising the following steps:

[0016] Step A Vacuum coating:

[0017] 1) The temperature of the workroom where the vacuum coating machine is placed is ≤40℃ and the humidity is ≤40%RH;

[0018] 2) The evaporation of the metallized film is carried out in the vacuum chamber of the vacuum coating machine, and the vacuum degree is ≤2×10 -4 mbar;

[0019] 3) After the polypropylene film is unwound by the unwinding mechanism and subjected to plasma treatment, a gas flow rate of 100 to 150 sccm and a current of 2 to 3 A are set to form a polar functional group layer on the surface of the film;

[0020] 4) The film passes through the shielding oil nozzle, and shielding oil is sprayed on the area of ​​the film that does not require a metallized layer;

[0021] 5) The film passes through the main roller, the bias voltage is set to 30±10V / μm, so that one side of the film is close to the main roller, the temperature of the main roller is -10~-25℃, and the other side passes through the aluminum evaporation source and the zinc evaporation source in turn to receive aluminum and zinc metal vapor deposition;

[0022] 6) The film passes through the anti-oxidation oil pipe, and the oil drop angle is measured using a contact angle meter, with the angle range set to 60±10° to form an anti-oxidation oil film layer;

[0023] 7) The film passes through an infrared heater to warm the metallized film and solidify the metallized layer and the anti-oxidation oil film layer (6);

[0024] 8) The metallized film is rolled up into a metallized film roll by a rolling mechanism;

[0025] 9) After the evaporation is completed, break the vacuum and take out the metallized film roll;

[0026] Step B Time:

[0027] The metallized film roll is placed in the aging room for more than 24 hours. The temperature in the aging room is 25±5℃ and the humidity is ≤35%RH to form the first amorphous aluminum oxide layer. Another part of the metal aluminum will diffuse outward along the columnar grain boundary channel to reach the outside of the zinc layer.

[0028] Step C: Cutting the membrane:

[0029] The metallized film is cut into the required width for capacitor winding and paired. The film cutting is carried out in a workshop with a temperature of 20±10℃, humidity ≤45%RH and a purification level of 10,000. The second amorphous aluminum oxide layer is formed on the outside of the metallized layer of the cut film.

[0030] Step D Vacuum Packaging:

[0031] The cut metallized finished films are paired, placed in aluminum-plastic vacuum bags, desiccant is added, and vacuum sealed for packaging.

[0032] The beneficial effects of the present invention are:

[0033] 1. The anti-oxidation oil film layer and the dense amorphous aluminum oxide layer on the outer layer of the metallized film protect the inner zinc layer from being converted into zinc oxide, and the metallized film can be stored for a long time without oxidation before use;

[0034] 2. Through the method for preparing a THB anti-oxidation metallized film of the present invention, the inner and outer aluminum layers have been basically converted into amorphous aluminum oxide, and the metal zinc component accounts for an absolute majority of the metallized layer (excluding aluminum, accounting for 92-95% by weight of the metallized layer). After being used in THB capacitors, they have passed the double 85 test of capacitor manufacturers and end users. The capacitance change of the capacitor in 1000h is less than 3%, and mass production has been carried out. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The attached figure is a schematic diagram of the structure of a THB anti-oxidation metallized film.

[0036] Legend:

[0037] 1. High molecular polymer base film layer; 2. Polar functional group layer; 3. First amorphous aluminum oxide layer; 4. Zinc layer; 5. Second amorphous aluminum oxide layer; 6. Anti-oxidation oil film layer. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0039] As shown in the accompanying drawings, in an embodiment of the present invention: a THB anti-oxidation metallized film includes a polymer base film layer 1, a polar functional group layer 2, a first amorphous aluminum oxide layer 3, a zinc layer 4, a second amorphous aluminum oxide layer 5, and an anti-oxidation oil film layer 6. The polar functional group layer 2 is the polymer base film layer 1 that has been treated with plasma to produce polar functional groups such as CO / CN, C=O / NC=O, and OC=O. The first amorphous aluminum oxide layer 3 is formed by vacuum-deposited metal aluminum combining with oxygen in the polar functional groups. Because there is no need to obtain oxygen from the outside, the bonding force between the metallized layer and the polymer base film layer is increased. The second amorphous aluminum oxide layer 5 is located on the outside of the zinc layer 4, and is formed by metal aluminum combining with oxygen in the outside air. The anti-oxidation oil film layer 6 is located on the outermost layer.

[0040] As shown in the accompanying drawings, the high molecular polymer base film layer 1 is a high temperature resistant polypropylene film for capacitors, and has a thickness of 1.8-15.0 μm.

[0041] As shown in the attached drawings, aluminum accounts for 5-8% of the weight of metal elements, and is completely converted into amorphous aluminum oxide during the metallization film production process. Therefore, when used on THB capacitors, aluminum no longer exists, and no electrochemical reaction occurs, and the metallization layer remains stable and is not corroded.

[0042] As shown in the accompanying drawings, the metal in the zinc layer 4 presents a columnar crystal structure with a size of 30-50 nm. During the production process of the moisture-proof and oxidation-resistant metallized film, since the aluminum evaporation source is located in front of the zinc evaporation source, the metal aluminum first deposited on the polymer base film layer 1 will diffuse outward along the columnar grain boundary channel. Since the affinity between aluminum and oxygen is greater than the affinity between zinc and oxygen, oxygen preferentially combines with metal aluminum to form aluminum oxide, forming a second amorphous aluminum oxide layer 5 located on the outside of the zinc layer 4. Oxygen is combined with aluminum and it is difficult to form unstable zinc oxide. Aluminum oxide is relatively stable and can form a dense protective layer, which can be stored for a long time before the metallized film is used without oxidation of the internal zinc layer 4.

[0043] As shown in the accompanying drawings, a THB anti-oxidation metallized film, when the metallized film square resistance is 6-9Ω / □, the thickness of the metallized layer is 20-25nm, the thickness of the first amorphous aluminum oxide layer 3 and the second amorphous aluminum oxide layer 5 is 4-5nm, and the thickness of the zinc layer 4 is 14-16nm.

[0044] As shown in the accompanying drawings, a THB anti-oxidation metallized film has an anti-oxidation oil film layer 6 with a thickness of 140-170 nm. The anti-oxidation oil film layer is thicker than the metallized layer to form a dense protection for the internal metallized layer.

[0045] As shown in the accompanying drawings, a method for preparing a THB anti-oxidation metallized film is as follows:

[0046] Step A Vacuum coating:

[0047] 1) The temperature of the workroom where the vacuum coating machine is placed is ≤40℃ and the humidity is ≤40%RH;

[0048] 2) The evaporation of the metallized film is carried out in the vacuum chamber of the vacuum coating machine, and the vacuum degree is ≤2×10 -4 mbar;

[0049] 3) After the polypropylene film is unwound by the unwinding mechanism, it is subjected to plasma treatment, and the gas flow rate is set to 100-150 sccm and the current is set to 2-3A, so that polar functional groups such as CO / CN, C=O / NC=O, OC=O, etc. can be generated to form a polar functional group layer 2 on the surface of the film;

[0050] 4) The film passes through the shielding oil nozzle, and shielding oil is sprayed on the area of ​​the film that does not require a metallized layer to prevent aluminum and zinc from attaching;

[0051] 5) The film passes through the main roller, and the bias voltage is set to 30±10V / μm, so that one side of the film is close to the main roller. The temperature of the main roller is -10~-25℃, and the other side passes through the aluminum evaporation source and the zinc evaporation source in turn to receive aluminum and zinc metal vapor deposition. The low temperature of the main roller is to reduce the temperature of the film, take away the heat of the deposited metal, and prevent the film from being burned;

[0052] 6) The film passes through the anti-oxidation oil pipe, and the oil drop angle is measured using a contact angle meter, and the angle range is set to 60±10° to form an anti-oxidation oil film layer 6;

[0053] 7) The film passes through an infrared heater, which has the following functions: first, to warm the metallized film from below -10°C to a temperature close to the workshop temperature, to prevent moisture in the workshop from being precipitated and adsorbed onto the metallized film roll due to the temperature difference when the metallized film roll is taken out after evaporation, and second, to solidify the metallized layer and the anti-oxidation oil film layer 6;

[0054] 8) The metallized film is rolled up into a metallized film roll by a rolling mechanism;

[0055] 9) After the evaporation is completed, break the vacuum and take out the metallized film roll;

[0056] Step B Time:

[0057] The metallized film roll is placed in the aging room for more than 24 hours. The temperature in the aging room is 25±5℃ and the humidity is ≤35%RH. At this time, the first amorphous aluminum oxide layer 3 has been formed, and another part of the metal aluminum will diffuse outward along the columnar grain boundary channel to the outside of the zinc layer 4. Since the metallized film roll is in a tightly wound state, the metallized film inside cannot contact oxygen, and the aluminum in the outer layer has not been completely converted into aluminum oxide;

[0058] Step C: Cutting the membrane:

[0059] The metallized film is cut into the required width for capacitor winding and paired. The film cutting is carried out in a workshop with a temperature of 20±10℃, a humidity of ≤45%RH and a purification level of 10,000. Since the metallized film roll will be fully unfolded during film cutting, the second amorphous aluminum oxide layer 5 on the outside of the metallized layer will be fully formed;

[0060] Step D Vacuum Packaging:

[0061] The cut metallized finished films are paired, placed in aluminum-plastic vacuum bags, desiccant is added, and vacuum sealed for packaging.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them.

Claims

1. A THB anti-oxidation metallized film, comprising a polymer base film layer (1), a zinc layer (4), and an anti-oxidation oil film layer (6), characterized in that: It also includes a polar functional group layer (2), a first amorphous aluminum oxide layer (3), and a second amorphous aluminum oxide layer (5), wherein the polar functional group layer (2) is a polymer base film layer (1) that has been subjected to plasma treatment to generate polar functional groups of CO / CN, C=O / NC=O, and OC=O, the first amorphous aluminum oxide layer (3) is formed by vacuum-evaporated metal aluminum combined with oxygen in the polar functional groups, the second amorphous aluminum oxide layer (5) is located outside the zinc layer (4), and is formed by metal aluminum combined with oxygen in the outside air, and the anti-oxidation oil film layer (6) is located on the outermost layer; The metal in the zinc layer (4) presents a columnar crystal structure, and the size of the columnar crystal structure is 30-50 nm. The metal aluminum first deposited on the high molecular polymer base film layer (1) diffuses outward along the columnar grain boundary channel and preferentially combines with external oxygen to form aluminum oxide, thereby forming a second amorphous aluminum oxide layer (5) located outside the zinc layer (4); When the square resistance of the metallized film is 6-9Ω / □, the thickness of the metallized layer is 20-25nm, the thickness of the first amorphous aluminum oxide layer (3) and the second amorphous aluminum oxide layer (5) is 4-5nm, and the thickness of the zinc layer (4) is 14-16nm; The thickness of the antioxidant oil film layer (6) is 140-170 nm.

2. A THB anti-oxidation metallized film according to claim 1, characterized in that: The high molecular polymer base film layer (1) is a high temperature resistant polypropylene film for capacitors, and has a thickness of 1.8-15.0 μm.

3. The THB anti-oxidation metallized film according to claim 1, characterized in that: The aluminum element accounts for 5-8% of the metal element weight.

4. A method for preparing a THB anti-oxidation metallized film according to any one of claims 1 to 3, characterized in that: Step A Vacuum coating: 1) The temperature of the workroom where the vacuum coating machine is placed is ≤40℃ and the humidity is ≤40%RH; 2) The evaporation of the metallized film is carried out in the vacuum chamber of the vacuum coating machine, and the vacuum degree is ≤2×10-4mbar; 3) After the polypropylene film is unwound by the unwinding mechanism and subjected to plasma treatment, the gas flow rate is set to 100-150 sccm and the current is set to 2-3A to form a polar functional group layer (2) on the surface of the film; 4) The film passes through the shielding oil nozzle, and shielding oil is sprayed on the area of ​​the film that does not require a metallized layer; 5) The film passes through the main roller, the bias voltage is set to 30±10V / μm, so that one side of the film is close to the main roller, the temperature of the main roller is -10~-25℃, and the other side passes through the aluminum evaporation source and the zinc evaporation source in turn to receive aluminum and zinc metal vapor deposition; 6) The film passes through the anti-oxidation oil tube, and the oil drop angle is measured using a contact angle meter, with the angle range set to 60±10° to form an anti-oxidation oil film layer (6); 7) The film passes through an infrared heater to warm the metallized film and solidify the metallized layer and the anti-oxidation oil film layer (6); 8) The metallized film is rolled up into a metallized film roll by the rolling mechanism; 9) After evaporation is completed, break the vacuum and take out the metallized film roll; Step B Time: The metallized film roll is left in an aging chamber for more than 24 hours, the temperature in the aging chamber is 25±5°C, and the humidity is ≤35%RH, so as to form a first amorphous aluminum oxide layer (3), and a portion of the metal aluminum diffuses outward along the columnar grain boundary channel to reach the outside of the zinc layer (4); Step C: Cutting the membrane: The metallized film is cut into the required width for capacitor winding and paired, and the film cutting is carried out in a workshop with a temperature of 20±10°C, a humidity of ≤45%RH, and a purification level of 100,000, and a second amorphous aluminum oxide layer (5) is formed on the outer side of the metallized layer of the cut film; Step D Vacuum Packaging: The cut metallized finished films are paired, placed in aluminum-plastic vacuum bags, desiccant is added, and vacuum sealed for packaging.

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