Conductive film and method for producing conductive film

Abstract

To provide a conductive film capable of reducing electrical resistance even by a method other than increasing the amount of conductive filler, and a method for producing the conductive film.SOLUTION: The conductive film comprises a resin, a conductive filler, and a heavy metal deactivator.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a conductive film and a method for manufacturing a conductive film. [Background technology]

[0002] Japanese Patent Laid-Open Publication No. 2019-179732 (Patent Document 1) discloses a conductive film that contains a crystalline olefin resin, a thermoplastic elastomer, and a conductive filler. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-179732 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conductive film disclosed in Patent Document 1, increasing the amount of conductive filler contained in the conductive film is one possible method for reducing the electrical resistance of the conductive film. However, increasing the amount of conductive filler contained in the conductive film causes problems such as making the conductive film brittle.

[0005] The present invention has been made to solve such problems, and its purpose is to provide a conductive film whose electrical resistance can be reduced by methods other than increasing the amount of conductive filler, and a method for manufacturing such a conductive film. [Means for solving the problem]

[0006] A conductive film according to one aspect of the present invention includes a resin, a conductive filler, and a heavy metal deactivator.

[0007] The present inventors have discovered that the addition of a heavy metal deactivator to a conductive film containing a conductive filler reduces the electrical resistance of the film. This conductive film contains a heavy metal deactivator. Therefore, this conductive film can achieve a reduction in electrical resistance due to the heavy metal deactivator.

[0008] The conductive film includes a first layer and a second layer laminated on the first layer, the resin includes a first resin and a second resin, the conductive filler includes a first conductive filler and a second conductive filler, the first layer includes the first resin and the first conductive filler, the second layer includes the second resin and the second conductive filler, and the heavy metal deactivator may be contained in at least one of the first layer and the second layer.

[0009] According to this conductive film, since a heavy metal deactivator is contained in at least one of the first layer and the second layer, a reduction in electrical resistance due to the heavy metal deactivator can be achieved.

[0010] In the conductive film, the first conductive filler may be a carbon-based filler, and the second conductive filler may be a metal-based filler.

[0011] The conductive film may have a volume resistivity of 110 Ω·cm or less.

[0012] In the conductive film, the heavy metal deactivator may be contained in the second layer, and the amount of the heavy metal deactivator added to the second layer may be 0.1% or more and 0.5% or less by weight of the second resin.

[0013] In the conductive film, a metal complex may be formed by the second conductive filler and the heavy metal deactivator.

[0014] The present inventors have discovered that the electrical resistance of a conductive film containing a metal-based filler can be reduced by adding a heavy metal deactivator that complexes the metal-based filler. This conductive film contains a metal-based filler and a heavy metal deactivator that complexes the metal-based filler. Therefore, this conductive film can achieve a reduction in electrical resistance due to the heavy metal deactivator.

[0015] A method for producing a conductive film according to another aspect of the present invention includes the steps of producing a molten material by heating and melting a resin, a conductive filler, and a heavy metal deactivator, and producing a conductive film by extruding the molten material.

[0016] In this method for producing a conductive film, a heavy metal deactivator is added during the production process of the conductive film, and therefore, the conductive film produced by this method can achieve a reduced electrical resistance value due to the heavy metal deactivator. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a conductive film in which the electrical resistance value can be reduced by a method other than increasing the amount of conductive filler, and a method for producing the conductive film. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is a diagram schematically showing a cross section of the conductive film according to the first embodiment. [Figure 2] FIG. 1 is a diagram schematically showing a configuration of a conductive film manufacturing apparatus according to a first embodiment. [Figure 3] FIG. 10 is a diagram schematically showing a cross section of a conductive film according to a second embodiment. [Figure 4] FIG. 10 is a diagram schematically showing the configuration of a conductive film manufacturing apparatus according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] An embodiment according to one aspect of the present invention (hereinafter also referred to as "the present embodiment") will be described in detail below with reference to the drawings. Note that the same or corresponding parts in the drawings are designated by the same reference numerals, and their description will not be repeated. Furthermore, for ease of understanding, each drawing is drawn schematically with objects appropriately omitted or exaggerated.

[0020] [1. Embodiment 1] <1-1. Conductive film structure> FIG. 1 is a schematic diagram showing a cross section of a conductive film 10 according to the first embodiment. The conductive film 10 is used, for example, as a charging film or a discharging film for copiers, printers, and the like, and as various other functional films for electrical and electronic devices and components. As shown in FIG. 1, the conductive film 10 includes a first conductive resin layer 100 and a second conductive resin layer 200. The thickness T1 of the first conductive resin layer 100 is, for example, 1.5 to 5 times the thickness T2 of the second conductive resin layer 200. Each layer will be described below.

[0021] (1-1-1. First conductive resin layer) The first conductive resin layer 100 contains a resin and a conductive filler. An example of the resin is polyolefin. The first conductive resin layer 100 may further contain a heavy metal deactivator. The heavy metal deactivator will be described in detail later.

[0022] Examples of polyolefins include polypropylene (PP) and polyethylene (PE). Polymers containing an α-olefin having 4 to 30 carbon atoms (1-butene, isobutene, 1-hexene, 1-decene, 1-dodecene, etc.) as an essential constituent monomer may also be used as polyolefins. These polyolefins may be used alone or in the form of a mixture of two or more.

[0023] Among polyolefins, polypropylene is preferred from the viewpoint of moisture-proof properties and mechanical strength. Examples of polypropylene include homopolypropylene, random polypropylene, block polypropylene, polypropylene having a long-chain branched structure, and acid-modified polypropylene.

[0024] The conductive filler contained in the first conductive resin layer 100 may be a carbon-based filler. Examples of the carbon-based filler include graphite, carbon black (acetylene black, ketjen black, furnace black, channel black, thermal lamp black, etc.), carbon nanotubes, and mixtures thereof. Among the carbon-based fillers, carbon black is preferred, and acetylene black, furnace black, or mixtures thereof are more preferred.

[0025] (1-1-2. Second conductive resin layer) The second conductive resin layer 200 is formed on the first conductive resin layer 100, and includes a first surface-side layer 210 and a second surface-side layer 220. The first surface 240 is the surface of the first conductive resin layer 100 opposite to the second conductive resin layer 200. The second surface 230 is the surface of the second conductive resin layer 200 opposite to the first conductive resin layer 100.

[0026] Each of the first-surface-side layer 210 and the second-surface-side layer 220 contains a resin and a conductive filler. An example of the resin is polyolefin. For example, the polyolefins exemplified in the description of the first conductive resin layer 100 can be used. The second conductive resin layer 200 may further contain a heavy metal deactivator. The heavy metal deactivator will be described in detail later.

[0027] Examples of the conductive filler contained in the second conductive resin layer 200 include metal-based fillers such as platinum, gold, silver, copper, nickel, titanium, and mixtures thereof. That is, the conductive filler contained in the second conductive resin layer 200 contains at least one metal element selected from the group consisting of platinum, gold, silver, copper, nickel, and titanium. Among these, nickel particles are more preferred as the conductive filler. For example, in the second conductive resin layer 200, the second-surface-side layer 220 contains more conductive filler than the first-surface-side layer 210.

[0028] (1-1-3. Heavy metal deactivator) In general, a method for reducing the electrical resistance of a conductive film is to increase the amount of conductive filler contained in the conductive film, but increasing the amount of conductive filler contained in the conductive film can cause problems such as making the conductive film brittle.

[0029] The present inventor(s) discovered that the electrical resistance of a conductive film containing a conductive filler can be reduced by adding a heavy metal deactivator. In the conductive film 10 according to the first embodiment, a heavy metal deactivator is contained in at least one of the first conductive resin layer 100 and the second conductive resin layer 200. Therefore, the conductive film 10 can achieve a reduction in electrical resistance due to the heavy metal deactivator.

[0030] An example of a heavy metal deactivator is ADK STAB CDA-10 manufactured by ADEKA Corp. The structure of ADK STAB CDA-10 is shown in the following formula.

[0031] [ka] The CAS number for ADK STAB CDA-10 is 32687-78-8. The chemical name is N,N'-Bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine. The molecular weight is 553.

[0032] The amount of the heavy metal deactivator added to the first conductive resin layer 100 is, for example, 0.1% or more and 0.5% or less of the weight of the resin contained in the first conductive resin layer 100. The amount of the heavy metal deactivator added to the second conductive resin layer 200 is, for example, 0.1% or more and 0.5% or less of the weight of the resin contained in the second conductive resin layer 200.

[0033] For example, when the second conductive resin layer 200 contains a heavy metal deactivator, a metal complex is formed between the metal-based filler contained in the second conductive resin layer 200 and the heavy metal deactivator. The formation of the metal complex suppresses, for example, oxidative degradation of the resin caused by the metal-based filler. As a result of the suppression of oxidative degradation of the resin, the electrical resistance value of the conductive film 10 may be reduced.

[0034] Furthermore, the inclusion of a heavy metal deactivator in the first conductive resin layer 100 suppresses oxidative degradation of the carbon-based filler and resin caused by metal impurities contained in the first conductive resin layer 100. As a result of suppressing oxidative degradation of the carbon-based filler and resin, the electrical resistance value of the conductive film 10 may be reduced.

[0035] <1-2. Conductive film manufacturing method> 2 is a diagram schematically illustrating the configuration of a manufacturing apparatus 40 for the conductive film 10 according to the present embodiment 1. The manufacturing apparatus 40 manufactures the conductive film 10. As shown in FIG. 2, the manufacturing apparatus 40 includes a T-die 400, casting rolls 410 and 420, and a take-up roll 430.

[0036] The T-die 400 includes a T-die main body 401 and raw material input sections 440, 450, and 460. Raw materials for forming the second surface side layer 220 are input into the raw material input section 440. For example, polypropylene and nickel are input into the raw material input section 440. A heavy metal deactivator may also be input into the raw material input section 440.

[0037] The raw material for forming the first surface side layer 210 is fed into the raw material feeding section 450. For example, polypropylene and nickel are fed into the raw material feeding section 450. A heavy metal deactivator may also be fed into the raw material feeding section 450. The weight percent concentration of nickel in the raw material fed into the raw material feeding section 450 is lower than the weight percent concentration of nickel in the raw material fed into the raw material feeding section 440.

[0038] Raw materials for forming the first conductive resin layer 100 are input into the raw material input section 460. For example, polypropylene and carbon black are input into the raw material input section 460. A heavy metal deactivator may also be input into the raw material input section 460.

[0039] The T-die body 401 is configured to co-extrude the raw materials fed through the raw material feed sections 440, 450, and 460, thereby fusing the molten raw materials fed into each raw material feed section to form a single integrated film (molten material). The casting rolls 410 and 420 are configured to cool the extruded molten material and send it downstream. The winding roll 430 is configured to pull and wind the molten material cooled by the casting rolls 410 and 420 at a predetermined speed. A roll of conductive film 10 is produced through the manufacturing process in the manufacturing apparatus 40.

[0040] <1-3. Features> As described above, the conductive film 10 according to the first embodiment contains a heavy metal deactivator. Therefore, the conductive film 10 can achieve a reduction in electrical resistance due to the heavy metal deactivator.

[0041] 2. Second Embodiment The conductive film 10 according to the first embodiment has multiple layers. However, the conductive film does not necessarily have to have multiple layers. For example, the conductive film may be composed of a single layer. The conductive film 10A according to the second embodiment has a single layer. The conductive film 10A will be described in detail below.

[0042] <2-1. Conductive film structure> Fig. 3 is a schematic cross-sectional view of a conductive film 10A according to the present embodiment 2. As shown in Fig. 3, the conductive film 10A is composed of one conductive resin layer.

[0043] The conductive film 10A contains a resin, a conductive filler, and a heavy metal deactivator. An example of the resin is polyolefin. For example, the polyolefin may be one of those exemplified in the description of the first conductive resin layer 100 in the first embodiment. For example, the conductive filler may be a carbon-based filler or a metal-based filler. For example, the carbon-based filler may be one of those exemplified in the description of the first conductive resin layer 100 in the first embodiment. For example, the metal-based filler may be one of those exemplified in the description of the second conductive resin layer 200 in the first embodiment. For example, the heavy metal deactivator may be one of those exemplified in the description of the first embodiment.

[0044] <2-2. Conductive film manufacturing method> 4 is a diagram schematically illustrating the configuration of a manufacturing apparatus 40A for the conductive film 10A according to the present embodiment 2. As shown in FIG. 4, the manufacturing apparatus 40A includes a T-die 400A, casting rolls 410 and 420, and a take-up roll 430.

[0045] The T-die 400A is configured to heat and melt the resin, conductive filler, and heavy metal deactivator to produce a molten material and extrude the molten material. The casting rolls 410 and 420 are configured to cool the extruded molten material and send it downstream. The winding roll 430 is configured to pull and wind the molten material cooled by the casting rolls 410 and 420 at a predetermined speed. A roll of the conductive film 10A is produced through the manufacturing process in the manufacturing apparatus 40A.

[0046] <2-3. Features> As described above, the conductive film 10A according to the second embodiment contains a heavy metal deactivator, and therefore, the conductive film 10A can achieve a reduction in electrical resistance due to the heavy metal deactivator.

[0047] 3. Other Embodiments The concept of the above embodiment is not limited to the embodiment described above. An example of another embodiment to which the concept of the above embodiment can be applied will be described below.

[0048] <3-1> The conductive film may be composed of, for example, three or more layers, such as a first layer containing a resin (e.g., PP) and a metal-based filler (e.g., nickel), a second layer containing a resin (e.g., PP) and a carbon-based filler (e.g., carbon black), and a third layer containing a resin (e.g., PP) and a metal-based filler (e.g., nickel).

[0049] The conductive film may also be composed of, for example, a first layer containing a resin (e.g., PP) and a carbon-based filler (e.g., carbon black), a second layer containing a resin (e.g., PP) and a metal-based filler (e.g., nickel), and a third layer containing a resin (e.g., PP) and a carbon-based filler (e.g., carbon black).

[0050] The conductive film may also be composed of, for example, a first layer containing a resin (e.g., PP) and a carbon-based filler (e.g., carbon black), a second layer containing a resin (e.g., PP) and a carbon-based filler (e.g., carbon black), and a third layer containing a resin (e.g., PP) and a carbon-based filler (e.g., carbon black). In these cases, it is sufficient that at least one of the first, second, and third layers contains a heavy metal deactivator.

[0051] <3-2> When the conductive film is composed of two layers, the layer configuration is not limited to that shown in the above-mentioned embodiment 1. The conductive film may be composed of, for example, a first layer containing a resin (e.g., PP) and a metal-based filler (e.g., nickel), and a second layer containing a resin (e.g., PP) and a metal-based filler (e.g., nickel). In this case, the weight percent concentration of the metal-based filler may be different between the first layer and the second layer, or the type of at least one of the resin and the metal-based filler may be different between the first layer and the second layer.

[0052] The conductive film may also be composed of, for example, a first layer containing a resin (e.g., PP) and a carbon-based filler (e.g., carbon black), and a second layer containing a resin (e.g., PP) and a carbon-based filler (e.g., carbon black). In this case, the weight percent concentrations of the carbon-based filler may be different between the first and second layers, or the type of at least one of the resin and the carbon-based filler may be different between the first and second layers.

[0053] The above describes exemplary embodiments of the present invention. That is, the detailed description and the accompanying drawings are disclosed for the purpose of illustrative explanation. Therefore, some of the components described in the detailed description and the accompanying drawings may be non-essential components for solving the problems. Therefore, just because these non-essential components are described in the detailed description and the accompanying drawings, it should not be immediately recognized that these non-essential components are essential.

[0054] Furthermore, the above-described embodiment is merely an example of the present invention in all respects. Various improvements and modifications can be made to the above-described embodiment within the scope of the present invention. In other words, when implementing the present invention, specific configurations can be appropriately adopted depending on the embodiment. [Example]

[0055] Examples of the present invention will be described below, but the present invention is not limited to the following examples.

[0056] [1. Examples and Comparative Examples] The conductive films of the Examples and Comparative Examples were manufactured using a manufacturing apparatus 40 shown in Fig. 2. Specifically, the conductive films of the Examples and Comparative Examples were manufactured by co-extrusion. In the conductive films of the Examples and Comparative Examples, the second conductive resin layer 200 was formed of polypropylene and nickel, and the first conductive resin layer 100 was formed of polypropylene and carbon black.

[0057] In each of the conductive films of the Examples and Comparative Examples, the total thickness of the first conductive resin layer 100 and the second conductive resin layer 200 was 50 μm. The ratio of the thickness of the first conductive resin layer 100 to the thickness of the second conductive resin layer 200 was 3:1.

[0058] In each of the conductive films of the examples and comparative examples, the weight percent concentration of nickel in the second conductive resin layer 200 (each of the first-surface-side layer 210 and the second-surface-side layer 220) was 70 wt %. The weight percent concentration of carbon black in the first conductive resin layer 100 was 30 wt %.

[0059] In the examples and comparative examples, the conductive films were produced at a film-forming speed of 6.0 m / min.

[0060] In each of the conductive films of the Examples, ADK STAB CDA-10 manufactured by ADEKA CORPORATION was added to the second conductive resin layer 200. The amount of ADK STAB CDA-10 added to each of the conductive films of the Examples was 0.3% of the weight of PP in the second conductive resin layer 200. On the other hand, in each of the conductive films of the Comparative Examples, no heavy metal deactivator was added.

[0061] [2. Various measurements] <2-1. Measurement of volume resistivity> The volume resistivity of each of the conductive films of the examples and comparative examples was measured. Specifically, the volume resistivity of each of the conductive films was measured by a method in accordance with JIS K 7194.

[0062] <2-2. Measuring surface resistance> The surface resistance of each conductive film in the Examples and Comparative Examples was measured. Specifically, the surface resistance of each conductive film was measured using the following method. A 30 mm square test piece was cut out, and the surface resistance was measured using a simple low-resistance meter, Loresta AX MCP-T370, manufactured by Nitto Seiko Analytech Co., Ltd. The probe used was a PSP probe, MCP-TP06P RMH112. The resistance value (Ω) measured with the low-resistance meter was multiplied by a correction coefficient (4.532) to obtain the surface resistance (Ω / □).

[0063] [3. Measurement results] The measurement results for each of the conductive films of the Examples and Comparative Examples are shown in Table 1 below.

[0064] [Table 1] As shown in Table 1, the volume resistivity of each conductive film of the Examples was lower than that of the corresponding conductive film of the Comparative Examples, and the surface resistance of each conductive film of the Examples was lower than that of the corresponding conductive film of the Comparative Examples. Of the conductive films of the Examples, those formed at a film-forming speed of 6.0 m / min had a volume resistivity of 110 Ω·cm or less and a surface resistance of 3000 Ω / □ or less. [Explanation of symbols]

[0065] 10, 10A conductive film, 40, 40A manufacturing apparatus, 100 first conductive resin layer, 200 second conductive resin layer, 210 first surface side layer, 220 second surface side layer, 230 second surface, 240 first surface, 400, 400 AT die, 401 T die body, 410, 420 casting roll, 430 winding roll, 440, 450, 460 raw material input section.

Claims

1. Resin and A conductive filler; and a heavy metal deactivator.

2. The first layer, a second layer laminated on the first layer, the resin includes a first resin and a second resin, the conductive filler includes a first conductive filler and a second conductive filler; the first layer includes the first resin and the first conductive filler, the second layer includes the second resin and the second conductive filler, The conductive film according to claim 1 , wherein the heavy metal deactivator is contained in at least one of the first layer and the second layer.

3. the first conductive filler is a carbon-based filler; The conductive film according to claim 2 , wherein the second conductive filler is a metal-based filler.

4. The conductive film according to claim 1 , which has a volume resistivity of 110 Ω·cm or less.

5. the heavy metal deactivator is contained in the second layer; 4. The conductive film according to claim 1, wherein the amount of the heavy metal deactivator added in the second layer is 0.1% or more and 0.5% or less by weight of the second resin.

6. The conductive film according to claim 5 , wherein the second conductive filler and the heavy metal deactivator form a metal complex.

7. producing a molten material by heating and melting a resin, a conductive filler, and a heavy metal deactivator; and producing a conductive film by extruding the molten material.

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