Conductive resin composition, sheet, molding, and method for producing conductive resin composition

Abstract

To provide a conductive resin composition having good electrical characteristics while reducing the amount of carbon nanotubes.SOLUTION: The conductive resin composition contains a thermoplastic resin and carbon nanotubes having an aspect ratio of 10,000 or more. The content of the carbon nanotubes is 0.9 pt.mass or more and 1.5 pts.mass or less when the total of the thermoplastic resin and the carbon nanotubes is 100 pts.mass. A molding obtained from the conductive resin composition has a surface resistivity of 1.0×104 Ω / sq. or more and less than 1.0×109 Ω / sq.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to an electrically conductive resin composition, a sheet, a molded article, and a method for producing the electrically conductive resin composition. [Background technology]

[0002] Patent Document 1 discloses a method for producing a conductive resin composition using carbon nanotubes with an average aspect ratio of 371, 56, or 40. It also discloses that a molded product of this conductive resin composition contains 5 parts by mass of carbon nanotubes when the total amount of the thermoplastic resin and the carbon nanotubes is 100 parts by mass. Patent Document 2 discloses a method for producing a conductive resin composition using carbon nanotubes with an average fiber diameter of 150 nm and an average length of 10 μm. It describes that the conductive resin composition contains 23 to 60 parts by mass of carbon nanotubes, where the total amount of the thermoplastic resin and the carbon nanotubes is 100 parts by mass. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-186440 [Patent Document 2] Japanese Patent Application Publication No. 2018-75719 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional conductive resin compositions have had to contain a large amount of carbon nanotubes in order to ensure electrical conduction through contact between the carbon nanotubes.

[0005] The present disclosure aims to provide a conductive resin composition having good electrical properties while reducing the amount of carbon nanotubes. The present disclosure can be realized in the following aspects. [Means for solving the problem]

[0006] A conductive resin composition comprising a thermoplastic resin and carbon nanotubes having an aspect ratio of 10,000 or more, the content of the carbon nanotubes is 0.9 parts by mass or more and 1.5 parts by mass or less, when the total amount of the thermoplastic resin and the carbon nanotubes is 100 parts by mass; The surface resistivity of the molded article obtained from the conductive resin composition is 1.0×10 4 Ω / □ or more 1.0×10 9 The conductive resin composition has a resistivity of less than Ω / □. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a conductive resin composition that has good electrical properties while reducing the amount of carbon nanotubes. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a cross-sectional view of a molded article of a conductive resin composition. DETAILED DESCRIPTION OF THE INVENTION

[0009] Here, a preferred example of the present disclosure will be described. [1] A conductive resin composition comprising a thermoplastic resin and carbon nanotubes having an aspect ratio of 10,000 or more, the content of the carbon nanotubes is 0.9 parts by mass or more and 1.5 parts by mass or less, when the total amount of the thermoplastic resin and the carbon nanotubes is 100 parts by mass; The surface resistivity of the molded article obtained from the conductive resin composition is 1.0×10 4 Ω / □ or more 1.0×10 9 The conductive resin composition has a resistivity of less than Ω / □. [2] The conductive resin composition according to [1], wherein the melt flow rate (MFR) of the thermoplastic resin at 230°C and 2.16 kgf is 0.01 g / 10 min or more and 5 g / 10 min or less. [3] A sheet obtained from the conductive resin composition according to [1] or [2]. [4] A molded article obtained from the conductive resin composition according to [1] or [2]. [5] A method for producing a conductive resin composition containing a thermoplastic resin and carbon nanotubes having an aspect ratio of 10,000 or more, comprising: the content of the carbon nanotubes is 0.9 parts by mass or more and 1.5 parts by mass or less, when the total amount of the thermoplastic resin and the carbon nanotubes is 100 parts by mass; the thermoplastic resin includes a thermoplastic resin (A1) and a thermoplastic resin (A2), a composition containing the thermoplastic resin (A1) and the carbon nanotubes is kneaded using a twin-screw extruder to obtain a masterbatch; A method for producing a conductive resin composition, comprising kneading the masterbatch with the thermoplastic resin (A2).

[0010] The present disclosure will be described in detail below. In this specification, when a numerical range is indicated using "-", it is intended to include both the lower limit and the upper limit unless otherwise specified. For example, the expression "10-20" includes both the lower limit "10" and the upper limit "20". In other words, "10-20" has the same meaning as "10 or more and 20 or less". In addition, in this specification, the upper limit and lower limit of each numerical range can be combined in any way.

[0011] 1. Conductive resin composition 10 The conductive resin composition 10 of this embodiment contains a thermoplastic resin and carbon nanotubes having an aspect ratio of 10,000 or more. The content of the carbon nanotubes is 0.9 parts by mass or more and 1.5 parts by mass or less, where the total of the thermoplastic resin and the carbon nanotubes is 100 parts by mass. The surface resistivity of a molded article 20 obtained from the conductive resin composition 10 is 1.0×10 4Ω / □ or more 1.0×10 9 The conductive resistance is less than Ω / □. The molded article 20 in FIG.

[0012] (1)Thermoplastic resin The thermoplastic resin is not particularly limited. Examples of the thermoplastic resin include polyolefin resins, polystyrene resins, polyamide resins, saturated polyester resins, polyacetal resins, polyphenylene sulfide (PPS), polyphenylene ether (PPE), modified PPE resins obtained by blending or graft polymerizing PPE with other resins (such as polypropylene, nylon, and acrylonitrile-butadiene-styrene copolymers), polymethacrylic resins, polyvinyl chloride resins, and thermoplastic elastomers. The thermoplastic resin may be one type or two or more types.

[0013] The MFR of the thermoplastic resin is not particularly limited. The MFR of the thermoplastic resin (230°C, load 2.16 kg) is preferably 0.01 g / 10 min or more and 5 g / 10 min or less, more preferably 0.01 g / 10 min or more and 3 g / 10 min or less, and even more preferably 0.01 g / 10 min or more and 2 g / 10 min or less. The MFR of the thermoplastic resin can be measured, for example, in accordance with JIS K6921-1:2018.

[0014] From the viewpoints of moldability and cost reduction, the thermoplastic resin is preferably a polyolefin resin, and the polyolefin resin is preferably at least one selected from the group consisting of polypropylene resins, polyethylene resins, ionomers, and polybutene.

[0015] The polypropylene-based resin is, for example, one or more selected from the group consisting of polypropylene, propylene-ethylene copolymer, and propylene-1-butene copolymer. The MFR of the polypropylene resin is not particularly limited. The MFR of the polypropylene resin (JIS K6921-1:2018, 230°C, load 2.16 kg) is preferably 0.01 g / 10 min or more and 5 g / 10 min or less, more preferably 0.01 g / 10 min or more and 3 g / 10 min or less, and even more preferably 0.01 g / 10 min or more and 2 g / 10 min or less. The melting point of the polypropylene-based resin is not particularly limited. The melting point of the polypropylene-based resin is preferably, for example, 150° C. to 165° C. The melting point of the polypropylene-based resin is measured by differential scanning calorimetry (DSC).

[0016] The polyethylene resin is, for example, one or more selected from the group consisting of low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-α-olefin copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methacrylate copolymer. The MFR (melt flow rate) of the polyethylene resin is not particularly limited. The MFR (JIS K6922-1, 190°C, load 2.16 kg) of the polyethylene resin is preferably 0.01 g / 10 min or more and 5 g / 10 min or less, more preferably 0.01 g / 10 min or more and 3 g / 10 min or less, and even more preferably 0.01 g / 10 min or more and 2 g / 10 min or less. The melting point of the polyethylene resin is not particularly limited. The melting point of the polyethylene resin is preferably, for example, 80° C. to 140° C. The melting point of the polyethylene resin is measured by differential scanning calorimetry (DSC). The density of the polyethylene resin is not particularly limited. The density of the polyethylene resin is preferably 0.88 g / cm. 3 -0.94g / cm 3 and more preferably 0.90 g / cm 3 -0.935g / cm 3 and more preferably 0.91 g / cm 3 -0.93g / cm 3 is.

[0017] (2) Carbon nanotubes The carbon nanotubes of the present disclosure are substances in which graphene sheets are arranged in a cylindrical shape. The carbon nanotubes may be multi-walled carbon nanotubes (MWCNTs) or single-walled carbon nanotubes (SWCNTs). Multi-walled carbon nanotubes are preferred in terms of cost and strength. Furthermore, the sidewalls of the carbon nanotubes are not limited to a graphite structure, and at least a portion of the sidewalls may have an amorphous structure.

[0018] Long carbon nanotubes can reduce the number of contact points between carbon nanotubes required for forming conductive paths compared to relatively short carbon nanotubes. Therefore, theoretically, it is believed that long carbon nanotubes can ensure conductivity even when the amount added is reduced. However, it is more difficult to uniformly disperse long carbon nanotubes in a thermoplastic resin than short carbon nanotubes, making it difficult to achieve the desired surface resistivity. After extensive research, the inventors of the present application have found that by setting the aspect ratio of the carbon nanotubes within a predetermined range and the amount of carbon nanotubes added within a predetermined range, the surface resistivity of the molded body 20 can be reduced to 1.0 × 10 4 Ω / □ or more 1.0×10 9 We have now developed a conductive resin composition with a resistivity of less than Ω / □.

[0019] From the viewpoint of optimizing conductivity while reducing the amount of carbon nanotubes added, the aspect ratio of the carbon nanotubes is 10,000 or more, preferably 11,000 or more, and more preferably 15,000 or more. The aspect ratio of the carbon nanotubes may be, for example, 200,000 or less, 150,000 or less, or 100,000 or less. In the present disclosure, the conductive resin composition 10 is only required to contain carbon nanotubes having an aspect ratio within the above range, and may further contain carbon nanotubes having an aspect ratio outside the above range, as long as the effects of the present disclosure are not impaired. The aspect ratio of a carbon nanotube is calculated as the length of the carbon nanotube divided by the diameter of the carbon nanotube. The length and diameter of a carbon nanotube can be measured, for example, by observing the carbon nanotube with an electron microscope.

[0020] The length of the carbon nanotubes is not particularly limited. From the viewpoint of optimizing the conductivity while reducing the amount of carbon nanotubes added, the length of the carbon nanotubes is preferably 200 μm or more, more preferably 400 μm or more, and even more preferably 500 μm or more. The length of the carbon nanotubes may be, for example, 5000 μm or less, 4000 μm or less, or 3000 μm or less.

[0021] The diameter of the carbon nanotube is not particularly limited. From the viewpoint of ensuring a sufficient length of the carbon nanotube, the diameter of the carbon nanotube is preferably 5 nm or more, more preferably 10 nm or more, and even more preferably 15 nm or more. The diameter of the carbon nanotube may be, for example, 100 nm or less, 80 nm or less, or 60 nm or less.

[0022] Such carbon nanotubes are available from carbon nanotube manufacturers. Specific examples include NTF-7, NTF-10, NTF-15, NTF-20, and NTF-30 manufactured by Koatsu Gas Kogyo Co., Ltd.

[0023] The carbon nanotube content is 0.9 parts by mass or more, where the total of the thermoplastic resin and the carbon nanotubes is 100 parts by mass. From the viewpoint of reducing the surface resistivity of the molded body 20, it may be 0.92 parts by mass or more, 0.95 parts by mass or more, or 1.0 parts by mass or more. The carbon nanotube content is 1.5 parts by mass or less, and from the viewpoint of increasing the surface resistivity of the molded body 20, it may be 1.45 parts by mass or less, 1.4 parts by mass or less, or 1.35 parts by mass or less. From these viewpoints, the carbon nanotube content may be 0.9 parts by mass or more and 1.5 parts by mass or less, 0.92 parts by mass or more and 1.45 parts by mass or less, 0.95 parts by mass or more and 1.4 parts by mass or less, or 1.0 parts by mass or more and 1.35 parts by mass or less.

[0024] (3) Other ingredients The conductive resin composition 10 may contain other components in addition to the thermoplastic resin and the carbon nanotubes, such as UV absorbers, stabilizers such as antioxidants, pigments, dyes, fillers, plasticizers, function-imparting agents, and flame retardants.

[0025] 2. Molded body 20 The molded article 20 of the present disclosure is a molded article obtained from the conductive resin composition 10. An example of the molded article 20 in Fig. 1 is a sheet obtained from the conductive resin composition 10. Note that the molded article obtained from the conductive resin composition 10 is not limited to a sheet, and molded articles of various shapes can be obtained depending on the application, etc.

[0026] The surface resistivity of the molded body 20 is 1.0×10 4 Ω / □ or more 1.0×10 9 The surface resistivity of the molded body 20 is less than 5.0×10 4 Ω / □ or more, 1.0×10 5 From the viewpoint of anti-static properties, the surface resistivity of the molded body 20 can be 5.0×10 8 Ω / □ or less, 1.0×10 8The surface resistivity of the molded body 20 can be controlled by adjusting the content of the carbon nanotubes. The technology of the present disclosure can reduce the surface resistivity of the molded body 20 to 1.0×10 4 Ω / □ or more 1.0×10 9 This is particularly useful in that it can be easily optimized to any value in the range of less than Ω / □. The surface resistivity is a value measured as follows.

[0027] <Measurement of surface resistivity> Prepare a rectangular sheet sample of 0.5mm-2mm thick and 15cm x 30cm. For measurement, use a Hozan surface resistance measuring instrument F-109. The applied voltage is 1 x 10 6 If the resistance is less than Ω / □, it is 10V, and the object to be measured is 1×10 6 If the resistivity is Ω / □ or higher, the voltage is 100V. The distance between the pair of electrodes is 15cm. Measurements are taken at the upper right edge, lower right edge, upper left edge, and lower left edge, with the long side of the sample running horizontally. The measurement value 15 seconds after starting the measurement is read as the surface resistivity of the measurement site. The average of the surface resistivities of the measured upper, lower, left, and right edges is calculated and used as the surface resistivity of the sample.

[0028] The thickness of the molded body 20 can be set depending on the application, and may be, for example, 0.2 mm to 10 mm, or 0.5 mm to 5 mm, or 1 mm to 3 mm. The molded body 20 may be composed of the conductive resin composition 10 alone, or may be composed of a material other than the conductive resin composition 10. Even when the molded body 20 is composed of a material other than the conductive resin composition 10, it is preferable that the surface layer of the molded body 20 is composed of the conductive resin composition 10.

[0029] There is no particular limitation on the use of the molded article 20. The molded article 20 has good electrical properties and is therefore suitable as a container for housing an electronic device, a mat for an electronic device, or a housing for an electronic device.

[0030] 3. Method for producing conductive resin composition 10 The method for producing the conductive resin composition 10 is not particularly limited. An example of the method for producing the conductive resin composition 10 will be described. The thermoplastic resin used in the method for producing the conductive resin composition 10 includes a thermoplastic resin (A1) and a thermoplastic resin (A2). In the method for producing the conductive resin composition 10, a composition containing the thermoplastic resin (A1) and carbon nanotubes is kneaded using a twin-screw extruder to obtain a masterbatch, and the masterbatch is then kneaded with the thermoplastic resin (A2). The thermoplastic resin (A2) is also called a diluent resin.

[0031] The thermoplastic resin (A1) and the thermoplastic resin (A2) may be the same type of resin or different types of resin. The combination of the thermoplastic resin (A1) and the thermoplastic resin (A2) is not particularly limited, and they can be appropriately selected and combined from the thermoplastic resins described in "(1) Thermoplastic Resin" in "1. Conductive Resin Composition 10". The thermoplastic resin (A1) and the thermoplastic resin (A2) are preferably one or more resins (A1) selected from polyolefin-based resins and one or more resins (A2) selected from polyolefin-based resins, and more preferably a polypropylene-based resin (A1) and a polypropylene-based resin (A2).

[0032] The mass ratio (A1:A2) of the thermoplastic resin (A1) to the thermoplastic resin (A2) is not particularly limited, and the mass ratio (A1:A2) of the thermoplastic resin (A1) to the thermoplastic resin (A2) is preferably 10:90 to 90:10, more preferably 15:85 to 75:25, and even more preferably 20:80 to 65:35.

[0033] The composition containing the thermoplastic resin (A1) and the carbon nanotubes is kneaded using a twin-screw extruder. The twin-screw extruder can knead the composition with a stronger shear force than that applied when using a kneader or a single-screw extruder. Therefore, the twin-screw extruder can suitably disperse carbon nanotubes having an aspect ratio of 10,000 or more in the thermoplastic resin (A1). In this case, the carbon nanotubes can be more suitably dispersed by using a resin with an MFR (230°C, load 2.16 kg) of 0.01 g / 10 min or more and 5 g / 10 min or less as the thermoplastic resin (A1).

[0034] The masterbatch and thermoplastic resin (A2) may be kneaded using any of a kneader, a single-screw extruder, and a multi-screw extruder. In this case, by using a resin with an MFR (230°C, 2.16 kg) of 0.01 g / 10 min or more and 5 g / 10 min or less as the thermoplastic resin (A2), conductive paths made of carbon nanotubes can be suitably formed. The masterbatch and thermoplastic resin (A2) may be kneaded using a shear force equal to or weaker than that used to knead the composition containing the thermoplastic resin (A1) and carbon nanotubes described above.

[0035] A mixture (kneaded product) of the thermoplastic resin (A1), carbon nanotubes, and thermoplastic resin (A2) is molded to obtain a molded product 20 of the conductive resin composition 10. The molding method for the conductive resin composition 10 is not particularly limited and can be appropriately selected depending on the application. When the molded product 20 of the conductive resin composition 10 is molded into a sheet shape, it can be molded, for example, by an extrusion molding method such as a T-die method. Alternatively, the molded product of the conductive resin composition 10 may be molded by a molding method such as a heat press method.

[0036] 4. Effects of this embodiment The conductive resin composition 10 of this embodiment has good electrical properties. The reason why the conductive resin composition 10 has good electrical properties will be explained below, but the present disclosure is not limited to this reason. The electrical properties required for a product vary depending on its application, and the surface resistivity must be less than 1.0 x 10 4 Ω / □ or more 1.0×10 9 In some cases, a surface resistivity of less than Ω / □ is required. In a conductive resin composition in which conductive carbon is blended with a thermoplastic resin, the surface resistivity at the percolation threshold may be included within the above-mentioned surface resistivity range. The percolation threshold refers to the concentration of conductive carbon at the inflection point at which the electrical resistance of the conductive resin composition changes significantly. In other words, in a conductive resin composition, even a small change in the conductive carbon concentration can have a significant effect on the surface resistivity, raising concerns that precise control of the electrical resistance value may be impossible.

[0037] The conductive resin composition 10 of this embodiment contains a thermoplastic resin and carbon nanotubes with an aspect ratio of 10,000 or more. Carbon nanotubes with an aspect ratio of 10,000 or more have a lower frequency of conductive sites due to contact than carbon nanotubes with the same diameter but an aspect ratio of less than 10,000, and can stably form conductive paths with a small amount. The conductive resin composition 10 of this embodiment contains 0.9 parts by mass or more and 1.5 parts by mass or less of carbon nanotubes with an aspect ratio of 10,000 or more, and thus has a surface resistivity of 1.0×10 4 Ω / □ or more 1.0×10 9 It is estimated that a compact 20 having a hardness of less than Ω / □ can be obtained. [Example]

[0038] The present invention will be explained in more detail below with reference to examples.

[0039] 1. Preparation of a sheet of conductive resin composition Sheets of the conductive resin compositions of Examples 1 to 5 and Comparative Example 1 were prepared using the blending ratios shown in Table 1. Details of the main raw materials listed in Table 1 are shown below. Thermoplastic resin: Polypropylene resin (propylene-ethylene block copolymer), MFR 0.5g / 10min (230℃, 2.16kg), density 0.90g / cm 3 Carbon nanotubes 1: Carbon nanotubes with an aspect ratio of 11667 to 65000, diameter 20nm to 60nm, length 0.7mm to 1.3mm, manufactured by Koatsu Gas Kogyo Co., Ltd., NTF-10 Carbon nanotubes 2: Carbon nanotubes with an aspect ratio of 450 to 3000, diameter 7nm-11nm, length 5μm-20μm, manufactured by Cnano, FT7000 series powder

[0040] [Table 1]

[0041] Example 1 Specifically, the sheet of the conductive resin composition of Example 1 was produced as follows. 3 / 10 of the total amount of thermoplastic resin listed in Table 1 was blended with 1.45 parts by mass of carbon nanotubes 1, and the blend was placed in a co-rotating twin-screw extruder (HYPERKTX30MX, manufactured by Kobe Steel, Ltd.). The mixture was kneaded at a rotation speed of 600 rpm, a cylinder temperature of 110°C, and a discharge rate of 20 kg / h, and then cut with a pelletizer to obtain pellets (master batch). The resulting pellets were blended with 7 / 10 of the total amount of thermoplastic resin, and the blend was placed in a T-die extruder (GT-20-A, manufactured by the Plastics Engineering Research Institute). The mixture was kneaded at a rotation speed of 130 rpm, a cylinder temperature of 210°C, and a discharge rate of 2.5 kg / h, and then a 0.5 mm thick sheet was obtained using the T-die method.

[0042] Example 2 A sheet was obtained in the same manner as in Example 1, except that the blending amount of carbon nanotubes 1 was set to 0.925 parts by mass. Comparative Examples 1 and 4 Sheets were obtained in the same manner as in Example 1, except that the blending amounts of carbon nanotubes 1 were 0.8 parts by mass and 2 parts by mass, respectively. Comparison Example 2 The total amount of thermoplastic resin listed in Table 1 was blended with 1.45 parts by mass of carbon nanotubes 1, and the mixture was charged into a T-die extruder (GT-20-A model, manufactured by Plastics Engineering Research Institute). After kneading under conditions of a rotation speed of 130 rpm, a cylinder temperature of 210°C, and a discharge rate of 2.5 kg / h, a sheet with a thickness of 0.5 mm was obtained by the T-die method. Comparative Examples 3 and 5 Sheets were obtained in the same manner as in Example 1, except that carbon nanotubes 1 were replaced with 1.45 parts by mass and 0.8 parts by mass of carbon nanotubes 2.

[0043] 2. Evaluation Method If masterbatching is performed using a twin-screw extruder, the "Masterbatching" column in Table 1 will show "Sufficient." If masterbatching is not performed using a twin-screw extruder, the "Masterbatching" column in Table 1 will show "Not sufficient."

[0044] The surface resistivity of the sheets of the examples and comparative examples was measured by the method of "Measurement of surface resistivity" described in the embodiments. Based on the surface resistivity, the electrical properties of the sheets of the examples and comparative examples were evaluated according to the following criteria. Pass: Surface resistivity is 1.0 x 10 6 Ω / □ or more 1.0×10 9 It is less than Ω / □. Fail: Surface resistivity is 1.0 x 10 6 Ω / □ or less than 1.0×10 9 It is Ω / □ or more.

[0045] 3.Results The results are shown in Table 1. (1) Fulfillment of each requirement in the examples and comparative examples The conductive resin compositions of Examples 1 and 2 satisfy all of the following requirements (a) to (d). · Requirement (a): Contains thermoplastic resin. Requirement (b): Contains carbon nanotubes with an aspect ratio of 10,000 or more. Requirement (c): The carbon nanotube content is 0.9 parts by mass or more and 1.5 parts by mass or less, where the total of the thermoplastic resin and the carbon nanotubes is 100 parts by mass. Requirement (d): The surface resistivity of a molded article obtained from the conductive resin composition is 1.0 × 10 4 Ω / □ or more 1.0×10 9 It is less than Ω / □.

[0046] In contrast, the conductive resin composition of Comparative Example 1 does not satisfy the requirements (c) and (d). The conductive resin composition of Comparative Example 2 does not satisfy the requirement (d). The conductive resin composition of Comparative Example 3 does not satisfy the requirements (b) and (d). The conductive resin composition of Comparative Example 4 does not satisfy the requirements (c) and (d). The conductive resin composition of Comparative Example 5 does not satisfy the requirements (b), (c), and (d).

[0047] Furthermore, the conductive resin compositions of Examples 1 and 2 also satisfy the following requirements. Requirement (e): The melt flow rate (MFR) of the thermoplastic resin at 230°C and 2.16 kgf is 0.01 g / 10 min or more and 5 g / 10 min or less.

[0048] Furthermore, the methods for producing the conductive resin compositions of Examples 1 and 2 satisfy all of the following requirements (f) to (i). · Requirement (f): Contains thermoplastic resin. Requirement (g): Contains carbon nanotubes with an aspect ratio of 10,000 or more. Requirement (h): The carbon nanotube content is 0.9 parts by mass or more and 1.5 parts by mass or less, where the total of the thermoplastic resin and the carbon nanotubes is 100 parts by mass. Requirement (i): The thermoplastic resin includes a thermoplastic resin (A1) and a thermoplastic resin (A2), and a composition including the thermoplastic resin (A1) and carbon nanotubes is kneaded using a twin-screw extruder to obtain a masterbatch, and the masterbatch and the thermoplastic resin (A2) are kneaded together.

[0049] In contrast, the conductive resin composition of Comparative Example 1 does not satisfy requirement (h). The conductive resin composition of Comparative Example 2 does not satisfy requirement (i). The conductive resin composition of Comparative Example 3 does not satisfy requirement (g). The conductive resin composition of Comparative Example 4 does not satisfy requirement (h). The conductive resin composition of Comparative Example 5 does not satisfy requirements (g) and (h).

[0050] (2) Results and Discussion The conductive resin compositions of Examples 1 and 2 were judged to be pass, whereas the conductive resin composition of Comparative Examples 1-5 was judged to be fail. It was found that when requirements (a)-(d) are satisfied, the material has good electrical properties. In addition, when the requirements (f)-(i) are satisfied, the surface resistivity of the molded article is preferably 1.0×10 4 Ω / □ or more 1.0×10 9 It was found that a value of less than Ω / □ could be achieved.

[0051] 5. Effects of the Example According to the above examples, it is possible to provide a conductive resin composition having good electrical properties while reducing the amount of carbon nanotubes.

[0052] The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible. [Explanation of symbols]

[0053] 10...Conductive resin composition 20...Molded body

Claims

1. A conductive resin composition comprising a thermoplastic resin and carbon nanotubes having an aspect ratio of 10,000 or more, the content of the carbon nanotubes is 0.9 parts by mass or more and 1.5 parts by mass or less, when the total amount of the thermoplastic resin and the carbon nanotubes is 100 parts by mass; The surface resistivity of the molded article obtained from the conductive resin composition is 1.0×10 ４ Ω / □ or more 1.0×10 ９ The conductive resin composition has a resistance of less than Ω / □.

2. 2. The conductive resin composition according to claim 1, wherein the thermoplastic resin has a melt flow rate (MFR) at 230°C and 2.16 kgf of 0.01 g / 10 min or more and 5 g / 10 min or less.

3. A sheet obtained from the conductive resin composition according to claim 1 or 2.

4. A molded article obtained from the conductive resin composition according to claim 1 or 2.

5. A method for producing a conductive resin composition containing a thermoplastic resin and carbon nanotubes having an aspect ratio of 10,000 or more, the method comprising: the content of the carbon nanotubes is 0.9 parts by mass or more and 1.5 parts by mass or less, when the total amount of the thermoplastic resin and the carbon nanotubes is 100 parts by mass; the thermoplastic resin includes a thermoplastic resin (A1) and a thermoplastic resin (A2), a composition containing the thermoplastic resin (A1) and the carbon nanotubes is kneaded using a twin-screw extruder to obtain a masterbatch; A method for producing a conductive resin composition, comprising kneading the masterbatch and the thermoplastic resin (A2).

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