Resin composite material containing carbon nanotubes, and method for producing the same

Abstract

To provide a resin composite material comprising an antistatic layer that uses carbon nanotubes as a conductive material on a thermoplastic resin substrate, the resin composite material having sufficient antistatic performance despite a small concentration of carbon nanotubes contained in the antistatic layer and maintaining high transparency.SOLUTION: A resin composite material comprises, on a thermoplastic resin substrate (A), an antistatic layer (B). The resin composite material has a surface resistance value of 1×107 Ω / sq. to less than 1×1013 Ω / sq. and has a total light transmittance in a visible light region of 80% or more. The antistatic layer (B) is at least composed of carbon nanotubes (b1) and a polycarbonate resin (b2). The concentration of the carbon nanotubes (b1) in the antistatic layer (B) is 0.005 mass% to 0.1 mass%.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin composite material containing carbon nanotubes and a method for producing the same.

Background Art

[0002] The conductivity of general-purpose thermoplastic resins is low, and in order to impart conductivity, it has been expressed by dispersing a conductive material in the resin. Conventionally, carbon black, ketjen black, and graphite have been used as the conductive material. However, with these conductive materials, it has been necessary to blend a large amount of the conductive material with respect to the resin. Moreover, because the blending amount is large, it has been unsuitable for applications that require transparency.

[0003] In response to such problems, Patent Document 1 proposes a composition in which an energy ray-curable resin and conductive particles such as ZnO, ITO, ATO, and SbO2 are blended in an antistatic layer. However, since such conductive particles are usually blended in a large amount of 1% by mass or more, they affect properties such as the strength and optical properties of the molded product.

[0004] Further, Patent Document 2 proposes a dispersion liquid of carbon nanotubes containing carbon nanotubes, a dispersant, an organic solvent, and / or a resin component. However, although the surface resistance value is in the range of 10 6 ~10 9 Ω / sq., the concentration of carbon nanotubes in the total solid content of the coating film is as high as 20% to 33%, and the total light transmittance, which is an index of transparency, is 80% or less, and transparency and conductivity have not been achieved simultaneously.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention is a resin composite material having an antistatic layer using carbon nanotubes as a conductive material on a thermoplastic resin substrate, and despite the low concentration of carbon nanotubes contained in the antistatic layer, sufficient antistatic performance is imparted, and a resin composite material that maintains high transparency is provided.

[0007] The present inventor conducted intensive studies to solve the above problems. As a result, it was found that (A) an antistatic layer formed on a thermoplastic resin substrate contains at least (b1) carbon nanotubes and (b2) a polycarbonate resin, and despite the low concentration of (b1) carbon nanotubes contained in the (B) antistatic layer, antistatic properties can be sufficiently exhibited, and furthermore, the obtained resin composite material does not significantly impair the total light transmittance in the visible light region of the (A) thermoplastic resin substrate.

[0008] The present invention was completed by further studies based on the above findings.

[0009] Aspects of the present invention are as follows. Item 1 A resin composite material having (B) an antistatic layer on (A) a thermoplastic resin substrate, The surface resistance value is 1×10 7 Ω / sq. to less than 1×10 13 Ω / sq., and a resin composite material having a total light transmittance of 80% or more in the visible light region, The (B) antistatic layer is composed of at least (b1) carbon nanotubes and (b2) a polycarbonate resin, A resin composite material in which the concentration of (b1) carbon nanotubes in the (B) antistatic layer is 0.005% by mass to 0.1% by mass. Item 2. The resin composite according to Item 1, wherein the thickness of the (B) antistatic layer is 0.1 μm or more and 20 μm or less. Item 3. The resin composite according to any one of Items 1 or 2, wherein the outer diameter of the (b1) carbon nanotube in the (B) antistatic layer is 0.1 nm or more and 5 nm or less. Item 4. A manufacturing method for obtaining the resin composite according to any one of Items 1 to 3, comprising: a step of preparing a carbon nanotube dispersion liquid containing at least (b1) carbon nanotubes, (b2) a polycarbonate resin, and (b3) a polar solvent; a step of applying the carbon nanotube dispersion liquid onto the (A) thermoplastic resin substrate; a step of drying the carbon nanotube dispersion liquid applied onto the (A) thermoplastic resin substrate to form the (B) antistatic layer. The manufacturing method of the resin composite. Item 5. The manufacturing method of the resin composite according to Item 4, wherein in the step of preparing the carbon nanotube dispersion liquid, the concentration of the (b3) polar solvent is 80 to 99% by mass with respect to the total composition of the carbon nanotube dispersion liquid. Item 6. The manufacturing method of the resin composite according to any one of Items 4 or 5, wherein the (b3) polar solvent is at least one selected from the group consisting of a halogen-based solvent, an ether-based solvent, a ketone-based solvent, an amine-based solvent, an amide-based solvent, a nitro-based solvent, and an aromatic hydrocarbon-based solvent.

Advantages of the Invention

[0010] According to the present invention, a resin composite having sufficient antistatic properties and transparency can be obtained.

Best Mode for Carrying Out the Invention

[0011] The resin composite material of the present invention is composed of (A) a thermoplastic resin substrate and (B) an antistatic layer formed on the (A) thermoplastic resin substrate. The (B) antistatic layer can be formed by applying and drying a carbon nanotube dispersion liquid containing at least (b1) carbon nanotubes, (b2) a polycarbonate resin, and (b3) a polar solvent on the (A) thermoplastic resin substrate. By setting the concentration of (b1) carbon nanotubes contained in the (B) antistatic layer to 0.005 to 0.1% by mass, sufficient antistatic properties can be obtained. Furthermore, the total light transmittance in the visible light region originally possessed by the (A) thermoplastic resin substrate is not significantly impaired, and it has excellent transparency. Hereinafter, the resin composite material of the present invention will be described in detail.

[0012] In this specification, the numerical values connected by "~" mean a numerical range including the numerical values before and after "~" as the lower limit value and the upper limit value. When a plurality of lower limit values and a plurality of upper limit values are separately described, any lower limit value and upper limit value can be selected and connected by "~" (however, when connecting the upper limit value expressed as "less than" by "~", the numerical value after "~" (i.e., the upper limit value) is not included in the numerical range).

[0013] Resin composite material The resin composite material of the present invention is composed of (A) a thermoplastic resin substrate and (B) an antistatic layer. The (B) antistatic layer is obtained by applying and drying a carbon nanotube dispersion liquid containing at least (b1) carbon nanotubes, (b2) a polycarbonate resin, and (b3) a polar solvent on the (A) thermoplastic resin substrate.

[0014] (A) Thermoplastic resin substrate In the resin composite material of the present invention, the (A) thermoplastic resin substrate is not particularly limited as long as a resin having a thickness of 2 mm and a total light transmittance in the visible light region (380 nm to 780 nm) of 80% or more is used. It may be the same as or different from the (b2) polycarbonate resin contained in the (B) antistatic layer. Specific examples include polyvinyl chloride resin (PVC resin), polystyrene resin (PS resin), acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyester resin (PEs resin), polycarbonate resin (PC resin), polymethyl methacrylate resin (PMMA resin), polyethersulfone resin (PES resin), polyarylate resin (PAR resin), polysulfone resin (PSU resin), and the like. In particular, it is preferable to use PVC resin, PC resin, and PMMA resin having a high total light transmittance in the visible light region. The total light transmittance in the visible light region can be measured according to JIS K7361-1, which is a JIS standard. The specific measurement method is as described in the examples.

[0015] (A) Various additives such as antioxidants, ultraviolet absorbers, plasticizers, pigments, and dyes may be blended in the thermoplastic resin substrate as needed. Also, surface modification treatment may be performed on one or both sides. By performing the surface modification treatment, the adhesion to the antistatic layer can be improved in the present invention. Examples of the surface modification treatment include energy ray irradiation treatment (corona discharge treatment, plasma treatment, electron beam irradiation treatment, ultraviolet irradiation treatment) and chemical treatment (immersion in an aqueous solution of an oxidizing agent such as potassium dichromate solution or concentrated sulfuric acid), and any method can be used.

[0016] (A) The thickness of the thermoplastic resin substrate is appropriately selected according to the application as needed, such as when flexibility is required like in the case of films or tapes, or when rigidity is required like in the case of molded bodies such as trays or boards, and is not particularly limited, but is preferably 0.01 to 10 mm.

[0017] (B) Antistatic layer The (B) antistatic layer in the resin composite material of the present invention is obtained by applying and drying a carbon nanotube dispersion liquid containing at least (b1) carbon nanotubes, (b2) polycarbonate resin, and (b3) a polar solvent on the (A) thermoplastic resin substrate.

[0018] (b1) Carbon nanotube The (b1) carbon nanotubes used in the present invention are not particularly limited and may be carbon nanotubes produced by any of the arc discharge method, laser evaporation method, and chemical vapor deposition (CVD) method, which are known as general production methods. Considering the purity and productivity of carbon nanotubes, it is preferable to use carbon nanotubes produced by the chemical vapor deposition (CVD) method. Also, the type of carbon nanotubes is not particularly limited and may be single-walled carbon nanotubes, double-walled carbon nanotubes, or multi-walled carbon nanotubes.

[0019] From the viewpoint of more preferably exerting the effects of the present invention, the outer diameter of the (b1) carbon nanotubes is not particularly limited, but the lower limit is preferably 1.0 nm or more, more preferably 1.2 nm or more, and even more preferably 1.5 nm or more. The upper limit is preferably 5.0 nm or less, more preferably 3.0 nm or less, and even more preferably 2.0 nm or less. The outer diameter of the carbon nanotubes can be measured 100 times by selectively using a Raman spectrometer and a transmission electron microscope, and the average value can be used as the outer diameter.

[0020] From the viewpoint of more preferably exerting the effects of the present invention, the length of the (b1) carbon nanotube is not particularly limited, but the lower limit may be 10 nm or more, 10 μm or more, 1 mm or more, 10 mm or more, and the upper limit is 100 mm or less. The measurement method is not particularly limited either, and it may be the length of a single carbon nanotube, or it may be in a state where the carbon nanotubes are aggregated with each other to form a bundle (bundle state).

[0021] Further, the G / D ratio, which is the intensity ratio of the G band to the D band of the (b1) carbon nanotube, is preferably 10 or more, preferably 20 or more, and more preferably 30 or more as the lower limit. The G / D ratio is measured by a Raman spectrometer, and in the Raman spectrum measured by the resonance Raman scattering method (excitation wavelength 532 nm), the G band (around 1590 cm -1 -1) and the D band (around 1300 cm -1 -1). It is shown that the higher the G / D ratio, the smaller the amount of defects in the structure of the carbon nanotube.

[0022] The carbon purity of the (b1) carbon nanotube is not particularly defined, but is, for example, 95% or more, preferably 98% or more, and more preferably 99% or more. By removing impurities such as metals as much as possible, the dispersibility of the carbon nanotube can be improved.

[0023] (b2) Polycarbonate resin The (b2) polycarbonate resin used in the present invention may be composed of a polycarbonate resin alone or an alloy with another resin, and is not particularly limited. Also, depending on the use and environment, as other components, it may contain known additives such as light blockers, ultraviolet absorbers, plasticizers, lubricants, fillers, colorants, stabilizers, lubricants, crosslinking agents, anti-blocking agents, antioxidants, etc.

[0024] The polycarbonate resin used in the present invention may be a commercially available product. Specific examples include the Panlite series manufactured by Teijin Limited, the Iupilon series and Novarex series manufactured by Mitsubishi Engineering-Plastics Corporation, the Polyace series manufactured by Sumitomo Bakelite Co., Ltd., the SD Polyca series manufactured by Sumika Polycarbonate Co., Ltd., and the like.

[0025] (b3) Polar solvent The (b3) polar solvent used in the present invention is not particularly limited. For example, halogen-based solvents such as methylene chloride, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, 1-chlorobutane, and chlorobenzene; ether-based solvents such as diethyl ether, tetrahydrofuran, and 1,4-dioxane; ketone-based solvents such as methyl ethyl ketone, acetone, and cyclohexanone; acetate-based solvents such as propylene glycol monomethyl ether acetate; lactone-based solvents such as γ-butyrolactone; carbonate-based solvents such as ethylene carbonate and propylene carbonate; amine-based solvents such as triethylamine and pyridine; nitrile-based solvents such as acetonitrile; amide-based solvents such as N,N'-dimethylformamide, N,N'-dimethylacetamide, tetramethylurea, 2-pyrrolidone, and N-methyl-2-pyrrolidone; nitro-based solvents such as nitromethane and nitrobenzene; aromatic hydrocarbon-based solvents such as toluene and xylene; sulfide-based solvents such as dimethyl sulfoxide and sulfolane; phosphate-based solvents such as hexamethylphosphoric triamide and tri-n-butyl phosphate; alcohol-based solvents such as methanol, ethanol, and 1-propanol; and organic acid-based solvents such as formic acid, acetic acid, and propionic acid.

[0026] Among the above-mentioned (b3) polar solvents, halogen solvents, ether solvents, ketone solvents, amine solvents, nitro solvents, amide solvents, and aromatic hydrocarbon solvents are preferred. At least one selected from the group consisting of methylene chloride, chloroform, diethyl ether, tetrahydrofuran, 1,4-dioxane, methyl ethyl ketone, acetone, cyclohexanone, triethylamine, pyridine, acetonitrile, N,N'-dimethylformamide, N,N'-dimethylacetamide, tetramethylurea, 2-pyrrolidone, N-methyl-2-pyrrolidone, toluene, and xylene is preferred, and it is more preferred to use methylene chloride, chloroform, 2-pyrrolidone, tetrahydrofuran, toluene, cyclohexanone, and N-methyl-2-pyrrolidone.

[0027] The concentration of the (b3) polar solvent used in the present invention is not particularly limited as long as the carbon nanotubes can be uniformly dispersed when producing the carbon nanotube dispersion liquid, and the viscosity can be adjusted according to the coating method of the antistatic layer. As a specific example, as the lower limit, it is preferably 84% by mass or more, and more preferably 86% by mass or more. As the upper limit, it is preferably 94% by mass or less, and more preferably 92% by mass or less.

[0028] In addition, as long as the effects of the present invention are not inhibited, other compounding agents may be contained. Examples of other compounding agents include adhesion promoters, defoaming agents, surface modifiers, etc. They can be appropriately selected from known ones according to the use of the resin composite material of the present invention.

[0029] (b3) Method for producing carbon nanotube dispersion The carbon nanotube dispersion liquid used in the present invention can be produced by mixing or dispersing (b1) carbon nanotubes, (b2) polycarbonate resin, and (b3) polar solvent and compounding agents to be blended as needed. These mixing or dispersion methods may be carried out by a method in which (b1) each component can be uniformly dispersed or mixed to such an extent that no aggregates of carbon nanotubes can be visually confirmed, and are not particularly limited. Examples of the dispersion device include a homogenizer, bead mill, ball mill, basket mill, attrition mill, universal stirrer, clear mixer, ultrasonic wave, jet mill, shear dispersion treatment, etc. For the shear dispersion treatment, products such as "Nanojet Pul JN20" (manufactured by Tsunehikari Co., Ltd.) and "Nanovita L-ES" (manufactured by Yoshida Kikai Kogyo Co., Ltd.) can be used.

[0030] (b4) Method for producing resin composite material As a method for producing the resin composite material, it can be obtained by forming (B) an antistatic layer on (A) a thermoplastic resin substrate. The method for forming (B) the antistatic layer is not particularly limited, and examples thereof include a method of applying a carbon nanotube dispersion liquid on (A) the thermoplastic resin substrate and then drying it, or a method of spraying a carbon nanotube dispersion liquid on (A) the thermoplastic resin substrate and then drying it.

[0031] The method of applying the carbon nanotube dispersion liquid to (A) the thermoplastic resin substrate is not particularly restricted, but the carbon nanotube dispersion liquid can be applied onto the thermoplastic resin substrate by a suitable method from, for example, screen printing, bar coater, knife coater, spin coater, applicator, etc., according to the target coating film thickness. It can also be applied by spray coating using a sprayer.

[0032] As a method for drying the (b3) polar solvent contained in the coating film, conventional drying equipment such as a heater type, hot air drying type, infrared irradiation type, vacuum type, etc. can be used. To remove the (b3) polar solvent, for example, the temperature is about 20°C to 100°C, and it is preferable to raise the temperature step by step so that no bubble marks are formed in the (B) antistatic layer. Regarding the drying time, it is preferably carried out for about 20 minutes to 240 minutes at each temperature raised step by step. Also, as the environment inside the drying equipment, as described above, either a normal pressure state or a vacuum state may be used as long as no bubble marks are formed in the (B) antistatic layer.

[0033] The concentration of (b1) carbon nanotubes in the antistatic layer (B) obtained by drying may be 0.005% by mass or more, may be 0.0075% by mass or more, and may be 0.01% by mass or more as the lower limit. Also, as the upper limit, it may be 0.1% by mass or less, may be 0.075% by mass or less, and may be 0.05% by mass or less. By being in this range, good results can be obtained from the viewpoints of conductivity and total light transmittance in the visible light region.

[0034] The concentration of (b2) polycarbonate resin in the antistatic layer (B) obtained by drying may be 96.99% by mass or more, may be 96.9925% by mass or more, and may be 96.995% by mass or more as the lower limit. Also, as the upper limit, it may be 99.95% by mass or less, may be 99.925% by mass or less, and may be 99.9% by mass or less.

[0035] The concentration of other compounding agents in the antistatic layer (B) obtained by drying is preferably 3% by mass or less. Other compounding agents may not be included, and it may be composed of substantially only (b1) carbon nanotubes and (b2) polycarbonate resin.

[0036] The thickness of the antistatic layer (B) after drying is preferably 0.1 μm or more, more preferably 1.0 μm or more, and even more preferably 2.0 μm or more. Also, as the upper limit, it is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 12 μm or less.

[0037] In the present invention, in order to achieve both conductivity and transparency, it is preferable to satisfy the following relational expression with respect to the carbon nanotube concentration (% by mass) and film thickness (μm) in the antistatic layer. Relational expression: 0.001 ≤ carbon nanotube concentration × film thickness 2 <5

[0038] The resin composite material of the present invention obtained by the above manufacturing method has excellent antistatic properties, and since it does not significantly impair the total light transmittance in the visible light region originally possessed by the (A) thermoplastic resin substrate, it can be suitably used for applications where conductivity and transparency are required.

[0039] Regarding the conductivity of the resin composite material of the present invention, as the lower limit, it is preferably 1×10 7 Ω / sq. or more, more preferably 2.5×10 7 Ω / sq. or more, and even more preferably 5×10 7 Ω / sq. or more. As the upper limit, it is preferably less than 1×10 13 Ω / sq., more preferably 7.5×10 12 Ω / sq. or less, and even more preferably 5×10 12 Ω / sq. or less. Being within this numerical range, sufficient conductivity is ensured for applications where antistatic properties are required, so it can be suitably used.

[0040] Regarding the total light transmittance of the resin composite material of the present invention in the visible light region, it is preferably 80% or more, more preferably 82% or more, and even more preferably 84% or more. Being above this numerical value, it can be suitably used for applications that require transparency.

Examples

[0041] Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited thereto.

[0042] First, the materials used in the following examples and comparative examples will be described below. Note that carbon nanotubes may also be referred to as CNT for short. (A) Thermoplastic resin substrate PC resin substrate, manufactured by AS ONE, thickness 2 mm, total light transmittance 89% PMMA resin substrate, manufactured by AS ONE, thickness 2 mm, total light transmittance 89% (B) Antistatic layer (b1) Carbon Nanotube Carbon Nanotube, manufactured by Osaka Soda, single-walled CNT, outer diameter 2.0 nm, G / D ratio 76 Carbon Black, manufactured by Mitsubishi Chemical, #960 (comparative material) (b2) Polycarbonate Resin Polycarbonate Resin, manufactured by Teijin, Panlite L-1225Y Polymethyl Methacrylate Resin, manufactured by Mitsubishi Chemical, Acrypet VH001 (comparative material) (b3) Polar Solvent Chloroform, manufactured by Wako Pure Chemical Industries, Ltd.

[0043] Subsequently, the evaluation method will be described below.

[0044] (Thickness of the Antistatic Layer) The thickness of the antistatic layer of the resin composite can be measured using a micrometer to measure the thickness of the substrate before coating the carbon nanotube dispersion and the thickness of the resin composite after the drying process, and the difference is taken as the thickness of the antistatic layer. For condition stabilization, it was left standing for 48 hours under the conditions of 23°C and 50% RH before measurement, and the measurement was also carried out under the same conditions.

[0045] (Surface Resistivity) The surface resistivity of the antistatic layer of the resin composite was measured using a high-resistance meter (High Resista-UX MCP-HT800, manufactured by Nitto Seiko Analytic). For condition stabilization, it was left standing for 48 hours under the conditions of 23°C and 50% RH before measurement, and the measurement was also carried out under the same conditions. The molding surface was measured at 3 locations with an applied voltage of 10 V, and the average value was taken as the surface resistivity. The evaluation criteria were set as follows for evaluation. 〇: Less than 1×10 13 Ω / sq. ×: 1×10 or more 13 Ω / sq.

[0046] (Total Light Transmittance) Based on JIS K-7361-1 (Plastics - Test Method for Total Light Transmittance of Transparent Materials - Part 1: Single Beam Method), the total light transmittance of the resin composite material was measured at a measurement wavelength of 380 - 780 nm using an ultraviolet - visible - near infrared spectrophotometer (UV-3600i manufactured by SHIMADZU, using the integrating sphere unit ISR-603). Also, the evaluation criteria were set as follows and the evaluation was carried out. 〇: 80% or more ×: Less than 80%

[0047] [Preparation Example 1] Carbon Nanotube Dispersion Liquid 1 As shown in the composition in Table 1, 0.0025% by mass of carbon nanotubes, 9.9975% by mass of polycarbonate resin, and 90% by mass of chloroform were weighed respectively, and shaken for 1 hour using a shaker to dissolve the resin components. Next, a rough pulverization and rough dispersion treatment of carbon nanotubes was carried out for 10 minutes using a homomixer (TK Robomix, manufactured by Primix Corporation). Subsequently, a fine dispersion treatment of carbon nanotubes was carried out using a high - pressure emulsification dispersion device (Nano - Veta L-ES, manufactured by Yoshida Kikai Kogyo Co., Ltd.) to prepare Carbon Nanotube Dispersion Liquid 1.

[0048] [Preparation Example 2] Carbon Nanotube Dispersion Liquid 2 Carbon Nanotube Dispersion Liquid 2 was prepared in the same manner as Preparation Example 1, except that the composition was changed to 0.0015% by mass of carbon nanotubes and 9.9985% by mass of polycarbonate resin as shown in the composition in Table 1.

[0049] [Preparation Example 3] Carbon Nanotube Dispersion Liquid 3 Carbon Nanotube Dispersion Liquid 3 was prepared in the same manner as Preparation Example 1, except that the composition was changed to 0.001% by mass of carbon nanotubes and 9.999% by mass of polycarbonate resin as shown in the composition in Table 1.

[0050] [Preparation Example 4] Carbon Nanotube Dispersion Liquid 4 As in the composition shown in Table 1, except that the carbon nanotubes were changed to 0.005% by mass and the polycarbonate resin was changed to 9.995% by mass, it was carried out in the same manner as in Preparation Example 1 to prepare a carbon nanotube dispersion liquid 4.

[0051] [Preparation Example 5] Carbon Nanotube Dispersion Liquid 5 As in the composition shown in Table 1, except that the carbon nanotubes were changed to 0.0025% by mass and the polymethyl methacrylate resin was changed to 9.9975% by mass, it was carried out in the same manner as in Preparation Example 1 to prepare a carbon nanotube dispersion liquid 5.

[0052] [Preparation Example 6] Carbon Black Dispersion Liquid As in the composition shown in Table 1, except that the carbon black was changed to 0.0025% by mass and the polycarbonate resin was changed to 9.9975% by mass, it was carried out in the same manner as in Preparation Example 1 to prepare a carbon black dispersion liquid.

[0053]

Table 1

[0054] [Example 1] (A) As a thermoplastic resin substrate, a PC resin substrate, and the carbon nanotube dispersion liquid 1 obtained in Preparation Example 1 were applied using an applicator (experimental apparatus coater 3 , manufactured by Imoto Seisakusho Co., Ltd.) so as to be uniformly coated on the PC resin substrate so that the thickness of the antistatic layer (B) became 10 μm after the drying process. The drying process was carried out at 50°C for 1 hour and at 70°C for 1 hour while gradually increasing the temperature conditions so that no bubbles were generated between the coating film and the substrate to remove the solvent, and the antistatic layer (B) was formed to obtain the resin composite material of the present invention. The solid content concentrations of (b1) carbon nanotubes and (b2) polycarbonate resin in the antistatic layer after the drying process are as shown in Table 2. Further, the evaluation results of the obtained resin composite material are shown in Table 2.

[0055] [Examples 2 and 3] Except that the antistatic layer after the drying process was 5 μm (Example 2) and 2.5 μm (Example 3), the carbon nanotube dispersion liquid 1 was applied onto the PC resin substrate in the same manner as in Example 1 to obtain a resin composite. Table 2 shows the solid content concentrations of (b1) carbon nanotubes and (b2) polycarbonate resin in the antistatic layer after drying and the evaluation results of the resin composite.

[0056] [Example 4] Except that the carbon nanotube dispersion liquid 1 used in Example 1 was changed to the carbon nanotube dispersion liquid 2, the procedure was the same as in Example 1 to obtain a resin composite. Table 2 shows the solid content concentrations of (b1) carbon nanotubes and (b2) polycarbonate resin in the antistatic layer after drying and the evaluation results of the resin composite.

[0057] [Examples 5, 6] Except that the carbon nanotube dispersion liquid 2 was applied onto the PC resin substrate such that the antistatic layer after the drying process was 5 μm (Example 5) and 2.5 μm (Example 6), the procedure was the same as in Example 1 to obtain a resin composite. Table 2 shows the solid content concentrations of (b1) carbon nanotubes and (b2) polycarbonate resin in the antistatic layer after drying and the evaluation results of the resin composite.

[0058] [Example 7] Except that the carbon nanotube dispersion liquid 1 used in Example 1 was changed to the carbon nanotube dispersion liquid 3, the procedure was the same as in Example 1 to obtain a resin composite. Table 2 shows the solid content concentrations of (b1) carbon nanotubes and (b2) polycarbonate resin in the antistatic layer after drying and the evaluation results of the resin composite.

[0059] [Examples 8, 9] Except that the carbon nanotube dispersion liquid 3 was applied onto the PC resin substrate such that the antistatic layer after the drying process was 5 μm (Example 8) and 2.5 μm (Example 9), the procedure was the same as in Example 1 to obtain a resin composite. Table 2 shows the solid content concentrations of (b1) carbon nanotubes and (b2) polycarbonate resin in the antistatic layer after drying and the evaluation results of the resin composite.

[0060] [Examples 10 and 11] The carbon nanotube dispersion liquid 1 used in Example 1 was changed to carbon nanotube dispersion liquid 4, and the carbon nanotube dispersion liquid 4 was applied onto the PC resin substrate in such a manner that the antistatic layer after the drying process was 5 μm (Example 10) and 2.5 μm (Example 11). Otherwise, it was carried out in the same manner as in Example 1 to obtain a resin composite material. Table 2 shows the solid content concentrations of (b1) carbon nanotubes and (b2) polycarbonate resin in the antistatic layer after drying and the evaluation results of the resin composite material.

[0061] [Example 12] The PC resin substrate used in Example 1 was changed to a PMMA resin substrate, and otherwise, it was carried out in the same manner as in Example 1 to obtain a resin composite material. Table 2 shows the solid content concentrations of (b1) carbon nanotubes and (b2) polycarbonate resin in the antistatic layer after drying and the evaluation results of the resin composite material.

[0062] [Comparative Example 1] The carbon nanotube dispersion liquid 1 used in Example 1 was changed to carbon nanotube dispersion liquid 4, and the carbon nanotube dispersion liquid 4 was applied onto the PC resin substrate in such a manner that the thickness of the antistatic layer after drying was 10 μm. Otherwise, it was carried out in the same manner as in Example 1. Table 3 shows the solid content concentrations of (b1) carbon nanotubes and (b2) polycarbonate resin in the antistatic layer after drying and the evaluation results of the resin composite material.

[0063] [Comparative Example 2] The carbon nanotube dispersion liquid 1 used in Example 1 was changed to carbon nanotube dispersion liquid 5, and otherwise, it was carried out in the same manner as in Example 1 to obtain a resin composite material. Table 3 shows the solid content concentrations of (b1) carbon nanotubes and (b2) polymethyl methacrylate resin in the antistatic layer after drying and the evaluation results of the resin composite material.

[0064] [Comparative Example 3] A resin composite material was obtained in the same manner as in Example 1, except that the carbon nanotube dispersion liquid 1 used in Example 1 was changed to a carbon black dispersion liquid. Table 3 shows the solid content concentrations of (b1) carbon black and (b2) polycarbonate resin in the antistatic layer after drying and the evaluation results of the resin composite material.

[0065]

Table 2

[0066]

Table 3

[0067] From the results of Tables 2 and 3, it was suggested that if the carbon nanotube concentration and the coating film thickness are appropriate, antistatic properties and transparency can be achieved simultaneously, and the present invention can be sufficiently applied to applications where both transparency and antistatic properties are required. Also, as in Examples 1 to 11, it was expected that good conductivity and transparency could be obtained when (b2) polycarbonate resin of the (B) antistatic layer and (A) thermoplastic resin substrate are made of the same material. However, comparing Example 12 with Comparative Example 2, contrary to the expectation, it was found that conductivity cannot be exhibited unless the resin used for the antistatic layer is not polycarbonate resin.

Industrial Applicability

[0068] Since the resin composite material of the present invention has sufficient conductivity and transparency, it can be widely used in applications where both antistatic properties and transparency are required.

Claims

A manufacturing method for obtaining a resin composite material provided with an antistatic layer (B) on a thermoplastic resin substrate (A), a step of preparing a carbon nanotube dispersion liquid containing at least (b1) carbon nanotubes, (b2) a polycarbonate resin, and (b3) a polar solvent; a step of applying the carbon nanotube dispersion liquid onto the (A) thermoplastic resin substrate; comprising a step of drying the carbon nanotube dispersion liquid applied onto the (A) thermoplastic resin substrate to form the (B) antistatic layer, wherein the surface resistance value of the resin composite material is 1×10^7 Ω / sq. to less than 1×10^13 Ω / sq., and moreover, the total light transmittance in the visible light region is 80% or more, and the resin composite material is such that, in the (B) antistatic layer, the concentration of the (b1) carbon nanotubes is 0.005% by mass to 0.1% by mass. A manufacturing method for a resin composite material.

2. The manufacturing method for a resin composite material according to Claim 1, wherein in the step of preparing the carbon nanotube dispersion liquid, the concentration of the (b3) polar solvent is 80 to 99% by mass with respect to the total composition of the carbon nanotube dispersion liquid.

3. The manufacturing method for a resin composite material according to Claim 1, wherein the (b3) polar solvent is at least one selected from the group consisting of a halogen-based solvent, an ether-based solvent, a ketone-based solvent, an amine-based solvent, an amide-based solvent, a nitro-based solvent, and an aromatic hydrocarbon-based solvent.

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