JP2018177862A - Conductive resin composition, powdery mixture, method for producing conductive resin composition, and molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive resin composition which can obtain target conductivity with a smaller amount of carbon nanotube to be added and can obtain a cured product excellent in mechanical strength, a powdery mixture, a method for producing a conductive resin composition, and a molded body made from a conductive resin composition.SOLUTION: A conductive resin composition contains (A) carbon nanotube, (B) copolymer polyamide having a melt temperature measured by differential scan thermal analysis of 65-145°C and a melt volume flow rate of 10-200 cm/10 min, (C) a polyamide resin (excluding component (B)), where an amount of the component (A) to be blended is 0.5-20 mass% with respect to 100 mass% of the total of the components (A) to (C), and an amount of the component (B) to be blended is 0.3-2 times the amount of the component (A) to be blended.SELECTED DRAWING: None

Description

  The present invention relates to a conductive resin composition comprising a carbon nanotube, a copolyamide, and a thermoplastic resin containing a polyamide resin, a powdery mixture, a method for producing the conductive resin composition, and a molded article comprising the conductive resin.

  A conductive material to which conductivity is imparted by adding a carbon material to a thermoplastic resin, and a resin product using the conductive material are widely used. Among these carbon materials, it is well known that carbon nanotubes can achieve conductivity at a low content because they have a smaller tube diameter (or fiber diameter) and a larger aspect ratio than other carbon materials.

  However, carbon nanotubes provided as a raw material are often provided as pill-like aggregates. Therefore, in order to conduct electricity in the resin using carbon nanotubes, it is required that the resin be well dispersed in the product resin.

  The reason why carbon black and graphite are often used as conductive materials to be added to resins in the past is that the control of dispersion is easier as compared to carbon nanotubes. Here, with regard to the conductive resin composition using carbon nanotubes, controlling the dispersion of carbon nanotubes in the resin has become a major issue.

  When carbon nanotubes are added to a resin as a conductive additive, in order to maintain the desired physical properties of the resin, it is possible to efficiently express conductivity with the carbon nanotubes as small as possible. The purpose is to control the dispersion of carbon nanotubes. Of course, carbon nanotubes are more expensive than other conductive aids such as carbon black, and the control of the dispersion of carbon nanotubes in the resin also helps to reduce the cost of the conductive resin composition.

  First, a method of producing a pre-composite characterized by bringing carbon nanotubes into contact with at least one plasticizer, and the dispersibility of carbon nanotubes in a polymer by mixing the obtained pre-composite and a polymer material, Improvements in mechanical properties, electrical conductivity, or thermal conductivity have been proposed (claims of Patent Document 1, etc.).

  Next, carbon nanotubes are mixed with a propylene-olefin copolymer wax to form a masterbatch, which is a thermoplastic polycondensate, styrene polymer, polyamide, polyester, polycarbonate, polyacrylate, polyacrylate copolymer, polyacetal, polyolefin, polyolefin copolymer and A conductive material obtained by mixing with an organic polymer selected from the group consisting of a mixture of those substances has been proposed (claims of Patent Document 2, etc.).

  Also disclosed is a method for producing a conductive thermoplastic composition prepared by melt mixing of a thermoplastic resin and a carbon nanotube masterbatch in wax having a melting point of about 45 to about 150 ° C. The masterbatch is said to be more easily prepared than carbon nanotube masterbatch in conventional high molecular weight polymers (claims of Patent Document 3, paragraph 0006, etc.). Furthermore, a method of also improving the melt flow characteristics of the conductive thermoplastic composition by using a carbon nanotube masterbatch in wax is also desirable here, and the thermoplastic resin may be polyester, poly (vinyl chloride), polystyrene, Rubber-modified polystyrene, polyolefin, polycarbonate, polyimide, polyetherimide, poly (ether ketone), poly (ether ether ketone), polysulfone, poly (arylene ether), poly (phenylene sulfide), polyamide, copolymer of styrene and acrylonitrile, copolymers of α-methylstyrene and acrylonitrile, copolymers of acrylonitrile, butadiene and styrene, copolymers of acrylonitrile and styrene and acrylate esters, polyacetals, It is selected from the group consisting of thermoplastic polyurethane, and combinations thereof (the 0001 paragraph of Patent Document 3, claim 11, or the like).

  The present inventor uses a resin composition containing an olefin polymer satisfying the following (1) to (3) and a thermoplastic resin, and a high conductive resin composition having a volume resistivity of 100 Ω · cm or less in the thickness direction. is suggesting. This conductive resin composition contains 15 to 40% by mass of carbon nanotubes, and the olefin polymer has (1) weight average molecular weight (Mw) of 35,000 to 150,000, (2) molecular weight distribution ((2) Mw / Mn) is 3 or less, and (3) the softening point is 80 to 130 ° C. (claim 1 of Patent Document 4).

JP 2008-290936 A Japanese Patent Application Publication No. 2012-507587 Japanese Patent Application Publication No. 2014-511908 JP, 2016-41806, A

  With respect to a conductive resin composition comprising a thermoplastic resin containing a polyamide resin having carbon nanotubes as a conductive additive, carbon less than the conductive resin composition using an olefin polymer disclosed in Patent Document 4 Conductivity at the added amount of nanotubes has been required.

  In addition, a conductive resin composition comprising a thermoplastic resin containing a polyamide resin containing carbon nanotubes as a conductive additive is excellent in high temperature suitability and is expected to be superior to a conductive resin composition comprising a general-purpose polyolefin resin. Is also an area in which

  The present invention has been made in view of such circumstances, and it is possible to obtain the desired conductivity with a smaller amount of added carbon nanotubes, and to obtain a conductive resin which is excellent in mechanical properties and the like. It is an object of the present invention to provide a composition, a powdery mixture, a method for producing a conductive resin composition, and a molded product comprising the conductive resin composition.

  The inventor of the present invention can obtain a conductive resin composition comprising a thermoplastic resin containing a polyamide resin which solves the above-mentioned problems by utilizing a copolyamide having specific physical properties for controlling dispersion of carbon nanotubes. I found out.

That is, the present invention provides the following [1] to [7].
[1] (A) carbon nanotube,
(B) The melting temperature measured by differential scanning calorimetry is 65 to 145 ° C.,
And melt volume flow rate, copolymerized polyamide is 10 to 200 cm ³ / 10min, and (C) a thermoplastic resin containing a polyamide resin (except for component (B))
Including
The blending amount of the component (A) is 0.5 to 20% by mass with respect to a total of 100% by mass of the components (A) to (C), and the blending amount of the component (B) is the component (A) The conductive resin composition characterized in that it is 0.3 to 2 times the compounding amount of
[2] Further, (D) a nonconductive inorganic filler,
The blending amount of the component (A) is 0.5 to 15% by mass with respect to a total of 100% by mass of (A) to (C),
And the conductive resin composition of the said [1] description whose compounding quantity of (D) component is 5-40 mass% with respect to a total of 100 mass% of (A)-(D).
[3] The polyamide resin of component (C) is polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 6 T, polyamide 6 I, polyamide 9 T, polyamide M5 T, polyamide 1010, polyamide 1012, polyamide 10 T The conductive resin composition according to the above [1] or [2], which is at least one selected from the group consisting of: and polyamide MXD6.
[4] (A) carbon nanotube, and (B) melting temperature measured by differential scanning calorimetry is 65 to 145 ° C.,
And melt volume flow rate comprises a copolymerized polyamide is 10 to 200 cm ³ / 10min,
The compounding amount of the component (B) is 0.3 to 2 times the compounding amount of the component (A), and the components (A) and (B) are stirred at a temperature of 65 ° C. or more and a stirring speed of 300 rpm or more Powdery mixture obtained.
[5] Stirring the (A) component and the (B) component at a temperature of 65 ° C. or more and a stirring speed of 300 rpm or more to obtain a powdery mixture,
The method for producing a conductive resin composition according to the above [1] or [3], which comprises, in this order, the step of obtaining the conductive resin composition by adding the component (C) to the powdery mixture.
[6] Stirring the (A) component and the (B) component at a temperature of 65 ° C. or more and a stirring speed of 300 rpm or more to obtain a powdery mixture,
Production of the conductive resin composition according to the above [2] or [3], which comprises, in order, the step of adding the component (C) and the component (D) to the powdery mixture to obtain the conductive resin composition Method.
[7] A molded article comprising the conductive resin composition according to any one of the above [1] to [3], or the conductive resin composition containing the powdery mixture according to the above [4].

  According to the invention [1], it is possible to provide a conductive resin composition which can obtain a cured product excellent in conductivity and mechanical physical properties. According to the invention [4], it is also possible to provide a powdery mixture comprising carbon nanotubes and a copolyamide used in the conductive resin composition. According to this invention [5], the manufacturing method of the conductive resin composition which can obtain the hardened | cured material excellent in electroconductivity and mechanical physical properties can be provided. According to this invention [7], the molded object which consists of an electroconductive resin composition can be provided.

  Hereinafter, embodiments of the present invention will be described.

<Conductive resin composition>
The conductive resin composition of the present invention is
(A) carbon nanotubes,
(B) The melting temperature measured by differential scanning calorimetry is 65 to 145 ° C.,
And melt volume flow rate, copolymerized polyamide is 10 to 200 cm ³ / 10min, and (C) a thermoplastic resin containing a polyamide resin (except for component (B))
Including
The blending amount of the component (A) is 0.5 to 20% by mass with respect to a total of 100% by mass of the components (A) to (C), and the blending amount of the component (B) is the component (A) It is characterized in that it is 0.3 to 2 times the compounding amount of

  The conductive resin composition of the present invention contains at least three components of (A) component, (B) component and (C) component. The content ratio of the component (A), the component (B) and the component (C) affects the conductivity and mechanical properties, so the content of the above three components is adjusted in order to balance them.

[(A) carbon nanotube]
The carbon nanotube of the component (A) used in the present invention is a cylindrical hollow fiber-like substance made of carbon, and the structure may be a single layer or multiple layers, but it is easy to disperse. From the viewpoint, multilayer ones are preferable.

  The carbon nanotube of the component (A) is not particularly limited, and any commercially available product may be used, but the average diameter (average thickness) is 5 to 20 nm, and the average length is about 0.5 to 50 μm. Are preferred and easy to use. If the average diameter of the carbon nanotube is 5 nm or more, the carbon nanotube can be hardly cut during kneading, and if it is 20 nm or less, the conductivity can be enhanced. If the average length of the carbon nanotubes is 0.5 μm or more, the conductivity can be enhanced, and if the average length is 50 μm or less, viscosity increase during kneading can be suppressed, and kneading and molding can be facilitated. Further, from the above viewpoint, the average diameter of the carbon nanotubes is more preferably 6 to 20 nm, still more preferably 7 to 20 nm, and the average length is more preferably 0.5 to 30 μm, still more preferably 0.6 to It is 15 μm. The average major axis and the average length can be determined by observing carbon nanotubes with an electron microscope (SEM, TEM) and performing arithmetic mean (n = 50).

  Moreover, as a carbon nanotube which is (A) component, a well-known carbon nanotube can be used. Examples of commercially available products include multi-walled carbon nanotubes such as Flo Tube 9000 from C-Nano Technology, C-100 from Arkema, and NC 7000 from Nanocyl. These commercially available products satisfy the above-mentioned average major axis and average length, and can be preferably used. It is also excellent in terms of starting mass production and price competitiveness.

  The carbon nanotube which is the component (A) can be produced by an arc discharge method, a chemical vapor deposition method (CVD method), a laser ablation method or the like.

[(B) Copolymerized polyamide]
The copolymerized polyamide of the component (B) used in the present invention has (1) a melting temperature measured by differential scanning calorimetry (DSC) of 65 to 145 ° C. (based on ISO 11357), and (2) melt volume flow rate Is 10 to 200 ml / 10 min (according to ISO 1133, measured at 160 ° C./2.16 kg load).

  As a copolymerization monomer of copolymerization polyamide which is (B) component, 2 or more types of monomers chosen from a lactam, an amino acid, dicarboxylic acid, and diamine are mentioned.

  Moreover, a polyether soft segment can also be used as a copolymerization monomer of (B) component.

  Specific examples of the copolymerization monomer of the copolyamide of component (B) include caprolactam, undecalactam and lauryl lactam in the case of lactam and amino acid, and adipic acid, azelaic acid and sebacine in the case of dicarboxylic acid. When the acid, lauric acid, isophthalic acid, terephthalic acid and dimer acid are diamines, examples include hexamethylene diamine, saberin diamine, phthal diamine and xylene diamine. These choices are made by focusing on the melt temperature and melt volume flow rate. Also, two or more kinds of copolymerized polyamides having different melting temperatures can be selected and used. Similarly, two or more kinds of copolymerized polyamides having different melt volume flow rates can be selected and used.

  Polyether soft segments include polytetramethylene glycol.

  Moreover, the melting temperature measured by differential scanning calorimetry of the copolymerized polyamide of the component (B) is 65 to 145 ° C. (measured according to ISO 11357), thereby using the copolymerized polyamide, the component (A) The dispersibility of the above can be improved and the processing temperature can be lowered. The dispersibility of the component (A) can be improved, and the melting temperature is preferably 70 to 140 ° C., more preferably 70 to 135 ° C. from the viewpoint of lowering the processing temperature.

  In addition, the melt volume flow rate of the copolymerized polyamide of the component (B) is 10 to 200 ml / 10 min (measured in accordance with ISO 1133 and measured at 160 ° C./2.16 kg load) by using the copolymerized polyamide, The dispersibility of the component (A) can be improved, and the influence of the decrease in the melt volume flow rate of the conductive resin composition caused by the addition of the component (A) can be reduced. The melt volume flow rate is preferably 10 to 180 ml / 10 min, more preferably 15 to 170 ml / 10 min.

[(C) Thermoplastic resin containing polyamide resin]
The polyamide resin in the thermoplastic resin of component (C) used in the present invention includes polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 6 T, polyamide 6 I, polyamide 9 T, polyamide M5 T, polyamide At least one selected from 1010, polyamide 1012, polyamide 10T and polyamide MXD 6 is preferred.

  The thermoplastic resin containing the polyamide resin of the component (C) used in the present invention may be composed only of a polyamide resin, but a polymer alloy containing a polyamide resin is also included. Examples of the resin that forms an alloy with the polyamide resin include polyethylene resin, polypropylene resin, polyolefin elastomer resin, ABS resin, polycarbonate resin, polyphenylene ether resin, and polyarylate resin. A compatibilizer may also be included to form a polymer alloy.

  Moreover, the thermoplastic resin containing the polyamide resin of (C) component used by this invention also contains the block copolymer containing a polyamide resin component. Examples of block copolymers containing a polyamide resin component include polyether diols and polyamide elastomers which are block copolymers using polyester diols. Specifically, polytetramethylene ether glycol, polyoxypropylene glycol and the like can be mentioned.

  The content of the component (A) is 0.5 to 20% by mass, preferably 1 to 18% by mass, more preferably 1.5 based on a total of 100% by mass of the components (A) to (C). It is -15 mass%. If the content of the component (A) is less than 0.5% by mass, conductivity may not be exhibited. Moreover, when content of (A) component exceeds 20 mass%, although electroconductivity will become high, there exists a possibility that a conductive resin composition may become hard and a mechanical characteristic may be inferior.

  The content of the component (B) is 0.3 to 2 times by mass the content of the component (A), preferably 0.4 to 1.8 times by mass, more preferably 0.5 to 1.5 mass It is a double. If the content of the component (B) is less than 0.3 times, the dispersibility of the component (A) may be deteriorated, and the conductivity may be reduced. When the content of the component (B) exceeds twice the mass, the molded article tends to be soft.

  In addition, content of (C) component becomes the remainder which deducted content of (A) component and (B) component from a total of 100 mass% of (A)-(C) components. Therefore, when the content of the (A) component and the (B) component increases, the content of the (C) component relatively decreases. The higher the content of the component (C), the easier it is for the resin to exhibit its original characteristics. Therefore, it is judged that the content of the component (C) is good within the range where the conductivity can be satisfied.

  The conductive resin composition of the present invention further comprises (D) a non-conductive inorganic filler, and the compounding amount of the component (A) is 0 with respect to 100% by mass of the total amount of (A) to (C). It is preferable that it is 5-15 mass%, and the compounding quantity of (D) component is 5-40 mass% with respect to 100 mass% of total amounts of (A)-(D) component.

  When the component (D) is contained, the content ratio of the component (A), the component (B), the component (C) and the component (D) affects the conductivity and mechanical properties, so that the balance between them Adjust the content of the above four components to take

[(D) non-conductive inorganic filler]
Examples of the nonconductive inorganic filler of the component (D) used in the present invention include calcium carbonate, precipitated barium sulfate, talc, diatomaceous earth, mica, glass flakes, alumina, magnesium carbonate, calcium sulfate and the like. it can. Among them, addition technology to the resin is established, and calcium carbonate, precipitated barium sulfate and talc, which are competitive in price, can be preferably used.
These nonconductive inorganic fillers may be subjected to surface treatment for the purpose of improving the dispersibility in the resin.
These may be used alone or in combination of two or more.

The average particle diameter of the component (D) is preferably 0.3 to 50 μm, more preferably 0.5 to 20 μm, and still more preferably 0.5 to 10 μm, from the viewpoint of ease of addition.
In the present invention, the average particle diameter means 50% average particle diameter, and can be determined using, for example, Microtrac particle size analyzer (dynamic light scattering method) manufactured by Nikkiso Co., Ltd.

  The component (D) is aggregated of the component (A) by collecting the component (A) on the surface of the component (D) while the resin component composed of the component (B) and the component (C) hardens. It is thought that the effect of effectively performing electrical connection between carbon nanotubes can be achieved. Therefore, the compounding quantity of (A) component can be decreased by mix | blending (D) component in a conductive resin composition.

  The content of the component (A) is 0.5 to 15% by mass, preferably 0.7 to 12% by mass, more preferably 1 with respect to a total of 100% by mass of the components (A) to (D). And 10% by mass. If the content of the component (A) is less than 0.5% by mass, conductivity may not be exhibited. Moreover, when content of (A) component exceeds 15 mass%, although electroconductivity will become high, there exists a possibility that a conductive resin composition may become hard and a mechanical characteristic may be inferior.

  As described above, the content of the component (B) is 0.3 to 2 times by mass of the content of the component (A), preferably 0.4 to 1.8 times by mass, more preferably 0.5 to 0.5 It is 1.5 mass times. If the content of the component (B) is less than 0.3 times, the dispersibility of the component (A) may be deteriorated, and the conductivity may be reduced. When the content of the component (B) exceeds twice the mass, the molded article tends to be soft.

  The content of the component (C) is the total of 100% by mass of the components (A) to (D) minus the content of the components (A), (B) and (D). Therefore, when the content of the component (A), the component (B) and the component (D) increases, the content of the component (C) relatively decreases. The higher the content of the component (C), the easier it is to develop the inherent characteristics of the resin, and therefore, it is judged that the content is high within the range where the conductivity can be satisfied.

  The compounding amount of the component (D) is 5 to 40% by mass, preferably 8 to 35% by mass, more preferably 10 to 30% by mass with respect to the total amount 100% by mass of the components (A) to (D). is there. If the amount is less than 5% by mass, the conductivity may be reduced, and if the amount is more than 40% by mass, the conductive resin composition may be hard and brittle.

[Other ingredients]
The conductive resin composition of the present invention, in addition to the above components, a lubricant, an antistatic agent, an ultraviolet light absorber, a pigment, which is generally blended in a composition of this type, to the extent that the effects of the present invention are not inhibited. Additives such as organic fillers can be blended as required.

<Method of producing conductive resin composition>
Next, a method of producing the above-mentioned conductive resin composition will be described.
The method for producing the conductive resin composition of the present invention [1] comprises stirring the component (A) and the component (B) at a temperature of 65 ° C. or more and a stirring speed of 300 rpm or more to obtain a powdery mixture; Is added to component (C) to obtain a conductive resin composition.
In the method for producing the conductive resin composition of the present invention [2], the powdery mixture is obtained by stirring the components (A) and (B) at a temperature of 65 ° C. or more and a stirring speed of 300 rpm or more. Mixture is added to the (C) component and the (D) component to obtain a conductive resin composition.

  As the component (A) and the component (B), those described above in the section <Conductive resin composition> can be used.

  The component (A) and the component (B) are charged into a mixer, and by stirring and mixing at a high speed of 300 rpm or more at a temperature above the temperature at which the component (B) melts, that is, 65 ° C., (A) The component is loosened and the component (B) adheres to the surface of the component (A). Thus, when component (B) adheres to the surface of component (A), component (A) easily mixes with component (C) when melt-kneading with component (C), (A High concentration and high dispersion to the component (C).

When components (A) and (B) are charged into a mixer and the components are stirred and mixed at a high speed of 300 rpm or more at temperatures higher than the temperature at which component (B) melts, that is, 65 ° C., (B) In order to prevent the components from adhering to the inner wall of the mixer or the stirring blade, the component (B) may be divided and added in two or more portions.

  When two or more types of (B) components having different melting temperatures are used, it is preferable to add one having a low melting temperature first and one having a high melting temperature later.

  The stirring temperature is preferably 70 to 140 ° C., more preferably 70 to 135 ° C., and the stirring speed is preferably 400 to 3000 rpm, more preferably 500 to 2500 rpm. The stirring time is not particularly limited as long as (A) component and (B) component are sufficiently stirred and mixed, but preferably 5 minutes to 24 hours, more preferably 10 minutes to 12 hours.

  As a mixer for stirring and mixing, for example, known high-speed stirring mixers such as dissolvers, butterfly mixers, paddle blade mixers, Henschel mixers, super mixers, Banbury mixers, kneaders and trimixes can be used. Specifically, an FM mixer manufactured by Nippon Coke Industry Co., Ltd., a super mixer manufactured by Kawata Co., Ltd., and the like can be mentioned.

  Next, in the case of the present invention [1], when the component (D) is not contained, the obtained powdery mixture is added to the component (C) and mixed. When the component (D) of the present invention [2] is contained, the obtained powdery mixture is added to the components (C) and (D) and mixed. As the (C) component and the (D) component, those described in the above <Conductive resin composition> can be used.

  The powdery mixture and component (C) or component (C) and component (D) are mixed using a mixer such as a dissolver, butterfly mixer, paddle blade mixer, Henschel mixer, super mixer, or the like. Specifically, a Nauta mixer manufactured by Hosokawa Micron Corporation, a V-type mixer manufactured by Nishimura Machinery Co., Ltd., a ribbon mixer, and the like can be used. If the amount is small, put each component and air in a suitable polyethylene bag and shake it vertically and horizontally.

  Next, the above mixture (mixture of powdery mixture and component (C) or component (C) or component (D)) is melt-kneaded with a twin-screw extruder and further extruded into strands, and then formed into pellets. Granulate to obtain a conductive resin composition. The heating temperature at the time of melt-kneading is preferably 150 to 600 ° C., more preferably 200 to 500 ° C.

  According to the manufacturing method, the carbon nanotubes of the component (A) can be highly dispersed in the resin, so that the target conductivity can be obtained with a small amount of carbon nanotubes added. Therefore, by using carbon nanotubes, a conductive resin composition capable of forming a cured product excellent in moldability, mechanical properties and the like can be obtained. Further, the manufacturing method is a simple and cost-effective method.

<Powder-like mixture>
The powdery mixture of the present invention has a melting temperature of 65 to 145 ° C. as measured by (A) carbon nanotubes, and (B) differential scanning calorimetry.
And melt volume flow rate comprises a copolymerized polyamide is 10 to 200 cm ³ / 10min,
The compounding amount of the component (B) is 0.3 to 2 times the compounding amount of the component (A), and the components (A) and (B) are stirred at a temperature of 65 ° C. or more and a stirring speed of 300 rpm or more It is a powdery mixture obtained.

  This powdery mixture is obtained by coating the surface of the component (A) with the component (B). Therefore, compared with the carbon nanotube which is (A) component, since there are few fine powders of 1 micrometer or less, it is excellent in handling nature.

  Further, by coating the surface of the component (A) with the component (B), the powdery mixture of the present invention can be uniformly blended with the thermoplastic resin of the component (C). Therefore, the conductive resin composition containing this powdery mixture has conductivity at a small addition amount, and can form a cured product excellent in mechanical properties.

  The content of the component (B) is 0.3 to 2 times by mass the content of the component (A), preferably 0.4 to 1.8 times by mass, more preferably 0.5 to 1.5 mass It is a double. If the content of the component (B) is less than 0.3 times, the dispersibility of the component (A) may be deteriorated, and the conductivity may be reduced. When the content of the component (B) exceeds twice the mass, the molded article tends to be soft.

  In addition, the said (A) component and (B) component are as having demonstrated in the term of <conductive resin composition>.

<Molded body>
The molded body of the present invention is composed of the above-mentioned conductive resin composition or the above-mentioned powdery mixture. The molding method is not particularly limited, and various molding methods generally adopted for thermoplastic resins can be applied. For example, an injection molding method, an extrusion molding method, a calendar molding method, a press molding method and the like can be mentioned.

  Hereinafter, the present invention will be specifically described by way of examples and comparative examples. The following examples are presented to explain the present invention in detail, and the present invention is not limited to the following examples as long as the gist of the present invention is not violated.

[Preparation of bending test and Izod impact test sample]
A bending test and an Izod impact test sample were prepared using an injection molding machine (manufactured by Toshiba Machine Co., Ltd., IS80EPN-2A) and a test piece molding die (clamping force: 80 t) in accordance with JIS K6911. The cylinder temperatures at the time of molding are shown in Tables 2 and 3.

[Evaluation of physical properties]
(1) Measurement of Volume Resistivity For sample preparation by injection molding, a plate of 13 mm long × 180 mm wide and about 3 mm thick was manufactured using an injection molding machine. A volume resistivity was calculated by applying 90 volts with a resistance measurement function of a resistivity meter (Loresta GPMCP-T610 type, manufactured by Mitsubishi Chemical Analytech Co., Ltd.).

(2) Bending test According to JIS K7203, the bending elastic modulus was measured by a precision universal testing machine (manufactured by Shimadzu Corporation, AGS-500A type).

(3) Izod impact strength (IZOD)
The Izod impact strength was measured with a universal pendulum impact tester (manufactured by CEAST, model 6545/000) in accordance with JIS K7111-1.

  Each component used by the Example and the comparative example is as follows.

[Carbon nanotube which is component (A)]
· (A-1): manufactured by Nanocyl, product name: "NC7000" (average diameter: 9.5 nm, average length: 1.5 μm)
· (A-2): Arkema product name: "C-100" (average diameter: 13 nm, average length: 4 μm)

[Copolymerized polyamide as component (B)]
· (B-1): manufactured by EMS-GRIVORY, product name: "Griltex D1666A" (melting temperature: 80 ° C, in accordance with ISO 11357, measured by DSC, melt volume flow rate: 90 ml / 10 min (in accordance with ISO 1133, 160 ° C /) Measured with 2.16 kg load)
· (B-2): manufactured by EMS-GRIVORY, product name: "Griltex 2A" (melting temperature 125 ° C according to ISO 11357, measured by DSC, melt volume flow rate: 18 ml / 10 min (based on ISO 1133, 160 ° C / 2. Measured with 16 kg load)
· (B-3): manufactured by Arkema, product name: "Platamid H1186" (melting temperature 150 ° C according to ISO 11357, measured by DSC, melt volume flow rate: 18 ml / 10 min (based on ISO 1133, 160 ° C / 2.16kg load Measured by

[Thermoplastic resin containing the polyamide resin which is the (C) ingredient]
-(C-1): Ube Industries, Ltd. product name: "Nylon resin injection 1013 B" (PA 6)
・ (C-2): Arkema product name: "Rilsan BMF O" (PA11)
・ (C-3): Mitsubishi Gas Chemical Co., Ltd., Product name: "MX nylon S6007" (PA MXD6)

[Non-Conductive Inorganic Filler as Component (D)]
· (D-1): Nippon Talc Co., Ltd., Product name: "MICRO ACE P-3" (talc) Average particle diameter: 5.0 μm
· (D-2): manufactured by Sakai Chemical Industry Co., Ltd., Product name: "VARIACE B-54" (Settled barium sulfate) Average particle size: 1.2 μm

(Examples 1 to 3, Comparative Examples 1 to 3)
[Production of powdery mixture]
Components (A) and (B) are stirred and mixed in an FM mixer (FM 10 C / I, volume: 9 L) manufactured by Nippon Coke Kogyo Co., Ltd. under the mixing conditions shown in Table 1 and stirring conditions to obtain a powdery mixture Obtained. At this time, the total of the input amounts of the (A) component and the (B) component was made to be 0.7 kg. The stirring temperature was adjusted by introducing steam into the jacket of the FM mixer. However, heating oil was circulated to perform temperature control in order to set the temperature to 160 ° C. only in Comparative Example 3.

  As for the types of materials in Table 1, the components (A-1), (A-2), (B-1) and (B-2) are the scope of the invention [1] and the invention [2]. It is the material inside. Component (B-3) is a material whose melting temperature is outside the scope of the present invention. About the compounding ratio of the material in Table 1, About Examples 1-3 and Comparative Example 3, it exists in the range of this invention [1] and this invention [2], about this Comparative Example 1 and Comparative Example 2, this It is outside the scope of the invention [1] and the present invention [2]. Further, with regard to all stirring temperatures and rotational speeds in Examples 1 to 3 and Comparative Examples 1 to 3, the conditions within the scope of claims of the present invention [1], the present invention [2] and the present invention [4] Was used. Moreover, stirring time was made into 1 to 2 hours.

  Further, the bulk density of the carbon nanotube simple substance and the powdery mixture was measured according to JIS K 5101 and is shown in Table 1. The bulk density of all the powdery mixtures of Examples 1 to 3 and Comparative Examples 1 to 3 is 0.2 g / ml or more, and is not soft compared to carbon nanotubes alone, so it becomes easy to handle. There is.

(Examples 4-8, comparative examples 5-7)
Dry blending of the powdery mixture of Examples 1 to 3 and Comparative Examples 1 to 3 and the mixture of Component (C) or Component (C) and Component (D), and then twin-screw extruder (Toshiba Kikai Co., Ltd.) And melt-kneaded with TEM-35B (screw diameter: 35 mm, L / D: 32, vent type), and further attach a die with a strand extraction hole of 3 mm in diameter at the outlet of the twin-screw kneader, The kneaded material was extruded from the above, placed in a water tank, cooled, and then pelletized with a strand cutter. Using this pellet, a sample for physical property measurement was produced by injection molding, and the physical property was measured.

(Comparative example 4)
For Comparative Example 4, dry blending of (A) component, (B) component and (C) component is carried out without making a powdery mixture of (A) component and (B) component, and then a twin-screw extruder ( Melt and knead with Toshiba Machine Co., Ltd., TEM-35B (screw diameter: 35 mm, L / D: 32, vent type), and further, a die with a strand extraction hole of 3 mm in diameter at the outlet of the twin screw kneader After mounting, the kneaded material was extruded from the die, placed in a water tank, cooled, and pelletized with a strand cutter. Using this pellet, a sample for physical property measurement was produced by injection molding, and the physical property was measured.

  Tables 2 and 3 show the compounding ratio of the materials, the kneading and molding conditions, and the physical property evaluation results. In addition, the blank in Table 2 and Table 3 represents no blending.

  A comparison of Example 6 with the production of the powdery mixture and Comparative Example 4 without the production of the powdery mixture shows that the volume resistivity is much smaller in Example 6 and the flexural modulus and IZOD Impact strength is also great. It is considered that the production of a powdery mixture improves the dispersibility of carbon nanotubes, improves the connection of carbon nanotubes, and facilitates the transfer of electricity. In addition, it is considered that, as the dispersibility is improved, aggregates of carbon nanotubes are also reduced, and the flexural modulus and the IZOD impact strength are improved.

  About the influence of the compounding ratio of the (A) component and the (B) component, comparing Example 4 within the scope of the present invention with Comparative Example 5 in which the compounding ratio of the (B) component is reduced outside the scope of the present invention Example 4 is superior in all of volume resistivity, flexural modulus and IZOD impact strength. It is considered that the dispersion of carbon nanotubes is insufficient because the proportion of the component (B) is small.

  Regarding the influence of the blending ratio of the component (A) and the component (B), comparing Example 6 within the scope of the present invention with Comparative Example 6 in which the blending ratio of the component (B) is increased outside the scope of the present invention, Example 6 is superior in volume resistivity and flexural modulus. It is considered that since the proportion of the component (B) is large, the carbon nanotubes are well dispersed, but the connection between the carbon nanotubes is deteriorated to make it difficult to transmit electricity. Since the component (B) is a soft material, the IZOD impact strength is considered to be larger in Comparative Example 6 in which the amount of the component (B) added is increased. Is judged to be better.

  Comparing Example 5 with Comparative Example 7 using (B-3) in which the melting temperature of the component (B) is out of the range of the present invention, in all of volume resistivity, flexural modulus and IZOD impact strength Example 5 is better. It is considered that if the melting temperature of the component (B) is high, the dispersion of carbon nanotubes will be insufficient. It is believed that the melting temperature of the copolyamide is related to the degree of randomness of copolymerization and affects the dispersibility of carbon nanotubes.

  In Example 7 and Example 8, the component (D) is added. When Example 5 and Example 7 are compared, Example 7 has equivalent volume resistivity even if the addition amount of carbon nanotubes is small. Similarly, when Example 6 and Example 8 are compared, Example 8 has good volume resistivity even if the addition amount of carbon nanotubes is small. Therefore, it is considered to be an effective method to add an appropriate amount of the component (D) while taking into consideration the influence on properties such as flexural modulus and IZOD impact strength.

  Molded articles made of the conductive resin composition containing the polyamide resin of the present invention have good conductivity even with a small amount of addition of carbon nanotubes as compared with carbon black and graphite conventionally used as a conductivity imparting agent. Since the properties are easily obtained, the moldability and mechanical properties of the resin using the conductive resin composition are excellent, and it is suitable for injection molded articles, extrusion molded articles, films and sheets for which antistatic and electromagnetic wave absorption are required. In particular, since the dispersibility of the carbon nanotube which is a conductivity imparting agent is excellent, the application to the automotive outer plate field where surface smoothness performance, antistatic performance, heat resistance and the like are required can be expected.

Claims (7)

(A) carbon nanotubes,
(B) The melting temperature measured by differential scanning calorimetry is 65 to 145 ° C.,
And melt volume flow rate, copolymerized polyamide is 10 to 200 cm ³ / 10min, and (C) a thermoplastic resin containing a polyamide resin (except for component (B))
Including
The blending amount of the component (A) is 0.5 to 20% by mass with respect to a total of 100% by mass of the components (A) to (C), and the blending amount of the component (B) is the component (A) The conductive resin composition characterized in that it is 0.3 to 2 times the compounding amount of Furthermore, (D) contains a nonconductive inorganic filler,
The blending amount of the component (A) is 0.5 to 15% by mass with respect to a total of 100% by mass of (A) to (C),
And the conductive resin composition of Claim 1 whose compounding quantity of (D) component is 5-40 mass% with respect to a total of 100 mass% of (A)-(D).   The polyamide resin of component (C) is polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 6 T, polyamide 6 I, polyamide 9 T, polyamide M5 T, polyamide 1010, polyamide 1012, polyamide 10 T, and polyamide MX D6. The conductive resin composition according to claim 1 or 2, which is at least one selected from the group consisting of (A) carbon nanotubes,
(B) melting temperature measured by differential scanning calorimetry is a sixty-five to one hundred forty-five ° C., and and melt volume flow rate comprises a copolymerized polyamide is 10 to 200 cm ³ / 10min,
The compounding amount of the component (B) is 0.3 to 2 times the compounding amount of the component (A), and the components (A) and (B) are stirred at a temperature of 65 ° C. or more and a stirring speed of 300 rpm or more Powdery mixture obtained. Stirring the (A) component and the (B) component at a temperature of 65 ° C. or more and a stirring speed of 300 rpm or more to obtain a powdery mixture,
The manufacturing method of the conductive resin composition of Claim 1 or 3 including the process of adding (C) component to powdery mixture and obtaining a conductive resin composition in this order. Stirring the (A) component and the (B) component at a temperature of 65 ° C. or more and a stirring speed of 300 rpm or more to obtain a powdery mixture,
The manufacturing method of the conductive resin composition of Claim 2 or 3 including the process of adding a (C) component and a (D) component to a powdery mixture, and obtaining a conductive resin composition in this order.   A molded article comprising the conductive resin composition according to any one of claims 1 to 3 or the powdery mixture according to claim 4.