JP2010196012A - Resin composition - Google Patents

Abstract

Carbon nanotubes are known to have high conductivity when added in small amounts, but it is difficult to develop stable conductivity by injection molding or the like. Provided are a resin composition and a molded product that can stably develop conductivity without improving a mold or the like, and a method for producing the same.
A resin composition comprising a polyolefin-based resin, carbon nanotubes, and an inorganic filler. And a molded article comprising the resin composition. Furthermore, it consists of 25 to 98.5% by weight of polyolefin resin, 0.1 to 25% by weight of multi-walled carbon nanotubes, and 1 to 50% by weight of inorganic filler, which not only increases the concentration of carbon nanotubes in the resin, A resin composition in which carbon nanotubes are prevented from being unevenly distributed during injection molding, and a decrease in surface conductivity of a molded product is suppressed.
[Selection figure] None

Description

The present invention relates to a resin composition in which carbon nanotubes and an inorganic filler are blended, and a molded article exhibiting stable conductivity regardless of a molding method.

Carbon nanotubes have characteristics such as electronics (transistor elements, wiring, etc.), energy (electrode materials for fuel cells, solar power generation devices, gas storage, etc.), electron emission (flat panel devices, etc.), chemistry (adsorbents, catalysts, sensors). Etc.), composite materials (conductive plastics, reinforced materials, flame retardant nanocomposites, etc.) are expected to be applied in various fields. In the future, if mass production of carbon nanotubes progresses and the price becomes cheap, it is expected that the market for conductive (electrostatic) plastic materials will expand in the plastic field. Advantages of using carbon nanotubes include that they are less conductive than carbon black, exhibit conductivity, have less dropout, and have a smooth surface. However, carbon nanotubes have a very large aspect ratio and are very difficult to disperse due to properties such as having no functional groups on the surface. In particular, dispersion in plastic is very difficult. In addition, carbon nanotubes tend to be oriented by giving a strong shear during molding as in injection molding. This resulted in a decrease in conductivity due to a decrease in the presence of carbon nanotubes from the surface of the molded product. Since carbon nanotubes efficiently form a conductive network by highly dispersing a small amount, there is a problem that the influence of orientation is large.

Conventionally, as a technique for improving the conductivity by exposing carbon nanotubes to the surface of an injection molded product, a method of processing an injection mold and controlling the orientation of the carbon nanotubes (see Patent Document 1). In addition, by keeping the mold temperature above the glass transition temperature after injection molding, the distortion during injection molding is suppressed, the carbon nanotubes are moved to the surface, and the crystallization is promoted to move the carbon nanotubes. There is known a method for improving conductivity by applying the method (see Patent Document 2). In addition, as a method of suppressing the decrease in conductivity in injection molding, it is common to increase the amount of conductive filler added, but the apparent amount added by making the conductive filler unevenly distributed without increasing the amount added is Can be raised. As a technique for unevenly distributing the conductive filler, a technique for unevenly distributing the conductive filler to one resin using two or more kinds of resins by utilizing the difference in affinity of the conductive filler to the resin (Patent Document 3, non-patent document 3). Patent Documents 1 and 2).

However, the technique described in Patent Document 1 has a problem that a mold must be made for each molded product, and it cannot cope with a complicated shape. The technique described in Patent Document 2 is not preferable because it requires time for heat retention during molding, resulting in poor productivity, and a longer time for the resin to stay in the molding machine, which may cause deterioration of physical properties. Further, the techniques described in Patent Document 3 and Non-Patent Documents 1 and 2 can stabilize the conductivity of the molded product, but the result is that the conductivity of the resin on the side to be unevenly distributed and the carbon nanotube is poor, but the conductivity is lowered. . In particular, when a polyethylene resin is added to the polypropylene resin, there is a problem that the conductivity is lowered as compared with the case of the polypropylene resin alone. Furthermore, in the case of carbon nanotubes, it is difficult to disperse and there is a need to solve the problem.

JP 2004-107534 A JP 2007-296725 A JP 2008-274060 A

Journal of Japanese Rheological Society, 2004, p. 129 Journal of Japan Rubber Association, 2002, p. 380

An object of the present invention is to provide a resin composition and a molded product that exhibit high conductivity even when carbon nanotubes are blended with low addition, and can exhibit stable conductivity regardless of the molding method. And

That is, the present invention comprises 25 to 98.5% by weight of polyolefin resin, 0.1 to 25% by weight of multi-walled carbon nanotubes, and 1 to 50% by weight of inorganic filler. The inorganic filler not only increases the concentration of carbon nanotubes in the resin. The present invention relates to a resin composition in which carbon nanotubes are prevented from being unevenly distributed due to spiral steps during injection molding, and a decrease in surface conductivity of a molded product is suppressed.

The present invention further relates to a resin composition comprising a polyolefin resin comprising 30 to 100% by weight of a polypropylene resin and 0 to 70% by weight of a polyethylene resin.
Furthermore, the present invention relates to a resin composition characterized in that the inorganic filler has a plate shape and a needle shape.

Further, in the present invention, the inorganic filler having the plate-like and needle-like shapes is talc, mica, hydrotalcite, plate-like calcium carbonate, wollastonite, potassium titanate, acicular magnesium hydroxide, aluminum borate, basic It is related with the resin composition characterized by being 1 or more types chosen from magnesium sulfate.
Furthermore, this invention relates to the molded object which consists of the said resin composition.

According to the present invention, it is possible to obtain a conductive resin composition having good conductivity with low addition, and it is possible to obtain a molded product that retains good conductivity even in an injection molded product using the same.

The carbon nanotube used in the present invention has a shape in which one surface of graphite is wound into a cylindrical shape, and the single-walled carbon nanotube having a structure in which the graphite layer is wound in one layer, two layers or more. Even a multi-walled carbon nanotube wound may be mixed, but a multi-walled carbon nanotube is preferable. Also, carbon nanotubes having an amorphous structure instead of a graphite structure on the side wall of the carbon nanotube may be used.

Furthermore, the shape may be any shape such as a needle shape, a coil shape, a tube shape, or a cup shape. Specific examples include graphite whisker, filamentous carbon, graphite fiber, ultrafine carbon tube, carbon tube, carbon fibril, carbon microtube, and carbon nanofiber. These forms can be used in the form of one or a combination of two or more.

The carbon nanotube of the present invention can be generally produced by a laser ablation method, an arc discharge method, a thermal CVD method, a plasma CVD method, a combustion method or the like, but may be a carbon nanotube produced by any method. In particular, the method of making acetylene as a raw material using zeolite as a catalyst carrier by the thermal CVD method is highly purified and well graphitized multi-layer carbon, although there is an amorphous carbon coating by some thermal decomposition without any purification. It is preferable as a carbon nanotube used in the present invention in that a nanotube is obtained.
The size of the carbon nanotube used in the present invention is not particularly limited, and specific examples include a fiber diameter of 0.5 to 300 nm and a fiber length of 0.01 to 100 μm. A preferred range is 1 to 200 nm as the fiber diameter and 1 to 10 μm as the fiber length.

The shape of the secondary particles of the carbon nanotubes used in the present invention is not particularly limited. For example, the carbon nanotubes, which are general primary particles, may be intricately intertwined. It may be an aggregate. Secondary particles, which are aggregates of linear carbon nanotubes, are preferable because they have better dispersibility than those intertwined.

The carbon nanotube used in the present invention may be a surface-treated carbon nanotube derivative or a carbon nanotube derivative provided with a functional group such as a carboxyl group. In addition, carbon nanocapsules encapsulating metal atoms, fullerenes, and the like can also be used.

In the present invention, as the olefin resin, those having a main component of a single weight body such as ethylene, propylene, butene, or pentene, or a copolymer are used. For example, polyethylene resin, polypropylene resin, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, propylene-vinyl acetate copolymer, Propylene-methyl acrylate copolymer, propylene-methyl methacrylate copolymer, propylene-ethyl acrylate copolymer, polybutene, poly-3-methylbutene-1, poly-4-methylpentene-1, ethylene ionomer resin, etc. It is done. These can be used alone or in admixture of two or more. In the present invention, it is more preferable to use a polypropylene resin or a polyethylene resin.

The polyethylene resin in the present invention is a high density polyethylene, a low density polyethylene, an ultra low density polyethylene, a linear low density polyethylene, an ultra high molecular weight polyethylene, a metallocene (single site) catalyst polyethylene, a cyclic polyethylene, and maleic anhydride Examples thereof include modified polyethylene resins such as modified polyethylene, glycidyl (meth) acrylate modified polyethylene, and 2-hydroxyethyl (meth) acrylate modified polyethylene. In the present invention, it is more preferable to use high-density polyethylene having a high degree of crystallinity in order to keep the conductivity high.

The polypropylene resin in the present invention is a homopolypropylene, block propylene copolymer, random propylene copolymer polyolefin resin, ethylene propylene copolymer rubber, maleic anhydride modified polypropylene, glycidyl (meth) acrylate modified polypropylene, -Modified polypropylene resins such as hydroxyethyl (meth) acrylate-modified polypropylene. Etc. In the present invention, it is particularly preferable to use a homopolypropylene resin that does not contain other components that affect the uneven distribution of carbon nanotubes.

In the present invention, as the olefin resin, it is most preferable to use a polypropylene resin, particularly a homopolypropylene resin, from the viewpoint of developing conductivity. Polypropylene resin has a lower interfacial tension with a carbon-based material than polyethylene-based resin, and forms a conductive network by causing a certain agglomeration. Therefore, conductivity is higher than that of polyethylene-based resin. In addition, since the polypropylene-based resin has higher crystallinity than the polyethylene-based resin, the carbon nanotube is unevenly distributed in the non-crystalline portion to form a conductive network. For the above reasons, it is preferable to use a polypropylene resin rather than a polyethylene resin, and it is most preferable to use a homopolypropylene resin with less ethylene component.

When uniform dispersion is required, it is preferable to use a polyethylene resin. In the case of using a polyethylene resin, it is preferable to use a resin having higher crystallinity. For example, in a low density polyethylene resin and a high density polyethylene resin, it is more preferable to use a high density polyethylene resin having high crystallinity. Further, a polymer alloy of a polypropylene resin and a polyethylene resin exhibits stable conductivity with low addition if carbon nanotubes are unevenly distributed in the polyethylene resin portion in the alloy resin and the dispersed state as the alloy is a continuous system. The alloy system is slightly inferior in conductivity to the case of using polypropylene resin alone, but is less advantageous in terms of stability because of less variation in conductivity. In the polymer alloy system, the polyethylene resin layer in which carbon nanotubes are highly unevenly distributed does not become a continuous layer, which causes a decrease in conductivity.

In addition, even if the polyethylene resin layer is continuous, if the compounding ratio is too large, it is a resin that does not easily exhibit conductivity, so the conductivity is significantly lower than when using a polypropylene resin alone, and there is less merit of alloying. This is not preferable. Therefore, it is necessary to set the blending ratio of the polyethylene resin / polypropylene resin forming the continuous layer, preferably 30 to 70/70 to 30, more preferably 40 to 60/60 to 40. Is good. Among the blending ratios, the polyethylene resin is more preferable than the polypropylene resin because it is advantageous for the expression of conductivity.

A crystal nucleating agent may be added to the olefin resin in the present invention. The grade in which the crystal nucleating agent is added by the resin manufacturer may be used, or the crystal nucleating agent may be added when the resin composition of the present invention is prepared. Addition of a crystal nucleating agent is preferable because the crystallinity of the resin can be increased, and this causes the carbon nanotubes to be unevenly distributed in the non-crystalline portion, thereby forming a conductive network and increasing the conductivity.

Examples of the crystal nucleating agent include polyvalent organic acids and / or metal salts thereof, aryl phosphate compounds, cyclic polyvalent metal aryl phosphate compounds, and dibenzylidene sorbitol compounds. The addition amount of the crystal nucleating agent is preferably 0.01 to 5% by weight in the resin composition. If it is 0.01% by weight or less, a sufficient effect cannot be exhibited, and even if 5% by weight or more is added, no further effect can be expected.

  Examples of polyvalent organic acids and / or metal salts thereof include malonic acid, succinic acid, adipic acid, maleic acid, azelaic acid, sebacic acid, dodecanedioic acid, citric acid, butanetricarboxylic acid, butanetetracarboxylic acid, naphthenic acid, Cyclopentanecarboxylic acid, 1-methylcyclopentanecarboxylic acid, 2-methylcyclopentanecarboxylic acid, cyclopentenecarboxylic acid, cyclohexanecarboxylic acid, 1-methylcyclohexanecarboxylic acid, 4-methylcyclohexanecarboxylic acid, 3,5-dimethylcyclohexanecarboxylic acid Acid, 4-butylcyclohexanecarboxylic acid, 4-octylcyclohexanecarboxylic acid, cyclohexenecarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, benzoic acid, toluic acid, xylic acid, ethylbenzoic acid, 4-t-butyl Carboxylic acid (excluding aliphatic monocarboxylic acid) such as benzoic acid, salicylic acid, phthalic acid, trimellitic acid, phenylphosphonic acid, pyromellitic acid, or lithium, sodium, potassium, magnesium, calcium, strontium, barium And alkali metal such as alkaline earth metal, zinc or aluminum salt.

Examples of the aryl phosphate compound include metal salts of the following compounds.
Bis (4-t-butylphenyl) phosphate, bis (4-cumylphenyl) phosphate, 2,2′-methylene-bis (4,6-di-t-butylphenyl) phosphate, 2,2′-methylene-bis ( 4-cumyl-6-tert-butylphenyl) phosphate, 2,2′-methylene-bis (4-methyl-6-tert-butylphenyl) phosphate, 2,2′-methylene-bis (4-ethyl-6- t-butylphenyl) phosphate, 2,2′-methylene-bis (4,6-di-methylphenyl) phosphate, 2,2′-methylene-bis (4,6-di-ethylphenyl) phosphate, 2,2 '-Ethylidene-bis (4,6-di-t-butylphenyl) phosphate, 2,2'-ethylidene-bis (4-i-propyl-6-t-butylphenyl) phosphate 2,2′-ethylidene-bis (4-s-butyl-6-tert-butylphenyl) phosphate, 2,2′-butylidene-bis (4,6-di-methylphenyl) phosphate, 2,2′-butylidene -Bis (4,6-di-t-butylphenyl) phosphate, 2,2'-t-octylmethylene-bis (4,6-di-methylphenyl) phosphate, 2,2'-t-octylmethylene-bis Alkali metals such as (4,6-di-t-butylphenyl) phosphate, 4,4′-dimethyl-6,6′-di-t-butyl-2,2′-biphenyl) phosphate (eg, lithium, sodium) , Potassium), mono- and bis- (4-tert-butylphenyl) phosphate, dihydrooxy- (4-tert-butylphenyl) phosphate, dihydroxy-bis (4-t Butylphenyl) phosphate, tris (4-t- butylphenyl) aluminum such as phosphates, salts of calcium and zinc.

  Examples of the cyclic polyvalent metal aryl phosphate compound include bis [2,2′-methylene-bis (4,6-di-t-butylphenyl) phosphate], bis [2,2′-methylene-bis (4-methyl-). 6-t-butylphenyl) phosphate], bis [2,2′-thiobis (4-methyl-6-t-butylphenyl) phosphate], bis [2,2′-thiobis (4-ethyl-6-t-) Butylphenyl) phosphate], bis [2,2′-thiobis (4,6-di-t-butylphenyl) phosphate], bis [2,2′-thiobis (4-t-octylphenyl) phosphate], bis [ 2,2′-methylene-bis (4,6-di-t-butylphenyl) phosphate], bis [(4,4′-dimethyl-6,6′-di-t-butyl-2,2′-biphenyl) ) Phosphate], bis [2,2′-ethylidene-bis (4,6-di-t-butylphenyl) phosphate], tris [2,2′-ethylidene-bis (4,6-di-t-butylphenyl) Phosphate], tris [2,2′-methylene-bis (4,6-di-t-butylphenyl) phosphate], dihydroxy-2,2′-methylene-bis (4,6-di-t-butyl) Phenyl) phosphate, dihydrooxy-2,2′-methylene-bis (4-cumyl-6-tert-butylphenyl) phosphate, dihydrooxy-bis [2,2′-methylene-bis (4,6-di-t) -Butylphenyl) phosphate], dihydrooxy-2,2'-methylene-bis (4-methyl-6-tert-butylphenyl) phosphate, dihydrooxy-2,2'-ethyl Den-bis (4,6-di-t-butylphenyl) phosphate, hydroxy-bis [2,2′-methylene-bis (4,6-di-t-butylphenyl) phosphate], hydroxy-bis [2, 2′-methylene-bis (4-cumyl-6-tert-butylphenyl) phosphate], bis [2,2′-methylene-bis (4,6-di-tert-butylphenyl) phosphate], hydroxy-bis [2,2′-methylene-bis (4-methyl-6-tert-butylphenyl) phosphate], hydroxy-bis [2,2′-ethylidene-bis (4,6-di-tert-butylphenyl) phosphate] And alkaline earth metals (for example, calcium and barium), aluminum, titanium, magnesium, zinc, and oxyzirconium salts.

  Examples of the dibenzylidene sorbitol compound include 1,3,2,4-dibenzylidene sorbitol, 1,3-benzylidene-2,4-p-methylbenzylidene sorbitol, and 1,3-benzylidene-2,4-p-ethylbenzylidene sorbitol. 1,3-p-methylbenzylidene-2,4-benzylidene sorbitol, 1,3-p-ethylbenzylidene-2,4-benzylidene sorbitol, 1,3-p-methylbenzylidene-2,4-p-ethylbenzylidene Sorbitol, 1,3-p-ethylbenzylidene-2,4-p-methylbenzylidene sorbitol, 1,3,2,4-bis (p-methylbenzylidene) sorbitol, 1,3,2,4-bis (p- Ethylbenzylidene) sorbitol, 1,3,2,4-bis (pn-propylbenzyl) Den) sorbitol, 1,3,2,4-bis (pi-propylbenzylidene) sorbitol, 1,3,2,4-bis (pn-butylbenzylidene) sorbitol, 1,3,2,4- Bis (ps-butylbenzylidene) sorbitol, 1,3,2,4-bis (pt-butylbenzylidene) sorbitol, 1,3- (2 ', 4'-dimethylbenzylidene) -2,4-benzylidene Sorbitol, 1,3-benzylidene-2,4- (2 ′, 4′-dimethylbenzylidene) sorbitol, 1,3,2,4-bis (2 ′, 4′-dimethylbenzylidene) sorbitol, 1,3,2 4-bis (3 ′, 4′-dimethylbenzylidene) sorbitol, 1,3,2,4-bis (p-methoxybenzylidene) sorbitol, 1,3,2,4-bis (p Ethoxybenzylidene) sorbitol, 1,3-benzylidene-2,4-p-chlorobenzylidene sorbitol, 1,3-p-chlorobenzylidene-2,4-benzylidene sorbitol, 1,3-p-chlorobenzylidene-2,4- p-methylbenzylidene sorbitol, 1,3-p-chlorobenzylidene-2,4-p-ethylbenzylidene sorbitol, 1,3-p-methylbenzylidene-2,4-p-chlorobenzylidene sorbitol, 1,3-p- Examples thereof include ethylbenzylidene-2 · 4-p-chlorobenzylidene sorbitol and 1,3,2,4-bis (p-chlorobenzylidene) sorbitol.

As the inorganic filler used in the present invention, known inorganic materials can be used. Specifically, for example, talc, silica, diatomaceous earth, alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, ferrite, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, Basic magnesium carbonate, light calcium carbonate, heavy calcium carbonate, colloidal calcium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, zeolite, dosonite, hydrotalcite, calcium sulfate, barium sulfate, calcium silicate (wollastonite, zonotlite ), Basic magnesium sulfate, clay, mica, montmorillonite, bentonite, activated clay, sepiolite, imogolite, sericite, glass fiber, glass beads, silica balloon, aluminum nitride, boron nitride, nitriding Lee arsenide, metal powders, potassium titanate, MOS, lead zirconate titanate, aluminum borate, can be used molybdenum sulfide, silicon carbide, stainless steel fiber, zinc borate or the like. These inorganic fillers may be used alone or in combination of two or more. In the present invention, among these, at least one selected from talc, mica, hydrotalcite, plate-like calcium carbonate, wollastonite, potassium titanate, acicular magnesium hydroxide, aluminum borate, and basic magnesium sulfate. It is preferable to use talc.

The shape of the inorganic filler used in the present invention is not particularly limited, and fillers such as a fiber shape, a rod shape, a needle shape, a plate shape, a spherical shape, a balloon shape, a spindle shape, a tetrapot shape, and an indefinite shape can be used. In the present invention, the role of the inorganic filler is to modify the surface state of the injection-molded product and to change the flow state in the melt flow field. Therefore, the shape is preferably a spherical shape other than the balloon shape, particularly the needle shape, A plate shape is preferred. The average particle size of the inorganic filler used in the present invention is, for example, 0.01 to 10.0 μm, preferably 0.10 to 5.0 μm. Here, the average particle diameter means a particle diameter at which the cumulative value of the particle size distribution measurement curve measured by a liquid phase precipitation method based on JIS Z8820 is 50%. An average particle size of 0.10 μm or more is preferable because secondary agglomeration is not caused during kneading and mechanical properties are not lowered. Moreover, if it is 10.0 micrometers or less, since a mechanical physical property, especially impact resistance are not reduced, it is preferable. Furthermore, the specific gravity of the inorganic filler used in the present invention is preferably 3 or less. When the specific gravity is large, the volume occupied by the inorganic filler in the system is reduced when the same weight is added as compared to a small one, and the effect of adding the inorganic filler is reduced. Of course, the effect is exhibited by adding the volume ratio together, but the specific gravity of the inorganic filler is preferably 3 or less because the specific gravity of the molded product is increased and the productivity is lowered.

The method for producing the inorganic filler of the present invention is a method of mechanically pulverizing bulk particles, a method of colliding in a high-speed air stream, a thermal decomposition method, an atomizing method, a spray method, a colloid method, a uniform precipitation method, an alkoxide method, a hydrothermal synthesis method. , Microemulsion method, solvent evaporation method, sol-gel method, laser ablation method, CVD method, PVD method, etc., but any method may be used. Moreover, you may use the inorganic filler by which the inorganic surface treatment was given to the surface. Examples of the inorganic surface treatment include a method of coating with a metal oxide such as silicon oxide, and a method of doping a metal such as Al, Mn, Cu, Zn, Zr, Ag, Cl, Ce, Eu, Tb, and Er. It is done. There are several types of surface treatment with inorganic oxides, and one or several layers may be coated. However, with metal oxides such as zinc oxide and titanium oxide, silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, etc. Often one or two layers are coated.

The metal doping method is excellent in reducing the activity of the nanoparticle surface, but is also used for the purpose of imparting new characteristics. For example, conductivity can be imparted by doping aluminum into zinc oxide. Furthermore, the inorganic filler of the present invention may be an inorganic filler subjected to an organic surface treatment. As this surface treating agent, higher fatty acid, higher fatty acid alkali metal salt, polyhydric alcohol higher fatty acid ester, anionic surfactant, phosphate ester, silane coupling agent, aluminum coupling agent, titanate coupling agent, organosilane At least one selected from organosiloxane and organosilazane is used. The inorganic surface treatment and the organic surface treatment may be performed alone or both.

The carbon nanotubes used in the present invention may be used after making a predispersed dispersion in advance. The preliminary dispersion is obtained by mechanically dispersing carbon nanotubes and at least one wax selected from polyethylene wax, polypropylene wax, paraffin wax, carnauba wax, montan wax, acid-modified olefin wax, and the like. By using a pre-dispersion, the dispersibility is better than when carbon nanotubes are added directly to the resin. When the polyolefin resin used as the base in the present invention is a polypropylene resin, it is preferable to use a pre-dispersion using a polypropylene wax having good compatibility. Use of a pre-dispersion using polyethylene wax for polypropylene resin is not preferable because carbon nanotubes having high affinity with polyethylene do not disperse well.

On the other hand, when the polyolefin-based resin as a base is a resin containing a polyethylene-based resin, it is preferable to use a pre-dispersion using polyethylene wax because the dispersibility is good. There are dispersers, super mixers, Henschel mixers, high speed mixers, mortars, internal mixers, kneaders, Banbury mixers, twin-screw kneaders, sand mills, ball mills, roll mills, etc. A roll mill is preferably used. The roll mill mainly includes two rolls and three rolls, but a three roll mill having a large shearing force is particularly preferable in order to increase dispersibility.

The compounding ratio of carbon nanotubes and wax in the preliminary dispersion is preferably 40% by weight or less of carbon nanotubes in the preliminary dispersion. If it exceeds 40% by weight, the viscosity of the preliminary dispersion becomes hard due to the high oil absorption rate of the carbon nanotubes, which is not preferable because the dispersibility is significantly lowered. When preparing a preliminary dispersion containing 40% by weight or more of carbon nanotubes, it is preferable to use a liquid dispersion medium alone or in combination with the wax in order to lower the viscosity of the preliminary dispersion. When only the liquid dispersion medium is used, there are problems such as dispersibility and bleeding, and it is more preferable to use the wax and the liquid dispersion medium in combination. Examples of the liquid dispersion medium include plasticizers, room temperature molten salts, silicone oil, polyethylene glycol, surfactants, and the like, but it is preferable to use room temperature molten salts from the viewpoint of heat resistance.

The above-mentioned room temperature molten salt is a general term for salts that are liquid near room temperature, and is a salt composed of a cation and an anion that is liquid in a wide range near room temperature and that has a very low vapor pressure near room temperature. is there.

The cation of the room temperature molten salt is imidazolium, pyridinium, ammonium, phosphonium, sulfonium, for example, dialkylimidazolium, trialkylimidazolium, alkylpyridinium, dialkylpyridinium, trialkylpyridinium, 1-fluoroalkylpyridinium, 1- Examples include fluorotrialkylpyridinium, tetraalkylammonium, tetraalkylphosphonium, and trialkylsulfonium.

More specific examples include 1,3-dimethylimidazolium, 1-ethyl-3-methylimidazolium, 1-propyl-3-methylimidazolium, 1-methyl-3-propylimidazolium, 1-butyl- 3-methylimidazolium, 1-hexyl-3-methylimidazolium, 1-octyl-3-methylimidazolium, 1-methyl-3-octylimidazolium, 1-decyl-3-methylimidazolium, 1-dodecyl- 3-methylimidazolium, 1-tetradodecyl-3-methylimidazolium, 1-hexadodecyl-3-methylimidazolium, 1-octadodecyl-3-methylimidazolium, 1-ethyl-2,3-dimethylimidazolium 1-propyl-2,3-dimethylimidazolium, 1,2-dimethyl-3-propyl Pyrimimidazolium, 1-butyl-2,3-dimethylimidazolium, 1-hexyl-2,3-dimethylimidazolium, 1-octyl-2,3-dimethylimidazolium 1,2-dimethyl-3-octylimidazolium 1-butyl-3-ethylimidazolium, 1-hexyl-3-ethylimidazolium, 1-ethyl-3-octylimidazolium, 1-ethyl-3-butylimidazolium, 1-ethyl-3-hexylimidazolium 1-octyl-3-ethylimidazolium, 1,2-diethyl-3,4-dimethylimidazolium, 1-fluoropyridinium, 1-fluoro-2,4,6-trimethylpyridinium, 1-ethylpyridinium, 1- Butyl pyridinium, 1-hexyl pyridinium, 1-propyl 3-methyl pyridi 1-butyl-4-methylpyridinium, 1-butyl-3-methylpyridinium, 1-hexyl-4-methylpyridinium, 1-hexyl-3-methylpyridinium, 1-octyl-4-methylpyridinium, 1- Octyl-3-methylpyridinium, 1-butyl-3,4-dimethylpyridinium, 1-butyl-3,5-dimethylpyridinium, trimethylpentylammonium, trimethylhexylammonium, trimethylheptylammonium, trimethyloctylammonium, triethylpropylammonium, triethyl (2-methoxyethyl) ammonium, methyl trioctyl ammonium, triethyl pentyl ammonium, triethyl heptyl ammonium, dimethyl ethyl propyl ammonium, dimethyl butyl ether Tillammonium, dimethylethylpentylammonium, dimethylethylhexylammonium, dimethylethylheptylammonium, dimethylethylnonylammonium, dimethylethylheptadecylammonium, dimethyldipropylammonium, dimethylbutylpropylammonium, dimethylpropylpentylammonium, dimethylhexylpropylammonium, dimethylheptyl Propyl ammonium, dimethyl butyl pentyl ammonium, dimethyl butyl hexyl ammonium, dimethyl butyl heptyl ammonium, dimethyl hexyl pentyl ammonium, diethyl heptyl methyl ammonium, dihexyl dimethyl ammonium, dipropyl butyl hexyl ammonium, dihexyl dipropyl ammonium Diethylmethylpropylammonium, diethylmethyl (2-methoxyethyl) ammonium, dipropylethylmethylammonium, diethylpropylpentylammonium, diethylmethylpentylammonium, ethylmethylpropylpentylammonium, dipropylmethylpentylammonium, dibutylmethylpentylammonium, dibutylhexyl Examples include methylammonium, trihexyltetradecylphosphonium, triisobutylmethylphosphonium, tetrabutylphosphonium, and triethylsulfonium.

As an anion of room temperature molten salt, hexafluorophosphate, tetrafluoroborate, methylsulfonic acid, trifluoromethanesulfonic acid, bistrifluoromethanesulfonic acid imide, bispentafluoroethanesulfonic acid imide, biscyanoimide, nitric oxide, acetic acid, And trifluoromethanecarboxylic acid.

Specific examples of the room temperature molten salt include 1-butyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium hydrogen sulfate, 1-butyl-3- Methyl imidazolium methanesulfonic acid, 1-butyl-3-methylimidazolium methyl sulfate, 1-butyl-3-methylimidazolium tetrachloroaluminate, 1-butyl-3-methylimidazolium thiocyanate, 1-ethyl-2, 3-dimethylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazole Lium High Rogen sulfate, 1-ethyl-3-methylimidazolium methanesulfonic acid, 1-ethyl-3-methylimidazolium tetrachloroaluminate, 1-ethyl-3-methylimidazolium thiocyanate, 1-methylimidazolium chloride, 1 -Methylimidazolium hydrogen sulfate, 1,2,3-trimethylimidazolium methyl sulfate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium chloride, 1-butyl-3- Methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluoroantimonate, 1-butyl-2,3-dimethylimid Zorium tetrafluoroborate, 1-dodecyl-3-imidazolium iodide, 1-ethyl-2,3-dimethylimidazolium trifluoromethanesulfonic acid, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl- 3-methylimidazolium nitrate, 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1,2-dimethyl-3-propylimidazolium bis (trifluoromethylsulfonyl) imide, 1,2- Dimethyl-3-propylimidazolium bis (pentafluoroethylsulfonyl) imide, 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-butyl-3-methylimidazolium hexafluorophosphate, 1 -Butyl-3-methylimidazolium octyl sulfate, 1-butyl-3-methylimidazolium tosylate, 1-ethyl-3-methylimidazolium tosylate, 1-methyl-3-octylimidazolium hexafluorophosphate, 1- Methyl-3-octylimidazolium tetrafluoroborate, 4- (3-butyl-1-imidazolio) -1-butanesulfonic acid triflate, 4- (3-butyl-1-imidazolio) -1-butanesulfonate, 1-aryl-3-methylimidazolium chloride, 1-benzyl-3-methylimidazolium chloride, 1-benzyl-3-methylimidazolium hexafluorophosphonate, 1-benzyl-3-methylimidazolium tetrafluoroborate, 1-butyl-2,3- Methylimidazolium chloride, 1-butyl-3-methylimidazolium 2- (2-methoxyethoxy) -ethyl sulfate, 1-hexyl-3-methylimidazolim hexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethane 1-butyl-3-methylpyridinium bis (trifluoromethylsulfonyl) imide, 3-methyl-1-propylpyridinium bis (trifluoromethylsulfonyl) imide, 1-butyl-4-methylpyridinium tetrafluoroborate, 1 -Butyl-4-methylpyridinium bromide, 1-butyl-4-methylpyridinium chloride, 1-butyl-4-methylpyridinium hexafluorophosphate, tributylmethylammonium methylsal , Methyl-trioctylammonium bis (trifluoromethylsulfonyl) imide, tetrabutylammonium bis (trifluoromethylsulfonyl) imide, tetraethylammonium trifluoromethanesulfonate, tetrabutylammonium bromide, methyltrioctylammonium thiosalicylate, Tetrabutylammonium benzoate, tetrabutylammonium methanesulfonate, tetrabutylammonium nonafluorobutanesulfonate, tetrabutylammonium heptadecafluorooctane sulfonate, tetrahexylammonium tetrafluoroborate, tetraoctylammonium chloride, tetrapentylammonium thiocyanate Tetrabutylammonium bromide Tetraethylammonium trifluoroacetate, tetrabutylammonium iodide, tetrabutylphosphonium tetrafluoroborate, trihexyl tetradecylphosphonium bis (2,4,4-trimethylpentyl) phosphinate, trihexyl tetradecylphosphonium bis (trifluoromethylsulfonyl) amide , Trihexyltetradecylphosphonium bromide, trihexyltetradecylphosphonium chloride, trihexyltetradecylphosphonium decanoate, trihexyltetradecylphosphonium dicyanamide, trihexyltetradecylphosphonium hexafluorophosphate, triisobutylmethylphosphonium tosylate, 3 -(Triphenylphosphonio) propane-1-sulfonic acid, Examples include 3- (triphenylphosphonio) propane-1-sulfonate, tetrabutylphosphonium-p-toluene "sulfonate, and triethylsulfonium bis (trifluoromethylsulfonyl) imide.

When normal temperature molten salt and wax are used in the preliminary dispersion, the preliminary dispersion is 40 to 70% by weight of carbon nanotubes, 20 to 55% by weight of wax, and 5 to 30% by weight of normal temperature molten salt in the preliminary dispersion. Use the body.

The production of the resin composition in the present invention is not particularly limited. For example, polyolefin resins, carbon nanotubes, inorganic fillers, and various additives and colorants as required, and mixing with a Henschel mixer, tumbler, disper, etc. kneader, roll mill, super mixer, Henschel mixer, Shugi mixer, Vertical granulator, high speed mixer, fur matrix, ball mill, steel mill, sand mill, vibration mill, batch mixer such as attritor, Banbury mixer, twin screw extruder, single screw extruder, rotor type twin screw kneader The resin composition in the form of pellets, powders, granules, beads or the like can be obtained by mixing, melt-kneading and dispersing with the above.

The resin composition of the present invention may be a masterbatch containing a conductive composition at a relatively high concentration and diluted with a molding resin (base resin) at the time of molding, or the concentration of the conductive composition may be It may be a compound that is relatively low and is used for molding with the same composition without being diluted with the resin to be molded.

The molded article of the present invention may be obtained by any one of extrusion molding, injection molding, and blow molding, or may be a powder paint obtained by pulverizing a resin composition.
In the resin composition of the present invention, suitable additives as necessary within the range not impairing the effects of the present invention, such as oxidation resistance stabilizer, weather resistance stabilizer, antistatic agent, dye, pigment, dispersant, A coupling agent or the like may be blended.

Next, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. The manufacturers and trade names of the polyolefin resin (A), carbon nanotube (B), and inorganic filler (C) in this example are shown below. The blending ratio of each component is shown in Table 1.
Polyolefin resin (A-1): Homopolypropylene resin (manufactured by Prime Polymer, Prime Polypro J105P)
Polyolefin resin (A-2): High-density polyethylene resin (manufactured by Asahi Kasei Chemicals Corporation, Suntec HD L50P)
Carbon nanotube (B): Multi-walled carbon nanotube produced by CCVD method having a wire diameter of 10 to 15 nm and a length of 0.1 to 10 μm (made by ARKEMA, GRAPHISTRENGTH C100)
Inorganic filler (C-1): Talc (Nihon Talc Co., Ltd., Microace SG-95)
Inorganic filler (C-2): Basic magnesium sulfate (manufactured by Ube Materials, Mosheidi)

1. Production of Resin Composition After drying the polyolefin resin (A) with a dehumidifying dryer, a predetermined amount of carbon nanotubes (B) and inorganic filler (C) are added to the polyolefin resin (A) for 4 minutes at a stirring blade rotation speed of about 300 rpm with a super mixer. , Stirred and mixed. After melt-kneading this with a twin screw extruder set to an appropriate processing temperature at which the polyolefin resin (A) does not change, a resin composition is prepared, and then an injection molding machine (IS-100F type manufactured by Toshiba Machine Co., Ltd.) is used. Molding was performed.
2. Evaluation The surface resistivity of the obtained molded product was measured using a surface resistance measuring instrument (TRUSSTAT ST-3) manufactured by SIMCO. The results are shown in Table 1.

Claims (5)

It consists of 25 to 98.5% by weight of polyolefin resin, 0.1 to 25% by weight of multi-walled carbon nanotubes, and 1 to 50% by weight of inorganic filler. The inorganic filler not only increases the concentration of carbon nanotubes in the resin, but also during injection molding. A resin composition in which carbon nanotubes are prevented from being unevenly distributed due to a spiral step, and a decrease in surface conductivity of a molded product is suppressed. The resin composition according to claim 1, wherein the polyolefin resin according to claim 1 comprises 30 to 100% by weight of polypropylene resin and 0 to 70% by weight of polyethylene resin. 3. The resin composition according to claim 1, wherein the inorganic filler according to claim 1 has a plate-like shape and a needle-like shape. The inorganic filler having plate-like and needle-like shapes according to claim 3 is talc, mica, hydrotalcite, plate-like calcium carbonate, wollastonite, potassium titanate, acicular magnesium hydroxide, aluminum borate, basic A resin composition characterized by being one or more selected from magnesium sulfate. The molded object which consists of a resin composition of Claims 1-4.