JP2022034316A - Carbon nanotube dispersion, and coating including the same - Google Patents

Abstract

To provide a conductive material dispersion having excellent compatibility with a binder and excellent storage stability, and a conductive coating having excellent conductivity and excellent transparency.SOLUTION: A conductive material dispersion contains a conductive material, a copolymer (A), a base (B), an antistatic agent (C), and water. The conductive material includes single-wall carbon nanotubes with an average outer diameter of 1-4 nm. The copolymer (A) contains (meth)acrylonitrile-derived units of 10 mass%-99 mass% and carboxyl group-containing monomer units of 1 mass%-90 mass% relative to 100 mass% of the total of all the units. The base (B) has a pKb of 5 or less in the water at 25°C, and a solubility of 1 g/100 ml or more in the water at 25°C. The solid content mass ratio between the copolymer (A) and the base (B), (B)/(A), is 0.2-1.0.SELECTED DRAWING: None

Description

The present invention comprises forming a conductive material dispersion containing carbon nanotubes having excellent compatibility with a paint binder and storage stability, a conductive paint containing a conductive material dispersion and a binder resin, and forming a film thereof. Concerning conductive coatings.

In recent years, materials having functions such as antistatic property, conductivity, thermal conductivity, and electromagnetic wave shielding property have been actively developed using materials containing carbon nanotubes. For example, a polymer such as polyamide, polyester, polyether or polyimide, or an inorganic material such as glass or ceramics material is used as a matrix, and carbon nanotubes are dispersed in these matrices to prevent static electricity, conductivity, and heat. Many studies have been conducted on composite materials having functions such as conductivity and electromagnetic wave shielding properties, and laminates obtained by laminating these composite materials.

For example, a transparent antistatic paint can be mentioned as an application using a carbon nanotube dispersion. In order to utilize the characteristics of carbon nanotubes by coating, it is necessary to form a network structure of carbon nanotubes dispersed on the substrate. This is expected to enable high transparency and conductivity to be exhibited even when the amount of carbon nanotubes used is extremely small.

Until now, a method of producing a conductive film by applying a conductive layer using carbon nanotubes onto the film has been known. However, in these known techniques, for example, Patent Document 1, since the coating film thickness becomes extremely thick in order to impart desired conductivity, transparency is ignored as a conductive substrate. Further, in Patent Document 2, in order to maintain the conductivity of the carbon nanotubes in the conductive layer, the conductive polymer of the conjugated polymerization system is used as the binder resin, but the conductive properties originally possessed by the carbon nanotubes are utilized. As a conductive film, the resistance value is extremely high. In Patent Document 3, since the conductive characteristics of carbon nanotubes are exhibited, the manufacturing process of the conductive film becomes complicated, and there is a problem in productivity and economy. In Patent Document 4, carbon nanotubes are applied in order to improve the adhesiveness between the conductive layer and the base material, and then a binder resin is overcoated on the carbon nanotubes, which causes problems in productivity and economy as in Patent Document 3. be. Further, since the four patent documents shown here use an organic solvent as a solvent, it cannot be said to be optimal in terms of environmental load.

Japanese Unexamined Patent Publication No. 2002-67209 Japanese Unexamined Patent Publication No. 2004-195678 Japanese Unexamined Patent Publication No. 2007-11123 Japanese Patent No. 366969

Even in the conventional technology so far, in order to produce a film in which carbon nanotubes are dispersed, carbon nanotubes are dispersed in a matrix or a resin. However, the dispersed state of the carbon nanotubes is not always good, and in the conventional lamination by coating, the binder resin inhibits the conductivity of the carbon nanotubes, and the carbon nanotubes agglomerate in the coating process and the drying process. It was difficult to express the original characteristics of.

An object of the present invention is to improve such drawbacks of the prior art and to provide a conductive material dispersion in which carbon nanotubes having excellent compatibility with a binder and storage stability are dispersed. Further, an object of the present invention is to provide a conductive coating material capable of achieving both good conductivity and transparency.

As a result of diligent studies to achieve the above object, the present inventors have found carbon nanotubes having a specific outer diameter as a conductive material, a copolymer having a specific structural unit as a dispersant, and a specific pKb. It has been found that a conductive material dispersion having good storage stability and compatibility can be produced by using the types and ratios of bases having solubility in water and antistatic agents. Furthermore, they have found that it is possible to produce a conductive coating material having both good conductivity and transparency.

That is, the present invention includes the following embodiments. The embodiments of the present invention are not limited to the following.

The present invention is a conductive material dispersion containing a conductive material, a copolymer (A), a base (B), an antistatic agent (C), and water.
The conductive material contains single-walled carbon nanotubes having an average outer diameter of 1 to 4 nm.
The copolymer (A) contains 10% by mass to 99% by mass of units derived from (meth) acrylonitrile and 1% by mass to 90% by mass of carboxyl group-containing monomer units, based on a total of 100% by mass of all units. It is a copolymer, and the base (B) has a pKb of 5 or less at 25 ° C. in water and a solubility of 1 g / 100 ml or more at 25 ° C. in water, and the copolymer (A) and the base (B). ), The solid content mass ratio (B) / (A) is 0.2 to 1.0, and the present invention relates to a conductive material dispersion.

The present invention also relates to the conductive material dispersion containing 11 to 40% by mass of a carboxyl group-containing monomer unit with respect to 100% by mass of the copolymer (A).

The present invention also relates to the conductive material dispersion, which is characterized in that the pKb of the base (B) is 1 or less.

The present invention also relates to the conductive material dispersion, wherein the carboxyl group-containing monomer contains acrylic acid and itaconic acid.

Further, the present invention is characterized in that the antistatic agent (C) contains at least one selected from the group consisting of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant. The present invention relates to the conductive material dispersion.

The present invention also relates to the conductive material dispersion, which is characterized by containing an acid.

The present invention also relates to the conductive material dispersion, which comprises a total of 20% by mass to 1000% by mass of the copolymer (A) and the base (B) with respect to the conductive material.

The present invention also relates to a conductive coating material containing the conductive material dispersion.

The present invention also relates to a conductive coating film, which is a coating film for the conductive coating material.

According to the embodiment of the present invention, it is possible to provide a conductive material dispersion in which carbon nanotubes having excellent compatibility with a binder and storage stability are dispersed. Further, according to the embodiment of the present invention, it is possible to provide a conductive coating material having both good conductivity and transparency.

<Conductive material>
The conductive material of this embodiment is a single-walled carbon nanotube. The single-walled carbon nanotube has a shape in which flat graphite is wound in a cylindrical shape, and has a structure in which one layer of graphite is wound.

The average outer diameter of the carbon nanotubes is 1 to 4 nm, preferably 1 to 2 nm. The average outer diameter of carbon nanotubes is determined by observing the morphology of carbon nanotubes with a transmission electron microscope (manufactured by JEOL Ltd.), measuring the lengths of 100 short axes, and using the number average value as the average outer diameter of carbon nanotubes (the average outer diameter of carbon nanotubes). nm).

The specific surface area of the carbon nanotubes is preferably 400 to 1200 m ² / g, more preferably 400 to 800 m ² / g. When the specific surface area is 400 m ² / g or more, a network of carbon nanotubes is easily formed in the coating film and the conductivity is improved, and when the specific surface area is 800 m ² / g or less, the carbon nanotubes are easily unraveled in the dispersion step. , Since the structural destruction of carbon nanotubes does not easily proceed, the conductivity is improved.

The carbon component of the carbon nanotubes is preferably 70 to 90% by mass, more preferably 80 to 90% by mass. The carbon nanotube (A) may contain a catalyst component, and the value obtained by subtracting the catalyst component from the carbon nanotube is referred to as a carbon component. The value of the carbon component was calculated according to the formula (1) by measuring the ash content after firing in the presence of 900 ° C. in the air for 5 hours.
Carbon component of carbon nanotube (%) =
1- (weight of ash after firing (g) / weight of carbon nanotubes before firing (g)) x 100
・ ・ ・ ・ Equation (1)
When the carbon component is in the range of 70 to 90% by mass, a good dispersion can be obtained. Known techniques include improving the yield in the process of producing carbon nanotubes and removing the catalyst component by acid purification of the obtained carbon nanotubes as means for increasing the carbon component, but this is not preferable because the conductivity is lowered.

The 50% particle size (D50) calculated by the laser diffraction type particle size distribution measurement of the carbon nanotubes is preferably 500 to 1300 μm, more preferably 800 to 1200 μm.

Examples of such carbon nanotubes (A) include ZEONANO SG101 (outer diameter: 3 to 5 nm) manufactured by Zeon Corporation, TUBALL (outer diameter: 1 to 2 nm) manufactured by OCSiAl, and the like as single-walled carbon nanotubes. It is not limited to these.

The dispersion of the present embodiment contains a copolymer (A) containing a unit derived from (meth) acrylonitrile and a carboxyl group-containing monomer unit, and has a pKb of 5 or less at 25 ° C. in water and 25 ° C. in water. Contains the base (B) having a solubility in 1 g / 100 ml or more.

The copolymer (A) and the base (B) are not particularly limited, but function as a dispersant for dispersing the conductive material, and may be used after being dissolved or semi-dissolved in water in advance, and may be dispersed. Sometimes it may be used while being dissolved or semi-dissolved.

<Copolymer (A)>
Examples of (meth) acrylonitrile include acrylonitrile and meta-acrylonitrile. One type can be used alone or in combination of two or more types, and acrylonitrile is preferable. When the monomer unit derived from (meth) acrylonitrile is acrylonitrile, the bending of the copolymer is reduced, and the adjacent cyano groups are oriented to form a partially structured structure with strong polarization. Alternatively, the intermolecular force between the dispersant and water increases. The content of the monomer unit derived from (meth) acrylonitrile is 10% by mass to 99% by mass, and from the viewpoint of increasing the intermolecular force, 52% by mass is based on the mass of all the monomer units constituting the copolymer. The above is preferable, 60% by mass or more is preferable, and 70% by mass or more is more preferable. Based on the mass of all the monomer units constituting the copolymer, it is preferably 89% by mass or less, and more preferably 85% by mass or less. By setting the content of the monomer unit derived from (meth) acrylonitrile in the above range, the dispersion can be stably present in the dispersion medium.

The carboxyl group-containing monomer unit is a unit derived from the carboxyl group-containing monomer, and examples of the carboxyl group-containing monomer include (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, and citraconic acid. Saturated fatty acids, 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxypropylphthalate, 2- (meth) acryloyloxyethyl hexahydrophthalate, 2- (meth) acryloyloxypropylhexahydrophthalate, ethylene oxide modification Examples thereof include carboxyl group-containing (meth) acrylates such as succinic acid (meth) acrylate and β-carboxyethyl (meth) acrylate. In addition, an acid anhydride group-containing monomer such as maleic anhydride, itaconic anhydride, and citraconic anhydride, which are multimers of the hydroxyl group-containing monomer, and monofunctional alcohol adducts thereof and the like can be mentioned. "-C (= O) -OC (= O)-" (referred to as "acid anhydride group" in the present specification), which is a group having a structure in which two carboxyl groups are dehydrated and condensed, is also a carboxyl group by hydrolysis. In the present specification, it is included in the carboxyl group in order to form. As the carboxyl group-containing monomer, unsaturated fatty acids are preferable, (meth) acrylic acid is more preferable, and acrylic acid is even more preferable. Further, it is more preferable to contain both acrylic acid and itaconic acid. The content of the carboxyl group-containing monomer unit is 1% by mass to 90% by mass, and from the viewpoint of having an appropriate affinity with water as a dispersion medium, the mass of all the monomer units constituting the copolymer is used as a reference. It is preferably 11% by mass or more, and more preferably 15% by mass or more. Based on the mass of all the monomer units constituting the copolymer, it is preferably 48% by mass or less, preferably 40% by mass or less, and more preferably 30% by mass or less.

The copolymer (A) may contain one or more monomer units selected from the group consisting of an active hydrogen group-containing monomer (excluding a carboxyl group), a basic monomer, and a (meth) acrylic acid alkyl ester. By selecting and containing the above-mentioned monomer according to the characteristics such as hydrophilicity, hydrophobicity, acidity, and basicity of the base material to which the conductive material dispersion of the present invention is applied and the material to be mixed, it can be applied to various uses. be able to. The content of one or more monomer units selected from the group consisting of active hydrogen group-containing monomers (excluding carboxyl groups), basic monomers, and (meth) acrylic acid alkyl esters is the content of all the monomers constituting the copolymer. Based on the mass of the unit, 20% by mass or less is preferable, 10% by mass or less is more preferable, and 5% by mass or less is further preferable.
When it is included in the above range, it is possible to impart appropriateness to various uses while maintaining a high intramolecular force.
Of one or more monomer units selected from the group consisting of an active hydrogen group-containing monomer (excluding a carboxyl group), a basic monomer, and a (meth) acrylic acid alkyl ester used for the synthesis of the copolymer (A). The active hydrogen group-containing monomer is a monomer having, for example, a hydroxyl group, a primary amino group, a secondary amino group, a mercapto group, or the like as an active hydrogen group. Here, the "primary amino group" means -NH ₂ (amino group), and the "secondary amino group" means that one hydrogen atom on the primary amino group is replaced with an organic residue such as an alkyl group. Means the group that was made. However, the primary amino group and the secondary amino group in the acid amide are not included in the active hydrogen group in the present specification.

The hydroxyl group-containing monomer is, for example, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate, 4-hydroxyvinylbenzene, 2-hydroxy. Examples thereof include -3-phenoxypropyl acrylate or a caprolactone adduct of these monomers (the number of moles added is 1 to 5). Among the active hydrogen group-containing monomers, a hydroxyl group-containing monomer is preferable from the viewpoints of easy availability of raw materials, ease of handling, affinity with a dispersion medium described later, and the like. The hydroxyl group-containing monomer is preferably hydroxyalkyl (meth) acrylate, more preferably hydroxyethyl (meth) acrylate, and even more preferably hydroxyethyl acrylate.

The primary amino group-containing monomer is, for example, aminomethyl (meth) acrylate, aminoethyl (meth) acrylate, allylamine hydrochloride, allylamine dihydrogen phosphate, 2-isopropenylaniline, 3-vinylaniline, 4-vinylaniline. And so on.

Examples of the secondary amino group-containing monomer include t-butylaminoethyl (meth) acrylate and the like.

Examples of the mercapto group-containing monomer include 2- (mercaptoacetoxy) ethyl acrylate, allyl mercaptan and the like.

The active hydrogen group-containing monomer can be used alone or in combination of two or more.

The basic monomer is a monomer having a basic group. Examples of the basic group include a tertiary amino group, an amide group, a pyridine ring, a maleimide group and the like. Although the monomer having a primary amino group and the monomer having a secondary amino group may be included in the basic monomer, they are treated as the active hydrogen group-containing monomer in the present invention and are not included in the basic monomer. ..

The basic monomer is, for example, dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylate;
N-substituted (meth) acrylamides such as (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, and acryloyl morpholine;
Heterocyclic aromatic amine-containing vinyl monomers such as 1-vinylpyridine, 4-vinylpyridine, 1-vinylimidazole;
N- (alkylaminoalkyl) (meth) acrylamides such as N- (dimethylaminoethyl) (meth) acrylamide and N- (dimethylaminopropyl) acrylamide;
Examples thereof include N, N-alkyl (meth) acrylamides such as N, N-dimethyl (meth) acrylamide and N, N-diethyl (meth) acrylamide.

The basic monomer can be used alone or in combination of two or more. Among the basic monomers, dimethylaminoethyl (meth) acrylate or dimethylaminopropyl (meth) acrylate is preferable, and dimethylaminoethyl is preferable from the viewpoint of easy availability of raw materials, ease of handling, and compatibility with the dispersion medium described later. Acrylate is more preferred.

The (meth) acrylic acid alkyl ester has a structure represented by (R ¹ ) ₂ C = C-CO-O-R ² (where R ¹ is a hydrogen atom or a methyl group and at least one of them is a hydrogen atom. , R ² is an alkyl group which may have a substituent).
Those containing the active hydrogen group or the basic group as the substituent of the alkyl group are treated as the active hydrogen group-containing monomer or the basic monomer and are not included in the (meth) acrylic acid alkyl ester.
Examples of the (meth) acrylic acid alkyl ester include a chain alkyl group-containing (meth) acrylic acid ester such as methyl (meth) acrylate and ethyl (meth) acrylate;
Branched alkyl group-containing (meth) acrylic acid esters such as 2-ethylhexyl (meth) acrylate and isostearyl (meth) acrylate;
Cyclic alkyl group-containing (meth) acrylic acid esters such as (meth) cyclohexyl acrylate and (meth) isobornyl acrylate;
Aromatic ring-substituted alkyl group-containing (meth) acrylic acid alkyl esters such as (meth) benzyl acrylate and (meth) phenoxyethyl acrylate;
(Meta) acrylic acid alkyl esters substituted with fluorogroups such as trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate;
Epoxy group-containing (meth) acrylic acid alkyl esters such as (meth) glycidyl acrylate and (meth) acrylic acid (3-ethyloxetane-3-yl) methyl;
3-silyl ether group-containing (meth) acrylic acid alkyl esters such as methacryloxypropylmethyldimethoxysilane;
Alkyloxy group-containing (meth) acrylic acid alkyl esters such as 2-methoxyethyl (meth) acrylic acid and polyethylene glycol monomethyl ether (meth) acrylic acid;
Examples thereof include cyclizationally polymerizable monomers such as 2- (allyloxymethyl) methyl acrylate.

The (meth) acrylic acid alkyl ester can be used alone or in combination of two or more.
Among the (meth) acrylic acid alkyl esters, ethyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylic from the viewpoint of availability of raw materials, ease of handling, and compatibility with the dispersion medium described later. 2-Ethylhexyl acrylate and lauryl (meth) acrylate are preferable, and 2-ethylhexyl acrylate and lauryl acrylate are more preferable.

The copolymer (A) of the present invention may further have another monomer unit. The monomers constituting the other monomer unit are, for example, styrene and styrenes such as α-methylstyrene;
Vinyl ethers such as ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, and isobutyl vinyl ether;
Vinyl acetate and fatty acid vinyls such as vinyl propionate;
N-substituted maleimides such as N-phenylmaleimide, N-cyclohexylmaleimide, etc .;
Heterocyclic (meth) acrylates such as tetrahydroflufreel (meth) acrylate or 3-methyloxetanyl (meth) acrylate; and the like can be mentioned.

The method for producing the copolymer (A) is not particularly limited, and examples thereof include a solution polymerization method, a suspension polymerization method, a bulk polymerization method, an emulsion polymerization method, a precipitation polymerization method, and the like, and a solution polymerization method or a precipitation polymerization method. Is preferable. Examples of the polymerization reaction system include addition polymerization such as ion polymerization, free radical polymerization, and living radical polymerization, and free radical polymerization or living radical polymerization is preferable. Further, examples of the radical polymerization initiator include peroxides, azo-based initiators and the like. A molecular weight modifier such as a chain transfer agent can be used in the polymerization of the dispersant.

Chain transfer agents include, for example, alkyl mercaptans such as octyl mercaptan, nonyl mercaptan, decyl mercaptan, dodecyl mercaptan, 3-mercapto-1,2-propanediol, octyl thioglycolate, nonyl thioglycolate, thioglycolic acid-2. Examples thereof include thioglycolic acid esters such as ethylhexyl, 2,4-diphenyl-4-methyl-1-pentene, 1-methyl-4-isopropylidene-1-cyclohexene, α-pinene, β-pinene and the like. In particular, 3-mercapto-1,2-propanediol, thioglycolic acid esters, 2,4-diphenyl-4-methyl-1-pentene, 1-methyl-4-isopropylidene-1-cyclohexene, α-pinene, β-Pinene and the like are preferable because the obtained polymer has a low odor.

The amount of the chain transfer agent used is preferably 0.01 to 4% by mass, more preferably 0.1 to 2% by mass, based on 100% by mass of all the monomer units. By setting the chain transfer agent in the above range, the molecular weight of the dispersant of the present invention can be adjusted to a suitable molecular weight range.

The weight average molecular weight of the dispersant is a polystyrene-equivalent weight average molecular weight, preferably 5,000 or more, more preferably 6,000 or more, and even more preferably 7,000 or more. Further, 400,000 or less is preferable, 200,000 or less is more preferable, 100,000 or less is further preferable, and 60,000 or less is particularly preferable. Having an appropriate weight average molecular weight improves the adsorptivity to the dispersion, and further improves the stability of the dispersion.

The acid value of the copolymer (A) can be determined by neutralization titration of KOH. The acid value of the copolymer (A) is preferably 30 mgKOH / g or more, more preferably 55 mgKOH / g or more, still more preferably 70 mgKOH / g or more. Further, 400 mgKOH / g or less is preferable, 300 mgKOH / g or less is more preferable, and 200 mgKOH / g or less is further preferable. By setting the acid value of the copolymer (A) in the above range, the affinity between the copolymer (A) and the dispersion medium can be appropriately controlled, and the affinity with the dispersion medium can be effectively controlled while being good. It will be possible to maintain a stable state of dispersion. When the acid value of the copolymer (A) exceeds the above range, the affinity for the dispersion medium becomes too high (that is, the solubility in water becomes too high), and when it falls below the above range, the affinity for the dispersion medium becomes too high. It may be too low (ie, too low in solubility in water), and in either case the action as the copolymer (A) may be low. Further, by setting both the amount of acidic groups of the conductive material and the acid value of the copolymer (A) within the above ranges, the affinity balance between the copolymer (A), the dispersion medium and the object to be dispersed is balanced. Is further improved, and the dispersibility is improved.

<Base (B)>
The conductive material dispersion of the present embodiment contains a base (B) having a pKb of 5 or less at 25 ° C. in water and a solubility of 1 g / 100 ml or more at 25 ° C. in water. The pKb is preferably 2 or less, more preferably 1 or less. The solubility is preferably 10 g / 100 ml or more, more preferably 30 g / 100 ml or more. As a result, the surface of the conductive material is modified, the adsorption of the copolymer (A) is further strengthened, and the dispersion stability of the dispersion is improved. The inorganic base is preferably a compound having at least one of an alkali metal and an alkaline earth metal, and more particularly, chlorides, hydroxides, carbonates and nitrates of alkali metals and alkaline earth metals. Examples thereof include sulfates, phosphates, tungstates, vanadium salts, molybdates, niobates, borates and the like. Among these, alkali metals, chlorides of alkaline earth metals, hydroxides and carbonates are preferable in terms of easily supplying cations. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide and the like. Examples of the carbonate of the alkali metal include lithium carbonate, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate and the like. Further, as a base containing no metal, ammonia can be mentioned. Of these, lithium hydroxide and sodium hydroxide are more preferable. The metal contained in the inorganic base and the inorganic metal salt of the present invention may be a transition metal.

Examples of the organic base include primary, secondary, tertiary or quaternary alkylamines having an alkyl group having 1 to 40 carbon atoms which may be substituted.

Primary alkylamines having an optionally substituted alkyl group having 1 to 40 carbon atoms include methylamine, ethylamine, propylamine, butylamine, isobutylamine, 2-ethylhexylamine, laurylamine, stearylamine, oleylamine, and 2 -Aminoethanol, 3-aminopropanol, 3-ethoxypropylamine and the like can be mentioned.

Examples of the secondary alkylamine having an alkyl group having 1 to 40 carbon atoms which may be substituted include dimethylamine, diethylamine, dipropylamine, 2-methylaminoethanol and the like.

Examples of the tertiary alkylamine having an alkyl group having 1 to 40 carbon atoms which may be substituted include trimethylamine, triethylamine, 2- (dimethylamino) ethanol and the like.

Examples of the quaternary alkylamine having an alkyl group having 1 to 40 carbon atoms which may be substituted include tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethyl (2-hydroxyethyl) ammonium hydroxide and the like.

Of these, primary, secondary, tertiary or quaternary alkylamines having an alkyl group having 1 to 10 carbon atoms which may be substituted are preferable, and an alkyl group having 1 to 5 carbon atoms which may be substituted may be used. Primary, secondary, tertiary or quaternary alkylamines having are more preferred.
Further, the alkyl group which may be substituted means that a hydrogen atom may be substituted, and examples of the substituent include a hydroxy group and the like.

Examples of the organic base include 1,8-diazabicyclo [5.4.0] undecene-7 (DBU), 1,5-diazabicyclo [4.3.0] nonen-5 (DBN), and 1,4-diazabicyclo [2]. .2.2] Compounds containing a basic nitrogen atom such as octane (DABCO), tri-n-butylamine, dimethylbenzylamine, monoethanolamine, imidazole, and 1-methylimidazole may be used.

The conductive material dispersion of the present embodiment preferably has a solid content mass ratio (B) / (A) of the copolymer (A) and the base (B) of 0.2 to 1.0. 0.2 to 0.5 is more preferable, and 0.2 to 0.4 is further preferable.

<Antistatic agent (C)>
The conductive material dispersion of the present embodiment contains an antistatic agent (C). By bleeding on the surface of the obtained conductive coating film, the antistatic agent (C) acts as a conductive auxiliary agent for carbon nanotubes, and even if the addition rate of carbon nanotubes is low, conductivity is likely to be exhibited. Further, by bleeding on the surface of the conductive coating film, it acts as a leveling agent for the coating film, and the appearance of the conductive coating film is improved. A surfactant can be preferably used as the antistatic agent (C). Surfactants are mainly classified into anionic, cationic, nonionic and amphoteric, and these surfactants are not particularly limited, but the following compounds can be exemplified as suitable examples.

Anionic surfactants include fatty acid salts, polysulfonates, polycarboxylates, alkylsulfate esters, alkylarylsulfonates, alkylnaphthalene sulfonates, dialkylsulfonates, dialkylsulfosuccinates, and alkylphosphates. Salts, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkylaryl ether sulfates, naphthalene sulfonic acid formarin condensates, polyoxyethylene alkyl phosphate sulfonates, glycerol borate fatty acid esters, polyoxyethylene glycerol fatty acid esters, etc. Specific examples thereof include sodium dodecylbenzene sulfonate, sodium lauryl sulfate, sodium polyoxyethylene lauryl ether sulfate, polyoxyethylene nonylphenyl ether sulfate ester salt, and sodium salt of β-naphthalene sulfonic acid formarin condensate. ..

Cationic activators include alkylamine salts and quaternary ammonium salts, specifically stearylamine acetate, trimethyl palm ammonium chloride, trimethyl beef ammonium chloride, dimethyldiolyl ammonium chloride, methyloleyldiethanol chloride, tetramethyl. Ammonium chloride, laurylpyridinium chloride, laurylpyridinium bromide, laurylpyridinium disulfate, cetylpyridinium bromide, 4-alkyl mercaptopyridine, poly (vinylpyridine) -dodecyl bromide, dodecylbenzyltriethylammonium chloride and the like can be mentioned.

Examples of the nonionic activator include polyoxyethylene alkyl ether, polyoxyalkylene derivative, polyoxyethylene phenyl ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, alkylallyl ether, and the like, and specifically, polyoxyethylene. Examples thereof include lauryl ether, sorbitan fatty acid ester, and polyoxyethylene octylphenyl ether. Examples of the amphoteric tenside agent include aminocarboxylates, alkyl betaine types, and alkyl imidazoline derivatives.

Since the antistatic agent (C) is excellent in bleeding property on the surface of the coating film, an anionic surfactant is particularly preferable. The content of the antistatic agent (C) is preferably 0.5 to 10% by mass, more preferably 1 to 5% by mass, based on 100% by mass of the conductive material dispersion.

In the conductive material dispersion of the present embodiment, the conductive material is placed in a dispersant carrier such as a dispersant and a binder resin and / or a dispersion medium in a kneader, a two-roll mill, a three-roll mill, a ball mill, a horizontal sand mill, and a vertical type. It can be finely dispersed and manufactured by using various dispersion means such as a sand mill, an annual type bead mill, a high pressure jet mill, or an attritor. At this time, two or more kinds of dispersions and the like may be simultaneously dispersed in the dispersion carrier and / or the dispersion medium, or separately dispersed ones may be mixed.

The solid content of the conductive material dispersion of the present embodiment is preferably 0.1 to 2% by mass, more preferably 0.2 to 1% by mass, based on 100% by mass of the conductive material dispersion.

The total amount of the copolymer (A) and the base (B) in the conductive material dispersion of the present embodiment is 1000% by mass or less when used as a transparent antistatic paint with respect to 100% by mass of the conductive material. It is preferable, 600% by mass or less is more preferable, and 500% by mass or less is particularly preferable. Further, 100% by mass or more is preferable, and 200% by mass or more is more preferable.

The conductive material dispersion of the present embodiment preferably includes a neutralization step of mixing an acid after dispersing at the above pH. The acid used is preferably an acid having a pKa of 2 or more at 25 ° C. in water. For example, acetic acid, phosphoric acid, carbonic acid and the like can be mentioned.

The conductive material dispersion of the present embodiment preferably has a pH of 8.0 to 13.0, more preferably 8.0 to 10.0.

The pH of the conductive material dispersion of the present embodiment is preferably 9.0 to 13.5, more preferably 10.0 to 13.0 in the dispersion step.

The binder for paint is not particularly limited as long as it is usually used as a binder resin for paint, and can be appropriately selected depending on the intended purpose. For example, a condensed synthetic resin, an additive synthetic resin, or a natural high molecular weight resin. Molecular compounds, etc. may be mentioned. Examples of the condensed synthetic resin include polyester resin, polyurethane resin, polyepoxy resin, polyamide resin, polyether resin, silicon resin and the like. Examples of the additive synthetic resin include a polyolefin resin, a polystyrene resin, a polyvinyl alcohol resin, a polyvinyl ester resin, a polyacrylic acid resin, an unsaturated carboxylic acid resin and the like.
Examples of the natural polymer compound include celluloses, rosins, and natural rubbers.
The resin may be used as a homopolymer, may be used as a copolymer and may be used as a composite resin, and any of a single-phase structure type, a core-shell type, and a power feed type emulsion can be used.

As the binder for paint, a binder in which the resin itself has a hydrophilic group and has self-dispersibility can be used, and a binder in which the resin itself does not have dispersibility and is imparted with a surfactant or a resin having a hydrophilic group and has dispersibility can be used. Among these, emulsions of resin particles obtained by emulsification and suspension polymerization of ionomers of polyester resins and polyurethane resins and unsaturated monomers are suitable. In the case of emulsion polymerization of an unsaturated monomer, the reaction is carried out with water containing an unsaturated monomer, a polymerization initiator, a surfactant, a chain transfer agent, a chelating agent, a pH adjuster, etc. to carry out a resin emulsion. Therefore, a binder for paint can be easily obtained, and the resin composition can be easily changed, so that the desired properties can be easily created.

Examples of the unsaturated monomer include unsaturated carboxylic acids, (meth) acrylic acid ester monomers, (meth) acrylic acid amide monomers, aromatic vinyl monomers, and vinyl cyano compounds. A body, a vinyl monomer, an allyl compound monomer, an olefin monomer, a diene monomer, an oligomer having an unsaturated carbon, and the like can be used alone or in combination of two or more. By combining these monomers, it is possible to flexibly modify the properties, and it is also possible to modify the properties of the resin by carrying out a polymerization reaction or a graft reaction using an oligomer-type polymerization initiator.

Examples of the unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid and the like.
Examples of the monofunctional (meth) acrylic acid esters include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, and 2-ethylhexyl methacrylate. , Octyl methacrylate, decyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, glycidyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, methacryloxyethyl trimethylammonium salt, 3 -Methyloxypropyltrimethoxysilane, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, decyl. Examples thereof include acrylate, dodecyl acrylate, octadecyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, glycidyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, dimethylaminoethyl acrylate, acryloxyethyl trimethylammonium salt, and the like. ..

Examples of the polyfunctional (meth) acrylic acid esters include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, and 1,4-butylene. Glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, polybutylene glycol dimethacrylate, 2,2'-bis (4-methacryloxydiethoxyphenyl) )
Propane, trimethylolpropane trimethacrylate, trimethylolethanetrimethacrylate, polyethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylate, 1,6-hexanediol di Acrylate, Neopentyl Glycol Diacrylate, 1,9-Nonandiol Diacrylate, Polypropylene Glycol Diacrylate, 2,2'-Bis (4-Acryloxipropyroxyphenyl) Propane, 2,2'-Bis (4-Acryloxy) Diethoxyphenyl) Propanetrimethylolpropanetriacrylate, trimethylolethanetriacrylate, tetramethylolmethanetriacrylate, ditrimethyloltetraacrylate, tetramethylolmethanetetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, and the like can be mentioned.

Examples of the (meth) acrylic acid amide monomers include acrylamide, methacrylamide, N, N-dimethylacrylamide, methylenebisacrylamide, 2-acrylamide-2-methylpropanesulfonic acid and the like.
Examples of the aromatic vinyl monomers include styrene, α-methylstyrene, vinyltoluene, 4-t-butylstyrene, chlorstyrene, vinylanisole, vinylnaphthalene, divinylbenzene and the like.

Examples of the vinyl cyano compound monomers include acrylonitrile and methacrylonitrile.
Examples of the allyl compound monomers include allylsulfonic acid or a salt thereof, allylamine, allyl chloride, diallylamine, diallyldimethylammonium salt and the like.
Examples of the olefin monomers include ethylene and propylene.
Examples of the diene monomers include butadiene and chloroprene.
Examples of the vinyl monomers include vinyl acetate, vinylidene chloride, vinyl chloride, vinyl ether, vinyl ketone, vinylpyrrolidone, vinyl sulfonic acid or a salt thereof, vinyl trimethoxysilane, vinyl triethoxysilane and the like.

Examples of the oligomer having unsaturated carbon include a styrene oligomer having a methacryloyl group, a styrene-acrylonitrile oligomer having a methacryloyl group, a methylmethacrylate oligomer having a methacryloyl group, a dimethylsiloxane oligomer having a methacryloyl group, and a polyester having an acryloyl group. Examples thereof include oligomers.

Specific examples of such paint binders include urethane resins manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd .: Superflex 110, Superflex 150, Superflex 210, Superflex 300, Superflex 420, Superflex 460, Superflex 470, Superflex 500M, Superflex 620, Superflex 650, Superflex 740, Superflex 820, Superflex 840, F-8082D, F-2951D, Made by Sumika Bayer Urethane: Bihydrour UH2606, Bihydrol UH650, Bihydrol UHXP2648, Bihydrol UHXP2650, Impranil DLC-F, Impranil DLN, Impranil DLP-R, Impranil DLS, Impranil DLU, Impranil XP2611, Impranil LPRSC1380, Impranil LPRSC1537, Impranil LPRSC1554, Impranil LPRSC3040, Impranil LPDSB10 Made by Ink Chemical Industry: Hydran HW-301, HW-310, HW-311, HW-312B, HW-333, HW-340, HW-350, HW-375, HW-920, HW-930, HW-940, HW-950, HW-970, AP-10, AP-20, ECOS3000, Sanyo Kasei Kogyo: UCOAT UWS-145, Permarin UA-150, Permarin UA-200, Permarin UA-300, Permarin UA-310, Eucoat UX -320, Permarin UA-368, Permarin UA-385, Eucoat UX-2510, Nichika Kagaku: Neo Sticker 100C, Eva Fanol HA-107C, Eva Fanol HA-50C, Eva Fanol HA-170, Eva Fanol HA-560, ADEKA: Examples thereof include the Adeka Bon Tita UHX-210 and the Adeka Bon Tita UHX-280. As polyolefin resin, Mitsubishi Chemical: APTPLOK series BW-5550, Toyobo: HARDLEN series EH-801, EW-5303, EW-5504, EW-5515, EW-8511, EZ-1000, EZ-2000, Nippon Paper Industries : Supercron series E-480T, E-415, E-412T, S-6375, S-6377 and the like can be mentioned. Examples of the alkyd resin include S118, S126 and S346 of the water sol series manufactured by Dainippon Ink Co., Ltd., 376 and 580 of the Arolon series manufactured by Nippon Shokubai, and ARL581 and ARL580 of the Acryset series manufactured by Nippon Shokubai.

The coating material of the present invention is a melamine resin, a urea resin, a polyisocyanate compound, a blocked polyisosianate compound, an epoxy compound or a resin, or a carboxyl group-containing compound, which has a role as a cross-linking agent capable of reacting with a functional group of a coating binder. Alternatively, a resin, an acid anhydride, an alkoxysilane group-containing compound, a resin, or the like can be used. It is desirable to use a resin containing a crosslinkable functional group and a resin having a role as a crosslinker in combination. Among them, one selected from acrylic resin, polyester resin, alkyd resin, melamine resin, epoxy resin and urea resin is used. It is more preferable to use one selected from acrylic resin, polyester resin, alkyd resin and melamine resin, and it is more preferable to use acrylic resin and melamine resin in combination.

The melamine resin is particularly preferably used because it has thermosetting properties and acts as a curing agent. The acrylic resin is preferably obtained by polymerizing a monomer having a polymerizable unsaturated double bond, which is well known to those skilled in the art, by a conventional method. Examples of the monomer having a polymerizable unsaturated double bond include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, etacrylic acid, propylacrylic acid, isopropylacrylic acid, itaconic acid, maleic anhydride and fumaric acid. Carboxylic acid group-containing monomer, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxyl group-containing monomer such as ε-caprolactone-modified acrylic monomer, (meth) acrylic acid Methyl, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, (meth) ) 2-Ethylhexyl acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate and other (meth) acrylic acid ester monomers , Styrene, α-methylstyrene, α-methylstyrene dimer, vinyltoluene, styrene-based monomers such as divinylbenzene and the like can be mentioned. Further, it is preferable to use a radical polymerization initiator or the like well known to those skilled in the art for polymerization.

Specific examples of the melamine resin include Cymel 300, 303, 325, 327, 350, 370 (manufactured by Mitsui Cytec), Nicarac MS15, MS17, MX430, MX650 (manufactured by Sanwa Chemical), and Sumimar M-55 (manufactured by Sumitomo Chemical). ), Methyl etherified melamine resin such as Regimin 740, 741 (manufactured by Monsanto); Cymel 202, 235, 238, 254, 272, 1130 (manufactured by Mitsui Cytec), Nicarac MX485, MX487 (manufactured by Sanwa Chemical), Regimin 755. Examples thereof include methyl ether / butyl ether mixed etherified melamine resin (manufactured by Monsanto). These melamine resins can be used alone or as a mixture of two or more.

Further, the conductive coating material of the present invention includes water or an organic solvent, a rheology control agent, a pigment dispersant, an antioxidant, a curing catalyst, an antifoaming agent, an antioxidant, an ultraviolet absorber, and a surface conditioner, if necessary. , Various additives such as preservatives, extender pigments and the like can be appropriately blended.

The content of the conductive material in the conductive coating material is preferably 0.005% by mass or more, preferably 0.01% by mass, and 0.02 based on the mass in the total solid content of the coating material. More preferably, it is by mass or more. Further, it is preferably 0.20% by mass or less, and more preferably 0.1% by mass or less.

The conductive coating material of the present invention can be prepared by mixing and dispersing the above-mentioned components. Further, a conductive material dispersion can be prepared in advance by mixing with the above resin component and water, and the conductive material dispersion can be mixed with the above-mentioned component and blended with the conductive paint.

<Conductive coating film>
The conductive coating film of the present invention is obtained by applying the conductive paint to a substrate and drying it. It is not particularly limited and can be applied to various base materials, for example, metal base materials such as iron, stainless steel, aluminum and its surface treated products; cement-based base materials such as cements, limes and plasters; polycarbonate chloride. Types, polyesters, polycarbonates, acrylics and other plastic-based substrates and the like can be mentioned. In addition, various objects to be coated in the field of building / building materials such as building materials, buildings, and structures made of these various base materials can be mentioned.

The method for applying the conductive coating material is not particularly limited, and examples thereof include brush coating, roller coating, and spray coating. After coating, a coating film can usually be obtained by drying at room temperature or heating. The coating amount; coating order such as undercoating, intermediate coating, and topcoating; coating film thickness; drying time and the like can be arbitrarily set according to the type of the conductive coating material and the base material to be applied.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. In the examples, "carbon nanotubes" may be abbreviated as "CNT". Unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass".

(Measuring method of acid value of dispersant)
The acid value of the dispersant was calculated from the titration of the dispersant / NMP solution. 1 g of the dispersant was collected in a beaker (100 ml), 30 ml of NMP was added, and the mixture was stirred with a stirrer to dissolve. Further, it was diluted with 20 ml of ion-exchanged water to obtain a titrated constant solution. The titrated solution is separately titrated with a 0.1 mol / l KOH / ethanol solution using a potential difference automatic titrator (AT-710S, manufactured by Kyoto Denshi Kogyo), and the acid value of the dispersant is determined from the titration at the isoelectric point. mgKOH / g) was calculated.

(Measuring method of weight average molecular weight (Mw))
The weight average molecular weight (Mw) of the synthesized dispersant was measured by gel permeation chromatography (GPC) equipped with an RI detector.
The device used HLC-8320GPC (manufactured by Tosoh), three separation columns were connected in series, and the fillers were "TSK-GELSUPER AW-4000", "AW-3000", and "AW-2500" manufactured by Tosoh in order. Was measured at an oven temperature of 40 ° C., a solution of 30 mM triethylamine and 10 mM LiBr in N, N-dimethylformamide as an eluent at a flow rate of 0.6 ml / min. The sample was prepared in a solvent consisting of the above eluent at a concentration of 1 wt%, and 20 microliters were injected. The molecular weight is a polystyrene-equivalent value.

(Method of measuring specific surface area of conductive material)
The conductive material was weighed at 0.03 g using an electronic balance (manufactured by Sartorius, MSA225S100DI), and then dried at 110 ° C. for 15 minutes while degassing. Then, the specific surface area (m ² / g) of the conductive material was measured using a fully automatic specific surface area measuring device (HM-model 1208 manufactured by MOUNTECH).
(Measuring method of dispersed particle size of conductive material dispersion)
The dispersion particle size was determined by a determination method according to JIS K5600-2-5 using a grind gauge having a maximum groove depth of 300 μm.

(Method for measuring the particle size of the median diameter of the conductive material dispersion)
For the particle size distribution of the conductive material dispersion, a 50% particle size (Median diameter, D50) was calculated from a laser diffraction type particle size distribution (“Microtrack MT3000II” manufactured by Microtrac Bell).

<Synthesis of copolymer>
(Synthesis Example 1)
(Synthesis of copolymer 1)
A reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer is charged with 100 parts of methyl ethyl ketone, 90.0 parts of acrylonitrile, 10.0 parts of acrylic acid, and 0.5 parts of 3-mercapto-1,2-propanediol. , Replaced with nitrogen gas. The inside of the reaction vessel is heated to 70 ° C. to prepare a mixture consisting of 10 parts of methyl ethyl ketone and 0.4 part of 2,2'-azobis (2,4-dimethylvaleronitrile) (manufactured by Wako Pure Chemical Industries, Ltd .: V-65). It was dropped into a reaction vessel over a long period of time to carry out a polymerization reaction. After completion of the dropping, the mixture was reacted at 70 ° C. for 1 hour, 0.1 part of V-65 was added, and the reaction was further continued at 70 ° C. for 1 hour to obtain the desired product as a precipitate. After that, it was confirmed by measuring the non-volatile content that the conversion rate exceeded 98%. The product was filtered off by vacuum filtration, washed with 100 parts of ethyl acetate, and dried under reduced pressure to completely remove the solvent to obtain a copolymer (A-1). The weight average molecular weight (Mw) of the copolymer (A-1) was 52,000. The acid value was 78 mgKOH / g.

(Synthesis Examples 2 to 23)
(Synthesis of copolymers 2 to 23)
The copolymers 2 to 23 were produced in the same manner as in Production Example 1 except that the monomers and chain transfer agents used were changed according to Table 1. The weight average molecular weight (Mw) of each dispersant was as shown in Table 1. For the synthesis of the copolymer, Mw was prepared by appropriately changing the addition of the chain transfer agent, the adjustment of the amount of the polymerization initiator, the reaction conditions and the like.

AA: Acrylic acid IA: Itaconic acid SAMA: 2-methacryloyloxyethyl succinate β-CEA: β-carboxyethyl acrylate a-1: Isopropyl alcohol adduct of maleic anhydride (formula (1) below)
a-2: 2-acryloyloxyethyl succinate a-3: Octenyl succinic anhydride adduct of hydroxyethyl acrylate (formula (2) below)
HEA: Hydroxyethyl acrylate DMAEA: Dimethylaminoethyl acrylate BA: Butyl acrylate 2EHA: 2-Ethylhexyl acrylate

(Preparation of conductive material dispersion)
(Example 1-1)
According to the composition shown in Table 2, ion-exchanged water, a copolymer, a base and an antifoaming agent were added to a glass bottle, and the mixture was stirred with a disper until uniform. Then, a conductive material was added, 200 g of zirconia beads having a diameter of 0.5 mm was charged as a dispersion medium, and the dispersion treatment was carried out with a paint shaker for 6 hours to obtain a dispersion. To the obtained dispersion, 10% by mass of an aqueous acetic acid solution, water and an antistatic agent (anionic surfactant; electrostripper ME-2) were appropriately added and stirred, and the mixture was stirred to have a pH of 8.5 and a conductive material content of 0.3%. , A conductive material dispersion (dispersion 1) having an antistatic agent solid content of 3.0% was obtained. The composition in Table 2 is shown so that the total amount of the dispersion treated by the paint shaker is 100 parts.

(Examples 1-2 to 1-33, Comparative Examples 1-1 to 1-4)
According to the composition shown in Table 2, each dispersion (dispersions 1 to 33, comparative dispersions 1 to 4) was obtained in the same manner as in Example 1-1. To the obtained dispersion, 10% by mass of an aqueous acetic acid solution, water and an antistatic agent (anionic surfactant; electrostripper ME-2) were appropriately added and stirred, and the mixture was stirred to have a pH of 8.5 and a conductive material content of 0.3%. , Each conductive material dispersion (dispersions 1-33, comparative dispersions 1 to 4) having an antistatic agent solid content of 3.0% was obtained.

(Example 1-34)
Same as Example 1-1 except that the solid content of the antistatic agent (C) electrostripper ME-2 (anionic surfactant) to be added was changed to 0.6% according to the composition shown in Table 2. A dispersion (dispersion 34) was obtained.

(Example 1-35)
Same as Example 1-1 except that the solid content of the antistatic agent (C) electrostripper ME-2 (anionic surfactant) to be added was changed to 6.0% according to the composition shown in Table 2. The dispersion 35 was obtained.

(Example 1-36)
The dispersion (dispersion 36) was prepared in the same manner as in Example 1-1, except that the antistatic agent (C) to be added was changed to electrostripper QN (cationic surfactant) according to the composition shown in Table 2. Obtained.

(Example 1-37)
The dispersion (dispersion 37) was prepared in the same manner as in Example 1-1, except that the antistatic agent (C) to be added was changed to an electrostripper EA (nonionic surfactant) according to the composition shown in Table 2. Obtained.

(Example 1-38)
A dispersion (dispersion 38) was obtained in the same manner as in Example 1-1, except that the antistatic agent (C) to be added was changed to electrostripper AC (amphoteric surfactant) according to the composition shown in Table 2. rice field.

(Comparative Example 1-5)
According to the composition shown in Table 2, a dispersion (comparative dispersion 5) was obtained in the same manner as in Example 1-1 except that an antistatic agent was not added. However, when the pH of the obtained dispersion was 8.5 or less, it was diluted with water only.

(Method of measuring pH during dispersion process)
The pH during the dispersion step was measured by adjusting the dispersion at 3 hours of the paint shaker to 25 ° C. using a pH meter. The values are shown in Table 3.

(Stability evaluation method for conductive material dispersion)
The stability was evaluated by the change in viscosity of the conductive material dispersion. To measure the viscosity, use a B-type viscometer (“BL” manufactured by Toki Sangyo), stir the dispersion sufficiently with a spatula at a dispersion temperature of 25 ° C, and then set the rotor rotation speed of the B-type viscometer to 60 rpm. I went immediately. The rotor used for the measurement was No. 1 when the viscosity was less than 100 mPa · s. If 1 is 100 or more and less than 500 mPa · s, No. If 2 is 500 or more and less than 2,000 mPa · s, No. If 3 is 2,000 or more and less than 10,000 mPa · s, No. The ones of 4 were used respectively. The viscosity measured within 5 hours after the dispersion was taken as the initial viscosity, and the evaluation was made from the change in the viscosity value after the conductive material dispersion was allowed to stand at 50 ° C. for 10 days and stored. The rate of change was calculated by Eq. (2) and evaluated according to the following criteria based on the calculated results. The evaluation was made on a scale of 〇 (good), Δ (normal), and × (poor). Further, when the viscosity value is ">10", it is expressed as "-" (evaluation is not possible) because the calculation is impossible. The evaluation results are shown in Table 3.
Rate of change (%) = (viscosity after 10 days at 50 ° C.) / (initial viscosity) x 100 ... Equation (2)
◯: Change rate is 80% or more and less than 120% Δ: Change rate is 50% or more and less than 80% or 120% or more and less than 150% ×: Change rate is less than 50% or 150% or more

(Particle size distribution of conductive material dispersion)
The particle size distribution of the conductive material dispersion is obtained by integrating the volume ratio of the particles from the finer particle size in the volume particle size distribution using the laser diffraction type particle size distribution (“Microtrac MT3000II” manufactured by Microtrac Bell). The particle size of 50% was measured to obtain a 50% particle size (D50). The evaluation results are shown in Table 3.

The abbreviations shown in Table 2 mean the following.
<Conductive material>
-TUBALL (80%): OCSiAl, single-wall carbon nanotube, average outer diameter: 1.5 nm, carbon component 80%, specific surface area 490 m ² / g
-TUBALL (93%): OCSiAl, single-wall carbon nanotubes, average outer diameter: 1.5 nm, carbon component 93%, specific surface area 850 m ² / g
<Base>
-LiOH: Lithium hydroxide (manufactured by Kishida Chemical, pKb = -0.36, solubility 22 g / 100 ml)
TEA-OH: 10% aqueous solution of tetraethylammonium hydroxide (manufactured by Tokyo Chemical Industry, pKb = 0.10, solubility 10 g / 100 g or more)
-KOH: Potassium hydroxide (manufactured by Kishida Chemical, pKb = 0.50, solubility 110 g / 100 ml)
-DPA: Dipropylamine (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., pKb = 3.09, solubility 3.5 g / 100 ml)
-NH ₃ : 25% aqueous solution of ammonia (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., pKb = 4.70, solubility 89.9 g / 100 ml)
-Ca (OH) ₂ : Calcium hydroxide (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., pKb = 1.40, solubility 0.17 g / 100 ml)
-TEA: Triethanolamine (Tokyo Chemical Industry, pKb = 6.2, solubility 10 g / 100 ml or more)
<Antistatic agent>
-Anion: Electro stripper ME-2 (Kao's anionic surfactant, sodium alkyl sulfate, solid content 50%)
-Cation: Electro stripper QN (Kao's cationic surfactant, alkyltrimethylammonium salt, solid content 30%)
-Nonion: Electro stripper EA (Kao nonionic surfactant, lauryl diethanolamine, 100% solid content)
-Amphoteric: Electro stripper AC (Kao amphoteric surfactant, imidazoline compound, solid content 25%)

(Preparation of conductive paint and conductive film)
(Example 2-1)
According to the composition shown in Table 4, a conductive material dispersion, a binder for paint, and water were added to the container, and the mixture was stirred with a disper until uniform to obtain paint 1.

(Examples 2-2-42, Comparative Examples 2-1-4)
Each paint (paints 2 to 42, comparative paints 1 to 4) was obtained in the same manner as in Example 2-1 except that the dispersion was changed to the dispersion shown in Table 4.

(Paint evaluation)
With respect to the obtained paint, the paint was further applied to a corona discharge-treated PET film with a bar coater so that the film thickness was 2 μm, set for 30 minutes, dried at 60 ° C. for 30 minutes, and then heated to 140 ° C. After baking for 20 minutes, a test coating film for each paint was prepared, and the paint and its coating film were evaluated as follows. The results are shown in Table 4.
(Compatibility)
The compatibility of the obtained paint with the conductive material dispersion and the paint binder was determined by confirming the density of particles according to JIS K56002-5. Evaluation was performed according to the following criteria. The evaluation was made on a two-point scale of 〇 (good) and × (poor).
◯: Dense less than 20 μm ×: Dense 20 μm or more (transparency)
Regarding the transparency, the total light transmittance of the test coating film applied to the PET film was measured with a haze meter (300A) manufactured by Nippon Denshoku Kogyo. Evaluation was performed according to the following criteria. The evaluation was made on a scale of ⊚ (extremely good), 〇 (good), Δ (normal), and × (poor).
⊚: 80% or more and less than 90% 〇: 70% or more and less than 80% Δ: 60% or more and less than 70% ×: less than 60% (surface resistivity)
Regarding the conductivity, the surface resistivity (Ω / □) of the test coating film applied to the PET film was measured using Mitsubishi Chemical Corporation: Lorester GP (CP-T610). Evaluation was performed according to the following criteria. The evaluation was made on a scale of ⊚ (extremely good), 〇 (good), Δ (normal), and × (poor).
⊚: 1.0 × 10 less than ⁸ 〇: 1.0 × 10 ⁸ or more and less than 1.0 × 10 ¹⁰ Δ: 1.0 × 10 ¹⁰ or more and less than 1.0 × 10 ¹⁴ ×: 1.0 × 10 ¹⁴ or more (Not measurable)
(Appearance of coating film)
Regarding the appearance, the test coating film applied to the PET film was visually observed, and the presence or absence of rough skin, unevenness, and stickiness was confirmed, and the evaluation was performed according to the following criteria.
〇: No skin roughness, unevenness, or stickiness △: Slightly rough skin, unevenness, or stickiness ×: Skin roughness, unevenness, or stickiness

The abbreviations shown in Table 4 mean the following.
-Urethane: Evafanol HA-107C (manufactured by NICCA CHEMICAL, water-based urethane resin, solid content 40%)
-Olefin: Supercron E-415 (Nippon Paper Industries, water-based olefin resin, solid content 30%)

From the results shown in Tables 3 and 4, it is shown that the conductive material dispersion of the present invention is excellent in storage stability, compatibility with a binder for paints, transparency, surface resistivity, and coating film appearance. Was done.

Claims (9)

A conductive material dispersion containing a conductive material, a copolymer (A), a base (B), an antistatic agent (C), and water.
The conductive material contains single-walled carbon nanotubes having an average outer diameter of 1 to 4 nm.
The copolymer (A) contains 10% by mass to 99% by mass of units derived from (meth) acrylonitrile and 1% by mass to 90% by mass of carboxyl group-containing monomer units, based on a total of 100% by mass of all units. It is a copolymer, and the base (B) has a pKb of 5 or less at 25 ° C. in water and a solubility of 1 g / 100 ml or more at 25 ° C. in water, and the copolymer (A) and the base (B). ), The solid content mass ratio (B) / (A) is 0.2 to 1.0. The conductive material dispersion according to claim 1, wherein the copolymer (A) contains 11 to 40% by mass of a carboxyl group-containing monomer unit with respect to 100% by mass of the copolymer (A). The conductive material dispersion according to claim 1 or 2, wherein the pKb of the base (B) is 1 or less. The conductive material dispersion according to any one of claims 1 to 3, wherein the carboxyl group-containing monomer contains acrylic acid and itaconic acid. The conductive material according to any one of claims 1 to 4, wherein the antistatic agent (C) contains at least one selected from the group consisting of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant. Dispersion. The conductive material dispersion according to any one of claims 1 to 5, which comprises an acid. The conductive material dispersion according to any one of claims 1 to 6, wherein the copolymer (A) and the base (B) are contained in a total amount of 20% by mass to 1000% by mass with respect to the conductive material. A conductive coating material comprising the conductive material dispersion according to any one of claims 1 to 7. A conductive coating film, which is a coating film of the conductive coating material according to claim 8.