Polymer dispersants, polymer dispersant compositions, and carbon material dispersions

Abstract

To provide a polymer dispersant for carbon materials that maintains stable dispersibility over a long period of time. [Solution] A polymer dispersant for dispersing carbon materials such as carbon black in a liquid medium, wherein the polymer dispersant comprises 45% by mass or more and 95% by mass or less of the constituent unit (i) represented by the following general formula (1), TIFF2026052894000022.tif33170 (In the above general formula (1), R 1 (1) represents hydrogen, etc., X represents an ethylene group, etc., Y represents an ethylene group, etc., Z represents hydrogen, etc., n represents an arbitrary number of repetitions, and p represents 10 to 100. (2) A polymer having 5% to 30% by mass of constituent units (ii) derived from carboxyl group-containing monomers such as (meth)acrylic acid, and 0% to 20% by mass of constituent units (iii) of vinyl monomers copolymerizable with the aforementioned constituent units (i) and the aforementioned constituent units (ii), with a number average molecular weight of 10,000 to 30,000.

Description

[Technical Field]

[0001] This invention relates to a polymeric dispersant for stably dispersing carbon materials, and to a carbon material dispersion obtained using the polymeric dispersant. [Background technology]

[0002] Carbon materials such as carbon black, carbon fiber, carbon nanotubes, graphite, and graphene (hereinafter also simply referred to as carbon materials) are materials that exhibit various properties such as conductivity and heat transfer due to their six-membered ring graphite structure formed by the covalent bonds of carbon atoms, and methods for utilizing these properties are being investigated in a wide range of fields. For example, focusing on the electrical, thermal, and filler properties of carbon materials, their use in antistatic agents, conductive materials, plastic reinforcements, semiconductors, fuel cell electrodes, and cathode rays in displays is being considered.

[0003] These applications require carbon material dispersions that exhibit good dispersibility of carbon materials and maintain that dispersibility over long periods. However, nano-sized carbon materials have high surface energy and are prone to aggregation due to strong van der Waals forces. Therefore, even when dispersed in a liquid medium, aggregation often occurs immediately.

[0004] Dispersants are generally used to stably disperse carbon materials in a liquid medium. For example, solvent-based dispersions of carbon nanotubes using cationic surfactants such as alkanolamine salts or polymeric dispersants such as styrene-acrylic resins have been proposed (Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2010-174084 [Patent Document 2] Special Publication No. 2013-537570 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, while using low molecular weight surfactants as dispersants makes it possible to disperse carbon materials in a liquid medium, the dispersibility is not always sufficient, and there are also issues such as a tendency for re-aggregation. Furthermore, when using general polymer dispersants, the resulting dispersion tends to exhibit thixotropic properties, and over time, the carbon material may settle or the dispersion may gel.

[0007] This invention has been made in view of the problems of the prior art, and its objective is to provide a polymeric dispersant for carbon materials that exhibits excellent dispersibility even when containing high concentrations of carbon materials, and maintains stable dispersibility over a long period of time. Furthermore, when the polymeric dispersant is used in UV-curable coating agents or inks, the polymeric dispersant has UV-curable groups, eliminating components that are not incorporated into the coating film, and the UV-curable groups cause the polymeric dispersant to act as a crosslinking agent, thereby improving the durability and adhesion of the coating film obtained from the coating agent or ink. Moreover, the invention aims to provide a carbon material dispersion liquid with good dispersibility obtained using the above-mentioned polymeric dispersant. [Means for solving the problem]

[0008] In other words, the present invention provides the following polymer dispersant. [1] A polymeric dispersant for dispersing at least one carbon material selected from the group consisting of carbon black, carbon fiber, carbon nanotubes, graphite, and graphene in a liquid medium, The aforementioned polymer dispersant contains 45% by mass or more and 95% by mass or less of the constituent unit (i) represented by the following general formula (1),

[0009] [ka]

[0010] (In the above general formula (1), R 1 (wherein X represents hydrogen or a methyl group, X represents at least one group selected from the group consisting of ethylene group, methylethylene group, ethyleneaminocarboxy group, and ethyleneoxyethyleneaminocarboxy group, Y represents at least one group selected from the group consisting of ethylene group and methylethylene group, Z represents at least one selected from the group consisting of hydrogen, an alkyl group having 1 to 18 carbon atoms, a (meth)acryloyl group, a (meth)acryloyloxyethylaminocarboxy group, and a (meth)acryloyloxyethoxyethylaminocarboxy group, n represents any number of repetitions, and p represents 10 to 100.) (Meth)acrylic acid, and, A constituent unit (ii) derived from at least one carboxyl group-containing monomer selected from the group consisting of a monoester of at least one polycarboxylic acid compound selected from the group consisting of succinic acid, phthalic acid, trimellitic acid, 1,2-cyclohexanedicarboxylic acid, and 4-cyclohexene-1,2-dicarboxylic acid, is present in an amount of 5% to 30% by mass of at least one hydroxyl group-containing (meth)acrylate selected from the group consisting of 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, and The constituent unit (i) and the constituent unit (iii) of a vinyl monomer copolymerizable with the constituent unit (ii) are present in an amount of 0% by mass or more and 20% by mass or less, A polymer dispersant having a number-average molecular weight of 10,000 or more and 30,000 or less.

[0011] [2] The polymer dispersant according to [1], wherein the polymer dispersant further comprises a constituent unit (iv) derived from a monothiol compound, and the content of the constituent unit (iv) is 0.5 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of the polymer constituent. [3] A polymer dispersant composition comprising a polymer dispersant described in [1] or [2] and an oligomer represented by the following general formula (2).

[0012] [ka]

[0013] (In the above general formula (2), R 2 R represents an alkyl group having 1 to 18 carbon atoms. 3 (wherein is an alkylene group or branched alkylene group having 2 to 4 carbon atoms, W is hydrogen, or at least one group selected from the group consisting of (meth)acryloyloxy group, (meth)acryloyloxyethylaminocarboxy group, and (meth)acryloyloxyethoxyethylaminocarboxy group, and q is 10 to 100.) [4] A carbon material dispersion comprising the polymer dispersant described in [1] or [2], the carbon material, and the liquid medium. [5] The carbon material dispersion according to [4], wherein the liquid medium contains at least one of ultraviolet-curable monomers and oligomers having one or more (meth)acryloyloxy groups. [6] The carbon material dispersion according to [4] or [5], wherein the content of the polymer dispersant per 100 parts by mass of the carbon material is 10 parts by mass or more and 200 parts by mass or less, and the content of the carbon material is 15% by mass or less. [Effects of the Invention]

[0014] According to the present invention, even when a carbon material is contained at a high concentration, a carbon material dispersion liquid excellent in dispersibility and having its dispersibility stably maintained over a long period can be provided. The carbon material dispersion liquid of the present invention is excellent in dispersibility, storage stability, viscosity characteristics, and workability, and a carbon coating film can be formed by coating or the like. Further, by appropriately selecting the carbon material, a film with high transparency can also be formed. Furthermore, even when the content of the polymer dispersant is small, the carbon material is dispersed in a good state, so that it is possible to form a coating film with a high content of the carbon material and utilize the characteristics of the carbon material itself such as conductivity and heat conductivity. Furthermore, the polymer dispersant for dispersing the carbon material has a group that is cured by ultraviolet rays. When used in an ultraviolet curable coating agent or the like, the polymer dispersant can also be cured by ultraviolet rays to enhance the durability of the coating film. In addition, since the polymer dispersant has a large number of ultraviolet curable groups, it functions as a crosslinking agent and can contribute to the durability of the coating film and the adhesion to the substrate in the same manner as described above.

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. <Polymer Dispersant> The polymer dispersant according to the present embodiment is a polymer dispersant that disperses at least one carbon material selected from the group consisting of carbon black, carbon fiber, carbon nanotube, graphite, and graphene in a liquid medium. The polymer dispersant needs to have a structural unit (i) represented by the following general formula (1) in an amount of 45% by mass or more and 95% by mass or less.

[0016]

Chemical formula

[0017] In the general formula (1), R 1X represents hydrogen or a methyl group, X represents at least one group selected from the group consisting of ethylene group, methylethylene group, ethyleneaminocarboxy group, and ethyleneoxyethyleneaminocarboxy group, Y represents at least one group selected from the group consisting of ethylene group and methylethylene group, Z represents at least one selected from the group consisting of hydrogen, an alkyl group having 1 to 18 carbon atoms, a (meth)acryloyl group, a (meth)acryloyloxyethylaminocarboxy group, and a (meth)acryloyloxyethoxyethylaminocarboxy group, n represents any number of repetitions, and p represents 10 to 100.

[0018] The polymer dispersant must contain 5% to 30% by mass of a constituent unit (ii) derived from at least one carboxyl group-containing monomer selected from the group consisting of (meth)acrylic acid and at least one hydroxyl group-containing (meth)acrylate selected from the group of 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, and a monoester of at least one polycarboxylic acid compound selected from succinic acid, phthalic acid, trimellitic acid, 1,2-cyclohexanedicarboxylic acid, and 4-cyclohexene-1,2-dicarboxylic acid.

[0019] The polymer dispersant must contain 0% to 20% by mass of constituent unit (iii) of a vinyl monomer copolymerizable with constituent unit (i) and constituent unit (iii) of a vinyl monomer. Furthermore, the polymer dispersant must be a polymer with a number-average molecular weight of 10,000 or more and 30,000 or less.

[0020] This embodiment is a graft-type polymer having the above configuration, wherein the constituent unit (i) of general formula (1) is included, and the polyalkylene glycol chain represented by [OY]p, which is the constituent of general formula (1), is grafted onto the main chain. Furthermore, the grafted polyalkylene glycol chain is present in a high concentration of 45% to 95% by mass as a component of the polymer dispersant. In addition, the main chain has a monomer having a carboxyl group, that is, the main chain contains an acidic group. By using the polymer dispersant according to this embodiment, carbon materials can be dispersed in a liquid medium with low viscosity and without aggregation during storage. The carboxyl group of the main chain adsorbs to the carbon material, and the grafted polyalkylene glycol chain exhibits steric repulsion between particles, thereby enabling good dispersion of the carbon material in the liquid medium.

[0021] Furthermore, the ends of the polyalkylene glycol chains grafted into the polymer that constitutes the polymer dispersant may have (meth)acryloyloxy groups that can undergo radical polymerization. In such cases, when used in an active energy curable coating, particularly preferably an ultraviolet curable coating, using a monomer or oligomer that can be cured with ultraviolet light or an electron beam as the liquid medium, the polymer dispersant according to this embodiment reacts with the monomers of the liquid medium, and the polymer dispersant itself becomes a component of film formation. Moreover, since the polymer dispersant has multiple (meth)acryloyloxy groups, it acts as a crosslinking agent, improving the durability or physical properties of the film.

[0022] The polymer dispersant according to this embodiment must contain 45% by mass or more and 95% by mass or less of the constituent unit (i) represented by the following general formula (1).

[0023] [ka]

[0024] In general formula (1), R1 X represents hydrogen or a methyl group, X represents at least one group selected from the group consisting of ethylene group, methylethylene group, ethyleneaminocarboxy group, and ethyleneoxyethyleneaminocarboxy group, Y represents at least one group selected from the group consisting of ethylene group and methylethylene group, Z represents at least one selected from the group consisting of hydrogen, an alkyl group having 1 to 18 carbon atoms, a (meth)acryloyl group, a (meth)acryloyloxyethylaminocarboxy group, and a (meth)acryloyloxyethoxyethylaminocarboxy group, n represents any number of repetitions, and p represents 10 to 100.

[0025] This structural unit is a branched graft chain of the polymer that is the polymer dispersant of the present invention. Structurally, it is a polyalkylene glycol chain represented by [OY]p, which is a polyethylene glycol chain, a polypropylene glycol chain, or a polyethylene glycol-polypropylene glycol chain, with the repeating unit p being 10 to 100 and the molecular weight of the graft chain being in the range of 1000 to 4000. If the molecular weight of the graft chain is less than 1000, the grafted molecular weight is small, so sufficient steric repulsion cannot be achieved, and the dispersion stability of the carbon material may not be attainable. On the other hand, if the molecular weight of the graft chain is greater than 4000, the constituent monomer has a large molecular weight, so when manufacturing the polymer dispersant, it may have poor polymerizability and remain, or the viscosity of the dispersion may increase. Particularly preferably, the repeating unit p is 20 to 60, and the molecular weight of the graft chain is 1000 to 3500.

[0026] The polyalkylene glycol chain described above has a polyalkylene glycol chain, and the Z at one end, -OZ, can be hydrogen, a C1-C18 alkyl group, a (meth)acryloyl group, a (meth)acryloyloxyethylaminocarboxy group, or a (meth)acryloyloxyethoxyethylaminocarboxy group. When Z is hydrogen, the end is a hydroxyl group. When Z is a C1-C18 alkyl group, it is an alkoxy group. Specifically, when Z has 1 carbon, it is a methoxy group; when it has 2 carbons, it is an ethoxy group; when it has 4 carbons, it is a butoxy group, etc. When Z is a (meth)acryloyl group, the end is a (meth)acrylate, which is an ester of (meth)acrylic acid. When Z is a (meth)acryloyloxyethylaminocarboxy group or a (meth)acryloyloxyethoxyethylaminocarboxy group, it is a group with an ethylene group or ethoxyethylene group as a linking group via a urethane bond, and a (meth)acrylate at the end.

[0027] When Z is a (meth)acryloyl group, a (meth)acryloyloxyethylaminocarboxyl group, or a (meth)acryloyloxyethoxyethylaminocarboxyl group, it is characterized by having an unsaturated bond at its terminal end and being a radical reactive group. In this case, when the polymer dispersant according to this embodiment is used in an ultraviolet curable coating agent, its (meth)acryloyloxyl groups polymerize, causing the polymer dispersant to react with ultraviolet curable monomers and oligomers contained in the coating agent through radical polymerization, resulting in the polymer dispersant undergoing a crosslinking reaction to become a coating film component. Furthermore, by containing a large amount of its (meth)acryloyloxyl groups, the polymer dispersant according to this embodiment can act as a crosslinking agent, contributing to the durability of the coating film component, such as adhesion and abrasion resistance.

[0028] At one end, X is linked to the main chain via an ester group, with at least one group selected from the group consisting of ethylene, methylethylene, ethyleneaminocarboxy, and ethyleneoxyethyleneaminocarboxy groups. When X is an ethyleneaminocarboxy or ethyleneoxyethyleneaminocarboxy group, a polyalkylene glycol chain is further linked via a urethane bond through an ester group, with the ethylene or ethyleneoxyethylene group acting as a linking group, forming a graft structure.

[0029] This constituent unit (i) is introduced into the polymer dispersant by the following method: When Z is hydrogen or an alkyl group having 1 to 18 carbon atoms, and X is an ethylene group or a methylethylene group, it is obtained by polymerizing a monomer that is a monomer unit corresponding to that constituent unit, which is polyalkylene glycol mono(meth)acrylate or polyalkylene glycol monoalkyl ether (meth)acrylate. Specifically, these monomers include polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, polyethylene glycol monomethyl ether (meth)acrylate, and polyethylene glycol polypropylene glycol monobutyl ether (meth)acrylate.

[0030] When Z is hydrogen or an alkyl group having 1 to 18 carbon atoms, and X is an ethyleneaminocarboxyl group or an ethyleneoxyethyleneaminocarboxyl group, a terminal (meth)acrylate obtained by reacting (meth)acryloyloxyethyl isocyanate or (meth)acryloyloxyethoxyethyl isocyanate with polyethylene glycol polypropylene glycol monohydroxymonamine or polyethylene glycol polypropylene glycol monomethyl ether monoamine, etc., can be polymerized and introduced as constituent unit (i).

[0031] If Z is a (meth)acryloyl group, the monomer unit having a polyalkylene glycol chain with a terminal hydroxyl group obtained above can be polymerized and then reacted with (meth)acrylic acid, (meth)acrylic acid halide, or (meth)acrylic anhydride to obtain it. If Z is a (meth)acryloyloxyethylaminocarboxyl group or a (meth)acryloyloxyethoxyethylaminocarboxyl group, similarly, the monomer unit having a polyalkylene glycol chain with a terminal hydroxyl group obtained above can be polymerized and then reacted with (meth)acryloyloxyethyl isocyanate or (meth)acryloyloxyethoxyethyl isocyanate to introduce constituent unit (i) as a graft chain of a polymer dispersant.

[0032] A key feature of this method is that the amount of raw materials forming these constituent units is set to 45% by mass or more and 95% by mass or less of the total raw materials of the polymer dispersant. By including a large amount of these constituent units, the dispersion stability of carbon materials can be enhanced due to steric hindrance. If the amount is less than 45% by mass, sufficient dispersion stability cannot be achieved, and if it is more than 95% by mass, when attempting to introduce an amount that constitutes these constituent units, the large molecular weight of polypropylene glycol mono(meth)acrylate can lead to poor polymerization during the production of the polymer dispersant, and some units may remain unpolymerized. This amount is preferably 50% by mass or more and 90% by mass or less.

[0033] Next, the constituent unit (ii) of the polymer dispersant according to this embodiment is a constituent unit derived from at least one carboxyl group-containing monomer selected from the group consisting of (meth)acrylic acid and monoesters of polycarboxylic acid compounds. Furthermore, the monoester of the polycarboxylic acid compound is a monoester of at least one hydroxyl group-containing (meth)acrylate selected from the group consisting of 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, and at least one polycarboxylic acid compound selected from the group consisting of succinic acid, phthalic acid, trimellitic acid, 1,2-cyclohexanedicarboxylic acid, and 4-cyclohexene-1,2-dicarboxylic acid. The polymer dispersant according to this embodiment must contain 5% to 30% by mass of this constituent unit (ii). This constituent unit is a monomer unit having an acidic group, and is a group that adsorbs to the carbon material, which is composed of a six-membered carbon aromatic ring, through ionic interactions, hydrogen bonding, and, if its ester residue is an aromatic ring, through ππ stacking.

[0034] Examples of carboxyl group-containing monomers include (meth)acrylic acid, as well as monoesters of at least one polycarboxylic acid compound selected from the group consisting of succinic acid, phthalic acid, trimellitic acid, 1,2-cyclohexanedicarboxylic acid, and 4-cyclohexene-1,2-dicarboxylic acid, of at least one hydroxyl group-containing (meth)acrylate selected from the group consisting of 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. In this carboxyl group-containing monomer, specific examples of compounds in the case of 2-hydroxyethyl (meth)acrylate include (meth)acryloyloxyethyl succinic acid, (meth)acryloyloxyethyl phthalic acid, 1-(meth)acryloyloxyethyl trimellitic acid, 4-(meth)acryloyloxyethyl trimellitic acid, 1,2-cyclohexanedicarboxylic acid (meth)acryloyloxyethyl monoester, and 4-cyclohexene-1,2-dicarboxylic acid (meth)acryloyloxyethyl monoester. In particular, in this embodiment, in order to enhance the adsorption with carbon materials consisting of a six-membered aromatic ring, (meth)acrylates containing an acidic group having an aromatic ring or an unsaturated bond are preferred, and specifically, esterified products with polycarboxylic acids such as phthalic acid, trimellitic acid, or cyclohexenedicarboxylic acid are preferred.

[0035] It is necessary that the amount of raw material forming this constituent unit (ii) be between 5% by mass and 30% by mass of the total raw materials of the polymer dispersant. If the amount of constituent unit (ii) is less than 5% by mass, there will be fewer adsorption groups, and sufficient adsorption may not be achieved, potentially resulting in insufficient dispersion stability. On the other hand, if the amount of constituent unit (ii) is more than 30% by mass, there will be too many hydrophilic carboxyl groups, which may result in poor solubility in the liquid medium when incorporated into a coating agent, making it impossible to mix with the coating agent, or the high carboxyl group content may increase the viscosity of the polymer dispersant solution or dispersion. This amount is preferably between 6% by mass and 25% by mass.

[0036] The polymer dispersant according to this embodiment may consist only of the above-mentioned components, but may also contain a constituent unit (iii) derived from other copolymerizable vinyl monomers. This vinyl monomer is another monomer component used to improve the polymerizability of component (i) and component (ii), to polymerize without leaving any residue of the above-mentioned components, or to adjust the molecular weight or improve adsorption. As this constituent unit (iii), conventionally known radically polymerizable vinyl monomers such as styrene monomers, (meth)acrylates, (meth)acrylamide monomers, and (meth)acrylonitrile monomers can be used. Its composition is the residual amount of components (i) and (ii), and in this embodiment, it is 0% by mass or more and 20% by mass or less.

[0037] In particular, in this embodiment, a monothiol compound is further included as constituent unit (iv), and it is preferable that the content of constituent unit (iv) derived from the monothiol compound is 0.5 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of the polymer constituent. This is a chain transfer agent that adjusts the molecular weight to achieve the molecular weight of this embodiment. Specifically, conventionally known monothiol compounds such as hydroxyethanethiol, dodecanethiol, and glycerol monothiol are used. The amount used is preferably 0.5 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of the polymer constituent. If the amount used is less than 0.5 parts by mass, the molecular weight may become larger than the molecular weight of this embodiment, and if it is more than 5.0 parts by mass, the molecular weight may become too small, or residual thiol odor may remain. The amount used is preferably 0.5 parts by mass or more and 3.0 parts by mass or less.

[0038] The polymer dispersant according to this embodiment must be a polymer with a number-average molecular weight of 10,000 or more and 30,000 or less. If the number-average molecular weight is less than 10,000, the main chain of the graft structure has a small molecular weight, so even if the dispersant is adsorbed, it may be desorbed, and dispersion stability may not be achieved. On the other hand, if the number-average molecular weight is greater than 30,000, the molecular weight is too large and may increase the viscosity of the dispersion. Preferably, the number-average molecular weight is between 12,000 and 27,000. Note that this number-average molecular weight is the number-average molecular weight on a polystyrene basis obtained by gel permeation chromatography.

[0039] The above describes the polymer dispersant according to this embodiment, and there are no particular limitations on its manufacturing method. Preferred examples are described below, but the method is not limited thereto. Solution polymerization is preferred as the manufacturing method for the polymer dispersant according to this embodiment. Using a polymerization solvent, a (meth)acrylate having a polyalkylene glycol chain with a hydroxyl group or alkoxy terminus, in which Z of the constituent unit (i) is hydrogen or an alkyl group having 1 to 18 carbon atoms, and further using constituent unit (iv), thermal polymerization is performed using azo-based or peroxide-based radical polymerization initiator, which is a conventionally known azobisisobutyronitrile or benzoyl peroxide, to polymerize the polymer. Next, it can be used as a polymer dispersant as is, or it can be used as a polymer dispersant according to this embodiment by reacting a reactive monomer such as (meth)acrylic acid, (meth)acryloic acid chloride, (meth)acrylic anhydride, (meth)acryloyloxyethyl isocyanate, or (meth)acryloyloxyethoxyethyl isocyanate with a hydroxyl group terminal where Z is hydrogen, so that the terminal Z becomes a (meth)acryloyl group, (meth)acryloyloxyethylaminocarboxy group, or (meth)acryloyloxyethoxyethyl isocyanate, thereby introducing a radically polymerizable (meth)acryloyl group at the terminal. The reaction between these reactive monomers and the hydroxyl group is not particularly limited, and conventionally known methods can be used.

[0040] The solvent used in this solution polymerization is any conventionally known organic solvent, and is not particularly limited. Specifically, one or more solvents such as hydrocarbon, ketone, ester, glycol, glycol ester, amide, sulfoxide, carbonate, and ionic liquid solvents can be used. While these organic solvents can be used, it is preferable to use a polyglycol-based solvent, such as poly(n=4 or more), which has a relatively large molecular weight and can dissolve the polymer dispersant, as a non-volatile solvent. Specifically, examples include polyethylene glycol monoalkyl ether, polypropylene glycol monoalkyl ether, polyethylene propylene glycol monoalkyl ether, and polyethylene glycol dialkyl ether. By using this polyglycol-based solvent, non-volatility can be achieved.

[0041] Furthermore, in order to further improve its non-volatility, the polymer dispersant according to this embodiment is preferably a polymer dispersant composition comprising an oligomer represented by general formula (2). That is, the polymer dispersant composition according to this embodiment is preferably a solution of the oligomer represented by general formula (2).

[0042] [ka]

[0043] In general formula (2), R 2 R represents an alkyl group having 1 to 18 carbon atoms. 3 represents an alkylene group or branched alkylene group having 2 to 4 carbon atoms, W represents hydrogen or at least one group selected from the group consisting of (meth)acryloyloxy group, (meth)acryloyloxyethylaminocarboxy group, and (meth)acryloyloxyethoxyethylaminocarboxy group, and q represents 10 to 100.

[0044] When W is hydrogen, the polymer dispersant can be obtained by polymerizing it as described above, using the corresponding polyalkylene glycol monoalkyl ether as the solvent. Furthermore, when introducing an unsaturated group such as a (meth)acryloyl group, a (meth)acryloyloxyethylaminocarboxyl group, or a (meth)acryloyloxyethoxyethylaminocarboxyl group into the polymer dispersant, an unsaturated bond can also be introduced to the hydroxyl group terminus of the oligomer, which is the solvent, in the same manner as the polymer dispersant, to obtain a solution of the oligomer into which the unsaturated group represented by general formula (2) has been introduced.

[0045] The oligomer represented by general formula (2) is R 3 The poly(q=10~100)alkylene glycol of ethylene, propylene, methylethylene, or tetramethylene groups, with one end being an alkyl ether having a carbon atom number ranging from a methyl group to an octadecyl group. If W is hydrogen, the end is a hydroxyl group, or the oligomer is formed by reacting the hydroxyl group with the aforementioned reactive monomer to introduce a (meth)acryloyl group, (meth)acryloyloxyethylaminocarboxy group, or (meth)acryloyloxyethoxyethylaminocarboxy group. When the end is a (meth)acryloyl group, (meth)acryloyloxyethylaminocarboxy group, or (meth)acryloyloxyethoxyethylaminocarboxy group, it is characterized by having a radical polymerizable (meth)acryloyloxy group, which makes it a component of the coating film.

[0046] The polyalkylene glycol monoalkyl ether used has a repeating unit q of 10 to 100. If it is less than 10, it may contain oligomeric molecular weights that have a flash point, and if it is greater than 100, the viscosity may become too high and polymerization may be incomplete. The repeating unit q is preferably between 20 and 50. Specifically, examples of this polyalkylene glycol monoalkyl ether include polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether, and polyethylene glycol polypropylene glycol monobutyl ether. Polyethylene glycol polypropylene glycol monobutyl ether is preferred because it is liquid at room temperature and there are many commercially available varieties with a wide molecular weight range.

[0047] In the composition of the polymer dispersant and the monomer represented by general formula (2) according to this embodiment (polymer dispersant composition according to this embodiment), the content of the polymer dispersant is arbitrary and not particularly limited. However, the content of the polymer dispersant is preferably 15% by mass or more and 70% by mass or less, based on the total amount of the polymer dispersant composition.

[0048] <Carbon materials> The polymer dispersant according to this embodiment is a polymer dispersant that disperses at least one carbon material selected from the group consisting of carbon black, carbon fiber, carbon nanotube, graphite, and graphene in a liquid medium. The carbon material used in this embodiment is at least one carbon material selected from the group consisting of carbon black, carbon fiber, carbon nanotube, graphite, and graphene. There are no particular limitations on the details thereof. For example, as carbon black, acetylene black, furnace black, thermal black, and Ketjen black can be used. There are no particular limitations on its structure, oil absorption, specific surface area, or surface modification such as oxidation, and various conventionally known carbon blacks can be used.

[0049] Examples of carbon fibers include PAN-based carbon fibers made from polyacrylonitrile, pitch-based carbon fibers made from pitches, and recycled products thereof. In particular, so-called carbon nanofibers, which have a nano-sized fiber diameter and a tubular shape formed by winding a six-membered ring graphite structure, and carbon nanotubes, which have a single-nanometer diameter, can be used. For carbon nanofibers and carbon nanotubes, multi-walled or single-walled structures can be used.

[0050] Graphite and graphene, which are nanosheets consisting of one to several carbon layers, can be used. The particle size, fiber diameter, fiber length, shape, and manufacturing method of these carbon materials are not limited. Mixtures thereof can also be used. Furthermore, other metals or metal salts such as platinum and palladium may be doped into the carbon material.

[0051] Furthermore, the surfaces of these carbon materials may be surface-modified by oxidation, plasma treatment, radiation treatment, corona treatment, or coupling treatment.

[0052] <Carbon material dispersion> The invention according to this embodiment is characterized by a carbon material dispersion (hereinafter also simply referred to as dispersion) containing the carbon material, liquid medium, and polymer dispersant, wherein the polymer dispersant is the polymer dispersant according to this embodiment. As the liquid medium, the conventionally known organic solvents described above can be used, and when the carbon material dispersion is used as an ultraviolet-curable coating agent, a mixture containing at least one of ultraviolet-curable monomers and oligomers having one or more (meth)acryloyloxy groups is used.

[0053] As the organic solvent, one or more conventionally known organic solvents are used, such as hydrocarbon-based, alcohol-based, ketone-based, ester-based, ether-based, glycol-based, glycol ether-based, glycol ester-based, amide-based, sulfoxide-based, carbonate-based, and ionic liquid-based solvents. Water may also be used in combination.

[0054] The mixture containing at least one of the UV-curable monomers and oligomers can be any conventionally known material and is not particularly limited. Examples of curing components include monofunctional monomers, polyfunctional monomers, photocurable oligomers, or photocurable polymers. Specifically, examples of monofunctional monomers include radical polymerizable monomers such as (meth)acrylate-based, (meth)acrylamide-based, (meth)crilonitrile-based, vinyl alkanoate-based, or styrene-based monomers.

[0055] Examples of polyfunctional monomers or photocurable oligomers include poly(meth)acrylates of polyhydric alcohols such as ethylene glycol, trimethylolpropane, and neopentyl glycol; and poly(meth)acrylates of polymers such as polyurethane polyols, polyester polyols, polycarbonate polyols, and polyacrylate polyols.

[0056] The above describes the composition of the carbon material dispersion according to this embodiment. Preferably, the mass ratio of the carbon material to the polymer dispersant according to this embodiment is 10 parts by mass or more and 200 parts by mass or less per 100 parts by mass of carbon material, and the carbon material content in the dispersion is 15% by mass or less. If the amount of polymer dispersant is excessively small relative to the carbon material, sufficient dispersion performance cannot be obtained. On the other hand, if the amount of polymer dispersant is excessively large relative to the carbon material, the dispersion may become thicker, and the proportion of carbon material in the solid content will be relatively low, which is undesirable. From this viewpoint, it is more preferable that the amount of polymer dispersant per 100 parts by mass of carbon material in the carbon material dispersion according to this embodiment is 20 parts by mass or more and 150 parts by mass or less, and particularly preferable that it is 30 parts by mass or more and 100 parts by mass or less. Furthermore, it is more preferable that the carbon material content in the carbon material dispersion is 0.01% by mass or more and 10% by mass or less. By using the polymer dispersant according to this embodiment, and more preferably by blending the carbon material and the polymer dispersant in the aforementioned mass ratio, a more stable dispersion of carbon material can be obtained.

[0057] The carbon material dispersion according to this embodiment may contain other components in addition to the carbon material, polymer dispersant, and liquid medium described above. Specifically, it may contain photopolymerization initiators, light stabilizers, antioxidants, dyes, pigments, fluorescent whitening agents, leveling agents, defoaming agents, lubricants, thickeners, antistatic agents, surfactants, silane coupling agents, anti-yellowing agents, bluing agents, infrared absorbers, adhesion promoters, antifouling agents, water repellents, curable catalysts, inorganic fillers, and metal fine particles. Examples of inorganic fillers include silica.

[0058] The physical properties of the carbon material dispersion according to this embodiment are conventionally known and not particularly limited. From a practical standpoint, the viscosity of the carbon material dispersion is preferably 3 mPa·s or more and 100 mPa·s or less.

[0059] The method for dispersing the carbon material using the polymer dispersant described above when preparing the carbon material dispersion according to this embodiment is not limited to conventionally known methods. For example, dispersion methods such as disperser stirring, kneading with a three-roll machine, ultrasonic dispersion, bead mill dispersion, emulsifier, or dispersion using a high-pressure homogenizer can be used. However, bead mill dispersion, ultrasonic dispersion, or high-pressure homogenizer are preferred due to their high dispersion effect. The carbon material dispersion according to this embodiment can be easily prepared by mixing at least the carbon material, a liquid medium, and a polymer dispersant and performing a dispersion treatment.

[0060] The dispersibility of the carbon material in the carbon material dispersion according to this embodiment can be confirmed by measuring the absorbance of the dispersion using a spectrophotometer, as described below. First, several samples of dispersions of carbon material at very low concentrations of known concentration are prepared, and the absorbance at a specific wavelength is measured to create a calibration curve of absorbance against concentration. Next, the carbon material, liquid medium, and polymer dispersant are mixed, dispersed using a predetermined dispersion method, and then centrifuged to separate any undispersible carbon material by sedimentation. The supernatant is diluted to a concentration at which absorbance can be measured, and the absorbance is measured. The concentration is then calculated from the calibration curve. The dispersibility can be evaluated by the concentration of the obtained dispersion or by comparing the amount charged with the concentration of the dispersion. Alternatively, the carbon material dispersion after centrifugation can be left to stand for a long period of time to check for the presence or absence of aggregates. Alternatively, the dispersion can be dropped onto a glass plate or the like and its state can be checked with an electron microscope, or it can be coated to create a film and its electrical conductivity can be measured. When a predetermined conductivity is reached, it can be determined that good dispersion has been achieved.

[0061] In the use of the carbon material dispersion according to this embodiment, it can be used in applications such as paints, inks, or plastics in which carbon materials are dispersed, and is expected to be used as a conductive material or thermal conductive agent, as well as an antistatic material. The production of paints or inks in which carbon materials are dispersed can be achieved by adding solvents, resins, additives, etc. to the carbon material dispersion according to this embodiment to form a paint or ink composition, or by adding the carbon material dispersion to commercially available paints or inks. [Examples]

[0062] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" and "%" are based on mass unless otherwise specified.

[0063] <Manufacturing of polymer dispersant compositions> (Synthesis Example 1) (a) Synthesis of macromonomers 100 parts (0.045 mol) of terminally aminated polypropylene glycol polyethylene glycol (PPG / PEG) monomethyl ether copolymer (trade name "Jeffermin M2005", Huntsman, molecular weight 2222.2, hereinafter abbreviated as M2005) were added to a reaction apparatus equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube. 6.98 parts (0.045 mol) of 2-isocyanatoethyl methacrylate (trade name "Karenz MOI", Resonaq, hereinafter abbreviated as MOI) were added dropwise to the reaction vessel over 30 minutes while water cooling. After the addition, a portion of the reaction solution was sampled, and infrared spectroscopy (hereinafter abbreviated as IR) confirmed that the isocyanate group derived from MOI had almost completely disappeared and that a urea bond had been formed. This confirmed the formation of a macromonomer. The number-average molecular weight of the macromonomer, measured using gel permeation chromatography with tetrahydrofuran as the developing solvent, was 3,400 in polystyrene terms, and the degree of dispersion (PDI = Mw (weight-average molecular weight) / Mn (number-average molecular weight)) was 1.16. Furthermore, an attempt was made to measure the amine value using a potentiometric automatic titrator with a 0.1 mol / L 2-propanolic hydrochloric acid solution, but the amine value of the macromonomer could not be measured. This also confirmed that the reaction between M2005 and MOI was complete. The obtained macromonomer is referred to as MC-1.

[0064] (b) Polymer dispersants (polymer synthesis) To the above reaction vessel, 46.2 parts of polypropylene glycol polyethylene glycol monobutyl ether copolymer (trade name "Unilube 50MB-26", manufactured by NOF Corporation, EO / PO repeat number EO / PO=17 / 17, molecular weight 2,048, hereinafter abbreviated as 50MB-26), 20.0 parts of methyl methacrylate (hereinafter abbreviated as MMA), 10.0 parts of methacrylic acid (hereinafter abbreviated as MAA), and 1.5 parts of 1-thioglycerol (hereinafter abbreviated as TGL) were added. After heating to 70°C while bubbling with nitrogen, 0.1 parts of 2,2'-azobis(dimethyl isobutyrate) (trade name "V-601", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., hereinafter abbreviated as V-601) were added and polymerization was carried out for 4 hours. Another 0.1 parts of V-601 were added and polymerization was carried out at 70°C for 4 hours to form a polymer that is a polymeric dispersant, and polymeric dispersant composition G-1 was obtained. The formed polymer had a manganese content of 14,100 and a PDI of 2.03. The theoretical solid content, determined from the mixing ratio, was 75%, and this value represents the content of the polymeric dispersant. The theoretical solid content of the polymeric dispersant, determined from the mixing ratio, was calculated by taking the solid content of the components excluding the solvent 50MB-26 as the solid content and dividing by the total amount. The theoretical solid content was calculated in the same manner for subsequent steps. The theoretical acid value, calculated from the mixing ratio, was 47.6 mgKOH / g. The theoretical acid value was calculated using the following formula as follows. First, calculating the proportion of MAA in the polymer, we get 10.0 × 100 / 136.98 = 7.30. Molecular weight of MAA: 86.09 Therefore, the acid value is as follows: (7.30 / 86.09)×56.11×1000 / 100=47.6mgKOH / g Molecular weight of KOH: 56.11

[0065] (Synthesis Examples 2-3) Polymer dispersant compositions G-2 to G-3 were obtained in the same manner as in Example 1 described above, except for the formulation shown in Table 1. The meanings of the abbreviations in Table 1 are as follows. • 50MB-11: Polypropylene glycol polyethylene glycol monobutyl ether, product name "Unilube 50MB-11", manufactured by NOF Corporation. • M41: Terminally aminated polypropylene glycol polyethylene glycol monomethyl ether copolymer, trade name "Genamine M41 / 2000", manufactured by Clariant. • M1000: End-terminated amination polypropylene glycol polyethylene glycol monomethyl ether copolymer, trade name "Jeffermin M1000", manufactured by Huntsman. AA: Acrylic acid BzMA: Benzyl methacrylate • CHMA: Cyclohexyl methacrylate HOMS: 2-methacryloyloxyethyl succinate

[0066] Table 1 shows the formulation, composition, and physical properties of polymer dispersant compositions G-1 to G-3 obtained in Synthesis Examples 1 to 3.

[0067] [Table 1]

[0068] (Synthesis Example 4) In a reaction vessel similar to that used in Synthesis Example 1, 100 parts of methacrylate-modified polypropylene glycol (trade name "Bremmer PP-2000D", manufactured by NOF Corporation, molecular weight 2046, hereinafter abbreviated as PP2000D), 37.7 parts of 50MB-26, 5.0 parts of MMA, 7.0 parts of MAA, and 1.5 parts of TGL were added. After heating to 70°C while bubbling with nitrogen, 0.1 parts of V-601 were added and polymerization was carried out for 4 hours. Another 0.1 parts of V-601 were added and polymerization was carried out at 70°C for 4 hours to form a polymer that serves as a polymeric dispersant, obtaining polymeric dispersant composition G-4. The Mn of the polymer was 15,600 and the PDI was 2.06.

[0069] (Synthesis examples 5-6) Polymer dispersant compositions G-5 to G-6 were obtained in the same manner as in Example 4 described above, except for the formulation shown in Table 2. The meanings of the abbreviations in Table 2 are as follows. • MB-38: Polypropylene glycol monobutyl ether, product name "Unilube MB-38", manufactured by NOF Corporation. • AP1000D: Methacrylic-modified polypropylene glycol with one end, trade name "Bremmer PP-1000D", manufactured by NOF Corporation. PAMA: 1-methacryloyloxyethyl phthalate • TMAMA: Addition reaction product of trimellitic anhydride and 2-hydroxyethyl methacrylate EHMA: 2-ethylhexyl methacrylate

[0070] Table 1 shows the formulation, composition, and physical properties of polymer dispersant compositions G-4 to G-6 obtained in synthesis examples 4 to 6.

[0071] [Table 2]

[0072] (Synthesis Example 7) a) Polymerization In a reaction apparatus similar to that used in Synthesis Example 1, 45.7 parts (0.0223 mol) of 50MB-26, 100 parts (0.0489 mol) of PP2000D, 15.0 parts of MMA, 10.0 parts of MAA, and 2.0 parts of 1-dodecanethiol (hereinafter abbreviated as LSH) were added, and the mixture was heated to 70°C while bubbling nitrogen gas. When 70°C was reached, 0.1 parts of V601 were added as a polymerization initiator, and polymerization was carried out at 70°C for 4 hours. Further polymerization of 0.1 parts of V-601 was carried out at 70°C for another 4 hours to obtain a polymer solution. When the obtained polymer was sampled and its molecular weight was measured, the Mn was 23,300 and the PDI was 1.75.

[0073] b) Introduction of unsaturated groups Next, 11.0 parts (0.0712 mol, the sum of moles of 50MB-26 and PP2000D) of methacrylic anhydride (molecular weight: 154.17, hereinafter abbreviated as MAN) were added to the polymer solution obtained above, and the mixture was reacted at 70°C for 5 hours. When a sample was taken and IR measurement was performed, the peak originating from the acid anhydride had disappeared, confirming that the reaction was complete. Thus, a polymer solution was obtained in which unsaturated groups were introduced at the ends of the side chain polymer and at the ends of 50MB-26. The obtained polymer dispersant composition is referred to as G-7. The theoretical solid content (content of polymer dispersant) was calculated by dividing the solid content by the total mass, with the methacrylic acid produced as a by-product from the reaction of MAN with 50MB-26 considered as non-solid content.

[0074] (Synthesis examples 8-9) A polymer solution containing the polymer dispersant of the present invention was obtained in the same manner as in Synthesis Example 7 described above, except that the composition was as shown in Table 3. The meaning of the abbreviations in Table 3 is as follows. • CHDMA: Addition reaction product of 4-cyclohexene-1,2-dicarboxylic acid and 2-hydroxyethyl methacrylate St: Styrene • AOI: 2-isocyanatoethyl acrylate (trade name "Kalenz AOI", manufactured by Resonaq, molecular weight 141.13) DOS: Tin dioctanoate

[0075] Table 3 shows the formulation, composition, and physical properties of polymer dispersant compositions G-7 to G-9 obtained in synthesis examples 7 to 9.

[0076] [Table 3]

[0077] (Comparative Synthesis Example 1) Polymer dispersant composition RG-1 was obtained in the same manner as in Synthesis Example 1 described above, except for the formulation shown in Table 4. The formulation, composition, and physical properties of polymer dispersant composition RG-1 obtained in Comparative Synthesis Example 1 are shown in Table 4.

[0078] [Table 4]

[0079] (Comparative Synthesis Example 2) Polymer dispersant composition RG-2 was obtained in the same manner as in Synthesis Example 4 described above, except for the formulation shown in Table 5. The formulation, composition, and physical properties of polymer dispersant composition RG-2 obtained in Comparative Synthesis Example 2 are shown in Table 5.

[0080] [Table 5]

[0081] (Comparative Synthesis Example 3) Polymer dispersant composition RG-3 was obtained in the same manner as in Synthesis Example 7 described above, except for the formulation shown in Table 6. The formulation, composition, and physical properties of polymer dispersant composition RG-3 obtained in Comparative Synthesis Example 3 are shown in Table 6.

[0082] [Table 6]

[0083] <Preparation of carbon nanotube (CNT) dispersion> (Example 1) 0.2 parts of single-walled carbon nanotubes (Tuball, manufactured by OCSiAl, average diameter: 1.6±0.4 nm, average length: 5 μm, hereinafter abbreviated as Tubal), 99.53 parts of methyl ethyl ketone (hereinafter abbreviated as MEK), 0.27 parts of polymer dispersant composition G-1 (theoretical solid content 75.0%), and 180 parts of zirconia beads (diameter 0.8 mmφ) were placed in a resin container. The CNTs were wet but settled at the bottom of the container, with a transparent layer at the top. When dispersed using ScanDex for 60 minutes, the liquid turned uniformly black, indicating that the aggregated state of the CNTs had broken down. Next, the CNTs that were not sufficiently dispersed were separated by centrifugation, and the supernatant liquid was taken out as CNT dispersion-1.

[0084] (Examples 2-15, Comparative Examples 1-4) Except for the formulation shown in Table 7, CNT dispersions - 2 to CNT dispersions - 19 were prepared in the same manner as in Example 1 described above. The meanings of the abbreviations in Table 7 are shown below. ·MWCNT: (manufactured by Hamamatsu Carbonix Co., multi - wall carbon nanotubes, average diameter: 10 - 40 nm, average length: 1,000 μm ± 500 μm) ·SG101: (trade name "SG - 101", manufactured by Nippon Zeon Co., single - wall carbon nanotubes, average diameter: 3 - 5 nm, average length: 100 - 600 μm) ·100T: (trade name "K - nanos100T", manufactured by KUMHO, average diameter: 11 - 13 nm, average length: 40 - 50 μm)

[0085]

Table 7

[0086] <Evaluation of CNT Dispersions> Using an E - type viscometer (measurement conditions: 25°C, rotor rotation speed 100 rpm), the viscosities of the CNT dispersions at 25°C immediately after dispersion (initial) and after standing for 10 days were measured. Then, based on the initial viscosity, the change rate of the viscosity after standing for 10 days (viscosity change rate (%)) was calculated, and the viscosity stability of the CNT dispersions was evaluated according to the following evaluation criteria. Furthermore, the state of the CNT dispersions after standing for 10 days was observed by optical microscopy (200 times magnification) to confirm the presence or absence of aggregates. [[ID=XX]] ◎: The viscosity change rate was less than 5%. 〇: The viscosity change rate was 5% or more and less than 10%. ×: The viscosity change rate was 10% or more.

[0087] Furthermore, the CNT concentration of the CNT dispersion after centrifugation was measured. A spectrophotometer was used to measure the CNT concentration. Specifically, a calibration curve was created by measuring the absorbance of samples with known CNT concentrations. Then, the absorbance of samples diluted to a concentration where absorbance could be measured was measured, and the CNT concentration of the sample was calculated from the calibration curve. The ratio (%) of the CNT concentration after centrifugation to the designed CNT concentration was calculated as "dispersion stability (%)". The closer the dispersion stability is to 100%, the better the dispersibility of the CNTs. The evaluation results of the CNT dispersion are shown in Table 8.

[0088] [Table 8]

[0089] Examples 1 to 15 were CNT dispersions prepared using the polymer dispersant composition of the present invention. All of them exhibited excellent viscosity stability and dispersion stability, and no aggregates were observed after standing for 10 days. On the other hand, in Comparative Examples 1 to 4, since dispersion was performed using polymer dispersant compositions outside the scope of the present invention, at least one of the viscosity stability and dispersion stability was poor, and aggregates were also observed.

[0090] <Preparation of carbon black (CB) dispersion> (Example 16) 3.0 parts of carbon black (product name "Li-435", manufactured by Denka Co., Ltd., acetylene black), 3.0 parts of MEK, 4.0 parts of polymer dispersant composition G-1 (theoretical solids content 75.0%), and 180 parts of zirconia beads (diameter 0.8 mmφ) were placed in a resin container. The CB was wet but settled at the bottom of the container, with a clear layer at the top. Dispersion treatment was performed using ScanDex for 60 minutes, after which the liquid turned uniformly black and the aggregated state of the CB was broken down. Next, the CB that was not sufficiently dispersed was separated by centrifugation, and the supernatant liquid was taken out as CB dispersion-1.

[0091] (Examples 17-21, Comparative Examples 5-7) CB dispersions - 2 to CB dispersions - 9 were prepared in the same manner as in Example 16 described above, except that the formulation shown in Table 9 was used.

[0092]

Table 9

[0093] <Evaluation of CB Dispersions> Using an E-type viscometer (measurement conditions: 25°C, rotor rotation speed 100 rpm), the viscosities of the CB dispersions at 25°C immediately after dispersion (initial) and after standing for 10 days were measured. Then, the change rate of the viscosity after standing for 10 days (viscosity change rate (%)) based on the initial viscosity was calculated, and the viscosity stability of the CB dispersions was evaluated according to the following evaluation criteria. ◎: The viscosity change rate was less than 5%. 〇: The viscosity change rate was 5% or more and less than 10%. ×: The viscosity change rate was 10% or more.

[0094] Furthermore, the state of the CB dispersions after standing for 10 days was observed by optical microscopy (200 times magnification) to confirm the presence or absence of aggregates. The evaluation results of the CB dispersions are shown in Table 10.

[0095]

Table 10

[0096] All of the CB dispersions of Examples 16 to 21 dispersed using the polymer dispersant composition of the present invention had excellent viscosity stability, and no aggregates were observed after standing for 10 days. On the other hand, the CB dispersions of Comparative Examples 5 to 7 had poor viscosity stability, and some aggregates were also confirmed.

[0097] <Preparation of Nanographene (NG) Dispersions> (Example 22) Nanographene (average diameter: 5 μm, average thickness: 6 - 8 nm), 5.0 parts, 85.0 parts of propylene glycol monomethyl ether acetate (hereinafter abbreviated as PGMAc), and 6.7 parts of G-2 (theoretical solid content 75.0%) were charged into a 200 mL polycup. Next, a stirrer was placed into the polycup and stirred with a magnetic stirrer. While cooling with water, ultrasonic waves were irradiated for 60 minutes using an ultrasonic disperser with an output of 300 W. After the ultrasonic irradiation treatment, the obtained dispersion was a viscous liquid. The obtained dispersion was designated as NG dispersion liquid - 1.

[0098] [[ID=!3]] (Examples 22 - 24, Comparative Examples 8 - 10) NG dispersion liquids - 2 to NG dispersion liquids - 6 were prepared in the same manner as in Example 22 described above, except that the formulations shown in Table 11 were used.

[0099]

Table 11

[0100] <Evaluation of NG dispersion liquid> Using an E-type viscometer (measurement conditions: 25 °C, rotor rotation speed 100 rpm), the viscosities of the CB dispersion liquid at 25 °C immediately after dispersion (initial) and after standing for 10 days were measured. Then, based on the initial viscosity, the change rate of the viscosity after standing for 10 days (viscosity change rate (%)) was calculated, and the viscosity stability of the NG dispersion liquid was evaluated according to the following evaluation criteria. ◎: The viscosity change rate was less than 5%. 〇: The viscosity change rate was 5% or more and less than 10%. ×: The viscosity change rate was 10% or more.

[0101] Furthermore, the state of the NG dispersion liquid after standing for 10 days was observed with an optical microscope (200 times magnification) to confirm the presence or absence of aggregates. The evaluation results of the NG dispersion liquid are shown in Table 12.

[0102]

Table 12

[0103] The NG dispersion liquids dispersed using the polymer dispersant composition of the present invention all had excellent viscosity stability, and no aggregates were observed after standing for 10 days. On the other hand, the NG dispersion liquids of Comparative Examples 8 to 10 had poor viscosity stability, and aggregates were also confirmed.

[0104] <Manufacture of paint composition> (Production Example ①) 50 parts of the CNT dispersion liquid - 1 obtained in Example ① was diluted with 100 parts of tripropylene glycol diacrylate (hereinafter abbreviated as TPGDA), and 4.0 parts of (1 - hydroxycyclohexyl phenyl ketone, trade name "Irgacure 184", manufactured by IGM Resins) was added as a photoinitiator, and mixed until uniform to obtain a paint composition - 1.

[0105] (Production Examples 2 to 24, Comparative Production Examples 1 to 3) Paint compositions - 2 to paint composition - 27 were obtained in the same manner as in Production Example ① except that the composition shown in Table 13 was used.

[0106]

Table 13

[0107] <Manufacture of cured film> (Application Example ①) The paint composition - 1 was applied to the treated surface of an easily - adherent PET film (Toyobo: A4160) with a D - bar #14 to a dry film thickness of 14 g / m 2 and dried for 40 seconds using a dryer at 100 °C. Then, a cured film was obtained by irradiating UV light at 5 m / min and 1 - pass conditions using an 80 W / cm high - pressure mercury lamp.

[0108] (Application Examples 2 to 24, Comparative Application Examples 1 to 3) Cured films were obtained in the same manner as in Application Example ① using paint compositions - 2 to paint composition - 27 instead of the paint composition - 1 of Application Example ①.

[0109] ​​​​Using a JSPS-type robustness tester (manufactured by Yasuda Seiki Co., Ltd.), a No. 3 metal width was attached to a 1cm x 1cm flat friction plate, and a sliding performance test was conducted under conditions of a 500g load and 60 reciprocations / minute. The film surface after friction was visually observed and evaluated on a 5-point scale (poor 1 to excellent 5).

[0110] (Antiblocking test) The resulting cured film was cut to a size of 4cm x 4cm, and the untreated side of a PET film cut to the same size was placed on top of it and subjected to a blocking test at 4kg / cm². 2 The load was applied and the test was conducted for 24 hours in a 40°C atmosphere. After the test, the performance was evaluated according to the evaluation criteria shown below. The results of the sliding performance test and the antiblocking performance test are shown in Table 14. ○: It peeled off easily without applying any force. △: There was a slight delay before delamination, but the interface did not get wet. ×: No delamination occurred, and the interface remained wet.

[0111] [Table 14]

[0112] Application Examples 1 to 24, prepared using polymer solutions containing the polymer dispersant of the present invention, exhibited excellent curability, achieved a sliding properties score of 4 or higher, and demonstrated good antiblocking properties. On the other hand, for comparative application example 1, the sliding properties test result was 3 and the antiblocking properties test result was 4, which are relatively good. This is thought to be because an unsaturated group was introduced into the polymer dispersant, resulting in a film that was somewhat strong. However, it was confirmed that the results were inferior to those of application examples 1 to 24. Furthermore, for comparative application examples 2 and 3, the sliding properties test score was 2 or less, and the antiblocking properties test was also found to be poor. [Industrial applicability]

[0113] The carbon material dispersion of the present invention exhibits high stability and high dispersibility, and paints, inks, coatings, plastic molded products, etc. obtained from this carbon dispersion can fully exhibit the properties of the carbon material, such as high conductivity or high heat transfer, and are suitable for various applications of the carbon material, such as battery materials, electronic component trays, IC chip covers, electromagnetic shields, automotive components, or robot parts.

Claims

1. A polymeric dispersant for dispersing at least one carbon material selected from the group consisting of carbon black, carbon fiber, carbon nanotubes, graphite, and graphene in a liquid medium, The polymer dispersant contains 45% by mass or more and 95% by mass or less of the constituent unit (i) represented by the following general formula (1), 【Chemistry 1】 (In the above general formula (1), R １ X represents hydrogen or a methyl group, X represents at least one group selected from the group consisting of ethylene group, methylethylene group, ethyleneaminocarboxy group, and ethyleneoxyethyleneaminocarboxy group, Y represents at least one group selected from the group consisting of ethylene group and methylethylene group, Z represents at least one selected from the group consisting of hydrogen, a C1-C18 alkyl group, (meth)acryloyl group, (meth)acryloyloxyethylaminocarboxy group, and (meth)acryloyloxyethoxyethylaminocarboxy group, n represents any number of repetitions, and p represents 10-100. (Meth)acrylic acid, and, A constituent unit (ii) derived from at least one carboxyl group-containing monomer selected from the group consisting of a monoester of at least one polycarboxylic acid compound selected from the group consisting of succinic acid, phthalic acid, trimellitic acid, 1,2-cyclohexanedicarboxylic acid, and 4-cyclohexene-1,2-dicarboxylic acid, is present in an amount of 5% to 30% by mass of at least one hydroxyl group-containing (meth)acrylate selected from the group consisting of 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, and The constituent unit (i) and the constituent unit (iii) of a vinyl monomer copolymerizable with the constituent unit (ii) are present in an amount of 0% by mass or more and 20% by mass or less. A polymer dispersant having a number-average molecular weight of 10,000 or more and 30,000 or less.

2. The polymer dispersant according to claim 1, wherein the polymer dispersant further comprises a constituent unit (iv) derived from a monothiol compound, and the content of the constituent unit (iv) is 0.5 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of the polymer constituent.

3. A polymer dispersant composition comprising a polymer dispersant according to claim 1 or claim 2 and an oligomer represented by the following general formula (2). 【Chemistry 2】 (In the above general formula (2), R ２ R represents an alkyl group having 1 to 18 carbon atoms. ３ (wherein is an alkylene group or branched alkylene group having 2 to 4 carbon atoms, W is hydrogen, or at least one group selected from the group consisting of (meth)acryloyloxy group, (meth)acryloyloxyethylaminocarboxy group, and (meth)acryloyloxyethoxyethylaminocarboxy group, and q is 10 to 100.)

4. A carbon material dispersion comprising the polymer dispersant according to claim 1 or claim 2, the carbon material, and the liquid medium.

5. The carbon material dispersion according to claim 4, wherein the liquid medium contains at least one of ultraviolet-curable monomers and oligomers having one or more (meth)acryloyloxy groups.

6. The carbon material dispersion according to claim 4, wherein the content of the polymer dispersant is 10 parts by mass or more and 200 parts by mass or less per 100 parts by mass of the carbon material, and the content of the carbon material is 15% by mass or less.

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