WO2021140965A1 - Paint composition and production method therefor - Google Patents

Abstract

The present invention pertains to a paint composition comprising activated carbon and a liquid dispersion medium, wherein the activated carbon has a central particle diameter D₅₀ of at most 1,000 nm, and the content of the activated carbon is 1-10 mass% with respect to the total mass of the paint composition.

Description

Compositions for paints and methods for producing them

The present invention relates to a coating composition containing activated carbon having a central particle size of 1000 nm or less, and a method for producing the same.

Activated carbon is known to have an adsorption function for odors and pollutants, and activated carbon is widely used in equipment and tools for purifying air and water, deodorants, and the like. In many such applications, activated carbon is used in the form of granules, powders, activated carbon molded filters, plastic products containing activated carbon, and the like. In recent years, there has been an increasing demand for higher performance and diversification of cleaning equipment for various odorous components, and various formulations that can be applied directly on the base material such as spray formulations and paint molds have been proposed for the usage patterns of activated carbon. Has been done. For example, Patent Document 1 discloses a deodorant for spraying, which contains activated carbon as a functional substance together with cellulose nanofibers and can be easily peeled off even after drying by shrinking with time. Further, Patent Document 2 discloses an adsorptive paint formulation comprising a mixture of a submicron activated carbon having a median particle size of less than 1 μm and an aqueous binder system for dispersing the activated carbon. ..

JP-A-2018-196550 Japanese Patent Application Laid-Open No. 2008-530311

However, in general, the average particle size of powdered activated carbon is about 10 μm even if it is crushed relatively finely, and the activated carbon used in the activated carbon-containing spraying agent as described in Patent Document 1 is described. Even if it is miniaturized, it often has an average particle size of several μm (for example, about 5 μm). Normally, the paint is often applied with a thickness of about 10 to 100 μm, but it is thinner (for example, from 1 μm) for the purpose of adding the adsorption performance of activated carbon to fine and complicated precision parts, fibers, paper, etc. It is necessary to form a uniform coating film (20 μm, etc.), and with activated carbon finely divided to about 5 μm, spots may occur or the thickness may vary due to the activated carbon. On the other hand, when the activated carbon is further refined and a submicron activated carbon having a central particle size of less than 1 μm is used in the coating composition, it is disclosed in Patent Document 2 in order to prevent the fine activated carbon from falling off from the coated surface. It was necessary to add a large amount of binder and the like. However, when a large amount of a binder or the like is blended, pore clogging of the activated carbon is likely to occur, and it is difficult to maintain sufficient adsorption performance particularly when the content of the activated carbon is small.

According to the present invention, even if the content of activated carbon is small, a coating film that is thin, uniform, and has an excellent appearance with respect to a coating film forming object (base material) can be easily obtained while ensuring sufficient adsorption performance by the activated carbon. It is an object of the present invention to provide a composition for a coating film which can be formed.

The present inventors have arrived at the present invention as a result of repeated detailed studies on carbonaceous materials and methods for producing the same in order to solve the above problems.
That is, the present invention includes the following aspects.
[1] A coating composition containing activated carbon and a liquid dispersion medium.
A coating composition in which the activated carbon is an activated carbon having a central particle size D ₅₀ of 1000 nm or less, and the content of the activated carbon is 1% by mass or more and 10% by mass or less with respect to the total mass of the coating composition.
[2] The coating composition according to the above [1], further comprising cellulose nanofibers, wherein the mass ratio of cellulose nanofibers to activated carbon (cellulose nanofibers / activated carbon) is less than 0.4.
[3] The coating composition according to the above [2], wherein the content of the cellulose nanofibers is 0.5% by mass or less with respect to the total mass of the coating composition.
[4] The viscosity η (a) measured at 20 ° C. at a shear rate of ^{5 × 10 -3} s ^-1 using a B-type viscometer ^{is 8 × 10 2} mPa · s or more 1.2 × 10 ⁴ mPa. -The coating composition according to any one of the above [1] to [3], which is s or less.
[5] The above-mentioned [1] to [4], wherein the viscosity η (b) measured at 20 ° C. at a shear rate of ^{1s -1} using a B-type viscometer ^{is 3 × 10 2 mPa · s or less.} The coating composition according to any one.
[6] The coating composition according to any one of [1] to [5] above, further comprising an additive.
[7] Additives are insect repellents, insecticides, antibacterial agents, dispersants, humidity control agents, photocatalytic materials, pigments, adsorbents other than activated charcoal, adsorbents, resins, wetting agents, thickeners other than cellulose nanofibers. , Anti-settling agent, surface regulator, anti-skin agent, anti-dripping agent, leveling agent, anti-repellent agent, anti-armpit agent, curing catalyst, plastic agent, matting agent, anti-scratch agent, ultraviolet absorber, light stabilizer The above [6] includes at least one selected from the group consisting of preservatives, adsorbents, antistatic agents, flame retardants, antifouling agents, antioxidants, pH regulators, antifoaming agents and emulsifiers. The composition for paints described.
[8] The coating composition according to the above [6] or [7], wherein the content of the additive is 30% by mass or less with respect to the total mass of the coating composition.
[9] The coating material according to any one of [1] to [8] above, wherein the solid content concentration in the coating composition is 1% by mass or more and 20% by mass or less with respect to the total mass of the coating composition. Composition.
[10] A step (1) of obtaining a mixture by mixing a raw material activated charcoal having a central particle size D ₅₀ of 3 to 30 μm and a liquid dispersion medium so that the concentration of the raw material activated charcoal in the mixture is 1 to 30% by mass. The mixture obtained in the above step (1) is wet-ground with a bead mill using zirconia beads having a particle size of 0.2 to 1 mm, and is liquid with activated charcoal having _{a central particle size D 50 of 1000 nm or less.} Step of obtaining a mixture with a dispersion medium (2)
The method for producing a coating composition according to any one of the above [1] to [9], which comprises.
[11] A spray preparation containing the coating composition according to any one of the above [1] to [9].

According to the present invention, even if the content of activated carbon is small, a coating film that is thin, uniform, and has an excellent appearance with respect to a coating film forming object (base material) can be obtained while ensuring sufficient adsorption performance by the activated carbon. It is possible to provide a coating composition that can be easily formed.

Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described here, and various modifications can be made without impairing the gist of the present invention.

The coating composition of the present invention contains activated carbon. The activated carbon contained in the coating composition of the present invention _{is an activated carbon having a central particle size D 50} of 1000 nm or less (hereinafter, also referred to as “submicron activated carbon”). When the central particle size of the activated carbon contained in the coating composition exceeds 1000 nm, spots due to the activated carbon occur and the thickness varies, making it difficult to form a uniform and thin coating film, and in particular, fine particles. It becomes difficult to obtain a coating film having an excellent appearance with respect to a coating film forming object having a various shape or a complicated shape. In the present invention, the central particle size D ₅₀ of the activated carbon is preferably 800 nm or less, more preferably 600 nm or less, still more preferably 500 nm or less. Further, from the viewpoint of ensuring the adsorption performance and the balance between good coatability, _{the lower limit of the central particle size D 50} of the activated carbon is preferably 10 nm or more, more preferably 50 nm or more, and further preferably 100 nm or more. ..

In the present invention, the central particle size D ₅₀ of activated carbon is an average particle size that can be measured by a laser diffraction measurement method or a dynamic light scattering method, and means the central particle size (D ₅₀ ) in the volumetric particle size distribution. Further, the average particle size in the present invention means the average particle size of the primary particles. General powdered activated carbon having a particle size distribution in the range of about 1 to 100 μm can be measured with high accuracy by a laser diffraction measurement method, and submicron activated carbon having a particle size distribution in the range of about 100 to 1000 nm can be measured with high accuracy. Measurement is possible with relatively high accuracy by the dynamic light scattering method. Therefore, in the present invention, as a general rule, _{powdered activated carbon having a central particle size D 50} exceeding 1 μm is measured by a laser diffraction measurement method, and _{submicrons having a central particle size D 50} of less than 1 μm are measured. For activated carbon, the value measured by the dynamic light scattering method is adopted. In the laser diffraction measurement method, for example, the Microtrack MT3000II series (manufactured by Nikkiso Co., Ltd.) capable of measuring a wide range of 0.02 to 2,800 μm with high resolution by adopting the three laser method can be used. Further, in the dynamic light scattering method, Nanotrack UPA series (manufactured by Nikkiso Co., Ltd.), which can measure in the range of 0.8 to 6,500 nm by the measurement by the heterodyne method, can be used. More specifically, the central particle size D ₅₀ of the activated carbon can be measured according to the method described in Examples described later.

In the present invention, the BET specific surface area of the submicron activated carbon is preferably 700 m ² / g or more, more preferably 800 m ² / g or more, still more preferably 900 m ² / g or more, and preferably 1700 m ² / g or less. , more preferably 1650 m ² / g, more preferably not more than 1600 m ² / g. When the BET specific surface area of the activated carbon is at least the above lower limit value, high adsorption performance can be expected even in the finely divided submicron activated carbon. Further, when the BET specific surface area is not more than the above upper limit, the bulk density of the submicron activated carbon increases, so that high adsorption performance can be expected per unit volume as a paint.
In the present invention, the BET specific surface area can be measured and calculated by the nitrogen adsorption method.

Submicron activated carbon can usually be obtained by carbonizing and activating a carbon precursor as a raw material, and has micropores with a pore diameter of less than 2 nm, mesopores with a pore diameter of 2 nm or more and 50 nm or less, and macros with a pore diameter of 50 nm or more. There is a hole.
In the present invention, the total pore volume of the activated carbon is preferably 0.2 cm ³ / g or more, more preferably 0.3 cm ³ / g or more, still more preferably 0.4 cm ³ / g or more, and preferably 0.4 cm 3 / g or more. It is 1.1 cm ³ / g or less, more preferably 1.0 cm ³ / g or less, still more preferably 0.8 cm ³ / g or less.

The content of submicron activated carbon in the coating composition of the present invention is 1% by mass or more and 10% by mass or less with respect to the total mass of the coating composition. If the content of the submicron activated carbon is less than 1% by mass, it becomes difficult to impart sufficient adsorption performance to the coating composition. Further, when the content of the submicron activated carbon exceeds 10% by mass, the viscosity becomes too high due to the submicron activated carbon and the coatability deteriorates. Therefore, a coating composition for forming a thin and uniform coating film. It becomes difficult to control the viscosity suitable for. In the present invention, the content of the submicron activated carbon is preferably 1.5% by mass or more, more preferably 2% by mass or more, and preferably 8% by mass or less, based on the total mass of the coating composition. , More preferably 7% by mass or less, further preferably 6% by mass or less, particularly preferably 5% by mass or less, and particularly preferably less than 5% by mass. In particular, when the composition for paint is used as a spray formulation, it is easy to obtain the effect of suppressing dripping while preventing liquid clogging at the time of spray spraying, and it is a thin film that suppresses the occurrence of spray spots and is excellent in appearance. Since a uniform coating film can be formed, the content of the submicron activated carbon is preferably within the above range.

In the present invention, the carbon precursor used as a raw material for the submicron activated carbon is not particularly limited as long as it forms activated carbon by activation, and is derived from a plant-derived carbon precursor, a mineral-derived carbon precursor, or a natural material. Can be appropriately selected from the carbon precursors of the above and carbon precursors derived from synthetic materials, depending on the use of the coating composition and the like. Specifically, for example, as plant-derived carbon precursors, fruit shells such as wood, sawdust, charcoal, coconut shells, and walnut shells, fruit seeds, pulp-producing by-products, lignin, waste sugar honey, and other mineral-derived carbon precursors. As a body, pulp, grass charcoal, subchar, brown charcoal, leki blue charcoal, smokeless charcoal, coke, coal tar, coal pitch, petroleum distillation residue, petroleum pitch, etc. Examples of the carbon precursor derived from the material include phenol, saran, and acrylic resin.
Of these, plant-derived carbon precursors (particularly coconut shells), bituminous coal, and the like are preferable because activated carbon that is easily available, has excellent processability, and has high adsorption performance can be produced.

The submicron activated carbon is finely divided by, for example, a pulverization method such as that used in the method for producing a coating composition of the present invention described later, in which activated carbon obtained by activating a carbide obtained by carbonizing a carbon precursor as described above is activated. It can be manufactured by carbonizing. Hereinafter, in the present specification, the activated carbon before the pulverization treatment obtained by carbonizing and activating the carbon precursor may be referred to as "raw material activated carbon". The method for carbonizing and activating the carbon precursor is not particularly limited, and a conventionally known method may be adopted as a method for obtaining the raw material activated carbon.
Further, commercially available raw material activated carbon may be used as the raw material activated carbon. Examples of such commercially available products include Kuraray Call PGW, Kuraray Call PW, and Kuraray Call PKC [all manufactured by Kuraray Co., Ltd.].

The coating composition of the present invention contains a liquid dispersion medium. In the present invention, the liquid dispersion medium means a solvent capable of dispersing the raw material activated carbon and the submicron activated carbon, which are liquid at room temperature (25 ° C.). The liquid dispersion medium is not particularly limited as long as it can disperse the raw material activated carbon or the submicron activated carbon and can pulverize the raw material activated carbon to a desired size, and is not particularly limited. It may be selected as appropriate. Specifically, for example, alcohol solvents such as water, methanol, ethanol, isopropanol and butanol, ether solvents such as diethyl ether and ethylene glycol monoethyl ether, ketone solvents such as acetone, aliphatic hydrocarbon solvents such as hexane, and cyclohexane. Examples thereof include alicyclic hydrocarbon solvents such as, and aromatic hydrocarbon solvents such as toluene and m-xylene.

As the liquid dispersion medium constituting the coating composition of the present invention, a volatile solvent that can be vaporized when a coating film is formed from the coating composition is preferable. In the present specification, the volatile solvent means a solvent that gradually vaporizes under normal temperature and pressure (25 ° C., about 1 atm), and specifically, the vapor pressure at 25 ° C. is 1 × 10 ^-7 Pa or more. It is a solvent. As such a volatile solvent (liquid dispersion medium), water, an alcohol solvent, and the like can be easily applied to coating compositions for various purposes, and can easily form a coating film having an excellent appearance. Alternatively, at least one selected from the group consisting of a mixture of water and an alcohol solvent is preferable, and ethanol is preferable as the alcohol solvent. As the liquid dispersion medium, one type may be used alone, or two or more types may be used in combination. In addition, the liquid dispersion medium used when crushing the raw material activated charcoal and the liquid dispersion medium (solvent) used to disperse the submicron activated charcoal in the coating composition and dissolve / disperse the additives to be blended as needed. ) May be the same or different.

The content of the liquid dispersion medium in the coating composition of the present invention may be appropriately determined according to the use of the coating composition, the desired viscosity, and the like. In one aspect of the present invention, it is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more, based on the total mass of the coating composition. Also, it is preferably 99% by mass or less, more preferably 98.5% by mass or less, still more preferably 98% by mass or less, and particularly preferably 97.5% by mass or less.

The coating composition of the present invention preferably contains cellulose nanofibers. By including the cellulose nanofibers, the fine structure of the fibrillated fibers of the cellulose nanofibers firmly entangles and holds the fine particles of the submicron activated carbon, so that the coating film formed from the coating composition is contacted or rubbed. The effect of suppressing the shedding of submicron activated carbon and the transfer to other articles is improved. Further, in the coating composition of the present invention, since the submicron activated charcoal that functions to impart adsorption performance can also function as a viscosity modifier, the coating material does not contain cellulose nanofibers having a thickening function. Although it is possible to impart an appropriate viscosity to the composition for use, cellulose nanofibers are compared with resins (binding agents) such as latex and water-soluble polymers, and general polymer-based thickeners or thickening polysaccharides. As a result, it is unlikely to cause pore clogging of the submicron activated carbon when blended in the coating composition, and therefore, it is suitable as a viscosity modifier for controlling the viscosity of the coating composition. In the coating composition of the present invention, the viscosity can be easily adjusted by using a relatively small amount of cellulose nanofibers without significantly affecting the adsorption performance of the submicron activated carbon.

In the present invention, the average fiber diameter of the cellulose nanofibers is preferably 500 nm or less, more preferably 300 nm or less, still more preferably 100 nm or less. When the average fiber diameter of the cellulose nanofibers is not more than the above upper limit, the cellulose nanofibers are less likely to settle in the coating composition, and good dispersibility can be easily ensured. The lower limit of the average fiber diameter of the cellulose nanofibers is not particularly limited, but from the viewpoint of reducing the catching power of the submicron activated carbon, it is usually 1 nm or more, preferably 5 nm or more, more preferably 10 nm or more. is there.

The average fiber diameter of cellulose nanofibers can be measured, for example, by an atomic force microscope (AFM, particularly suitable for measurement with a diameter of 20 nm or less) or a field emission scanning electron microscope (FE-SEM, especially when the diameter is 20 nm or more). It can be measured using (suitable), and can be obtained by analyzing 200 randomly selected fibers and calculating the average.

Cellulose nanofibers can be produced by a known production method. As a method for producing cellulose nanofibers, for example, as described in Japanese Patent Application Laid-Open No. 2010-37200, an oxidation reaction is carried out by adding a copolymer such as hypohalous acid to a dispersion liquid in which cellulose is dispersed. After that, a method for purifying and refining the cellulose; as described in JP-A-2019-127490 and JP-A-2019-997758, in carboxymethylation of cellulose, mercellization under a solvent mainly containing water. (Alkaline treatment of cellulose) and then carboxylation (also referred to as etherification) in a mixed solvent of water and an organic solvent; Examples thereof include a method in which a TEMPO catalyst is allowed to act to mechanically defibrate, and cellulose nanofibers produced according to such a method can be used in the coating composition of the present invention.

Alternatively, commercially available cellulose nanofibers may be used as the cellulose nanofibers. Examples of such commercially available products include Leocrysta (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and Serenpia (manufactured by Nippon Paper Industries, Ltd.).

When the coating composition of the present invention contains cellulose nanofibers, in the coating composition of the present invention, the mass ratio of cellulose nanofibers to submicron activated carbon (cellulose nanofibers / submicron activated carbon) exceeds 0, which is preferable. Is less than 0.4, more preferably 0.3 or less, still more preferably 0.17 or less, and particularly preferably 0.12 or less. The viscosity of the solution in which activated carbon is dispersed varies depending on the particle size and concentration of the _{activated carbon, but when submicron activated carbon having a central particle size D 50} of 1000 nm or less is used, general powdered activated carbon (center particle size D 50 is several μm). The viscosity of the dispersion solution tends to be higher than that in the case of dispersing (with a thickness of several tens of μm) at the same concentration. Therefore, when cellulose nanofibers are added to a coating composition containing submicron activated carbon, it is preferable to control the increase in solution viscosity due to submicron activated carbon and the increase in viscosity due to cellulose nanofibers in a well-balanced manner. When the mass ratio of the cellulose nanofibers to the submicron activated carbon is not more than the above upper limit, it is easy to control the viscosity of the coating composition while ensuring sufficiently high adsorption performance by the submicron activated carbon, and it is uniform, thin and visually appealing. It becomes easy to easily form an excellent coating film.

When the coating composition of the present invention contains cellulose nanofibers, the content thereof is preferably 0.5% by mass or less, more preferably 0.4% by mass or less, based on the total mass of the coating composition. It is more preferably 0.35% by mass or less, particularly preferably 0.3% by mass or less, and preferably 0.01% by mass or more, more preferably 0.03% by mass or more, still more preferably 0.05% by mass. % Or more. When the content of the cellulose nanofibers is within the above range, the adhesion of the submicron activated carbon to the coating film-forming surface of the base material or the like can be enhanced in the coating film formed from the coating composition, which causes rubbing or the like. It is possible to effectively suppress the resulting shedding of the submicron activated carbon, and it is easy to impart an appropriate viscosity to the coating composition while maintaining the adsorption performance of the submicron activated carbon. In particular, when the composition for paint is used as a spray formulation, it is easy to obtain the effect of suppressing dripping while preventing liquid clogging at the time of spray spraying, and it is a thin film that suppresses the occurrence of spray spots and is excellent in appearance. A uniform coating film can be formed.

In one aspect of the present invention, the content of cellulose nanofibers may be 0% by mass. In the coating composition of the present invention, since the submicron activated carbon that functions to impart adsorption performance can also function as a viscosity modifier, the coating composition does not include cellulose nanofibers having a thickening function. It is easy to control the viscosity of an object within an appropriate range. Such a coating composition can form a thin, uniform, and visually excellent coating film with respect to a coating film-forming object (base material) while ensuring sufficient adsorption performance by activated carbon. On the other hand, when contact or rubbing occurs on the formed coating film, a small amount of submicron activated carbon tends to fall off or transfer to other articles, etc., as compared with the formulation containing cellulose nanofibers. There is. In order to prevent this, for example, a solution containing cellulose nanofibers may be applied over a coating film formed from the coating composition of the present invention. Examples of the solution containing cellulose nanofibers include an aqueous solution of cellulose nanofibers. The coating method is not particularly limited, and various coating methods such as brush coating, roller coating, and spraying can be used.
It should be noted that such a solution containing cellulose nanofibers may be applied in layers even when the coating composition of the present invention contains cellulose nanofibers.

The coating composition of the present invention may contain an additive that can function to impart a desired function to the coating composition or adjust the physical properties of the coating composition. The additive can be appropriately selected depending on the intended use of the coating composition, etc., but in one aspect of the present invention, the coating composition of the present invention can be used as an additive such as an insect repellent, an insecticide, or an antibacterial agent. , Dispersants, humidity control agents, photocatalyst materials, pigments, adsorbents other than activated charcoal, excipients, resins (binding agents), wetting agents, thickeners (other than cellulose nanofibers), sedimentation inhibitors, surface conditioners, Anti-skin agent, anti-slip agent, leveling agent, anti-repellent agent, anti-armpit agent, curing catalyst, plasticizer, matte agent, anti-scratch agent, UV absorber, light stabilizer, preservative, algae nourishing agent, charging It contains at least one selected from the group consisting of antioxidants, flame retardants, antifouling agents, antioxidants, pH regulators, antifoaming agents and emulsifiers. These additives may be used alone or in combination of two or more.

Examples of the insect repellent and insecticide include pyrethroid insect repellent / insecticide components such as empentrin, transfluthrin, allethrin, phenothrin, eminence, and profluthrin, paradichlorobenzene, naphthalin, camphor, and 2-phenoxyethanol. These may be used alone or in combination of two or more.

As the antibacterial agent, an organic compound-based or inorganic compound-based antibacterial agent can be used. Specifically, as the organic compound-based antibacterial agent, a phenol-based compound, a pyridine-based compound, a thiazolin-based compound, and an imidazole-based compound are preferable. As the inorganic compound-based antibacterial agent, silver and silver chloride, silver compounds such as silver carbonate, copper and copper compounds, zinc and zinc compounds and the like are preferable. These may be used alone or in combination of two or more.

By using a dispersant, the effect of preventing the aggregation of activated carbon particles can be expected. Examples of the dispersant include a surfactant as a low molecular weight dispersant. As the surfactant, a nonionic surfactant, a cationic surfactant, an anionic surfactant, and an amphoteric surfactant are preferable, and more specifically, for example, ammonium polycarboxylate and polyacrylic acid. Sodium, sodium polymethacrylate, sodium diisobutylene / maleic anhydride, condensed sodium sodium phthalene sulfonate, sodium polystyrene sulfonate, sodium polystyrene / acrylate, alkylbenzene sulfonate, monoalkyl phosphate, alkylpolyoxyethylene sulfate Salts, monoalkylsulfates, sucroses, alkyldimethylamine oxides, alkylcarboxybetaines, carboxymethyl celluloses, polyvinyl alcohols and the like can be used. Examples of the polymer dispersant include homopolymers, random polymers, and block polymers. More specifically, for example, SMA resin, polyacrylic acid and the like can be used. Among them, a basic surfactant is preferable from the viewpoint of the effect of preventing aggregation of the activated carbon particles, and a dispersant having an aromatic amino group or a quaternary ammonium group or a salt thereof as an anchor portion is more preferable. These may be used alone or in combination of two or more.

Commercially available dispersants may be used, and commercially available surfactants include, for example, Demor NL, Emargen A-60, Emargen B-66, Sanizol (all manufactured by Kao Corporation). Eslim AD-3172M (manufactured by Nichiyu Co., Ltd.), Adeka Purlonic L-64 (manufactured by Adeka Corporation), and the like can be mentioned.

As the humidity control agent, for example, silica gel, calcium carbonate, calcium chloride and the like can be preferably used.

Examples of pigments include organic coloring pigments such as Hansaello, perylene red, and phthalocyanine blue, inorganic coloring pigments such as titanium oxide, zinc oxide, and carbon black, silica, kaolin, talc, calcium carbonate, precipitated barium sulfate, clay, and the like. In addition to extender pigments, fluorescent pigments, temperature indicating pigments, conductive pigments, heat insulating / heat insulating pigments, photocatalyst pigments, rust preventive pigments and the like can be mentioned.

As the adsorbent other than activated carbon, for example, zeolite, titanosilicate, silica gel, hydrotalcite, chitosan and the like can be used.

The submicron activated carbon can be used as the submicron activated carbon by blending the coating agent used for general impregnated charcoal as the adhering agent. Specifically, for basic gases such as ammonia, acidic compounds such as phosphoric acid, citric acid, and malic acid, for gases such as SOx, salts such as potassium carbonate, potassium hydroxide, calcium carbonate, and calcium hydroxide, and for aldehyde gas. Amino compounds such as ethylene urea, p-aminobenzoic acid and sulfanilic acid, precious metals such as palladium for ethylene gas, copper sulfate such as copper sulfate and manganese sulfate, and manganese compounds can be used for malodorous substances such as mercaptan.

When the object to which the coating composition is applied is plastic, metal, glass, etc. with less unevenness on the surface of the object to be coated, the coating film forming surface is formed by blending the resin (binding agent) with the coating composition. The adhesion of the submicron activated carbon to the resin tends to increase. Examples of such resins include rosin, nitrocellulose, vinyl chloride, rubber chloride, polystyrene, vinyl acetate emulsion, acrylic, (meth) acrylic acid ester, polyacrylic nitrile, and polymethacrylic acid used in general paints. Methyl, acrylic acid alkyl ester, methacrylic acid alkyl ester, acrylic emulsion, alkyd, unsaturated polyester, oil-free polyester, melanin, polyester / melanin, polyester / polyisocyanate, acrylic / melanin, polyisocyanate, polyurethane, acrylic / polyisocyanate, Examples thereof include phenol, epoxy, epoxy / polyamine, fluororesin for paint, fluorine / vinyl, silicon resin, silicon-modified acrylic, epoxy polyol resin, and other synthetic resin latex. However, when a large amount of these resins (binding agents) is blended, pore clogging of the submicron activated carbon is likely to occur, and the desired adsorption performance may not be obtained. Therefore, when these resins (binding agents) are contained, the content thereof is the total amount based on the total mass of the coating composition, preferably less than 5% by mass, more preferably 4% or less, still more preferably 3. % Or less, particularly preferably 2.5% or less.

The coating composition of the present invention may contain a thickener (viscosity adjusting substance) other than cellulose nanofibers. Typical examples of the thickener include thickening polysaccharides such as methyl cellulose, carboxymethyl cellulose, pectin, caranagin, xanthan gum and galactomannans, and general polymer thickeners such as acrylic polymer and carboxyvinyl polymer. Be done. When the coating composition of the present invention contains a thickener other than cellulose nanofibers (hereinafter, also referred to as "other viscosity adjusting substance"), the content thereof is the total amount with respect to the total mass of the coating composition. It is preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 3% by mass or less, and particularly preferably 1% by mass or less. When the content of the thickener other than the cellulose nanofibers is not more than the above upper limit, it is suitable for the composition for coating materials while suppressing the deterioration of the adsorption performance of the submicron activated carbon due to the blockage of the pores of the submicron activated carbon. Viscosity can be imparted.

The content of the additive in the coating composition of the present invention may be appropriately determined according to the type of the additive used, the desired function, the physical properties, and the like. When the coating composition of the present invention contains an additive, the content thereof is, preferably 30% by mass or less, more preferably 20% by mass or less, and further preferably 20% by mass or less, based on the total mass of the coating composition. It is preferably 10% by mass or less. When the content of the additive is not more than the above upper limit, the desired function of the additive can be easily exhibited without affecting the effect of the present invention and the physical properties of the coating composition. The lower limit of the content of the additive in the coating composition of the present invention is not particularly limited, and may be 0% by mass with respect to the total mass of the coating composition.

The solid content concentration in the coating composition of the present invention is preferably 1% by mass or more and 20% by mass or less with respect to the total mass of the coating composition. When the solid content concentration in the coating composition is within the above range, it is easy to secure good adsorption performance in the coating composition, and the coating composition is imparted with a viscosity suitable for forming a thin and uniform coating film. It will be easier to do. From the viewpoint of improving the adsorption performance, the solid content concentration is more preferably 1.5% by mass or more, further preferably 2% by mass or more, and a better balance between ensuring the adsorption performance and good coatability. From the above viewpoint, it is more preferably 18% by mass or less, further preferably 15% by mass or less, and particularly preferably 12% by mass or less.

The solid content concentration in the coating composition means the total amount of the components excluding volatile substances such as a liquid dispersion medium (solvent) from the coating composition. For the solid content concentration in the coating composition, for example, the total amount of the components excluding volatile substances such as the liquid dispersion medium (solvent) at the time of preparing the coating composition is the total amount of the coating composition. It can be calculated by dividing by and multiplying by 100. Alternatively, 100 g of the paint composition to be measured using an electronic balance is weighed in a glass beaker, dried in a dryer adjusted to 120 ° C. for 16 hours, and immediately measured with an electronic balance to measure the weight value Xg. Measure and formula:
Solid content concentration (%) = weight after drying X (g) / 100 (g) x 100
It can be calculated according to.

The viscosity of the coating composition of the present invention determines the use of the coating composition, the shape and material of the object to which the coating composition is applied, the degree of unevenness on the surface of the object to be coated, and the required amount of coating according to the purpose. It may be decided as appropriate according to the above. In the coating composition of the present invention, since the sub-micron activated carbon which acts to impart adsorption performance it can also serve as a viscosity modifier, the content of the central particle diameter D ₅₀ and the sub-micron activated carbon submicron activated carbon By adjusting the above, the composition for coating can be easily controlled to a desired viscosity range with a small amount of viscosity adjusting substance such as cellulose nanofibers or without using a viscosity adjusting substance. As a result, various shapes and shapes can be obtained by using various coating methods such as brush coating, roller coating, trowel coating, curtain flow, roll coater, immersion coating, airless spray, electrostatic spray, electrodeposition coating, and inkjet method. It can be a coating composition capable of easily forming a coating film which is thin and uniform with respect to a coating film forming object (base material) made of a material and has an excellent appearance.

In one aspect of the present invention, the coating composition of the present invention has a viscosity η (a) of 8 × 10 measured at 20 ° C. at a shear rate of ^{5 × 10 -3} s ^{-1 using a B-type viscometer. It is preferably 2} mPa · s or more and 1.2 × 10 ⁴ mPa · s or less. When the viscosity η (a) is in the above range, it becomes easy to suppress dripping when applied to the coating film-forming object while ensuring good coatability of the coating composition, and the shape is fine or complicated. It is possible to obtain a thin film coating film having an excellent appearance even in the object. In the present invention, the viscosity η (a) of the coating composition is more preferably 1.5 × 10 ³ mPa · s or more, further preferably 3 × 10 ³ mPa · s or more, and more preferably 1 It is 0.0 × 10 ⁴ mPa · s or less, more preferably 8 × 10 ³ mPa · s or less.

Further, in another aspect of the present invention, the coating composition of the present invention has a viscosity η (b) of 3 × 10 ^{2 measured at 20 ° C. at a shear rate of 1s -1 using a B-type viscometer.} It is preferably mPa · s or less. When the viscosity η (b) is not more than the above upper limit, it is suitable as a composition to be discharged from a relatively small discharge port, and good sprayability / discharge property can be realized when discharged by a spray method or an inkjet method. In the present invention, the viscosity η (b) of the coating composition is more preferably 2 × 10 ² mPa · s or less, still more preferably 1 × 10 ² mPa · s or less. The lower limit of the viscosity η (b) of the coating composition is not particularly limited, but is, for example, 1 mPa · s or more.

The coating composition of the present invention is, for example,
A step (1) of mixing a raw material activated charcoal having a central particle diameter D ₅₀ of 3 to 30 μm and a liquid dispersion medium so that the concentration of the raw material activated charcoal in the mixture is 1 to 30% by mass to obtain a mixture, and the above-mentioned step. The mixture obtained in (1) is wet-ground with a bead mill using zirconia beads having a particle size of 0.2 to 1 mm, _{and the activated charcoal having a central particle size D 50} of 1000 nm or less and a liquid dispersion medium are used. Step of obtaining a mixture of (2)
It can be manufactured by a manufacturing method including.

Steps (1) and (2) are steps for obtaining the submicron activated carbon constituting the coating composition of the present invention from the raw material activated carbon.
In step (1), the raw material activated carbon having a particle size larger than the particle size of the finally desired submicron activated carbon is mixed with a liquid dispersion medium for dispersing the raw material activated carbon, and the raw material activated carbon and the liquid dispersion medium are mixed. It is a step of obtaining a mixture with.

_{The core particle size D 50} of the raw material activated carbon suitable for obtaining the submicron activated carbon constituting the coating composition of the present invention is preferably 3 to 30 μm, more preferably 5 to 15 μm. By using the activated carbon having the central particle size D ₅₀ as a raw material, it is possible to efficiently obtain the submicron activated carbon as compared with the case where the activated carbon having a large particle size of 30 μm or more is used as a raw material. In addition, it is possible to prevent the residue of particles having a size of 1 μm or more in the obtained submicron activated carbon, although the amount is small. _{The central particle size D 50} of the raw material activated carbon can be measured and calculated by a laser diffraction measurement method.

In the step (1), the raw material activated carbon and the liquid dispersion medium are mixed so that the concentration of the raw material activated carbon in the obtained mixture is preferably 1 to 30% by mass, more preferably 10 to 25% by mass. When the concentration of the raw material activated carbon in the mixture is within the above range, the efficiency is high under the condition that the submicron activated carbon is pulverized by a bead mill or the like. Further, in the case of further mixing with other additives, adjusting the content of the submicron activated carbon to 1% by mass or more and 10% by mass or less with respect to the total mass of the coating composition for use as a coating material. Is also easy.

A surfactant may be added as a dispersant to the mixture of the raw material activated carbon and the liquid dispersion medium, if necessary. By using an appropriate amount of the surfactant as the dispersant, the dispersed state of the coating composition can be improved, and the precipitation of components such as submicron activated carbon in the composition can be effectively suppressed. The amount of the surfactant in that case is preferably 0.1 to 2.0% by mass, more preferably 0.2 to 0.5% by mass, based on the total mass of the obtained mixture.

The mixing conditions of the raw material activated carbon and the liquid dispersion medium are not particularly limited, and a uniform mixture can be obtained depending on the particle size and concentration of the raw material activated carbon, the type of the liquid dispersion medium, the equipment and facilities used for mixing, and the like. It may be decided as appropriate. For example, a dissolver, a butterfly mixer, or the like may be used as the stirrer.

Step (2) is a step of pulverizing the raw material activated carbon into submicron activated _{carbon having a central particle size of D 50 1000 nm or less by wet pulverization.}
The raw material activated carbon can be pulverized using a known fine pulverizer such as a roll mill, a jet mill, a ball mill, or a bead mill. Above all, it is preferable to use a bead mill from the viewpoint that it is easy to efficiently obtain submicron activated carbon in a short time. These devices may be used in combination as needed, or may be classified by a sieve or a wind classifier.

When a ball mill or a bead mill is used as the crusher, the material of the medium (ball or bead) is not particularly limited, and for example, glass, alumina, zircon, silica, ceramics, titania, zirconia, steel and the like can be used. .. The media is preferably zirconia beads from the viewpoint of preventing contamination from the media and easily shortening the crushing time. When zirconia beads are used, the particle size of the beads is preferably 0.2 to 1 mm, more preferably 0.2 to 0.5 mm, from the viewpoint of more efficiently refining to submicron activated carbon. preferable. The filling rate of the media in the crusher is not particularly limited, but is preferably 50 to 95%, more preferably 70 to 90%, from the viewpoint of easily suppressing deformation during crushing. The crushing time may be appropriately determined according to the particle size of the raw material activated carbon, the type of crusher used, and the like so that the crushing time can be crushed to a desired particle size. For example, by reducing the bead diameter or lengthening the crushing time, it becomes easier to obtain a smaller particle size.

By adopting wet pulverization in which the raw material activated carbon is dispersed in a liquid dispersion medium, submicron activated carbon having a central particle size of 1000 nm or less, which is difficult to obtain by dry pulverization, can be efficiently obtained. ..
After wet pulverization, the obtained mixture containing the submicron activated carbon and the liquid dispersion medium may be subjected to a concentration treatment for adjusting the concentration. As a method of concentration treatment, for example, a filter press, a rotary filter, a drum type dryer, a cylinder type dryer, a shelf type hot air dryer, a conduction heating type dryer, or the like is used to disperse the liquid to a desired concentration. Examples include methods for reducing or removing the medium.

In the present invention, the mixture of the submicron activated charcoal and the liquid dispersion medium obtained through the above steps (1) and (2) or a concentrate thereof may be used as it is as a coating composition, and the mixture or concentrate may be used as it is. May be mixed and dispersed in a further liquid dispersion medium (solvent) together with other components such as additives, if necessary, as a coating composition. In the latter case, the liquid dispersion medium for dispersing the mixture of the submicron activated carbon and the liquid dispersion medium may be the same as or different from the liquid dispersion medium used for dispersing the raw material activated carbon during wet pulverization. ..

In addition to bead mills, roll mills, ball mills, homogenizers, high shear mixers, generator-type dispersers, emulsification dispersers, and ultrasonic dispersions are used to mix and disperse a mixture of submicron activated charcoal and a liquid dispersion medium in a further liquid dispersion medium. A known disperser such as a machine can be used. Further, as the stirrer, a dissolver, a butterfly mixer or the like may be used. The conditions for mixing and dispersing are not particularly limited, and may be appropriately determined depending on the composition of the coating composition, the equipment used, and the like.

The coating composition of the present invention is prepared by mixing and dispersing submicron activated carbon, a liquid dispersion medium, and cellulose nanofibers and additives as required, and can have good thixotropy. As a result, when used as a spray preparation or inkjet ink ejected as droplets, the viscosity can be reduced during spray spraying or droplet ejection to achieve good spraying / ejection, but after spraying / ejection, Since the viscosity is restored to the extent that the droplets are fixed on the coated surface, dripping after sticking to the coated surface is unlikely to occur.
Therefore, the present invention also covers a spray preparation containing the composition for a paint of the present invention.

For example, the spray preparation of the present invention can be obtained by accommodating the coating composition of the present invention in a spraying device. The spraying device can be filled with the composition for paint of the present invention, and is not particularly limited as long as it can be sprayed, and may be appropriately selected depending on the intended use and the like. For example, pump sprayer, trigger sprayer, aerosol sprayer, accumulator sprayer, hand-push sprayer, electric sprayer, power storage sprayer, engine sprayer, gravity air spray gun, suction air spray gun, electric air Examples include a spray gun, an air brush with a compressor, and a rechargeable air brush.

The coating composition of the present invention is suitable for forming a thin and uniform coating film. Although it depends on the coating method, for example, when the coating composition of the present invention is applied as a spray formulation, for example, 25 to 100 μm, preferably 20 to 50 μm, more preferably, while ensuring sufficient adsorption performance by the submicron activated carbon. It can be applied with a thickness of 15 to 25 μm.

The coating composition of the present invention can be used as, for example, a deodorant, a fragrance, an insect repellent, an insecticide, an antibacterial agent, etc., and can be used as a VOC for apartments, detached houses, educational facilities, commercial facilities, hospitals, etc. Volatile organic compounds) Countermeasures against odors and odors are required on the inner walls of buildings and under the floor, the inner walls of clog boxes, the inner walls of refrigerators and deodorant containers for refrigerators, kitchen utensils, toilet supplies and walls, the inner surface of trash cans and the back of lids, etc. General household products, medical equipment, medical products, nursing care products, beds, storage cases, various packaging materials, etc. can be applied as objects. Further, in precision instruments such as facsimiles and hard disks, and electronic devices, the coating composition of the present invention is applied to the inner wall of these devices and the inner wall of the case in order to protect against gas generated from the inside and gas invading from the outside. By doing so, it is not necessary to secure a space for accommodating the sintered body or molded body of activated carbon, which has been conventionally required, and it is possible to contribute to further miniaturization and thinning of precision equipment and electronic equipment. Further, the composition for coating of the present invention can be used as it is for molded articles and processed products made of various materials such as urethane foam sheets, polyethylene foam sheets, polyethylene foam beads, various plastic beads, cloths, woven fabrics, non-woven fabrics, threads or fibers. It can be applied, and deodorant and adsorption performance can be imparted. Further, the coating composition of the present invention can be used as a colorant or the like as a substitute for carbon black, and can be used as a hair coloring agent or the like, for example.

The present invention will be described in more detail below based on the examples, but the following examples do not limit the present invention. Each physical property value in Examples and Comparative Examples was measured by the following method.

<Measurement of particle size>
_{-Measurement of the central particle size (D 50} ) of the raw material activated carbon and the activated carbons of Comparative Examples 1 and 2 The activated carbon to be measured was put into ion-exchanged water together with a surfactant, and ultrasonic vibration was applied to prepare a uniform dispersion liquid, and a laser was prepared. The measurement was performed using a particle size distribution measuring device (“Microtrac MT3300EX-II” manufactured by Microtrac Bell Co., Ltd.) by a diffraction measurement method. As the surfactant, "polyoxyethylene (10) octylphenyl ether" manufactured by Wako Pure Chemical Industries, Ltd. was used.
-Measurement of central particle size (D ₅₀ ) and cumulative 99% diameter (D ₉₉ ) of submicron activated charcoal The activated charcoal to be measured is placed in ion-exchanged water together with a surfactant and subjected to ultrasonic vibration to prepare a uniform dispersion. _{, The central particle size (D 50} ) and the cumulative 99% diameter (D ₉₉ ) were measured using a particle size distribution measuring device (“Nanotrack UPA150” manufactured by Microtrac Bell) by a dynamic light scattering method. As the surfactant, "polyoxyethylene (10) octylphenyl ether" manufactured by Wako Pure Chemical Industries, Ltd. was used.

<Measurement of BET specific surface area>
Using BELSORP-MAX manufactured by Microtrac Bell Co., Ltd., the activated carbon to be measured is heated at 300 ° C. for 5 hours under reduced pressure (vacuum degree: 0.1 kPa or less), and then nitrogen adsorption isotherm at 77 K. Was measured. The obtained nitrogen adsorption isotherm was analyzed by the multipoint method by the BET formula, and the BET specific surface area was calculated from the straight line in the region of the _{relative pressure P / P 0 = 0.01 to 0.1 of the obtained curve.} ..

1. 1. Preparation of paint composition Example 1
As the raw material activated carbon, coconut shell powder activated carbon (PGW-BF manufactured by Kuraray, center particle size D ₅₀ : 8 μm) was used and mixed with ion-exchanged water to prepare a mixture containing the raw material activated carbon at a concentration of 10% by mass. By wet pulverizing this mixture with a bead mill (NAM-1 type manufactured by IMEX, zirconia beads, bead diameter: 0.2 mm) for 16 hours, the center particle diameter (cumulative average diameter) D ₅₀ = 323 nm, cumulative 99% diameter D. A 10% by mass slurry of submicron activated carbon _{having 99} = 947 nm and a BET specific surface area = 1100 m ^{2 / g was obtained.} Ion-exchanged water (liquid dispersion medium in Table 1, rounded to the first decimal place in Table 1, the same applies hereinafter) is mixed with this slurry according to the formulation shown in Table 1, and a composition for coating of submicron activated carbon is mixed. Got

Examples 2-7
Cellulose nanofibers (Serenpia manufactured by Nippon Paper Industries, Ltd.) (CNF in Table 1, rounded off to the third decimal place in Table 1, are described in a 10% by mass slurry of submicron activated carbon obtained by the method of Example 1. The same) and ion-exchanged water were mixed according to the formulation shown in Table 1 to obtain a coating composition of submicron activated carbon.

Example 8
Cellulose nanofibers (Selenpia manufactured by Nippon Paper Co., Ltd.) and latex (LX812 manufactured by Nippon Zeon) as a resin (binding agent) (additives in Table 1) in a 10 mass% slurry of submicron activated carbon obtained by the method of Example 1. 1), Carboxymethyl cellulose (cellogen WSA manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) (additive 2 in Table 1) as a thickener, and ion-exchanged water are mixed according to the formulation shown in Table 1, and a composition for coating of submicron activated carbon is mixed. Got

Example 9
Cellulose nanofibers (Selenpia manufactured by Nippon Paper Co., Ltd.) and sodium salt of anionic surfactant β-naphthalene sulfonic acid formalin condensate as a dispersant were added to a 10% by mass slurry of submicron activated carbon obtained by the method of Example 1. Kao Demol NL) (additive 1 in Table 1) and ion-exchanged water were mixed according to the formulation shown in Table 1 to obtain a coating composition of submicron activated carbon.

Example 10
Cellulose nanofibers (Selenpia manufactured by Nippon Paper Co., Ltd.) and a nonionic surfactant polyoxyethylene distyrene phenyl ether (manufactured by Kao) as a dispersant are added to a 10 mass% slurry of submicron activated carbon obtained by the method of Example 1. Emulgen A-60) (additive 1 in Table 1) and ion-exchanged water were mixed according to the formulation shown in Table 1 to obtain a coating composition of submicron activated carbon.

Example 11
Cellulose nanofibers (Selenpia manufactured by Nippon Paper Co., Ltd.) and a cationic surfactant alkylbenzyldimethylammonium chloride (Sanisol manufactured by Kao) as a dispersant are added to a 10% by mass slurry of submicron activated carbon obtained by the method of Example 1 (Sanisol manufactured by Kao). Additives 1) in Table 1 and ion-exchanged water were mixed according to the formulation shown in Table 1 to obtain a coating composition of submicron activated carbon.

Example 12
Cellulose nanofibers (Selenpia manufactured by Nippon Paper Industries, Ltd.) and a polyalkylene glycol derivative (Esleam AD-3172M manufactured by Nippon Paper Industries) as a dispersant were added to a 10 mass% slurry of submicron activated carbon obtained by the method of Example 1 (Table 1). Additive 1) and ion-exchanged water were mixed according to the formulation shown in Table 1 to obtain a coating composition of submicron activated carbon.

Example 13
Cellulose nanofibers (Selenpia manufactured by Nippon Paper Co., Ltd.) and a nonionic surfactant polyoxyethylene-polyoxypropylene condensate (ADEKA) as a dispersant are added to a 10% by mass slurry of submicron activated carbon obtained by the method of Example 1. Adeka Purronic L-64) (additive 1 in Table 1) and ion-exchanged water were mixed according to the formulation shown in Table 1 to obtain a coating composition of submicron activated carbon.

Example 14
Cellulose nanofibers (Selenpia manufactured by Nippon Paper Co., Ltd.) and titanium oxide (ST-21 manufactured by Ishihara Sangyo Co., Ltd.) as a photocatalyst (additive 1 in Table 1) in a 10 mass% slurry of submicron activated carbon obtained by the method of Example 1. ), Ion-exchanged water was mixed according to the formulation shown in Table 1 to obtain a coating composition of submicron activated carbon.

Example 16
As the raw material activated carbon, coconut shell powder activated carbon (PGW-BF manufactured by Kuraray, center particle size D ₅₀ : 8 μm) was used and mixed with ion-exchanged water to prepare a mixture containing the raw material activated carbon at a concentration of 10% by mass. By wet pulverizing this mixture with a bead mill (NAM-1 type manufactured by IMEX, zirconia beads, bead diameter: 0.2 mm) for 30 minutes, the center particle diameter (cumulative average diameter) D ₅₀ = 900 nm, cumulative 99% diameter D. A 10% by mass slurry of submicron activated carbon _{having 99} = 4383 nm and a BET specific surface area = 1100 m ^{2 / g was obtained.} Cellulose nanofibers (Selenpia manufactured by Nippon Paper Industries, Ltd.) and ion-exchanged water were mixed with this slurry according to the formulation shown in Table 1 to obtain a coating composition of submicron activated carbon.

Example 17
As the raw material activated carbon, coconut shell powder activated carbon (PGW-BF manufactured by Kuraray, center particle size D ₅₀ : 8 μm) was used and mixed with ion-exchanged water to prepare a mixture containing the raw material activated carbon at a concentration of 10% by mass. By wet pulverizing this mixture with a bead mill (NAM-1 type manufactured by IMEX, zirconia beads, bead diameter: 0.2 mm) for 10 hours, the center particle diameter (cumulative average diameter) D ₅₀ = 500 nm, cumulative 99% diameter D. A 10% by mass slurry of submicron activated carbon _{having 99} = 1921 nm and a BET specific surface area = 1100 m ^{2 / g was obtained.} Cellulose nanofibers (Selenpia manufactured by Nippon Paper Industries, Ltd.) and ion-exchanged water were mixed with this slurry according to the formulation shown in Table 1 to obtain a coating composition of submicron activated carbon.

Comparative Example 1
PGW-BF manufactured by Kuraray (center particle size D ₅₀ : 8 μm), cellulose nanofibers (Selenpia manufactured by Nippon Paper Industries, Ltd.) and ion-exchanged water were mixed according to the formulation shown in Table 1 to obtain a coating composition of activated carbon. ..

Comparative Example 2
As the raw material activated carbon, coconut shell powder activated carbon (PGW-BF manufactured by Kuraray, center particle size D ₅₀ : 8 μm) was mixed with ion-exchanged water to prepare a 10% by mass aqueous solution. By wet pulverizing this aqueous solution with a bead mill (NAM-1 type manufactured by IMEX, zirconia beads, bead diameter: 1.0 mm), the center particle diameter D ₅₀ = 3.0 μm and the BET specific surface area = 1100 m ² / g. A 10% by mass slurry of activated carbon was obtained. Cellulose nanofibers (Selenpia manufactured by Nippon Paper Industries, Ltd.) and ion-exchanged water were mixed with this slurry according to the formulation shown in Table 1 to obtain a coating composition of activated carbon.

Comparative Example 3
As the raw material activated carbon, coconut shell powder activated carbon (PGW-BF manufactured by Kuraray, center particle size D ₅₀ : 8 μm) was mixed with ion-exchanged water to prepare a 10% by mass aqueous solution. By wet pulverizing this aqueous solution with a bead mill (NAM-1 type manufactured by IMEX, zirconia beads, bead diameter: 0.2 mm), the center particle diameter D ₅₀ = 323 nm, the cumulative 99% diameter D ₉₉ = 947 nm, BET ratio. A 10% by mass slurry of submicron activated carbon having a surface area of 1100 m ^{2 / g was obtained.} This slurry was concentrated to 17% by mass using a ceramic rotary filter CRF-0 (manufactured by Hiroshima Metal & Machinery). Cellulose nanofibers (Selenpia manufactured by Nippon Paper Industries, Ltd.) and ion-exchanged water were mixed with this concentrate according to the formulation shown in Table 1 to obtain a coating composition of submicron activated carbon.

Comparative Example 4
As the raw material activated carbon, coconut shell powder activated carbon (PGW-BF manufactured by Kuraray, center particle size D ₅₀ : 8 μm) was mixed with ion-exchanged water to prepare a 10% by mass aqueous solution. By wet pulverizing this aqueous solution with a bead mill (NAM-1 type manufactured by IMEX, zirconia beads, bead diameter: 0.2 mm), the center particle diameter D ₅₀ = 323 nm, the cumulative 99% diameter D ₉₉ = 947 nm, BET ratio. A 10% by mass slurry of submicron activated carbon having a surface area of 1100 m ^{2 / g was obtained.} This slurry was concentrated to 30% by mass using a compact disc dryer (manufactured by Nishimura Works Co., Ltd.). Cellulose nanofibers (Selenpia manufactured by Nippon Paper Industries, Ltd.) and ion-exchanged water were mixed with this concentrate according to the formulation shown in Table 1 to obtain a coating composition of submicron activated carbon.

Comparative Example 5
As a raw material activated carbon, coconut shell powder activated carbon (PGW-BF manufactured by Kuraray, center particle size D ₅₀ : 8 μm) was mixed with ion-exchanged water to prepare an 11% by mass aqueous solution. By wet pulverizing this aqueous solution with a bead mill (NAM-1 type manufactured by IMEX, zirconia beads, bead diameter: 0.2 mm), the center particle diameter D ₅₀ = 323 nm, the cumulative 99% diameter D ₉₉ = 947 nm, BET ratio. A coating composition of 11% by mass of submicron activated carbon having a surface area of 1100 m ^{2 / g was obtained.}

2. Viscosity measurement of coating composition The viscosity η (a) and η (b) and solid content concentration of the coating composition obtained in Examples 1 to 14 and Comparative Examples 1 to 5 are measured according to the following methods, respectively. did. The results are shown in Table 1. In addition, "-" in the column of viscosity in Table 1 means that measurement was not possible.

(1) Viscosity η (a)
Viscosity was measured using a B-type viscometer (Model DV-II + PRO viscometer manufactured by Brookfield, Spindle: SC4-34, Chamber: SC4-13R) at a shear rate of ^{20 ° C. and 5 × 10 -3} s ^-1.

(2) Viscosity η (b)
The viscosity was measured using a B-type viscometer (Model DV-II + PRO viscometer manufactured by Brookfield, Spindle: SC4-34, Chamber: SC4-13R) at a shear rate of ^{20 ° C. and 1s -1.}

(3) Solid content concentration The value calculated by dividing the total amount of the components charged excluding the liquid dispersion medium (solvent) at the time of preparing the coating composition by the total mass of the coating composition and multiplying by 100. Table 1 shows the solid content concentration.

3. 3. Characteristic evaluation of coating composition and coating film (1) Dispersibility test The coating compositions obtained in Examples 1 to 14, 16 and 17 and Comparative Examples 1 to 5 have an outer diameter of 25 mm and a height of 50 mm, respectively. The transparent container of the styrene screw bottle (manufactured by Maruem) was filled with 20 cc. After allowing this to stand for 24 hours, the dispersed state of the coating composition was visually confirmed and evaluated according to the following criteria. The results are shown in Table 2.
<Evaluation criteria>
⊚: Not settled at all ○: Settled to a height of 3/4 of the paint liquid height Δ: Settled to a height of 1/2 of the paint liquid height ×: 1 / of the paint liquid height It has settled to a height of 4.

(2) Sprayability and dripping evaluation The paint compositions obtained in Examples 1 to 14, 16 and 17 and Comparative Examples 1 to 5 were filled in commercially available rechargeable airbrushes, and the following tests were performed. .. The results are shown in Table 2.
The spray application is based on repeating spraying for about 1 second three times per push from a position 30 mm away from the object (a series of sprays is counted as one spray application). The coating range is a range in which the coating is concentrically applied in a radius of 10 to 15 mm from the center of the object to be coated. As the rechargeable airbrush, an airbrush having a maximum compressor pressure of 17.4 PSI, a discharge rate of 5 L / min, and a nozzle diameter of 0.3 mmφ was used.

(A) Sprayability Acrylic plates (Sumitomo Chemical Acrylic Sheet: SUMIPEX E) obtained by tilting the coating compositions obtained in Examples 1 to 14, 16 and 17 and Comparative Examples 1 to 5 at an angle of 45 ° from a horizontal plane. The upper surface of the water was spray-applied once. The spraying condition at that time was confirmed and evaluated according to the following criteria.
<Evaluation criteria>
⊚: No liquid clogging occurs ○: Slightly uneven spraying but no liquid clogging △: Intermittent liquid clogging occurs but spraying can be continued ×: Spraying is not possible due to liquid clogging

(B) Dripping test An acrylic plate (Sumitomo Chemical acrylic sheet: SUMPEX E) obtained by tilting the coating composition obtained in Examples 1 to 14, 16 and 17 and Comparative Examples 1 to 5 at an angle of 45 ° from a horizontal plane. ) Was spray-applied once, and 24 hours later, the degree of dripping of the paint was visually confirmed and evaluated according to the following criteria.
<Evaluation criteria>
⊚: No dripping at all ○: Dripping within 10 mm Δ: Dripping within 50 mm longer than 10 mm ×: Dripping over 50 mm

(3) Evaluation of spray unevenness and shedding property (c) Spray unevenness test Photographic paper obtained by tilting the coating composition obtained in Examples 1 to 14, 16 and 17 and Comparative Examples 1 to 5 at an angle of 45 ° from a horizontal plane. The surface of (Canon photographic paper made by Canon, glossy, thick: 0.27 mm, L version: 89 × 127 mm) was sprayed with a charging air spray so that the coating thickness became 20 to 40 μm and the thickness was as uniform as possible. After leaving these at room temperature for 24 hours, the degree of spray unevenness of the paint was visually confirmed and evaluated according to the following criteria.
<Evaluation criteria>
◎: No uneven spraying ○: Almost no uneven spraying △: Some uneven spraying ×: Uneven spraying

(D) Drop-off property test 2 g of each of the paint compositions obtained in Examples 1 to 14, 16 and 17 and Comparative Examples 1 to 5 was tilted at an angle of 45 ° from a horizontal plane (Canon photo paper made by Canon). -Glossy, thick: 0.27 mm, L plate: 89 x 127 mm) was sprayed with a charging air spray so that the coating thickness was 20 to 40 μm and the thickness was as uniform as possible. Further, as Example 15, the coating composition of Example 1 was spray-coated by the above method and sufficiently dried, and then 1 g of a 0.2 mass% cellulose nanofiber aqueous solution was applied onto the obtained coating film. A coating film was obtained by spray coating in the same manner as the method. After leaving these at room temperature for 24 hours, the dried coating film was touched by hand, and the degree of shedding of activated carbon was evaluated according to the following criteria. The results are shown in Table 2.
<Evaluation criteria>
◎: Does not adhere to the hand at all ○: Slightly adheres to the hand △: Adheres considerably to the hand ×: Drops off due to vibration

(4) Adsorption Performance Test 2 g of each of the paint compositions obtained in Examples 1 to 14, 16 and 17 and Comparative Examples 1 to 5 was tilted at an angle of 45 ° from a horizontal plane (Canon photographic paper made by Canon). -Glossy, thick: 0.27 mm, L plate: 89 x 127 mm) was sprayed with a charging air spray so that the coating thickness was as uniform as possible. Further, as Example 15, the coating composition of Example 1 was spray-coated by the above method and sufficiently dried, and then 1 g of a 0.2 mass% cellulose nanofiber aqueous solution was applied onto the obtained coating film. A coating film was obtained by spray coating in the same manner as the method. After allowing these to stand at room temperature for 24 hours, the adsorption performance was evaluated according to the following criteria by measuring the amount of benzene adsorbed on the photographic paper coated with the coating composition. The method for measuring the amount of benzene adsorbed is based on JIS K 1474. The results are shown in Table 2.
<Evaluation criteria>
⊚: 10% or more ○: 5% or more to less than 10% Δ: 1% or more to less than 5% ×: less than 1%

The coating compositions of Examples 1 to 14, 16 and 17 according to the present invention show good sprayability at the time of spraying, have an appropriate viscosity that prevents dripping after spraying, and ensure adsorption performance by activated carbon. However, it was confirmed that a thin, uniform and excellent appearance coating film having no or suppressed spray unevenness could be formed. On the other hand, when the central particle size of the activated carbon exceeds 1000 nm, the dispersibility is poor, and a thin, uniform and excellent coating film cannot be obtained (Comparative Examples 1 and 2). Further, as the amount of submicron activated carbon increased, the viscosity increased, the sprayability decreased, and the coating film could not be formed by air spray (Comparative Examples 3 to 5).

Claims (11)

1. A composition for paints containing activated carbon and a liquid dispersion medium.
   A coating composition in which the activated carbon is an activated carbon having a central particle size D ₅₀ of 1000 nm or less, and the content of the activated carbon is 1% by mass or more and 10% by mass or less with respect to the total mass of the coating composition.
2. The coating composition according to claim 1, further comprising cellulose nanofibers, wherein the mass ratio of cellulose nanofibers to activated carbon (cellulose nanofibers / activated carbon) is less than 0.4.
3. The coating composition according to claim 2, wherein the content of the cellulose nanofibers is 0.5% by mass or less with respect to the total mass of the coating composition.
4. Viscosity η (a) measured at 20 ° C. at a shear rate of ^{5 × 10 -3} s ^-1 using a B-type viscometer ^{is 8 × 10 2} mPa · s or more and 1.2 × 10 ⁴ mPa · s or less. The coating composition according to any one of claims 1 to 3.
5. The coating material according to any one of claims 1 to 4, wherein the viscosity η (b) measured at 20 ° C. at a shear rate of ^1s-1 using a B-type viscometer ^{is 3 × 10 2 mPa · s or less.} Composition for.
6. The coating composition according to any one of claims 1 to 5, further comprising an additive.
7. Additives are insect repellents, pesticides, antibacterial agents, dispersants, humidity control agents, photocatalyst materials, pigments, adsorbents other than activated charcoal, binders, resins, wetting agents, thickeners other than cellulose nanofibers, sedimentation prevention Agents, surface regulators, anti-skin agents, anti-dripping agents, leveling agents, anti-repellent agents, anti-armpit agents, curing catalysts, plasticizers, matting agents, anti-scratch agents, UV absorbers, light stabilizers, preservatives The paint according to claim 6, which comprises at least one selected from the group consisting of algae, antistatic agent, flame retardant, antifouling agent, antioxidant, pH adjuster, antifoaming agent and emulsifier. Composition.
8. The coating composition according to claim 6 or 7, wherein the content of the additive is 30% by mass or less with respect to the total mass of the coating composition.
9. The coating composition according to any one of claims 1 to 8, wherein the solid content concentration in the coating composition is 1% by mass or more and 20% by mass or less with respect to the total mass of the coating composition.
10. A step (1) of mixing a raw material activated charcoal having a central particle diameter D ₅₀ of 3 to 30 μm and a liquid dispersion medium so that the concentration of the raw material activated charcoal in the mixture is 1 to 30% by mass to obtain a mixture, and the above-mentioned step. The mixture obtained in (1) is wet-ground with a bead mill using zirconia beads having a particle size of 0.2 to 1 mm, _{and the activated charcoal having a central particle size D 50} of 1000 nm or less and a liquid dispersion medium are used. Step of obtaining a mixture of (2)
    The method for producing a coating composition according to any one of claims 1 to 9, which comprises.
11. A spray preparation containing the coating composition according to any one of claims 1 to 9.