Two-component polyurethane coating composition, method for producing the same, cured coating film, and substrate with cured coating film.

Abstract

To provide a 2-liquid type polyurethane-based coating composition that can form a cured coating film excellent in antiviral / antibacterial properties, coating film appearance, and touch feeling (soft feeling, smooth feeling).SOLUTION: A 2-liquid type polyurethane-based coating composition of the present invention is a 2-liquid type polyurethane-based coating composition that contains a first component containing (A) an antiviral or antibacterial agent, (B) a polyester polyol, (C) a leveling agent, and (D) a hydrophobic silica; and a second component containing (E) a polyisocyanate, and in which, characterized, the volume-based particle size distribution D50 of the particles in the first component is 5.0 μm or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a two-component polyurethane-based coating composition and a method for producing the same. The present invention also relates to a cured coating film formed from the two-component polyurethane-based coating composition and a substrate with the cured coating film having the cured coating film.

Background Art

[0002] Every year, along with the influenza epidemic, countermeasures against influenza are required in facilities such as stations, airports, hospitals, schools, etc. where many people come and go. In addition, in recent years, due to the spread of the novel coronavirus infection, the demand for antiviral agents and antiviral products has been further increasing.

[0003] In particular, in places where a large number of unspecified people touch, processing for imparting an antiviral effect and an antibacterial effect is desired for the purpose of preventing contact infection. However, materials such as plastics and metals such as iron (for example, doorknobs, handrails, various switches, etc.) have firmness and coldness when touched by hand, so processing for imparting a soft feeling and a smooth feeling is often desired. For example, in Patent Document 1, in order to form a coating film having a good touch feeling in which the properties of a soft feeling, a moist feeling, and a smooth feeling are compatible, it consists of a resin solution containing acrylic polyol and a curing agent solution containing polyisocyanate, and contains urethane resin beads and an organic matting agent in a specific blending amount. A two-component curable urethane coating composition has been proposed. Further, in Patent Document 2, a polyurethane resin composition containing a specific polyol, polyisocyanate, and matting agent has been proposed in order to form a coating film that achieves both chemical resistance and a soft touch. However, still, it has not been fully realized to impart an antiviral effect and an antibacterial effect while imparting a soft feeling and a smooth feeling.

Prior Art Documents

Patent Documents

[0004] [[ID=J27]]

Patent Document 1

[0005] Therefore, the object of the present invention is to provide a two-component polyurethane-based coating composition and a method for producing the same that can form a cured coating film with excellent antiviral and antibacterial properties, coating film appearance, and tactile feel (softness, smoothness). [Means for solving the problem]

[0006] As a result of diligent research, the inventors have found that the above problem can be solved by adjusting the volume-based particle size distribution D50 of the first component, which contains (A) an antiviral or antibacterial agent, (B) a polyester polyol, (C) a leveling agent, and (D) hydrophobic silica, to a specific range in a two-component polyurethane coating composition comprising a first component (main component) and a second component (curing agent component). The present invention was completed based on this finding.

[0007] In other words, the present invention provides the following invention. [1] A first component comprising (A) an antiviral or antibacterial agent, (B) a polyester polyol, (C) a leveling agent, and (D) hydrophobic silica, (E) The second component contains polyisocyanate and A two-component polyurethane coating composition containing, A two-component polyurethane coating composition wherein the volume-based particle size distribution D50 of the particles in the first component is 5.0 μm or less. [2] The two-component polyurethane coating composition according to [1], wherein the volume-based particle size distribution D90 of the particles in the first component is 10.0 μm or less. [3] (A) The two-component polyurethane coating composition according to [1] or [2], wherein the antiviral agent content is 1% by mass or more and 20% by mass or less based on 100% by mass of the solid content of the two-component polyurethane coating composition. [4] (D) A two-component polyurethane coating composition according to any one of [1] to [3], wherein the hydrophobic silica content is 1% by mass or more and 20% by mass or less based on 100% by mass of the solid content of the two-component polyurethane coating composition. [5] (E) A two-component polyurethane coating composition according to any one of [1] to [4], wherein the polyisocyanate is an aliphatic diisocyanate or an isocyanurate thereof. [6] A two-component polyurethane coating composition according to any one of [1] to [5], further comprising a catalyst. [7] A two-component polyurethane coating composition according to any one of [1] to [6], further comprising a dispersant. A cured coating film formed from a two-component polyurethane coating composition described in any of [8] [1] to [7]. [9] A substrate with a cured coating, the substrate having a cured coating film formed on at least one side of the substrate from a two-component polyurethane coating composition according to any one of [1] to [7].

[10] A substrate with a cured coating according to [9], wherein the haze value of the cured coating surface is 70% or more. A method for producing a two-component polyurethane coating composition, comprising the step of mixing the first component and the second component in any of the coating compositions described in [1] to [7]. [Effects of the Invention]

[0008] The present invention provides a two-component polyurethane-based coating composition and a method for producing the same, which can form a cured coating film with excellent antiviral and antibacterial properties, coating film appearance, and tactile feel (softness, smoothness). Furthermore, the present invention provides a substrate with a cured coating film that has excellent antiviral and antibacterial properties, coating film appearance, and tactile feel (softness, smoothness). [Modes for carrying out the invention]

[0009] The present invention will be described in more detail below. In this specification, "(meth)acrylate" refers to acrylate and methacrylate, and "(meth)acryloyl" refers to acryloyl and methacryloyl. "Solid content" refers to the components that make up the cured coating film when the two-component polyurethane paint composition is cured, excluding volatile components such as organic solvents.

[0010] <Two-component polyurethane-based paint composition> The two-component polyurethane coating composition according to the present invention includes a two-component polyurethane coating composition comprising a first component (main component) and a second component (curing agent component).

[0011] (Component 1) The first component comprises at least (A) an antiviral or antibacterial agent, (B) a polyester polyol, (C) a leveling agent, and (D) hydrophobic silica, and may further comprise a catalyst, a dispersant, a solvent, and other components.

[0012] The content of particulate components (antiviral agents, antibacterial agents, silica, etc.) in the first component is preferably 10% to 40% by mass, more preferably 12% to 35% by mass, and even more preferably 14% to 30% by mass, based on 100% by mass of the solid content of the first component. If the content of the particulate components is within the above numerical range, the dispersibility of the particulate components in the first component can be improved, and the antiviral and antibacterial properties of the cured coating film, the appearance of the coating film, and the feel (softness, smoothness) can be improved.

[0013] The volume-based particle size distribution D50 of the particles in the first component represents the particle size value at which the cumulative distribution from the smallest particle size side of the particles in the first component (antiviral agents, antibacterial agents, silica, etc.) reaches 50%, and the volume-based particle size distribution D90 represents the particle size value at which the cumulative distribution from the smallest particle size side of the particles in the first component (components A and D) reaches 90%, and can be measured by laser diffraction scattering. The first component has a volume-based particle size distribution D50 of 5.0 μm or less, preferably 0.5 μm to 5.0 μm, and more preferably 1.0 μm to 5.0 μm. Furthermore, the first component has a volume-based particle size distribution D90 of 10.0 μm or less, more preferably 5.0 μm to 10.0 μm, and even more preferably 6.0 μm to 10.0 μm. By adjusting the volume-based particle size distributions D50 and D90 of the particles in the first component to within the above range, the dispersibility of the antiviral or antibacterial agent in the first component can be improved, thereby enhancing the antiviral and antibacterial properties of the cured coating film, as well as its appearance and tactile feel (softness, smoothness). The values ​​of D50 and D90 can be adjusted to a desired range by adjusting the type and content of the leveling agent and dispersant in the first component.

[0014] (A) Antiviral or antibacterial agents Examples of antiviral agents include organic antiviral agents and inorganic antiviral agents. Examples of organic antiviral agents include azoles such as imidazole, triazole, thiazole and benzimidazole, triazines, halocarbans, chlorophenesin, lysozyme chloride, alkyldiaminoethylglycine hydrochloride, isopropylmethylphenol, thymol, hexachlorophene, berberine, thioxolone, salicylic acid and its derivatives, benzoic acid, sodium benzoate, parahydroxybenzoic acid esters, parachloromethacresol, benzalkonium chloride, phenoxyethanol, isopropylmethylphenol, carbolic acid, sorbic acid, sorbic acid Examples include potassium phosphate, hexachlorophene, chlorhexidine chloride, trichlorocarbanilide, thianthol, hinokitiol, triclosan, chlorhexidine gluconate, phenoxyethanol, resorcinol, azulene, salicylic acid, zinc pyrithione, mononitroguaiacol sodium, fennel extract, sansho pepper extract, cetylpyridinium chloride, benzethonium chloride and undecylenic acid derivatives, alkylbenzene sulfonic acid and its salts, bis-pyridinium salts, bis-quinolinium salts, bis-thiazolium salts, and phenyl ether derivatives. These organic antiviral agents may be used individually, in combination of two or more, or supported on inorganic materials.

[0015] In addition, as the inorganic antiviral agent, a metal compound, an inorganic ion exchanger carrying a metal ion, or the like can be used. Examples of the metal compound include metal oxides, inorganic phosphate compounds, and inorganic silicate compounds. Examples of the metal oxide include zinc oxide, silver oxide, and lead oxide. Examples of the inorganic phosphate compound include zinc phosphate, phosphate compounds of titanium group elements such as zirconium phosphate, hafnium phosphate, and titanium phosphate, aluminum phosphate, hydroxyapatite (phosphate mineral), and the like. Examples of the inorganic silicate compound include magnesium silicate, silica gel, aluminosilicate, sepiolite (magnesium hydrous silicate), montmorillonite (silicate mineral), zeolite (aluminosilicate), and the like. Examples of the metal ion include silver ion, copper ion, etc., and silver ion is preferred. Examples of the inorganic ion exchanger include zirconium phosphate, zeolite, and the like. These inorganic antiviral agents may be used alone or in combination of two or more kinds.

[0016] Examples of commercially available antiviral agents include, for example, "Vitecter IV" (manufactured by Sekisui Materials Solutions Co., Ltd.) and "Novaron IV-1000" (manufactured by Toagosei Co., Ltd.).

[0017] Based on 100% by mass of the solid content of the two-component polyurethane-based coating composition, the content of the antiviral agent is preferably 1% by mass or more and 20% by mass or less, more preferably 2% by mass or more and 15% by mass or less, and still more preferably 3% by mass or more and 10% by mass or less. Also, based on 100% by mass of the solid content of the first component, the content of the antiviral agent is preferably 1% by mass or more and 20% by mass or less, more preferably 3% by mass or more and 18% by mass or less, and still more preferably 5% by mass or more and 16% by mass or less. If the content of the antiviral agent is within the above numerical range, the dispersibility of the antiviral agent in the first component can be improved, and the antiviral property, coating film appearance, and touch feeling (soft feeling, smooth feeling) of the cured coating film can be improved.

[0018] Furthermore, the compounds exemplified above as antiviral agents (organic and inorganic antiviral agents) can also be used as antibacterial agents.

[0019] Examples of antibacterial agents include organic and inorganic antibacterial agents. Examples of organic antibacterial agents include imidazole, thiazole, isothiazolinine, and pyridine compounds. Examples of inorganic antibacterial agents include silver, zinc, and copper. Examples of metal compounds include molybdate compounds and carbonate compounds. Examples of molybdate compounds include silver molybdate, potassium molybdate, and magnesium molybdate. Examples of carbonate compounds include calcium carbonate and magnesium carbonate. These antibacterial agents may be used individually, in combination of two or more, or by supporting an organic antibacterial agent on an inorganic material.

[0020] Examples of commercially available antibacterial agents include "Zeomic AJ10N" (manufactured by Sinanen Zeomic Co., Ltd.) and "BioCut SV" (manufactured by Nippon Soda Co., Ltd.).

[0021] The antibacterial agent content is preferably 1% to 20% by mass, more preferably 2% to 15% by mass, and even more preferably 3% to 10% by mass, based on 100% by mass of the solid content of the two-component polyurethane coating composition. If the antibacterial agent content is within the above numerical range, the dispersibility of the antibacterial agent in the first component can be improved, and the antibacterial properties of the cured coating film, the appearance of the coating film, and the feel (softness, smoothness) can be improved.

[0022] (B) Polyester polyol As the polyester polyol, for example, those obtained by known methods such as polycondensation of a polyol with a dicarboxylic acid or dicarboxylic acid chloride, or esterification of a polyol or dicarboxylic acid followed by a transesterification reaction can be used. The polyester polyol may be used alone or in combination of two or more types.

[0023] The polyols used in the synthesis of polyester polyols are not particularly limited, but examples include diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, tetraethylene glycol, tetrapropylene glycol, and neopentyl glycol, as well as polyhydric alcohols with three or more functions, such as glycerin, diglycerin, trimethylolpropane, pentaerythritol, sorbitol, and sucrose. These polyols may be used individually or in combination of two or more.

[0024] The dicarboxylic acids used in the synthesis of polyester polyols are not particularly limited, but examples include adipic acid, succinic acid, glutaric acid, pimelic acid, sebacic acid, azelaic acid, dimaleic acid, terephthalic acid, isophthalic acid, and phthalic acid. These dicarboxylic acids may be used individually or in combination of two or more.

[0025] The polyester polyol preferably has a weight-average molecular weight (Mw) of 500 to 100,000, and more preferably 1,000 to 50,000. Furthermore, the polyester polyol preferably has a hydroxyl value of 30 to 240 mgKOH / g, and more preferably 50 to 180 mg / KOH.

[0026] The polyester polyol content is preferably 20% to 70% by mass, more preferably 25% to 65% by mass, and even more preferably 30% to 60% by mass, based on 100% by mass of the solid content of the two-component polyurethane coating composition. If the polyester polyol content is within the above numerical range, the appearance and tactile feel (softness) of the cured coating film can be improved.

[0027] (C) Leveling agent Examples of leveling agents include silicone-based leveling agents, fluorine-based leveling agents, and acrylic polymer-based leveling agents. Among these, silicone-based leveling agents are particularly preferred. These leveling agents may be used individually or in combination of two or more types.

[0028] As a silicone-based leveling agent, either straight silicone or modified silicone can be used. Examples of straight silicones include polydimethylsiloxane, polymethylphenylsiloxane, and polymethylhydrodienesiloxane. Modified silicone is obtained by introducing substituents of various organic groups into a part of the silicone. Examples of modified sites include at least one selected from the group consisting of polyester sites, polyether sites, acrylic resin sites, and carbinol sites. In this specification, acrylic resin includes polymers of acrylic acid esters and / or methacrylic acid esters. The modified site may be a single-ended, double-ended, side-chain, or side-chain-ended type of silicone chain. Examples of modified silicones include polyester-modified silicone, polyether-modified silicone, polyether-polyester-modified silicone, silicone-modified acrylic resin, and carbinol-modified silicone.

[0029] Examples of commercially available polyester-modified silicones include BYK-310, 313, and 315 (manufactured by Bic Chemie Japan Co., Ltd.). Examples of commercially available polyether-modified silicones include BYK-300, 302, 306, 307, 330, 331, 333, 342, and 378 (manufactured by Bic Chemie Japan Co., Ltd.).

[0030] Modified silicones preferably contain hydroxyl groups. The hydroxyl groups are preferably present in the modified areas, such as the polyester area, polyether area, acrylic resin area, and carbinol area. Examples of hydroxyl-containing modified silicones include hydroxyl-containing polyester modified silicone, hydroxyl-containing polyether modified silicone, hydroxyl-containing polyether-polyester modified silicone, hydroxyl-containing silicone modified acrylic resin, and carbinol modified silicone.

[0031] Examples of commercially available hydroxyl group-containing silicone-modified acrylic resins include BYK-SILCLEAN3700 (manufactured by Bic Chemie Japan Co., Ltd.), Cymac US-270 (manufactured by Toagosei Co., Ltd.), and ZX-028-G (manufactured by T&K TOKA Co., Ltd.). Examples of commercially available hydroxyl group-containing polyester-modified silicones include BYK-370 (manufactured by Bic Chemie Japan Co., Ltd.). Examples of commercially available hydroxyl group-containing polyether-modified silicones include BYK-377 (manufactured by Bic Chemie Japan Co., Ltd.).

[0032] Examples of fluorine-based leveling agents include fluorine-based leveling agents having a perfluoroalkenyl group in the main chain or side chain, such as perfluoroalkenyl carboxylates, perfluoroalkenyl sulfonates, perfluoroalkenyl phosphates, and perfluoroalkenyl betaines; and fluorine-based leveling agents having a perfluoroalkyl group in the main chain or side chain, such as perfluoroalkyl polyoxyethylene ethers, perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, perfluoroalkyl phosphates, and perfluoroalkyl betaines.

[0033] As an acrylic polymer-based leveling agent, for example, a polyether-modified (meth)acrylic compound represented by the following general formula (1) can be used. [ka] In general formula (1), R1 to R8 may be the same or different, at least one of R1 to R8 represents a polyether group represented by general formula (2), and at least one represents a (meth)acryloyl group or a C1 to C20 linear or branched alkyl group having a (meth)acryloyl group. [ka] In general formula (2), R9 is a linear or branched alkylene group of C1 to C20, R 10 R9 represents a hydrogen atom, a C1-C20 linear or branched alkyl group, a C2-C20 linear or branched alkenyl group, or a C2-C20 linear or branched alkynyl group. Multiple R9s may be the same or different. k represents an integer of 1 or more. The other R1-R8s represent C1-C20 linear or branched alkyl groups. Multiple R2-R5s may be the same or different. m and n may be the same or different, and represent integers greater than or equal to 0, preferably integers from 1 to 20, and more preferably integers from 1 to 10.

[0034] The leveling agent content is preferably 0.1% to 5% by mass, more preferably 0.2% to 2% by mass, and even more preferably 0.3% to 1% by mass, based on 100% by mass of the solid content of the two-component polyurethane coating composition. If the leveling agent content is within the above numerical range, the appearance and feel (softness, smoothness) of the cured coating film can be improved.

[0035] ((D) Hydrophobic silica) As hydrophobic silica, for example, silica particles that have been surface-treated with a hydrophobic agent such as an organosilane or silicone oil can be used. Examples of hydrophobic agents include hexamethyldisilazane, vinyltriethoxysilane, vinyltrimethoxysilane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilyl mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinylmethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, polydimethylsiloxane, methyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, and phenyl Examples of silicone oils include nitritexoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, hexadecyltriethoxysilane, hexadecyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 1,6-bis(trimethoxysilyl)hexane, trifluoropropyltrimethoxysilane, hydrolyzable group-containing siloxane, octamethylcyclotetrasiloxane, and other organic silanes, dimethyl silicone oils, alkyl-modified silicone oils (alkyl having, for example, 1 to 3 carbon atoms), γ-methylstyrene-modified silicone oil, chlorophenyl silicone oil, fluorine-modified silicone oil, methylhydrogen silicone oil, and other silicone oils.

[0036] As hydrophobic silica, commercially available products can also be used. Examples include ACEMATT3400 and ACEMATT3600 manufactured by Evonik Corporation.

[0037] The volume-based particle size distribution D50 of the hydrophobic silica secondary particles is not particularly limited, but is preferably 0.1 μm to 10 μm, more preferably 0.5 μm to 9 μm, and even more preferably 1 μm to 8 μm. The definition and measurement method of the volume-based particle size distribution D50 are as described above. If the volume-based particle size distribution D50 of the hydrophobic silica secondary particles is within the above range, the dispersibility of the hydrophobic silica particles in the first component can be improved, and the appearance and feel (softness, smoothness) of the cured coating film can be improved.

[0038] The hydrophobic silica content is preferably 1% to 20% by mass, more preferably 2% to 15% by mass, and even more preferably 3% to 10% by mass, based on 100% by mass of the solid content of the two-component polyurethane coating composition. Furthermore, the hydrophobic silica content is preferably 1% to 20% by mass, more preferably 3% to 18% by mass, and even more preferably 5% to 15% by mass, based on 100% by mass of the solid content of the first component. If the hydrophobic silica content is within the above numerical range, the dispersibility of hydrophobic silica particles in the first component can be improved, and the appearance and feel (softness, smoothness) of the cured coating film can be improved.

[0039] (Second component) The second component comprises at least (E) polyisocyanate and may further comprise solvents and other components.

[0040] (E) Polyisocyanate Examples of polyisocyanates (diisocyanates) containing two isocyanate groups include aliphatic diisocyanates such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHMDI), and 1,5-pentamethylene diisocyanate (PDI); alicyclic diisocyanates such as methylenebis(4-cyclohexyl isocyanate) (HMDI), isophorone diisocyanate (IPDI), 1,3-bis(isocyanatomethyl)cyclohexane (HXDI), and norbornene diisocyanate (NBDI); and aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate (monomeric / polymeric MDI), tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), and naphthalene diisocyanate (NDI). Polyisocyanates containing three or more isocyanate groups include adducts, bilets, and isocyanurates of these diisocyanates and aliphatic polyhydric alcohols. The aliphatic polyhydric alcohol used as the adduct preferably has 2 to 5 carbon atoms; examples include trimethylolpropane and glycerin. Among these, aliphatic diisocyanates or their isocyanurates are preferred, and hexamethylene diisocyanates or their isocyanurates are more preferred. These polyisocyanates may be used individually or in combination of two or more.

[0041] The polyisocyanate content is preferably such that there are 0.2 to 5.0 isocyanate groups of the polyisocyanate per hydroxyl group of the polyether polyol, more preferably 0.5 to 3.0, and even more preferably 0.7 to 2.0. When the proportions of polyether polyol and polyisocyanate are within the above range, the reactivity is good.

[0042] (catalyst) The catalyst is not particularly limited, and conventionally known catalysts can be used. Examples of catalysts include tin-based catalysts (butyltin carboxylate, trimethyltin laurate, dibutyltin dilaurate, etc.), lead-based catalysts (lead octoate, etc.), bismuth-based catalysts, zinc-based catalysts, aluminum-based catalysts, amine-based catalysts (triethylamine, N-ethylmorpholine, triethylenediamine, diazabicycloundecene, etc.). From the viewpoint of reactivity, tin-based catalysts are preferred. These catalysts may be used individually or in combination of two or more.

[0043] The catalyst content is preferably 0.01% to 1% by mass, and more preferably 0.1% to 0.5% by mass, based on 100% by mass of the solid content of the two-component polyurethane coating composition. When the catalyst content is within the above numerical range, a good balance is achieved between the reaction-promoting effect and the pot life, and workability is improved.

[0044] (Dispersant) Dispersants may be added to improve the dispersibility of particulate components in the first component and the two-component polyurethane coating composition. Dispersants are not particularly limited, but examples include various dispersants such as copolymers and copolymers having pigment adsorption groups such as carboxylic acids, phosphoric acid, and amines, and compatible chains such as fatty acids, polyamino acids, polyethers, polyesters, polyurethanes, and polyacrylates.

[0045] The dispersant content is preferably 0.1% to 5% by mass, and more preferably 0.2% to 3% by mass, based on 100% by mass of the solid content of the two-component polyurethane coating composition. Furthermore, the dispersant content is preferably 0.1% to 10% by mass, and more preferably 0.5% to 5% by mass, based on 100% by mass of the solid content of the first component.

[0046] (solvent) The solvents used for the first and second components are not particularly limited, and conventionally known organic solvents can be used as needed to adjust the solid content concentration of each component and the paint composition. Examples of solvents include aromatic hydrocarbons (e.g., toluene, xylene, and ethylbenzene), esters or ether esters (e.g., ethyl acetate, butyl acetate, and methoxybutyl acetate), ethers (e.g., diethyl ether, tetrahydrofuran, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, and diethylene glycol monoethyl ether), ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, di-n-butyl ketone, and cyclohexanone), alcohols (e.g., methanol, ethanol, n- or i-propanol, n-, i-, sec- or t-butanol, 2-ethylhexyl alcohol, and benzyl alcohol), amides (e.g., dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc.), sulfoxides (e.g., dimethyl sulfoxide), and mixtures of two or more of these solvents.

[0047] (Other ingredients) In addition to the above components, the two-component polyurethane coating composition of the present invention may further contain, as necessary, pigments, polymerization inhibitors, non-reactive diluents, defoaming agents, settling inhibitors, heat stabilizers, ultraviolet absorbers, light stabilizers, antifouling enhancers, substrate adhesion enhancers, photosensitizers, antistatic agents, antifungal agents, and plasticizers, to the extent that they do not impair the objectives of the present invention.

[0048] (Method for producing a two-component polyurethane coating composition) The method for producing the two-component polyurethane coating composition of the present invention comprises at least a step of mixing the first component and the second component. Prior to this step, there may be a step of preparing the first component and the second component separately. Each step can be performed using conventionally known equipment such as mixers, dispersers, and stirrers. Examples of such equipment include mixing and dispersing mills, mortar mixers, rolls, paint shakers, and homogenizers.

[0049] [Substrate with hardened coating] The cured coating substrate of the present invention has a cured coating on at least one side formed from the above-described two-component polyurethane coating composition. The cured coating may be applied to the entire surface of one side of the substrate, to only a part of one side, or to both sides of the substrate. When applied to only a part, the form of the cured coating is not particularly limited, and any form such as a sea-island-like sea area or island area, a grid pattern, or a mosaic pattern can be adopted without particular limitation.

[0050] (base material) The substrate is not particularly limited and can be any object to which the coating film is to be formed, such as plastic, wood (wood-based substrate), paper, metal, glass, ceramics, concrete, brick, pottery, etc.

[0051] Examples of plastics include various plastic substrates (e.g., films and molded articles formed from triacetylcellulose, polyethylene terephthalate (PET), diacetylcellulose, acetate butyrate cellulose, polyolefin, polyvinyl chloride, polyethersulfone, polyacrylic, polyurethane, polyester, polycarbonate, polysulfone, polyether, polymethylpentene, polyetherketone, (meth)acrylonitrile, etc.).

[0052] The thickness of the substrate is not particularly limited, but if the substrate is in the form of a film or plate, it is preferably 10 μm or more and 10 mm or less, and more preferably 50 μm or more and 5 mm or less.

[0053] The two-component polyurethane coating composition of the present invention can be used specifically on various products and equipment used in residences, public facilities (including medical facilities such as hospitals, nursing homes, childcare facilities such as kindergartens, educational facilities such as schools, parks, government offices, train stations, airports, etc.), public transportation, office buildings, department stores, entertainment facilities, various manufacturing facilities for pharmaceuticals, food, etc., restaurants, livestock facilities, etc. Specifically, examples include devices equipped with image display devices such as smartphones, personal computers, and tablet terminals, as well as protective films, styluses, and protective cases for such image display devices; electrical appliances such as vacuum cleaners and refrigerators; automotive interior parts such as steering wheels, dashboards, instrument panels, door handles, and various switches; interior materials such as flooring (including vinyl sheet flooring), joinery, wall materials, and ceiling materials; aluminum sashes, screen doors, and railings for balconies; outdoor equipment (including tent fabrics, metal parts, and plastic parts); various tiles; various buttons such as door handles, levers, faucets, handrails, straps, elevator buttons, and lighting buttons; toilet components such as toilets and toilet paper holders; bathroom components such as bathtubs and bathroom surfaces; kitchen and washroom components; benches, chairs, and play equipment—parts that people touch.

[0054] (cured coating) The cured coating film is formed from the above-described two-component polyurethane coating composition. The thickness of the cured coating film is not particularly limited, but from the viewpoint of maintaining long-term antiviral and antibacterial properties, it is preferably 1 μm to 100 μm, more preferably 3 μm to 70 μm, and even more preferably 5 μm to 50 μm. In this invention, the thickness of the cured coating film refers to the thickness of the cured coating film when its cross-section is observed with an optical microscope or a scanning electron microscope (SEM). When forming a coating film of such thickness, the desired thickness may be formed in a single application, or it may be formed in multiple applications.

[0055] When the cured coating film formed from the above two-component polyurethane coating composition has a thickness of 10 to 15 μm, the haze measured in accordance with JIS K 7136 is preferably 70% or more, and preferably 95% or less. If the haze of the cured coating film is within the above range, the uniformity of the coating film and the dispersibility of antiviral and antibacterial agents in the coating film are excellent.

[0056] <Method for manufacturing a substrate with a hardened coating> The cured coating substrate according to the present invention includes the steps of applying the above-mentioned two-component polyurethane coating composition to at least one side of the substrate (coating step) and heating the substrate after the coating to cure the composition (curing step).

[0057] (Coating process) The coating process involves applying the above-mentioned two-component polyurethane coating composition to at least one side of the substrate using a conventionally known method. Coating methods include spray coating, dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, and spin coating. Among these, spray coating and coating methods using gravure coaters or die coaters are preferred from the viewpoint of workability and productivity. The coating film thickness should be such that the above-mentioned cured film thickness is achieved after curing and drying.

[0058] (hardening process) The curing step involves heating the substrate after coating to cure the two-component polyurethane coating composition and form a cured coating film. The heating conditions are not particularly limited as long as the temperature and time are sufficient for the curing of the coating film to proceed, but are preferably 40 to 150°C, more preferably 50 to 130°C, and preferably 1 minute to 10 hours, more preferably 3 minutes to 5 hours. [Examples]

[0059] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0060] <Preparation of a two-component polyurethane coating composition> First, the following raw materials were prepared for the preparation of the two-component polyurethane coating composition. • Antiviral agent 1 (phenyl ether-based, volume-based particle size distribution D50 of secondary particles: 5.0 μm, manufactured by Sekisui Material Solutions Co., Ltd., product name: Willtaker IV) • Antiviral agent 2 (anionic, volume-based particle size distribution D50 of secondary particles: 3.0 μm, manufactured by Sekisui Material Solutions Co., Ltd., Wiltaker VM) • Antiviral agent 3 (quaternary ammonium salt and bromine compound, manufactured by Yamato Chemical Industry Co., Ltd., product name: Amolden JM) • Antiviral agent 4 (silver-based, manufactured by Toagosei Co., Ltd., particle size distribution D50 based on secondary particle volume: 1.0 μm, product name: Novalon IV-1000) • Antimicrobial agent 1 (silver-based and zeolite compound, volume-based particle size distribution D50 of secondary particles: 2.8 μm, manufactured by Sinanen Zeomic Co., Ltd., product name: Zeomic AJ10N) • Antibacterial agent 2 (silver-based, particle size distribution D50 of secondary particles based on volume: 3.3 μm, manufactured by Nippon Soda Co., Ltd., product name: BioCut SV) • Polyester polyol 1 (hydroxyl value 78-88 mg KOH / g, manufactured by DIC Corporation, product name: Barnock D7-885-NT) • Polyester polyol 2 (hydroxyl value 115-145 mg KOH / g, manufactured by DIC Corporation, product name: Barnock D6-439) • Silicone-based leveling agent (polydimethylsiloxane-modified acrylic resin, manufactured by BYK Chemie Japan Co., Ltd., product name: BYK-SILCLEAN3700) • Silica particles 1 (hydrophobic treatment (polydimethylsiloxane treatment), volume-based particle size distribution D50 of secondary particles: 7.5 μm, manufactured by Evonik Japan Co., Ltd., product name: ACEMATT3400) • Silica particles 2 (hydrophobic treatment (polydimethylsiloxane treatment), volume-based particle size distribution D50 of secondary particles: 5.0 μm, manufactured by Evonik Japan Co., Ltd., product name: ACEMATT3600) • Silica particles 3 (untreated, volume-based particle size distribution D50 of secondary particles: 3.5~4.3 μm, manufactured by Fuji Silicia Co., Ltd., product name: Silicia 350) • Silica particles 4 (untreated, volume-based particle size distribution D50 of secondary particles: 5.6~7.6 μm, manufactured by Fuji Silicia Co., Ltd., product name: Silicia 370) • Polyisocyanate (NCO 12%, isocyanurate derivative of hexamethylene diisocyanate, Asahi Kasei Chemicals Corporation, product name: Duranate TSE-100) • Catalyst: (Butyltin carboxylate, Showa Varnish Co., Ltd., product name: Grec TL) • Dispersant: (maleic anhydride copolymer, polyoxyalkylene monoalkyl ether, Kyoeisha Chemical Co., Ltd., product name: Floren G700) • Solvent: Butyl acetate

[0061] [Examples 1-7, Comparative Examples 1-6] <Preparation of a two-component polyurethane coating composition> The first component (main component) was prepared by mixing and stirring components (A) to (D), a catalyst, a dispersant, and a solvent using a homodisperser, according to the formulations shown in Table 1. The second component (curing agent component) was prepared by mixing and stirring component (E) and a solvent using a homodisperser, according to the formulations shown in Table 2. Subsequently, the first and second components were mixed and stirred according to the formulations shown in Table 3 to prepare a two-component polyurethane coating composition.

[0062] <Rating> (Dispersibility of particles in the first component) The dispersibility of the particles (components A and D) in each of the first components obtained above was evaluated visually according to the following evaluation criteria. The evaluation results are shown in Table 1. [Evaluation Criteria] ○: The particles were uniformly dispersed in the first component, indicating good particle dispersibility. ×: The particles were aggregated in the first component or not uniformly dispersed, resulting in poor particle dispersibility.

[0063] (Measurement of particle size distribution of the first component) The volume-based particle size distributions D50 and D90 of the particles in each of the first components prepared above were measured using a laser diffraction / scattering particle size distribution analyzer (Microtrac Bell Co., Ltd., model MT-3300II) under the following conditions: wet method (transmission), refractive index: 1.81, dispersion medium: butyl acetate, and ultrasound: none. The measurement results are shown in Table 1.

[0064] <Manufacturing of substrates with hardened coatings> The two-component polyurethane coating composition prepared above was applied once to a PET film (manufactured by Toyobo Co., Ltd., product name: Cosmoshine A4300, thickness 100 μm) so that the cured coating film was approximately 12 μm thick. The coating film was then cured by heating at 80°C for 1 hour to form a cured coating film, and a substrate with a cured coating film was manufactured.

[0065] (Haze measurement) The haze (Hz) of the cured coating surface of the substrates with cured coatings manufactured as described above was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., model number: NDH4000) in accordance with JIS K 7136. The measurement results are shown in Table 3. A haze value of 70% or higher was considered acceptable. Conversely, a haze value of less than 70% was considered unacceptable.

[0066] (Evaluation of the appearance of the cured coating) The cured coating-coated substrates manufactured as described above were visually inspected and evaluated according to the following evaluation criteria. The evaluation results are shown in Table 3. [Evaluation Criteria] ○: The coating surface was uniform, and there were no aggregated particles. ×: The coating surface was uneven, and aggregated particles were observed.

[0067] (Evaluation of the softness of the hardened coating) The softness of the cured coating-coated substrates manufactured as described above was evaluated based on the feel of the coating surface when touched by hand, according to the following evaluation criteria. The evaluation results are shown in Table 3. [Evaluation Criteria] ○: The softness was good. △: It had a slightly soft feel. ×: It lacked a soft feel.

[0068] (Evaluation of the smooth texture of the hardened coating) The cured coating-coated substrates manufactured as described above were evaluated for their smoothness based on the feel of the coating surface when touched by hand, according to the following evaluation criteria. The evaluation results are shown in Table 3. [Evaluation Criteria] ○: The texture was smooth and pleasant. △: It had a slightly smooth feel, but there was some snagging. ×: It didn't have a smooth, silky feel.

[0069] (Evaluation of the antiviral properties of cured coatings) The cured coating surface of the cured substrate manufactured as described above was measured for antiviral activity in accordance with ISO 21702 under the following conditions. Furthermore, the antiviral properties were evaluated according to the following evaluation criteria. A value of 2.0 or higher was considered acceptable. The measured values ​​and evaluation results are shown in Table 3. [Conditions for antiviral testing] For antiviral testing, influenza A virus (H3N2 type) and ATCC-VR1679 were used. Specifically, first, samples were prepared by cutting 5 cm squares of substrate with a cured coating and substrate without a cured coating (control sample). Next, the samples were placed in a petri dish, and the test virus solution (concentration: 1-5 × 10⁻¹⁶) was applied to its surface. 7 0.4 mL of PFU / mL was added, and a polyethylene film (4 cm square) was placed over it as a contact film, pressing lightly to ensure the test virus solution was evenly distributed across the film. The sample was then left to stand at 25°C for 24 hours. After 24 hours, the virus solution was washed out and collected using SCDLP medium. The washed-out solution was used to infect MDCK cells (canine kidney-derived cells), and the viral infectivity titer was measured by plaque assay to determine the antiviral activity value. [Evaluation Criteria] ○: The antiviral activity value was 2.0 or higher. ×: The antiviral activity value was less than 2.0.

[0070] (Evaluation of the antibacterial properties of the cured coating film) The antibacterial activity value of the cured coating surface of the substrate with the cured coating manufactured as described above was measured in accordance with JIS Z 2801 under the following conditions. Furthermore, the antibacterial properties were evaluated according to the following evaluation criteria. Substrates with an antibacterial activity value of 2.0 or higher were considered acceptable. The measured values ​​and evaluation results are shown in Table 3. [Conditions for antimicrobial testing] The antibacterial tests used Staphylococcus aureus (NBRC12732) and Escherichia coli (NBRC3972). Specifically, first, samples were prepared by cutting 5 cm squares of substrate with a cured coating and substrate without a cured coating (control sample). Next, the samples were placed in a petri dish, and test bacterial solution 1 (Staphylococcus aureus, concentration: 3.4 × 10⁴) was applied to its surface. 5 (Cells / mL), Test bacterial solution 2 (Escherichia coli concentration 4.9 × 10⁶) 5 0.4 mL of each test bacterial solution (cells / mL) was added dropwise, and a polyethylene film (4 cm square) was placed over it as an adhesive film. The film was then lightly pressed down to ensure that the test bacterial solutions 1 and 2 were evenly distributed. The samples were then left to stand at 25°C for 24 hours. After 24 hours, the number of viable bacteria collected was used to determine the antibacterial activity value using the agar plate culture method. [Evaluation Criteria] ○: The antibacterial activity value was 2.0 or higher. ×: The antibacterial activity value was less than 2.0.

[0071] [Table 1]

[0072] [Table 2]

[0073] [Table 3]

Claims

1. (A) A phenyl ether-based or silver-based antiviral agent or silver-based antibacterial agent, (B) a polyester polyol, (C) a leveling agent, and (D) hydrophobic silica are included in the first component, (E) The second component contains polyisocyanate and A two-component polyurethane coating composition containing, A two-component polyurethane coating composition wherein the volume-based particle size distribution D50 of the particles in the first component is 5.0 μm or less.

2. The two-component polyurethane coating composition according to claim 1, wherein the volume-based particle size distribution D90 of the particles in the first component is 10.0 μm or less.

3. (A) The two-component polyurethane coating composition according to claim 1, wherein the content of the antiviral agent is 1% by mass or more and 20% by mass or less based on 100% by mass of the solid content of the two-component polyurethane coating composition.

4. (A) The two-component polyurethane coating composition according to Claim 1, wherein the antibacterial agent content is 1% by mass or more and 20% by mass or less based on 100% by mass of the solid content of the two-component polyurethane coating composition.

5. (B) The content of polyester polyol is 20% by mass or more and 70% by mass or less based on 100% by mass of the solid content of the two-component polyurethane coating composition, according to Claim 1.

6. (C) The two-component polyurethane coating composition according to claim 1, wherein the content of the leveling agent is 0.1% by mass or more and 5% by mass or less based on 100% by mass of the solid content of the two-component polyurethane coating composition.

7. (D) The two-component polyurethane coating composition according to claim 1, wherein the content of hydrophobic silica is 1% by mass or more and 20% by mass or less based on 100% by mass of the solid content of the two-component polyurethane coating composition.

8. (E) The two-component polyurethane coating composition according to claim 1, wherein the polyisocyanate is an aliphatic diisocyanate or an isocyanurate thereof.

9. A two-component polyurethane coating composition according to claim 1, further comprising a catalyst.

10. A two-component polyurethane coating composition according to claim 1, further comprising a dispersant.

11. A cured coating film formed from a two-component polyurethane coating composition according to any one of claims 1 to 10.

12. A substrate with a cured coating, wherein at least one side of the substrate has a cured coating formed from a two-component polyurethane coating composition according to any one of claims 1 to 10.

13. A substrate with a cured coating according to claim 12, wherein the haze value of the cured coating surface is 70% or more.

14. A method for producing a two-component polyurethane-based coating composition, comprising the step of mixing at least the first component and the second component in the coating composition according to any one of claims 1 to 10.

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