Antifogging agent composition and antifogging article having antifogging coating film

Abstract

To provide an anti-fogging agent composition capable of forming an anti-fogging coating film excellent in transparency, adhesion and anti-fogging properties and excellent in appearance and anti-fogging properties after a moisture resistance test and repeated dew condensation resistance even in a thick film.SOLUTION: An antifogging agent composition containing a copolymer (A) and colloidal silica (B), wherein the copolymer (A) is a (meth) acrylate copolymer obtained from a monomer mixture, and the monomer mixture contains a (meth) acrylate monomer (a- 1) having an epoxy group, a monomer (a- 2) represented by the general formula (1), and a hydrophobic (meth) acrylate monomer (a- 3) having a hydrocarbon group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an antifogging agent composition and an antifogging article having an antifogging coating film. [Background technology]

[0002] In vehicle lighting fixtures such as automobile headlamps, high-humidity air may enter the lamp chamber, causing the lens to cool due to the outside air or rainfall, resulting in condensation of water on the inner surface, causing fogging. As a result, the brightness of the vehicle light may decrease and the aesthetic appearance of the lens surface may be impaired, causing discomfort to the user. To prevent such lens fogging, a method is known in which an anti-fog agent is applied to the area where fogging occurs to form an anti-fog coating film (Patent Documents 1 and 2). Anti-fog coating films are generally required to be transparent, water-resistant, and not drip when applied.

[0003] For example, Patent Documents 1 and 2 disclose antifogging agent compositions containing a specific copolymer and colloidal silica. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2022 / 176510 [Patent Document 2] International Publication No. 2023 / 054457 Summary of the Invention [Problem to be solved by the invention]

[0005] When a water film is formed on the surface of an anti-fog coating by water-soluble components such as surfactants, the water in the water film may flow off locally (a phenomenon known as dripping).Water-soluble components from the anti-fog coating are dissolved in the water film, and when dripping occurs and the water evaporates, the dissolved water-soluble components precipitate on the surface of the anti-fog coating, leaving traces of dripping, which causes problems with the appearance of vehicle lighting fixtures.

[0006] In recent years, the shapes of vehicle lamps have become more complex from the perspective of design, and as a result, the internal shapes of vehicle lamps have also become more complex, making it easier for air to stagnate inside the vehicle lamp. As a result, if high-humidity air enters the lamp chamber, the interior of the vehicle lamp is exposed to a high-humidity environment for a long period of time. This increases the frequency of condensation on the inner surface of the lens, which cools down as described above. Furthermore, as the shapes of vehicle lamps have become more complex, the lens shapes have also become more complex, and when an anti-fog agent is applied, it does not form a uniform thin film, but rather the anti-fog coating film becomes thick in some areas.

[0007] The anti-fog agent composition disclosed in Patent Document 1 suppresses the occurrence of water drip marks by combining colloidal silica with a non-thermosetting acrylic copolymer. However, when the anti-fog coating film is thick, the acrylic copolymer is highly hydrophilic, and therefore elutes over time in a high humidity environment, resulting in a problem of deterioration in the appearance of the anti-fog coating film.

[0008] Furthermore, the anti-fog agent composition disclosed in Patent Document 2 suppresses the formation of water drip marks by combining colloidal silica with a thermosetting acrylic copolymer. However, when the anti-fog coating film is thick, repeated occurrence of water drips and evaporation of water causes the dissolved curing catalyst to precipitate on the surface of the anti-fog coating film, resulting in a problem of reduced transparency of the coating film.

[0009] In addition, the LED light sources used in vehicle lighting are so bright that even minor defects in appearance are visible, so there is a strong demand for maintaining the aesthetic appearance of the lens surface.

[0010] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an antifogging agent composition which is capable of forming an antifogging coating film which is excellent in transparency, adhesion and antifogging properties, and which is excellent in appearance after a moisture resistance test, antifogging properties and resistance to repeated condensation, even in a thick film. [Means for solving the problem]

[0011] That is, the present invention comprises the following configurations. [1] A composition comprising a copolymer (A) and colloidal silica (B), wherein the copolymer (A) is a (meth)acrylate copolymer obtained from a monomer mixture; The monomer mixture contains a (meth)acrylate monomer (A-1) having an epoxy group, a hydroxyl group represented by the general formula (1): [ka] (In general formula (1), R 1 is a hydrogen atom or a methyl group, and R 2 and R 3 are independently a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.) and a hydrophobic (meth)acrylate monomer (A-3) having a hydrocarbon group. [2] The anti-fogging agent composition according to [1], wherein the hydrocarbon group in the monomer (A-3) is preferably at least one functional group selected from the group consisting of a branched chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. [3] The anti-fogging agent composition according to [1] or [2], wherein the mass ratio of the monomer (A-1) to the monomer (A-2) [(A-1) / (A-2)] is preferably 0.3 to 3.0. [4] An anti-fogging article having an anti-fogging coating film formed from the anti-fogging agent composition according to any one of [1] to [3]. [Effects of the Invention]

[0012] Although the details of the mechanism of action of the antifogging agent composition of the present invention are partially unknown, it is presumed as follows.

[0013] The anti-fogging agent composition of the present invention contains a copolymer (A) and colloidal silica (B). The copolymer (A) contains the monomers (A-1) to (A-3). Therefore, the copolymer (A) and the colloidal silica (B) form a strong anti-fogging coating film via non-covalent or covalent bonds, primarily due to the monomer (A-1). This improves the moisture resistance of the anti-fogging coating film. The anti-fogging properties of the anti-fogging coating film are enhanced due to the monomer (A-2). The adhesion performance to a base resin substrate (e.g., polycarbonate) is exhibited by the monomer (A-3). The colloidal silica (B) improves the hydrophilicity (anti-fogging properties) of the anti-fogging coating film due to the hydrophilic groups on the silica surface and inside. Furthermore, after film formation, the interparticle cohesion between the silica particles reduces the water solubility of the anti-fogging coating film, thereby exhibiting the ability to enhance moisture resistance. DETAILED DESCRIPTION OF THE INVENTION

[0014] The antifogging agent composition of the present invention contains a copolymer (A) and colloidal silica (B).

[0015] <Copolymer (A)> The copolymer (A) of the present invention is a (meth)acrylate copolymer obtained from a monomer mixture containing the following monomer (A-1), monomer (A-2), and monomer (A-3).

[0016] <Monomer (A-1)> The monomer (A-1) is a (meth)acrylate monomer having an epoxy group. The (meth)acrylate monomer having an epoxy group may be a (meth)acrylate monomer having an epoxy ring at the molecular terminal, and preferred examples thereof include monomers represented by the following general formulas (2) to (3). [ka] (In general formula (2), R 4 is a hydrogen atom or a methyl group, R 5 is a straight or branched alkylene group having 1 to 8 carbon atoms. [ka] (In general formula (3), R 6 is a hydrogen atom or a methyl group, R 7 is a straight or branched alkylene group having 1 to 8 carbon atoms.

[0017] Among the general formulas (2) and (3), from the viewpoint of excellent anti-fogging properties and adhesion between the anti-fogging coating film and the substrate, R 4 is a hydrogen atom or a methyl group, R 5 is a linear or branched alkylene group having 1 to 4 carbon atoms, and as the general formula (3), R 6 is a hydrogen atom or a methyl group, R 7 is preferably a monomer in which is a linear or branched alkylene group having 1 to 4 carbon atoms. At least one type of the monomer (A-1) may be used, and two or more types may be used in combination.

[0018] <Monomer (A-2)> The monomer (A-2) is represented by the general formula (1): [ka] (In general formula (1), R 1 is a hydrogen atom or a methyl group, and R 2 and R 3 are independently a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.

[0019] The monomer (A-2) mainly functions to increase the hydrophilicity of the copolymer (A) and to enhance the anti-fogging properties of the anti-fogging coating film.

[0020] Among the compounds represented by the general formula (1), from the viewpoint of excellent anti-fogging properties and adhesion between the anti-fogging coating film and the substrate, R 1 is a hydrogen atom, R 2 and R 3 is preferably a methyl group or an ethyl group.

[0021] Examples of the monomer (A-2) include (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-normal propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and N,N-dimethyl(meth)acrylamide (R 1 =H or CH3, R 2 =CH3, R 3 =CH3), N,N-diethyl(meth)acrylamide (R 1 =H or CH3, R 2 =C2H5,R 3 =C2H5) and the like. At least one type of the monomer (A-2) may be used, and two or more types may be used in combination.

[0022] <Monomer (A-3)> The monomer (A-3) is a hydrophobic (meth)acrylate monomer having a hydrocarbon group, and the main function of the monomer (A-3) is to improve the adhesion between the anti-fog coating film and the substrate.

[0023] Examples of the hydrocarbon group in the monomer (A-3) include chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. Among these, from the viewpoint of excellent anti-fogging properties and adhesion between the anti-fogging coating film and the substrate, chain hydrocarbon groups having a branched structure, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups are preferred.

[0024] The number of carbon atoms in the branched chain hydrocarbon group is preferably 3 to 18, and more preferably 3 to 8. Examples of the (meth)acrylate monomer having a branched chain hydrocarbon group include isopropyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.

[0025] The alicyclic hydrocarbon group may be monocyclic or polycyclic, and the number of carbon atoms in the alicyclic hydrocarbon group is preferably 6 to 11. Examples of the (meth)acrylate monomer having an alicyclic hydrocarbon group include cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and adamantyl (meth)acrylate.

[0026] Examples of the (meth)acrylate monomer having an aromatic hydrocarbon group include phenoxy (meth)acrylate, 4-hydroxyphenoxy (meth)acrylate, benzyl (meth)acrylate, phenylethyl (meth)acrylate, and phenoxyethyl (meth)acrylate.

[0027] The monomer (A-3) may be used alone or in combination of two or more.

[0028] The monomer mixture may contain, as other monomers in addition to the monomers (A-1) to (A-3), aromatic vinyl monomers such as styrene, vinyltoluene, and α-methylstyrene; vinyl monomers containing quaternary ammonium salts such as (meth)acryloyloxyethyltrimethylammonium chloride and (meth)acryloylaminopropyltrimethylammonium chloride; [3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]methyl (meth)acrylate; 2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]methyl (meth)acrylate; UV-absorbing group-containing acrylic monomers such as [(2-methyl-2-yl)-4-hydroxyphenyl]ethyl (meth)acrylate; light-stable group-containing acrylic monomers such as 2,2,6,6-tetramethylpiperidyl methacrylate and 1,2,2,6,6-pentamethylpiperidyl methacrylate; carboxyl group-containing monomers such as methacrylic acid, itaconic acid, crotonic acid, and maleic acid, and their ammonium salts, organic amine salts, and alkali metal salts; styrene sulfonic acid, vinyl sulfonic acid, methallyl sulfonic acid, 2-(meth)acrylic acid Sulfonic acid group-containing vinyl monomers such as mido-2-methylpropanesulfonic acid and 3-sulfopropyl (meth)acrylate, and their ammonium salts, organic amine salts, and alkali metal salts; phosphate group-containing vinyl monomers such as 2-(meth)acryloyloxyethyl acid phosphate, and their ammonium salts, organic amine salts, and alkali metal salts; 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol (meth)acrylate, 1,10-decanediol di(meth)acrylate, neopentyl Examples of suitable monomers that can be used include bifunctional acrylic monomers such as glycol di(meth)acrylate and glycerin di(meth)acrylate; alkoxysilyl group-containing vinyl monomers such as γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropyltriethoxysilane and vinyltrimethoxysilane; amino group-containing vinyl monomers such as dimethylaminopropyl(meth)acrylamide and dimethylaminoethyl(meth)acrylate; (meth)acryloylmorpholine and diacetone(meth)acrylamide.

[0029] The proportions of the individual monomer components in the monomer mixture forming the copolymer (A) of the present invention will be described below.

[0030] The proportion of the monomer (A-1) in the monomer mixture is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more, from the viewpoint of improving the moisture resistance of the anti-fog coating film by forming a strong anti-fog coating film through non-covalent or covalent bonds between the copolymer (A) and the colloidal silica (B). The proportion of the monomer (A-1) in the monomer mixture is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less, from the viewpoint of improving the transparency of the anti-fog coating film. That is, the proportion of the monomer (A-1) in the monomer mixture is preferably 20% by mass or more and 60% by mass or less, more preferably 25% by mass or more and 55% by mass or less, and even more preferably 30% by mass or more and 50% by mass or less, from the viewpoint of improving the anti-fog properties of the copolymer and the transparency and moisture resistance of the anti-fog coating film.

[0031] From the viewpoint of enhancing the antifogging properties of the anti-fog coating film, the proportion of the monomer (A-2) in the monomer mixture is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more. From the viewpoint of enhancing the moisture resistance of the anti-fog coating film, the proportion of the monomer (A-2) in the monomer mixture is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less. That is, from the viewpoint of enhancing the antifogging properties and moisture resistance of the anti-fog coating film, the proportion of the monomer (A-2) in the monomer mixture is preferably 20% by mass or more and 60% by mass or less, more preferably 25% by mass or more and 55% by mass or less, and even more preferably 30% by mass or more and 50% by mass or less.

[0032] The proportion of the monomer (A-3) in the monomer mixture is preferably 3% by mass or more, and more preferably 5% by mass or more, from the viewpoint of improving the adhesion between the anti-fog coating film and the substrate. The proportion of the monomer (A-3) in the monomer mixture is preferably 35% by mass or less, and more preferably 30% by mass or less, from the viewpoint of improving the transparency of the anti-fog coating film. That is, the proportion of the monomer (A-3) in the monomer mixture is preferably 3% by mass or more and 35% by mass or less, and more preferably 5% by mass or more and 30% by mass or less, from the viewpoint of improving the transparency of the anti-fog coating film and its adhesion to the substrate.

[0033] The mass ratio of the monomer (A-1) to the monomer (A-2) [(A-1) / (A-2)] is preferably 0.3 to 3.0. From the viewpoint of improving the moisture resistance of the anti-fog coating film, the mass ratio of the monomer (A-1) to the monomer (A-2) [(A-1) / (A-2)] is more preferably 0.4 or more, even more preferably 0.5 or more, and even more preferably 0.6 or more. Furthermore, from the viewpoint of improving the anti-fog properties of the coating film, the mass ratio of the monomer (A-1) to the monomer (A-2) [(A-1) / (A-2)] is more preferably 2.5 or less, even more preferably 2.0 or less, and even more preferably 1.4 or less.

[0034] In the monomer mixture, the total proportion of the monomer (A-1), the monomer (A-2), and the monomer (A-3) is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0035] <Method for producing copolymer (A)> The copolymer is obtained by copolymerizing the monomer mixture. The copolymer structure may be any of a random copolymer, an alternating copolymer, a block copolymer, and a graft copolymer. However, a random copolymer is preferred from the viewpoints of improving the effects of the antifogging agent composition, including antifogging properties, and of easily preparing the antifogging agent composition. Various known polymerization methods, such as radical polymerization, cationic polymerization, anionic living polymerization, and cationic living polymerization, are used as the polymerization method for obtaining the copolymer. Radical polymerization is particularly preferred from the viewpoints of ease of industrial productivity and versatile performance. Examples of radical polymerization methods include conventional bulk polymerization, suspension polymerization, solution polymerization, and emulsion polymerization. Solution polymerization is preferred because the polymerized product can be used as an antifogging agent composition directly.

[0036] Examples of polymerization solvents used in the solution polymerization method include water, alcohol-based solvents such as methanol, ethanol, 1-propanol, 2-propanol, and diacetone alcohol; alcohol ether-based solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, 3-methoxybutanol, and 3-methoxy-3-methylbutanol; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether-based solvents such as tetrahydrofuran and dioxane; ester-based solvents such as methyl acetate, ethyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate, methyl lactate, and ethyl lactate; aromatic solvents such as benzene, toluene, and xylene; and amide-based solvents such as formamide and dimethylformamide. Among these, water, alcohol-based solvents, and alcohol ether-based solvents are preferred. The polymerization solvents may be used alone or in combination of two or more.

[0037] The radical polymerization initiator may be a commonly used organic peroxide, azo compound, or the like. Examples of the organic peroxide include benzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxy-2-hexanoate, t-butylperoxypivalate, and t-hexylperoxypivalate. Examples of the azo compound include 2,2'-azobisisobutyronitrile and 2,2'-azobis-2-methylbutyronitrile. The radical polymerization initiator may be used alone or in combination of two or more.

[0038] The amount of the radical polymerization initiator added is preferably 0.01 to 5 parts by mass relative to 100 parts by mass of the monomer mixture. The polymerization is preferably carried out while the radical polymerization initiator is added dropwise to a reaction vessel, as this makes it easier to control the heat generated by polymerization. The temperature at which the polymerization reaction is carried out varies depending on the type of radical polymerization initiator used, but is preferably 30 to 150°C, more preferably 40 to 100°C, for industrial production.

[0039] <Colloidal Silica (B)> The colloidal silica (B) of the present invention has the effect of improving anti-fogging properties mainly due to the hydrophilic groups on the surface and inside of the silica, and also has the function of reducing the water solubility of the anti-fogging coating film after film formation due to the cohesive force between silica particles, thereby making it difficult for water drip marks to form and increasing water resistance.

[0040] The colloidal silica (B) is a colloidal state in which silica particles represented by the chemical formula SiO2 are dispersed in a medium. Examples of the solvent include methanol, ethanol, 2-propanol, 1-butanol, xylene, dimethylformamide, and water. Among these, methanol, ethanol, 2-propanol, and water are preferred, and 2-propanol and water are more preferred. The colloidal silica (B) may also be silica particles whose surfaces are modified with a surface treatment agent such as a silane compound. At least one type of colloidal silica (B) may be used, or two or more types may be used in combination.

[0041] The colloidal silica (B) preferably has an average particle size of 5 to 100 nm, more preferably 5 to 30 nm. The average particle size is the average primary particle size and is expressed as the median diameter (D50) of the volume-based particle size distribution measured by dynamic light scattering. If the average particle size is less than 5 nm, the adhesion of the resulting anti-fog coating film to the substrate tends to decrease, while if it exceeds 100 nm, the transparency of the resulting anti-fog coating film tends to decrease. The shape of the colloidal silica (B) may be spherical, oblong, chain-like, pearl necklace-like, or the like.

[0042] Commercially available colloidal silica (B) includes, for example, trade names such as "Snowtex-XS", "Snowtex-S", "Snowtex-30", "Snowtex-50-T", "Snowtex-30L", "Snowtex-YL", "Snowtex-ZL", "Snowtex-MP-1040", "Snowtex-UP", "Snowtex-PS-S", "Snowtex-PS-M", "Snowtex-OXS", "Snowtex-OS", "Snowtex-O", "Snowtex-O-40", "Snowtex-OL", "Snowtex-OYL", "Snowtex-OUP", "Snowtex-PS-SO", and "Snowtex-PS-S". Examples of suitable silica sols include NOTTEX-PS-MO, NOTTEX-NXS, NOTTEX-NS, NOTTEX-N, NOTTEX-N-40, NOTTEX-CXS, NOTTEX-C, NOTTEX-CM, NOTTEX-AK, NOTTEX-AK-L, NOTTEX-AK-Y, NOTTEX-M, NOTTEX-M, NOTTEX-L, NOTTEX-IPA-ST, NOTTEX-L, NOTTEX-ZL, NOTTEX-UP, NOTTEX-EG-ST, NOTTEX-NPC-ST-30, NOTTEX-PGM-ST, and NOTTEX-DMAC-ST (all manufactured by Nissan Chemical Industries, Ltd.). Among these, "Snowtex-O," "Snowtex-O-40," "Snowtex-OL," "Snowtex-OYL," "Snowtex-N," "Snowtex-N-40," "methanol silica sol," "MA-ST-M," "MA-ST-L," "IPA-ST," "IPA-ST-L," and "IPA-ST-ZL" are preferred, which have an average particle size of 10 to 100 nm, are particulate, and use water or a monohydric alcohol having 1 to 4 carbon atoms as a dispersion medium; and "Snowtex-O," "Snowtex-OS," "Snowtex-O-40," "Snowtex-N," "Snowtex-N-40," "methanol silica sol," "MA-ST-M," and "IPA-ST" are more preferred, which have an average particle size of 5 to 30 nm, are particulate, and use water or a monohydric alcohol having 1 to 4 carbon atoms as a dispersion medium.

[0043] The content of the colloidal silica (B) is preferably 150 to 750 parts by mass per 100 parts by mass of the copolymer (A). From the viewpoint of improving the anti-fogging properties of the anti-fog coating film, the content of the colloidal silica (B) is more preferably 250 parts by mass or more per 100 parts by mass of the copolymer (A). From the viewpoint of improving the adhesion between the anti-fog coating film and the substrate, the content of the colloidal silica (B) is more preferably 500 parts by mass or less per 100 parts by mass of the copolymer (A). That is, from the viewpoint of improving the transparency of the anti-fog coating film and the adhesion to the substrate, the content of the colloidal silica (B) is more preferably 250 parts by mass or more and 500 parts by mass or less in the monomer mixture.

[0044] The total proportion of the copolymer (A) and the colloidal silica (B) in the solid content of the antifogging agent composition is preferably 60 mass% or more, more preferably 70 mass% or more, even more preferably 80 mass% or more, and even more preferably 90 mass% or more.

[0045] The anti-fogging agent composition is generally produced by adding a solvent to dissolve, disperse, or dilute a solution of the copolymer obtained by copolymerizing the above-mentioned monomers in order to adjust the viscosity to a level suitable for coating. Regarding the solvent added to the copolymer solution, a solvent with an extremely high boiling point may impair the adhesion of the coating film to the substrate due to residual solvent remaining during drying and heat curing of the coating film, so it is preferable to use a solvent with a boiling point of less than 180°C.

[0046] Examples of the solvent include alcohol-based solvents such as methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, 2-butanol, t-butanol, and diacetone alcohol; alcohol ether-based solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, 3-methoxy-1-butanol, and 3-methoxy-3-methyl-1-butanol; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether-based solvents such as tetrahydrofuran and dioxane; ester-based solvents such as methyl acetate, ethyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate, methyl lactate, and ethyl lactate; aromatic solvents such as benzene, toluene, and xylene; amide-based solvents such as formamide and dimethylformamide; hydrocarbon-based solvents such as n-hexane, cyclohexane, n-heptane, n-octane, and n-decane; and water. These solvents may be used alone or in combination of two or more.

[0047] A leveling agent may be added to the anti-fogging composition of the present invention from the viewpoint of making the surface of the anti-fogging coating film smoother.

[0048] Examples of the leveling agent include acrylic polymers, modified silicones, modified siloxanes, polyether macromer-modified acrylates, etc. Among these, silicones modified with a hydrophilic functional group such as polyether are preferred from the viewpoint of not impairing anti-fogging performance.

[0049] Commercially available leveling agents include, for example, those under the trade names "BYK-300", "BYK-320", "BYK-306", "BYK-307", "BYK-310", "BYK-313", "BYK-315N", "BYK-320", "BYK-322", "BYK-323", "BYK-325", "BYK-330", "BYK-331", "BYK-333", "BYK-342", "BYK-345 / 346", and "B YK-347, BYK-348, BYK-349, BYK-370, BYK-377, BYK-378, BYK-3455, BYK-3560, BYK-3565, BYK-3566 (all manufactured by BYK-Chemie Co., Ltd.), trade names: KP-323, KP-341, KP-104, KP-110, KP-112, KF-351A, KF-352A, KF-3 53", "KF-354L", "KF-355A", "KF-651A", "KF-945", "KF-640", "KF-642" (all manufactured by Shin-Etsu Silicone Co., Ltd.), product names: "Disparlon 1970", "Disparlon 230", "Disparlon 1711EF", "Disparlon 1761", "Disparlon LS-001", "Disparlon LS-050", "Disparlon LS-460", "Disparlon LS-48 0" (all manufactured by Kusumoto Chemical Co., Ltd.), trade names: "Polyflow WS", "Polyflow WS-314", "Polyflow KL-401", "Polyflow KL-402", "Polyflow KL-403", "Polyflow KL-404", "Polyflow KL-100", "Polyflow KL-850", "Polyflow KL-900", "LE-604", "LE-605", and "LE-606" (all manufactured by Kyoeisha Chemical Co., Ltd.). The leveling agents may be used alone or in combination of two or more.

[0050] When the leveling agent is used, the amount of the leveling agent is preferably 0.01 parts by mass or more and 10 parts by mass or less, more preferably 0.05 parts by mass or more and 5 parts by mass or less, and even more preferably 0.1 parts by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the copolymer (A).

[0051] In addition to the above-mentioned components, the antifogging composition of the present invention may contain, as other components, various conventional additives such as surfactants, antioxidants, ultraviolet absorbers, light stabilizers, etc., as needed, within the range that does not deteriorate the antifogging performance. The amount of the other components added may be the conventional amount for each additive, but is usually preferably 5.0 parts by mass or less per 100 parts by mass of the total of the copolymer (A) and the colloidal silica (B).

[0052] <Anti-fog articles> The anti-fog article of the present invention is one in which the anti-fog agent composition is applied to a substrate (substrate) by a coating method commonly used for coatings, and then heat-cured to form an anti-fog coating film on the surface of the substrate (substrate). A preliminary drying step can be carried out before the heat-curing step in order to volatilize and dry the solvent contained in the anti-fog coating film immediately after application.

[0053] The substrate (object to be coated) may be of any type and is not particularly limited, and examples thereof include resin substrates such as polymethyl methacrylate resin, polycarbonate resin, polystyrene resin, acrylonitrile-styrene copolymer resin, polyvinyl chloride resin, acetate resin, ABS resin, polyester resin, and polyamide resin; inorganic substrates such as glass; etc. The shape of the substrate is also not limited, and examples thereof include films, sheets, and three-dimensional molded products.

[0054] When applying the anti-fog agent composition to the substrate (object to be coated), it is preferable to remove any foreign matter adhering to the surface of the substrate (object to be coated) before application in order to increase the wettability of the anti-fog agent composition to the substrate (object to be coated) and prevent repellency. Examples of methods include dust removal using high-pressure air or ionized air, ultrasonic cleaning with a detergent aqueous solution or an alcohol solvent, wiping using an alcohol solvent, and cleaning with ultraviolet light and ozone. Examples of application methods include dipping, flow coating, roll coating, bar coating, and spray coating.

[0055] The pre-drying is usually carried out at a temperature of 20 to 50° C. for 0.5 to 10 minutes.

[0056] When the substrate is a resin member, the heating temperature is preferably set to a value equal to or lower than the thermal distortion temperature of the resin member. The heating time is affected by the heating temperature and should be set appropriately. For example, when the heating temperature is 80°C, the heating time is preferably 10 minutes or more, more preferably 15 minutes or more, and when the heating temperature is 130°C, the heating time is preferably 5 minutes or more, more preferably 10 minutes or more.

[0057] The thickness of the anti-fog coating film is preferably 0.5 μm or more, more preferably 1 μm or more, from the viewpoint of improving adhesion after pre-drying when a thin film is applied, and is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 7 μm or less, from the viewpoint of suppressing cracking when a thick film is applied and suppressing dripping during application.

[0058] The anti-fogging article is more suitable for use in an environment where condensation is likely to occur, and its use is not limited in any way. Examples of the anti-fogging article include automotive vehicle lighting fixtures (headlights, auxiliary headlights, width lights, license plate lights, tail lights, parking lights, back-up lights, turn signals, auxiliary turn signals, emergency flashers, etc.), eyeglasses, windows, mirrors, etc. [Example]

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

[0060] Example 1 <Production of Copolymer (A)> A reaction vessel equipped with a thermometer, stirrer, nitrogen inlet tube, and condenser was charged with 120 parts by weight of 1-propanol as a solvent, 40 parts by weight of glycidyl methacrylate (GMA) as monomer (A-1), 50 parts by weight of N,N-dimethylacrylamide (DMAA) as monomer (A-2), and 10 parts by weight of t-butyl methacrylate (TBMA) as monomer (A-3), and heated to 75°C while blowing in nitrogen gas. A solution of 0.6 parts by weight of a hydrocarbon-diluted radical polymerization initiator, t-hexyl peroxyneodecanate (trade name: Perhexyl ND, manufactured by NOF Corporation), dissolved in 30 parts by weight of 1-propanol, was added dropwise over 3 hours. Polymerization was continued for another 2 hours, yielding a solution of copolymer (A) of Example 1 with a copolymer concentration of 40% by weight.

[0061] <Production of Antifogging Agent Composition> To 250 parts by mass (100 parts by mass as solids) of the copolymer (A) solution obtained above, 1,750 parts by mass of 1-propanol, 600 parts by mass of diacetone alcohol, and 400 parts by mass of 3-methoxy-1-butanol as solvents were added, and 2,000 parts by mass (400 parts by mass as solids) of Snowtex OS (Nissan Chemical Industries, Ltd., acidic sol type, average particle size 9 nm, solids content 20%) as colloidal silica (B) and 1.5 parts by mass of polyether-modified polydimethylsiloxane (trade name: BYK333, BYK-Chemie Japan K.K.) as a leveling agent were mixed to produce an anti-fogging agent composition with a solids content of 10%.

[0062] <Preparation of anti-fogging article> The anti-fog agent composition obtained above was spray-coated onto a 3 mm thick polycarbonate (PC) plate in an atmospheric environment of 25°C and 30% RH so that the thickness of the anti-fog coating film after curing would be approximately 1 μm, and the coating was then heat-cured at 120°C for 20 minutes to produce an anti-fog article (test piece) having an anti-fog coating film. The obtained test piece was evaluated for the following items (1) to (3). The evaluation results are shown in Table 1.

[0063] <(1) Transparency evaluation> In accordance with the test method for total light transmittance of plastic materials (JIS-K7361-1), the haze value of the test piece was measured using a haze meter (HAZE METER HDN5000, manufactured by Nippon Denshoku Industries Co., Ltd.) (light source: white LED, luminous flux: 14 mm, temperature: 25°C, humidity: 50%) and rated on the following four-point scale. A rating of B- or higher indicates no practical problems, B+ is preferable, and A is more preferable. The haze value of a 3 mm thick PC resin plate was 0.30. A: Haze value is 0.30 or more and less than 0.40 B+: Haze value is 0.40 or more and less than 0.50 B-: Haze value is 0.50 or more and less than 0.60 C: Haze value is 0.60 or more

[0064] <(2) Evaluation of Adhesion> The anti-fog coating film of the test piece was cut into a 1 cm long and 1 cm wide area at 1 mm intervals both vertically and horizontally using a utility knife to create 100 grids. Cellophane tape was pressed onto the surface of the grid and then rapidly peeled off, after which the appearance was visually observed and rated on the following three-point scale. A rating of B or higher was acceptable for practical use, and A was preferable. A: No peeling was observed. B: Slight peeling is observed at the intersection of the cuts. C: Partially peeled off or completely peeled off.

[0065] <(3) Evaluation of anti-fogging properties> The test piece was placed with the anti-fog coating side facing downwards at a height of 2 cm above the water surface of a hot water bath maintained at 80°C, and steam from the hot water bath was continuously irradiated onto the anti-fog coating. 10 seconds after irradiation, the presence or absence of fogging was visually evaluated on the following four-point scale. A rating of B- or higher was acceptable for practical use, B+ was preferable, and A was even more preferable. A: A water film is formed immediately after steam irradiation and the glass does not become cloudy. B+: A momentary clouding is observed immediately after steam irradiation, but a water film quickly forms and the clouding does not occur. B-: Clouding is observed immediately after steam irradiation, but a water film forms and the clouding does not occur. C: Clouding was observed immediately after steam irradiation, and no water film was formed.

[0066] <Preparation of anti-fogging article having a thick film> The anti-fog agent composition obtained above was spray-coated onto a 3 mm thick polycarbonate (PC) plate in an atmospheric environment of 25°C and 30% RH so that the thickness of the anti-fog coating film after curing would be approximately 4 to 5 μm, and the coating was then heat-cured at 120°C for 20 minutes to produce an anti-fog article (test piece) having an anti-fog coating film. The obtained test piece was used to perform the following evaluations (4) to (6). The evaluation results are shown in Table 1.

[0067] <(4) Evaluation of the appearance of test pieces after moisture resistance tests for thick films> The test piece was left to stand at 50°C and 95% RH for 240 hours, and then left to stand at room temperature for 1 hour. The appearance of the anti-fog coating film was then visually observed under LED light (luminous flux 380 lumens) and rated on the following four-point scale: A rating of B- or higher is acceptable for practical use, B+ is preferable, and A is more preferable. A: No change from before the test. B+: Slight cracks and whitening are observed. B-: Cracks and whitening are observed. C: Cracks and whitening are evident.

[0068] <(5) Evaluation of anti-fogging properties after humidity resistance test for thick films> The test piece was left to stand at 50°C and 95% RH for 240 hours, and then left to stand at room temperature for 1 hour. The anti-fogging properties of the anti-fogging coating film were then evaluated using the test method (3) and rated on the following three scales. A rating of B or higher is acceptable for practical use, and A is preferable. A: A water film is formed immediately after steam irradiation and the glass does not become cloudy. B: Clouding is observed immediately after steam irradiation, but a water film forms and the clouding does not occur. C: Clouding was observed immediately after steam irradiation, and no water film was formed.

[0069] <(6) Evaluation of repeated condensation resistance when using thick films> The test piece was placed 5 cm above the water surface of a hot water bath maintained at 80°C, with the anti-fog coating side facing downwards. Steam from the hot water bath was irradiated continuously for 10 seconds onto a predetermined 5 cm x 5 cm area of ​​the anti-fog coating, after which the test piece was placed horizontally and left to dry at room temperature. This procedure was repeated 10 times, and the appearance of the test piece after drying was visually evaluated on the following three-point scale. A rating of B or higher was acceptable for practical use, and A was preferable. A: No change from before the test. B: A small amount of adhesion is observed. C: Adhesion is clearly visible.

[0070] <Examples 2 to 16 and Comparative Examples 1 to 7> <Production of anti-fogging agent composition and fabrication of anti-fogging article> Anti-fog agent compositions of Examples 2 to 16 and Comparative Examples 1 to 7 were produced in the same manner as in Example 1, except that the raw materials of Example 1 were changed to the raw materials and their blending amounts shown in Tables 1 to 3. Furthermore, anti-fog articles (test pieces) having the anti-fog coating films of Examples 2 to 16 and Comparative Examples 1 to 7 were produced in the same manner as in Example 1.

[0071] The test pieces obtained above were used in the evaluation methods (1) to (6) above, and the results are shown in Tables 1 to 3.

[0072] [Table 1]

[0073] [Table 2]

[0074] [Table 3]

[0075] In Tables 1 to 3, monomers (A-1) to (A-4) are: GMA is glycidyl methacrylate (R 4 =CH3, R 5 =CH2); GOBA is glycidyloxybutyl acrylate (R 6 =H, R 7 =n-C4H8); DMAA is N,N-dimethylacrylamide (R 1 =H, R 2 =CH3, R 3 =CH3); DEAA is N,N-diethylacrylamide (R 1 =H, R 2 =C2H5,R 3 =C2H5); TBMA, t-butyl methacrylate; CHA is cyclohexyl acrylate; BZMA, benzyl methacrylate; PhEMA, phenoxyethyl methacrylate; N-MAAm, N-methylolacrylamide; HEA, hydroxyethyl acrylate; MMA, methyl methacrylate; St represents styrene;

[0076] In Tables 1 to 3, colloidal silica (B) is Snowtex OS (Nissan Chemical Co., Ltd., acidic sol type, average particle size 9 nm, solid content 20%); Snowtex O is an acidic sol type (manufactured by Nissan Chemical Industries, Ltd., average particle size 12 nm, solid content 20%).

[0077] In Tables 1 to 3, the leveling agents are BYK333 is a polyether-modified polydimethylsiloxane (trade name: "BYK-333", manufactured by BYK Japan Co., Ltd.); KL-100 refers to organically modified silicone (trade name: "Polyflow KL-100", manufactured by Kyoeisha Chemical Co., Ltd.);

[0078] In Table 3, the acid catalyst is DNNDSA represents dinonylnaphthalenedisulfonic acid;

[0079] As shown in Tables 1 and 2, the antifogging agent compositions of Examples 1 to 16 are excellent in transparency, adhesion, and antifogging properties, and can form antifogging coating films, even in thick films, that have excellent appearance after a moisture resistance test, antifogging properties, and resistance to repeated condensation.

[0080] On the other hand, as shown in Table 3, in Comparative Example 1, the copolymer (A) did not contain the monomer (A-1), and therefore the anti-fog coating film dissolved when the anti-fog properties, moisture resistance, and resistance to repeated condensation were evaluated. In Comparative Example 2, the copolymer (A) did not contain the monomer (A-2), and therefore the anti-fog properties were reduced. In Comparative Example 3, the copolymer (A) did not contain the monomer (A-3), and therefore the adhesion of the anti-fog coating film to the substrate was reduced. In Comparative Example 4, the copolymer (A) did not contain the colloidal silica (B), and therefore the anti-fog coating film dissolved when the anti-fog properties, moisture resistance, and resistance to repeated condensation were evaluated.

[0081] Furthermore, Comparative Example 5 is an acrylic copolymer disclosed in an example of Patent Document 1, and does not contain monomer (A-1), so a deterioration in appearance was observed after the moisture resistance test. Comparative Example 6 is an acrylic copolymer disclosed in an example of Patent Document 2, and uses a curing catalyst, so a deterioration in appearance was observed after repeated condensation resistance tests. Comparative Example 7 is an acrylic copolymer disclosed in an example of Patent Document 2, and does not use a curing catalyst, so a deterioration in appearance was observed after the moisture resistance test.

Claims

1. The composition comprises a copolymer (A) and colloidal silica (B), wherein the copolymer (A) is a (meth)acrylate copolymer obtained from a monomer mixture; The monomer mixture comprises a (meth)acrylate monomer (A-1) having an epoxy group, General formula (1): 【Chemistry 1】 (In general formula (1), R １ is a hydrogen atom or a methyl group, and R ２ and R ３ are independently a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms; An antifogging agent composition comprising a hydrophobic (meth)acrylate monomer (A-3) having a hydrocarbon group.

2. 2. The anti-fogging composition according to claim 1, wherein the hydrocarbon group in the monomer (A-3) is at least one functional group selected from the group consisting of a chain hydrocarbon group having a branched structure, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group.

3. 3. The antifogging agent composition according to claim 1, wherein the mass ratio of the monomer (A-1) to the monomer (A-2) [(A-1) / (A-2)] is 0.3 to 3.

0.

4. An anti-fogging article having an anti-fogging coating film formed from the anti-fogging agent composition according to claim 1 or 2.

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