Antifogging agent composition and antifogging article having antifogging film formed from said composition

Abstract

To provide an antifogging agent composition which has excellent antifogging performance and in which traces of water dripping produced when water films are repeatedly formed are hardly whitened even when exposed to a drying condition for a long period of time, and to provide an antifogging article having an antifogging film formed of the composition.SOLUTION: An antifogging agent composition contains a copolymer (A), a polyfunctional blocked isocyanate compound (B), a surfactant (C), and a hydroxy acid compound (D).SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] In vehicle lighting fixtures such as automobile headlamps, high-humidity air can enter the lamp chamber, causing the lens to cool due to factors such as outside air or rain, resulting in condensation of water on the inner surface, causing fogging. As a result, the brightness of the vehicle light is reduced and the aesthetic appearance of the lens surface is impaired, causing discomfort to users. To prevent this type of lens fogging, a known method is to apply an anti-fogging agent to the area where fogging occurs (the inner surface of the lens) to form an anti-fogging film (a dried coating film or a hardened coating film). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 217969 [Patent Document 2] Japanese Patent Publication No. 2020-164842 [Patent Document 3] Japanese Patent Application Publication No. 2018-145243

[0004] Patent Document 1 discloses an anti-fog composition containing a specific copolymer, a polyfunctional blocked isocyanate compound, an anionic surfactant, a surfactant having a quaternary ammonium salt structure, a fluorine-based nonionic surfactant, and colloidal silica. Patent Document 2 discloses an anti-fog composition containing a specific copolymer, a surfactant, and colloidal silica. Patent Document 3 discloses an anti-fog coating composition containing a specific copolymer, a crosslinking agent, a surfactant, and a curing catalyst.

[0005] The anti-fogging film disclosed in Patent Document 1 has excellent anti-fogging performance, is resistant to water drip marks, and any water drip marks that do occur fade over time in a high-humidity environment. The anti-fogging film disclosed in Patent Document 2 above has excellent anti-fogging performance, water resistance, and transparency, and is also excellent at suppressing solvent cracking. Furthermore, the anti-fogging film disclosed in Patent Document 3 above is resistant to water drip marks and changes in appearance even when exposed to high-temperature conditions. Summary of the Invention [Problem to be solved by the invention]

[0006] When moisture comes into contact with the anti-fogging film and the water droplets formed by the formation of a water film dry, the surfactant dissolved in the water precipitates, forming water marks. This water mark formation process is repeated many times, resulting in numerous water marks on the inner surface of the vehicle lamp, resulting in poor appearance.

[0007] The anti-fogging films disclosed in Patent Documents 1 to 3 above have had concerns that water drip marks that occur when water films are repeatedly formed may whiten and become more noticeable if exposed to dry conditions for a long period of time.

[0008] In view of the above circumstances, an object of the present invention is to provide an antifogging agent composition that has excellent antifogging performance and is resistant to whitening of water drip marks that occur when water films are repeatedly formed even when exposed to dry conditions for a long period of time, and an antifogging article having an antifogging film formed from the composition. [Means for solving the problem]

[0009] That is, the present invention relates to an antifogging agent composition comprising a copolymer (A), a polyfunctional blocked isocyanate compound (B), a surfactant (C), and a hydroxy acid compound (D), wherein the copolymer (A) is a (meth)acrylate copolymer obtained from a monomer mixture containing a monomer (A-1) represented by the following general formula (1), a monomer (A-2) represented by the following general formula (2), one or more monomers (A-3) selected from the group consisting of a monomer represented by the following general formula (3) and a monomer represented by the following general formula (4), and one or more monomers (A-4) selected from the group consisting of a monomer represented by the following general formula (5) and a monomer represented by the following general formula (6): [ka] (In general formula (1), R 1 is a hydrogen atom or a methyl group, and R 2 is a linear or branched alkyl group having 1 to 4 carbon atoms, -C(CH3)2CH2COCH3, -C2H4N(CH3)2, or -C3H6N(CH3)2, and R 3 is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. [ka] (In general formula (2), R 4 is a hydrogen atom or a methyl group, and R 5 is a linear, branched, or cyclic hydrocarbon group having 1 to 18 carbon atoms. [ka] (In general formula (3), R 6 is a hydrogen atom or a methyl group, and R 7 is a linear alkylene group having 1 to 4 carbon atoms, and R 8 is a substituent having a heterocyclic skeleton. [ka] (In general formula (4), R 9 is a hydrogen atom or a methyl group, and R 10is a substituent having a heterocyclic skeleton. [ka] (In general formula (5), R 11 is a hydrogen atom or a methyl group, and R 12 is a straight or branched alkylene group having 2 to 4 carbon atoms, or -C2H4(OCO(CH2)5) n -, and n is 1 to 5. [ka] (In general formula (6), R 13 is a hydrogen atom or a methyl group, and R 14 is a linear or branched alkylene group having 1 to 4 carbon atoms.

[0010] The present invention also relates to an anti-fogging article having an anti-fogging film formed from the anti-fogging agent composition on a substrate. [Effects of the Invention]

[0011] The details of the mechanism of action of the antifogging agent composition, antifogging film, and antifogging article of the present invention are presumed to be as follows, although the present invention does not need to be interpreted as being limited to this mechanism of action.

[0012] By blending the surfactant (C) and the hydroxy acid compound (D) with a coating film composed of the copolymer (A) containing the monomer (A-3) and the blocked polyisocyanate compound (B), the heterocyclic substituent of the monomer (A-3) interacts with the hydroxy acid compound (D), and the surfactant (C) interacts with the hydroxy acid compound (D), improving the dispersibility of the surfactant (C) in the coating film and suppressing aggregation. As a result, even when water films are repeatedly formed, the surfactant (C) contained in the resulting water drip marks is less likely to aggregate on the coating film surface, and the water drip marks are less likely to whiten. DETAILED DESCRIPTION OF THE INVENTION

[0013] The antifogging agent composition of the present invention contains a copolymer (A), a polyfunctional blocked isocyanate compound (B), a surfactant (C), and a hydroxy acid compound (D).

[0014] <Copolymer (A)> The copolymer (A) of the present invention is a (meth)acrylate copolymer obtained from a monomer mixture containing at least the following monomers (A-1) to (A-4).

[0015] <Monomer (A-1)> The monomer (A-1) is a monomer represented by the following general formula (1). [ka] (In general formula (1), R 1 is a hydrogen atom or a methyl group, and R 2 is a linear or branched alkyl group having 1 to 4 carbon atoms, -C(CH3)2CH2COCH3, -C2H4N(CH3)2, or -C3H6N(CH3)2, and R 3 is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.

[0016] In the general formula (1), examples of the linear or branched alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, and a t-butyl group. In the general formula (1), from the viewpoint of improving the antifogging performance of the antifogging film and the adhesion to the substrate, R 1 is preferably a hydrogen atom, and R 2 and R 3 are each independently preferably a linear or branched alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

[0017] The monomer (A-1) may be used alone or in combination of two or more.

[0018] <Monomer (A-2)> The monomer (A-2) is a monomer represented by the following general formula (2). [ka] (In general formula (2), R 4 is a hydrogen atom or a methyl group, and R 5 is a linear, branched, or cyclic hydrocarbon group having 1 to 18 carbon atoms.

[0019] In the general formula (2), examples of the linear, branched, or cyclic hydrocarbon group having 1 to 18 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-amyl, i-amyl, t-amyl, n-hexyl, cyclohexyl, n-octyl, 2-ethylhexyl, n-nonyl, isobornyl, lauryl, myristyl, cetyl, and stearyl; alkenyl groups such as oleyl; and aryl groups such as phenyl. From the viewpoints of improving the adhesion and water resistance between the anti-fogging film and the substrate and improving the anti-fogging performance of the anti-fogging film, the branched or cyclic hydrocarbon group having 3 to 16 carbon atoms is preferred, and the branched or cyclic hydrocarbon group having 4 to 12 carbon atoms is more preferred.

[0020] The monomer (A-2) may be used alone or in combination of two or more.

[0021] <Monomer (A-3)> The monomer (A-3) is at least one selected from the group consisting of a monomer represented by the following general formula (3) and a monomer represented by the following general formula (4). [ka] (In general formula (3), R 6 is a hydrogen atom or a methyl group, and R 7 is a linear alkylene group having 1 to 4 carbon atoms, and R 8 is a substituent having a heterocyclic skeleton. [ka] (In general formula (4), R 9 is a hydrogen atom or a methyl group, and R 10 is a substituent having a heterocyclic skeleton.

[0022] In the general formula (3), examples of the linear alkylene group having 1 to 4 carbon atoms include a methylene group, an ethylene group, a propylene group, and a butylene group. Examples of the substituent having a heterocyclic skeleton include an oxygen-containing heterocyclic substituent such as an epoxy group, a 3,4-epoxycyclohexyl group, an oxetanyl group, a furyl group, a tetrahydrofuryl group, an oxotetrahydrofuryl group, a 2-oxo-1,3-dioxolanyl group, a mevalonate lactone group, or a cyclic trimethylolpropane formal group; an oxygen- and nitrogen-containing heterocyclic substituent such as a morpholino group; and a nitrogen-containing heterocyclic substituent such as an N-succinimidyl group, a 1,2,2,6,6-pentamethyl-4-piperidyl group, a 2,2,6,6-tetramethyl-4-piperidyl group, or a 2,2,6,6-tetramethylpiperidine-1-oxyl group. From the viewpoint of suppressing whitening due to dripping water, the substituent having a heterocyclic skeleton is preferably an oxygen-containing heterocyclic substituent.

[0023] In the general formula (4), examples of the substituent having a heterocyclic skeleton include oxygen-containing heterocyclic substituents such as epoxy, 3,4-epoxycyclohexyl, oxetanyl, furyl, tetrahydrofuryl, oxotetrahydrofuryl, 2-oxo-1,3-dioxolanyl, mevalonate lactone, and cyclic trimethylolpropane formal; oxygen- and nitrogen-containing heterocyclic substituents such as morpholino; and nitrogen-containing heterocyclic substituents such as N-succinimidyl, 1,2,2,6,6-pentamethyl-4-piperidyl, 2,2,6,6-tetramethyl-4-piperidyl, and 2,2,6,6-tetramethylpiperidine-1-oxyl. From the viewpoint of suppressing watermark whitening, the substituent having a heterocyclic skeleton is preferably an oxygen-containing heterocyclic substituent.

[0024] As the monomer (A-3), preferably, glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, oxotetrahydrofurfuryl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, morpholinoethyl (meth)acrylate, tetramethylpiperidyl (meth)acrylate, and pentamethylpiperidyl (meth)acrylate can be used, and more preferably, glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, oxotetrahydrofurfuryl (meth)acrylate, and cyclic trimethylolpropane formal (meth)acrylate can be used.

[0025] The monomer (A-3) may be used alone or in combination of two or more.

[0026] <Monomer (A-4)> The monomer (A-4) is at least one selected from the group consisting of a monomer represented by the following general formula (5) and a monomer represented by the following general formula (6). [ka] (In general formula (5), R 11 is a hydrogen atom or a methyl group, and R 12 is a straight or branched alkylene group having 2 to 4 carbon atoms, or -C2H4(OCO(CH2)5) n -, and n is 1 to 5. [ka] (In general formula (6), R 13 is a hydrogen atom or a methyl group, and R 14 is a linear or branched alkylene group having 1 to 4 carbon atoms.

[0027] In the general formula (5), examples of the linear or branched alkylene group having 2 to 4 carbon atoms include an ethylene group, a propylene group, a 2-methylmethylene group, a butylene group, a 2-methylpropylene group, a 3-methylpropylene group, a 2,2-dimethylmethylene group, and a 2-ethylmethylene group. 8 is preferably a linear alkylene group having 2 to 4 carbon atoms, more preferably an ethylene group, a propylene group, or a 2-methylmethylene group, and even more preferably an ethylene group or a propylene group.

[0028] In the general formula (6), examples of the linear or branched alkylene group having 1 to 4 carbon atoms include a methylene group, an ethylene group, a propylene group, a 2-methylmethylene group, a butylene group, a 2-methylpropylene group, a 3-methylpropylene group, a 2,2-dimethylmethylene group, and a 2-ethylmethylene group. 10 is preferably a linear alkylene group having 2 to 4 carbon atoms, more preferably a methylene group, an ethylene group or a propylene group, and even more preferably a methylene group or an ethylene group.

[0029] As the monomer (A-4), preferably, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylamide can be used, and more preferably, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylamide can be used.

[0030] The monomer (A-4) may be used alone or in combination of two or more.

[0031] The hydroxyl value of the copolymer (A) is preferably 5 mgKOH / g or more, more preferably 20 mgKOH / g or more, and even more preferably 40 mgKOH / g or more, from the viewpoint of improving water resistance and reducing water drip marks, and is preferably 160 mgKOH / g or less, more preferably 120 mgKOH / g or less, and even more preferably 90 mgKOH / g or less, from the viewpoint of improving adhesion.

[0032] The proportions of the individual monomer components in the monomer mixture forming the copolymer (A) of the present invention will be described below.

[0033] The amount of the monomer (A-1) is preferably 30 parts by mass or more and 80 parts by mass or less, based on 100 parts by mass of the total of the monomers (A-1), (A-2), (A-3), and (A-4). The amount of the monomer (A-1) is preferably 35 parts by mass or more and more preferably 40 parts by mass or more, based on 100 parts by mass of the total of the monomers (A-1), (A-2), (A-3), and (A-4), from the viewpoint of improving anti-fogging performance, and is preferably 70 parts by mass or less and more preferably 65 parts by mass or less, from the viewpoint of improving water resistance and reducing water drip marks.

[0034] The amount of the monomer (A-2) is preferably 3 parts by mass or more and 30 parts by mass or less, based on 100 parts by mass of the total of the monomers (A-1), (A-2), (A-3), and (A-4). The amount of the monomer (A-2) is preferably 5 parts by mass or more and more preferably 8 parts by mass or more, based on 100 parts by mass of the total of the monomers (A-1), (A-2), (A-3), and (A-4), from the viewpoints of improving water resistance and adhesion and suppressing whitening at water drip marks. The amount of the monomer (A-2) is preferably 25 parts by mass or less and more preferably 20 parts by mass or less, based on 100 parts by mass of the total of the monomers (A-1), (A-2), (A-3), and (A-4), from the viewpoints of improving anti-fogging performance.

[0035] The amount of the monomer (A-3) is preferably 10 parts by mass or more and 50 parts by mass or less, based on 100 parts by mass of the total of the monomers (A-1), (A-2), (A-3), and (A-4). The amount of the monomer (A-3) is preferably 15 parts by mass or more and more preferably 20 parts by mass or more, based on 100 parts by mass of the total of the monomers (A-1), (A-2), (A-3), and (A-4), from the viewpoint of suppressing whitening at water drip marks, and is preferably 45 parts by mass or less and more preferably 40 parts by mass or less, from the viewpoint of improving adhesion.

[0036] The amount of the monomer (A-4) is preferably 5 parts by mass or more and 30 parts by mass or less, based on 100 parts by mass of the total of the monomers (A-1), (A-2), (A-3), and (A-4). The amount of the monomer (A-3) is preferably 8 parts by mass or more and more preferably 10 parts by mass or more, based on 100 parts by mass of the total of the monomers (A-1), (A-2), (A-3), and (A-4), from the viewpoints of improving water resistance and reducing water drip marks, and is preferably 25 parts by mass or less and more preferably 20 parts by mass or less, from the viewpoint of improving adhesion.

[0037] In the monomer mixture, the total proportion of the monomers (A-1) to (A-4) is preferably 85% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0038] The monomer mixture may contain other monomers in addition to the monomers (A-1) to (A-4), such as aromatic vinyl monomers such as styrene, vinyl toluene, and α-methyl styrene; vinyl monomers containing a quaternary ammonium salt structure such as (meth)acryloyloxyethyl trimethyl ammonium chloride and (meth)acryloylaminopropyl trimethyl ammonium chloride; aromatic acrylic monomers such as phenoxyethyl (meth)acrylate; carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, crotonic acid, and maleic acid, and their ammonium salts, organic amine salts, and alkali metal salts; sulfonic acid group-containing vinyl monomers such as styrene sulfonic acid, vinyl sulfonic acid, methallyl sulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, and 3-sulfopropyl (meth)acrylate, and their ammonium salts, organic amine salts, and alkali metal salts; Examples of suitable vinyl monomers include phosphate group-containing vinyl monomers such as (meth)acryloyloxyethyl acid phosphate, and their ammonium salts, organic amine salts, and alkali metal salts; bifunctional (meth)acrylates such as 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol (meth)acrylate, 1,10-decanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, glycerin di(meth)acrylate, and N,N'-methylenebis[(meth)acrylamide]; polyfunctional vinyl monomers such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate; and vinyl monomers having alkoxysilyl groups such as γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropyltriethoxysilane, and vinyltrimethoxysilane.

[0039] <Method for producing copolymer (A)> The copolymer (A) of the present invention can be obtained by copolymerizing the above-mentioned monomer mixture. The copolymer structure may be any of random copolymers, alternating copolymers, block copolymers, and graft copolymers. However, random copolymers are preferred from the viewpoints of improving the effects of the antifogging agent composition, including antifogging properties, and facilitating the preparation of the antifogging agent composition. Various known polymerization methods, such as radical polymerization, cationic polymerization, living radical polymerization, living anionic polymerization, and living cationic polymerization, are used to obtain the copolymer. However, radical polymerization is preferred from the viewpoints of ease of industrial productivity and a wide range of performance aspects. Examples of radical polymerization methods include conventional bulk polymerization, suspension polymerization, solution polymerization, and emulsion polymerization. However, solution polymerization is preferred because the polymerized product can be used as an antifogging agent composition directly.

[0040] Examples of polymerization solvents used in the solution polymerization method include alcohol-based solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, s-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; and water. The polymerization solvents may be used alone or in combination of two or more.

[0041] 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.

[0042] 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 radical polymerization initiator is preferably added dropwise to a reaction vessel while polymerization is being carried out, as this makes it easier to control 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 50 to 100°C, for industrial production.

[0043] The weight-average molecular weight (Mw) of the copolymer (A) is preferably 20,000 or more, more preferably 30,000 or more, from the viewpoint of imparting water resistance to the anti-fogging film, and is preferably 120,000 or less, more preferably 110,000 or less, from the viewpoint of improving the coatability and handleability of the anti-fogging agent composition.

[0044] The weight average molecular weight (Mw) of the copolymer (A) can be determined by a GPC method using a sample prepared by dissolving the sample in tetrahydrofuran to prepare a 0.2% by mass solution and filtering the solution through a 0.5 μm membrane filter under the following conditions: <Measurement of weight average molecular weight (Mw)> Analytical equipment: HLC-8320GPC (Tosoh Corporation) Column: KD-802.5 (Showa Denko), KD-803 (Showa Denko), KD-80M (Showa Denko) connected in series Column size: 8.0 x 300 mm Eluent: tetrahydrofuran Flow rate: 1.0mL / min Detector: differential refractometer Column temperature: 40℃ Standard sample: polystyrene

[0045] <Polyfunctional blocked isocyanate compound (B)> The multifunctional blocked isocyanate compound (B) of the present invention is a compound having two or more isocyanate groups per molecule, in which the isocyanate groups are blocked with a blocking agent. The multifunctional blocked isocyanate compound (B) is not particularly limited as long as it undergoes a crosslinking reaction with the copolymer (A) to form a cured film. At least one type of multifunctional blocked isocyanate compound (B) may be used, or two or more types may be used in combination.

[0046] In the polyfunctional blocked isocyanate compound (B), examples of the compound having two or more isocyanate groups in one molecule include diisocyanate group-containing compounds such as tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, tetramethylxylidene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, trimethylhexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,3-(isocyanatomethyl)cyclohexane, and 1,5-naphthalene diisocyanate; and derivatives of these diisocyanate group-containing compounds such as biuret compounds, isocyanurate compounds, adduct compounds, and allophanate compounds. Among these, from the viewpoint of suppressing yellowing, isophorone diisocyanate, hexamethylene diisocyanate, trimethylhexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,3-(isocyanatomethyl)cyclohexane, and derivatives thereof are preferred.

[0047] Examples of the blocking agent include compounds such as diethyl malonate, 3,5-dimethylpyrazole, ε-caprolactam, phenol, methyl ethyl ketoxime, alcohol, etc. Among these, diethyl malonate is preferred from the viewpoint of good low-temperature curing properties.

[0048] As the polyfunctional blocked isocyanate compound (B), it is preferable to use an isocyanurate or biuret of hexamethylene diisocyanate blocked with diethyl malonate, from the viewpoints of low-temperature curing properties and low yellowing.

[0049] The amount of the polyfunctional blocked isocyanate compound (B) is preferably 5 parts by mass or more and 70 parts by mass or less relative to 100 parts by mass of the copolymer (A). From the viewpoint of improving the water resistance and moisture resistance of the anti-fogging film and reducing the thickness of water drip marks, the amount is preferably 10 parts by mass or more, and more preferably 15 parts by mass or more. From the viewpoint of improving the anti-fogging performance and adhesion of the anti-fogging film and suppressing whitening of water drip marks, the amount is preferably 50 parts by mass or less, and more preferably 30 parts by mass or less.

[0050] The proportions of the copolymer (A) and the polyfunctional blocked isocyanate compound (B) used are preferably such that the equivalent ratio (NCO / OH) of the isocyanate groups of the polyfunctional blocked isocyanate compound (B) to the hydroxyl groups of the copolymer (A) is 0.1 or more and 1.2 or less, and from the viewpoints of improving the water resistance and moisture resistance of the anti-fogging film and reducing the thickness of water drip marks, the ratio is preferably 0.2 or more, and from the viewpoints of improving the anti-fogging performance and adhesion of the anti-fogging film and suppressing whitening of water drip marks, the ratio is preferably 0.8 or less.

[0051] A catalyst may be used to promote the crosslinking reaction. Examples of the catalyst include metal organic compounds such as tin octoate, dibutyltin di(2-ethylhexanoate), dioctyltin di(2-ethylhexanoate), dioctyltin diacetate, dibutyltin dilaurate, and dibutyltin fatty acid salts; and tertiary amines such as tetramethylbutanediamine, 1,4-diazabicyclo[2,2,2]octane, 1,8-diazabicyclo[5,4,0]undecene-7, and 1,5-diazabicyclo[4,3,0]nonene-5.

[0052] <Surfactant (C)> The surfactant (C) of the present invention may be at least one selected from the group consisting of anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants, and may be a combination of two or more types.

[0053] Examples of the anionic surfactant include fatty acid salts such as fatty acid alkali metal salts, such as sodium oleate and potassium oleate; higher alcohol sulfates, such as sodium lauryl sulfate and ammonium lauryl sulfate; alkylbenzenesulfonates and alkylnaphthalenesulfonates, such as sodium dodecylbenzenesulfonate and sodium alkylnaphthalenesulfonate; polyoxyethylene sulfate salts, such as naphthalenesulfonate-formalin condensates, dialkylsulfosuccinates, dialkylphosphate salts, and sodium polyoxyethylene alkylphenyl ether sulfate; and fluorine-containing anionic surfactants, such as perfluoroalkylcarboxylates, perfluoroalkylsulfonates, and perfluoroalkylphosphate esters.

[0054] Examples of the cationic surfactant include amine salts such as ethanolamines, laurylamine acetate, triethanolamine monoformate, and stearamidoethyl diethylamine acetate; and quaternary ammonium salts such as lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, dilauryldimethylammonium chloride, distearyldimethylammonium chloride, lauryldimethylbenzylammonium chloride, stearyldimethylbenzylammonium chloride, tetrabutylammonium bromide, and lauryltrimethylammonium bromide.

[0055] Examples of the amphoteric surfactant include fatty acid-type amphoteric surfactants such as dimethyl alkyl lauryl betaine, dimethyl alkyl stearyl betaine, lauryl dimethyl aminoacetic acid betaine, and lauric acid amidopropyl dimethyl aminoacetic acid betaine; sulfonic acid-type amphoteric surfactants such as dimethyl alkyl sulfobetaine; amine oxide-type amphoteric surfactants such as alkyl (or alkenyl) dimethyl amine oxide, alkyl (or alkenyl) di(hydroxyethyl) amine oxide, polyoxyethylene alkyl (or alkenyl) ether dimethyl amine oxide, and polyoxyethylene alkyl (or alkenyl) ether di(hydroxyethyl) amine oxide; and amino acid-type amphoteric surfactants such as alkyl glycine.

[0056] Examples of the nonionic surfactants include polyoxyethylene higher alcohol ethers such as polyoxyethylene isodecyl ether, polyoxyethylene lauryl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkylaryl ethers such as polyoxyethylene octylphenol and polyoxyethylene nonylphenol; polyoxyethylene acyl esters such as polyoxyethylene monolaurate and polyoxyethylene monostearate; polyoxyethylene sorbitan fatty acid esters such as polypropylene glycol ethylene oxide adduct, polyoxyethylene sorbitan monolaurate, and polyoxyethylene sorbitan monostearate; phosphate esters such as alkyl phosphate esters and polyoxyethylene alkyl ether phosphate esters; sugar esters; and cellulose ethers.

[0057] The surfactant (C) is preferably a combination of an anionic surfactant and a cationic surfactant, or a combination of an anionic surfactant and an amphoteric surfactant, from the viewpoint that good anti-fogging performance can be obtained with a relatively small amount.

[0058] The surfactant (C) is preferably present in an amount of 1 part by mass or more and 12 parts by mass or less relative to 100 parts by mass of the copolymer (A). From the viewpoint of improving the anti-fogging performance of the anti-fogging film, the surfactant (C) is more preferably present in an amount of 2 parts by mass or more and even more preferably present in an amount of 3 parts by mass or more relative to 100 parts by mass of the copolymer (A). From the viewpoint of improving the transparency of the anti-fogging film and suppressing whitening due to dripping water, the surfactant (C) is preferably present in an amount of 10 parts by mass or less and even more preferably present in an amount of 8 parts by mass or less.

[0059] <Hydroxy acid compound (D)> The hydroxy acid compound (D) of the present invention can be any of the conventionally known compounds, including aliphatic hydroxy acids such as glycolic acid, lactic acid, 3-hydroxypropionic acid, glyceric acid, 2-hydroxyisobutyric acid, 2-hydroxy-2,2-dialkylacetic acid, 3-hydroxybutyric acid, 3-hydroxyvaleric acid, 3-hydroxyhexanoic acid, 4-hydroxybutanoic acid, 2-hydroxyisocaproic acid, 1,2-hydroxystearic acid, malic acid, citric acid, and tartaric acid; and aromatic carboxylic acids such as salicylic acid and vanillic acid. From the viewpoint of suppressing watermark whitening, the hydroxy acid compound (D) is preferably glycolic acid, lactic acid, 3-hydroxypropionic acid, or 2-hydroxyisobutyric acid, each of which has a melting point of 80°C or less, and more preferably lactic acid or 3-hydroxypropionic acid, each of which has a melting point of 30°C or less. At least one of the hydroxy acid compounds (D) may be used, or two or more may be used in combination.

[0060] The amount of the hydroxy acid compound (D) is preferably 0.01 to 5 parts by mass relative to 100 parts by mass of the copolymer (A). From the viewpoint of suppressing whitening due to dripping water, the amount of the hydroxy acid compound (D) is more preferably 0.05 to 100 parts by mass, and even more preferably 0.10 to 100 parts by mass of the copolymer (A). From the viewpoint of improving anti-fogging performance, the amount of the hydroxy acid compound (D) is preferably 4 to 100 parts by mass, and even more preferably 3 to 100 parts by mass.

[0061] <Colloidal Silica (E)> The antifogging agent composition of the present invention may contain colloidal silica (E) from the viewpoint of making water drip marks formed during repeated water film formation less likely to whiten when exposed to dry conditions for a long period of time. The colloidal silica (E) is fine silica particles dispersed in a dispersion medium, and known colloidal silicas can be used. From the viewpoint of the transparency of the antifogging film, the colloidal silica (E) preferably has a particle diameter of 100 nm or less, more preferably 50 nm or less, and from the viewpoint of adhesion, preferably 5 nm or more. The particle diameter is represented by the cumulant average particle diameter measured by dynamic light scattering. The colloidal silica (E) may be used alone or in combination of two or more types.

[0062] Examples of the dispersion medium include water; alcohol-based solvents such as methanol, ethanol, isopropanol, n-propanol, isobutanol, and n-butanol; polyhydric alcohol-based solvents such as ethylene glycol; polyhydric alcohol derivatives such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and ethylene glycol monopropyl ether; ketone-based solvents such as methyl ethyl ketone, methyl isobutyl ketone, and diacetone alcohol; amide-based solvents such as dimethylacetamide; ester-based solvents such as ethyl acetate; and aromatic hydrocarbon-based solvents such as toluene.

[0063] The colloidal silica (E) is commercially available, for example, as a water-dispersed colloidal silica sol (trade name: Snowtex O, Snowtex OS, Snowtex O-40, Snowtex OXS, etc.), methanol-dispersed colloidal silica (trade name: Methanol Silica Sol), i-propanol-dispersed colloidal silica (trade name: IPA-ST), ethylene glycol-dispersed colloidal silica (trade name: EG-ST), ethylene glycol mono-n-propyl ether-dispersed colloidal silica (trade name: NPC-ST-30), propylene glycol monomethyl ether-dispersed colloidal silica (trade name: NPC-ST-40), and the like. Examples of suitable colloidal silica include colloidal silica dispersed in ethyl acetate (trade name: PGM-ST), colloidal silica dispersed in dimethylacetamide (trade name: DMAC-ST), colloidal silica dispersed in methyl ethyl ketone (trade name: MEK-ST-40), colloidal silica dispersed in methyl isobutyl ketone (trade name: MIBK-ST), colloidal silica dispersed in ethyl acetate (trade name: EAC-ST), colloidal silica dispersed in propylene glycol monomethyl ether acetate (trade name: PMA-ST), and colloidal silica dispersed in toluene (trade name: TOL-ST) (all manufactured by Nissan Chemical Industries, Ltd.). From the viewpoint of improving anti-fogging performance, the colloidal silica (E) is preferably dispersed in water or a hydrophilic solvent.

[0064] The amount of the colloidal silica (E) is preferably 5 parts by mass or more and 100 parts by mass or less relative to 100 parts by mass of the copolymer (A). From the viewpoint of thinning water drip marks and suppressing whitening, the amount of the colloidal silica (D) is more preferably 10 parts by mass or more relative to 100 parts by mass of the copolymer (A), and from the viewpoint of improving transparency and anti-fogging performance, the amount is preferably 80 parts by mass or less, more preferably 60 parts by mass or less.

[0065] The antifogging agent composition of the present invention may further contain a diluent solvent.

[0066] The dilution solvent is used to adjust the solid content and viscosity of the antifogging agent composition to be suitable for coating. As the dilution solvent, it is preferable to use a polymerization solvent for the copolymer (A). The solid content and viscosity suitable for coating vary depending on the coating method. In the case of a spray coating method, the content of the copolymer (A) in the antifogging agent composition is preferably 3% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 20% by mass or less.

[0067] The antifogging agent composition of the present invention may contain, as other components, various conventional additives such as a leveling agent, a curing catalyst, an antioxidant, an ultraviolet absorber, a light stabilizer, etc. The amount of the other components added may be the conventional amount for each additive, and is usually 10 parts by mass or less per 100 parts by mass of the copolymer (A).

[0068] <Anti-fog articles> The anti-fogging article of the present invention is obtained by applying the anti-fogging agent composition to an object to be coated by a coating method typically used for coating paints, followed by heat curing, thereby forming an anti-fogging film on the surface of the object to be coated.

[0069] Any known resin substrate can be used as the substrate to be coated, regardless of its type, and examples include polymethyl methacrylate resin, polycarbonate resin, polystyrene resin, acrylonitrile-styrene copolymer resin, polyvinyl chloride resin, acetate resin, ABS resin, polyester resin, and polyamide resin.

[0070] When applying the antifogging agent composition to the substrate, it is preferable to remove any foreign matter adhering to the surface of the substrate before application in order to increase the wettability of the antifogging agent composition to the substrate 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 immersion, flow coating, roll coating, bar coating, and spray coating.

[0071] From the viewpoint of obtaining good anti-fogging properties and good coating appearance, the thickness of the anti-fogging film is preferably about 0.5 to 10 μm, and more preferably about 1 to 5 μm.

[0072] The antifogging article is not limited in its application, but can be used, for example, in vehicle lighting fixtures for automobiles, such as headlights, auxiliary headlights, width lights, license plate lights, tail lights, parking lights, back-up lights, turn signals, auxiliary turn signals, and emergency flashers. [Example]

[0073] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0074] <Production of Copolymer (A)> A reaction vessel equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a cooling tube was charged with 150 parts by mass of diacetone alcohol and 150 parts by mass of n-butyl acetate as a polymerization solvent, and heated to 80°C while blowing in nitrogen gas. Next, as the monomer (A-1), 50 parts by mass of N,N-dimethylacrylamide (manufactured by KJ Chemicals, trade name "DMAA"), as the monomer (A-2), 10 parts by mass of isobornyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), as the monomer (A-3), 25 parts by mass of cyclic trimethylolpropane formal acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #200, CTFA"), as the monomer (A-4), 15 parts by mass of 2-hydroxyethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), as the radical polymerization initiator, t-hexyl peroxypivalate (manufactured by NOF Corporation, trade name "Perhexyl PV", active ingredient 70% by mass) 1.0 parts by mass of the solution was added dropwise to the reaction vessel over 2 hours. After the dropwise addition, the mixture was stirred for another hour while maintaining the temperature at 80 ° C., and then cooled to produce a solution of copolymer (A). The polymerization conversion of the charged monomers of copolymer (A) was measured by gas chromatography and found to be 100%. Furthermore, the weight average molecular weight of copolymer (A) was measured by gel permeation chromatography and found to be 80,000. The solid content of the solution of copolymer (A) was 25% by mass. The hydroxyl value (theoretical value) of copolymer (A) was 65 mg KOH / g.

[0075] Example 1 <Production of Antifogging Agent Composition> To 400 parts by mass of the solution containing 100 parts by mass of the copolymer (A) obtained above, 600 parts by mass of propylene glycol monomethyl ether was added to adjust the concentration of the diluted solution of copolymer (A) to 10.0% by mass. Next, 20.0 parts by mass of an isocyanurate of hexamethylene diisocyanate blocked with dialkyl malonate (manufactured by Asahi Kasei Corporation, trade name "Duranate MF-K60B", active ingredient 60% by mass) as the polyfunctional blocked isocyanate compound (B), 4.0 parts by mass of sodium di(2-ethylhexyl)sulfosuccinate (manufactured by NOF Corporation, trade name "Rapisol A80", active ingredient 80% by mass) as the surfactant (C), 0.4 parts by mass of dodecyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd., active ingredient 100% by mass), 1.0 part by mass of DL-lactic acid (manufactured by Kanto Chemical Co., Ltd., active ingredient 90% by mass) as the hydroxy acid compound (D), and 0.05 parts by mass of polyether-modified polydimethylsiloxane (manufactured by BYK-Chemie KK, trade name "BYK-333") as a leveling agent were mixed to produce an antifogging agent composition.

[0076] <Preparation of anti-fogging article> The anti-fog composition obtained above was spray-coated onto a substrate (polycarbonate plate) in an atmospheric environment of 25°C and 30% RH so that the thickness of the coating film after curing would be approximately 2 to 4 μm, and the coating was then heat-cured at 120°C for 20 minutes to produce an anti-fog article (test piece) with an anti-fog film.

[0077] The test pieces obtained above were used to carry out the evaluation methods (1) to (4) below, and the results are shown in Table 1.

[0078] <Evaluation of anti-fogging properties> (1) Steam anti-fogging properties The test piece was placed with the coating surface facing downwards at a height of 2 cm above the water surface in a hot water bath maintained at 80°C, and the coating was continuously irradiated with steam from the hot water bath. The presence or absence of cloudiness after 10 seconds of irradiation was visually evaluated on the following four-point scale. A rating of B or higher is considered satisfactory for practical use. A: No cloudiness is observed. B: Clouding is observed, but the clouding disappears within 10 seconds of steam irradiation. C: 10 seconds after steam irradiation, an uneven water film is observed in part or all of the sample.

[0079] (2) Durable anti-fogging properties The test piece was placed with the coating surface facing downwards at a height of 2 cm above the water surface in a hot water bath maintained at 80°C. Steam from the hot water bath was irradiated onto the coating for 10 seconds continuously, and then the test piece was held upright and the dripping water was allowed to dry at room temperature for 10 to 15 minutes. This process was repeated 30 times, and the resulting water film was evaluated on a three-point scale. A rating of B or higher indicates no practical problems. A: A uniform water film. B: Uneven water film is observed in some areas. C: An uneven water film is observed throughout.

[0080] <(3) Repeated drip marks> The test piece was placed with the coating surface facing downwards at a height of 2 cm above the water surface in a hot water bath maintained at 80°C. Steam from the hot water bath was applied to the coating for 10 seconds continuously, and the test piece was then held upright and the drips were allowed to dry at room temperature for 10 to 15 minutes. This process was repeated 30 times, and the resulting drip marks were left to stand for 30 days in an environment of 20°C and 30% RH. The degree of whitening of the drip marks was visually evaluated on the following four-point scale. A rating of C or higher is acceptable for practical use. A: There is no whitening of the drip marks at all. B: There is almost no whitening of the drip marks. C: The drip marks have turned slightly white. D: The drip marks have turned white overall.

[0081] (4) Adhesion The presence or absence of peeling of the coating film was visually evaluated according to JIS K 5400 8.5.1 using the following three-level rating system: A rating of B or higher indicates no practical problems. A: No peeling was observed. B: Some peeling is observed. C: All peeled off.

[0082] <Examples 2 to 26, Comparative Examples 1 and 2> <Production of anti-fogging agent composition and fabrication of anti-fogging article> In each example and comparative example, antifogging agent compositions of Examples 2 to 26 and Comparative Examples 1 and 2 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 proportions shown in Tables 1 and 2. Furthermore, antifogging articles (test pieces) having antifogging films of Examples 2 to 26 and Comparative Examples 1 and 2 were produced in the same manner as in Example 1.

[0083] Table 1 shows the results obtained by the above evaluation methods (1) to (4) using the test pieces obtained above.

[0084] [Table 1]

[0085] [Table 2]

[0086] In Tables 1 and 2, the monomers (A-1) to (A-4) are: DMAA is N,N-dimethylacrylamide (manufactured by KJ Chemicals, trade name "DMAA"); DEAA is N,N-diethylacrylamide (KJ Chemicals, trade name "DEAA"); CHA is cyclohexyl acrylate (Tokyo Chemical Industry Co., Ltd.); EHMA is 2-ethylhexyl methacrylate (Tokyo Chemical Industry Co., Ltd.); IBOA is isobornyl acrylate (Tokyo Chemical Industry Co., Ltd.); GMA, glycidyl methacrylate (Tokyo Chemical Industry Co., Ltd.); THFMA is tetrahydrofurfuryl methacrylate (Tokyo Chemical Industry Co., Ltd.); CTFA is cyclic trimethylolpropane formal acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #200, CTFA"); FA711MM is pentamethylpiperidyl methacrylate (manufactured by Showa Denko Materials Co., Ltd., trade name "FA-711MM"); HEMA is 2-hydroxyethyl methacrylate (Tokyo Chemical Industry Co., Ltd.); HEAA refers to 2-hydroxyethylacrylamide (manufactured by KJ Chemicals, trade name "HEAA").

[0087] In Tables 1 and 2, the polyfunctional blocked isocyanate compound (B) is Duranate MF-K60B is an isocyanurate of hexamethylene diisocyanate blocked with dialkyl malonate (manufactured by Asahi Kasei Corporation, active ingredient 60% by mass, NCO content 6.5% by mass); Duranate WM44-L70G is an isocyanurate of hexamethylene diisocyanate blocked with dialkyl malonate (manufactured by Asahi Kasei Corporation, active ingredient 70% by mass, NCO amount 5.3% by mass).

[0088] In Tables 1 and 2, surfactant (C) is Rapisol is sodium di(2-ethylhexyl) sulfosuccinate (NOF Corporation, trade name "Rapisol A-80", active ingredient 80% by mass); Pelex TR is sodium ditridecyl sulfosuccinate (Kao Corporation, trade name "Pelex TR," active ingredient 70% by mass); DTAB is dodecyltrimethylammonium bromide (Tokyo Chemical Industry Co., Ltd., active ingredient 100% by mass); TBAB: tetrabutylammonium bromide (Tokyo Chemical Industry Co., Ltd., active ingredient 100% by mass); BL-SF is lauryl dimethylaminoacetic acid betaine (NOF Corporation, trade name "Nissan Anon BL-SF", active ingredient 35.5% by mass); LSB-R is lauramidopropyl hydroxysultaine (manufactured by Kawaken Fine Chemicals Co., Ltd., trade name "Softazoline LSB-R," active ingredient 29% by mass); A-LM indicates lauryl dimethylamine oxide (manufactured by NOF Corporation, trade name "Unisafe A-LM", active ingredient 35% by mass).

[0089] In Tables 1 and 2, the hydroxy acid compound (D) is DL-lactic acid was DL-2-hydroxypropionic acid (Kanto Chemical Co., Ltd., active ingredient 90% by mass); Glycolic acid refers to hydroxyacetic acid (manufactured by Tokyo Chemical Industry Co., Ltd., active ingredient 100% by mass).

[0090] In Tables 1 and 2, colloidal silica (E) is ST-OS is a water-dispersed colloidal silica sol (Nissan Chemical Industries, Ltd., active ingredient 20% by mass, particle size 9 nm); ST-O indicates a water-dispersed colloidal silica sol (manufactured by Nissan Chemical Industries, Ltd., active ingredient 20% by mass, particle size 12 nm).

[0091] In Tables 1 and 2, the leveling agents are BYK333 refers to polyether-modified polydimethylsiloxane (manufactured by BYK-Chemie, active ingredient 100% by mass).

Claims

1. An antifogging agent composition comprising a copolymer (A), a polyfunctional blocked isocyanate compound (B), a surfactant (C), and a hydroxy acid compound (D), The copolymer (A) comprises a monomer (A-1) represented by the following general formula (1), A monomer (A-2) represented by the following general formula (2), one or more monomers (A-3) selected from the group consisting of monomers represented by the following general formula (3) and monomers represented by the following general formula (4), A (meth)acrylate copolymer obtained from a monomer mixture containing one or more monomers (A-4) selected from the group consisting of a monomer represented by the following general formula (5) and a monomer represented by the following general formula (6): The anti-fogging agent composition, wherein the hydroxy acid compound (D) contains lactic acid or glycolic acid. 【Chemistry 1】 (In general formula (1), R １ is a hydrogen atom or a methyl group, and R ２ is a linear or branched alkyl group having 1 to 4 carbon atoms, -C(CH ３ ) ２ CH ２ COCH ３ , -C ２ H ４ N (CH ３ ) ２ , or -C ３ H ６ N (CH ３ ) ２ and R ３ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. 【Chemistry 2】 (In general formula (2), R ４ is a hydrogen atom or a methyl group, and R ５ is a linear, branched, or cyclic hydrocarbon group having 1 to 18 carbon atoms. 【Transformation 3】 (In general formula (3), R ６ is a hydrogen atom or a methyl group, and R ７ is a linear alkylene group having 1 to 4 carbon atoms, and R ８ is a substituent having a heterocyclic skeleton. 【Chemistry 4】 (In general formula (4), R ９ is a hydrogen atom or a methyl group, and R １０ is a substituent having a heterocyclic skeleton. 【Transformation 5】 (In general formula (5), R １１ is a hydrogen atom or a methyl group, and R １２ is a linear or branched alkylene group having 2 to 4 carbon atoms, or -C ２ H ４ (OCO(CH ２ ) ５ ) ｎ - and n is 1 to 5. 【Transformation 6】 (In general formula (6), R １３ is a hydrogen atom or a methyl group, and R １４ is a linear or branched alkylene group having 1 to 4 carbon atoms.

2. 2. The antifogging agent composition according to claim 1, further comprising colloidal silica (E).

3. An anti-fogging article comprising an anti-fogging film formed from the anti-fogging agent composition according to claim 1 or 2 on a substrate.

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