Anti-fogging agent, method for preventing fogging of vehicle lamp structure, and vehicle lamp structure

Abstract

Provided is an anti-fogging agent containing inorganic particles. The inorganic particles include spherical particles and moniliform particles. The content of the spherical particles is 30 mass % or more and less than 50 mass % based on the total content of the spherical particles and moniliform particles.

Description

Anti-fogging agent, method for preventing fogging of vehicle lamp structures, and vehicle lamp structure

[0001] This disclosure relates to an anti-fogging agent, a method for preventing fogging of vehicle lamp structures, and vehicle lamp structures.

[0002] A method is known for applying an anti-fogging agent composition containing a surfactant to the lamp chamber of a vehicle lamp structure, such as an automobile, where fogging due to condensation may occur (see, for example, Patent Document 1). When moisture adheres to the anti-fogging film formed by the anti-fogging agent containing the surfactant, the effect of the surfactant causes the moisture to instantly turn into a water film, suppressing the occurrence of fogging.

[0003] Japanese Patent Publication No. 2016-027134

[0004] However, with the above-mentioned anti-fogging film, when moisture flows off the surface of the anti-fogging film, aggregated surfactants also flow off, which can cause streaks on the surface of the anti-fogging film. In order to form an anti-fogging film that is less prone to such streaks, the inventors investigated anti-fogging agents containing inorganic particles. However, with anti-fogging agents containing inorganic particles, even if appearance defects were suppressed in a single breath anti-fogging test, appearance defects sometimes occurred when the breath anti-fogging test was repeated.

[0005] One aspect of this disclosure, made in view of the above circumstances, aims to provide an anti-fogging agent containing inorganic particles that can form an anti-fogging film that is less prone to appearance defects even when breath anti-fogging tests are repeatedly performed. Another aspect of this disclosure aims to provide a method for preventing fogging of a vehicle lamp structure using the anti-fogging agent, and a vehicle lamp structure using the anti-fogging agent.

[0006] This disclosure includes, for example, the following aspects: [1] An antifogging agent containing inorganic particles, wherein the inorganic particles include spherical particles and bead-like particles, and the content of the spherical particles is 30% by mass or more and less than 50% by mass based on the total content of the spherical particles and the bead-like particles. [2] The antifogging agent according to [1], wherein the inorganic particles are silica particles. [3] The antifogging agent according to [1] or [2], wherein the content of the inorganic particles is 1 to 8% by mass based on the total amount of the antifogging agent. [4] The antifogging agent according to any one of [1] to [3], further comprising a compound obtained by reacting a silane coupling agent having an acid anhydride group or an epoxy group with a sorbitan compound having a hydroxyl group. [5] The antifogging agent according to any one of [1] to [4], further comprising a silane coupling agent having a polyether group. [6] A method for preventing fogging of a vehicle lamp structure, comprising the steps of: applying an anti-fogging agent described in any one of [1] to [5] to the inner surface of a lens provided by the vehicle lamp structure to form a coating film; and drying the coating film. [7] A vehicle lamp structure comprising an anti-fogging film formed from an anti-fogging agent described in any one of [1] to [5] on the inner surface of a lens.

[0007] According to one aspect of this disclosure, it is possible to provide an anti-fogging agent containing inorganic particles that can form an anti-fogging film that is less prone to appearance defects even when breath anti-fogging tests are repeatedly performed. According to another aspect of this disclosure, it is possible to provide a method for preventing fogging of a vehicle lamp structure using the anti-fogging agent, and a vehicle lamp structure using the anti-fogging agent.

[0008] Figure 1 is a schematic representation of a vehicle lamp structure.

[0009] Preferred embodiments of this disclosure will be described in detail below, with reference to the drawings as appropriate. However, this disclosure is not limited to the embodiments described below. Unless otherwise specified, the materials described below may be used individually or in combination of two or more. The content of each component in the composition means the total amount of multiple substances present in the composition, unless otherwise specified, if there are multiple substances corresponding to each component in the composition. Numerical ranges indicated using "~" indicate a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described stepwise in this specification, the upper or lower limit of a numerical range in one step may be replaced with the upper or lower limit of a numerical range in another step. In numerical ranges described in this specification, the upper or lower limit of a numerical range may be replaced with the values ​​shown in the examples.

[0010] <Anti-fogging agent> The anti-fogging agent of this embodiment contains spherical particles and bead-like particles, with the content of spherical particles being 30% by mass or more and less than 50% by mass, based on the total content of spherical particles and bead-like particles. According to the anti-fogging agent of this embodiment, it is possible to form an anti-fogging film that is less prone to appearance defects (e.g., whitening, cracking) even when breath anti-fogging tests are repeatedly performed.

[0011] The inventors speculate that the following is the reason for these effects: When water droplets adhere to the anti-fogging film, the inventors believe that the droplets remain in the voids of the film, causing a defect in appearance. However, by including both spherical and bead-like particles, the particles tend to be arranged more densely in the anti-fogging film, thus reducing the voids within the film. As a result, the size of the water droplets adhering to the anti-fogging film becomes smaller, making them less susceptible to scattering by visible light, and making it difficult to see the water droplets adhering to the film. This makes it possible to form an anti-fogging film that is less prone to defects in appearance even when breath-fogging tests are repeatedly performed. Another possible reason is that the denser arrangement of spherical and bead-like particles improves the overall strength of the anti-fogging film, which also makes it possible to form an anti-fogging film that is less prone to defects in appearance even when breath-fogging tests are repeatedly performed. Furthermore, if there are too few spherical particles, the spherical particles cannot adequately fill the gaps in the skeletal structure formed by the bead-like particles. Conversely, if there are too many spherical particles, the excess spherical particles reduce the proportion of the skeletal structure formed by the bead-like particles. Therefore, it is presumed that an appropriate amount of spherical particles is necessary to prevent defects in appearance.

[0012] (Inorganic Particles) The anti-fogging agent contains inorganic particles, which include spherical particles and bead-like particles. Bead-like particles refer to particles in which multiple spherical particles of approximately the same diameter are linked together. The inorganic particles may also contain particles having shapes (external shapes) other than spherical and bead-like. Examples of shapes (external shapes) other than spherical and bead-like include pearl necklace-like (a shape in which multiple spherical particles of different diameters are linked together), chain-like, scale-like, needle-like, cubic, rectangular parallelepiped-like, cocoon-like, aggregate-like, and konpeito-like shapes.

[0013] Inorganic particles include oxide particles such as silica particles, alumina particles, ceria particles, titania particles, zirconia particles, magnesia particles, yttria particles, zinc oxide particles, iron oxide particles, etc.; nitride particles such as silicon nitride particles, titanium nitride particles, boron nitride particles, etc.; hydroxide particles such as cerium hydroxide particles, etc. From the viewpoint of being able to form an anti-fogging film in which appearance defects are less likely to occur even when the exhalation anti-fogging test is repeatedly performed, the inorganic particles may be silica particles (for example, colloidal silica).

[0014] The silica particles may contain a metal oxide other than silicon dioxide. Examples of the metal oxide include alumina. Examples of such silica particles include colloidal silica in which aluminosilicate is firmly formed on the surface of colloidal silica for the stabilization of the silica sol.

[0015] The silica particles are available as a dispersion of silica particles. Examples of the dispersion medium include water, isopropyl alcohol, 1-methoxy-2-propyl alcohol, ethyl alcohol, methyl alcohol, ethylene glycol, ethylene glycol-n-propyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, dimethylacetamide, N-methylpyrrolidone, toluene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexane, ethyl acetate, etc. The dispersion medium may be a mixed solution of the above dispersion media. From the viewpoint of versatility, the dispersion medium of the silica particles may be water.

[0016] The raw material for silica particles may be water glass or alkoxysilane. When the raw material is water glass, the silica particle production process involves, for example, heating and concentrating sodium silicate using a hydrothermal synthesis method to produce silica particles. Specifically, silica particles may be produced by creating a three-dimensional network structure aggregate under an acidic pH to suppress the growth of primary particles, and then crushing it, or by creating a block-shaped aggregate under an alkaline pH to accelerate the growth of primary particles, and then crushing it. When the raw material is alkoxysilane, the silica particle production process involves, for example, producing silica particles by sol-gel synthesis of alkoxysilane. Specifically, silica particles may be produced by accelerating the hydrolysis reaction of alkoxysilane, then accelerating the polycondensation reaction to obtain a gel, and then removing the solvent by heat treatment, or by obtaining a gel and then performing solvent replacement with a predetermined solvent.

[0017] The dispersion liquid of シリカ particles is commercially available products such as いてよく, example えば, manufactured by Nissan Chemical Co., Ltd. ST-PS-SO, ST-PS- MO、ST-PS-M、ST-PS-S、ST-UP、S T-OUP, IPA-ST-UP, MA-ST-UP, P GM-ST-UP, MEK-ST-UP, IPA-ST, IPA-ST-L, IPA-ST-ZL, MA-ST-M , MA-ST-L, MA-ST-ZL, EG-ST, EG -ST-XL-30, NPC-ST-30, PGM-ST , DMAC-ST, DMAC-ST-ZL, NMP-ST , TOL-ST, MEK-ST-40, MEK-ST-L , MEK-ST-ZL, MIBK-ST, MIBK-ST -L, CHO-ST-M, EAC-ST, PMA-ST, MEK-EC-2130Y, MEK-EC-2430Z, MEK-EC-2140Z, MEK-AC-4130Z, MEK-AC-5140Z, PGM-AC-2140Y, PGM-AC-4130Y, MIBK-AC-2140Z , MIBK-SD-L, ST-XS, ST-OXS, ST -NXS, ST-CXS, ST-S, ST-OS, ST- NS, ST-30, ST-O, ST-N, ST-C, ST-AK, ST-50-T, ST-O-40, ST-N-4 0.ST-CM, ST-30L, ST-OL, ST-AK -L, ST-YL, ST-OYL, ST-AK-YL, S T-ZL, MP-1040, MP-2040, MP-4540M; PL-1-IPA, PL- made by Fuso Chemical Co., Ltd. 1-TOL, PL-2L-PGME, PL-2L-MEK, PL-2L, PL-3, PL-4, PL-5, PL-1H, PL-3H, PL-5H, BS-2L, BS-3L, BS-5L, HL-2L, HL-3L, HL-4L, PL-3-C, PL-3-D; Tama Chemical Industry Co., Ltd.'s TCSOL800; Nichiki Catalyst Chemical Co., Ltd.'s SI-40, SI-50, SI-45P, SI-80P, SIK-23, S-30H, SIK-15, SI-550 etc.

[0018] The average particle size of the inorganic particles may be 1 to 1000 nm. If the average particle size of the inorganic particles is 1 nm or more, the inorganic particles are less likely to aggregate in the anti-fogging agent, making it easier for the inorganic particles to adhere to the substrate. If the average particle size of the inorganic particles is 1000 nm or less, the specific surface area of ​​the inorganic particles increases, making it easier for the inorganic particles to adhere to the substrate. From these viewpoints, the average particle size of the inorganic particles may be 3 to 500 nm, or 5 to 200 nm.

[0019] In this specification, the average particle size of inorganic particles can be measured, for example, by the following procedure: Dilute the inorganic particles with deionized water or any solvent to obtain a diluent so that the inorganic particle content is approximately 1.0% by mass (content at which the transmittance (H) at measurement is 60-70%). Then, measure the average particle size of the inorganic particles in the diluent using dynamic light scattering (manufactured by Otsuka Electronics Co., Ltd., product name: nanoSAQLA).

[0020] The content of spherical particles is 30% by mass or more and less than 50% by mass, based on the total content of spherical and bead-like particles. From the viewpoint of forming an anti-fogging film that is less prone to appearance defects even when breath anti-fogging tests are repeatedly performed, the content of spherical particles may be 48% by mass or less, 45% by mass or less, 42% by mass or less, or 40% by mass or less, based on the total content of spherical and bead-like particles. The content of spherical particles may be 35% by mass or more, or 40% by mass or more, based on the total content of spherical and bead-like particles. From these viewpoints, the content of spherical particles may be 30-48% by mass, 30-45% by mass, 30-42% by mass, or 30-40% by mass, based on the total content of spherical and bead-like particles.

[0021] From the viewpoint of forming an anti-fogging film that is less prone to appearance defects even when breath anti-fogging tests are repeatedly performed, the content of spherical particles may be less than 50% by mass, 48% by mass or less, 45% by mass or less, 42% by mass or less, or 40% by mass or less, based on the total amount of inorganic particles. The content of spherical particles may be 30% by mass or more, 35% by mass or more, or 40% by mass or more, based on the total amount of inorganic particles. From these viewpoints, the content of spherical particles may be 30% by mass or more but less than 50% by mass, 30 to 48% by mass, 30 to 45% by mass, 30 to 42% by mass, or 30 to 40% by mass, based on the total amount of inorganic particles.

[0022] From the viewpoint of forming an anti-fogging film that is less prone to appearance defects even when breath anti-fogging tests are repeatedly performed, the content of bead-like particles may be more than 50% by mass, 52% or more by mass, 55% or more by mass, 58% or more by mass, or 60% or more by mass, based on the total amount of inorganic particles. The content of bead-like particles may be 70% or less by mass, 65% or less by mass, or 60% or less by mass, based on the total amount of inorganic particles. From these viewpoints, the content of bead-like particles may be more than 50% by mass and 70% or less by mass, 52 to 70% by mass, 55 to 70% by mass, 58 to 70% by mass, or 60 to 70% by mass, based on the total amount of inorganic particles.

[0023] From the viewpoint of superior anti-fogging properties, the inorganic particle content may be 1% by mass or more, 5% by mass or more, or 10% by mass or more, based on the total amount of solids in the anti-fogging agent. From the viewpoint of making it easier to maintain anti-fogging properties (hydrophilicity), the inorganic particle content may be 97% by mass or less, 95% by mass or less, 90% by mass or less, 85% by mass or less, or 80% by mass or less, based on the total amount of solids in the anti-fogging agent. From these viewpoints, the inorganic particle content may be 1 to 97% by mass, 5 to 95% by mass, 10 to 90% by mass, 10 to 85% by mass, or 10 to 80% by mass, based on the total amount of solids in the anti-fogging agent.

[0024] From the viewpoint of excellent spray application properties, the inorganic particle content may be 8% by mass or less, 6% by mass or less, 5% by mass or less, 4% by mass or less, or 3% by mass or less, based on the total amount of the antifogging agent (including the liquid medium). The inorganic particle content may be 1% by mass or more, based on the total amount of the antifogging agent. From these viewpoints, the inorganic particle content may be 1 to 8% by mass, 1 to 6% by mass, 1 to 5% by mass, 1 to 4% by mass, or 1 to 3% by mass, based on the total amount of the antifogging agent.

[0025] (Compound product) The anti-fogging agent of this embodiment may further contain a compound E obtained by reacting a silane coupling agent having an acid anhydride group or an epoxy group (hereinafter, this silane coupling agent is also referred to as "silane coupling agent C") with a sorbitan compound having a hydroxyl group (hereinafter, this sorbitan compound is also referred to as "sorbitan compound D"), from the viewpoint of water resistance and moisture resistance.

[0026] [Silane coupling agent C] The silane coupling agent having an acid anhydride group may be, for example, a silane coupling agent represented by general formula (1).

[0027] [In formula (1), R 1１ , R 1２ , and R 13 Each of these independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and a represents an integer from 1 to 10.

[0028] In formula (1), R 1１ , R 1２ , and R 13 Each of these may independently be a hydrogen atom, a methyl group, an ethyl group, a propyl group, or a butyl group. a may be an integer from 1 to 8, 1 to 5, or 1 to 3.

[0029] Examples of silane coupling agents having an acid anhydride group include 3-trimethoxysilylpropyl succinic anhydride (X-12-967C, manufactured by Shin-Etsu Chemical Co., Ltd., etc.).

[0030] The silane coupling agent having an epoxy group may be, for example, a silane coupling agent represented by general formula (2) or general formula (3).

[0031] [In formula (2), R ２１ , R ２２ , and R ２3 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and b represents an integer of 1 to 10. ]

[0032] [In formula (3), R ３１ , R ３２ , and R ３3 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, c represents an integer of 1 to 10, and d represents an integer of 1 to 10. ]

[0033] In formula (2), R 2１ , R 2２ , and R 2３ may each independently be a hydrogen atom, a methyl group, or an ethyl group. b may be an integer of 1 to 8, 1 to 5, or 1 to 3.

[0034] In formula (3), R ３１ , R ３２ , and R ３３ may each independently be a hydrogen atom, a methyl group, or an ethyl group. c may be an integer of 1 to 8, 1 to 5, or 1 to 3. d may be an integer of 1 to 8, 1 to 5, or 1 to 3.

[0035] Examples of the silane coupling agent having an epoxy group include 3-glycidyloxypropyltrimethoxysilane (KBM-403, etc. manufactured by Shin-Etsu Chemical Co., Ltd.), 8-glycidoxyoctyltrimethoxysilane (KBM-4803, etc. manufactured by Shin-Etsu Chemical Co., Ltd.), 3-glycidyloxypropyltriethoxysilane (KBE-403, etc. manufactured by Shin-Etsu Chemical Co., Ltd.), KBE-402, X-12-981S, X-12-984S (all are trade names, manufactured by Shin-Etsu Chemical Co., Ltd.), and the like.

[0036] [Sorbitan compound D] The antifogging agent may contain a sorbitan compound having one or more hydroxy groups (hereinafter also referred to as "sorbitan compound D"). The number of hydroxy groups possessed by the sorbitan compound D may be 2 or more or 3 or more, and may be 4 or less or 3 or less.

[0037] Sorbitan compound D may have polyoxyethylene groups. If sorbitan compound D has polyoxyethylene groups, the number of polyoxyethylene structural units (oxyethylene groups) may be 3 or more, 5 or more, or 6 or more, and may be 30 or less, 25 or less, or 20 or less.

[0038] Sorbitan compound D may also be a sorbitan fatty acid ester compound, which is an ester of sorbitan and a fatty acid. Examples of fatty acids include caprylic acid, capric acid, lauric acid, myristic acid, pentadecyl acid, palmitic acid, margaric acid, stearic acid, oleic acid, vaccenic acid, and linoleic acid.

[0039] If sorbitan compound D is a sorbitan fatty acid ester compound, the number of ester groups in sorbitan compound D may be one or more, three or less, or two or less.

[0040] Sorbitan compound D may be a sorbitan fatty acid ester compound having a polyoxyethylene group. Examples of sorbitan fatty acid ester compounds having a polyoxyethylene group include polyoxyethylene sorbitan monolaurate (such as TW-L120 and TW-L106 manufactured by Kao Corporation) and polyoxyethylene sorbitan monooleate (such as TW-O120 and TW-O106 manufactured by Kao Corporation).

[0041] The structure of compound E is determined according to the structure of the silane coupling agent C and the structure of the sorbitan compound D. Compound E may contain, for example, a compound represented by any of the general formulas (4) to (6). Compound E may contain a condensate of a compound represented by any of the general formulas (4) to (6), or a condensate of a compound represented by any of the general formulas (4) to (6) and the silane coupling agent C.

[0042] [In formula (4), R ４１ , R ４２ , and R ４3 Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R ４４, and R ４５ Each of these independently represents a hydrogen atom or a monovalent organic group, and e represents an integer from 1 to 10.

[0043] [In formula (5), R ５１ , R ５２ , and R ５３ Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R ５４ [where f represents a hydrogen atom or a monovalent organic group, and f represents an integer from 1 to 10.]

[0044] [In formula (6), R ６１ , R ６２ , and R ６３ Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R ６４ [where g represents a hydrogen atom or a monovalent organic group, g represents an integer from 1 to 10, and h represents an integer from 1 to 10.]

[0045] In formula (4), R ４１ , R ４２ , and R ４３ Each of these may independently be a hydrogen atom, a methyl group, or an ethyl group. ４４ and R ４５ Each of these may independently be a hydrogen atom or a structure derived from sorbitan compound D. e may be an integer from 1 to 8, 1 to 5, or 1 to 3.

[0046] In formula (5), R ５１ , R ５２ , and R ５３ Each of these may independently be a hydrogen atom, a methyl group, or an ethyl group. ５４ f may be a hydrogen atom or a structure derived from sorbitan compound D. f may be an integer from 1 to 8, 1 to 5, or 1 to 3.

[0047] In formula (6), R ６１ , R ６２ , and R ６３ Each of these may independently be a hydrogen atom, a methyl group, or an ethyl group. ６４g may be a hydrogen atom or a structure derived from sorbitan compound D. g may be an integer from 1 to 8, 1 to 5, or 1 to 3. h may be an integer from 1 to 8, 1 to 5, or 1 to 3.

[0048] Synthetic product E can be prepared, for example, by stirring a silane coupling agent C and a sorbitan compound D in an environment of 40 to 100°C for 0.5 to 24 hours. The mixing ratio of the silane coupling agent C and the sorbitan compound D may be 10 to 200 parts by mass or 30 to 100 parts by mass of the silane coupling agent C per 100 parts by mass of the sorbitan compound D.

[0049] The conditions for synthesizing compound E can be adjusted, for example, by changing the peak position that can be observed in the IR chart. Specifically, if the silane coupling agent C has an acid anhydride group, the peak of the acid anhydride group, 1780 cm⁻¹, can be observed in the IR chart before synthesis. －１ Nearby peaks, and 1850 cm －１ The progression of the synthesis reaction can be confirmed by the fact that the peak in the vicinity becomes smaller in the IR chart after synthesis. Furthermore, if the silane coupling agent C has an epoxy group, the peak of the epoxy group at 910 cm² will appear in the IR chart before synthesis. －１ The decrease in the peak in the IR chart after synthesis confirms the progress of the synthesis reaction.

[0050] From the viewpoint of providing superior water resistance and moisture resistance of the anti-fogging film, the content of compound E may be 1 part by mass or more, 3 parts by mass or more, 5 parts by mass or more, 8 parts by mass or more, or 10 parts by mass or more per 100 parts by mass of inorganic particles, and may also be 100 parts by mass or less, 80 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, or 20 parts by mass or less. From these viewpoints, the content of compound E may be 1 to 100 parts by mass, 1 to 60 parts by mass, 1 to 40 parts by mass, 1 to 20 parts by mass, 5 to 20 parts by mass, or 10 to 20 parts by mass per 100 parts by mass of inorganic particles.

[0051] From the viewpoint of providing superior water resistance and moisture resistance of the anti-fogging film, the content of synthetic compound E may be 1 part by mass or more, 3 parts by mass or more, 5 parts by mass or more, 8 parts by mass or more, or 10 parts by mass or more, per 100 parts by mass of the total of spherical particles and bead-like particles, or it may be 100 parts by mass or less, 80 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, or 20 parts by mass or less. From these viewpoints, the content of synthetic compound E may be 1 to 100 parts by mass, 1 to 60 parts by mass, 1 to 40 parts by mass, 1 to 20 parts by mass, 5 to 20 parts by mass, or 10 to 20 parts by mass, per 100 parts by mass of the total of spherical particles and bead-like particles.

[0052] From the viewpoint of providing superior water resistance and moisture resistance of the anti-fogging film, the content of synthetic compound E may be 10 parts by mass or more, 30 parts by mass or more, 50 parts by mass or more, or 100 parts by mass or more, or 500 parts by mass or less, 300 parts by mass or less, 200 parts by mass or less, or 150 parts by mass or less, per 100 parts by mass of the silane coupling agent F described later. From these viewpoints, the content of synthetic compound E may be 10 to 500 parts by mass, 30 to 300 parts by mass, 50 to 200 parts by mass, or 100 to 150 parts by mass, per 100 parts by mass of the silane coupling agent F.

[0053] From the viewpoint of providing superior water resistance and moisture resistance of the anti-fogging film, the content of compound E may be 1% by mass or more, 2% by mass or more, 3% by mass or more, or 4% by mass or more, based on the total amount of solids in the anti-fogging agent, and may also be 40% by mass or less, 30% by mass or less, 28% by mass or less, or 26% by mass or less. From these viewpoints, the content of compound E may be 1 to 40% by mass, 2 to 30% by mass, 3 to 28% by mass, or 4 to 26% by mass, based on the total amount of solids in the anti-fogging agent.

[0054] (Silane coupling agent F having a polyether group) The anti-fogging agent of this embodiment may further contain a silane coupling agent F having a polyether group (hereinafter, this silane coupling agent will also be referred to as "silane coupling agent F") from the viewpoint of compatibility.

[0055] The silane coupling agent F may be a compound represented by the following general formula (7).

[0056] [In formula (7), R ７１ , R ７２ , R ７３ and R ７４ Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, L ７１ and L ７２ Each of these independently represents an alkylene group having 1 to 6 carbon atoms, and k represents an integer from 3 to 25.

[0057] R ７１ , R ７２ , R ７３ and R ７４ This may be a methyl group, an ethyl group, a propyl group, or a butyl group. ７１ and L ７２ k may be an ethylene group, a propylene group, or a butylene group. k may be 10 to 20 or 11 to 15.

[0058] Examples of silane coupling agents represented by general formula (7) include A1230 (manufactured by Momentive Performance Materials LLC) and X-12-641 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0059] From the viewpoint of compatibility, the content of the silane coupling agent F may be 1 part by mass or more, 3 parts by mass or more, 5 parts by mass or more, 8 parts by mass or more, or 10 parts by mass or more per 100 parts by mass of inorganic particles, or it may be 100 parts by mass or less, 80 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, or 20 parts by mass or less. From these viewpoints, the content of the silane coupling agent F may be 1 to 100 parts by mass, 1 to 60 parts by mass, 1 to 40 parts by mass, 1 to 20 parts by mass, 5 to 20 parts by mass, or 10 to 20 parts by mass per 100 parts by mass of inorganic particles.

[0060] From the viewpoint of compatibility, the content of the silane coupling agent F may be 1 part by mass or more, 3 parts by mass or more, 5 parts by mass or more, 8 parts by mass or more, or 10 parts by mass or more, per 100 parts by mass of the total of spherical particles and bead-like particles, or 100 parts by mass or less, 80 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, or 20 parts by mass or less. From these viewpoints, the content of the silane coupling agent F may be 1 to 100 parts by mass, 1 to 60 parts by mass, 1 to 40 parts by mass, 1 to 20 parts by mass, 5 to 20 parts by mass, or 10 to 20 parts by mass, per 100 parts by mass of the total of spherical particles and bead-like particles.

[0061] The content of the silane coupling agent F may be 10 parts by mass or more, 30 parts by mass or more, 50 parts by mass or more, or 80 parts by mass or more per 100 parts by mass of the synthetic product E, or it may be 500 parts by mass or less, 400 parts by mass or less, 300 parts by mass or less, or 200 parts by mass or less, from the viewpoint of compatibility.

[0062] The content of the silane coupling agent F may be 1% by mass or more, 3% by mass or more, 5% by mass or more, or 7% by mass or more, based on the total amount of solids in the antifogging agent, and may also be 30% by mass or less, 20% by mass or less, 15% by mass or less, or 13% by mass or less. From these viewpoints, the content of the silane coupling agent F may be 1 to 30% by mass, 3 to 20% by mass, 5 to 15% by mass, or 7 to 13% by mass, based on the total amount of solids in the antifogging agent.

[0063] (Other silane coupling agents) The anti-fogging agent of this embodiment may contain silane coupling agents other than silane coupling agent F. Examples include silane coupling agents having branched or linear alkyl groups of C1 to C30, cycloalkyl groups of C3 to C10, aryl groups of C6 to C10, or fluoro groups.

[0064] Silane coupling agents having branched or linear alkyl groups of C1 to C30 include methyltrimethoxysilane (KBM-13, manufactured by Shin-Etsu Chemical Co., Ltd.), ethyltrimethoxysilane, propyltrimethoxysilane (KBM-3033, manufactured by Shin-Etsu Chemical Co., Ltd.), butyltrimethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane (KBM-3063, manufactured by Shin-Etsu Chemical Co., Ltd.), heptyltrimethoxysilane, octyltrimethoxysilane, nonyltrimethoxysilane, decyltrimethoxysilane (KBM-3103C, manufactured by Shin-Etsu Chemical Co., Ltd.), undecyltrimethoxysilane, dodecyltrimethoxysilane, and tetradecyltrimethoxysilane. Examples include stearyltrimethoxysilane, methyltriethoxysilane (such as KBE-13 manufactured by Shin-Etsu Chemical Co., Ltd.), ethyltriethoxysilane, propyltriethoxysilane (such as KBE-3033 manufactured by Shin-Etsu Chemical Co., Ltd.), butyltriethoxysilane, pentyltriethoxysilane, hexyltriethoxysilane (such as KBE-3063 manufactured by Shin-Etsu Chemical Co., Ltd.), heptyltriethoxysilane, octyltriethoxysilane (such as KBE-3083 manufactured by Shin-Etsu Chemical Co., Ltd.), nonyltriethoxysilane, decyltriethoxysilane, undecyltriethoxysilane, dodecyltriethoxysilane, tetradecyltriethoxysilane, and stearyltriethoxysilane.

[0065] Examples of silane coupling agents having C6 to C10 aryl groups include phenyltrimethoxysilane (KBM-103, KBM-202SS, KBE-103, KBE-202, etc., manufactured by Shin-Etsu Chemical Co., Ltd.) and p-styryltrimethoxysilane (KBM-1403, etc., manufactured by Shin-Etsu Chemical Co., Ltd.).

[0066] Examples of silane coupling agents containing a fluoro group include 3,3,3-trifluoropropyltrimethoxysilane (such as KBM-7103 manufactured by Shin-Etsu Chemical Co., Ltd.).

[0067] (Binder Compound) The antifogging agent of this embodiment may further contain a binder compound. A binder compound is a compound that improves the strength of the antifogging film by bonding with inorganic particles and crosslinking them. Examples of binder compounds include epoxy compounds, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylic acid, acrylic resin, epoxy resin, urethane resin, polyvinylpyrrolidone, polyvinylpyrrolidone vinyl acetate copolymer (vinylpyrrolidone acetate copolymer), polyamine resin, cellulose, dextrin, cellulose nanofiber, silicate oligomer, silicate polymer, etc. Binder compounds can be used individually or in combination of two or more.

[0068] The binder compound may be an epoxy compound, from the viewpoint of providing excellent fogging resistance for the anti-fogging film. Examples of epoxy compounds include polyfunctional epoxy compounds such as ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether.

[0069] Examples of silane oligomers include ethyl silicate 40, ethyl silicate 48, EMS-485, methyl silicate 51, methyl silicate 53A, Colcoat PX, and Colcoat N-103X (all manufactured by Colcoat Co., Ltd.).

[0070] The binder compound content may be 0.1 to 1000 parts by mass, 0.5 to 500 parts by mass, or 1 to 100 parts by mass per 100 parts by mass of inorganic particles, from the viewpoint of providing superior water resistance and moisture resistance of the anti-fogging film.

[0071] The binder compound content may be 0.1 to 30% by mass, 0.3 to 20% by mass, or 0.5 to 10% by mass, based on the total amount of solids in the anti-fogging agent, from the viewpoint of providing superior water resistance and moisture resistance of the anti-fogging film.

[0072] (Metal Catalyst) The antifogging agent of this embodiment may further contain a metal catalyst. The metal catalyst functions as a bonding-promoting material, and the inclusion of a metal catalyst in the antifogging agent makes it easier to form an antifogging film with excellent moisture resistance and water resistance.

[0073] The metal catalyst is not particularly limited and can be selected from known metal catalysts. Examples of metal catalysts include zirconium compounds, titanium compounds, nickel compounds, aluminum compounds, tin compounds, and the like.

[0074] The metal catalyst may be a zirconium compound, an aluminum compound, or a nickel compound, from the viewpoint of providing superior moisture resistance and water resistance of the anti-fogging film. By including at least one selected from the group consisting of zirconium compounds and aluminum compounds as the metal catalyst in the anti-fogging agent, the number of bonding sites with inorganic particles (e.g., silica particles) increases, making it easier to form stronger bonds.

[0075] The metal catalyst may be a commercially available product.

[0076] The anti-fogging agent according to this embodiment may contain additives such as antioxidants, ultraviolet absorbers, and light stabilizers. In addition to acetic acid, the anti-fogging agent may also contain nitric acid, hydrochloric acid, phosphoric acid, p-toluenesulfonic acid, benzenesulfonic acid, methanesulfonic acid, phenolsulfonic acid, oxalic acid, maleic acid, malonic acid, tartaric acid, citric acid, malic acid, acetic acid, lactic acid, succinic acid, benzoic acid, ammonia, urea, imidazole, sodium carbonate, calcium carbonate, sodium acetate, etc., as defoaming agents, catalysts, etc., used when preparing the raw materials. From the viewpoint of adjusting the viscosity of the anti-fogging agent, the anti-fogging agent may contain a thickening agent.

[0077] The anti-fogging agent may be non-surfactant. Non-surfactant means that the amount of surfactants known to be components of anti-fogging agents is 1% by mass or less, based on the total amount of solids in the anti-fogging agent. The anti-fogging agent may not contain surfactants at all (the amount of surfactants may be substantially 0% by mass, based on the total amount of solids in the anti-fogging agent). Examples of surfactants include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants.

[0078] (Liquid medium) The anti-fogging agent may contain a liquid medium. The liquid medium may be a medium that disperses inorganic particles, dissolves compound E, silane coupling agent F, etc. in the anti-fogging agent. The boiling point of the liquid medium may be 185°C or lower, from the viewpoint that the liquid medium will volatilize due to heating during the formation of the anti-fogging film, bringing the inorganic particles closer together and facilitating the formation of bonds between the inorganic particles. The liquid medium may be the same as the dispersion medium contained in the silica particle dispersion, or it may be a different one.

[0079] As a liquid medium, for example, water, organic solvents, or mixed solvents thereof can be used. Examples of organic solvents include alcohols such as methyl alcohol, ethyl alcohol, 1-propanol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, diacetone alcohol, 1-butoxy-2-propanol, 1-hexanol, 1-octanol, 2-octanol, and 3-methoxy-3-methyl-1-butanol; glycols such as polyethylene glycol; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol mono-tert-butyl ether, propylene glycol monomethyl ether acetate, propylene glycol n-propyl ether, and propylene glycol monomethyl ether; ketones such as acetone and methyl ethyl ketone; ethers such as 1,2-dimethoxyethane, tetrahydrofuran, and dioxane; esters such as ethyl acetate and butyl acetate; cyclic hydrocarbons such as cyclohexane; and acetonitrile.

[0080] <Method for preventing fogging of vehicle lamp structures> The anti-fogging agent according to this embodiment can be used to prevent fogging of vehicle lamp structures. The method for preventing fogging of vehicle lamp structures may include, for example, a step of applying the anti-fogging agent to the inner surface of the lens of the vehicle lamp structure to form a coating film (coating step), and a step of drying the coating film (drying step). Prior to the coating step, a cleaning step may be further included for the purpose of removing any release agent adhering to the surface of the lens.

[0081] (Cleaning process) The cleaning solution used in the cleaning process is not particularly limited. If the surface substrate inside the lens of the vehicle lamp structure is polycarbonate, any liquid that does not dissolve the polycarbonate substrate is acceptable, such as water or alcohols. More specifically, it may be water, isopropyl alcohol, methanol, ethanol, etc. The cleaning process may include a step of wiping the substrate with a cloth soaked in the cleaning solution.

[0082] (Coating process) The coating process is, for example, a process of applying an anti-fogging agent to the inner surface of a lens provided in a vehicle lamp structure. The anti-fogging agent may be applied to the entire inner surface of the lens or selectively to a part of it.

[0083] The method of applying the anti-fogging agent is not particularly limited and may include, for example, spin coating, dip coating, spray coating, flow coating, bar coating, gravure coating, etc. The anti-fogging agent may also be applied by impregnating it with cloth or the like. The application method of the anti-fogging agent may be spray coating, from the viewpoint of easily forming a coating film of uniform thickness even on uneven surfaces, and from the viewpoint of high productivity and high utilization efficiency of the anti-fogging agent. These methods can be used individually or in combination of two or more.

[0084] The amount to be applied is not limited as it depends on the components and amount of the anti-fogging agent, but for example, 10 －９ ~10 ３ g / m ２ That's fine.

[0085] The temperature of the antifogging agent used in the coating process may be, for example, 1 to 50°C or 10 to 30°C. A temperature of 1°C or higher makes it easier to further improve antifogging properties and adhesion, while a temperature of 50°C or lower makes it easier to improve the transparency of the antifogging film. The treatment time with the antifogging agent may be, for example, 1 second to 1 hour or 5 to 30 minutes.

[0086] (Drying process) The drying process may involve applying the anti-fog agent and then allowing the liquid medium to volatilize from the anti-fog agent. The liquid medium can be allowed to volatilize by leaving it at room temperature (e.g., 20°C). The adhesion between the inner surface of the lens and the anti-fog film can be further improved by performing the drying process at a higher temperature. The temperature of the drying process can be adjusted according to the heat resistance temperature of the lens, for example, 5 to 300°C or 10 to 200°C. A temperature of 5°C or higher can further improve adhesion, while a temperature of 300°C or lower can further suppress deterioration due to heat. The drying time can be 30 seconds to 150 hours. Through this process, a silica-based anti-fog film is formed on the inner surface of the lens.

[0087] The thickness of the anti-fogging film is not particularly limited, but from the viewpoint of transparency, anti-fogging properties, etc., it may be 100 nm to 1000 μm, 500 nm to 10 μm, or 1000 nm to 5 μm. The film thickness of the anti-fogging film can be measured, for example, by the automatic film thickness measurement system F50 (manufactured by Filmetrics Co., Ltd.).

[0088] Figure 1 is a schematic diagram of a vehicle lamp structure. The inner surface of the lens of the vehicle lamp structure is treated with an anti-fogging agent according to this embodiment. That is, the vehicle lamp structure has an anti-fogging film formed from the anti-fogging agent on the inner surface of the lens. The lamp structure 10 shown in Figure 1 comprises a lamp housing 3 configured as a recessed shape with one end open, and a lens 1 that closes the open side of the lamp housing 3. The material of the lens 1 is, for example, polycarbonate. The lamp housing 3 and the lens 1 form a lamp chamber S. A light source 4 is mounted on the lamp housing 3 and is placed inside the lamp chamber S. An incandescent bulb, LED bulb, halogen bulb, etc., can be appropriately used as the light source 4. Inside the lamp chamber S, as shown in the figure, a reflector 5 that functions as a reflector for the light of the light source 4 may be provided so as to surround the light source 4 from the rear. An anti-fogging film 2 formed from the anti-fogging agent is provided on the inner surface of the lens 1, that is, the surface facing the lamp chamber S. The anti-fog film 2 may be provided on the entire inner surface of the lens 1, or it may be selectively provided on a part of it, as shown in Figure 1.

[0089] <Hydrophilic Agent> The anti-fogging agent of this embodiment can make the substrate surface hydrophilic, and therefore can be called a hydrophilic agent. The hydrophilic surface does not lose much hydrophilicity even after a fogging test, and can form a good water film when moisture adheres to it. As a result, it is possible to suppress the occurrence of fogging on the substrate even in environments where it is exposed to volatile components. The treatment of the substrate can be carried out in the same way as the anti-fogging method described above.

[0090] Examples of materials constituting the base material include resin materials such as polycarbonate, acrylic polymer, polyamide, polyacrylate, polyimide, acrylonitrile-styrene copolymer, styrene-acrylonitrile-butadiene copolymer, polyvinyl chloride, polyethylene, and polycarbonate; metallic materials such as aluminum, magnesium, copper, zinc, iron, titanium, chromium, manganese, cobalt, and nickel; inorganic materials such as silicon dioxide, aluminum oxide, magnesium oxide, copper oxide, zinc oxide, iron oxide, titanium oxide, chromium oxide, manganese oxide, cobalt oxide, and nickel oxide; and glass. Articles equipped with such a base material include the above-mentioned vehicle lamp structures (such as automobile headlights), as well as vehicle windshields, eyeglasses, goggles, mirrors, storage containers, windows, and camera lenses.

[0091] Next, the present disclosure will be further described by the following embodiments, but these embodiments are not intended to limit the present disclosure.

[0092] <Preparation of Silane-Modified Resin> 10 g of Rheodol TW-L120 (manufactured by Kao Corporation) and 6.4 g of a silane coupling agent containing an acid anhydride (manufactured by Shin-Etsu Chemical Co., Ltd., 3-trimethoxysilylpropyl succinic anhydride, trade name: X-12-967C) were mixed, stirred at 60°C for 2 hours, and diluted with 147.7 g of water to obtain a silane-modified resin.

[0093] <Preparation of anti-fogging agent> Snowtex O (spherical silica particles, manufactured by Nissan Chemical Corporation, concentration 20% by mass), Snowtex OUP (bead-shaped silica particles, manufactured by Nissan Chemical Corporation, concentration 15% by mass), acetic acid, a silane coupling agent having a polyether group (manufactured by Momentive, trade name: A1230), a silane-modified resin, water, and IPA were mixed and stirred for 2 hours to obtain the mother liquor.

[0094] A diluted solution was prepared by mixing water, IPA, and ethylene glycol monobutyl ether (EGBE). The mother liquor and diluted solution were prepared so that the amount (mass%) of each component matched the values ​​shown in Tables 1 and 2, thereby obtaining the anti-fogging agents for each example and comparative example. The content of spherical particles in the table is based on the total content of spherical particles and bead-like particles.

[0095] <Formation of anti-fogging film on polycarbonate substrate> A 10 cm square x 2 mm thick polycarbonate substrate was cleaned with isopropyl alcohol. The anti-fogging agent obtained in the example was applied to the substrate using an applicator or spray, and heated at 110°C for 30 minutes to obtain a polycarbonate substrate as a test material.

[0096] <Evaluation> (Exhalation Anti-Fog Performance) In a laboratory with a room temperature of 25°C, exhaled breath was blown onto the anti-fog film of the test material from a distance of 5 cm, and the presence or absence of appearance defects (whitening, cracking) was visually observed. If no appearance defects occurred, it was classified as "A," and if appearance defects occurred, it was classified as "B."

[0097]

[0098]

[0099] 1...Lens, 2...Anti-fog film, 3...Lamp housing, 4...Light source, 5...Reflector, S...Lamp chamber, 10...Lamp structure.

Claims

1. An anti-fogging agent containing inorganic particles, wherein the inorganic particles include spherical particles and bead-like particles, and the content of the spherical particles is 30% by mass or more and less than 50% by mass, based on the total content of the spherical particles and the bead-like particles.

2. The anti-fogging agent according to claim 1, wherein the inorganic particles are silica particles.

3. The antifogging agent according to claim 1, wherein the content of the inorganic particles is 1 to 8% by mass based on the total amount of the antifogging agent.

4. The anti-fogging agent according to claim 1, further comprising a compound obtained by reacting a silane coupling agent having an acid anhydride group or an epoxy group with a sorbitan compound having a hydroxyl group.

5. The anti-fogging agent according to claim 1, further comprising a silane coupling agent having a polyether group.

6. A method for preventing fogging of a vehicle lamp structure, comprising the steps of: applying an anti-fogging agent according to any one of claims 1 to 5 to the inner surface of a lens provided in the vehicle lamp structure to form a coating film; and drying the coating film.

7. A vehicle lamp structure comprising an anti-fog film formed on the inner surface of the lens from an anti-fog agent according to any one of claims 1 to 5.

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