Laminate and method for manufacturing laminate

Abstract

The present invention provides a laminate for forming a water-repellent coating of which the water repellent performance hardly changes over time and which can maintain water repellency longer than coatings in the prior art. A laminate according to the present invention comprises a substrate and a coating layer provided on at least one surface of the substrate. The coating layer includes multiple inorganic oxide composite particles. The inorganic oxide composite particles include first inorganic oxide particles as the cores thereof and include second inorganic oxide particles which have a smaller particle diameter than the first inorganic oxide particles and which are retained on the surfaces of the first inorganic oxide particles. The inorganic oxide composite particles form reliefs in the surface of the coating layer. The porosity of a region A stretching from the surface of the substrate to half the thickness of the coating layer is 33 to 55% in a cross-section in the thickness direction of the laminate.

Description

Laminate and method for manufacturing laminate

[0001] The present invention relates to a laminate and a method for manufacturing the laminate, and more particularly to a laminate having water repellency and a method for manufacturing the laminate.

[0002] Conventionally, water-repellent technology has been widely used for adhesion prevention, mold release, etc. For example, when water droplets adhere to the lens or cover glass of an imaging device, the water droplets cause light refraction, which can degrade the captured image or cause damage, so a water-repellent structure is formed on the surface of the lens or cover glass.

[0003] For example, it is known that a surface having minute irregularities can reduce the contact area with water droplets and therefore exhibit high water repellency. Therefore, various studies have been conducted on such surface structures.

[0004] For example, Patent Document 1 proposes a substrate with a water-repellent coating, which has a water-repellent coating on the surface of a substrate, the water-repellent coating containing inorganic oxide particles, a particle layer in which an adhesive is interposed between the inorganic oxide particles and between the inorganic oxide particles and the substrate, and a water-repellent overcoat layer covering the particle layer, the inorganic oxide particles being sunflower-shaped particles made of base particles made of inorganic oxide and fine particles of inorganic oxide covering the surfaces of the base particles, the surfaces of the sunflower-shaped particles having fine irregularities caused by the fine particles, and further, the upper parts of the inorganic oxide particles have an irregular shape exposed from the adhesive, and the coating surface has an irregular structure covered by the overcoat layer so as to maintain the irregular shape.

[0005] Japanese Patent No. 6713319

[0006] By providing a coating with an uneven structure, the surface of an article becomes water-repellent; however, the coating deteriorates depending on the state of use of the article, the environmental temperature, etc., and the surface unevenness wears away when the article is wiped for cleaning, resulting in a decrease in water-repellent properties over time.

[0007] Therefore, an object of the present invention is to provide a laminate for forming a water-repellent coating whose water-repellent performance is less susceptible to changes over time and which can maintain its water-repellent power for a longer period than conventional laminates.

[0008] After extensive research, the present inventors have noticed that in articles imparted with water repellency by a textured structure, the surface of the article wears away with use, causing the textured shape to disappear, resulting in a decrease in water repellency over time. They have discovered that the above problem can be solved by forming a textured structure on the surface of a substrate using inorganic oxide composite particles containing at least two types of inorganic oxide particles of different sizes, and by forming spaces between the inorganic oxide composite particles in a region A that is half the thickness from the surface of the substrate in the cross section of the thickness direction of the laminate, thereby completing the present invention. By providing a predetermined amount of void space within the film, new textures appear even when the textured surface of the film wears away, allowing good water repellency to be maintained.

[0009] That is, one aspect of the present invention relates to a laminate comprising a substrate and a coating layer provided on at least one surface of the substrate, wherein the coating layer contains a plurality of inorganic oxide composite particles, each of which has a first inorganic oxide particle serving as a core and a second inorganic oxide particle held on the surface of the first inorganic oxide particle and having a particle diameter smaller than that of the first inorganic oxide particle, the inorganic oxide composite particles forming an uneven shape on the surface of the coating layer, and the porosity of a region A of the coating layer that is half the thickness from the surface of the substrate in a cross section in the thickness direction of the laminate is 33 to 55%.

[0010] Another aspect of the present invention relates to a method for producing a laminate, which includes applying a coating liquid containing 30 to 95 vol % in terms of solid content of inorganic oxide composite particles, in which second inorganic oxide particles having a particle size smaller than that of the first inorganic oxide particles are supported on the surfaces of first inorganic oxide particles, to at least one surface of a substrate, and forming a coating layer having on its surface irregularities formed by the inorganic oxide composite particles.

[0011] The laminate of the present invention has excellent water repellency and can maintain the water repellency for a long period of time.

[0012] Fig. 1 is a schematic cross-sectional view of a laminate of the present invention. Fig. 2 shows images of Examples 1, 2, and 7 observed by a scanning electron microscope, where (a) is an image of Example 1, (b) is an image of Example 2, and (c) is an image of Example 7.

[0013] The present invention will be described below, but the present invention is not limited to the examples in the following description. In this specification, the term "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits.

[0014] <Laminate> As shown in Figure 1, the laminate 10 of the present invention includes a substrate 1 and a coating layer 2 provided on at least one surface of the substrate 1. The coating layer 2 contains a plurality of inorganic oxide composite particles 3, and the inorganic oxide composite particles 3 have first inorganic oxide particles 6 that serve as cores, and second inorganic oxide particles 7 that are held on the surfaces of the first inorganic oxide particles 6 and have a particle size smaller than that of the first inorganic oxide particles 6. The coating layer 2 may include a hard coat film 4 that coats the inorganic oxide composite particles 3, and an organic film 5 that coats the inorganic oxide composite particles 3 or the hard coat film 4. In the laminate 10, an uneven shape is formed on the surface of the coating layer 2 by the inorganic oxide composite particles 3, and in a cross section of the laminate 10 in the thickness direction, a region A that is half the thickness of the coating layer 2 from the surface of the substrate 1 has a porosity of 33 to 55%.

[0015] The coating layer 2 is formed by regularly or irregularly arranging a plurality of inorganic oxide composite particles 3, and the inorganic oxide composite particles 3 may or may not overlap in the thickness direction of the laminate. From the viewpoint of suppressing the disappearance of the uneven shape of the surface of the laminate due to abrasion, it is preferable that the surface of the laminate 10 has unevenness of various sizes and shapes, and in order to form such a structure, it is preferable that the inorganic oxide composite particles 3 overlap irregularly in the thickness direction of the laminate 10.

[0016] Furthermore, when the laminate 10 is viewed in a plan view from the coating layer 2 side, it is preferable that the coating layer 2 covers 50% or more of the substrate 1, more preferably 85% or more, and it is most preferable that the entire substrate 1 is covered by the coating layer 2 (i.e., 100%).

[0017] In the laminate 10 of this embodiment, the porosity of region A, which is half the thickness of the coating layer 2 from the surface of the substrate 1, in a cross section in the thickness direction of the laminate 10 is 33 to 55%. If the porosity of region A is 33% or more, an uneven shape appears even when the surface of the laminate 10, i.e., the surface of the coating layer 2, is worn down, so that water repellency can be maintained, and if the porosity is 55% or less, the bond between the substrate 1 and the coating layer 2 is maintained, so that the durability of the laminate 10 can be maintained. The porosity of region A is preferably 34% or more, more preferably 35% or more, and preferably 52% or less, more preferably 50% or less.

[0018] Furthermore, in the laminate 10 of this embodiment, in a cross section in the thickness direction of the coating layer 2, the porosity of region B, which is half the thickness from the surface of the coating layer 2, is preferably 27 to 52%. When the porosity of region B is 27% or more, good water repellency can be exhibited, and when it is 52% or less, good abrasion resistance can be exhibited. The porosity of region B is more preferably 28% or more, even more preferably 30% or more, and more preferably 50% or less, and even more preferably 48% or less.

[0019] In this embodiment, the difference in porosity between region A and region B (region A - region B) is preferably within ±6%. If the difference in porosity between the two regions is within ±6%, the same water repellency as at the beginning of use can be maintained even if the surface of the laminate 10 wears down with use. The difference in porosity between region A and region B (region A - region B) is more preferably within ±5%, and even more preferably within ±4%. Furthermore, from the perspective of maintaining abrasion resistance, the smaller the porosity difference, the better, and there is no particular lower limit. In this embodiment, control of the porosity is related to the durability of the laminate itself and also contributes to water repellency. In other words, porosity is closely related to maintaining excellent durability (abrasion resistance) and water repellency.

[0020] In this specification, the thickness of the coating layer is an average value of film thicknesses determined from arbitrary 10 points measured using image analysis software by photographing the cross section of the laminate with a scanning electron microscope and using the obtained image.

[0021] The porosity can be determined by photographing the cross section of the laminate with a scanning electron microscope, binarizing the obtained image using image analysis software so that void portions and particle portions can be distinguished, and calculating the ratio of the void area to a predetermined area of ​​the coating layer. The porosity of region A is the ratio of the void area to the area of ​​the coating layer at 1 / 2 the height (thickness) of the coating layer on the substrate side, and the porosity of region B is the ratio of the void area to the area of ​​the coating layer at 1 / 2 the height (thickness) of the coating layer on the surface side of the coating layer.

[0022] The laminate preferably has an arithmetic mean roughness (Ra) of 20 to 60 nm and a ten-point mean roughness (Rz) of 200 to 400 nm on the surface on the coating layer side. When the arithmetic mean roughness (Ra) and ten-point mean roughness (Rz) of the laminate surface on the coating layer side are each within the above ranges, excellent water repellency can be exhibited due to the uneven surface shape, while the transparency of the laminate is not reduced. The arithmetic mean roughness (Ra) of the laminate surface on the coating layer side is more preferably 22 nm or more, even more preferably 25 nm or more, and more preferably 55 nm or less, and even more preferably 40 nm or less. The ten-point mean roughness (Rz) of the laminate surface on the coating layer side is more preferably 220 nm or more, even more preferably 240 nm or more, and more preferably 380 nm or less, and even more preferably 300 nm or less.

[0023] The arithmetic mean roughness (Ra) is measured based on the method described in JIS B0601:2001 (ISO4287:1997), and the ten-point mean roughness (Rz) is a value specified in JIS B0601:2001.

[0024] The laminate preferably has a water contact angle of 150° or more on the surface on the coating layer side. A water contact angle of 150° or more can exhibit excellent water repellency, resulting in a laminate that is excellent for practical use. The water contact angle is more preferably 155° or more, and even more preferably 160° or more. Furthermore, since a larger water contact angle is more preferable, the upper limit is not particularly limited, but is preferably 180° or less.

[0025] The water contact angle can be measured using a contact angle meter. A 2 μL water droplet is placed on the surface of the laminate on the coating layer side, or if the water repellency is too high and the water droplet does not adhere to the film surface, it is dropped, and the contact angle of the water droplet is measured at three different points on the surface of the laminate on the coating layer side using the contact angle meter, and the average value is calculated.

[0026] Furthermore, the laminate preferably has a water sliding angle of 15° or less on the surface on the coating layer side. If the water sliding angle is 15° or less, water is less likely to adhere to the laminate surface, resulting in high water repellency and a practically excellent laminate. The water sliding angle is more preferably 10° or less, and the smaller the water sliding angle, the better, so there is no particular lower limit.

[0027] The water sliding angle is measured by placing a 30 μL water droplet on the surface of the coating layer side of the laminate held horizontally, or by dropping it if the water repellency is too high and the droplet does not adhere to the film surface, gradually tilting the laminate and measuring the tilt angle when the water droplet moves 1 mm.This is done at three different points on the surface of the laminate on the coating layer side, and the average value is calculated.

[0028] The haze of the laminate is preferably 0.2 to 5%. If the haze is 5% or less, a laminate with excellent transparency can be obtained. The haze is more preferably 3% or less, and even more preferably 2% or less.

[0029] Haze can be measured using a haze meter (for example, "HM-65L2" manufactured by Murakami Color Research Laboratory) in accordance with JIS K7136:2000 (Method for determining haze of plastic-transparent materials) and JIS Z8722:2009 (Geometric conditions for irradiating and receiving light of transparent objects), or in accordance with JIS K7136:2000 and JIS K7361-1:1997 (Test method for total light transmittance of plastic-transparent materials).

[0030] The total light transmittance of the laminate is preferably 80% or more. A total light transmittance of 80% or more provides excellent transparency and can be suitably applied to various articles. The total light transmittance is more preferably 82% or more, and even more preferably 85% or more. Furthermore, the higher the total light transmittance, the higher the transparency, so there is no particular upper limit. The total light transmittance is measured in accordance with JIS K7361-1:1997.

[0031] The thickness of the laminate is preferably 1 to 5 mm. When the thickness of the laminate is within this range, both water repellency and transparency can be achieved. The thickness of the laminate is more preferably 1.5 mm or more, even more preferably 2 mm or more, and more preferably 4.5 mm or less, even more preferably 4 mm or less.

[0032] Next, each layer constituting the laminate will be described.

[0033] (Substrate) The substrate is a layer that supports the coating layer. The substrate is preferably a plate-shaped substrate. Note that "plate-shaped" includes a soft sheet form. Examples of substrate materials include glass; resins such as polycarbonate, acrylic resin, polyethylene terephthalate (PET), triacetyl cellulose (TAC), polyester resin, and nylon resin; metals such as aluminum and silicon; and ceramics such as silicon nitride, aluminum oxide, and aluminum nitride. Examples of glass include soda-lime glass, alkali-free glass, borosilicate glass, and aluminosilicate glass. Among these, the substrate is preferably either a glass substrate or a metal substrate from the viewpoint of adhesion to inorganic oxide composite particles and, if present, adhesion to functional layers such as hard coat films and organic films.

[0034] The surface of the substrate may have a film having a composition different from that of the substrate, and such a film may be, for example, an anti-reflection film.

[0035] The total light transmittance of the substrate measured in accordance with JIS K7361-1:1997 is preferably 80% or more. A total light transmittance of 80% or more allows the transparency of the laminate to be maintained. The total light transmittance of the substrate is more preferably 82% or more, and even more preferably 85% or more. Furthermore, the higher the total light transmittance, the higher the transparency, so there is no particular upper limit.

[0036] The thickness of the substrate is not particularly limited, but is appropriately selected from the range of 1 to 5 mm.

[0037] (Coating layer) The coating layer contains a plurality of inorganic oxide composite particles. The inorganic oxide composite particles are raspberry-shaped particles having a first inorganic oxide particle as a core and a second inorganic oxide particle having a particle size smaller than that of the first inorganic oxide particle and supported on the surface of the first inorganic oxide particle.

[0038] Examples of inorganic oxides constituting the inorganic oxide particles include SiO ２ , Al ２ O ３ , ZrO ２ , TiO ２ , Fe ２ O ３ , CeO ２ , AgO, CuO, Cu ２ The inorganic oxide particles are preferably particles containing at least one selected from the group consisting of SiO, ZnO, and composite oxides thereof. Among these, from the viewpoints of transparency and refractive index, the inorganic oxide particles are preferably particles containing at least one selected from the group consisting of SiO ２ , Al ２ O ３ , ZrO ２ , TiO ２ More preferably, the material contains at least one selected from the group consisting of SiO ２ is more preferable.

[0039] The inorganic oxide constituting the first inorganic oxide particles and the inorganic oxide constituting the second inorganic oxide particles may be the same or different.

[0040] The shape of the first inorganic oxide particles and the second inorganic oxide particles is not particularly limited, and examples thereof include spherical, elliptical, disk-like, cylindrical, polyhedral, and irregular shapes.

[0041] The first inorganic oxide particles preferably have a particle diameter (diameter of the circumscribed circle) of 30 to 150 nm. When the particle diameter of the first inorganic oxide particles is 30 nm or more, it is easy to form a water-repellent uneven surface, and when it is 150 nm or less, the transparency of the coating layer can be maintained. The particle diameter of the first inorganic oxide particles is more preferably 40 nm or more, even more preferably 50 nm or more, and more preferably 130 nm or less, and even more preferably 100 nm or less.

[0042] The second inorganic oxide particles preferably have a particle diameter (diameter of the circumscribed circle) of 5 to 100 nm. When the particle diameter of the second inorganic oxide particles is 5 nm or more, the specific surface area of ​​the inorganic oxide composite particles increases, resulting in excellent water repellency. When the particle diameter of the second inorganic oxide particles is 100 nm or less, an appropriate uneven shape can be formed on the surface of the first inorganic oxide particles. The particle diameter of the second inorganic oxide particles is more preferably 8 nm or more, even more preferably 10 nm or more, and more preferably 80 nm or less, and even more preferably 50 nm or less.

[0043] In the inorganic oxide composite particles, the particle size of the first inorganic oxide particles is preferably 2 to 5 times the particle size of the second inorganic oxide particles. When the particle size of the first inorganic oxide particles is at least twice the particle size of the second inorganic oxide particles, the second inorganic oxide particles bond to the first inorganic oxide particles to form appropriate composite particles, while when the particle size is 5 times or less, an appropriate uneven shape is formed on the surface of the composite particles, thereby enhancing water repellency. The particle size of the first inorganic oxide particles is more preferably 3 times or more, even more preferably 4 times or more, and more preferably 4.8 times or less, even more preferably 4.5 times or less, of the particle size of the second inorganic oxide particles. Within this range, it is easy to achieve both abrasion resistance and water repellency of the laminate.

[0044] The second inorganic oxide particles are held on the surfaces of the first inorganic oxide particles, and the two may be chemically bonded or physically adsorbed. From the viewpoint of preventing the second inorganic oxide particles from being detached from the first inorganic oxide particles, chemical bonding is preferred. Examples of chemical bonding include covalent bonding, ionic bonding, and intermolecular bonding.

[0045] The second inorganic oxide particles preferably cover 50% or more of the surface of the first inorganic oxide particles. When the coverage of the second inorganic oxide particles is 50% or more, a laminate surface with good water repellency can be formed. Such a coverage is more preferably 55% or more, and even more preferably 60% or more. On the other hand, the coverage is preferably 90% or less, and more preferably 85% or less. Note that this coverage is independent of the porosity.

[0046] The coverage can be determined by observing the surface of the laminate with a scanning electron microscope.

[0047] The particle diameter (diameter of the circumscribed circle) of the inorganic oxide composite particles is preferably 40 to 350 nm. When the particle diameter of the composite particles is 40 nm or more, it is easy to form a space between the inorganic oxide composite particles of 33% or more in region A of the coating layer that is half the thickness from the surface of the substrate. Furthermore, when the particle diameter is 350 nm or less, even if the inorganic oxide composite particles overlap in the thickness direction of the laminate, the thickness of the laminate does not become too thick. The particle diameter of the inorganic oxide composite particles is more preferably 45 nm or more, even more preferably 50 nm or more, and particularly preferably 60 nm or more. Furthermore, it is more preferably 300 nm or less, even more preferably 200 nm or less, particularly preferably 100 nm or less, and most preferably 80 nm or less.

[0048] The particle sizes of the first inorganic oxide particles, the second inorganic oxide particles, and the inorganic oxide particles in the laminate can be measured by dynamic light scattering.

[0049] The coating layer may further include a hard coat film that coats the inorganic oxide composite particles. The hard coat film is a film that increases the surface hardness of the inorganic oxide composite particles to make them less susceptible to scratches and prevents the second inorganic oxide particles from falling off. When a hard coat film is provided to coat the inorganic oxide composite particles, the inorganic oxide composite particles also have excellent abrasion resistance and excellent durability because the water repellency is less susceptible to changes over time.

[0050] The hard coat film preferably contains at least one selected from the group consisting of a polysilazane compound, an alkoxysilane compound, and an isocyanate silane compound.

[0051] Examples of polysilazane compounds include organopolysilazanes such as perhydropolysilazane, polymethylhydrosilazane, poly-N-methylsilazane, poly-N-(triethylsilyl)allylsilazane, poly-N-(dimethylamino)cyclohexylsilazane, and phenylpolysilazane.

[0052] Examples of the alkoxysilane compound include tetraalkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, and tetraisobutoxysilane; bifunctional alkoxysilanes such as dimethyldimethoxysilane, dimethyldiethoxysilane, bis(2-methoxyethoxy)dimethylsilane, diethyldiethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane; methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, and methyltris(2-methoxyethoxy)silane; fluorinated alkyl(trialkoxy)silanes such as hexyltrimethoxysilane, ethyltriethoxysilane, ethyltrippropoxysilane, ethyltributoxysilane, ethyltris(2-methoxyethoxy)silane, hexyltrimethoxysilane, hexyltriethoxysilane, hexyltrippropoxysilane, hexyltributoxysilane, decyltrimethoxysilane, decyltriethoxysilane, decyltrippropoxysilane, decyltributoxysilane, and trifluoropropyltrimethoxysilane; and trifunctional alkoxysilanes such as phenyltrimethoxysilane and phenyltriethoxysilane.

[0053] Examples of the isocyanate silane compound include 3-isocyanate propyl trimethoxysilane, 3-isocyanate propyl triethoxysilane, isocyanate methyl trimethoxysilane, isocyanate methyl triethoxysilane, 3-isocyanate propyl methyl dimethoxysilane, 3-isocyanate propyl methyl diethoxysilane, isocyanate methyl methyl dimethoxysilane, and isocyanate methyl methyl diethoxysilane.

[0054] Among these, from the viewpoint of abrasion resistance, it is preferable that the hard coat film contains a polysilazane compound, and more preferable that it is an inorganic polysilazane such as perhydropolysilazane or an organic polysilazane.

[0055] The thickness of the hard coat film is preferably 1 to 60 nm. When the thickness of the hard coat film is 1 nm or more, the inorganic oxide composite particles can be sufficiently strengthened, and when the thickness is 60 nm or less, the spaces formed between the inorganic oxide composite particles and between the inorganic oxide composite particles and the substrate can be prevented from being blocked. The thickness of the hard coat film is more preferably 5 nm or more, even more preferably 10 nm or more, and more preferably 55 nm or less, even more preferably 50 nm or less.

[0056] Furthermore, it is preferable that the coating layer further comprises an organic film that coats the inorganic oxide composite particles, or the hard coat film when the inorganic oxide composite particles are provided with a hard coat film. The organic film is a layer that imparts a desired function to the coating layer, and examples thereof include a water-repellent film, a water-sliding film, an oil-repellent film, and an anti-fouling film. The organic film may be a single layer or two or more layers. Note that "water repellency" refers to the phenomenon of repelling water, and "water sliding" refers to the phenomenon of water instantly flowing off (sliding off) even when it comes into contact with the film.

[0057] When the organic film is a water-repellent film, the water-repellent film preferably contains at least one selected from the group consisting of fluorine-containing compounds, alkyl group-containing compounds, and silicone-based compounds.

[0058] Examples of fluorine-containing compounds include fluorine-containing silane derivatives such as perfluorooctylethyltrimethoxysilane, perfluorooctylethyltriethoxysilane, perfluorooctylethyltriisopropoxysilane, and trifluoropropyltrimethoxysilane; and fluorine-containing phosphonic acid derivatives such as perfluorohexylphosphonic acid, perfluorooctylphosphonic acid, and perfluorodecylphosphonic acid.

[0059] Examples of the alkyl group-containing compound include phosphonic acid derivatives such as 10-carboxydecylphosphonic acid, 11-hydroxyundecylphosphonic acid, 11-(naphthalen-2-yloxy)undecylphosphonic acid, 11-{2[2-(2-methoxyethoxy)ethoxy]ethoxy}undecylphosphonic acid, octadecylphosphonic acid, and 11-phthalimidondecylphosphonic acid.

[0060] Examples of silicone compounds include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxymethyltrimethoxysilane, γ-glycidoxymethyltriethoxysilane, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-(β-glycidoxyethoxy)propyltrimethoxysilane, γ-(meth)acrylo Oxymethyltrimethoxysilane, γ-(meth)acryloxymethyltriethoxysilane, γ-(meth)acryloxyethyltrimethoxysilane, γ-(meth)acryloxyethyltriethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropyltriethoxysilane, γ-(meth)acryloxypropyltriethoxysilane, butyltrimethoxysilane, isobutyltriethoxysilane, hexyltriethoxysilane butyltriethoxysilane, decyltriethoxysilane, butyltriethoxysilane, isobutyltriethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltriethoxysilane, 3-ureidoisopropylpropyltriethoxysilane, perfluorooctylethyltrimethoxysilane, perfluorooctylethyltriethoxysilane, perfluorooctylethyltriisopropoxysilane, trifluoropropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane,Examples of such silane include N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, trimethylsilanol, methyltrichlorosilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, trimethylsilanol, methyltrichlorosilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldimethoxysilane.

[0061] Among these, from the viewpoint of achieving high water-repellent properties, the water-repellent film preferably contains a fluorine-containing compound, and more preferably contains a structure with four or more consecutive fluoroalkyl chains.

[0062] When the organic film is a synovial film, the synovial film preferably contains a silicone-based compound, and specific examples thereof include the silicone-based compounds described above.

[0063] When the organic film is an oil-repellent film, the oil-repellent film preferably contains a fluorine-based compound, and specific examples thereof include the above-mentioned fluorine-based compounds.

[0064] When the organic film is an anti-fouling film, the anti-fouling film preferably contains a silicone-based compound, and specific examples thereof include the silicone-based compounds described above.

[0065] The thickness of the organic film is preferably 1 to 10 nm in terms of layer thickness. When the thickness of the organic film is 1 nm or more, the desired effect of providing the organic film can be sufficiently obtained, and when the thickness is 10 nm or less, the spaces formed between the inorganic oxide composite particles and between the inorganic oxide composite particles and the substrate can be prevented from being blocked.

[0066] The thickness (film thickness) of the coating layer is preferably 100 to 3000 nm. When the thickness of the coating layer is 100 nm or more, the irregularities formed by the inorganic oxide composite particles are of an appropriate size, thereby exhibiting excellent water repellency, and when the thickness is 3000 nm or less, the shape of the article is not damaged when the laminate is applied to the surface of the article. The thickness of the coating layer is more preferably 145 nm or more, even more preferably 150 nm or more, and more preferably 1000 nm or less, even more preferably 600 nm or less, particularly preferably 350 nm or less, and most preferably 200 nm or less.

[0067] The thickness of the coating layer is the average value of film thicknesses determined from arbitrary 10 points measured using image analysis software by photographing the cross section of the laminate using a scanning electron microscope as described above.

[0068] <Method for producing laminate> The laminate of the present invention is produced by applying a coating liquid containing 30 to 95 vol % in terms of solid content of inorganic oxide composite particles in which second inorganic oxide particles having a particle size smaller than that of the first inorganic oxide particles are supported on the surfaces of first inorganic oxide particles, to at least one surface of a substrate, to form a coating layer having on its surface irregularities formed by the inorganic oxide composite particles.

[0069] (Preparation of inorganic oxide composite particles) The inorganic oxide composite particles may be obtained by manufacturing, or commercially available inorganic oxide composite particles may be used if they are commercially available. A method for manufacturing inorganic oxide composite particles will be described below.

[0070] Examples of methods for producing inorganic oxide composite particles include a method in which the first inorganic oxide particles and the second inorganic oxide particles are chemically bonded on the surfaces of the particles, a method in which the first inorganic oxide particles and the second inorganic oxide particles are adsorbed by physical adsorption, etc. From the viewpoint of preventing the second inorganic oxide particles from being detached from the first inorganic oxide particles, the method in which the first inorganic oxide particles are chemically bonded is preferred.

[0071] In the method of bonding by chemical bonding, groups that form chemical bonds are introduced onto the surfaces of the first inorganic oxide particles and the second inorganic oxide particles, and these groups are chemically bonded to form a composite of the two.

[0072] Examples of groups that form chemical bonds include groups that can form covalent bonds, groups that can form ionic bonds, groups that can form hydrogen bonds, and groups that can form dipole-dipole interactions. From the viewpoint of the strength of the bonded portions in the inorganic oxide composite particles, groups that can form covalent bonds are preferred.

[0073] The covalently bondable group is not particularly limited as long as it is a group capable of forming a covalent bond, and examples thereof include epoxy groups, oxetanyl groups, isocyanate groups, acid anhydride groups, carbodiimide groups, N-hydroxyester groups, glyoxal groups, imide ester groups, halogenated alkyl groups, thiol groups, hydroxy groups, carboxy groups, amino groups, amide groups, aldehyde groups, and sulfonic acid groups. Among these, from the viewpoint of ease of synthesis, at least one functional group selected from the group consisting of epoxy groups, amino groups, isocyanate groups, and mercapto groups is preferred. When one of the covalently bondable groups is, for example, an epoxy group, examples of the group capable of covalently bonding with the epoxy group include amino groups, hydroxy groups, and carboxy groups. Furthermore, when one of the covalently bondable groups is, for example, an amino group, examples of the group capable of covalently bonding with the amino group include epoxy groups and isocyanate groups. Among these, from the viewpoint of ease of availability, it is preferable that one of the covalently bondable groups is an epoxy group, and it is more preferable that the epoxy group and the amino group are covalently bonded.

[0074] A method for introducing groups that form chemical bonds into inorganic oxide particles includes treating the surfaces of the inorganic oxide particles with a compound having groups that form chemical bonds. For example, when introducing epoxy groups or amino groups into the surfaces of inorganic oxide particles, a silane coupling agent is preferably used.

[0075] Examples of silane coupling agents containing an epoxy group include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane. These may be used alone or in combination of two or more.

[0076] Examples of silane coupling agents containing an amino group include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, etc. These may be used alone or in combination of two or more.

[0077] An example of a silane coupling agent containing an isocyanate group is 3-isocyanatepropyltriethoxysilane.

[0078] Examples of silane coupling agents containing a mercapto group include 3-mercaptopropyltrimethoxysilane and 3-mercaptopropylmethyldimethoxysilane.

[0079] Hereinafter, a method for combining first inorganic oxide particles and second inorganic oxide particles by covalently bonding epoxy groups and amino groups will be described as an example. First, the first inorganic oxide particles are treated with a silane coupling agent containing epoxy groups to obtain epoxy-modified inorganic oxide particles with epoxy groups introduced onto the particle surface. Similarly, the second inorganic oxide particles are treated with a silane coupling agent containing amino groups to obtain amino-modified inorganic oxide particles with amino groups introduced onto the particle surface. Note that the introduction of epoxy groups and amino groups may be reversed.

[0080] The surface modification of the inorganic oxide particles with a silane coupling agent may be carried out according to a known method.

[0081] In the surface treatment with a silane coupling agent, the amount of silane coupling agent used is preferably 1 to 100 parts by mass per 100 parts by mass of inorganic oxide particles. When the amount of silane coupling agent used per 100 parts by mass of inorganic oxide particles is 1 part by mass or more, sufficient functional groups can be introduced onto the inorganic oxide particle surface, and when the amount is 100 parts by mass or less, excessive use of the silane coupling agent can be suppressed. The amount of silane coupling agent used per 100 parts by mass of inorganic oxide particles is more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and more preferably 95 parts by mass or less, even more preferably 90 parts by mass or less.

[0082] The treatment temperature in the surface treatment is preferably 15 to 60°C. When the treatment temperature is 15°C or higher, the reaction occurs quickly and workability is good, and when the treatment temperature is 60°C or lower, side reactions such as thermal decomposition can be suppressed. The treatment temperature is more preferably 20°C or higher, even more preferably 25°C or higher, and more preferably 55°C or lower, even more preferably 50°C or lower.

[0083] The treatment time for the surface treatment is preferably 10 minutes to 12 hours. If the treatment time is 10 minutes or more, the reaction proceeds sufficiently and sufficient functional groups can be introduced onto the surface of the inorganic oxide particles, while if the treatment time is 12 hours or less, the working efficiency can be improved. The treatment temperature is more preferably 20 minutes or more, and even more preferably 30 minutes or more, and more preferably 10 hours or less, and even more preferably 6 hours or less.

[0084] The surface treatment of inorganic oxide particles with a silane coupling agent is preferably carried out in a liquid in order to uniformly introduce functional groups onto the surfaces of the inorganic oxide particles. For example, a reaction is carried out by mixing a dispersion of inorganic oxide particles with a solution containing a silane coupling agent. The reaction is preferably carried out under stirring, and the mixture is preferably stirred at a speed of, for example, 30 to 300 rpm, so as not to stir the mixture vigorously.

[0085] First inorganic oxide particles having epoxy groups introduced therein (epoxy-modified inorganic oxide particles) and second inorganic oxide particles having amino groups introduced therein (amino-modified inorganic oxide particles) are mixed and reacted, whereby the functional groups react with each other, and the second inorganic oxide particles are covalently bonded to the surfaces of the first inorganic oxide particles. Specifically, the reaction is carried out by mixing a dispersion in which the epoxy-modified inorganic oxide particles are dispersed with a dispersion in which the amino-modified inorganic oxide particles are dispersed.

[0086] The amounts of the dispersion liquid in which the epoxy-modified inorganic oxide particles are dispersed and the dispersion liquid in which the amino-modified inorganic oxide particles are dispersed are preferably in the range of 50 to 300 parts by mass of the second inorganic oxide particles per 100 parts by mass of the first inorganic oxide particles. When the amount of the second inorganic oxide particles used per 100 parts by mass of the first inorganic oxide particles is 50 parts by mass or more, the surfaces of the first inorganic oxide particles can be covered with the second inorganic oxide particles, and when the amount is 300 parts by mass or less, excess residue of the second inorganic oxide particles not used in the reaction can be suppressed. The amount of the second inorganic oxide particles used per 100 parts by mass of the first inorganic oxide particles is more preferably 80 parts by mass or more, even more preferably 120 parts by mass or more, and more preferably 240 parts by mass or less, even more preferably 160 parts by mass or less.

[0087] During the reaction, it is preferable to treat with ultrasound to uniformly disperse the epoxy-modified inorganic oxide particles and the amino-modified inorganic oxide particles and to facilitate the reaction. The ultrasound treatment is preferably carried out at a frequency in the range of 30 to 60 kHz for 10 to 120 minutes.

[0088] As a result, a dispersion liquid in which inorganic oxide composite particles are dispersed is obtained.

[0089] (Formation of Coating Layer) In the method for producing a laminate of the present invention, a coating liquid containing 30 to 95 vol% of the inorganic oxide composite particles obtained as described above in terms of solid content is prepared, and the coating liquid is applied to a substrate to form a coating layer having a surface texture formed by the inorganic oxide composite particles. By using a coating liquid containing 30 to 95 vol% of the inorganic oxide composite particles in terms of solid content, a film with appropriate viscosity and solid content can be produced, resulting in the formation of a space in region A of the coating layer, which is half the thickness from the surface of the substrate. The content of the inorganic oxide composite particles in the coating liquid is preferably 35 vol% or more, more preferably 40 vol% or more, and more preferably 90 vol% or less, and even more preferably 85 vol% or less, in terms of solid content.

[0090] Examples of solvents for dispersing the inorganic oxide composite particles include lower alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, and n-butanol, and mixed alcohol solvents thereof; ketones such as methyl ethyl ketone; and dimethylformamide.

[0091] The coating liquid contains a matrix that acts as an adhesive between the inorganic oxide composite particles and between the inorganic oxide composite particles and the substrate. The matrix contains at least one selected from the group consisting of tetraethoxysilane (TEOS), methyltriethoxysilane, a bissilane compound, and a silazane compound, and preferably contains at least one selected from the group consisting of tetraethoxysilane (TEOS), methyltriethoxysilane, and a bissilane compound. An example of the bissilane compound is 1,2-bis(triethoxysilyl)ethane.

[0092] The coating solution preferably contains 15 to 50 parts by mass of matrix per 100 parts by mass of inorganic oxide composite particles. When the matrix content per 100 parts by mass of inorganic oxide composite particles is 15 parts by mass or more, adhesion between the inorganic oxide composite particles and the substrate is sufficiently promoted, allowing a coating layer containing inorganic oxide composite particles to be formed on the substrate. When the matrix content per 100 parts by mass of inorganic oxide composite particles is 50 parts by mass or less, voids of 33% or more are formed in region A of the coating layer that is half the thickness from the surface of the substrate, making it easier to achieve the effects of the present invention. The matrix content per 100 parts by mass of inorganic oxide composite particles is more preferably 20 parts by mass or more, even more preferably 25 parts by mass or more, and more preferably 45 parts by mass or less, and even more preferably 40 parts by mass or less.

[0093] The matrix may be added directly to the dispersion liquid in which the inorganic oxide composite particles are dispersed, or a solution in which the matrix is ​​dissolved or dispersed may be prepared and mixed with the dispersion liquid in which the inorganic oxide composite particles are dispersed. Examples of the solvent in which the matrix is ​​dissolved or dispersed include the above-mentioned lower alcohols and mixed alcohol solvents.

[0094] The coating method of the coating liquid can be a known method, such as spin coating, dip coating, flow coating, bar coating, roll coating, etc. Among these, from the viewpoint of forming a thin film without damaging the unevenness of the coating layer surface, spin coating, dip coating, and flow coating are preferred, and spin coating is more preferred.

[0095] When forming a coating layer on a substrate by spin coating, the spin coating conditions are, for example, to set the substrate on a spin coater, and spin coat the coating liquid at 500 to 3000 rpm for 10 to 60 seconds, so that the coating liquid is uniformly applied to a desired thickness after drying.

[0096] Next, the coating solution is heated at 50 to 550° C., preferably 250 to 550° C., for 10 to 60 minutes, preferably 20 to 40 minutes, to evaporate excess organic solvent contained in the coating solution.

[0097] As a result, the inorganic oxide composite particles form an uneven shape on the surface of the coating layer, and the inorganic oxide composite particles and the inorganic oxide composite particles and the substrate are bonded to each other, and spaces are partially formed between them.

[0098] When the covering layer has a hard coat film, it is preferable to spin coat a coating liquid for forming the hard coat film before the heating.

[0099] The content of the active ingredient in the coating solution for forming a hard coat film is preferably 0.1 to 10% by mass. When the content of the active ingredient in the coating solution is 0.1% by mass or more, the desired effect of the active ingredient can be obtained, and when it is 10% by mass or less, the reaction of the active ingredient in the atmosphere can be suppressed. The content of the active ingredient in the coating solution is more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and more preferably 8% by mass or less, and even more preferably 5% by mass or less.

[0100] Examples of solvents that can dissolve or disperse the active ingredient include hexane, xylene, mineral turpentine, and dibutyl ether.

[0101] The conditions for spin-coating the coating liquid for forming a hard coat film are as follows: the substrate on which a layer made of inorganic oxide composite particles has been formed is set in a spin coater, and the coating liquid is spin-coated at 300 to 3000 rpm for 10 to 60 seconds, so that the coating liquid is uniformly applied so that the film thickness of the hard coat film after drying will be the desired thickness.

[0102] Thereafter, the substrate is heated under the above-mentioned conditions to evaporate excess organic solvent contained in the coating liquid and the coating liquid for forming the hard coat film.

[0103] Thereafter, if necessary, the inorganic oxide composite particles formed on the substrate, or if the inorganic oxide composite particles are covered with a hard coat film, the hard coat film, is coated with an organic film. When coating with an organic film, it is preferable to subject the inorganic oxide composite particles or the hard coat film to a plasma treatment to make the surface clean.

[0104] The content of the active ingredient in the coating liquid for forming an organic film is preferably 1 to 10% by mass. When the content of the active ingredient in the coating liquid is 1% by mass or more, the desired effect of the active ingredient can be obtained, and when it is 10% by mass or less, reactions between the active ingredients can be suppressed. The content of the active ingredient in the coating liquid is more preferably 2% by mass or more, even more preferably 3% by mass or more, and more preferably 8% by mass or less, and even more preferably 6% by mass or less.

[0105] Examples of solvents for dissolving or dispersing the active ingredient include lower alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, and n-butanol, and mixed alcohol solvents thereof.

[0106] The conditions for spin-coating the coating liquid for forming an organic film are as follows: a substrate on which a layer of inorganic oxide composite particles has been formed is set in a spin coater, and the coating liquid is spin-coated at 300 to 3,000 rpm for 10 to 60 seconds, and the coating liquid is applied uniformly so that the organic film has a desired thickness after drying. The organic film may be a single layer, or multiple layers may be formed using different active ingredients.

[0107] Thereafter, the laminate of the present invention is obtained by heating for 0.5 to 30 hours, preferably 1 to 24 hours, in an environment at a temperature of 20 to 60°C, preferably 30 to 50°C, and a humidity of 20 to 95% RH, preferably 40 to 80% RH. Heating may be carried out in one step, or may be carried out in multiple steps under conditions of different treatment temperatures, treatment humidity, or treatment times.

[0108] <Applications> The laminate of the present invention has excellent water repellency and can provide articles with a non-adhesive surface to which undesirable deposits do not adhere, or which can be easily removed even if they do adhere, in many fields such as electronic devices, automobiles, medical devices, fuel transportation, construction, food containers, solar cells, etc. The laminate is particularly useful for eyeglass lenses, smartphones, wearable devices, car navigation systems, housings for electronic devices, camera covers, sensor covers, etc.

[0109] As described above, the present specification discloses the following configurations: (1) A laminate comprising a substrate and a coating layer provided on at least one surface of the substrate, wherein the coating layer contains a plurality of inorganic oxide composite particles, each of which has a first inorganic oxide particle serving as a core and a second inorganic oxide particle held on the surface of the first inorganic oxide particle and having a particle size smaller than that of the first inorganic oxide particle, wherein the inorganic oxide composite particles form an irregular shape on the surface of the coating layer, and wherein a porosity of a region A of the coating layer that is half the thickness from the surface of the substrate in a cross section in the thickness direction of the laminate is 33 to 55%. (2) A laminate wherein the inorganic oxide composite particles are SiO ２ , Al ２ O ３ , ZrO ２ , TiO ２ , Fe ２ O ３ , CeO ２ , AgO, CuO, Cu ２The laminate according to (1), comprising at least one particle selected from the group consisting of O, ZnO, and composite oxides thereof. (3) The laminate according to (1) or (2), wherein the particle diameter of the first inorganic oxide particles is 2 to 5 times the particle diameter of the second inorganic oxide particles. (4) The laminate according to any one of (1) to (3), wherein the particle diameter of the first inorganic oxide particles is 30 to 150 nm. (5) The laminate according to any one of (1) to (4), wherein the particle diameter of the inorganic oxide composite particles is 40 to 350 nm. (6) The laminate according to any one of (1) to (5), wherein the coating layer further comprises a hard coat film coating the inorganic oxide composite particles. (7) The laminate according to (6), wherein the hard coat film comprises at least one selected from the group consisting of a polysilazane compound, an alkoxysilane compound, and an isocyanate silane compound. (8) The laminate according to (6) or (7), wherein the coating layer further comprises an organic film coating the inorganic oxide composite particles or the hard coat film. (9) The laminate according to (8), wherein the organic film comprises at least one compound selected from the group consisting of a fluorine-containing compound, an alkyl group-containing compound, and a silicone-based compound. (10) The laminate according to any one of (1) to (9), wherein the coating layer has a thickness of 100 to 3,000 nm. (11) The laminate according to any one of (1) to (10), wherein the surface of the coating layer has an arithmetic mean roughness Ra of 20 to 60 nm and a ten-point mean roughness Rz of 200 to 400 nm. (12) The laminate according to any one of (1) to (11), wherein the surface of the coating layer has a water contact angle of 150° or more. (13) The laminate according to any one of (1) to (12), wherein the surface of the coating layer has a water sliding angle of 15° or less. (14) The laminate according to any one of (1) to (13) above, which has a haze of 0.2 to 5%. (15) The laminate according to any one of (1) to (14) above, which is a water-repellent laminate.

[0110] (16) A method for producing a laminate, comprising: applying a coating liquid containing 30 to 95 vol % in terms of solid content of inorganic oxide composite particles, each of which has first inorganic oxide particles and second inorganic oxide particles having a particle size smaller than that of the first inorganic oxide particles supported on the surface of the first inorganic oxide particles, to at least one surface of a substrate, to form a coating layer having surface irregularities formed by the inorganic oxide composite particles. (17) A method for producing a laminate according to (16), comprising chemically bonding the first inorganic oxide particles and the second inorganic oxide particles to form the inorganic oxide composite particles. (18) A method for producing a laminate according to (16) or (17), wherein the coating liquid contains at least one adhesive selected from the group consisting of tetraethoxysilane, methyltriethoxysilane, and a bissilane compound, and the inorganic oxide composite particles are adhered to the substrate via the adhesive. (19) A method for producing a laminate, wherein the inorganic oxide composite particles are SiO ２ , Al ２ O ３ , ZrO ２ , TiO ２ , Fe ２ O ３ , CeO ２ , AgO, CuO, Cu ２(16) A method for producing a laminate according to any one of (16) to (18), comprising particles of at least one selected from the group consisting of O, ZnO, and composite oxides thereof. (20) A method for producing a laminate according to any one of (16) to (19), wherein the particle diameter of the first inorganic oxide particles is 2 to 5 times the particle diameter of the second inorganic oxide particles. (21) A method for producing a laminate according to any one of (16) to (20), wherein the particle diameter of the first inorganic oxide particles is 30 to 150 nm. (22) A method for producing a laminate according to any one of (16) to (21), wherein the particle diameter of the inorganic oxide composite particles is 40 to 350 nm. (23) A method for producing a laminate according to any one of (16) to (22), comprising coating the inorganic oxide composite particles with a hard coat film. (24) The method for producing a laminate according to (23) above, wherein the hard coat film contains at least one selected from the group consisting of a polysilazane compound, an alkoxysilane compound, and an isocyanate silane compound. (25) The method for producing a laminate according to (23) or (24) above, wherein the method includes coating the inorganic oxide composite particles or the hard coat film with an organic film. (26) The method for producing a laminate according to (25) above, wherein the organic film contains at least one selected from the group consisting of a fluorine-containing compound, an alkyl group-containing compound, and a silicone-based compound.

[0111] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" and "%" represent "parts by mass" and "% by mass", respectively. Examples 1 to 6 are working examples, and Examples 7 to 13 are comparative examples.

[0112] (Example 1) 1. Synthesis of Silica Composite Particles An organosilica sol "IPA-ST" (isopropyl alcohol dispersed silica sol, SiO) manufactured by Nissan Chemical Industries, Ltd., containing second inorganic oxide particles was used. ２8 mL of a silica dispersion containing first inorganic oxide particles (30% SiO , particle size: approximately 12 nm) was measured out, and 2.74 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane diluted to 10 M with chloroform was added thereto, followed by stirring at room temperature for 30 minutes to obtain silica dispersion A containing epoxy-modified silica particles. ２ 5 mL of silica dispersion A (30% silica dispersion, particle size: approximately 50 nm) was measured out, and 0.9 g of 3-aminopropyltrimethoxysilane diluted to 10 M with chloroform was added thereto, followed by stirring at room temperature for 30 minutes to obtain silica dispersion B containing amino-modified silica particles. 7 mL of silica dispersion A, 4.375 mL of silica dispersion B, and 76.25 g of 1-pentanol were mixed and ultrasonicated for 30 minutes to obtain silica composite particle dispersion C containing silica composite particles in which epoxy-modified silica particles were bonded to the surfaces of amino-modified silica particles.

[0113] 2. Preparation of Matrix 8.36 g of 0.463% nitric acid, 5.78 g of tetraethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.), and 0.10 g of methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBE-13") were added to 56.29 g of alcohol-based mixed solvent "AP-11" manufactured by Japan Alcohol Sales Co., Ltd., and the mixture was stirred at room temperature for one hour to obtain matrix liquid D, which serves as an adhesive between silica composite particles and between the silica composite particles and the substrate.

[0114] 3. Preparation of Coating Liquid 3 mL of matrix liquid D was added to 17.53 g of silica composite particle dispersion liquid C, and the mixture was ultrasonically stirred for 30 minutes. Thereafter, the mixture was passed through a 5 μm filter made of polytetrafluoroethylene (PTFE) to remove aggregates, and coating liquid E was obtained.

[0115] 4. Preparation of Organic Film-Forming Solution 2.38 g of trimethoxy(1H,1H,2H,2H-nonafluorohexyl)silane ("T2918" manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.686 g of 1% nitric acid were added to 67.62 g of isopropyl alcohol (manufactured by Junsei Chemical Co., Ltd.), and the mixture was stirred at room temperature for 3 hours. 2.5 g of this mixture was mixed with 27.5 g of a fluorine-based solvent ("ASAHIKLIN AC-6000" manufactured by AGC Corporation) to obtain Organic Film-Forming Solution G.

[0116] 5. Preparation of laminated body Float glass (thickness 2 mm, area 100 cm) was used as a substrate. ２ A glass substrate with a total light transmittance of 90% was prepared and washed with cerium oxide. The washed float glass was placed in a spin coater ("Opticoat MS-A200" manufactured by Mikasa Co., Ltd.), and Coating Solution E was spin-coated onto the float glass at 1500 rpm for 20 seconds to form a silica composite particle layer with a thickness of approximately 150 nm. Subsequently, perhydropolysilazane was spin-coated at 1500 rpm to form a hard coat film with a thickness of approximately 15 nm. The glass substrate was then baked at 550°C for 30 minutes. After baking, the surface was activated by plasma treatment, and Organic Film Forming Solution G was spin-coated at 500 rpm for 20 seconds to form a water-repellent film with a thickness of approximately 2 nm. The coating layer formed on the float glass was heated in an atmosphere of 50°C and 60% RH for 1 hour, and then washed with an alcohol-based mixed solvent "AP-1" manufactured by Japan Alcohol Sales Co., Ltd. Thereafter, the laminate was heated in an atmosphere of 50° C. and 60% RH for 24 hours to obtain a laminate.

[0117] (Examples 2 to 7) Laminates were prepared in the same manner as in Example 1, except that the addition ratio of the first inorganic oxide particles and the second inorganic oxide particles, the application speed of the hard coat film-forming coating solution, and the film thickness of the hard coat film were changed as shown in Table 1.

[0118] (Example 8) As the first inorganic oxide particles, "IPA-ST-ZL" (silica sol dispersed in isopropyl alcohol, SiO ２ A laminate was prepared in the same manner as in Example 1, except that matrix liquid D was used (composite particles: 30%, particle diameter: 100 nm) and the amount of composite particles added to matrix liquid D was changed as shown in Table 1.

[0119] (Example 9) As the first inorganic oxide particles, "IPA-ST-ZL" (silica sol dispersed in isopropyl alcohol, SiO ２ As the second inorganic oxide particles, organosilica sol "IPA-ST-L" (isopropyl alcohol dispersed silica sol, SiO ２ A laminate was produced in the same manner as in Example 1, except that a cellulose acylate copolymer (polymer: 30%, particle size: about 50 nm) was used.

[0120] Examples 10 to 13 Laminates were prepared in the same manner as in Example 1, except that the amount of composite particles added to matrix liquid D was changed as shown in Table 1.

[0121] [Measurement Method] (Measurement of Film Thickness) A cross section of the laminate was photographed using a high-resolution scanning electron microscope, and the film thickness was determined at any 10 points using the obtained image on the image analysis software "WinROOF2015", and the average value was calculated to be the film thickness of the coating layer.

[0122] (Measurement of porosity) The cross section of the laminate was photographed using a high-resolution scanning electron microscope, and the obtained image was subjected to binarization processing using image analysis software so that void portions and particle portions could be distinguished. The image was binarized using a threshold value of 155. The ratio of the void area to the area of ​​the coating layer at 1 / 2 the height on the substrate side (region A) relative to the coating layer thickness obtained above was calculated, and this was taken as the porosity of region A. In addition, the ratio of the void area to the area of ​​the coating layer at 1 / 2 the height from the surface (region B) relative to the coating layer thickness was calculated, and this was taken as the porosity of region B.

[0123] (Water Contact Angle) The contact angle of pure water placed on the surface of the coating layer side of the laminate was measured using a contact angle meter (DM-701 model, manufactured by Kyowa Interface Science Co., Ltd.) A 2 μL water droplet dispensed from the tip of a syringe was placed in contact with the surface of the coating layer, or if the water repellency was too high and the water droplet did not adhere to the film surface, it was dropped, and the contact angle was measured at three different points on the surface of the coating layer using the contact angle meter, and the average value was calculated as the water contact angle.

[0124] (Water Sliding Angle) The water sliding angle was measured using pure water as follows. A 30 μL water droplet was placed in contact with the surface of the coating layer side of the laminate held horizontally, or was dropped if the water repellency was too high and the water droplet did not adhere to the film surface. The laminate was then tilted at a rate of 4° per minute, and the angle (tilt angle) between the laminate and the horizontal plane was measured when the water droplet moved 1 mm on the surface of the coating layer. Measurements were taken at three different locations on the surface of the coating layer, and the average value was calculated as the water sliding angle.

[0125] (Haze) The haze of the laminate was measured using a haze meter (manufactured by Murakami Color Research Laboratory, model number: HM-65L2).

[0126] (Arithmetic mean roughness (Ra) and ten-point mean roughness (Rz)) Measurements were made using a scanning probe microscope (manufactured by Hitachi High-Tech Corporation, model number: SPA400). The images obtained were analyzed using the accompanying software "Spisel32." The arithmetic mean roughness (Ra) of the surface of the coating layer of the laminate was measured based on the method described in JIS B0601:2001 (ISO4287:1997), and the ten-point mean roughness (Rz) was obtained as the value specified in IS B0601:2001.

[0127] (Abrasion Resistance) Using a reciprocating traverse tester (manufactured by KNT Corporation, custom-made product), a flannel cloth conforming to JIS L0803 was applied to the surface of the laminate at a pressure of 500 g / 4 cm. ２ The laminate surface was abraded by applying a load of 100°. After 10 and 500 reciprocating strokes, the water contact angle was measured by the above method, and the abrasion resistance was evaluated based on the following evaluation criteria. [Evaluation criteria] A: Water contact angle of 100° or more after 500 abrasions B: Water contact angle of less than 100° after 500 abrasions and water contact angle of 100° or more after 10 abrasions C: Water contact angle of less than 100° after 10 abrasions

[0128] The results are shown in Table 1. Scanning electron microscope images of Examples 1, 2, and 7, which were used to calculate the voids in Region A, are shown in Figure 2. In Figure 2, (a) is the image of Example 1, (b) is the image of Example 2, and (c) is the image of Example 7.

[0129]

[0130] As shown in Table 1, the laminates of Examples 1 to 6 had a water contact angle of 150° or more and a water sliding angle of 15° or less, demonstrating excellent water repellency. These laminates also had excellent abrasion resistance, maintaining water repellency almost equivalent to that of the initial state even when the surface of the coating layer was worn down by abrasion. Furthermore, the laminates of Examples 1 to 6 also had a low haze of 5 or less and high transparency.

[0131] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made thereto without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2023-184706) filed on October 27, 2023, the contents of which are incorporated herein by reference.

[0132] REFERENCE SIGNS LIST 1 substrate 2 coating layer 3 inorganic oxide composite particles 4 hard coat film 5 organic film 6 first inorganic oxide particles 7 second inorganic oxide particles 10 laminate

Claims

1. A laminate comprising a substrate and a coating layer provided on at least one surface of the substrate, the coating layer containing a plurality of inorganic oxide composite particles, the inorganic oxide composite particles each having a first inorganic oxide particle as a core and a second inorganic oxide particle held on the surface of the first inorganic oxide particle and having a particle diameter smaller than that of the first inorganic oxide particle, the surface of the coating layer is formed with an uneven shape by the inorganic oxide composite particles, and in a cross section in the thickness direction of the laminate, a region A of the coating layer that is 1 / 2 the thickness from the surface of the substrate has a porosity of 33 to 55%.

2. The inorganic oxide composite particles are SiO ２ , Al ２ O ３ , ZrO ２ , TiO ２ , Fe ２ O ３ , CeO ２ , AgO, CuO, Cu ２ The laminate according to claim 1 , comprising at least one particle selected from the group consisting of O, ZnO, and composite oxides thereof.

3. The laminate according to claim 1 or 2, wherein the particle size of the first inorganic oxide particles is 2 to 5 times the particle size of the second inorganic oxide particles.

4. The laminate according to claim 1 or 2, wherein the particle diameter of the first inorganic oxide particles is 30 to 150 nm.

5. The laminate according to claim 1 or 2, wherein the particle diameter of the inorganic oxide composite particles is 40 to 350 nm.

6. The laminate according to claim 1 or 2, wherein the coating layer further comprises a hard coat film that coats the inorganic oxide composite particles.

7. The laminate according to claim 6, wherein the hard coat film contains at least one selected from the group consisting of a polysilazane compound, an alkoxysilane compound, and an isocyanate silane compound.

8. The laminate according to claim 6, wherein the coating layer further comprises an organic film that coats the inorganic oxide composite particles or the hard coat film.

9. The laminate according to claim 8, wherein the organic film contains at least one compound selected from the group consisting of fluorine-containing compounds, alkyl group-containing compounds, and silicone-based compounds.

10. The laminate according to claim 1 or 2, wherein the coating layer has a thickness of 100 to 3,000 nm.

11. The laminate according to claim 1 or 2, wherein the surface of the coating layer has an arithmetic mean roughness Ra of 20 to 60 nm and a ten-point mean roughness Rz of 200 to 400 nm.

12. The laminate according to claim 1 or 2, wherein the surface of the coating layer has a water contact angle of 150° or more.

13. The laminate according to claim 1 or 2, wherein the water sliding angle of the surface of the coating layer is 15° or less.

14. The laminate according to claim 1 or 2, having a haze of 0.2 to 5%.

15. The laminate according to claim 1 or 2, which is a water-repellent laminate.

16. A method for producing a laminate, comprising: applying a coating liquid containing 30 to 95 vol. %, calculated as solid content, of inorganic oxide composite particles in which first inorganic oxide particles are supported on the surfaces of the first inorganic oxide particles and second inorganic oxide particles having a particle size smaller than that of the first inorganic oxide particles, to at least one surface of a substrate, and forming a coating layer having irregularities on its surface formed by the inorganic oxide composite particles.

17. The method for producing a laminate according to claim 16, comprising chemically bonding the first inorganic oxide particles and the second inorganic oxide particles to form the inorganic oxide composite particles.

18. A method for producing a laminate described in claim 16 or 17, wherein the coating liquid contains at least one selected from the group consisting of tetraethoxysilane, methyltriethoxysilane, and a bis-silane compound as an adhesive, and the method includes adhering the inorganic oxide composite particles to the substrate via the adhesive.

19. The inorganic oxide composite particles are SiO ２ , Al ２ O ３ , ZrO ２ , TiO ２ , Fe ２ O ３ , CeO ２ , AgO, CuO, Cu ２ The method for producing a laminate according to claim 16 or 17, comprising particles of at least one selected from the group consisting of O, ZnO and composite oxides thereof.

20. The method for producing a laminate according to claim 16 or 17, wherein the particle size of the first inorganic oxide particles is 2 to 5 times the particle size of the second inorganic oxide particles.

21. The method for producing a laminate according to claim 16 or 17, wherein the particle diameter of the first inorganic oxide particles is 30 to 150 nm.

22. The method for producing a laminate according to claim 16 or 17, wherein the particle diameter of the inorganic oxide composite particles is 40 to 350 nm.

23. A method for producing a laminate according to claim 16 or 17, comprising coating the inorganic oxide composite particles with a hard coat film.

24. The method for producing a laminate according to claim 23, wherein the hard coat film contains at least one selected from the group consisting of a polysilazane compound, an alkoxysilane compound, and an isocyanate silane compound.

25. A method for producing a laminate according to claim 23, comprising coating the inorganic oxide composite particles or the hard coat film with an organic film.

26. The method for producing a laminate according to claim 25, wherein the organic film contains at least one compound selected from the group consisting of fluorine-containing compounds, alkyl group-containing compounds, and silicone-based compounds.

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