WO2018051958A1

WO2018051958A1 - Antifouling article

Info

Publication number: WO2018051958A1
Application number: PCT/JP2017/032745
Authority: WO
Inventors: 万江美増田; 広和小平
Original assignee: 旭硝子株式会社
Priority date: 2016-09-16
Filing date: 2017-09-12
Publication date: 2018-03-22

Abstract

The present invention provides an antifouling article that has a superb antifouling property and also exhibits excellent resistance to wear. Provided is an antifouling article that has a substrate and an antifouling layer which is disposed on the substrate, and which has, on the surface thereof, a plurality of protrusions including a uneven layer that contains a binder and an aggregate of high-hardness nanoparticles, wherein, after the surface of the antifouling layer is reciprocally rubbed with a cotton cloth placed thereon conforming to the requirements of JIS L0803 for 100 times under a pressure of 1.23×10⁴ N/m² and is washed with water, the antifouling layer exhibits an antifouling index ΔHx of 12% or less, as measured by a prescribed method.

Description

Antifouling article

The present invention relates to an antifouling article, and in particular, to an antifouling article having excellent antifouling properties and excellent wear resistance.

If sand, muddy water, rainwater, or the like adheres to the surface of a transparent substrate such as glass, the substrate surface becomes dirty and the transparency is impaired. Therefore, various methods have been provided so far for techniques for forming an antifouling layer that makes it difficult to get dirt on the substrate surface. Specifically, an antifouling article has been proposed that has a hydrophilic microporous antifouling layer on a substrate surface in which an aggregate of silica fine particles such as pearl necklace-like silica is bound with a siliceous binder (for example, a patent) Reference 1).

The antifouling layer in the antifouling article of Patent Document 1 has fine irregularities on the surface, so that the contact area when dirt adheres to the antifouling layer surface can be reduced, thereby exhibiting excellent antifouling properties. Is. The uneven shape on the antifouling layer surface is formed by reflecting the accumulated shape of the silica fine particle aggregate.

Further, in the antifouling article of Patent Document 1, the antifouling layer is not only difficult to get dirty due to the uneven shape of the surface, but also has the effect that the dirt attached due to being hydrophilic is spread and washed away by the attachment of rainwater etc. It is known that there is. However, the antifouling layer using silica fine particles as described in Patent Document 1 is excellent in antifouling properties as described above, but a visible scratch is generated on the antifouling layer due to wear during long-term use. However, it was difficult to say that the abrasion resistance was insufficient.

On the other hand, for example, Patent Document 2 describes a coating composition containing nano diamond particles having high hardness and a resin. However, this coating composition is used for forming a smooth surface film having excellent transparency, high strength and high elastic modulus, and does not have an antifouling function. That is, Patent Document 2 does not describe a technique for forming an antifouling film having an uneven shape on the surface by adjusting the deposition state of nanodiamond particles.

International Publication No. 2016/010080 JP 2011-26390 A

The present invention has been made from the above viewpoint and aims to provide an antifouling article having excellent antifouling properties and excellent wear resistance.

The present invention comprises the following.
[1] An antifouling article comprising a substrate and an antifouling layer disposed on the substrate and having a plurality of protrusions including a concavo-convex layer containing an aggregate of high hardness nanoparticles and a binder on the surface,
After placing a cotton cloth specified in JIS L0803 on the surface of the antifouling layer, applying a pressure of 1.23 × 10 ⁴ N / m ² and reciprocating 100 times, and then washing the antifouling article with water, An antifouling article having an antifouling index ΔHx measured by the following method of 12% or less.
(Measurement method of antifouling index ΔHx)
With the main surface of the antifouling article horizontal, the mixed powder for evaluation (2.3% by mass of carbon black 1 (particle size 0.002 to 0.028 μm), 9.3% by mass on the surface of the antifouling layer) % Carbon black 2 (12 types of JIS test powder 1), 62.8% by mass of yellow ocher (natural ocher for pigments), 20.9% by mass of calcined Kanto loam (8 of JIS test powder 1) Seed) and 4.7% by mass of silica powder (mixed powder of three kinds of JIS test powder 1) are sprayed at a rate of 0.02 g / cm ² and allowed to stand for 10 seconds. Next, an aluminum test plate was used, and the antifouling article was tilted so that the angle formed by the main surface of the test plate and the surface of the test plate was 135 ° from the height of 3 cm above the test plate. The haze value is measured after removing the evaluation mixed powder by repeating twice the operation of moving the lower end of the antifouling article to the surface of the test plate at a speed of / sec. The haze value measurement is carried out five times, and the average is taken as the haze value after the test, and the value obtained by subtracting the haze value before the test from the haze value after the test is taken as the antifouling index ΔHx.
[2] The antifouling article according to [1], wherein the high-hardness nanoparticles have a Mohs hardness of 12 or more.
[3] The antifouling article according to [1] or [2], wherein the antifouling layer has a surface Ra of 2 to 6 nm.
[4] The antifouling article according to [1] to [3], wherein the high-hardness nanoparticles have an average primary particle diameter of 1 to 50 nm.
[5] Among the protrusions, the protrusions T adjacent to each other with respect to the protrusion T having a height of 90% or more with reference to the protrusion having the maximum height from the surface of the base on which the antifouling layer is disposed. The average distance between the apexes of the body T is 50 to 1,000 nm, and the ratio of the total area of the bottom surface of the protrusion T to the area of the substrate on which the antifouling layer is disposed is 12 to 70% [1. ] To [4] antifouling article.
[6] The antifouling article according to [1] to [5], wherein the volume ratio of the high hardness nanoparticles to the binder is 30/70 to 70/30.
[7] The antifouling article according to [1] to [6], wherein the antifouling layer further has a water repellent layer on the uneven layer.
[8] The antifouling article according to [7], wherein the antifouling layer further has an intermediate layer between the uneven layer and the water repellent layer.
[9] The antifouling article according to [1] to [8], wherein the antifouling layer has a surface Martens hardness of 1000 MPa or more.

According to the present invention, an antifouling article having excellent antifouling properties and excellent wear resistance can be provided.

It is a figure which shows typically the cross section of an example of the antifouling article based on this invention. It is a figure which shows typically the cross section of another example of the antifouling | stain-proof article based on this invention. It is a scanning electron micrograph (800,000 times) of the antifouling layer surface of the antifouling article obtained in Example 2 of the Examples.

In this specification, the term “process” includes not only an independent process but also a case where the intended purpose of the process is achieved even if it cannot be clearly distinguished from other processes. A numerical range indicated by using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. Further, the content of each component in the composition means the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition.

In this specification, the average primary particle diameter of the particles is a particle diameter determined by observation with a scanning electron microscope. The secondary particle diameter is a particle diameter measured by a dynamic light scattering method.

[Anti-fouling article]
Hereinafter, embodiments of the antifouling article of the present invention will be described with reference to the drawings. Note that the present invention is not limited to these embodiments, and these embodiments can be changed or modified without departing from the spirit and scope of the present invention.

FIG. 1 and FIG. 2 are diagrams schematically showing a cross section of one example and another example of the antifouling article according to the present invention. An antifouling article 1 </ b> A shown in FIG. 1 includes a base 2 and an antifouling layer 6 disposed on the base 2. The antifouling layer 6 is composed of a concavo-convex layer 5 containing an aggregate of high hardness nanoparticles 3 and a binder 4 and has a plurality of protrusions 9.

The antifouling article 1B shown in FIG. 2 has a base 2 and an antifouling layer 6 disposed on the base 2. The antifouling layer 6 has a concavo-convex layer 5 including an aggregate of high hardness nanoparticles 3 and a binder 4, an intermediate layer 7, and a water repellent layer 8 in order from the substrate 2 side. The surface shape of the antifouling layer 6 reflects the surface shape of the uneven layer 5 substantially as it is, and has a plurality of protrusions 9.

In the antifouling article 1A and the antifouling article 1B, a cotton cloth specified in JIS L0803 is placed on the surface of the antifouling layer 6, and a pressure of 1.23 × 10 ⁴ N / m ² is applied to reciprocate 100 times. After rubbing and then washing the antifouling article with water, the antifouling index ΔHx (hereinafter also simply referred to as “antifouling index ΔHx”) measured by the above method is 12% or less.

The antifouling article of the present invention has a plurality of protrusions on the surface of the antifouling layer, thereby reducing the contact area of dirt against the antifouling article. As a result, dirt is less likely to adhere to the antifouling article, and thus the antifouling article of the present invention has excellent antifouling properties. In the antifouling article of the present invention, since the high hardness nanoparticles are used for the formation of the protrusions, the abrasion resistance is also excellent.

<Substrate>
The substrate is not particularly limited as long as it has a surface on which an antifouling layer can be disposed. The material of the substrate is not particularly limited, and examples thereof include glass, plastic, metal, ceramics, and combinations thereof (for example, composite materials and laminated materials). The substrate is preferably a light transmissive substrate made of glass or plastic. The glass may be a tempered glass subjected to a physical tempering treatment or a chemical tempering treatment, or may be a laminated glass in which a plurality of glass plates are laminated via an adhesive layer.

The shape of the substrate is not particularly limited, and examples thereof include a flat plate shape and a shape having a curvature on the entire surface or a part thereof. The thickness of the substrate is not particularly limited and can be appropriately selected depending on the use of the antifouling article. The thickness of the substrate is preferably 1 to 10 mm from the viewpoint of ease of handling.

<Anti-fouling layer>
The antifouling layer 6 is disposed on the substrate 2 and has an uneven layer 5 including an aggregate of high hardness nanoparticles 3 and a binder 4 as an essential layer. In the antifouling article of the present invention, the antifouling layer may be composed of only the uneven layer 5 as in the antifouling article 1A shown in FIG. 1, and the unevenness as in the antifouling article 1B shown in FIG. The structure which has the water-repellent layer 8 on the layer 5 may be sufficient. In addition, the antifouling layer 6 of the antifouling article 1B has a configuration including the uneven layer 5, the water repellent layer 8, and the intermediate layer 7 disposed therebetween. However, when the antifouling layer of the antifouling article has a water-repellent layer on the concavo-convex layer, a configuration without an intermediate layer may be used.

The concavo-convex layer 5 is a layer that includes aggregates of the high hardness nanoparticles 3 and the binder 4 and has concavo-convex surfaces. The plurality of protrusions 9 on the surface of the antifouling layer 6 correspond to the convex portions of the uneven layer 5 on the surface in the antifouling article 1A. The concave portion 10 of the concavo-convex layer 5 is a portion where the protrusions 9 are not formed, and has a surface substantially parallel to the surface on which the antifouling layer of the substrate is disposed (hereinafter referred to as “substrate surface”). Further, in the antifouling article 1 </ b> B, the protrusions 9 are those in which the uneven shape of the uneven layer 5 on the surface is directly exposed on the surface of the antifouling layer 6. Since the antifouling layer 6 has the fine protrusions 9 on the surface, in the antifouling articles 1 </ b> A and 1 </ b> B, dirt hardly adheres to the antifouling layer 6.

When the antifouling layer has a water-repellent layer on the uneven layer, the surface energy is small on the antifouling layer surface and the surface frictional force is small. Therefore, the antifouling layer surface is not easily worn, and for example, even when the dirt adhering to the antifouling layer surface is wiped off with a cloth or the like, the antifouling performance is not easily lowered.

In the present specification, the convex portion of the concave-convex layer and the protrusion of the antifouling layer refer to a shape having an apex that is higher in height from the base surface than a concave portion having a surface substantially parallel to the base surface. The shape of the protrusions included in the antifouling layer is not particularly limited, and examples thereof include a substantially quadrangular pyramid, a substantially triangular pyramid, and a substantially cone. When a region from the apex of the protrusion to a height of 50% is approximated to a partial spherical surface, the radius of curvature of the partial spherical surface is preferably 5 nm or more, and more preferably 5 nm to 15 nm. Further, the height of the protrusion is preferably 10 nm or more, more preferably 30 to 200 nm. The height of the protrusion is the height from the substrate surface to the apex of the protrusion, and can be measured using a scanning electron microscope. The height of the recess, that is, the distance from the substrate surface to the surface substantially parallel to the substrate surface of the recess is preferably 10 to 50 nm on average.

The height of the protrusions and the recesses in the antifouling layer is, for example, in the range of 1 μm × 1 μm randomly extracted from the scanning electron micrograph image of the antifouling layer surface as shown in FIG. It is obtained using image conversion software such as J (trade name; manufactured by NIH). In the following description, measurement using a scanning electron microscope refers to measurement performed by such image conversion software, for example, image J (trade name; manufactured by NIH).

The number of protrusions in the antifouling layer is preferably 30 to 100 / μm ^{2, and} more preferably 50 to 100 / μm ² . The number of protrusions can be measured, for example, by observing the film surface with a scanning electron microscope.

The size of the bottom surface of the protrusion is preferably 10 to 700 nm, more preferably 30 to 200 nm. The bottom surface of the protrusion means the bottom surface of the protrusion obtained when the protrusion is cut by a surface parallel to the substrate surface at the average height of the recess. The size of the bottom surface of the protrusion is the size of the protrusion. The diameter of the circle in which the bottom shape is inscribed is used. The bottom size of the protrusion can be measured using a scanning electron microscope. The average value of the angle between the bottom surface and the side surface of the protrusion is not particularly limited, but is preferably 10 to 90 °, more preferably 20 to 70 °. If the angle between the bottom surface and the side surface of the protrusion is 10 ° or more, a steeper protrusion can be obtained.

In the antifouling layer, with respect to the protrusion T having a height of 90% or more on the basis of the protrusion having the maximum height from the substrate surface, the average value of the distances between the apexes of the adjacent protrusions T (hereinafter, It is preferably also referred to as “distance between vertices”) of 50 to 1,000 nm. The distance between the vertices is more preferably 50 to 800 nm, and particularly preferably 50 to 500 nm. That the distance between vertices is 50 nm or more means that the interval between the irregularities formed by the protrusions T on the surface of the antifouling layer is large. When the distance between the vertices is 50 nm or more, the adsorption of dirt due to capillary action can be suppressed. As a result, oil stains and the like are hardly attached, and even if attached, they can be easily removed.

The distance between vertices can be measured with a scanning electron microscope. Specifically, the distance between the vertices is a protrusion having the maximum height among protrusions existing in a predetermined region in a direction parallel to the surface having the antifouling layer of the substrate from a surface photograph of the antifouling article. Select a body, select a protrusion T having a height of 90% or more, measure the distance between vertices of adjacent protrusions T (that is, the distance between the vertices), and calculate the average value. To do.

The ratio (%) of the total area of the bottom surface of the protrusion T to the area of the substrate surface on which the antifouling layer is disposed (hereinafter also referred to as “protrusion coverage”) is preferably 12 to 70%. The area of the bottom surface of the protrusion T is an area measured on the bottom surface of the protrusion T obtained when the protrusion T is cut along a plane parallel to the substrate surface at the average height of the recesses. Can be measured. When the convex portion coverage is 12% or more, the antifouling layer has a large proportion of high-hardness nanoparticle aggregates and protrusions containing a binder that can come into contact with dirt, so that sufficient antifouling properties can be obtained. . If it is 70% or less, the wear resistance is excellent. The convex portion coverage is preferably 15 to 70%, more preferably 20 to 70%, and particularly preferably 50 to 70%. The convex portion coverage is calculated based on the total area of the bottom surface of the protrusion T measured in this manner in a predetermined region on the base surface on which the antifouling layer is disposed.

The surface Ra of the antifouling layer is preferably 2 to 6 nm. If Ra is 2 nm or more, contact between the portion having a film thickness thinner than the apex of the protrusion and the dirt can be suppressed, and more excellent antifouling properties can be obtained. If it is 6 nm or less, it is excellent in abrasion resistance strength. A more preferable range of the surface Ra of the antifouling layer varies depending on the type of the high-hardness nanoparticles. For example, when the high-hardness nanoparticles are nanodiamond, the surface Ra of the antifouling layer is more preferably 3 to 6 nm, and particularly preferably 4 to 6 nm.

In this specification, “Ra” refers to the arithmetic average roughness calculated in accordance with JIS B 0031: 2003 on the specimen surface. Ra can be measured, for example, with a scanning probe microscope.

The film thickness of the antifouling layer is not particularly limited, but is preferably 20 to 350 nm, more preferably 30 to 300 nm, and particularly preferably 50 to 300 nm. If the film thickness of the antifouling layer is 20 nm or more, the antifouling property tends to be high, and if it is 350 nm or less, the mechanical strength is excellent. Here, the film thickness is 10 in descending order from the protrusion having the maximum height in the range of 1.5 μm in the direction parallel to the surface having the antifouling layer of the substrate from the film cross-sectional image obtained by an electron microscope or the like. This is a value obtained by extracting 10 points up to the first protrusion and averaging the heights of the protrusions at the 10 points.

Each layer constituting the antifouling article 1A and the antifouling article 1B shown in FIG. 1 and FIG. 2 will be described below. In the antifouling layer 6 of the antifouling article 1A and the antifouling article 1B, the uneven layer 5 is the same layer.

(Uneven layer)
The concavo-convex layer 5 is a layer that includes the aggregates of the high hardness nanoparticles 3 and the binder 4 that are disposed on the base 2, and has a convex portion corresponding to the protrusion 9. The volume ratio of the high-hardness nanoparticles and the binder in the uneven layer (hereinafter also referred to as “particle / binder”) is preferably 30/70 to 70/30, more preferably 35/65 to 65/35, More preferred is 60-60 / 40.

If the particle / binder is 30/70 or more, a concavo-convex layer having an appropriate distance between the apexes of the protrusions T can be formed on the surface of the substrate, so that the antifouling property tends to be high. For example, the adhesion between the substrate and the uneven layer tends to be high.

(Agglomerates of high hardness nanoparticles)
The aggregate of the high-hardness nanoparticles 3 is an aggregate of nanoparticles made of a high-hardness material, and is particularly suitable as long as it can form an aggregate with the binder 4 and form the uneven layer 5 having convex portions on the surface. It is not limited. As the high hardness material constituting the high hardness nanoparticles, a material having a Mohs hardness of 12 or more is preferable, and a material having a Mohs hardness of 15 or more is more preferable.

Specific examples of high-hardness nanoparticles include particles such as nanodiamond (Mohs hardness 15), α-alumina particles (Mohs hardness 12), silicon carbide particles (Mohs hardness 13), and the like. The high-hardness nanoparticles may be one type or a combination of two or more types. Nanodiamonds are preferred as the high hardness nanoparticles.

The average primary particle diameter of the high hardness nanoparticles is preferably 1 to 50 nm, more preferably 3 to 40 nm, still more preferably 5 to 30 nm, and particularly preferably 5 to 20 nm. When the average primary particle diameter of the high-hardness nanoparticles is 1 nm or more, it becomes easy to form convex portions, and the antifouling property tends to be improved. Moreover, if the average primary particle diameter of the high hardness nanoparticles is 50 nm or less, the haze value can be reduced.

The secondary particle diameter indicating the size of the aggregate of high hardness nanoparticles is preferably 1 to 100 nm, more preferably 5 to 80 nm, and particularly preferably 10 to 50 nm.

(binder)
The binder 4 is not particularly limited as long as it can form an aggregate with the aggregates of the high-hardness nanoparticles 3 and can form the uneven layer 5 having convex portions on the surface. As the binder, an inorganic binder is preferable in terms of excellent durability. The binder is preferably a hydrophilic inorganic binder because the antifouling property is increased. Moreover, since the uneven | corrugated layer formed using the hydrophilic inorganic binder increases the amount of OH groups on the surface, the water-repellent layer 8 is formed on the uneven layer 5 through the water-repellent layer 8, preferably the intermediate layer 7. In this case, the water repellent layer forming composition and the intermediate layer forming composition are preferable because they are easily bonded.

Examples of hydrophilic inorganic binders include metal oxides such as silica, alumina, titania, zirconia, tantalum oxide and tin oxide. The binder is more preferably a silica binder in terms of ease of handling. The silica binder preferably has a small alkali component content. As a silica binder having a low alkali content, a dehydrated alkali silicate compound obtained by removing a part of an alkali metal from a hydrolysis condensate of an alkoxysilane compound or an alkali metal salt of silicic acid (hereinafter also referred to as “demineralized silicic acid”). )). These hydrolysis condensates may contain unreacted silanol groups (Si—OH) groups.

The binder may be a mixture of two or more binders. 50 mass% or more is preferable and, as for the silica content rate in a binder, 75 mass% or more is more preferable.

The concavo-convex layer 5 can contain further components in addition to the aggregates of the high hardness nanoparticles 3 and the binder 4 as long as the effects of the present invention are not impaired. Additional components include surfactants, antifoaming agents, leveling agents, UV absorbers, viscosity modifiers, antioxidants, fungicides, pigments and the like. The total content of the further components is preferably 5% by mass or less, more preferably 1% by mass or less in the uneven layer.

(Water repellent layer)
The antifouling article of the present invention preferably has a water repellent layer 8 on the uneven layer 5 like the antifouling layer 6 of the antifouling article 1B shown in FIG. The thickness of the water repellent layer 8 is preferably substantially uniform. If the thickness of the water repellent layer 8 is reduced at the tip of the protrusion 9, the water repellency of the antifouling layer 6 may be reduced, or the dirt removability may be reduced.

The water repellent layer 8 is preferably made of a silane compound containing fluorine, since the water repellency becomes high. The water repellent layer 8 is more preferably made of a hydrolyzed condensate of fluorine-containing alkoxysilane.

(Middle layer)
In the antifouling article of the present invention, when the antifouling layer has a water-repellent layer on the uneven layer, an intermediate between the uneven layer 5 and the water-repellent layer 8 as in the antifouling article 1B shown in FIG. It is preferable to have the layer 7. By having the intermediate layer 7, antifouling properties and water-repellent wear resistance can be improved. Silica is preferable as a material used for forming the intermediate layer.

<Properties of antifouling article>
By having the antifouling layer, the antifouling article of the present invention has excellent antifouling properties against various stains and is excellent in wear resistance. Specifically, the dirt that is subject to antifouling properties is inorganic dirt such as atmospheric dust, alkali residue from the concrete wall (water dry spots), water stains, and glass burns. Organic dirt such as smoke in the atmosphere, automobile exhaust, cigarette smoke, and oil. The antifouling article has a better antifouling effect against dust and oil stains.

The antifouling property of the antifouling article can be evaluated by, for example, an antifouling index ΔHx (hereinafter, also simply referred to as “ΔHx”) measured by the following method. The initial ΔHx of the antifouling article is also referred to as ΔHxi. In the antifouling article of the present invention, ΔHxi is preferably 1.5% or less, more preferably 1.0% or less, and further preferably 0.5% or less. Note that ΔHx is an index for evaluating the antifouling property against powder such as sand, and as ΔHx is smaller, it means that powder such as sand is less likely to adhere and is less likely to become dirty even when used outdoors for a long time.

(Measurement method of antifouling index ΔHx)
The main surface of the antifouling article is leveled, and the following mixed powder for evaluation is sprayed on the surface of the antifouling layer at a rate of 0.02 g / cm ² and allowed to stand for 10 seconds. Next, an aluminum test plate was used, and the antifouling article was tilted so that the angle formed by the main surface of the test plate and the surface of the test plate was 135 ° from the height of 3 cm above the test plate. The haze value is measured after removing the evaluation mixed powder by repeating the operation of moving the antifouling article at a speed of / sec until the lower end of the antifouling article contacts the surface of the test plate. The haze value is measured five times, the average is taken as the haze value after the test, and the value obtained by subtracting the haze value (%) before the test from the haze value after the test (%) is taken as the antifouling index ΔHx (%). .

The mixed powder for evaluation is a mixed powder used in an antifouling evaluation test conducted by the Public Works Research Center, 2.3% by mass of carbon black 1 (particle size: 0.002 to 0.028 μm) 9.3 mass% carbon black 2 (12 kinds of powder 1 for JIS test), 62.8 mass% yellow ocher (natural ocher for pigment) and 20.9 mass% calcined Kanto loam (for JIS test) 8 types of powder 1) and 4.7% by mass of silica powder (3 types of powder 1 for JIS test). JIS test powder 1 is specified in JIS Z 8901.

Further, the abrasion resistance of the antifouling article can be evaluated by ΔHx measured after the following abrasion resistance test 1. Hereinafter, ΔHx after the abrasion resistance test 1 is also referred to as ΔHxr1. The antifouling article of the present invention has ΔHxr1 of 12% or less and is excellent in wear resistance. ΔHxr1 is preferably 10% or less, and more preferably 5% or less.

(Abrasion resistance test 1)
Place the cotton cloth specified in JIS L0803 on the surface of the antifouling layer of the antifouling article, apply a pressure of 1.23 × 10 ⁴ N / m ² and rub it back and forth 100 times, and then wash the antifouling article with water To do.

Note that the abrasion resistance of the antifouling article can be evaluated at a higher level of abrasion resistance by ΔHx measured after the following abrasion resistance test 2 under conditions more severe than those described above. Hereinafter, ΔHx after the abrasion resistance test 2 is also referred to as ΔHxr2. In the antifouling article of the present invention, ΔHxr2 is preferably 15% or less, ΔHxr2 is more preferably 12% or less, and further preferably 10% or less.

(Abrasion resistance test 2)
Place the cotton cloth specified in JIS L0803 on the surface of the antifouling layer of the antifouling article, apply a pressure of 2.95 × 10 ⁴ N / m ² and rub it back and forth 500 times, and then wash the antifouling article with water To do.

In the antifouling article of the present invention, for example, when the antifouling layer has a water repellent layer on the uneven layer, it is easy to achieve 10% or less of ΔHxr2. Furthermore, when the antifouling layer 6 has the water repellent layer 8 through the intermediate film 7 on the uneven layer 5 as in the antifouling article 1B shown in FIG. 2, it is easy to achieve 5% or less of ΔHxr2. In the antifouling article of the present invention, when the antifouling layer has a water-repellent layer on the uneven layer, the friction coefficient of the surface of the antifouling layer is small, and abrasion due to rubbing hardly occurs. Therefore, even when the attached dirt is wiped off with a cloth or the like, the antifouling performance is not easily lowered. In particular, when the antifouling layer has a water-repellent layer on the uneven layer through an intermediate film, the effect of suppressing the deterioration of the antifouling performance is high.

In the antifouling article of the present invention, for example, in the antifouling article, when the antifouling layer has a water-repellent layer on the uneven layer, the sessile drop method specified in JIS R3257: 1999 is applied mutatis mutandis. A 1 μL water droplet is dropped on the surface of the soil layer, and the water contact angle measured after 3 seconds (hereinafter, the water contact angle measured by the method is simply referred to as “water contact angle”) is approximately 110 ° or more. be able to. The water contact angle is an evaluation index of water repellency. If it is 80 ° or more, the water repellency is excellent.

In the antifouling article of the present invention, the water contact angle on the surface of the antifouling layer is more preferably 100 ° or more, and further preferably 110 ° or more. Note that a contact angle of 150 ° or less is preferable because productivity increases. Thus, when the surface of the antifouling layer has water repellency, the adhesion force acting between the dirt and the antifouling layer is small. Therefore, not only dirt containing moisture such as mud dirt is hard to adhere, but even if dirt adheres, the attached dirt is easily removed by wind or gravity.

In the antifouling article of the present invention, the antifouling layer has excellent water repellency and abrasion resistance when the antifouling layer has a water repellent layer on the uneven layer via an intermediate film. For example, the antifouling article having such a configuration can have a water contact angle measured after the wear resistance test 2 of approximately 95 ° or more.

Furthermore, in the antifouling article of the present invention, the Martens hardness of the antifouling layer surface is preferably 1000 MPa or more, more preferably 1300 MPa or more. A Martens hardness of 1000 MPa or more is preferred because of excellent wear resistance.

In this specification, the Martens hardness is measured by using an indentation test apparatus (Fischer, Picodenter HM500), indentation load of 0.03 mN, holding time of 5 seconds, loading speed and unloading speed of 0.05 mN / 5 seconds. The Martens hardness measured as.

<Method for producing antifouling article>
The antifouling article of the present invention can be produced, for example, by the method described below. In the following description, as shown in FIG. 2, the concavo-convex layer 5, the intermediate layer 7, and the substrate 2, the aggregates of the high-hardness nanoparticles 3 arranged on the substrate 2, and the binder 4 are sequentially arranged from the substrate 2 side. The case of the antifouling article 1B having the antifouling layer 6 having the water repellent layer 8 will be described as an example. Note that the antifouling article 1A shown in FIG. 1 can be manufactured by a method in which the intermediate layer 7 and the water repellent layer 8 are not formed in the following method. Further, in the following method, when the intermediate layer 7 is not formed, a base, a concavo-convex layer containing agglomerates of high-hardness nanoparticles and a binder arranged in this order from the base side, and a water-repellent layer are arranged on the base. An antifouling article having an antifouling layer can be produced.

A step of preparing a concavo-convex layer-forming composition comprising an aggregate of high-hardness nanoparticles and a binder precursor, an intermediate layer-forming composition, a water-repellent layer-forming composition, and a substrate (referred to as a “preparation step”); A step of applying a concavo-convex layer forming composition on a substrate to form a concavo-convex layer (referred to as a “concave layer forming step”), and an intermediate layer forming composition applied on the formed concavo-convex layer. A step of forming a layer (referred to as “intermediate layer forming step”), and a step of applying a water repellent layer forming composition on the formed intermediate layer to form a water repellent layer (“water repellent layer forming step”). And).

(Preparation process)
The preparation step is a step of preparing a concavo-convex layer forming composition containing an aggregate of high-hardness nanoparticles and a binder precursor, an intermediate layer forming composition, a water repellent layer forming composition, and a substrate.
(Substrate)
Since the substrate is the same as the substrate in the antifouling article of the present invention, description thereof is omitted.

(Uneven layer forming composition)
The uneven layer forming composition includes an aggregate of high hardness nanoparticles and a binder precursor.
Since the concavo-convex layer-forming composition contains aggregates of high-hardness nanoparticles, when applied to the surface of the substrate, the particles are likely to be locally stacked, so that the concavo-convex layer is likely to be formed on the resulting coating. Moreover, the intensity | strength of the film | membrane obtained becomes high by including a binder precursor.

The high-hardness nanoparticles and aggregates are the same as the high-hardness nanoparticles and aggregates in the antifouling article described above, and thus the description thereof is omitted.

However, it is preferable that the high-hardness nanoparticles are prepared as a dispersion in which aggregates of high-hardness nanoparticles are dispersed in a dispersion medium, and are blended into the uneven layer forming composition. Examples of the dispersion medium used for the dispersion of the aggregate of high hardness nanoparticles include organic solvents such as water, N-methylpyrrolidone, isopropyl alcohol, N-ethylpyrrolidone, dimethylacetamide, and ethylene glycol. In the present invention, for example, an organic solvent is preferable as a dispersion medium for nanodiamond aggregates, and N-methylpyrrolidone is particularly preferable.

Also, a commercially available product may be used as the dispersion liquid of the aggregates of the high hardness nanoparticles. As a commercial ratio, as a dispersion of nanodiamond aggregate, for example, manufactured by Carbodeon; product grade Hydrogen D in NMP (3.0 mass% N-methylpyrrolidone of nanodiamond aggregate having an average primary particle size of 4 to 6 nm) Dispersion).

The binder precursor is a component that forms the above-described binder by heat treatment, solvent removal treatment, photocuring treatment, or the like. Examples of the binder precursor include an inorganic binder precursor and an organic-inorganic hybrid binder precursor.

As the inorganic binder precursor, a silica precursor is preferable. When the uneven layer forming composition contains a silica precursor, the adhesion between the formed uneven layer and the substrate can be further improved. Examples of the silica precursor include a silane compound having a hydrolyzable group and silicic acid. Examples of the binder precursor other than the silica precursor include metal oxide precursors, for example, metal compounds having a hydrolyzable group. The metal oxide precursor is a component that forms a metal oxide by hydrolysis condensation reaction. One type of binder precursor may be used alone, or two or more types may be used in combination.

Examples of the silica precursor include silicic acid and a silane compound having a hydrolyzable group. As the silica precursor, one having a low alkali metal content is preferable because it improves the adhesion between the uneven layer to be formed and the substrate. For example, desalting in which a part of the alkali metal is removed from the alkali metal salt of silicic acid. Silicic acid or an alkoxysilane compound or a partial hydrolysis condensate thereof is preferred. Examples of the alkali metal salt of silicic acid include sodium silicate, lithium silicate and potassium silicate, and sodium silicate is particularly preferable.

Sodium silicate _is preferred because those molar ratio of SiO ₂ to Na ₂ O indicated by SiO 2 / _Na 2 O is large tends to remove alkali metal ions, the molar ratio of _SiO 2 / Na ₂ O 3 or more Those are particularly preferred.

The method for removing alkali metal ions from the alkali metal salt of silicic acid can be a conventionally known method. For example, an aqueous solution of sodium silicate is stirred together with a strongly acidic cation exchange resin, and sodium ions are ion-exchanged to reduce the ratio of sodium ions to the total solid content in the aqueous solution.

A silane compound having a hydrolyzable group is a compound having 1 to 4 hydrolyzable groups bonded to a silicon atom in one molecule. Examples of the hydrolyzable group include an alkoxy group, an isocyanato group, an acyloxy group, an aminoxy group, a halogen and the like, and an alkoxy group is preferable. Therefore, an alkoxysilane compound is preferable as the silane compound having a hydrolyzable group. Further, the alkoxysilane compound may be a condensate in which at least some of the molecules are hydrolyzed and condensed (hereinafter also referred to as “partially hydrolyzed condensate of alkoxysilane compound”).

The alkoxysilane compound is a compound having 1 to 4 alkoxy groups bonded to a silicon atom in one molecule, and examples thereof include compounds represented by the following general formula (I).
(R ¹ O) _p SiR ² _(4-p) (I)
In the formula, each R ¹ independently represents an alkyl group having 1 to 4 carbon atoms, R ² independently represents an optionally substituted alkyl group having 1 to 10 carbon atoms, p represents an integer of 1 to 4. When a plurality of R ¹ or R ² are present, they may be the same as or different from each other.

R ¹ is an alkyl group having 1 to 4 carbon atoms, and examples thereof include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and t-butyl, and methyl and ethyl are preferable. The alkyl group having 1 to 10 carbon atoms in R ² is linear or branched, and examples thereof include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, hexyl, decyl and the like. R ² is preferably an alkyl group having 1 to 6 carbon atoms. The substituent in R ² is not particularly limited, but epoxy group, glycidoxy group, methacryloyloxy group, acryloyloxy group, isocyanato group, hydroxy group, amino group, phenylamino group, alkylamino group, aminoalkylamino group, ureido Group, mercapto group and the like. The “alkyl group having 1 to 10 carbon atoms” in R ² means that the alkyl group portion excluding the substituent has 1 to 10 carbon atoms.

Examples of the alkoxysilane compounds include tetraalkoxysilane compounds such as tetramethoxysilane and tetraethoxysilane; 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane and the like which are bonded to silicon atoms in one molecule. And alkoxysilane compounds having 3 alkoxy groups, and tetraalkoxysilane compounds are preferred.

In the concavo-convex layer forming composition, the volume ratio in terms of metal oxide between the high hardness nanoparticles and the binder precursor is preferably 30/70 or more because the antifouling property is obtained due to the concavo-convex shape, and is in close contact with the substrate. 70/30 or less is preferable in order to obtain properties. The silica precursor is preferably demineralized silicic acid obtained by removing a part of the alkali metal from the alkali metal salt of silicic acid.

In addition, when the uneven | corrugated layer forming composition contains the partial hydrolysis-condensation product of an alkoxysilane compound, content of the partial hydrolysis-condensation product of an alkoxysilane compound is the conversion amount of a silica.

The uneven layer forming composition may contain water and an acid under the condition that a hydrolysis condensate of the binder precursor is obtained. When the uneven layer forming composition contains water, the hydrolysis condensation reaction proceeds. The amount of water to be contained is preferably 10 to 500 parts by mass, more preferably 50 to 300 parts by mass with respect to 100 parts by mass of the binder precursor. Here, the amount of the binder precursor is an amount in terms of metal oxide.

Acid acts as a catalyst for hydrolysis condensation reaction. The uneven | corrugated layer forming composition can adjust the reaction rate of the hydrolysis condensation of a binder precursor by containing an acid. Examples of the acid include hydrochloric acid, nitric acid, sulfuric acid and the like. The amount of the acid is preferably 0.1 to 5.0 parts by mass, more preferably 0.2 to 3.5 parts by mass with respect to 100 parts by mass of the binder precursor. Here, the amount of the binder precursor is an amount in terms of metal oxide.

The uneven layer forming composition may contain a solvent for the purpose of improving workability. The solvent is preferably a solvent having good dispersibility of the high-hardness nanoparticles and the binder precursor and low reactivity with these components. Specific examples of the solvent include alcohol (methanol, ethanol, 2-propanol, etc.), ester (acetic ester, butyl acetate, etc.), ether (diethylene glycol dimethyl ether, etc.), ketone (methyl ethyl ketone, etc.), water, and the like. The solvent is preferably water or isopropyl alcohol, more preferably isopropyl alcohol, from the viewpoint of good appearance. The solvent may be a single type or a combination of two or more types.

The content of the solvent is not particularly limited, but is preferably 1,000 to 100,000 parts by weight, and 2,000 to 50,000 parts by weight with respect to a total of 100 parts by weight of the high-hardness nanoparticles and the binder precursor. More preferred. When an aggregate of high hardness nanoparticles is used as a dispersion, the dispersion medium of the dispersion is included as part of the solvent. That is, the amount of the solvent in that case is the total amount of the amount of the dispersion medium and the amount of the solvent newly used for the uneven layer forming composition. If the content of the solvent is 1,000 parts by mass or more with respect to a total of 100 parts by mass of the high-hardness nanoparticles and the binder precursor, rapid progress of hydrolysis and condensation reaction can be prevented. If the amount is less than or equal to parts by mass, hydrolysis and condensation reactions proceed. Here, the amount of the binder precursor is an amount in terms of metal oxide.

The concavo-convex layer forming composition can contain further components within a range not impairing the effects of the present invention. Examples of such components include surfactants, antifoaming agents, leveling agents, ultraviolet absorbers, viscosity modifiers, antioxidants, fungicides, and pigments.

The content of the further component in the uneven layer forming composition is not particularly limited, but is preferably 0.02 to 1 part by mass, preferably 0.02 to 1 part by mass with respect to 100 parts by mass in total of the high-hardness nanoparticles and the binder precursor. 0.5 parts by mass is more preferable, and 0.02 to 0.3 parts by mass is particularly preferable. Here, the amount of the binder precursor is an amount in terms of metal oxide.

Examples of the concavo-convex layer forming composition include a nano-diamond aggregate as high-hardness nanoparticles and a silica precursor as a binder precursor at a ratio of 30/70 to 70/30 in volume ratio (where the silica precursor is In terms of silicon oxide), the total content of nanodiamond aggregate and silica precursor with respect to the total amount of the composition is 0.5 to 2.5% by mass, and the solvent is selected from water and isopropyl alcohol (however, In the case where the nanodiamond aggregate is blended in a dispersion, the solvent preferably includes a composition containing a dispersion medium of nanodiamond aggregate). In this case, the nanodiamond aggregate is preferably blended into the composition as an N-methylpyrrolidone dispersion. In that case, the solvent in the composition contains N-methylpyrrolidone.

Further, as the silica precursor in the composition, silicic acid and a silane compound having a hydrolyzable group are preferable, and demineralized silicic acid obtained by removing a part of the alkali metal from the alkali metal salt of silicic acid is particularly preferable.

(Intermediate layer forming composition)
As an intermediate | middle layer forming composition, the composition which does not contain a high hardness nanoparticle in the said uneven | corrugated layer forming composition is mentioned. The intermediate layer forming composition is preferably a composition including a silica precursor such as silicic acid or a silane compound having a hydrolyzable group and a solvent.

(Water repellent layer forming composition)
The water repellent layer-forming composition preferably contains a fluorine-containing hydrolyzable silane compound.
The water repellent layer layer-forming composition may contain a solvent for the purpose of improving workability. The solvent is preferably a solvent having good solubility of the fluorine-containing hydrolyzable silane compound and low reactivity to these components. Examples of the solvent include alcohol (methanol, ethanol, 2-propanol, etc.), hydrofluorocarbon and the like. The solvent may be a single type or a combination of two or more types.

The content of the solvent is not particularly limited, but is preferably 1,000 to 100,000 parts by weight, more preferably 2,000 to 50,000 parts by weight, based on 100 parts by weight of the total of the fluorine-containing hydrolyzable silane compound. preferable. When it is in the above range, sufficient antifouling property can be imparted and the appearance of the resulting film is improved.

Specific examples of the fluorinated hydrolyzable silane compound include compounds represented by the following formula (II) as hydrolyzable silane compounds having a fluorinated alkyl group or a fluorinated alkylene group.
(A-Rf) _r -Si (R ³ ) _v X ³ _(4-rv) (II)
In the formula (II), Rf is a divalent organic group having 1 to 20 carbon atoms including at least one fluoroalkylene group, and A is a fluorine atom or —Si (R ³ ) _v X ³ _(3-v) , R ³ is a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms having no fluorine atom, and X ³ represents a hydrolyzable group. r is 1 or 2, v is 0 or 1, and r + v is 1 or 2. When a plurality of A-Rf and X ³ are present, these may be different from each other or the same.

R ³ is preferably a hydrocarbon group having 1 to 3 carbon atoms, and particularly preferably a methyl group.
In formula (II), it is particularly preferred that r is 1 and v is 0 or 1.
Examples of X ³ include an alkoxy group, a halogen atom, and an acyl group. Hydroxyl group is converted into a hydroxyl group (silanol group), and further, a reaction of condensation reaction between atoms to form a Si—O—Si bond facilitates the smooth progress of the alkoxy group having 1 to 4 carbon atoms and the halogen atom. Preferably, a methoxy group, an ethoxy group, and a chlorine atom are more preferable, and a methoxy group and an ethoxy group are particularly preferable.

Specific examples of the fluorine-containing hydrolyzable silane compound (II) include the following compounds.
F (CF ₂ ) ₄ CH ₂ CH ₂ Si (OCH ₃ ) ₃ ,
F (CF ₂ ) ₄ CH ₂ CH ₂ Si (OC ₂ H ₅ ) ₃ ,
F (CF ₂ ) ₆ CH ₂ CH ₂ Si (OCH ₃ ) ₃ ,
F (CF ₂ ) ₆ CH ₂ CH ₂ Si (OC ₂ H ₅ ) ₃ ,
(CH ₃ O) ₃ SiCH ₂ CH ₂ (CF ₂ ) ₆ CH ₂ CH ₂ Si (OCH ₃ ) ₃ ,
_{_{_{_{CF 3 O (CF 2 CF 2}}}} O) 7 CF 2 C (O) NHCH 2 CH 2 CH 2 Si (OCH 3) 3,
_{_{_{_{CF 3 CF 2 O (CF 2}}}} ) O (CF 2 CF 2 CF 2 CF 2 OCF 2 CF 2 O) 7 CF 2 CF 2 CF 2 C (O) NHCH 2 CH 2 CH 2 Si (OCH 3) 3,
_{_{_{_{CF 3 CF 2 O (CF 2}}}} ) O (CF 2 CF 2 CF 2 CF 2 OCF 2 CF 2 O) 13 CF 2 CF 2 CF 2 C (O) NHCH 2 CH 2 CH 2 Si (OCH 3) 3,
F (CF ₂ ) ₆ CH ₂ CH ₂ SiCl ₃ ,

Among these, a compound having no ether group is preferable because it is excellent in light resistance. F (CF ₂ ) ₄ CH ₂ CH ₂ Si (OC ₂ H ₅ ) ₃ is particularly preferable in that the compound itself is less deteriorated.

These may be used individually by 1 type, and may be used in combination of 2 or more type. The content of the fluorine-containing hydrolyzable silane compound in the water-repellent layer forming composition is appropriately adjusted according to the type and combination of the fluorine-containing hydrolyzable silane compound used.

When the water-repellent layer-forming composition contains a fluorine-containing hydrolyzable silane compound, it may contain water and an acid under the condition that the hydrolysis condensate is obtained. Examples of the acid include hydrochloric acid, nitric acid, sulfuric acid and the like.

(Uneven layer forming process)
The concavo-convex layer forming step includes a step of coating the concavo-convex layer forming composition on the substrate to form the concavo-convex layer forming composition layer, and a step of heating the concavo-convex layer forming composition layer to form the concavo-convex layer. Including.

(Application of uneven layer forming composition)
The uneven layer forming composition can be applied by various wet coating methods. Examples of the wet coating method include spin coating, dip coating, spray coating, flow coating, curtain flow coating, die coating, and squeegee coating, and spin coating is preferable.

The uneven layer forming composition is preferably applied to at least a part of the surface of the substrate and applied to the entire surface of at least one main surface of the substrate. The thickness of the concavo-convex layer forming composition layer is not particularly limited as long as it is an amount that provides a desired concavo-convex layer. Further, the amount of the concavo-convex layer forming composition applied on the substrate is not particularly limited as long as a desired concavo-convex layer is obtained, and the solid content is set to 1.6 to 1,600 g / m ^2. It is preferably 8.0 to 800 g / m ² . In the present invention, the content of the component in terms of solid content refers to the mass of the residue excluding volatile components such as water.

(Curing the uneven layer forming composition)
The formed uneven layer forming composition layer becomes an uneven layer by curing. Curing is accelerated by heating. The binder precursor may react with the high hardness nanoparticles by heating. When the concavo-convex layer forming composition contains an aggregate of high-hardness nanoparticles and silicic acid or an alkoxysilane compound, the silicic acid or alkoxysilane compound is hydrolyzed and condensed to obtain a silica binder. In this case, at least a part of the silicic acid or the alkoxysilane compound may hydrolyze and condense with silanol groups present on the surface of the aggregate of high-hardness nanoparticles.

When the uneven layer forming composition layer is cured by heating, the heating can be performed by any heating means such as an electric furnace, a gas furnace, or an infrared heating furnace. The treatment temperature is preferably 20 to 700 ° C, more preferably 80 to 500 ° C, and particularly preferably 100 to 400 ° C. When the treatment temperature is 20 ° C. or higher, the adhesion between the substrate and the concavo-convex layer is further improved, and when it is 700 ° C. or less, deterioration of the substrate due to heat is suppressed and the productivity is excellent. The treatment time varies depending on the treatment temperature, but is preferably 1 to 180 minutes, more preferably 5 to 120 minutes, and particularly preferably 10 to 60 minutes. When the heat treatment time is 1 minute or longer, the adhesion between the substrate and the concavo-convex layer is further improved, and when it is 180 minutes or shorter, deterioration of the substrate due to heat is suppressed and the productivity is excellent.

(Intermediate layer forming process)
As a method of forming the intermediate layer, the intermediate layer forming composition is applied on the concavo-convex layer obtained in the above-described step and cured. Examples of the coating method include spin coating, dip coating, spray coating, flow coating, curtain flow coating, die coating, and squeegee coating, and spin coating is preferred.

If necessary, excess liquid may be removed. By removing the excess liquid, the film thickness of the intermediate layer is made uniform, so that an antifouling layer reflecting the shape of the uneven layer can be obtained. The excess liquid may be removed after the following curing process, may be performed before the curing process, or may be performed during the curing process.

The intermediate layer forming composition applied on the uneven layer is cured to form an intermediate layer on the uneven layer. Curing of the intermediate layer forming composition is accelerated by heating or humidification.

Heating can be performed by any heating means such as an electric furnace, a gas furnace or an infrared heating furnace. The treatment temperature is preferably 20 to 200 ° C, more preferably 50 to 180 ° C, and more preferably 80 to 150 ° C. In particular, when not humidified, the treatment temperature is preferably 50 ° C. or higher, more preferably 80 ° C. or higher.

Humidification can be performed by any humidifying means such as a constant temperature and high humidity tank. For humidification, when the temperature is 20 to 50 ° C., the humidity is preferably 50 to 95% RH.

The curing treatment time is preferably 1 to 60 minutes, and more preferably 10 to 20 minutes. When the curing time is 1 minute or longer, the adhesion between the uneven layer and the intermediate layer is further improved, and when it is 60 minutes or shorter, the productivity is excellent. In addition, you may perform the hardening process of an intermediate | middle layer forming composition simultaneously with the hardening process of the following water repellent layer forming compositions.

(Water repellent layer forming process)
The water-repellent layer is formed by applying a water-repellent layer-forming composition on the intermediate layer obtained in the above-described step and curing it. If necessary, excess liquid may be removed. By removing the excess liquid, the film thickness of the water-repellent layer is made uniform, so that an antifouling layer reflecting the shape of the uneven layer / intermediate layer can be obtained. The excess liquid may be removed after the following curing process, may be performed before the curing process, or may be performed during the curing process.

The water repellent layer forming composition applied on the intermediate layer is cured to obtain an antifouling layer. Curing of the water repellent layer forming composition is accelerated by heating or humidification.

The curing treatment time is preferably 1 to 60 minutes, and more preferably 10 to 20 minutes. When the curing treatment time is 1 minute or longer, the adhesion between the intermediate layer and the water repellent layer is further improved, and when it is 60 minutes or shorter, the productivity is excellent.

<Use of antifouling article>
The antifouling article includes window glass (for example, window glass for transportation equipment such as automobiles, railroads, ships, airplanes), walls (for example, partitions, road walls, etc.), refrigerated showcases, mirrors (for example, vanity tables) Mirrors, bathroom mirrors, etc.), optical instruments, tiles, toilets, bathtubs, bathroom walls, vanity tables, curtain walls, aluminum sashes, faucet fittings, building boards, lenses, cover glasses, condensing mirrors It is done.

Examples of the cover glass include a solar cell, a condensing lens, and a condensing mirror cover glass. A condensing lens or a condensing mirror is used for a concentrating solar power generation device or a concentrating solar power generation device, for example.

This antifouling article is particularly suitable for outdoor use in areas with little rain, such as deserts.
Since this antifouling article is excellent in wear resistance, it is also suitable as a window glass for automobiles and the like.

Hereinafter, the present invention will be described in detail by way of examples. The present invention is not limited to these examples. Examples 2, 3, 5, and 6 described below are examples, and examples 1, 4, and 7 to 9 are comparative examples.

<Adjustment of antifouling articles>
[Example 1]
While stirring 237.5 g of distilled water, sodium silicate No. 4 (manufactured by Nippon Chemical Industry Co., Ltd., (SiO ₂ : 24.0% by mass, Na ₂ O: 7.0% by mass. SiO ₂ / Na ₂ O 62.5 g of a molar ratio of 3.5 / 1) and 180 g of a cation exchange resin (Diaion SK1BH, manufactured by Mitsubishi Chemical Corporation) were added and stirred for 10 minutes or more, and then the cation exchange resin was separated by suction filtration. Then, a desalted sodium silicate solution having a solid content concentration of 5% by mass in terms of silicon oxide was obtained.

While stirring 5.53 g of 2-propanol, a nanodiamond dispersion (Carbodeon: HydrogenD in NMP: (3.0% by mass N− of nanodiamond aggregate having an average primary particle size of 4 to 6 nm) Methylpyrrolidone dispersion) (63.84 g) and the above-mentioned desalted sodium silicate solution in the order of 0.58 g, the total solid content of nanodiamond and binder precursor is 1.5 mass%, nanodiamond and binder precursor A concave-convex layer forming composition (A1) having a volume ratio of 80/20 to the solid content in terms of silicon oxide was prepared.Hereinafter, the volume of the binder precursor when referring to the volume ratio of the particles to the binder precursor is oxidation. It is the volume of solid content in terms of silicon.

Set a glass plate (sodium lime glass manufactured by Asahi Glass) with a length of 100 mm, width of 100 mm, and thickness of 3.5 mm on a spin coater, and drop coat 2.0 g of the uneven layer forming composition (A1) onto the surface of the glass plate. After that, heat treatment was performed at 200 ° C. for 30 minutes to obtain an antifouling article having the same cross section as shown in FIG. 1 having only the uneven layer as the antifouling layer. The volume ratio of nanodiamond and binder in the resulting uneven layer is 80/20. In addition, it can be said that the volume ratio of the nanodiamond particles and the binder in the uneven layer is the same as the volume ratio of the nanodiamond particles and the binder precursor. In each of the following examples, the volume ratio of the particles such as nanodiamond and the binder precursor is described in the “Volume ratio between particles and binder” column of Table 1.

[Examples 2 to 4]
As in Example 1, except that the volume ratio of nanodiamond and binder precursor (nanodiamond / binder precursor) was adjusted as shown in the volume ratio of particles to binder (particle / binder) in Table 1, Layer forming compositions A2 to A4 were prepared. Subsequently, using the antifouling layer forming compositions A2 to A4, an antifouling article having only an uneven layer as an antifouling layer was produced in the same manner as in Example 1. Table 1 shows the volume ratio of nanodiamond and binder in the uneven layer obtained in each example. Moreover, the scanning electron micrograph (800,000 times) of the antifouling layer surface of the antifouling article obtained in Example 2 is shown in FIG.

[Example 5]
Tetraisocyanatosilane (manufactured by Matsumoto Fine Chemical Co., Ltd.) was diluted with butyl acetate (manufactured by Junsei Kagaku Co., Ltd.) to 5% by mass to obtain an intermediate layer forming composition (B1).

In addition, while stirring 14.49 g of 2-propanol, tridecafluorooctyltrimethoxysilane (F (CF ₂ ) ₆ CH ₂ CH ₂ Si (OCH ₃ ) ₃ ; Momentive Performance Materials Japan Joint After adding 0.51 g of TSL8257) and 0.15 g of 1% by mass nitric acid aqueous solution in this order, the mixture was stirred at 25 ° C. for 180 minutes to form a water repellent layer having a solid content concentration of 3% by mass. A precursor (1) was obtained.

While stirring 13.75 g of hydrofluorocarbon (Asahi Glass AC-6000 (trade name) manufactured by Asahi Glass Co., Ltd.), 1.25 g of the water-repellent layer forming precursor (1) was added in this order to obtain a solid. A water repellent layer-forming composition (C1) having a partial concentration of 0.25% by mass was prepared.

Next, in the same manner as in Example 1, the glass plate on which the uneven layer was formed was set on a spin coater, and 4.0 g of the intermediate layer forming composition (B1) was dropped on the surface of the uneven layer and spin-coated. Next, 4.0 g of the water repellent layer-forming composition (C1) was dropped on the surface of the formed intermediate layer (uncured) and spin-coated, and then the temperature was increased in a high-temperature and high-humidity tank set at 20 ° C. and 50 RH%. After holding for a minute, denatured alcohol is dropped on the surface, and excess components are removed using a spin coater, so that an uneven layer, an intermediate layer (film thickness: 1 nm), and a water repellent layer (film thickness) are sequentially formed from the glass plate side. An antifouling article having a cross section similar to that shown in FIG.

[Example 6]
In the same manner as in Example 5 except that no intermediate layer was formed in Example 5, an antifouling article having an uneven layer and a water-repellent layer in order from the glass plate side as an antifouling layer was produced.

[Example 7]
While stirring 6.58 g of 2-propanol, a dispersion of a pearl necklace-like silica aggregate (a long and narrow silica aggregate in which a plurality of spherical particles are linked together to form a secondary aggregate) (manufactured by Nissan Chemical Co., Ltd., Snow (Text PS-SO: average primary particle diameter 15 nm, average secondary particle diameter 88 nm) 1.19 g, 2.18 g of the above-mentioned desalted sodium silicate solution were added in this order, and the solid content in terms of silicon oxide was 2.95% by mass, pearl The uneven | corrugated layer forming composition (A5) whose volume ratio of the necklace-like silica aggregate and the silicon oxide conversion solid content of a binder precursor is 57/43 was prepared.

An antifouling article was produced in the same manner as in Example 1 except that the uneven layer forming composition was changed to the uneven layer forming composition (A5).

[Example 8]
While stirring 1.85 g of 2-propanol, a nanodiamond dispersion (Carbodeon: HydrogenD in NMP (3.0 mass% N-methyl of nanodiamond aggregate having an average primary particle size of 4 to 6 nm) was added thereto. 5.59 g of pyrrolidone dispersion) and 2.53 g of the above-mentioned desalted sodium silicate solution were added in order, the total solid content of nanodiamond and binder precursor was 2.95% by mass, oxidation of nanodiamond and binder precursor The uneven | corrugated layer forming composition (A6) whose silicon conversion solid content volume ratio is 57/43 was prepared.

An antifouling article was produced in the same manner as in Example 1 except that the uneven layer forming composition was changed to the uneven layer forming composition (A6).

[Example 9]
The glass plate not coated with the antifouling composition was evaluated as it was.

<Evaluation of antifouling articles>
The evaluation of the antifouling article in each example was performed as follows.
In addition, below, the haze value was measured with C light source using the haze measuring apparatus (the Big Gardner company make, haze guard plus).

(Appearance evaluation)
The appearance of the antifouling article was visually observed and evaluated according to the following criteria.
“A”: no foreign matter or defect having a diameter of 1 mm or more is observed.
“B”: Foreign matter having a diameter of 1 mm or more and defects of 1 or more and 5 or less.
“C”; foreign matter having a diameter of 1 mm or more, and more than 5 defects.

(Surface roughness (Ra))
It measured using the scanning probe microscope (SII nanotechnology company make, SPA400). The setting conditions of the microscope were: cantilever: SI-DF40 (with rear surface AL), number of XY data: 256 points, scanning area: 10 μm × 10 μm.

(Vertical distance (average value), convex part coverage)
The surface of the antifouling layer was observed with a scanning electron microscope (manufactured by Hitachi, Ltd., S-4800), and 1 μm × 1 μm randomly extracted from the obtained image by image conversion software (image J). With reference to the protrusion having the maximum height from the substrate surface in the range, the protrusion T having a height of 90% or more is identified, and the distance between the vertices (average value) of the protrusion T and the total area of the measurement region is identified. The ratio (protrusion coverage) of the total area of the bottom surface of the protrusion T was calculated.

(Dirt adhesion)
A 5 cm × 5 cm test piece was cut out from the antifouling article, and the evaluation mixed powder (2.3% by mass of carbon black 1 (particle diameter) was placed on the surface of the antifouling layer with the main surface of the antifouling article horizontal. 0.002 to 0.028 μm), 9.3% by mass of carbon black 2 (12 kinds of JIS test powder 1), 62.8% by mass of yellow ocher (natural ocher for pigments), 20.9% by mass Baked Kanto loam (8 kinds of JIS test powder 1) and 4.7% by mass of silica powder (3 kinds of JIS test powder 1)) of 0.02 g / cm ² Sprinkle at a rate of 10 and leave for 10 seconds. Next, an aluminum test plate was used, and the antifouling article was tilted so that the angle formed by the main surface of the test plate and the surface of the test plate was 135 ° from the height of 3 cm above the test plate to 10 cm. The haze value is measured after removing the evaluation mixed powder by repeating the operation of moving the antifouling article at a speed of / sec until the lower end of the antifouling article contacts the surface of the test plate twice. The haze value is measured five times, and the average is taken as the haze value after the test, and the value obtained by subtracting the haze value before the test from the haze value after the test is taken as the antifouling index ΔHx. Table 1 shows the initial ΔHx as ΔHxi.

(Water contact angle CA)
A 1 μL water droplet was placed on the surface of the antifouling layer, and the contact angle was measured with a contact angle measuring device (DM-701, manufactured by Kyowa Interface Science Co., Ltd.). Measurements were made at three different points, and the average value was calculated.

(Martens hardness)
Measure Martens hardness (unit: MPa) using indentation test equipment (Fischer, Picodenter HM500) with indentation load of 0.03 mN, holding time of 5 seconds, loading speed and unloading speed of 0.05 mN / 5 seconds. did. The average value was obtained by measuring three times.

(Abrasion resistance test 1)
For Examples 1 to 3 and Examples 7 to 8, a reciprocating traverse tester (manufactured by KT Corporation) was attached with a cotton cloth according to JIS L0803, and a load of 1.23 × 10 ⁴ N / m ² using a 700 g weight. And the antifouling article was washed with water.
The appearance of the antifouling article after rubbing and washing with water was visually observed and evaluated according to the following criteria.
“A”: No scratch of 50 mm or more in length was observed.
“B”: 1 to 5 scratches having a length of 50 mm or more are observed. “C]; more than 5 scratches having a length of 50 mm or more.
“D”: The film peels off.
Further, the above-mentioned dirt adhesion test was performed on the surface after friction, and the change in haze value (ΔHxr1) after friction was obtained.

(Abrasion resistance test 2)
About Example 5 and Example 6, a cotton cloth compliant with JIS L0803 was attached to a reciprocating traverse tester (manufactured by KT Corporation), a load of 2.95 × 10 ⁴ N / m ² was applied using a 1.2 kg weight, and 500 After the reciprocating friction, the antifouling article was washed with water.
The appearance of the antifouling article after rubbing and washing with water was visually observed and evaluated according to the same evaluation criteria as described above.

Further, the above-mentioned dirt adhesion test was performed on the surface after friction, and the change in haze value (ΔHxr2) after friction was obtained. Note that the antifouling article having ΔHxr2 of 12% or less also has a result of 12% or less for ΔHxr1.
The results are shown in Table 1. In Table 1, a blank indicates that evaluation has not been performed.

It can be seen that the antifouling article of this example has a good appearance and excellent wear resistance and antifouling properties. In Comparative Examples 1, 4, and 7, the wear resistance was not sufficient. Further, Comparative Example 8 had a problem in appearance at the initial stage and did not reach a practical level.

DESCRIPTION OF

SYMBOLS

1A, 1B ... Antifouling | stain-proof article, 2 ... Base | substrate, 3 ... High-hardness nanoparticle, 4 ... Binder, 5 ... Uneven layer, 6 ... Antifouling layer, 7 ... Intermediate | middle layer, 8 ... Water-repellent layer, 9 ... Protrusion 10 ... recess

Claims

An antifouling article comprising a substrate and an antifouling layer disposed on the substrate and having a plurality of protrusions including a concavo-convex layer containing an aggregate of high hardness nanoparticles and a binder on the surface,
After placing a cotton cloth specified in JIS L0803 on the surface of the antifouling layer, applying a pressure of 1.23 × 10 4 N / m 2 and reciprocating 100 times, and then washing the antifouling article with water, An antifouling article having an antifouling index ΔHx measured by the following method of 12% or less.
(Measurement method of antifouling index ΔHx)
With the main surface of the antifouling article horizontal, the mixed powder for evaluation (2.3% by mass of carbon black 1 (particle size 0.002 to 0.028 μm), 9.3% by mass on the surface of the antifouling layer) % Carbon black 2 (12 types of JIS test powder 1), 62.8% by mass of yellow ocher (natural ocher for pigments), 20.9% by mass of calcined Kanto loam (8 of JIS test powder 1) Seed) and 4.7% by mass of silica powder (mixed powder of three kinds of JIS test powder 1) are sprayed at a rate of 0.02 g / cm 2 and allowed to stand for 10 seconds. Next, an aluminum test plate was used, and the antifouling article was tilted so that the angle formed by the main surface of the test plate and the surface of the test plate was 135 ° from the height of 3 cm above the test plate. The haze value is measured after removing the evaluation mixed powder by repeating twice the operation of moving the lower end of the antifouling article to the surface of the test plate at a speed of / sec. The haze value measurement is carried out five times, and the average is taken as the haze value after the test, and the value obtained by subtracting the haze value before the test from the haze value after the test is taken as the antifouling index ΔHx.
The antifouling article according to claim 1, wherein the high-hardness nanoparticles have a Mohs hardness of 12 or more.
The antifouling article according to claim 1 or 2, wherein the antifouling layer has a surface Ra of 2 to 6 nm.
The antifouling article according to any one of claims 1 to 3, wherein the high-hardness nanoparticles have an average primary particle diameter of 1 to 50 nm.
Among the protrusions, with respect to the protrusion T having a height of 90% or more with reference to the protrusion having the maximum height from the surface on which the antifouling layer of the base is disposed, The average value of the distance between vertices is 50 to 1,000 nm,
The antifouling article according to any one of claims 1 to 4, wherein the ratio of the total area of the bottom surface of the protrusion T to the area of the substrate on which the antifouling layer is disposed is 12 to 70%.
The antifouling article according to any one of claims 1 to 5, wherein a volume ratio of the high-hardness nanoparticles and the binder is 30/70 to 70/30.
The antifouling article according to any one of claims 1 to 6, wherein the antifouling layer further has a water repellent layer on the uneven layer.
The antifouling article according to claim 7, wherein the antifouling layer further comprises an intermediate layer between the uneven layer and the water repellent layer.
The antifouling article according to any one of claims 1 to 8, wherein the antifouling layer has a surface Martens hardness of 1000 MPa or more.