JP2015075711A - Silica particle-containing fine concavo-convex structural body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silica particle-containing fine concavo-convex structural body having uniform thickness as well as good hardness and scratch resistance.SOLUTION: A silica particle-containing fine concavo-convex structural body having a fine concavo-convex structure satisfies conditions (1) through (3) below. (1) The structural body has a plurality of protrusions 13 on a surface thereof, the protrusions having a pitch w1 of 50-400 nm. (2) The structural body is a cured product of a curable composition containing surface-processed fine silica particles (a), a polymerizable component, and a polymerization initiator, where the surface-processed fine silica particles (a) are obtained by surface-processing unprocessed fine silica particles (a0) having a number average particle diameter of no less than 30 nm using a specific silane compound (e) and another specific silane compound (f). (3) The unprocessed fine silica particles (a0) have a number average particle diameter that is 50-300% of a protrusion pitch w1.

Description

  The present invention relates to a fine concavo-convex structure containing silica particles.

  At interfaces (surfaces) that come into contact with air, such as various displays, lenses, and show windows, there is a problem of reduced visibility due to reflection of sunlight, illumination, and the like on the surface. As a method for reducing reflection, there is known a method in which several layers of films having different refractive indexes are laminated so that reflected light on the film surface and reflected light on the interface between the film and the substrate cancel each other due to interference. It has been. These films are usually produced by methods such as sputtering, vapor deposition, and coating. However, in such a method, even if the number of laminated films is increased, there is a limit to the decrease in the reflectance and the wavelength dependency of the reflectance. Further, in order to reduce the number of stacked layers in order to reduce the manufacturing cost, a material having a lower refractive index has been demanded.

  In order to lower the refractive index of the material, it is effective to introduce air into the material by some method. As one method for lowering the refractive index of the film surface, for example, a method of forming a fine relief structure on the film surface is widely known. According to this method, since the refractive index of the entire surface layer on which the fine concavo-convex structure is formed is determined by the volume ratio between air and the material forming the fine concavo-convex structure, the refractive index can be significantly reduced. become. As a result, the reflectance can be reduced even when the number of stacked layers is small.

  In addition, an antireflection film in which convex portions of conical fine protrusions are continuously formed on the entire film in an antireflection film formed on a glass substrate has been proposed (see, for example, Patent Document 1). As described in Patent Document 1, the antireflection film in which the cone-shaped convex portion (fine concavo-convex structure) is formed has a continuously changing cross-sectional area when cut in the film surface direction, and the substrate from the air side. Since the refractive index gradually increases toward the side, it becomes an effective antireflection means. The antireflection film exhibits excellent optical performance that cannot be replaced by other methods. Further, since the fine protrusions are composed of particles having a diameter in terms of a sphere of 10 to 50 nm and a resin, the durability is also excellent.

  Since the antireflection film having the fine concavo-convex structure as described above is used at the interface in contact with air, it is preferable to have sufficient hardness and scratch resistance.

JP 2009-20355 A

However, as described in Patent Document 1, if the fine protrusions on the surface layer of the antireflection film are made of particles and resin, the hardness and scratch resistance may be inferior because the cured product becomes brittle while being excellent in flexibility and wear. There was a problem that there was.
Accordingly, an object of the present invention is to provide a finely textured structure containing silica particles having an antireflection function and excellent in hardness.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have surface-treated silica fine particles having a specific number average particle diameter, and appropriately adjusted the pitch of the convex portions of the silica particle-containing fine concavo-convex structure. It has been found that the above problem can be solved.

（式（１）中、Ｒ^１は水素原子またはメチル基を表し、Ｒ^２は水素原子またはフェニル基または炭素数１〜４のアルキル基を表し、Ｒ^３は水素原子またはフェニル基または炭素数１〜１０の炭化水素基を表し、ａは１〜１６の整数であり、ｂは０〜３の整数である。なお、ｂが２以上である場合には、複数のＲ^２は同一でも異なっていてもよく、ｂが１以下の場合には、複数存在するＲ^３は同一でも異なっていてもよい。）

（式（２）中、Ｒ^４は炭素数１〜３のアルキル基またはフェニル基を表し、Ｒ^５は水素原子または炭素数１〜１０の炭化水素基を表し、ｃは０〜６の整数であり、ｄは０〜２の整数である。）。
［２］前記表面処理前のシリカ微粒子（ａ０）の数平均粒子径が１５０〜５５０ｎｍ、前記凸部のピッチが１００〜２５０ｎｍである、［１］に記載のシリカ粒子含有微細凹凸構造体
［３］前記硬化性組成物が、前記表面処理前のシリカ微粒子（ａ０）１００質量部に対し、前記重合性成分として、３官能以上の多官能（メタ）アクリレート（Ａ）を１０〜２５０質量部、２官能の多官能（メタ）アクリレート（Ｂ）を１０〜２００質量部を含むことを特徴とする、［１］または［２］に記載シリカ粒子含有微細凹凸構造体。
［４］前記表面処理前のシリカ微粒子（ａ０）の割合が、シリカ粒子含有微細凹凸構造体の総質量に対し、２０〜４５質量％である、［１］〜［３］のいずれか一項に記載のシリカ粒子含有微細凹凸構造体。 The present invention has the following aspects.
[1] A silica particle-containing fine concavo-convex structure having a fine concavo-convex structure on the surface, which satisfies the following conditions 1 to 3.
1) The surface has a plurality of convex portions, and the pitch of the convex portions is 50 to 400 nm. 2) Curing containing surface-treated silica fine particles (a), a polymerizable component, and a polymerization initiator. The composition is cured,
The surface-treated silica fine particles (a) are silica fine particles (a0) having a number average particle diameter of 30 nm or more before surface treatment, and the silane compound (e) represented by the following general formula (1) and the following general formula ( 2) It is obtained by surface treatment with the silane compound (f) represented by 3) 3) The number average particle diameter of the silica fine particles (a0) before the surface treatment is 50 to 300 of the pitch of the convex portions. %.

(In Formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom, a phenyl group, or an alkyl group having 1 to 4 carbon atoms, and R ³ represents a hydrogen atom, a phenyl group, or 1 carbon atom. Represents a hydrocarbon group of 10 to 10, a is an integer of 1 to 16, and b is an integer of 0 to 3. When b is 2 or more, a plurality of R ² may be the same or different. And when b is 1 or less, a plurality of R ³ may be the same or different.)

(In the formula (2), ^{R 4} represents an alkyl group or a phenyl group having 1 to 3 carbon atoms, ^{R 5} represents a hydrocarbon group having 1 to 10 carbon hydrogen atom or a C, c is an integer from 0 to 6 And d is an integer from 0 to 2).
[2] The silica particle-containing fine uneven structure [3] according to [1], wherein the number average particle diameter of the silica fine particles (a0) before the surface treatment is 150 to 550 nm, and the pitch of the protrusions is 100 to 250 nm. The curable composition has 10 to 250 parts by mass of a trifunctional or higher polyfunctional (meth) acrylate (A) as the polymerizable component with respect to 100 parts by mass of the silica fine particles (a0) before the surface treatment. The silica particle-containing fine concavo-convex structure according to [1] or [2], comprising 10 to 200 parts by mass of a bifunctional polyfunctional (meth) acrylate (B).
[4] Any one of [1] to [3], wherein the ratio of the silica fine particles (a0) before the surface treatment is 20 to 45% by mass with respect to the total mass of the silica particle-containing fine uneven structure. The fine concavo-convex structure containing silica particles as described in 1.

  According to the present invention, a silica particle-containing fine concavo-convex structure excellent in hardness and scratch resistance can be obtained.

It is typical sectional drawing which shows an example of a structure of the laminated body containing the silica particle containing fine concavo-convex structure of this invention. It is typical sectional drawing which shows an example of a structure of the laminated body containing the silica particle containing fine concavo-convex structure of this invention.

  Hereinafter, the present invention will be described in detail.

The present invention uses silica particles containing fine particles having a specific number average particle diameter, which is obtained by surface-treating and finely adjusting the pitch of the convex portions of the silica particle-containing fine uneven structure. The present invention relates to an uneven structure. Thereby, the hardness and scratch resistance of the fine concavo-convex structure containing silica particles are improved.
That is, the present invention relates to a silica particle-containing fine concavo-convex structure having a fine concavo-convex structure on the surface, which satisfies the following conditions 1 to 3.
1) The surface has a plurality of convex portions, and the pitch of the convex portions is 50 to 400 nm. 2) Curing containing surface-treated silica fine particles (a), a polymerizable component, and a polymerization initiator. The composition is cured,
The surface-treated silica fine particles (a) are subjected to surface treatment with specific silane compounds (e) and specific silane compounds (f) before the surface treatment of silica fine particles (a0) having a number average particle diameter of 30 nm or more. 3) The number average particle diameter of the silica fine particles (a0) before the surface treatment is 50 to 300% of the pitch of the convex portions.

≪Curable composition≫
The curable composition includes surface-treated silica fine particles (a) (hereinafter also referred to as “silica fine particles (a)”), a polymerizable component, and a polymerization initiator.

<Silica fine particles (a)>
The silica fine particles (a) used in the present invention are prepared by subjecting the silica fine particles (a0) (hereinafter also referred to as “silica fine particles (a0)”) to be surface-treated with the silane compound (e) and the silane compound (f). It is obtained by doing.
(Silica fine particles (a0))
In the curable composition, the number average particle diameter of the silica fine particles (a0) before the surface treatment is 30 nm or more, preferably 50 to 550 nm, more preferably 150 to 550 nm, and still more preferably 150 to 250 nm. By setting the number average particle diameter of the silica fine particles (a0) before the surface treatment to 30 nm or more, sufficient strength is given to the cured product, and the convex portions are given flexibility by preventing particles from entering the convex portions.
The number average particle diameter of the silica fine particles (a0) before the surface treatment is 50 to 300% of the pitch of the convex portions, preferably 80 to 300%, more preferably 100 to 150% of the pitch of the convex portions. is there. Since the number average particle diameter of the silica fine particles (a0) before the surface treatment is 50% or more of the pitch of the convex portions, the intrusion of the silica fine particles (a) into the convex portions of the fine concavo-convex structure is suppressed. By imparting flexibility to the part, the convex part does not become brittle, and the scratch resistance of the silica particle-containing fine concavo-convex structure is improved. In addition, since the number average particle diameter of the silica fine particles (a0) before the surface treatment is 100% or more of the pitch of the convex portions, the intrusion of the particles into the convex portions is further suppressed, so that the convex portions have flexibility. By imparting, the convex portion does not become brittle, and the scratch resistance of the silica particle-containing fine uneven structure is further improved. By making the number average particle diameter of the silica fine particles (a0) before the surface treatment 300% or less of the pitch of the convex portions, the dispersibility in the composition of the silica fine particles (a) and the fine concavo-convex structure containing silica particles after curing The light transmittance of the body is improved.
In this specification, “pitch” means the distance from the tip of a convex portion to the tip of an adjacent convex portion.

The number average particle diameter of the silica fine particles (a0) is obtained, for example, as follows:
The silica fine particles (a0) are observed with a high-resolution transmission electron microscope (H-9000 type, manufactured by Hitachi, Ltd.). 100 silica particle images are arbitrarily selected from the observed fine particle images, and the average particle size is obtained as their number average particle size by a known image data statistical processing technique.

  In the present invention, silica fine particles having different number average particle diameters may be mixed and used to increase the filling amount of the silica fine particles (a) in the silica particle-containing fine uneven structure. Further, as the silica fine particles (a), porous silica sol, or a composite metal oxide of aluminum, magnesium, zinc or the like and silicon may be used.

The ratio of the silica fine particles (a0) before the surface treatment in the curable composition is preferably 10 to 80% by mass with respect to the total mass (excluding the diluting solvent) of the curable composition. From the viewpoint of the balance between the heat resistance of the concavo-convex structure and the viscosity of the curable composition, it is more preferably 20 to 45% by mass. Within this range, the fluidity of the curable composition and the dispersibility of the silica fine particles (a) in the curable composition are good. Therefore, if such a curable composition is used, sufficient strength and heat resistance can be obtained. It is possible to easily produce a silica particle-containing fine concavo-convex structure having properties.
The “ratio of silica fine particles (a0) before surface treatment in the curable composition” means the surface of the silane compound (e) and the silane compound (f) in the silica fine particles (a) in the curable composition. It means the ratio of silica fine particles (a0) excluding the amount treated.

  As the silica fine particles (a0), it is preferable to use silica fine particles (a0) dispersed in an organic solvent (hereinafter also referred to as “colloidal silica”) from the viewpoint of dispersibility in the curable composition. As the organic solvent, it is preferable to use a solvent in which an organic component (such as a polymerizable component described later) contained in the curable composition is dissolved.

  Examples of the organic solvent include alcohols, ketones, esters, and glycol ethers. From the easiness of solvent removal in the solvent removal step described later, that is, the step of removing the organic solvent from the mixed solution containing the silica fine particles (a) and the polymerizable component, methanol, ethanol, isopropyl alcohol, butyl alcohol, n- Alcohol organic solvents such as propyl alcohol and ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone are preferred.

  Among these, isopropyl alcohol is particularly preferable. When silica fine particles (a0) before surface treatment dispersed in isopropyl alcohol are used, the viscosity of the desolvated curable composition is lower than when other solvents are used, and the curable composition has a low viscosity. An object can be produced stably.

  Silica fine particles dispersed in such an organic solvent can be produced by a conventionally known method, and are commercially available, for example, under the trade name IPA-ST (manufactured by Nissan Chemical Co., Ltd.).

(Silane compound (e))
The silane compound (e) is a compound represented by the following general formula (1).

In the formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom, a phenyl group or an alkyl group having 1 to 4 carbon atoms, and R ³ represents a hydrogen atom, a phenyl group or 1 to carbon atoms. 10 represents a hydrocarbon group, a is an integer of 1 to 16, and b is an integer of 0 to 3. In addition, when b is 2 or more, a plurality of R ² may be the same or different, and when b is 1 or less, a plurality of R ³ may be the same or different.

R ² represents a hydrogen atom, a phenyl group or an alkyl group having 1 to 4 carbon atoms, and is preferably a methyl group or an ethyl group from the viewpoints of storage stability and handling properties of the silane compound, and facilitates the synthesis of the silane compound. To a methyl group.
A substituent may be bonded to the phenyl group as long as the effects of the present invention are not impaired.

R ³ represents a hydrogen atom, a phenyl group, or a hydrocarbon group having 1 to 10 carbon atoms (eg, an alkyl group). From the viewpoint of storage stability and handling properties of the silane compound and the ease of synthesis of the silane compound, R ³ Is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a methyl group or an ethyl group.

  a is an integer of 1 to 16, preferably 8 to 16, and more preferably 8 to 10.

  b is an integer of 0 to 3, preferably 0.

  The silane compound (e) reduces the viscosity of the curable composition and improves the dispersion stability of the silica fine particles (a) in the curable composition by reacting with the polymerizable component described later, and curing. It is used in order to reduce curing shrinkage when curing the adhesive composition and to impart molding processability to the cured product. That is, when the silica fine particles (a0) are not surface-treated with the silane compound (e), the viscosity of the curable composition increases, the curing shrinkage during curing increases, the cured product becomes brittle, and the cured product becomes Since cracks are generated, it is not preferable.

  Examples of the silane compound (e) include γ-acryloxypropyldimethylmethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-acryloxypropyldiethylmethoxysilane, γ-acryloxypropylethyldimethoxysilane, and γ-acryloxy. Propyltrimethoxysilane, γ-acryloxypropyldimethylethoxysilane, γ-acryloxypropylmethyldiethoxysilane, γ-acryloxypropyldiethylethoxysilane, γ-acryloxypropylethyldiethoxysilane, γ-acryloxypropyltriethoxy Silane, γ-methacryloxypropyldimethylmethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyldiethylmethoxysilane, γ-methacryloxy Propylethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyldimethylethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyldiethylethoxysilane, γ-methacryloxypropylethyldiethoxy Silane, γ-methacryloxypropyltriethoxysilane, 8-acryloyloxyoctyldimethylmethoxysilane, 8-acryloyloxyoctylmethyldimethoxysilane, 8-acryloyloxyoctyldiethylmethoxysilane, 8-acryloyloxyoctylethyldimethoxysilane, 8-acryloyl Oxyoctyltrimethoxysilane, 8-acryloyloxyoctyldimethylethoxysilane, 8-acryloyloxyoct Rumethyldiethoxysilane, 8-acryloyloxyoctyldiethylethoxysilane, 8-acryloyloxyoctylethyldiethoxysilane, 8-acryloyloxyoctyltriethoxysilane, 8-methacryloyloxyoctyldimethylmethoxysilane, 8-methacryloyloxyoctylmethyldimethoxy Silane, 8-methacryloyloxyoctyldiethylmethoxysilane, 8-methacryloyloxyoctylethyldimethoxysilane, 8-methacryloyloxyoctyltrimethoxysilane, 8-methacryloyloxyoctyldimethylethoxysilane, 8-methacryloyloxyoctylmethyldiethoxysilane, 8- Methacryloyloxyoctyldiethylethoxysilane, 8-methacryloyloxyoctylethyl Diethoxysilane, 8-methacryloyloxyoctyltriethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltriethoxysilane, 10-methacryloyloxydecyltriethoxysilane, 12 -Acryloyl oxide decyl trimethoxysilane, 12-methacryloyl oxide decyl trimethoxy silane, 12-acryloyl oxide decyl triethoxy silane, 12-methacryloyl oxide decyl triethoxy silane, etc. are mentioned.

From the viewpoint of preventing aggregation of the silica fine particles (a) in the curable composition, reducing the viscosity of the curable composition, and improving the storage stability, the silane compound (e) may be γ-acryloxypropyldimethylmethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-methacryloxypropyldimethylmethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, 8-methacryloyloxyoctyl Trimethoxysilane and 8-methacryloyloxyoctyltriethoxysilane are preferable, and 8-methacryloyloxyoctyltrimethoxysilane and 8-methacryloyloxyoctyltriethoxysilane are particularly preferable.
The silane compound (e) may be used alone or in combination of two or more.

  Such a silane compound (e) can be produced by a known method and is commercially available.

(Silane compound (f))
The silane compound (f) used in the present invention is a compound represented by the following general formula (2).

In formula (2), R ⁴ represents an alkyl group having 1 to 3 carbon atoms or a phenyl group, R ⁵ represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and c is an integer of 0 to 6. , D is an integer of 0-2. When d is 2, two R ⁴ may be the same or different, and when d is 1 or less, a plurality of R ⁵ may be the same or different.

R ⁴ represents an alkyl group having 1 to 3 carbon atoms or a phenyl group, and is preferably a methyl group or an ethyl group from the viewpoint of reducing the viscosity of the curable composition and storage stability, and facilitates the synthesis of the silane compound. Particularly preferred is a methyl group.
A substituent may be bonded to the phenyl group as long as the effects of the present invention are not impaired.

R ⁵ represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and is preferably an alkyl group having 1 to 5 carbon atoms from the viewpoint of reducing the viscosity of the curable composition and storage stability. Alternatively, an ethyl group is more preferable, and a methyl group is particularly preferable because of the ease of synthesis of the silane compound.

c is an integer of 0 to 6, preferably 0 or 1.
d is an integer of 0 to 2, preferably 0.

  When the silica fine particles (a0) react with the silane compound (f), the surface of the silica fine particles (a0) is imparted with hydrophobicity, and the dispersibility of the silica fine particles (a) in the organic solvent is improved. The compatibility between the fine particles (a) and the polymerizable component described later is improved. Thereby, the viscosity of the curable composition is reduced, and the storage stability of the curable composition is further improved.

  Examples of the silane compound (f) include phenyldimethylmethoxysilane, phenylmethyldimethoxysilane, phenyldiethylmethoxysilane, phenylethyldimethoxysilane, phenyltrimethoxysilane, phenyldimethylethoxysilane, phenylmethyldiethoxysilane, and phenyldiethylethoxysilane. , Phenylethyldiethoxysilane, phenyltriethoxysilane, benzyldimethylmethoxysilane, benzylmethyldimethoxysilane, benzyldiethylmethoxysilane, benzylethyldimethoxysilane, benzyltrimethoxysilane, benzyldimethylethoxysilane, benzylmethyldiethoxysilane, benzyldiethyl Ethoxysilane, benzylethyldiethoxysilane, and benzyltriethoxysilane, Phenyl dimethoxy silane, and the like.

From the viewpoint of reducing the viscosity of the curable composition and improving the storage stability, the silane compound (f) includes phenyldimethylmethoxysilane, phenylmethyldimethoxysilane, phenyldiethylmethoxysilane, phenylethyldimethoxysilane, phenyltrimethoxysilane. Diphenyldimethoxysilane is preferred, and phenyltrimethoxysilane and diphenyldimethoxysilane are more preferred.
The silane compound (f) may be used alone or in combination of two or more.

  Such a silane compound (f) can be produced by a known method, and is commercially available.

The total amount of the silane compound used for the surface modification (the total amount of the silane compounds (e) and (f)) is 100 parts by mass of the silica fine particles (a0) before the surface modification (this is the silica fine particles not containing an organic solvent (a0)). The amount is usually 5 to 55 parts by mass, preferably 5 to 35 parts by mass, and most preferably 5 to 15 parts by mass.
When the amount of the silane compound used is less than the above range, the viscosity of the curable composition is increased and the curability is deteriorated, and the dispersibility of the silica fine particles (a) in the composition is deteriorated to gel, or the curable composition. The heat resistance of the silica particle-containing fine concavo-convex structure obtained from the above may decrease. When the amount of the silane compound used exceeds the above range, a reaction between the silica fine particles occurs during the surface modification of the silica fine particles (a0), thereby causing aggregation or gelation of the silica fine particles (a) in the curable composition. May cause.
The amount of the silane compound (e) is 20 to 5 parts by mass, preferably 15 to 5 parts by mass, and more preferably 10 to 5 parts by mass with respect to 100 parts by mass of the silica fine particles (a0) before the surface treatment.
The amount of the silane compound (f) is 15 to 3 parts by mass, preferably 10 to 3 parts by mass, and more preferably 6 to 3 parts by mass with respect to 100 parts by mass of the silica fine particles (a0) before the surface treatment.

The amount of the silane compound (e) is usually 1 to 100% by mass, preferably 20 to 100% by mass, and more preferably 50 to 70% by mass with respect to the total amount of the silane compound used for the surface modification.
The amount of the silane compound (f) is usually 1 to 100% by mass, preferably 1 to 70% by mass, and more preferably 30 to 50% by mass with respect to the total amount of the silane compound used for the surface modification.
The mass ratio of the silane compound (e) and the silane compound (f) is preferably 1: 3 to 3: 1 in terms of the mass of the silane compound (e): the mass of the silane compound (f).

<Polymerizable component>
The curable composition contains a polymerizable component such as a monomer, oligomer, or reactive polymer having a radical polymerizable bond and / or a cationic polymerizable bond in the molecule.
It is preferable that the monomer which has a meta (acrylate) group from a sclerosing | hardenable viewpoint by an active energy ray, and the monomer which has a meta (acrylate) group with respect to 100 mass parts of silica fine particles (a0) before surface treatment is 20- It is preferable to contain 450 parts by mass, more preferably 60 to 350 parts by mass, and even more preferably 140 to 350 parts by mass.
Examples of the monomer having a meta (acrylate) group include a trifunctional or higher polyfunctional (meth) acrylate (A) and a bifunctional (meth) acrylate (B).
More specifically, from the viewpoint of scratch resistance after curing, 10 to 250 mass of trifunctional or higher polyfunctional (meth) acrylate (A) with respect to 100 mass parts of silica fine particles (a0) before surface treatment. Part, preferably 30 to 200 parts by weight, more preferably 70 to 200 parts by weight. When the content of the trifunctional or higher polyfunctional (meth) acrylate (A) is 10 parts by mass or more, a sufficient elastic modulus is imparted to the convex part, and unification of the convex part can be prevented. When the content of the trifunctional or higher polyfunctional (meth) acrylate (A) is 250 parts by mass or less, sufficient convexity is imparted to the convex part, and the scratch resistance is improved.
Further, from the viewpoint of scratch resistance after curing, it is preferable that 10 to 200 parts by mass of the bifunctional polyfunctional (meth) acrylate (B) is contained with respect to 100 parts by mass of the silica fine particles (a0) before the surface treatment. 30 to 150 parts by mass are more preferable, and 70 to 150 parts by mass are further preferable. If content of bifunctional (meth) acrylate (A) is 10 mass parts or more, sufficient softness | flexibility will be provided to a convex part and abrasion resistance will become favorable. If content of bifunctional (meth) acrylate (B) is 200 mass parts or less, sufficient elastic modulus will be provided to a convex part and coalescence of a convex part can be prevented. In addition, when using the below-mentioned polyethylene glycol di (meth) acrylate as bifunctional (meth) acrylate (B), the content of polyethylene glycol di (meth) acrylate is the silica fine particles (a0) 100 before the surface treatment. It is preferable that it is 30-180 mass parts with respect to a mass part, and it is more preferable that it is 33-150 mass parts. Moreover, when using the below-mentioned polypropylene glycol di (meth) acrylate as bifunctional (meth) acrylate (B), the content of polypropylene glycol di (meth) acrylate is the silica fine particles (a0) 100 before the surface treatment. It is preferable that it is 30-150 mass parts with respect to a mass part, and it is more preferable that it is 50-100 mass parts.

  As trifunctional or higher polyfunctional (meth) acrylate (A), pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethylene oxide modified tri (meth) acrylate, trimethylolpropane propylene oxide Trifunctional monomers such as modified triacrylate, trimethylolpropane ethylene oxide modified triacrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate, condensation reaction mixture of succinic acid / trimethylolethane / acrylic acid, dipentaerystol hexa ( (Meth) acrylate, dipentaerystol penta (meth) acrylate, ditrimethylolpropane tetraacrylate, tetramethylolmethanetetra (meth) acryl Over DOO, monomers polyfunctional such as ethylene oxide modified dipentaerythritol hexa (meth) acrylate. Of these, ethylene oxide-modified dipentaerythritol hexa (meth) acrylate is preferable. These may be used alone or in combination of two or more.

  As the bifunctional (meth) acrylate (B), polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, ethylene isocyanurate Oxide-modified di (meth) acrylate, triethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,5-pentane Diol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, polybutylene glycol di (meth) acrylate, 2,2-bis (4- (meth) acryloxypolyethylene Phenyl) propane, 2,2-bis (4- (meth) acryloxyethoxyphenyl) propane, 2,2-bis (4- (3- (meth) acryloxy-2-hydroxypropoxy) phenyl) propane, 1,2 -Bis (3- (meth) acryloxy-2-hydroxypropoxy) ethane, 1,4-bis (3- (meth) acryloxy-2-hydroxypropoxy) butane, dimethylol tricyclodecane di (meth) acrylate, bisphenol A Ethylene oxide adduct di (meth) acrylate, propylene oxide adduct di (meth) acrylate of bisphenol A, neopentyl glycol di (meth) acrylate of hydroxypivalate, divinylbenzene, methylenebisacrylamide and the like. Of these, polyethylene glycol di (meth) acrylate and polypropylene glycol di (meth) acrylate are preferable. These may be used alone or in combination of two or more.

As a combination of a trifunctional or higher polyfunctional (meth) acrylate (A) and a bifunctional (meth) acrylate (B), ethylene oxide-modified dipentaerythritol hexa (meth) acrylate and polyethylene glycol di (meth) acrylate or A combination with polypropylene glycol di (meth) acrylate is preferred.
When a trifunctional or higher polyfunctional (meth) acrylate (A) and a bifunctional (meth) acrylate (B) are used in combination, a trifunctional or higher polyfunctional (meth) acrylate (A) and a bifunctional (meta) ) The mass ratio with acrylate (B) is expressed as the mass of trifunctional or higher polyfunctional (meth) acrylate (A): the mass of bifunctional (meth) acrylate (B), and 3: 1 to 1: 1. It is preferable that it is 2: 1 to 1: 1.

<Polymerization initiator>
The curable composition contains a polymerization initiator.
Examples of the polymerization initiator include known ones.
When the curable composition is cured using a photoreaction, examples of the photopolymerization initiator include a radical polymerization initiator and a cationic polymerization initiator.
Any radical polymerization initiator may be used as long as it generates an acid upon irradiation with a known active energy ray. An acetophenone-based photopolymerization initiator, a benzoin-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, or a thioxanthone-based light is used. Examples thereof include polymerization initiators and acylphosphine oxide photopolymerization initiators. These radical polymerization initiators may be used alone or in combination of two or more.

  Examples of the acetophenone photopolymerization initiator include acetophenone, p- (tert-butyl) -1 ′, 1 ′, 1′-trichloroacetophenone, chloroacetophenone, 2 ′, 2′-diethoxyacetophenone, hydroxyacetophenone, 2, Examples include 2-dimethoxy-2′-phenylacetophenone, 2-aminoacetophenone, dialkylaminoacetophenone, and the like.

  Examples of the benzoin photopolymerization initiator include benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-2 -Methylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, benzyldimethyl ketal and the like.

  Examples of the benzophenone photopolymerization initiator include benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, methyl-o-benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, hydroxypropylbenzophenone, acrylic benzophenone, 4,4′-bis ( And dimethylamino) benzophenone.

  Examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, diethylthioxanthone, and dimethylthioxanthone.

  Examples of the acylphosphine oxide photopolymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzoyldiethoxyphosphine oxide, and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide. .

  Examples of other radical polymerization initiators include α-acyl oxime ester, benzyl- (o-ethoxycarbonyl) -α-monooxime, glyoxy ester, 3-ketocoumarin, 2-ethylanthraquinone, camphorquinone, tetramethylthiuram sulfide. Azobisisobutyronitrile, benzoyl peroxide, dialkyl peroxide, tert-butyl peroxypivalate and the like.

  Any cationic polymerization initiator may be used as long as it generates an acid upon irradiation with a known active energy ray, and examples thereof include sulfonium salts, iodonium salts, and phosphonium salts. These cationic polymerization initiators may be used alone or in combination of two or more.

  Examples of the sulfonium salt include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, bis (4- (diphenylsulfonio) -phenyl) sulfide-bis (hexafluorophosphate), bis (4- (diphenylsulfonio). ) -Phenyl) sulfide-bis (hexafluoroantimonate), 4-di (p-toluyl) sulfonio-4'-tert-butylphenylcarbonyl-diphenylsulfide hexafluoroantimonate, 7-di (p-toluyl) sulfonio- Examples include 2-isopropylthioxanthone hexafluorophosphate and 7-di (p-toluyl) sulfonio-2-isopropylthioxanthone hexafluoroantimonate.

  Examples of the iodonium salt include diphenyl iodonium hexafluorophosphate, diphenyl iodonium hexafluoroantimonate, bis (dodecylphenyl) iodonium tetrakis (pentafluorophenyl) borate, and the like.

  Examples of the phosphonium salt include tetrafluorophosphonium hexafluorophosphate and tetrafluorophosphonium hexafluoroantimonate.

When the curable composition is cured using a thermal reaction, examples of the thermal polymerization initiator include organic peroxides (methyl ethyl ketone peroxide, benzoyl peroxide, dicumyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, tert- Butyl peroxyoctoate, tert-butylperoxybenzoate, lauroyl peroxide, etc.), azo compounds (azobisisobutyronitrile, etc.), amines (N, N-dimethylaniline, N, N-dimethyl- and redox polymerization initiators combined with p-toluidine).
These thermal polymerization initiators may be used alone or in combination of two or more.

Among them, 1-hydroxycyclohexyl phenyl ketone and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide are preferable as the polymerization initiator.
It is preferable that content of a polymerization initiator is 1-5 mass parts with respect to 100 mass parts of polymeric components. If the content of the polymerization initiator is 5 parts by mass or more, the initiator becomes excessive and may not be economical. When content of a polymerization initiator is 1 mass part or less, there exists a possibility that hardening reaction may not fully advance.

<Other ingredients>
The curable composition is also added with a viscosity modifier such as acryloylmorpholine and vinylpyrrolidone, an adhesion improver such as acryloyl isocyanate that improves adhesion to the substrate, and a non-reactive polymer. be able to.

  Moreover, you may add the polymer (oligomer) of the low polymerization degree which superposed | polymerized 1 type (s) or 2 or more types of the monofunctional monomer to the said curable composition. Specific examples of such a polymer having a low degree of polymerization include, for example, monofunctional (meth) acrylates having a polyethylene glycol chain in the ester group (for example, “M-230G” (trade name), Shin-Nakamura Chemical Co., Ltd. And 40/60 copolymerized oligomers of methacrylamidopropyltrimethylammonium methyl sulfate (for example, “MG polymer” (trade name) manufactured by MRC Unitech Co., Ltd.).

≪Method for producing curable composition≫
For example, the curable composition may be prepared by subjecting silica fine particles (a0) (colloidal silica) dispersed in an organic solvent to surface treatment with silane compounds (e) and (f), thereby surface-treated silica fine particles (a). Step (step 1) for obtaining a uniform mixture of the surface-treated silica fine particles (a) by uniformly mixing polymerizable components (step 2), polymerization with the silica fine particles (a) obtained in step 2 The step of obtaining a desolvated composition by distilling off and desolvating the organic solvent and water from the homogeneous mixed solution with the active ingredient (step 3), the polymerization initiator in the desolvated composition obtained in step 3 Can be produced by sequentially carrying out the step (step 4) of adding a curable composition and uniformly mixing to obtain a curable composition. Each step will be described below.

(Process 1)
In step 1, the silica fine particles (a) dispersed in the organic solvent are surface-treated with the silane compounds (e) and (f) to obtain the surface-treated silica fine particles (a). In the surface treatment, silica fine particles (a0) are put into a reactor, and while stirring, the silane compounds (e) and (f) are added, stirred and mixed, and water necessary for further hydrolysis of the silane compound is added. While adding a catalyst and stirring, the silane compound is hydrolyzed and subjected to condensation polymerization on the surface of the silica fine particles (a0). As described above, it is preferable to use silica fine particles dispersed in an organic solvent as the silica fine particles (a0).

  As said organic solvent, it is preferable to use what melt | dissolves the organic component contained in a curable composition. Examples of the organic solvent include alcohol solvents, ketone solvents, ester solvents, and glycol ether solvents. Alcohol solvents such as methanol, ethanol, isopropyl alcohol, butyl alcohol, and n-propyl alcohol; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone are preferred because of the ease of distilling off volatile components in Step 3.

  The content of the silica fine particles (a0) in the colloidal silica is preferably 1 to 60% by mass with respect to the total mass of the colloidal silica (the total of the organic solvent and the silica fine particles) from the viewpoint of dispersibility in the curable composition. More preferably, it is 10-50 mass%, More preferably, it is 20-40 mass%.

  The disappearance of the silane compound due to hydrolysis can be confirmed by gas chromatography. Using gas chromatography (manufactured by Agilent, Model 6850), a nonpolar column DB-1 (manufactured by J & W) is used, the temperature is 50 to 300 ° C., the heating rate is 10 ° C./min, and He is used as the carrier gas. The residual amount of the silane compound can be measured by an internal standard method using a hydrogen ionization detector at a flow rate of 1.2 cc / min. By measuring the residual amount, disappearance due to hydrolysis of the silane compound can be confirmed.

  The amount of water necessary for carrying out the hydrolysis reaction is preferably about 0.1 to 10 mole equivalent, more preferably 1 to 10 mole equivalent, and further preferably 1 to 1 mole equivalent per 1 mole equivalent of the silane compound. 5 molar equivalents. If the amount of water is too small, the hydrolysis rate may become extremely slow, resulting in poor economic efficiency, and insufficient surface modification. If the amount of water is excessively large, the silica fine particles (a0) may form a gel.

When performing the hydrolysis reaction, a catalyst for the hydrolysis reaction is usually used.
Examples of the catalyst for the hydrolysis reaction include inorganic acids such as hydrochloric acid (aqueous hydrogen chloride), acetic acid, sulfuric acid and phosphoric acid; formic acid, propionic acid, oxalic acid, paratoluenesulfonic acid, benzoic acid, phthalic acid and maleic acid Organic acids such as potassium hydroxide, sodium hydroxide, calcium hydroxide and ammonia; organic metals; metal alkoxides; organotin compounds such as dibutyltin dilaurate, dibutyltin dioctylate and dibutyltin diacetate; aluminum tris (acetyl) Acetonate), titanium tetrakis (acetylacetonate), titanium bis (butoxy) bis (acetylacetonate), titanium bis (isopropoxy) bis (acetylacetonate), zirconium bis (butoxy) bis (acetylacetonate) Over G) and metal chelate compounds such as zirconium bis (isopropoxy) bis (acetylacetonate); boron compounds such as boron butoxide and boric acid. Among these, hydrochloric acid, acetic acid, maleic acid, and boron compounds are preferable because of their solubility in water and sufficient hydrolysis rate.
The catalyst for the hydrolysis reaction may be used alone or in combination of two or more.

  In performing the hydrolysis reaction of the silane compounds (e) and (f) in Step 1, it is preferable to use a highly water-soluble catalyst from the viewpoint of more uniformly dispersing the catalyst in the reaction system. More specifically, it is preferable to use a highly water-soluble catalyst having a solubility in 100 g of water of about 10 g or more.

  Although the addition amount of the catalyst used for a hydrolysis reaction is not specifically limited, Usually, 0.1-10 mass parts with respect to 100 mass parts of silica fine particles (a0), Preferably it is 0.5-5 mass parts. In the present invention, the catalyst may be used in the hydrolysis reaction as an aqueous solution dissolved in water (hereinafter also referred to as “catalyst aqueous solution”). The addition amount as the whole aqueous solution is represented.

  Although the reaction temperature of a hydrolysis reaction is not specifically limited, Usually, it is the range of 10-80 degreeC, Preferably it is the range of 20-50 degreeC. If the reaction temperature is excessively low, the hydrolysis rate becomes extremely slow, so that there is a possibility that the economy is insufficient or the surface treatment does not proceed sufficiently. On the other hand, when the reaction temperature is excessively high, the gelation reaction tends to occur.

  The reaction time for carrying out the hydrolysis reaction is not particularly limited, but is usually in the range of 10 minutes to 48 hours, preferably 30 minutes to 24 hours.

  The surface treatment with the silane compound (e) and the silane compound (f) in step 1 may be carried out sequentially, but it is preferable to carry out the surface treatment at the same time in terms of simplification and efficiency of the reaction process.

(Process 2)
There is no restriction | limiting in particular in the method of mixing the silica particle (a) by which surface treatment was carried out in the process 2, and a polymeric component. Examples of the mixing method include mixing with a mixer such as a mixer, ball mill, and three rolls at room temperature or under heating conditions, and adding a polymerizable component while continuously stirring in the reactor in which Step 1 was performed. The method of mixing is mentioned.

(Process 3)
In step 3, in order to distill off the organic solvent and water from the homogeneous mixture of the silica fine particles (a) and the polymerizable component and to remove the solvent (hereinafter collectively referred to as “desolving”), heating is performed under reduced pressure. Is preferred.

  The temperature is preferably maintained at 20 to 100 ° C., and more preferably 30 to 70 ° C., more preferably 30 to 50 ° C., in order to balance the prevention of aggregation gelation of the curable composition and the solvent removal speed. is there. If the temperature is raised too much, the fluidity of the curable composition may be extremely lowered, or the curable composition may be gelled.

  The degree of vacuum in the reduced pressure state is usually 10 to 4,000 kPa, and more preferably 10 to 1,000 kPa, most preferably, in order to balance the prevention of aggregation gelation of the curable composition and the solvent removal speed. 10-500 kPa. If the value of the degree of vacuum is too large, the desolvation speed becomes extremely slow and the economy is lacking.

  It is preferred that the desolvated composition is substantially free of solvent. The term “substantially” as used herein means that when the silica particle-containing fine uneven structure is actually obtained using the curable composition, it is not necessary to go through the step of removing the solvent again. Specifically, the remaining amount of the organic solvent and water in the curable composition is preferably 1% by mass or less, more preferably 0.5% by mass or less, and still more preferably with respect to the total mass of the curable composition. Means 0.1% by mass or less.

  In step 3, before removing the solvent, 100 parts by mass of the desolvated composition (that is, when the mass obtained by removing the organic solvent and water from the homogeneous mixed solution is 100 parts by mass), 0.1 You may add the polymerization inhibitor below a mass part. The polymerization inhibitor can be used to prevent components in the composition from undergoing a polymerization reaction during the solvent removal process or during the storage of the composition and the curable composition after the solvent removal.

  Step 3 can be performed by transferring the homogeneous mixed liquid of the silica fine particles (a) and the polymerizable component that have passed through Step 2 to a dedicated apparatus. When Step 2 is performed in the reactor used in Step 1, Step 3 can be performed in the reactor subsequent to Step 2.

(Process 4)
In Step 4, there is no particular limitation on the method of adding a polymerization initiator to the composition desolvated in Step 3 and mixing them uniformly. As the mixing method, for example, a method of mixing at room temperature by a mixer such as a mixer, a ball mill, or a three-roller, or a polymerization initiator is added while continuously stirring in the reactor in which steps 1 to 3 are performed. The method of mixing is mentioned.

  Furthermore, you may filter as needed with respect to the curable composition obtained by adding and mixing such a polymerization initiator. This filtration is performed for the purpose of removing foreign substances such as dust in the curable composition. The filtration method is not particularly limited, but a method of pressure filtration using a membrane type or cartridge type filter having a pressure filtration pore size of 1.0 μm is preferable.

  Further, the curable composition may contain an antistatic agent, a release agent, an ultraviolet absorber, and the like in addition to the above-described various monomers and polymers having a low polymerization degree.

≪Silica particle-containing fine uneven structure≫
FIG. 1 is a schematic cross-sectional view showing an example of the structure of a laminate 10 having the silica particle-containing fine uneven structure 12 of the present invention as a surface layer. In FIG. 1, the surface layer which is the silica particle containing fine concavo-convex structure 12 formed from the curable composition is formed on the surface of the substrate 11. In the laminate 10, a fine uneven structure is formed on the surface of the silica particle-containing fine uneven structure 12. In FIG. 1, the fine concavo-convex structure has a plurality of substantially conical convex portions 13.
FIG. 2 is a schematic cross-sectional view showing an example of the configuration of a laminate 10 ′ having a silica particle-containing fine uneven structure 12 ′ of the present invention as a surface layer. In FIG. 2, the surface layer which is the silica particle containing fine concavo-convex structure 12 'formed from the curable composition is formed on the surface of the substrate 11'. In the laminate 10 ′, a fine uneven structure is formed on the surface of the silica particle-containing fine uneven structure 12 ′. In FIG. 2, the fine concavo-convex structure has a plurality of bell-shaped convex portions 13 ′.

  In the laminate 10 (or 10 ′), it is preferable that the fine uneven structure is formed on the entire surface of the silica particle-containing fine uneven structure 12 (or 12 ′), but the silica particle-containing fine uneven structure 12 ( Alternatively, a structure in which a fine uneven structure is formed on a part of the surface of 12 ′) may be used. Moreover, when the laminated body 10 (or 10 ') has a film shape, fine concavo-convex structures may be formed on both surfaces. The fine concavo-convex structure is preferably formed by self-organization.

  In the fine concavo-convex structure, the pitch w1 (or w1 ′) of the convex portions is not more than the wavelength of visible light (400 nm) and is preferably 50 nm or more, more preferably 100 nm or more and 250 nm or less. By setting the thickness to 100 nm or more, it is possible to effectively prevent protrusions between the protrusions. By setting it to 250 nm or less, since it becomes sufficiently smaller than the wavelength of visible light, scattering of visible light is effectively suppressed, and excellent antireflection properties are easily imparted.

  In the present invention, “visible light wavelength” means a wavelength of 400 nm.

  The height d1 (or d1 ') of the convex portion 13 is preferably 100 nm or more, and more preferably 150 nm or more. By setting the height d1 (or d1 ') to 100 nm or more, it is possible to prevent an increase in the minimum reflectance and an increase in the reflectance at a specific wavelength, and it is easy to impart good antireflection properties.

  The aspect ratio (height of the protrusion 13 (or 13 ′) / pitch of the protrusion) is preferably 0.5 to 5.0, more preferably 0.6 to 2.0, and 0 More preferably, it is 8 to 1.2. When the aspect ratio is 0.5 or more, an increase in the minimum reflectance and an increase in the reflectance at a specific wavelength can be suppressed, and good antireflection properties are exhibited. In addition, when the aspect ratio is 5.0 or less, the convex portions of the fine concavo-convex structure are not easily broken when the silica particle-containing fine concavo-convex structure 12 (or 12 ′) is rubbed, so that excellent scratch resistance and antireflection are achieved. Sex is expressed.

In the present invention, the “height of the convex portion” means from the tip 13a (or 13a ′) of the convex portion 13 (or 13 ′) to the bottom portion 14a (or 14a ′) of the adjacent concave portion 14 (or 14 ′). This is the vertical distance. Further, the shape of the convex portion 13 (or 13 ′) of the fine concavo-convex structure is not particularly limited, but in order to obtain an antireflection function that achieves both low reflectance and low wavelength dependency by continuously increasing the refractive index. In addition, cut along a plane parallel to the film surface, such as a cone-shaped convex portion (for example, a substantially conical convex portion as shown in FIG. 1) or a bell-shaped convex portion as shown in FIG. It is preferable that the occupancy ratio of the cross-sectional area at this time is a structure that continuously increases toward the substrate side. In addition, a plurality of finer convex portions may be combined to form the fine concavo-convex structure.
The pitch of the protrusions and the height of the protrusions can be determined by, for example, observing the fine uneven structure under the condition of an acceleration voltage of 3.00 kV using a scanning electron microscope (manufactured by JEOL Ltd., “JSM-7400F”). Can be measured.

  The method for forming the fine concavo-convex structure is not particularly limited, and examples thereof include a method of injection molding or press molding using a stamper in which the fine concavo-convex structure is formed. For example, a curable composition is filled between a stamper on which a fine concavo-convex structure is formed and a substrate, the curable composition is cured by irradiation with active energy rays to transfer the concavo-convex shape of the stamper, and then released. A method is also mentioned. In addition, as a method for forming a fine concavo-convex structure, a curable composition is filled between a stamper on which a fine concavo-convex structure is formed and a substrate, and after the concavo-convex shape of the stamper is transferred to the curable composition, release is performed. The method of irradiating an active energy ray after that and hardening a curable composition is also mentioned. Among these, considering the transferability of the concavo-convex structure and the degree of freedom of the surface composition, the curable composition is filled between the stamper and the substrate on which the fine concavo-convex structure is formed and irradiated with active energy rays. A method of releasing the mold after curing the object and transferring the uneven shape of the stamper is preferably used.

  The substrate is not particularly limited, but is preferably a transparent substrate. The transparent substrate is not particularly limited as long as it transmits light. Examples of the transparent substrate material include methyl methacrylate (co) polymer, polycarbonate, styrene (co) polymer, methyl methacrylate-styrene copolymer, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, polyester, polyamide , Polyimide, polyether sulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polyurethane, glass, crystal and the like. The transparent substrate may be produced by any method of injection molding, extrusion molding, and cast molding.

  The shape of the substrate is not particularly limited and can be appropriately selected depending on the application. For example, when the application is an antireflection film, it is preferably a sheet or film. In order to improve adhesion to the curable composition, antistatic properties, scratch resistance, weather resistance, and the like, the surface of the substrate may be subjected to, for example, various coatings and corona discharge treatment.

  The method for producing the stamper on which the fine concavo-convex structure is formed is not particularly limited, and examples thereof include an electron beam lithography method and a laser light interference method. For example, after applying an appropriate photoresist film on an appropriate support substrate, exposure is performed using light such as an ultraviolet laser, an electron beam, or X-ray, followed by development to form a mold having a fine concavo-convex structure. . This mold can also be used as a stamper. It is also possible to form a fine concavo-convex structure directly on the support substrate itself by selectively etching the support substrate through dry etching through the photoresist layer and then removing the photoresist layer.

  Anodized porous alumina can also be used as a stamper. For example, as disclosed in JP-A-2005-156695, an alumina nanohole array obtained by a method of anodizing aluminum at a predetermined voltage in an electrolyte such as oxalic acid, sulfuric acid, phosphoric acid, etc. is used as a stamper. May be. According to this method, after anodizing high-purity aluminum for a long time at a constant voltage, pores having very high regularity can be formed in a self-organizing manner by once removing the oxide film and anodizing again. . Further, by combining the anodizing treatment and the hole diameter expanding treatment when anodizing again, it is possible to form a fine concavo-convex structure in which the concave portion has a bell shape in addition to the substantially conical shape. Alternatively, a replica mold may be produced from an original mold having a fine concavo-convex structure by electroforming or the like and used as a stamper.

  The shape of the stamper thus produced is not particularly limited, and may be a flat plate shape or a roll shape. However, from the viewpoint of continuously transferring the fine concavo-convex structure to the curable composition, the roll shape is preferable.

  Specific examples of the active energy ray used for curing the curable composition include visible light, ultraviolet light, electron beam, plasma, and infrared light.

The irradiation of the active energy ray is performed using, for example, a high-pressure mercury lamp. The integrated light irradiation energy amount is not particularly limited as long as the curing of the curable composition proceeds, but for example, 100 to 5000 mJ / cm ² is preferable, 200 to 4000 mJ / cm ² is more preferable, and 400 to 3200 mJ is preferable. / Cm ² is more preferable. Since the integrated light irradiation amount of the active energy ray may affect the degree of curing of the curable composition, it is desirable to select appropriately and irradiate light.

  As a method for measuring the surface fine concavo-convex structure of the cured product, for example, observation with an electron microscope may be mentioned. Specifically, after depositing platinum on the surface of the cured product for 10 minutes, using a scanning electron microscope (“JSM-7400F” manufactured by JEOL Ltd.), the surface of the stamper and the laminated body under the condition of an acceleration voltage of 3.00 kV The fine concavo-convex structure formed on the surface is observed, the pitch of the convex portion and the height of the convex portion are measured from the obtained image, and the average value of 10 measurement results randomly extracted is used as the pitch width. There is a way.

The ratio of the silica fine particles (a0) before the surface treatment is preferably 10 to 80% by mass, more preferably 20 to 45% by mass, based on the total mass of the silica particle-containing fine uneven structure. If it is this range, it can be set as the silica particle containing fine uneven structure which has sufficient intensity | strength and heat resistance.
The “ratio of silica fine particles (a0) before the surface treatment in the silica particle-containing fine uneven structure” refers to the silane compound (e) and the silane in the silica fine particles (a) in the silica particle-containing fine uneven structure. It means the proportion of silica fine particles (a0) excluding the portion surface-treated with the compound (f).

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

<Adjustment of curable composition>
[Example 1]
100 g of isopropyl alcohol-dispersed colloidal silica (silica fine particle content 30% by mass, number average particle size 100 nm, trade name: IPA-ST-ZL; manufactured by Nissan Chemical Industries, Ltd.) is placed in a separable flask. As a silane compound, 1.8 g of 8-methacryloyloxyoctyltrimethoxysilane (MOS) and 1.2 g of phenyltrimethoxysilane (PhS) are added and mixed with stirring. The silica fine particles were surface-modified by adding 0 g and stirring at 25 ° C. for 24 hours.
30 g of polyethylene glycol diacrylate (trade name: M260; manufactured by Toa Gosei Co., Ltd.) as a bifunctional polyfunctional (meth) acrylate (B) is added to the dispersion containing the surface-modified silica fine particles. As the polyfunctional (meth) acrylate (A), 60 g of ethylene oxide-modified dipentaerythritol hexaacrylate (trade name: DPEA-12; manufactured by Nippon Kayaku Co., Ltd.) was added and mixed uniformly. Then, it heated under reduced pressure at 40 degreeC and 100 kPa, stirring, and removed the volatile matter, and obtained the composition.

  The disappearance due to hydrolysis of the silane compounds (here, MOS and PhS) was confirmed by gas chromatography (model 6850; manufactured by Agilent). Nonpolar column DB-1 (manufactured by J & W) is used, temperature is 50 to 300 ° C., heating rate is 10 ° C./min, He is used as a carrier gas, flow rate is 1.2 cc / min, and a flame ionization detector is used. The internal standard method was used. MOS and PhS disappeared 8 hours after the addition of the hydrochloric acid.

  1 g of Irgacure 184 (trade name, manufactured by BASF) and 0.5 part of Irgacure 819 (trade name, manufactured by BASF) were added to 100 g of the obtained composition as a photopolymerization initiator. The obtained solution was subjected to pressure filtration (pressure 0.2 MPa) with a membrane filter (pore diameter 1.0 μm) to obtain a curable composition.

[Examples 2-16, Comparative Examples 1-2]
A curable composition was prepared in the same manner as in Example 1 except that the number average particle size of the isopropyl alcohol-dispersed colloidal silica and the type and amount of the polyfunctional monomer were changed as shown in Table 1.

<Formation of fine uneven structure>
A few drops of the curable composition are placed on a stamper having an infinite number of fine concavo-convex structures having a distance between adjacent concave portions of 180 nm and a concave portion depth of 150 nm, and a triacetyl cellulose film (FTTD80ULM (trade name), Fuji Film Co., Ltd.). The curable composition was coated while being spread. Subsequently, by irradiating ultraviolet rays from the film side with an energy of an integrated light irradiation amount of 1000 mJ / cm ² to photocur the curable composition and then peeling the cured product from the stamper, as shown in FIG. A fine concavo-convex structure having a convex portion pitch w1 of 180 nm and a convex portion height d1 of 150 nm was obtained.

<Evaluation>
Each evaluation of pencil hardness and scratch resistance of the obtained fine concavo-convex structure was performed according to the following procedures. The results are shown in Table 1.

<Various evaluations and measurement methods>
(Pencil hardness test)
In accordance with JIS K5600-5-4, the test was performed with a load of 500 g. At 5 minutes after the test, the appearance was visually observed, and the hardness of the pencil without scratches was noted. (If B is not scratched and HB is scratched, it is written as “B”.)
(Measurement of scratch resistance)
When the surface layer was rubbed with Kay Dry (manufactured by Nippon Paper Crecia Co., Ltd.) at a pressure of 100 g / cm ² , the case where no scratch was generated was evaluated as “◯”, and the case where the scratch was generated was evaluated as “X”.

Abbreviations in Table 1 are as follows.
DPEA-12: ethylene oxide modified dipentaerythritol hexaacrylate, trade name: DPEA-12 manufactured by Nippon Kayaku Co., Ltd. M260: polyethylene glycol diacrylate, trade name: M260, manufactured by Toagosei Co., Ltd. APG700: polypropylene glycol diacrylate Product name: APG700, manufactured by Shin-Nakamura Chemical Co., Ltd., silica fine particles with a particle size of 100 nm: manufactured by Nissan Chemical Industries, Ltd., product name: IPA-ST-ZL, silica fine particle content: 30% by mass, number average particle size: 100 nm,
Silica fine particles having a particle diameter of 200 nm: manufactured by Nissan Chemical Industries, Ltd., trade name: MEK-ST-2040, silica fine particle content of 30% by mass, number average particle diameter of 200 nm
Silica fine particles having a particle diameter of 300 nm: manufactured by Admatechs Co., Ltd., trade name: SC1050-IP Aslury, silica fine particle content 30 mass%, number average particle diameter 200 nm
Silica fine particles having a particle diameter of 500 nm: manufactured by Nissan Chemical Industries, Ltd., trade name: MEK-ST-4540, silica fine particle content of 30% by mass, number average particle diameter of 500 nm
Silica fine particles having a particle diameter of 10 nm: manufactured by Nissan Chemical Industries, Ltd., trade name: Snowtech IPA-ST, silica fine particle content of 30% by mass, number average particle diameter of 10 nm,

In the table, the unit of “use amount” is “g”.
“Particle size” means the number average particle size of silica fine particles before surface treatment. The amount of “silica fine particles” used is the mass of the solid content (silica fine particles before surface treatment) obtained by removing the organic solvent from colloidal silica.

  In the fine concavo-convex structure obtained in Examples 3 to 6 and 11 to 14, since the number average particle diameter of the silica fine particles before the surface treatment was sufficiently large, both the pencil hardness and the scratch resistance were good.

[Comparative Examples 1-2]
A fine concavo-convex structure was obtained in the same manner as in Example 1 except that the composition was changed to the composition shown in Table 1. The results are shown in Table 1.

The fine concavo-convex structure obtained in Comparative Example 1 had a low pencil hardness because it did not contain surface-treated silica fine particles.
In the fine concavo-convex structure obtained in Comparative Example 2, since the number average particle diameter of the silica fine particles before the surface treatment was 10 nm or less, the pencil hardness and the scratch resistance were poor.

10: Laminate 11: Substrate 12: Fine concavo-convex structure containing silica particles 13: Convex part 14: Concave part d1: Height w1: Pitch 10 ': Laminate 11': Substrate 12 ': Fine concavo-convex structure containing silica particles Body 13 ': Convex part 14': Concave part d1 ': Height w1': Pitch

Claims (4)

The silica particle containing fine concavo-convex structure which has the fine concavo-convex structure on the surface characterized by satisfying the following conditions 1 to 3.
1) The surface has a plurality of convex portions, and the pitch of the convex portions is 50 to 400 nm. 2) Curing containing surface-treated silica fine particles (a), a polymerizable component, and a polymerization initiator. The composition is cured,
The surface-treated silica fine particles (a) are silica fine particles (a0) having a number average particle diameter of 30 nm or more before surface treatment, and the silane compound (e) represented by the following general formula (1) and the following general formula ( 2) It is obtained by surface treatment with the silane compound (f) represented by 3) 3) The number average particle diameter of the silica fine particles (a0) before the surface treatment is 50 to 300 of the pitch of the convex portions. %.

(In Formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom, a phenyl group, or an alkyl group having 1 to 4 carbon atoms, and R ³ represents a hydrogen atom, a phenyl group, or 1 carbon atom. Represents a hydrocarbon group of 10 to 10, a is an integer of 1 to 16, and b is an integer of 0 to 3. When b is 2 or more, a plurality of R ² may be the same or different. And when b is 1 or less, a plurality of R ³ may be the same or different.)

(In the formula (2), ^{R 4} represents an alkyl group or a phenyl group having 1 to 3 carbon atoms, ^{R 5} represents a hydrocarbon group having 1 to 10 carbon hydrogen atom or a C, c is an integer from 0 to 6 And d is an integer from 0 to 2).   The silica particle-containing fine concavo-convex structure according to claim 1, wherein the number average particle diameter of the silica fine particles (a0) before the surface treatment is 150 to 550 nm, and the pitch of the convex portions is 100 to 250 nm.   The curable composition is composed of 10 to 250 parts by mass of a trifunctional or higher polyfunctional (meth) acrylate (A) as the polymerizable component with respect to 100 parts by mass of the silica fine particles (a0) before the surface treatment. The silica particle-containing fine concavo-convex structure according to claim 1 or 2, comprising 10 to 200 parts by mass of a functional polyfunctional (meth) acrylate (B).   The silica particle as described in any one of Claims 1-3 whose ratio of the silica particle (a0) before the said surface treatment is 20-45 mass% with respect to the total mass of a silica particle containing fine concavo-convex structure. Containing fine concavo-convex structure.

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