JP2003266605A - Transparent base having cured film formed thereon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a material having a sufficient antireflection performance only with a single antireflection film. <P>SOLUTION: A transparent base comprises a cured film formed of a cationic polymerizable compound, a hydrolyzable organic silicon compound and a composition containing porous fine particles and formed on the surface of the base. As the cationic polymerizable compound, an oxetane compound or an epoxy compound can be used. Particularly, the oxetane compound having a silyl group in a molecule or containing its hydrolyzable condensate as a main ingredient is effective. As the fine particles, silica fine particles are preferred. A silica having a double structure with its coated surface or a composite oxide containing the silica is effective. When the cured film has a refractive index of 1.20 to 1.45 and a film thickness of 0.01 to 1 μm, the film is operated as the film having the antireflection function. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent substrate having an antireflection cured coating formed on its surface.

[0002]

2. Description of the Related Art Conventionally, a functional coating film such as an antireflection film has been formed and used on the surface of a transparent substrate such as glass or resin for a display. In particular, from the viewpoint of cost, many base materials having a coating film obtained by applying an antireflection material as a paint, rather than the vapor deposition method or the sputtering method, have been developed. For example, JP-A-8-100136 discloses that a copolymer of vinylidene fluoride and hexafluoropropylene is blended with a polymerizable compound having an ethylenically unsaturated group, and is used for forming an antireflection film. A system paint is described.

However, the conventionally used antireflection film has an insufficient antireflection performance. For example, the one described in JP-A-8-100136 mentioned above has a refractive index of 1.4.
It was about 3, and sufficient antireflection performance was not obtained.
Further, in order to improve the antireflection performance, it is preferable that the antireflection layer has a two-layer structure composed of a high refractive index layer and a low refractive index layer.
As disclosed in Japanese Patent Laid-Open No. 2001-315242, in this case, the reflectance is reduced to 100 to 20 around a specific wavelength.
There is a problem that the reflected light is strongly colored due to interference because it is only in the wavelength range of 0 nm and the reflectance is high at other wavelengths.

[0004]

Therefore, the present inventor has conducted diligent research to develop a material having a sufficient antireflection property with a single-layer antireflection film, and as a result, a specific composition was cured. It was found that the coating film obtained in this way has sufficient antireflection performance, and the present invention has been completed.

[0005]

That is, according to the present invention, a cured coating is formed on the surface of a substrate from a composition containing a cationically polymerizable compound, a hydrolyzable organosilicon compound, and porous fine particles. A transparent substrate is provided.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The transparent substrate of the present invention has a cured coating formed on its surface, and this cured coating has a composition containing a cationically polymerizable compound, a hydrolyzable organosilicon compound and porous fine particles. Formed from things. Therefore, this cured film is a cured product of the cationically polymerizable compound and the hydrolyzable organosilicon compound in which the porous fine particles are dispersed. If the cured coating has an appropriate thickness and refractive index, it acts as an antireflection layer. This cured film is obtained by forming a film of a composition in which porous fine particles are dispersed in a mixture of a cationically polymerizable compound and a hydrolyzable organosilicon compound on a substrate and curing the film. be able to.

The cationically polymerizable compound is a compound which is cured by cationic polymerization. Specific examples include oxetane compounds and epoxy compounds, and a mixture thereof can also be used.

The oxetane compound is a compound having at least one oxetane ring in the molecule. As such an oxetane compound, various compounds can be used, and preferred compounds include those represented by the following formulas (I) to (III).

[0009]

In the formula, R ¹ represents hydrogen, fluorine, an alkyl group, a fluoroalkyl group, an allyl group, an aryl group or a furyl group, m represents an integer of 1 to 4, Z represents oxygen or sulfur, R ² represents a monovalent to tetravalent organic group depending on the value of m, n represents an integer of 1 to 5, p represents an integer of 0 to 2, R ³ represents hydrogen or an inert monovalent monovalent. Represents an organic group, R ⁴
Represents a hydrolyzable functional group.

In formulas (I) to (III), when R ¹ is an alkyl group, the number of carbon atoms can be about 1 to 6, and specific examples thereof include methyl, ethyl, propyl and butyl. To be The fluoroalkyl group also has 1 carbon atom.
It can be up to about 6. Further aryl groups are typically phenyl or naphthyl, which may be substituted with other groups.

Further, the organic group represented by R ² in the formula (I) is not particularly limited. For example, when m is 1, an alkyl group, a phenyl group or the like, and when m is 2,
A straight-chain or branched alkylene group having 1 to 12 carbon atoms, a straight-chain or branched poly (alkyleneoxy) group, etc., wherein m is 3
Alternatively, in case of 4, similar polyvalent functional groups can be mentioned.

The inert monovalent organic group represented by R ³ in the formula (III) typically includes an alkyl group having 1 to 4 carbon atoms, and is hydrolyzable represented by R ^4. Examples of such functional groups include alkoxy groups having 1 to 5 carbon atoms including methoxy and ethoxy, and halogen atoms such as chlorine atom and bromine atom.

Among the oxetane compounds, a compound having a silyl group in the molecule or a hydrolyzed condensate thereof is preferably used. In particular, the silsesquioxane compound having a plurality of oxetanyl groups (a network-like polysiloxane compound) obtained by hydrolytically condensing the compound of the formula (III) in the presence of an alkali and water gives a hard coating film. It is suitable as a material used in the present invention.

Any epoxy compound can be used as long as it is a monomer having at least one epoxy group in the molecule and can undergo cationic polymerization to be cured. For example, phenyl glycidyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, vinylcyclohexenedioxide, 1,2,8,9-diepoxylimonene, 3,4-epoxycyclohexylmethyl 3 ', 4'-epoxycyclohexanecarboxy. Rate, bis (3,4-epoxycyclohexyl) adipate and the like.

As the cationically polymerizable compound, it is particularly preferable to use an oxetane compound alone or in combination with an epoxy compound. In this case, the epoxy compound is usually 0 to 3 with respect to 100 parts by weight of the oxetane compound.
It is added in an amount of about 0 parts by weight, preferably about 1 to 20 parts by weight.

The hydrolyzable organosilicon compound is a compound having at least one hydrolyzable group in the molecule and having an organic group bonded to a silicon atom. Specifically, the following formula (IV) Can be shown as

Si (R ⁵ ) _q (R ⁶ ) _4-q (IV)

In the formula, R ⁵ represents hydrogen or an inert monovalent organic group, R ⁶ represents a hydrolyzable functional group, and q represents 0.
Represents an integer of 3;

The inert monovalent organic group represented by R ⁵ in the formula (IV) is typically an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, phenyl or the like. Included are aryl groups and the like. The hydrolyzable functional group represented by R ⁶ includes, for example, an alkoxy group having 1 to 5 carbon atoms including methoxy and ethoxy, an acyloxy group such as acetoxy and propionyloxy, a chlorine atom and a bromine atom. Examples thereof include halogen atoms and substituted silylamino groups such as trimethylsilylamino. Well-known hydrolyzable organosilicon compounds are roughly classified into alkoxysilane compounds, halogenated silane compounds, acyloxysilane compounds and silazane compounds. These organosilicon compounds are substituted with aryl groups, vinyl groups, allyl groups, (meth) acryloyloxy groups, epoxy groups, amino groups, mercapto groups, etc. as a part of R ⁵ or R ⁶ in the above formula (IV). It may have a group.

Specific hydrolyzable organosilicon compounds include, for example, halogenated silane compounds such as methyltrichlorosilane, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, phenyltrimethoxysilane and phenyltriethoxysilane. , Dimethyldimethoxysilane, dimethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ
-Aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane,
N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane , An alkoxysilane compound such as γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropylmethyldimethoxysilane, a silazane compound such as hexamethyldisilazane, and the like. These can be used alone or in combination of two or more.

The hydrolyzable organosilicon compound may be a monomer as shown here, or a large amount such as an oligomer of a dimer to a 10mer or a polymer having a degree of polymerization of more than 10. It may be the body. Further, it may be a hydrolysis product obtained by hydrolyzing the above-mentioned organosilicon compound. The hydrolysis product can be produced by adding an acid such as hydrochloric acid, phosphoric acid, acetic acid, or a base such as sodium hydroxide or sodium acetate to the above organosilicon compound.

Further, as the hydrolyzable organosilicon compound, a compound having a fluorine atom in the molecule can be used. The hydrolyzable organosilicon compound having a fluorine atom in the molecule has at least one hydrolyzable group in the molecule.
It is a compound having an organic group having a fluorine atom on a silicon atom, and specifically, it can be represented by the following formula (V).

Rf-R ⁷ -Si (R ⁸ ) _r (R ⁹ ) _3-r (V)

In the formula, Rf is a linear or branched perfluoroalkyl group having 1 to 16 carbon atoms, R ⁷ is a divalent organic group,
R ⁸ represents hydrogen or an inert monovalent organic group, R ⁹ represents a hydrolyzable functional group, and r represents an integer of 0 to 2.

In the formula (V), R ⁷ is a divalent organic group, and specific examples include the following groups.

--CH ₂ CH _2- , --CH ₂ OCH ₂ CH ₂ C
_{H 2 -, - CONHCH 2 CH} 2 CH 2 -, - CONHCH
_{2 CH 2 NHCH 2 CH 2 CH} 2 -, - SO 2 NHCH 2 CH 2
_{CH 2 -, - CH 2 CH} 2 OCONHCH 2 CH 2 CH 2 -
Such.

R ⁸ is hydrogen or an inert monovalent organic group, and specific examples thereof are the same as R ⁵ in the formula (IV).
R ⁹ is a hydrolyzable functional group, and a specific example thereof is represented by the formula (I
It is the same as R ^{6 in} V).

As the hydrolyzable organosilicon compound having a fluorine atom in the molecule represented by the formula (V),
Specific examples include the following.

CF ₃ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , C ₄ F ₉
CH ₂ CH ₂ Si (OCH ₃ ) ₃ , C ₄ F ₉ CH ₂ CH ₂ Si (C
_{H 3) (OCH 3) 2} , C 8 F 17 CH 2 CH 2 Si (OCH 3)
₃ , C ₈ F ₁₇ CH ₂ CH ₂ Si (OC ₂ H ₅ ) ₃ , C ₈ F ₁₇ CH
_{2 CH 2 SiCl 3, (CF} 3) 2 CF (CF 2) 8 CH 2 CH 2 S
_{i (OCH 3) 3, C} 10 F 21 CH 2 CH 2 Si (OCH 3) 3,
Such as _{C 10 F 21 CH 2 CH 2} SiCl 3.

The porous fine particles are not particularly limited, but those having an average particle diameter in the range of 5 nm to 10 μm are preferably used. In particular, when forming a film as an antireflection film, fine particles having an average particle size in the range of 5 nm to 100 nm are more preferable. If the particle size is too small, it is difficult to industrially manufacture, and if the particle size becomes too large,
It is not preferable because the optical performance such as the transparency of the coating is deteriorated.

As the porous fine particles, silica fine particles are preferable because the material itself has a low refractive index and strength. Porous silica has a refractive index of about 1.2 to 1.4, which is lower than the refractive index of ordinary silica fine particles of 1.46, and is preferable for forming an antireflection material. The porous silica, for example, as shown in JP-A-7-48527, obtained by hydrolyzing an alkoxysilane in the presence of an alkali, highly entangled and branched, silica produced in the form of a polymer Is mentioned.

Further, as the porous fine particles, silica having a double structure whose surface is coated or a composite oxide containing silica may be used. Such a surface-coated silica having a double structure or a composite oxide containing silica,
For example, it can be produced by the method described in JP-A-7-133105. In particular, porous silica fine particles whose surface is coated to have a double structure are preferably used because the pore inlets of the particles are closed and the porosity inside the particles is maintained.

In the composition used for forming the cured film, the amount of each component is not particularly limited, but the cationically polymerizable compound is based on the total amount of the cationically polymerizable compound, the hydrolyzable organosilicon compound and the porous fine particles. Compound is usually 1
0 to 70% by weight, usually 1 of hydrolyzable organosilicon compound
0 to 70% by weight, porous fine particles are usually 20 to 80% by weight
Is the range. Further, based on the total amount of the cationically polymerizable compound and the hydrolyzable organosilicon compound, the amount of the cationically polymerizable compound is usually 20 to 80% by weight. If the amount of the cationically polymerizable compound is too small or too large, sufficient adhesion between the cured film and the substrate cannot be obtained. On the other hand, if the amount of the porous fine particles is too small, the refractive index of the cured coating may not be lowered, and a sufficient antireflection function may not be obtained. If the amount is too large, the strength of the film will be reduced. When a film is formed as an antireflection film, the refractive index of the film is preferably 1.20 to 1.45,
It is preferable to select the addition amount of the porous fine particles so that it is more preferably 1.25 to 1.41. The addition amount at that time varies depending on the refractive index of the porous fine particles, but is usually within the range described above, and more preferably 15 to 70% by weight.

The substrate used in the present invention is not particularly limited as long as it is transparent, but for example, polymethylmethacrylate resin, polycarbonate resin, polystyrene, methylmethacrylate-styrene copolymer resin, acrylonitrile-styrene copolymer resin. Resin base materials such as triacetyl cellulose resin, and inorganic base materials such as inorganic glass. In particular, methyl methacrylate-
The styrene copolymer has a small expansion and contraction due to moisture absorption and is suitable as a base material of an antireflection plate.

The substrate may have a flat surface such as a plate (sheet) or film, or may have a curved surface such as a convex lens or a concave lens. . In addition, fine irregularities may be provided on the surface. In the case of a resin base material, another coating such as a hard coat layer may be formed on the surface thereof.

In order to apply a composition containing a cationically polymerizable compound, a hydrolyzable organosilicon compound and porous fine particles onto a substrate, it is necessary to form a coating composition containing each of these components. In general, the coating material contains a polymerization initiator, a catalyst, a solvent and, if necessary, various additives in addition to the cationically polymerizable compound, the hydrolyzable organosilicon compound and the porous fine particles.

The polymerization initiator is necessary for forming a cured film. As the polymerization initiator of the cationically polymerizable compound, a compound that generates a cation when irradiated with ultraviolet rays is used. As such an initiator, for example, onium salts represented by the following formulas, such as diazonium salts, sulfonium salts, and iodonium salts, are preferably used.

ArN ₂ ⁺ Z ⁻ , (R) ₃ S ⁺ Z ⁻ , (R) ₂
I ⁺ Z ^-

In the formula, Ar represents an aryl group, R represents an aryl group or an alkyl group having 1 to 20 carbon atoms, and when R appears a plurality of times in one molecule, they may be the same or different, Z ⁻ represents a non-basic and non-nucleophilic anion.

In each of the above formulas, the aryl group represented by Ar or R is also typically phenyl or naphthyl,
These may be substituted with a suitable group. In addition, Z ^-
Specific examples of the anion represented by: tetrafluoroborate ion (BF ₄ ⁻ ), tetrakis (pentafluorophenyl) borate ion (B (C ₆ F ₅ ) ₄ ⁻ ), hexafluorophosphate ion (PF ₆ ^−). ), Hexafluoroarsenate ion (AsF ₆ ⁻ ), hexafluoroantimonate ion (SbF ₆ ⁻ ), hexachloroantimonate ion (SbCl ₆ ⁻ ), hydrogen sulfate ion (HS
O ₄ ⁻ ), perchlorate ion (ClO ₄ ⁻ ), and the like.

Since many of these cationic polymerization initiators are commercially available, such commercially available products can be used. Examples of commercially available cationic polymerization initiators include “Cyracure” sold by Dow Chemical Japan Co., Ltd.
"UVI-6990", "Adeka Optomer SP-150" and "Adeka Optomer SP-170" sold by Asahi Denka Kogyo Co., Ltd., "RHODORSILPHOTOINITIATOR 2074" sold by Rhodia Japan KK, etc. Can be mentioned.

The initiator is usually added in an amount of about 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the cationically polymerizable compound. When the amount of the initiator is too small, the ultraviolet polymerizable property of the cationically polymerizable compound is not sufficiently exhibited, and even when the amount is too large, the amount increasing effect is not recognized, which is economically disadvantageous and the coating film It is not preferable because it may cause deterioration of optical characteristics.

Further, in order to accelerate the curing of the hydrolyzable organosilicon compound, a curing catalyst such as an acid, an organometallic compound or a metal ion may be contained.

The solvent is used for adjusting the concentration and viscosity of the coating material, the film thickness after curing, and the like. The solvent used may be appropriately selected, for example, methanol, ethanol,
Propanol, isopropanol, n-butanol, 2
-Alcohols such as butanol, isobutanol, tert-butanol, alkoxy alcohols such as 2-ethoxyethanol, 2-butoxyethanol, 3-methoxypropanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol , Ketols such as diacetone alcohol, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate and butyl acetate, etc. .
The amount of the solvent used is appropriately selected according to the material of the substrate, the shape, the coating method, the film thickness of the target coating, etc., but is usually a cationically polymerizable compound, a hydrolyzable organosilicon compound and a porous material. 20 to about 100 parts by weight in total of fine particles
It is in the range of about 10,000 parts by weight.

Further, the coating material may contain additives such as a stabilizer, an antioxidant, a coloring agent and a leveling agent. In particular, silicone oil is effective in improving not only the leveling property but also the slipperiness of the surface of the cured film and the surface hardness, and therefore it is preferably added.

As the silicone oil, usual ones can be used, and specifically, dimethyl silicone oil, phenylmethyl silicone oil, alkyl / aralkyl modified silicone oil, fluorosilicone oil, polyether modified silicone oil, fatty acid ester modified silicone. Oil, methyl hydrogen silicone oil, silanol group-containing silicone oil, alkoxy group-containing silicone oil, phenol group-containing silicone oil, methacryl-modified silicone oil, amino-modified silicone oil, carboxylic acid-modified silicone oil, carbinol-modified silicone oil, epoxy-modified silicone Examples thereof include oil, mercapto-modified silicone oil, fluorine-modified silicone oil, and polyether-modified silicone oil. These silicone oils may be used alone or in combination of two or more. The amount of silicone oil added is usually a cationically polymerizable compound,
Total of hydrolyzable organosilicon compound and porous fine particles 1
It is 0 to 20 parts by weight with respect to 00 parts by weight. The amount is 2
If the amount is more than 0 parts by weight, the optical performance and the film strength are deteriorated, which is not preferable.

By coating the surface of the substrate with the coating material as described above, a coating film composed of the cationically polymerizable compound, the hydrolyzable organosilicon compound and the porous fine particles is formed. In applying the coating material to the surface of the substrate, the same method as usual, for example, microgravure coating method,
Roll coating method, dipping coating method, flow coating method, spin coating method, die coating method, cast transfer method,
It may be applied by a method such as a spray coating method.

Next, this coating is cured by irradiation with ultraviolet rays and heating. When the paint contains a solvent, curing may be carried out while the film contains the solvent,
You may carry out after volatilizing a solvent. When the solvent is volatilized, it may be left at room temperature or may be dried by heating at about 30 to 100 ° C. The drying time is appropriately selected according to the material and shape of the base material, the coating method, the desired film thickness of the coating film, and the like. Either the heat curing or the UV curing may be performed first, or the heat curing may be performed before or after the UV irradiation, such as performing the heat curing and the UV irradiation in this order, and then further heating. .

In the curing of the coating film by heating, the heating temperature and the heating time are not particularly limited, but usually a temperature range of 50 to 120 ° C. for about 1 minute to 5 hours is applied. When the coating material contains a solvent, the heat curing may be carried out while the coating film contains the solvent, or after the solvent is volatilized.

The irradiation time of ultraviolet rays in the ultraviolet irradiation is not particularly limited, but is usually in the range of about 0.1 to 60 seconds. Ultraviolet rays can be usually irradiated in an atmosphere of about 10 to 40 ° C. The irradiation energy of ultraviolet rays to be irradiated is usually about 50 to 3,000 mJ / cm ² . If the irradiation amount of ultraviolet rays is too small, curing will be insufficient and the strength of the film will decrease. On the other hand, if the irradiation amount of ultraviolet rays is too large, the coating film or the base material may be deteriorated and the optical characteristics and mechanical properties may be deteriorated, which is not preferable.

After the cured film is formed by irradiation with ultraviolet rays, if the heat curing treatment is not performed before that, even if the heat curing treatment is performed here, or even if the heat curing is performed before the ultraviolet ray irradiation. A heat curing treatment may be further performed here. The heating temperature and time in this case are appropriately selected, but are usually about 50 minutes to 120 ° C. and about 30 minutes to 24 hours.

The cured film formed usually has a thickness of 0.0.
It is preferable that the thickness is in the range of 1 to 1 μm. If the film thickness is less than 0.01 μm or more than 1 μm, the function as an antireflection film is likely to deteriorate.

[0054]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. In the examples,% and parts indicating the content or the amount used are based on weight unless otherwise specified. The reflectance of the base material obtained in each example was evaluated by the following method.

[Method of Measuring Reflectance] The surface of the base material opposite to the measurement surface side is roughened with steel wool, coated with black paint and dried, and then absolute specular reflection at an incident angle of 5 ° on the measurement surface. Spectra for UV-Visible Spectrophotometer ["UV-3
100 ", manufactured by Shimadzu Corporation], and the wavelength at which the reflectance is minimum and the minimum value of the reflectance were obtained.

Example 1 80 parts of a sol in which 20% of a porous silica fine particle having a particle size of 20 to 70 nm, the surface of which was coated with a hydrolyzate of ethyl silicate, was dispersed in isopropyl alcohol, and 3-ethyl-as an oxetane compound was used. 3-[{3- (triethoxysilyl) propoxy} methyl] oxetane [in formula (III), R ¹ = ethyl, R ⁴ = ethoxy, n = 3, p = 0
[Compound of], 12 parts of oxetanyl silsesquioxane, which is a hydrolyzed condensate, and a photocationic polymerization initiator “RHODOR
SIL PHOTOINITIATOR 2074 "[Chemical name: p-cumyl-p
-Tolyliodonium tetrakis (pentafluorophenyl) borate, obtained from Rhodia Japan Ltd.], 1.5 parts, 12 parts of tetraethoxysilane as a hydrolyzable organosilicon compound, and 12 parts of 0.1N-hydrochloric acid.
Part, methyl hydrogen silicone oil "KF99"
1.5 parts (obtained from Shin-Etsu Chemical Co., Ltd.), 1,681 parts of isopropyl alcohol, and 200 parts of 2-butoxyethanol were mixed and dispersed to obtain a paint.

A methylmethacrylate-styrene copolymer resin plate ["Acryace MS" manufactured by Nippon Acreace Co., Ltd.] containing about 40% of styrene units was dipped in this coating material and dip-coated at a pulling speed of 24 cm / min. After drying at room temperature for 5 minutes or more, heat treatment was performed at 80 ° C. for 20 minutes. Then, a high pressure mercury lamp [“UVC-3533” manufactured by USHIO INC.] Was irradiated with ultraviolet rays at an energy of about 1,000 mJ / cm ² to obtain a transparent substrate having antireflection properties. The evaluation results of this transparent substrate are shown in Table 1. With respect to the coating film of this substrate, the refractive index calculated from the reflection spectrum was 1.38, and the film thickness similarly calculated from the reflection spectrum was 112 nm. This base material was less colored by the reflected light due to the interference color.

Example 2 A transparent base material having antireflection performance was produced in the same manner as in Example 1 except that the composition of the coating material was changed as follows.

[0059] 120 parts of 20% sol of the same porous silica fine particles as in Example 1 8 parts of the same oxetane compound as in Example 1 1.5 parts of the same cationic photopolymerization initiator as in Example 1 Tetraethoxysilane 8 parts 0.1 N-hydrochloric acid 8 parts 1.5 parts of the same silicone oil as in Example 1 Isopropyl alcohol 1,653 parts 2-Butoxyethanol 200 parts

Table 1 shows the evaluation results of the obtained transparent substrate. With respect to the coating film of this substrate, the refractive index calculated from the reflection spectrum was 1.34, and the film thickness calculated from the reflection spectrum was 108 nm. This substrate was also less colored by the reflected light due to the interference color.

[0061]

[Table 1]

[0062]

The transparent substrate having the cured coating of the present invention is
It has excellent anti-reflection properties and little coloring due to interference of reflected light, and is useful as a protective plate for displays and the like.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02B 1/11 G02B 1/10 A F term (reference) 2K009 AA04 BB02 BB13 BB24 CC09 CC33 CC42 DD02 DD05 DD06 4F100 AA20B AA20H AA33B AA33H AH06B AK01B AK12 AK25 AK53B AK80B AL01 AL05B AT00A BA02 DE10B EH46 EH462 EJ42 DLEJ01 NA02 DL08 DL01 DL01NA01 BN01B001BJ0101002BJ0101002BJ0101002BJ0101002BJ0101002BJ0101002BJ01JB06BJ01JN06BBN18B4

Claims (6)

[Claims] 1. A transparent substrate having a cured coating formed from a composition containing a cationically polymerizable compound, a hydrolyzable organosilicon compound and porous fine particles on the surface of the substrate. 2. The transparent substrate according to claim 1, wherein the cationically polymerizable compound is selected from an oxetane compound and an epoxy compound. 3. The transparent substrate according to claim 2, wherein the cationically polymerizable compound contains an oxetane compound having a silyl group in the molecule or a hydrolyzed condensate thereof as a main component. 4. The transparent substrate according to claim 1, wherein the porous fine particles are silica fine particles. 5. The transparent substrate according to claim 1, wherein the porous fine particles are silica or a complex oxide containing silica having a double structure whose surface is coated. 6. The cured film as claimed in claim 1, which has a refractive index of 1.20 to 1.45 and a film thickness of 0.01 to 1 μm and has an antireflection function. Transparent substrate.