WO2006049487A1

WO2006049487A1 - Curable composition, cured product, and laminate

Info

Publication number: WO2006049487A1
Application number: PCT/NL2005/000666
Authority: WO
Inventors: Ryousuke Iinuma; Yasunobu Suzuki; Noriyasu Shinohara; Takayoshi Tanabe
Original assignee: Jsr Corporation
Priority date: 2004-09-22
Filing date: 2005-09-13
Publication date: 2006-05-11
Also published as: KR20070053290A; KR101273731B1

Abstract

The curable composition exhibiting excellent applicability and capable of forming a coating having high hardness, low curling properties, and excellent flexibility on the surface of a substrate, and a cured film including a cured product of the composition. The curable composition, comprises (A) 5 to 70 wt% of metal oxide to which an organic compound containing a polymerizable unsaturated group is bonded; and (B) 20 to 50 wt% of a compound shown by the following formula (I), the amount of each component being based on the total amount of the composition excluding a solvent, Formula (I) wherein R1, R2, and R3 individually represent monovalent organic groups, with at least two of R1, R2, and R3 being -R4OCOCR5=CH2, R4 represents a divalent organic group having 2 to 8 carbon atoms, and R5 represents a hydrogen atom or a methyl group.

Description

CURABLE COMPOSITION, CURED PRODUCT, AND LAMINATE

The present invention relates to a curable composition, a cured product of the curable composition, and a laminate. More particularly, the present invention relates to a curable composition exhibiting excellent applicability and which is capable of forming a coating (film) having high hardness and exhibiting excellent scratch resistance and adhesion to the adjacent layer such as a substrate or a high- refractive-index layer on the surface of a substrate such as plastic (e.g. polycarbonate, polymethyl methacrylate, polystyrene, polyester, polyolefin, epoxy resin, melamine resin, triacetyl cellulose resin, ABS resin, AS resin, and norbornene resin), metal, wood, paper, glass, and slate, and to a hard-coating cured film showing only a small amount of curling and exhibiting excellent flexibility and chemical resistance. In recent years, a curable composition exhibiting excellent applicability and capable of forming a cured film excelling in hardness, flexibility, scratch resistance, abrasion resistance, low curling properties (cured film shows only a small amount of warping), adhesion, transparency, chemical resistance, and appearance on a substrate has been demanded as a protective coating material for preventing scratches or stains on the surface of a substrate; an adhesive or a sealing material for a substrate; and a binder material for printing ink.

In antireflective film applications such as for film-type liquid crystal elements, touch panels, or plastic optical parts, a curable composition capable of forming a cured film having a high refractive index has been demanded. For example, a technology of using a composition containing particles obtained by modifying the surface of colloidal silica with methacryloxysilane and an acrylate as a radiation (photo) curable coating material is proposed in Published Japanese Translation of PCT International Publication No. 58-500251. This type of radiation curable composition has been widely used due to excellent applicability and the like as for example disclosed in Japanese Patent Application Laid-open No. 10-273595, Japanese Patent Application Laid-open No. 2000-143924, Japanese Patent Application Laid-open No. 2000-281863, Japanese Patent Application Laid-open No. 2000-49077, Japanese Patent Application Laid-open No. 2001-89535 or Japanese Patent Application Laid-open No. 2001-200023 Problems to be Solved by the Invention

However, when applying a layer of a low-refractive-index film onto a cured product of the above-mentioned composition and using the resulting laminate as an antireflective film, although the antireflective effect is improved to some extent , there is a need to a further improved antireflective film having well-balanced hardness, flexibility, and curling properties.

The present invention has been achieved in view of the above- described problems. An objective of the present invention is to provide a curable composition having excellent applicability which is capable of forming a coating (film) having high hardness, high flexibility, and low curling properties on the surface of various substrates, and a hard-coat cured film excelling in chemical resistance.

Means for Solving the Problems

According to the present invention, the following curable composition, cured product, and a laminate is provided:

A curable composition, comprising: (A) 5 to 70 wt% of metal oxide particles to which an organic compound containing a polymerizable unsaturated group is bonded; and (B) 20 to 50 wt% of a compound shown by the following formula (1), the amount of each component being based on the total amount of the composition excluding a solvent,

wherein R¹, R², and R³ individually represent monovalent organic groups, with at least two of R¹, R², and R³ being -R⁴OCOCR⁵=CH_2l R⁴ represents a divalent organic group having 2 to 8 carbon atoms, and R⁵ represents a hydrogen atom or a methyl group.

Effect of the Invention

According to the present invention, a curable composition exhibiting excellent applicability and capable of forming a coating having high hardness, low curling properties, and excellent flexibility on the surface of a substrate, and a cured film including a cured product of the composition can be provided. Best Mode for Carrying out the Invention

Embodiments of the curable composition, the cured product of the curable composition, and the laminate of the present invention are described below in detail.

I. Curable composition

The curable composition of the present invention includes (A) 5 to 70 wt% of metal oxide particles to which an organic compound including a polymerizable unsaturated group is bonded; and (B) 20 to 50 wt% of a compound including a structure shown by the formula (1), the amount of each component being based on the total of the composition, excluding a solvent,

wherein R¹, R², and R³ individually represent monovalent organic groups, with at least two of R¹ to R³ being -R⁴OCOCR⁵=CH₂, R⁴ represents an ethylene residue or a propylene residue, R⁵ represents a hydrogen atom or a methyl group, and n represents an integer of 2 to 8. Each component of the curable composition of the present invention is described below in detail.

1. Metal oxide particles (A) to which organic compound having polymerizable unsaturated group is bonded

The component (A) used in the present invention is particles prepared by bonding (Aa) metal oxide particles and (Ab) an organic compound having a polymerizable unsaturated group (hereinafter referred to as "reactive particles"). The components (Aa) and (Ab) may be bonded through a covalent bond or a noncovalent bond such as by physical adsorption.

M^ Metal Oxide particles (Aa^ There are no specific limitations to the metal oxide particles (Aa) used in the present invention. From the viewpoint of hardness and colorlessness of a cured film of the resulting curable composition, the metal oxide particle (Aa) is preferably a metal oxide particle of at least one element selected from the group consisting of silicon, aluminum, zirconium, titanium, zinc, germanium, indium, tin, antimony, and cerium.

As examples of the metal oxide particles (Aa), silica particles, alumina particles, zirconia particles, titanium oxide particles, zinc oxide particles, germanium oxide particles, indium oxide particles, tin oxide particles, antimony tin oxide (ATO) particles, indium tin oxide (ITO) particles, antimony oxide particles, cerium oxide particles, and the like can be given. Of these, silica particles, alumina particles, zirconia particles, and antimony oxide particles are preferable from the viewpoint of high hardness, with silica particles being particularly preferable. A high-refractive-index cured film may be obtained by using oxide particles of zirconium or titanium. A cured film may be provided with electrical conductivity by using ATO particles or the like. These particles may be used either individually or in combination of two or more. It is preferable that the oxide particles (Aa) be in the form of powder or dispersed in a liquid. When using the oxide particles (Aa) in the form of a liquid dispersion, the dispersion medium is preferably an organic solvent from the viewpoint of miscibility with other components and dispersibility. As examples of the organic solvent, alcohols such as methanol, ethanol, isopropanol, butanol, and octanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate; ethers such as ethylene glycol monomethyl ether and diethylene glycol monobutyl ether; aromatic hydrocarbons such as benzene, toluene, and xylene; amides such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; and the like can be given. In particular, methanol, isopropanol, butanol, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, toluene, and xylene are preferable. The number average particle diameter of the metal oxide particles

(Aa) measured by electron microscopy is preferably 0.001 to 2 μm, still more preferably 0.001 to 0.2 μm, and particularly preferably 0.001 to 0.1 μm. If the number average particle diameter exceeds 2 μm, transparency of the resulting cured product may be decreased or the surface state of the resulting film may be impaired. Various surfactants and amines may be added in order to improve the dispersibility of the particles.

As commercially available products of colloidal silica (silica particles), Methanol Silica SoI, IPA-ST, MEK-ST, NBA-ST, XBA-ST, DMAC-ST, ST-UP, ST-OUP, ST-20, ST-40, ST-C, ST-N, ST-O, ST-50, ST-OL, (manufactured by Nissan Chemical Industries, Ltd.), and the like can be given. As commercially available products of powdered silica, Aerosil 130, Aerosil 300, Aerosil 380, Aerosil TT600, Aerosil OX50 (manufactured by Nippon Aerosil Co., Ltd.), Sildex H31 , H32, H51 , H52, H121 , H122 (manufactured by Asahi Glass Co., Ltd.), E220A, E220 (manufactured by Nippon Silica Industrial Co., Ltd.), Sylysia 470 (manufactured by Fuji Silysia Chemical, Ltd.), SG Flake (manufactured by Nippon Sheet Glass Co., Ltd.), and the like can be given.

An aqueous dispersion product of alumina is commercially available as Alumina SoM 00, Sol-200, Sol-520 (manufactured by Nissan Chemical Industries, Ltd.); an isopropanol dispersion product of alumina is commercially available as AS- 1501 (manufactured by Sumitomo Osaka Cement Co., Ltd.); a toluene dispersion product of alumina is commercially available as AS-150T (manufactured by Sumitomo Osaka Cement Co., Ltd.); a toluene dispersion product of zirconia is commercially available as HXU-11OJC (manufactured by Sumitomo Osaka Cement Co., Ltd.); an aqueous dispersion product of zinc antimonate powder is commercially available as Celnax (manufactured by Nissan Chemical Industries, Ltd.); a powder or solvent dispersion product of alumina is commercially available as titanium oxide, tin oxide, indium oxide, zinc oxide, etc., is commercially available as NanoTek (manufactured by C.I. Kasei Co., Ltd.); an aqueous dispersion sol of antimony tin oxide is commercially available as SN-100D (manufactured by lshihara Sangyo Kaisha, Ltd.); ITO powder is commercially available from Mitsubishi Materials Corporation; and an aqueous dispersion product of cerium oxide is commercially available as Needral (manufactured by Taki Chemical Co., Ltd.).

The shape of the metal oxide particle (Aa) may be globular, hollow, porous, rod-like, plate-like, fibrous, or amorphous. The metal oxide particle (Aa) is preferably globular. The specific surface area of the metal oxide particles (Aa) (determined by BET method using nitrogen) is preferably 10 to 1000 m²/g, and still more preferably 100 to 500 m²/g. The metal oxide particles (Aa) may be used in the form of dry powder or a dispersion in water or an organic solvent. As the liquid dispersion of the metal oxide particles (Aa), a liquid dispersion of fine metal oxide particles known in the art may be used. In applications in which excellent transparency is required for the resulting cured product, it is preferable to use a liquid dispersion of the metal oxide particles.

(2) Organic compound (Ab)

The organic compound (Ab) used in the present invention is a compound having a polymerizable unsaturated group. The organic compound (Ab) preferably further contains a group shown by the following formula (2). The organic compound (Ab) preferably contains a group [-O-C(=O)-NH-] and at least one of groups [-O-C(=S)-NH-] and [-S-C(=O)-NH-]. The organic compound (Ab) is preferably a compound having a silanol group in the molecule or a compound which forms a silanol group by hydrolysis.

— U-C-N- (2)

Il V

wherein U represents NH, O (oxygen atom), or S (sulfur atom), and V represents O or S.

(1) Polvmerizable unsaturated group

There are no specific limitations to the polymerizable unsaturated group included in the organic compound (Ab). As preferable examples of the polymerizable unsaturated group, an acryloyl group, methacryloyl group, vinyl group, propenyl group, butadienyl group, styryl group, ethynyl group, cinnamoyl group, maleate group, and acrylamide group can be given.

The polymerizable unsaturated group is a structural unit which undergoes addition polymerization in the presence of active radical species.

(ii) Group shown by formula (2)

The group [-U-C (=V)-NH-] included in the organic compound and shown by the formula (2) is [-O-C(=O)-NH-], [-O-C(=S)-NH-], [-S-C(=O)-NH-], [-NH- C(=O)-NH-], [-NH-C(=S)-NH-], or [-S-C(=S)-NH-]. These groups may be used either individually or in combination of two or more. In particular, it is preferable to use the group [-O-C(=O)-NH-] and at least one of the groups [-O-C(=S)-NH-] and [-S-C(=O)- NH-] in combination from the viewpoint of thermal stability.

It is presumed that the group [-U-C(=V)-NH-] shown by the formula

(2) causes a moderate cohesive force to occur between the molecules due to a hydrogen bond to provide the resulting cured product with excellent mechanical strength, adhesion to a substrate or an adjacent layer such as a high-refractive-index layer, heat resistance, and the like.

(iii) Silanol group or group which forms silanol group by hydrolysis

The organic compound (Ab) is preferably a compound having a silanol group in the molecule or a compound which forms a silanol group by hydrolysis. As such a silanol group-forming compound, a compound in which an alkoxy group, aryloxy group, acetoxy group, amino group, halogen atom, or the like is bonded to a silicon atom can be given. In particular, a compound in which an alkoxy group or an aryloxy group is bonded to a silicon atom, specifically, a compound containing an alkoxysilyl group or a compound containing an aryloxysilyl group is preferable.

A silanol group or a silanol group-forming site of the silanol group- forming compound is a structural unit which bonds to the oxide particles (Aa) by condensation or condensation occurring after hydrolysis.

(iv) Preferable embodiment

As a preferable example of the organic compound (Ab), a compound shown by the following formula (3) can be given.

In the formula (3), R⁶ and R⁷ individually represent a hydrogen atom or an alkyl group or aryl group having 1 to 8 carbon atoms, such as a methyl group, ethyl group, propyl group, butyl group, octyl group, phenyl group, or xylyl group, j represents an integer from 1 to 3.

As examples of the group shown by [(R⁶O)_jR⁷ ₃._jSi-], a trimethoxysilyl group, triethoxysilyl group, triphenoxysilyl group, methyldimethoxysilyl group, dimethylmethoxysilyl group, and the like can be given. Of these, a trimethoxysilyl group or a triethoxysilyl group is preferable.

R⁸ represents a divalent organic group having an aliphatic or aromatic structure having 1 to 12 carbon atoms, and may include a linear, branched, or cyclic structure. As specific examples of such an organic group, methylene, ethylene, propylene, butylene, hexamethylene, cyclohexylene, phenylene, xylylene, dodecamethylene, and the like can be given.

R⁹ represents a divalent organic group selected from divalent organic groups having a molecular weight of 14 to 10,000, and preferably 76 to 500. As specific examples of such an organic group, a linear polyalkylene group such as hexamethylene, octamethylene, and dodecamethylene; a divalent alicyclic or polycyclic organic group such as cyclohexylene and norbornylene; a divalent aromatic group such as phenylene, naphthylene, biphenylene, and polyphenylene; and alkyl- or aryl- substituted products of these groups can be given. These divalent organic groups may include an atomic group containing an element other than a carbon atom and a hydrogen atom, and may include a polyether bond, polyester bond, polyamide bond, or polycarbonate bond.

R¹⁰ represents an organic group with a valence of (k+1), and is preferably selected from linear, branched, or cyclic saturated or unsaturated hydrocarbon groups.

Z represents a monovalent organic group containing a polymerizable unsaturated group which undergoes an intermolecular crosslinking reaction in the presence of active radical species in the molecule, k represents an integer preferably from 1 to 20, more preferably from 1 to 10, and particularly preferably from 1 to 5. As specific examples of the compound shown by the formula (3), compounds shown by the following formulas (4-1) and (4-2) can be given.

wherein "Acryl" represents an acryloyl group, and "Me" represents a methyl group.

The organic compound (Ab) used in the present invention may be synthesized by a method disclosed in Japanese Patent Application Laid-open No. 9- 100111 , for example. The organic compound (Ab) is preferably produced by reacting mercaptopropyltrimethoxysilane and isophorone diisocyanate at 60 to 70⁰C for about several hours in the presence of dibutyltin dilaurate, adding pentaerythritol triacrylate to the reaction product, and reacting the mixture at 60 to 7O⁰C for about several hours.

(3) Reactive particles (A)

The organic compound (Ab) having a silanol group or a group which forms a silanol group by hydrolysis is mixed with the metal oxide particles (Aa) and hydrolyzed to bond the metal oxide particles (Aa) and the organic compound (Ab). The amount of the organic polymer component (i.e. hydrolysate and condensate of hydrolysable silane) in the resulting reactive particles (A) may be determined, by thermogravimetric analysis from room temperature to 800⁰C in air, as the constant weight loss (%) when completely burning the dry powder in air, for example.

The amount of the organic compound (Ab) bonded to the oxide particles (Aa) is preferably 0.01 wt% or more, still more preferably 0.1 wt% or more, and particularly preferably 1 wt% or more of 100 wt% of the reactive particles (A) (metal oxide particles (Aa) and organic compound (Ab) in total). If the amount of the organic compound (Ab) bonded to the metal oxide particles (Aa) is less than 0.01 wt%, the dispersibility of the reactive particles (A) in the composition may be insufficient, whereby the resulting cured product may exhibit insufficient transparency and scratch resistance. The amount of the metal oxide particles (Aa) in the raw material when preparing the reactive particles (A) is preferably 5 to 99 wt%, and still more preferably 10 to 98 wt%. The content of the oxide particles (Aa) in the reactive particles (A) is preferably 65 to 90 wt%. The amount (content) of the reactive particles (A) in the curable composition is preferably 5 to 70 wt%, still more preferably 30 to 60 wt%, and particularly preferably 40 to 60 wt%, provided that the total amount of the composition excluding an organic solvent is 100 wt%. If the amount is less than 5 wt%, the hardness of the cured product may be insufficient. If the amount exceeds 70 wt%, film formability may be impaired. The amount of the reactive particles (A) refers to the solid content. When the reactive particles (A) are used in the form of a liquid dispersion, the amount of the reactive particles (A) excludes the amount of the dispersion medium.

2. Compound (B) The compound (B) used in the present invention is a compound shown by the following formula (1).

wherein R¹, R², and R³ individually represent monovalent organic groups, with at least two of R¹, R², and R³ being -R⁴OCOCR⁵=CH₂, R⁴ represents a divalent organic group having 2 to 8 carbon atoms, preferably an organic group having 2 to 4 carbon atoms, and still more preferably -CH₂CH₂-, and R⁵ represents a hydrogen atom or a methyl group. The compound (B) reduces warping of a cured film obtained by curing the composition of the present invention and provides the cured film with flexibility.

As specific examples of the compound (B) which may be used in the present invention, bis((meth)(acryloxymethyl)hydroxymethyl isocyanurate, bis((meth)acryloxyethyl)hydroxyethyl isocyanurate, tris((meth)acryloxymethyl)isocyanurate, tris((meth)acryloxyethyl) isocyanurate, caprolactone-modified tris((meth)acryloxyethyl)isocyanurate, and the like can be given. Of these, bis((meth)acryloxyethyl)hydroxyethyl isocyanurate and tris((meth)acryloxyethyl) isocyanurate are preferable. As commercially available products which may be suitably used as the compound (B), M-215, M-315, M-325 (manufactured by Toagosei Co., Ltd.), TEICA (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), TAIC, TMAIC (manufactured by Nippon Kasei Chemical Co., Ltd.), and the like can be given. These compounds may be used either individually or in combination of two or more. The compound (B) is used in the present invention in an amount of preferably 20 to 50 wt%, and still more preferably 30 to 40 wt% for 100 wt% of the total amount of the composition excluding an organic solvent. If the amount is less than 20 wt%, the resulting cured film may be curled. If the amount exceeds 50 wt%, the hardness of the cured film may be insufficient. The component (B) is used in an amount of preferably 40 wt% or more, still more preferably 50 wt% or more, and particularly preferably 60 wt% or more for 100 wt% of the total (meth)acrylate component in the composition excluding the component (A). If the content of the compound (B) is 40 wt% or more, warping of the resulting cured film can be effectively reduced. The total (meth)acrylate component excluding the component (A) used herein refers to the (meth)acrylate component included in the total soluble component excluding the component (A) which is the insoluble particles. Specifically, the total (meth)acrylate component refers to the total amount of the component (B)₁ component (C), and component (D) (components (C) and (D) are described later).

3. Urethane (meth)acrylate (C)

The composition of the present invention may include (C) a urethane (meth)acrylate, as required. The compound (C) is suitably used to improve the flexibility of the resulting cured film.

There are no specific limitations to the urethane (meth)acrylate (C). The urethane (meth)acrylate (C) is basically obtained by reacting (a) a polyisocyanate compound and (b) a hydroxyl group-containing (meth)acrylate monomer. The urethane (meth)acrylate may be a compound having another oligomer as a main chain to which a (meth)acrylate is bonded via a urethane bond.

The urethane (meth)acrylate has at least two, preferably four or more, and still more preferably six or more (meth)acryloyl groups. Such a urethane (meth)acrylate usually has a structure in which the hydroxyl group-containing (meth)acrylate monomer (b) is bonded to each isocyanate group of the polyisocyanate compound (a) having 2 to 6 isocyanate groups.

A urethane (meth)acrylate shown by the following formula (5) can improve the flexibility and anti-curling properties of the resulting cured film without affecting the hardness of the cured film to a large extent.

( 5) wherein "Acryl" represents an acryloyl group.

The urethane (meth)acrylate (C) used in the present invention may be synthesized, or a commercially available product may be used. The urethane (meth)acrylate (C) is produced as described below. A vessel equipped with a stirrer is charged with a polyisocyanurate compound and dibutyltin dilaurate (0.001 equivalent for one equivalent of isocyanurate group). Then, the reaction solution is cooled to 10 to 15⁰C with stirring. A hydroxyl group-containing (meth)acrylate compound is gradually added to the reaction solution while maintaining the reaction solution at about 5O⁰C or lower. After addition of the hydroxyl group-containing (meth)acrylate compound, the temperature of the reaction solution is raised to 65⁰C, and the reaction solution is stirred for one hour. The reaction solution is subjected to FT-IR measurement, and the reaction is terminated when the residual isocyanurate content becomes 0.2 wt% or less. The polyisocyanurate compound and the hydroxyl group-containing (meth)acrylate monomer are used so that the hydroxyl group of the hydroxyl group-containing (meth)acrylate monomer is 1.0 to 2 equivalents for one equivalent of the isocyanurate group of the polyisocyanurate compound.

As commercially available products of the urethane (meth)acrylate (C), Beamset 102, 502H, 505A-6, 510, 550B, 551 B, 575, 575CB, EM-90, EM92, manufactured by Arakawa Chemical Industries, Ltd.; Photomer 6008 and 6210, manufactured by SAN NOPCO, Ltd.; NK OLIGO U-2PPA, U-4HA, U-6HA, H-15HA, UA-32PA, U-324A, U-4H, and U-6H, manufactured by Shin-Nakamura Chemical Co., Ltd.; Aronix M-1100, M-1200, M-1210, M-1310, M-1600, and M-1960, manufactured by Toagosei Co., Ltd.; AH-600, AT606, and UA-306H, manufactured by Kyoeisha Chemical Co., Ltd.; Kayarad UX-2201 , UX-2301 , UX-3204, UX-3301 , UX-4101 , UX- 6101 , and UX-7101 , manufactured by Nippon Kayaku Co., Ltd.; UV-1700B, UV-3000B, UV-6100B, UV-6300B, UV-7000, and UV-2010B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.; Artresin UN-1255, UN-5200, HDP-4T, HMP-2, UN-901T, UN-3320HA, UN-3320HB, UN-3320HC, UN-3320HS, H-61, and HDP-M20, manufactured by Negami Chemical Industrial Co., Ltd.; Ebecryl 6700, 204, 205, 220, 254, 1259, 1290K, 1748, 2002, 2220, 4833, 4842, 4866, 5129, 6602, and 8301 , manufactured by Daicel UBC Co Ltd.; and the like can be given. Of these, U-6HA is preferable as a urethane (meth)acrylate having three or more (meth)acrylate groups. The compound (C) is used in the present invention in an amount of preferably 5 to 20 wt%, and still more preferably 5 to 10 wt% for 100 wt% of the total amount of the composition excluding an organic solvent. If the amount exceeds 20 wt%, the hardness of the resulting cured film may be insufficient.

4. Polvfunctional (meth)acrylate compound (D) The composition of the present invention may include (D) a polyfunctional (meth)acrylate, as required. The polyfunctional (meth)acrylate compound (D) is a (meth)acrylate monomer containing two or more polymerizable unsaturated groups in the molecule, and is a component other than the components (A), (B), and (C). The polyfunctional (meth)acrylate compound is suitably used to improve the curability and hardness of the resulting cured film. The expression "polyfunctional" used herein means that the (meth)acrylate compound contains two or more (meth)acryloyl groups in the molecule. From a viewpoint of film formability and hardness, a tri- or higher functional (meth)acrylate compound is preferable, with a penta- or higher functional (meth)acrylate compound being still more preferable . As preferable examples of the polyfunctional (meth)acrylate compound (D), dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, and the like can be given.

The polyfunctional (meth)acrylate compound (D) may be synthesized, or a commercially available product may be used. The polyfunctional (meth)acrylate is produced as described below.

The polyfunctional (meth)acrylate compound is commercially available as Kayarad DPHA (manufactured by Nippon Kayaku Co., Ltd.), and the like. The compound (D) is used in the present invention in an amount of preferably 5 to 20 wt%, and still more preferably 10 to 20 wt% for 100 wt% of the total amount of the composition excluding an organic solvent. If the amount exceeds 20 wt%, flexibility and anti-curling properties of the resulting cured film may be insufficient. If the amount is less than 10 wt%, the cured film may exhibit insufficient hardness.

5. Radical polymerization initiator (E) The composition of the present invention may include (E) a radical polymerization initiator, as required.

As examples of the radical polymerization initiator (E), a compound which thermally generates active radical species (heat polymerization initiator) and a compound which generates active radical species upon application of radiation (light) (radiation (photo) polymerization initiator) can be given. There are no specific limitations to the radiation (photo) polymerization initiator insofar as the initiator decomposes upon irradiation and generates radicals to initiate polymerization. Examples of the radiation (photo) polymerization initiator include acetophenone, acetophenone benzyl ketal, 1- hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1 ,2-diphenylethan-1-one, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3- methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'- diaminobenzophenone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2- methylpropan-1-one, 2-hydroxy-2-methyl-1- phenylpropan-1-one, thioxanethone, diethylthioxanthone, 2-isopropylthioxanthone, 2- chlorothioxanthone, 2-methyl~1 -[4-(methylthio)phenyl]-2-morpholino-propan-1 -one, 2- benzyl-2-dimethyIamino-1-(4-morpholinophenyl)-butanone-1,4-(2- hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone), and the like.

As commercially available products of the radiation (photo) polymerization initiator, lrgacure 184, 369, 651, 500, 819, 907, 784, 2959, CG11700, CGI1750, CGI1850, CG24-61 , Darocur 1116, 1173 (manufactured by Ciba Specialty Chemicals Inc.), Lucirin TPO (manufactured by BASF), Ebecryl P36 (manufactured by UCB), Esacure KIP150, KIP65LT, KIP100F, KT37, KT55, KTO46, KIP75/B (manufactured by Lamberti), and the like can be given.

The radical polymerization initiator (E), which is used in the present invention as an optional component, is used in an amount of preferably 0.01 to 20 wt%, and still more preferably 0.1 to 10 wt% for 100 wt% of the total amount of the composition excluding an organic solvent. If the amount is less than 0.01 wt%, the resulting cured product may exhibit insufficient hardness. If the amount exceeds 20 wt%, the inside (lower layer) of the cured product may remain uncured.

When curing the composition of the present invention, a photoinitiator and a heat polymerization initiator may be used in combination, as required. As preferable examples of the heat polymerization initiator, peroxides and azo compounds can be given. Specific examples include benzoyl peroxide, t-butyl peroxybenzoate, azobisisobutyronitrile, and the like.

6. Organic solvent (F) The composition of the present invention may be diluted with an organic solvent (F) in order to adjust the thickness of a coating formed by using the composition. When using the composition as an antireflective film or a coating material, the viscosity of the composition is usually 0.1 to 50,000 mPa s/25°C, and preferably 0.5 to 10,000 mPa-s/25°C. There are no specific limitations to the organic solvent (F). However, since the compound used as the component (B) has high crystallinity, it is preferable to used a high-boiling solvent so that the composition of the present invention is uniformly applied. As specific examples of the organic solvent (F), alcohols such as methanol, ethanol, isopropanol, butanol, and octanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate; ethers such as ethylene glycol monomethyl ether and diethylene glycol monobutyl ether; aromatic hydrocarbons such as benzene, toluene, and xylene; amides such as dimethylformamide, dimethylacetamide, and N- methylpyrrolidone; and the like can be given. Of these, high-boiling solvents such as methyl isobutyl ketone, cyclohexanone, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, toluene, and xylene are preferable.

The organic solvent (F) is used in the composition of the present invention in an amount of usually 30 to 80 wt%, and preferably 40 to 60 wt% of the total amount of the composition. If the amount of the organic solvent (F) is in the range of 30 to 80 wt%, the composition exhibits excellent applicability.

7. Other components

The curable composition of the present invention may include a photosensitizer, polymerization inhibitor, polymerization adjuvant, leveling agent, wettability improver, surfactant, plasticizer, UV absorber, antioxidant, antistatic agent, inorganic filler, pigment, and dye, and the like insofar as the effects of the present invention are not impaired.

8. Preparation of composition The composition of the present invention is produced as follows.

A reaction vessel equipped with a stirrer is charged with the reactive particle liquid dispersion, radiation (photo) polymerization initiator, polyfunctional (meth)acrylate, and urethane (meth)acrylate. The mixture is stirred at 35 to 45⁰C for two hours to obtain the composition of the present invention. When replacing the solvent with a solvent (B) differing from a solvent (A) used in the reactive particle liquid dispersion, the solvent (B) is also added to the mixture in an amount 1.3 times the amount of the solvent (A) of the reactive particle liquid dispersion, and the mixture is stirred under the same conditions. Then, the composition solution is concentrated under reduced pressure by using a rotary evaporator until the weight before adding the solvent (B) is reached to obtain the composition of the present invention.

9. Application (coating) of composition

The composition of the present invention is suitable for use as an antireflective film or a coating material. As examples of substrates to which the composition is applied, plastic (e.g. polycarbonate, polymethacrylate, polystyrene, polyester, polyolefin, epoxy resin, melamine resin, triacetyl cellulose resin, ABS resin, AS resin, and norbomene resin), metal, wood, paper, glass, slate, and the like can be given. The substrate may be in the shape of a plate, film, or three-dimensional formed product. As the coating method, an ordinary coating method such as dipping, spray coating, flow coating, shower coating, roll coating, spin coating, brush coating, or the like can be given. The thickness of the coating formed by using such a coating method is usually 0.1 to 400 mm, and preferably 1 to 200 mm after drying and curing.

10. Curing of composition

The composition of the present invention may be cured by applying heat and/or radiation (light). When curing the composition by applying heat, the heat source may be an electric heater, infrared lamp, hot blast, or the like. When curing the composition by applying radiation (light), there are no specific limitations to the radiation source insofar as the composition can be cured in a short period of time after application. As examples of the source of infrared rays, a lamp, resistance heating plate, laser, and the like can be given. As examples of the source of visible rays, sunlight, a lamp, fluorescent lamp, laser, and the like can be given. As examples of the source of ultraviolet rays, a mercury lamp, halide lamp, laser, and the like can be given. As examples of the source of electron beams, a system utilizing thermoelectrons generated from a commercially available tungsten filament, a cold cathode method which generates electron beams by applying a high voltage pulse through a metal, and a secondary electron method which utilizes secondary electrons generated by collision between ionized gaseous molecules and a metal electrode can be given. As examples of the source of α-rays, β-rays, and γ-rays, fissionable substances such as Co⁶⁰ and the like can be given. As the source of α-rays, a vacuum tube which causes accelerated electrons to collide with an anode or the like may be utilized. The radiation may be used either individually or in combination of two or more types. In the latter case, two or more types of radiation may be applied either simultaneously or at certain intervals of time.

The curing reaction of the composition of the present invention may be carried out in air or under anaerobic conditions such as in a nitrogen atmosphere. Even when the composition of the present invention is cured under anaerobic conditions, the resulting cured product exhibits excellent scratch resistance.

II. Cured product

The cured product of the present invention may be obtained by applying the curable composition to various substrates such as a plastic substrate, and curing the applied composition. In more detail, after applying the composition to a substrate, volatile components are dried at a temperature of preferably 0 to 200⁰C, and the composition is cured by applying heat and/or radiation to obtain a coating formed product. When curing the composition by applying heat, the composition is preferably cured at 20 to 15O⁰C for 10 seconds to 24 hours. When curing the composition by applying radiation, it is preferable to use ultraviolet rays or electron beams. In this case, the dose of ultraviolet rays is preferably 0.01 to 10 J/cm², and still more preferably 0.1 to 2 J/cm². Electron beams are preferably applied at an accelerating voltage of 10 to 300 KV, an electron density of 0.02 to 0.30 mA/cm², and a dose of 1 to 10 Mrad.

Since the cured product of the present invention has high hardness, low curling properties, and excellent flexibility and can form a coating (film) exhibiting excellent scratch resistance and excellent adhesion to a substrate or an adjacent layer such as a high-refractive-index layer, the cured product is particularly suitable as an antireflective film for film-type liquid crystal elements, touch panels, plastic optical parts, and the like.

III. Laminate

The invention also relates to a laminate comprising the cured product.

The cured product of the present invention is usually laminated on a substrate as a hard coating layer. A laminate suitable as an antireflective film may be formed by laminating a high-refractive-index layer and a low-refractive-index layer on the cured film (hard coating layer). The antireflective film may further include a layer other than these layers. For example, pairs of a high-refractive-index layer and a low- refractive-index layer may be provided to form a wide-band antireflective film having relatively uniform reflectance characteristics for light over a wide wavelength range. Or₁ an antistatic layer may be provided.

There are no specific limitations to the substrate. When using the laminate as an antireflective film, plastic (e.g. polycarbonate, polymethyl methacrylate, polystyrene, polyester, polyolefin, epoxy resin, melamine resin, triacetyl cellulose resin, ABS resin, AS resin, and norbomene resin) and the like can be given as the material for the substrate.

As examples of the high-refractive-index film used for the laminate of the invention, a film having a refractive index of 1.65 to 2.20, such as a coating material cured film containing metal oxide particles such as zirconia particles, can be given. As examples of the low-refractive-index film used in the present invention, a film having a refractive index of 1.38 to 1.45, such as a metal oxide film or a fluorine-type coating material cured film containing magnesium fluoride or silicon dioxide, can be given.

As a method of forming the low-refractive-index film on the high- refractive-index cured film obtained by curing the curable composition, when forming a metal oxide film, vacuum deposition, sputtering, and the like can be given. When forming a fluorine-type coating material cured film, a method the same as the application (coating) method of the composition can be given.

Reflection of light at the surface of the substrate can be effectively prevented by layering the high-refractive-index cured film and the low-refractive-index film on the substrate.

Since the laminate of the present invention has high hardness, low curling properties, excellent flexibility, low reflectance, and excellent chemical resistance, the laminate is particularly suitably used as an antireflective film for film- type liquid crystal elements, touch panels, plastic optical parts, and the like. Examples

The present invention is described in more detail by way of examples. However, the scope of the present invention is not limited to the description of the following examples. In the examples, "part" refers to "part by weight" and "%" refers to "wt%" unless otherwise indicated. Preparation Example 1 : Preparation of organic compound (Ab) having a polvmerizable unsaturated group

222 parts of isophorone diisocyanate was added dropwise to a solution of 221 parts of mercaptopropyltrimethoxysilane and 1 part of dibutyltin dilaurate in dry air at 5O⁰C in one hour with stirring. The mixture was then stirred at 7O⁰C for three hours. After the dropwise addition of 549 parts of NK Ester A-TMM-3LM- N (manufactured by Shin-Nakamura Chemical Co., Ltd) (consisting of 60 wt% of pentaerythritol triacrylate and 40 wt% of pentaerythritol tetraacrylate; only pentaerythritol triacylate having hydroxyl group takes part in the reaction) at 3O⁰C in one hour, the mixture was stirred at 6O⁰C for ten hours to obtain an organic compound (Ab) having a polymerizable unsaturated group. The residual isocyanate content in the resulting product was analyzed by FT-IR and found to be 0.1% or less. This indicates that the reaction was completed almost quantitatively. In the infrared absorption spectrum of the resulting product, the absorption peak at 2550 kayser characteristic of a mercapto group and the absorption peak at 2260 kayser characteristic of an isocyanate group in the raw material disappeared, and the absorption peak at 1660 kayser characteristic of a urethane bond and a S(C=O)NH- group and the absorption peak at 1720 kayser characteristic of an acryloyl group appeared. This indicates that an acryloxy group-modified alkoxysilane having an acryloxy group, -S(C=O)NH- group, and a urethane bond as polymerizable unsaturated groups was produced. The above reaction yielded 773 parts of compounds shown by the formulas (4-1) and (4-2). The product also contained 220 parts of pentaerythritol tetraacrylate which did not take part in the reaction.

Preparation Example 2: Preparation of urethane (meth)acrylate (C-2)

A vessel equipped with a stirrer was charged with a solution of 18.8 parts of isophorone diisocyanate and 0.2 parts of dibutyltin dilaurate. After the dropwise addition of 93 parts of NK Ester A-TMM-3LM-N (manufactured by Shin-Nakamura Chemical Co., Ltd) (only pentaerythritol triacylate having hydroxyl group takes part in the reaction) at 10⁰C in one hour, the mixture was stirred at 6O⁰C for six hours to obtain a reaction liquid.

The residual isocyanate content in the reaction liquid measured by FT-IR in the same manner as in Preparation Example 1 was 0.1 wt% or less. This indicates that the reaction was completed almost quantitatively. It was confirmed that a urethane bond and an acryloyl group (polymerizable unsaturated group) were included in the molecule.

The above reaction yielded 75 parts of compounds shown by the formula (5). The product also contained 37 parts of pentaerythritol tetraacetate which did not take part in the reaction.

Preparation Example 3: Preparation of silica particle liquid dispersion (i) Preparation of methanol dispersed colloidal silica

A tank was charged with 30 kg of colloidal silica dispersed in water ("Snowtex-O" manufactured by Nissan Chemical Industries, Ltd., solid content: 20 wt%, pH: 2.7, specific surface area measured by BET method: 226 m²/g, silanol group concentration on silica particles determined by methyl red adsorption method: 4.1 x 10^' ⁵ mol/g, metal content in solvent determined by atomic absorption method: Na; 4.6 ppm, Ca; 0.013 ppm, K; 0.011 ppm). The colloidal silica was concentrated at a temperature of 5O⁰C, a circulation flow rate of 50 l/min., and a pressure of 1 kg/cm² using an ultrafilter membrane module (manufactured by Tri Tec Corporation) and an ultrafilter membrane made of alumina ("Ceramic UF Element" manufactured by NGK Insulators, Ltd., specification: 4 mm in diameter, 19 pores, 1 m in length, fractional molecular weight = 150,000, membrane area = 0.24 m²). After 30 minutes, 10 kg of filtrate was discharged to obtain a residue with a solid content of 30 wt%. The average permeation flow rate (membrane permeation weight per unit area of ultrafilter membrane and unit time) before concentration was 90 kg/m²/hour. After concentration, the average permeation flow rate was 55 kg/m²/hour. The number average particle diameter determined by a dynamic light scattering method before and after concentration was 11 nm. After the addition of 14 kg of methanol to the above colloidal silica, the mixture was then concentrated at 5O⁰C at a circulation flow rate of 50 l/min. and pressure of 1 kg/cm² using the above ultrafilter membrane module and ultrafilter membrane to discharge 14 kg of filtrate. This step was repeated six times to prepare 20 kg of colloidal silica dispersed in methanol with a solid content of 30 wt%, water content determined by the Karl Fischer method of 1.5 wt%, and number average particle diameter determined by a dynamic light scattering method of 11 nm. The average permeation flow rate of six times of operation was 60 kg/m²/hour, requiring six hours for the operation to complete. The specific surface area of the resulting colloidal silica dispersed in methanol measured by the BET method was 237 m²/g. The silanol group concentration on the silica particles determined by a methyl red adsorption method was 3.5 x 10^"5 mol/g.

HO Preparation of hydrophobic colloidal silica dispersed in methyl ethyl ketone

0.6 kg of trimethylmethoxysilane (manufactured by Toray-Dow Corning Silicone Co. Ltd.) was added to 20 kg of the colloidal silica dispersed in methanol prepared in the Preparation Example 1. The mixture was then stirred at 60 |O' Q for three hours with heating. The number average particle diameter determined by a dynamic light scattering method was 11 nm which was the same value as that before stirring. The specific surface area of the resulting hydrophobic colloidal silica dispersed in methanol measured by a BET method was 240 m²/g. The silanol group concentration on the silica particles determined by a methyl red adsorption method was 2.1 x 10-⁵ mol/g.

After the addition of 14 kg of methyl ethyl ketone to the above hydrophobic colloidal silica, the mixture was then concentrated at a temperature of 5O⁰C, a circulation flow rate of 50 I/min., and a pressure of 1 kg/cm² using the above ultrafilter membrane module and ultrafilter membrane to discharge 14 kg of filtrate. This step was repeated five times to prepare 20 kg of hydrophobic colloidal silica dispersed in methyl ethyl ketone (silica particle liquid dispersion) with a solid content of 30 wt%, water content determined by the Karl Fischer method of 0.3 wt%, methanol content determined by gas chromatography (GC) of 3.2 wt%, and number average particle diameter determined by a dynamic light scattering method of 11 nm. The average permeation flow rate of five times of operation was 70 kg/m²/hour, which required four hours. The specific surface area of the resulting hydrophobic colloidal silica dispersed in methyl ethyl ketone measured by the BET method was 230 m²/g. The silanol group concentration on the silica particles determined by a methyl red adsorption method was 1.8 x 10^'5 mol/g. The metal content in the solvent of the hydrophobic colloidal silica dispersed in methyl ethyl ketone determined by an atomic absorption method was as low as 0.05 ppm of Na and 0.001 ppm of Ca and K, respectively. Preparation Examples 4: Preparation of reactive silica particle liquid dispersion (A-D A mixture of 2.32 parts of the organic compound (Ab) including a polymerizable unsaturated group prepared in Preparation Example 1, 89.90 parts of a silica particle liquid dispersion (Aa) (silica concentration: 32%) prepared in Preparation Example 3, 0.12 parts of ion-exchanged water, and 0.01 part of p-hydroxyphenyl monomethyl ether was stirred at 6O⁰C for four hours. After the addition of 1.36 part of methyl orthoformate, the mixture was stirred at the same temperature for one hour to obtain reactive particles (liquid dispersion (A-1)). 2 g of the liquid dispersion (A-1) was weighed on an aluminum dish and dried on a hot plate at 175⁰C for one hour. The dried material was weighed and the solid content was found to be 30.7%. 2 g of the liquid dispersion (A-1) was weighed in a magnetic crucible, predried on a hot plate at 8O⁰C for 30 minutes, and sintered at 75O⁰C for one hour in a muffle furnace. The inorganic content in the solid content was determined from the resulting inorganic residue to confirm that the inorganic content was 90%.

Example 1 (1) Preparation of curable composition

176.74 parts of the reactive silica particle liquid dispersion (A-1) prepared in Preparation Example 4 (54.26 parts as reactive particles (A), composed of 48.6 parts of silica particles (Aa) and 5.67 parts of the organic compound (Ab) which bonds to the silica particles, 31.28 parts of tris(acryloxyethyl) isocyanurate (B-1), 6.05 parts of urethane acrylate (C-2) shown by the formula (5), prepared in Preparation Example 2, 4.64 parts of pentaerythritol tetraacrylate (D-2), 2.36 parts of 1- hydroxycyclohexyl phenyl ketone (E-1), 1.41 parts of 2-methyl-1-[4-(methylthio)phenyl]- 2-morpholinopropanone-1 (E-2), and 159.22 parts of methyl isobutyl ketone (MIBK) were stirred at 40⁰C for two hours to obtain a homogeneous solution. The resulting solution was concentrated under reduced pressure by using a rotary evaporator until the amount of the solution became 222.48 parts to replace the solvent mainly with MIBK to obtain a homogeneous composition solution. The pentaerythritol tetra(meth)acrylate (D-2) originates in pentaerythritol tetraacrylate in the organic compound (Ab) and the urethane (meth)acrylate (C-2). The solid content of the composition determined was 45%.

(2) Preparation of antireflective film laminate

The composition obtained in (1) was applied to a substrate using a bar coater so that the thickness after drying was 20 μm. The composition was dried in a hot blast oven at 100⁰C for one minute and then irradiated at a dose of 300 m J/cm² using a conveyer-type mercury lamp to obtain a cured film. Flexibility and anti-curling properties were evaluated using the resulting cured film. The results are shown in Table 1. A cured film with a thickness of 31 μm after drying was formed on a slide using a bar coater in the same manner as described above, and the resulting cured film was subjected to a universal hardness test. A slide with a thickness of 1 mm was used as a substrate in the universal hardness test, and a triacetyl cellulose (TAC) film with a thickness of 81 μm was used as a substrate for evaluating flexibility and anti-curling properties.

Examples 2 to 4 and Comparative Examples 1 and 2

Compositions were prepared in the same manner as in Example 1 except for using the components shown in Table 1.

Evaluation of cured film Evaluation methods for the cured film are given below. The evaluation results are shown in Table 1.

The flexibility, anti-curling properties, and universal hardness of the cured films obtained in Examples 1 to 4 and Comparative examples 1 and 2 were measured or evaluated according to methods given below.

(1) Curling

A cured film formed on a triacetyl cellulose film (15x15 cm) was cut into a square sample with a size of 10x10 cm, and allowed to stand at a temperature of 25⁰C and a humidity of 50% for one hour. The thickness of the cured film was measured using a thickness meter, and a cured film having a thickness of 20±2 μm was subjected to a curling test. In the curling test, the cured film was placed on a glass plate, and the distances between each corner of the cured film and the flass plate was measured using a ruler. The distance was taken as a value of curling. Grade 5: 0 to 5 mm Grade 4: 6 to 10 mm Grade 3: 11 to 15 mm Grade 2: 16 to 20 mm Grade 1 : 21 mm or more

(2) Flexibility The 10x10 cm cured film obtained by the method described in (1) was cut into a strip with a width of 1 cm, and the strip-shaped film was subjected to a flexibility test. The strip-shaped film was slowly wound around a cylinder having a different diameter, and slowly unwound from the cylinder. The minimum diameter at which cracks did not occur in the strip-shaped film was taken as the flexibility value. Grade 3: 1 to 5 mm Grade 2: 6 to 10 mm Grade 1 : 11 mm or more

(3) Universal hardness The thickness of the cured film formed on the slide by the method described in (1) was measured using a DEK-TAK tester ("WIN-HCU" manufactured by Fischer Ltd.). A universal hardness test was conducted at a portion where the thickness of the film was 31 ±2 μm. In the measurement of the universal hardness test, a load of 300 mN/cm² was gradually applied to the film in 60 seconds, and maintained 5 seconds, and gradually reduced in 60 seconds. A Vickers indenter was used as an indenter.

Grade 4: Universal hardness: 370 mN/mm² or more Grade 3: Universal hardness: 351 to 370 mN/mm² Grade 2: Universal hardness: 331 to 350 mN/mm² Grade 1 : Universal hardness: 300 to 330 mN/mm²

[Table 1]

K) Ul

In Table 1 , the amount of the reactive silica particles (A-1) indicates the fine powder dry weight (excluding organic solvent).

The meanings of the abbreviations shown in Table 1 are as follows. A-1 : Reactive silica particles prepared in Preparation Example 4 B-1 : Tris(acryloxyethyl)isocyanurate (manufactured by Toagosei Co., Ltd.) C-1 : U-6HA (manufactured by Shin-Nakamura Chemical Co., Ltd.) C-2: Compound shown by the formula (5) prepared in Preparation Example 2 D-1 : Dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.) D-2: Pentaerythritol tetraacrylate (originates in NK Ester A-TMM-3LM-N manufactured by Shin-Nakamura Chemical Co., Ltd.)

E-1 : 1-Hydroxycyclohexyl phenyl ketone (Irgacure 184; manufactured by Ciba

Specialty Chemicals Inc.) E-2: 2-Methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1 (Irgacure 907; manufactured by Ciba Specialty Chemicals Inc.) MEK: Methyl ethyl ketone MIBK: Methyl isobutyl ketone

From the results shown in Table 1 , the cured product of the curable resin composition of the present invention exhibits well-balanced curling, flexibility and hardness.

Industrial Applicability

As described above, since the curable composition and the cured product of the present invention exhibits high hardness, a small amount of curling and excellent flexibility, the curable composition and the cured product can be suitably used as a protective coating material for preventing occurrence of scratches or stains of plastic optical parts, touch panels, film-type liquid crystal elements, plastic containers, and flooring materials, wall materials, and artificial marbles used as architectural interior finish; an antireflective film for film-type liquid crystal elements, touch panels, or plastic optical parts; an adhesive or a sealing material for various substrates; a binder for printing ink; and the like. The curable composition and the cured product can be particularly suitably used as an antireflective film.

Claims

1. A curable composition, comprising:

(A) 5 to 70 wt% of metal oxide particles to which an organic compound containing a polymerizable unsaturated group is bonded; and

(B) 20 to 50 wt% of a compound shown by the following formula (1), the amount of each component being based on the total amount of the composition excluding a solvent,

wherein R¹, R², and R³ individually represent monovalent organic groups, with at least two of R¹, R², and R³ being -R⁴OCOCR⁵=CH₂, R⁴ represents a divalent organic group having 2 to 8 carbon atoms, and R⁵ represents a hydrogen atom or a methyl group.

2. The curable composition according to claim 1, wherein the component (B) is tris((meth)acryloxyethyl) isocyanurate.

3. The curable composition according to claim 1 or 2, wherein the organic compound in the particles of the component (A) includes a group of the following formula (2) in addition to the polymerizable unsaturated group,

— U-C-N- (2)

Il V

4. The curable composition according to claim 3, wherein the organic compound in the particles of the component (A) is a compound having a silanol group or a compound which forms a silanol group by hydrolysis in the molecule.

5. The curable composition according to any of claims 1 to 4, further comprising: (C) 5 to 20 wt% of a urethane (meth)acrylate based on the total amount of the composition excluding a solvent.

6. The curable composition according to any of claims 1 to 5, further comprising: (D) 5 to 20 wt% of a polyfunctional (meth)acrylate compound other than the components (A), (B) and (C) based on the total amount of the composition excluding a solvent.

7. The curable composition according to claim 6, wherein the component (D) contains dipentaerythritol hexaacrylate.

8. The curable composition according to any of claims 1 to 7, comprising the component (B) in an amount of 40 wt% or more of 100 wt% of the total (meth)acrylate component in the composition excluding the component (A) (total amount of components (B), (C), and (D)).

9. A cured film produced by curing the curable composition according to any of claims 1 to 8.

10. A laminate, comprising the cured film according to claim 9.