TWI837373B - Inorganic fine particle dispersions, curable compositions, cured products and optical components - Google Patents

Abstract

The present invention provides an inorganic microparticle dispersion, a curable composition and an optical component, wherein the inorganic microparticle dispersion is an inorganic microparticle dispersion containing inorganic microparticles (A) and a dispersant (B), and is characterized in that the dispersant (B) contains a phosphate compound (b1) having at least one (meth)acrylic group and at least one polyester chain, and a hydroxyl-containing compound (b2) having a molecular weight of 250 or less. The inorganic microparticle dispersion has excellent dispersion stability and can form a cured coating having high refractive index performance and excellent anti-bleeding properties.

Description

Inorganic microparticle dispersion, curable composition, cured product and optical component

The present invention relates to an inorganic microparticle dispersion, a curable composition containing the same, a cured product, and an optical component.

In recent years, with the rapid development of display technology such as liquid crystal display devices, the demand for sheet or film optical components with new functions or higher quality optical components used therein has also been increasing. As such optical components, for example, brightening sheets such as prism sheets or microlens sheets used for the backlight of liquid crystal display devices can be listed. These brightening sheets are usually laminated on a substrate with an optical functional layer having a fine concave-convex structure on the surface. The fine concave-convex structure on the surface refracts the backlight, thereby increasing the brightness of the front of the display. The brightening sheet is mainly manufactured by using a mold to shape a resin material, so the resin material is required to be solvent-free and have a low viscosity.

In addition, in order to improve the brightening effect, the obtained hardened material is also required to have a high refractive index performance and not bleed out under high temperature and high humidity.

As a previously known resin material for a brightening sheet, there is a known resin composition containing metal oxide nanoparticles, and the characteristics are: the metal oxide nanoparticles have a distribution in which the cumulative 10% particle size is 5nm~25nm, the cumulative 50% particle size is 7nm~30nm, the cumulative 90% particle size is 15nm~50nm, and the cumulative 100% particle size is 50nm~250nm, and the resin component contains a compound having two or more benzene skeletons (for example, refer to Patent Document 1). This inorganic microparticle-blended resin material has high refractive index performance, but on the other hand, there is a problem that it tends to have high viscosity due to the formulation of inorganic microparticles.

Therefore, a material with low viscosity is sought despite containing inorganic microparticles.

[Prior art literature] [Patent Literature]

[Patent document 1] Japanese Patent Publication No. 2013-249439

The problem to be solved by the present invention is to provide an inorganic microparticle dispersion with excellent dispersion stability, a curable composition containing the inorganic microparticle dispersion with low viscosity and capable of forming a cured coating with high refractive index performance and excellent anti-leakage properties, a cured product, and an optical component. Furthermore, the so-called "leakage" in the present invention refers to the phenomenon that the uncured components of the curable composition leak out over time under high temperature and high humidity.

The inventors of the present invention have conducted diligent research to solve the above-mentioned problem, and found that the above-mentioned problem can be solved by using an inorganic microparticle dispersion containing inorganic microparticles and a dispersant having a specific structure, thereby completing the present invention.

That is, the present invention relates to an inorganic microparticle dispersion, a curable composition containing the same, a cured product, and an optical component, wherein the inorganic microparticle dispersion is an inorganic microparticle dispersion containing inorganic microparticles (A) and a dispersant (B), wherein the dispersant (B) contains a phosphate compound (b1) having at least one (meth)acrylic group and at least one polyester chain, and a hydroxyl-containing compound (b2) having a molecular weight of 250 or less.

The inorganic microparticle dispersion of the present invention has excellent dispersion stability, and the curable composition containing it has low viscosity and can form a cured coating with high refractive index performance and excellent anti-leaking properties. Therefore, it can be preferably used in optical components such as prisms, microlenses, and other brightening sheets.

The inorganic microparticle dispersion of the present invention is characterized by containing inorganic microparticles (A) and a dispersant (B).

As the inorganic microparticles (A), for example, zirconia, silicon dioxide, barium sulfate, zinc oxide, barium titanate, niobium oxide, aluminum oxide, titanium oxide, niobium oxide, tin oxide, tungsten oxide, antimony oxide, etc. can be listed. These inorganic microparticles can be used alone or in combination of two or more. In addition, among these, zirconia is preferred in terms of the high refractive index performance of the obtained hardened coating.

When zirconia is used as the inorganic microparticle (A), the zirconia may be a generally known one, and the shape of the particles is not particularly limited. For example, spherical, hollow, porous, rod-shaped, fibrous, etc. can be listed, and spherical is preferred. In addition, the average primary particle size is preferably 1nm~50nm, and more preferably 1nm~30nm. Furthermore, the crystal structure is also not particularly limited, but preferably a monoclinic system.

Furthermore, the average primary particle size of the present invention can be measured by directly measuring the size of the primary particles based on electron microscope photos using a transmission electron microscopy (TEM). As a measurement method, for example, the short axis diameter and long axis diameter of the primary particles of each inorganic microparticle are measured and the average value is used as the average primary particle size of the primary particles.

As the dispersant (B), a phosphate compound (b1) having at least one (meth)acryl group and at least one polyester chain, and a hydroxyl-containing compound (b2) having a molecular weight of 250 or less must be used.

Furthermore, in the present invention, the so-called "(meth)acryl" refers to acryl and/or methacryl. In addition, the so-called "(meth)acrylate" refers to acrylate and/or methacrylate. Furthermore, the so-called "(meth)acrylic acid" refers to acrylic acid and/or methacrylic acid.

The phosphate compound (b1) is not particularly limited as long as it has at least one (meth)acrylic group and at least one polyester chain. The inorganic microparticle dispersion obtained has excellent dispersion stability, and the curable composition containing it has low viscosity and can form a cured coating with high refractive index performance and excellent anti-bleeding properties. The preferred one is represented by the following structural formula (1).

[Chemistry 2]

(In the formula, ^R1 is a hydrogen atom or a methyl group, ^R2 is an alkylene chain having 2 to 4 carbon atoms. In addition, x is an integer of 4 to 10, y is an integer greater than or equal to 1, and n is an integer of 1 to 3.)

Regarding the phosphate compound represented by the structural formula (1), the obtained inorganic microparticle dispersion has excellent dispersion stability, and the curable composition containing it has low viscosity and can form a cured coating with high refractive index performance and excellent anti-bleeding properties. In the formula, x is preferably 4 or 5, and y is preferably an integer of 2 to 7. In addition, the dispersant represented by the structural formula (1) may also be a mixture in which n is 1, 2 and/or 3.

As the hydroxyl group-containing compound (b2), one having a molecular weight of 250 or less is used.

Examples of the hydroxyl-containing compound (b2) include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, heptanol, hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecyl alcohol, allyl alcohol, cyclohexanol, terpineol, dihydropinoresinol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, etc.

In addition, as the hydroxyl-containing compound (b2), the following may be used: hydroxyl ethyl (meth)acrylate, hydroxyl propyl (meth)acrylate, trihydroxymethylpropane (meth)acrylate, pentaerythritol acrylate and other hydroxyl-containing (meth)acrylate compounds; (poly)oxyalkylene modified products in which (poly)oxyethylene chains, (poly)oxypropylene chains, (poly)oxytetramethylene chains and other (poly)oxyalkylene chains are introduced into the molecular structure of the hydroxyl-containing (meth)acrylate compounds; lactone modified products in which (poly)lactone structures are introduced into the molecular structure of the hydroxyl-containing (meth)acrylate compounds, etc.

Among these, the obtained inorganic microparticle dispersion has excellent dispersion stability, and the curable composition containing it has low viscosity and can form a cured coating with high refractive index performance and excellent anti-bleeding properties. The lactone modified body introduced into the molecular structure of the hydroxyl-containing (meth)acrylate compound is preferred. In addition, these hydroxyl-containing compounds (b2) can be used alone or in combination of two or more.

Regarding the usage amount of the hydroxyl group-containing compound (b2), the usage amount is preferably in the range of 0.05 to 30 parts by mass, and more preferably in the range of 0.1 to 20 parts by mass, relative to 100 parts by mass of the phosphate compound (b1), so that the obtained inorganic microparticle dispersion has excellent dispersion stability, and the curable composition containing the same has low viscosity and can form a cured coating having high refractive index performance and excellent anti-bleeding properties.

As the dispersant (B), other dispersants may be used in combination as needed.

Examples of the other dispersants include anionic dispersants having acid groups such as carboxylic acid, sulfuric acid, sulfonic acid, and salts of these acid compounds. These other dispersants may be used alone or in combination of two or more.

Regarding the usage amount of the dispersant (B), the usage amount is preferably in the range of 5 to 40 parts by mass, and more preferably in the range of 10 to 25 parts by mass, relative to 100 parts by mass of the inorganic fine particles (A), so that the obtained inorganic fine particle dispersion has excellent dispersion stability, and the curable composition containing the inorganic fine particles has low viscosity and can form a cured coating having high refractive index performance and excellent anti-bleeding properties.

The inorganic microparticle dispersion of the present invention may also contain a silane coupling agent as needed.

Examples of the silane coupling agent include (meth)acryloxy silane coupling agents such as 3-(meth)acryloxypropyltrimethylsilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, and 3-(meth)acryloxypropyltriethoxysilane; and (meth)acryloxy silane coupling agents such as allyltrichlorosilane, allyltriethoxysilane, allyltrimethoxysilane, and diethoxysilane. Vinyl silane coupling agents such as methylvinylsilane, trichlorovinylsilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(2-methoxyethoxy)silane, etc.; cyclohexane such as diethoxy(glycidyloxypropyl)methylsilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-glycidyloxypropyltriethoxysilane, etc. Oxygen-based silane coupling agents; styrene-based silane coupling agents such as p-phenylene trimethoxysilane; N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylene)propylamine, N-phenyl-3-amino Amine-based silane coupling agents such as propyltrimethoxysilane; urea-based silane coupling agents such as 3-ureidopropyltriethoxysilane; chloropropyl-based silane coupling agents such as 3-chloropropyltrimethoxysilane; alkyl-based silane coupling agents such as 3-alkylpropylmethyldimethoxysilane and 3-alkylpropyltrimethoxysilane; sulfide-based silane coupling agents such as bis(triethoxysilylpropyl)tetrasulfide; isocyanate-based silane coupling agents such as 3-isocyanatepropyltriethoxysilane; aluminum-based coupling agents such as acetoxydiisopropionate, etc. These silane coupling agents may be used alone or in combination of two or more. Among these, 3-(meth)acryloxypropyltrimethoxysilane is preferred in terms of good compatibility with the (meth)acryl group-containing compound (C) described later.

Regarding the amount of the silane coupling agent used, the amount is preferably in the range of 10 to 30 parts by mass relative to 100 parts by mass of the inorganic microparticles (A), so that the obtained inorganic microparticle dispersion has excellent dispersion stability, and the curable composition containing the inorganic microparticle has low viscosity and can form a cured coating having high refractive index performance and excellent anti-leaking properties.

As a method for producing the inorganic microparticle dispersion of the present invention, the inorganic microparticle (A) can be dispersed using the dispersant (B). For example, the following method can be cited: the inorganic microparticle (A) and the dispersant (B) are put into a stirrer and stirred for 0.5 hours to 2 hours, and then dispersed using a disperser until the particle size of the inorganic microparticle (A) becomes less than 60nm to obtain the inorganic microparticle dispersion.

As the above-mentioned disperser, for example, a medium-type wet disperser can be cited, and as the above-mentioned medium-type wet disperser, for example, a bead mill can be cited.

The medium used in the medium-type wet disperser is not particularly limited as long as it is a commonly known bead, and examples thereof include zirconia, aluminum oxide, silicon dioxide, glass, silicon carbide, silicon nitride, etc. The average particle size of the medium is preferably in the range of 50μm to 500μm, and more preferably in the range of 100μm to 200μm. If the particle size is 50μm or more, the impact force on the raw material powder is appropriate, and no excessive time is required for dispersion. On the other hand, if the particle size of the medium is 500μm or less, the impact force on the raw material powder is appropriate, so the surface energy of the dispersed particles can be suppressed from increasing, thereby preventing re-agglomeration.

In addition, the dispersion step time can be shortened by using a two-stage method of using a large-particle medium with a strong impact force in the initial stage of dispersion and using a small-particle medium that is less likely to re-agglomerate after the dispersed particles have become smaller in size.

In addition, the curable composition of the present invention contains the inorganic microparticle dispersion and a (meth)acryl-containing compound (C).

Examples of the (meth)acryl group-containing compound (C) include monofunctional or polyfunctional (meth)acrylate compounds, epoxy (meth)acrylate compounds, urethane (meth)acrylate compounds, etc. In addition, the same (meth)acryl group-containing compound as the dispersant (B) can also be used.

Examples of the monofunctional or polyfunctional (meth)acrylate compounds include: aliphatic mono(meth)acrylate compounds such as methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, butyl(meth)acrylate, pentyl(meth)acrylate, hexyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, and octyl(meth)acrylate; alicyclic mono(meth)acrylate compounds such as cyclohexyl(meth)acrylate, isobornyl(meth)acrylate, and adamantyl mono(meth)acrylate; heterocyclic mono(meth)acrylate compounds such as glycidyl(meth)acrylate and tetrahydrofurfuryl acrylate; Aromatic mono(meth)acrylate compounds such as benzyl(meth)acrylate, phenyl(meth)acrylate, phenoxy(meth)acrylate, phenoxyethyl(meth)acrylate, phenoxyethoxyethyl(meth)acrylate, 2-hydroxy-3-phenoxypropyl(meth)acrylate, phenoxybenzyl(meth)acrylate, benzylbenzyl(meth)acrylate, phenylphenoxyethyl(meth)acrylate; hydroxyl-containing mono(meth)acrylate compounds such as hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, hydroxybutyl(meth)acrylate; mono(meth)acrylate compounds such as the compound represented by the following structural formula (2); [Chemical 3]

The present invention relates to a polyoxyalkylene-modified mono(meth)acrylate compound in which a polyoxyalkylene chain such as a polyoxyethylene chain, a polyoxypropylene chain, or a polyoxytetramethylene chain is introduced into the molecular structure of the various mono(meth)acrylate compounds; a lactone-modified mono(meth)acrylate compound in which a structure derived from (poly)lactone is introduced into the molecular structure of the various mono(meth)acrylate compounds; an aliphatic di(meth)acrylate compound such as ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate; 1,4-cyclohexanedimethanol di(meth)acrylate, norbornane di(meth)acrylate, norbornane dimethanol di(meth)acrylate, and the like. alicyclic di(meth)acrylate compounds such as acrylate, dicyclopentyl di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate; aromatic di(meth)acrylate compounds such as biphenol di(meth)acrylate, bisphenol di(meth)acrylate; hydroxyl-containing di(meth)acrylate compounds such as glycerol di(meth)acrylate, trihydroxymethylpropane di(meth)acrylate; polyoxyalkylene-modified di(meth)acrylate compounds in which polyoxyalkylene chains such as polyoxyethylene chains, polyoxypropylene chains, and polyoxytetramethylene chains are introduced into the molecular structures of the above-mentioned various di(meth)acrylate compounds; lactone-modified di(meth)acrylate compounds in which (poly)lactone structures are introduced into the molecular structures of the above-mentioned various di(meth)acrylate compounds; compounds; aliphatic tri(meth)acrylate compounds such as trihydroxymethylpropane tri(meth)acrylate and glycerol tri(meth)acrylate; hydroxyl-containing tri(meth)acrylate compounds such as pentaerythritol tri(meth)acrylate, di-trihydroxymethylpropane tri(meth)acrylate and dipentaerythritol tri(meth)acrylate; polyoxyalkylene-modified tri(meth)acrylate compounds in which polyoxyalkylene chains such as polyoxyethylene chains, polyoxypropylene chains and polyoxytetramethylene chains are introduced into the molecular structures of the various tri(meth)acrylate compounds; lactone-modified tri(meth)acrylate compounds in which (poly)lactone structures are introduced into the molecular structures of the various tri(meth)acrylate compounds; pentaerythritol tetra(meth)acrylate, di-trihydroxymethylpropane tri(meth)acrylate and dipentaerythritol tri(meth)acrylate; aliphatic poly(meth)acrylate compounds having four or more functions, such as alkane tetra(meth)acrylate and dipentaerythritol hexa(meth)acrylate; poly(meth)acrylate compounds having four or more functions, such as dipentaerythritol tetra(meth)acrylate and dipentaerythritol penta(meth)acrylate, hydroxyl-containing poly(meth)acrylate compounds having four or more functions, such as polyoxyethylene chains, polyoxypropylene chains and polyoxytetramethylene chains, introduced into the molecular structure of the above-mentioned various poly(meth)acrylate compounds; lactone-modified poly(meth)acrylate compounds having four or more functions, such as poly(meth)lactone structures, introduced into the molecular structure of the above-mentioned various poly(meth)acrylate compounds; bicarbazole compounds represented by the following structural formula (3), etc.

[Chemistry 4]

(Wherein, ^X1 and ^X2 are independently a hydrogen atom or a (meth)acryloyl group.)

The epoxy (meth)acrylate compound is obtained by reacting (meth)acrylic acid or its anhydride with an epoxy resin. Examples of the epoxy resin include: diglycidyl ethers of dihydric phenols such as hydroquinone and o-catechol; diglycidyl ethers of biphenol compounds such as 3,3'-biphenyldiol and 4,4'-biphenyldiol; bisphenol A type epoxy Bisphenol-type epoxy resins such as bisphenol B epoxy resins, bisphenol F epoxy resins, and bisphenol S epoxy resins; polyglycidyl ethers of naphthol compounds such as 1,4-naphthalenediol, 1,5-naphthalenediol, 1,6-naphthalenediol, 2,6-naphthalenediol, 2,7-naphthalenediol, binaphthol, and bis(2,7-dihydroxynaphthyl)methane; 4,4 ',4"-methylenetriphenol and other triglycidyl ethers; phenol novolac epoxy resins, cresol novolac epoxy resins and other novolac epoxy resins; polyglycidyl ethers of polyether-modified aromatic polyols obtained by ring-opening polymerization of the biphenol compound, bisphenol compound, or naphthol compound with ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether and other cyclic ether compounds; polyglycidyl ethers of lactone-modified aromatic polyols obtained by condensation of the biphenol compound, bisphenol compound, or naphthol compound with lactone compounds such as ε-caprolactone, etc.

These epoxy (meth)acrylate compounds may be used alone or in combination of two or more.

Examples of the urethane (meth)acrylate include those obtained by reacting a polyisocyanate compound, a hydroxyl group-containing (meth)acrylate compound, and an optional polyol compound. Examples of the polyisocyanate compound include diisocyanate compounds such as hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, xylene diisocyanate, and 4,4'-diphenylmethane diisocyanate, and urate modified products, adduct modified products, and biuret modified products thereof. Examples of the hydroxyl-containing (meth)acrylate compound include: hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, trihydroxymethylpropane diacrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and polyoxyalkylene modified products and polylactone modified products thereof. Examples of the polyol compound include: ethylene glycol, propylene glycol, butanediol, hexanediol, polyoxyethylene glycol, polyoxypropylene glycol, glycerol, trihydroxymethylpropane, pentaerythritol, biphenol, bisphenol, etc.

These (meth)acryloyl-containing compounds (C) can be used alone or in combination of two or more. Among these, compounds having an aromatic ring in the molecular structure are preferred, and compounds having a bisphenol structure in the molecular structure are more preferred, since the obtained inorganic microparticle dispersion has excellent dispersion stability, and the curable composition containing the inorganic microparticle dispersion has low viscosity and can form a cured coating having high refractive index performance and excellent anti-bleeding properties.

Regarding the usage amount of the (meth)acryl group-containing compound (C), the usage amount is preferably 10 parts by mass or more, and more preferably 40 parts by mass or more, relative to 100 parts by mass of the inorganic microparticle dispersion, so that the obtained curable composition has a low viscosity and can form a cured coating having a high refractive index performance and excellent anti-bleeding properties.

The curable composition of the present invention may also contain a photopolymerization initiator.

Examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propane-1-one, thioxanthrone and thioxanthrone derivatives, 2,2'-dimethoxy-1,2-diphenylethane-1-one, dimethoxy-1,2-diphenylethane-1-one, and dimethoxy-1,2-diphenylethane-1-one. Phenyl (2,4,6-trimethoxybenzyl) phosphine oxide, 2,4,6-trimethylbenzyl diphenyl phosphine oxide, bis (2,4,6-trimethylbenzyl) phenyl phosphine oxide, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, etc.

Examples of commercially available other photopolymerization initiators include: Omnirad-1173, Omnirad-184, Omnirad-127, Omnirad-2959, Omnirad-369, Omnirad-379, Omnirad-907, Omnirad-4265, Omnirad-1000, Omnirad-651, Omnirad-TPO, Omnirad-81 ... )-2022", "Omnirad-2100", "Omnirad-754", "Omnirad-784", "Omnirad-500", "Omnirad-81" (manufactured by IGM); "Kayacure-DETX", "Kayacure-MBP", "Kayacure-DMBI", "Kayacure-EPA", "Kayacure-OA" (manufactured by Nippon Kayaku Co., Ltd.); "Vicure-10", "Vicure-55" (manufactured by Stauffer Chemical Co., Ltd. "Trigonal P1" (manufactured by Akzo Chemical); "Sandoray 1000" (manufactured by SANDOZ); "Deap" (manufactured by APJOHN); "Quantacure-PDO", "Quantacure-ITX", "Quantacure-EPD" (manufactured by Ward Blenkinsop); "Runtecure-1104" (manufactured by Runtec), etc. These photopolymerization initiators can be used alone or in combination of two or more.

In the curable composition, the amount of the photopolymerization initiator added is preferably in the range of 0.05 mass% to 20 mass%, and more preferably in the range of 0.1 mass% to 10 mass%.

In addition, photosensitizers may be added to improve curability.

As the photosensitizer, for example, there can be listed: amine compounds such as aliphatic amines and aromatic amines; urea compounds such as o-tolylthiourea; sulfur compounds such as sodium diethyldithiophosphate and s-benzylisothiouronium-p-toluenesulfonate. These photosensitizers can be used alone or in combination of two or more. In addition, the amount of these photosensitizers added to the curable composition is preferably in the range of 0.01 mass% to 10 mass%.

The curable composition of the present invention may also contain other additives as needed. As the other additives, for example, there can be listed: ultraviolet absorbers, antioxidants, silicone additives, fluorine additives, rheology control agents, defoaming agents, antistatic agents, antifogging agents, etc. In the curable composition of the present invention, the addition amount of these other additives is preferably in the range of 0.01 mass% to 40 mass%.

The method for producing the curable composition of the present invention is not particularly limited, and examples thereof include: a method of dispersing raw materials including the inorganic microparticles (A), the dispersant (B), and the (meth)acryloyl-containing compound (C) or other additives.

The disperser used in the method can be any commonly known disperser such as a medium-type wet disperser without limitation, for example, a bead mill ("Star Mill LMZ-015" manufactured by Ashizawa Finetech Co., Ltd., "Ultra Apex Mill UAM-015" manufactured by Shou Industry Co., Ltd., etc.).

The medium used in the disperser is not particularly limited as long as it is a commonly known bead. Preferably, zirconia, alumina, silicon dioxide, glass, silicon carbide, and silicon nitride can be listed. The average particle size of the medium is preferably 50μm~500μm, and more preferably 100μm~200μm. If the particle size is 50μm or more, the impact force on the raw material powder is appropriate, and it does not take too much time to disperse. On the other hand, if the particle size of the medium is 500μm or less, the impact force on the raw material powder is appropriate, so the surface energy of the dispersed particles can be suppressed, thereby preventing re-agglomeration.

In addition, the dispersion step time can be shortened by a two-stage method of using a large-particle medium with a strong impact force in the initial stage of dispersion and using a small-particle medium that is less likely to re-agglomerate after the particle size of the dispersed particles becomes smaller.

As methods for curing the curable composition of the present invention, for example, there can be cited a method of heating and a method of irradiating active energy rays such as ultraviolet rays.

As the heating method, hardening can be performed by heating in a temperature range of 60°C to 120°C for 5 minutes to 60 minutes.

In addition, as the method of irradiating active energy rays, for example, in the case of ultraviolet rays, curing can be performed by using ultraviolet lamps such as low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, gallium lamps, metal halide lamps, sunlight, and light emitting diodes (LEDs) as ultraviolet light generation sources.

As the active energy rays, in addition to the ultraviolet rays, ionizing radiation such as electron beams, α rays, β rays, and γ rays may also be used.

The irradiation amount of the active energy ray is preferably in the range of 0.05 J/cm ² to 5 J/cm ² , more preferably in the range of 0.1 J/cm ² to 3 J/cm ² , and particularly preferably in the range of 0.1 J/cm ² to 1 J/cm ^2. In addition, the irradiation amount of the ultraviolet ray is based on the value measured using an ultraviolet checker (UV Checker) UVR-N1 (manufactured by Nippon Denko Co., Ltd.) in the wavelength range of 300 nm to 390 nm.

The hardened coating of the hardening composition of the present invention has high refractive index performance and can be preferably used in optical components.

As the optical components, for example, there can be listed: plastic lenses, polarizing films, phase difference films, anti-reflection films, brightness enhancement films (prisms, micro lenses, etc.), light diffusion films, hard coating films, film-type liquid crystal elements, touch panels, etc.

[Implementation example]

The present invention is described in detail below through embodiments and comparative examples.

(Example 1: Preparation of Inorganic Microparticle Dispersion (1))

166.5 parts by weight of zirconia nanoparticle powder (UEP-100 manufactured by Daiichi Rare Earth Chemical Co., Ltd., primary particle size 11 nm), 33.0 parts by weight of 3-(meth)acryloyloxypropyltrimethoxysilane (KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.), and a dispersant (B-1) [ ^R1 in the structural formula (1) is methyl, R A mixture obtained by mixing a phosphate compound (b1-1) in which ^x is an ethyl chain having 2 carbon atoms, x is 5, y is 2 (average value), and n is an integer of 1 to 3 and a 1 mol caprolactone adduct of hydroxyethyl methacrylate (b2-1) (Placcel FM1 manufactured by Daicel Co., Ltd., molecular weight: 244) in a ratio of (b1-1)/(b2-1) of 100/0.5] and 42.0 parts by mass of methyl ethyl ketone (hereinafter referred to as "MEK (methyl ethyl ketone)") were mixed and stirred for 30 minutes with a dispersing stirrer to perform coarse dispersion. Next, the obtained mixed solution was dispersed using a medium-type wet disperser ("Star Mill LMZ-015" manufactured by Ashizawa Finetech Co., Ltd.) using zirconia beads with a particle size of 100 μm. The dispersion treatment was performed for a retention time of 100 minutes while checking the particle size during the process, and an inorganic fine particle dispersion (1) was obtained.

(Example 2: Preparation of Inorganic Microparticle Dispersion (2))

An inorganic fine particle dispersion (2) was obtained in the same manner as in Example 1 except that the dispersant (B-2) [a mixture of a phosphate compound (b1-1) in which ^R1 in the structural formula (1) is a methyl group, ^R2 is an ethyl chain having 2 carbon atoms, x is 5, y is 2 (average value), and n is an integer of 1 to 3, and hydroxyethyl methacrylate (b2-2) (molecular weight: 130) in a ratio of (b1-1)/(b2-2) of 100/1.6] was used instead of the dispersant (B-1) used in Example 1.

(Example 3: Preparation of Inorganic Microparticle Dispersion (3))

An inorganic fine particle dispersion (3) was obtained in the same manner as in Example 1 except that the dispersant (B-3) [a mixture of a phosphate compound (b1-1) in which ^R1 in the structural formula (1) is a methyl group, ^R2 is an ethyl chain having 2 carbon atoms, x is 5, y is 2 (average value), and n is an integer of 1 to 3 and a caprolactone 1 mol adduct of hydroxyethyl methacrylate (b2-1) ("Placcel FM1" manufactured by Daicel Co., Ltd., molecular weight: 244) in a ratio of (b1-1)/(b2-1) of 100/18] was used instead of the dispersant (B-1) used in Example 1.

(Example 4: Preparation of Inorganic Microparticle Dispersion (4))

An inorganic fine particle dispersion (4) was obtained in the same manner as in Example 1 except that the dispersant (B-4) [a mixture of a phosphate compound (b1-1) in which ^R1 in the structural formula (1) is a methyl group, ^R2 is an ethyl chain having 2 carbon atoms, x is 5, y is 2 (average value), and n is an integer of 1 to 3 and a caprolactone 1 mol adduct of hydroxyethyl methacrylate (b2-1) ("Placcel FM1" manufactured by Daicel Co., Ltd., molecular weight: 244) in a ratio of (b1-1)/(b2-1) of 100/27] was used instead of the dispersant (B-1) used in Example 1.

(Example 5: Preparation of Inorganic Microparticle Dispersion (5))

An inorganic fine particle dispersion (5) was obtained in the same manner as in Example 1 except that the dispersant (B-5) [a mixture of a phosphate compound (b1-1) in which ^R1 in the structural formula (1) is a methyl group, ^R2 is an ethyl chain having 2 carbon atoms, x is 5, y is 2 (average value), and n is an integer of 1 to 3 and a 1 mol caprolactone adduct of hydroxyethyl methacrylate (b2-1) ("Placcel FM1" manufactured by Daicel Co., Ltd., molecular weight: 244) in a ratio of (b1-1)/(b2-1) of 100/2] was used instead of the dispersant (B-1) used in Example 1.

(Example 6: Preparation of Inorganic Microparticle Dispersion (6))

The same procedures as in Example 1 were followed except that dispersant (B-6) [a mixture of a phosphate compound (b1-2) in which ^R1 in the structural formula (1) is a methyl group, ^R2 is an ethyl chain having 2 carbon atoms, x is 5, y is 3 (average value), and n is an integer of 1 to 3 and a caprolactone 1 mol adduct of hydroxyethyl methacrylate (b2-1) (Placcel FM1 manufactured by Daicel Co., Ltd., molecular weight: 244) in a ratio of (b1-2)/(b2-1) of 100/0.5] was used instead of dispersant (B-1) used in Example 1, thereby obtaining an inorganic fine particle dispersion (6).

(Example 7: Preparation of Inorganic Microparticle Dispersion (7))

The same procedures as in Example 1 were followed except that dispersant (B-7) [a mixture of a phosphate compound (b1-3) in which ^R1 in the structural formula (1) is a methyl group, ^R2 is an ethyl chain having 2 carbon atoms, x is 5, y is 5 (average value), and n is an integer of 1 to 3 and a caprolactone 1 mol adduct of hydroxyethyl methacrylate (b2-1) (Placcel FM1 manufactured by Daicel Co., Ltd., molecular weight: 244) in a ratio of (b1-3)/(b2-1) of 100/0.5] was used instead of dispersant (B-1) used in Example 1, thereby obtaining an inorganic fine particle dispersion (7).

(Example 8: Preparation of Inorganic Microparticle Dispersion (8))

An inorganic fine particle dispersion (8) was obtained in the same manner as in Example 1 except that the dispersant (B-8) [a mixture of a phosphate compound (b1-1) in which ^R1 in the structural formula (1) is a methyl group, ^R2 is an ethyl chain having 2 carbon atoms, x is 5, y is 2 (average value), and n is an integer of 1 to 3 and a caprolactone 1 mol adduct of hydroxyethyl methacrylate (b2-1) ("Placcel FM1" manufactured by Daicel Co., Ltd., molecular weight: 244) in a ratio of (b1-1)/(b2-1) of 100/35] was used instead of the dispersant (B-1) used in Example 1.

(Example 9: Preparation of Inorganic Microparticle Dispersion (9))

An inorganic fine particle dispersion (9) was obtained in the same manner as in Example 1 except that dispersant (B-9) [a mixture of a phosphate compound (b1-1) in which ^R1 in the structural formula (1) is a methyl group, ^R2 is an ethyl chain having 2 carbon atoms, x is 5, y is 2 (average value), and n is an integer of 1 to 3, and 1-butanol (b2-3) (molecular weight: 74) in a ratio of (b1-1)/(b2-3) of 100/0.5] was used instead of dispersant (B-1) used in Example 1.

(Example 10: Preparation of Inorganic Microparticle Dispersion (10))

An inorganic microparticle dispersion (10) was obtained in the same manner as in Example 1 except that the dispersant (B-10) [a mixture of a phosphate compound (b1-1) in which ^R1 in the structural formula (1) is a methyl group, ^R2 is an ethyl chain having 2 carbon atoms, x is 5, y is 2 (average value), and n is an integer of 1 to 3, and ethylene glycol (b2-4) (molecular weight: 62) in a ratio of (b1-1)/(b2-4) of 100/0.5] was used instead of the dispersant (B-1) used in Example 1.

(Comparative Example 1: Production of Inorganic Microparticle Dispersion (11))

An inorganic fine particle dispersion (11) was obtained in the same manner as in Example 1, except that the dispersant (B-11) [a phosphate compound (b1-1) in which ^R1 in the structural formula (1) is a methyl group, ^R2 is an ethyl chain having 2 carbon atoms, x is 5, y is 2 (average value), and n is an integer of 1 to 3] was used instead of the dispersant (B-1) used in Example 1.

(Comparative Example 2: Production of Inorganic Microparticle Dispersion (12))

An inorganic microparticle dispersion (12) was obtained in the same manner as in Example 1, except that the dispersant (B-12) [a phosphate compound (b1-4) in which ^R1 in the structural formula (1) is a methyl group, ^R2 is an ethyl chain having 2 carbon atoms, x is 5, y is 1 (average value), and n is an integer of 1 to 3] was used instead of the dispersant (B-1) used in Example 1.

(Comparative Example 3: Production of Inorganic Microparticle Dispersion (13))

Inorganic fine particle dispersion (13) was obtained in the same manner as in Example 1 except that the dispersant (B-13) represented by the following structural formula (4) was used instead of the dispersant (B-1) used in Example 1.

[Chemistry 5]

(The n in the formula is an integer between 1 and 3.)

(Comparative Example 4: Production of Inorganic Microparticle Dispersion (14))

Inorganic fine particle dispersion (14) was obtained in the same manner as in Example 1 except that the dispersant (B-14) represented by the following structural formula (5) was used instead of the dispersant (B-1) used in Example 1.

(The n in the formula is an integer between 1 and 3.)

(Comparative Example 5: Production of Inorganic Microparticle Dispersion (15))

Inorganic fine particle dispersion (15) was obtained in the same manner as in Example 1 except that the dispersant (B-15) represented by the following structural formula (6) was used instead of the dispersant (B-1) used in Example 1.

[Chemistry 7]

(The n in the formula is an integer between 1 and 3.)

(Comparative Example 6: Production of Inorganic Microparticle Dispersion (16))

An inorganic microparticle dispersion (16) was obtained in the same manner as in Example 1 except that the dispersant (B-1) used in Example 1 was replaced with the dispersant (B-16) [a mixture of a phosphate compound (b1-1) in which ^R1 in the structural formula (1) is a methyl group, ^R2 is an ethyl chain having 2 carbon atoms, x is 5, y is 2 (average value), and n is an integer of 1 to 3 and 1-octadecanol (b2-5) (molecular weight: 270) in a ratio of (b1-1)/(b2-5) of 100/2].

(Example 11: Preparation of curable composition (1))

Phenyl benzyl acrylate was added to the inorganic microparticle dispersion (1) obtained in Example 1 in the proportion shown in Table 1, and the volatile components were removed by decompression while heating using an evaporator. Furthermore, a photopolymerization initiator was added to obtain a curable composition (1).

(Example 12 to Example 22: Preparation of hardening composition (2) to hardening composition (12))

The hardening composition (2) to the hardening composition (12) were obtained by the same method as in Example 11 using the composition and blending ratio shown in Table 1.

(Comparative Example 7~Comparative Example 12: Preparation of hardening composition (C1)~hardening composition (C6))

The hardening composition (C1) to the hardening composition (C6) were obtained by the same method as in Example 11 using the composition and blending ratio shown in Table 2.

The inorganic microparticle dispersion and curable composition obtained in the above-mentioned examples and comparative examples were used to perform the following measurements and evaluations.

[Method for measuring refractive index]

The curable composition obtained in the embodiment and the comparative example was applied to a glass plate using an applicator so that the film thickness during curing was 50 μm, and active energy rays were irradiated to form a cured coating film of the curable composition on the surface of the glass plate. The cured coating film was peeled off from the glass substrate, and its refractive index was measured using an Abbe refractometer ("NAR-3T" manufactured by Atago Co., Ltd.).

[Evaluation method of viscosity stability]

The viscosity of the curable composition obtained in the examples and comparative examples was measured using an E-type rotational viscometer ("RE80U" manufactured by Toki Sangyo Co., Ltd.) at 25°C just after preparation (hereinafter referred to as "initial viscosity") and at 40°C × one month later (hereinafter referred to as "viscosity after one month"), and evaluated according to the following evaluation criteria.

◎: The value obtained by dividing the viscosity after one month by the initial viscosity is 0% or more and less than 10%.

○: The value obtained by dividing the viscosity after one month by the initial viscosity is 10% or more and less than 15%.

△: The value obtained by dividing the viscosity after one month by the initial viscosity is more than 15% and less than 20%.

×: The value obtained by dividing the viscosity after one month by the initial viscosity is 20% or more.

[Evaluation method of permeation resistance]

The curable composition obtained in the examples and comparative examples was sandwiched between a polyethylene terephthalate film ("A4300" manufactured by Toyobo Co., Ltd., hereinafter referred to as "PET (polyethylene terephthalate) film") and a brightness enhancing film manufactured by 3M (hereinafter referred to as "BEF (brightness enhancing film) film"), and UV irradiated by a high-pressure mercury lamp of 0.2 J/ ^cm2 , and the BEF film was peeled off to prepare a prism sheet with a prism shape transferred on the PET film. Subsequently, the obtained prism sheet was attached to an acrylic plate and placed at a high temperature and high humidity of 65°C and 95% for 72 hours. After 72 hours, the surfaces of the prism and acrylic plate were visually inspected and evaluated according to the following evaluation criteria.

○: No change at all

×: Osmosis was observed on the surface of the prism or acrylic sheet.

[Evaluation method of dispersion stability]

The dispersion stability was evaluated by the compatibility with the monomer containing the structure derived from ethylene oxide. Specifically, 10 parts by mass of bisphenol A ethylene oxide-modified diacrylate ("MIRAMER M2200" manufactured by MIWON) was added to the inorganic fine particle dispersion obtained in the examples and comparative examples relative to 100 parts by mass of the inorganic fine particle dispersion and mixed, and the evaluation was performed by observing the appearance and according to the following evaluation criteria.

○: No turbidity or aggregation of the inorganic fine particle dispersion was observed.

△: Turbidity was observed in the inorganic microparticle dispersion.

×: The inorganic fine particle dispersion is turbid, and aggregation of particles is observed.

The compositions and evaluation results of the curable compositions (1) to (12) prepared in Examples 11 to 22 are shown in Table 1.

The compositions and evaluation results of the hardening compositions (C1) to (C6) prepared in Comparative Examples 7 to 12 are shown in Table 2.

In Table 1 and Table 2, "Acrylate Monomer 1" represents phenyl benzyl acrylate.

In Table 1, "Acrylate Monomer 2" represents m-phenoxybenzyl acrylate ("Light Acrylate POB-A" manufactured by Kyoeisha Chemical Co., Ltd.).

In Table 1, "Acrylate Monomer 3" represents o-phenylphenoxyethyl acrylate ("MIRAMER M1142" manufactured by MIWON Corporation).

In Table 1, "Acrylate Monomer 4" represents fluorene diacrylate ("OGSOL EA-0200" manufactured by Osaka Gas Chemical Co., Ltd.).

Examples 11 to 22 shown in Table 1 are examples of curable compositions using the inorganic microparticle dispersion of the present invention. It can be confirmed that the inorganic microparticle dispersion of the present invention has excellent dispersion stability, and the curable composition containing it has low viscosity and can form a cured coating with high refractive index performance and excellent anti-bleeding properties.

On the other hand, Comparative Example 7 is an example of an inorganic microparticle dispersion that does not have a hydroxyl-containing compound as a dispersant, and a curable composition containing the inorganic microparticle dispersion. It can be confirmed that although the dispersion stability of the inorganic microparticle dispersion is excellent, the viscosity stability of the curable composition containing it is significantly insufficient.

Comparative Example 8 is an example of an inorganic microparticle dispersion that does not have a hydroxyl-containing compound as a dispersant, and a curable composition containing the inorganic microparticle dispersion. It can be confirmed that although the curable composition has excellent viscosity stability and anti-bleeding properties, the dispersion stability of the inorganic microparticle dispersion is insufficient.

Comparative Examples 9 to 11 are examples of inorganic microparticle dispersions using a phosphate compound without a (meth)acrylic group as a dispersant, and curable compositions containing the inorganic microparticle dispersions. It can be confirmed that the dispersion stability of the inorganic microparticle dispersion is significantly insufficient, and the anti-bleeding property of the curable composition containing the inorganic microparticle dispersion is also significantly insufficient.

Comparative Example 12 is an example of an inorganic microparticle dispersion using a hydroxyl-containing compound with a molecular weight exceeding 250 as a dispersant, and a curable composition containing the inorganic microparticle dispersion. It can be confirmed that the dispersion stability of the inorganic microparticle dispersion is insufficient, and the viscosity stability and anti-bleeding property of the curable composition containing the inorganic microparticle dispersion are also insufficient.

Claims (6)

An inorganic microparticle dispersion comprises inorganic microparticles (A) and a dispersant (B), wherein the inorganic microparticle dispersion is characterized in that the dispersant (B) comprises a phosphate compound (b1) having at least one (meth)acrylic group and at least one polyester chain, and a hydroxyl-containing compound (b2) having a molecular weight of 250 or less, and the amount of the dispersant (B) used is in the range of 5 to 40 parts by mass relative to 100 parts by mass of the inorganic microparticles (A). The inorganic fine particle dispersion according to claim 1, wherein the phosphate compound (b1) is represented by the following structural formula (1):

(wherein, ^R1 is a hydrogen atom or a methyl group, ^R2 is an alkylene chain having 2 to 4 carbon atoms; in addition, x is an integer of 4 to 10, y is an integer greater than 1, and n is an integer of 1 to 3). In the inorganic microparticle dispersion as described in claim 1, the amount of the hydroxyl group-containing compound (b2) used is 0.05 to 30 parts by mass relative to 100 parts by mass of the phosphate compound (b1). A curable composition characterized by comprising an inorganic microparticle dispersion as described in any one of claim 1 to claim 3, and a (meth)acryl-containing compound (C). A hardened product, characterized in that it is a hardening reaction product of the hardening composition as described in claim 4. An optical component characterized by having a hardened coating film containing a hardened material as described in claim 5.