JP2018119086A - Inorganic particle dispersion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dispersion having a good thixotropic property while maintaining its flowability and having excellent practical utility.SOLUTION: The dispersion of the present invention comprises inorganic particles and a dispersion medium and has total light transmittance of 50% or more, where a content of the inorganic particles is 60 mass% or more, the viscosity of the dispersion medium at a temperature of 25°C is 6 mPa s or more, and a viscosity change rate represented by the following formula is 2.0 or more: viscosity change rate=(shear viscosity at shear rate of 1 sat a liquid temperature of 25°C)/(shear viscosity at shear rate of 100 sat a liquid temperature of 25°C).SELECTED DRAWING: None

Description

  The present invention relates to a dispersion in which inorganic particles are dispersed in a dispersion medium.

  Inorganic particles have the potential to exhibit various functions in optical materials, electronic component materials, and the like, and are attracting attention in the field of various functional materials. However, the inorganic particles alone are often aggregated due to insufficient dispersibility in an organic medium, causing problems such as a decrease in transparency and a decrease in mechanical strength. Therefore, inorganic particle dispersions in which inorganic particles are dispersed in a dispersion medium have been proposed. Inorganic particle dispersions are used in coating materials, paints, coating films, films, rubbers, adhesives, pressure-sensitive adhesives, etc., and have various functions. Has attracted attention in the field of sexual materials.

  Patent Document 1 describes a photocurable liquid composition containing an ethylenically unsaturated monomer, a photopolymerization initiator, and alumina particles (number average particle size 170 nm) as inorganic fine particles. Patent Document 2 discloses an active energy ray-curable resin composition containing metal oxide nanoparticles, phenoxybenzyl (meth) acrylates, and a bifunctional (meth) acrylate having a (poly) alkylene glycol structure. Have been described.

JP 2006-348214 A Japanese Patent No. 6022094

  However, the composition described in Patent Document 1 has extremely low fluidity when allowed to stand, so that handling properties at the time of mixing with other components and application may not be sufficient. In the composition described, the storage stability of the dispersion and sagging suppression at the time of application may not always be satisfactory, and the practicality may not be sufficient. This invention is made | formed in view of the said situation, and makes it a subject to provide the dispersion | distribution which was excellent in thixotropy while maintaining the fluidity | liquidity and was excellent in practicality.

  As a result of intensive studies to solve the above problems, the present inventors have increased the proportion of inorganic particles under the condition that the transparency of the dispersion can be maintained, and further increased the viscosity of the dispersion medium. As a result, it was found that an inorganic particle dispersion having good thixotropy while maintaining its fluidity and excellent practicality was obtained, and the present invention was completed.

The present invention includes the following inventions.
[1] Inorganic particles and a dispersion medium are included, the total light transmittance is 50% or more, the content of the inorganic particles is 60% by mass or more, and the viscosity of the dispersion medium at a temperature of 25 ° C. is 6 mPa · s or more. And a dispersion having a viscosity change rate represented by the following formula of 2.0 or more.
Viscosity change rate = (shear viscosity at a liquid temperature of 25 ° C. at a shear rate of 1 s ⁻¹ ) / (shear viscosity at a liquid temperature of 25 ° C. at a shear rate of 100 s ⁻¹ )
[2] The dispersion according to [1], wherein the number average primary particle diameter of the inorganic particles is 50 nm or less.
[3] The dispersion according to [1] or [2], wherein the inorganic particles are metal oxide particles.
[4] The dispersion according to any one of [1] to [3], wherein the metal constituting the inorganic particles is at least one selected from Ti, Al, Zr, Zn, Sn, and Ce.
[5] The dispersion according to any one of [1] to [4], further comprising an organic acid.
[6] The dispersion according to any one of [1] to [5], further comprising an organic phosphorus compound or a salt thereof and / or an organic sulfur compound or a salt thereof.

  The inorganic particle dispersion of the present invention is one that increases the proportion of inorganic particles while maintaining its transparency, and further increases the viscosity of the dispersion medium, and thus has good thixotropy while maintaining its fluidity, Excellent practicality.

The inorganic particle dispersion of the present invention includes inorganic particles and a dispersion medium, the viscosity of the dispersion medium at a temperature of 25 ° C. is 6 mPa · s or more, and the viscosity change rate represented by the following formula is 2.0 or more. It is characterized by being.
Viscosity change rate = (shear viscosity at a liquid temperature of 25 ° C. at a shear rate of 1 s ⁻¹ ) / (shear viscosity at a liquid temperature of 25 ° C. at a shear rate of 100 s ⁻¹ )
The total light transmittance of the inorganic particle dispersion is preferably 55% or more, more preferably 60% or more, still more preferably 65% or more, and the higher the better, for example, 99% or less, and further 80% or less. It is also acceptable.

  The total light transmittance can be measured according to JIS K7361-1 (1997) using a turbidimeter (for example, “NDH-5000” manufactured by Nippon Denshoku Industries Co., Ltd.).

  The concentration of the inorganic particles is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 75% by mass or more, preferably 99% by mass or less, more preferably 95% by mass in 100% by mass of the dispersion. % Or less, more preferably 90% by mass or less.

In the inorganic particle dispersion, the viscosity change rate (shear viscosity at a shear rate of 1 s ⁻¹ at a liquid temperature of 25 ° C.) / (Shear viscosity at a shear rate of 100 s ⁻¹ at a liquid temperature of 25 ° C.) is 2.0 or more. Preferably it is 3.0 or more, More preferably, it is 4.0 or more, Preferably it is 50.0 or less, More preferably, it is 30.0 or less, More preferably, it is 15.0 or less.

The shear viscosity of the inorganic particle dispersion at a shear rate of 1 s ⁻¹ or 100 s ⁻¹ at a liquid temperature of 25 ° C. can be measured using a cone plate viscometer, and specifically measured by the following method. it can.
[Measurement method of shear viscosity]
The inorganic particle dispersion is allowed to stand in an air atmosphere at 25 ° C. for 24 hours. Next, in a cone plate viscometer, the measurement part is adjusted to 25 ° C., and the inorganic particle dispersion which has been allowed to stand for 24 hours in an air atmosphere at 25 ° C. is accommodated in the measurement part. The cone plate is rotated in a state where the gap between the cone portion of the cone plate and the measurement portion is filled with the inorganic particle dispersion, and the shear rate is maintained at 1 s ⁻¹ or 100 s ⁻¹ . As the cone plate, any one of the following cone plates A, B, and C is used according to the viscosity of the inorganic particle dispersion.
Cone plate A Diameter 25 mm, cone angle 0.1 rad
Cone plate B diameter 25mm, cone angle 0.02rad
Cone plate C Diameter 50 mm, cone angle 0.02 rad
Shear viscosity of the inorganic particle dispersion at a shear rate of 1s ^-1 or 100s ^-1 of shear rate of the cone-plate viscosity at the time of the lapse of 5 minutes from the start of keeping the 1s ^-1 or 100s ^-1, at a liquid temperature 25 ° C. And

The viscosity of the inorganic particle dispersion is preferably 2,500 mPa · s or more, more preferably 5,000 mPa · s or more, and even more preferably 10,000 mPa when measured under conditions of a liquid temperature of 25 ° C. and a shear rate of 1 s ^−1. It is s or more, preferably 1,000,000 mPa · s or less, more preferably 500,000 mPa · s or less.

The density of the inorganic particle dispersion is preferably 1.2 g / cm ³ or more, more preferably 1.5 g / cm ³ or more, and further preferably 2 g / cm ³ or more when measured at a liquid temperature of 25 ° C. , Preferably 7 g / cm ³ or less, more preferably 6 g / cm ³ or less, and even more preferably 5.5 g / cm ³ or less.

If the said inorganic particle dispersion has fluidity | liquidity in 25 degreeC, it can be said that it has fluidity | liquidity sufficient practically. The fluidity at 25 ° C. can be evaluated by the following method.
[Evaluation method of fluidity]
45 mL of the inorganic particle dispersion is poured into a test tube having an outer diameter of 30 mm, and left in a 25 ° C. atmosphere for 24 hours in a vertical state. If necessary, heat until the minimum fluidity necessary to pour the sample into the test tube is obtained. Subsequently, after confirming that the sample is adjusted to a temperature of 25 ° C., the sample is kept horizontal for 5 seconds and the state is observed. The case where the sample moves is evaluated as fluid, and the case where the sample does not move is evaluated as not fluid.

The inorganic particles contained in the inorganic particle dispersion are preferably metal particles or metal oxide particles, and are preferably metal oxide particles. Examples of the metal constituting the inorganic particles include Ti, Al, Zr, In, Zn, Sn, La, Y, Ce, Mg, Ba, and Ca, and the refractive index of the inorganic particles (particularly metal oxide particles). From the viewpoint of increasing the thickness, at least one selected from the group consisting of Ti, Al, Zr, Zn, Sn and Ce (particularly Zr) is preferable. When the inorganic particles are metal oxide particles, the metal oxide may be a single metal oxide, a solid solution of two or more oxides, or a composite oxide. May be. Examples of the single metal oxide include aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), zirconium oxide (ZrO ₂ ), indium oxide (In ₂ O ₃ ), zinc oxide (ZnO), and tin oxide. (SnO ₂ ), lanthanum oxide (La ₂ O ₃ ), yttrium oxide (Y ₂ O ₃ ), cerium oxide (CeO ₂ ), and magnesium oxide (MgO) are included. Examples of the solid solution of two or more oxides include indium tin oxide (ITO) and tin antimony oxide (ATO). Examples of the composite oxide include barium titanate (BaTiO ₃ ), perovskite (CaTiO ₃ ), spinel (MgAl ₂ O ₄ ), and the like.

  The crystallite size of the inorganic particles is preferably 20 nm or less, more preferably 15 nm or less, still more preferably 10 nm or less, and usually 1 nm or more. As the crystallite size is smaller, the transmittance of the inorganic particle dispersion can be improved.

The crystal structure of the inorganic particles is preferably cubic, tetragonal, monoclinic, or the like, and a plurality of crystal structures may exist. From the viewpoint of improving the refractive index, 50% or more of the entire crystal structure is preferably tetragonal. Further, the ratio of tetragonal to monoclinic crystals (tetragonal / monoclinic) is preferably 0.8 or more, more preferably 1.0 or more, and still more preferably 1.1 or more. Tetragonal crystals can be used alone.
The crystallite diameter and crystal structure of the inorganic particles can be specified by an X-ray diffraction method.

  The inorganic particles may be granular, oval, cubic, cuboid, pyramid, needle, column, rod, cylinder, flake, plate, flake, etc., dispersibility in dispersion medium From the viewpoint of the above, it is preferably spherical, granular, or columnar.

The volume average particle diameter (d _v ) of the inorganic particles is preferably 50 nm or less, more preferably 30 nm or less, still more preferably 20 nm or less, preferably 1 nm or more, more preferably 5 nm or more. When the volume average particle diameter of the inorganic particles is in the above range, the transparency of the inorganic particle dispersion is easily increased.
The volume average particle diameter (d _v ) of the inorganic particles can be measured by a dynamic light scattering method.

The number average primary particle diameter of the inorganic particles (d _n) is a number basis, preferably 50nm or less, more preferably 30nm or less, more preferably 20nm or less, preferably 1nm or more, more preferably 5nm or more is there. When the number average primary particle diameter of the inorganic particles is in the above range, the transparency of the inorganic particle dispersion is easily improved.
The number average primary particle diameter (d _n ) of the inorganic particles is determined using a transmission electron microscope (TEM), a field emission transmission electron microscope (FE-TEM), a field emission scanning electron microscope (FE-SEM), etc. It can be determined by magnifying and selecting 100 particles at random, measuring the length in the major axis direction, and calculating the arithmetic average thereof.

A volume average particle diameter of the inorganic particles (d _v), the ratio of the number-average primary particle diameter _{(d n) (d v /} d n) is preferably 10 or less, more preferably 5 or less, more preferably 3 or less Preferably, it is 1 or more.

  As the inorganic particles, any of inorganic particles surface-modified with a surface modifier (hereinafter sometimes referred to as “coated inorganic particles”) and non-surface-modified inorganic particles can be used. Good. When the inorganic particles are coated inorganic particles, the mass of the coated inorganic particles includes the mass of the surface modifier.

  The inorganic particle dispersion preferably contains at least one of an organic acid, a silane coupling agent, a surfactant and a titanium coupling agent as a surface modifier of the inorganic particles, and preferably contains at least an organic acid. Dispersibility can be improved by including an organic acid. Usually, high-density inorganic particles differ greatly from the dispersion medium in terms of density and hydrophilicity / hydrophobicity, so it is difficult to disperse at high concentrations, but surface modification can disperse at high concentrations. It becomes easy and it becomes easy to improve thixotropy.

  As the organic acid, a compound having a carboxy group (hereinafter sometimes referred to as “carboxylic acid compound”) is preferable, and the carboxylic acid compound is a cation (for example, a metal cation such as an alkali metal cation or an alkaline earth metal cation; A salt may be formed with a molecular cation such as an ammonium ion). The organic acid preferably covers the surface of the inorganic particles. Since the organic acid is chemically bonded to the inorganic particles or attached to the inorganic particles in the form of a carboxylic acid or a salt, the “coating” in the present invention means that the organic acid or the like is chemically attached to the inorganic particles. And a state in which an organic acid or the like is physically attached to the metal oxide. Further, when an organic acid is used as the surface modifier, the organic acid can exhibit a function as a component of the composition and a function as a surface modifier.

  Examples of the carboxylic acid compound include (meth) acrylic acids; one or more substituents selected from the group consisting of ester groups, ether groups, amide groups, thioester groups, thioether groups, carbonate groups, urethane groups, and urea groups (hereinafter, A carboxylic acid having a “specific substituent” in some cases; a linear carboxylic acid (such as a linear aliphatic carboxylic acid, preferably a linear saturated aliphatic carboxylic acid), a branched carboxylic acid ( A branched aliphatic carboxylic acid, preferably a branched saturated aliphatic carboxylic acid), a cyclic carboxylic acid (an alicyclic carboxylic acid, preferably an alicyclic carboxylic acid having no unsaturated double bond, etc.) and A compound having 4 to 20 carbon atoms and having one or more (preferably one) carboxy groups selected from aromatic carboxylic acids and the like is preferably employed.

Examples of the carboxylic acid compound include (meth) acrylic acids (for example, (meth) acryloxy C _1-6 alkylcarboxylic acid such as acrylic acid, methacrylic acid, 3-acryloxypropionic acid, etc.); C _3-9 aliphatic dicarboxylic acid Half esters of acid with (meth) acryloxy C _1-6 alkyl alcohol (for example, 2-acryloxyethyl succinic acid, 2-methacryloxyethyl succinic acid, etc.), (meth) of C _5-10 alicyclic dicarboxylic acid Half esters with acryloxy C _1-6 alkyl alcohol (for example, 2-acryloxyethyl hexahydrophthalic acid, 2-methacryloxyethyl hexahydrophthalic acid, etc.), (meth) acryloxy C of C _8-14 aromatic dicarboxylic acid _1-6 alkyl alcohol by half esters (e.g., 2-acryloyloxyethyl phthalate, 2- Carboxylic acid having an ester group such as tacryloxyethylphthalic acid; linear carboxylic acid such as butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, stearic acid Acids: Pivalic acid, 2,2-dimethylbutyric acid, 3,3-dimethylbutyric acid, 2,2-dimethylvaleric acid, 2,2-diethylbutyric acid, 3,3-diethylbutyric acid, 2-methylhexanoic acid, 2-ethyl Branched chain carboxylic acids such as hexanoic acid, 3-methylhexanoic acid, 3-ethylhexanoic acid, 2-methylheptanoic acid, 4-methyloctanoic acid and neodecanoic acid; cyclic carboxylic acids such as naphthenic acid and cyclohexanedicarboxylic acid; Etc.

  As the carboxylic acid compound, it is preferable to use at least (meth) acrylic acids; or a carboxylic acid having a specific substituent. Hereinafter, the (meth) acrylic acids and the carboxylic acid having a specific substituent may be collectively referred to as “first carboxylic acid compound”.

  As a 1st carboxylic acid compound, 1 type (s) or 2 or more types can be used, What is necessary is just a carboxylic acid which is (meth) acrylic acid or has 1 or more types of specific substituents. The carboxylic acid having a specific substituent may have a plurality of the same or different specific substituents, and may further have a substituent other than the specific substituent. As the specific substituent, an ester group, an ether group or an amide group is preferable, and an ester group or an ether group is more preferable. The number of specific substituents may be one or more per molecule, and the upper limit is not particularly limited, but is preferably 20 or less, more preferably 10 or less, and even more preferably 5 or less.

  A commercially available product may be used as the first carboxylic acid compound, or a compound synthesized by a known synthesis method may be used. Examples of the synthesis method include a method of obtaining an ester compound (such as a half ester compound) by a reaction of various alcohol compounds with a dibasic acid or an acid anhydride, and an ester compound (half half) by a reaction of an epoxy compound or a glycidyl compound with a dibasic acid. Ester compound, etc.), a method of obtaining an amide compound by a reaction of an amine compound and a dibasic acid or acid anhydride, a method of obtaining a thioester compound by a reaction of a thiol compound and a dibasic acid or acid anhydride, etc. it can.

  The α carbon of the carboxy group of the first carboxylic acid compound may be any of secondary carbon, tertiary carbon, quaternary carbon, or aromatic carbon. The number of carboxy groups contained in the first carboxylic acid compound may be one or more, but preferably 3 or less, more preferably 2 or less, and even more preferably 1 from the viewpoint of suppressing cross-linking between particles. It is.

  The first carboxylic acid compound is preferably acrylic acid, 2-acryloxyethyl succinic acid, 2-acryloxyethyl hexahydrophthalic acid, 2-acryloxyethyl phthalic acid, more preferably 2-acryloxy. Examples include ethyl succinic acid.

  The content of the first carboxylic acid compound is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, further preferably 2 parts by mass or more, even more with respect to 100 parts by mass of the inorganic particles. The amount is preferably 5 parts by mass or more, particularly preferably 10 parts by mass or more, most preferably 15 parts by mass or more, preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and further preferably 20 parts by mass or less. The more the first carboxylic acid compound is, the more the dispersibility of the inorganic particles can be improved.

The inorganic particle dispersion preferably contains two or more carboxylic acid compounds as organic acids. The coated metal oxide particles coated with two or more carboxylic acid compounds have extremely good dispersibility in various media and can be applied to various uses. In particular, it is remarkably useful in applications for forming a precision fine structure typified by a resist, and it can be expected that the dispersion unevenness and development residue can be improved.
When two or more carboxylic acid compounds are included, it is preferable to include at least (meth) acrylic acids and a carboxylic acid having a specific substituent (first carboxylic acid compound). The first carboxylic acid compound and the linear carboxylic acid are included. Compounds having 4 to 20 carbon atoms having a carboxy group that is one or more (preferably one) selected from acids, branched carboxylic acids, cyclic carboxylic acids, aromatic carboxylic acids, etc. It is more preferable to include a “second carboxylic acid compound”. In this case, it is preferable that the first carboxylic acid compound and the second carboxylic acid compound cover the inorganic particles.

  As a 2nd carboxylic acid compound, 1 type (s) or 2 or more types can be used, Branched carboxylic acid is preferable, 2-methylhexanoic acid, 2-ethylhexanoic acid, 3-methylhexanoic acid, 3- Ethylhexanoic acid is more preferred. By using the branched carboxylic acid, it becomes possible to efficiently suppress aggregation of the metal oxide particles.

  The content of the second carboxylic acid compound is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, further preferably 2 parts by mass or more, with respect to 100 parts by mass of the inorganic particles. Preferably, it may be 30 parts by mass or less, more preferably 25 parts by mass or less, further preferably 20 parts by mass or less, still more preferably 10 parts by mass or less, and particularly preferably 5 parts by mass or less. The greater the content of the second carboxylic acid compound, the higher the dispersibility of the inorganic particles.

  When both the first carboxylic acid compound and the second carboxylic acid compound are included as the organic acid, the mass ratio of the contents of the first and second carboxylic acid compounds (first carboxylic acid compound / second carboxylic acid) The compound is preferably 1/99 to 99/1, more preferably 50/50 to 99/1, even more preferably 60/40 to 97/3, and particularly preferably 65/35 to 90/10. Good. When the content of the first and second carboxylic acid compounds is within the above range, the affinity with the dispersion medium having various properties such as hydrophilicity and hydrophobicity can be easily improved.

The difference (pKa ₁ -pKa ₂ ) between the pKa (pKa ₁ ) of the first carboxylic acid compound and the pKa (pKa ₂ ) of the second carboxylic acid compound is preferably −0.1 or less, more preferably −0 .2 or less, more preferably -0.3 or less. The smaller the difference between pKa ₁ and pKa ₂ , the easier it is to replace the first carboxylic acid compound with the second carboxylic acid compound, so that the inorganic particles coated with the first and second carboxylic acid compounds It becomes easy to obtain.

The pKa ₁ of the first carboxylic acid compound is preferably 4.8 or less, more preferably 4.7 or less, still more preferably 4.6 or less, may be 2 or more, and is further 3 or more. May be. The pKa ₂ of the second carboxylic acid compound is, for example, about 4.0 to 6.0, preferably about 4.2 to 5.5, and more preferably about 4.5 to 5.0. The value calculated by the computational chemistry software ACD / pKa version 10.01 (Advanced Chemistry Development, Inc.) can be adopted as the pKa of the carboxylic acid compound.

  The carboxylic acid compound (for example, the first and second carboxylic acid compounds) preferably has a polymerizable double bond (particularly a polymerizable carbon-carbon double bond). If the inorganic particles are coated with a carboxylic acid compound having a polymerizable double bond, there will be a polymerizable double bond on the surface of the inorganic particles, and polymerization with other ingredients will be possible. It is easy to maintain a good dispersion state even in a cured product without causing problems such as bleed out and bleeding. When the first and second carboxylic acid compounds are included, either the first or second carboxylic acid compound may have a polymerizable double bond, and both the first and second carboxylic acid compounds are It may have a polymerizable double bond, and it is preferable that the first carboxylic acid compound has a polymerizable double bond and the second carboxylic acid compound does not have a polymerizable double bond. Moreover, when using 2 or more types of 1st or 2nd carboxylic acid compounds, at least 1 type should just have a polymerizable double bond among 1st or 2nd carboxylic acid compounds.

  The total content of carboxylic acid compounds (when the first and second carboxylic acid compounds are included, the total content of the first and second carboxylic acid compounds) is preferably 0.2 in 100 parts by mass of the inorganic particle dispersion. May be at least 1 part by mass, more preferably at least 1 part by mass, even more preferably at least 2 parts by mass, even more preferably at least 5 parts by mass, particularly preferably at least 7 parts by mass, most preferably at least 10 parts by mass, Preferably it is 40 mass parts or less, More preferably, it is 35 mass parts or less, More preferably, it is 30 mass parts or less.

When the silane coupling agent is contained in the inorganic particle dispersion, it is also preferable that the inorganic particles are surface-modified with a silane coupling agent. When the inorganic particles are surface-modified with a silane coupling agent, not only the initial transmittance can be improved, but also the transmittance can be easily maintained for a long time. As the silane coupling agent may be used alone or in combination, a hydrolyzable group -Si-OR ⁹ (provided that, R ⁹ is methyl or ethyl) compounds having preferred. Examples of the silane coupling agent include a silane coupling agent having a functional group and alkoxysilane.

As a silane coupling agent having a functional group, the following formula (3):
_{[X- (CH 2) m]} 4-n -Si- (OR 9) n ... (3)
(Wherein, X is a functional group, R ⁹ is the same as above, m is an integer of 0 to 4, and n is an integer of 1 to 3).

  Examples of X include a vinyl group, an amino group, a (meth) acryloxy group, a mercapto group, and a glycidoxy group. Specific examples of the silane coupling agent include, for example, a silane coupling agent having a vinyl functional group X such as vinyltrimethoxysilane and vinyltriethoxysilane; 3-aminopropyltrimethoxysilane, 3-aminopropyltri Silane coupling in which the functional group X is an amino group such as ethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyltrimethoxysilane Agent: Functionality such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane Group X is (meta Silane coupling agent which is acryloxy group; Silane coupling agent whose functional group X is mercapto group such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane; 2- (3,4-epoxycyclohexyl) ethyl Functional groups X such as trimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane And a silane coupling agent which is a glycidoxy group.

  Examples of the alkoxysilane include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, propyltrimethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, etc. Alkyl group-containing alkoxysilane in which the alkyl group is directly bonded to the silicon atom of alkoxysilane; aromatic rings such as phenyltrimethoxysilane, diphenyldimethoxysilane, p-styryltrimethoxysilane are directly bonded to the silicon atom of alkoxysilane. Aryl group-containing alkoxysilanes;

  As the silane coupling agent, a silane coupling agent whose functional group X is a (meth) acryloxy group and an alkyl group-containing alkoxysilane are preferable, such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, hexyltri. Methoxysilane, octyltriethoxysilane, and decyltrimethoxysilane are more preferable.

  The amount (covering amount) of the silane coupling agent is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, further preferably 2 parts by mass or more, with respect to 100 parts by mass of the entire inorganic particles. More preferably, it is 4 parts by mass or more, preferably 30 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 15 parts by mass or less, still more preferably 12 parts by mass or less. By setting the content of the silane coupling agent in the above range, the refractive index of the inorganic particles can be maintained.

  When an organic acid and a silane coupling agent are included as the surface modifier, the mass ratio of the silane coupling agent to the organic acid (silane coupling agent / organic acid) is preferably 0.1 to 2.0, more preferably. It is 0.2 to 1.5, more preferably 0.3 to 0.95. When the amount of the silane coupling agent is within the above range, the dispersibility of the inorganic particles is good.

  As the surface modifier of the inorganic particles, a surfactant and / or a titanium coupling agent may be used. Examples of the surfactant include ionic surfactants such as anionic surfactants, cationic surfactants, and zwitterionic surfactants, and nonionic surfactants. Examples of anionic surfactants include fatty acid sodium such as sodium oleate, sodium stearate and sodium laurate, fatty acid such as fatty acid potassium and sodium fatty acid ester sulfonate; phosphoric acid such as sodium alkyl phosphate ester; alpha Examples thereof include olefins such as sodium olefin sulfonate; alcohols such as sodium alkyl sulfate; alkylbenzenes and the like. Examples of the cationic surfactant include alkyl methyl ammonium chloride, alkyl dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, and alkyl dimethyl benzyl ammonium chloride. Examples of the zwitterionic surfactant include carboxylic acid systems such as alkylaminocarboxylates; phosphate ester systems such as phosphobetaine. Nonionic surfactants include, for example, fatty acid series such as polyoxyethylene laurin fatty acid ester and polyoxyethylene sorbitan fatty acid ester; polyoxyethylene alkylphenyl ether; fatty acid alkanolamide and the like.

  Examples of the titanium coupling agent include isopropyl triisostearoyl titanate, isopropyl dimethacrylisostearoyl titanate, isopropyl tri (dodecyl) benzenesulfonyl titanate, neopentyl (diallyl) oxy-tri (dioctyl) phosphate titanate, neopentyl (diallyl). And oxy-trineododecanoyl titanate.

When the inorganic particles are modified with a surface modifier, the surface-modified inorganic particles (coated inorganic particles) may be those obtained by surface modification of the surface unmodified inorganic particles with the surface modifier. It may be synthesized by.
When synthesizing coated inorganic particles (especially surface-modified metal oxide particles) by hydrothermal synthesis, for example, a metal or metal oxide (especially metal oxide) can be generated by hydrothermal reaction in the presence of water. Hydrothermal reaction of a compound (hereinafter sometimes referred to as “inorganic particle precursor”) and a second carboxylic acid compound (however, the inorganic particle precursor and the second carboxylic acid compound may form a salt) Thus, the coated inorganic particles a coated with the second carboxylic acid compound can be produced (hydrothermal process), and at least a part of the second carboxylic acid compound covering the coated inorganic particles a By substituting with the first carboxylic acid compound (substitution step), the coated inorganic particles b coated with the first and second carboxylic acid compounds can be produced. Moreover, the covering type inorganic particle coat | covered with the 1st carboxylic acid compound can be manufactured by implementing a substitution process until all the 2nd carboxylic acid compounds are substituted by the 1st carboxylic acid compound.

  The inorganic particle precursor preferably includes at least one selected from Ti, Al, Zr, Zn, Sn, and Ce, more preferably includes Ti and Zr, and further preferably includes Zr.

  The inorganic particle precursor is preferably a compound that generates a metal oxide by a hydrothermal reaction. Specifically, various metals and hydroxides of various metals, chlorides, oxychlorides, oxyacetates, oxy Nitrate, sulfate, acetate, organic acid salt, alkoxide and the like are included, and a salt of a metal and a second carboxylic acid compound may be used. For example, in the case of zirconium, zirconium hydroxide; zirconium chloride; zirconium oxychloride; zirconium oxyacetate, zirconium oxynitrate; zirconium sulfate; zirconium octoate, zirconium 2-ethylhexanoate, zirconium oleate, zirconium acetate, zirconium stearate Zirconium laurate; zirconium alkoxides such as tetrabutoxyzirconium and the like. Examples of titanium include titanium hydroxide; titanium chloride; titanium oxychloride, titanium oxyacetate, titanium oxynitrate; titanium sulfate; titanium octoate, titanium oleate, titanium acetate, titanium stearate, titanium laurate; Examples thereof include titanium alkoxides such as butoxy titanium (for example, tetra-n-butoxy titanium).

  Examples of the second carboxylic acid compound include the above-described linear carboxylic acid, branched carboxylic acid, cyclic carboxylic acid, and aromatic carboxylic acid. Specifically, hexanoic acid, heptanoic acid, octanoic acid , Nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, stearic acid and other linear carboxylic acids; 2-ethylhexanoic acid, 2-methylheptanoic acid, 4-methyloctanoic acid, neodecanoic acid, pivalic acid, 2,2 -Branched carboxylic acids such as dimethylbutyric acid, 3,3-dimethylbutyric acid, 2,2-dimethylvaleric acid, 2,2-diethylbutyric acid, 3,3-diethylbutyric acid; cyclic such as naphthenic acid and cyclohexanedicarboxylic acid A carboxylic acid etc. can be mentioned.

As the combination of the inorganic particle precursor and the second carboxylic acid compound to be subjected to the hydrothermal reaction (however, the inorganic particle precursor and the second carboxylic acid compound may form a salt), the following (i) It is preferable that at least 1 sort (s) chosen from-(iii) is included.
(I) salt of inorganic particle precursor and second carboxylic acid compound (ii) metal salt of second carboxylic acid compound (iii) inorganic particle precursor and second carboxylic acid compound

  (I) Various metal chlorides (especially oxychlorides) and nitrates (especially oxynitric acid) salts by forming a salt between the inorganic particle precursor, the second carboxylic acid compound and the inorganic particle precursor. It is possible to use a water-soluble and highly corrosive raw material. Here, the salt includes a single type compound composed of a stoichiometric ratio of an inorganic particle precursor, a carboxylic acid, and an inorganic particle precursor, a composite salt, and an unreacted inorganic particle precursor or carboxylic acid. Also included are compositions that are present.

  The salt of the inorganic particle precursor and the second carboxylic acid compound is preferably a salt of the second carboxylic acid compound and the metal constituting the inorganic particle. The salt is a composition (hereinafter referred to as “carboxylic acid”) obtained by neutralizing the second carboxylic acid compound with an alkali metal and / or an alkaline earth metal to a degree of neutralization of 0.1 to 0.8. It may be referred to as “salt-containing composition”) and may be obtained by reacting the inorganic particle precursor.

  The neutralization degree is preferably 0.1 to 0.8, and more preferably 0.2 to 0.7. When the degree of neutralization is in the above range, salt formation is easy and the yield of the coated inorganic particles is also good. The alkali metal and / or alkaline earth metal used to obtain the carboxylate-containing composition is preferably a metal that forms a highly water-soluble carboxylate, more preferably an alkali metal, and even more preferably sodium and potassium. .

The ratio of the carboxylate-containing composition to the inorganic particle precursor is preferably 1 mol to 20 mol of carboxy group, more preferably 1.2 to 18 mol, relative to 1 mol of the inorganic particle precursor. 1.5 to 15 mol is more preferable.
When the carboxylate-containing composition and the inorganic particle precursor are reacted, it is preferable to mix aqueous solutions. The reaction temperature is not particularly limited as long as the aqueous solution can be maintained, but is preferably from room temperature to 100 ° C, more preferably from 40 ° C to 80 ° C.

  The salt obtained by reacting the carboxylate-containing composition and the inorganic particle precursor may be subjected to a hydrothermal reaction as it is, and insoluble by-products are removed by filtration or the like before the hydrothermal reaction. It is preferable to keep it.

(Ii) The metal salt of the second carboxylic acid compound is different from (i) in that it is already a salt (that is, a salt forming reaction is unnecessary). As the metal salt of the second carboxylic acid compound, a salt of the second carboxylic acid compound and at least one selected from Ti, Al, Zr, Zn, Sn, and Ce can be used.
Examples of the metal salt include titanium 2-ethylhexanoate, titanium 3,3-dimethylbutyrate, titanium octoate, titanium oleate, titanium stearate, titanium laurate, aluminum octoate, zirconium octoate, and 2-ethylhexanoic acid. Examples thereof include zirconium, zirconium oleate, zirconium stearate, zirconium laurate, zinc octoate, tin octoate, and cerium octoate.

  (Iii) Of the second carboxylic acid compound and inorganic particle precursor, the inorganic particle precursor includes the various metals and hydroxides, chlorides, oxychlorides, oxyacetates, and oxynitrates of the various metals described above. , Sulfate, acetate, organic acid salt, alkoxide and the like.

  The inorganic particle precursor and the second carboxylic acid compound are preferably mixed in the presence of water. At this time, by carrying out under heating or reduced pressure, low boiling point compounds (ammonia, acetic acid, etc.) contained in the inorganic particle precursor can be driven out of the system, and the pressure increase in the hydrothermal reaction in the next step can be increased. Can be suppressed. You may mix in the solution which added the below-mentioned organic solvent.

  When the inorganic particle precursor and the second carboxylic acid compound are subjected to a hydrothermal reaction, if the viscosity is high and the hydrothermal reaction does not proceed efficiently, the inorganic particle precursor and / or the second carboxylic acid compound An organic solvent exhibiting good solubility may be added.

  As the organic solvent, hydrocarbons, ketones, ethers, alcohols and the like can be used. From the viewpoint of suppressing vaporization during the hydrothermal reaction, the boiling point of the organic solvent under normal pressure is preferably 120 ° C. or higher, more preferably 180 ° C. or higher, and further preferably 210 ° C. or higher. Specifically, decane, dodecane, tetradecane, octanol, decanol, cyclohexanol, terpineol, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2,3- Examples include butanediol, hexanediol, glycerin, methanetrimethylol, toluene, xylene, trimethylbenzene, dimethylformamide (DMF), dimethylsulfoxide (DMSO) and the like, and dodecane and tetradecane are preferable.

When separated into two layers by the addition of the organic solvent, a surfactant or the like may be added to obtain a homogeneous phase state or a suspension emulsified state. I can do it.
The composition may contain a sufficient amount of water derived from the raw material, but if there is no or little water contained in the raw material, it is necessary to add water before subjecting it to a hydrothermal reaction. is there.

The amount of water present in the hydrothermal reaction system is 4/1 to 100 in terms of the number of moles of water relative to the number of moles of inorganic particle precursors present in the system (number of moles of water / number of moles of inorganic particle precursor). / 1 is preferable, and 8/1 to 50/1 is more preferable. When the water content is in the above range, the time required for the hydrothermal reaction can be suppressed, and the particle size of the resulting inorganic particles can be suppressed.
It is preferable to replace the space of the reaction vessel with an inert gas such as nitrogen because side reactions due to oxidation of the organic carboxylic acid or the added organic solvent are suppressed.

The pressure during the hydrothermal reaction is preferably 0.1 MPaG, more preferably 0.2 MPaG, for example, 2 MPaG or less. When the pressure is in the above range, the reaction easily proceeds, and the particle size and crystal system of the inorganic particles can be easily controlled.
The reaction temperature is preferably 200 ° C. or lower, more preferably 180 ° C. or lower in view of the saturated vapor pressure of water, and preferably 100 ° C. or higher, more preferably 120 ° C. or higher from the viewpoint of suppressing the reaction time. . In addition, since it will become a high voltage | pressure before reaching sufficient reaction temperature when it is made into a pressurized state before a heating, it is not preferable to pressurize more than a normal pressure before a heating.
The reaction time can be adjusted from the relationship between the reaction temperature and pressure and the yield, and is usually 0.1 to 50 hours, preferably 1 to 20 hours.

  By the hydrothermal reaction, coated inorganic particles coated with the second carboxylic acid compound can be obtained and may be further purified. For example, the coated inorganic particles can be filtered and then dissolved in a solvent such as toluene, the insoluble matter can be filtered off, and the solvent such as toluene can be removed by concentration under reduced pressure.

It is preferable to use a basic compound during the hydrothermal reaction. The basic compound is not particularly limited as long as it shows basicity when dissolved in water, and any form such as Bronsted base or Lewis base may be used. Among these, at least one basic compound selected from alkali metal salts, alkaline earth metal salts and primary to tertiary amines is preferable. Alkali metal or alkaline earth metal hydroxides, carboxylic acid alkalis are preferable. Metal salts and primary to tertiary amines are more preferable, and alkali metal hydroxides and primary to tertiary amines are particularly preferable. The presence of the basic compound improves the yield of the produced coated inorganic particles a. Furthermore, a wide variety of carboxylic acids can be used as raw materials, and coated inorganic particles a coated with organic groups of a kind that were difficult to produce by conventional methods can be obtained.
The amount of the basic compound is preferably 0.03 mol or more and 1.5 mol or less with respect to 1 mol of the metal oxide precursor used in the step. By adding the basic compound in the above range, the yield of the coated inorganic particles a is further improved.

  The first and second carboxylic acid compounds were coated by substituting at least part of the second carboxylic acid compound of the coated inorganic particles a obtained by the hydrothermal reaction with the first carboxylic acid compound. Coated inorganic particles b are obtained. In order to replace the second carboxylic acid compound with the first carboxylic acid compound, a mixture (particularly, a mixed solution) containing the coated inorganic particles a and the first carboxylic acid compound may be stirred. The mass ratio of the first carboxylic acid compound to the coated inorganic particles a (first carboxylic acid compound / coated inorganic particles a) is preferably 5/100 to 200/100. More preferably, it is 10/100 to 150/100.

  As the solvent used for the preparation of the mixture (particularly the mixed solution), the solvent used in the hydrothermal reaction may be used as it is, or another solvent may be used. Solvents include alcohols such as methanol, ethanol, n-propanol, isopropanol, and ethylene glycol; ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethyl acetate, propyl acetate, propylene glycol monomethyl ether acetate, 3-methoxypropionic acid Esters such as methyl; ethers such as ethylene glycol monomethyl ether and diethylene glycol monobutyl ether; modified ethers such as propylene glycol monomethyl ether acetate (preferably ether-modified and / or ester-modified ethers, more preferably ether-modified and / or Ester-modified alkylene glycols); benzene, toluene, xylene, ethylbenzene, trimethylbenzene, Hydrocarbons such as sun, cyclohexane, methylcyclohexane, ethylcyclohexane, mineral spirits; halogenated hydrocarbons such as dichloromethane and chloroform; amides such as dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone; water; Oils such as mineral oil, vegetable oil, wax oil, silicone oil and the like can be mentioned. When the coated inorganic particles b are prepared in such a solvent, the affinity in the composition is further improved, and dispersion unevenness can be further prevented.

  The stirring temperature is preferably 0 to 100 ° C, more preferably 10 to 70 ° C, still more preferably 20 to 50 ° C, and the concentration of the coated inorganic particles a in the mixed solution is preferably 5 to 80% by mass, more Preferably it is 10-60 mass%. Further, it is possible to carry out processing without solvent or at a higher concentration using a ball mill or the like. The reaction time is preferably 10 minutes to 5 hours, more preferably 20 minutes to 2 hours.

  When the coated inorganic particles b are prepared in a solvent, the coated inorganic particles b are preferably dissolved in the solvent. In this case, the coated inorganic particles and the solvent can be separated by concentration or the like. The coated inorganic particles may be precipitated by adding a suitable poor solvent (for example, an aliphatic hydrocarbon solvent such as hexane). The precipitate can be separated from the solvent by an appropriate solid-liquid separation method (filtration method, centrifugal method, etc.). It is also possible to combine the concentration with the addition of a poor solvent.

  The coated inorganic particles of the present invention obtained by the above method are preferably washed. By washing, the by-product, the unreacted first carboxylic acid compound, and the substituted second carboxylic acid compound are removed from the composition, and there is no adverse effect when used in various applications described later. . The washing solvent is not particularly limited, but acetone, hexane, heptane, octane, methanol, and ethanol are preferably used.

  When using an organic acid and a silane coupling agent as the surface modifier for the inorganic particles, for example, the coated inorganic particles a obtained by the hydrothermal reaction and the silane coupling agent are mixed, and the resulting mixture is 65 to 100. It is good to make it react for about 0.5-2h on the conditions of (degreeC), obtain a dispersion liquid, and to use the mixture (mixture liquid) containing this dispersion liquid and the 1st carboxylic acid compound as a raw material of a substitution process.

  The dispersion medium used in the inorganic particle dispersion of the present invention may have a viscosity at a temperature of 25 ° C. of 6 mPa · s or more. The viscosity of the dispersion medium at a temperature of 25 ° C. is preferably 8 mPa · s or more, more preferably 9 mPa · s or more, preferably 5000 mPa · s or less, more preferably 3000 mPa · s or less, and further preferably 2500 mPa · s or less. is there.

  From the viewpoint of enhancing the transparency of the inorganic particle dispersion, the refractive index of the dispersion medium is preferably 1.1 or more, more preferably 1.3 or more, still more preferably 1.4 or more, and even 2 or less. It may be 1.8 or less.

  As the dispersion medium, one type or two or more types can be used. At least a compound containing two or more aromatic rings in one molecule or a compound containing one or more bridging rings in one molecule (hereinafter, these are generic names) It may be referred to as a “specific ring-containing compound”). The specific ring-containing compound preferably has one or more polymerizable double bonds, and more preferably has one or more (meth) acryloyl groups.

The aromatic ring may be an aromatic hydrocarbon ring or an aromatic heterocyclic ring, and is preferably an aromatic hydrocarbon ring such as a benzene ring or a naphthalene ring. Examples of the compound containing two or more aromatic rings in one molecule include biphenylmethyl (meth) acrylate, o-phenylphenoxyethyl (meth) acrylate, m-phenoxybenzyl (meth) acrylate, ethoxylated phenylphenol (meth) acrylate ( The total of oxyethylene units is preferably 1-30, more preferably 2-20, and ethoxylated cumylphenol (meth) acrylate (the total of oxyethylene units is preferably 1-30, more preferably 2-20. ), 2- (1-naphthyloxy) ethyl (meth) acrylate, 2- (2-naphthyloxy) ethyl (meth) acrylate, naphthyloxypolyethylene glycol (meth) acrylate, N-vinylcarbazole, etc. 1 double bond and 2 or more aromatic rings Compound: divinylnaphthalene, propoxylated ethoxylated bisphenol A di (meth) acrylate (total of oxyethylene units is preferably 2 to 30, more preferably 5 to 20. Total of oxypropylene units is preferably 2 to 30, More preferably 5-20), ethoxylated bisphenol A di (meth) acrylate (total of oxyethylene units is preferably 2-40, more preferably 3-30), ethoxylated bisphenol F di (meth) acrylate (oxy) The total of ethylene units is preferably 2-40, more preferably 3-30), propoxylated bisphenol A di (meth) acrylate (total of oxypropylene units is preferably 2-40, more preferably 3-30) 9,9-bis [4- (2- (meth) acryloxyethoxy ) Phenyl] fluorene, diphenic acid diallyl 2,3 naphthalene compounds comprising two or more two and aromatic rings polymerizable double bonds in one molecule such as dicarboxylic acid diallyl ester; and the like.
R ^x1 —O— (R ^x2 —O—) _n -unit (R ^x1 represents a phenylphenyl group, a cumylphenyl group, a naphthyl group or a (meth) acryloyl group. R ^x2 represents an ethylene group or a propylene group. N represents an integer, and when n is 2 or more, R ^x2 may be the same or different, and R ^x1- (O) _tx -L ^x _-unit (tx is 0 or 1). L ^x represents a single bond, a linking group represented by any of formulas (a1) to (a3) described later, or a linking group represented by formulas (a1) to (a3) described later. A linking group in which two or more of them are combined.) May be substituted, and R ^x1 —O— (CH ₂ CH ₂ —O—) _nx unit (nx represents an integer of 1 to 30). Preferably there is.

  Examples of the bridge ring include a saturated or unsaturated bridge ring, and a saturated bridge ring is preferable. Examples of the compound containing one or more bridging rings in one molecule include compounds having one polymerizable double bond and one bridging ring in one molecule such as isobornyl (meth) acrylate; A compound containing two polymerizable double bonds and one bridging ring in one molecule, such as meth) acrylate, etc., and the like, and one molecule containing one polymerizable double bond and one bridging ring Compounds are preferred.

  The content of the specific ring-containing compound is preferably 90 parts by mass or more, more preferably 95 parts by mass or more, particularly preferably 99 parts by mass or more, and the upper limit is 100 parts by mass in the total 100 parts by mass of the dispersion medium. .

  The dispersion medium may contain other solvents and / or monomers in addition to the specific ring-containing compound. As said solvent, 1 type (s) or 2 or more types can be used, It may be the same as that of the solvent used for preparation of the said liquid mixture, or may differ, and it is the above-mentioned alcohol; ketones; ester; ether Modified ethers (preferably ether-modified and / or ester-modified ethers, more preferably ether-modified and / or ester-modified alkylene glycols); hydrocarbons; halogenated hydrocarbons; amides; water; Can be used. From the viewpoint of handleability, a solvent having a boiling point of 40 ° C. or more and 250 ° C. or less at normal pressure (1013 hPa) is preferable.

As said monomer, 1 type (s) or 2 or more types can be used, A monofunctional monomer and a crosslinkable monomer are mentioned.
The monofunctional monomer may be a compound having one polymerizable carbon-carbon double bond, and one or more may be used. (Meth) acrylic acid ester; styrene, p- Styrenic monomers such as tert-butyl styrene, α-methyl styrene, m-methyl styrene, p-methyl styrene, p-chloro styrene, p-chloromethyl styrene; carboxy group-containing monomers such as (meth) acrylic acid Body; hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate, 3-hydroxy-2-hydroxypropyl (meth) acrylate, and 3-phenoxy-2-hydroxypropyl (meth) acrylate. Specific examples of the (meth) acrylic acid ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth). (Meth) acrylic acid alkyl esters such as acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and lauryl (meth) acrylate; (meth) acrylic acid cycloalkyl esters such as cyclohexyl (meth) acrylate; 2 , 4-Dibromo-6-sec-butylphenyl (meth) acrylate, 2,4-dibromo-6-isopropylphenyl (meth) acrylate, phenyl (meth) acrylate, 2,4,6-tribromophenyl (meth) acrylate , Pentabromo (Meth) acrylic acid aryl esters such as phenyl (meth) acrylate; (meth) acrylic acid aralkyl esters such as benzyl (meth) acrylate and pentabromobenzyl (meth) acrylate; phenoxyethyl (meth) acrylate, phenoxy-2-methyl Ethyl (meth) acrylate, 2,4,6-tribromophenoxyethyl (meth) acrylate, 2,4-dibromophenoxyethyl (meth) acrylate, 2-bromophenoxyethyl (meth) acrylate, 1-naphthyloxyethyl (meth) ) (Meth) acrylic acid having an aryloxy unit such as acrylate, 2-naphthyloxyethyl (meth) acrylate, phenoxy-2-methylethyl (meth) acrylate, phenoxyethoxyethyl (meth) acrylate, etc. Ter; (meth) acrylic acid ester having arylthiooxy group such as phenylthioethyl (meth) acrylate, 1-naphthylthioethyl (meth) acrylate, 2-naphthylthioethyl (meth) acrylate; methoxypolyethylene glycol (meth) Examples thereof include alkylene glycol mono (meth) acrylates such as acrylate and phenoxypolyethylene glycol (meth) acrylate; (meth) acrylic acid esters having a glycidyl group such as glycidyl (meth) acrylate.
R ^y1 —O— (R ^y2 —O—) _n ^-unit (R ^y1 represents a methyl group or a phenyl group. R ^y2 represents an ethylene group. N represents an integer) contained in the above compound. _{^{, R y1 - (O) ty}} -L y - units (ty represents an integer of 0 or 1, L ^y represents a single bond, a linking group represented by any one of the later-described formula (a1) ~ formula (a3) Or a linking group represented by a combination of two or more of the linking groups represented by the formulas (a1) to (a3) described later), and R ^y1 —O— (CH ₂ CH ₂ —). O-) _ny -unit (ny represents an integer of 1 to 30) is preferable.

The crosslinkable monomer may be a compound containing a plurality of carbon-carbon double bonds. As this crosslinkable monomer, 1 type (s) or 2 or more types can be used, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di ( (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, tetramethylene glycol di (meth) acrylate Alkylene glycol poly (meth) acrylate such as neopentyl glycol di (meth) acrylate, neopentyl glycol poly (meth) acrylate such as dineopentyl glycol di (meth) acrylate Trimethylolpropane tri (meth) acrylate, ethoxylated (3) trimethylolpropane tri (meth) acrylate, propoxylated (3) trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, etc. Trimethylolpropane poly (meth) acrylate; glyceryl poly (meth) acrylate such as glyceryl tri (meth) acrylate, ethoxylated glyceryl tri (meth) acrylate; pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ethoxy Pentaerythritol tetra (meth) acrylate, propoxypentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate Polyfunctional (meth) acrylates such as pentaerythritol poly (meth) acrylate such as dipentaerythritol hexa (meth) acrylate; polyfunctional styrenic monomers such as divinylbenzene; diallyl phthalate, diallyl isophthalate, triallyl cyanurate, Polyfunctional allyl ester monomers such as triallyl isocyanurate; 2- (2-vinyloxyethoxy) ethyl (meth) acrylate; urethane acrylate oligomer (for example, Shigemi (registered trademark) series (Nippon Synthetic Chemical Industry Co., Ltd.) Manufactured), CN series (manufactured by Sartomer), Unidic (registered trademark) series (manufactured by DIC Corporation), KAYARAD (registered trademark) UX series (manufactured by Nippon Kayaku Co., Ltd.), and the like).
R ^z1 —O— (R ^z2 —O—) _n ^-unit (R ^z1 represents a (meth) acryloyl group. R ^z2 represents an ethylene group or a propylene group. N represents an integer. .) Is R ^z1- (O) _tz -L ^z _-unit (tz represents an integer of 0 or 1, L ^z is a single bond, and is represented by any one of formulas (a1) to (a3) described later. Or a combination of two or more of the linking groups represented by the formulas (a1) to (a3) described later), and R ^z1 —O— (CH ₂ CH ₂ —O—) _nz unit (nz represents an integer of 1 to 30) is preferable.

  When the dispersion medium is different from the solvent used in the preparation of the hydrothermal reaction or the mixed solution (reaction solvent), the reaction solvent may be replaced with the dispersion medium by solvent exchange. For example, the solvent can be exchanged by mixing a mixed liquid containing inorganic particles, coated inorganic particles and a reaction solvent, and a dispersion medium, and removing the reaction solvent under reduced pressure or the like.

  The inorganic particle dispersion of the present invention further includes an organic phosphorus compound or a salt thereof (hereinafter sometimes simply referred to as “organic phosphorus compound”) and / or an organic sulfur compound or a salt thereof (hereinafter simply referred to as “organic sulfur compound”). In some cases). The hydroxyl group contained in the organic phosphorus compound and / or the organic sulfur compound is considered to improve the dispersibility in the inorganic particle dispersion by improving the dispersibility of the particles and the storage stability of the dispersion containing the particles. By using an organophosphorus compound and / or an organosulfur compound, it becomes easier to disperse at a high concentration, and the thixotropy is easily improved.

  The organic phosphorus compound means a phosphoric acid compound, a phosphorous acid compound, a phosphonic acid compound, or an ester thereof, and a compound having a hydrocarbon group or an organic functional group. Since stability can be improved more, phosphate ester is preferable. The organophosphorus compound is preferably a compound represented by the formula (1).

［式（１）中、Ｒ¹は、炭素数１〜５０の飽和又は不飽和炭化水素基、（メタ）アクリロイル基又は炭素数６〜１００の芳香族含有炭化水素基を表す。
ａ及びｂは、それぞれ１又は２の整数を表し、ａ及びｂの合計は３である。ｃは、０又は１の整数を表す。ｔ１は０又は１の整数を表す。
Ｌ¹は、単結合、式（ａ１）〜式（ａ３）のいずれかで表される連結基又は式（ａ１）〜式（ａ３）で表される連結基のうち２以上を組み合わせた連結基を表し、式（ａ１）〜（ａ３）で表される連結基のいずれかを含む場合、式（ａ１）〜（ａ３）で表される連結基の酸素原子側でリン原子と結合する。

（式（ａ１）〜（ａ３）中、Ｒ²〜Ｒ⁴は、炭素数１〜１８の飽和又は不飽和炭化水素基又は炭素数６〜３０の芳香族含有炭化水素基を表し、Ｒ²〜Ｒ⁴を構成する水素原子は、エーテル基で置換されていてもよい。
ｐ１、ｑ１及びｒ１は、それぞれ１〜２００の整数を表し、ｐ１、ｑ１及びｒ１の合計は１〜２００である。）］

[Equation (1), R ¹ represents a saturated or unsaturated hydrocarbon group having 1 to 50 carbon atoms, a (meth) acryloyl group or an aromatic-containing hydrocarbon group having a carbon number of 6 to 100.
a and b each represent an integer of 1 or 2, and the sum of a and b is 3. c represents an integer of 0 or 1. t1 represents an integer of 0 or 1.
L ¹ is a single bond, a linking group represented by any one of formulas (a1) to (a3), or a linking group in which two or more of the linking groups represented by formulas (a1) to (a3) are combined. In the case where any one of the linking groups represented by formulas (a1) to (a3) is included, it is bonded to the phosphorus atom on the oxygen atom side of the linking groups represented by formulas (a1) to (a3).

(In the formulas (a1) to (a3), R ^{2 to} R ⁴ represent a saturated or unsaturated hydrocarbon group having 1 to 18 carbon atoms or an aromatic-containing hydrocarbon group having 6 to 30 carbon atoms, and R ² to The hydrogen atom constituting R ⁴ may be substituted with an ether group.
p1, q1 and r1 each represent an integer of 1 to 200, and the total of p1, q1 and r1 is 1 to 200. ]]

  In the formula (1), the connecting order of the linking groups represented by the formulas (a1) to (a3) is not particularly limited, and may have a block structure in which the same unit repeats, and a plurality of different units may be disordered. The bond may have a random structure and may have another linking group.

  As a compound represented by Formula (1), the compound represented by either of Formula (1-1)-Formula (1-3) is mentioned, The compound represented by Formula (1-1) is preferable. .

［式（１−１）〜（１−３）中、Ｒ¹、Ｌ¹、ａ、ｂ、ｔ１は上記と同義である］

[In the formulas (1-1) to (1-3), R ¹ , L ¹ , a, b, and t1 are as defined above.

The saturated or unsaturated hydrocarbon group represented by R ¹ includes methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group. Straight chain or branched alkyl group such as vinyl group, tridecyl group and stearyl group; straight chain such as vinyl group, propenyl group, butenyl group, pentenyl group, nonenyl group, decenyl group, hexadecenyl group, octadecenyl group and octadecadienyl group Or a branched alkenyl group; more preferably a linear or branched alkyl group having 1 to 10 carbon atoms or a linear or branched alkenyl group having 2 to 4 carbon atoms, particularly preferably a methyl group, Ethyl group, propyl group (n-propyl group, iso-propyl group, etc.), butyl group (n-butyl group, tert-butyl group, sec-butyl) Group), octyl group (n-octyl group, methylheptyl group, dimethylhexyl group, 2-ethylhexyl group, 3-ethylhexyl group, etc.), decyl group, vinyl group, propenyl group (2-methylallyl group, 2-methylallyl group) And the like, most preferably a methyl group, an ethyl group, an octyl group, a decyl group, or a 1-methylvinyl group.

  Carbon number of a saturated or unsaturated hydrocarbon group becomes like this. Preferably it is 1-25, More preferably, it is 1-18, More preferably, it is 1-12. The carbon number of the saturated hydrocarbon group is preferably 1 to 25, more preferably 1 to 18, further preferably 1 to 12, particularly preferably 1 to 10, and the carbon number of the unsaturated hydrocarbon group is preferably It is 2-25, More preferably, it is 2-18, More preferably, it is 2-12, Most preferably, it is 2-4.

The hydrogen atom of the saturated or unsaturated hydrocarbon group represented by R ¹ may be substituted with an aromatic-containing hydrocarbon group having 6 to 100 carbon atoms. The aromatic-containing hydrocarbon group is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. Examples of the saturated or unsaturated hydrocarbon group substituted with the aromatic-containing hydrocarbon group include the following groups (* indicates a bonding site with an adjacent oxygen atom).

Aromatic-containing hydrocarbon group as the substituent of the saturated or unsaturated hydrocarbon group represented by aromatic-containing hydrocarbon group or R ¹ represented by R ^1, 1-5 ring (more preferably 1 to 3 Ring), and in the case of two or more rings, they may be condensed. In the case of two or more rings, at least one ring is an aromatic ring. When there are two or more aromatic rings, these may be condensed or may be directly bonded by sigma bonds.
Examples of the aromatic-containing hydrocarbon group include a phenyl group, a naphthyl group, a pentarenyl group, an indenyl group, an anthracenyl group, a phenanthryl group, a fluorenyl group, a biphenylyl group, and the like, preferably a phenyl group or a naphthyl group, more preferably It is a phenyl group.
The hydrogen atom of the aromatic-containing hydrocarbon group (such as an aryl group) may be substituted with an alkyl group having 1 to 50 carbon atoms, an alkenyl group having 1 to 50 carbon atoms, or an aralkyl group having 7 to 50 carbon atoms. .

Examples of the alkyl group having 1 to 50 carbon atoms include linear or branched alkyl groups, preferably an alkyl group having 1 to 25 carbon atoms; more preferably an alkyl group having 5 to 15 carbon atoms; and particularly preferably nonyl. Group, decyl group, isodecyl group, undecyl group and dodecyl group.
Examples of the alkenyl group having 1 to 50 carbon atoms include linear or branched alkenyl groups, preferably linear or branched alkenyl groups having 2 to 4 carbon atoms; more preferably vinyl groups and propenyl groups (allyl groups). 1-methylvinyl group, etc.) and butenyl group (1-butenyl group, 2-butenyl group, 3-butenyl group, 1-methylallyl group, 2-methylallyl group, etc.).
Examples of the aralkyl group having 7 to 50 carbon atoms include benzyl group, phenylethyl group, phenylpropyl group, phenylbutyl group, and phenylpentyl group, preferably benzyl group and phenylethyl group; more preferably phenylethyl group. More preferably a 1-phenylethyl group.
Examples of the aromatic-containing hydrocarbon group having an alkyl group having 1 to 50 carbon atoms, an alkenyl group having 1 to 50 carbon atoms, and an aralkyl group having 7 to 50 carbon atoms include groups included in the following group A.

[Group A]

p1, q1, and r1 are each a molar ratio with respect to 1 mole of R ^1- (O) _t1 -L ¹ -unit, and each is 1 to 200, preferably 1 to 100, more preferably 1 to 50, Preferably it is 1-30. The sum total of p1, q1 and r1 is 1 to 200, preferably 1 to 100, more preferably 1 to 50, and still more preferably 1 to 30. t1 is preferably 1.

The divalent hydrocarbon group having 1 to 18 carbon atoms represented by R ^{2 to} R ⁴ may be a saturated or unsaturated hydrocarbon group, and is preferably a saturated hydrocarbon group. Examples of the divalent hydrocarbon group include methylene group, ethylene group, propylene group, butylene group, pentylene group, cyclopentylene group, hexylene group, cyclohexylene group, heptylene group, octylene group, nonylene group, decylene group, undecylene group. Group, dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene group, octadecylene group, isooctadeylene group and other linear, branched or ring structure-containing alkylene groups, preferably methylene group, An ethylene group, an n-propylene group, an iso-propylene group, an n-butylene group, a tert-butylene group and a sec-butylene group, more preferably an ethylene group and an iso-propylene group. The divalent hydrocarbon group preferably has 1 to 8 carbon atoms.

The hydrogen atom of the divalent hydrocarbon group represented by R ^{2 to} R ⁴ may be substituted with an aromatic hydrocarbon group having 6 to 100 carbon atoms. Examples of the aromatic-containing hydrocarbon group include the same groups as those exemplified as the aromatic hydrocarbon group represented by R ¹ , preferably a phenyl group or a naphthyl group, more preferably a phenyl group. . The hydrocarbon group substituted with an aromatic-containing hydrocarbon group is preferably a 1-phenylethane-1,2-diyl group.

The divalent aromatic-containing hydrocarbon group having 6 to 30 carbon atoms represented by R ^{2 to} R ⁴ preferably has 1 to 5 rings (more preferably 1 to 3 rings). May be condensed. Examples of the divalent aromatic-containing hydrocarbon group include phenylene group, naphthylene group, pentalenylene group, indenylene group, anthracenylene group, phenanthrylene group, fluorenylene group, biphenylylene group and the like.
The hydrogen atom of the aromatic-containing hydrocarbon group may be substituted with an alkyl group having 1 to 18 carbon atoms. Examples of the alkyl group include groups having 1 to 18 carbon atoms among the alkyl groups exemplified as the saturated or unsaturated hydrocarbon group represented by R ¹ . Carbon number of this aromatic containing hydrocarbon group becomes like this. Preferably it is 6-18, More preferably, it is 6-8.

The hydrogen atoms constituting R ^{2 to} R ⁴ may be substituted with an ether group. As the ether group, -O- was bonded to the bonding site of a (meth) acryloyl group; a saturated or unsaturated hydrocarbon group having 1 to 50 carbon atoms, or an aromatic hydrocarbon group having 6 to 100 carbon atoms. Groups and the like. Examples of the saturated or unsaturated hydrocarbon group and aromatic hydrocarbon group include the same groups as the saturated or unsaturated hydrocarbon group and aromatic hydrocarbon group represented by R ¹ . The ether group is preferably a group in which —O— is bonded to a saturated or unsaturated hydrocarbon group, and more preferably * —O—C _n H _2n-1 (where n is an integer of 1 to 18). preferable.

  The linking group represented by the formula (a1) preferably includes at least one linking group represented by the following formula (wherein p11 to p15 have the same meaning as p1).

  The linking group represented by the formula (a2) preferably includes at least one linking group represented by the following formula (wherein q11 to q14 have the same meaning as q1).

  The linking group represented by the formula (a3) preferably includes at least one linking group represented by the following formula (wherein r11 to r12 have the same meaning as r1).

  p11 to p15, q11 to q14, and r11 to r12 are each preferably 1 to 200, more preferably 1 to 100, still more preferably 1 to 50, and still more preferably 1 to 30.

L ¹ preferably includes a linking group represented by the formula (a1), and particularly includes one or both of the linking groups represented by the formula (a1-1) and the formula (a1-2). preferable. In this case, the total of p11 and p12 is preferably 1 to 200, more preferably 1 to 100, still more preferably 1 to 50, and most preferably 1 to 30.

  Examples of the organic phosphorus compound include Newcol 1000-FCP (manufactured by Nippon Emulsifier Co., Ltd.), Antox EHD-400 (manufactured by Nippon Emulsifier Co., Ltd.), Phoslex series (manufactured by SC Organic Chemical Co., Ltd.), and light acrylate P-1A (Kyoeisha Chemical Co., Ltd.). Light acrylate P-1M (manufactured by Kyoeisha Chemical Co., Ltd.), TEGO (registered trademark) Dispers 651, 655, 656 (manufactured by Evonik), DISPERBYK-110, 111, 180 (manufactured by Big Chemie Japan), KAYAMERPM-2 KAYAMERPM-21 (manufactured by Nippon Kayaku Co., Ltd.) or the like can be used.

  Examples of the organic phosphorus compound include compounds represented by the following formula. In the formula, a is 1 or 2, and is preferably 1. p11, p12, r1, and r12 are as defined above.

  In the above formula, p11, p12, and p15 may be 4 to 15. The total of p11, p12 and p15 is preferably 1 to 100, more preferably 1 to 50, still more preferably 1 to 30. r1 and r12 are particularly preferably 1 to 20.

  In the present invention, two or more organic phosphorus compounds having different structures such as phosphoric acid monoester and phosphoric acid diester or salts thereof may be used alone or in combination.

  The organic sulfur compound is a sulfonic acid compound which may have a substituent, and is preferably a compound represented by the formula (2).

［式（２）中、Ｒ⁵は、炭素数１〜５０の飽和若しくは不飽和炭化水素基、（メタ）アクリロイル基又は炭素数６〜１００の芳香族含有炭化水素基を表す。
ｔ２は、０又は１の整数を表す。
Ｌ²は、単結合、式（ｂ１）〜（ｂ３）で表される連結基又は式（ｂ１）〜（ｂ３）で表される連結基の２以上を組み合わせた連結基を表し、式（ｂ１）〜（ｂ３）で表される連結基のいずれかを含む場合、式（ｂ１）〜（ｂ３）で表される連結基の酸素原子側で硫黄原子と結合する。

（式（ｂ１）〜（ｂ３）中、Ｒ⁶〜Ｒ⁸は、炭素数１〜１８の炭化水素基又は炭素数６〜３０の芳香族含有炭化水素基を表し、Ｒ⁶〜Ｒ⁸を構成する水素原子は、エーテル基で置換されていてもよい。
ｐ２、ｑ２及びｒ２は、それぞれ１〜２００であり、ｐ２、ｑ２及びｒ２の合計は１〜２００である。）］

Wherein (2), R ⁵ represents represents a saturated or unsaturated hydrocarbon group having 1 to 50 carbon atoms, a (meth) acryloyl group or an aromatic-containing hydrocarbon group having a carbon number of 6 to 100.
t2 represents an integer of 0 or 1.
L ² represents a single bond, a linking group represented by formulas (b1) to (b3), or a linking group obtained by combining two or more of the linking groups represented by formulas (b1) to (b3). ) To (b3), any of the linking groups represented by (b3) is bonded to a sulfur atom on the oxygen atom side of the linking groups represented by the formulas (b1) to (b3).

(In the formulas (b1) to (b3), R ^{6 to} R ⁸ represent a hydrocarbon group having 1 to 18 carbon atoms or an aromatic hydrocarbon group having 6 to 30 carbon atoms, and constitute R ^{6 to} R ⁸ . The hydrogen atom to be substituted may be substituted with an ether group.
p2, q2 and r2 are each 1 to 200, and the sum of p2, q2 and r2 is 1 to 200. ]]

In the formula (b1), as the saturated or unsaturated hydrocarbon group represented by R ⁵ , the (meth) acryloyl group or the aromatic-containing hydrocarbon group, a saturated or unsaturated hydrocarbon group represented by R ¹ , ( It can be selected from the same as the (meth) acryloyl group and the aromatic-containing hydrocarbon group. The hydrogen atom of the saturated or unsaturated hydrocarbon group represented by R ⁵ may be substituted with an aromatic-containing hydrocarbon group having 6 to 100 carbon atoms, and the aromatic-containing hydrocarbon group represented by R ⁵ The hydrogen atom may be substituted with a substituent such as an alkyl group having 1 to 50 carbon atoms, an alkenyl group having 1 to 50 carbon atoms, or an aralkyl group having 7 to 50 carbon atoms. As these alkyl groups having 1 to 50 carbon atoms, alkenyl groups having 1 to 50 carbon atoms, and aralkyl groups having 7 to 50 carbon atoms, hydrogen atoms contained in the aromatic-containing hydrocarbon group represented by R ¹ are substituted. Examples thereof may include the same groups as those exemplified as the alkyl group having 1 to 50 carbon atoms, the alkenyl group having 1 to 50 carbon atoms, and the aralkyl group having 7 to 50 carbon atoms.

R ⁵ is a linear or branched alkyl group having 1 to 50 carbon atoms, a linear or branched alkenyl group having 2 to 50 carbon atoms, a (meth) acryloyl group, or an aromatic hydrocarbon containing 6 to 20 carbon atoms. Group is preferable, a linear or branched alkyl group having 1 to 30 carbon atoms, a linear or branched alkenyl group having 2 to 30 carbon atoms, or an aromatic-containing hydrocarbon group having 6 to 20 carbon atoms is more preferable. A linear or branched alkyl group having 1 to 25 carbon atoms, a linear or branched alkenyl group having 2 to 25 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms is more preferable, and a vinyl group or a propenyl group ( An allyl group, 1-methylvinyl group, etc.), a butenyl group (1-methylallyl group, 2-methylallyl group, etc.) and a phenyl group which may have a substituent are even more preferable, vinyl group, propenyl group, butenyl. And groups included in the group A is particularly preferred.

p2, q2 and r2 are each a molar ratio with respect to 1 mol of R ^5- (O) _t2 -L ² -units, and each is 1 to 200, preferably 1 to 50. t2 is preferably 0. R ⁶ , R ⁷ and R ⁸ preferably have the same structure as R ² , R ³ and R ⁴ .

The R ⁵ — (O) _t2 —L ² — unit preferably contains either or both of the linking groups represented by the above formula (a1-1) and formula (a1-2). In this case, p11 and p12 are each preferably 1 to 200, more preferably 1 to 100, still more preferably 1 to 50, and particularly preferably 1 to 30. The total of p11 and p12 is preferably 1 to 200, more preferably 1 to 100, still more preferably 1 to 50, and particularly preferably 1 to 30.

  Examples of the organic sulfur compound include benzenesulfonic acid, dodecylbenzenesulfonic acid, methylsulfonic acid, ethylsulfonic acid, and various organic sulfur compounds represented by the following formulas (wherein p11 is as defined above). And R represents an optional substituent.

  The organic phosphorus compound and / or the organic sulfur compound may be a salt. Examples of the salt include alkali metal salts such as sodium salt and potassium salt; alkaline earth metal salts such as calcium salt; quaternary ammonium Salt; and the like.

  The total content of the organic phosphorus compound and / or organic sulfur compound is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, and still more preferably 0.7% in 100% by mass of the dispersion. ˜3 mass%. Within the above range, it is easy to improve storage stability and monomer compatibility while maintaining the refractive index.

  The content of the organic phosphorus compound and / or organic sulfur compound is preferably 30% by mass or less with respect to 100% by mass of the inorganic particles, and in optical applications, it is preferably 0.05 to 20% by mass, More preferably, it is 0.5-10 mass%, More preferably, it is 1-5 mass%. If the content of the organophosphorus compound and / or the organosulfur compound is within the above range, excellent storage stability can be exhibited without aggregating the metal oxide particles.

  When the inorganic particle dispersion contains an organic phosphorus compound and / or organic sulfur compound, the timing of addition to the dispersion is, for example, (i) dried inorganic particles, dispersion medium, and organic phosphorus compound and / or organic sulfur compound. Or (ii) a solution in which inorganic particles are dispersed in a dispersion medium in advance, and an organic phosphorus compound and / or organic sulfur compound are brought into contact with each other. Examples thereof include a method of adding a phosphorus compound and / or an organic sulfur compound.

  The temperature at which the organic phosphorus compound and / or organic sulfur compound is added to the dispersion is not particularly limited, and is preferably about 0 to 80 ° C, more preferably about 20 to 60 ° C. Moreover, the pressure at the time of adding an organophosphorus compound and / or an organosulfur compound to a dispersion is not specifically limited, The normal pressure of about 0.9-1.1 atm is preferable.

The inorganic particle dispersion of the present invention may further contain a polymer (resin). Hereinafter, an inorganic particle dispersion containing a polymer (resin) may be referred to as a resin composition. The resin composition may contain a polymer (resin) and a monomer.
As said polymer (resin), 1 type (s) or 2 or more types can be used, for example, polyamides, such as 6-nylon, 66-nylon, and 12-nylon; Polyimides; Polyurethanes; Polyolefins, such as polyethylene and polypropylene Polyesters such as PET, PBT, PEN; Polyvinyl chlorides; Polyvinylidene chlorides; Polyvinyl acetates; Polystyrenes; (Meth) acrylic resin-based polymers; ABS resins; Fluorine resins; Phenol / formalin resins; -Phenolic resins such as formalin resins; epoxy resins; urea resins; melamine resins; amino resins such as guanamine resins; polyvinyl butyral resins; polyurethane resins; ethylene-vinyl acetate copolymer resins; ethylene- (meth) acrylic esters Copolymer Soft resin and hard resin such as a resin; and the like. Among the above, polyimides, polyurethanes, polyesters, (meth) acrylic resin polymers, phenol resins, amino resins, and epoxy resins are more preferable.

  In addition, the inorganic particle dispersion of the present invention includes a surfactant, a curing agent, a curing accelerator, a colorant, an internal mold release agent, a coupling agent, a reactive diluent, as long as the effects of the present invention are not impaired. Other additions such as plasticizers, stabilizers, flame retardant aids, crosslinking agents, low shrinkage agents, polymerization inhibitors, antioxidants, UV absorbers, antifoaming agents, leveling agents, thixotropic agents, thickeners, etc. Ingredients may be included. The content of these additive components is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and further preferably 0 to 3 parts by mass with respect to 100 parts by mass in total of the inorganic particles and the dispersion medium.

  Furthermore, the inorganic particle dispersion of the present invention may contain additional components other than those described above. The content of additional components other than the above is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, still more preferably 1 part by mass or less, particularly preferably 100 parts by mass in total of the inorganic particles and the dispersion medium. 0 parts by mass.

<Preferred use>
The inorganic particle dispersion of the present invention can be developed for various uses represented by articles or the like obtained by molding or curing the dispersion. Examples include resist applications, optical applications, coating applications, and adhesive applications. Optical lenses, optical film adhesives, optical film adhesives, nanoimprint resin compositions, microlens arrays, and antireflection layers used for transparent electrodes , Antireflection film and antireflection agent, surface coating of optical lens, organic EL light extraction layer, various hard coating materials, flattening film for TFT, overcoat for color filter, various protective films such as antireflection film, and optical filter It is suitably used for optical materials such as insulating films for touch sensors, insulating films for TFTs, photo spacers for color filters, and protective films for touch panels. In particular, the coated metal oxide particles of the present invention have high refractive index, high hardness, and high stability in addition to remarkable dispersibility, so that they are optical lenses, optical lens surface coats, various hard coat materials, and insulation for touch sensors. It is preferably used for a film, an insulating film for TFT, and a protective film for touch panel.

  Furthermore, the coated metal oxide particles of the present invention can be applied to semiconductor gate insulating films and memory capacitor insulating films such as DRAMs by making use of their high dielectric constants in addition to optical applications. As a method for obtaining such an insulating film having a high dielectric constant, a method in which an organic metal precursor is used and an oxidation process is performed after vapor deposition such as CVD (Chemical Vapor Deposition) or ALD (Atomic Layer Deposition). It has been known. In order to obtain a metal oxide having a desired high dielectric constant, a high temperature treatment of 600 ° C. or higher is required. However, due to the influence, a phenomenon that causes unstable operation of the semiconductor layer such as a pinning phenomenon occurs. The coated metal oxide particles of the present invention do not require high-temperature treatment, have already a high dielectric constant at the time of production, and are single particles of several nanometers, so that they can be stacked to accommodate future semiconductor miniaturization At the same time, since it does not require high-temperature treatment, it can be applied to semiconductor manufacturing on a plastic substrate.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples, but may be implemented with appropriate modifications within a range that can meet the purpose described above and below. Of course, any of these is also included in the technical scope of the present invention.
In the following, “part” means “part by mass” and “%” means “mass%” unless otherwise specified.

The physical properties and characteristics disclosed in the examples were measured by the following methods.
(1) Viscosity change rate As an inorganic particle dispersion, what was allowed to stand for 24 hours in an air atmosphere at 25 ° C. was used. The shear viscosity at 1 s ⁻¹ and 100 s ⁻¹ of the inorganic particle dispersion was measured using a rheometer (ARES-G2 manufactured by TA Instruments). At that time, the cone plate was rotated in a state where the gap between the conical portion of the cone plate and the measurement portion was filled with the inorganic particle dispersion. Depending on the viscosity of the inorganic particle dispersion,
A "Diameter 25mm, cone angle 0.1 rad"
B "Diameter 25mm, cone angle 0.02 rad"
C "diameter 50mm, cone angle 0.02 rad"
The three types were selected and measured. The temperature of the measurement part was adjusted to 25 ° C., the shear rate was measured at a constant value of 1 s ⁻¹ or 100 s ⁻¹ , and the value 5 minutes after the start was taken as the shear viscosity.
Viscosity change rate was calculated based on the following formula, and 2.0 or more was evaluated as ○, and less than 2.0 was evaluated as ×.
Viscosity change rate = (shear viscosity at a liquid temperature of 25 ° C. at a shear rate of 1 s ⁻¹ ) / (shear viscosity at a liquid temperature of 25 ° C. at a shear rate of 100 s ⁻¹ )

(2) Total light transmittance The total light transmittance of the inorganic particle dispersion was measured using a turbidimeter (NDH7000 manufactured by Nippon Denshoku Industries Co., Ltd.). The cell used was a quartz cell with an optical path length of 1 cm.
The total light transmittance of 50% or more was evaluated as ◯, and the evaluation of less than 50% was evaluated as ×.

(3) Fluidity 45 mL of the inorganic particle dispersion was poured into a test tube having an outer diameter of 30 mm, and left in a 25 ° C. atmosphere for 24 hours in a vertical state. If necessary, the sample was heated until the minimum fluidity required to pour the sample into the test tube was obtained. Subsequently, after confirming that the sample was adjusted to a temperature of 25 ° C., the sample was kept horizontal for 5 seconds and observed. The case where the sample moved was evaluated as ◯, and the case where the sample did not move was evaluated as X.

(4) Measurement of mass reduction rate Using a TG-DTA (thermogravimetric-differential thermal analysis) device, the temperature of the coated zirconium oxide particles was increased from room temperature to 800 ° C at 10 ° C / min in an air atmosphere, and the mass of the particles The reduction rate was measured. From this mass reduction rate, the ratio of the carboxylate compound covering the metal oxide particles and the ratio of the metal oxide can be known.

Production Example 1
Production of coated zirconium oxide nanoparticles coated with 2-ethylhexanoic acid and / or 2-ethylhexanoic acid-derived carboxylate (coated ZrO ₂ particles 1) 2-ethylhexanoic acid zirconium mineral spirit solution (782 g, 2 -Pure water (268 g) was mixed with zirconium ethylhexanoate content of 44% by mass, manufactured by Daiichi Elemental Chemical Co., Ltd. The obtained mixed solution was charged into an autoclave equipped with a stirrer, and the atmosphere in the autoclave was replaced with nitrogen gas. Thereafter, the mixed solution was heated to 180 ° C. and kept at that temperature for 16 hours (the pressure in the autoclave was 0.94 MPa) to cause reaction, thereby producing zirconium oxide particles. Subsequently, the mixed solution after the reaction was taken out, the precipitate accumulated at the bottom was filtered off, washed with acetone, and dried. When the precipitate (100 g) after drying was dispersed in toluene (800 mL), a cloudy solution was obtained. Next, as a purification step, filtration was performed again with a quantitative filter paper (No. 5C, manufactured by Advantech Toyo Co., Ltd.) to remove coarse particles and the like in the precipitate. Further, the filtrate was concentrated under reduced pressure to remove toluene, whereby white zirconium oxide nanoparticles (coated ZrO ₂ particles 1) were recovered.

When the crystal structure of the obtained coated ZrO ₂ particles 1 was confirmed, diffraction lines belonging to tetragonal crystals and monoclinic crystals were detected. From the intensity of the diffraction lines, the ratio of tetragonal crystals to monoclinic crystals was 54 / No. 46, and the particle diameter (crystallite diameter) was 5 nm.
The average particle diameter (number-based average primary particle diameter) of the coated ZrO ₂ particles 1 obtained by measurement with an electron microscope was 12 nm. Further, when the obtained coated ZrO ₂ particles 1 were analyzed by infrared absorption spectrum, absorption derived from C—H and absorption derived from COOH could be confirmed. This absorption is considered to be caused by 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid coated on the coated ZrO ₂ particles 1.
Furthermore, the mass reduction rate of the coated ZrO ₂ particles 1 measured according to the above-mentioned “(4) Measurement of mass reduction rate” was 12% by mass. Therefore, coating type ZrO ₂ 2-ethylhexanoic acid particles 1 coated and / or 2-ethylhexanoic acid from the carboxylate, it was found to be 12% by weight of the total coating type ZrO ₂ particles 1.

Production Example 2
Zirconium oxide nanoparticles coated with 2-ethylhexanoic acid and / or 2-ethylhexanoic acid-derived carboxylate, 2-acryloyloxyethyl succinate and 3-methacryloxypropyltrimethoxysilane (coated ZrO ₂ particles 2) The coated ZrO ₂ particles 1 (10 g) obtained in Production Example 1 were dispersed in methyl isobutyl ketone (40 g) to prepare a cloudy slurry. Add 3-methacryloxypropyltrimethoxysilane (2.0 g, manufactured by Shin-Etsu Chemical Co., Ltd., KBM-503) and water (0.9 g) as a surface treatment agent to the solution, and heat to reflux at 80 ° C. for 1 hour. A transparent dispersion solution was obtained. Next, the temperature was lowered to 50 ° C., and then 2-acryloyloxyethyl succinate (1.8 g) was added and mixed with stirring for 30 minutes to obtain a zirconium oxide dispersion.

Next, n-hexane was added to agglomerate the dispersed particles to make the solution cloudy. Aggregated particles are separated from the white turbid solution with a filter paper and dried by heating at room temperature. 2-ethylhexanoic acid and / or 2-ethylhexanoic acid-derived carboxylate, 2-acryloyloxyethyl succinate, and 3-methacryloxypropyltrimethoxy Zirconium oxide nanoparticles coated with silane (coated ZrO ₂ particles 2) were prepared.

The mass reduction rate of the coated ZrO ₂ particles 2 measured according to “(4) Measurement of mass reduction rate” was 17% by mass. This confirmed that the organic content of the coated ZrO ₂ particles 2 was 17% by mass.
Further, the coating-type ZrO ₂ grains 2 was analyzed by a fluorescent X-ray analyzer, Zr, by measuring the Si content of 3-methacryloxypropyl trimethoxysilane weight-coated ZrO ₂ particles 2 to 8 wt% I found out that
The obtained coated ZrO ₂ particles 2 were dispersed in deuterated chloroform to obtain a measurement sample, and analyzed by ¹ H-NMR. As a result, the molar ratio of 2-ethylhexanoic acid and / or 2-ethylhexanoic acid-derived carboxylate, 3-methacryloxypropyltrimethoxysilane, and 2-acryloyloxyethyl succinate is 27:35:38. I understood.

In consideration of the above-mentioned analysis results by TG-DTA, X-ray fluorescence analysis, and ¹ H-NMR, carboxylate derived from 2-ethylhexanoic acid and / or 2-ethylhexanoic acid, 3-methacryloxypropyltrimethoxysilane and 2 -Acryloyloxyethyl succinate was found to be 3%, 8% and 7% by weight, respectively, of the entire coated ZrO ₂ particle 2 (100% by weight).

Production Example 3
The coated ZrO ₂ particles 2 obtained in Production Example 2 (7 g), methyl ethyl ketone (3 g), Antox EHD-400 (manufactured by Nippon Emulsifier Co., Ltd., 0.14 g) are blended and stirred uniformly to disperse the zirconium oxide. A liquid was obtained.

Example 1
70 g of the zirconium oxide dispersion obtained in Production Example 3 (a methyl ethyl ketone dispersion having a number average primary particle diameter of 11 nm of zirconium oxide and a particle content of 70%), and 12.3 g of ethoxylated o-phenylphenol acrylate as a dispersion medium (Shin Nakamura) After blending NK ester A-LEN-10) manufactured by Chemical Industry Co., Ltd. and stirring uniformly, methyl ethyl ketone was removed under reduced pressure using a rotary evaporator to obtain an inorganic particle dispersion. The evaluation results are shown in Table 1. Cone plate B was used for measuring the shear viscosity.

Examples 2-3 and Comparative Examples 1-3
An inorganic particle dispersion was obtained in the same manner as in Example 1 except that 12.3 g of ethoxylated o-phenylphenol acrylate was changed as shown in Table 1. The evaluation results are shown in Table 1. When measuring the shear viscosity, cone plate B was used in Example 2, cone plate A was used in Example 3, and cone plate C was used in Comparative Examples 1-3.

Claims (6)

Including inorganic particles and dispersion medium,
The total light transmittance is 50% or more,
The content of the inorganic particles is 60% by mass or more,
A dispersion in which the viscosity of the dispersion medium at a temperature of 25 ° C. is 6 mPa · s or more and a viscosity change rate represented by the following formula is 2.0 or more.
Viscosity change rate = (shear viscosity at a liquid temperature of 25 ° C. at a shear rate of 1 s ⁻¹ ) / (shear viscosity at a liquid temperature of 25 ° C. at a shear rate of 100 s ⁻¹ )   The dispersion according to claim 1, wherein the number average primary particle diameter of the inorganic particles is 50 nm or less.   The dispersion according to claim 1, wherein the inorganic particles are metal oxide particles.   The dispersion according to any one of claims 1 to 3, wherein the metal constituting the inorganic particles is at least one selected from Ti, Al, Zr, Zn, Sn, and Ce.   Furthermore, the dispersion in any one of Claims 1-4 containing an organic acid.   Furthermore, the dispersion in any one of Claims 1-5 containing an organic phosphorus compound or its salt, and / or an organic sulfur compound or its salt.