JP2009067949A - Resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition in which zirconium oxide nano-particles are highly dispersed. <P>SOLUTION: The resin composition has zirconium oxide nano-particles coated with a coating agent (I) of a carboxylic acid having ≥6C hydrocarbon group and a coating agent (II), and a curable resin. One kind of the coating agent (II) in the resin composition is preferably an organometallic compound having a metal atom and a hydrolyzable group bonded with the metal atom. The metal atom of the compound is more preferably bonded with a group having an aromatic ring. It is suitable for the zirconium oxide particle to have a relation; (area of aromatic proton peak)/(total proton peak area)×100≥40 in<SP>1</SP>H-NMR analysis. The resin composition more preferably contains a dispersing agent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin composition containing zirconium oxide nanoparticles.

  In recent years, metal oxide nanoparticles have attracted a great deal of attention as contributing to higher functionality and higher performance of various materials such as optical materials, electronic component materials, magnetic recording materials, catalyst materials, and ultraviolet absorbing materials. . For example, when zirconium oxide particles are dispersed in a thermoplastic resin, the refractive index of the resin is improved (see, for example, Patent Document 1).

  A Breaking-down process is known as a method for producing metal oxide particles. A mechanical pulverization method is generally used as a breaking-down process. However, it is difficult to efficiently produce fine particles having a particle size of 1 μm or less by the mechanical pulverization method, and metal oxide particles are used during the pulverization. There is a high possibility that impurities will get inside.

  As another method for producing metal oxide particles, a building-up process is known. The Building-up process is a method of preparing metal oxide particles by a chemical reaction, and is classified into a gas phase method and a liquid phase method. Metal oxide nanoparticles can be prepared by controlling reaction conditions in the process and selecting a raw material. However, since the gas phase method requires special equipment and reaction conditions, there are many problems in terms of cost and safety. Even if a liquid phase method such as a coprecipitation method, an alkoxide method in which metal oxide particles are obtained by hydrolysis of metal alkoxide, or a hydrothermal synthesis method in which a metal oxide precursor is reacted under high temperature and high pressure is adopted, there is a problem. Dots may occur. For example, the coprecipitation method has a problem that the generated metal oxide nanoparticles grow in the heating process. The alkoxide method can be applied only to the production of some metal oxides, and the crystallinity of the resulting metal oxides is not sufficient. In addition, since the hydrothermal synthesis method requires severe conditions such as 400 MPa at 30 MPa, there are problems of coarsening of metal oxide particles and a problem that a large amount of nanoparticles cannot be produced at low cost.

  Incidentally, the metal oxide nanoparticles have a problem of low dispersibility in a resin, an organic solvent having a low polarity, and the like in addition to the above-described problem that the production is difficult.

  Regarding the above-described problem of low dispersibility, a technique in which a compound represented by the following general formula (12) and / or a compound represented by the following general formula (13) is used as a dispersant is disclosed (Patent Document). 2). Although the dispersibility is improved according to the technique, it is desired to further improve the dispersibility.

^{R 12 -R 13 -O- (CO-} R 14 -O) l -CO-R 15 -COOH (12)
In the general formula (12), R ¹² is at least one selected from a hydrogen atom, a halogen atom, an optionally substituted alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an acyl group, and a (meth) acryloyl group. R ¹³ represents an alkylene group, R ¹⁴ represents an alkylene group, R ¹⁵ represents an alkylene group, and 1 is 1 or more.

R ¹⁶ — [CO— (O—R ¹⁷ —CO) _n —OH] _m (13)
In the general formula (13), R ¹⁶ represents an optionally substituted alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, at least one group selected from acyl and (meth) acryloyl group, R ¹⁷ Represents an alkylene group, n represents 1 or more, and m represents 1 to 4.

  In addition, as a technology for improving the dispersibility of other metal oxide nanoparticles, when dispersing zirconium oxide particles in a monomer, a technology for treating the surface of the zirconium oxide particles before the dispersion with a specific metal alkoxide. (See Patent Document 3): When dispersing zirconium oxide particles in a solution in which a polymer is dissolved, a technique for surface modification of the particle surface with both acidic groups and basic groups, or acidic groups (Patent Document) 4)) is disclosed. Even when the surface treatment of metal oxide particles represented by these technologies is performed, the metal oxide nanoparticles before the surface treatment have low dispersibility in the surface treatment agent and further have strong cohesiveness. Therefore, it has been difficult to effectively treat the surface of the metal oxide nanoparticles. That is, it is actually difficult to improve the dispersibility of the metal oxide nanoparticles by surface treatment. Therefore, in order to sufficiently perform the surface treatment of the metal oxide nanoparticles, costly and laborious treatment such as high-temperature and high-pressure treatment (see Patent Document 5) and mill treatment (see Patent Document 6) is necessary.

As a means for solving the problem of dispersibility of the metal oxide nanoparticles, there is a method of imparting high dispersibility to the produced particles in the production process of the metal oxide nanoparticles. For example, a method of producing metal oxide particles containing a carboxylic acid residue by dissolving zinc acetate or the like in alcohol, further adding carboxylic acid and heating (see Patent Document 7); Zr which is an organic phase (IV) —Method of producing zirconium oxide nanoparticles surface-treated with a tertiary carboxylic acid by hydrothermally treating a heterophasic solution of a tertiary carboxylic acid solution and water at around 200 ° C. (Non-patent Document 1) Reference);
JP 2003-73563 A JP 2000-281934 A JP 2005-316219 A JP 2003-73558 A JP 2005-193237 A JP 2005-220264 A JP 2000-185916 A Yasuhiro Konishi et al., The 65th Annual Meeting of the Chemical Engineering Society, Abstracts of Research Presentations, N202 (2000)

  An object of the present invention is to provide a resin composition in which metal oxide nanoparticles, particularly zirconium oxide nanoparticles, are highly dispersed in a curable resin.

  The present inventor has found that zirconium oxide nanoparticles coated with a specific coating agent (I) and a coating agent other than the coating agent (I) (coating agent (II)) are highly dispersed in the curable resin. The present invention has been completed.

That is, the resin composition according to the present invention includes the zirconium oxide nanoparticles coated with the coating agent (I) and the coating agent (II), and a curable resin, and the coating agent (I) is represented by the following general formula: It is a carboxylic acid represented by the formula (1).
R ¹ —COOH (1)
Here, in the general formula (1), R ¹ represents a hydrocarbon group having 6 or more carbon atoms. The coating agent (II) is not limited as long as it is a coating agent other than the coating agent (I).

A preferable example of the coating agent (II) is an organometallic compound having a metal atom and a hydrolyzable group bonded to the metal atom. The organometallic compound is more preferably one in which a group having an aromatic ring is bonded to the metal atom. In this case, the peak area of the ¹ H-NMR chart of the zirconium oxide nanoparticles and the area ratio based on the following formula are preferably 40% or more. The “aromatic proton” refers to a hydrogen atom bonded to carbon forming an aromatic ring.

  When the zirconium oxide nanoparticles contain tetragonal zirconium oxide, the refractive index is high.

  The resin composition of the present invention preferably contains a dispersant. Since the zirconium oxide nanoparticles are coated not only with the coating agent (I) but also with the coating agent (II), the improvement in dispersibility by the dispersant becomes remarkable.

As said dispersing agent, the 1 type, or 2 or more types of compound selected from the compound represented by the following general formula (2)-(4) is preferable.
^{R 2 -R 3 -O- (CO-} R 4 -O) a -CO-R 5 -COOH (2)
(In General Formula (2), R ² represents a group selected from a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an aryl group, an aralkyl group, an acyl group, and a (meth) acryloyl group. R ³ represents an alkylene group or an aryl group, R ⁴ represents an alkylene group, R ⁵ represents a group selected from an alkylene group, an aryl group, and an alkyne group, and a represents an integer of 1 or more. .)
R ⁶ — [CO— (O—R ⁷ —CO) _b —OH] _c (3)
(In General Formula (3), R ⁶ is a hydrogen atom, a halogen atom, an alkyl group that may have a substituent, an aryl group, an aralkyl group, an acyl group, and a vinyl group that may have a substituent. R ⁷ represents an alkylene group, b represents an integer of 1 or more, and c represents an integer of 1 to 4.)
^{R 8 -R 9 -O- (CO-} R 10 -O) d -H (4)
(In the general formula (4), R ⁸ represents a group selected from a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an aryl group, an aralkyl group, an acyl group, and a (meth) acryloyl group. R ⁹ represents an alkylene group or an aryl group, R ¹⁰ represents an alkylene group, and d represents an integer of 1 or more.)

  The curable resin preferably includes an epoxy resin. Moreover, the said resin composition is good in it being a resin composition for optical materials.

  The resin composition can be cured to produce a molded body such as a lens, and an optical component can be produced using the lens.

  According to the resin composition of the present invention, since the zirconium oxide nanoparticles dispersed in the curable resin are coated with the coating agent (I) and the coating agent (II), the dispersibility of the particles is high. As a result, for example, the light transmittance of the cured product of the resin composition is improved.

(Resin composition)
The present invention is described in detail below. The resin composition of the present invention has zirconium oxide nanoparticles (hereinafter, simply referred to as “nanoparticles”) having at least a part of the surface coated with a coating agent, and a curable resin. And the resin composition of this invention may contain the dispersing agent. Moreover, the resin composition of the present invention may contain an additive. Below, the resin composition of this invention is demonstrated in detail.

Nanoparticles As the shape of the nanoparticles, there are a spherical shape, an elliptical spherical shape, a cubic shape, a rectangular parallelepiped shape, a pyramid shape, a needle shape, a columnar shape, a rod shape, a cylindrical shape, a flake shape, a plate shape, a flake shape, etc. The shape of the nanoparticles is spherical and columnar from the viewpoint of dispersibility.

  The particle diameter of the nanoparticles is not particularly limited as long as it can be said to be at the nano level, but the upper limit is usually 20 nm or less. When it exceeds 20 nm, the transparency of the molded body (cured product) of the resin composition tends to decrease. The particle size is preferably 19 nm or less, and more preferably 18 nm or less. On the other hand, the lower limit of the particle diameter is preferably 1 nm or more, and preferably 2 nm or more, which is low in the aggregation property of the nanoparticles. The particle diameter is an average value based on the number of particle diameters measured by microscopic observation. In other words, 100 nano particles selected at random by observing particles with a transmission electron microscope (TEM), a field emission transmission electron microscope (FE-TEM), a field emission scanning electron microscope (FE-SEM), etc. The length in the major axis direction of the particles is measured, and the average value is taken as the particle diameter.

  Since the variation in nanoparticle size may cause variations in the light transmittance and refractive index of the resin composition molded article, it is desirable that the particle size distribution of the nanoparticles be narrow, and the coefficient of variation in the particle diameter ( CV value) is preferably 30% or less, more preferably 25% or less, and even more preferably 20% or less. Here, the coefficient of variation (CV value) is calculated from σ / x × 100 [wherein σ represents a standard deviation of particle size distribution of particles and x represents an average particle size (nm) of particles]. Conversion coefficient.

  Although the minimum of content of the nanoparticle in a resin composition is not specifically limited, Usually, 2 mass%, More preferably, it is 10 mass%. On the other hand, the upper limit is preferably 80% by mass and more preferably 60% by mass as a practical resin composition.

Coating agent In the present invention, in order to enhance the dispersibility of the nanoparticles in the curable resin, the zirconium oxide nanoparticles are not only the coating agent (I) but also the coating agent (II) (other than the coating agent (I). It is also coated with a coating agent). In the following, when both the coating agent (I) and the coating agent (II) are meant, it is referred to as “coating agent”.

The coating agent (I) is a carboxylic acid represented by the following general formula (1), and one or more of them may be selected.
R ¹ —COOH (1)
In general formula (1), R ¹ represents a hydrocarbon group having 6 or more carbon atoms.

  The hydrophilic zirconium oxide surface is generally positively charged, and the carboxyl group in the coating agent (I) exhibits affinity for the zirconium oxide surface, so that the zirconium oxide surface can be coated with the coating agent (I). The carboxyl group in the coating agent (I) may be bonded to the surface of zirconium oxide in the form of —COO—.

Since the carbon number of R ¹ in the coating agent (I) is 6 or more, high dispersibility of nanoparticles in the curable resin can be realized. The coating agent (I) has excellent dispersion of nanoparticles in a hydrophobic solvent such as toluene, xylene, cyclohexane.

R ¹ may be any linear, branched, or cyclic hydrocarbon group. A branched chain rather than a straight chain is preferable because the dispersibility of the nanoparticles in the curable resin and the hydrophobic solvent is particularly excellent.

  Specific examples of the coating agent (I) include linear carboxylic acids such as hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, stearic acid; 2-ethylhexanoic acid, 2- And branched carboxylic acids such as methylheptanoic acid, 4-methyloxanoic acid and neodecanoic acid; and cyclic carboxylic acids such as naphthenic acid and cyclohexanedicarboxylic acid.

From the viewpoint of dispersibility of the nanoparticles, it is preferable to select a branched carboxylic acid such as neodecanoic acid or 2-ethylhexanoic acid as the coating agent (I). In this case, it is more preferable to use the coating agent (I) in which R ¹ is a linear hydrocarbon group, since the dispersibility of the nanoparticles in the curable resin and the hydrophobic solvent can be further improved. It is.

  If the nanoparticles are analyzed with a Fourier transform infrared spectrophotometer (FT-IR), a pyrolysis gas chromatograph mass spectrometer (GC-MS) or the like, it can be confirmed whether the coating agent (I) is coated. For example, if an absorption spectrum derived from COOH is confirmed by FT-IR analysis, the nanoparticles are coated with the coating agent (I).

  One or two or more of the other coating agents (II) may be selected.

  As the coating agent (II), an organic group having a hydrolyzable group such as an alkoxy group, an acyloxy group, a halogen group, or a hydrogen atom and a metal atom such as Si, Al, Ti, or Zr, and these are directly bonded. Metal compounds are preferred. The organometallic compound may have a bonding group such as a phenyl group, an alkyl group, an epoxy group, an amino group, a mercapto group, or a hydroxyl group other than the hydrolyzable group on the metal atom. Such an organometallic compound is also suitable as the coating agent (II). An organometallic compound in which a group having an aromatic ring (for example, an aryl group or an aralkyl group) and a hydrolyzable group are bonded to a metal atom is used as the coating agent ( More suitable as II). And as group which has the said aromatic ring, group (for example, phenyl group) which has a benzene ring is suitable.

  Examples of the organometallic compound corresponding to the coating agent (II) include aluminum trimethoxide, aluminum triethoxide, aluminum triisopropoxide, aluminum tri-n-butoxide, aluminum tri-sec-butoxide, aluminum tri- Aluminum alkoxides such as t-butoxide, monosec-butoxyaluminum diisopropylate, aluminum triethoxyethoxide, aluminum phenoxide; diisopropoxyaluminum ethyl acetoacetate, diisopropoxyaluminum alkyl acetoacetate, diisopropoxyaluminum monomethacrylate, Aluminum stearate oxide trimer, isopropoxy aluminum alkyl acetoacetate mono (dioctyl phosphate) ) And the like; titanium-n-butoxide, titanium tetra-t-butoxide, titanium tetra-sec-butoxide, titanium tetraethoxide, titanium tetraisobutoxide, titanium lactate, titanium tetramethoxide, titanium tetra ( Titanium alkoxides such as methoxypropoxide), titanium tetra (methoxyphenoxide), titanium tetra-n-nonyloxide, titanium tetra-n-butoxide, titanium tetrastearyloxide, titanium bis (triethanolamine) diisopropoxide; Isostearoyl titanate, isopropyl trioctanoyl titanate, tetraoctyl bis (ditridecyl phosphite) titanate, tetraisoprote Pyrbis (dioctyl phosphate) titanate, isopropyl tris (dioctyl pyrophosphate) titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, bis (dioctyl pyrophosphate) ethylene titanate, isopropyl tri (dioctyl phosphate) titanate, isopropyl tri (N-aminoethylaminoethyl) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) phosphite titanate, isopropyldimethacrylisostearoyl titanate, isopropyltridecylbenzenesulfonyl titanate, isopropyltricumylphenyl Titanium coupling agents such as titanate; phenyltrimethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane , Phenyltriethoxysilane, phenyltrichlorosilane, ethoxytriphenylsilane, triphenylchlorosilane, vinyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxy Silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, hexamethyldisilazane, 3-ethyl-3-{[3 Silane coupling agents such as-(triethoxysilyl) propoxy] methyl} oxetane; zirconium tetra n-butoxide, zirconium tetra t-butoxide, zirconium tetra (2-ethylhexoxide), zirconium tetraisobutoxy Zirconium ethoxide such as zirconium tetraethoxide, zirconium tetraisopropoxide, zirconium tetra n-propoxide, zirconium tetra (2-methyl-2-butoxide); zirconium di n-butoxide (bis-2,4-pentanedio ), Zirconium tri-n-butoxide pentadionate, zirconium compounds such as zirconium dimethacrylate dibutoxide, and the like.

  When an organometallic compound is selected as the coating agent (II), analyze the nanoparticles with an inductively coupled plasma analyzer (IPC), electron microanalyzer (XMA), X-ray photoelectron analyzer (ESCA), etc. Thus, it can be confirmed whether the coating agent (II) is coated. That is, if qualitative confirmation of metal elements such as silicon, titanium, and aluminum which are constituent elements of the organometallic compound can be performed, the nanoparticles are coated with the coating agent (II). In addition, if the quantitative analysis of metal elements such as silicon, titanium, and aluminum, which are constituent elements of organometallic compounds by IPC, and zirconium, which is a constituent element of zirconium oxide, is performed, the coating amount of the coating material (II) is confirmed. be able to.

  Moreover, if the absorption spectrum of the group derived from the organometallic compound (for example, -Si-OC-) is confirmed by FT-IR, the nanoparticles are coated with the coating agent (II).

  Coating agents (II) other than the above organometallic compounds include hydroxycarboxylic acids such as hydroxystearic acid and salicylic acid; ether carboxylic acids such as 2- [2- (2-methoxyethoxy) ethoxy] acetic acid; carboxylated polybutadiene and carboxyl A carboxylic acid coupling agent such as conjugated polyisoprene; a carboxylic acid polymer such as maleic acid-modified polypropylene; and an epoxy group such as phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, dibromophenyl glycidyl ether, and N-glycidyl phthalimide. Epoxy compound having one; Oxetane compound having one oxetane group such as 3-ethyl-3 (phenoxymethyl) oxetane; Episulfide having one episulfide group such as epithiopropylphenyl ether Compounds; and the like. The coating agent (II) other than these organometallic compounds preferably has an aromatic ring, and a halogen atom or the like may be bonded to this aromatic ring.

  The ratio of the coating agent (coating agent (I) and coating agent (II)) in the nanoparticles is 40 mass in terms of weight loss when the coated nanoparticles are heated in an air atmosphere to remove organic components. % Or less is preferred. If the weight loss rate exceeds 40% by mass, the amount of the coating agent is too large, and the high refractive effect inherent in zirconium oxide may not be sufficiently exhibited. On the other hand, if the weight loss rate is less than 5% by mass, the amount of the coating agent may be too small and the dispersibility of the particles may not be sufficiently improved. Therefore, the weight loss rate is preferably 5% by mass or more. More preferably, it is 10 mass% or more and 30 mass% or less. More preferably, it is 15 mass% or more and 30 mass% or less. The weight loss rate is calculated by, for example, using a TG-DTA analyzer manufactured by Mac Science Co., Ltd., heating the particles to 800 ° C. at a rate of 10 ° C./min in an air atmosphere, and reducing mass / mass before heating × 100. Value. In addition, the thing whose exothermic peak when measured with a TG-DTA analyzer is 300 degreeC or more is preferable from a viewpoint of the thermal stability of the coated particle | grains.

For the ratio of the coating agent (II) in the coating agent on the nanoparticle surface, for example, an organometallic compound in which a group having a more preferable aromatic ring and a hydrolyzable group are bonded to a metal atom as the coating agent (II) In this case, the peak area of the ¹ H-NMR chart and the area ratio based on the following formula are preferably 40% or more and 99% or less, and more preferably 70% or more. Even if the coating agent (I) has an aromatic ring, the area ratio is preferably 40% or more and 99% or less, and more preferably 70% or more.

Zirconium oxide As the zirconium oxide constituting the nanoparticles is often amorphous, the refractive index of the resin composition molded article is often not sufficiently high. Therefore, any one of cubic, tetragonal and monoclinic crystals is required. It preferably has a crystalline form. Zirconium oxide that exhibits a high refractive index has tetragonal crystals. Therefore, at least a part of the zirconium oxide in the present invention is preferably a tetragonal crystal, and another crystal form such as a monoclinic crystal and / or a cubic crystal may be mixed with the tetragonal crystal.

Dispersant The resin composition according to the present invention preferably contains one or more dispersants in order to improve the dispersibility of the nanoparticles in the resin composition. This nanoparticle dispersibility effect by the dispersant is remarkable because the nanoparticles are coated not only on the coating agent (I) but also on the coating agent (II).

  It is preferable to use one or more selected from compounds represented by the following general formula (2) as a dispersant.

^{R 2 -R 3 -O- (CO-} R 4 -O) a -CO-R 5 -COOH (2)
Details of R ² , R ³ , R ⁴ , R ⁵ , and a in the general formula (2) are as follows. R ² represents a group selected from a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an aryl group, an aralkyl group, an acyl group, and a (meth) acryloyl group. R ³ represents an alkylene group (eg, methylene group, ethylene group, cyclohexylene group) or an aryl group (eg, phenyl group). R ⁴ represents an alkylene group, and the structure thereof is preferably linear rather than cyclic, and the carbon number thereof is preferably 3 to 20 carbon atoms. R ⁵ represents a group selected from an alkylene group, an aryl group, and an alkyne group, preferably an alkylene group, and the structure of the alkylene group is preferably linear rather than cyclic, and the carbon number thereof is It is preferable that it is 2-6. a represents an integer of 1 or more, preferably an integer of 50 or less, and more preferably 20 or less.

  Examples of the compound represented by the general formula (2) include lactone-modified carboxyl group-containing (meth) acrylates such as “Placcel FM1A”, “Placcel FM4A”, and “Placcel FM10A” manufactured by Daicel Chemical Industries, Ltd. And as a specific example of the compound represented by the said General formula (2), the compound represented by following formula (2a)-(2d) is mentioned.

  It is also preferable to use one or more selected from compounds represented by the following general formula (3) as a dispersant. In addition, you may use together 1 type, or 2 or more types of the compound represented by the following general formula (3) with 1 type or 2 or more types of the compound represented by the said General formula (2).

R ⁶ — [CO— (O—R ⁷ —CO) _b —OH] _c (3)
Details of R ⁶ , R ⁷ , b, and c in the general formula (3) are as follows. R ⁶ represents a hydrogen atom, a halogen atom, an alkyl group that may have a substituent, an aryl group, an aralkyl group, an acyl group, and a vinyl group that may have a substituent (for example, a methyl vinyl group). Represents a group selected from R ⁷ represents an alkylene group, and the structure thereof is preferably linear rather than cyclic, and the carbon number thereof is preferably 3 to 20 carbon atoms. b represents an integer of 1 or more, preferably 50 or less, and more preferably 20 or less. c represents an integer of 1 to 4, and is preferably 1 or 2.

  Examples of the compound represented by the general formula (3) include caprolactone-modified products of (meth) acrylic acid such as ω-carboxycaprolactone mono (meth) acrylate and ω-carboxypolycaprolactone mono (meth) acrylate. Specific examples of the compound represented by the general formula (3) include compounds represented by the following formulas (3a) to (3d).

_{CH 2 = C (CH 3)} -COO- (CH 2) 5 -COOH (3a)
_{CH 3 -COO- (CH 2) 5} -COOH (3b)

  Moreover, it is also suitable to use 1 type, or 2 or more types selected from the compound represented by following General formula (4) as a dispersing agent. In addition, one or more compounds represented by the following general formula (4) are used in combination with one or more compounds represented by the above general formula (2) and / or the above general formula (3). May be.

^{R 8 -R 9 -O- (CO-} R 10 -O) d -H (4)
Details of R ⁸ , R ⁹ , R ¹⁰ and d in the general formula (4) are as follows. R ⁸ represents a group selected from a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an aryl group, an aralkyl group, an acyl group, and a (meth) acryloyl group. R ⁹ represents an alkylene group or an aryl group, R ¹⁰ represents an alkylene group, and the structure thereof is preferably linear rather than cyclic, and the carbon number thereof is preferably 3 to 20 carbon atoms. d represents an integer of 1 or more.

  Examples of the compound represented by the general formula (4) include “Placcel FM1” and “Placcel FM5” manufactured by Daicel Chemical Industries, Ltd. The compound represented by the following formula (4a) is represented by the above general formula (4). Specific examples of the compounds represented are listed.

_{CH 2 = C (CH 3)} COOCH 2 CH 2 O [CO (CH 2) 5 O] n H (4a)
In said formula (4a), n represents an average addition mole number and is an integer of 1-10.

Other than the above general formulas (2) to (4), suitable dispersants include —O— (CO—R ⁴ —O) _a —CO—R ⁵ —COOH group (in the group, R ⁴ , R ⁵ , a is the same as R ⁴ , R ⁵ and a in the general formula (2), and —CO— (O—R ⁷ —CO) _b —OH group (in the group, R ⁷ and b are the same as those in the general formula (3) ) R ⁷ and b), or —O— (CO—R ¹⁰ —O) _d —H group (in the group, R ¹⁰ and d are the same as R ¹⁰ and d in formula (4)). The polymer which has is mentioned. The polymer can be obtained by copolymerizing a (meth) acrylic acid ester having _a —O— (CO—R ⁴ —O) _a —CO—R ⁵ —COOH group.

  The content of the dispersant in the resin composition is preferably 0.005% by mass or more and 20% by mass or less, preferably 0.02% by mass or more and 10% by mass or less, more preferably 0.005% by mass or more with respect to the nanoparticles. It is 1 mass% or more and 5 mass% or less. When the content of the dispersant is less than 0.005% by mass, the effect of improving the dispersibility of the dispersant may not be sufficiently exhibited. On the other hand, when the content exceeds 20% by mass, the cured resin composition has a large refractive index. May decrease.

Curable resin Thermosetting resin that cures when heated; Photocurable resin that cures when irradiated with light such as visible light, ultraviolet light, infrared light; and Electron beam curable that cures when irradiated with an electron beam Resin; etc. corresponds to the curable resin in the present invention.

  A known curable resin can be used as the curable resin of the present invention. For example, an epoxy resin, a (meth) acrylic resin, a silicone resin, and the like can be given.

  Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, hydrogenated bisphenol A type epoxy resins, biphenyl type epoxy resins, and other bifunctional glycidyl ether type epoxy resins; Polyfunctional glycidyl ether type epoxy resin such as novolac type epoxy resin, orthocresol novolak type epoxy resin, alkyl-modified triphenolmethane type epoxy resin, tris-hydroxyphenylmethane type epoxy resin, tetraphenylolethane type epoxy resin; Glycidyldiaminidiphenylmethane type epoxy resin, triglycidyl isocyanurate type epoxy resin, aminophenol type epoxy resin, aniline type epoxy resin, toluidine type epoxy resin Glycidylamine type epoxy resins such as xyresins; 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis- (3,4-epoxycyclohexyl) adipate, 1,2,8,9-diepoxy limonene And oxetane resins such as 1,4-bis {[(3-ethyl-3-octacenyl) methoxy] methyl} benzene.

Additives The resin composition of the present invention contains additives as necessary. Examples of such an additive component include known curing agents. When using a curing agent, a known curing accelerator may be used in combination.

  When a curing agent is selected, a photocation polymerization initiator that generates a cationic species or a Lewis acid by ultraviolet rays and / or a cationic species or a Lewis acid by heat is used for the reason that the cured resin composition is excellent in heat resistance. It is preferred to select a thermal cationic polymerization initiator that is generated.

  Examples of the cationic photopolymerization initiator include metal fluoroboron complex salts and boron trifluoride complex compounds described in US Pat. No. 3,379,653; US Pat. No. 3,586,616. Bis (perfluoroalkylsulfonyl) methane metal salts; aryl diazonium compounds as described in US Pat. No. 3,708,296; as described in US Pat. No. 4,058,400 Aromatic onium salts of group VIa elements; aromatic onium salts of group Va elements as described in US Pat. No. 4,069,055; as described in US Pat. No. 4,068,091 Dicarbonyl chelates of group IIIa-Va elements; thiopyrylium salts as described in US Pat. No. 4,139,655; US Pat. Element VIb in the form of an MF6-anion as described in US Pat. No. 61,478 where M is selected from phosphorus, antimony and arsenic; described in US Pat. No. 4,231,951 Arylsulfonium complex salts such as those described above; aromatic iodonium complex salts and aromatic sulfonium complex salts as described in US Pat. No. 4,256,828; R. Bis [4- (Journal of Polymer Science, Polymer Chemistry Edition], Vol. 22, p. 1789 (1984) by Watt et al. Diphenylsulfonio) phenyl] sulfide-bis-hexafluorometal salts (eg, phosphates, arsenates, antimonates, etc.); mixed ligand metal salts of iron compounds; silanol-aluminum complexes; . These ultraviolet polymerization initiators may be used alone or in combination of two or more. Of these ultraviolet polymerization initiators, arylsulfonium complex salts, aromatic iodonium complex salts of halogen-containing complex ions or aromatic sulfonium complex salts, and aromatic onium salts of Group II, Group V and Group VI elements are preferred. Some of these salts are, for example, UVI-6992 (Dow Chemical), FX-512 (3M), UVR-6990, UVR-6974 (Union Carbide), UVE-1014, UVE-1016 ( General Electric, Inc.), KI-85 (Degussa), SP-150, SP-170 (Asahi Denka), Sun-Aid SI-60L, SI-80L, SI-100L (Sanshin Chemical Co., Ltd.) Can be obtained.

  Examples of the thermal cationic polymerization initiator include cationic or protonic acid catalysts such as triflic acid (trifluoromethanesulfonic acid) salt, boron trifluoride ether complex compound, boron trifluoride. These thermal cationic polymerization initiators may be used alone or in combination of two or more. Among these thermal cationic polymerization initiators, triflate is preferable, and specifically, for example, diethylammonium triflate, triethylammonium triflate, diisopropylammonium triflate, triflate available from 3M as FC-520. Ethyl diisopropylammonium acid, etc. (many of which are described in Modern Coatings published October 1980 by RR Alm). Some aromatic onium salts used as a photocationic polymerization initiator generate cationic species by heat, and these photocationic polymerization initiators can also be used as a thermal cationic polymerization initiator. Specifically, for example, Sun-Aid SI-60L, SI-80L, SI-100L (Sanshin Chemical Industry Co., Ltd.) can be mentioned.

  Of these photo and thermal cationic polymerization initiators, onium salts are preferred because of excellent handling properties and a balance between latency and curability, and diazonium salts, iodonium salts, sulfonium salts, and phosphonium salts are particularly preferred. Is preferred.

  It should be noted that the curing agents other than the curing agents exemplified above are polyamides, aliphatic polyamines, cycloaliphatic polyamines, aromatic polyamines, partially modified amines, acid anhydrides. Known curing agents such as compounds, dicyandiamides, imidazoles, amine imides, hydrazides, and novolak-based curing agents (for example, phenol novolac and crenor novolac) are appropriately selected and added to the resin composition according to the present invention. It is also acceptable.

  Examples of additives other than the curing agent include known additives for curable resins such as a colorant, a release agent, a silicone compound, a reactive diluent, a stabilizer, a flame retardant aid, and a crosslinking agent. .

  Moreover, you may use a plasticizer as an additive for the moldability improvement of a resin composition. Specific examples of the plasticizer include phosphate plasticizers such as tributyl phosphate and 2-ethylhexyl phosphate; phthalate plasticizers such as dimethyl phthalate and dibutyl phthalate; butyl oleate, glycerin monoolein Aliphatic monobasic acid ester plasticizers such as acid esters; Aliphatic dibasic acid ester plasticizers such as dibutyl adipate and di-2-ethylhexyl sebacate; Diethylene glycol dibenzoate, triethylene glycol di-2-ethylbutyrate Polyhydric alcohol ester plasticizers such as lath; Oxyacid ester plasticizers such as methyl acetylricinoleate and tributyl acetylcitrate; Chlorinated paraffin; Polypropylene glycol adipate, 1,3-butylene glycol adipate, weight average molecular weight 1000 ~ Polyester plasticizers such as co-condensation polymers of about 15000; epoxy plasticizers such as epoxy alkyl stearates and epoxy triglycerides; stearic acid plasticizers. One of the preferable plasticizers in the case of using an epoxy resin is a polyglycol plasticizer.

(Production method of resin composition)
Production examples of the resin composition according to the present invention are as follows. The production example includes a precursor mixed solution preparation step of preparing a mixed solution of a zirconium oxide precursor and a coating agent (I); hydrothermal reaction to obtain zirconium oxide nanoparticles coated with the coating agent (I) by a hydrothermal reaction. A reaction step; a post-coating step of coating the surface of the zirconium oxide nanoparticles with a coating agent (II); a particle dispersion step of dispersing the nanoparticles obtained in the post-coating step in a curable resin. Hereinafter, the method will be described in the order of steps.

Precursor mixed solution preparation step In this step, at least a zirconium oxide precursor and a coating agent (I) are mixed to prepare a precursor mixed solution containing them. The solvent of the liquid mixture is an organic solvent.

  Examples of the zirconium oxide precursor include zirconium hydroxide, chloride, oxychloride, oxynitrate, sulfide, carboxylate, amino compound salt, and metal alkoxide. Of these zirconium oxide precursors, oxychlorides and oxynitrates that are inexpensive and can obtain fine nanoparticles are preferred. The amount of the zirconium oxide precursor in the precursor mixture is usually about 2% by mass or more and 95% by mass or less. If it is less than 2% by mass, the yield of zirconium oxide may be reduced, and if it exceeds 95% by mass, the amount of solid content in the precursor mixed solution is large, so that subsequent hydrothermal reaction may be difficult to occur. A preferable zirconium oxide precursor amount is about 5% by mass or more and 90% by mass or less.

  As the organic solvent in the precursor mixed solution, one that forms two phases with water is selected. For example, hydrocarbon, ketone, ester, ether, alcohol, amine, carboxylic acid and the like can be used as the organic solvent. Considering the hydrothermal reaction in the next step, an organic solvent having a boiling point of 120 ° C. or higher is suitable. In an organic solvent having a boiling point of less than 120 ° C., the vapor pressure at the time of hydrothermal reaction becomes high, so that the reaction pressure has to be increased, and as a result, aggregation and fusion of zirconium oxide particles may easily occur. Therefore, an organic solvent having a boiling point of 180 ° C. or higher is more preferable, and an organic solvent having a boiling point of 210 ° C. or higher is more preferable. Specific organic solvents include decane, dodecane, tetradecane, octanol, decanol, cyclohexanol, terpineol, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2 , 3-butanediol, hexanediol, octanoic acid, 2-ethylhexanoic acid, neodecanoic acid and the like.

  The precursor mixture can be prepared by the following procedure. The aqueous alkaline solution, the coating agent (I), and the zirconium oxide precursor are mixed and stirred, and then the organic solvent is added and stirred to form an organic solvent phase (oil phase) -water phase. If it collect | recovers, a precursor liquid mixture will be obtained. In this preparation process, it is preferable to stir while heating (for example, 30 to 80 ° C.).

Hydrothermal reaction step In this step, the precursor mixture prepared in the previous step and the water hydrothermal reaction mixture are prepared, and the zirconium oxide nanoparticles coated with the coating agent (I) are prepared by hydrothermal reaction. Prepare.

  Although the kind of water for preparing the liquid mixture for hydrothermal reaction is not particularly limited, it is preferable to use pure water. Since the pH of the water for mixing is preferably 4 or more and 9 or less, the pH of the water may be adjusted by appropriately adding acid, alkali, or the like. The amount of water is preferably such that (number of moles of water) / (number of moles of zirconium) is 4 or more and 100 or less. When the ratio is less than 4, nanoparticles having poor dispersibility may be generated. On the other hand, when the ratio exceeds 100, the amount of water increases, so that the amount of recovered zirconium oxide in one hydrothermal reaction may decrease. The ratio is more preferably 8 or more and 50 or less.

  To the mixed liquid for hydrothermal reaction, carboxylic acid, amine compound, alkoxide, silane coupling agent, titanate coupling agent are used to improve the dispersibility of the zirconium oxide precursor in the precursor mixed liquid phase and / or aqueous phase. An aluminate coupling agent or the like may be added. A suitable addition amount at this time is about 0.01 mol times or more and 2 mol times or less with respect to the zirconium oxide precursor.

  When the prepared liquid mixture for hydrothermal reaction becomes a two-layer in a stationary state, it may be vigorously stirred immediately before the hydrothermal reaction is started to put the liquid mixture in a suspended state.

  In the hydrothermal reaction, when the pressure is 1 MPaG or more, particle aggregation may easily occur, and an apparatus for realizing the pressure is usually expensive. Therefore, in this hydrothermal reaction, fine zirconium oxide particles are produced under relatively mild hydrothermal reaction conditions of less than 1 MPaG. Unlike conventional high-temperature and high-pressure conditions (for example, 400 ° C., 30 MPaG), zirconium oxide particles can be produced under the above-mentioned mild pressure conditions. The precursor mixture prepared in the previous step without using a simple zirconium salt aqueous solution is used. This is because the liquid is used. On the other hand, the lower limit of the pressure in the hydrothermal reaction is preferably 0.1 MPaG, more preferably 0.2 MPaG or more, because if the reaction is performed at normal pressure, high temperature is required for the formation of zirconium oxide crystals and particle aggregation due to heat may be promoted. More preferred.

  The temperature in the hydrothermal reaction may be set so that the pressure in the reaction vessel is less than 1 MPaG in consideration of the boiling point of an organic solvent or the like. Considering the saturated water vapor pressure of water, the reaction is preferably carried out at a temperature of 180 ° C. or lower.

  Although there is no restriction | limiting in particular in the hydrothermal reaction time, Usually, it is about 0.1 hours or more and 10 hours or less, and 0.5 hours or more and 6 hours or less are preferable.

  Further, the reaction system atmosphere is not particularly limited, and a reaction system atmosphere such as air, oxygen, hydrogen, nitrogen, argon, carbon dioxide can be used. Considering suppression of particle aggregation and safety, it is preferable to react in an inert gas atmosphere such as nitrogen or argon.

  As a result of the hydrothermal reaction, zirconium oxide nanoparticles coated with the coating agent (I) are generated and precipitated at the bottom of the aqueous phase. In order to remove by-produced aggregates and precipitated carbon, it is preferable to purify the nanoparticles. For example, the precipitated zirconium oxide nanoparticles are separated by filtration, and then the nanoparticles are dispersed and filtered in toluene or the like, and concentrated under reduced pressure to remove aggregates and carbon. In addition, it is also possible to isolate | separate the organic solvent used in order to manufacture a zirconium oxide nanoparticle, and to reuse this. Such reuse is preferable because the amount of waste liquid and manufacturing cost can be suppressed.

Post-coating step In this step, the zirconium oxide coated with the coating agent (I) and the coating agent (II) is obtained by replacing a part of the coating agent (I) on the surface of the zirconium oxide particles with the coating agent (II). Get nanoparticles. The replacement with the coating agent (II) is performed by dispersing the zirconium oxide nanoparticles in a solvent and then adding and mixing the coating agent (II) in the solvent. At this time, the addition and mixing may be performed at normal temperature, but in order to promote the substitution, it is preferable to perform the addition and mixing in a heated state. When heating, it is preferable to reflux.

  Since the zirconium oxide nanoparticles are coated with the coating agent (I), the particles are highly dispersed in the hydrophobic solvent. For example, the particles are highly dispersed in benzene, toluene, xylene and cyclohexane, and these hydrophobic solvents can be used. If a hydrophilic solvent such as water or alcohol having 4 or less carbon atoms is used, the zirconium oxide nanoparticles may be aggregated. Therefore, the particle dispersion performed in this step is completely different from the conventional dispersion in which highly hydrophilic zirconium oxide particles are dispersed in a hydrophilic solvent.

  The amount of zirconium oxide may be appropriately adjusted and dispersed in a solvent, and the zirconium oxide concentration is preferably about 0.1% by mass or more and 50% by mass or less.

  As the amount of the coating agent (II) added is increased, the amount of the coating agent (II) covering the zirconium oxide nanoparticles tends to increase. The amount of coating agent (II) added is appropriately adjusted according to the tendency. The amount added is usually such that the coating amount of the coating agent (II) on the zirconium oxide nanoparticles coated with the coating agent (I) is 1% by mass or more and 40% by mass or less. If the coating amount of the coating agent (II) is less than 1% by mass, the amount of the coating agent (II) may be insufficient, and the dispersibility of nanoparticles in a solvent other than a nonpolar organic solvent such as toluene may not be improved. is there. On the other hand, when it exceeds 40% by mass, the amount of the coating agent (II) on the nanoparticle surface may be excessive. More preferably, the coating amount of the coating agent (II) is 3% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 25% by mass or less.

  When heating after the addition of the coating agent (II), the temperature is appropriately adjusted. Usually, the temperature is about 30 ° C. or more and less than 200 ° C., more preferably 40 ° C. or more and less than 180 ° C., and further preferably 50 ° C. or more and less than 160 ° C. The heating time is also adjusted appropriately. Usually, it is 0.1 hours or more and less than 10 hours, more preferably 0.3 hours or more and less than 6 hours. In addition, when recirculating | refluxing, it is good to control by the boiling point of the solvent currently used, and pressure reduction-pressurization adjustment of a gaseous-phase part.

  Zirconium oxide nanoparticles coated with the coating agent (I) and the coating agent (II) are produced by the reflux. As a method for recovering the nanoparticles, (1) the solvent is distilled off under reduced pressure, and (2) the nanoparticles are aggregated or precipitated by adding a solvent having low affinity with the nanoparticles, and the aggregated particles are filtered. There is a method of collecting separately.

Particle Dispersion Step In the particle dispersion step, a curable resin and nanoparticles are mixed to prepare a resin composition according to the present invention. In this case, a dispersant is also mixed if necessary. Even if the nanoparticles are directly mixed with the curable resin, the resin composition according to the present invention can be obtained. However, when the viscosity of the curable resin at room temperature or heated is high, the nanoparticles may not be easily dispersed. . Therefore, in the particle dispersion step in this production example, in order to easily disperse the nanoparticles, the curable resin and the nanoparticles are added to and mixed with the solvent (if necessary, the dispersant is also mixed), and the solvent is removed.

  As the solvent used in this step, one or two or more of those which are removed by means such as distillation under reduced pressure and in which nanoparticles are dispersed is appropriately selected. For example, alcohols such as methanol, ethanol and n-propanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate and propyl acetate; ethers such as ethylene glycol monomethyl ether; benzene, toluene, xylene, ethylbenzene and cyclohexane Hydrocarbons; halogenated hydrocarbons such as dichloromethane and chloroform; amides such as dimethylformamide and N, N-dimethylacetamide; and water. And the usage-amount of a solvent is suitably selected according to the amount of nanoparticles.

(Use of resin composition)
The resin composition of the present invention and the production examples thereof are as described above. The molded body of the resin composition according to the present invention in which nanoparticles are highly dispersed exhibits properties such as high refractive index and high light transmittance. Therefore, the utility value of the molded body produced by curing the resin composition according to the present invention is high. The molded body is made into a lens for an in-vehicle camera, a PC camera, a digital camera, a mobile phone, a digital video, a surveillance camera, etc .; an optical fiber; an optical waveguide; an optical filter; an optical adhesive; Can be used as an optical material such as a light diffusion plate.

  As above-mentioned, the molded object of the resin composition which concerns on this invention shows the property of a high refractive index and a high light transmittance. By adjusting the thickness of the molded product produced from the resin composition of the present invention, the visible light transmittance of the molded product can be 80% or more, and the haze value can be 10% or less. The rate can be 85% or more and the haze value can be 5% or less.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the following examples, and may be appropriately modified and implemented within a range that can meet the purpose described above and below. All of which are within the scope of the present invention.

(Nanoparticles)
As in the following production example, zirconium oxide particles coated with the coating agent (I) and / or the coating agent (II) were prepared.

Production Example 1: Preparation of Zirconium Oxide Particles Coated with Coating Agent (I) 100 g of sodium hydroxide (manufactured by Kishida Chemical Co., Ltd., special grade) was added to 700 g of stirred pure water at 40 ° C. and dissolved. . Next, 495 g of neodecanoic acid (manufactured by Japan Epoxy Resin Co., Ltd.) as a coating agent (I) was added with stirring to prepare a sodium neodecanoate aqueous solution. The solution was to 80 ° C., under stirring zirconium oxychloride octahydrate (first Kigenso Kagaku Kogyo Co., Ltd. ZrOCl ₂ · 8H ₂ O "ZIRCOSOL ZC-20") 740 g, was added over 20 min, 80 ° C. When stirring was continued for 1 hour and a half, white and highly viscous zirconium neodecanoate was formed. Next, when 1270 g of tetradecane was added and stirred, a solution composed of two phases of an oil phase (a phase containing zirconium neodecanoate and tetradecane) and an aqueous phase was obtained. The aqueous phase was separated and removed, and the oil phase portion was recovered. The oil phase part thus obtained was washed 3 times with pure water. Next, 1000 g of an oil phase and 500 g of pure water were charged into an autoclave equipped with a stirrer, and the atmosphere in the reaction vessel was replaced with nitrogen gas. Then, it heated to 175 degreeC and made it react for 3 hours. The pressure in the container during the reaction at 175 ° C. was 0.9 MPa. The solution after the reaction was taken out and the bottom precipitate was collected by filtration. The precipitate was washed with acetone, dried, and then dispersed in toluene to give a cloudy solution. Next, it filtered again with the quantitative filter paper (Advantech Toyo Co., Ltd. No. 5C) as a refinement | purification process, and removed the coarse particle etc. in a deposit. Thereafter, the toluene in the filtrate was removed under reduced pressure to recover zirconium oxide particles coated with the white coating agent (I).

Production Example 2: Production of Zirconium Oxide Particles Coated with Coating Agent (I) and Coating Agent (II) 12.3 g of zirconium oxide particles coated with the coating agent (I) obtained in Production Example 1 above were added to toluene. A solution was prepared by dispersing in 87.7 g, and 4 g of phenyltrimethoxysilane (KBM-103 manufactured by Shin-Etsu Chemical Co., Ltd.) as a coating agent (II) and 4 g of ultrapure water were added to the solution. The mixture was refluxed with stirring for an hour. After allowing the solution after the reflux treatment to cool, the dispersed particles were aggregated by adding n-hexane to make the solution cloudy. Next, the agglomerated particles were separated from the white turbid solution with a filter paper, and then vacuum-dried at room temperature to prepare zirconium oxide particles coated with the coating agent (I) and the coating agent (II).

Production Example 3: Production of zirconium oxide particles coated with coating agent (I) and coating agent (II) (1)
The coating agent (II) was coated with the coating agent (I) and the coating agent (II) in the same manner as in Production Example 2 except that the amount of phenyltrimethoxysilane was 16 g and the amount of ultrapure water was 16 g. Zirconium oxide particles were prepared.

Production Example 4: Production of zirconium oxide particles coated with coating agent (I) and coating agent (II) (2)
As coating agent (II), except that phenyltrimethoxysilane 1.91 g and diphenyldimethoxysilane (KBM-202SS manufactured by Shin-Etsu Chemical Co., Ltd.) 3.82 g were used, and the amount of ultrapure water used was 5.73 g. In the same manner as in Production Example 2, zirconium oxide particles coated with the coating agent (I) and the coating agent (II) were prepared.

  The following crystal structure analysis was performed on the particles obtained in the above Production Examples 1 to 4.

Crystal structure analysis Using a fully automatic multipurpose X-ray diffractometer (Spectre Pro, manufactured by Spectris), measurement was performed under the following conditions.
X-ray source: CuKα (0.154 nm)
X-ray output setting: 45kV, 40mA
Step size: 0.017 °
Scan step time: 5.08 seconds Measurement range: 5-90 °
Measurement temperature: 25 ° C
In any analysis result of the particles of Production Examples 1 to 4, diffraction lines attributed to the tetragonal and monoclinic crystal structures of zirconium oxide were detected. From the intensity of the diffraction lines, it was confirmed that any zirconium oxide was mainly composed of tetragonal crystals and slightly monoclinic crystals.

Particle size The particles were observed with an ultra-high resolution field emission scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation). Arbitrarily 100 particles observed to be enlarged were selected, the length of each particle in the major axis direction was measured, and the average value was taken as the average particle diameter. In any of the particles of Production Examples 1 to 4, the average particle size was 5 nm.

Coating agent Analysis was performed with a Fourier transform infrared spectrophotometer. As a result, as for the particles of Production Example 1, absorption derived from C—H and absorption derived from COOH were observed, and it was confirmed that the zirconium oxide particles were coated with neodecanoic acid. Moreover, about the particle | grains of manufacture examples 2-4, the absorption derived from C-H and COOH of neodecanoic acid and the absorption derived from Si-OC of phenyltrimethoxysilane and / or diphenyldimethoxysilane are recognized. It was confirmed that the zirconium oxide particles were covered with neodecanoic acid and phenyltrimethoxysilane, or neodecanoic acid, phenyltrimethoxysilane and diphenyldimethoxysilane.

Organic component amount By TG-DTA (thermogravimetric-differential thermal analysis), the temperature was raised to 800 ° C at a rate of 10 ° C / min in an air atmosphere, and the mass reduction rate of the particles was measured. It was. The amount of organic components in the particles of Production Example 1 was 19% by mass, 17% by mass for the particles of Production Example 2, 19% by mass for the particles of Production Example 3, and 15% by mass for the particles of Production Example 4.

Ratio of coating agent (II) (Aromatic H area ratio)
Particle-dispersed deuterated chloroform was used as a measurement sample and analyzed by ¹ H-NMR (“Unity Plus” manufactured by Varian, resonance frequency: 400 MHz, integration number: 16, reference substance: tetramethylsilane). And the percentage of the aromatic proton peak (8-6 ppm peak) area with respect to the total proton peak area in the ¹ H-NMR chart was determined. As a result, it was 0% for the particles of Production Example 1, 54% for the particles of Production Example 2, 84% for the particles of Production Example 3, and 49% by mass for the particles of Production Example 4.

(Resin compositions of Examples and Comparative Examples)
By mixing a predetermined amount (see Table 1 below) of the particles, epoxy resin, and dispersant obtained in any of Production Examples 1 to 4 with 10 parts by mass of toluene, the toluene is distilled off at 90 ° C. under reduced pressure. Resin compositions of Examples and Comparative Examples were prepared. And 0.05 mass part of stearic acid was added to the said resin composition as a mold release agent, and it mixed at 80 degreeC. After cooling this mixture to 50 ° C., 0.01 parts by mass of a cationic polymerization initiator (“San-Aid SI80L” manufactured by Sanshin Chemical Industry Co., Ltd.) was further added and mixed. Thereafter, the resin composition was placed under reduced pressure to perform defoaming treatment.

  The epoxy resin used in the preparation of the resin composition is a bisphenol A type epoxy resin “JER828EL” manufactured by Japan Epoxy Resin Co., which is represented by the following formula (5a), and manufactured by Japan Epoxy Resin Co., which is represented by the following formula (5b). Hydrogenated bisphenol A type epoxy resin “Epicoat YX-8000”, an aliphatic cyclic epoxy resin “Celoxide 2021P (3,4-epoxycyclohexylmethyl-3,4-epoxy) represented by the following formula (5c)” Cyclohexanecarboxylate) ”or an oxetane resin“ ENTERNACOLL OXBP ”represented by the following formula (5d).

  The dispersant used in the preparation of the resin composition is “Placcel FM-1” manufactured by Daicel Chemical Industries, which is a compound of n = 1 represented by the above formula (4a), and represented by the above formula (4a). The “Plexel FM-5” manufactured by the same company, which is a compound of n = 5, or the dispersant A represented by the above formula (2a). Dispersant A was prepared by mixing 1.20 g of caprolactone-modified adducted hydroxyethyl methacrylate ("Placcel FM-1" manufactured by Daicel Chemical Industries, Ltd.), 7.8 g of succinic anhydride, and 0.2 g of triphenylphosphine. A dispersant obtained by heating at 80 ° C. for 4 hours below (no succinic anhydride was detected in the gas chromatographic analysis after the heating).

(Production of film)
Using the resin compositions of Examples and Comparative Examples subjected to the defoaming treatment, films were produced as follows. Using an applicator, 10 mil of the resin composition was formed on the glass surface. This film was cured at 150 ° C. for 3 hours. At this time, when bubbles were generated due to the presence of the solvent, a decompression treatment was also performed. The cured film was peeled from the glass plate to obtain a film having a thickness of 250 μm.

  The light transmittance (light wavelength: 589 nm) in the thickness direction of the film was measured using an absorptiometer (a spectrophotometer “UV-3100” manufactured by Shimadzu Corporation). The measurement results are shown in Table 1 below.

In Table 1, the following can be confirmed.
(1) In the case of having no dispersant, the transmittances of Examples 5 and 6 having the coating agent (II) are clearly higher than the transmittance of Comparative Example 1 having no coating agent (II). high.
(2) Similar to the above (1), even in the case of having a dispersant, transmission of Examples 1 to 4 and 7 to 11 having the coating agent (II) rather than Comparative Example 2 having no coating agent (II) The rate is clearly high. Therefore, it can be confirmed that the dispersibility of the zirconium oxide particles having the coating agent (I) and the coating agent (II) is remarkably high. In addition, the item (2) shows that even when a dispersant is used, excellent transmittance cannot be realized (the use of the dispersant includes not only the coating agent (I) but also the coating agent). (It means that the use of (II) is necessary.)
(3) From the comparison between Example 5 and Example 6, it can be confirmed that the transmittance increases as the aromatic H area ratio increases.

Claims (12)

Having zirconium oxide nanoparticles coated with coating agent (I) and coating agent (II), and a curable resin,
The resin composition, wherein the coating agent (I) is a carboxylic acid represented by the following general formula (1).
R ¹ —COOH (1)
(In general formula (1), R ¹ represents a hydrocarbon group having 6 or more carbon atoms.)   2. The resin composition according to claim 1, wherein one type of the coating agent (II) is an organometallic compound having a metal atom and a hydrolyzable group bonded to the metal atom.   The resin composition according to claim 2, wherein a group having an aromatic ring is bonded to a metal atom of the organometallic compound. 4. The resin composition according to claim 3, wherein a peak area of the ¹ H-NMR chart of the zirconium oxide nanoparticles and an area ratio based on the following formula are 40% or more.

  The resin composition according to claim 1, wherein the zirconium oxide nanoparticles include tetragonal zirconium oxide.   The resin composition of any one of Claims 1-5 in which the dispersing agent is contained. The resin composition according to claim 6, wherein the dispersant is one or more compounds selected from compounds represented by the following general formulas (2) to (4).
^{R 2 -R 3 -O- (CO-} R 4 -O) a -CO-R 5 -COOH (2)
(In General Formula (2), R ² represents a group selected from a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an aryl group, an aralkyl group, an acyl group, and a (meth) acryloyl group. R ³ represents an alkylene group or an aryl group, R ⁴ represents an alkylene group, R ⁵ represents a group selected from an alkylene group, an aryl group, and an alkyne group, and a represents an integer of 1 or more. .)
R ⁶ — [CO— (O—R ⁷ —CO) _b —OH] _c (3)
(In General Formula (3), R ⁶ is a hydrogen atom, a halogen atom, an alkyl group that may have a substituent, an aryl group, an aralkyl group, an acyl group, and a vinyl group that may have a substituent. R ⁷ represents an alkylene group, b represents an integer of 1 or more, and c represents an integer of 1 to 4.)
^{R 8 -R 9 -O- (CO-} R 10 -O) d -H (4)
(In the general formula (4), R ⁸ represents a group selected from a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an aryl group, an aralkyl group, an acyl group, and a (meth) acryloyl group. R ⁹ represents an alkylene group or an aryl group, R ¹⁰ represents an alkylene group, and d represents an integer of 1 or more.)   The resin composition according to claim 1, wherein the curable resin has an epoxy resin.   The resin composition according to claim 8, wherein the resin composition is a resin composition for optical materials.   The molded object manufactured by hardening the resin composition of Claim 8 or 9.   A lens produced by curing the resin composition according to claim 9. An optical component comprising the lens according to claim 11.