JP6198379B2 - Modified zirconia fine particle powder, modified zirconia fine particle dispersed sol and method for producing the same - Google Patents

Description

  The present invention relates to a modified zirconia fine particle powder excellent in dispersibility and fluidity, a dispersion using the modified zirconia fine particle powder, and a production method thereof.

  Conventionally, colloidal particles such as silica, alumina, titania, zirconia, zinc oxide, antimony pentoxide, cerium oxide, tin oxide, silica-alumina, silica-zirconia, etc. are known, and to adjust the refractive index as an optical material It is blended and used for coatings. For example, silica is used as a low refractive index material, alumina is used as a medium refractive index material, and titania, zirconia, and the like are used as high refractive index materials.

  Although titania particles have a high refractive index, there are problems in light resistance, weather resistance and the like because of poor dispersion stability and titania itself having photocatalytic activity. For this reason, the dispersion stability, light resistance, weather resistance and the like are improved by compounding other components such as a silica component together with titania (Patent Document 1: JP-A-8-48940). Issue gazette). However, depending on the composite component, in addition to lowering the refractive index, it is difficult to completely suppress the photocatalytic activity, so that the light resistance, weather resistance, etc. may be insufficient. (Patent Document 1)

  Therefore, it is attempted to use zirconia instead of titania. However, although zirconia particles have substantially no photocatalytic activity and are excellent in light resistance, weather resistance, etc., they are colloids excellent in dispersibility and stability. It was difficult to obtain a zirconia sol in the region.

The present applicant has disclosed a method for producing a zirconia sol having excellent dispersibility by hydrothermally treating a hydrolyzate of a zirconium salt in the presence of a particle growth inhibitor such as carboxylic acid. (Patent Document 2: Japanese Patent Laid-Open No. 2006-143535) Further, a method for producing a zirconia sol having excellent stability by hydrolyzing zirconium ammonium carbonate in the presence of carboxylic acid or the like is disclosed. (Patent Document 3: Japanese Patent Laid-Open No. 3-174325)
However, the zirconia fine particles obtained by the above-described method are strongly aggregated when dried, and the desired dispersibility cannot be obtained.

  On the other hand, zirconia fine particles obtained by calcining zirconium hydroxide at high temperature and pulverizing them to obtain fine particles have a high refractive index, but the particle size is too large, the particle size distribution is not uniform, or there are aggregated particles. In view of the poor dispersibility, it is not suitable for use in a transparent film. This method is also known to have effects such as the addition of alkali or the like (grinding aid) at the time of pulverization to reduce the particle size or to make the particle size distribution uniform.

  Conventionally, surface treatment with an organosilicon compound (silane coupling agent) has been performed to improve the dispersibility and stability of various metal oxide sols, but the above-mentioned zirconia fine particles obtained by firing and pulverization Can be stably dispersed in the alkali region in the presence of alkali, but there is a problem that when washing and purification are carried out and the alkali component is removed, the surface potential is lowered and the dispersibility is significantly lowered.

  In particular, in the presence of alkali, which is a catalyst for hydrolysis of organosilicon compounds, the surface-treated zirconia fine particles were treated with the resulting surface treatment because of the presence of alkali ions, resulting in non-uniform organosilicon compound treatment on the surface. The dispersibility and stability of the zirconia fine particles were not always sufficient.

  On the other hand, when alkali is not present, that is, when a hydrolysis catalyst is not used, the hydrolysis rate is slow with a trifunctional or lower organosilicon compound, the unreacted organosilicon compound remains, and the surface treatment is insufficient. There was a case.

Moreover, when an acid is used as a hydrolysis catalyst, there is a tendency to form a chain hydrolyzate on the particle surface, and the resulting particles may aggregate or have poor dispersibility.
Further, the applicant of the present application can efficiently treat the surface by firing the zirconia particles, then pulverizing them in the presence of alkali, treating with NH ₄ type ion exchange resin, and then treating with an organosilicon compound. It discloses that an organic solvent dispersion of modified zirconia fine particles having excellent dispersibility and stability can be obtained. (Patent Document 4: JP2009-132919A)

JP-A-8-48940 JP 2006-143535 A JP-A-3-174325 JP 2009-132819 A

  By the way, in view of the affinity between the zirconia fine particles and the hydrophobic resin or the like, it is desirable to treat with a trifunctional or lower organosilicon compound. However, conventional treatment with a trifunctional or lower organosilicon compound may result in insufficient surface treatment and dispersibility in a hydrophobic resin.

  Usually, the surface treatment with a trifunctional or lower organosilicon compound was performed in the presence of an alkali such as ammonia as a hydrolysis catalyst, but it strongly aggregates when dried to a powder, and in addition, the powder flows. In some cases, it was not possible to uniformly disperse in an organic solvent or an organic resin due to low properties. For this reason, after treating with an organosilicon compound, it is necessary to replace the solvent with an organic solvent without drying and then make a dispersion mixed with an organic resin. Nevertheless, the dispersibility in the dispersion is not uniform. In some cases, the stability is insufficient.

  In view of such problems, the present invention is that modified zirconia fine particles having excellent dispersibility in a hydrophobic resin or the like can be obtained by grasping the surface treatment state in a trifunctional or lower organosilicon compound. They thought.

  Although the tetrafunctional organosilicon compound is hydrolyzed without a hydrolysis catalyst, dispersibility may be improved by the alkyl group in the alkoxide remaining unhydrolyzed, but the obtained zirconia powder is strong. In some cases, aggregation occurred and fluidity and dispersibility could not be obtained.

In view of the above problems, the present inventors have intensively studied how to obtain a zirconia fine particle powder excellent in dispersibility when a trifunctional or lower organosilicon compound is used for surface treatment. As a result, it was found that by observing the ²⁹ Si MAS NMR spectrum of the surface, it was possible to grasp the surface treatment state of a trifunctional or lower organosilicon compound.

When a trifunctional or lower organosilicon compound is used using an ammonia catalyst in the presence of a normal solvent such as methanol, the ²⁹ Si MAS NMR spectrum becomes very sharp. In contrast, the ²⁹ Si MAS NMR spectrum peak is broad, and the half-value width of the main peak is in the range of 3 to 15 ppm, so that trifunctional or less organosilicon compounds are sufficiently present on the particle surface and unreacted. The present inventors have found that a product having a small amount of material and a high affinity for a hydrophobic solvent / resin can be obtained, and the present invention has been completed.

  Such surface treatment is performed by adding a predetermined amount of an organosilicon compound to a mixed solvent dispersion of zirconia fine particles such as water / alcohol, and then drying (solvent) under reduced pressure or in a fluid state without adding a catalyst. It has been found that this can be achieved by removing.

[1] A powder of modified zirconia fine particles surface-treated with an organosilicon compound, having an average secondary particle diameter (D _M2 ) in the range of 5 to 500 nm and an average primary particle diameter (D _M1 ) of 5 It is in the range of 500 nm, and the ratio (D _M2 ) / (D _M1 ) of the average secondary particle size (D _M2 ) to the average primary particle size (D _M1 ) is in the range of 1-10. Zirconia fine particle powder.
[2] The organosilicon compound is an organosilicon compound represented by the following formula (1):
The content of the organosilicon compound in the fine particles is in the range of 1 to 50% by weight as R _n -SiO _{(4-n) / 2} (n is an integer of 1 to 3), and the main peak of the ²⁹ Si MAS NMR spectrum The modified zirconia fine particle powder according to [1], wherein the full width at half maximum is 3 to 15 ppm.
_{R n -SiX 4-n (1} )
(In the formula, R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, and may be the same or different from each other. X: an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, Halogen, hydrogen, n: an integer of 1 to 3)

[3] The modified zirconia fine particles are added to the water and / or organic solvent dispersion of the zirconia fine particles without adding the organosilicon compound hydrolysis catalyst. The modified zirconia fine particle powder according to [1] or [2], which is prepared by drying without solvent substitution.
[4] The modified zirconia fine particle powder according to [3], wherein the drying is performed at 200 ° C. or lower under reduced pressure or flow.
[5] The modified zirconia fine particle powder according to [1] to [4], wherein an angle of repose is 45 ° or less.
[6] A modified zirconia fine particle dispersion, wherein the modified zirconia fine particle powder of [1] to [5] is dispersed in an organic solvent and / or an organic resin.
[7] The modified zirconia fine particle dispersion of [6], wherein the concentration of the modified zirconia fine particles is in the range of 1 to 70% by weight as a solid content.

[8] A powder of modified zirconia fine particles having the following steps (d) to (f) and surface-treated with an organosilicon compound, and having an average secondary particle diameter (D _M2 ) in the range of 5 to 500 nm. Yes, the average primary particle size (D _M1 ) is in the range of 5 to 500 nm, and the ratio of the average secondary particle size (D _M2 ) to the average primary particle size (D _M1 ) (D _M2 ) / (D _M1 ) is The manufacturing method of the modified zirconia fine particle powder characterized by being in the range of 1-10.
(D) Step of preparing water and / or organic solvent dispersion of zirconia fine particles (e) Step of adding an organosilicon compound represented by the following formula (1) without adding a hydrolysis catalyst of the organosilicon compound ( f) Step of drying without solvent substitution R _n —SiX _4-n (1)
(In the formula, R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, and may be the same or different from each other. X: an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, Halogen, hydrogen, n: an integer of 1 to 3)
[9] The organosilicon compound is an organosilicon compound represented by the following formula (1):
The content of the organosilicon compound in the resulting fine particles is in the range of 1 to 50% by weight as R _n —SiO 2 _{(4-n) / 2} (n is an integer of 1 to 3), and the main component of ²⁹ Si MAS NMR spectrum [9] The method for producing modified zirconia fine particle powder according to [9], wherein the peak half-value width is in the range of 3 to 15 ppm.
_{R n -SiX 4-n (1} )
(In the formula, R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, and may be the same or different from each other. X: an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, Halogen, hydrogen, n: an integer of 1 to 3)

[10] The average particle diameter (D _Z ) of the zirconia fine particles (before modification) used in the step (d) is in the range of 5 to 400 nm, and the ratio (D D to the average secondary particle diameter (D _M2 )) [2] A process for producing modified zirconia fine particle powder of [8] or [9], wherein ( _M2 ) / (D _Z ) is 0.2-5.
(The average particle size (D _Z ) is measured by the dynamic light scattering method by ultrasonically dispersing a water content of 10% by weight using water as a dispersion medium.)
[11] The method for producing the modified zirconia fine particle powder according to [8] or [9], wherein the drying in the step (f) is performed at 200 ° C. or lower under flow or reduced pressure.
[12] The method for producing modified zirconia fine particle powder of [8] to [11], wherein the zirconia fine particles used are produced by the following steps (a) to (c).
(A) Step of peptizing or dissolving zirconium hydroxide gel in the presence of potassium hydroxide and hydrogen peroxide (b) Step of hydrothermal treatment (c) Step of washing
[13] The method for producing modified zirconia fine particle powder according to [12], wherein in the step (b), hydrothermal treatment is performed in the presence of a particle growth regulator.
[14] The method for producing the modified zirconia fine particle powder according to [12] or [13], wherein the hydrothermal treatment temperature in the step (b) is in the range of 40 to 300 ° C.

  According to the present invention, modified zirconia fine particle powder excellent in dispersibility and fluidity, modified zirconia fine particle dispersion excellent in uniform dispersibility and dispersion stability, modified zirconia fine particle powder, and modified zirconia fine particle dispersion. A manufacturing method can be provided.

  The modified zirconia fine particle powder of the present invention is excellent in fluidity, and can be easily and uniformly monodispersed in an organic solvent, an organic resin, or the like as a direct powder. The modified zirconia fine particle powder is often used as an organic solvent and / or organic resin dispersion, but can be used as a dispersion immediately before use and can be stored as a modified zirconia fine particle powder, so that the storage is safe. There is no need for transportation as a dispersion, transportation is safe, transportation costs can be reduced, and the economy is excellent.

The conceptual diagram of the surface state of the modified zirconia fine particle powder (Example 6) which concerns on this invention is shown. The conceptual diagram of the surface state of the modified zirconia fine particle powder (comparative example 4) processed by the conventional method is shown. It shows a chart of ²⁹ Si MAS NMR spectrum of modified zirconia particles of Example 6. The chart of the ²⁹ Si MAS NMR spectrum of the modified zirconia fine particles of Comparative Example 4 is shown.

The modified zirconia fine particles according to the present invention will be first described below.
[Modified zirconia fine particles]
The modified zirconia fine particle powder according to the present invention is a powder of modified zirconia fine particles surface-treated with an organosilicon compound.

The powder according to the present invention has an average secondary particle size (D _M2 ) in the range of 5 to 500 nm, an average primary particle size (D _M1 ) in the range of 5 to 500 nm, and an average secondary particle size (D _M2). ) And the average primary particle diameter (D _M1 ) (D _M2 ) / (D _M1 ) is in the range of 1 to 10, preferably 1 to 7.

The average secondary particle diameter (D _M2 ) in the present invention is evaluated by a dynamic light scattering method using methanol as a dispersion medium, adjusting the solid content concentration to 30% by weight, and ultrasonically dispersing. The average primary particle size (D _M1 ) is determined by measuring the particle size of 100 particles of TEM observation and determining the average value.

When the ratio is within the range (D _M2 ) / (D _M1 ), the degree of aggregation of the modified zirconia fine particles is low, the dispersibility in the organic solvent and / or the organic resin is high, and the dispersibility is high.
If the ratio (D _M2 ) / (D _M1 ) is too large, it indicates that the degree of aggregation of the modified zirconia fine particles is high, and dispersibility in an organic solvent and / or organic resin may be insufficient. The body is low in transparency and dispersion stability may be insufficient. (D _M2 ) / (D _M1 ) is usually not less than 1.

  When evaluated with a methanol dispersion, the modified zirconia fine particle powder of the present invention has good dispersibility, so that it can be dispersed and the average particle diameter and dispersibility can be evaluated with good reproducibility. Note that there is no significant difference even when other organic solvents are used. However, when evaluated with an aqueous dispersion after the surface treatment, the dispersibility is low and aggregation occurs, so that the average particle diameter cannot be measured, resulting in a result greatly deviating from the primary particle diameter measured by TEM observation.

As the organosilicon compound, a hydrolyzable organosilicon compound represented by the following formula (1) is used.
_{R n -SiX 4-n (1} )
R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms and may be the same as or different from each other. Examples of the unsubstituted hydrocarbon group include an alkenyl group having a double bond in addition to an alkyl group and a cycloalkyl group. Examples of the substituted hydrocarbon group include a substituent such as epoxy, glycidoxy, (meth) acryloxy, urethane, amino, amide, imide, ureido, and the like, or a group in which the hydrogen of the hydrocarbon group is substituted with a halogen such as fluorine. .

  X represents any one of an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, a halogen, and a hydrogen atom, and n is an integer of 1 to 3. When n is 2 or more, Rs may be the same as or different from each other, and a plurality of Xs may be the same as or different from each other.

  Thus, the modified zirconia fine particle powder excellent in fluidity | liquidity and dispersibility can be obtained by using a 1-3 functional organosilicon compound. In the case of a tetrafunctional organosilicon compound, hydrophobic functional groups do not remain, and the modified zirconia fine particle powder strongly aggregates, and fluidity and dispersibility may not be obtained in some cases.

  Specific examples of the organosilicon compound include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, and isobutyltrimethoxysilane. Methoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (βmethoxyethoxy) silane, 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxymethyltrimethoxysilane, γ-glycidoxymethyltrioxysilane, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxyethylate Liethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ- (β-glycidoxyethoxy) propyltrimethoxysilane, γ- (meth) acrylooxymethyltrimethoxy Silane, γ- (meth) acrylooxymethyltriethoxysilane, γ- (meth) acrylooxyethyltrimethoxysilane, γ- (meth) acryloxyethyltriethoxysilane, γ- (meth) acryloxypropyl Trimethoxysilane, γ- (meth) acrylooxypropyltriethoxysilane, butyltrimethoxysilane, isobutyltriethoxysilane, hexyltriethoxysilaoctyltriethoxysilane, decyltriethoxysilane, butyltriethoxysilane, isobutyltriethoxysilane , Hexitole Toxisilane, octyltriethoxysilane, decyltriethoxysilane, 3-ureidoisopropylpropyltriethoxysilane, perfluorooctylethyltrimethoxysilane, perfluorooctylethyltriethoxysilane, perfluorooctylethyltriisopropoxysilane, trifluoropropyltri Examples include methoxysilane, γ-mercaptopropyltrimethoxysilane, trimethylsilanol, methyltrichlorosilane, and the like, and mixtures thereof.

  Among them, γ- (meth) acrylooxymethyltrimethoxysilane, γ- (meth) acrylooxymethyltrioxysilane, γ- (meth) acrylooxyethyltrimethoxysilane, γ- (meth) acrylooxy Acrylic or methacrylic organosilicon compounds such as ethyltriethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, and γ- (meth) acryloxypropyltriethoxysilane are fluid and dispersible. Since the modified zirconia fine particle powder excellent in the above can be obtained, it can be suitably used.

When surface treatment is carried out under specific conditions using an organosilicon compound such as these, the main peak of the ²⁹ Si MAS NMR spectrum becomes broad and the half width is in the range of 3 to 15 ppm.

In the modified zirconia fine particle powder according to the present invention, the half-value width of the main peak of the ²⁹ Si MAS NMR spectrum is 3 to 15 ppm, and more preferably 3.5 to 12 ppm.

In the ²⁹ Si MAS NMR spectrum of the modified zirconia fine particle powder surface-treated with an organosilicon compound, usually two or more peaks having different chemical shift values derived from Si of the organosilicon compound are measured. Means the peak with the highest peak height. Depending on the conditions, one peak may be measured.

  When the half width at the main peak is less than the lower limit, the peak becomes sharp. Such modified zirconia fine particles are in a surface state close to zirconia fine particles modified by hydrolyzing an organosilicon compound (silane coupling agent) in the presence of a catalyst, and the resulting powder is aggregated or reposes. The corners are high and the fluidity is insufficient, and the dispersibility in organic solvents and / or organic resins may be insufficient.

In modified zirconia fine particles with silicon atom particle surfaces to each other organosilicon compounds of the present invention, to increase the ²⁹ Si MAS NMR spectrum width, i.e. densely present in proximity to bind to a degree that affects the nuclear spin of the silicon atom In contrast, the surface-treated zirconia powder obtained by the conventional surface treatment method is presumed to have a relatively small interaction on the surface of the organosilicon compound particles.

These comparisons are shown in FIGS. 1 and 2 as model diagrams.
FIG. 1 is a schematic diagram of the surface of the modified zirconia fine particles of the present invention. Organosilicon compounds are connected as —O—Si—O—Si— on the particle surface, and R on the surface of the zirconia particle. It is considered that the constituent C═O and —COO— interact with the surface OH, and as a result, the organosilicon compounds are gathered near the surface of the zirconia particles. Moreover, it is considered that polycondensation between organosilicon compounds is also progressing. As a result, in the modified zirconia fine particle powder of the present invention, the organic silicon compound is in a state where the particle surface is densely coated, or it is difficult to agglomerate and is excellent in dispersibility in an organic solvent and / or an organic resin. Is considered to have a small angle of repose and excellent fluidity.

  FIG. 2 shows a surface treatment using an ammonium catalyst in the presence of methanol. The OH group on the surface of the zirconia fine particles and the organosilicon compound are polycondensed. Although organosilicon compounds are also polycondensed to form —Si—O—Si—, it is considered that many residues of hydrolyzable groups corresponding to X in formula (1) are also detected.

The content of the organosilicon compound in the modified zirconia fine particles varies depending on the particle diameter of the zirconia fine particles, the kind of the organosilicon compound, etc., but R _n -SiO _{(4-n) / 2} (n is an integer of 1 to 3 ₎ 1) to 50% by weight, more preferably 2 to 40% by weight.

  When the content of the organosilicon compound is small, strongly agglomerated modified zirconia fine particles may be obtained, the fluidity (evaluation of the angle of repose in this application) is low, and the dispersibility in organic solvents, organic resins, etc. is low, Even when dispersed, a uniformly monodispersed dispersion may not be obtained. For this reason, even when a transparent coating film is formed using modified zirconia fine particles, transparency, haze, film strength, scratch resistance, and the like may be insufficient. Even if the content of the organosilicon compound is too large, the organosilicon compound effectively bonded to the surface of the zirconia fine particles does not increase, and the fluidity, the dispersibility in the organic solvent and / or the organic resin are further improved. In addition to the increase in the amount of organic silicon compound itself, for example, the amount of unreacted organic silicon compound and the reaction product between the organic silicon compounds increases, and the fluidity of the modified zirconia fine particle powder, the organic solvent and / or the organic resin. The effect of further improving the dispersibility may not be obtained, and in addition, depending on the application of the modified zirconia fine particles, the refractive index may be lowered.

The water content in the modified zirconia fine particles is preferably 5% by weight or less, more preferably 2% by weight or less as H ₂ O.
When the content of water in the modified zirconia fine particles is large as H ₂ O, the fluidity of the modified zirconia fine particle powder is lowered and the dispersibility in an organic solvent and / or organic resin becomes insufficient. The dispersion dispersed in (2) has low transparency and may easily settle, resulting in insufficient stability of the dispersion. In addition, a film formed using a dispersion dispersed in an organic resin may have insufficient transparency and film strength. The water content in the modified zirconia fine particles is measured by collecting 0.15 g of the modified zirconia fine particles and using a Karl Fischer moisture meter (MKA-610) manufactured by Kyoto Electronics Industry Co., Ltd. The water content can be adjusted to a predetermined range or less by drying.

The average particle diameter (D _M2 ) of the modified zirconia fine particles according to the present invention is preferably in the range of 5 to 500 nm, more preferably 7 to 400 nm. When the average particle size is within this range, there is little aggregation, high fluidity, and high dispersibility in organic solvents and / or organic resins. For this reason, when a transparent film is formed, light scattering is small and haze is also low. If it exceeds the above range, it is difficult to obtain, and if it exceeds the above range, there are limitations on the use.For example, when used for forming a transparent film, light scattering becomes strong and the transparency is insufficient. Or haze may be high.

The average particle size (D _MZ ) of the modified zirconia fine particles was determined by dispersing the modified zirconia fine particle powder in methanol and preparing a dispersion having a solid content concentration of 30% by weight irradiated with ultrasonic waves. It measures with a measuring apparatus (Otsuka Electronics Co., Ltd. product: ELS-Z).

The average particle diameter (D _Z ) of the zirconia fine particles (before modification) used in the present invention is preferably in the range of 5 to 400 nm, more preferably 7 to 300 nm. If the average particle diameter (D _Z ) is in this range, the average particle diameter (D _M2 ) of the modified zirconia fine particles described above is achieved. When the average particle diameter (D _Z ) of the zirconia fine particles is less than the above range, it is difficult to obtain as non-aggregated fine particles, and when the excessively agglomerated particles are used, the fluidity and dispersibility of the present application are excellent. It is difficult to obtain modified zirconia fine particle powder. If the average particle diameter (D _Z ) of the zirconia fine particles exceeds the above range, the average particle diameter of the resulting modified zirconia fine particles may exceed a predetermined range, and as described above, there are restrictions on the use.

The average particle diameter (D _Z ) of the zirconia fine particles was determined by dispersing the unmodified zirconia fine particles in water and preparing a dispersion having a solid content concentration of 10% by weight irradiated with ultrasonic waves. Measured with ELS-Z).

Next, the ratio (D _M2 ) / (D _Z ) of the average particle size (D _Z ) of the zirconia fine particles to the average particle size (D _M2 ) of the modified zirconia fine particles is 0.2-5, and further 0 Preferably it is in the range of 5-3.

If the ratio (D _M2 ) / (D _Z ) is too large, it indicates that the degree of aggregation of the modified zirconia fine particles is high, and the dispersibility in an organic solvent and / or organic resin may be insufficient. May have low transparency and insufficient dispersion stability. Particles before modification may be aggregated, and aggregation may be loosened by modification, so (D _M2 ) / (D _Z ) may be less than 1. When (D _M2 ) / (D _Z ) is too low, this means that the raw material particles are excessively aggregated, and the modification is not uniform. Dispersibility may be insufficient.

In the case of modified zirconia that has been conventionally proposed, the powder is agglomerated when processed and has poor dispersibility. Therefore, the angle of repose (fluidity) cannot be evaluated.
Although the angle of repose of the modified zirconia fine particle powder according to the present invention varies depending on the average particle size of the modified zirconia fine particle, the angle of repose increases as the average particle size of the modified zirconia fine particle decreases, and the angle of repose increases as the average particle size increases. Although the angle tends to be low, it is preferably 45 ° or less, more preferably 40 ° or less. The modified zirconia fine particles of the present invention having such an angle of repose have high fluidity and high mixing and dispersibility with a viscous dispersion, so that a uniform dispersion can be obtained. A modified zirconia fine particle powder having a high angle of repose has low fluidity, low mixing property and dispersibility with a viscous dispersion such as a resin, and a uniform dispersion may not be obtained. In addition, when the modified zirconia fine particles are strongly aggregated, when the angle of repose is high and dispersed in an organic solvent and / or organic resin, the aggregated modified zirconia fine particles may remain and may not be uniformly monodispersed. is there.

  The modified zirconia fine particles constituting the modified zirconia fine particle powder according to the present invention are preferably crystalline. Specifically, a monoclinic crystal shape or a cubic crystal shape is preferable. If the modified zirconia fine particles are amorphous, fluidity, dispersibility, and the like may be insufficient. The reason for this is not necessarily clear, but the amorphous zirconia fine particles have many fine pores, and therefore the hydroxyl group or surface that cannot be bonded to the organosilicon compound due to steric hindrance remains, or the modified zirconia fine particle powder is an organic solvent. And / or dispersibility in the organic resin dispersion medium may be insufficient. When the modified zirconia fine particles are crystalline, the modified zirconia fine particle powder is excellent in fluidity, dispersibility, etc., and has a relatively high refractive index, and is useful as a high refractive index material.

  Such a modified zirconia fine particle according to the present invention is obtained by adding an organosilicon compound represented by the above formula (1) to water and / or an organic solvent dispersion of zirconia fine particles, thereby providing a hydrolysis catalyst for the organosilicon compound. It was prepared by drying under reduced pressure or flow, and further at 200 ° C. or lower without adding or replacing the solvent. Specifically, it is manufactured as follows.

[Production Method of Modified Zirconia Fine Particle Powder]
The method for producing modified zirconia fine particle powder according to the present invention is characterized by comprising the following steps (d) to (f).
(D) Step for preparing water and / or organic solvent dispersion of zirconia fine particles (e) Step for adding organosilicon compound represented by formula (1) (f) Without adding hydrolysis catalyst for organosilicon compound Without solvent replacement
Drying process

Step (d)
A water and / or organic solvent dispersion of zirconia fine particles is prepared.
(Zirconia fine particles)
As the zirconia fine particles, zirconia fine particles having an average particle diameter of the obtained modified zirconia fine particles in the range of approximately 5 to 400 nm, preferably approximately 7 to 300 nm, are used. Specifically, the average particle diameter (D _Z ) is preferably in the range of 5 to 400 nm, more preferably 7 to 300 nm. When the average particle diameter (D _Z ) is within this range, the average particle diameter (D _MZ ) of the modified zirconia fine particles described above is achieved.
At this time, as the zirconia fine particles, it is preferable to use crystalline zirconia fine particles for the reasons described above.

Method for Preparing Zirconia Fine Particles In the present invention, such zirconia fine particles are subjected to (a) zirconium hydroxide gel peptization or dissolution in the presence of potassium hydroxide and hydrogen peroxide, and (b) hydrothermal treatment. (C) What was obtained by washing is preferred.

  First, a zirconium hydroxide gel is peptized or dissolved in the presence of potassium hydroxide and hydrogen peroxide. The zirconium hydroxide gel is not particularly limited as long as it can be peptized or dissolved in the presence of potassium hydroxide and hydrogen peroxide. For example, a zirconium hydroxide gel obtained by hydrolyzing or neutralizing a zirconium compound (zirconia) Hydrate, zirconium hydroxide, etc.) can be used.

Zirconium compounds include zirconium chloride (ZrCl ₂ ), zirconium oxychloride (ZrOCl ₂ ), zirconium nitrate, zirconyl nitrate, zirconium sulfate, zirconium carbonate, zirconium acetate, and the like, as well as zirconium alkoxides.

  In addition, when adjusting a zirconium hydroxide gel and mixed zirconium hydroxide gel, in order to adjust the magnitude | size etc. of a gel, you may use the same particle growth regulator mentioned later. Said zirconium hydroxide gel and mixed zirconium hydroxide gel can be prepared according to Japanese Patent Application Laid-Open No. 2009-167085 filed by the present applicant.

  Potassium hydroxide and hydrogen peroxide are added to the zirconium hydroxide gel dispersion described above. At this time, the concentration of the zirconium hydroxide gel dispersion is preferably adjusted to a range of 0.1 to 20% by weight, further 0.2 to 15% by weight, particularly 0.5 to 10% by weight as a solid content. . Within this concentration range, production efficiency is high and the particle size distribution is uniform. If the dispersion concentration is too low, the yield and production efficiency may decrease. If it is too high, the particle size distribution of the finally obtained modified zirconia fine particles tends to be non-uniform.

The number of moles of zirconium hydroxide gel as ZrO ₂ is (M _Zr ), the number of moles of alkali metal hydroxide is (M _OH ), and the number of moles of hydrogen peroxide as H ₂ O ₂ is (M _PO ), (M _OH ) / (M _Zr ) is in the range of 1-20, more preferably in the range of 2-15, and (M _PO ) / (M _Zr ) is in the range of 5-30, more preferably 8-25. It is preferable to be in the range.

If (M _OH ) / (M _Zr ) is small, the zirconium hydroxide gel is not sufficiently dissolved, and the average particle size is small, and modified zirconia-based fine particles having a uniform particle size distribution may not be obtained. Even if (M _OH ) / (M _Zr ) is too large, the dissolution of the zirconium hydroxide gel does not increase, the uniformity of the particle diameter of the resulting zirconia fine particles is not improved, and the subsequent steps This increases the burden of removing and cleaning the alkali, which is not economical.

Temperature for peptization or dissolving, the _{(M OH) / (M Zr} ), varies depending _{(M PO) / (M Zr} ), 0~90 ℃, more in the range of 5 to 80 ° C. It is preferable. When the temperature is within this range, peptization (dissolution) is sufficiently performed, the stability of the dissolution solution is increased, and the economy is excellent.

The peptization or dissolution time is not particularly limited as long as the zirconium hydroxide gel is peptized or dissolved, but 5 hours is usually sufficient.
Note that peptization usually means that the zirconium hydroxide gel, which is an aggregate of fine zirconium hydroxide gel, is made fine by eliminating the aggregation state, and may be partially dissolved. Dissolution is to dissolve them.

  Hydrothermal treatment can be performed without necessarily undergoing peptization or dissolution. However, when hydrothermal treatment is carried out in advance, the particle size distribution is narrow, uniform, highly dispersible, and has a high refractive index. This is preferable in that modified zirconia-based fine particles can be obtained.

Next, the zirconium hydroxide gel peptization or dissolution solution is hydrothermally treated.
In the zirconium hydroxide gel peptization or dissolution solution, it is preferable to add a basic nitrogen compound to increase the pH of the solution as high as possible in the range of 9 to 14, more preferably 11 to 14.

Examples of the basic nitrogen compound include NH ₃ , tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), and tetrabutylammonium hydroxide (TBAH). When the pH of the dissolved solution is adjusted to the above range, modified zirconia-based fine particles having high crystallinity and high refractive index can be obtained.

  The hydrothermal treatment is preferably performed in the presence of a particle growth regulator. As the particle growth regulator, carboxylic acid or carboxylate, hydroxycarboxylic acid (having a carboxyl group and an alcoholic hydroxyl group in one molecule), hydroxycarboxylate and the like are used.

  Specifically, tartaric acid, formic acid, acetic acid, succinic acid, acrylic acid (unsaturated carboxylic acid), monocarboxylic acid and monocarboxylic acid salt such as gluconic acid, malic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, Examples thereof include polyvalent carboxylic acids such as adipic acid, sebacic acid, maleic acid, fumaric acid, and phthalic acid, and polyvalent carboxylates. Further, α-lactic acid, β-lactic acid, γ-hydroxyvaleric acid, glyceric acid, tartaric acid, citric acid, tropic acid, hydroxycarboxylic acid and hydroxycarboxylate of benzylic acid can be mentioned.

The amount of the grain growth regulator used is preferably 0.1 to 20 moles, more preferably 1 to 8 moles, based on 1 mole of ZrO ₂ in the peptizing (dissolving) solution. When the amount of the particle growth regulator used is in such a range, the particle size distribution of the finally obtained zirconia sol becomes uniform and can be adjusted to a predetermined average particle size.

  The hydrothermal treatment temperature is preferably in the range of 40 to 300 ° C, more preferably 100 to 250 ° C. If the hydrothermal treatment temperature is within this range, zirconia particles having high crystallinity and a uniform particle size distribution can be efficiently obtained.

  The hydrothermal treatment time is not particularly limited and is usually 0.5 to 12 hours although it varies depending on the hydrothermal treatment temperature. By performing hydrothermal treatment in this manner, zirconia fine particles having a uniform particle size distribution and non-aggregated can be produced.

  In addition, when the zirconia fine particles are aggregated, a dispersion treatment can be performed as necessary. Further, a dispersion accelerator may be added during the dispersion treatment. As a method for the dispersion treatment, a conventionally known apparatus such as a ball mill, a jet mill, or a roll rolling mill can be used.

  As the dispersion accelerator, an aqueous solution of an alkali metal hydroxide such as NaOH or KOH can be usually used. Moreover, basic compounds, such as ammonia and an organic amine, can be used.

  Thereafter, the zirconia fine particle dispersion is washed. As washing methods, potassium ion of potassium hydroxide used in the step (a), particle growth regulator used in the step (b), dispersion accelerator used if necessary, other cations, anions In addition, there is no particular limitation as long as the salt can be removed, and a conventionally known method can be employed. Examples thereof include an ultrafiltration membrane method, a filtration separation method, a centrifugal filtration method, an ion exchange resin method, and an electrodialysis method. It is done.

  Among them, the ultrafiltration membrane method and the electrodialysis method are preferably employed because they can remove impurities without greatly changing the pH of the solution, and thus do not impair the stability and dispersibility of the zirconia fine particles. be able to.

  The zirconia fine particle dispersion is preferably washed with a dispersion having a solid concentration of 10% by weight until the electric conductivity is 3 mS / cm or less, more preferably 0.3 mS / cm or less. If the conductivity of the dispersion is within the above range, the remaining amount of impurities such as ionic components can be 5% by weight or less, further 0.5% by weight or less based on the weight of the zirconia fine particles.

  When the impurities such as ionic components are washed and reduced in this way, the reason is not necessarily clear, but the adsorbed ions on the zirconia surface are removed, and the reaction with the organosilicon compound becomes efficient, or the particles The effect of improving the dispersibility of the resulting modified zirconia fine particle powder in various organic solvents can be obtained because the electric double layer on the surface becomes thicker and the electrostatic repulsive force acting between the zirconia fine particles increases.

(water)
The total amount of water can be used as the dispersion medium. However, when used in a mixture with an organic solvent, the amount of water used may be more than the amount capable of hydrolyzing the hydrolyzable group of the organosilicon compound to be used.

(Organic solvent)
The organic solvent is compatible with water and is not particularly limited as long as the organosilicon compound dissolves. However, methanol, ethanol, propanol, 2-propanol (IPA), butanol, diacetone alcohol, furfuryl alcohol, Alcohols such as tetrahydrofurfuryl alcohol, ethylene glycol, hexylene glycol, and isopropyl glycol; esters such as methyl acetate, ethyl acetate, and butyl acetate; diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol Ethers such as monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether; acetone, Methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, ketones such as acetoacetate, methyl cellosolve, ethyl cellosolve, butyl cellosolve, toluene, cyclohexanone, isophorone and the like.

Among them, alcohols having a low boiling point can be suitably used because they can be dried and removed at a low temperature in the step (f) described later.
The concentration of the zirconia fine particles in water and / or the organic solvent dispersion is not particularly limited, but is preferably in the range of about 1 to 30% by weight as the solid content.
The dispersion is preferably subjected to a dispersion treatment. As a dispersion treatment method, a method such as sufficient stirring and irradiation with ultrasonic waves can be employed.

Step (e)
An organosilicon compound represented by the following formula (1) is added.
_{R n -SiX 4-n (1} )
(In the formula, R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, and may be the same or different from each other. X: an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, Halogen, hydrogen, n: an integer of 1 to 3)

As the organosilicon compound, the aforementioned organosilicon compound is used.
In addition, when only water is used as the dispersion medium in the step (d), or when the organic solvent is small, it may be added as an organic solvent solution of the organosilicon compound in the present step (e). Organosilicon compounds, organosilicon compound amount in the resulting modified zirconia particles _{R n -SiO (4-n)} / 2 1~50 wt% (n is an integer of 1 to 3) As a further 2 to 40 It is preferable to add so that it may become the range of weight%.

  If the amount of the organosilicon compound used is small, it may vary depending on the type of the organosilicon compound and the average particle size of the zirconia fine particles, but a strongly agglomerated modified zirconia fine particle powder may be obtained. Even when dispersed in an organic resin or the like, it may not be possible to obtain a uniformly monodispersed dispersion. If the amount of the organosilicon compound used is too large, for example, the unreacted organosilicon compound and the reaction product between the organosilicon compounds will increase, and the fluidity of the modified zirconia fine particle powder, the dispersibility in the organic solvent and / or the organic resin will be increased. In addition, the effect of further improvement may not be obtained. In addition, depending on the application of the modified zirconia fine particles, the refractive index may be lowered.

Step (f)
Then dry. In the present invention, drying is performed without adding a catalyst for hydrolysis of the organosilicon compound and without replacing the solvent.

Drying is preferably performed at 200 ° C. or lower under reduced pressure or under flowing conditions.
When a catalyst is added or solvent substitution is performed, the organosilicon compound is hydrolyzed and surface treatment is performed on the OH groups on the particle surface, so the half-width of the main peak of the ²⁹ Si MAS NMR spectrum is 3 The peak becomes sharper than the range of ˜15 ppm, and as described above, the stability of the dispersion may be lowered, and the dispersibility of the powder may be lowered. Drying is preferably performed under reduced pressure or under fluidized conditions.

  As in the present invention, when the catalyst is not added, the solvent is not replaced, and drying is performed under reduced pressure or under fluid conditions, polycondensation between the organosilicon compounds proceeds during the surface treatment, and the particle surface Interaction between OH group and hydrophilic component is strengthened.

  As a method of drying under flow, a rotary dryer such as a rotary evaporator is used. When using a tumble dryer, the modified zirconia fine particles do not agglomerate strongly, and a modified zirconia fine particle powder weakly agglomerated in granular form is obtained. System fine particle powder can be obtained.

  When dried under reduced pressure, the solvent can be removed at a lower temperature, and the modified zirconia fine particle powder can be easily monodispersed even if the OH group on the surface of the zirconia fine particles and the organosilicon compound are bonded without agglomeration of the zirconia fine particles. Can be obtained.

The water content in the modified zirconia fine particles after drying is preferably 5% by weight or less, more preferably 2% by weight or less as H ₂ O. If the amount of water is large, the content of the organosilicon compound tends to decrease, and the bond between the modified zirconia fine particles becomes strong, so that the fluidity and dispersibility may be lowered.

  Here, “under reduced pressure” may be lower than normal pressure (atmospheric pressure). In the present invention, it is preferably about 800 hPa or less, more preferably 500 hPa or less. At this time, the pressure does not need to be constant, and the pressure can be gradually reduced.

  The drying temperature varies depending on the boiling point of the solvent, the drying method, and the like, but may be any temperature at which the solvent is volatilized, and is preferably 200 ° C. or lower. More preferably, it is in the range of -30 to 150 ° C, more preferably 0 to 120 ° C.

  If the drying temperature is too high, the moisture content of the resulting modified zirconia fine particle powder is reduced, but the modified zirconia fine particles may be strongly aggregated or the fluidity and dispersibility may be insufficient.

The drying temperature does not need to be constant. For example, the drying can be performed at a low temperature until water and / or the organic solvent can be substantially removed, and then the drying can be performed at a high temperature within the above range.
The modified zirconia fine particle powder thus obtained has an average secondary particle size (D _M2 ) in the range of 5 to 500 nm and an average primary particle size (D _M1 ) in the range of 5 to 500 nm as described above. the ratio of the average primary particle diameter and the average secondary particle diameter _{(D M2) (D M1)} (D M2) / (D M1) is in the 1 to 10.
The ratio (D _M2 ) / (D _Z ) between the average particle size (D _Z ) of the zirconia fine particles and the average particle size (D _M2 ) of the modified zirconia fine particles is 0.2 to 5.

[Modified zirconia fine particle dispersion]
The modified zirconia fine particle dispersion according to the present invention is obtained by dispersing the modified zirconia fine particle powder in an organic solvent and / or an organic resin.

As the organic solvent , a conventionally known organic solvent can be used.
Specifically, alcohols such as methanol, ethanol, propanol, 2-propanol (IPA), butanol, diacetone alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, hexylene glycol, isopropyl glycol; methyl acetate , Esters such as ethyl acetate, butyl acetate; ethers such as diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether; acetone , Methyl ethyl ketone, methyl isobutyl ketone, acetyl acetone, aceto vinegar Ketones such as esters, methyl cellosolve, ethyl cellosolve, butyl cellosolve, toluene, cyclohexanone, isophorone and the like and mixed solvents thereof.

As the organic resin , a conventionally known organic resin can be used.
Specific examples include known thermosetting resins, thermoplastic resins, electron beam curable resins, and the like as coating resins. Examples of such resins include conventionally used thermoplastic resins such as polyester resins, polycarbonate resins, polyamide resins, polyphenylene oxide resins, thermoplastic acrylic resins, vinyl chloride resins, fluororesins, vinyl acetate resins, and silicone rubbers. , Urethane resin, melamine resin, silicon resin, butyral resin, reactive silicone resin, phenol resin, epoxy resin, unsaturated polyester resin, thermosetting acrylic resin, UV curable acrylic resin, etc., UV curable type An acrylic resin etc. are mentioned. Further, it may be a copolymer or modified body of two or more of these resins.

In the case of an ultraviolet curable resin, a photopolymerization initiator may be included, and in the case of a thermosetting resin, a curing catalyst may be included.
The modified zirconia fine particle dispersion (sol) according to the present invention is prepared by dispersing the modified zirconia fine particle powder in an organic solvent and / or an organic resin.

  There is no restriction | limiting in particular as a method to disperse | distribute, What is necessary is just to mix with an organic solvent and / or organic resin, and to stir, or to mix with stirring. Further, although it depends on the kind of the dispersion medium or the concentration of the obtained dispersion, means for promoting dispersion such as irradiation with ultrasonic waves can be taken as necessary.

  When the modified zirconia fine particle powder of the present invention is dispersed in the organic solvent, even if the concentration of the modified zirconia fine particles is high, the organic solvent of the modified zirconia fine particles is easily and uniformly dispersed and has excellent transparency and stability. A dispersed sol is obtained. In addition, when the modified zirconia fine particle powder of the present invention is dispersed in an organic resin, even when the concentration of the modified zirconia fine particles is increased without applying mechanical energy strongly, the organic particles dispersed uniformly can be easily dispersed. A resin dispersion of modified zirconia fine particles without a solvent is obtained.

  When a transparent coating is formed using a resin dispersion of modified zirconia fine particles that does not contain an organic solvent, a transparent coating cured by heating or ultraviolet irradiation can be formed without removing the solvent by drying. .

  The modified zirconia fine particle powder of the present invention does not have strong aggregation or bonding between the modified zirconia fine particles, and is excellent in fluidity and dispersibility, so that the modified zirconia fine particles are uniformly monodispersed without using mechanochemical means. A dispersion can be obtained.

The concentration of the modified zirconia fine particles in the organic solvent and / or the organic resin dispersion of the modified zirconia fine particles thus obtained is not particularly limited and is appropriately selected depending on the application. Usually, the solid content is preferably 1 to 70% by weight, more preferably 2 to 60% by weight.
The organic solvent or organic resin dispersion of the modified zirconia fine particles is a stable sol having transparency without allowing the modified zirconia fine particles to agglomerate or settle even when left for a long period of time.

[Example]
Hereinafter, although an example explains, the present invention is not limited by these examples.

[Example 1]
Preparation of modified zirconia fine particles (1) powder 317.9 kg of zirconia hydroxide gel having a solid content concentration of 9.5 wt% was suspended in 535.3 kg of water, and zirconia hydroxide having a solid content concentration of 3.5 wt% was suspended. A gel dispersion was prepared.

Next, 354.9 kg of KOH aqueous solution of 17% by weight, 302.0 kg of hydrogen peroxide aqueous solution of 35% by weight, and tartaric acid of 10% by weight of the zirconia hydroxide gel dispersion having a solid content of 3.5% by weight. 88.5 kg of an aqueous solution was added, and the mixture was stirred at 30 ° C. for 2 hours with stirring to peptize the zirconia hydroxide gel. Step (a)

At this time, (M _OH ) / (M _Zr ) was 20, and (M _PO ) / (M _Zr ) was 10.
Subsequently, 88.5 kg of a 10% by weight aqueous tartaric acid solution was added to the peptized zirconia hydroxide gel, and hydrothermally treated at 150 ° C. for 11 hours in an autoclave. Step (b)

Next, the zirconia fine particle dispersion was thoroughly washed by the ultrafiltration membrane method, and then dispersed with an ultrasonic homogenizer (manufactured by Nippon Seiki Seisakusho: US-600TCVP) to give a zirconia solid content of 11.2% by weight. A fine particle (1) dispersion was prepared. Step (c)

The average particle size of the zirconia fine particles (1) was measured with a particle size measuring device (manufactured by Otsuka Electronics Co., Ltd .: ELS-Z), and the results are shown in Table 1.
Next, 400 g of the zirconia fine particle (1) dispersion was collected in a beaker. Subsequently, 400 g of methanol was added to prepare a zirconia-based fine particle (1) water / methanol dispersion having a solid content concentration of 5.6% by weight. Step (d)

At this time, the ratio of methanol in the water / methanol mixed dispersion medium is 56% by weight.
Next, zirconia fine particles (1) γ-methacrylooxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503) as an organic silicon compound in a water / methanol dispersion, and organics in the resulting modified zirconia fine particles silicon compound was added 11.2g such that 15.3% by weight R ₁ -SiO _3/2, and stirred for 5 minutes. Step (e)

Subsequently, the zirconia fine particle (1) powder was prepared by drying at 60 ° C. for 1.5 hours while gradually decreasing the degree of pressure reduction to 50 hPa or less with a rotary evaporator. Step (f)

The resulting modified zirconia fine particle (1) powder was measured for water content, crystallinity, average particle diameter, angle of repose, and refractive index, and the results are shown in Table 1. Here, the average particle diameter is an average particle diameter measured with a modified zirconia fine particle (1) methanol dispersion described later.
The water content, angle of repose and refractive index were measured by the following methods.

Water content Kyoto Electronics Industry Co., Ltd .: The water content of the modified zirconia fine particles (1) powder was measured with a Karl Fischer moisture meter (MKA-610), and the results are shown in Table 1.

Fill a transparent sample bottle made of angle of repose glass (cylindrical, internal volume 100 cc) with about 30 cc of modified zirconia fine particles (1) powder, rotate the surface of the horizontal plate about 10 times at a low speed, and then adjust the angle of the upper surface of the powder. Measurement was performed with a protractor, and the results are shown in Table 1.

Refractive index In the present invention, the refractive index was measured by the following method using Series A and AA manufactured by CARGILL as the standard refractive liquid, and the results are shown in Table 1.
(1) Modified zirconia fine particles (1) Take the dispersion liquid in an evaporator and evaporate the dispersion medium.
(2) This is dried at 80 ° C. for 12 hours to obtain a powder.
(3) A standard refraction liquid having a known refractive index is dropped on a glass plate of a few drops, and the above powder is mixed therewith.
(4) Perform the above operation (3) with various standard refractive liquids, and use the refractive index of the standard refractive liquid when the mixed liquid becomes transparent as the refractive index of the modified zirconia fine particles (1).

²⁹ Si MAS NMR spectra also modified zirconia fine particles (1) Nuclear magnetic resonance apparatus ²⁹ Si MAS NMR spectrum for the powder (Agilent technologies Inc.: VNMRS-600) was used for the measurement. Polydimethylsilane (−34.44 ppm) was used as a standard substance, and measurement was performed by a single pulse method under conditions of a delay time of 15 seconds and a MAS speed of 6 kHz. The chemical shift value and half-value width of the main peak analyzed by the curve fitting program attached to the apparatus are shown in the table.

Modified zirconia fine particles (1) Preparation of organic solvent dispersion Modified zirconia fine particles (1) 5 g of powder was mixed with methanol and methyl isobutyl ketone, stirred well, and modified zirconia fine particles (1) with a solid content concentration of 30% by weight. Methanol dispersion and modified zirconia fine particles (1) methyl isobutyl ketone dispersion were prepared.

The average particle diameter of the obtained modified zirconia fine particles (1) methanol dispersion was measured, and the results are shown in Table 1.
In addition, the dispersibility and stability of the modified zirconia fine particles (1) methanol dispersion and the modified zirconia fine particles (1) methyl isobutyl ketone dispersion having a solid content concentration of 30% by weight were evaluated by the following methods, and the results are shown. It is shown in 1.

Dispersed glass transparent sample bottles were filled with the dispersion, observed for transparency, and evaluated according to the following criteria.
It is a transparent dispersion. : ◎
It is a highly transparent dispersion. : ○
A translucent dispersion. : △
It is a cloudy dispersion. : ×
The dispersion was filled in a transparent glass transparent sample bottle and allowed to stand at 30 ° C. for 10 days, and then the transparency was observed and evaluated according to the following criteria.
It is a transparent dispersion. : ◎
It is a highly transparent dispersion. : ○
A translucent dispersion. : △
It is a dispersion in which white turbidity or precipitated particles are observed. : ×

Modified zirconia fine particles (1) Preparation of organic resin dispersion Modified zirconia fine particles (1) 3 g of light acrylate DPE-6A (hereinafter simply DPE-6A) (Kyoeisha Chemical Co., Ltd. dipentaerythritol hexaacrylate, UV The mixture was mixed with a curable acrylic resin (polyvalent acrylic monomer) and sufficiently stirred to prepare a modified zirconia fine particle (1) organic resin dispersion having a solid content concentration of 30% by weight.
About the obtained modified zirconia fine particle (1) organic resin dispersion, dispersibility was evaluated by the following method, and the results are shown in Table 1.

Dispersion glass transparent sample bottles were filled into the dispersion, observed for transparency, and evaluated according to the following criteria.
It is a transparent dispersion. : ◎
It is a highly transparent dispersion. : ○
A translucent dispersion. : △
It is a cloudy dispersion. : ×

[Example 2]
Preparation of Modified Zirconia Fine Particle (2) Powder A modified zirconia fine particle (2) powder was prepared in the same manner as in Example 1 except that it was dried at 40 for 24 hours. Step (f)
The resulting modified zirconia fine particle (2) powder was measured for water content, crystallinity, average particle size, angle of repose, and refractive index, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of Modified Zirconia Fine Particles (2) Organic Solvent Dispersion In Example 1, modified zirconia fine particles having a solid content concentration of 30% by weight (2) Methanol dispersion were the same except that modified zirconia fine particles (2) were used. And modified zirconia fine particles (2) MIBK dispersion was prepared.

The average particle diameter of the obtained modified zirconia fine particles (2) methanol dispersion was measured, and the results are shown in Table 1.
Further, the dispersibility and stability of the modified zirconia fine particles (2) methanol dispersion and the modified zirconia fine particles (2) methyl isobutyl ketone dispersion having a solid content concentration of 30% by weight were evaluated, and the results are shown in Table 1.

Preparation of Modified Zirconia Fine Particles (2) Organic Resin Dispersion Modified zirconia fine particles (2) organic resin having a solid content concentration of 30% by weight in the same manner as in Example 1, except that the modified zirconia fine particles (2) powder was used. A dispersion was prepared.
The resulting modified zirconia fine particles (2) organic resin dispersion was evaluated for dispersibility, and the results are shown in Table 1.

[Example 3]
Preparation of Modified Zirconia Fine Particle (3) Powder A modified zirconia fine particle (3) powder was prepared in the same manner as in Example 1 except that it was dried at 80 ° C. for 1 h using a rotary evaporator. Step (f)
The resulting modified zirconia fine particle (3) powder was measured for water content, crystallinity, average particle diameter, angle of repose, and refractive index, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of Modified Zirconia Fine Particles (3) Organic Solvent Dispersion In Example 1, modified zirconia fine particles (3) methanol dispersion having a solid content concentration of 30% by weight was the same except that modified zirconia fine particles (3) powder was used. And modified zirconia fine particles (3) MIBK dispersion was prepared.

The average particle diameter of the resulting modified zirconia fine particles (3) methanol dispersion was measured, and the results are shown in Table 1.
Further, the dispersibility and stability of the modified zirconia fine particles (3) methanol dispersion and the modified zirconia fine particles (3) methyl isobutyl ketone dispersion having a solid content concentration of 30% by weight were evaluated, and the results are shown in Table 1.

Preparation of modified zirconia fine particles (3) organic resin dispersion Modified zirconia fine particles (3) organic resin having a solid content concentration of 30% by weight in the same manner as in Example 1, except that the modified zirconia fine particles (3) powder was used. A dispersion was prepared.
The resulting modified zirconia fine particles (3) organic resin dispersion was evaluated for dispersibility, and the results are shown in Table 1.

[Example 4]
Preparation of modified zirconia fine particles (4) powder In step (e) of Example 1, γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503) is obtained. Modified zirconia fine particles (4) powder was prepared in the same manner except that 9.0 g was added so that the organosilicon compound in the modified zirconia fine particles was 12.6% by weight as R ₁ —SiO _3/2 .

With respect to the obtained modified zirconia fine particle (4) powder, the water content, crystallinity, average particle diameter, angle of repose and refractive index were measured, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of Modified Zirconia Fine Particles (4) Organic Solvent Dispersion Modified zirconia fine particles (4) organic solvent having a solid content concentration of 30% by weight in the same manner as in Example 1 except that the modified zirconia fine particles (4) powder was used. A dispersion was prepared.
With respect to the obtained modified zirconia fine particles (4) organic solvent dispersion, the particle diameter was measured, the stability and light transmittance (transparency) were evaluated by the following methods, and the results are shown in Table 1.

Preparation of Modified Zirconia Fine Particles (4) Organic Resin Dispersion Modified zirconia fine particles (4) organic resin having a solid concentration of 30% by weight in the same manner as in Example 1 except that the modified zirconia fine particles (4) powder was used. A dispersion was prepared.
With respect to the obtained modified zirconia fine particles (4) organic resin dispersion, the particle diameter was measured, the stability and light transmittance (transparency) were evaluated by the following methods, and the results are shown in Table 1.

[Example 5]
Preparation of Modified Zirconia Fine Particles (5) Powder In step (e) of Example 1, γ-methacrylooxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503) is obtained as modified zirconia fine particles. Modified zirconia fine particle (5) powder was prepared in the same manner except that 22.4 g was added so that the organic silicon compound contained therein was 36.1 wt% as R ₁ —SiO _3/2 .

The resulting modified zirconia fine particle (5) powder was measured for water content, crystallinity, average particle diameter, angle of repose, and refractive index, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of Modified Zirconia Fine Particles (5) Organic Solvent Dispersion Modified zirconia fine particles (5) organic solvent having a solid content concentration of 30% by weight in the same manner as in Example 1 except that modified zirconia fine particles (5) powder was used. A dispersion was prepared.
With respect to the obtained modified zirconia fine particles (5) organic solvent dispersion, the particle diameter was measured, and the stability and light transmittance (transparency) were evaluated by the following methods. The results are shown in Table 1.

Preparation of Modified Zirconia Fine Particles (5) Organic Resin Dispersion Modified zirconia fine particles (5) organic resin having a solid content concentration of 30% by weight in the same manner as in Example 1 except that modified zirconia fine particles (5) powder was used. A dispersion was prepared.
With respect to the obtained modified zirconia fine particles (5) organic resin dispersion, the particle diameter was measured, the stability and light transmittance (transparency) were evaluated by the following methods, and the results are shown in Table 1.

[Example 6]
Preparation of Modified Zirconia Fine Particle (6) Powder Modified zirconia fine particle (6) powder was prepared in the same manner as in Step (d) of Example 1, except that methanol was not added. Step (f)

The resulting modified zirconia fine particle (6) powder was measured for water content, crystallinity, average particle diameter, angle of repose, and refractive index, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table. Such a spectrum is shown in FIG.

Preparation of Modified Zirconia Fine Particles (6) Organic Solvent Dispersion Modified zirconia fine particles (6) organic solvent having a solid content concentration of 30% by weight in the same manner as in Example 1 except that the modified zirconia fine particles (6) powder was used. A dispersion was prepared.
With respect to the obtained modified zirconia fine particles (6) organic solvent dispersion, the particle diameter was measured, and the stability and light transmittance (transparency) were evaluated by the following methods. The results are shown in Table 1.

Preparation of Modified Zirconia Fine Particle (6) Organic Resin Dispersion Modified zirconia fine particle (6) organic resin having a solid content concentration of 30% by weight in the same manner as in Example 1 except that the modified zirconia fine particle (6) powder was used. A dispersion was prepared.
With respect to the obtained modified zirconia fine particle (6) organic resin dispersion, the particle diameter was measured, the stability and light transmittance (transparency) were evaluated by the following methods, and the results are shown in Table 1.

[Example 7]
Preparation of modified zirconia fine particle (7) powder Modified zirconia fine particle (7) powder was prepared in the same manner as in step (d) of Example 1, except that isopropyl alcohol (IPA) was added instead of methanol.
With respect to the obtained modified zirconia fine particle (7) powder, the water content, crystallinity, average particle diameter, angle of repose and refractive index were measured, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of Modified Zirconia Fine Particles (7) Organic Solvent Dispersion Modified zirconia fine particles (7) organic solvent having a solid content concentration of 30% by weight in the same manner as in Example 1 except that the modified zirconia fine particles (7) powder was used. A dispersion was prepared.
With respect to the obtained modified zirconia fine particles (7) organic solvent dispersion, the particle diameter was measured, the stability and light transmittance (transparency) were evaluated by the following methods, and the results are shown in Table 1.

Preparation of Modified Zirconia Fine Particles (7) Organic Resin Dispersion Modified zirconia fine particles (7) organic resin having a solid content concentration of 30% by weight in the same manner as in Example 1 except that modified zirconia fine particles (7) powder was used. A dispersion was prepared.
The resulting modified zirconia fine particle (7) organic resin dispersion was measured for particle size, and the stability and light transmittance (transparency) were evaluated by the following methods. The results are shown in Table 1.

[Example 8]
Preparation of modified zirconia fine particles (8) powder Modified zirconia fine particles (8) powder in the same manner as in step (b) of Example 8, except that 531 kg of tartaric acid was added to the solution obtained by peptizing zirconia hydroxide gel. Was prepared.
The resulting modified zirconia fine particle (8) powder was measured for water content, crystallinity, average particle diameter, angle of repose, and refractive index, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of Modified Zirconia Fine Particle (8) Organic Solvent Dispersion In Example 1, modified zirconia fine particles (8) organic solvent having a solid content concentration of 30% by weight were used except that modified zirconia fine particles (8) powder was used. A dispersion was prepared.
With respect to the obtained modified zirconia fine particles (8) organic solvent dispersion, the particle diameter was measured, the stability and light transmittance (transparency) were evaluated by the following methods, and the results are shown in Table 1.

Preparation of Modified Zirconia Fine Particle (8) Organic Resin Dispersion Modified zirconia fine particle (8) organic resin having a solid content concentration of 30% by weight in the same manner as in Example 1 except that the modified zirconia fine particle (8) powder was used. A dispersion was prepared.
The resulting modified zirconia fine particle (8) organic resin dispersion was measured for particle size and evaluated for stability and light transmittance (transparency) by the following methods. The results are shown in Table 1.

[Example 9]
Preparation of Modified Zirconia Fine Particle (9) Powder Modified zirconia fine particle (9) powder was prepared in the same manner as in Step (b) of Example 1, except that hydrothermal treatment was performed at 110 ° C. for 36 hours.
With respect to the obtained modified zirconia fine particle (9) powder, the water content, crystallinity, average particle diameter, angle of repose, and refractive index were measured, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of Modified Zirconia Fine Particles (9) Organic Solvent Dispersion In Example 1, modified zirconia fine particles (9) organic solvent having a solid content concentration of 30% by weight were used except that the modified zirconia fine particles (9) powder was used. A dispersion was prepared.
The resulting modified zirconia fine particle (9) organic solvent dispersion was measured for particle size, evaluated for stability and light transmittance (transparency) by the following methods, and the results are shown in Table 1.

Preparation of Modified Zirconia Fine Particles (9) Organic Resin Dispersion Modified zirconia fine particles (9) organic resin having a solid content concentration of 30% by weight in the same manner as in Example 1 except that modified zirconia fine particles (9) powder was used. A dispersion was prepared.
The resulting modified zirconia fine particle (9) organic resin dispersion was measured for particle size and evaluated for stability and light transmittance (transparency) by the following methods. The results are shown in Table 1.

[Example 10]
Preparation of Modified Zirconia Fine Particle (10) Powder Modified zirconia fine particle (10) powder was prepared in the same manner as in Step (b) of Example 1, except that hydrothermal treatment was performed at 180 ° C. for 3 hours.
The resulting modified zirconia fine particle (10) powder was measured for water content, crystallinity, average particle size, angle of repose, and refractive index, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of modified zirconia fine particles (10) organic solvent dispersion Modified zirconia fine particles (10) organic solvent having a solid content concentration of 30% by weight in the same manner as in Example 1, except that the modified zirconia fine particles (10) powder was used. A dispersion was prepared.
With respect to the obtained modified zirconia fine particle (10) organic solvent dispersion, the particle diameter was measured, and the stability and light transmittance (transparency) were evaluated by the following methods. The results are shown in Table 1.

Preparation of Modified Zirconia Fine Particles (10) Organic Resin Dispersion Modified zirconia fine particles (10) organic resin having a solid concentration of 30% by weight in the same manner as in Example 1, except that modified zirconia fine particles (10) powder was used. A dispersion was prepared.
The resulting modified zirconia fine particle (10) organic resin dispersion was measured for particle size and evaluated for stability and light transmittance (transparency) by the following methods. The results are shown in Table 1.

[Example 11]
Preparation of Modified Zirconia Fine Particle (11) Powder In step (e) of Example 1, γ-acrylo was used instead of γ-methacrylooxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503). 10. Oxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-5103) is used so that the organosilicon compound in the resulting modified zirconia fine particles is 15.0 wt% as R ₁ —SiO _3/2 . Modified zirconia fine particle (11) powder was prepared in the same manner except that 2 g was added.

The resulting modified zirconia fine particle (11) powder was measured for water content, crystallinity, average particle size, angle of repose, and refractive index, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of Modified Zirconia Fine Particle (11) Organic Solvent Dispersion In Example 1, modified zirconia fine particles (11) organic solvent having a solid content concentration of 30% by weight were used except that the modified zirconia fine particles (11) powder was used. A dispersion was prepared.
With respect to the obtained modified zirconia fine particle (11) organic solvent dispersion, the particle diameter was measured, the stability and light transmittance (transparency) were evaluated by the following methods, and the results are shown in Table 1.

Preparation of Modified Zirconia Fine Particles (11) Organic Resin Dispersion Modified Example Zirconia Fine Particles (11) Organic Resin having a solid content concentration of 30% by weight in the same manner as in Example 1 except that the modified zirconia fine particles (11) powder was used. A dispersion was prepared.
The resulting modified zirconia fine particle (11) organic resin dispersion was measured for particle size and evaluated for stability and light transmittance (transparency) by the following methods. The results are shown in Table 1.

[Example 12]
Preparation of modified zirconia fine particles (12) powder Instead of steps (a), (b) and (c) of Example 1, zirconia powder (first rare element) was dissolved in an aqueous solution of 26.8 g of tartaric acid in 368 g of pure water. 218 g of Chemical Industry Co., Ltd. (RC-100) was added, and then an aqueous KOH solution having a concentration of 10 wt% was added to obtain a zirconia powder dispersion having a pH of 12.3. This was dispersed with a disperser (manufactured by Campe Co., Ltd .: BATCH SAND), then washed with an ultrafiltration membrane until the conductivity reached about 300 μs / cm, and then an anion exchange resin (ROHM AND HAAS: DUOLITE UP5000) 240 g was added to perform washing treatment, and the resin was separated. This was treated as a zirconia fine particle dispersion (12) having a zirconia concentration of 11.2% by weight in the same manner as in Example 1 to prepare modified zirconia fine particles (12) powder. Step (f)

The resulting modified zirconia fine particle (12) powder was measured for water content, crystallinity, average particle diameter, angle of repose, and refractive index, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of modified zirconia fine particles (12) organic solvent dispersion Modified zirconia fine particles (12) organic solvent having a solid content concentration of 30% by weight in the same manner as in Example 1, except that the modified zirconia fine particles (12) powder was used. A dispersion was prepared.
The resulting modified zirconia fine particle (12) organic solvent dispersion was measured for particle size and evaluated for stability and light transmittance (transparency) by the following methods. The results are shown in Table 1.

Preparation of Modified Zirconia Fine Particles (12) Organic Resin Dispersion Modified zirconia fine particles (12) organic resin having a solid concentration of 30% by weight in the same manner as in Example 1 except that modified zirconia fine particles (12) powder was used. A dispersion was prepared.
The resulting modified zirconia fine particle (12) organic resin dispersion was measured for particle size and evaluated for stability and light transmittance (transparency) by the following methods. The results are shown in Table 1.

[Example 13]
Preparation of Modified Zirconia Fine Particles (13) Powder As in step 1 (e) of Example 1, zirconia fine particles (1) γ-methacrylooxypropyltrimethoxysilane (Shin-Etsu) as an organosilicon compound in a water / methanol dispersion. Chemical Co., Ltd. (KBM-503) was added in an amount of 11.2 g so that the organosilicon compound in the resulting modified zirconia fine particles was 15.3% by weight as R ₁ —SiO _3/2 and added for 5 minutes. Stir.

Subsequently, it was dried at 60 ° C. for 24 hours in a box dryer to prepare modified zirconia fine particle (13) powder.
With respect to the obtained modified zirconia fine particles (13), the water content, crystallinity, average particle diameter, angle of repose, and refractive index were measured, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of modified zirconia fine particles (13) organic solvent dispersion Modified zirconia fine particles (13) organic solvent having a solid content concentration of 30% by weight in the same manner as in Example 1 except that the modified zirconia fine particles (13) powder was used. A dispersion was prepared.

The average particle diameter of the obtained modified zirconia fine particles (13) methanol dispersion was measured, and the results are shown in Table 1.
The dispersibility and stability of the modified zirconia fine particles (13) methanol dispersion and the modified zirconia fine particles (13) methyl isobutyl ketone dispersion having a solid content concentration of 30% by weight were evaluated, and the results are shown in Table 1.

Preparation of Modified Zirconia Fine Particles (13) Organic Resin Dispersion Modified zirconia fine particles (13) organic resin having a solid content of 30% by weight in the same manner as in Example 1, except that modified zirconia fine particles (13) powder was used. A dispersion was prepared.
The obtained modified zirconia fine particle (13) organic resin dispersion was evaluated for dispersibility, and the results are shown in Table 1.

[Comparative Example 1]
Preparation of modified zirconia fine particles (R1) powder In the same manner as in Example 1, γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) as an organosilicon compound in a zirconia fine particles (1) water / methanol dispersion. : KBM-503) was added in an amount of 11.2 g so that the organosilicon compound in the resulting modified zirconia fine particles was 15.3% by weight as R ₁ —SiO _3/2 and stirred for 5 minutes. Step (e)

Subsequently, the solvent was replaced with methanol by an ultrafiltration membrane, and then dried by a box dryer at 60 ° C. for 24 hours to prepare modified zirconia fine particles (R1) powder.
In addition, when ammonia water was added to the filtrate at the time of ultrafiltration, it became cloudy and it was recognized that the unreacted organosilicon compound escaped.
The resulting modified zirconia fine particle (R1) powder was measured for water content, crystallinity, average particle size, angle of repose, and refractive index, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of Modified Zirconia Fine Particle (R1) Organic Solvent Dispersion In Example 1, the modified zirconia fine particle (R1) organic solvent having a solid concentration of 30% by weight was used except that the modified zirconia fine particle (R1) powder was used. A dispersion was prepared.
The average particle diameter of the obtained modified zirconia fine particle (R1) methanol dispersion was measured, and the results are shown in Table 1.
Further, the dispersibility and stability of the modified zirconia fine particle (R1) methanol dispersion and the modified zirconia fine particle (R1) methyl isobutyl ketone dispersion having a solid concentration of 30% by weight were evaluated, and the results are shown in Table 1.

Preparation of Modified Zirconia Fine Particle (R1) Organic Resin Dispersion In Example 1, modified zirconia fine particle (R1) organic resin having a solid content concentration of 30% by weight was used except that modified zirconia fine particle (R1) powder was used. A dispersion was prepared.
Dispersibility of the obtained modified zirconia fine particle (R1) organic resin dispersion was evaluated, and the results are shown in Table 1.

[Comparative Example 2]
Preparation of Modified Zirconia Fine Particles (R2) Powder Modified zirconia fine particles (R2) powder was prepared in the same manner as in Comparative Example 1, except that it was dried in a box dryer at 40 ° C. for 72 hours.
The resulting modified zirconia fine particle (R2) powder was measured for water content, crystallinity, average particle size, angle of repose, and refractive index, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of Modified Zirconia Fine Particle (R2) Organic Solvent Dispersion In Example 1, the modified zirconia fine particle (R2) organic solvent having a solid content concentration of 30% by weight was used except that the modified zirconia fine particle (R2) powder was used. A dispersion was prepared.
The average particle diameter of the resulting modified zirconia fine particle (R2) methanol dispersion was measured, and the results are shown in Table 1.
Further, the dispersibility and stability of the modified zirconia fine particle (R2) methanol dispersion and the modified zirconia fine particle (R2) methyl isobutyl ketone dispersion having a solid content concentration of 30% by weight were evaluated, and the results are shown in Table 1.

Preparation of Modified Zirconia Fine Particle (R2) Organic Resin Dispersion In Example 1, modified zirconia fine particle (R2) organic resin having a solid content of 30% by weight was used except that modified zirconia fine particle (R2) powder was used. A dispersion was prepared.
The resulting modified zirconia fine particle (R2) organic resin dispersion was evaluated for dispersibility, and the results are shown in Table 1.

[Comparative Example 3]
Preparation of modified zirconia fine particles (R3) powder Modified zirconia fine particles (R3) powder was prepared in the same manner as in Comparative Example 1, except that it was dried at 80 ° C. for 5 hours in a box dryer.
The resulting modified zirconia fine particle (R3) powder was measured for water content, crystallinity, average particle diameter, angle of repose, and refractive index, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of Modified Zirconia Fine Particle (R3) Organic Solvent Dispersion In Example 1, the modified zirconia fine particle (R3) organic solvent having a solid concentration of 30% by weight was used except that the modified zirconia fine particle (R3) powder was used. A dispersion was prepared.
The average particle diameter of the obtained modified zirconia fine particle (R3) methanol dispersion was measured, and the results are shown in Table 1.
Dispersibility and stability of the modified zirconia fine particle (R3) methanol dispersion and the modified zirconia fine particle (R3) methyl isobutyl ketone dispersion having a solid content concentration of 30% by weight were evaluated. The results are shown in Table 1.

Preparation of Modified Zirconia Fine Particle (R3) Organic Resin Dispersion Modified Example Zirconia Fine Particle (R3) Organic Resin with a Solid Concentration of 30% by Weight, except that Modified Zirconia Fine Particle (R3) Powder was used in Example 1. A dispersion was prepared.
The resulting modified zirconia fine particle (R3) organic resin dispersion was evaluated for dispersibility, and the results are shown in Table 1.

[Comparative Example 4]
Preparation of modified zirconia fine particles (R4) powder In the same manner as in Example 1, γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) as an organosilicon compound in a zirconia fine particle (1) water / methanol dispersion. : KBM-503) was added so that the organosilicon compound in the resulting modified zirconia fine particles was 15.3% by weight as R ₁ —SiO _3/2 , and then the dispersion was stirred. After raising the temperature to 60 ° C., 1.6 g of ammonia water having a concentration of 5% by weight was added in 1 minute to hydrolyze the organosilicon compound.

  Subsequently, the solvent was replaced with methanol by an ultrafiltration membrane, and then dried by a box dryer at 60 ° C. for 24 hours to prepare modified zirconia fine particles (R4) powder. In addition, when ammonia water was added to the filtrate at the time of ultrafiltration, white turbidity was not recognized.

The resulting modified zirconia fine particles (R4) powder was measured for water content, crystallinity, average particle diameter, angle of repose, and refractive index, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table. Moreover, the spectrum of ¹ H-NMR is shown in FIG.

Preparation of Modified Zirconia Fine Particles (R4) Organic Solvent Dispersion Modified Example Zirconia Fine Particles (R4) Organic Solvent having a solid content concentration of 30% by weight was the same as Example 1 except that modified zirconia fine particles (R4) powder was used. A dispersion was prepared.
The average particle diameter of the resulting modified zirconia fine particle (R4) methanol dispersion was measured, and the results are shown in Table 1.
Further, the dispersibility and stability of the modified zirconia fine particle (R4) methanol dispersion and the modified zirconia fine particle (R4) methyl isobutyl ketone dispersion having a solid content concentration of 30% by weight were evaluated, and the results are shown in Table 1.

Preparation of Modified Zirconia Fine Particle (R4) Organic Resin Dispersion In Example 1, modified zirconia fine particle (R4) organic resin having a solid concentration of 30% by weight was used except that modified zirconia fine particle (R4) powder was used. A dispersion was prepared.
The resulting modified zirconia fine particle (R4) organic resin dispersion was evaluated for dispersibility, and the results are shown in Table 1.

[Comparative Example 5]
Preparation of Modified Zirconia Fine Particles (R5) Powder In Comparative Example 4, the solvent was replaced with methanol using an ultrafiltration membrane, and then the rotary evaporator instead of the box dryer was used at 60 ° C. for 1.5 hours. Modified zirconia fine particles (R5) powder was prepared in the same manner except that it was dried while maintaining the pressure at 50 hPa.

The resulting modified zirconia fine particle (R5) powder was measured for water content, crystallinity, average particle size, angle of repose, and refractive index, and the results are shown in Table 1. In addition, the chemical shift value and half width of the main peak of the ²⁹ Si MAS NMR spectrum are shown in the table.

Preparation of Modified Zirconia Fine Particle (R5) Organic Solvent Dispersion In Example 1, modified zirconia fine particle (R5) organic solvent having a solid concentration of 30% by weight was used except that modified zirconia fine particle (R5) powder was used. A dispersion was prepared.

The average particle diameter of the obtained modified zirconia fine particle (R5) methanol dispersion was measured, and the results are shown in Table 1.
Further, the dispersibility and stability of the modified zirconia fine particle (R5) methanol dispersion and the modified zirconia fine particle (R5) methyl isobutyl ketone dispersion having a solid content concentration of 30% by weight were evaluated, and the results are shown in Table 1.

Preparation of Modified Zirconia Fine Particle (R5) Organic Resin Dispersion In Example 1, modified zirconia fine particle (R5) organic resin having a solid content of 30% by weight was used except that modified zirconia fine particle (R5) powder was used. A dispersion was prepared.
The resulting modified zirconia fine particle (R5) organic resin dispersion was evaluated for dispersibility, and the results are shown in Table 1.

[Comparative Example 6]
Preparation of Modified Zirconia Fine Particles (R6) Powder In Comparative Example 4, the organosilicon compound was hydrolyzed and then dried at 60 ° C. for 24 hours in a box dryer without solvent substitution. Fine particle (R6) powder was prepared.
The resulting modified zirconia fine particle (R4) powder was measured for water content, crystallinity, average particle diameter, angle of repose, and refractive index, and the results are shown in the table.

Preparation of Modified Zirconia Fine Particles (R6) Organic Solvent Dispersion In Example 1, modified zirconia fine particles (R6) organic solvent having a solid content concentration of 30% by weight was used except that modified zirconia fine particles (R6) powder was used. A dispersion was prepared.

The average particle diameter of the obtained modified zirconia fine particle (R6) methanol dispersion was measured, and the results are shown in the table.
Further, the dispersibility and stability of the modified zirconia fine particle (R6) methanol dispersion and the modified zirconia fine particle (R6) methyl isobutyl ketone dispersion having a solid content concentration of 30% by weight were evaluated, and the results are shown in the table.

Preparation of Modified Zirconia Fine Particle (R6) Organic Resin Dispersion In Example 1, modified zirconia fine particle (R6) organic resin having a solid content concentration of 30% by weight was used except that modified zirconia fine particle (R6) powder was used. A dispersion was prepared.
The resulting modified zirconia fine particle (R6) organic resin dispersion was evaluated for dispersibility, and the results are shown in the table.

Claims (10)

A modified zirconia fine particle powder surface-treated with an organosilicon compound represented by the following formula (1), having an average secondary particle diameter (D _M2 ) in the range of 5 to 500 nm, and an average primary particle diameter ( D _M1 ) is in the range of 5 to 500 nm, and the ratio (D _M2 ) / (D _M1 ) of the average secondary particle size (D _M2 ) to the average primary particle size (D _M1 ) is in the range of 1 to 10. ,
The content of the organosilicon compound in the modified zirconia fine particle powder is 1 to 50% by weight as R _n —SiO 2 _{(4-n) / 2} , and the half width of the main peak of the ²⁹ Si MAS NMR spectrum is 3 to 15 ppm. Modified zirconia fine particle powder characterized by that.
R _n -SiX _4-n (1)
(In the formula, R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms and may be the same or different. X is an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a halogen atom. Or hydrogen, n is an integer of 1 to 3.)   2. The modified zirconia fine particle powder according to claim 1, wherein an angle of repose is 45 ° or less. A method for producing modified zirconia fine particle powder in the order of the following steps (a) to (f), wherein the average secondary particle size (D _M2 ) is 5 to 500 nm, and the average primary particle size (D _M1 ) is 5 to 5. A method for producing modified zirconia fine particle powder having a ratio (D _M2 ) / (D _M1 ) of 1 to 10 of 500 nm and an average secondary particle size (D _M2 ) to an average primary particle size (D _M1 ).
(A) Peptization or dissolution of zirconium hydroxide gel in the presence of potassium hydroxide and hydrogen peroxide (b) Hydrothermal treatment step (c) Washing step (d) Zirconia fine particle water and / or organic Step (e) of preparing a dispersion of the solvent (f) Step of adding an organosilicon compound represented by the following formula (1) without adding a hydrolysis catalyst of the organosilicon compound to the dispersion (f) The organosilicon compound Step Rn-SiX _4-n (1) for drying at 200 ° C. or lower without substituting the dispersion with added solvent
(In the formula, R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms and may be the same or different. X is an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a halogen atom. Or hydrogen, n is an integer of 1 to 3.) The content of the organic silicon compound modified zirconia particles in the powder is _{R n -SiO (4-n)} / 2 (n is an integer of 1 to 3) is in the range of 1 to 50% by weight, ²⁹ Si MAS The method for producing a modified zirconia fine particle powder according to claim 3 , wherein the half width of the main peak of the NMR spectrum is in the range of 3 to 15 ppm. The average particle size (D _Z ) of the zirconia fine particles used in the step (d) is in the range of 5 to 400 nm, and the ratio (D _M2 ) / (D _Z ) with the average secondary particle size (D _M2 ) is 0. The method for producing the modified zirconia fine particle powder according to claim 3, wherein the method is 2 to 5.
(The average particle size (D _Z ) is measured by the dynamic light scattering method by ultrasonically dispersing a water content of 10% by weight using water as a dispersion medium.)   The method for producing modified zirconia fine particle powder according to claim 3, wherein in the step (b), hydrothermal treatment is performed in the presence of a particle growth regulator.   The method for producing modified zirconia fine particle powder according to claim 3 or 6, wherein the hydrothermal treatment temperature in the step (b) is in the range of 40 to 300 ° C. The drying in step (f)
The method for producing modified zirconia fine particle powder according to claim 3, wherein the method is carried out under flow or under reduced pressure at 200 ° C or lower.   A modified zirconia fine particle dispersion comprising the modified zirconia fine particle powder according to claim 1 or 2 dispersed in an organic solvent and / or an organic resin.   The modified zirconia fine particle dispersion according to claim 9, wherein the concentration of the modified zirconia fine particle powder is in the range of 1 to 70 wt% as a solid content.

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