JP2019172565A - Composite, manufacturing method of composite and manufacturing method of sintered body - Google Patents

Abstract

To enhance storage stability of a compound oxide particle having a perovskite type crystal phase in air.SOLUTION: A surface of a compound oxide particle is protected by coating the surface with a coating layer including carboxylic acid. Specifically, there is provided a composite having a compound oxide particle and the coating layer coating at least a part of a surface of the compound oxide particle, the compound oxide particle includes one or more element R selected from a group consisting of Ba, Sr, Ca, Mg, Al, Pb, Co and Zn, and one or more kind of element M selected from a group consisting of Ti, Zr, W, Nb, Hf and Sn, and has a perovskite type crystal phase constituted of the element R, the element M and oxygen, a molar ratio of the element R and the element M (R/M) in a composition of whole compound oxide particle is 0.85 to 1.15, and the coating layer includes carboxylic acid.SELECTED DRAWING: Figure 1

Description

  The present application discloses a composite of composite oxide particles having a perovskite crystal phase.

  Composite oxide particles having a perovskite crystal phase are widely used as dielectrics, optical materials and the like by taking advantage of their high dielectric constant and refractive index. In particular, in view of the dispersibility in a matrix resin and the development of ultra-high function due to the quantum size effect, a composite oxide having a small crystallite size or a composite oxide having a small particle size is required.

  A composite oxide having a perovskite crystal phase can be synthesized by, for example, a general solid phase method or a solvothermal method. However, in such a general method, the crystallite size and the particle size are sufficiently large. It is difficult to produce small particles. In this regard, various methods for producing composite oxide particles having a small crystallite size and particle size have been proposed.

  Patent Document 1 discloses a technique for synthesizing perovskite-type composite oxide particles while coexisting with a silane coupling agent in a solvothermal method using water and an organic solvent. As described above, it is considered that by allowing the silane coupling agent to coexist in the solvothermal method, the chemical stability of the composite oxide can be increased and composite oxide particles having a small particle diameter can be obtained.

  In Patent Document 2, in the solvothermal method using an oxygen-containing organic solvent such as alcohol, in the presence of an amine such as oleylamine, the element M (for example, Ti) constituting the B site of the perovskite type crystal phase is disclosed. A technique is disclosed in which particles containing an excessive amount of element R (for example, Ba) constituting the A site are obtained and the particles are washed with an acid. As described above, it is considered that the coexistence of amines in the solvothermal method can suppress the coarsening of the crystal of the composite oxide, and the composite oxide particles having a small crystallite diameter and a small particle diameter can be obtained. Further, it is considered that impurities derived from the element R can be removed by washing the particles containing the element R excessively with an acid.

JP 2013-177259 A JP 2017-186250 A

In the technique disclosed in Patent Document 1, an element M (for example, Ti or the like) constituting the B site is intentionally excessive with respect to an element R (for example, Ba or the like) constituting the A site of the perovskite crystal phase. There is a problem that impurities other than the perovskite type crystal phase (for example, TiO _{2 and the} like) are easily generated on the particle surface or inside the particle. In addition, in the technique disclosed in Patent Document 1, since a component derived from a silane coupling agent is included in the particles, there is a possibility that the dielectric constant and refractive index inherent to the perovskite complex oxide may be adversely affected.

On the other hand, as disclosed in Patent Document 2, when the element R constituting the A site of the perovskite-type crystal phase is made more excessive than the element M constituting the B site at the raw material charging stage, finally, In the obtained particles, there is a problem that impurities (BaCO ₃ or the like) derived from the element R are easily generated on the surface or inside thereof. In Patent Document 2, an attempt is made to remove impurities derived from the element R by washing the particles with an acid. However, the element R inside the particles is also removed at the same time, resulting in a shortage of the element R constituting the perovskite crystal phase. As in Patent Document 1, impurities other than the perovskite crystal phase (for example, TiO ₂ ) may be generated on the particle surface or inside the particle.

  Further, according to the new knowledge of the present inventors, in the perovskite type composite oxide particles, the element R constituting the A site of the perovskite type crystal phase reacts with carbon dioxide in the atmosphere, and the perovskite type crystal phase May not be maintained. That is, the perovskite complex oxide particles have a problem that storage stability in the atmosphere is poor.

  The present application is a composite comprising a composite oxide particle and a coating layer covering at least a part of the surface of the composite oxide particle as one of means for solving the above-described problem, wherein the composite oxide particle Is selected from the group consisting of one or more elements R selected from the group consisting of Ba, Sr, Ca, Mg, Al, Pb, Co and Zn and the group consisting of Ti, Zr, W, Nb, Hf and Sn. And a perovskite crystal phase composed of the element R, the element M, and oxygen, and the element R and the element M in the entire composition of the composite oxide particles. Disclosed is a composite having a molar ratio (R / M) of 0.85 or more and 1.15 or less, and the coating layer contains a carboxylic acid.

  In the composite of the present disclosure, it is preferable that an average crystallite diameter of the perovskite crystal phase in the composite oxide particle is 1 nm or more and 10 nm or less.

In the composite of the present disclosure, the BET specific surface area is preferably 50 m ² / g or more and 200 m ² / g or less.

  In the composite of the present disclosure, the element R is preferably one or more selected from the group consisting of Ba, Sr, Ca, and Mg.

  In the composite of the present disclosure, the element M is preferably one or more selected from the group consisting of Ti, Zr, and Hf.

  In the composite of the present disclosure, the carboxylic acid is preferably at least one of acrylic acid and acetic acid.

  In the present application, as one of means for solving the above problems, a precursor containing at least one element R selected from the group consisting of Ba, Sr, Ca, Mg, Al, Pb, Co, and Zn, and Ti A precursor containing at least one element M selected from the group consisting of Zr, W, Nb, Hf and Sn so that the element R is in an excess amount relative to the composition of the perovskite crystal phase. A first step of mixing to obtain a reaction solution, a second step of obtaining a solid content having a perovskite crystal phase by subjecting the reaction solution to a solvothermal method, and a solution containing the solid content and a carboxylic acid To remove impurities including the element R from the surface of the solid content, coat at least a part of the surface of the solid content with a coating layer containing carboxylic acid, and the element in the solid content R and before Molar ratio of the element M a (R / M) and 0.85 to 1.15, the third step comprises, discloses a method for manufacturing a composite body.

  In the method for producing a composite according to the present disclosure, it is preferable that an average crystallite diameter of the perovskite crystal phase in the solid content is 1 nm or more and 10 nm or less.

In the method for producing a composite according to the present disclosure, it is preferable to obtain a composite having a BET specific surface area of 50 m ² / g or more and 200 m ² / g or less.

  In the manufacturing method of the composite of this indication, it is preferable that the said element R is 1 or more types selected from the group which consists of Ba, Sr, Ca, and Mg.

  In the method for producing a composite according to the present disclosure, the element M is preferably at least one selected from the group consisting of Ti, Zr, and Hf.

  In the method for producing a composite according to the present disclosure, the carboxylic acid is preferably at least one of acrylic acid and acetic acid.

  In the method for producing a composite according to the present disclosure, the solution containing the carboxylic acid preferably contains the carboxylic acid, water, and an organic solvent, and the carboxylic acid is dissolved in both the water and the organic solvent. .

  In the method for producing a composite according to the present disclosure, the carboxylic acid, the water, and the organic solvent in the solution containing the carboxylic acid according to the amount of the element R contained in the solid content obtained in the second step. It is preferable to adjust the mixing ratio.

  In the method for producing a composite according to the present disclosure, in the third step, after the solid content and the solution containing the carboxylic acid are brought into contact with each other, the solid content is further washed with alcohol, and after washing with the alcohol It is preferable that the molar ratio (R / M) of the element R and the element M in the solid content is 0.85 or more and 1.15 or less.

  The composite of the present disclosure can be sintered and used for various applications. That is, this application discloses the manufacturing method of a sintered compact provided with the process of heating and sintering the composite_body | complex obtained by the manufacturing method of this indication as an example of the usage condition of the said composite_body | complex.

  As in the composite of the present disclosure, by covering at least a part of the surface of the composite oxide particle with carboxylic acid, the reaction between the element R in the particle and carbon dioxide in the atmosphere can be suppressed, and preservation in the air Stability can be improved. In addition, in the composite oxide particles finally obtained by obtaining a solid content by a solvothermal method and then treating the solid content with a predetermined carboxylic acid solution, as in the composite manufacturing method of the present disclosure The ratio of the element R to the element M (R / M) can be brought close to ideal 1 as a perovskite, and the surface of the composite oxide particle can be coated with carboxylic acid, so that the storage stability in the atmosphere It is possible to produce a composite excellent in the above.

1 is a schematic cross-sectional view for explaining a composite 10. It is a figure for demonstrating the flow of the manufacturing method (S10) of the composite_body | complex. FIG. 3 is a graph showing the result of powder X-ray diffraction measurement of Example 1. 6 is a graph showing the results of powder X-ray diffraction measurement of Example 2. FIG. It is a figure which shows the powder X-ray-diffraction measurement result of the comparative example 1. It is a figure which shows the powder X-ray-diffraction measurement result of the comparative example 2. It is a figure which shows the powder X-ray-diffraction measurement result of the comparative example 3.

  Embodiment described below is an example (representative example) of the embodiment of this invention, and this invention is not limited to these. That is, the present invention can be implemented with any changes without departing from the scope of the invention.

1. Complex Figure 1 schematically shows an example of an embodiment of a complex. The composite body 10 of the present embodiment is a composite body including the composite oxide particles 1 and a coating layer 2 that covers at least a part of the surface of the composite oxide particles 1. One or more elements R selected from the group consisting of Sr, Ca, Mg, Al, Pb, Co and Zn and one or more elements selected from the group consisting of Ti, Zr, W, Nb, Hf and Sn In addition to the element M, it has a perovskite crystal phase composed of the element R, the element M, and oxygen, and the molar ratio (R / M) of the element R to the element M in the composition of the composite oxide particle 1 as a whole Is 0.85 or more and 1.15 or less, and the coating layer 2 is characterized by containing a carboxylic acid.

1.1. Composite oxide particles 1
The element R constituting the composite oxide particle 1 is at least one selected from the group consisting of Ba, Sr, Ca, Mg, Al, Pb, Co, and Zn. From the viewpoint of obtaining composite oxide particles 1 in which the ratio of element R / element M is closer to 1, element R is preferably at least one selected from the group consisting of Ba, Sr, Ca, Mg and Pb, more preferably One or more selected from the group consisting of Ba, Sr, Ca and Mg, more preferably one or more selected from the group consisting of Ba, Sr and Ca, and particularly preferably Ba.

  The element M constituting the composite active material particle 1 is at least one selected from the group consisting of Ti, Zr, W, Nb, Hf, and Sn. From the viewpoint of obtaining composite oxide particles 1 in which the ratio of element R / element M is closer to 1, element M is preferably a tetravalent metal element, that is, one type selected from the group consisting of Ti, Zr, Sn, and Hf. More preferably, it is at least one selected from the group consisting of Ti, Zr and Hf, more preferably Ti and / or Zr, and particularly preferably Ti.

  The composite oxide particle 1 has one feature in that the molar ratio (R / M) between the element R and the element M is 0.85 or more and 1.15 or less in the entire composition. The lower limit of the molar ratio (R / M) is preferably 0.90 or more, and the upper limit is preferably 1.10 or less. In the composite oxide particle 1, the molar ratio (R / M) between the element R and the element M is not completely 1 in addition to the case where the perovskite crystal phase in the composite oxide particle 1 has a lattice defect. This is to allow a case where the oxide particles 1 include a different phase (including an amorphous phase) other than the perovskite crystal phase. That is, in the composite 10 of the present embodiment, the composite oxide particle 1 does not necessarily need to be composed only of the perovskite crystal phase. Needless to say, however, the larger the proportion of the perovskite crystal phase in the composite oxide particle 1, the better. The molar ratio (R / M) can be calculated by the method described in Examples described later.

When the composition of the perovskite crystal phase contained in the composite oxide particle 1 is expressed by the general formula R _x M _y O _{3 ± δ} , x and y are not particularly limited as long as the perovskite crystal phase can be maintained. . For example, it can be appropriately determined within a range satisfying 0 <x ≦ 1 and 0 <y ≦ 1. The composite oxide particle 1 has a feature that the composition of the whole particle is close to the composition of a perovskite crystal represented by RMO ₃ where x / y = 1. For example, in the case of a composite oxide particle containing Ba as the element R and Ti as the element M, it has a barium titanate (BaTiO ₃ ) phase as the perovskite type crystal phase, and the molar ratio of Ba and Ti as the composition of the entire particle 1 Ba / Ti is 0.85 or more and 1.15 or less.

In the present application, the general formula R _x M _y O _{3 ± δ} is a formula for representing a combination of the element R, the element M, and an oxygen atom in the perovskite crystal phase. Therefore, as long as it contains at least the element R, the element M, and the oxygen atom which are these essential constituent elements, the composite oxide particle 1 contains two or more elements M even if it contains two or more elements R. May contain other elements (hereinafter, also simply referred to as “element D”). The element D may be substituted with the A site element (element R) and / or the B site element (element M) of the perovskite crystal phase represented by the general formula R _x M _y O _{3 ± δ.} Good. A known element can be used as the element D depending on purposes such as stabilization of the crystal phase and suppression of charge transfer due to oxygen defects. For example, examples of the element D1 substituted at the A site include La, Bi, Y, Ce, Li, Na, Ag, K, and Fe. Examples of the element D2 substituted at the B site include Ta, Mn, Fe, and the like. Co, Ni, Cu etc. are mentioned. When the composite oxide particle 1 contains the element D, the content of the element D1 that substitutes for the A site is such that the total of the element R and the element D1 is 100 mol%, and the element D1 is 0.001 mol% or more and 1 mol%. The following is preferable, and 0.01 mol% or more and 0.1 mol% or less is more preferable. In addition, the content of the element D2 substituted for the B site is preferably 0.001 mol% or more and 1 mol% or less, and 0.01 mol% or more, with the total of the element M and the element D2 being 100 mol%. 0.1 mol% or less is more preferable.

Preferable examples (representative composition formulas) of the perovskite type crystal phase represented by the above-described general formula R _x M _y O _{3 ± δ} are shown below. In the following representative composition formula, 0 <x <1, 0 <y <1.
Barium titanate [BaTiO ₃ ],
Strontium titanate [SrTiO ₃ ],
Barium strontium titanate [(Ba _x Sr _1-x ) TiO ₃ ],
Calcium titanate [CaTiO ₃ ],
Barium zirconate titanate [Ba (Ti _y Zr _1-y ) O ₃ ],
Lead zirconate titanate [Pb (Ti _y Zr _1-y ) O ₃ ],
Zirconate titanate, barium strontium _{[(Ba x Sr 1-x} ) (Ti y Zr 1-y) O 3],
Barium calcium zirconate titanate [(Ba _x Ca _1-x ) (Ti _y Zr _1-y ) O ₃ ],
Barium zirconate [BaZrO ₃ ],
Strontium zirconate [SrZrO ₃ ],
Barium stannate [BaSnO ₃ ],
Strontium stannate [SrSnO ₃ ] and the like.

The perovskite crystal phase of the composite oxide particle 1 can be confirmed from an X-ray diffraction profile obtained by powder X-ray diffraction measurement. For example, in barium titanate (BaTiO ₃ ) having a perovskite crystal phase, in powder X-ray diffraction measurement, (100) plane, (110) plane, (111) plane, (200) plane, (210) plane, (211) ) Plane, (220) plane, (300) plane, (310) plane, etc., an X-ray diffraction pattern is obtained.

  The average crystallite size of the perovskite type crystal phase in the composite oxide particle 1 is not particularly limited, but is preferably 10 nm or less. The lower limit of the average crystallite diameter is not particularly limited, but is usually 1 nm or more. The average crystallite diameter is more preferably 2 nm or more, further preferably 3 nm or more, more preferably 8 nm or less, still more preferably 7 nm or less. If the average crystallite diameter is within the above preferred range, for example, the size effect is reduced, the refractive index difference from the organic component can be increased, and a high refractive index imparting effect tends to be obtained, and Rayleigh scattering is suppressed. Therefore, high transparency tends to be easily obtained. In addition, by setting the average crystallite diameter within the above range, when the dielectric layer is composed of the composite oxide particles 1, the dielectric layer can be thinned. Therefore, for example, even in a multilayer capacitor in which a plurality of dielectric layers are laminated, a reduction in size and an increase in capacity can be achieved. Furthermore, according to the knowledge of the present inventors, the composite oxide particles 1 having a small average crystallite size tend to have a small particle size as a whole, and are considered to be highly reactive with carbon dioxide in the atmosphere. However, by providing the coating layer 2 described later, the reaction with carbon dioxide can be more significantly suppressed. That is, in the composite oxide particle 1 having a small average crystallite diameter, the effect of the coating layer 2 becomes more remarkable.

The average crystallite diameter in the composite oxide particle 1 can be obtained from the following Scherrer equation from the half width of the crystallinity peak obtained by the powder X-ray diffraction method.
[Scherrer equation] Crystallite size (D) = K · λ / (β · cos θ)

Here, K is a Scherrer constant, K = 0.9, and X-ray (CuKα1) wavelength (λ) = 1.54056Å (1Å = 1 × 10 ⁻¹⁰ m). In order to further improve the accuracy, it is preferable to calculate the Bragg angle (θ) and the half-value width (βo) derived from the CuKα1 line using a profile fitting method (Peason-VII function). The half-value width β used for the calculation is preferably corrected from the half-value width βi derived from the apparatus obtained in advance by standard Si using the following formula.

  The composite oxide particle 1 preferably has photocatalytic activity. For example, titanium oxide (including complex oxides containing titanium as a constituent element) is known to have photocatalytic activity. Therefore, when titanium oxide is present on the surface of the composite oxide particle 1, the photocatalytic action can be confirmed.

1.2. Coating Layer The coating layer 2 is a layer that covers at least a part of the surface of the composite oxide particle 1 and is characterized by containing a carboxylic acid. The carboxylic acid only needs to be capable of adhering to the surface of the composite oxide particle 1 to form the coating layer 2, and may be a monocarboxylic acid or a polyvalent carboxylic acid, and its molecular weight is also particularly limited. Is not to be done. From the viewpoint of suppressing coloring, an aliphatic carboxylic acid is preferable. From the viewpoint that the surface of the composite oxide particle 1 can be more easily coated, the carboxylic acid is preferably at least one selected from acrylic acid and acetic acid, particularly preferably acrylic acid. By covering at least a part of the surface of the composite oxide particle 1 with the coating layer 2, the reaction between the composite oxide particle 1 and carbon dioxide in the air can be suppressed, and the storage stability in the air can be improved. it can. The coating layer 2 may contain components other than carboxylic acid as long as the above-described problems can be solved.

  The coating layer 2 only needs to cover at least a part of the surface of the composite oxide particle 1, but from the viewpoint of further improving the storage stability, as much of the surface of the particle 1 as possible is covered with the coating layer 2. It is preferable that For example, it is preferable that 1% or more of the surface of the composite oxide particle 1 is covered with the coating layer 2, more preferably 5% or more is covered with the coating layer 2, and 10% or more is the coating layer 2. It is particularly preferred that it is coated with.

  The thickness of the coating layer 2 is not particularly limited. It may be an extremely thin layer (thickness of about 1 molecule of carboxylic acid) for which it is difficult to measure the thickness. In other words, the composite 10 may be one in which carboxylic acid simply adheres to at least a part of the surface of the composite oxide particle 1. The presence / absence of the coating layer 2 on the surface of the composite oxide particle 1 can be determined by, for example, heating the composite 10 and analyzing components desorbed from the surface of the composite oxide particle 1 by gas chromatography or the like. is there.

  If the amount of the coating layer 2 is too large, not only the effect relating to storage stability is saturated, but also the characteristics such as the dielectric constant and refractive index, the handleability, etc. of the composite oxide particle 1 are impaired. From this viewpoint, the mass ratio of the coating layer 2 to the composite (coating layer / (composite oxide particle + coating layer)) is preferably 8% by mass or more and 50% by mass or less. The lower limit is more preferably 10% by mass or more, and the upper limit is more preferably 25% by mass or less.

1.3. Others The composite 10 only needs to include the composite oxide particles 1 and the coating layer 2, and the overall shape and physical properties are not particularly limited, but the following shapes and physical properties are particularly preferable.

  The complex oxide particles 1 having a small particle diameter have a large specific surface area and are highly reactive with carbon dioxide in the atmosphere, so the above-described problems are particularly likely to occur. That is, it can be said that the technology of the present disclosure exhibits a more remarkable effect when the particle diameter of the composite oxide particles 1 is small. Here, when the composite oxide particles 1 constituting the composite 10 have a small particle size, the composite 10 can have a small particle size. For example, the composite 10 preferably has an average dispersed particle size of 50 nm or less. Although a minimum is not specifically limited, Usually, it is 1 nm or more. Preferably it is 3 nm or more, More preferably, it is 5 nm or more, Preferably it is 45 nm or less, More preferably, it is 10 nm or less. The “average dispersed particle diameter” means the volume-based median diameter (D50) of dispersed particles measured using a dynamic light scattering particle size measuring device in a dispersion in which the composite 10 is dispersed in a solvent. To do. Note that a 2-methoxyethanol-containing solvent is used as the dispersion.

As described above, the complex oxide particles 1 having a large specific surface area are particularly susceptible to the above-described problems because of their high reactivity with carbon dioxide in the atmosphere. That is, it can be said that the technique of the present disclosure exhibits a more remarkable effect when the specific surface area of the composite oxide particle 1 is large. Here, when the specific surface area of the composite oxide particle 1 constituting the composite 10 is large, the composite 10 having a large specific surface area can be obtained. For example, the composite 10 preferably has a BET specific surface area of 50 m ² / g or more and 200 m ² / g or less. More preferably ^{80 m} 2 / g or more, still more preferably ^90m 2 / g or more, and more preferably 170m ² / g, more preferably not more than 140 m ² / g. Note that the BET specific surface area can be calculated by the method of Examples described later.

  As described above, according to the composite 10 according to the embodiment, by covering at least a part of the surface of the composite oxide particle 1 with the coating layer 2 containing carboxylic acid, the element R constituting the particle 1 and the atmosphere The reaction with carbon dioxide can be suppressed, and the storage stability in the air can be improved.

2. 2. Manufacturing method of composite_body | complex The example of the manufacturing method of the composite_body | complex 10 which concerns on embodiment is shown in FIG. The manufacturing method (S10) shown in FIG. 2 includes a precursor containing one or more elements R selected from the group consisting of Ba, Sr, Ca, Mg, Al, Pb, Co, and Zn, Ti, Zr, W And a precursor containing at least one element M selected from the group consisting of Nb, Hf, and Sn, and mixing them so that the element R is in an excessive amount with respect to the composition of the perovskite crystal phase. A first step (S1) for obtaining a liquid; a second step (S2) for obtaining a solid content having a perovskite crystal phase by subjecting the reaction solution to a solvothermal method; and the solid content and a carboxylic acid. By contacting with the solution, impurities containing the element R are removed from the surface of the solid content, and at least a part of the surface of the solid content is coated with a coating layer containing carboxylic acid, and the solid content is Before element R Molar ratio of the element M a (R / M) and 0.85 to 1.15, the third step (S3), and a.

2.1. First step (S1)
In the first step, a precursor containing element R and a precursor containing element M are mixed so that the amount of element R is excessive with respect to the composition of the perovskite crystal phase to obtain a reaction solution. In particular, it is preferable to mix an amine and an oxygen-containing organic solvent together with a precursor containing the element R and a precursor containing the element M. The reason why the element R is excessive is as follows. Usually, the element M such as Ti is more reactive than the element R such as Ba, so that the oxide derived from the element M (titanium oxide, etc.) other than the target perovskite type crystal phase in the composite oxide particles. Is produced in large quantities, and the element R is lost by a subsequent cleaning operation or the like, and as a result, the ratio of the element M is higher than that of the element R. Therefore, it is considered preferable to make the element R excessive in advance.
The reaction solution may contain other components as long as the above problems can be solved. For example, you may contain another additive as needed. In this case, a reaction solution in which the precursor, amines and additives are dissolved or dispersed in the oxygen-containing organic solvent is obtained.

2.1.1. As the precursor containing the element R and the precursor containing the element M, any substance can be used as long as desired composite oxide particles can be obtained. That is, it is possible to arbitrarily select and use an appropriate metal element or metal compound containing a metal element constituting the desired composite oxide particle. In addition, although the element mentioned above can be used for the element R and the element M, in order to obtain the metal oxide composite particle in which the ratio of element R / element M is close to 1 by the method described later, the element R is preferably One or more selected from the group consisting of Ba, Sr, Ca and Pb, more preferably one or more selected from alkaline earth metals, that is, Mg, Ca, Sr and Ba, and more preferably , Ca, Sr and Ba, and Ba is particularly preferable. On the other hand, for the same reason, the element M is preferably a tetravalent metal element, that is, one or more selected from the group consisting of Ti, Zr, Sn and Hf, more preferably from Ti, Zr and Hf. It is 1 or more types chosen from the group which consists of, More preferably, it is Ti and / or Zr, Most preferably, it is Ti.

  Examples of the precursor include metal chloride, metal acetate, metal alkoxide, metal hydroxide and the like. Among these, metal alkoxides, metal acetates, and metal hydroxides are preferable from the viewpoint of suppressing by-product impurities (for example, chlorides and the like). Among these, there is no particular limitation, but a combination of a metal hydroxide containing the element R and a metal alkoxide containing the element M is more preferable.

  Preferred examples of the precursor containing the element R include barium ethoxide, barium-2-ethylhexanoate, barium isopropoxide, barium methoxypropoxide, barium-2,4-pentanedionate hydrate, barium- 2,2,6,6-tetramethyl-3,5-heptanedionate, barium-2,2,6,6-tetramethyl-3,5-heptanedionate hydrate, barium titanium double alkoxide, barium zirconium Double alkoxide, barium hydroxide octahydrate,

  Bis (2,2,6,6-tetramethyl-3,5-heptanedionate) strontium hydrate, bis (2,2,6,6-tetramethyl-3,5-heptanedionate) strontium tetraglyme Adduct, bis (2,2,6,6-tetramethyl-3,5-heptanedionate) strontium triglyme adduct, strontium titanium double alkoxide, strontium zirconium double alkoxide, strontium hydroxide, strontium acetate, strontium-2 -Ethylhexanoate, strontium isopropoxide, strontium methoxypropoxide, strontium-2,4-pentandionate, strontium-2,2,6,6-tetramethyl-3,5-heptanedionate, etc. .

  Preferred examples of the elements other than barium and strontium mentioned above include alkoxides and hydroxides.

  Preferable examples of the precursor containing the element M include titanium methoxide, titanium ethoxide, titanium-di-n-butoxide (bis-2,4-pentandionate), titanium-diisopropoxide (bis-2, 4-pentandionate), titanium-diisopropoxide (bisethylacetoacetate), titanium-2-hexoxide, titanium-n-butoxide, titanium isopropoxide, titanium methoxypropoxide, titanium-n-nonyloxide, titanium oxide (Bistetramethylpentandionate), titanium-n-propoxide, titanium stearyl oxide, titanium triisostearyl isopropoxide, titanium trimethylsiloxide,

  Zirconium-n-butoxide, zirconium-t-butoxide, zirconium-di-n-butoxide (bis-2,4-pentandionate), zirconium-di-isopropoxide (bis-2,2,6,6,- Tetramethyl-3,5-heptanedionate), zirconium ethoxide, zirconium propoxide, zirconium-2-ethylhexanoate, zirconium-2-ethylhexoxide, zirconium isopropoxide, zirconium-2-methyl-2 -Butoxide, zirconium-2,4-pentanedionate, zirconium-n-propoxide, zirconium-2,2,6,6-tetramethyl-3,5-heptanedionate, zirconium trimethylsiloxide, zirconylpropionate ,

  Hafnium-n-butoxide, hafnium-t-butoxide, hafnium ethoxide, hafnium-2,4-pentanedionate, hafnium tetramethylheptanedionate and the like can be mentioned.

  As elements other than titanium, zirconium, and hafnium listed above, alkoxides are preferable examples.

  In addition, the precursor containing the element R and the precursor containing the element M may each be used individually by 1 type, and may use 2 or more types by arbitrary combinations and a ratio. Moreover, the precursor may exist in any state in the reaction solution. Usually, the precursor is often present in a dissolved state in an oxygen-containing organic solvent.

  In the first step, the precursor containing the element R, the precursor containing the element M, the amines, and the oxygen-containing organic solvent are added in an excessive amount with respect to the composition of the perovskite crystal phase. Thus, it is preferable to obtain a reaction solution by mixing. Note that “the amount of the element R is excessive with respect to the composition of the perovskite crystal phase” means that the molar ratio of the element R to the element M is larger than 1. The molar ratio (R / M) between the element R and the element M in the reaction solution depends on the composition ratio of the target perovskite crystal, but is preferably 1.05 or more and 10 or less, for example. The lower limit is more preferably 1.2 or more, particularly preferably 1.5 or more, and the upper limit is more preferably 8 or less, particularly preferably 4 or less.

2.1.2. Oxygen-containing organic solvent The oxygen-containing organic solvent functions as a reaction solvent when synthesizing the composite oxide particles from the precursor, and also functions as an oxygen supply source for supplying oxygen to the precursor. The oxygen-containing organic solvent is not particularly limited as long as it is an organic solvent containing an oxygen atom in the molecule, and an arbitrary one can be used.

  The number of carbon atoms in the oxygen-containing organic solvent is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1 or more, usually 30 or less, preferably 20 or less, more preferably 10 or less.

  The molecular weight of the oxygen-containing organic solvent is arbitrary, but is usually 32 or more, preferably 50 or more, more preferably 70 or more, and usually 500 or less, preferably 400 or less, more preferably 300 or less.

  The boiling point of the oxygen-containing organic solvent is arbitrary, but is usually 50 ° C. or higher, preferably 70 ° C. or higher, more preferably 100 ° C. or higher, more preferably 150 ° C. or higher, and usually 300 ° C. or lower, preferably 270 ° C. or lower. More preferably, it is 250 degrees C or less.

  The oxygen-containing organic solvent is roughly classified into alcohol solvents, glycol solvents, glycol ether solvents, glycol ester solvents, ketone solvents, aldehyde solvents, ether solvents, ester solvents, siloxane solvents, and the like. The type is not particularly limited. The number of oxygen atoms contained in one molecule of these oxygen-containing organic solvents is not particularly limited as long as it is 1 or more. Specific examples of the oxygen-containing organic solvent include ethanol, methanol, benzyl alcohol, 2-methoxyethanol, ethylene glycol, diethylene glycol, methylethanolamine, diethanolamine, acetone, benzaldehyde, cyclohexanone, acetophenone, diphenyl ether, hexamethyldisiloxane, and the like. However, it is not particularly limited to these. Among these, benzyl alcohol and 2-methoxyethanol are preferable. In addition, an oxygen-containing organic solvent can be used individually by 1 type, and can also use 2 or more types by arbitrary combinations and a ratio.

  The amount of the oxygen-containing organic solvent used is not particularly limited and can be set as appropriate. However, if the precursor concentration with respect to the solvent is too high, the average crystallite size of the resulting composite oxide particles may be too large. In this regard, it is preferable to use the oxygen-containing organic solvent so that the concentration of each complex oxide precursor in the oxygen-containing organic solvent is 0.1 mol / L or more and 1.0 mol / L or less. More preferably, it is 0.3 mol / L or more, More preferably, it is 0.5 mol / L or more, More preferably, it is 0.8 mol / L or less, More preferably, it is 0.6 mol / L or less. It is preferable to adjust the ratio of the precursor containing the element R and the precursor containing the element M to be in the above-described range.

2.1.3. Amines As amines, any of primary amines, secondary amines and tertiary amines can be used. However, primary amines and / or secondary amines are preferable, and primary amines are more preferable from the viewpoints of combined use effect of amines and oxidation degradation coloring.

  Of the amines, aliphatic amines are particularly preferable. This is because the action as a particle stabilizer at the time of synthesis is high. In particular, primary and / or secondary aliphatic amines are particularly preferable because they have the advantage of being highly effective as a particle growth promoter or inhibitor.

  The number of carbon atoms of the amines is arbitrary as long as the above-mentioned problems can be solved, but is usually 8 or more, preferably 14 from the viewpoint of the combined use effect as a particle stabilizer at the time of synthesis and the removability of amine modified at high temperature. Above, more preferably 16 or more, and usually 24 or less, preferably 20 or less, more preferably 18 or less.

  Specific examples of amines include, but are not limited to, oleylamine, octylamine, dioctylamine, aniline, methylethanolamine, diethanolamine and the like. In addition, amines can be used individually by 1 type, and can also use 2 or more types by arbitrary combinations and a ratio.

  In addition, the usage-amount of amines is not restrict | limited in particular, It can set suitably. In consideration of the average crystallite size and crystallinity of the resulting composite oxide particles, generation of impurities, etc., the molar ratio with respect to the precursor containing the element M is preferably 0.5 times or more, more preferably 1.5 times or more. More preferably, it is 2.0 times or more, and preferably 10 times or less, more preferably 6 times or less, and further preferably 4 times or less.

2.1.4. Other Additives In addition to the above-mentioned precursor, oxygen-containing organic solvent, and amines, additives may coexist in the reaction solution. Examples of the additive include carboxylic acids, solvents other than oxygen-containing organic solvents, phosphines, and the like, but are not particularly limited thereto.

  Carboxylic acids are for modifying the resulting composite oxide particles with carboxylic acids. By allowing carboxylic acids to coexist in the oxygen-containing organic solvent, composite oxide particles having carboxylic acids on the surface can be obtained. Therefore, the storage stability in the atmosphere can be improved as described above, and the solubility of the composite oxide particles in the organic solvent can be improved according to the application.

  The type of carboxylic acid is not particularly limited. Any carboxylic acid can be used as long as it can be bound to the composite oxide particles. From the viewpoint of suppression of coloring, aliphatic carboxylic acids are preferable.

  The number of carbon atoms of the carboxylic acids is arbitrary, but is preferably 8 or more, more preferably 14 or more, still more preferably 16 or more, from the viewpoint of the combined effect as a modifier and the removability of the carboxylic acid modified under high temperature. Moreover, 24 or less is preferable, More preferably, it is 20 or less, More preferably, it is 18 or less.

  Specific examples of the carboxylic acids include oleic acid, caprylic acid, behenic acid, stearic acid, myristic acid, and palmitic acid, but are not particularly limited thereto. In addition, carboxylic acids can be used individually by 1 type, and can also use 2 or more types by arbitrary combinations and a ratio.

  The amount of carboxylic acids used is not particularly limited and can be set as appropriate. In consideration of the combined effect as a modifier and the quality of the obtained composite oxide particles, the molar ratio with respect to the composite oxide precursor is preferably 0.1 times or more, more preferably 0.75 times or more, and further preferably Is preferably 1.0 times or more and 5 times or less, more preferably 3 times or less, and still more preferably 2 times or less.

  When amines and carboxylic acids are used in combination, the use ratio of the carboxylic acids is preferably 1/2 times or less, more preferably 1/4 times or less in terms of a molar ratio to the amines.

  The reaction solution may contain a solvent other than the oxygen-containing organic solvent. As long as the composite oxide particles described above can be obtained, there are no limitations on the type and amount of other solvents used. Examples of other solvents include water. Moreover, another solvent can be used individually by 1 type, and can also use 2 or more types by arbitrary combinations and a ratio.

2.1.5. Operation for preparing the reaction liquid The specific operation for preparing the reaction liquid is arbitrary. Moreover, the order which mixes the precursor mentioned above, an oxygen-containing organic solvent, amines, and the additive used as needed is also arbitrary. Generally, since many precursors react quickly with moisture in the air, it is preferable to mix them in an inert gas such as a nitrogen atmosphere. For example, after bubbling nitrogen-containing organic solvent for a predetermined time, a predetermined amount of the precursor is mixed and stirred, and then a predetermined amount of amines and additives are mixed.

2.2. Second step (S2)
In the second step, the reaction solution obtained in the first step is subjected to a solvothermal method, thereby obtaining a solid having a perovskite crystal phase (a synthetic solution containing the solid). The “solvothermal method” means a method for producing particles under a predetermined pressure at the synthesis temperature of the solvent.

  The reaction temperature in the solvothermal method is arbitrary as long as a solid content (composite oxide particles) having a perovskite crystal phase is obtained. One feature of this method is that composite oxide particles can be obtained at a relatively low temperature. From such a viewpoint, the reaction temperature is preferably 100 ° C. or higher, more preferably 150 ° C. or higher, and preferably 240 ° C. or lower, more preferably 200 ° C. or lower. If the reaction temperature is too low, the crystallinity tends to decrease, and if the reaction temperature is too high, the amount of by-products due to decomposition of organic substances tends to increase, and the quality of the composite oxide particles that can be obtained tends to decrease. The reaction temperature may be set in consideration of the balance.

  The reaction temperature may be constant or may vary. Further, the temperature of the reaction solution may be continuously within the range of the reaction temperature described above, or may be intermittently within the range. Furthermore, the temperature in the reaction solution may be uniform or non-uniform. Therefore, as long as the solid content (composite oxide particles) described above is obtained, for example, a part of the reaction solution may be outside the range of the reaction temperature.

  Moreover, the pressure conditions in the solvothermal method are also arbitrary. Usually, the pressure condition is below the self-pressure. Here, the self-pressure means the vapor pressure of the oxygen-containing organic solvent at the temperature.

  Furthermore, the reaction time in the solvothermal method is also arbitrary. One of the advantages of this method is that, in particular, composite oxide particles can be obtained in a shorter time than before by allowing a precursor, an oxygen-containing organic solvent, and amines to coexist in the reaction system. Although there is no particular limitation on the reaction time, when the average crystallite size is reduced (preferably 1 nm or more and 10 nm or less), it is preferably 1 minute or more, more preferably 5 minutes or more, It is particularly preferable that it is 30 minutes or longer. On the other hand, if the reaction time is too long, the average crystallite size contained in the solid content may become too large. Therefore, when reducing the average crystallite size (preferably 1 nm or more and 10 nm or less), The reaction time is preferably 48 hours or less, more preferably 24 hours or less.

  Moreover, the atmosphere at the time of reaction in the solvothermal method is also arbitrary. In general, the reaction is preferably performed in an inert atmosphere. This is because many of the precursors react quickly with moisture in the air. Here, the inert atmosphere means an atmosphere that is inert to any of the precursor, the oxygen-containing organic solvent, and the amines. Examples of the atmospheric gas constituting the inert atmosphere include nitrogen, argon, helium, and the like. In addition, a single inert gas can be used for the inert atmosphere, and two or more inert gases can be used in any combination and ratio.

  In the solvothermal method, in order to satisfy the above reaction conditions, for example, the reaction solution may be held at the predetermined reaction temperature in a sealed container. For example, the reaction solution may be sealed in an airtight container (such as an autoclave container) under an inert atmosphere and heated in the airtight container to maintain the predetermined reaction temperature.

  The preparation of the reaction solution and the progress of the reaction can be performed as a series of steps. For example, if the precursor, oxygen-containing organic solvent, amines, and additives as necessary are mixed in an environment in which predetermined reaction conditions are prepared in advance, the preparation of the reaction solution and the progress of the reaction can be distinguished from each other. It is possible to carry out as a series of steps that are not performed.

2.3. Third step (S3)
In the third step, the solid content obtained in the second step is brought into contact with the solution containing the carboxylic acid to remove impurities including the element R from the surface of the solid content and at least one of the surface of the solid content. The part is covered with a coating layer containing carboxylic acid, and the molar ratio (R / M) of element R to element M in the solid content is set to 0.85 or more and 1.15 or less.

  The “solution containing a carboxylic acid” used in the third step may be a solution in which at least a part of the carboxylic acid is dissolved in a solvent. As the carboxylic acid, the above-mentioned ones are preferably used. That is, an aliphatic carboxylic acid is preferable, at least one of acrylic acid and acetic acid is more preferable, and acrylic acid is particularly preferable. As the solvent, water or an organic solvent can be used. The organic solvent is preferably a water-soluble organic solvent, although it depends on the type of carboxylic acid to be dissolved. Among these, water-soluble alcohols are preferable, and specific examples include methanol, ethanol, isopropanol, benzyl alcohol, and methoxyethanol.

  The concentration of the carboxylic acid in the solution containing the carboxylic acid is not particularly limited as long as the molar ratio (R / M) can be 0.85 or more and 1.15 or less. For example, a carboxylic acid solution of less than 5% by mass is preferable. The “carboxylic acid solution of less than 5% by mass” means a solution containing a carboxylic acid component and having a carboxylic acid component concentration of less than 5% by mass. By performing the third step using such a solution, it is possible to remove only the element R component in the amorphous component on the solid content surface. Therefore, in the composition of the entire composite oxide particle finally obtained, the molar ratio (R / M) between the element R and the element M can be 0.85 or more and 1.15 or less. If the carboxylic acid concentration in the solution is too high, not only the excess element R in the solid content is removed, but also the element R constituting the perovskite crystal phase is ionized and removed, resulting in the above-described moles. A perovskite crystal phase having a ratio (R / M) may not be obtained. The lower limit of the concentration of the carboxylic acid solution in the third step is more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, particularly preferably 0.3% by mass or more, and the upper limit is more preferably. It is 2.5 mass% or less, More preferably, it is 1 mass% or less.

  When the solid content is brought into contact with the carboxylic acid solution, if the amount of the carboxylic acid relative to the solid content is too small, it is insufficient to remove the excess element R, and if it is too large, the excess of the element R may be removed. There is. From this viewpoint, the amount of the carboxylic acid relative to the solid content is preferably 0.05 times or more, more preferably 0.1 times or more, and particularly preferably 0.15 times or more in terms of mass ratio. On the other hand, it is more preferably 1.25 times or less, and particularly preferably 0.5 times or less.

  The solution containing carboxylic acid used in the third step contains carboxylic acid, water, and an organic solvent, and the carboxylic acid is preferably dissolved in both water and the organic solvent. Carboxylic acid dissolved in water and ionized is highly reactive with impurities derived from element R. On the other hand, the carboxylic acid dissolved in the organic solvent can be adsorbed on the surface of the solid content and remain as a coating layer. That is, by contacting carboxylic acid dissolved in water and an organic solvent with the solid content, the surface of the solid content is easily covered with the coating layer 2 while efficiently removing impurities derived from the element R from the solid content. be able to.

  In this case, it is preferable to adjust the mixing ratio of the carboxylic acid, water, and organic solvent in the solution containing the carboxylic acid according to the amount of the element R contained in the solid content obtained in the second step. That is, in an amount sufficient to remove impurities on the surface of the solid content, and in an amount that does not cause a reaction as much as possible with the element R constituting the perovskite crystal phase present in the solid content (inside the particle), Carboxylic acid may be dissolved in water.

  A specific method of bringing the solid content into contact with the solution containing the carboxylic acid is not particularly limited, but the carboxylic acid solution may be added to the solid content to disperse the solid content, and then centrifuged. . In this case, the composite 10 is obtained by recovering the sediment from centrifugation.

  The number of times that the solid content is brought into contact with the carboxylic acid solution is not particularly limited, and the amount of the solid content obtained in the second step or the element R and the element M contained in the reaction solution in the first step. In consideration of the molar ratio (R / M) and the like, each may be performed an appropriate number of times.

  In the third step, in order to remove a trace amount of impurities (impurities including an element R such as a carbonic acid compound or an agglomerated complex oxide) remaining after the treatment with the carboxylic acid solution, the solid content and the carboxylic acid are used. After contacting the solution containing the solid, the solid content is further washed with alcohol, and the molar ratio (R / M) of element R to element M in the solid content after washing with alcohol is 0.85 or more and 1.15 or less. It is preferable that The alcohol is preferably a hydrophilic alcohol. For example, alcohol having 2 or more carbon atoms is preferable, and ethanol is more preferable. Moreover, in order to increase the dispersibility of the composite oxide particles at the time of cleaning and enhance the cleaning effect, two or more kinds of alcohols or solvents other than alcohols may be contained. An oxygen-containing organic solvent used as a reaction solvent at the time of synthesizing the composite oxide particles is preferable, and 2-methoxyethanol is particularly preferable. Although the method of washing with alcohol is not particularly limited, for example, it is preferable to add the solid content after the treatment with the carboxylic acid solution to the alcohol and mix and stir. Thereafter, the supernatant liquid obtained by centrifugation or the like is concentrated and dried to recover the composite 10 again as a solid content. The amount of alcohol added to the solid content is not particularly limited, but is preferably 5 times or more, more preferably 10 times or more, and 50 times or less in terms of mass ratio. Is preferable, and it is more preferable that it is 20 times or less. By performing such an operation, the molar ratio (R / M) between the element R and the element M can be made closer to 1 which is ideal as a perovskite crystal. In the solid content (composite 10) obtained after the treatment with the carboxylic acid solution, since the carboxylic acid is relatively firmly bonded to the surface of the composite oxide particle 1, it may be washed with alcohol. The carboxylic acid is not easily detached from the surface of the composite oxide particle 1.

  In the third step, after contacting the solid content with the carboxylic acid solution (or after contacting with the carboxylic acid solution and further washing with alcohol), the solvent (for example, alcohol) is removed as necessary. To do. The removal of the solvent can be performed, for example, under reduced pressure and / or heating. Or you may use as a below-mentioned dispersion liquid as it is, without removing a solvent. For example, the above supernatant can be used as a dispersion as it is.

  In order to remove impurities in the synthesis solution in the second step, the solid content in the synthesis solution obtained in the second step is treated with a hydrophilic organic solvent before treatment with the carboxylic acid solution. It is preferable. Specifically, a hydrophilic organic solvent is added to the synthesis solution containing the solid content obtained in the second step, mixed and stirred, and then subjected to centrifugal separation. What is necessary is just to perform a process. In addition, methanol, ethanol, n-propanol, and isopropanol are mentioned as a hydrophilic organic solvent in this case. In particular, in the third step, it is preferable to recover the solid content after mixing methanol with the synthesis solution containing the solid content obtained in the second step, and to contact the recovered solid content with the carboxylic acid solution. . The amount of the hydrophilic organic solvent added to the synthetic solution obtained in the second step is not particularly limited, but is preferably 1 or more and more preferably 2 or more as a mass ratio. On the other hand, it is preferably 100 times or less, particularly preferably 10 times or less.

  The number of operations described above in the third step is not particularly limited. Considering the amount of solid content obtained in the second step, the molar ratio (R / M) between the element R and the element M contained in the reaction solution in the first step, etc. Good.

  As described above, according to the production method S10, the solid content obtained by the predetermined solvothermal method (S1, S2) is brought into contact with the solution containing the carboxylic acid, so that the impurity containing the element R is removed from the surface of the solid content. At the same time, at least a part of the surface of the solid content is covered with a coating layer containing carboxylic acid, and the molar ratio (R / M) of the element R to the element M in the solid content is 0.85 or more and 1.15 or less. It can be. That is, the ratio (R / M) of the element R to the element M in the composite oxide particle 1 can be brought close to ideal 1 as a perovskite crystal, and at least a part of the surface of the composite oxide particle 1 can be obtained. The composite 10 can be coated with the coating layer 2 containing carboxylic acid, and the storage stability in the air can be improved.

3. Dispersion The composite 10 of the present embodiment can also be used as a dispersion depending on the application. The dispersion liquid of this embodiment contains the composite 10 and the solvent described above. The complex 10 is as described above, and a description thereof is omitted here.

3.1. Solvent The solvent of the dispersion liquid is not particularly limited as long as the composite 10 can be dispersed. From the viewpoint of the dispersibility of the composite 10, an organic solvent is preferably used. Suitable organic solvents include aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, alcohol solvents, ester solvents, ether solvents, ketone solvents, glycol solvents, glycol ether solvents, glycol ester solvents. Etc.

  Aromatic hydrocarbon solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as normal hexane, isohexane, cyclohexane, normal heptane, isooctane, normal decane, etc., alcohol solvents such as methanol, ethanol, and normal propanol , Isopropanol, normal butanol, isobutanol, tertiary butanol, secondary butanol, 1,3-butanediol, 1,4-butanediol, 2-ethyl-1-hexanol, benzyl alcohol, tetrahydrobenzyl alcohol, 3-methoxybutanol, 1,3-butylene glycol, terpineol, dihydroterpineol, dihydroterpinyloxyethanol, 2- (1-methyl-1- (4-methyl-3-cyclohexenyl) Ethoxy) ethanol (trade name: Tersolve TOE-100 (produced by Nippon Terpene Chemical Co., Ltd.)), isobornylcyclohexanol (trade name: Tersolve MTPH (produced by Nippon Terpene Chemical Co., Ltd.)), etc. Methyl acetate, butyl acetate, sec-butyl acetate, methoxybutyl acetate, amyl acetate, normal propyl acetate, isopropyl acetate, methyl lactate, ethyl lactate, butyl lactate, cyclohexanol acetate, propylene glycol diacetate, dipropylene glycol methyl ether acetate, 1,4-butanediol diacetate, 1,3-butylene glycol diacetate, 1,6-hexanediol diacetate, 3-methoxybutyl acetate, ethylene glycol monobutyl ether acetate, triacetin, dihydro Droterpinyl acetate, isobornyl acetate, 4- (1′-acetoxy-1′-methylethyl) -cyclohexanol acetate (trade names: Tersolve THA-90, Tersolve THA-70 (manufactured by Nippon Terpene Chemical Co., Ltd.)) Examples of ether solvents include 1,4-dioxane, isopropyl ether, dipropylene glycol dimethyl ether, dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl-n-butyl ether, terpinyl methyl ether, dihydroterpi Nylmethyl ether, etc., ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol, etc., glycol solvents such as ethylene glycol, diethylene glycol, triethylene glycol Examples of glycol ether solvents such as alcohol and 1,2-dihydroxypropane include 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-isopropoxyethanol, 2-butoxyethanol, 2-tert-butoxyethanol. 2-isobutoxyethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether, 3-methoxy-3-methyl-1-butanol, diethylene glycol mono Hexyl ether, propylene glycol monomethyl ether propionate, dipropylene glycol Examples of the glycol ester solvent such as tilether include propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, and other special solvents such as tetrahydrofuran, 2-methyltetrahydrofuran, and cyclopentylmethyl. Examples include ether, N-methylpyrrolidone, dimethyl sulfoxide, dimethylformamide and the like. Among these, oxygen-containing organic solvents that can be used in the solvothermal method are good, and alcohol solvents and glycol ether solvents are particularly preferable. In addition, these can be used individually by 1 type and can also use 2 or more types by arbitrary combinations and a ratio.

  The composition of the dispersion is not particularly limited as long as it contains at least the composite 10 and the solvent. For example, in an optical application, the dispersion contains a precursor (for example, a matrix resin or monomers) for forming an optical material (molded body), a polymerization initiator, a polymerization accelerator, a polymerization inhibitor, a curing agent, and the like. May be. The dispersion may contain various additives known in the art, such as a dispersant, an antioxidant and the like. Hereinafter, these optional components will be described in detail.

3.2. Resin / Monomer Various known resins / monomers can be used, and the type is not particularly limited. When used as an optical material, a resin having transparency in the ultraviolet region to the near infrared region is preferable. For example, a resin obtained by polymerizing or copolymerizing a monomer having a functional group capable of radical polymerization with radiation or heat (hereinafter also referred to as “polymerizable functional group”) using a polymerization initiator as necessary. Can be preferably used. Further, from the viewpoint of productivity and the like, a curable monomer polymerizable by radiation (hereinafter also referred to as “radiation curable monomer”) was polymerized or copolymerized using a polymerization initiator as necessary. Resins are preferred. The type of radiation curable monomer is not particularly limited, but an ultraviolet curable monomer is preferable from the viewpoint of productivity and the like.

  The resin used here may be a resin obtained by polymerizing a monomer having a polymerizable functional group (hereinafter also referred to as “monofunctional monomer”), and a monomer having two or more polymerizable functional groups ( Hereinafter, it may be any of the resins obtained by polymerizing the “polyfunctional monomer”, but from the viewpoint of easy control of flexibility, two or more types of polymerizable functional groups are different. A resin obtained by copolymerizing monomers is preferred. Preferred resins include at least one selected from acrylic resins, methacrylic resins, epoxy resins, and silicone resins from the viewpoints of transparency, refractive index, and productivity.

  These resin can be used individually by 1 type, and can also use 2 or more types by arbitrary combinations and a ratio. When two or more types of resins are used, the types and ratios of the resins to be combined are arbitrary. From the viewpoint of easy control of flexibility, it is preferable that at least one of an acrylic resin and a methacrylic resin is a main component. In addition, a main component means the component which occupies 50 mass% or more. Specific examples of the combination of resins include a combination of an acrylic resin and a methacrylic resin, at least one of an acrylic resin and a methacrylic resin as a main component, and an epoxy resin, a silicone resin, or an epoxy resin and a silicone resin as a subcomponent. Combination, etc. are mentioned.

  Among these, it is preferable to include at least one of an acrylic resin and a methacrylic resin, and a resin obtained by copolymerizing at least one of an acrylic resin and a methacrylic resin is most preferable.

  As the monomer constituting the resin component, a monomer having an acryloyl group, a methacryloyl group, and / or an epoxy group as a functional group capable of radical polymerization by radiation is preferably used.

  Hereinafter, monomers suitably used as monomers constituting an acrylic resin, a methacrylic resin, an epoxy resin, and a silicone resin, and a polymerization initiator and a curing agent that are used as necessary are exemplified.

(I) A monomer constituting the acrylic resin and / or methacrylic resin and a polymerization initiator [monomer]
As the monomer constituting the acrylic resin and methacrylic resin, a monomer having an acryloyl group and / or a methacryloyl group is preferably used. The monomer having an acryloyl group and / or a methacryloyl group may be monofunctional or polyfunctional, and may be aliphatic (including alicyclic) or aromatic. “(Meth) acrylate” means one or both of “acrylate” and “methacrylate”. The same applies to “(meth) acryl”. Examples of the monofunctional (meth) acrylate monomer include monofunctional aliphatic (including alicyclic) (meth) acrylate monomers and monofunctional aromatic (meth) acrylate monomers. Examples of the polyfunctional (meth) acrylate monomer include a bifunctional (meth) acrylate monomer and a tri- or higher functional (meth) acrylate monomer. Examples of the bifunctional (meth) acrylate monomer include a bifunctional aliphatic (including alicyclic) (meth) acrylate monomer and a bifunctional aromatic (meth) acrylate monomer. Examples of the tri- or more functional (meth) acrylate monomers include polyfunctional aliphatic (including alicyclic) (meth) acrylate monomers and polyfunctional aromatic (meth) acrylate monomers. These monomers can be used alone or in combination of two or more. Specific examples of these monomers include the following.

<Monofunctional aliphatic (including alicyclic) (meth) acrylate monomers>
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl ( (Meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, allyl (meth) acrylate, methallyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, polyethylene glycol monoalkyl ether (meth) acrylate Polypropylene glycol monoalkyl ether (meth) acrylate, nonyl (meth) acrylate, norbornyl (meth) acrylate, decyl (meth) acrylate, 2-bromophenoxyethyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, Lauryl (meth) acrylate, n-stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, adamantyl (meth) acrylate, acrylonitrile 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2 Hydroxybutyl (meth) acrylate, polytetramethylene glycol mono (meth) acrylate, 2- (meth) acryloyloxyethyl-2-hydroxyethylphthalic acid, glycerin mono (meth) acrylate, 2- (meth) acryloyloxyethyl 2-hydroxypropyl phthalate, terminal hydroxyl group polyester mono (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, polypropylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate , Polyethylene glycol-polypropylene glycol mono (meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate, octoxypolyethylene glycol-poly Propylene glycol mono (meth) acrylate, 2- (meth) acryloyloxyethyl acid phosphate, mono (2-methacryloyloxyethyl) acid phosphate, mono (2-acryloyloxyethyl) acid phosphate, allyl (meth) acrylate, 2- ( (Meth) acryloyloxyethyl acid phosphate monoester, (meth) acrylic acid, carbitol (meth) acrylate, butoxyethyl (meth) acrylate, monofunctional urethane (meth) acrylate, monofunctional epoxy (meth) acrylate, monofunctional polyester ( (Meth) acrylate, (meth) acryloylmorpholine and the like.

  Among these, linear aliphatic (meth) acrylates, (meth) acrylates having an ethylene glycol chain or a propylene glycol chain, hydroxy acrylates, and phosphate group-containing acrylates are preferably used.

<Monofunctional aromatic (meth) acrylate monomer>
Phenyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, phenoxy-2-methylethyl (meth) acrylate, phenoxyethoxyethyl (meth) acrylate, 3-phenoxy-2-hydroxypropyl (meth) acrylate, 2-phenylphenoxy Ethyl (meth) acrylate, 4-phenylphenoxyethyl (meth) acrylate, 3- (2-phenylphenyl) -2-hydroxypropyl (meth) acrylate, (meth) acrylate of ethylene oxide modified p-cumylphenol, 2-bromo Phenoxyethyl (meth) acrylate, 2,4-dibromophenoxyethyl (meth) acrylate, 2,4,6-tribromophenoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate 2-phenoxy-2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, benzyl (meth) acrylate, phenol ethylene oxide modified (n = 2) (meth) acrylate, nonylphenol propylene oxide modified (N = 2.5) (meth) acrylate, diphenyl-2- (meth) acryloyloxyethyl phosphate, o-phenylphenol glycidyl ether (meth) acrylate, 2- (meth) acryloyloxy-2-hydroxypropyl phthalate, etc. Half (meth) acrylate of phthalic acid derivative, monofunctional (meth) acrylate containing fluorene skeleton, hydroxyethylated o-phenylphenol (meth) acrylate, furfuryl (meth) acrylate Etc..

  Among these, phenyl (meth) acrylates, phenoxy acrylates, and fluorene skeleton-containing monofunctional (meth) acrylates are preferably used.

<Bifunctional aliphatic (including alicyclic) (meth) acrylate monomers>
Neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, 1, 3-adamantanediol di (meth) acrylate, glycerin di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, 2-butyl-2-ethyl-1,3-propanediol di (meth) acrylate, 2 Functional urethane (meth) acrylate, bifunctional epoxy (meth) acrylate, bifunctional polyester (meth) acrylate, polyethylene glycol diacrylate, polypropylene glycol di (meth) acrylate, neope Tyrglycol hydroxypivalic acid ester di (meth) acrylate, neopentyl glycol modified trimethylolpropane di (meth) acrylate, caprolactone modified di (meth) acrylate of hydroxypivalic acid neopentyl glycol ester, tris (2-hydroxyethyl) isocyanurate di (Meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolmethane di (meth) acrylate, 2- (meth) acryloyloxyethyl-2-hydroxyethylphthalic acid glycerol mono (meth) acrylate, 3- (meta ) Acryloyloxyglycerin mono (meth) acrylate and the like.

<Bifunctional aromatic (meth) acrylate monomer>
EO (epoxy) adduct of bisphenol A di (meth) acrylate, trimethylolpropane (meth) acrylic acid benzoate, 9,9-bis [4- (2- (meth) acryloyloxyethoxy) phenyl] fluorene, fluorene Skeletal-containing bifunctional (meth) acrylate, bisphenol A di (meth) acrylate, ethylene oxide modified bisphenol A (meth) acrylate, propylene oxide modified bisphenol A (meth) acrylate, reaction of bisphenol A with glycidyl (meth) acrylate Epoxy (meth) acrylate obtained by reaction with ethylene oxide-modified bisphenol A and glycidyl (meth) acrylate and propylene oxide-modified bisphenol A Epoxy (meth) acrylate obtained by reaction of a Rishijiru (meth) acrylate.

<Trifunctional or higher aliphatic (meth) acrylate monomers>
Dipentaerythritol monohydroxypenta (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, trimethylolpropane tri ( (Meth) acrylate, polyfunctional urethane (meth) acrylate, polyfunctional epoxy (meth) acrylate, polyfunctional polyester (meth) acrylate, tris [2-((meth) acryloyloxy) ethyl] isocyanurate, tris [2-(( (Meth) acryloyloxy) propyl] isocyanurate, 2,4,6-tris ((meth) acryloyloxyethoxy) -1,3,5-triazine and the like.

<Trifunctional or higher aromatic (meth) acrylate monomer>
Fluorene skeleton-containing polyfunctional (meth) acrylate, 2,4,6-tris ((meth) acryloyloxypropoxy) -1,3,5-triazine and the like.

  Among these (meth) acrylate monomers, monofunctional aromatic (meth) acrylate monomers are preferable from the viewpoint of improving heat resistance. That is, introducing an aromatic ring into the molecular structure of the resin is effective for improving heat resistance. Among the acrylate monomers introduced with an aromatic ring, those having high heat resistance include those having a naphthalene structure, a fluorene structure, a bisphenol A structure, and the like.

  Among (meth) acrylate monomers, urethane (meth) acrylates such as urethane (meth) acrylate and urethane (meth) acrylate oligomer are effective as components for imparting flexibility to the obtained inorganic-organic hybrid material. It is. In addition, the monomer which has a polar functional group in a (meth) acrylate type monomer can be used as a surface treating agent for composite oxide particles. Examples of such monomers include 2- (meth) acryloyloxyethyl-2-hydroxyethylphthalic acid, 2- (meth) acryloyloxyethyl acid phosphate, mono (2-methacryloyloxyethyl) acid phosphate, mono (2- Examples include half (meth) acrylates of phthalic acid derivatives such as (acryloyloxyethyl) acid phosphate, (meth) acrylic acid, 2- (meth) acryloyloxy-2-hydroxypropyl phthalate, and the like.

[Polymerization initiator]
The type of polymerization initiator for polymerizing these monomers is not particularly limited as long as it can perform various polymerization reactions, but a radical polymerization initiator capable of performing a radical polymerization reaction is preferable. For example, polymerization initiators such as acetophenones, benzophenones, benzoin ethers, hydroxyketones, acylphosphine oxides, diazonium cation onium salts, iodonium cation onium salts, sulfonium cation onium salts, depending on the type of curable monomer Can be used as appropriate.

  Specifically, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 1-hydroxy-cyclohexyl phenyl ketone, 2,2-dimethoxy-1 , 2-diphenylethane-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, 2-benzyl-2-dimethylamino-1- (4-morpho Linophenyl) butanone-1,2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-methyl-1- [4-methylthio] phenyl] -2-morpholinopropan-1-one, benzoin methyl Ether, benzoin ethyl ether, benzoin isobutyl ether, benzoin iso Propyl ether, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, 2-hydroxy-2-methyl- [4- (1-methylvinyl) phenyl] propanol oligomer, isopropylthioxanthone, methyl o-benzoylbenzoate, [4- (Methylphenylthio) phenyl] phenylmethane, 2,4-diethylthioxanthone, 2-chlorothioxanthone, benzophenone, ethyl anthraquinone, benzophenone ammonium salt, thioxanthone ammonium salt, bis (2,6-dimethoxybenzoyl) -2, 4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, 4,4'-bisdiethylaminobenzophenone, 1,4-dibenzoy Benzene, 10-butyl-2-chloroacridone, 2,2′-bis (o-chlorophenyl) -4,5,4 ′, 5′-tetrakis (3,4,5-trimethoxyphenyl) -1,2 '-Biimidazole, 2,2'-bis (o-chlorophenyl) -4,5,4', 5'-tetraphenyl-1,2'-biimidazole, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4- Benzoyldiphenyl ether, acrylated benzophenone, dibenzoyl, bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium, o -Methylbenzoylbenzoate, p-dimethylaminobenzoic acid ethyl ester, p-dimethylaminobenzoic acid isoamyl ethyl ester, Tertiary amine, carbazole / phenone photopolymerization initiator, acridine photopolymerization initiator, triazine photopolymerization initiator, benzoyl, triallylsulfonium, hexafluorophosphate salt, phosphorus hexafluoride aromatic sulfonium Salt, antimony hexafluoride aromatic sulfonium salt, antimony hexafluoride aromatic sulfonium salt, antimony hexafluoride aromatic sulfonium salt, triallylsulfonium, hexafluoroantimony, 4-methylphenyl- [4- (2-Methylpropyl) phenyl] -hexafluorophosphate (1-), 1,2-octanedione, 1- [4- (phenylthio) -2- (o-benzoyloxime)], 1- [9-ethyl -6- (2-methylbenzoyl) -9H-carbazol-3-yl] -1- ( -Acetyloxime), ethyl-4-dimethylaminobenzoate, ethyl-4-dimethylaminobenzoate, 2-ethylhexyl-4-dimethylaminobenzoate, (9-oxo-9H-xanthen-2-yl) phenyliodonium hexafluorophosphate, bis [4-n-alkyl (C10-13) phenyl] iodonium hexafluorophosphate, bis [4-n-alkyl (C10-13) phenyl] iodonium hexafluoroantimony, triphenylsulfonium trifluorosulfonate, triphenylsulfonium bicyclo [ 2,2,1] heptane-1-methanesulfonate, (9-oxo-9H-xanthen-2-yl) phenylsulfonium hexafluorophosphate, p-azidobenzaldehyde, p- Azidoacetophenone, p-azidobenzoic acid, p-azidobenzaldehyde-2-sulfonic acid Na salt, p-azidobenzalacetophenone, 4,4′-diazidochalcone, 4,4′-diazidodiphenyl sulfide, 3,3 '-Diazidodiphenyl sulfide, 2,6-bis- (4'-azidobenzal) -4-methylcyclohexane, 1,3-bis- (4'-azidobenzal) -propanone, 4,4'-diazidochalcone-2 -Sodium sulfonate, 4,4'-diazidostilbene-2,2'-disulfonic acid Na salt, 1,3'-bis- (4'-azidobenzal) -2'-disulfonic acid Na salt-2-propanone 2,6-bis- (4′-azidobenzal) -2′-sulfonic acid (Na salt) cyclohexanone, 2,6-bis- (4′-azidobenzal) -2'-sulfonic acid (Na salt) 4-methyl-cyclohexanone, α-cyano-4,4'-dibenzostilbene, 2,5-bis- (4'-azidobenzalsulfonic acid Na salt) cyclopentanone, 3-sulfonyl azidobenzoic acid, 4-sulfonyl azidobenzoic acid, cinnamic acid, α-cyanocinnamylideneacetic acid, p-azido-α-cyanocinnamic acid, p-phenylene diacrylic acid, p-phenylene diacrylic acid Diethyl ester, polyvinyl cinnamate, polyphenoxy-isopropylcinnamylidene acetate, polyphenoxy-isopropyl α-cyanocinnamylidene acetate, naphthoquinone (1,2) diazide (2) -4-sulfonic acid Na salt, naphthoquinone (1, 2) Diazide (2) -5-sulfonic acid Na salt, naphthoquinone (1 , 2) diazide (2) -5-sulfonic acid ester (I), naphthoquinone (1,2) diazide (2) -5-sulfonic acid ester (II), naphthoquinone (1,2) diazide (2) -4- Sulfonate, 2,3,4,4′-tetrahydroxybenzophenone tri (naphthoquinonediazidesulfonic acid) ester, naphthoquinone-1,2,5- (trihydroxybenzophenone) triester, 1,4-iminoquinone-diazide (4 ) -2-sulfoamide (I), 1-diazo-2,5-diethoxy-4-p-trimercaptobenzene salt, 5-nitroacenaphthene, N-acetylamino-4-nitronaphthalene, organoboron compound, other than these Photoacid generators that generate cations by light, photobase generators that generate anions by light, and the like. But it is not limited to these. These can be used individually by 1 type or in combination of 2 or more type according to the characteristic of desired hardened | cured material.

(Ii) Monomer constituting the epoxy resin and polymerization initiator [monomer]
As the monomer constituting the epoxy resin, a compound having an epoxy group (hereinafter also referred to as “epoxy monomer”) is preferably used. For example, bisphenol A type epoxy monomer, bisphenol F type epoxy monomer, phenol novolac type epoxy monomer, novolak type epoxy monomer such as cresol novolak type epoxy monomer, alicyclic epoxy monomer, triglycidyl isocyanurate, nitrogen containing type such as hydantoin epoxy monomer Cyclic epoxy monomer, Hydrogenated bisphenol A type epoxy monomer, Hydrogenated bisphenol F type epoxy monomer, Aliphatic epoxy monomer, Glycidyl ether type epoxy monomer, Bisphenol S type epoxy monomer, Biphenyl type epoxy monomer, Dicyclocyclic type epoxy monomer, Naphthalene Type epoxy monomer. These can be used alone or in combination of two or more.

  In addition, even if it uses only an epoxy monomer as a monomer, you may use together the other kind of monomer which has a functional group which can be polymerized with the said epoxy monomer, but other kinds which have a functional group which can be polymerized with an epoxy monomer The combined use with the monomer is preferable. When only an epoxy monomer is used, a combination of a monofunctional monomer and a polyfunctional monomer is preferable as the epoxy monomer. When used in combination with other types of monomers that can be polymerized with the epoxy monomer, either a monofunctional monomer or a polyfunctional monomer may be used as the epoxy monomer.

  In the present specification, a monomer having both a (meth) acryloyl group and an epoxy group is referred to as a (meth) acrylate monomer for convenience.

[Curing agent]
As the curing agent for the epoxy monomer, known curing agents such as amine curing agents and acid anhydride curing agents can be used. Examples of the acid anhydride curing agent include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyl nadic anhydride, nadic anhydride, glutaric anhydride. An acid etc. are mentioned. A hardening | curing agent can be used individually by 1 type or in combination of 2 or more type according to the characteristic of desired hardened | cured material.

(Iii) Monomer constituting the silicone resin and polymerization initiator [monomer]
As the monomer constituting the silicone resin, a polymerizable silicone monomer is preferably used. Examples thereof include a silicone monomer having a functional group capable of polycondensation and hydrosilylation in the monomer, a radiation curable silicone monomer, and the like. Specifically, dimethyl silicone, methylphenyl silicone, amino group-containing silicone, carboxy group-containing silicone, carbinol group-containing silicone, phenyl group-containing silicone, organohydrogen silicone, polycyclic hydrocarbon-containing silicone, aromatic ring hydrocarbon Examples thereof include silicone monomers such as containing silicone and phenylsilsesquioxane. These can be used alone or in combination of two or more. Among these, a radiation curable silicone monomer is preferable.

  Although only the polymerizable silicone monomer may be used or another type of polymerizable monomer may be used in combination with the polymerizable silicone monomer, the combined use of the polymerizable silicone monomer and another type of polymerizable monomer is preferable.

  When only the polymerizable silicone monomer is used, a combination of a monofunctional polymerizable silicone monomer and a polyfunctional polymerizable silicone monomer is preferable. When the polymerizable silicone monomer is used in combination with another polymerizable monomer, only one of the monofunctional polymerizable silicone monomer and the polyfunctional polymerizable silicone monomer may be used. In the present specification, silicone having a (meth) acryloyl group is referred to as a polymerizable silicone monomer for convenience.

[Polymerization initiator]
A polycondensation reaction catalyst, a hydrosilylation reaction catalyst, a radiation curing polymerization initiator, and the like can be used depending on the type of monomer. A known catalyst can be used as the polycondensation reaction catalyst. Examples of the hydrosilylation reaction catalyst include aluminum compounds, platinum compounds, rhodium compounds, palladium compounds and the like. Examples of the radiation curing polymerization initiator include polymerization initiators used for the polymerization of the (meth) acrylate monomers. These can be used alone or in combination of two or more.

  In addition to the above monomers, radiation curable monomers having functional groups such as vinyl groups and acrylamide groups may also be included.

3.3. Dispersant The dispersion may contain a dispersant for dispersing the composite 10 or the like, if necessary. The dispersion may contain one or more known dispersants. As the dispersant used here, from the viewpoint of enhancing the dispersibility of the composite 10, an adsorption site for adsorbing on the surface of the composite 10 (forced ruxyl group, phosphorus-containing oxoacid group, sulfur-containing oxoacid group, etc.) It is preferable to have. Further, from the viewpoint of not reducing the refractive index and transparency, it is preferable that the dispersant itself has a high refractive index and is transparent. Examples of such a dispersant include a dispersant having a polymerizable functional group (polymerizable group) and an adsorption site (adsorptive group). For example, a polymerizable inorganic particle dispersant described in WO2013 / 047786 is preferably used. The entire contents described in WO2013 / 047786 are hereby incorporated by reference. In the composite 10, the coating layer 2 containing carboxylic acid present on the surface of the composite oxide particle 1 can also function as a dispersant.

3.4. Antioxidant The dispersion may contain a known antioxidant such as nitrogen or phosphorus from the viewpoint of imparting weather resistance. In that case, the content of the antioxidant in the dispersion is preferably 0.01% by mass or more, more preferably 1% by mass or more, more preferably 5% by mass or less, based on the composite 10. Preferably it is 4 mass% or less, More preferably, it is 3 mass% or less. When the content of the antioxidant in the dispersion is within the above-mentioned preferable numerical range, the coloration and deterioration tend to be suppressed for a long time, and the decrease in transparency and refractive index tends to be suppressed. is there.

3.5. Polymerization inhibitor The dispersion may contain a polymerization inhibitor. In that case, the content of the polymerization inhibitor in the dispersion is preferably 0.01% by mass or more, more preferably 1% by mass or more, more preferably 5% by mass or less, based on the composite 10. Preferably it is 4 mass% or less, More preferably, it is 3 mass% or less. When the content of the polymerization inhibitor in the dispersion is within the above-mentioned preferable numerical range, gelation in the dispersion tends to be easily prevented for a long period of time, and the decrease in transparency and refractive index is also suppressed. It tends to be easily done.

3.6. Others The dispersion may further contain a viscosity adjusting agent, a repelling agent, and the like from the viewpoint of improving viscosity and handling properties. In this case, those having excellent compatibility with the composite are preferably used.

3.7. Various Aspects of Dispersion The dispersion according to the present embodiment is not limited as long as the composite 10 is dispersed in a solvent. Specific embodiments include a dispersion containing the composite 10 in a solvent, a dispersion containing the composite 10 and a resin / monomer in a solvent, and optional components such as the composite 10 and the resin / monomer and a polymerization initiator. In a solvent, the dispersion liquid etc. are mentioned, However It does not specifically limit.

3.8. Physical Properties of Dispersion From the viewpoint of obtaining an optical material excellent in transparency, the dispersion of the present embodiment preferably has a transmittance of 50% or more at a measurement wavelength of 550 nm and an optical path length of 1 cm. Is 60% or more, more preferably 65% or more. Here, in this application, a transmittance | permeability shall be a value when the dispersion liquid with which solid content concentration of the composite_body | complex 10 was prepared to 10 mass% or more was used. High refractive index materials are required to have a higher refractive index, but to increase the refractive index using hybrid materials, it is necessary to increase the content of complex oxides having a higher refractive index than organic materials. . Examples of the hybridization method include a method in which the composite 10 is directly added to and dispersed in an organic material, and a method in which a solvent dispersion in which the composite 10 is dispersed in a solvent in advance is dispersed in the organic material. Although the latter method, that is, the method using the solvent dispersion, there is a tendency that a highly transparent dispersion is easily obtained. Therefore, in order to obtain a hybrid material having a high refractive index, the solvent dispersion can contain the desired amount of the composite 10 in the hybrid material with a small amount of the solvent dispersion when the composite content is large. . Further, since the amount of the composite 10 in the solvent dispersion is large, the amount of the solvent is relatively small, which is advantageous because the solvent removal step for obtaining the hybrid material can be shortened. Therefore, the content of the composite 10 dispersed in a solvent is preferably 10% by mass or more, more preferably 20% by mass or more, and further preferably 30% by mass or more. On the other hand, the upper limit is not particularly limited, but if it is usually contained more than 50% by mass, gelation tends to occur in a solvent.

3.9. Method for Producing Dispersion The dispersion according to the present embodiment can be easily obtained by mixing the composite 10 and the solvent described above with the optional components described above as necessary and mixing them. Since the composite 10 of this embodiment has high dispersion performance, it is easy to produce a transparent dispersion in which the composite 10 is uniformly dispersed. A more uniform dispersion state can be obtained by adding the above-described dispersant as necessary. Here, after mixing, a dispersion step such as ultrasonic dispersion may be performed as necessary to disperse the composite 10 more uniformly. In addition, the mixing method of a dispersing agent may add a dispersing agent to the liquid mixture of the composite 10 and a solvent, after adding the composite 10 and a dispersing agent beforehand, and adding to a solvent.

  Although the content ratio of the composite 10 in the dispersion is not particularly limited, the solid content concentration of the composite 10 is preferably 0.1% by mass or more and 90% by mass or less, more preferably 0.1% by mass or more and 50% by mass. % Or less. By making the solid content concentration of the composite 10 within the above-mentioned preferable numerical range, the refractive index imparting effect is high, the dispersion stability of the composite 10 is high, and a dispersion excellent in transparency tends to be obtained.

4). Resin Composite The resin composite of this embodiment contains at least the composite 10 and a matrix resin or a precursor (monomer) of the matrix resin. As the matrix resin and its precursor used here, the resins / monomers described in the section of the dispersion can be preferably used. Moreover, the resin composite may contain the arbitrary components described in the section of the dispersion. The composite 10 described above can be mixed with a matrix resin or a precursor thereof, and the refractive index of the resin or the precursor can be easily increased by mixing the composite 10.

  The content ratio of the matrix resin and its precursor in the resin composite is not particularly limited, but from the viewpoint of enhancing the refractive index improving effect and enhancing the mechanical properties of the resulting resin composite, the solid content relative to the composite 10 In terms of conversion, it is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, and preferably 80% by mass or less.

  The manufacturing method of the resin composite mentioned above is not specifically limited. For example, the composite 10 can be easily obtained by adding the above-described optional components to the matrix resin and its precursor as necessary and mixing them. Since the composite 10 has high dispersion performance as described above, it is possible to easily obtain a resin composite. Moreover, a kneading | mixing process may be performed after mixing as needed after mixing, and the composite_body | complex 10 may be disperse | distributed more uniformly. Furthermore, a more uniform dispersion state can be obtained by adding the above-described dispersant as necessary.

  A preferred method for producing the resin composite is a wet method. The wet method here is, for example, a method in which a desired matrix resin is mixed in a dispersion obtained by dispersing the composite 10 or the like in a solvent by the above-described method, and finally the solvent is removed. According to such a wet method, since the matrix resin or its precursor can be made to act uniformly on the surface of the composite 10, for example, aggregation of the nano-sized composite 10 is suppressed, and the transparent dispersion state is maintained. Stabilization is also possible.

  The resin composite described above can be molded into an arbitrary shape. In order to obtain a cured resin composite material having a predetermined shape, for example, the aforementioned polymerization initiator or curing agent can be used. At this time, the content of the polymerization initiator is not particularly limited, but from the viewpoint of refractive index, mechanical strength, curability, compatibility, color suppression, etc., solid content conversion with respect to solid content other than the composite 10 in the resin composite Is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, further preferably 1% by mass or more, and preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably. Is 5% by mass or less.

In the molding of the resin composite, various known molding methods can be applied. For example, when forming and curing in the form of a film or a sheet, after forming a film using a known film forming method such as spin coating, bar coating, spray coating, roll coating, etc., irradiation with ultraviolet rays, heat, electron beam, etc. And can be cured by polymerization. Moreover, after pouring directly into a desired site | part using a dispenser etc., you may superpose | polymerize with an ultraviolet-ray etc. The curing method is not particularly limited, but curing by ultraviolet (UV) irradiation is suitable. In the case of UV irradiation, the ultraviolet lamp uses a high-pressure mercury lamp, a metal halide lamp, a xenon lamp, a UV-LED, etc., and the illuminance of ultraviolet rays is from the viewpoint of refractive index, mechanical strength, curability, compatibility, coloring suppression, etc. , 30~3000mW / cm ^2, accumulated light quantity is preferably cured by irradiation with 10 to 10000 mJ / cm ^2. At this time, these light irradiation or electron beam irradiation may be used in combination with infrared irradiation, hot air application, high-frequency heating, or the like.

5. Application of Composite 10 The composite 10 of the present embodiment has not only a high refractive index but also easy dispersion. Therefore, a dispersion, a hybrid composite, a resin composite, and an optical material using the same can easily contain a large amount of composite oxide particles 1 having a high refractive index. It is also possible to vary the amount. Therefore, the composite 10 according to the present embodiment has a wide range of optical members used in the visible light range, lens applications such as designing various optical characteristics by combining various optical characteristics, film applications, optical circuits, optical paths, and the like. It can be suitably used in various applications that require refractive index control. In particular, the composite 10 of the present embodiment is one of the most suitable materials for various optical members that are highly transparent in a wide wavelength range and that require a high refractive index. That is, forward scattering, reflection, condensing, etc. used in the display part of a flat panel display (FPD) such as a liquid crystal display (LCD), a plasma display panel (PDP), an electroluminescence display (EL), a surface electric field display (SED), etc. Ideal for functional films. The present invention can also be applied to optical transmission members such as optical fibers, light guide sheets, microarray lens sheets, prism sheets, Fresnel lenses, lenticular lenses, lens sheets, diffusion films, holographic substrates, and light control films.

  Furthermore, since the composite oxide particles 1 constituting the composite 10 of the present embodiment have a high dielectric constant, they are suitable as a dielectric for capacitors, for example. Specific embodiments of the capacitor dielectric are known to those skilled in the art (for example, Japanese Patent Application Laid-Open No. 2017-50346). That is, the composite 10 of this embodiment can be applied to a dielectric layer of a multilayer ceramic capacitor, for example.

6). Manufacturing method of sintered compact When applying the composite 10 of this embodiment to a dielectric material layer, it is preferable to make the said composite 10 into a sintered compact. That is, the method for manufacturing a sintered body according to the present embodiment includes a step of heating and sintering the composite 10. Unlike the prior art (patent document 1), the composite 10 of this embodiment does not contain a component (silica or the like) derived from a silane coupling agent. Moreover, the carboxylic acid which comprises the coating layer 2 is defatted and removed naturally at the time of manufacture of a sintered compact. Thus, the sintered compact with few impurities is obtained by heating and sintering the composite 10 of this embodiment. The heating temperature, heating atmosphere, and the like are not particularly limited, and may be the same as in the past. Moreover, you may sinter with additives, such as a sintering auxiliary agent.

  Hereinafter, the present invention will be specifically described with reference to examples and the like. In addition, the material, usage-amount, ratio, the processing content, processing procedure, etc. which are shown in the following Examples can be suitably changed unless it deviates from the meaning of this invention. Therefore, the present invention is not limited to the following examples.

1. Production of composite (Example 1)
First step: 288.4 g (0.91 mol) of barium hydroxide octahydrate (precursor containing element R) and 1253 ml of 2-methoxyethanol (oxygen-containing organic solvent) were added to a nitrogen-substituted flask and stirred for 10 minutes. did. Next, 1251 ml of benzyl alcohol (oxygen-containing organic solvent) and titanium isopropoxide (precursor containing element M) 166.5 g (0.59 mol) were added, and the mixture was stirred for 10 minutes. Next, 157 g (0.59 mol) of oleylamine (amines) was added and stirred for 10 minutes to obtain a reaction solution.

  Second step: The obtained reaction solution was transferred to an autoclave and heated from room temperature to 160 ° C. over 105 minutes to obtain a milky white slurry-like synthesis solution containing a solid content.

  Third step: 2.2 times (mass ratio) of methanol was added to the resulting milky white slurry-like synthetic solution, and the mixture was stirred. The liquid mixed with methanol was centrifuged to obtain a solid content (1) as a precipitate. To the obtained solid (1), 2.2 times (mass ratio) of methanol was again added and dispersed, and then centrifuged, and the solid (2) was deposited as a precipitate. Obtained. A solution containing 0.3% by mass of acrylic acid (solvent: methanol containing 0.1% by mass or less of water) was added to the solid content (2) to disperse the solid content (2), and then centrifuged. Separation was performed to obtain a solid content (3) obtained by coating the surface of the barium titanate particles with acrylic acid. Next, a mixed solvent (2-methoxyethanol / ethanol mass ratio of 2-methoxyethanol and ethanol) is added to the solid content (3) so that the concentration of the solid content (3) containing barium titanate is 5% by mass. 1/9) was added and dispersed, followed by centrifugation to remove precipitates. The obtained dispersion was concentrated and dried at 70 ° C. to obtain a composite of Example 1. Further, the average dispersed particle size was measured using the dispersion.

(Example 2)
A dispersion and a composite were prepared and obtained in the same manner as in Example 1 except that a solution containing 1% by mass of acrylic acid was used instead of the solution containing 0.3% by mass of acrylic acid. The average dispersed particle size of the dispersion was measured.

(Comparative Example 1)
First step and second step: In the same manner as in Example 1, a milky white slurry-like synthetic liquid containing a solid content was obtained.

Third step: 2.2 times (mass ratio) of methanol was added to the resulting milky white slurry-like synthetic solution, and the mixture was stirred. The liquid mixed with methanol was centrifuged to obtain a solid content (4) as a precipitate. The solid content (4) is further washed twice with methanol to remove impurities contained in the solid content (4) as much as possible without using an acid solution, and has a coating layer on the surface of the barium titanate particles. No solid (5) was obtained.
Next, a mixed solvent of 2-methoxyethanol and ethanol (2-methoxyethanol / ethanol mass ratio is 1/9) is added to the solid content (5) so that the concentration of the solid content (5) is 5% by mass. Then, after the solid content (5) was dispersed, centrifugation was performed to remove the precipitate. The obtained dispersion was concentrated and heated at 70 ° C. to obtain a composite of Comparative Example 1. Further, the average dispersed particle size was measured using the dispersion.

(Comparative Example 2)
First step and second step: In the same manner as in Example 1, a milky white slurry-like synthetic liquid containing a solid content was obtained.

  Third step: 2.2 times (mass ratio) of methanol was added to the resulting milky white slurry-like synthetic solution, and the mixture was stirred. The liquid mixed with methanol was centrifuged to obtain a solid content (6) as a precipitate. To the obtained solid content (6), 2.2 times the mass (mass ratio) of methanol was added again and dispersed, and then centrifuged to obtain solid content (7) as a precipitate. Obtained. A solution containing 5% by mass of acrylic acid (solvent: 50% by volume of water and 50% by volume of acetone) is added to the solid content (7) to disperse the solid content (7), and then centrifuged. The solid content (8) obtained by coating the surface of the barium titanate particles with acrylic acid was obtained. Next, after adding ethanol and dispersing the solid content (8) so that the concentration of the solid content (8) containing barium titanate is 5% by mass, the precipitate is removed by centrifugation. did. The obtained dispersion was concentrated and dried at 70 ° C. to obtain a composite of Comparative Example 2. Further, the average dispersed particle size was measured using the dispersion.

(Comparative Example 3)
First step and second step: In the same manner as in Example 1, a milky white slurry-like synthetic liquid containing a solid content was obtained.

  Third step: 2.2 times (mass ratio) of methanol was added to the resulting milky white slurry-like synthetic solution, and the mixture was stirred. The liquid in which methanol was mixed was centrifuged to obtain a solid (9) as a precipitate. To the obtained solid (9), 2.2 times (mass ratio) of methanol was added again and dispersed, and then centrifuged, and the solid (10) was obtained as a precipitate. Obtained. A solution containing 1N hydrochloric acid (solvent: water 100 mass) was added to the solid content (10) to disperse the solid content (10), followed by centrifugation to obtain a white solid content (11). Got. Next, the solid content (11) containing barium titanate is dispersed and washed by adding ethanol to the solid content (11) so that the concentration is 5% by mass, and centrifuged to remove the precipitate. did. The solid content (10) was dried at 70 ° C. to obtain composite oxide particles of Comparative Example 3 having no carboxylic acid coating layer on the surface.

2. Evaluation of composites About the obtained composite (or composite oxide particles), phase identification, elemental analysis by ICP, average crystallite diameter, BET specific surface area, presence / absence of coating layer containing acrylic acid, and coating layer in particles The ratio was measured, and the storage stability of the composite oxide particles in the atmosphere was evaluated. Each measurement condition and evaluation method are as follows. In addition, the measuring method of the average dispersion particle diameter D50 of the above-mentioned dispersion liquid is also as follows.

2.1. Phase identification Phase identification analysis of the crystal phase contained in the composite (or composite oxide particles) was performed by powder X-ray diffraction measurement (XRD measurement). The specifications of the apparatus for powder X-ray diffraction measurement are as shown in Tables 1 and 2 below.

2.2. Elemental analysis by ICP An aqueous solution of acid containing hydrofluoric acid is added to the composite (or composite oxide particles) and dissolved, and after dilution, an inductively coupled plasma emission spectrometer (ICP-AES, manufactured by Thermo Fisher Scientific, CAP7600) Measurement was performed using Du 0). From the obtained elemental analysis results, the molar ratio of Ba and Ti was calculated.

2.3. Average crystallite diameter The average crystallite diameter of the perovskite-type crystal phase contained in the composite (or composite oxide particles) is calculated from the half width of the crystallinity peak obtained by powder X-ray diffraction measurement (XRD measurement). Calculated from the formula. The specifications and measurement conditions of the powder X-ray diffraction measurement apparatus are as shown in Tables 1 and 2 above.

2.4. Average dispersed particle size D50
For the dispersion containing the composite (or composite oxide particles), the average of the composite (or composite oxide particles) is measured using a dynamic light scattering particle size distribution measuring device (SZ-100, manufactured by HORIBA, Ltd.). The dispersed particle size was measured.
Holder temperature: 25 ° C
Sample refractive index: 2.40 (barium titanate)

2.5. BET specific surface area The BET specific surface area was measured by the BET single-point method using a fully automatic powder specific surface area measuring device (AMS1000) manufactured by Ritsu Okura. An N ₂ / He mixed gas was used as the adsorption gas.

2.6. Confirmation of the presence or absence of a coating layer containing acrylic acid The volatile component when heated from room temperature to 600 ° C. at 10 ° C./min is measured by gas chromatography mass spectrometry to form a composite (or composite oxide particle). It was confirmed whether or not a coating layer containing acrylic acid was present.

2.7. Ratio of coating layer The ratio of the mass of the coating layer to the composite (or composite oxide particles) (coating layer / (total mass of composite oxide particles and coating layer) was measured using a thermogravimetric apparatus TGA-50H (Shimadzu Corporation). The weight loss when heated from room temperature to 600 ° C. and held at 5 ° C. at 10 ° C./min was defined as the mass of the coating layer.

2.8. Storage stability in the atmosphere The composite (or composite oxide particles) is left in the air for 7 days, and the amount of impurities (barium carbonate) produced in the barium titanate is measured by powder X-ray diffraction measurement (XRD measurement). It was measured. At this time, XRD measurement was performed by mixing a known amount of barium carbonate and barium titanate, a calibration curve was created from the integrated intensity ratio of the barium carbonate and barium titanate-derived peak, and the amount of barium carbonate was calculated.

  The evaluation results are shown in Table 3 below. Moreover, the powder X-ray-diffraction measurement result is shown about each composite_body | complex (or composite oxide particle) in FIGS.

As is clear from the results shown in Table 3, in Examples 1 and 2 in which a solid content was obtained by a predetermined solvothermal method, and then the solid content was treated with an acid solution of less than 5% by mass. Was able to bring the molar ratio (R / M) between the element R and the element M in the finally obtained composite closer to 1 which is ideal as a perovskite crystal. The reason for this is considered to be that impurities containing the element R (for example, BaCO ₃ ) can be appropriately removed from the solid content by washing with an acid solution of less than 5% by mass. Moreover, even when the composites according to Examples 1 and 2 were stored in the atmosphere for a long time, generation of impurities (BaCO ₃ ) was not confirmed. It is considered that the reaction with carbon dioxide in the atmosphere could be suppressed by coating the surface of the composite oxide particles with carboxylic acid. Furthermore, as is clear from the results shown in FIGS. 3 and 4, in Examples 1 and 2, the composite contained a perovskite crystal phase. The average crystallite diameter of the perovskite type crystal phase was as small as 10 nm or less.
On the other hand, in Comparative Example 1 in which solid content was obtained by a predetermined solvothermal method and then washed with methanol without using carboxylic acid, the moles of element R and element M in the finally obtained composite were Although the ratio (R / M) could be close to a certain value of 1 as a perovskite crystal, a large amount of impurities (BaCO ₃ ) was generated when stored in the atmosphere for a long time. In Comparative Example 1, since the coating layer does not exist on the surface of the composite oxide particle, it is considered that Ba on the particle surface reacted with carbon dioxide in the atmosphere. As is clear from the results shown in FIG. 5, also in Comparative Examples 1 and 2, the composite oxide powder contained a perovskite crystal phase. The average crystallite diameter of the perovskite type crystal phase was as small as 10 nm or less.
In Comparative Example 2 in which a solid content was obtained by a predetermined solvothermal method and then pickled with a 5 mass% acid solution, the element in the finally obtained composite oxide particles The molar ratio of R to element M (R / M) was far below 1 which is ideal as a perovskite crystal. This is probably because the acid component concentration of the acid solution was too large, and not only the impurities containing the element R but also the element R constituting the perovskite crystal phase were eluted from the solid content by pickling. As is clear from the results shown in FIG. 6, also in Comparative Examples 1 and 2, the composite oxide powder contained a perovskite crystal phase. The average crystallite diameter of the perovskite type crystal phase was as small as 10 nm or less.
Further, in Comparative Example 3 in which the solid content was obtained by a predetermined solvothermal method and then pickled with an inorganic acid, the perovskite type crystal could not be obtained. The reason for this is considered to be that not only the impurities containing the element R but also the element R constituting the perovskite crystal phase were eluted from the solid content by pickling with an inorganic acid.

  Even if the ratio of element R to element M (R / M) is set to 1 at the stage of charging the reaction solution, the molar ratio (R / M) in the finally obtained composite oxide particles is much less than 1. . That is, since the element M is more reactive than the element R, a large amount of oxide (such as titanium oxide) derived from the element M is generated in the composite oxide particles in addition to the target perovskite crystal phase. Subsequent washing operation or the like causes element R to fall off, and as a result, the ratio of element M is higher than element R. In this way, it is extremely difficult to bring the molar ratio (R / M) in the finally obtained particles close to the ideal 1 only by charging the initial elements R and M.

  In the above embodiment, Ba is used as the element R and Ti is used as the element M. However, the technique of the present disclosure can be applied to the case where an element other than Ba is used as the element R, or the element M other than Ti. Even when elements are used, it is considered that the same effect is exhibited from the viewpoint of reactivity. For example, the element R is at least one selected from the group consisting of Ba, Sr, Ca, Mg, Al, Pb, Co, and Zn, and the element M is from Ti, Zr, W, Nb, Hf, and Sn. It is considered that the same effect is exhibited when one or more selected from the group is adopted.

Claims (16)

A composite comprising composite oxide particles and a coating layer covering at least a part of the surface of the composite oxide particles,
The composite oxide particles include at least one element R selected from the group consisting of Ba, Sr, Ca, Mg, Al, Pb, Co and Zn, and a group consisting of Ti, Zr, W, Nb, Hf and Sn. And a perovskite crystal phase composed of the element R, the element M, and oxygen, and one or more elements M selected from
The molar ratio (R / M) between the element R and the element M in the composition of the entire composite oxide particle is 0.85 or more and 1.15 or less,
The coating layer includes a carboxylic acid;
Complex. The average crystallite diameter of the perovskite type crystal phase in the composite oxide particles is 1 nm or more and 10 nm or less.
The composite according to claim 1. The specific surface area is 50 m ² / g or more and 200 m ² / g or less,
The complex according to claim 1 or 2. The element R is one or more selected from the group consisting of Ba, Sr, Ca and Mg.
The complex according to any one of claims 1 to 3. The element M is at least one selected from the group consisting of Ti, Zr and Hf.
The composite_body | complex of any one of Claims 1-4. The carboxylic acid is at least one of acrylic acid and acetic acid,
The composite_body | complex of any one of Claims 1-5. A precursor containing one or more elements R selected from the group consisting of Ba, Sr, Ca, Mg, Al, Pb, Co and Zn, and a group consisting of Ti, Zr, W, Nb, Hf and Sn A precursor containing one or more elements M to be mixed so that the element R is in an excessive amount with respect to the composition of the perovskite crystal phase, thereby obtaining a reaction solution,
A second step of obtaining a solid having a perovskite crystal phase by subjecting the reaction solution to a solvothermal method, and
By contacting the solid content with a solution containing carboxylic acid, impurities containing the element R are removed from the surface of the solid content, and at least a part of the surface of the solid content is coated with a coating layer containing carboxylic acid. And the molar ratio (R / M) between the element R and the element M in the solid content is 0.85 or more and 1.15 or less, the third step,
A method for producing a composite comprising: The average crystallite diameter of the perovskite type crystal phase in the solid content is 1 nm or more and 10 nm or less,
The manufacturing method according to claim 7. Obtaining a composite having a specific surface area of 50 m ² / g to 200 m ² / g,
The manufacturing method of Claim 7 or 8. The element R is one or more selected from the group consisting of Ba, Sr, Ca and Mg.
The manufacturing method of any one of Claims 7-9. The element M is at least one selected from the group consisting of Ti, Zr and Hf.
The manufacturing method of any one of Claims 7-10. The carboxylic acid is at least one of acrylic acid and acetic acid,
The manufacturing method of any one of Claims 7-11. The solution containing the carboxylic acid contains the carboxylic acid, water, and an organic solvent;
The carboxylic acid is dissolved in both the water and the organic solvent,
The manufacturing method of any one of Claims 7-12. According to the amount of the element R contained in the solid content obtained by the second step,
Adjusting the mixing ratio of the carboxylic acid, the water and the organic solvent in the solution containing the carboxylic acid;
The manufacturing method according to claim 13. In the third step, after contacting the solid content and the solution containing the carboxylic acid, the solid content is further washed with alcohol, and the element R and the element in the solid content after washing with the alcohol The molar ratio (R / M) with M is 0.85 or more and 1.15 or less,
The manufacturing method of any one of Claims 7-14. A step of heating and sintering the composite obtained by the production method according to any one of claims 7 to 15,
A method for producing a sintered body.