JP2003252916A - Composite particle and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a composite particle of a single nucleus wherein a metallic oxide or a silicon dioxide having a size of ≤ several μm is coated with an organic polymer compound of any film thickness. <P>SOLUTION: A manufacturing method of the composite particle comprises treating a surface of a metallic oxide finely divided particle or a silicon dioxide finely divided particle with a coupling agent having a substituent group reactive with the finely divided particle and a vinyl group reactive with a monomer of an organic polymer, adding a surfactant having a vinyl group reactive with the monomer of the organic polymer thereto, polymerizing the surfactant with the monomer, and improving dispersion stability of resulting product in the polymerization reaction process to obtain the composite particle comprising the metallic oxide or the silicon dioxide as a first layer of the center and the organic polymer compound as a second layer of the outside. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a mononuclear composite particle coated with an organic polymer compound and a method for producing the same.

[0002]

2. Description of the Related Art There are many known examples of the technique for coating the surface of fine particles of several μm or more with an organic polymer compound. However, it is difficult to obtain mononuclear composite particles by coating fine particles of 1 μm to 5 nm of metal, metal oxide or silicon oxide with an organic polymer compound. This is because it is difficult to uniformly coat the surface of the particle core due to aggregation of particles and the like.

As a method for obtaining mononuclear fine particles, gold fine particles have been coated by a method of supporting a core gold particle with a film of porous alumina or the like and coating it with a polymer compound (Chem. Mater. 1998, 10, 1214.A
dv. Mater. 1999, 11, 34.).

Further, 100 nm size silver fine particles are coated by emulsion polymerization of silver fine particles with polystyrene or methacrylic acid in the presence of oleic acid (J. Am. Chem. Soc., 1999, 121, 10642. ).

Conventionally, as examples of coating inorganic oxide fine particles with an organic polymer, JP-A-9-325525 and JP-A-9-325525 have been proposed.
311504, JP-A-9-31105,
As described in JP-A-9-325524, when the inorganic oxide fine particles are dispersed together with a monomer and polymerized,
Inorganic oxide particles are treated by a method of treating the inorganic oxide particles with a silane-based or titanate-based coupling agent, or by dispersing the inorganic particles in a solvent containing a surfactant and adsorbing the surfactant on the particle surface. An example is known in which fine particles of an inorganic oxide having a high affinity with an organic substance are used.

[0006]

In the method of supporting gold particles as cores with a film of porous alumina or the like and coating them with a polymer compound, the size of the cores and composite particles is limited by the size of the pores of the film. However, there are drawbacks such as that it takes time and effort because it is necessary to support the fine particles on the membrane one by one and dissolve the membrane.

In the method of emulsion-polymerizing fine silver particles with polystyrene or methacrylic acid in the presence of oleic acid, at present, only a film thickness of 2-10 nm is coated, and when the film thickness of the polymer compound to be coated is increased. (> 10 nm) It becomes difficult to obtain fine particles having a spherical shape, and the number of polynuclear fine particles increases.

In the examples of the prior art in which the inorganic oxide fine particles are coated with the organic polymer, particles obtained by dispersing the inorganic oxide fine particles in the resin are obtained by any method.
It is not possible to obtain mononuclear composite particles having a layered structure.

The object of the present invention is to provide a metal oxide or silicon oxide fine particle having an arbitrary size of 1 μm to 5 nm, particularly in the above-mentioned situation, without depending on the support by a membrane such as porous alumina. This is to obtain mononuclear composite particles in which fine particles of silicon oxide are coated with an organic polymer compound having an arbitrary thickness.

[0010]

Means for Solving the Problems The present invention was obtained as a result of extensive studies on a method for synthesizing metal oxide fine particles and a polymerizing method.

The characteristic is that the surface of the metal oxide fine particles or silicon oxide fine particles is coated with an organic polymer compound by the vinyl group polymerization reaction of the metal oxide fine particles or silicon oxide fine particles of the first layer as the center. In doing so, the surface of the metal oxide fine particles or the silicon oxide fine particles is treated with a coupling agent having a substituent capable of reacting with the fine particles and a vinyl group capable of reacting with the monomer of the organic polymer, and the By adding a surfactant having a vinyl group capable of reacting with the monomer and polymerizing the monomer together with the monomer, the dispersion stability is enhanced in the polymerization reaction process, thereby forming a two-layer structure composed of two different substances. It is possible to obtain a composite particle characterized in that the central first layer is a metal oxide or silicon oxide and the outer second layer is an organic polymer compound. In the Rukoto. At this time, the coupling agent and the surfactant are not considered further. In the present invention, it is possible to obtain composite particles in which the surface of metal oxide fine particles or silicon oxide fine particles having a particle diameter of 1 μm to 5 nm is coated with an organic polymer compound having a film thickness of 5 μm to 5 nm.

When the surface of metal oxide fine particles or silicon oxide fine particles is coated with an organic polymer compound, the fine particle surface is treated with a silane coupling agent or a surfactant to improve the affinity with organic substances. Even if the organic polymer monomer is used for the polymerization reaction, a composite particle having a two-layer structure cannot be obtained in good yield.

It is important that the coupling agent has a substituent capable of reacting with the metal oxide fine particles or the silicon oxide fine particles and a substituent capable of reacting with the monomer forming the organic polymer layer. is there. Specifically, a silylalkoxyl group or SiOH group that reacts with -OH groups of metal oxide fine particles or silicon oxide fine particles and a vinyl group (H ₂ C = CH-R-SiR ' _m (OH )
_3-m R ′: OCH ₃ , OC ₂ H ₅ , OC ₃ H ₇ , OC ₃ H ₇ ,
OC ₄ H ₉ m = 3,2,1 R is not particularly limited). It is also possible to replace silicon with another metal element such as titanium.

It is important that the surfactant has a substituent capable of reacting with the monomer forming the organic polymer layer. Specifically, an anionic or cationic surfactant can be used, but it is necessary to have a vinyl group. For example sulfonic acid having a vinyl group and a salt thereof _{(H 2 C = CH-R} "-SO 3 X · xH 2 O X:
R ″ is not particularly limited as long as it is H, Li, K, Na). In the examples, 4-styrenesulfonic acid sodium salt (H ₂ C ═CHC ₆ H ₄ SO ₃ Na · xH ₂ O) is used. .

The metal oxide or silicon oxide of the first layer is formed by a hydrolytic condensation reaction of a metal or silicon alkoxy compound, a metal or silicon halide, a metal salt or a metal chelate, and an -OH group is formed on the surface of the fine particles. It is necessary to have. At this time, coating with an organic polymer compound can be performed using composite particles having a metal, a metal oxide, and a silicon oxide in the particles of the metal oxide or the silicon oxide of the first layer. The following examples are known for coating metal particles with silicon or titanium oxide (Adv. Mater. 2001, 13, 11., Langmuir 2000, 16,).
2713.). In addition, composite particles having silicon oxide in titanium oxide particles are also known as follows (Langmuir
1999, 15, 5535.). In the present invention, this method may be applied to perform coating with an organic polymer compound using composite particles having a metal, a metal oxide, and a silicon oxide in the particles of the metal oxide or the silicon oxide of the first layer. it can.

The precursor compound for forming the metal oxide or silicon oxide of the present invention is not limited as long as it is a compound that can finally become a metal oxide. One or more selected from the group consisting of metal alkoxides, metal acetylacetonates, metal carboxylates and metal chelates are preferred. Examples of the metal or silicon alkoxide include Si, Ge, Sn, Pb, Al, Ga, As and S.
b, Bi, Ti, Zr, V, Nb, Ta, Na, K, L
Examples thereof include alkoxides such as i, Ca, Mg, Ba and Sr. Specific examples include the following. L
_{iOCH 3, NaOCH 3, Cu (} OCH 3) 2, Ca (OCH 3) 2
, Sr (OC ₂ H ₅ ) ₂ , Ba (OC ₂ H ₅ ) ₂ , Zn (OC _{2
H 5) 2, B (OCH} 3) 3, Al (i-OC 3 H 7) 3, Ga
_{(OC 2 H 5) 3,} Y (OC 4 H 9) 3, Ge (OC 2 H 5) 4, Pb
(OC ₄ H ₉ ) ₄ , P (OCH ₃ ) ₃ , Sb (OC ₂ H ₅ ) ₃ , V
O (OC ₂ H ₅ ) ₃ , Ta (OC ₃ H ₇ ) ₅ , W (OC ₂ H ₅ ) ₆ ,
La (OC ₃ H ₇ ) ₃ , Nd (OC ₂ H ₅ ) ₃ , Si (OCH ₃ ) ₄
, Si (OC ₂ H ₅ ) ₄ , Si (i-OC ₃ H ₇ ) ₄ , Si (t
_{-OC 4 H 9) 4, Ti} (OCH 3) 4, Ti (OC 2 H 5) 4, Ti
_{(i-OC 3 H 7)} 4, Ti (OC 4 H 9) 4, Zr (OCH 3) 4,
Zr (OC ₂ H ₅ ) ₄ , Zr (OC ₃ H ₇ ) ₄ , Zr (OC ₄ H ₉ ) ₄
, Al (OCH ₃ ) ₃ , Al (OC ₂ H ₅ ) ₃ , Al (i-OC
₃ H ₇ ) ₃ , Al (OC ₄ H ₉ ) ₃ , La [Al (iso-OC
_{3 H 7) 4] 3,} Mg [Al (iso-OC 3 H 7) 4] 2, M
_{g [Al (sec-OC 4} H 9) 4] 2, Ni (iso-OC 3 H
₇ ) ₄ ] ₂ , (C ₃ H ₇ O) ₂ Zr [Al (OC ₃ H ₇ ) ₄ ] ₂ , B
a [Zr ₂ (OC ₂ H ₅ ) ₉ ] ₂ or the like can be used.

As the metal chelate compound, those having a 1,3-dicarbonyl compound such as acetylacetonate as a ligand are used, and specific examples include the following. Tris (acetylacetonato) aluminum, tris (ethylacetoacetato) aluminum, tris (salicylaldehyde) aluminum, indium acetylacetonate, zinc acetylacetonate, copper acetylacetonate, platinum acetylacetonate, etc. can be used. .

As the metal carboxylate, for example, acetate or the like is used, and specific examples include the following. Barium acetate, copper (II) acetate, lithium acetate, magnesium acetate, lead acetate, barium oxalate, calcium oxalate, copper (II) oxalate, magnesium oxalate,
Tin (II) oxalate, yttrium oxalate, yttrium stearate, etc. can be used.

As the metal or silicon halide,
TiCl ₄ , ZnCl ₂ , WCl ₆ , SnCl ₂ , Sr
Cl ₆ , SiCl _4, etc. can be used.

The organic polymer compound in the second layer of the composite particles having a two-layer structure composed of two different substances is not particularly limited as long as it is based on the polymerization of vinyl group, and it is ionic polymerization or radical. Polymerization can be used. The reaction for forming the metal oxide or silicon oxide of the present invention is preferably carried out in a water or alcohol solvent. Therefore, it is desirable that the subsequent coating reaction of the second layer with the organic polymer compound is also performed in the same solvent. In this case, it is preferable to use a polymer compound obtained by polymerizing a monomer having a high radical polymerization activity such as a polystyrene derivative, a poly (meth) acrylate, or a polyvinyl acetate derivative shown below. The styrene derivative monomer used for the polymerization of the thermoplastic resin,
Although not particularly limited, examples thereof include styrene, α-methylstyrene, p-methylstyrene, and p-chlorostyrene, and these can be used alone or in combination of two or more kinds. Other monomers used for the polymerization of the thermoplastic resin are not particularly limited, but include, for example, (meth) acrylate, vinyl acetate, vinyl esters such as vinyl propionate, unsaturated nitriles such as acrylonitrile and methacrylonitrile, and acryl. Acid and methacrylic acid are mentioned. These may be used alone or in combination of two or more.

In the present invention, the thickness of the organic polymer compound in the second layer can be controlled by changing the monomer concentration at the start of the reaction or by re-adding the monomer and the initiator during the polymerization. .

The composite particles of the present invention can also be used as a photonic crystal material. In a substance having a periodic refractive index change similar to the wavelength of light inside, the light wave undergoes Bragg reflection due to the periodic refractive index distribution, and a photo band gap (PBG) appears. Since the propagation of light in a photonic crystal is determined by the band structure, it is possible to freely design its optical properties by controlling the crystal structure and the magnitude of periodic perturbations. It can be applied as a basic structure for forming various optical devices such as lasers used for optical transmission, optical waveguides, and optical integrated circuits.

At present, the formation of three-dimensional photonic crystals using the self-organization of fine particles of polystyrene or silica, which is a polymer material, or the mechanical arrangement method is known. (Jpn. J. Ap
pl.Phys. 37, (1998) L508. Appl. Phys. Lett. 71, 114
8. Jpn. J. Appl. Phys. 37, L1527. Appl. Phys. Lett.
72, 1957. Appl. Phys. Lett. 75, 932. AdvancedRobo
tics.11, 169. J. Lightwave Technol. 17, 1956. Adva
nced Robotics. 11,169.) However, the method using self-assembly of fine particles has an advantage that it can be easily formed.
It has the drawback that it is difficult to implement G. In order to realize a complete PBG, it is necessary to arrange the particles with a constant spacing.

By arranging the fine particles of the present invention two-dimensionally or three-dimensionally, the central particle spacing can be controlled by the film thickness of the second layer covering the particles, and a perfect PBG can be expected as a photonic crystal material. Can be used.

When used as a photonic crystal, in a composite particle having a two-layer structure composed of two different substances, it is desirable that the difference in refractive index between the central first layer and the outer second layer is large, and the outer first layer is large. It is desirable to use a polymer compound having a large difference in refractive index from air for the two layers. Also,
The first layer of the central nucleus is preferably made of a material having a small light absorption such as a metal oxide rather than a particle having a large light absorption such as a metal particle.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION An outline of a method for producing composite particles of the present invention will be described with reference to FIG. The inorganic oxide particles 1 of the first layer, which serves as the center, are formed by the hydrolysis and condensation reaction of an alkoxy compound of metal or silicon, a silicon halide, a metal salt, and a metal chelate. At this time, the surface of the formed inorganic oxide particles 1 has —OH groups. Next, with a coupling agent 2 having an alkoxyl group or a hydroxyl group capable of reacting with the —OH group on the surface of the obtained inorganic oxide particles 1 and a vinyl group capable of reacting with a monomer forming an organic polymer. The inorganic oxide particles 1 to which the coupling agent 2 has been added are formed by the treatment. Next, to the obtained inorganic oxide particles 1, a surfactant 3 having a vinyl group capable of reacting with a monomer forming an organic polymer is added together with a monomer 4 forming an organic polymer to carry out a polymerization reaction. Let Thereby, mononuclear composite particles obtained by coating the surface of the inorganic oxide particles 1 with the organic polymer compound 6 as shown in FIG. 1 can be obtained.

Examples of producing composite particles of the present invention will be described below.

Example 1 (first layer: gold-encapsulating SiO ₂ ,
Second layer: polymethacrylic acid) 80 mL of an aqueous solution of chloroauric acid (HAuCl ₄ ) 2.4 × 10 ^-4 mol / L and sodium citrate 1.6 × 10 ^-3 mol / L is reacted at 80 ° C. for 40 minutes. Gold fine particles were obtained. Next, to 1251 g of the gold fine particles synthesized above, 0.125 g of tetraethoxysilane (Si (OEt) ₄ ), 0.9 g of 25% NH ₃ aqueous solution and 19.58 g of ethanol were added and reacted at 35 ° C. for 5 hours. To obtain fine particles coated with silicon oxide. After bubbling the obtained gold-silicon oxide composite particle reaction solution with nitrogen, a silane coupling agent (CH
_{2 = CCH 3 COOC 3 H 6} Si (OCH 3) 3) 0.005g
Was added and stirred at 35 ° C. for 30 minutes, then 0.027 g of a 5% surfactant solution (CH ₂ ═CHC ₆ H ₄ SO ₃ Na), a reaction initiator: 5% potassium persulfate solution (K ₂ S ₂ O ₈ ) 0.61g
, 0.29 g of methyl methacrylate was added, and the mixture was added at 70 ° C for 12
Composite particles were obtained by reacting for a time.

[Example 2] (First layer: gold-encapsulating SiO ₂ ,
Second layer: polystyrene) gold was produced in the same manner as in Example 1 - after the silicon oxide composite particles reaction solution was bubbled nitrogen, silane coupling agent _{(CH 2 = CCH 3 COOC 3} H 6 Si (OC
H ₃ ) ₃ ) 0.005 g was added and the mixture was stirred at 35 ° C. for 30 minutes and then a 5% surfactant solution (CH ₂ ═CHC ₆ H ₄ SO ₃ N
a) 0.027 g, reaction initiator: 5% potassium persulfate solution (K ₂ S ₂ O ₈ ) 0.61 g, and p-styrene 0.3 g were added and reacted at 70 ° C. for 12 hours to obtain composite particles.

[Example 3] (first layer: SiO ₂ , second layer: polymethacrylic acid) tetraethoxysilane (Si (OEt) ₄ ) 0.2 mol / L,
Water 11 mol / L, NH ₃ 0.2 mol / L ethanol solution 3
0 mL was reacted at 35 ° C. for 12 hours to obtain silicon oxide fine particles. 3 mL of the obtained silicon oxide fine particle reaction solution was centrifuged, the solvent was replaced with a mixed solvent (ethanol 75.3 wt%, pure water 24.7 wt%) to 30 mL, and the mixture was re-dispersed by ultrasonic irradiation. Composite particles were obtained by reacting with methyl methacrylate in the same manner as in Example 1.

[Example 4] (First layer: SiO ₂ , second layer: polystyrene) 3 mL of the reaction solution of silicon oxide fine particles obtained by the same method as in Example 3 was centrifuged and mixed solvent (ethanol 75 Replace the solvent with 0.3 wt% and pure water 24.7 wt% 3
The volume was adjusted to 0 mL and redispersed by ultrasonic irradiation. Composite particles were obtained by reacting with p-styrene in the same manner as in Example 2.

Example 5 (First layer: TiO ₂ , second layer: polymethacrylic acid) Tetraethoxy titanium (Ti (OEt) ₄ ) 0.1 mol / L
Water was added to 60 mL of ethanol solution at a concentration of 0.5 mol / L and hydroxypropyl cellulose (dispersion stabilizer) at 0.5 g / L, and the mixture was refluxed for 1 hour to obtain titanium oxide particles. The obtained titanium oxide fine particles were separated with a centrifugal separator and washed with pure water. Mixed solvent (ethanol 75.3 wt%, pure water 24.7 wt) in the obtained titanium oxide fine particles.
%) To replace the solvent to 150 mL, and redisperse by ultrasonic irradiation. The obtained titanium oxide ethanol solution 30
mL was reacted with methyl methacrylate in the same manner as in Example 1 to obtain composite particles.

Example 6 (First Layer: TiO ₂ , Second Layer: Polystyrene) 18 mL of ethanol was added to 12 mL of an ethanol solution of titanium oxide fine particles obtained by the same method as in Example 5, and Example 2 was used. In the same manner as described above, a composite particle was obtained by reacting with p-styrene.

[Example 7] (First layer: SiO ₂ , second layer: polystyrene) 3 mL of a reaction solution of fine particles of silicon oxide obtained in the same manner as in Example 3 was centrifuged to obtain a mixed solvent (ethanol 7).
The solvent is replaced with 5.3 wt% and pure water 24.7 wt% 30
It was made up to mL and redispersed by ultrasonic irradiation. Silane coupling agent (CH ₂ = CCH ₃ COOC ₃ H ₆ Si (OC
H ₃ ) ₃ ) 0.007 g was added and stirred at 35 ° C. for 30 minutes,
5% surfactant solution (CH ₂ = CHC ₆ H ₄ SO ₃ Na)
0.041 g, a reaction initiator: 0.94 g of a 5% potassium persulfate solution (K ₂ S ₂ O ₈ ) and 0.45 g of p-styrene were added and reacted at 70 ° C. for 12 hours to obtain composite particles.

[Example 8] (First layer: SiO ₂ , second layer: polystyrene) 3 mL of a reaction solution of silicon oxide fine particles obtained in the same manner as in Example 3 was centrifuged to obtain a mixed solvent (ethanol 7).
The solvent is replaced with 5.3 wt% and pure water 24.7 wt% 30
It was made up to mL and redispersed by ultrasonic irradiation. Silane coupling agent (CH ₂ = CCH ₃ COOC ₃ H ₆ Si (OC
H _{3) 3)} 0.015g was reacted 30 minutes at 35 ° C. added. 5% surfactant solution (CH ₂ = CHC ₆ H ₄ SO ₃
Na) 0.084 g, reaction initiator: 5% potassium persulfate solution (K ₂ S ₂ O ₈ ) 1.92 g, p-styrene 0.93 g
Was added and reacted at 70 ° C. for 12 hours to obtain composite particles.

Comparative Example 1 (using silane coupling agent, no surfactant) Tetraethoxysilane (Si (OEt) ₄ ) 0.2 mol / L,
Water 11 mol / L, NH ₃ 0.2 mol / L ethanol solution 3
0 mL was reacted at 35 ° C. for 12 hours to obtain silicon oxide fine particles. 3 mL of the obtained silicon oxide fine particle reaction solution was centrifuged, the solvent was replaced with a mixed solvent (ethanol 75.3 wt%, pure water 24.7 wt%) to 30 mL, and the mixture was re-dispersed by ultrasonic irradiation. Silane coupling agent (CH
_{2 = CCH 3 COOC 3 H 6} Si (OCH 3) 3) 0.005g
Was added and stirred at 35 ° C. for 30 minutes, and then a reaction initiator: 5% potassium persulfate solution (K ₂ S ₂ O ₈ ) 0.61 g and p-styrene 0.3 g were added and reacted at 70 ° C. for 12 hours. . 70
The reaction was performed at 12 ° C for 12 hours. The resultant particles were mostly grain seedless containing no particles or SiO ₂ particles Fukukaku including a large number of SiO ₂ particles, particles of mononuclear containing SiO ₂ particles was not obtained.

[Comparative Example 2] (without silane coupling agent, using surfactant not having vinyl group) Tetraethoxysilane (Si (OEt) ₄ ) 0.2 mol / L,
Water 11 mol / L, NH ₃ 0.2 mol / L ethanol solution 3
0 mL was reacted at 35 ° C. for 12 hours to obtain silicon oxide fine particles. 3 mL of the obtained silicon oxide fine particle reaction solution was centrifuged, the solvent was replaced with a mixed solvent (ethanol 75.3 wt%, pure water 24.7 wt%) to 30 mL, and the mixture was re-dispersed by ultrasonic irradiation. 5% surfactant solution (C ₂ H ₅ C ₆
H ₄ SO ₃ Na) 0.027 g was added and stirred at 35 ° C. for 30 minutes,
Reaction initiator: 5% potassium persulfate solution (K ₂ S ₂ O ₈ ) 0.
61 g and 0.3 g of p-styrene were added and reacted at 70 ° C. for 12 hours. Particles of Fukukaku resulting particles containing a large number of SiO ₂ particles, particles seedless without the SiO ₂ particles or SiO ₂ particles, are mostly particles of mononuclear containing SiO ₂ particles was not obtained.

Comparative Example 3 (without silane coupling agent, used before surfactant polymerization reaction) Tetraethoxysilane (Si (OEt) ₄ ) 0.2 mol / L,
Water 11 mol / L, NH ₃ 0.2 mol / L ethanol solution 3
0 mL was reacted at 35 ° C. for 12 hours to obtain silicon oxide fine particles. 3 mL of the obtained silicon oxide fine particle reaction solution was centrifuged, the solvent was replaced with a mixed solvent (ethanol 75.3 wt%, pure water 24.7 wt%) to 30 mL, and the mixture was re-dispersed by ultrasonic irradiation. 5% surfactant solution (CH ₂
= CHC ₆ H ₄ SO ₃ Na) 0.027 g, and added at 35 ° C. for 30
After stirring for a minute, 0.61 g of a reaction initiator: 5% potassium persulfate solution (K ₂ S ₂ O ₈ ) and 0.3 g of p-styrene were added and the reaction was carried out at 70 ° C. for 12 hours. The obtained particles are SiO
Particles of Fukukaku containing ₂ particles, most particles seedless without the SiO ₂ particles in all particles, the proportion of mononuclear particles containing SiO ₂ particles was 3%.

Table 1 shows the morphology of the composite particles produced in Examples 1-8.

The particle size and particle size distribution of the produced particles can be measured by
A small amount of the reaction solution before and after the coating was sampled and subjected to a transmission electron microscope. The particle size distribution was obtained by measuring the particle size of 200 or more particles for each sample, and the dispersity (C _V ) was calculated by the following formula.

[0041]

[Equation 1]

As shown in Table 1, in Example 2 using polystyrene as compared with Example 1 using methyl methacrylate, composite particles having a small degree of dispersion can be obtained. Similarly, composite particles having a smaller degree of dispersion can be obtained in the case of 6 and 6 than in the example 3.

When used as a photonic crystal, it is desirable that the difference in refractive index between the first layer in the center and the second layer on the outside is large, and 4 or 5 is more desirable than in Example 2 or 3.

As shown in Examples 7 and 8, the particle size can be controlled by changing the reagent concentration at the start of the reaction.

[0045]

[Table 1]

The composite particles of the present invention are used for various preparations such as agricultural chemicals, medicines, fertilizers, sustained-release preparations thereof, coating agents for fishing nets, seaweed cultivation nets, ship bottom paints, and other small animals sown in sandboxes such as parks. Sustained release repellent, as well as paints, inks, toners, adhesives, paper lamination, foamed resin materials,
It can be widely used for applications such as extinguishing agents, cosmetic materials, civil engineering materials, and optical materials such as fatonic crystals.

[0047]

According to the present invention, mononuclear composite particles in which a metal oxide or a silicon oxide having a size of several μm or less is coated with an organic polymer compound to an arbitrary thickness can be efficiently produced.

[Brief description of drawings]

FIG. 1 is a diagram showing a method for producing composite particles of the present invention.

[Explanation of symbols]

1 ... Inorganic oxide particles, 2, 5 ... Coupling agent, 3 ... Surfactant, 4 ... Organic polymer monomer, 6 ... Organic polymer compound.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshiya Sato             7-1-1, Omika-cho, Hitachi-shi, Ibaraki Prefecture             Inside the Hitachi Research Laboratory, Hitachi Ltd. (72) Inventor Takao Miwa             7-1-1, Omika-cho, Hitachi-shi, Ibaraki Prefecture             Inside the Hitachi Research Laboratory, Hitachi Ltd. (72) Inventor Mikio Konno             07 Aoba, Aramaki, Aoba-ku, Sendai-shi, Miyagi Prefecture (72) Inventor             07 Aoba, Aramaki, Aoba-ku, Sendai-shi, Miyagi Prefecture F-term (reference) 4J011 CA05 PA04 PA07 PA13 PB06                 4J100 AB02P AJ02P CA01

Claims (11)

[Claims] 1. A composite particle having a two-layer structure composed of two different substances, wherein a central first layer has a spherical shape and a metal oxide or silicon oxide having a particle size of 5 nm to 1 μm and an outer second layer. Layer is spherical and has a thickness of 5 nm to 5 μm, which is an organic polymer compound. 2. A composite particle having a two-layer structure composed of two different substances, wherein the first central layer has a metal oxide or silicon oxide and the second outer layer has a vinyl group. Composite particles characterized by being an organic polymer compound produced by anion, cation or radical polymerization of the body. 3. An organic polymer compound produced by anion, cation or radical polymerization of a metal oxide or silicon oxide and a vinyl group-containing monomer coated on the surface of the metal oxide or silicon oxide particles. And a composite particle. 4. The composite particle according to claim 1, wherein the metal oxide or the silicon oxide has a particle size of 5 nm to 1 μm. 5. The composite particle according to claim 1, wherein the organic polymer compound has a film thickness of 5 nm to 5 μm.
m is a composite particle. 6. The composite particle according to claim 1, wherein the second layer is polystyrene. 7. The composite particle according to claim 1 or 2, wherein the central first layer is titanium oxide. 8. The composite particle according to claim 1, wherein the central first layer is titanium oxide and the second layer is polystyrene. 9. The composite particle according to claim 1 or 2, wherein the central first layer contains particles of a metal, a metal oxide or a silicon oxide. 10. The composite particle according to claim 9, wherein the second layer is polystyrene. 11. An alkoxy compound of metal or silicon,
The step of forming the fine particles of the first layer, which is the core, by the hydrolytic condensation reaction of silicon halide, metal salt, and metal chelate, the substituent capable of reacting the formed fine particle surface with the fine particles, and the organic high-layer coating for the fine particle surface. The step of treating with a coupling agent having a substituent capable of reacting with the monomer forming the molecular layer, and adding a surfactant having a substituent capable of reacting with the monomer, and polymerizing with the monomer A method for producing composite particles, which comprises a step of reacting.