JP2000034582A - Composite particle and hollow particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite particle preferably used in electronic materials, electrically conductive materials, magnetic materials, catalysts, pharmaceuticals, diagnostic agents or the like and a method for preparing the same, and to provide a hollow particle possibly used in optical materials, microcapsule materials, shielding materials, filling materials, electrically conductive materials, catalysts or the like and a method for preparing the same. SOLUTION: The spherical polymer particle-metal compound composite particle has a structure that (1) at least one kind of metal fine particles selected from metal iron and metal copper or (2) at least one kind of metal compound fine particles selected from iron oxide, basic copper carbonate and copper oxide are adsorbed on the surface of a spherical polymer particle by aggregation. The spherical hollow particle has a particle size of 0.04-50 μm and inner pores and is composed of at least one metal compound selected from metal iron, iron oxide, metal copper, basic copper carbonate and copper oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to composite particles suitably used for electronic materials, conductive materials, magnetic materials, catalysts, medicines, diagnostic agents, etc. and a method for producing the same, as well as optical materials, microcapsule materials, concealing materials, The present invention relates to hollow particles that can be used as a filling material, a conductive material, a catalyst, and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Polymer particles having a narrow particle size distribution and the like are used as standard particles, carrier particles for diagnostic agents, particles used in lubricants and the like. However, for example, when used as standard particles and lubricants, since the strength of these particles is weak, under the conditions of shear or high temperature, there are cases where the particles are deformed or collapsed, and the inherent properties cannot be utilized,
The range of use is very limited. In order to improve these drawbacks, for example, a method of copolymerizing a crosslinkable monomer or the like with the compound to form a highly crosslinked body has been proposed, but it is still not sufficient because the polymer is basically a polymer. . In addition, the above-mentioned particles have been applied for diagnostic drugs, pharmaceuticals, etc., but there are limitations on the affinity for antigens and antibodies, biocompatibility, etc.
There is a disadvantage that the range of application is limited.

On the other hand, many kinds of metal compound particles are used for ceramics such as electronic materials, magnetic materials, optical materials, heat-resistant materials, and strength materials. Various composite particles have been proposed in order to respond to the development. For example, by coating iron oxide particles with a silicon compound, heat treatment is performed to prevent shape collapse and sintering between magnetic materials when producing needle-like magnetic materials, and iron powder is coated with copper. In addition, there have been reports of a material intended to increase the strength as a powder metallurgy material, and a material intended to increase heat resistance by coating yellow iron oxide particles with antimony and aluminum oxide. However, most of these are composite particles of metal compounds, which cannot sufficiently cope with versatility of applications, and the development of composite particles capable of expressing various functions is particularly required for electronic materials, optical materials, and the like. Was.

[0004]

As described above, the copolymer particles have excellent heat resistance, toughness, light resistance, and abrasion resistance because they are polymers, although they have very excellent performance. In addition, the controllability of biocompatibility and affinity of the particle surface to antigens and antibodies is limited, and the appearance of composite particles in which the particle surface is coated with a metal compound has been expected. Of course, in other applications of polymer particles, for example, applications such as concealing materials, lubricants, column fillers, and standard particles, it has been desired to modify the particle surface with a metal compound having performance different from that of the polymer.

On the other hand, in applications such as electronic materials, conductive materials, magnetic materials, and optical materials, it has been desired to develop a composite material in which core particles made of a non-conductive material are coated with a conductive material.

Further, hollow particles of metal and metal compounds are being used for applications such as catalysts and microcapsules, and it has been desired that the particles have magnetism and conductivity.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above circumstances, and as a result, it has been found that composite particles or hollow particles having a specific composition and a specific particle diameter, which will be described later, achieve the above object. The inventors have found that the present invention has been completed.

That is, the present invention provides a spherical polymer characterized in that (a) the core is a polymer, and (b) the shell is a metal or a metal compound selected from metallic iron, iron compounds, metallic copper and copper compounds. -To provide metal compound composite particles.

The present invention also provides a method for uniformly dispersing spherical polymer particles serving as a core in an aqueous solution of a hydrolyzable iron or copper salt, and coating the spherical polymer particles with a uniform iron or copper compound on the spherical polymer particles by a hydrolysis reaction. Layer, and optionally oxidation and / or
Another object of the present invention is to provide a method for producing composite particles, characterized in that spherical polymer-metallic iron, iron compound, metallic copper or copper compound composite particles having a desired composition are obtained by performing a reduction treatment.

[0010] The present invention further provides a hollow particle comprising a metal or a metal compound selected from iron metal, copper metal, an iron compound and a copper compound, wherein the hollow particle has internal pores.

[0011] The present invention further provides the above composite particles,
For example, in the presence of oxygen or hydrogen or in a vacuum 100
A method for producing the hollow particles, wherein the core polymer is decomposed by heating the particles to a temperature of not less than ℃, pores are provided inside the particles, and oxidation and / or reduction treatment is performed as necessary. is there.

[Spherical polymer-metal compound composite particles] The spherical polymer-metal compound composite particles will be described in detail. The spherical polymer particles of the core are not particularly limited, but when the composite particles have particularly excellent durability, abrasion resistance, heat resistance and the like, those having a weight average molecular weight of 5,000 or more are preferable, and More than 10,000 are more preferred. In some cases, a crosslinking monomer may be used during the polymerization of the spherical polymer particles of the core to effect crosslinking. Regarding the glass transition point (Tg), the Tg of the copolymer serving as the core in terms of heat resistance, abrasion resistance and the like is usually 80 ° C. or higher, preferably 90 ° C. or higher.

The composition of the polymer serving as the core is not limited at all. However, when the composite particles are expected to have durability and heat resistance, a styrene (co) polymer, a methyl methacrylate (co) polymer, a divinylbenzene ( (Co) polymer and / or
Alternatively, a polymer mainly composed of a vinylidene chloride (co) polymer is preferable. Among these, a styrene (co) polymer and a methyl methacrylate (co) polymer are more preferable. Examples of the crosslinkable monomers described above include, for example, divinylbenzene, ethylene glycol dimethacrylate,
Examples thereof include trimethylolpropane trimethacrylate, and among them, divinylbenzene is particularly preferable because of excellent abrasion resistance and strength.

On the other hand, various properties can be imparted to the composite particles by changing the composition of the shell. For example,
When the composite particles are to be magnetized, the shell composition is preferably magnetite (Fe ₃ O ₄ ), maghemite (γ-Fe ₂ O ₃ ), and particularly preferably magnetite. Such composite particles can be used for various applications as magnetic particles.

When it is intended to impart optical properties, electrical properties, biocompatibility, etc. to the composite particles, the composite particles are selected from metallic iron, iron compounds, metallic copper and copper compounds according to the required properties. A shell may be provided.

[Method for Producing Spherical Polymer-Metal Compound Composite Particles] The method for producing the above-described spherical polymer-metal compound composite particles will be described. The method for producing the composite particles,
The surface of the spherical polymer particles as a core is uniformly coated with a metal compound by hydrolyzing a hydrolyzable iron or copper salt by heating or the like, and is subjected to a surface treatment if necessary.

The hydrolysis reaction is preferably carried out at 40 ° C. or higher,
It easily occurs by heating at a temperature of preferably 50 ° C. or more, particularly preferably 60 ° C. or more.

What is important in the above method is to uniformly disperse the spherical polymer particles as the core in the aqueous solution. For example, if the dispersion state is poor and the spherical polymer particles serving as the core particles aggregate and form a cluster of several to several hundreds, the metal compound is coated thereon, and uniform composite particles cannot be formed. Further, the generated composite particles may associate and aggregate in the solution, and may not be redispersed. In order to improve these disadvantages, it is preferable to add a water-soluble polymer and / or a surfactant to the aqueous solution as a dispersibility improver. The use amount of these dispersibility improvers is preferably 1% by weight or more, more preferably 3 to 300% by weight, particularly preferably 5 to 250% by weight, based on the spherical polymer particles serving as the core. Preferred as the water-soluble polymer or surfactant are polyvinylpyrrolidone, polyvinyl alcohol, sodium polycarboxylate, sodium hexametaphosphate, sodium naphthalenesulfonate, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate and the like. More preferred are polyvinylpyrrolidone and sodium dodecyl sulfate. These may be used alone or in combination.

The principle of the formation of the spherical polymer-metal compound composite particles is basically of two types, one of which is that the hydrolyzed metal ion or the complex formed by the hydrolysis is adsorbed on the core spherical polymer particles. The mechanism is to form a coating layer. The other is a mechanism in which very small metal compound fine particles are formed at the initial stage, and are adsorbed to the core spherical polymer particles by heteroaggregation, and the metal compound layer grows on the surface of those particles. It is. In this latter mechanism, the thickness of the coating layer is controlled by the number and particle size of the metal compound particles adsorbed on the spherical polymer particles as the core.

In order to cause the above-mentioned hetero-aggregation, it is not always necessary to impart a charge to the core spherical polymer, but it is preferable to impart a plus or minus charge.
For example, when the hydrolysis reaction of the metal salt occurs at a pH equal to or higher than the isoelectric point of the metal compound fine particles, if the spherical polymer having a positive charge is used as the core, the adsorption is performed efficiently. Also,
When the hydrolysis reaction of the metal salt occurs at a pH below the isoelectric point of the metal compound fine particles, the adsorption is efficient if a spherical polymer having a negative charge is used as the core.

Next, the method for producing the composite particles will be described separately for the case of iron-based composite particles and the case of copper-based composite particles. First, a method for producing iron-based composite particles will be described. In this method, a hydrolyzable iron salt is hydrolyzed, and is reacted in an aqueous solution to produce composite particles. The above method is very cheap, efficient and safe from an industrial point of view. Here, the hydrolyzable iron salt is, for example, Fe (N
O ₃ ) ₃ , FeCl ₃ , Fe (SO ₄ ) _{3 and the} like. The amount of the hydrolyzable iron salt used is preferably 0.01 mmol / l liter or more of the reaction mixture, more preferably 0.1 mmol / l liter of the reaction mixture, particularly preferably 1 mmol / l.
The reaction mixture is 1 liter, but the upper limit is generally 100 mmol / l of the reaction mixture.

These are easily hydrolyzed by heating.
As a result, iron oxides are formed, and these are uniformly coated on the surface of the spherical polymer particles serving as the core. In order to improve the coating efficiency, the charge difference between the iron oxide particles and the spherical polymer particles during nucleation may be increased. For example, if the spherical polymer is an anionic one, the initial pH of the reaction mixture is lowered to a region where the zeta potential of the iron oxide particles shows a positive maximum, the charge difference is maximized, and the hydrolysis reaction is performed in that state. It is possible to efficiently and uniformly produce composite particles coated. Acids used to lower the pH include hydrochloric acid,
Lewis acids and organic acids such as sulfuric acid, nitric acid, oxalic acid and acetic acid. The reaction is hardly affected by the type of these acids, but is preferably hydrochloric acid, sulfuric acid and nitric acid.

The concentration of these acids is, for example, when the concentration of the hydrolyzable iron salt is 5 mmol / l of the reaction mixture, preferably 0.001 to 1 mol / l of the reaction mixture, more preferably 0.1 to 1 mol. 001 to 0.5 mol / l of reaction mixture,
Particularly preferably, 0.005 to 0.2 mol / reaction mixture 1
l. To increase the iron oxide concentration in the shell,
This can be achieved by adding urea to the reaction system to increase the hydrolysis rate with heating, to cause the hetero-aggregated hematite fine particles to be aggregated densely with a smaller particle size, and then to grow the shell layer. The amount of urea used is, for example, when the iron salt concentration is 5 mmol / l of the reaction mixture, preferably 0.1 to 5000 mmol / l of the reaction mixture, more preferably 0.1 to 2000 mmol / l of the reaction mixture,
Particularly preferably, 0.1 to 500 mmol / reaction mixture 1
l.

The density of iron oxide in the shell can also be increased by adding an alcohol to the reaction system to greatly reduce the hydrolysis rate and growing the shell layer slowly. The type of alcohol used herein is not particularly limited, but is preferably methanol, ethanol, 1-propanol, 2-propanol, n-butanol, sec-butanol, t-butanol, or the like. Of these, methanol, ethanol, 2-propanol and the like are particularly preferred. The amount used is 0 to water
It is preferably 95% by volume, more preferably 10 to 70% by volume, particularly preferably 30 to 50% by volume.

To increase the thickness of the iron oxide coating on the shell,
The hydrolysis may be caused by increasing the iron salt concentration. Alternatively, the coating layer can be thickened by further performing a hydrolysis reaction of an aqueous solution of iron salt using the spherical polymer-iron oxide composite particles having a thin coating layer as seeds.

The iron oxide of the shell includes, for example, hematite, magnetite, maghemite, FeO and the like. If necessary, a surface treatment can be performed to convert between hematite, magnetite and maghemite. For example, if the shell is hematite, preferably 15
Magnetite can be obtained by hydrogen reduction at 0 ° C. or higher, more preferably 250 ° C. or higher. When the shell is magnetite, maghemite can be formed by oxidizing in air at preferably 150 ° C. or higher, more preferably 200 ° C. or higher. When the shell is maghemite, magnetite can be formed by heating to preferably 150 ° C. or higher, more preferably 200 ° C. or higher.

Next, a method for producing the copper-based composite particles will be described.
Here, too, the hydrolyzable copper salt is hydrolyzed in the presence of carbonate ions. The reaction is carried out in an aqueous solution to cover the spherical polymer surface as basic copper carbonate to form composite particles. Hydrolyzable copper salts include, for example, Cu (NO ₃ ) ₂ , CuCl ₂ ,
CuSO _{4 and the} like. Particularly preferred is Cu (N
O ₃ ) ₂ . The amount of these hydrolyzable copper salts used is
It is preferably at least 0.01 mmol / l of the reaction mixture, more preferably 0.1 mmol / l of the reaction mixture, particularly preferably 1 mmol / l of the reaction mixture.
If it is 0 mmol / l liter of the reaction mixture, it is difficult to produce composite particles.

These are easily hydrolyzed at room temperature or by heating in the presence of carbonate ions to uniformly coat the surface of the spherical polymer particles as basic copper carbonate. Examples of the supply source of carbonate ions include carbon dioxide, urea, carbonic acid, and carbonate, and among them, urea and carbonic acid are particularly preferable. When urea is used, the pH at the end of the reaction is controlled to preferably 7 or less, more preferably 6.5 or less, particularly preferably 6 or less, in order to form the coating layer as basic copper carbonate. If it becomes higher, it becomes copper oxide. The amount of urea used is preferably 1000 times or less the copper salt concentration, more preferably 800 times or less, particularly preferably 500 times or less. When the amount of urea used is 1/100 or less of the copper salt concentration, the compound may not be formed. When carbonic acid is used, the amount of carbonic acid used is preferably 1000 times or less the copper salt concentration, more preferably 1 time.
It is at most 00 times, particularly preferably at most 10 times. In addition,
If the amount of carbonic acid used is 1/1000 or less of the copper salt concentration, the compound may not be formed.

The basic copper carbonate of the shell is converted to copper oxide by treating it with an alkali at room temperature or by heating it in air at preferably 200 ° C. or more, more preferably 240 ° C. or more, and particularly preferably 250 ° C. or more. be able to.
When the shell is made of copper oxide, it can be converted to metallic copper by heating it in a hydrogen atmosphere to preferably 100 ° C. or more, more preferably 130 ° C. or more, and particularly preferably 140 ° C. or more. This means that even if the shell is basic copper carbonate, it can be reduced to metallic copper as well. The particle diameters of the spherical polymer-metal compound composite particles and the spherical polymer-metal copper composite particles obtained as described above are preferably 0.07 to 50 in production.
μm, more preferably 0.2 to 20 μm, particularly preferably 0.4 to 10 μm, and the ratio of the particle diameter of the spherical polymer particles serving as the core to the particle diameter of the composite particles is preferably 0.4 to 0.95. And more preferably 0.5 to
0.9, particularly preferably 0.6 to 0.9.

[Method of Producing Hollow Particles] The method comprises heating the spherical polymer-metal compound composite particles to at least 100 ° C. or higher, preferably 450 ° C. or higher, in the presence of oxygen or hydrogen to obtain a spherical core. Polymer particles are decomposed, gasified and scattered from inside the particles, pores are provided inside the particles, and oxidization and / or reduction treatment is performed as necessary to obtain hollow particles having various compositions.

As a result, hollow particles having a monodispersed and uniform shell layer can be obtained, and the particle diameter and the pore diameter can be freely controlled.

In the above method for producing hollow particles, the polymer of the core is not limited at all, but it is preferable that the polymer is not crosslinked in order to completely decompose and easily gasify. Thereby, vacancies can be developed in a short time at a low temperature. For example, if the core polymer is crosslinked, 80
It is necessary to heat at 0 ° C. or higher, more preferably at 1100 ° C. or higher. Accordingly, the monomer component of the core polymer is preferably a monomer component such as styrene, acrylonitrile, or vinyl acetate as the main component in that it is completely decomposed by heating. When the heating temperature is 1200 ° C. or higher, cracks are easily formed on the surface of the hollow particles, and
If the rate of temperature rise and the rate of cooling are also rapid, the shell tends to collapse. Therefore, the rate of temperature rise is 30 ° C./min or less,
The cooling rate is preferably 20 ° C./min or less.

The spherical hollow particles obtained as described above can be interconverted into hollow particles made of iron oxide such as hematite, magnetite, maghemite, metallic iron or metallic copper by subjecting them to oxidation and / or reduction treatment as required.
For example, in the case of hollow hematite particles, hydrogen reduction is performed at 150 ° C. or higher, more preferably 250 ° C. or higher, to obtain hollow magnetite particles. The hollow magnetite particles are converted to hollow maghemite particles by careful oxidation at room temperature or by heating. The hollow maghemite particles become hollow hematite particles when heated to 150 ° C. or higher, more preferably 300 ° C. or higher.

The hollow iron oxide particles can be obtained by reducing the hollow iron oxide particles in a hydrogen atmosphere, preferably at a temperature of 500 ° C. or higher, more preferably 550 ° C. or higher.

The hollow copper oxide particles can be obtained by heating in a hydrogen atmosphere to preferably 100 ° C. or higher, more preferably 130 ° C. or higher, particularly preferably 140 ° C. or higher.

The particle diameter of the hollow particles is usually 0.04 to
50 μm, preferably 0.04 to 40 μm, more preferably 0.1 to 10 μm, particularly preferably 0.2 to 1 μm
m. The ratio of the inner diameter to the particle diameter is usually 0.1.
It is 3 to 0.95, preferably 0.5 to 0.9, particularly preferably 0.6 to 0.9, and if it is out of this range, it may be difficult to produce.

[0037]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[Spherical Polymer Particles as Core] Example-1 574 g of distilled water, 1.0 g of potassium persulfate and 0.30 g of sodium dodecyl sulfate were placed in a 1000 ml four-necked flask for polymerization, and stirred for 10 minutes. Completely dissolved.

Then, 100 g of styrene was added and N _{2 was} added.
Stir for 5 minutes while purging the gas. Thereafter, the flask was placed in a water bath and reacted at 80 ° C. for 4 hours, and then cooled to room temperature. After cooling, aggregates were removed using filter paper. The total solid content of the obtained spherical polymer particle dispersion liquid composed of a styrene polymer was 14.7% by weight. The average particle diameter of the spherical polymer particles was 0.42 μm. The glass transition point (Tg) of the spherical polymer particles was 100 ° C., and the weight average molecular weight was 10,000. Distilled water was added to adjust the concentration of the spherical polymer particle dispersion to 1 g / l.

Example 2 In a 1000 ml four-necked flask for polymerization, 576 g of distilled water and T
0.5 g of riton X-100 (manufactured by Rohm and Haas, nonionic surfactant) and 1.0 g of 2,2'-azobis (2-methylpropionitrile) (manufactured by AIBN. Aldrich) are added for 10 minutes. Stir and completely T
riton X-100 and AIBN were dissolved. Next, 100 g of styrene was added, and the mixture was stirred for 5 minutes while purging with N ₂ gas. Thereafter, the flask was placed in a water bath and reacted at 70 ° C. for 12 hours, and then cooled to room temperature. After cooling, aggregates were removed using filter paper. The total solid content of the obtained spherical polymer particle dispersion liquid composed of styrene polymer particles was 14.2% by weight. The average particle size of the spherical polymer was 0.17 μm. The glass transition point (Tg) of the spherical polymer was 101 ° C.
The weight average molecular weight was 95,000. Distilled water was added to adjust the concentration of the spherical polymer particle dispersion to 1 g / l.

Example 3 70 g of the spherical polymer particle dispersion obtained in Example 2, 929 g of distilled water and 1.0 g of sodium persulfate were placed in a 1000 ml four-necked flask for polymerization, and stirred for 10 minutes. Dissolved. Next, 90 g of styrene and 10 g of divinylbenzene were added, and the mixture was stirred for 5 minutes while purging with N ₂ gas. Thereafter, the flask was placed in a water bath, reacted at 70 ° C. for 12 hours, and then cooled to room temperature. After cooling, aggregates were removed using filter paper. The resulting styrene / divinylbenzene copolymer spherical polymer particle dispersion had a total solid content of 9.6% by weight, and the average particle size of the spherical polymer particles was 0.35 μm. The spherical polymer particles had no glass transition point (Tg) at 150 ° C. or lower, and had a weight average molecular weight of 1,000,000 or more. Distilled water was added to adjust the concentration of the spherical polymer particle dispersion to 1 g / l.

Example-4 STADEX SC-310 manufactured by Nippon Synthetic Rubber Co., Ltd.
-S (spherical styrene polymer particles) was used. The average particle size was 3.1 μm. Distilled water was added to adjust the concentration of the spherical polymer particle dispersion to 1 g / l.
The spherical polymer particles have a glass transition point of 105.
℃, the weight average molecular weight was 700,000.

Example-5 Duke Scientific Corporation
on, No. 120 particles (spherical styrene / divinylbenzene copolymer particles) were used. Average particle size is 20
μm, the glass transition point was 150 ° C. or more, and the weight average molecular weight was 1,000,000 or more. Distilled water was added to adjust the concentration of the spherical polymer particle dispersion to 1 g / l.

[Production of Composite Particles] Example 1 1 ml of the spherical polymer particle dispersion (concentration 1 g / l) obtained in Production Example 1 of spherical polymer particles, and 3 of polyvinylpyrrolidone (weight average molecular weight 360,000) 3% by weight aqueous solution;
1 ml of urea aqueous solution adjusted to 4 mol / l, 0.1 ml / l
3 ml of hydrochloric acid, 1 ml of distilled water and 5 × 10 of iron (III) chloride
^{A −2} ml / l aqueous solution was placed in a pressure-resistant test tube with a stopper. After thoroughly stirring the reaction mixture for 1 minute in an ultrasonic water bath, the mixture was placed in a thermostat set at 100 ° C. in advance for 2 days.
It was hydrolyzed. Thereafter, the mixture is cooled to room temperature, the composite particles are sedimented by centrifugation, the supernatant solution is separated, distilled water is added, and the particles are completely dispersed in an ultrasonic water bath. Was repeated 5 times. Thereafter, the obtained composite particles were dried at room temperature.

When the obtained composite particles were observed with an electron microscope, the average particle diameter was 0.58 μm, and the ratio of the core particle diameter to the particle outer diameter was 0.72, and the particle surface was completely covered with a uniform layer. Spherical composite particles. When the composite particles were analyzed, it was confirmed that the core was composed of a polystyrene polymer and the shell was composed of α-Fe ₂ O ₃ . An electron micrograph of the composite particles is shown in FIG.

The following components were used in the above production. 0.1 g of the styrene copolymer of Example-1 / 1 l of the reaction mixture solution 5.0 × 10 ⁻³ mol of iron (III) chloride / 1 l of the reaction mixture solution 0.9% by weight of polyvinylpyrrolidone (Mw 360,000) 0.04 mol of urea / Reaction mixture 1L Hydrochloric acid 0.03mol / Reaction mixture 1L

Examples 2 to 21 The method was basically the same as that of Example 1, except that the components used for hydrolysis and the production conditions were changed as shown in Tables 1 to 6. To 21. The shapes, compositions, and the like of the resulting composite particles are shown in Tables 1 to 6 together with Example 1.

[0048]

[Table 1]

Note: PVP = polyvinylpyrrolidone ST = styrene DVB = divinylbenzene PST = styrene polymer P (ST / DVB) = styrene / divinylbenzene copolymer

[0050]

[Table 2]

[0051]

[Table 3]

[0052]

[Table 4]

[0053]

[Table 5]

[0054]

[Table 6]

Example 22 0.5 g of composite particles having a core of styrene / divinylbenzene copolymer and a shell of hematite obtained in Example 9 were subjected to 10 ° C./min from room temperature to 200 ° C. in a hydrogen gas atmosphere. The temperature was raised and held at 200 ° C. for 3 hours. Then 2
It was cooled to room temperature at a rate of 0 ° C./min. The average particle diameter of the obtained composite particles was 0.43 nm. The ratio of the particle diameter of the core particles to the outer diameter of the particles was 0.83. When the composite particles were analyzed, the core was a styrene / divinylbenzene copolymer,
The shell was magnetite.

Examples 23 to 27 The method was basically the same as that of Example 22, except that the composite particles used and the firing conditions were changed as shown in Tables 7 and 8. did. The shapes, compositions, and the like of the resulting composite particles are shown in Tables 7 and 8 together with Example 22.

[0057]

[Table 7]

[0058]

[Table 8]

Example 28 The core obtained in Example 1 was a styrene polymer, and the shell was α.
0.3 g of -Fe ₂ O ₃ composite particles were heated from room temperature to 800 ° C. at a rate of 10 ° C./min in an air atmosphere and held at 800 ° C. for 3 hours. Thereafter, the mixture was cooled to room temperature at a rate of 20 ° C./min. The average particle diameter of the obtained spherical hollow particles is 0.1.
The ratio of the internal voids to the particle outer diameter was 54 nm, and the ratio was 0.78. When the hollow particles were analyzed, the core was voids and the shell was α-Fe ₂ O ₃ .

Examples 29 to 35 The method was basically the same as that of Example 28, except that the composite particles used and the production conditions were changed as shown in Tables 9 to 10. did. The shapes, compositions, and the like of the resulting hollow particles are shown in Tables 9 to 10 together with Example 28.

[0061]

[Table 9]

[0062]

[Table 10]

Example 36 0.3 g of the hollow hematite particles obtained in Example 28 was heated from room temperature to 350 ° C. at a rate of 10 ° C./min in a hydrogen gas atmosphere, and held at 350 ° C. for 1 hour. Then 2
It was cooled to room temperature at a rate of 0 ° C./min. The average particle diameter of the obtained hollow particles was 0.50 μm, and the ratio of internal pores to the particle diameter was 0.84. When the hollow particles were analyzed, the core was void and the shell was magnetite.

Examples 37 to 41 The procedure was basically the same as in Example 36, except that the hollow particles used and the production conditions were changed as shown in Tables 11 to 12. did. The shapes, compositions, and the like of the resulting hollow particles are shown in Tables 11 to 12 together with Example 36.

[0065]

[Table 11]

[0066]

[Table 12]

[0067]

Industrial Applicability The present invention relates to the modification of spherical particles widely used in various applications, and has high strength, high heat resistance, can exhibit high functions, and can be used as a pharmaceutical or diagnostic agent. , Electronic materials, conductive materials, heat-resistant materials, lubricants, catalysts, magnetic materials,
It can be widely applied to applications such as optical materials. In the case of hollow particles having magnetism, many applications can be expected not only for magnetic microcapsules but also for other magnetic materials.

[Brief description of the drawings]

FIG. 1 is an electron micrograph showing the structure of a spherical styrene polymer (core) / α-Fe ₂ O ₃ composite particle obtained in Example 1. The scale in the figure indicates 0.4 μm.

FIG. 2 is an electron micrograph showing the structure of a spherical styrene polymer (core) / Cu (OH) ₂ CuCO ₃ composite particle obtained in Example 15. The scale in the figure indicates 0.4 μm.

Claims (3)

[Claims] 1. At least one metal fine particle selected from (1) metal iron and metal copper or (2) at least one metal selected from iron oxide, basic copper carbonate and copper oxide on the surface of the spherical polymer particles. Spherical polymer particles-metal compound composite particles having a shape in which the metal compound fine particles are adsorbed by aggregation. 2. The spherical polymer particles according to claim 1, wherein the metal compound fine particles are a hydrolyzable iron salt or a hydrolyzable copper salt hydrolyzate, an oxide thereof or a reduced product thereof. Metal compound composite particles. 3. Spherical hollow particles having a particle diameter of 0.04 to 50 μm, comprising a metal compound selected from metallic iron, iron oxide, metallic copper, basic copper carbonate and copper oxide, and having internal pores. .