JP4540314B2 - Method for producing metal-containing resin particles - Google Patents

Description

The present invention relates to a method for producing metal-containing resin particles.

  Metal-containing resin particles in which metal or metal oxide is incorporated into resin particles with excellent monodispersibility are antibacterial, antifungal, deodorant, flame retardant, ultraviolet protection, heat storage, surface property improvement, conductivity , Anticorrosive, lubricity, magnetism, fluorescence, light reflectivity, light selective absorption, heat absorption, heat conduction, heat reflection, etc., particles for color copying, paints, adhesives, circuits Application to applications such as anisotropic conductive films for connection, electromagnetic shields, medical diagnostic agents, simple substances, and column fillers for analyzers is expected.

  Conventional methods for obtaining metal-containing resin particles are as follows: 1) After producing resin particles, a metal or metal oxide film is formed on the surface by plating, coating, interfacial aggregation, interfacial precipitation, or the like. 2) A method of coating the surface of fine particles made of metal or metal oxide with a resin by interfacial polymerization or the like 3) Suspending or emulsifying fine particles made of metal or metal oxide and a polymerizable monomer in a solvent, followed by polymerization, Method of containing fine particles made of metal or metal oxide inside resin particles 4) Combining separately produced resin particles and fine particles made of metal or metal oxide using a physical method such as a hybridizer There are methods.

  As the method 1), for example, JP-A-5-138809 (Patent Document 1) discloses a method of ferritizing the surface of resin particles by precipitating an iron compound in the resin particle emulsion. ing. However, since the metal-containing resin particles obtained have metal oxides attached to the resin particle surfaces, the surface smoothness cannot be maintained, and the bonding force between the resin particle surfaces and the metal oxides is weak. There was a problem that the metal oxide peeled off from the surface of the resin particles when kneaded with the material or when pressurized. Furthermore, particularly in applications such as medical diagnostics, when trying to immobilize proteins or the like on metal-containing resin particles, the particle surface is a metal or metal oxide, so the selection of functional group species that adsorb proteins is limited. However, there is a problem that it is difficult to specifically adsorb the necessary protein species.

  As the method 2), for example, JP-A-2-300205 (Patent Document 2) discloses a method of coating the surface of particles made of metal or metal oxide with a resin by graft polymerization. However, since the particle size of the obtained metal-containing resin particles depends on the particle size of particles made of metal or metal oxide, which is extremely difficult to control the particle size, the particle size distribution of the obtained metal-containing resin particles becomes wide. In recent years, there has been a problem that it is difficult to cope with finer and higher sensitivity.

  As the method of 3) above, for example, JP-A-59-221302 (Patent Document 3) disperses a lipophilic-treated metal or metal oxide in a polymerizable monomer and suspends it. A method for turbid polymerization is disclosed. However, in this case as well, there is a problem that the particle size distribution of the obtained metal-containing resin particles is wide, and further, there is a large variation in the content of metal or metal oxide per particle.

  Further, the method 4) has a problem that the resin particles are aggregated, and thus metal-containing resin particles having a small particle diameter cannot be obtained.

JP-A-5-138209 JP-A-2-300205 JP 59-221302 A

  Furthermore, the conventional metal-containing resin particles have a problem that the metal-containing resin particles are easily aggregated and formed into an aggregate even after the production, and the dispersion stability is insufficient.

  The present invention provides metal-containing resin particles in which the metal or metal oxide does not fall off from the resin particles, the particle size and the like can be made uniform, and the surface smoothness and dispersion stability are excellent. The purpose is to do.

  In the metal-containing resin particles of the present invention, an aggregate layer of fine particles composed of metal and / or metal oxide is formed on the surface of the core particle, and further, a polymerizable monomer having an anionic group and another polymerizable monomer A resin layer made of a copolymer and / or a polymer of a polymerizable monomer having an anionic group is formed.

The present invention is described in detail below.
The core particle used in the present invention is the core of the metal-containing resin particle of the present invention, and is preferably a resin particle made of a resin obtained by polymerizing or copolymerizing a polymerizable monomer, but is not limited thereto. Instead, for example, it may be made of an organic compound.

Specific examples of the resin constituting the resin particles include polyolefins such as polyethylene, polydienes such as polybutadiene, polynorbornene, polyethers such as polyethylene glycol and polypropylene glycol, polystyrene, poly (meth) acrylic acid, poly Fluorine resins such as (meth) acrylic acid ester, polyvinyl alcohol, polyvinyl ester, polyamide, polyimide, (un) saturated polyester, polyurethane, polytetrafluoroethylene, acrylonitrile / styrene copolymer resin, styrene / butadiene copolymer resin, ABS resin , Vinyl resin, polycarbonate, polyacetal, polyethersulfone, polyphenylene oxide, benzoguanamine resin, phenol resin, melamine resin, diallyl phthalate Allyl resins such as preparative resin, furan resin, epoxy resin, silicone resin, sugars, starches, cellulose, polypeptides and the like, among them polystyrene and poly (meth) acrylic acid esters preferred.
The (meth) acrylic means acrylic or methacrylic.

  The resin particles may be obtained as resin particles in advance to obtain the metal-containing resin particles of the present invention. As described later, the polymerizable monomer is polymerized or co-polymerized in the same system for obtaining the metal-containing resin particles. It is preferable to polymerize into resin particles.

In the case where a polymerizable monomer is polymerized or copolymerized into a resin particle in a system for obtaining metal-containing resin particles, the polymerizable monomer is not particularly limited as long as it can form particles by polymerization or copolymerization. The radically polymerizable monomer is preferable, and any conventionally known monomer can be used as the radically polymerizable monomer.
In addition, examples of the polymerizable monomer include those having an anionic group and those having no anionic group, but a polymerizable monomer having no anionic group is used at the stage of preparing the resin particles. Is preferred. Further, even when a polymerizable monomer having an anionic group and a polymerizable monomer having no anionic group are used in combination, after the polymerization of the polymerizable monomer having no anionic group is started, It is preferred to add a polymerizable monomer having no anionic group to the system.

  Examples of the polymerizable monomer having no anionic group include aromatic vinyl monomers such as styrene, α-methylstyrene, p-methylstyrene, chloromethylstyrene, vinyltoluene, divinylbenzene, and derivatives thereof; ) Methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, benzyl (meth) acrylate, glycidyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, ( (Meth) acrylate monomers or derivatives such as trifluoroethyl acrylate, pentafluoropropyl (meth) acrylate, cyclohexyl (meth) acrylate, ethylene glycol di (meth) acrylate; olefins such as ethylene Monomers or their derivatives Diene monomers such as butadiene or derivatives thereof; norbornene; vinyl monomers such as vinyl chloride and vinylidene fluoride or derivatives thereof; unsaturated nitrile monomers such as acrylonitrile or derivatives thereof; vinyl esters such as vinyl acetate and vinyl propionate; Nonionic functional group-containing vinyl monomers such as methoxypolyethylene glycol methacrylate or salts thereof; vinylbenzylamine, 3-acrylamido-3-methylbutyltrimethylammonium chloride, (meth) acrylamidopropyltrimethylammonium chloride, Examples include cationic vinyl monomers such as dimethylaminoethyl methacrylate tetraoxide salt. Among them, styrene which is an aromatic vinyl monomer Beauty (meth) acrylic ester monomers are preferred.

  Examples of the polymerizable monomer having an anionic group include sulfonic acid group-containing vinyl monomers such as styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, sodium styrenesulfonate, or salts thereof; (meth) acrylic Examples thereof include carboxyl group-containing vinyl monomers such as acids or salts thereof; hydroxyl group-containing vinyl monomers such as hydroxyethyl (meth) acrylate or salts thereof, among which sodium styrenesulfonate is preferable.

The resin particles preferably have a silanol group on the surface of the resin particles because the resin particles have an effect of improving interfacial bonding properties with fine particles made of metal and / or metal oxide, which will be described later.
The method for introducing a silanol group into the resin particle is not particularly limited. For example, a method for obtaining a resin particle by performing polymerization using a polymerizable monomer having a silanol group, a functional group that can be converted into a silanol group. Examples thereof include a method of converting a functional group on the surface to a silanol group after polymerization using a polymerizable monomer having s. A polymerizable monomer having a silanol group and a polymerizable monomer having a functional group that can be converted into a silanol group are used in combination with other polymerizable monomers in accordance with the desired amount of silanol groups, and resin particles are used as a copolymer. It is preferable to configure.

  Examples of the polymerizable monomer having a silanol group include vinyltrimethoxysilane, vinyltriethoxysilane, allyltrichlorosilane, (meth) acryloxytrimethylsilane, (meth) acryloxypropyldimethoxysilane, and (meth) acryloxypropyl. Examples include trimethoxysilane, (meth) acryloxypropylmethyldichlorosilane, (meth) acryloxypropyltris (trimethylsiloxy) silane, N-allylaminopropyltrimethoxysilane, and styrylethyltrimethoxysilane.

  Examples of the polymerizable monomer having a functional group that can be converted to a silanol group include a carboxyl group-containing vinyl monomer such as (meth) acrylic acid; hydroxyethyl (meth) acrylate, polyoxyethylene (meth) acrylate, (meth ) Hydroxyl group-containing vinyl monomers such as hydroxypropyl acrylate; and amino group-containing vinyl monomers such as acrylamide. As a method for converting a functional group that can be converted into a silanol group into a silanol group, specifically, a functional group that can be converted into a silanol group such as a carboxyl group, a hydroxyl group, and an amino group on the particle surface is converted to methyltriol. The method of silanol-ized with ethoxysilane etc. is mentioned.

  The amount of silanol groups on the surface of the resin particles is the amount of all polymerizable monomers constituting the resin particles (polymerizable monomer having a silanol group and polymerizable monomer having a functional group that can be converted into a silanol group + other polymerizable monomers). The amount of the polymerizable monomer having a silanol group and the polymerizable monomer having a functional group that can be converted to a silanol group is preferably 0.1 to 10% by weight. By using in this range, a sufficient amount of silanol groups can be introduced on the surface of the resin particles.

  The organic compound constituting the core particle is not particularly limited. For example, (un) saturated hydrocarbon, aromatic hydrocarbon, (un) saturated fatty acid, aromatic carboxylic acid, (un) saturated ketone, aromatic Examples include ketones, (un) saturated alcohols, aromatic alcohols, (unsaturated) amines, aromatic amines, (unsaturated) thiols, aromatic thiols, organosilicon compounds, and derivatives thereof. The above (unsaturated) means saturated or unsaturated.

The particle diameter of the core particle is not particularly limited and may be appropriately determined according to the use, but is preferably 0.05 to 1000 μm.
The method for measuring the particle size is not particularly limited, and for example, the particle size can be measured by using a particle size distribution analyzer, image analysis of an electron microscope (SEM) photograph, or the like.

  It does not specifically limit as a manufacturing method of the said core particle, A conventionally well-known method can be used. Examples thereof include a mini-emulsion polymerization method, an emulsion polymerization method, a phase inversion emulsion polymerization, a micro suspension polymerization method, a suspension polymerization method, a dispersion polymerization method, a seed polymerization method, and a soap-free precipitation polymerization method. Among these, a soap-free precipitation polymerization method having excellent particle size controllability is preferably used.

When the particle size distribution of the obtained core particles becomes large, the particle size of the obtained metal-containing resin particles becomes non-uniform, the metal content per particle becomes non-uniform, or the metal-containing resin particles become binders, etc. The Cv value is preferably 10% or less because it may be difficult to disperse uniformly.
The Cv value is a value represented by the following formula using an average particle size obtained by each particle size measurement method and a standard deviation value.
Cv (%) = (standard deviation / average particle diameter) × 100

  The agglomerated layer constituting the metal-containing resin particles of the present invention is formed by agglomerating fine particles comprising metal and / or metal oxide on the surface of the core particles. Note that either one of the metal fine particles and the metal oxide fine particles may be used, or both may be used in combination.

The metal and metal oxide are not particularly limited, and examples of the metal include Ti, V, Cr, Fe, Mn, Co, Ni, Cu, Zn, Ga, Ge, Se, Zr, Nb, and Mo. Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, etc., and metal oxides As these, these oxides etc. are mentioned. Moreover, you may use these 2 or more types as an alloy. Of these, metal oxides are preferable.
Moreover, when using the obtained metal containing resin particle as a magnetic particle, it is preferable to use what has magnetism, such as a ferrite, magnetite, and terbium oxide among the said metals and metal oxides.

  The fine particles comprising the metal and / or metal oxide have a strong bond between the core particle and the agglomerated layer and a bond between the agglomerated layer and the resin layer described later in the obtained metal-containing resin particles. It is preferable to use one having a polymerizable unsaturated group on the surface. As said polymerizable unsaturated group, a vinyl group, an alkenyl group, an aryl group etc. are mentioned, for example, Among these, a vinyl group is preferable.

  The method for introducing the polymerizable unsaturated group into the surface of the fine particles composed of a metal and / or metal oxide is not particularly limited. For example, 1) an atomic group having a bondability with a metal such as a coordination bond compound. And a method of bonding a compound having a polymerizable unsaturated group to the surface of the fine particle, 2) after introducing a hydroxyl group to the surface of the fine particle, an atomic group having reactivity with the hydroxyl group, and a polymerizable unsaturated group 3) A method of bonding a compound having a fine particle surface to the surface of a fine particle, 3) introducing a hydroxyl group on the metal surface of the fine particle by mercaptohexanol, etc., then reacting with methacryloyloxyethyl isocyanate, etc., and introducing a polymerizable vinyl group, etc. Examples thereof include a method of introducing a polymerizable unsaturated group into the surface of the fine particles.

The atomic group capable of binding to the metal described in the method 1) is not particularly limited as long as it can form a coordinate bond, ionic bond, covalent bond, or the like with the metal. For example, silane, silanol, carboxyl Group, carbonyl group, hydroxyl group, amino group, ammonium compound, nitro group, cyano group, mercapto group, sulfo group, sulfonium compound, boric acid, oxazoline, pyrrolidone, phosphoric acid and the like. In particular, in the method 1), since the compound is preferably coordinated to a metal, it preferably has an atomic group containing a sulfur atom, a nitrogen atom, a phosphorus atom, or the like that exhibits a coordination bond to the metal.
Specific examples of the compound having an atomic group having a bonding property to a metal and a polymerizable unsaturated group in the above method 1) include, for example, methacryloxypropyltrimethoxysilane, (meth) acrylic acid, allyl Sulfonic acid, p-styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, (meth) acrylic acid phenyldimethylsulfonium methylsulfate, vinylbenzylamine, (meth) acrylic acid dimethylaminoethyl, 2-methacrylic acid Examples include leuoxyethyl acid phosphate.

  Examples of the atomic group having reactivity with the hydroxyl group described in the method 2) include silane, silanol, chlorosilyl and the like, and examples of the compound having these atomic groups include a silane coupling agent. Specifically, for example, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrichlorosilane, (meth) acryloxytrimethylsilane, (meth) acryloxypropyldimethoxysilane, (meth) acryloxypropyltrimethoxysilane, (meth ) Acryloxypropylmethyldichlorosilane, (meth) acryloxypropyltris (trimethylsiloxy) silane, N-allylaminopropyltrimethoxysilane, styrylethyltrimethoxysilane and the like.

The particle size of the fine particles comprising the metal and / or metal oxide may be appropriately determined according to the particle size or use of the metal-containing resin particles obtained, but heteroaggregation on the surface of the core particles is likely to occur. 5 to 1000 nm is preferable.
In addition, in order to improve the smoothness of the surface of the obtained metal-containing resin particles, the particle size of the fine particles comprising metal and / or metal oxide is 5% or less of the particle size of the obtained metal-containing resin particles. Is more preferable, and more preferably 1% or less. If it exceeds 5%, in order to improve the smoothness of the surface of the resulting metal-containing resin particles, the thickness of the resin layer described later must be increased more than necessary, and the metal and / or metal oxide The effect of using the fine particles made of is difficult to be exhibited, and the expected performance cannot be obtained sufficiently.

  The fine particles comprising the metal and / or metal oxide may be a mixture of two or more different particle sizes. In this case, small particles enter the gaps between the large particles, and the density of the aggregated layer is improved. The particle size of any fine particle is preferably in the above range, but the particle size of the small fine particle is preferably ½ or less of the particle size of the large fine particle, and the amount of the small fine particle is 1 by volume relative to the large fine particle. / 4 or less is preferable.

The fine particles comprising the metal and / or metal oxide are produced from the metal and / or metal oxide by any conventionally known method. When the particle size distribution increases, the metal of the metal-containing resin particles obtained is obtained. Since the content becomes non-uniform, the Cv value is preferably 20% or less. In addition, when using together 2 or more types of microparticles | fine-particles with different particle size, it is preferable that Cv value about each particle size is the said range.
The Cv value can be measured with a particle size distribution meter or the like if it is in the state of fine particles before being agglomerated into the core particles, but after forming an agglomerated layer agglomerated on the surface of the core particles, an SEM or TEM photograph It can be measured by image analysis or the like.

  The resin layer constituting the metal-containing resin particles of the present invention covers the above-mentioned aggregated layer, and has a copolymer of an anionic group-containing polymerizable monomer and another polymerizable monomer and / or an anionic group. It consists of a polymer of polymerizable monomers. The resin layer only needs to substantially cover the aggregate layer. For example, the aggregate layer may be partially exposed as long as it does not substantially affect the resin layer.

  Examples of the polymerizable monomer having an anionic group include those similar to those constituting the above resin particles, and among them, the dispersion stability of the obtained metal-containing resin particles is excellent. Is preferred.

  Examples of the polymerizable monomer other than the polymerizable monomer having an anionic group include those similar to the polymerizable monomer having no anionic group constituting the resin particle. Further, as described later, since the polymerization or copolymerization of the resin particles as the core particles and the formation of the resin layer can be performed in the same system, the above-described resin particles are used as the other polymerizable monomer. Are preferably the same.

  In the metal-containing resin particle of the present invention, as shown in FIG. 1, the above-mentioned aggregated layer composed of fine particles 2 made of metal and / or metal oxide is formed on the surface of the above-mentioned core particle 1, and the aggregated layer further comprises the above-mentioned It is covered with the resin layer 3.

  The content of the fine particles comprising the metal and / or metal oxide in the metal-containing resin particles may be determined as appropriate depending on the metal type, use, etc., but if the amount is reduced, the fine particles comprising the metal and / or metal oxide are reduced. If the contained effect is not sufficiently expressed and the amount is increased, the specific gravity of the metal-containing resin particles becomes too large, and the particle size of the obtained metal-containing resin particles tends to be non-uniform. The amount is preferably 0.1 to 200 parts by weight.

Moreover, although the particle size of the said metal containing resin particle may be suitably determined with the use, Preferably, it is 0.05-1000 micrometers.
Further, the metal-containing resin particles can be obtained by, for example, a method described later. However, the particle size distribution is not uniform when the particle size is increased, and the difference in metal content per particle is also increased. It is preferable that it is 10% or less.

Although it does not specifically limit as a manufacturing method of the said metal containing resin particle, The following method is preferable.
1) The above core particles produced in a separate system are dispersed in a solvent to form a solution, and fine particles composed of the above metal and / or metal oxide are added to the solution to aggregate the fine particles on the surface of the core particles. A method of forming a resin layer by forming an aggregated layer and further polymerizing by adding a polymerizable monomer having an anionic group constituting the resin layer;
2) A polymerizable monomer constituting the core particle, preferably a polymerizable monomer having no anionic group, more preferably styrene or (meth) acrylic acid ester is dispersed in a solvent to form a solution. In which a polymerization initiator or the like is added to initiate polymerization to produce resin particles that are core particles, and during the polymerization reaction, fine particles comprising the metal and / or metal oxide are added to form a resin that is a core particle A method of forming a resin layer by agglomerating fine particles on the surface of the particle to form an aggregated layer, and further polymerizing by adding a polymerizable monomer having an anionic group constituting the resin layer, preferably sodium styrenesulfonate ,
3) A polymerizable monomer having no anionic group and a polymerizable monomer having an anionic group as a polymerizable monomer constituting the core particle in the solvent, preferably styrene or (meth) acrylic acid ester and sodium styrenesulfonate In this solution system, a polymerization initiator or the like is added to initiate polymerization to produce resin particles that become core particles. During the polymerization reaction, the above metal and / or metal oxide is produced. A method of forming a resin layer with the same polymerizable monomer as the core particles by adding the fine particles comprising the above, aggregating the fine particles on the surface of the resin particles as the core particles to form an aggregate layer, and further polymerizing Etc.

In the above method 3), when preparing the solution, after previously dispersing a polymerizable monomer having no anionic group in a solvent and adding a polymerization initiator or the like to initiate polymerization, It is preferable to disperse a polymerizable monomer having an anionic group.
Further, in the above methods 1) to 3), the total amount of the polymerizable monomer having an anionic group added to the solution is decreased, and the dispersion stability of the obtained metal-containing resin particles is decreased, and the total amount is increased. Since small particles are generated in the metal-containing resin particles, it is preferably 0.5 to 2 mol / m ³ in the solution.

  Moreover, as a method of aggregating fine particles made of metal and / or metal oxide on the core particle surface, for example, heteroaggregation is preferable. The heteroaggregation refers to aggregating at least two kinds of fine particles having different properties by van der Waals force or electrostatic interaction.

As the solvent, a conventionally known solvent used for precipitation polymerization can be used, and examples thereof include water-based, alcohol-based, cell solve-based, ketone-based, hydrocarbon-based, and other organic solvents, and these are mixed mixtures. It may be a solvent. Among these, an aqueous solvent and an alcohol solvent are preferable, and an aqueous solvent is more preferable. In addition, it is preferable to use a monomer that dissolves the polymerizable monomer but does not dissolve the produced polymer or copolymer.
Examples of the alcohol solvent include methanol, ethanol, and propanol. Examples of the cellsolv solvent include methyl cellosolve and ethyl cellosolve. Examples of the ketone solvent include acetone and methyl ethyl ketone. , Methyl butyl ketone, 2-butanone, and the like. Examples of the hydrocarbon solvent include toluene and xylene. Examples of the other organic solvent include acetonitrile, N, N-dimethylformamide, Examples thereof include dimethyl sulfoxide and ethyl acetate.

  Furthermore, the solvent is preferably a buffer solution among the aqueous solvents in order to efficiently heteroaggregate fine particles made of metal or metal oxide on the surface of the core particles.

The buffer solution is not particularly limited, and a conventionally known buffer solution can be used depending on the pH to be used. Examples of the buffer solution include hydrochloric acid-potassium hydrogen phthalate (pH 2.2-3.8), citric acid-disodium hydrogen phosphate (pH 2.2-8.0), hydrochloric acid- (sodium barbital + sodium acetate). (PH 2.6-9.2), succinic acid-sodium tetraborate (pH 3.0-5.8), acetic acid-sodium acetate (pH 3.4-5.9), sodium dihydrogen citrate-sodium hydroxide (PH 3.8 to 6.0), potassium dihydrogen citrate-sodium tetraborate (pH 3.8 to 6.0), potassium hydrogen phthalate-sodium hydroxide (pH 4.0 to 6.2), citric acid Potassium dihydrogen-sodium hydroxide (pH 5.0-6.7), maleic acid- (Tris + sodium hydroxide) (pH 5.1-8.5), potassium dihydrogen phosphate-sodium dihydrogen phosphate pH 5.3-8.0), potassium dihydrogen phosphate-sodium tetraborate (pH 5.8-9.2), potassium dihydrogen phosphate-sodium hydroxide (pH 5.8-8.0), hydrochloric acid- Collidine (pH 6.5-8.4), hydrochloric acid-barbital sodium (pH 6.8-9.6), hydrochloric acid-Tris (pH 7.2-9.1), hydrochloric acid-sodium tetraborate (7.5-9) .2), boric acid-sodium carbonate (pH 7.4 to 11.0), boric acid-sodium tetraborate (pH 6.8 to 9.1), hydrochloric acid-aminomethylpropanediol (pH 7.8 to 9.7) ), Phosphoric acid-acetic acid-boric acid-sodium hydroxide (pH 1.8-12), citric acid-sodium dihydrogen phosphate-boric acid-hydrochloric acid-sodium hydroxide-sodium barbital (pH 2.4-pH 12), etc. Can be mentioned. The buffer solution may be used in combination so that it can be used in a wide pH range, or a plurality of buffer solutions having the same pH range may be mixed and used.
The buffer solution to be used can be appropriately selected depending on the desired polymerization system, and is preferably determined in consideration of, for example, the dissociation constant of the polymerization initiator described later and the equipotential point.

  The polymerization initiator is not particularly limited, and any conventionally known radical polymerization initiator can be used. For example, azo compounds, organic peroxides, inorganic peroxides and the like are preferable. Among these, those having a property of being dissolved in an aqueous solvent or an alcohol solvent which are preferable solvents are more preferably used. For example, 2,2′-azobis {2-methyl-N- [2- (1-hydroxy- Butyl)]-propionamide}, 2,2′-azobis [2- (2-imidazolin-2-yl) propane], 2,2′-azobis (2-amidinopropane), 4,4′-azobis (4 In addition to -cyanopentanoic acid) and salts thereof, potassium persulfate, ammonium persulfate, 2,2′-azobis {2- [N- (2-carboxyethyl) amidinopropane, hydrogen peroxide, and the like can be given.

In the present invention, the polymerization of the polymerizable monomer can be performed according to a usual method.
In the above method 1), for example, in a reaction vessel such as a separable flask equipped with a stirrer, a nitrogen introduction tube, a reflux condenser, etc., fine particles comprising a solvent, core particles, and metal and / or metal oxide. And agglomerating fine particles of metal and / or metal oxide on the surface of the core particle, and then adding a polymerizable monomer and an initiator constituting the resin layer, and inert gas such as nitrogen gas for a certain period of time. After replacing the blowing atmosphere, it is preferable to start the polymerization by raising the temperature and maintain the polymerization reaction system at a constant temperature for a certain time to complete the polymerization. At this time, the polymerization initiator is preferably added in a state dissolved in a solvent. The polymerization temperature can be appropriately selected in consideration of the type and concentration of the polymerizable monomer and polymerization initiator to be used, but the range of 60 to 90 ° C. is usually preferable. Furthermore, although the polymerization time varies depending on the polymerization conditions and the like, the polymerization reaction is usually completed in about 12 to 36 hours.

  In the above method 2), for example, in a reaction vessel such as a separable flask equipped with a stirrer, a nitrogen inlet tube, a reflux condenser, etc., a solvent, a polymerizable monomer constituting a core particle, and a polymerization initiator are added, After the inert gas such as nitrogen gas is blown for a certain period of time to replace the atmosphere, the temperature is raised to initiate the polymerization, and the polymerization reaction system is maintained at a certain temperature for a certain period of time to complete the polymerization. At this time, the polymerization initiator is preferably added in a state dissolved in a solvent. The polymerization temperature can be appropriately selected in consideration of the type and concentration of the polymerizable monomer and polymerization initiator to be used, but is usually preferably in the range of 60 to 90 ° C. Thereafter, fine particles composed of metal and / or metal oxide are added, the fine particles composed of metal and / or metal oxide are aggregated on the surface of the resin particles that are core particles, and a polymerizable monomer that constitutes the resin layer and It is preferable to start the polymerization by adding a polymerization initiator and raising the temperature again, and maintain the polymerization reaction system at a fixed temperature for a fixed time to complete the polymerization. The polymerization temperature at this time can also be appropriately selected in consideration of the type and concentration of the polymerizable monomer and polymerization initiator to be used. The polymerization time varies depending on the polymerization conditions and the like, but the polymerization reaction is usually completed in about 12 to 36 hours.

  In the above method 3), for example, in a reaction vessel such as a separable flask equipped with a stirrer, a nitrogen inlet tube, a reflux condenser, etc., a solvent, a polymerizable monomer constituting a core particle, and a polymerization initiator are added, After an inert gas such as nitrogen gas is blown for a certain period of time to replace the atmosphere, polymerization is started by raising the temperature. At this time, the polymerization initiator is preferably added in a state dissolved in a solvent. During the polymerization reaction, metal and / or metal oxide fine particles are added, the fine particles comprising metal and / or metal oxide are agglomerated on the surface of the resin particles that are the core particles generated by the polymerization, and then the polymerization is continued. It is preferable to complete the polymerization by maintaining the polymerization reaction system at a constant temperature for a certain time. The polymerization temperature can be appropriately selected in consideration of the type and concentration of the polymerizable monomer and polymerization initiator to be used, but is usually preferably in the range of 60 to 90 ° C. The polymerization time varies depending on the polymerization conditions and the like, but the polymerization reaction is usually completed in about 12 to 36 hours.

  The obtained metal-containing resin particles can be usually separated from the medium by centrifugation or the like. The separated metal-containing resin particles can be purified by repeatedly washing with alcohol, water or the like. After washing, it can be isolated as a powder by spray drying or reduced pressure drying.

Since the metal-containing resin particle according to claim 1 has an agglomerated layer composed of fine particles 2 made of metal and / or metal oxide on the surface of the core particle 1, as shown in FIG. Functions due to oxides can be expressed.
Moreover, since the outermost surface is the resin layer 3, compared with the conventional particle | grains whose outermost surface shown by FIG. 2 is a metal or a metal oxide, it is excellent in smoothness and functional group selectivity. In addition, the amount of fine particles made of metal or metal oxide is small compared to the conventional one shown in FIG. 3 in which fine particles made of metal and / or metal oxide are uniformly contained in the resin particles. The addition effect equal to or greater than that is obtained, and therefore the specific gravity of the obtained metal-containing resin particles does not increase more than necessary.
Further, since the resin layer 3 on the outermost surface is a layer containing a polymerizable monomer having an anionic group, preferably sodium styrenesulfonate, the dispersion stability is very excellent.

  Hereinafter, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited to a following example.

<Making fine particles of metal oxide>
60 mL of a 1N ferric chloride aqueous solution and 15 mL of a 2N ferrous chloride aqueous hydrochloric acid solution were mixed and added to 750 mL of a 0.7N aqueous ammonia solution with stirring to precipitate ferric tetroxide. Thereafter, the precipitated triiron tetroxide was collected, added to 90 mL of a 1N-tetramethylammonium hydroxide solution, and further 750 mL of distilled water was added to obtain a triiron tetroxide dispersion (concentration 2% by weight). . Further, 2 mmol of methacryloxypropyltrimethoxysilane was added to 60 mL of the obtained triiron tetroxide dispersion to obtain a dispersion of triiron tetroxide fine particles (average particle size 15 nm) having vinyl groups on the surface.

<Creation of metal-containing resin particles>
In a 1000 mL separable flask equipped with a four-neck separable cover, stirrer, three-way cock, condenser and temperature probe, 750 g of buffer solution (pH 4.4, acetic acid: sodium acetate = 2: 1), 0.45 mol of styrene, After weighing and adding 0.01 mol of methacryloxypropylmethyldimethoxysilane and 0.012 mol of potassium persulfate, the mixture was stirred at 350 rpm and heated to 70 ° C. in a nitrogen atmosphere to initiate polymerization.
After 0.25 hours from the start of polymerization, 120 g of a triiron tetraoxide fine particle dispersion having a vinyl group on the surface was added, and further, 0.19 g of sodium p-styrenesulfonate was added 1.2 hours after the start of polymerization, Thereafter, the polymerization was continued until 7 hours passed from the start of the polymerization to obtain metal-containing resin particles.
The obtained metal-containing resin particles had an average particle size of 0.315 μm, the surface thereof was covered with a resin layer, and the metal-containing resin particles were hardly aggregated. Further, the Cv value of the obtained metal-containing fine particles was 6%.

Metal-containing resin particles of the present invention Conventional metal-containing resin particles whose outermost layer is covered with metal particles Conventional metal-containing resin particles in which metal particles are dispersed in the particles

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core particle 2 Fine particle which consists of metal and / or metal oxide 3 Resin layer

Claims (6)

By starting polymerization in a solution system in which a polymerizable monomer is dispersed in a solvent, resin particles that become core particles are generated, and during the polymerization reaction, a metal having a polymerizable unsaturated group on the surface and / or metal oxidation Production of metal-containing resin particles by adding fine particles made of a product, agglomerating fine particles made of metal and / or metal oxide on the surface of the resin particles, and further adding a polymerizable monomer having an anionic group for subsequent polymerization Method. Fine particles made of a metal and / or metal oxide having a polymerizable unsaturated group on the surface are added to a solution in which the core particles are dispersed in a solvent, and the metal and / or metal oxide are made on the surface of the core particle. A method for producing metal-containing resin particles, in which a polymerizable monomer having an anionic group is added and polymerized. The method for producing metal-containing resin particles according to claim 2, wherein the core particles are resin particles made of polystyrene or poly (meth) acrylic acid ester.
By starting polymerization in a solution system in which a polymerizable monomer having an anionic group and a polymerizable monomer having no anionic group are dispersed in a solvent, resin particles serving as core particles are generated, and the polymerization reaction is in progress In addition, fine particles made of metal and / or metal oxide having a polymerizable unsaturated group on the surface are added, the fine particles made of metal and / or metal oxide are aggregated on the surface of the resin particle, and then the polymerizable monomer is polymerized. A method for producing metal-containing resin particles. The total amount of polymerizable monomers having an anionic group is 0.5-2 mol / m in the solution. ^Three The manufacturing method of the metal containing resin particle of any one of Claims 1-4 which is. The method for producing metal-containing resin particles according to any one of claims 1 to 5, wherein the polymerizable monomer having an anionic group is sodium styrenesulfonate.

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