Composite microparticles and their manufacturing method

Abstract

To provide composite fine particles which have excellent separation property of dye or the like by producing the composite fine particles consisting of inorganic fine particles coated with a polymer compound through one step without requiring any pretreatment step.SOLUTION: Composite fine particles comprise inorganic fine particles which are directly coated with a polymer compound having at least one selected from a group consisting of an amide bond, an imide bond and a nitrogen-containing heterocyclic aromatic ring in the main chain. A dye and / or metal ion adsorbent contain the composite fine particles in which the inorganic fine particles are coated with the polymer compound having at least one selected from the group consisting of the amide bond, the imide bond and the nitrogen-containing heterocyclic aromatic ring in the main chain.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to composite fine particles and a method for producing the same. [Background technology]

[0002] Composite materials that combine polymers and inorganic particles are widely used as highly functional materials that combine the diverse functions and properties of both materials. However, when combining dissimilar materials with significantly different interfacial properties, controlling the affinity and adhesion between the interfaces remains one of the most important technical challenges that must be overcome, and various composite technologies have been investigated to date. Furthermore, composite materials come in a variety of forms, including plate, powder, and fiber, but powder (particle) materials are in high demand due to their excellent moldability.

[0003] Representative composite technologies include (1) a method in which inorganic particles are treated with a silane coupling agent and then reacted with a polymer (see, for example, Patent Documents 1 and 2), (2) a method in which a reactive compound (monomer or low molecular weight compound) is vapor-deposited or chemically modified onto inorganic particles, followed by polymer polymerization, (3) a method in which inorganic particles are immersed in a pre-prepared polymer solution, and (4) a mechanical method in which polymer particles are collided with inorganic particles at high speed in the gas phase. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-254523 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-010664 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above methods (1) to (3) involve two or more steps (pretreatment and compounding), which require a lot of work, time, and cost.

[0006] Furthermore, in the above method (1), a silane coupling agent is used, which means that another compound (third component) is mixed in addition to the constituent material of the desired composite microparticles, which may affect the properties.

[0007] Furthermore, the method (2) above is inevitably a complicated process, requiring the control of reactions during vapor deposition or chemical modification and of high molecular weight polymerization reactions utilizing reaction sites in reactive compounds.

[0008] Furthermore, in the method (3), some types of polymers are insoluble in solvents, or the types of solvents available are very limited. For example, many polyamide compounds polymerized by the method described in JP 2006-257345 A are insoluble in most solvents.

[0009] On the other hand, the above method (4) is a mechanical composite process, so pretreatment is often not required, but it is difficult to control the surface morphology and coating amount of the composite particles produced. However, these controls are essential for imparting functionality (separation ability, etc.) and quality control, so this process is inevitably complicated.

[0010] Based on the above, an object of the present invention is to provide composite microparticles that can be produced in one step by coating inorganic microparticles with a polymer compound without the need for a pretreatment step, and that have excellent separation ability for dyes, etc. [Means for solving the problem]

[0011] The present inventors have conducted extensive research to solve the above-mentioned problems and have found that by polymerizing multiple monomers in a solution containing inorganic particles, composite particles in which inorganic particles are coated with a polymer compound can be produced in one step without the need for a pretreatment step, and composite particles with excellent separation ability for dyes, etc. Based on this finding, the present inventors have conducted further research and completed the present invention. That is, the present invention includes the following features.

[0012] Item 1. Composite fine particles in which inorganic fine particles are directly coated with a polymer compound having at least one bond selected from the group consisting of an amide bond, an imide bond, and a nitrogen-containing heteroaromatic ring in the main chain.

[0013] Item 2. The composite microparticles according to Item 1, wherein the polymer compound is at least one selected from the group consisting of polyamide compounds, polyamideimide compounds, polyesteramide compounds, polyamideurethane compounds, polybenzoxazole compounds, polybenzimidazole compounds, and polyimide compounds.

[0014] Item 3. The composite fine particles according to Item 1 or 2, wherein the inorganic fine particles do not have organic functional groups derived from a silane coupling agent on the surface thereof.

[0015] Item 4. The composite fine particles according to any one of Items 1 to 3, which are a dye and / or a metal ion adsorbent.

[0016] Item 5. The composite fine particles according to any one of Items 1 to 4, wherein the inorganic fine particles have an average particle size of 5 nm to 1 cm.

[0017] Item 6. A dye and / or metal ion adsorbent comprising composite fine particles in which inorganic fine particles are coated with a polymer compound having at least one bond selected from the group consisting of an amide bond, an imide bond, and a nitrogen-containing heteroaromatic ring in the main chain.

[0018] Item 7. The dye and / or metal ion adsorbent according to Item 6, wherein the inorganic fine particles are directly coated with the polymer compound.

[0019] Item 8. The dye and / or metal ion adsorbent according to Item 6 or 7, wherein the inorganic fine particles do not have organic functional groups derived from a silane coupling agent on the surface thereof.

[0020] Item 9. The dye and / or metal ion adsorbent according to any one of Items 6 to 8, wherein the inorganic fine particles have an average particle size of 5 nm to 1 cm.

[0021] Item 10. A method for producing the composite fine particles according to any one of items 1 to 5 or the dye and / or metal ion adsorbent according to any one of items 6 to 9, a step of mixing a first solution obtained by dissolving an acid chloride compound in an organic solvent with a second solution obtained by dissolving a primary amine compound in an organic solvent in the presence of the inorganic fine particles. A manufacturing method comprising:

[0022] Item 11. The production method according to Item 10, wherein the mixing step is further carried out in the presence of a secondary amine compound and / or a tertiary amine compound.

[0023] Item 12. The manufacturing method according to Item 11, wherein the mixing step is a step of adding the inorganic fine particles and the secondary amine and / or tertiary amine compound to the second solution, then adding the first solution, and mixing.

[0024] Item 13. The production method according to Item 11 or 12, wherein the secondary amine compound and / or the tertiary amine compound is soluble in both the first solution and the second solution. [Effects of the Invention]

[0025] According to the present invention, composite fine particles in which inorganic fine particles are coated with a polymer compound can be produced in one step without the need for a pretreatment step. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is an SEM image of the composite fine particles obtained in Example 1. [Figure 2] This is an SEM image of the silica fine particles used as the raw material. [Figure 3] 1 is an SEM image of the composite fine particles obtained in Example 2. [Figure 4] 1 is an SEM image of the composite fine particles obtained in Example 3. [Figure 5] 1 is an SEM image of the composite fine particles obtained in Example 4. [Figure 6]1 is an SEM image of the composite fine particles obtained in Example 5. [Figure 7] This is an SEM image of the alumina fine particles used as the raw material. DETAILED DESCRIPTION OF THE INVENTION

[0027] In this specification, the term "containing" is a concept that encompasses all of "comprise," "consist essentially of," and "consist only of."

[0028] In addition, in this specification, when a numerical range is expressed as "A to B," it means A or more and B or less.

[0029] 1. Composite Microparticles (First Aspect) In the composite fine particles of the present invention, inorganic fine particles are directly coated with a polymer compound having at least one bond selected from the group consisting of an amide bond, an imide bond and a nitrogen-containing heteroaromatic ring in the main chain.

[0030] That is, in the composite particles of the present invention, it is preferable that the inorganic particles do not have organic functional groups on their surfaces due to pretreatment with a silane coupling agent, etc. Therefore, the introduction of the silane coupling agent does not affect the physical properties of the composite particles, and quality control can be easily performed.

[0031] (1-1) Inorganic fine particles The material of the inorganic fine particles used in the present invention is not limited and can be selected from a wide range depending on the application of the final product, etc. Examples include silica, alumina, glass, magnesia, zirconia, titania, ceria, zeolite, calcium oxide, hydroxyapatite, etc. These inorganic fine particles can be used alone or in combination of two or more.

[0032] Among these, silica, alumina, zeolite, etc. are preferred from the viewpoint that composite fine particles in which inorganic fine particles are coated with a polymer compound can be easily produced in one step by the production method described below.

[0033] As described above, the inorganic fine particles used in the present invention preferably do not have organic functional groups derived from a silane coupling agent on their surfaces.

[0034] Such organic functional groups are usually imparted during pretreatment with a silane coupling agent; in other words, it is preferable that the inorganic fine particles used in the present invention have not been pretreated with a silane coupling agent.

[0035] Examples of silane coupling agents include vinyl-based, epoxy-based, styryl-based, methacryloxy-based, acryloxy-based, amino-based, ureido-based, chloropropyl-based, mercapto-based, sulfide-based, and isocyanate-based agents, and examples thereof include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane.

[0036] Therefore, examples of organic functional groups derived from the silane coupling agent that are not present on the surface of the inorganic microparticles include vinyl groups, epoxy groups, styrene groups, methacryloyl groups, acryloxy groups, amino groups, ureido groups, chloropropyl groups, mercapto groups, sulfide groups, and isocyanate groups.

[0037] The shape of the inorganic fine particles is not limited and can be appropriately determined depending on the use of the final product, such as spherical, plate-like, film-like, needle-like, fibrous, flake-like, or scale-like. For example, when the inorganic fine particles are spherical, the average particle size of the inorganic fine particles is usually preferably about 5 nm to 1 cm, and more preferably about 10 nm to 1 mm. The average particle size of the inorganic fine particles is measured using a particle size distribution analyzer.

[0038] (1-2) High molecular compound The polymer compound is not particularly limited as long as it has at least one selected from the group consisting of an amide bond, an imide bond, and a nitrogen-containing heteroaromatic ring (such as an imidazole ring, an oxazole ring, or a thiazole ring) in the main chain, and examples thereof include polyamide compounds, polyamideimide compounds, polyesteramide compounds, polyamideurethane compounds, polybenzoxazole compounds, polybenzimidazole compounds, and polyimide compounds.

[0039] These polymer compounds may be known or commercially available products.

[0040] When the manufacturing method of the present invention described below is used, a polyamide compound, a polyesteramide compound, a polyamideurethane compound, or the like is often obtained on inorganic fine particles by polymerizing an acid chloride and a primary amine compound described below. Thus, if the polyamide compound is obtained and then imidized by a conventional method, a polyamideimide compound, a polyimide compound, or the like can be obtained. Furthermore, if the polyamide compound is obtained and then subjected to a ring-closing reaction by a conventional method, a polybenzoxazole compound, a polybenzimidazole compound, or the like can be obtained. Either case constitutes the present invention.

[0041] (1-3) Composite fine particles In the composite fine particles of the present invention, the inorganic fine particles are directly coated with the polymer compound, i.e., the inorganic fine particles are coated with the polymer compound without any other layer such as an organic functional group derived from a silane coupling agent.

[0042] Therefore, the introduction of the silane coupling agent does not affect the physical properties of the composite particles, and quality control can be easily performed.

[0043] In the composite microparticles of the present invention, the amount of polymer compound coated is not particularly limited. However, from the viewpoints that the inorganic microparticles can be easily coated with the polymer compound in one step without the need for a pretreatment process, and that dyes and metal ions can be easily adsorbed, the amount of polymer compound coated measured by heat treatment at 1000°C (in air) is preferably 0.1 to 80% by mass, and more preferably 0.1 to 70% by mass, where the total amount of the composite microparticles of the present invention is 100% by mass.

[0044] The shape of the composite microparticles of the present invention is not limited and can be appropriately determined depending on the use of the final product, such as spherical, plate-like, film-like, needle-like, fibrous, flake-like, or scale-like shapes. For example, when the composite microparticles of the present invention are spherical, the average particle size of the composite microparticles of the present invention is usually preferably about 5 nm to 1 cm, and more preferably about 10 nm to 1 mm. The average particle size of the composite microparticles of the present invention is measured using a particle size distribution analyzer.

[0045] Such composite microparticles of the present invention can adsorb dyes and metal ions when placed in, for example, a dye solution or a solution containing metal ions, and can be used as a dye and / or metal ion adsorbent.

[0046] In this case, the dyes to be used are not particularly limited and include, for example, rhodamine B, rhodamine 6G, acid red 87, acid red 289, acid red 92, sulforhodamine B, sunset yellow FCF, amaranth, fast green FCF, indigo carmine, methylene blue, brilliant cresyl blue, neutral red, reactive blue 4, Congo red, crystal violet, methyl violet B, and brilliant green. The metal ions to be used are not particularly limited and include, for example, Cr(VI), Fe(II), Co(II), Ni(II), Cu(II), As(V), Se(IV), Sr(II), Pd(II), Ag(I), Cd(II), La(III), Pt(IV), Au(III), and Pb(II). The composite microparticles of the present invention can adsorb one or more of these ions.

[0047] 2. Dye and / or Metal Ion Adsorbent (Second Aspect) The dye and / or metal ion adsorbent of the present invention contains composite fine particles in which inorganic fine particles are coated with a polymer compound having at least one bond selected from the group consisting of an amide bond, an imide bond, and a nitrogen-containing heteroaromatic ring in the main chain.

[0048] (2-1) Inorganic fine particles The material of the inorganic fine particles used in the present invention is not limited and can be selected from a wide range depending on the application of the final product, etc. Examples include silica, alumina, glass, magnesia, zirconia, titania, ceria, zeolite, calcium oxide, hydroxyapatite, etc. These inorganic fine particles can be used alone or in combination of two or more.

[0049] Among these, silica, alumina, zeolite, etc. are preferred from the viewpoint that composite fine particles in which inorganic fine particles are coated with a polymer compound can be easily produced in one step by the production method described below.

[0050] Although it is not excluded that the inorganic microparticles used in the present invention have organic functional groups derived from a silane coupling agent on their surface, it is preferable that they do not have organic functional groups derived from a silane coupling agent on their surface, from the viewpoint that the introduction of a silane coupling agent does not affect the physical properties of the composite microparticles and quality control can be easily performed.

[0051] Such organic functional groups are usually imparted during pretreatment with a silane coupling agent; in other words, it is preferable that the inorganic fine particles used in the present invention have not been pretreated with a silane coupling agent.

[0052] Examples of silane coupling agents include vinyl-based, epoxy-based, styryl-based, methacryloxy-based, acryloxy-based, amino-based, ureido-based, chloropropyl-based, mercapto-based, sulfide-based, and isocyanate-based agents, and examples thereof include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane.

[0053] Therefore, examples of organic functional groups derived from silane coupling agents that are preferably not present on the surface of inorganic fine particles include vinyl groups, epoxy groups, styrene groups, methacryloyl groups, acryloxy groups, amino groups, ureido groups, chloropropyl groups, mercapto groups, sulfide groups, and isocyanate groups.

[0054] The shape of the inorganic fine particles is not limited and can be appropriately determined depending on the use of the final product, such as spherical, plate-like, film-like, needle-like, fibrous, flake-like, or scale-like. For example, when the inorganic fine particles are spherical, the average particle size of the inorganic fine particles is usually preferably about 5 nm to 1 cm, and more preferably about 10 nm to 1 mm. The average particle size of the inorganic fine particles is measured using a particle size distribution analyzer.

[0055] (2-2) High molecular compound The polymer compound is not particularly limited as long as it has at least one selected from the group consisting of an amide bond, an imide bond, and a nitrogen-containing heteroaromatic ring (such as an imidazole ring, an oxazole ring, or a thiazole ring) in the main chain, and examples thereof include polyamide compounds, polyamideimide compounds, polyesteramide compounds, polyamideurethane compounds, polybenzoxazole compounds, polybenzimidazole compounds, and polyimide compounds.

[0056] These polymer compounds may be known or commercially available products.

[0057] When the manufacturing method of the present invention described below is used, a polyamide compound, a polyesteramide compound, a polyamideurethane compound, or the like is often obtained on inorganic fine particles by polymerizing an acid chloride and a primary amine compound described below. Thus, if the polyamide compound is obtained and then imidized by a conventional method, a polyamideimide compound, a polyimide compound, or the like can be obtained. Furthermore, if the polyamide compound is obtained and then subjected to a ring-closing reaction by a conventional method, a polybenzoxazole compound, a polybenzimidazole compound, or the like can be obtained. Either case constitutes the present invention.

[0058] (2-3) Dye and / or metal ion adsorbent In the dye and / or metal ion adsorbent of the present invention, the coating amount of the polymer compound is not particularly limited. However, from the viewpoints of easily coating inorganic fine particles with the polymer compound in one step without the need for a pretreatment step and easily adsorbing dyes and metal ions, the coating amount of the polymer compound measured by heat treatment at 1000°C (in air) is preferably 0.1 to 80 mass%, and more preferably 0.1 to 70 mass%, of the total amount of the dye and / or metal ion adsorbent of the present invention being 100 mass%.

[0059] The shape of the dye and / or metal ion adsorbent of the present invention is not limited and can be appropriately determined depending on the use of the final product, such as spherical, plate-like, film-like, needle-like, fibrous, flake-like, or scale-like shapes. For example, when spherical, the average particle size of the dye and / or metal ion adsorbent of the present invention is usually preferably about 5 nm to 1 cm, and more preferably about 10 nm to 1 mm. The average particle size of the dye and / or metal ion adsorbent of the present invention is measured using a particle size distribution analyzer.

[0060] The dye and / or metal ion adsorbent of the present invention can adsorb dyes and / or metal ions when added to, for example, a dye solution or a solution containing metal ions.

[0061] In this case, the dyes to be used are not particularly limited and include, for example, rhodamine B, rhodamine 6G, Acid Red 87, Acid Red 289, Acid Red 92, sulforhodamine B, Sunset Yellow FCF, amaranth, Fast Green FCF, indigo carmine, methylene blue, brilliant cresyl blue, neutral red, reactive blue 4, Congo red, crystal violet, methyl violet B, and brilliant green. The metal ions to be used are not particularly limited and include, for example, Cr(VI), Fe(II), Co(II), Ni(II), Cu(II), As(V), Se(IV), Sr(II), Pd(II), Ag(I), Cd(II), La(III), Pt(IV), Au(III), and Pb(II). The dye and / or metal ion adsorbent of the present invention can adsorb one or more of these ions.

[0062] 3. Manufacturing method The production method of the present invention is a method for producing the composite fine particles of the present invention or the dye and / or metal ion adsorbent of the present invention, comprising the steps of: a step of mixing a first solution obtained by dissolving an acid chloride compound in an organic solvent with a second solution obtained by dissolving a primary amine compound in an organic solvent in the presence of inorganic fine particles; Furthermore, from the viewpoint of easily coating the inorganic fine particles with the polymer compound, less generation of uncomposite pieces of the polymer compound (small pieces of the polymer compound not coated on the inorganic fine particles, dust, etc.), and easily obtaining only composite fine particles, it is preferable that the mixing step be carried out in the presence of a secondary amine compound and / or a tertiary amine compound, that is, in the presence of inorganic fine particles and a secondary amine compound and / or a tertiary amine compound.

[0063] That is, in the present invention, the acid chloride compound and the primary amine compound are prepared as separate solutions.

[0064] (3-1) First solution The acid chloride compound used in the first solution is not particularly limited, and for example, the same compounds as those used in conventional polymer compound synthesis can be used.

[0065] Examples of the acid chloride compound include acid dichloride compounds, acid trichloride compounds, acid tetrachloride compounds, etc., but generally, acid dichloride compounds or acid trichloride compounds can be preferably used. Examples of the acid chloride compounds include aliphatic acid dichloride compounds such as oxalic acid dichloride, malonic acid dichloride, succinic acid dichloride, fumaric acid dichloride, glutaric acid dichloride, adipic acid dichloride, muconic acid dichloride, sebacic acid dichloride, nonanoic acid dichloride, and undecanoic acid dichloride; alicyclic acid dichloride compounds such as 1,2-cyclopropanedicarboxylic acid dichloride, 1,3-cyclobutanedicarboxylic acid dichloride, 1,3-cyclopentanedicarboxylic acid dichloride, 1,3-cyclohexanedicarboxylic acid dichloride, and 1,4-cyclohexanedicarboxylic acid dichloride; phthalic acid dichloride, isophthalic acid dichloride, terephthalic acid dichloride, 1,4-naphthalenedicarboxylic acid dichloride, 1,5-(9-oxofluorene)dicarboxylic acid dichloride, and 1,4-anthracenedicarboxylic acid dichloride; 1,4-Anthraquinonedicarboxylic acid dichloride, 2,5-biphenyldicarboxylic acid dichloride, 1,5-biphenylenedicarboxylic acid dichloride, 4,4'-biphenyldicarbonyl chloride, 4,4'-methylenedibenzoic acid dichloride, 4,4'-isopropylidenedibenzoic acid dichloride, 4,4'-bibenzyldicarboxylic acid dichloride, 4,4'-stilbenedicarboxylic acid dichloride, 4,4'-transicarboxylic acid Examples of the acid chloride compounds include aromatic acid dichloride compounds such as 4,4'-carbonyldibenzoic acid dichloride, 4,4'-oxydibenzoic acid dichloride, 4,4'-sulfonyldibenzoic acid dichloride, 4,4'-dithiodibenzoic acid dichloride, p-phenylenediacetic acid dichloride, and 3,3'-p-phenylenedipropionic acid dichloride; and acid trichloride compounds such as 1,3,5-benzenetricarbonyl trichloride. These acid chloride compounds can be used alone or in combination of two or more.

[0066] As the acid chloride compound, an acid chloride compound having a functional group can also be used.

[0067] The functional group is not particularly limited as long as it can impart the desired function to the surface of the resulting microparticles. For example, functional groups such as a hydroxyl group (-OH), a carboxyl group (-COOH), an amino group (-NH), an alkenyl group (a group having -CH=CH-), an alkynyl group (a group having -C≡C-), a vinyl ether group (a group having -CH=CH-O-), an amide group (-CONH), a nitrile group (-C≡N), an isocyanate group (-N=C=O), a nitro group (-NO), a sulfonic group (-SO3H), a thiol group (-SH), a crown ether group, and the like, as well as halogenated alkyl groups such as a -CF3 group, a -CCl3 group, and a -CBr3 group, can be mentioned. Note that the acid chloride compound used as a raw material has a -COCl group, but if such groups are present on the surface of the final microparticles, they are included in the functional groups of the present invention.

[0068] These functional groups may be contained alone or in combination of two or more. When one acid chloride compound has two or more functional groups, these functional groups may be the same or different from each other. In the present invention, these functional groups can be appropriately imparted to the particle surface depending on the desired physical properties of the obtained composite particle, the use of the final product, etc.

[0069] When an acid chloride compound having a functional group is used, the acid chloride compound may be any of the above-mentioned compounds having the functional group described above. Examples include 4,4'-(2,2-hexafluoroisopropylidene)diphthalic acid dichloride, 4-nitrophthalic acid dichloride, 3-nitrophthalic acid dichloride, 4-methylphthalic acid dichloride, and tetrachlorophthalic acid dichloride. Acid chloride compounds such as acid dichlorides and acid trichlorides that can be used for polyamideimides (described below) and have the functional group described above can also be used as the acid chloride compound (raw material) of the present invention. 1,3,5-benzenetricarbonyl trichloride, which can be used for synthesizing polyesteramide compounds, can also be used as the acid chloride compound (raw material) of the present invention.

[0070] In the present invention, it is also possible to use an acid chloride compound having a functional group in combination with an acid chloride compound having no functional group. This allows the properties of the resulting composite microparticles to be controlled as desired. In this case, the ratio of the two compounds can be appropriately set depending on the type of functional group, the desired amount of functional group, etc.

[0071] The acid chloride compound can be appropriately selected depending on the desired properties of the resulting composite fine particles. For example, when an aromatic acid dichloride (particularly at least one of terephthalic acid dichloride, 4,4'-biphenyldicarbonyl chloride, and isophthalic acid dichloride) or an aromatic acid trichloride (particularly 1,3,5-benzenetricarbonyl trichloride) is used as the acid chloride compound, it is easy to uniformly coat the inorganic fine particles with the polyamide compound.

[0072] In the present invention, the polymer compound also includes a polyamide-imide compound. Therefore, the acid chloride compound may be any of those used in conventional polyamide-imide synthesis. Examples of acid chloride compounds that may be used include trimellitic acid chloride, pyromellitic acid chloride, oxydiphthalic acid chloride, biphenyl-3,4,3',4'-tetracarboxylic acid chloride, benzophenone-3,4,3',4'-tetracarboxylic acid chloride, diethyl pyromellitate diacyl chloride, diphenylsulfone-3,4,3',4'-tetracarboxylic acid chloride, 4,4'-(2,2-hexafluoroisopropylidene)phthalic acid chloride, m(p)-phenyl-3,4,3',4'-tetracarboxylic acid chloride, cyclobutane-1,2,3,4-tetracarboxylic acid chloride, and 1-carboxymethyl-2,3-5-cyclopentanetricarboxylic acid chloride. These acid chloride compounds may be acid dichlorides, acid trichlorides, or acid tetrachlorides.

[0073] In addition to the acid chloride compound, when precipitating a polyamide-imide compound, as an anhydride of a carboxylic acid, trimellitic dianhydride, pyromellitic dianhydride, oxydiphthalic dianhydride, biphenyl-3,4,3',4'-tetracarboxylic dianhydride, benzophenone-3,4,3',4'-tetracarboxylic dianhydride, diethylpyromellitic diacyl dianhydride, diphenylsulfone-3,4,3',4'-tetracarboxylic dianhydride, 4,4'-(2,2-hexafluoroisopropylidene)diphthalic dianhydride, m(p)-phenyl-3,4,3',4'-tetracarboxylic dianhydride, cyclobutane-1,2,3,4-tetracarboxylic dianhydride, 1-carboxymethyl-2,3-5 cyclopentanetricarboxylic dianhydride, and the like can be used.

[0074] The organic solvent used in the first solution is not particularly limited as long as it substantially dissolves the acid chloride compound but does not dissolve the resulting polymer compound and composite microparticles. Examples include solvents in which secondary amine compounds or tertiary amine compounds are soluble, such as acetone, dioxane, ethyl acetate, methyl acetate, dimethylacetamide, dimethylformamide, acetophenone, acetylacetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, cyclohexanone, toluene, xylene, and tetrahydrofuran. Solvents containing at least one of these can be used. Among these, solvents containing at least one of acetone, dioxane, ethyl acetate, dimethylacetamide, and dimethylformamide are preferred for the first solution. Depending on the type of acid chloride compound used, it may not immediately dissolve in a solvent such as acetone. In such cases, the acid chloride compound can be dissolved in a mixture of a secondary amine compound or a tertiary amine compound with acetone, or the acid chloride compound can be dissolved in a secondary amine compound or a tertiary amine compound first and then dissolved in acetone.

[0075] The concentration of the acid chloride compound in the first solution may be appropriately set depending on the type of acid chloride compound used, the concentration of the second solution, etc., but is usually preferably about 0.001 to 0.2 mol / L, more preferably about 0.0025 to 0.1 mol / L. When the concentration of the acid chloride compound in the first solution is within this range, small pieces of uncomplexed polymer compound (small pieces of polymer compound not coated on inorganic fine particles, dust, etc.) are unlikely to be produced, and only composite fine particles are likely to be obtained.

[0076] (3-2) Second solution The primary amine compound used in the second solution is not particularly limited, and examples thereof include those used in the synthesis of known polymer compounds, such as 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 1,4'-bis(4-aminophenoxy)benzene, 1,3'-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 3,4'-diaminodiphenyl ether, and 4,4'-diaminodiphenyl sulfide. benzene, 3,4-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-methylene-bis(2-chloroaniline), 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl sulfide, 2,6'-diaminotoluene, 2,4-diaminochlorobenzene, 1,2-diaminoanthraquinone, 1,4-diaminoanthraquinone, 3,3'-diaminobenzophenone, 3,4-diaminobenzophenone, 4,4'-diaminobenzophenone, 4,4'-diaminobiphenyl aromatic diamine compounds such as 1,2-diaminomethyl-2,2'-diamino-1,1'-binaphthalene, R(+)-2,2'-diamino-1,1'-binaphthalene, S(+)-2,2'-diamino-1,1'-binaphthalene, 1,3-bis(4-aminophenoxy)alkane, 1,4-bis(4-aminophenoxy)alkane, 1,5-bis(4-aminophenoxy)alkane, and other 1,n-bis(4-aminophenoxy)alkanes (n is 3 to 10), 1,2-bis[2-(4-aminophenoxy)ethoxy]ethane, and 9,9-bis(4-aminophenyl)fluorene; Aliphatic diamine compounds such as 1,4-diaminocyclohexane, 1,2-diaminocyclohexane, bis(4-aminocyclohexyl)methane, and 4,4'-diaminodicyclohexylmethane, as well as 3,4-diaminopyridine and 1,4-diamino-2-butanone can also be used.These may be used alone or in combination of two or more.

[0077] In addition to the diamine compounds, other amine compounds (monoamine compounds, polyamine compounds, etc.) can also be used in the present invention, which can change the properties of the composite fine particles of the present invention.

[0078] The primary amine compound may also be a primary amine compound having a functional group.

[0079] The functional group is not particularly limited as long as it can impart the desired function to the surface of the resulting microparticles. Examples include functional groups such as a hydroxyl group (-OH), a carboxyl group (-COOH), an amino group (-NH), an alkenyl group (a group having -CH=CH-), an alkynyl group (a group having -C≡C-), a vinyl ether group (a group having -CH=CH-O-), an amide group (-CONH), a nitrile group (-C≡N), an isocyanate group (-N=C=O), a nitro group (-NO), a sulfonic group (-SO3H), a thiol group (-SH), and a crown ether group, as well as halogenated alkyl groups such as a -CF3 group, a -CCl3 group, and a -CBr3 group. Although the primary amine compound used as a raw material has a -NH2 group, if such a group is present on the surface of the resulting microparticles, it is included in the functional group of the present invention.

[0080] These functional groups may be contained alone or in combination of two or more. When one primary amine compound has two or more functional groups, these functional groups may be the same or different from each other. In the present invention, these functional groups can be appropriately added to the surface of the fine particles depending on the desired physical properties of the obtained composite fine particles, the use of the final product, etc.

[0081] When using a primary amine compound having a functional group, the primary amine compound having the functional group described above can be used. For example, 1,3-diamino-2-propyl alcohol, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2'-bis(trifluoromethyl)benzidine, 3,3'-bis(trifluoromethyl)benzidine, 4,4'-diaminooctafluorobiphenyl, 2,5-diaminobenzotrifluoride, 3,5-diaminobenzoic acid, 3,4-diaminobenzoic acid, 3,3'-diaminobenzidine, 2,4,6-triaminopyrimidine, 4,4'-diamino-3,3'-dihydroxybiphenyl, 2,4-diamino-6-hydroxypyrimidine, 4,4'-diamino-3,3'-dimethyldiphenylmethane, etc. can be used. In particular, 3,5-diaminobenzoic acid, 4,4'-diamino-3,3'-dihydroxybiphenyl, etc. are preferably used because they facilitate uniform coating of inorganic fine particles with polymeric compounds such as polyamide compounds, improving separation performance for dyes, metal ions, etc.

[0082] In the present invention, a primary amine compound having a functional group and a primary amine compound having no functional group can be used in combination. This can change the properties of the resulting composite fine particles. In this case, the ratio of the two compounds can be appropriately set depending on the type of functional group, the desired amount of functional group, etc.

[0083] The organic solvent used in the second solution is not particularly limited as long as it substantially dissolves the primary amine compound but does not dissolve the resulting polymer compound and composite particles. Examples of solvents that dissolve primary amine compounds include acetone, dioxane, ethyl acetate, methyl acetate, dimethylacetamide, dimethylformamide, acetophenone, acetylacetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, cyclohexanone, toluene, xylene, and tetrahydrofuran. Solvents containing at least one of these can be used. For the second solution, solvents containing at least one of acetone, dioxane, ethyl acetate, dimethylacetamide, and dimethylformamide are preferred. Using a mixed solvent containing multiple solvents can optimize the polarity of the reaction solvent, facilitating coating and composite formation of the polymer compound on the inorganic particles. Depending on the type of primary amine compound used, it may not immediately dissolve in a solvent such as acetone. In such cases, the primary amine compound can be dissolved in a mixture of the primary amine compound and acetone, or the primary amine compound can be dissolved in acetone first.

[0084] The solvent of the second solution may be the same as the solvent of the first solution, or may be different as long as they are compatible with each other.

[0085] The concentration of the primary amine compound in the second solution may be appropriately set depending on the type of diamine compound used, the concentration of the first solution, etc., but is usually preferably about 0.001 to 0.2 mol / L, more preferably about 0.0025 to 0.1 mol / L. When the concentration of the primary amine compound in the second solution is within this range, small pieces of uncomplexed polymer compound (small pieces of polymer compound not coated on inorganic fine particles, debris, etc.) are unlikely to be produced, and only composite fine particles are likely to be obtained.

[0086] (3-3) Secondary amine compound and / or tertiary amine compound In the mixing step of the present invention, as described above, it is preferable to carry out the mixing step in the presence of a secondary amine compound and / or a tertiary amine compound, that is, in the presence of inorganic fine particles and a secondary amine compound and / or a tertiary amine compound, from the viewpoints that it is easy to coat the inorganic fine particles with the polymer compound, that small pieces of uncomplexed polymer compound (small pieces of polymer compound not coated on the inorganic fine particles, scraps, etc.) are not easily generated, and that only composite fine particles are easily obtained.

[0087] The secondary amine compound and the tertiary amine compound are not particularly limited, but are preferably compounds that are soluble in both the first solution and the second solution, and may be liquid (i.e., organic solvent) or solid.

[0088] For example, preferred examples of secondary amine compounds include at least one of heterocyclic secondary amines, alicyclic secondary amines, aliphatic secondary amines, and aromatic secondary amines, and preferred examples of tertiary amine compounds include at least one of heterocyclic tertiary amines, alicyclic tertiary amines, aliphatic tertiary amines, and aromatic tertiary amines.

[0089] More specifically, examples of the heterocyclic secondary amine compound include piperidine, pyrrole, pyrrolidine, piperazine, 3-pyrroline, etc. These heterocyclic secondary amine compounds can be used alone or in combination of two or more.

[0090] Examples of heterocyclic tertiary amines include pyridine, quinoline, isoquinoline, pyrazine, N,N'-dimethylpiperazine, pyrimidine, pyridazine, 1,2-dimethylimidazole, 1-methylimidazole, etc. These heterocyclic tertiary amine compounds can be used alone or in combination of two or more.

[0091] In the present invention, heterocyclic amine compounds having both a secondary amino group and a tertiary amino group in the same molecule can also be used. Examples of heterocyclic amine compounds having both a secondary amino group and a tertiary amino group in the same molecule include imidazole, pyrazole, and purine. These heterocyclic amine compounds belong to both heterocyclic secondary amine compounds and heterocyclic tertiary amine compounds.

[0092] Examples of alicyclic secondary amine compounds include 2-azabicyclo[2.2.2]octane (isoquinuclidine), 3,7-diazabicyclo[3.3.1]nonane (bispidine), 9-azabicyclo[3.3.1]nonane (granatanin), 2,5-diazabicyclo[2.2.1]heptane, cyclohexylamine, etc. These alicyclic secondary amine compounds can be used alone or in combination of two or more.

[0093] Examples of alicyclic tertiary amine compounds include 1,4-diazabicyclo[2.2.2]octane (triethylenediamine), 1-azabicyclo[2.2.2]octane (quinuclidine), 1-azabicyclo[3.2.2]nonane (homoquinuclidine), 9-methyl-9-azabicyclo[3.3.1]nonane (granatane), N,N-dimethyl-cyclohexylamine, N,N-diethyl-cyclohexylamine, etc. These alicyclic tertiary amine compounds can be used alone or in combination of two or more.

[0094] Examples of the aliphatic secondary amine compound include ethylmethylamine, diethylamine, di-iso-amylamine, di-n-amylamine, dibenzylamine, 2-(N-methylamino)heptane, etc. These aliphatic secondary amine compounds can be used alone or in combination of two or more.

[0095] Examples of aliphatic tertiary amine compounds include trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, tributylamine, N-methyl-diethylamine, N-ethyl-dimethylamine, N-ethyl-diamylamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N",N"-pentamethyldiethylenetriamine, and N,N,N',N",N"-pentamethyldipropylenetriamine. These aliphatic tertiary amine compounds can be used alone or in combination of two or more.

[0096] Examples of aromatic secondary amine compounds include N-methylaniline, N-isobutylaniline, N-ethylaniline, diphenylamine, etc. These aromatic secondary amine compounds can be used alone or in combination of two or more.

[0097] Examples of aromatic tertiary amine compounds include N,N-dimethylaniline, N,N-diethylaniline, N-ethyl-N-methylaniline, triphenyleneamine, benzyldimethylamine, etc. These aromatic tertiary amine compounds can be used alone or in combination of two or more.

[0098] Among these, heterocyclic tertiary amines and / or alicyclic tertiary amines are preferred, and pyridine and / or triethylenediamine are particularly preferred, from the viewpoint of facilitating the production of composite fine particles with a high degree of polymerization of the polymer compound.

[0099] (3-4) Mixing process In the present invention, a first solution obtained by dissolving the acid chloride compound in an organic solvent and a second solution obtained by dissolving the primary amine compound in an organic solvent are mixed in the presence of the inorganic fine particles and, if necessary, the secondary amine compound and / or tertiary amine compound.

[0100] The mixing ratio of the first solution to the second solution can be changed as appropriate depending on the types of acid chloride compound and primary amine compound, the concentrations of each solution, etc., but they can usually be mixed at a ratio of acid chloride compound:primary amine compound = 1:0.5 to 2 (molar ratio), preferably 1:0.5 to 1.5 (molar ratio).

[0101] The secondary amine compound and / or tertiary amine compound used in the mixing step may contain an organic solvent other than the secondary amine compound and the tertiary amine compound. Examples of the organic solvent include those described in detail for the first solution and the second solution.

[0102] When the secondary amine compound and the tertiary amine compound are solids, they may be dissolved in a solvent such as acetone to be used as a solution, or the solid may be directly dissolved in the first solution or the second solution.

[0103] The secondary amine compound and / or tertiary amine compound can be added to the first solution and / or the second solution immediately before mixing the first solution and the second solution, but it is preferable to add it to the second solution in advance from the viewpoint of easily preventing a decrease in the reactivity of the acid chloride. That is, it is preferable to add the inorganic fine particles and the secondary amine and / or tertiary amine compound to the second solution, and then add the first solution and mix them.

[0104] The amount of secondary amine compound and / or tertiary amine compound added may be appropriately determined depending on the types of acid chloride compound and primary amine compound used, the concentrations of the first and second solutions, the desired (average) particle size of the resulting composite microparticles, etc. However, when the secondary amine compound or tertiary amine compound is an organic solvent, the amount is usually about 1 to 100 mL, more preferably about 1 to 50 mL, per 100 mL of the first or second solution. When the secondary amine compound or tertiary amine compound is a solid, the amount is usually about 0.00002 to 0.01 mol, more preferably about 0.0001 to 0.005 mol, per 100 mL of the first or second solution.

[0105] In the mixing step, it is particularly preferable to produce composite microparticles by precipitating a polymer compound such as polyamide while stirring. Stirring can be carried out by a known stirring method (stirring device). In the present invention, stirring may be carried out by ultrasonic waves or by a conventional method using a magnetic stirrer or the like. Ultrasonic stirring promotes polymer polymerization and shortens the reaction time. For ultrasonic stirring, known ultrasonic devices (e.g., ultrasonic cleaners) and operating conditions can be used as they are. The frequency of the ultrasonic waves can be appropriately set depending on the desired (average) particle size, etc., and can usually be about 28 to 1000 kHz, preferably about 28 to 100 kHz.

[0106] The temperature in the mixing step is not particularly limited and can usually be about 0 to 100°C, preferably about 0 to 40°C. Cooling the mixed solution to slow down the reaction rate makes it less likely that small pieces of uncomposite polymer compound (small pieces of polymer compound not coated on inorganic fine particles, debris, etc.) will be produced, and it is easier to obtain only composite fine particles, so the temperature in the mixing step is more preferably about room temperature (25°C) or lower, and particularly about 0 to 20°C. Stirring can be carried out until precipitation of the polyamide is substantially complete.

[0107] The composite fine particles obtained in the mixing step can be collected by solid-liquid separation according to a known method such as centrifugation.

[0108] When a polyamide-imide compound is to be deposited on inorganic fine particles as a polymeric compound, an acid chloride compound such as trimellitic acid chloride, which is used in polyamide-imide synthesis, can be used to condense the carboxyl groups and amide groups present in the fine particles obtained in the mixing step to form imidized particles. The imidization method is not particularly limited, but in the present invention, the following methods can be used: (i) dispersing the compound in an organic solvent and heating it (usually at 130°C or higher, preferably at about 130 to 250°C) to form imidized particles (thermal ring closure); (ii) imidizing it by a chemical reaction in an organic solvent (chemical ring closure); or (iii) heating it in a nitrogen atmosphere (usually at 300°C or higher, preferably at about 350 to 450°C) to form imidized particles (thermal ring closure). [Example]

[0109] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the embodiments of the examples.

[0110] In the examples, ultrasonic stirring was performed using an ultrasonic cleaner "Triple Frequency Ultrasonic Cleaner VS-100 III."

[0111] The evaluations in the present invention were measured as follows.

[0112] (1) Form The morphology was observed using a scanning electron microscope (SEM) ("SU8230" manufactured by Hitachi, Ltd.).

[0113] (2)Separation power (dye) The absorbance of the aqueous solution before and after adsorption was measured using an ultraviolet-visible spectrophotometer (manufactured by JASCO). After baseline correction of the obtained spectrum, the absorbance at 554 nm was read and used as the concentration of the aqueous solution. The adsorption removal rate was calculated using the following formula. Adsorption removal rate (%)=(C0-C48H) / C0×100 C0: Initial concentration (solution concentration before adsorption) C48H: concentration after 48 hours (solution concentration after adsorption).

[0114] (metal ions) The metal ion concentrations in the aqueous solution before and after adsorption were measured using an inductively coupled plasma optical emission spectrometer (manufactured by Thermo Fisher Scientific Co., Ltd.). The adsorption removal rate was calculated using the following formula. Adsorption removal rate (%)=(C0-C24H) / C0×100 C0: Initial concentration (metal concentration before adsorption) C24H: concentration after 24 hours (metal ion concentration after adsorption).

[0115] Example 1: Composite microparticles with polyamide deposited directly on the silica surface As a first solution, 50 mL of a solution was prepared by dissolving 0.0005 mol of 1,3,5-benzenetricarbonyl trichloride in acetone, and as a second solution, 50 mL of a solution was prepared by dissolving 3,5-diaminobenzoic acid in a mixed solvent of acetone and dimethylacetamide (composition ratio = 6:4 (volume ratio)).

[0116] Then, 0.125 g of silica microparticles (average particle size 5 μm) and 3 mL of pyridine were added to the second solution and stirred, and then the first solution was added. The mixture was then stirred with ultrasound at a frequency of 28 kHz for 30 minutes and then with a magnetic stirrer at room temperature for 24 hours to allow the mixture to react.

[0117] The product was observed under a scanning electron microscope (SEM), and it was confirmed that the resulting composite microparticles (Fig. 1) had the same shape as silica microparticles (Fig. 2).

[0118] Infrared spectroscopic analysis also revealed bands derived from polyamide as well as silica, and it was confirmed that the amount of polyamide coating was 3.6% by mass of the total weight of the composite particles after heat treatment at 1000°C (in air).

[0119] Comparative Example 1: Silica Silica fine particles (average particle size 5 μm) (FIG. 2) were used as the fine particles of Comparative Example 1.

[0120] Example 2: Composite microparticles with polyamide deposited directly on the silica surface As the first solution, 50 mL of a solution was prepared by dissolving 0.0005 mol of 1,3,5-benzenetricarbonyl trichloride in acetone, and as the second solution, 50 mL of a solution was prepared by dissolving m-phenylenediamine in a mixed solvent of acetone and dimethylacetamide (composition ratio = 6:4 (volume ratio)).

[0121] Then, 0.125 g of silica microparticles (average particle size 5 μm) and 3 mL of pyridine were added to the second solution and stirred, and then the first solution was added. The mixture was then stirred with ultrasound at a frequency of 28 kHz for 30 minutes and then with a magnetic stirrer at room temperature for 24 hours to allow the mixture to react.

[0122] The product was observed under a scanning electron microscope (SEM), and it was confirmed that the resulting composite microparticles (Fig. 3) had the same shape as the silica microparticles (Fig. 2).

[0123] Infrared spectroscopic analysis also revealed bands derived from silica and polyamide, and it was confirmed that the amount of polyamide coating was 4.3 mass % of the total weight of the composite particles after heat treatment at 1000°C (in air).

[0124] Example 3: Composite microparticles with polyesteramide deposited directly on the silica surface As the first solution, 50 mL of a solution was prepared by dissolving 0.0005 mol of 1,3,5-benzenetricarbonyl trichloride in acetone, and as the second solution, 50 mL of a solution was prepared by dissolving 4,4'-diamino-3,3'-dihydroxybiphenyl in a mixed solvent of acetone and dimethylacetamide (composition ratio = 2:8 (volume ratio)).

[0125] Then, 0.125 g of silica microparticles (average particle size 5 μm) and 3 mL of pyridine were added to the second solution and stirred, and then the first solution was added. The mixture was then stirred with ultrasound at a frequency of 28 kHz for 30 minutes and then with a magnetic stirrer at room temperature for 24 hours to allow the mixture to react.

[0126] The product was observed under a scanning electron microscope (SEM), and it was confirmed that the obtained composite microparticles (Fig. 4) had the same shape as the silica microparticles (Fig. 2).

[0127] Infrared spectroscopic analysis also revealed bands derived from polyamide as well as silica, and it was confirmed that the amount of polyamide coating was 1.4 mass % of the total weight of the composite particles after heat treatment at 1000°C (in air).

[0128] Example 4: Composite microparticles with polyamide deposited directly on the silica surface As a first solution, 50 mL of a solution was prepared by dissolving 0.0005 mol of 1,3,5-benzenetricarbonyl trichloride in acetone, and as a second solution, 50 mL of a solution was prepared by dissolving 3,5-diaminobenzoic acid in a mixed solvent of acetone and dimethylacetamide (composition ratio = 6:4 (volume ratio)).

[0129] Then, 0.125 g of silica microparticles (average particle size 5 μm) was added to the second solution and stirred, and then the first solution was also added. The mixture was then stirred with ultrasound at a frequency of 28 kHz for 30 minutes and then with a magnetic stirrer at room temperature for 24 hours to allow the mixture to react.

[0130] The product was observed under a scanning electron microscope (SEM), and it was confirmed that the obtained composite microparticles (Fig. 5) had the same shape as the silica microparticles (Fig. 2).

[0131] Infrared spectroscopic analysis also revealed bands derived from silica and polyamide, and it was confirmed that the amount of polyamide coating was 3.9% by mass of the total weight of the composite particles after heat treatment at 1000°C (in air).

[0132] Example 5: Composite microparticles with polyamide deposited directly on the alumina surface As a first solution, 50 mL of a solution was prepared by dissolving 0.0005 mol of 1,3,5-benzenetricarbonyl trichloride in acetone, and as a second solution, 50 mL of a solution was prepared by dissolving 3,5-diaminobenzoic acid in a mixed solvent of acetone and dimethylacetamide (composition ratio = 6:4 (volume ratio)).

[0133] Then, 0.125 g of silica microparticles (average particle size 5 μm) and 3 mL of pyridine were added to the second solution and stirred, and then the first solution was added. The mixture was then stirred with ultrasound at a frequency of 28 kHz for 30 minutes and then with a magnetic stirrer at room temperature for 24 hours to allow the mixture to react.

[0134] The product was observed under a scanning electron microscope (SEM), and it was confirmed that the obtained composite microparticles (Fig. 6) had the same shape as the alumina microparticles (Fig. 7).

[0135] Infrared spectroscopic analysis also revealed bands derived from polyamide as well as alumina, and it was confirmed that the amount of polyamide coated by heat treatment at 1000°C (in air) was 3.1% by mass of the total weight of the composite particles.

[0136] Comparative Example 2: Alumina Alumina fine particles (average particle size 100 nm) (FIG. 7) were used as the fine particles of Comparative Example 2.

[0137] Test Example 1: Resolution (Rhodamine 6G) 80 mg of the composite microparticles obtained in Example 1 were dispersed in 160 mL of a 3.5 mg / L aqueous solution of rhodamine 6G (pH 7), and the solution was stirred at room temperature with a magnetic stirrer for 48 hours. UV-visible spectroscopic analysis of the resulting solution revealed that the adsorption and removal rate of rhodamine 6G was 99%.

[0138] On the other hand, the adsorption and removal rate of uncoated silica fine particles (Comparative Example 1) was 47%, demonstrating a significant coating effect.

[0139] Test Example 2: Resolution (Rhodamine B) 80 mg of the composite microparticles obtained in Example 2 were dispersed in 160 mL of a 3.5 mg / L aqueous solution of rhodamine B (pH 7), and the solution was stirred at room temperature with a magnetic stirrer for 48 hours. UV-visible spectroscopic analysis of the resulting solution revealed that the adsorption and removal rate of rhodamine B was 85%.

[0140] On the other hand, the adsorption and removal rate of uncoated silica fine particles (Comparative Example 1) was 15%, demonstrating a significant coating effect.

[0141] Test Example 3: Resolution (Rhodamine B) 80 mg of the composite microparticles obtained in Example 3 were dispersed in 160 mL of a 3.5 mg / L aqueous solution of rhodamine B (pH 7), and the solution was stirred at room temperature with a magnetic stirrer for 48 hours. UV-visible spectroscopic analysis of the resulting solution revealed that the adsorption and removal rate of rhodamine B was 77%.

[0142] On the other hand, the adsorption and removal rate of uncoated silica fine particles (Comparative Example 1) was 15%, demonstrating a significant coating effect.

[0143] Test Example 4: Resolution (Rhodamine 6G) 80 mg of the composite microparticles obtained in Example 4 were dispersed in 160 mL of a 3.5 mg / L aqueous solution of rhodamine 6G (pH 7), and the solution was stirred at room temperature with a magnetic stirrer for 48 hours. UV-visible spectroscopic analysis of the resulting solution revealed that the adsorption and removal rate of rhodamine 6G was 100%.

[0144] On the other hand, the adsorption and removal rate of uncoated silica fine particles (Comparative Example 1) was 47%, demonstrating a significant coating effect.

[0145] Test Example 5: Resolution (Rhodamine B) 80 mg of the composite microparticles obtained in Example 5 were dispersed in 160 mL of a 3.5 mg / L aqueous solution of rhodamine B (pH 7), and the solution was stirred at room temperature with a magnetic stirrer for 48 hours. UV-visible spectroscopic analysis of the resulting solution revealed that the adsorption and removal rate of rhodamine B was 73%.

[0146] On the other hand, the adsorption and removal rate of the uncoated alumina fine particles (Comparative Example 2) was 36%, demonstrating a significant coating effect.

[0147] Test Example 6: Separation ability (copper ions) 80 mg of the composite microparticles obtained in Example 1 were dispersed in 40 mL of a 10 ppm copper nitrate aqueous solution (pH 5.5), and the solution was stirred for 24 hours in a thermostatic shaking water bath at 30°C. Inductively coupled plasma atomic emission spectroscopy analysis was performed on the resulting solution, and the adsorption and removal rate of copper ions was found to be 19%.

[0148] On the other hand, the adsorption and removal rate of uncoated silica fine particles (Comparative Example 1) was 0%, demonstrating a significant coating effect.

Claims

1. Composite fine particles, in which inorganic fine particles are directly coated with a polymer compound having at least one selected from the group consisting of an amide bond and a nitrogen-containing heteroaromatic ring in the main chain, the polymer compound is a polymer compound obtained by polymerizing an acid chloride compound and a primary amine compound, The composite fine particles, wherein the acid chloride compound is an acid dichloride compound or an acid trichloride compound.

2. 2. The composite microparticle according to claim 1, wherein the polymer compound is at least one selected from the group consisting of polyamide compounds, polyamideimide compounds, polyesteramide compounds, polyamideurethane compounds, polybenzoxazole compounds, and polybenzimidazole compounds.

3. 3. The composite fine particles according to claim 1, wherein the inorganic fine particles do not have organic functional groups derived from a silane coupling agent on the surface thereof.

4. The composite fine particles according to any one of claims 1 to 3, which are an adsorbent for adsorbing dyes and / or metal ions.

5. 5. The composite particles according to claim 1, wherein the inorganic particles have an average particle size of 5 nm to 1 cm.

6. An adsorbent for adsorbing dyes and / or metal ions, comprising composite fine particles in which inorganic fine particles are coated with a polymer compound having at least one kind selected from the group consisting of an amide bond and a nitrogen-containing heteroaromatic ring in the main chain, the polymer compound is a polymer compound obtained by polymerizing an acid chloride compound and a primary amine compound, the acid chloride compound is an acid dichloride compound or an acid trichloride compound, and the inorganic fine particles do not have an organic functional group derived from a silane coupling agent on the surface thereof; An adsorbent that adsorbs dyes and / or metal ions.

7. The adsorbent for adsorbing dyes and / or metal ions according to claim 6 , wherein the inorganic fine particles are directly coated with the polymer compound.

8. 8. The adsorbent for adsorbing dyes and / or metal ions according to claim 6, wherein the inorganic fine particles have an average particle size of 5 nm to 1 cm.

9. A method for producing the composite fine particles according to any one of claims 1 to 5 or the adsorbent for adsorbing dyes and / or metal ions according to any one of claims 6 to 8, comprising the steps of: a step of mixing a first solution obtained by dissolving an acid chloride compound in an organic solvent with a second solution obtained by dissolving a primary amine compound in an organic solvent in the presence of the inorganic fine particles. A manufacturing method comprising:

10. The production method according to claim 9 , wherein the mixing step is further carried out in the presence of a secondary amine compound and / or a tertiary amine compound.

11. The manufacturing method according to claim 10, wherein the mixing step is a step of adding the inorganic fine particles and the secondary amine and / or tertiary amine compound to the second solution, then adding the first solution, and mixing.

12. The method according to claim 10 or 11, wherein the secondary amine compound and / or the tertiary amine compound is soluble in both the first solution and the second solution.

Images