JP4574215B2 - Method for producing polymer-coated particle powder and polymer-coated inorganic particle - Google Patents

Description

  The present invention relates to a method for producing a powder comprising particles coated with a polymer, and a novel polymer-coated inorganic oxide particle obtained by the method.

  Inorganic oxide particles such as silica are excellent in mechanical strength, have high chemical stability, and are easily available in various shapes and sizes at low cost. Used for various applications such as semiconductor sealing resin, dental resin, various rubber packing materials, high performance liquid chromatography (HPLC) column packing materials, film anti-blocking agents, toner external additives, etc. Yes.

  When using inorganic oxide particles, the surface of the inorganic oxide silica particles is generally coated with various substances according to the application and purpose, and the dispersibility and miscibility are improved, or the function is improved. It is done to give sex. As a typical technique for such surface modification, there is a surface treatment with a silane coupling agent. As the silane coupling agent, those having various functional groups such as an alkyl group, a mercapto group, an amino group, a quaternary ammonium group, a sulfonic acid group, an epoxy group, a methacryloxy group, and a vinyl group have been proposed. (See, for example, Patent Documents 1 and 2), many have already been put to practical use.

  On the other hand, various methods for introducing functional groups into particles by a treatment other than a coupling agent such as a silane coupling agent have been proposed. For example, a compound having a vinyl group is obtained by coating inorganic oxide particles with a cyclic siloxane having a Si—H group, and then reacting the Si—H group with a compound having a vinyl group using a platinum catalyst. Has been proposed (see, for example, Patent Documents 3 and 4).

  In order to impart various functionalities, various methods for imparting functionality by coating inorganic oxide particles with a vinyl polymer have been proposed. As a method of coating inorganic oxide particles with a vinyl-based polymer, after coating with a vinyl-based polymerizable monomer, the monomer is polymerized, and a method of directly coating with a vinyl-based polymer. Broadly divided.

  For example, as a method of polymerizing the monomer after adsorbing a vinyl polymerizable monomer and coating the particle, colloidal silica particles can be used as a method for producing particles for white pigment used in paints and the like. A hollow particle is proposed that is dispersed in a polymer, coated and polymerized with a carboxylic acid-based vinyl monomer such as acrylic acid, and further coated and polymerized with a vinyl-based monomer such as methyl methacrylate or styrene. (For example, see Patent Document 5). In addition, as a method for producing filler particles for ion exchange liquid chromatography, an unsaturated carboxylic acid such as maleic acid and a polyvinyl compound copolymerizable with the unsaturated carboxylic acid (pentaerythritol tetraacrylate, divinyl) are used in a solution. Benzene etc.) and silica particles are added to adjust the suspension, concentrated and dried to form a film comprising an unsaturated carboxylic acid and a polyvinyl compound on the silica surface, and further polymerized by heating to form a crosslinked ion exchange composition As a method for forming coated particles for spacers of liquid crystal display devices (for example, see Patent Document 6), silica-based particles are treated with a vinyl-based silane coupling agent, and then this is dissolved in a polar solvent. Disperse, add monofunctional vinyl monomer to this, polymerize it and coat with non-crosslinked vinyl polymer How to obtain the particles (e.g., Patent Document 7 references) it has been proposed.

  On the other hand, as a method of directly coating with a polymer, for example, as a method for producing coated particles for spacers of a liquid crystal display device, a vinyl polymer is dispersed in a solvent, and this is mixed with silica particles. A method of coating (for example, see Patent Document 8), a method in which silica-based particle powder and polymer powder are mixed by a wet or dry method using a ball mill or the like, and a resin layer is formed on the particle surface by mechanical stress (for example, Patent Documents 9, 10) have been proposed.

JP-A-6-199621 JP 9-48610 A Japanese Patent Laid-Open No. 10-267908 JP-A-8-105874 JP-A-3-281579 JP-A-5-96184 Japanese Patent Laid-Open No. 10-226512 JP-A-5-181144 Japanese Patent Laid-Open No. 9-80445 JP 63-94224 A

  The silane coupling agent has a Si—X produced by hydrolysis of Si—X (X is a halogen atom, an alkoxy group, etc.), and M—OH groups (M is an inorganic oxide) present on the surface of the inorganic oxide particles. By reacting with the metal element constituting the product particle, it is bonded onto the particle. Therefore, the treatment amount of the silane coupling agent greatly depends on the surface area of the particles to be treated and the amount of M-OH groups. For this reason, even if it is going to introduce | transduce a various functional group to an inorganic oxide particle, there exists a problem that the quantity does not increase so much. Further, since the silane coupling agent does not completely react with the M-OH group on the surface of the inorganic oxide particles, it may cause hydrolysis or the like under severe conditions.

  Even in the method of coating with a cyclic siloxane having a Si-H group and then reacting with a compound having a vinyl group, the number of functional groups that can be introduced is limited. There is a problem that it is difficult to remove.

  In the method of dispersing inorganic oxides such as silica particles in a solvent and adsorbing and polymerizing vinyl monomers in this dispersion, the formed coating layer can be made relatively uniform and its thickness Since it is relatively easy to control, there is an advantage that a large amount of functional groups can be introduced. However, in this method, there are not a few vinyl monomers that are polymerized outside the particle surface. Therefore, the loss of the vinyl monomer is large, and further, polymer particles of the vinyl monomer polymerized on the surface other than the particle surface may be generated and mixed. Further, since the polymerization is performed in a solvent, the vinyl monomer is easily polymerized in a state in which the solvent is taken in, and the resulting coating layer of the polymer is likely to be rough. Furthermore, when it coat | covers with the vinyl polymer which has an ionic group, it is difficult to raise the functional group density by ionic repulsion. Furthermore, in order to obtain a cross-linked polymer coating, when a plurality of types of polymerizable monomers are used, such as a cross-linking agent, the distribution coefficient of these monomers on the particle surface and the solvent may be different. In many cases, the composition ratio of the obtained polymer is different from the charged value, and control is also required for the control. In particular, in order to obtain a crosslinked polymer having a highly hydrophilic functional group such as a quaternary ammonium base or a sulfonic acid group, a polymerizable monomer having these functional groups is used in combination with a crosslinking agent. However, since the monomer used as a crosslinking agent is usually a hydrophobic compound, the distribution tendency is completely different, and in fact, particles coated with a crosslinked polymer having such a functional group cannot be obtained. There wasn't.

  In the method of coating a polymer that has been polymerized in advance, the problem of generation of polymer particles and the charged value is unlikely to occur. However, in order to dissolve in a solvent, it is necessary to use a non-crosslinked polymer to obtain a crosslinked polymer. In many cases, a complicated operation is often required, and it is also difficult to adjust the degree of crosslinking. On the other hand, the method of directly coating with a cross-linked polymer requires a strong mechanical stress, which is not only energetically disadvantageous, but also particles may be crushed when this stress is applied.

  Furthermore, in the method using such a solvent, steps such as filtration, washing, and drying are required as post-processes, which are industrially complicated, and it is difficult for the particles to be crushed in these processes. In many cases, it aggregates so strongly.

  Accordingly, there has been a demand for providing a method that can easily provide a coating layer having a high thickness and a high density, has few by-products, and is simple in operation and easy to manufacture industrially.

  As a result of diligent investigations to solve the above problems, the present inventors have found that a good polymer film can be obtained by carrying out a dry process rather than dispersing inorganic particles in a solvent, and further studies are made. As a result of the progress, the present invention was completed.

That is, in the present invention, the inorganic particle powder is brought into contact with a polymerizable monomer having a radical polymerizable unsaturated double bond under stirring, and the polymerizable monomer is added to the particles constituting the powder. It is a method for producing polymer-coated particle powder, comprising a step of adsorbing and a step of polymerizing the adsorbed polymerizable monomer.

  The present invention also provides polymer-coated inorganic oxide particles that could not be produced by conventional methods.

  According to the production method of the present invention, a powder composed of particles having various functional groups with few aggregates and by-products can be produced by a simple operation and at low cost. In addition, the thickness of the coating layer having a functional group can be easily controlled, and particles having a functional group can be obtained at a much higher concentration than a method in which a functional group is directly introduced by a silane coupling agent. Furthermore, it is possible to provide new particle powder that could not be produced by the method of dispersing particles in a solvent.

  In the method for producing a powder according to the present invention, a powder comprising particles having a structure in which core particles are coated with a polymer is produced. In the following, the core particle is referred to as a core particle, and a particle obtained by coating the core particle with a polymer is referred to as a coated particle. In addition, the term “powder” means an aggregate of these particles.

  The core particles are not particularly limited, and may be appropriately selected depending on the use of the coated particle powder obtained by the production method of the present invention, whether organic particles or inorganic particles, or organic-inorganic composite particles. Moreover, it may be an artificially synthesized or natural mineral.

  In terms of obtaining coated particles having various functions and physical properties by combining the physical properties of the polymer (organic layer) present as the coating layer and the physical properties of the core particles, the core particles are preferably inorganic particles, in particular, the particle diameter, Inorganic oxide particles are particularly preferred in that various types having different specific surface areas, pore volumes, shapes, etc. are readily available and are excellent in chemical stability.

  Examples of such inorganic oxide particles include silicon, titanium, aluminum, zirconium, tin, lead, iron, zinc and other metals or metalloid single oxides or composite oxides. As the composite oxide, those containing an alkali metal or alkaline earth metal such as sodium, potassium, magnesium and calcium are also suitable. Among these, a silicon single oxide or a composite oxide containing silicon as a constituent element (hereinafter referred to as a silicon-based oxide) is particularly excellent in scientific stability and easily available in various properties. ) Is preferred.

  More specific examples of silicon-based oxides include silicas such as quartz, precipitated silica, fumed silica, sol-gel silica; silica-titania, silica-zirconia, silica-barium oxide, silica-alumina, silica-calcia, silica -Strontium oxide, silica-magnesia, silica-titania-sodium oxide, silica-titania-potassium oxide, silica-zirconia-sodium oxide, silica-zirconia-potassium oxide, silica-alumina-sodium oxide, or silica-alumina-potassium oxide And complex oxides such as calcium silicate, talc, zeolite, and montmorillonite.

  The average particle size and particle size distribution of the core particles may be appropriately selected as necessary, and are not particularly limited. From the viewpoint of dispersibility in various resins and solvents, the average primary particle size is preferably 0.005 to 300 μm, and more preferably 0.005 to 100 μm. In particular, the production method of the present invention is suitable for 0.005 to 10 μm core particles in that the particles are easily agglomerated when dispersed in a solvent and the effect of the present invention is hardly agglomerated. . The shape of the core particle is not particularly limited and may be appropriately selected according to the purpose of use, and can be applied to any shape of core particle such as a spherical shape, a plate shape, a layer shape, a whisker shape, or an indeterminate shape. is there.

  The greatest feature of the present invention is that when the above-mentioned core particles are brought into contact with the polymerizable monomer described later, it is carried out in a powder state. When contacting with the polymerizable monomer, it is difficult to control the thickness and chemical composition of the coating layer if it is carried out in a non-powder state such as a suspension or paste by dispersing in a solvent. A coating layer may not be obtained depending on the type of polymerizable monomer used (or the type of target polymer). Furthermore, there is a problem that it is necessary to separate particles from the solvent as a post-process.

  In the present invention, it is also essential to bring the core particles into contact with the polymerizable monomer while stirring. Without stirring, the coating layer will be non-uniform. The stirring method is not particularly limited, and any known method may be used as long as particles can be floated by the stirring. For example, it may be directly mechanically stirred using a Henschel mixer or the like, or may be agitated by blowing a high-speed air stream, or a method of giving vibration or swinging from the outside. The stirring speed in the case of direct mechanical stirring cannot be generally specified depending on the material, shape, and particle diameter of the core particles, but generally it may be about 100 to 3000 rpm.

  In the production method of the present invention, a polymerizable monomer is brought into contact with and adsorbed on the core particles. Unlike the conventionally known methods, in the present invention, since the core particles are not dispersed in the solvent, the phenomenon that the polymerizable monomer to be used is hardly adsorbed while being dissolved in the solvent does not occur. For efficient adsorption, it may be preferable to modify the surface of the core particle in accordance with the physical properties of the polymerizable monomer.

  Specifically, the polymerizable monomer to be adsorbed (in the case of a mixture, the main component polymerizable monomer) is a hydroxyl group, carboxyl group, phosphonic acid group, phosphoric acid group, sulfonic acid group. Have hydrophilic groups (hereinafter also referred to simply as hydrophilic groups) that can be ionically dissociated in water, such as amino groups and ammonium groups (and corresponding bases, if present). In the case of a compound that is at least%, it is generally preferable to use particles having a water / n-hexane dispersibility tendency on the water side as the core particles. In particular, when the compound has a strongly hydrophilic group such as a sulfonic acid group, a sulfonic acid group, or an ammonium base, and has a solubility in water of 5% by mass or more and a solubility in n-hexane of 5% by mass or less. In order to obtain coated particles having a uniform polymer layer, it is important to use particles having a water / n-hexane dispersibility tendency on the water side.

  On the other hand, when there is no hydrophilic group, or even if it has a hydrophobic group, the reason is that the hydrophobic group has a great influence. It is preferable to use particles having a water / n-hexane dispersibility tendency on the hexane side. In particular, when trying to adsorb a polymerizable monomer having a solubility in water of less than 1% by mass, such as styrene and perfluoroalkyl ester of (meth) acrylic acid, the water / n-hexane dispersibility tendency is on the hexane side. In addition, it is preferable to use particles having a modified hydrophobization degree of 40% by mass or more (particularly 50 to 90% by mass) as core particles.

  In addition, the water / n-hexane dispersibility is said to be obtained by adding substantially equal amounts of water and n-hexane to a glass test tube, etc., adding a small amount of particle powder thereto, and shaking well so that the particles are mixed with water and hexane. It can be judged by which side it is distributed. The modified hydrophobization degree is a methanol concentration at which the amount of suspension obtained by a method of measuring the suspension ratio of the particle powder with respect to a solution with a changed water-methanol ratio is 50%.

  The combination of the hydrophilic property and the hydrophobic property of the above-mentioned core particle and polymerizable monomer is merely an example of a particularly preferable combination, and does not indicate that it cannot be adsorbed unless the above conditions are satisfied. For example, even if the solubility in water is 5% by mass or more, a polymerizable monomer (such as 2-hydroxyethyl methacrylate) having a solubility in hexane of about 5% by mass or more has a water / n-hexane dispersibility tendency of hexane side, It can be adsorbed to the core particles on either water side.

  In general, inorganic particles such as inorganic oxide particles not subjected to any surface treatment have a water / n-hexane dispersibility tendency on the water side. The method for setting the dispersibility of such inorganic particles to the n-hexane side is not particularly limited, and a known surface treatment method may be employed. Specific examples include treatment with a silane coupling agent, a titanate coupling agent, silicone oil, cyclic siloxane, hexaalkyldisilazane, and the like. Among these, even when the amount of reactive groups such as silanol groups on the surface of the particle is small, it is uniformly processed, and since there are only one or two reaction ends, the treatment agent itself gels and fine particles are formed. An agglomerate generated by mixing or gelation does not adhere to the surface of the inorganic particles to form a non-uniform surface, and further, because it is highly reactive, it becomes an efficiently treated particle and is not immobilized. The treatment with cyclic siloxane or hexaalkyldisilazane is preferred in that the treatment agent is less likely to elute. Furthermore, in the case of particles treated with cyclic siloxane or hexaalkyldisilazane, the acid resistance and alkali resistance of the coated particles obtained by the production method of the present invention are higher than in the case of particles treated only with a silane coupling agent. Tend to be better.

  Among cyclic siloxanes, the following general formula is used because it is easy to obtain inorganic particles whose surface is uniformly coated due to large strain and easy cleavage.

(Wherein R ¹ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, a hydrogen atom or a hydroxyl group, Me is a methyl group, and n is an integer of 3 to 6)
It is preferable to treat with a cyclic siloxane represented by

In the above formula, R ¹ is a hydrocarbon group having 1 to 18 carbon atoms. The hydrocarbon group is not particularly limited as long as it has 1 to 18 carbon atoms, and may be any known group. Specific examples of the hydrocarbon group include straight chain or branched alkyl groups having 1 to 18 carbon atoms such as a methyl group, an ethyl group, a propyl group, a hexyl group, and an octadecyl group, a carbon such as a cyclopentyl group and a cyclohexyl group. A cyclic alkyl group having 4 to 6 carbon atoms; an alkenyl group having 2 to 18 carbon atoms such as vinyl group, allyl group, isopropenyl group, and octadecynyl group; phenyl group, naphthyl group, tolyl group, styryl group, xylyl group, mesityl group, etc. A substituted or unsubstituted aryl group having 6 to 18 carbon atoms; an aralkyl group having 7 to 9 carbon atoms such as a benzyl group and a phenethyl group;

  Among the hydrocarbon groups, a linear alkyl group having 1 to 3 carbon atoms, a phenyl group, a phenethyl group, or a vinyl group is particularly preferable. Moreover, in said formula, n is 3-6, Most preferably, it is 3-4.

  Specific examples of such cyclic siloxanes include octamethylcyclotetrasiloxane, hexamethylcyclotrisiloxane, tetramethyltetraphenylcyclotetrasiloxane, trimethyltriphenylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, trimethyltrivinyl. Examples thereof include cyclotrisiloxane, tetramethylcyclotetrasiloxane, and trimethylcyclotrisiloxane.

  In the case of treatment with hexaalkyldisilazane, the following general formula

(In the above formula, R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 18 carbon atoms.)
A hexaalkyldisilazane represented by In the above formula, examples of the alkyl group represented by R ^{2 to} R ⁷ include the same groups as those exemplified as R ¹ in the cyclic siloxane. In order to obtain high processing efficiency, the R ^{2 to} R ⁷ are preferably a linear alkyl group having 1 to 3 carbon atoms. R ^{2 to} R ⁷ may be different from each other, but are preferably the same group from the standpoint of availability and surface treatment efficiency.

  Specific examples of particularly preferred hexaalkyldisilazane include hexamethyldisilazane, hexaethyldisilazane, hexapropyldisilazane and the like.

  The cyclic siloxane and hexaalkyldisilazane may be used alone or in combination with two or more different compounds. Moreover, you may use together with another surface treating agent.

  The method of surface treating and hydrophobizing inorganic particles using the surface treating agent as described above is not particularly limited as long as it is in accordance with a known technique, but aggregation is unlikely to occur during the treatment. A method using a dry process that does not use a solvent is preferable because it does not require time and effort such as removal.

  For example, when the treatment with hexaalkyldisilazane is performed, it is preferable to employ the methods described in Japanese Patent No. 2886037 and Japanese Patent No. 2886105. In this method, powder of inorganic particles is introduced into a container, and the container is sealed so that the partial pressure of hexamethyldisilazane is about 25 to 150 kPa in an inert gas atmosphere at a temperature of about 200 to 300 ° C. And is maintained for a certain period of time, preferably about 0.5 to 2 hours. At this time, water vapor is present in the container at a partial pressure of about 30 to 100 kPa, and a basic gas such as ammonia is allowed to coexist at a partial pressure of about 10 to 100 kPa as necessary.

  In the case of treating with cyclic siloxane, a liquid or gaseous cyclic siloxane is added to the inorganic particle powder while stirring, and then heated in a sealed reaction system. To describe this method more specifically, first, while stirring particles with a high-speed stirring device such as a Henschel mixer in an inert gas atmosphere such as nitrogen or argon, a cyclic siloxane or the like is added in a gaseous or liquid state thereto, It can be produced by heating to a predetermined temperature in a sealed reaction system. The method of adding cyclic siloxane or the like to the particles may be either liquid or gaseous, and when added in liquid form, it may be added dropwise or by spraying. It is particularly preferable to add it in the form of a gas from the viewpoint that it can be uniformly processed. The heating temperature is not particularly limited as long as the particle surface can be hydrophobized by cyclic siloxane or the like, but in general, it is preferably not less than the boiling point of the cyclic siloxane to be used, and usually about 100 to 300 ° C. It is. Further, the stirring speed at the time of stirring is not particularly limited, and cannot be generally specified depending on the stirring device used, but is generally about 100 to 3000 rpm.

  By adopting such a dry treatment, it is possible to prevent agglomeration in the surface treatment step of inorganic particles, and if necessary, it is possible to coat with a polymer in the same reaction vessel, which is industrially advantageous. is there.

  In the production method of the present invention, a polymerizable monomer is adsorbed on the hydrophobic or hydrophilic particles as described above. The polymerizable monomer may be appropriately selected according to the target coated particles, and is not particularly limited, but is a radical polymerizable such as a (meth) acryl group or a styryl group in terms of excellent polymerizability. The polymerizable monomer having an unsaturated double bond (hereinafter referred to as vinyl monomer) is preferable.

  Specific examples of the vinyl monomer include the following.

  1. Vinyl monomers having no ion-dissociable hydrophilic group; styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, p-tert-butylstyrene, chloromethylstyrene, p-chlorostyrene, Monofunctional aromatic vinyl monomers such as vinyl naphthalene; aromatic vinyl monomers such as polyfunctional aromatic vinyl compounds such as divinylbenzene, divinylbiphenyl, trivinylbenzene, and divinylnaphthalene . Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tritridecyl (meth) acrylate, (meth) acrylic acid Benzyl, phenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxy (meth) acrylate Monofunctional non-fluorine (meth) acrylic monomers such as ethyl, diacetone methacrylamide, methacrylonitrile, methacrylolein and the like. Ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylol methanetri (meta ) Polyfunctional non-fluorinated (meth) acrylic monomers such as acrylate, tetramethylolmethanetetra (meth) acrylate, methylenebis (meth) acrylamide, hexamethylenedi (meth) acrylamide and the like. Perfluoroalkyl esters of (meth) acrylic acid such as trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, perfluorobutyl (meth) acrylate, perfluoro-2-ethylhexyl (meth) acrylate, and the like. Vinyl acetate, methyl vinyl ketone, vinyl pyrrolidone, ethyl vinyl ether, divinyl sulfone, diallyl phthalate, etc.

  2. Vinyl monomers having hydrophilic groups capable of ion dissociation; styrene sulfonic acid and its salts, vinyl naphthalene sulfonic acid and its salts, vinyl vinyl trimethylamine, vinyl benzyl triethyl amine, vinyl pyridine, vinyl imidazole, and other aromatic vinyl series Monomers. (Meth) acrylic having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, N-methylol (meth) acrylamide, etc. Series of monomers. (Meth) acrylic acid, maleic acid, 2- (meth) acryloyloxyethyl succinate and its salts, 2- (meth) acryloyloxyethyl maleate and its salts, 2- (meth) acryloyloxyethyl phthalate, etc. (Meth) acrylic monomers having a carboxyl group and salts thereof. (Meth) acrylic monomers having a phosphate group such as (meth) acryloxyethyl acid phosphate and salts thereof. (Meth) acrylic monomers having a sulfonic acid group such as 2- (meth) acrylamido-2-methylpropanesulfonic acid and 3-methacryloyloxypropanesulfonic acid, and salts thereof. (Meth) acrylic monomers having an amino group such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; (Meth) acrylic monomers having a quaternary ammonium base, such as (meth) acrylic acid dimethylaminoethyl methyl chloride salt and (meth) acrylic acid dimethylaminoethylbenzyl chloride salt. Vinyl monomers having a phosphonic acid group such as vinylphosphonic acid and salts thereof.

  In the production method of the present invention, these polymerizable monomers may be used alone or in combination of two or more depending on the intended polymer coating layer. For example, by using 0.05 to 100% by mass of a polyfunctional polymerizable monomer in the total polymerizable monomer, a cross-linked polymer unnecessary for the solvent can be obtained. When the polymerizable monomer as a main component is a solid at normal temperature and normal pressure, it is also preferable to dissolve in a liquid polymerizable monomer copolymerized with the polymerizable monomer.

  In particular, as a combination of polymerizable monomers, (1) a method using only a monofunctional aromatic vinyl monomer or a monofunctional (meth) acrylic monomer. As a result, a film made of a non-crosslinked polymer is produced.

  (2) Mainly monofunctional aromatic vinyl monomers that do not have hydrophilic groups, and polyfunctional monomers (preferably polyfunctional aromatic vinyl monomers) are fully polymerizable. The method of using the polymerizable monomer mixture mix | blended in the range of 0.05-40 mass parts (preferably 0.1-10 mass parts) with respect to 100 mass parts of monomers. Compared to the case of mainly using a (meth) acrylic monomer, a polymer coating layer that is excellent in chemical stability such as hydrolysis resistance and hardly peels off or decomposes even under more severe conditions can be obtained. In addition, the polymer obtained by this method has excellent chemical stability because it is easy to introduce an ion-dissociable group into an aromatic group by the method described later, and ion exchange Coated particles excellent in functionality such as properties can be obtained.

  (3) Mainly monofunctional (meth) acrylic monomers having a hydrophilic group and all polyfunctional monomers (preferably polyfunctional (meth) acrylic monomers) The method of using the polymerizable monomer mixture mix | blended in the range of 0.05-40 (preferably 0.1-10 mass parts) with respect to 100 mass parts of polymerizable monomers. For (meth) acrylic monomers, compounds having various functional groups are provided industrially at low cost, and it is easier to produce coated particles having a polymer coating layer having such functional groups. It is. This also makes it easy to control the chemical structure of the polymer layer, for example, it is easy to adjust a polymer coating layer having different functional groups in a specific ratio. Furthermore, it can be purified in a monomer state, and even if an undesired side reaction occurs when a functional group is introduced and impurities are mixed in, it can be easily removed by the purification.

  The polymerizable monomer (or a mixture thereof) is brought into contact with the core particles while stirring the powder of the core particles. The polymerizable monomer may be added alone to the silica-based particles whose surface has been hydrophobized, but in order to efficiently carry out the polymerization step described later, it is preferable to add the mixture in a state where a polymerization initiator is added.

  As a polymerization initiator to be used, a known polymerization initiator may be appropriately selected and used according to the polymerizable monomer to be used, and is not particularly limited. However, the polymerization initiator exhibits a polymerization initiation ability by heating. This is preferable because the operation is simpler. For example, when a vinyl monomer is used as the polymerizable monomer, octanoyl peroxide, lauroyl peroxide, t-butylperoxy-2-ethylhexanoate, benzoyl peroxide, t-butyl peroxide Organic peroxides such as oxyisobutyrate, t-butylperoxylaurate, t-hexylperoxybenzoate, di-t-butylperoxide, 2,2, -azobisisobutyronitrile and 2,2 An azobis-based polymerization initiator such as, -azobis- (2,4, -dimethylvaleronitrile) can be cited as a suitable polymerization initiator. These polymerization initiators are generally used in an amount of 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the polymerizable monomer.

  Moreover, you may use what mix | blended other additives, such as a polymerization inhibitor, a polymerization inhibitor, and an ultraviolet absorber, as needed. Further, when the polymerizable monomer is a solid, it can be made liquid by using a small amount of a solvent.

  A method of bringing such a polymerizable monomer and a mixture of optional components blended as necessary (hereinafter referred to as a polymerizable monomer mixture) with the core particles is not particularly limited, but preferably In addition, a method of adding a polymerizable monomer mixture in a gaseous or liquid state in an inert gas atmosphere such as nitrogen or argon, more preferably, spraying a liquid polymerizable monomer mixture in an inert atmosphere. How to add. A known spray nozzle or the like can be suitably used for spraying. The addition rate is not particularly limited and may be determined according to various other conditions, but is generally 1 to 20 ml / min per 100 g of core particles. The temperature conditions for adding these are not particularly limited, and may be under cooling or under heating. However, since the monomer is polymerized before coating at an excessively high temperature, generally about −10 to 40 ° C. is preferable. . The stirring conditions for the powder composed of the core particles are as described above.

The amount of the polymerizable monomer to be added is not particularly limited, and may be appropriately set depending on a desired coating thickness. The greater the amount used, the greater the coating amount (thickness of the coating), but if it is too large, it becomes a bulk polymer and the core particles are present in the polymer. A powder of coated particles, which is a product, cannot be obtained. Further, when the amount of the polymerizable monomer mixture used is too large, the particles tend to aggregate. In general, it is preferable that the average thickness of the coating layer is set to be 1/10 or less of the diameter of the core particle and 1000 nm or less. The amount of the polymerizable monomer used for the coating layer having such a thickness depends on the specific surface area and particle diameter of the core particles and cannot be generally stated, but in general, the specific surface area of the particles If 2 × 10 ⁻⁴ to 8 × 10 ⁻⁴ g of polymerizable monomer is used per 1 m ² , a coating layer having a thickness equivalent to about 1 nm is formed. It can be appropriately determined according to the specific surface area. A typical use amount of the polymerizable monomer is 0.001 to 0.4 g per 1 g of core particles.

  Moreover, when adding the above-mentioned solvent or other optional components, if the amount of the solvent used is too large, the particles are likely to aggregate. Therefore, even when all the polymerizable monomers, solvents, and other components to be added are added, it is preferable that the amount of the polymerizable monomer, the solvent, and the other components be within the range that does not form a paste or dispersion and maintains the powder state. In order to avoid agglomeration between particles, generally, the amount of polymerizable monomer, solvent and other components to be added is determined by the amount of oil absorption of the powder composed of core particles (polymerizable monomer, solvent and other components). 3/4 or less, more preferably 1/2, further preferably 1/3 or less, particularly preferably 1/5 or less, and most preferably 1/10 of that of the mixture).

  In this way, by adding the polymerizable monomer (and other optional components) to the stirred core particle, the polymerizable monomer (and other optional component) is adsorbed on the core particle. . In the production method of the present invention, the polymerizable monomer is then polymerized to form a polymer, and the powder is made of particles in a state where the core particles are covered with the polymer. In the present invention, this coating means not only the state of covering the outermost surface of the core particle, but also the case where the core particle has pores into which the polymerizable monomer can enter. The state which covered the wall surface, the state which exists so that this pore may be filled, or the state which combined them is also included. The reason is not clear, but from the measurement results of the pore volume before and after coating, etc., according to the production method of the present invention, the polymerizable monomer has a diameter larger than that of pores of 20 nm or less of the core particles. It seems to preferentially adsorb in small pores and then adsorb so as to cover the entire particle. That is, when the core particle has pores of 20 nm or less, the polymerizable monomer is first adsorbed mainly so as to fill the inside of the pore, and then the whole core particle is increased when the amount of the polymerizable monomer increases. Adsorb so as to cover. Therefore, when the amount of the polymerizable monomer used is small, a powder consisting of particles in which the polymer is mainly present in the pores can be obtained, while the amount of the polymerizable monomer used is sufficiently large. As a result, composite particles in which the particles are cores and the outer surfaces of the particles made of a polymer are covered with the polymer are obtained.

  As a method of polymerizing the polymerizable monomer thus adsorbed, a known method may be adopted as a polymerization method of the polymerizable monomer used, and it is not particularly limited. Is a method of initiating polymerization by heating. When the polymerizable monomer used is a vinyl monomer, it can be more efficiently polymerized by using a thermal polymerization initiator as described above. Moreover, the said heating temperature should just set suitably well-known conditions with the kind etc. of the polymerizable monomer and polymerization initiator which were used, and is generally 40-230 degreeC, Preferably it is about 50-180 degreeC.

  Further, when the polymerizable monomer used is a vinyl monomer, these operations are preferably performed in an inert gas atmosphere such as nitrogen or argon in order to prevent polymerization inhibition by oxygen.

  The pressure in the reaction vessel is not particularly limited, and may be pressurized, normal pressure, or reduced pressure. Depending on the type of polymerizable monomer used, pressurization is preferred among them. The pressure for pressurization is generally about 0.01 to 0.6 MPa. The polymerization time may be appropriately set according to the other conditions as described above, and is generally about 30 to 180 minutes.

  Since the production method of the present invention is a dry method as described above, the obtained coated particles may be taken out of the reaction vessel as they are, and the coated particles obtained as in the wet method using a solvent need to be separated from the solvent and dried. Absent.

  The coated particles thus obtained have various physical properties depending on the type of polymerizable monomer used. For example, when (meth) acrylic acid perfluoroester is used as the main component, coated particles having extremely excellent water repellency can be obtained. In addition, when a polymerizable monomer having a carboxyl group, a sulfonic acid group, an amino group, an ammonium group or the like is used, it has acid / basicity derived from these functional groups, ion exchange properties, antibacterial properties, etc. It can be a coated particle.

  On the other hand, when a polymerizable monomer having no such functional group is used, the above functional group can be introduced as necessary. A typical example of functionalization by introducing such a functional group is introduction of an ion dissociable group as described above. By introducing such an ion dissociable group, acid / basicity, ion exchange property, antibacterial property and the like are expressed as described above.

  As the ion dissociable group to be introduced, any known ion dissociable group may be appropriately selected according to the purpose. Specifically, as the group capable of dissociating a cation, a sulfonic acid group or a carboxylic acid group may be used. Groups, phosphonic acid groups, phosphoric acid groups, phenolic hydroxyl groups, thiol groups, perfluoro tertiary alcoholic hydroxyl groups, arsenic acid groups, selenic acid groups, and salts thereof. Quaternary or tertiary ammonium bases, tertiary amine groups, pyridinium bases, imidazolium bases and the like. Among these, sulfonic acid groups or salts thereof, quaternary or quaternary are preferred because they are highly useful and easy to manufacture such as introduction of an aromatic vinyl monomer into a polymer. A tertiary ammonium base is particularly preferred.

  The ion-dissociable group can be introduced in accordance with, for example, the ion-exchange group introduction method in the ion-exchange resin production method.

  For example, when a polymerizable monomer such as styrene is used and the polymer has an aromatic hydrocarbon ring such as a benzene ring in its structure, it is known to react with fuming sulfuric acid, chlorosulfonic acid, sulfur trioxide, etc. Sulfonation or the like may be performed by a method. In the case of a polymer having an acid ester structure such as a methyl methacrylate polymer, an acid group can be introduced by hydrolysis of the ester. When the polymer has an amino group, it can be reacted with an alkyl halide, or when it has a halogenated alkyl group, it can be reacted with an amine compound to introduce an ammonium group. Furthermore, when it has an epoxy group, it can be sulfonated by using sulfanilic acid, sodium sulfite, etc. to introduce a sulfonic acid group, or it can be reacted with an amine compound to introduce an ammonium base. it can.

  In addition, other known chemical reactions can be applied to introduce various ion-exchange groups, and functional groups other than ion-exchange groups may be introduced. When introducing these functional groups, it is necessary to select the introduction form and reaction conditions as appropriate so that the covering polymer is not lost due to peeling or the like. In general, a polymer of an aromatic vinyl monomer is chemically more stable than a (meth) acrylate monomer having an ester structure, and various functional groups can be easily introduced.

  In introducing such a functional group, a method of appropriately setting reaction conditions such as temperature and pressure without using a solvent and contacting the reactive agent in gaseous form with the coated particles in order to prevent aggregation of the resulting particles. Is preferably adopted. For example, in the introduction of the ion-exchange group, when a sulfonic acid group is introduced, a method of contacting with a sulfur trioxide gas can be suitably employed. Similarly, when introducing an ammonium base, it is preferable to select conditions such as reaction temperature and pressure so that the amine compound or alkyl halide to be used is in gaseous form and in contact with the coated particles.

  Depending on the application, polymers that are mainly composed of aromatic vinyl monomers have higher chemical stability than polymers that are mainly composed of (meth) acrylate monomers. This is preferable. In general, in the case of a polymer having an ion dissociable group, a crosslinked polymer is more preferable from the viewpoint of obtaining high water resistance.

  The coated particles having an ion dissociable group obtained by such a production method have ion exchange properties. That is, the ion dissociable group acts as an ion exchange group. The amount of the ion exchange group is not particularly limited, and may be set as appropriate according to its use and purpose, but is generally 0.005 to 4 meq / g-coated particle, preferably 0.1. ~ 3 meq / g-coated particles.

  According to the production method of the present invention, it has at least one group selected from the group consisting of a sulfonic acid group, a sulfonic acid group, and an ammonium base, which could not be produced by application of a conventionally known wet method. Novel coated particles in which a polymer is coated with inorganic particles are provided. That is, a polymerizable monomer having a group (strongly hydrophilic group) that is almost completely ionically dissociated in an aqueous solution such as a sulfonic acid group, a sulfonic acid group, or an ammonium base is usually solid, and the influence of the group. Because of its strong hydrophilicity, it is hardly soluble in organic solvents. Accordingly, when inorganic particles (nuclear particles) are dispersed in a solvent and the polymerizable monomer is adsorbed thereto, an aqueous solvent is required as the solvent. However, if such a polymerizable monomer having a strongly hydrophilic group is dissolved in an aqueous solvent, the polymerizable monomer is more stable when dissolved in the solvent. It does not adsorb, and thus coated particles cannot be obtained. Furthermore, when a cross-linkable polymer is obtained using a polyfunctional polymerizable monomer that serves as a cross-linking agent, the polyfunctional polymerizable monomer is generally highly oleophilic, In many cases, the solubility tendency with respect to is different from that of a polymerizable monomer having a strongly hydrophilic group.

  According to the production method of the present invention, since it is not necessary to disperse the particles in a solvent, the polymerizable monomer having a strongly hydrophilic group can be adsorbed to the inorganic particles without causing the above-mentioned problems. Thus, it is possible to produce coated particles coated with a polymer having the group. In particular, a cross-linked polymer using a crosslinking agent in an amount of 1 to 50% by mass or more, preferably 3 to 30% by mass in all polymerizable monomers has good durability against various solvents. Very useful. The coated inorganic particles having a strongly hydrophilic group of 0.005 to 4 meq / g-coated particles, preferably 0.1 to 3 meq / g-coated particles, having the above-described ion exchange capacity, are inorganic cores. An excellent particle having both the mechanical strength of the particle and the physical properties of the polymer layer having ion exchange properties of the coating layer, and also has excellent solvent resistance. For example, a packing material for ion exchange chromatography It is highly useful as a solid phase catalyst for various acid or base catalytic reactions, an antibacterial filler for various resin products, and the like.

  In addition, the coated particles obtained by the production method of the present invention are not limited to those having a strongly hydrophilic group, and can be used for various applications depending on the type of polymer that the particles have. For example, packing materials for chromatography such as high performance liquid chromatography and gas chromatography; spacers for liquid crystals; coating materials for coating liquids or paints for metals, ceramics or resins; natural rubber, styrene-butadiene rubber, silicone rubber, fluorine Rubber and other rubber fillers; resin molded product fillers; various functional fillers such as dental material fillers; cosmetics, pharmaceuticals, toners, paper quality modifiers, adsorbents, water treatments, It can be used for purification of food, etc., catalyst, bio and chemical processes.

  As can be understood from the above application examples, the production method of the present invention is carried out dry, and a powder is obtained. However, the powder (coating particles constituting the powder) is then required. Accordingly, there is no problem in using it by dispersing in various solvents.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited to these.

  1. Abbreviations and abbreviations: Abbreviations and abbreviations of compounds used in Examples and Comparative Examples are as follows.

2. Water / n-hexane distribution tendency 3 g each of water and n-hexane were placed in a 10 ml clear glass sample bottle. 0.6 g of the particle powder to be evaluated was put therein and shaken vigorously by hand. Then, after waiting to isolate | separate into an aqueous phase and n-hexane phase, the cloudiness state of the liquid was evaluated visually. When the aqueous phase (lower layer) was cloudy, the distribution tendency was on the water side, and when the hexane phase (upper layer) was cloudy, the distribution tendency was on the hexane side.

3. Modified hydrophobization degree In a sample glass bottle with a capacity of 110 ml, put 0.5 g of the particle powder and 100 ml of methanol / water mixture, stir for 30 minutes using a shaker, let stand overnight, and then settle the sediment and liquid part. Aspiration was left behind. It dried at 120 degreeC for 6 hours, and measured the weight of the floating part. The amount of floating was examined by changing the methanol / water ratio, and the methanol concentration where 50% of the surface-coated silica was floating was determined.

4). Average particle size A (average primary particle size)
For particles photographed with a scanning electron microscope (SEM) or transmission electron microscope (TEM), each image is analyzed with high-definition image analysis software IP-1000PC (Asahi Engineering Co., Ltd.) using 1000 or more and less than 2000 images. Then, assuming that the shape of the particles is spherical, the average particle diameter of the primary particles was obtained.

5). Average particle size B
While dispersing the particle powder in ethanol and applying ultrasonic waves, the particle size distribution is measured by a light scattering diffraction type particle size distribution analyzer (Beckman Coulter, Inc .: Coulter LS230), and the value of the number-based arithmetic average diameter D ₅₀ is averaged. The particle diameter was set to B.

6). Specific surface area Using a specific surface area measuring apparatus (manufactured by Shimadzu Corporation: Flowsorb 2-2300 type), nitrogen gas was used as an adsorbed gas, and the BET method was used.

7). Carbon Amount The amount of carbon coating the particles was measured by heating the particle powder to 1350 ° C. in an oxygen atmosphere using a trace carbon analyzer (EMIA-511 type manufactured by Horiba Seisakusho). The amount of carbon obtained by this measurement was converted to 1 g of coated particles. In addition, as a pretreatment for the coating amount measurement, the particles powder is heated at 80 ° C., and the system is depressurized to remove monomers not involved in the surface coating and moisture adsorbed in the air. After that, the carbon content of the particle powder was determined.

8). Cation exchange capacity measurement Particle powder was dispersed in 1 mol / l HCl aqueous solution and stirred for 10 hours or more to form a hydrogen ion type, then filtered and washed with water, and the residue was dissolved in 1 mol / l NaCl aqueous solution. The mixture was stirred for more than an hour to replace the sodium ion type. Subsequently, the liberated hydrogen ions contained in the solution obtained by filtration were quantified with a potentiometric titrator (COMTITE-900, manufactured by Hiranuma Sangyo Co., Ltd.) (A: mol).

Subsequently, the particles are dispersed in a 1 mol / l HCl aqueous solution, stirred for 4 hours or more, and the residue obtained by filtration is thoroughly washed with ion-exchanged water, dried at 60 ° C. for 5 hours, and its weight is measured. (W _C : g). Based on the above measurements, the following equation cation exchange capacity * cation exchange capacity _{= A × 1000 / W C [} mmol / g- dry weight]
Determined by

9. Anion exchange capacity measurement Particle powder was dispersed in 1 mol / l HCl aqueous solution and stirred for 10 hours or more to make a chlorine ion type, then filtered and washed, and the residue was dissolved in 1 mol / l NaNO ₃ aqueous solution. The mixture was stirred for 10 hours or more and replaced with the nitrate ion type. Subsequently, free chlorine ions contained in the solution obtained by filtration were quantified with a potentiometric titrator (COMTITE-900, manufactured by Hiranuma Sangyo Co., Ltd.) (B: mol).

Subsequently, the above particles are dispersed in a 1 mol / l NaCl aqueous solution, stirred for 4 hours or more, the residue obtained by filtration is sufficiently washed with ion-exchanged water, dried at 60 ° C. for 5 hours, and its weight is measured. (W _a : g). Based on the measured value, the anion exchange capacity is expressed by the following formula * anion exchange capacity = B × 1000 / W _a [mmol / g-dry weight]
Determined by

10. Pore Volume The pore distribution and pore volume of the particle powder were measured by a mercury intrusion method using a pore distribution measuring device (PoreMaster-60, manufactured by QUANTACHROME). The pore volume was calculated for pores having a pore diameter of 7-15 nm.

11. Acid / Alkaline Resistance Test The acid or alkali durability test was conducted by putting 10 g of surface-coated silica particles in a 500 ml flask, adding 1 ml / l HCl aqueous solution or 300 ml of 1 mol / l NaOH aqueous solution to 50 ° C. For 48 hours. Subsequently, this was filtered, washed with water, sufficiently dried, and the coating stability, that is, acid resistance or alkali resistance was evaluated from the amount of carbon by carbon analysis. Moreover, SEM or TEM observation was performed about the particle | grains which performed these tests, and it was confirmed whether the shape of a particle had changed.

12 Oil absorption amount The polymerizable monomer solution was added little by little to 10 g of the particle powder, the state was observed while kneading, and the amount added from the disperse dispersed state to one lump was determined. In addition, the amount (g) of the polymerizable monomer solution was calculated per 1 g of particle powder.

Production Example 1
Surface treatment is carried out with a specific surface area of 200 m ² / g produced by a pyrolysis method, an average particle diameter A (average primary particle diameter) of 0.016 μm, and an average particle diameter B (average secondary particle diameter) of 0.07 μm. 50 g of silica powder (manufactured by Tokuyama Co., Ltd., trade name QS102; hereinafter referred to as QS102) was charged into a stainless steel autoclave having an internal volume of 1000 ml. After the inside of the autoclave was replaced with nitrogen gas, 20 g of D4 was atomized with a two-fluid nozzle while the stirring blade attached to the autoclave was rotated at 400 rpm and sprayed uniformly onto the silica powder. After stirring for 30 minutes with nitrogen gas flowing, the autoclave was sealed and heated at 275 ° C. for 1 hour. Subsequently, the system was depressurized while being heated to remove unreacted D4. Table 2 shows the physical properties of the obtained particle powder (hereinafter referred to as QS102-D4).

Production Example 2
50 g of QS102 was charged into a stainless steel autoclave having an internal volume of 1000 ml. After the inside of the autoclave was replaced with nitrogen gas, the stirring blade attached to the autoclave was rotated at 400 rpm, 20 g of P4 was atomized with a two-fluid nozzle, and sprayed uniformly onto the silica powder. After stirring for 30 minutes, the autoclave cock was closed and sealed, and heated at 400 ° C. for 1 hour. Subsequently, the pressure was reduced while heating to remove unreacted P4. Table 2 shows the physical properties of the obtained particle powder (hereinafter referred to as QS102-P4).

Production Example 3
The surface of QS102 was treated with HMDS according to the method described in Japanese Patent No. 2886037. That is, 50 g of QS102 was charged into a stainless steel autoclave having an internal volume of 1000 ml. After the inside of the autoclave was replaced with nitrogen gas, the stirring blade attached to the autoclave was rotated at 800 rpm, dimethyldichlorosilane 0.2 g / min, water vapor 1.8 g / min and heated to 450 ° C. It was insufflated with nitrogen for 40 minutes. After the treatment, unreacted substances and by-products were purged with nitrogen and dried. Next, after replacing with nitrogen atmosphere again, at a reaction temperature of 200 ° C., hexamethyldisilazane was supplied at 2 g / min and water vapor at 0.11 g / min for 75 minutes to perform a hydrophobic treatment. After the reaction, deammonia was carried out by supplying nitrogen at 40 L / min for 30 minutes. Table 2 shows the physical properties of the obtained particle powder (hereinafter referred to as QS102-HMDS).

Production Example 4
50 g of QS102 was put in a juicer mixer, and while stirring so as to be in a floating state, 11 g of methyltrimethoxysilane (manufactured by Shin-Etsu Chemical) was atomized with a two-fluid nozzle and sprayed onto silica powder to uniformly wet the surface. Thereafter, the surface-treated powder was transferred to a 1-liter separable flask and heated at 100 ° C. for 2 hours under a nitrogen stream to obtain silica powder whose surface was treated with the alkoxysilane compound. Table 2 shows the physical properties of the obtained particle powder (hereinafter referred to as QS102-TMS).

Production Example 5
Silica powder produced by a sedimentation method with a specific surface area of 290 m ² / g, an average particle size A of 3.7 μm, an average particle size B of 5.4 μm and not subjected to surface treatment (trade name X37B, manufactured by Tokuyama Corporation; A powder of cyclic siloxane-treated silica particles was obtained in the same manner as in Production Example 1 except that X37B was used. Table 2 shows the physical properties of the obtained particle powder (hereinafter referred to as X37B-D4).

Production Example 6
Silica powder produced by the sol-gel method with a specific surface area of 1 m ² / g and an average particle size B of 4.3 μm and not subjected to surface treatment (trade name LS-H043, manufactured by Tokuyama Corporation; hereinafter referred to as H043) ) Was processed with HMDS. That is, 50 g of H043 was charged into a polytetrafluoroethylene inner cylinder type stainless steel autoclave having an inner volume of 100 ml. After the inside of the autoclave was replaced with nitrogen gas, 10 g of HMDS and 1.5 g of water were atomized with a two-fluid nozzle while spraying the silica powder uniformly while rotating the stirring blade attached to the autoclave at 400 rpm. After stirring for 30 minutes, the autoclave was sealed and heated at 200 ° C. for 2 hours. Subsequently, the inside of the system was depressurized while being heated for deammonia. Table 2 shows the physical properties of the obtained particle powder (hereinafter referred to as H043-HMDS).

Production Example 7
Silica powder produced by a thermal melting method with a specific surface area of 2.2 m ² / g, an average particle diameter of 6.1 μm and not subjected to surface treatment (trade name Excelica SE-5 manufactured by Tokuyama Corporation; hereinafter referred to as SE5 50 g) was charged into a stainless steel autoclave having an internal volume of 500 ml. After the inside of the autoclave was replaced with nitrogen gas, the stirring blade attached to the autoclave was rotated at 800 rpm, 20 g of cyclic siloxane D4 was atomized with a two-fluid nozzle, and sprayed onto the silica powder. After stirring for 30 minutes, the autoclave cock was closed and sealed, and heated at 275 ° C. for 1 hour. Subsequently, the pressure was reduced with heating to remove unreacted cyclic siloxane. Table 2 shows the physical properties of the obtained particle powder (hereinafter referred to as SE5-D4).

  Various raw material particles (powder) used in Production Examples 1 to 7, obtained particles (powder), and commercially available silica powder (trade name Excelica SH03 manufactured by Tokuyama Co., Ltd .; hereinafter referred to as SH03) The physical properties are shown in Table 2.

Example 1
50 g of QS102-D4 was charged into a stainless steel autoclave having an internal volume of 1000 ml. After the inside of the autoclave was replaced with nitrogen gas, the stirring blade attached to the autoclave was rotated at 800 rpm to polymerize 8 g of chloromethylstyrene, 1 g of divinylbenzene, and 0.5 g of t-butylperoxy-2-ethylhexanoate. The monomer mixed solution was atomized with a two-fluid nozzle for about 15 seconds and sprayed onto silica powder to wet the surface. After stirring for 30 minutes, the autoclave cock was closed and sealed, the temperature was raised from 20 ° C. to 80 ° C. over 1 hour, and the temperature was maintained for 1 hour to polymerize the monomer. Table 3 shows the physical properties of the obtained powder. Moreover, the particle size distribution pattern after a process is shown in FIG. 1 with the thing of the particle | grains (QS102-D4) before a process. The oil absorption of QS102-D4 with respect to the polymerizable monomer mixed solution was 3.3 g / g-nuclear particles.

Example 2
The same processing operation as in Example 1 was performed except that QS102-P4 was used instead of QS102-D4. Table 3 shows various physical properties of the obtained powder.

Example 3
The same processing operation as in Example 1 was performed except that QS102-HMDS was used instead of QS102-D4. Table 3 shows various physical properties of the obtained powder. The oil absorption of QS102-HMDS with respect to the polymerizable monomer mixed solution was 3.1 g / g-core particles.

Example 4
The same processing operation as in Example 1 was performed except that QS102-TMS was used instead of QS102-D4. Table 3 shows various physical properties of the obtained powder.

Example 5
The same procedure as in Example 1 except that the amount of the polymerizable monomer mixed solution was reduced to 4 g of chloromethylstyrene, 0.5 g of divinylbenzene, and 0.3 g of t-butylperoxy-2-ethylhexanoate. Went. Table 3 shows various physical properties of the obtained powder.

Example 6
The same treatment operation as in Example 1 was performed except that the holding time at 80 ° C. for monomer polymerization was 150 minutes. Table 3 shows the physical properties of the obtained powder.

Example 7
The same procedure as in Example 1 was performed except that the polymerizable monomer mixed solution was replaced with a mixed solution of 5 g of styrene, 0.6 g of divinylbenzene, and 0.3 g of t-butylperoxy-2-ethylhexanoate. It was. Table 3 shows various physical properties of the obtained powder. The oil absorption of QS102-D4 with respect to the polymerizable monomer mixed solution was 3.8 g / g-core particles.

Example 8
The same treatment as in Example 1 except that the polymerizable monomer mixed solution was replaced with a mixed solution of 5.5 g vinylpyridine, 0.6 g divinylbenzene, and 0.3 g t-butylperoxy-2-ethylhexanoate. The operation was performed. Table 3 shows various physical properties of the obtained powder.

Example 9
Example 3 except that the polymerizable monomer mixed solution was replaced with a mixed solution of 6.7 g perfluorooctyl methacrylate, 0.2 g divinylbenzene, and 0.2 g t-butylperoxy-2-ethylhexanoate. The processing operation was performed. Table 3 shows various physical properties of the obtained powder. The oil absorption of QS102-D4 with respect to the polymerizable monomer mixed solution was 5 g / g-core particles.

Example 10
50 g of the coated particles produced in Example 1 are placed in a pressure-resistant glass container, and trimethylamine gas is introduced into the pressure-resistant glass container so that the trimethylamine gas concentration in the system is 90% or more, and nitrogen gas is further introduced into the system to obtain 0.3 MPa. The mixture was heated to 80 ° C. for 1 hour with stirring in a sealed state, and quaternary ammonium was formed. Subsequently, the system was evacuated to completely remove unreacted trimethylamine gas and collect the powder.

Examples 11-15
The same processing operation as in Example 10 was performed except that the coated particles were changed to the particles produced in each Example shown in Table 4.

Example 16
50 g of the coated particles produced in Example 7 were transferred to a pressure-resistant polytetrafluoroethylene container, solid sulfur trioxide was placed in a flask directly connected thereto, and the vaporized sulfur trioxide was filled with crosslinkable resin-coated silica with nitrogen gas. 15 minutes, and the sulfur trioxide gas concentration in the system is set to 30 vol% or more. Further, nitrogen gas is introduced into the system, pressurized to about 0.3 MPa, and stirred at 80 ° C. in a sealed state. And sulfonated by heating for 1 hour. Subsequently, the system was evacuated to completely remove the unreacted sulfur trioxide gas and recover the powder.

  Table 4 shows the results of evaluating the specific surface area, ion exchange capacity, and ion exchange group density of the particle powders obtained in Examples 9 to 16 and Examples 8 and 9.

Comparative Example 1
The operation was performed in the same manner as in Example 1 except that the stirring was not performed. After the processing operation was completed, the container was taken out from the container, but a fragile bulk body was generated in a portion close to the spray nozzle.

Comparative Example 2
50 g of the particle powder produced by the same method as in Example 1 was charged into a separable flask having an internal volume of 3000 ml, and a solution obtained by dissolving 120 g of polyvinylpyrrolidone as a dispersion stabilizer in a mixed solution of 800 ml of methanol and 1500 ml of ethylene glycol was used. The treated silica was added and stirred. To this dispersion, 10 g of 2-2azobisisobutylnitrile, 45 g of chloromethylstyrene and 56 g of divinylbenzene were added, and polymerization was carried out while heating at 60 ° C. for 8 hours. Subsequently, the supernatant of the dispersion was removed by decantation, and the silica particles were collected by filtration, and methanol was repeatedly poured onto the filter paper and washed. The collected powder was dried by a vacuum dryer at 80 ° C. to obtain a particle powder coated with a polymer. This was then treated in the same manner as in Example 9. The physical properties are shown in Table 4.

Example 17
Coating with a polymer was carried out in the same manner as in Example 1 except that X37B-D4 was used instead of QS102-D4. Table 5 shows the physical properties of the obtained particle powder.

Examples 18-19
Polymer coating was performed in the same manner as in Example 17 except that the amount of the polymerizable monomer mixing solution used was changed. Table 5 shows the amount of the polymerizable monomer solution and the physical properties of the obtained particle powder. The pore distribution is shown in FIG. 2 together with the results of the core particles (X37B-D4) and the particles obtained in Example 17, and the particle size distribution pattern is shown in FIG.

Examples 20-22
The particles produced in Examples 17 to 19 were subjected to quaternary ammonium formation by contacting with trimethylamine by the same treatment operation as in Example 10. Table 6 shows the physical properties of the obtained particles.

Example 23
Except that the temperature at the time of polymerization was changed to 160 ° C., the same treatment operation as in Example 17 was performed to obtain polymer-coated particles. Subsequently, a quaternary ammonium group was introduced by contact with trimethylamine by the same treatment operation as in Example 10. Table 6 shows the physical properties of the obtained particles.

Example 24
Example 1 using H043-HMDS in place of QS102-D4 and using 1.25 g of styrene and 0.2 g of t-butylperoxy-2-ethylhexanoate as the polymerizable monomer mixing liquid The same operation as described above was performed to coat with a non-crosslinked polymer. The specific surface area of the obtained particle powder was 1 m ² / g, the average particle diameter B was 4.3 μm, and the carbon content was 0.0003 g / g-coated particles. The SEM photograph before coating is shown in FIG. 4, and the SEM photograph after coating is shown in FIG.

Example 25
SE5-D4 was used in place of QS102-D4, and 1.3 g of styrene, 0.14 g of divinylbenzene, and 0.07 g of t-butylperoxy-2-ethylhexanoate were used as a polymerizable monomer mixing solution. A polymer was coated in the same manner as in Example 1 except that it was used. The average particle diameter 1 of the obtained coated particle powder was 6.163 μm, and the carbon content was 0.0004 g / g-coated particles. Subsequently, using this coated particle, the same operation as in Example 16 was performed to introduce a sulfonic acid group. The amount of carbon of the obtained particle powder is 0.0004 g / g-coated particles, the specific surface area is 1 m ² / g, the cation exchange capacity is 0.003 mmol / g, and the ion exchange group density is 3.0 × 10 ⁻³ mmol. / M ² .

Examples 26-30
The acid resistance and alkali resistance of the coated particle powders obtained in Examples 10, 11, 13, 15 and 25 were evaluated. The results are shown in Table 7.

Comparative Example 3
A solution in which 23 g of trimethoxysilyl-2- (p, m-chloromethyl) phenylethane (manufactured by United Chemical Technologies) is dissolved in 5 g of hexane while stirring so that 50 g of QS102 is in a suspended state. Was atomized with a two-fluid nozzle and sprayed onto silica powder to wet the surface. Then, it moved to the 1 liter separable flask, and it heated at 100 degreeC under nitrogen stream for 2 hours, and obtained the powder by which the surface was processed with the said alkoxysilane compound. Subsequently, this was contacted with trimethylamine by the same treatment operation as in Example 10 to perform quaternary ammonium formation. The amount of carbon of the obtained particle powder was 0.061 g / g-coated particles, and the anion exchange capacity was 0.38 mmol / g. Table 7 shows the evaluation results of acid resistance and alkali resistance.

Comparative Example 4
50 g of QS102 is put in a juicer mixer, and while stirring so as to be in a floating state, a solution in which 20 g of phenethyltrimethoxysilane (manufactured by Amax) is dissolved in 5 g of hexane is atomized with a two-fluid nozzle and sprayed onto silica powder. Wet the surface. Then, it moved to the 1 liter separable flask, and heated at 100 degreeC under nitrogen stream for 2 hours, and obtained the silica powder by which the surface was processed with the said alkoxysilane compound. Subsequently, this was contacted with sulfur trioxide by the same treatment operation as in Example 16 for sulfonation. The obtained particle powder had a carbon content of 0.051 g / g-coated particles and a cation exchange capacity of 0.11 mmol / g. Table 7 shows the evaluation results of acid resistance and alkali resistance.

Example 31
50 g of X37B was charged into a glass separable flask having an internal volume of 2000 ml. After replacing the inside with nitrogen gas, 6 g of dimethylaminoethyl methacrylate methyl chloride salt, 0.6 g of ethylene glycol dimethacrylate, 1.5 g of water, 2.6 g of 2-hydroxy, while rotating the stirring blade at 800 rpm A polymerizable monomer mixed solution consisting of ethyl methacrylate and 0.2 g of t-butylperoxy-2-ethylhexanoate was sprayed in the form of a mist with a two-fluid nozzle for about 15 seconds. After stirring for 30 minutes, the temperature was raised from 20 ° C. to 90 ° C. over 1 hour, and kept at the same temperature for 1 hour to polymerize the monomer. Table 8 shows the physical properties of the obtained powder. The oil absorption amount of X37B with respect to the polymerizable monomer mixed solution was 2.94 g / g-core particles.

Example 32
The same treatment operation as in Example 31 was performed except that the amount of the polymerizable monomer mixed solution used was doubled. Table 8 shows the physical properties of the obtained powder.

Example 33
The same treatment operation as in Example 31 was performed except that the amount of the polymerizable monomer mixed solution used was halved. Table 8 shows the physical properties of the obtained powder.

Example 34
9.6 g of dimethylaminoethyl methacrylate methyl chloride salt, 1.2 g of ethylene glycol dimethacrylate, 2.4 g of water, 5.2 g of 2-hydroxyethyl methacrylate and 0.5 g of t A treatment operation was performed in the same manner as in Example 31 except that the solution was changed to a solution composed of -butylperoxy-2-ethylhexanoate and the holding temperature at the time of polymerization was 80 ° C. This was then immersed in hot water at 100 ° C., and the ion exchange capacity was measured on the 1st to 14th days. Various physical properties immediately after preparation and ion exchange capacity after immersion in hot water are shown in Table 9 and FIG.

Example 35
The same treatment operation as in Example 34 was performed except that ethylene glycol dimethacrylate was not added to the polymerizable monomer mixed solution so that the polymer was non-crosslinked. Various physical properties immediately after preparation and ion exchange capacity after immersion in hot water are shown in Table 9 and FIG.

Comparative Example 5
The filler was taken out from the anion exchange type high performance liquid chromatography in which silica was treated with a silane coupling agent, and the ion exchange capacity immediately after preparation and after immersion in hot water was measured using the filler. The results are shown in Table 9 and FIG.

Examples 36-42
The same processing operation as in Example 31 was performed except that the combination of the core particle and the polymerizable monomer mixed solution was changed as shown in Table 10. Table 10 shows the physical properties of the obtained powder. The oil absorption amount in each combination of the core particles and the polymerizable monomer solution was 2.75 g in Example 36, 2.75 g in Example 37, 3.1 g in Example 38, and 3.75 in Example 39. 3 g, Example 41 was 0.20 g, and Example 42 was 0.35 g.

The figure which shows the particle size distribution pattern before and behind the process of the particle | grains which performed the coating process in Example 1. FIG. Pore distribution of particles obtained by coating the particles (X37B-D4) obtained in Production Example 5 and the particles obtained in Examples 17 to 19 using the particles as core particles and changing the amount of the polymerizable monomer. FIG. The particle size distribution of the particles obtained by carrying out coating by changing the amount of the polymerizable monomer using the particles (X37B-D4) obtained in Production Example 5 and the particles in Examples 17 to 19 as core particles. FIG. A scanning electron micrograph of particles (H043-D4) obtained in Production Example 7. The operation type | mold electron micrograph of the particle | grains obtained in Example 25. FIG. The graph which shows stability of the ion exchange capacity of the particle | grains manufactured in Examples 34 and 35 and the comparative example 5. FIG.

Claims (4)

  Contacting inorganic particle powder with a polymerizable monomer having a radical polymerizable unsaturated double bond under stirring, and adsorbing the polymerizable monomer to particles constituting the powder; and A method for producing polymer-coated particle powder, comprising a step of polymerizing the adsorbed polymerizable monomer.   2. The production method according to claim 1, wherein the particles constituting the powder are subjected to a surface treatment with a cyclic siloxane and / or a hexaalkyldisilazane prior to bringing the powder into contact with the polymerizable monomer.   The production method according to claim 1 or 2, wherein the polymer in the polymer-coated particle powder is a polymer having a hydrophilic functional group.   A polymer of a polymerizable monomer having a radical polymerizable unsaturated double bond is coated on at least a part of the surface of the inorganic particles surface-treated with cyclic siloxane and / or hexaalkyldisilazane. Polymer-coated inorganic particles characterized by

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