JPWO2017026425A1 - Silica gel porous particles and method for producing the same - Google Patents

Abstract

Provided is a silica gel porous particle having a through-hole, having a uniform shape, and the through-hole is not blocked.
A substantially spherical porous particle, wherein the porous particle has a through-hole formed therein by silica gel and communicated with a porous structure, and an end portion of the through-hole has the porous Porous particles characterized by opening toward the outside of the conductive particles.

Description

  The present invention relates to silica gel porous particles and a method for producing the same.

  A porous body having a through hole with which a porous structure communicates is used in various applications. Such porous bodies include those made of an organic polymer (Patent Document 1, etc.) and those made of silica gel (Patent Documents 2-3). In recent years, particulate porous bodies have been proposed. For example, a method of pulverizing a produced porous body to form particles (Patent Document 2) and a method of producing a particulate porous body from the beginning ( Patent Document 3).

JP2013-020960A JP 2014-148456 A Japanese Patent Laying-Open No. 2015-3860

  A porous body having a through-hole in which a porous structure communicates has an advantage that it is easier to handle than a massive porous body in applications such as a packing for a separation column for chromatography and a column reactor. However, the method of pulverizing the produced porous body to form particles has a problem that the produced porous particles are indefinite and have a low filling rate. Further, in the method for producing a particulate porous body from the beginning, there is a risk that a skin layer is formed on the particle surface and the pores are blocked.

  Accordingly, an object of the present invention is to provide a silica gel porous particle having a through-hole, having a uniform shape and not closing the through-hole, a method for producing the same, and a block copolymer for use in the production method. That is.

  In order to achieve the above object, the porous particles of the present invention are substantially spherical porous particles, and the porous particles are formed of silica gel and have a through-hole in which a porous structure is communicated. And the end of the through hole is open toward the outside of the porous particle.

The method for producing the porous particles of the present invention comprises:
A dispersion preparing step for preparing a dispersion by dispersing a porous particle material containing at least one of a silica monomer and a silica prepolymer in a dispersion medium, and a polymerization step for polymerizing the porous particle material in the dispersion And in the polymerization step, the through-hole is formed by spinodal decomposition.

  The block copolymer of the present invention is a block copolymer formed by including a hydrophobic polymer block and a hydrophilic polymer block, and in the dispersion preparation step of the porous particle production method of the present invention, the porous particle It is a block copolymer used as a dispersant for dispersing a raw material in a dispersion medium.

  The silica gel porous particles of the present invention have through-holes in the interior thereof, have a substantially spherical homogeneous shape, and the through-holes are not blocked. Further, according to the method for producing porous particles of the present invention and the block copolymer of the present invention, it is possible to produce the porous particles of the present invention having the above properties.

FIG. 1 is an enlarged photograph (magnification 100 times) of a cross-section of silica gel porous particles produced in Examples. FIG. 2 is an enlarged photograph (magnification 1000 times) of a cross section of the silica gel porous particles produced in the example. FIG. 3 is an enlarged photograph (magnification 5000 times) of the cross section of the silica gel porous particles produced in the example. FIG. 4 is an enlarged photograph (magnification 10,000 times) of a cross section of the silica gel resin porous particles produced in the example.

  Hereinafter, the present invention will be described with examples. However, the present invention is not limited by the following description.

[1. Silica gel porous particles]
As described above, the silica gel porous particles of the present invention (hereinafter sometimes simply referred to as “porous particles” or “porous particles of the present invention”) are substantially spherical. The porous particles of the present invention have, for example, a major axis (longest diameter) of 1.6 times or less, 1.4 times or less, or 1.2 times or less of a short diameter (shortest diameter), for example. The porous particles of the present invention are ideally spherical, for example, and have a major axis and a minor axis that are the same length.

  The particle diameter (particle diameter) of the porous particles of the present invention is not particularly limited, but the lower limit value of the average particle diameter is, for example, 0.5 μm, 5 μm, 7 μm, 1,000 μm (1 mm), etc. The upper limit value is, for example, 30,000 μm (30 mm), 10,000 μm (10 mm), 1,000 μm (1 mm), 700 μm, or the like. The range of the particle size (particle size) of the porous particles of the present invention is, for example, a range of 0.5 to 30,000 μm (0.5 μm to 30 mm), 1 to 10 mm, 5 to 1,000 μm, or 7 to 700 μm. It is. In the present invention, the average particle size can be measured by, for example, a laser diffraction / scattering particle size distribution measuring apparatus. Alternatively, when measurement with a laser diffraction / scattering particle size distribution measuring apparatus is difficult due to a small amount of sample, the average particle diameter may be estimated from an image of a scanning electron micrograph (SEM).

  As described above, the porous particle of the present invention is formed of silica gel, and has a through-hole in which a porous structure is communicated, and an end of the through-hole is formed on the outside of the porous particle. It is open toward. The through-hole has, for example, a bent structure as a result of the communication of the porous structure. In addition, the porous particles of the present invention are porous particles having a through-hole having a co-continuous structure (the porous structure communicates with the inside of the particle) instead of the particle aggregation type structure. In the present invention, the “particle aggregation type” porous structure means that small particles without pores are bonded to each other to form a skeleton, and at the same time, pores are formed as gaps between the particles. Refers to the structure. In the “particle aggregation type” porous structure, particles whose aggregates are substantially granular in shape are called particle aggregation type particles.

  The presence of through-holes in which the porous structure communicates in the porous particles of the present invention can be confirmed, for example, by a photograph of the cross section or surface of the porous particles of the present invention. Moreover, it can confirm that the edge part of the said through-hole is opening toward the exterior of the said porous particle by the photograph of the surface of the porous particle of this invention, for example. The porous particles of the present invention are opened toward the outside of the porous particles without clogging the end portions of the through holes, for example, because there is no skin layer (a layer covering the particle surface). doing. The presence or absence of this skin layer can also be confirmed by a photograph of the surface of the porous particles of the present invention. The porous particles are preferably separated from each other without being bonded to other porous particles.

  The porous particles of the present invention may be an aggregate of a plurality of porous particles that are separated from each other without being bonded to other porous particles. Of the aggregate of the porous particles, the number of substantially spherical porous particles (the porous particles of the present invention) is, for example, more than 50%, 70% or more, 80% or more, 90% or more, etc. May be.

  In the porous particle of the present invention, the through-hole through which the porous structure communicates may be, for example, an open cell structure having macropores connected to each other and mesopores in the walls of the macropores. The diameter of the through hole is not particularly limited, but is, for example, in the range of 10 to 1,000,000 nm (1 mm), 20 to 100,000 nm, or 30 to 50,000 nm. In addition, the hole diameter of the through hole may be hereinafter referred to as “pore diameter”. As will be described later, the pore diameter is affected by various factors during the production of the porous particles of the present invention, and the pore diameter can be adjusted by adjusting the various factors. The pore diameter is usually non-uniform, and the degree of uniformity (dispersion) varies depending on, for example, the heat distribution in the system and the influence of stirring in the polymerization reaction during the production of the porous particles of the present invention.

  The porosity (porosity) of the porous particles of the present invention is not particularly limited, and is, for example, 30 to 95% by volume, 35 to 90% by volume, or 40 to 85% by volume. The porosity (porosity) can be measured, for example, by a nitrogen adsorption method, a mercury intrusion method, a liquid chromatography method, or the like.

  As described above, the material of the porous particles of the present invention is silica gel. That is, the porous particles of the present invention may be formed of, for example, silica gel or including silica gel. In the present invention, when simply referred to as “silica gel”, unless otherwise specified, the silica gel may be, for example, inorganic silica or hybrid silica. In addition, the said inorganic silica means the silica gel which does not contain an organic group in a molecule | numerator, The said hybrid silica means the silica gel which contains an organic group in a molecule | numerator (for example, side chain etc.). The inorganic silica and hybrid silica may or may not contain heteroatoms such as nitrogen atoms and sulfur atoms in the molecule. The porous particles of the present invention may be composed of, for example, a single polymer, but may be a mixture or copolymer of a plurality of polymers. The copolymer may be, for example, a random copolymer or a block copolymer.

  Moreover, the porous particle of this invention may contain other components other than the said polymer (silica gel), and does not need to contain it. Examples of the other components include, but are not limited to, inorganic fillers (silica, calcium carbonate, talc, alumina, titanium oxide, carbon black, etc.), and organic fillers (acrylic resin particles, urethane resin). Particles, etc.), nanofibers (carbon nanofiper, cellulose nanofiber, etc.) and the like.

  Although the manufacturing method of the porous particle of this invention is not specifically limited, For example, it can manufacture with the manufacturing method of the porous particle of the said this invention.

[2. Method for producing porous particles]
As described above, the method for producing porous particles of the present invention includes a dispersion preparation step of preparing a dispersion by dispersing a porous particle material containing at least one of a monomer and a prepolymer in a dispersion medium; A polymerization step of polymerizing the conductive particle material in the dispersion, and in the polymerization step, the through holes are formed by spinodal decomposition.

  In the method for producing porous particles of the present invention, for example, in the dispersion preparation step, the porous particle raw material is dispersed in a dispersion medium together with a dispersant. The dispersant may be, for example, a surfactant.

  In the method for producing porous particles of the present invention, for example, the dispersant may be the block copolymer of the present invention formed by including a hydrophobic polymer block and a hydrophilic polymer block. In this case, for example, the method for producing porous particles of the present invention further includes a dispersant production process for producing the dispersant (the block copolymer of the present invention), and the dispersant production process is performed by living radical polymerization. A first living radical polymerization step for forming one of the hydrophobic polymer block and the hydrophilic polymer block; and after the first living radical polymerization step, the other of the hydrophobic polymer block and the hydrophilic polymer block by living radical polymerization. And a first living radical polymerization step for forming. The block copolymer of the present invention is formed to include a hydrophobic polymer block and a hydrophilic polymer block, and thus can be referred to as a “surfactant” in a broad sense.

  By the production method of the present invention, it is possible to produce porous particles having through-holes communicating with a porous structure and having a substantially spherical outer shape and having no skin layer. Although this mechanism is unknown, it is presumed that, for example, the interface between the porous particle material and the dispersion medium can be maintained in an appropriate state. Specifically, for example, by maintaining the interface in an appropriate state, the porous particle raw material can be polymerized without agglomeration, so it is considered that the through holes can be formed. Further, for example, since the porous particle material can be maintained in a state of being dispersed in the dispersion medium, it is considered that the substantially spherical porous particles of the present invention can be produced. For example, if one of the hydrophilic substance and the hydrophobic substance in the porous particle raw material is unevenly distributed at the interface, the skin layer may be formed due to polymerization or the like. Due to this skin layer, the through holes are likely to be blocked on the surface of the porous particles. However, it is possible to prevent the formation of the skin layer by controlling the ratio of the hydrophilic substance and the hydrophobic substance to an appropriate state at the interface. However, this mechanism is an example and does not limit the present invention.

  The method for maintaining the interface between the porous particle raw material and the dispersion medium in an appropriate state is not particularly limited. For example, the surfactant or the block copolymer of the present invention (dispersant) is a surfactant in a broad sense. ) Is used. In the surfactant or the block copolymer (dispersant) of the present invention, it is preferable to appropriately control the ratio of the hydrophobic part to the hydrophilic part as described later. Examples of a method for maintaining the interface between the porous particle raw material and the dispersion medium in an appropriate state include a method of physically stirring the dispersion.

  In the present invention, “spinodal decomposition” refers to a phenomenon in which a multi-component mixed system forms a co-continuous structure and phase-separates (for example, a two-component mixed system undergoes two-phase separation), or a phase-separated state. “Spinodal decomposition” may refer to the process of two-phase separation that occurs when, for example, a two-component mixed system is rapidly cooled from a high temperature and placed in an unstable state, but is not limited to the case of rapid cooling in the present invention. That is, in the present invention, the method for causing the spinodal decomposition is not particularly limited, and any method may be used. For example, the porous particle material is polymerized or cross-linked while the porous particle material is dispersed in a dispersion medium and the interface between the porous particle material and the dispersion medium is maintained in an appropriate state. It is thought that spinodal decomposition occurs and the structure is fixed. The method for maintaining the interface between the porous particle material and the dispersion medium in an appropriate state is, for example, as described above.

  Hereinafter, the method for producing porous particles of the present invention will be described more specifically.

[2-1. Dispersion]
In the production method of the present invention, first, a porous particle material containing at least one of a monomer and a prepolymer is dispersed in a dispersion medium to prepare a dispersion (dispersion preparation step). Although the said monomer and prepolymer are not specifically limited, For example, the monomer and prepolymer corresponding to each said silica gel are mentioned. More specifically, examples include TMOS (tetramethoxysilane), TEOS (tetraethoxysilane), MTMS (methoxysilane), SQ (silsesquioxane) and the like. Examples of organic / inorganic hybrid raw material monomers include, for example, organoalkoxysilanes such as methyltrimethoxysilane, vinyltrimethoxysilane, dimethyldimethoxysilane, 1,2-bistrimethoxysilylethane, and silane coupling agents. Examples include a combination of an organic polymer compound containing a reaction part and silica, and these can be used as a raw material monomer for hybrid silica, for example. Although it does not specifically limit as said dispersion medium, An organic solvent and water are mentioned, You may use individually or may use 2 or more types together. Examples of the organic solvent include hydrocarbon solvents such as hexane, octane, decane, dodecane, isodecane, cyclohexane, methylcyclohexane, toluene, xylene, ethylbenzene, cumene; methanol, ethanol, propanol, isopropanol, butanol, isobutanol, Alcohol solvents such as hexanol, benzyl alcohol, cyclohexanol; ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol propyl ether, diglyme , Triglyme, dipropylene glycol dimethyl ether Glycol solvents such as butyl carbitol, butyl triethylene glycol, methyl dipropylene glycol, methyl cellosolve acetate, propylene glycol monomethyl ether acetate, dipropylene glycol butyl ether acetate, diethylene glycol monobutyl ether acetate; diethyl ether, dipropyl ether, methylcyclopropyl Ether solvents such as ether, tetrahydrofuran, dioxane, anisole; ketone solvents such as methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, acetophenone; methyl acetate, ethyl acetate, butyl acetate, propyl acetate, methyl butyrate, ethyl butyrate , Ester solutions such as caprolactone, methyl lactate and ethyl lactate Halogenated solvents such as chloroform and dichloroethane; amide solvents such as dimethylformamide, dimethylacetamide, pyrrolidone, N-methylpyrrolidone and caprolactam; dimethyl sulfoxide, sulfolane, tetramethylurea, ethylene carbonate, propylene carbonate, dimethyl carbonate and ethyl carbonate , Nitromethane, acetonitrile, nitrobenzene, dioctyl phthalate, etc., may be used alone or in combination of two or more.

  In the dispersion, the concentration of the porous particle raw material (at least one of the monomer and the prepolymer) is not particularly limited, but for example 0.01 to 10,000 g / L, 1 to 5, with respect to the dispersion medium. 000 g / L, or 5 to 3,000 g / L.

  In the method for producing porous particles of the present invention, for example, in the dispersion preparation step, the porous particle raw material may be dispersed in a dispersion medium together with a dispersant. Although the density | concentration of the said dispersing agent is not specifically limited, For example, it is 1-500 g / L, 2-300 g / L, or 3-250 g / L with respect to the said dispersion medium.

  The dispersant may be, for example, a surfactant. The surfactant is not particularly limited. For example, an anionic surfactant, a cationic surfactant, a nonionic surfactant, a block copolymer composed of a hydrophilic block and a hydrophobic block, such as a polyacrylic acid block and a polyacrylic ester. Examples include block copolymers composed of blocks, block copolymers composed of polyoxyethylene blocks and polyacrylic ester blocks, block copolymers composed of polyoxyethylene blocks and polyoxypropylene blocks, and the like.

  Examples of the anionic surfactant include fatty acid salts, sulfate esters of higher alcohols, phosphate esters of fatty alcohols, alkyl allyl sulfonates, and formalin condensed naphthalene sulfonates. Examples of the cationic surfactant include alkyl primary amine salts, alkyl secondary amine salts, alkyl tertiary amine salts, alkyl quaternary ammonium salts, and pyridinium salts. Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, polyoxyethylene sorbitan alkyl esters, and the like. Examples of the polymer surfactant include partially saponified polyvinyl alcohol, starch, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, and partially saponified polymethacrylate.

  By selecting the surfactant to be used, the average particle size and particle size distribution of the resulting porous epoxy resin particles and the aggregation state of the particles can be controlled. For example, anionic surfactants, cationic surfactants, nonionic interfaces By using an activator, the average particle size can be reduced and the particle size distribution can be narrowed. In addition, by using a polymer surfactant, it is possible to increase the average particle diameter and to suppress aggregation of the particles. In particular, when a block copolymer consisting of a hydrophilic block and a hydrophobic block is used as a surfactant, since it can be emulsified with a small amount of addition, the viscosity of the solution during the polymerization reaction can be kept low, so stirring is easy. It is preferable.

  These surfactants may be used alone or in combination of two or more.

  Further, for example, the dispersant may be a block copolymer formed by including a hydrophobic polymer block and a hydrophilic polymer block. In this case, for example, the method for producing porous particles according to the present invention further includes a dispersant production process for producing the dispersant, and the dispersant production process is performed by living radical polymerization to form the hydrophobic polymer block and the hydrophilic polymer. A first living radical polymerization step for forming one of the hydrophilic polymer blocks, and a second living room for forming the other of the hydrophobic polymer block and the hydrophilic polymer block by living radical polymerization after the first living radical polymerization step A radical polymerization step. In addition, about the said block copolymer (dispersing agent) and the said dispersing agent manufacturing process, it mentions later [2-2. Block copolymer (dispersant) and dispersant production process] will be described in detail.

  In the dispersion preparation step, the dispersion may contain components other than the porous particle raw material and the dispersant. The other components are not particularly limited, and examples thereof include other surfactants other than nonionic surfactants and antifoaming agents as long as they do not affect the original dispersion.

[2-2. Block copolymer (dispersant) and dispersant production process]
Hereinafter, the block copolymer (dispersant) and the dispersant production process will be described in detail.

  First, since the block copolymer is formed to include a hydrophobic polymer block and a hydrophilic polymer block, as described above, it can be called a “surfactant” in a broad sense. The block copolymer and the dispersant production process may be the same as or similar to those described in JP-A-2015-83688, for example, or may be referred to. Specifically, for example, it is as follows.

  The block copolymer includes, for example, the hydrophobic polymer block (hereinafter sometimes simply referred to as “hydrophobic block” or “hydrophobic block A” or “A block”)-the hydrophilic polymer block (hereinafter simply referred to as “ It may be a diblock copolymer consisting of “hydrophilic block” or “hydrophilic block B” or “B block”. The block copolymer is, for example, a block copolymer obtained by polymerizing an addition polymerizable monomer using a radical generator using an organic iodide as a polymerization initiator compound and an organic phosphorus compound, an organic nitrogen compound or an organic oxygen compound as a catalyst. It may be.

  In the block copolymer molecule, the content of the A block (hydrophobic block) is, for example, 5 to 95% by mass, 10 to 90% by mass, 15 to 85% by mass, or 20 to 80% by mass. In the block copolymer molecule, the content of the B block (hydrophilic block) is, for example, 5 to 95% by mass, 10 to 90% by mass, 15 to 85% by mass, or 20 to 80% by mass. .

  The hydrophobic monomer that is the raw material of the A block (hydrophobic block) is, for example, a (meth) acrylate having a hydrophobic group ((meth) acrylic acid ester), a vinyl compound having a hydrophobic group, or an allyl having a hydrophobic group. Compounds, and the like. The hydrophilic monomer that is a raw material of the B block (hydrophilic block) is, for example, a (meth) acrylate having a hydrophilic group ((meth) acrylic acid ester), a vinyl compound having a hydrophilic group, an allyl compound having a hydrophilic group, Etc. For example, the hydrophobic monomer may contain lauryl (meth) acrylate, and the hydrophilic monomer may contain polyethylene glycol methacrylate. In the present invention, “(meth) acryl” means one or both of “acryl” and “methacryl”, and “(co) polymerization” means one or both of “polymerization” and “copolymerization”. means. The same applies to “(meth) acrylate”. "(Poly) alkylene ..." means one or both of "alkylene ..." and "polyalkylene ...". The same applies to "(poly) ethylene ...".

  As described above, the dispersant (block copolymer) may have a diblock structure including the hydrophobic polymer block A and the hydrophilic polymer block B (hereinafter, referred to as “AB diblock polymer”). )is there. For example, in the dispersion preparation step, the dispersant (block copolymer) is dispersed in the dispersion medium together with the porous particle material (including at least one of a monomer and a prepolymer). When the porous particle material is relatively hydrophilic with respect to the dispersion medium, for example, the hydrophilic polymer block B is adsorbed on the porous particle material, and the particles formed by aggregation of the porous particle material The surface is coated with a hydrophobic polymer block A. As a result, the hydrophobic polymer block A is in a shape facing the hydrophobic dispersion medium. Conversely, when the porous particle material is relatively hydrophobic with respect to the dispersion medium, for example, the hydrophobic polymer block A is adsorbed on the porous particle material, and the porous particle material aggregates. The surface of the particles is covered with the hydrophilic polymer block B. Thereby, the hydrophilic polymer block B becomes a shape facing the hydrophilic dispersion medium. In this way, the porous particle material can be dispersed in the dispersion medium in the form of particles. This state can also be referred to as a state in which the porous particle material is emulsified (suspended) in the dispersion medium, for example. Thereby, for example, the dispersion stability and storage stability of the dispersion before and after the polymerization can be improved.

  The porous particle raw material (including at least one of a monomer and a prepolymer) is as described above. For example, the porous raw material is at least one of a radically polymerizable or thermosetting monomer and a prepolymer. May be included. The monomer and prepolymer may be, for example, a hydrophilic monomer and prepolymer.

Next, the method for producing the block copolymer (dispersant) uses, for example, a radical generator as described above, using an organic iodide as a polymerization initiating compound and an organic phosphorus compound, organic nitrogen compound or organic oxygen compound as a catalyst. Alternatively, a production method of polymerizing addition polymerizable monomers (hydrophobic monomer and hydrophilic monomer) may be used. Such a manufacturing method is described in, for example, JP-A-2015-83688. According to this manufacturing method, there are no problems such as heavy metal, odor, coloring, and cost. Specifically, for example, there are the following advantages (1) to (6).

(1) Do not use heavy metal compounds; do not use heavy metal compounds such as ATRP method and DT method.
(2) Purification is not essential; the ATRP method and DT method require removal of heavy metals, and the RAFT method and MADIX method require removal of sulfur compounds.
(3) Special and expensive compounds are not required, relatively inexpensive materials on the market can be used, and thus low cost; other living radical polymerization methods require special compounds.
(4) The polymerization conditions are mild, and the polymerization can be carried out under the same conditions as in the conventional radical polymerization method; the NMP method requires a high temperature and the ATRP method requires removal of oxygen.
(5) It is not necessary to purify the monomers and solvents used, and various monomers can be used. Monomers having various functional groups such as acid groups and amino groups can be used, and various types of polymer blocks can be used. Functional groups can be introduced; in particular, in the ATRP method, acid groups become their catalyst poisons, and acid groups cannot be used as they are. In the NMP method, methacrylate does not polymerize well.
(6) The molecular weight and structure can be controlled, a block polymer in a desired bonded state can be easily obtained, and the polymerization rate is very good.

  In addition, the said description is an illustration, Comprising: In this invention, the manufacturing method of the said block copolymer (dispersant) is not specifically limited. That is, the method for producing the block copolymer (dispersant) is not limited to the method described in JP-A-2015-83688, and any production method may be used.

  Although it does not specifically limit as a hydrophobic monomer which forms the said A block, For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, 2 -Methylpropane (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl ( (Meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, tetradecyl (meth) acrylate, octadecyl (meth) acrylate, behenyl (meth) acrylate, isostearyl (meth) a Relate, cyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 2,2,4-trimethylcyclohexyl (meth) acrylate, cyclodecyl (meth) acrylate, cyclodecylmethyl (meth) acrylate, Aliphatic, alicyclic, aromatic alkyl (meth) such as benzyl (meth) acrylate, t-butylbenzotriazole phenylethyl (meth) acrylate, phenyl (meth) acrylate, naphthyl (meth) acrylate, allyl (meth) acrylate An acrylate etc. are mentioned, The thing with long alkyl groups, such as a lauryl (meth) acrylate, is especially preferable. The hydrophobic monomer may be used alone or in combination.

  The hydrophilic monomer constituting the B block is not particularly limited, and examples thereof include a monomer having a polyglycol group. More specifically, for example, poly (n = 2 or more) ethylene glycol mono (meth) acrylate, Poly (n = 2 or more) propylene glycol mono (meth) acrylate, poly (n = 2 or more) tetramethylene glycol mono (meth) acrylate, mono or poly (n = 2 or more) ethylene glycol mono or poly (n = 2 or more) ) Polyalkylene glycol mono, such as mono (meth) acrylate of propylene glycol random copolymer, mono or poly (n = 2 or more) ethylene glycol mono or poly (n = 2 or more) propylene glycol block copolymer mono (meth) acrylate, etc. (Meth) acrylate, (Poly) ethylene glycol monomethyl ether (meth) acrylate, (poly) ethylene glycol monooctyl ether (meth) acrylate, (poly) ethylene glycol monolauryl ether (meth) acrylate, (poly) ethylene glycol monostearyl ether ( (Meth) acrylate, (poly) ethylene glycol monooleyl ether (meth) acrylate, (poly) ethylene glycol monostearate (meth) acrylate, (poly) ethylene glycol monononylphenyl ether (meth) acrylate, (poly) propylene glycol Monomethyl ether (meth) acrylate, (poly) propylene glycol monoethyl ether (meth) acrylate, (poly) propylene glycol monooct (Polyalkylene) glycol monoalkyl, alkylene, alkyne ether, such as ruether (meth) acrylate, (poly) propylene glycol monolauryl ether (meth) acrylate, (poly) ethylene glycol (poly) propylene glycol monomethyl ether (meth) acrylate, or Examples thereof include mono (meth) acrylates of esters, and poly (n = 6 or more) ethylene glycol mono (meth) acrylate is particularly desirable. In addition, said n represents the polymerization degree in the said polyglycol group. The hydrophilic monomer may be used alone or in combination.

  Further, the block copolymer (dispersant) may be formed only from the hydrophobic polymer block A (A block) and the hydrophilic polymer block B (B block), but includes other components ( It may be copolymerized). Examples of monomers that can be copolymerized within a range that does not change the basic properties of the A block and B block include conventionally known monomers, such as styrene, vinyl toluene, vinyl hydroxybenzene, chloromethyl styrene, vinyl naphthalene, vinyl. Biphenyl, vinylethylbenzene, vinyldimethylbenzene, α-methylstyrene, ethylene, propylene, isoprene, butene, butadiene, 1-hexene, cyclohexene, cyclodecene, dichloroethylene, chloroethylene, fluoroethylene, tetrafluoroethylene, acrylonitrile, methacrylonitrile, Vinyl acetate, vinyl propionate, isocyanatodimethylmethane isopropenylbenzene, phenylmaleimide, cyclohexylmaleimide, hydroxymethylstyrene, etc. As vinyl monomers and hydroxyl group-containing monomers, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxy Mono (meth) acrylic esters of alkylene glycols such as hexyl (meth) acrylate, cyclohexanedimethanol mono (meth) acrylate, cyclohexanediol mono (meth) acrylate, and other monomers include (meth) acryloyl Ring opening of lactones such as (poly) alkylene glycol mono (meth) acrylates such as loxyethyl mono or poly (n = 2 or more) caprolactone, ε-caprolactone and γ-butyrolactone Polyester mono (meth) acrylic acid ester obtained by combining; 2- (meth) acryloyloxyethyl-2-hydroxyethyl phthalate, 2- (meth) acryloyloxyethyl-2-hydroxyethyl succinate, etc. Ester-based (meth) acrylate obtained by reacting the above (poly) alkylene glycol mono (meth) acrylic ester with a dibasic acid to form a half ester, and then reacting the other carboxyl group with alcohol or alkylene glycol; glycerol Mono (meth) acrylates of polyfunctional hydroxyl compounds having three or more hydroxyl groups such as mono (meth) acrylate and dimethylolpropane mono (meth) acrylate; 3-chloro-2-hydroxypropyl (meth) acrylate, octafluorooctyl (Meta) Acry Rate, halogen-containing (meth) acrylates such as tetrafluoroethyl (meth) acrylate; 2- (4-benzoxy-3-hydroxyphenoxy) ethyl (meth) acrylate, 2- (2′-hydroxy-5- (meth)) UV-absorbing monomers such as acryloyloxyethylphenyl) -2H-benzotriazole, especially this monomer may be copolymerized to improve the light resistance of the dye; α-hydroxyl methyl such as ethyl-α-hydroxymethyl acrylate Examples thereof include substituted acrylates.

  The molecular weight of the block copolymer (dispersant) is not particularly limited, but is a number average molecular weight in terms of styrene in gel permeation chromatography (hereinafter GPC) (hereinafter the number average molecular weight refers to styrene equivalent of GPC, and simply referred to as molecular weight). For example, it is 1,000 or more, 1,500 or more, 2,000 or more, or 3,000 or more, for example, 300,000 or less, 100,000 or less, or 50,000 or less. The range of the molecular weight is, for example, 1,000 to 300,000, preferably 1,500 to 100,000, more preferably 2,000 to 50,000, and further preferably 3,000 to 50,000. From the viewpoint of the dispersion stability of the porous particle material in the dispersion medium, the block copolymer (dispersant) preferably has a molecular weight of 1,000 or more. In addition, from the viewpoint of solubility of the block copolymer (dispersant) in the dispersion medium, the molecular weight of the block copolymer (dispersant) is preferably 300,000 or less. If the molecular weight of the block copolymer (dispersant) is too large, aggregation of the dispersants in the dispersion medium and entanglement between the molecules may become too strong, and the porous particle material may not be dispersed.

  The degree of dispersion (hereinafter referred to as PDI) which is the ratio of the weight average molecular weight to the number average molecular weight in the block copolymer (dispersant) is not particularly limited. In living radical polymerization, it can be a polymer dispersant of very small PDI (˜1.3), but in the present invention, it is important that the block copolymer (dispersant) takes the block structure described above, PDI is not greatly involved. However, if the PDI is too wide, the block copolymer (dispersing agent) includes a polymer having a high molecular weight to a polymer having a low molecular weight, and a phenomenon other than the above-described molecular weight range may occur. In the block copolymer (dispersant) used in the present invention, PDI is preferably 2.0 or less, more preferably 1.8 or less.

  Next, the mass ratio of the hydrophobic block and the hydrophilic block in the block copolymer (dispersant) is not particularly limited, and is, for example, as described above. By appropriately controlling the mass ratio of the hydrophobic block and the hydrophilic block, for example, in the method for producing porous particles of the present invention, the interface between the porous particle raw material and the dispersion medium is maintained in an appropriate state. can do. Thereby, for example, since the porous particle material can be maintained in a state of being dispersed in the dispersion medium, the substantially spherical porous particles of the present invention can be produced. Further, for example, by appropriately controlling the mass ratio of the hydrophobic block to the hydrophilic block, the ratio of the hydrophilic substance to the hydrophobic substance can be appropriately set at the interface between the porous particle raw material and the dispersion medium. The state can be controlled. For example, when one of the hydrophilic substance and the hydrophobic substance is unevenly distributed at the interface, the skin layer may be formed due to polymerization or the like. Due to this skin layer, the through holes are likely to be blocked on the surface of the porous particles. However, it is possible to prevent the formation of the skin layer by controlling the ratio of the hydrophilic substance and the hydrophobic substance to an appropriate state at the interface. However, these descriptions are merely examples and do not limit the present invention.

  Next, a polymerization method (manufacturing method) for obtaining the block copolymer (dispersant) used in the present invention will be described. Although this polymerization method is not particularly limited, for example, as described above, an addition polymerizable monomer using an organic iodide as a polymerization initiating compound and an organic phosphorus compound, an organic nitrogen compound or an organic oxygen compound as a catalyst and using a radical generator. A method of polymerizing (hydrophobic monomer and hydrophilic monomer) may also be used. This polymerization method does not use metal compounds or ligands, and does not require the use of special compounds such as nitroxides, dithiocarboxylic acid esters, and xanthates, and is a conventional addition-polymerizable monomer and polymerization initiator that is a radical generator. This is a living radical polymerization that can be easily carried out by using a starting compound, which is an organic iodide, and a catalyst in combination with the radical polymerization using a catalyst.

The polymerization method is represented by the following general reaction formula 1
It is considered that the reaction mechanism is a reversible active reaction to the growth radical of the dormant species Polymer-X (PX). This polymerization mechanism may vary depending on the type of catalyst, but is thought to proceed as follows. In the above formula 1, P · generated from the polymerization initiator reacts with XA to produce catalyst A · in situ. A. acts as an activator of PX, and this catalysis activates PX at a high frequency.

  More specifically, the radical generated from the polymerization initiator in the presence of the initiator compound to which iodine (X) is bonded draws the active hydrogen or active halogen atom of the catalyst to become the catalyst radical A. Then, A. withdraws X of the starting compound to become XA, and the starting compound becomes a radical, and the monomer is polymerized to the radical, and X is immediately withdrawn from XA to prevent the termination reaction. Further, A. withdraws X from the terminal X by heat or the like, becomes XA and a terminal radical, the monomer reacts there, and immediately gives X to the terminal radical and stabilizes. By repeating this, polymerization proceeds and the molecular weight and structure can be controlled. However, in some cases, a bimolecular termination reaction or disproportionation may be involved as a side reaction.

  The starting compound for initiating the living radical polymerization is a conventionally known organic iodide and is not particularly limited. Specific examples include methyl iodide, ethyl iodide, propyl iodide, isopropyl iodide, butyl iodide, t-butyl iodide; iodophenylmethane, iododiphenylmethane, iodotriphenylmethane, 2-iodo. Alkyl iodides such as -1-phenylethane, 1-iodo-1-phenylethane, 1-iodo-1,1-diphenylethane, diiodomethane; iododichloromethane, iodochloromethane, iodotrichloromethane, iododibromomethane Organic halides containing iodine atoms such as 1-iodoethanol, 1-iodopropanol, 2-iodopropanol, 2-iodo-2-propanol, 2-iodo-2-methylpropanol, 2-phenyl-1 -Iodoethanol, 2-Fe Iodinated alcohols such as lu-2-iodoethanol; ester compounds of these iodide alcohols with carboxylic acid compounds such as acetic acid, butyric acid and fumaric acid; iodoacetic acid, α-iodopropionic acid, α-iodobutyric acid, α-iodoisobutyric acid, α-iodovaleric acid, α-iodoisovaleric acid, α-iodocaproic acid, α-iodophenylacetic acid, α-iododiphenylacetic acid, α-iodo-α-phenylpropionic acid, α- Iodo-β-phenylpropionic acid, β-iodopropionic acid, β-iodobutyric acid, β-iodoisobutyric acid, β-iodovaleric acid, β-iodoisovaleric acid, β-iodocaproic acid, β-iodophenylacetic acid , Β-iododiphenylacetic acid, β-iodo-α-phenylpropionic acid, β-iodo-β-phenylpropionic acid Iodinated carboxylic acids such as acids; esterified products of these iodinated carboxylic acids with methanol, ethanol, phenol, benzyl alcohol, and the above-described iodinated alcohols; acid anhydrides of these iodinated carboxylic acids; Acid anhydrides such as carboxylic acid chloride and bromide; iodoacetonitrile, 2-cyano-2-iodopropane, 2-cyano-2-iodobutane, 1-cyano-1-iodocyclohexane, 2-cyano-2 -Cyano group-containing iodides such as iodovaleronitrile. Bifunctional starting compounds having two iodines can also be used, such as 1,2-diaiodoethane, 1,2-diaiodotetrafluoroethane, 1,2-diaiodotetrachloroethane, 1,2-diaiodo-1- Examples thereof include phenylethane, a reaction product of an iodinated carboxylic acid such as α-iodoisobutyric acid and a diol such as ethylene glycol and a diamine such as hexamethylenediamine. “Iodo” is synonymous with “iodo” and represents iodide. The same applies to the following. Moreover, the said starter compound may be used individually or may be used together 2 or more types.

  Moreover, these compounds may use a commercial item as it is, for example, and can also be obtained by a conventionally well-known method. For example, an organic halide obtained by the reaction of an azo compound such as azobisisobutyronitrile and iodine, or an organic halide in which other halogen atoms such as bromide or chloride are substituted in place of iodine of the organic iodide described above is used. An organic iodide used in the present invention can be obtained by performing a halogen exchange reaction using an iodide salt such as quaternary ammonium iodide or sodium iodide. They are not particularly limited.

  Examples of the catalyst include an organic phosphorus compound, an organic nitrogen compound, or an organic oxygen compound that extracts an iodine atom of the starting compound and becomes a radical, preferably a phosphorus halide or phosphite compound containing an iodine atom. Selected from one or more of organic phosphorus compounds that are phosphinate compounds, imide compounds, organic nitrogen compounds that are hydantoin compounds, phenolic compounds, iodooxyphenyl compounds, and organic oxygen compounds that are vitamins It is. Although these compounds are not particularly limited, specific examples thereof include phosphorus halides containing iodine atoms, phosphite compounds, and phosphinate compounds, such as dichloroiodolin, dibromoiodolin, Phosphorus triiodide, dimethyl phosphite, diethyl phosphite, dibutyl phosphite, diperfluoroethyl phosphinate, diphenyl phosphite, dibenzyl phosphite, bis (2-ethylhexyl) phosphite, bis (2,2,2 -Trifluoroethyl) phosphite, diallyl phosphite, ethylene phosphite, ethoxyphenyl phosphinate, phenylphenoxy phosphinate, ethoxymethyl phosphinate, phenoxymethyl phosphinate And the like. Nitrogen compounds include imide compounds and hydantoin compounds such as succinimide, 2,2-dimethylsuccinimide, α, α-dimethyl-β-methylsuccinimide, 3-ethyl-3-methyl-2,5-pyrrolidinedione, Cis-1,2,3,6-tetrahydrophthalimide, α-methyl-α-propylsuccinimide, 5-methylhexahydroisoindole-1,3-dione, 2-phenylsuccinimide, α-methyl-α-phenylsuccinimide, 2,3-diacetoxysuccinimide, maleimide, phthalimide, 4-methylphthalimide, N-chlorophthalimide, N-bromophthalimide, N-bromophthalimide, 4-nitrophthalimide, 2,3-naphthalenecarboximide, pyromellitic diimide, 5 -Bromoy Indole-1,3-dione, N- chlorosuccinimide, N- bromosuccinimide, N- eye odometer succinimide, hydantoin, and the like Giay odo hydantoin. Examples of oxygen compounds include phenolic compounds that are phenolic hydroxyl groups having a hydroxyl group in the aromatic ring, iodooxyphenyl compounds that are iodinated products of the phenolic hydroxyl groups, and vitamins. For example, phenols such as phenol, hydroquinone, methoxy Hydroquinone, t-butylphenol, t-butylmethylphenol, catechol, resorcinol, di-t-butylhydroxytoluene, dimethylphenol, trimethylphenol, di-t-butylmethoxyphenol, hydroxystyrene polymer or its hydroxyphenyl group Examples thereof include polymer fine particles. Since these are added as a polymerization inhibitor for storage of the monomer, the effect can be exhibited by using the commercially available monomer as it is without purification. Examples of the iodooxyphenyl compound include thymol diiodide, and examples of vitamins include vitamin C and vitamin E.

  The amount of the catalyst is not particularly limited, but is, for example, less than the number of moles of the polymerization initiator. If the number of moles of the catalyst is too large, the polymerization is too controlled and the polymerization may not proceed.

  Next, the polymerization initiator used in the present invention is not particularly limited, but conventionally known polymerization initiators such as commonly used organic peroxides and azo compounds can be used. Specific examples include benzoyl peroxide, dicumyl peroxide, diisopropyl peroxide, di-t-butyl peroxide, t-butyl peroxybenzoate, t-hexyl peroxybenzoate, t-butyl peroxy-2-ethylhexa Noate, t-hexylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-bis (t -Butylperoxy) hexyl-3,3-isopropyl hydroperoxide, t-butyl hydroperoxide, dicumyl hydroperoxide, acetyl peroxide, bis (4-t-butylcyclohexyl) peroxydicarbonate, isobutyl peroxide 3,3,5-trimethylhexanoylpa Oxide, lauryl peroxide, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane, 2, 2'-azobis (isobutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (isobutyrate), 2,2'-azobis (methoxydimethylvaleronitrile), etc. One type may be used or two or more types may be used in combination.

  Although the usage-amount of the said polymerization initiator is not specifically limited, For example, it is 0.001-0.1 mol times with respect to the monomer mole number, More preferably, it is 0.002-0.05 mol times. If the amount of the polymerization initiator used is too small, the polymerization may be insufficient, and if it is too large, a polymer containing only the addition polymerization monomer may be formed.

  As described above, the block copolymer (dispersant) used in the present invention can be obtained by polymerization using at least an initiator compound, an addition polymerizable monomer, a polymerization initiator and a catalyst which are organic iodides. The polymerization may be carried out in bulk without using an organic solvent, but solution polymerization using a solvent is preferred. The organic solvent to be used is not particularly limited as long as it is a solvent that dissolves the organic iodide, catalyst, addition polymerizable monomer, and polymerization initiator used in the present invention. Examples of the organic solvent include hydrocarbon solvents such as hexane, octane, decane, isodecane, cyclohexane, methylcyclohexane, toluene, xylene, ethylbenzene, cumene; methanol, ethanol, propanol, isopropanol, butanol, isobutanol, hexanol, benzyl Alcohol solvents such as alcohol and cyclohexanol; ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol propyl ether, diglyme, triglyme, Dipropylene glycol dimethyl ether, butyl carb Glycol solvents such as ethanol, butyltriethylene glycol, methyl dipropylene glycol, methyl cellosolve acetate, propylene glycol monomethyl ether acetate, dipropylene glycol butyl ether acetate, diethylene glycol monobutyl ether acetate; diethyl ether, dipropyl ether, methylcyclopropyl ether Ether solvents such as tetrahydrofuran, dioxane and anisole; ketone solvents such as methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone and acetophenone; methyl acetate, ethyl acetate, butyl acetate, propyl acetate, methyl butyrate, ethyl butyrate, Ester solvents such as caprolactone, methyl lactate and ethyl lactate; Halogenated solvents such as dichloroethane; amide solvents such as dimethylformamide, dimethylacetamide, pyrrolidone, N-methylpyrrolidone, caprolactam; dimethyl sulfoxide, sulfolane, tetramethylurea, ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl carbonate, nitromethane , Acetonitrile, nitrobenzene, dioctyl phthalate and the like, and only one type may be used or two or more types may be used in combination.

  Although it does not specifically limit as solid content (monomer concentration) of a polymerization liquid, For example, it is 5-80 mass%, Preferably it is 20-60 mass%. From the viewpoint of smoothly completing the polymerization, the monomer concentration is preferably not too low. Moreover, it is preferable that the monomer concentration is not too high from the viewpoint of preventing the viscosity of the polymerization solution from becoming excessively high and stirring becomes difficult or the polymerization rate is deteriorated.

  The polymerization temperature is not particularly limited, and is 0 ° C to 150 ° C, more preferably 30 ° C to 120 ° C. The polymerization temperature is adjusted by the half-life of each polymerization initiator. The polymerization time is preferably continued until the monomer runs out, but is not particularly limited. For example, 0.5 to 48 hours, preferably 1 to 24 hours, more preferably 2 hours as a practical time. Time to 12 hours.

  The atmosphere of the polymerization reaction is not particularly limited, and may be polymerized as it is, for example, in the air, that is, oxygen may exist in the normal range in the system, and oxygen is removed as necessary. Therefore, it may be performed under a nitrogen or argon stream. Moreover, although the material to be used may remove impurities by distillation, activated carbon or alumina, a commercially available product can be used as it is. Further, the polymerization may be performed under light shielding, and there is no problem even if it is performed in a transparent container such as glass.

  The operation and mechanism of the production method (polymerization method) of the block copolymer (dispersant) are, for example, as follows. First, using a monofunctional organic iodide as an initiation compound, an addition polymerizable monomer having at least an acid group is polymerized by the above method to obtain one polymer block (referred to as an A block). This polymer terminal is stabilized because it is substituted with an iodine group, and the monomer can be added again and dissociated by heat or the like, or a little more radical initiator can be added to start the polymerization again.

  This A block is taken out, purified, dissolved again in an organic solvent, and this is used as a starting compound, and the following monomers are added, preferably by adding a catalyst and a polymerization initiator, and polymerizing the polymer terminal iodine. Dissociates and polymerization starts again, and a diblock polymer in which the B block is linked to the A block can be obtained. Further, after forming the A block, the block copolymer (dispersing agent) can be obtained by adding the B block monomer as it is without taking out the polymer, and preferably performing polymerization by adding a catalyst and a polymerization initiator.

  Similarly, the production of the above block is reversed, the B block monomer which is a hydrophilic polymer is polymerized first, and then the monomer containing at least a monomer having a hydrophobic group is polymerized to obtain a diblock of AB. A polymer (the block copolymer) may be obtained.

In the polymerization used in the present invention, for example, the molecular weight of the polymer can be controlled by the amount of the starting compound. More specifically, for example, by setting the number of moles of the monomer with respect to the number of moles of the starting compound, an arbitrary molecular weight or the magnitude of the molecular weight can be controlled. For example, when 1 mol of the starting compound is used and 500 mol of the monomer having a molecular weight of 100 is used for polymerization, a theoretical molecular weight of 1 × 100 × 500 = 50,000 is given, that is, as the set molecular weight,
[1 mol of starting compound × monomer molecular weight × monomer to starting compound molar ratio]
Can be calculated.

  However, the polymerization method used in the present invention may involve a bimolecular termination or a disproportionation side reaction, and may not achieve the above theoretical molecular weight. Polymers without these side reactions are preferred, but they can be coupled to increase molecular weight or stopped to decrease molecular weight. Further, the polymerization rate may not be 100%, the remaining monomer is distilled off, removed when the block polymer is precipitated, or after obtaining a desired block polymer, a polymerization initiator or a catalyst is added. The polymerization may be completed. The diblock polymer used in the present invention may be produced and contained, and there is no problem even if each block polymer unit is included. Preferably, the block copolymer (dispersant) may contain the block polymer of the present invention in an amount of 50% by mass or more, more preferably 80% by mass or more. Further, PDI is broadened by accompanying the above-mentioned side reaction, but the PDI is not particularly limited, and is preferably 2.0 or less, more preferably 1.8 or less.

  As described above, the block copolymer (dispersant) used in the present invention is polymerized by using at least an addition polymerizable monomer, a polymerization initiator, and a catalyst, with an organic iodide as the starting compound, and the diblock polymer used in the present invention. Can be obtained. However, as described above, this production method (polymerization method) is arbitrary, and the block copolymer (dispersant) used in the present invention may be produced by any method.

[2-3. Production of porous particles by polymerization]
Specifically, the method for producing porous particles of the present invention can be performed, for example, as follows.

  First, a porous particle material containing at least one of a monomer and a prepolymer is dispersed in a dispersion medium to which the block copolymer (dispersant) has been added in advance to prepare a dispersion (dispersion preparation step). The porous particle material is as described above. Specifically, in the dispersion liquid adjusting step, for example, a porous particle raw material containing at least one of a silica monomer and a silica prepolymer and containing a solvent that becomes a porogen and the block copolymer (dispersant) are added in advance. The porous organic material is dispersed in the form of particles in the hydrophobic organic solvent by mixing with the hydrophobic organic solvent (dispersion medium). Then, for example, the polymerization step is performed by heating the dispersion. And the porous particle made from a silica gel is obtained by superposition | polymerization (polymerization process). Thereafter, if necessary, the solvent, unreacted substances and the like are removed from the porous particles.

  The raw material silica monomer and silica prepolymer are as described above. Of these, silica monomers and silica prepolymers that are soluble in porogens are particularly preferred.

  In the present invention, the term “porogen” refers to an inert solvent or inert solvent mixture as a pore-forming agent. Porogen is present in a polymerization reaction that forms a porous polymer at a certain stage of polymerization, and is removed from the reaction mixture at a predetermined stage, whereby a porous body having a three-dimensional network skeleton structure and communicating voids Is obtained.

  In the present invention, the porogen is, for example, a solvent capable of dissolving the porous particle raw material and causing reaction-induced phase separation after the porous particle raw material is polymerized. Examples of the porogen include cellosolves such as methyl cellosolve and ethyl cellosolve, esters such as ethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate, and glycols such as polyethylene glycol and polypropylene glycol. Among them, polyethylene glycol, methyl cellosolve, ethyl cellosolve, ethylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether acetate having a molecular weight of about 200 to 20,000 are preferable, and polyethylene glycol and propylene glycol monomethyl ether acetate having a molecular weight of about 200 to 20,000 are particularly preferable. preferable. The porogen may be used alone or in combination of two or more.

  In the present invention, it is desirable to use a polyalkylene glycol or a polyalkylene glycol derivative having a hydroxyl group and having a hydroxyl value of 100 (mgKOH / g) or more as the porogen. When the hydroxyl value is smaller than 100 (mgKOH / g), the viscosity increases, and it becomes difficult to increase the pore diameter of the formed silica gel porous body, or the effect of imparting hydrophilicity to the silica gel porous body decreases. Sometimes. There is a close relationship between the amount of hydroxyl groups on the surface of the silica gel porous body and the hydroxyl equivalent of the porogen. As the hydroxyl value of the porogen decreases, the amount of hydroxyl groups that appear on the surface of the silica gel porous body also decreases and the surface hydrophilicity decreases. It is thought to do.

  In addition, as described above, the porous particle raw material contains, for example, a solvent that becomes a porogen while containing at least one of a silica monomer and a silica prepolymer. This porous particle raw material can be prepared, for example, by mixing and homogenizing at least one of the silica monomer and the silica prepolymer with the porogen.

  The content ratio of the solvent serving as a porogen in the raw material of the porous particles affects, for example, the pore diameter and pore distribution of the resulting porous epoxy resin particles. When the porogen content is large, the pore diameter is large and small. And the pore diameter tends to be small. When the porogen content is high, the pore distribution is broad, and when it is low, the content tends to be sharp.

  The content ratio of the porogen solvent in the porous particle material is preferably 50 to 300% by weight with respect to at least one of the silica monomer and the silica prepolymer contained in the porous particle material. More preferably, it is -200 weight%. When the porogen content is not less than the above lower limit, a porous structure having a higher porosity can be formed. On the other hand, when the porogen content is not more than the above upper limit, the porosity of the obtained porous particles is suppressed to an appropriate range. The mechanical strength tends to be improved.

  The method for preparing the porous particle raw material is not particularly limited, and a method of mixing at least one of the silica monomer and the silica prepolymer at room temperature or while heating may be employed, and at room temperature or while heating. A method in which at least one of the silica monomer and the silica prepolymer is added to the porogen and mixed or dissolved may be employed.

  Next, in the dispersion preparation step, for example, if the shearing force is sufficiently applied and stirred, the porous particle raw material can be dispersed in the form of particles. In this case, an appropriate method can be taken in consideration of the size and particle size distribution of the particles. For example, as a method for dispersing the porous particle raw material, a method that can give a sufficient shearing force may be used. More specifically, for example, not only devices having various shapes of stirring blades such as a propeller type, a paddle type, a turbine type, and a screw type, but also the content liquid by rotating the rotating / revolving mixer and the bottom of a test tube at high speed. Known methods such as “vortex mixer”, ultrasonic stirring, and membrane emulsification method can be used. It is preferable to select a method that makes the particle size as constant as possible.

  In the dispersion liquid adjusting step, as described above, for example, the porous particle raw material is mixed with the hydrophobic organic solvent (dispersion medium) to which the block copolymer (dispersing agent) has been added in advance. The particle raw material may be dispersed in the form of particles in a hydrophobic organic solvent. In the hydrophobic organic solvent (dispersion medium) to which the block copolymer (dispersing agent) has been added in advance, the concentration of the block copolymer (dispersing agent) is not particularly limited. For example, as described above, 1 to 500 g / L, It is 2-300 g / L, or 3-250 g / L. When the block copolymer concentration is not less than the above lower limit, the particle size can be easily controlled or aggregation during polymerization can be suppressed. When the block copolymer concentration is not more than the above upper limit, bubbles can be formed during polymerization or the viscosity can be increased. It can suppress and manufacture becomes easy. And as above-mentioned, the following superposition | polymerization process can be performed in the state which formed the water-in-oil type emulsion in which the said porous particle raw material was disperse | distributed to the hydrophobic organic solvent at the particle form.

  In the polymerization step of polymerizing the porous particle raw material in the dispersion, the amount of the dispersant (for example, the block copolymer or the surfactant) used is not particularly limited, but the silica monomer and the silica prepolymer are not limited. , And the total amount of porogen, for example, about 1 to 20% by weight, or about 2 to 10% by weight. The amount of the dispersant used affects, for example, the average particle size and particle size distribution of the obtained porous particles and the aggregation of the particles. When the amount of the dispersant used is large, the average particle size, particle size distribution, and particle aggregation can be controlled, and when the amount is small, foaming and viscosity tend to be kept low. Therefore, when the amount of the dispersant used is equal to or more than the above lower limit, the raw material mixture can be uniformly emulsified and the particle size distribution can be made narrow, or the aggregation of particles can be suppressed. Moreover, the foaming and a raise of a viscosity can be suppressed as it is below the said upper limit, and manufacture becomes easy.

  In the polymerization step, the reaction temperature is not particularly limited and can be set as appropriate. The reaction temperature is basically determined by the raw material monomer and the raw material prepolymer, and also varies depending on the stirring speed, porogen, amount of surfactant used, etc., for example, 20 to 250 ° C., 40 to 220 ° C., or 50-200 ° C. The said heating temperature influences the pore diameter of the porous particle obtained, for example. When the heating temperature is high, the pore diameter of the obtained porous particles tends to be small, and when the heating temperature is low, the pore diameter of the obtained porous particles tends to be large. When the heating temperature is moderately high, the addition polymerization reaction proceeds smoothly. When the heating temperature is moderately low, the reaction rate is prevented from becoming too fast, and a porous structure can be successfully formed.

  In the polymerization step, the reaction time is not particularly limited and can be set as appropriate. Although the said reaction time changes also with stirring rates, heating temperature, porogen, the usage-amount of surfactant, etc., it is 0.01-100 hr, 0.05-24 hr, or 0.1-20 hr, for example. The reaction time affects, for example, the reaction rate of the obtained porous particles. If the reaction time is long, the reaction rate is high and there is little unreacted material, so the mechanical strength tends to be high. If the reaction time is short, the reaction rate is low and there are many unreacted materials, so the mechanical strength tends to be low. If the reaction time is moderately long, the addition polymerization reaction proceeds sufficiently to form a desired porous structure, and if it is moderately short, the possibility of crushing by stirring can be reduced.

  In the polymerization step, it is preferable to carry out the reaction while stirring the dispersion. The stirring speed is not particularly limited, and varies depending on the heating temperature, reaction scale, porogen, amount of surfactant used, etc., for example, 10 to 20,000 rpm, 30 to 10,000 rpm, 50 to 5,000 rpm, 50 to 800 rpm, or 100 to 400 rpm. “Rpm” represents the number of rotations per minute. The stirring speed affects, for example, the particle size of the obtained porous particles. In general, when the stirring speed is high, the particle diameter of the obtained porous particles tends to be small, and when the stirring speed is low, the particle diameter of the porous particles obtained tends to be large. When the stirring speed is moderately high, phase separation or the like can be suppressed and a uniform particle size can be obtained. When the stirring speed is moderately low, the particle diameter does not become too small, and foaming can be suppressed.

  When the polymerization step is completed, as described above, the porogen, the solvent, the unreacted material, and the like are removed from the porous particles as necessary. Specifically, for example, after the dispersion medium containing the porous fine particles is diluted with a large amount of a washing solvent and the precipitated particles are separated by a centrifuge and sufficiently washed, the washing medium is washed with a vacuum dryer. Remove solvent. The washing solvent is preferably a solvent having high solubility in the dispersion medium and porogen, and is preferably a solvent having a low boiling point and easy to remove. Specific examples of the washing solvent include methyl ethyl ketone. In this way, the porous particles of the present invention can be obtained.

  In addition, the produced porous particles may be subjected to surface modification by physical treatment or chemical treatment, for example. The physical treatment or chemical treatment can be performed, for example, for the purpose of improving characteristics as a separation agent for chromatography. Examples of the physical treatment or chemical treatment include surface hydrophilization, surface hydrophobization, and functional group introduction.

  The use of the porous particles of the present invention is not particularly limited, but for example, it is very useful as a novel adsorptive separation agent. More specifically, the porous particles of the present invention can be used, for example, as a separation agent for chromatography. Examples of the separation object of the chromatography include separation of biologically related substances such as proteins, peptides, amino acids, and nucleic acids, and other chemical substances. In addition, the use of the porous particles of the present invention is not limited to this. For example, a column carrying a cosmetic filler, a tire filler, a paint / ink filler, a sustained-release drug base, and a reaction catalyst. It can be used for various applications such as reactor fillers, bactericides, and battery separators. In the case of a battery separator, for example, the porous particles of the present invention can be coated on the surface of an electrode to form a battery separator.

  Examples of the present invention will be described below. However, the present invention is not limited to the following examples.

<Synthesis Example: Synthesis of AB Block Copolymer (Dispersant)>
The AB block copolymer (dispersant) formed from the hydrophobic polymer block A and the hydrophilic polymer block B was produced (synthesized) as in Synthesis Examples 1 and 2 below. In these block copolymers, the constituent monomers are all (meth) acrylate monomers, the polymer chain of the A chain is (meth) acrylate having a hydrophobic group, and the polymer block of the B chain has a hydrophilic group ( The component is (meth) acrylate. Moreover, the number average molecular weight of polystyrene conversion in GPC is 2,000-100,000, the PDI is 1.6 or less, and the number average molecular weight of the polymer block of A composed of (meth) acrylate having a hydrophobic group Is less than 80,000 and 20 to 95% by mass of the total components. In the following, the number of parts of each substance is part by mass (parts by weight) unless otherwise specified.

[Synthesis Example 1]
In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introduction tube, 5.23 parts of toluene, 5 parts of lauryl methacrylate (hereinafter abbreviated as LMA), 0.0495 parts of iodine, and 2,2 as a polymerization initiator '-Azobis (4-methoxy-2,4-dimethylvaleronitrile) (hereinafter abbreviated as V-70) 0.909 parts, Azobisdimethylisovaleronitrile (hereinafter abbreviated as V-65) 0.0183 parts, Then, 0.0726 part of tetrabutylammonium iodide (hereinafter abbreviated as BNI) was charged and stirred at 60 ° C. while flowing nitrogen. Polymerization was carried out for 16 hours to obtain a polymer block A. This was sampled, the solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 90%. The number average molecular weight (hereinafter abbreviated as RI-Mn) of the differential refractometer of GPC at this time was 16,500, and PDI was 1.27.

  Next, 2.33 parts of toluene, 9.34 parts of polyethylene glycol methacrylate (hereinafter abbreviated as PEGMA), 0.121 parts of V-70 were added, and further polymerized at 60 ° C. for 3 hours to obtain B The number average molecular weight of the B chain was 2,100, the PDI was 1.28, and the polymerization conversion was 87%. In this way, a solution of AB block copolymer was obtained. This polymerization solution was dissolved in approximately the same weight of tetrahydrofuran, precipitated in a large amount of methanol and allowed to stand for a while, after which the supernatant was removed and centrifuged. Thereafter, the obtained precipitate was similarly dissolved twice in tetrahydrofuran and precipitated in methanol twice, and then the obtained precipitate was dried to form a semi-liquid AB block copolymer (dispersant). Got. The yield was 41%. The number average molecular weight of the obtained AB block copolymer was 18,700, and PDI was 1.27. Hereinafter, the block copolymer (dispersant) of this synthesis example (synthesis example 1) obtained in this manner is referred to as “block copolymer K-1”.

[Synthesis Example 2]
In a reactor equipped with a stirrer, reflux condenser, thermometer and nitrogen introduction tube, 33.4 parts of dimethyldiglycol (hereinafter abbreviated as DMDG), 100 parts of LMA, 1.5 parts of iodine, tetrabutylammonium iodide (hereinafter referred to as “DMDG”) , BNI) 0.7 part, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (trade name: V-70, manufactured by Wako Pure Chemical Industries, Ltd.) 3.8 as a polymerization initiator Part, 2,2′-azobis (2,4-dimethylvaleronitrile) (trade name: V-65, manufactured by Wako Pure Chemical Industries, Ltd.) 1.0 part was added. And it stirred, introducing argon gas, and heated up at 60 degreeC with the mantle heater. The reaction system was kept at 60 ° C. as it was, and polymerized for 3 hours to obtain a polymer block A. When the progress of the polymerization was calculated by ¹ H-NMR measurement in the reaction system, the polymerization rate was 89%. The molecular weight was calculated by gel permeation chromatography (GPC) measurement (detector: suggested refractometer) using a THF solvent, the number average molecular weight (hereinafter abbreviated as Mn) was 5900, the weight average molecular weight (hereinafter referred to as Mw) It was 8200. Its molecular weight distribution (hereinafter abbreviated as PDI value) was 1.40.

Subsequently, 147 parts of PEGMA, 0.7 part of V-65, and 49 parts of DMDG were added to the reaction system, followed by polymerization at 60 ° C. for 1 hour to form polymer block B. As a result of calculating the progress of polymerization by ¹ H-NMR measurement, the polymerization rate of PEGMA was 23%. Moreover, when the molecular weight was measured by GPC, Mn of the whole block copolymer was 9700, and Mw was 12000. The PDI value was 1.24.

  337 parts of the polymerization solution obtained as described above was diluted with approximately the same amount of THF, washed with saturated saline to remove DMDG and unreacted PEGMA, dried over sodium sulfate, concentrated, and dried at 80 ° C. As a result, 118 parts of a polymer additive comprising an AB block copolymer was obtained. In addition, when DMDG and unreacted PEGMA could not be removed by the washing operation, dialysis (dialysis membrane: Spectra / pore 6, MWCO 1,000) was used in water, and then freeze-dried. Hereinafter, the block copolymer (dispersant) of this synthesis example (synthesis example 2) thus obtained is referred to as “block copolymer K-2”.

  In the following examples, the porous particles of the present invention were produced.

[Example 1]
<Preparation of silica monomer composition>
In a 50 ml beaker, 1.12 g of polyethylene oxide (abbreviation: PEO, weight average molecular weight 10,000) as porogen and 10 mL of 0.01 M acetic acid were added and dissolved with a stirrer chip. After dissolution, cool with ice water and stir while stirring, add 4.5 ml of tetramethoxysilane (abbreviation: TMOS) and stir until it becomes a transparent homogeneous solution (about 15 minutes), and confirm that it has become transparent (hydrolysis) Complete).

<Dispersion preparation process>
In a cylindrical glass sample bottle (with an inner diameter of 19 mm and a height of 60 mm), 0.9 g of the AB block copolymer (dispersant) K-1 was dissolved in 15 g of dodecane as a dispersion medium, and the silica mixture was added. In addition, a dispersion was prepared.

<Polymerization process and post-treatment>
The dispersion was stirred for 10 minutes at 2000 revolutions per minute at room temperature with a stirring blade, and then the polymerization was carried out by reducing the number of revolutions per minute to 50 revolutions and reacting at a temperature of 40 ° C. for 90 minutes in a hot bath. As a result, the silica composition dispersed in the form of fine particles was solidified in the form of particles. The product obtained by this polymerization step was put in MEK and stirred sufficiently, and then the particles were separated using a centrifuge. This washing step with MEK was repeated 10 times to sufficiently remove porogens and residual monomers, and then dried under reduced pressure to obtain 2.6 g of spherical porous particles made of silica gel. The average particle diameter of the porous particles was 12 μm. Moreover, the external appearance of the said spherical porous particle (spherical fine particle) and the SEM photograph of particle | grain surface were shown to FIGS. 1 to 4 show photographs of the particle surface of this example, respectively. Each figure is a photograph with a magnification of 100 times, 1000 times, 5000 times, and 10000 times, respectively. As shown in each of FIGS. 1 to 4, this silica gel porous particle has a through hole in which a porous structure is communicated, and has no skin layer on the surface, and has an end of the through hole. The part opened toward the outside of the porous particles.

[Example 2]
2.6 g of spherical porous particles made of silica gel were obtained in the same manner as in Example 1 except that the block copolymer K-2 was used in place of the block copolymer K-1. The average particle diameter of the porous particles was 11 μm. Moreover, the external appearance of the said spherical porous particle (spherical fine particle) and the SEM photograph of the particle | grain surface and particle | grain inside showed the result similar to FIGS. 1-4 (Example 1). That is, this epoxy resin porous particle had a through-hole in which a porous structure communicated. Moreover, there was no skin layer on the surface of the silica gel porous particles, and the end portions of the through holes opened toward the outside of the porous particles.

Example 3
A spherical porous material made of silica gel in the same manner as in Example 1 except that the nonionic surfactant “Unilube 10MS-250KB” (trade name of NOF Corporation) is used as a dispersant instead of the block copolymer K-1. 3.3g of particles were obtained. The average particle diameter of the porous particles was 12 μm. Moreover, the external appearance of the said spherical porous particle (spherical fine particle) and the SEM photograph of the particle | grain surface and particle | grain inside showed the result similar to FIGS. 1-4 (Example 1). That is, this epoxy resin porous particle had a through-hole in which a porous structure communicated. Moreover, there was no skin layer on the surface of the silica gel porous particles, and the end portions of the through holes opened toward the outside of the porous particles.

  The data of Examples 1 to 3 are shown in Table 1 below.

  Furthermore, when the porous particles of Examples 1 to 3 were used as a separation agent for chromatography, good separation characteristics could be obtained.

  As described above, according to the present invention, there are provided porous silica gel particles having through-holes, having a uniform shape and not blocking the through-holes, a method for producing the same, and a block copolymer used for the method. be able to. The use of the porous particles of the present invention is not particularly limited, but for example, it is very useful as a novel adsorptive separation agent. More specifically, the porous particles of the present invention can be used, for example, as a separation agent for chromatography. Examples of the separation object of the chromatography include separation of biologically related substances such as proteins, peptides, amino acids, and nucleic acids, and other chemical substances. In addition, the use of the porous particles of the present invention is not limited to this. For example, a column carrying a cosmetic filler, a tire filler, a paint / ink filler, a sustained-release drug base, and a reaction catalyst. It can be used for various applications such as a reactor filler.

Claims (11)

Substantially spherical porous particles,
The porous particle is formed of silica gel, and has a through hole in which a porous structure communicates, and an end portion of the through hole opens toward the outside of the porous particle. Porous particles characterized by   The porous particle according to claim 1, wherein the through hole is a through hole formed by spinodal decomposition. The porous particle according to claim 1 or 2, wherein a major axis is 1.6 times or less of a minor axis.   The porous particle according to any one of claims 1 to 3, wherein an average particle diameter is in a range of 0.5 to 30,000 µm. A dispersion preparing step of preparing a dispersion by dispersing a porous particle raw material containing at least one of a silica monomer and a silica prepolymer in a dispersion medium;
A polymerization step of polymerizing the porous particle raw material in the dispersion,
The manufacturing method of the porous particle as described in any one of Claim 1 to 4 which forms the said through-hole by spinodal decomposition | disassembly in the said superposition | polymerization process.   The production method according to claim 5, wherein in the dispersion liquid preparing step, the porous particle material is dispersed in a dispersion medium together with a dispersant.   The production method according to claim 6, wherein the dispersant is a block copolymer formed by including a hydrophobic polymer block and a hydrophilic polymer block. Furthermore, a dispersant production process for producing the dispersant is included,
A first living radical polymerization step in which the dispersant production step forms one of the hydrophobic polymer block and the hydrophilic polymer block by living radical polymerization;
The manufacturing method of Claim 7 including the 2nd living radical polymerization process of forming the other of the said hydrophobic polymer block and a hydrophilic polymer block by living radical polymerization after the said 1st living radical polymerization process.   The production method according to claim 6, wherein the dispersant is a surfactant.   The production method according to claim 9, wherein the surfactant is a nonionic surfactant.   A block copolymer formed by including a hydrophobic polymer block and a hydrophilic polymer block, which is used as the dispersant in the production method according to claim 7 or 8.