JP2017197684A - Crosslinked acrylic organic fine particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic particle that has a plurality of surface regions, and has both of sufficient solvent resistance and heat resistance without metal coordination.SOLUTION: An organic particle is a crosslinked acrylic organic fine particle of which the particle surface is partitioned into two or more regions. Preferably, the fine particle does not contain a transition metal, and preferably, the fine particle contains a crosslinkable monomer-derived structural unit. The crosslinkable monomer-derived structural unit is, for example, 1-70 mass% in the organic fine particle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to crosslinked acrylic organic fine particles having a plurality of surface regions.

  Janus particles are known as particles having a particle surface partitioned into a plurality of regions (Patent Documents 1 to 3, etc.). Janus is a god with two faces that appears in Roman mythology, and Janus particles refer to particles with multiple faces.

  Patent Document 1 discloses particles in which a modified portion in which a material is electrochemically deposited and a non-modified portion are formed on the surface of electrically conductive base particles. However, in the method described in this document, it is necessary to deposit an inorganic component as an electrochemical material, and it is difficult to control the site of electrical deposition and it is difficult to manufacture.

  In Patent Document 2, an organic solvent solution containing two kinds of polymers is dispersed, droplets having two surface regions made of materials containing different polymers are obtained, and two-region fine particles are produced by removing the solvent. It is disclosed that it can be done. However, in the method of Patent Document 2, separation into two types of polymer regions in a droplet (so-called microphase separation) is used as a driving force for forming the two regions. Therefore, it is necessary to dissolve two different types of polymers in an organic solvent, so that a crosslinked structure cannot be introduced into the polymer. Therefore, the particles obtained from the method of Patent Document 2 have insufficient strength, and it is difficult to maintain the particle shape.

  In Patent Document 3, an organic material having two or more kinds of components such as a block copolymer as a molecule is phase-separated (that is, separated for each aggregate phase of the block portion) and coordinated to one phase (block aggregate phase). Inorganic-organic hybrid particles have been disclosed in which a specific metal is coordinated there by allowing a child to exist. However, in this method, the presence of a specific metal is indispensable for sorting the surface, and it cannot be applied to non-metallic materials containing only organic components. In addition, as in Patent Document 2, it does not have a crosslinked structure, and is insufficient in strength to maintain the particle shape in applications requiring the presence of an organic solvent or heat resistance.

Special table 2014-508215 gazette JP 2006-225525 A JP 2010-185023 A

  The present invention has been made paying attention to the circumstances as described above, and its purpose is to have a plurality of surface regions and to have sufficient solvent resistance and heat resistance without coordinating metal. The purpose is to establish a technology that can provide organic particles.

The inventors of the present invention have made extensive studies to solve the above problems. As a result, if the particles are acrylic organic particles, metal coordination becomes unnecessary and the surface is cross-linked to two or more regions. It was found that partitioning provides sufficient solvent resistance and heat resistance, thereby completing the present invention. The present invention is as follows.
(1) Crosslinked acrylic organic fine particles in which the particle surface is partitioned into two or more regions.
(2) The crosslinked acrylic organic fine particles according to (1), which do not contain a transition metal.
(3) The crosslinked acrylic organic fine particles according to the above (1) or (2) having a structural unit derived from a crosslinkable monomer.
(4) The crosslinked acrylic organic fine particles according to any one of (1) to (3), wherein the structural unit derived from the crosslinkable monomer is more than 0 mass% and not more than 80 mass% in the organic fine particles.
(5) The crosslinked acrylic organic fine particles according to any one of (1) to (4), which are a copolymer of these monomers, each having a monofunctional (meth) acrylate monomer unit and a monofunctional styrene monomer unit. .
(6) The crosslinked acrylic organic fine particles according to any one of (1) to (5), wherein the volume average particle diameter is 0.1 to 30 μm.
(7) The above (1) to (6), wherein a monofunctional (meth) acrylate monomer, a crosslinkable monomer, a polymerization initiator, a polymerization inhibitor, and a hydrocarbon organic solvent are mixed in water and suspended or emulsion polymerized. A method for producing a crosslinked acrylic organic fine particle according to any one of the above.

  ADVANTAGE OF THE INVENTION According to this invention, the organic particle excellent in the intensity | strength which has several surface area | region can be provided, without making a metal coordinate.

FIG. 1 is a schematic perspective view showing an example of the organic fine particles of the present invention. FIG. 2 is a schematic instruction showing another example of the organic fine particles of the present invention. FIG. 3 is a first example of a scanning electron micrograph (magnification 8,500 times) of the organic fine particles 3 obtained in the example. FIG. 4 is a second example of a scanning electron micrograph (magnification of 6,000 times) of the organic fine particles 3 obtained in the example. FIG. 5 is a third example of a scanning electron micrograph (magnification: 8,000 times) of the organic fine particles 3 obtained in the example. FIG. 6 is a scanning electron micrograph (magnification 8,500 times) of the organic fine particles 4 obtained in the example.

(1) Organic fine particles The organic fine particles of the present invention do not require a synthesis method using a metal compound or an inorganic compound or a step of dissolving a polymer in an organic solvent, and are synthesized by a polymerization reaction from a monomer. This is characterized in that the particle surface is divided into two or more regions. By having a plurality of regions on the surface, different individualities can be imparted to one particle, and the application range of the particles can be expanded according to the individuality.

  FIG. 1 is a schematic perspective view showing an example of the organic fine particles of the present invention. The organic fine particles 1 in FIG. 1 are partitioned into a first region 11 and a second region 12 having different appearances. One boundary line 21 that separates both regions 11 and 12 is present on the particle surface, and this boundary line 21 has an endless or closed ring shape.

  The number of regions with different appearances may be greater than two. FIG. 2 is a schematic perspective view showing the organic fine particle 1 having three regions of the first region 11, the second region 12, and the third region 13. In the illustrated organic fine particle 1, there are two boundary lines 21 and 22 for sorting each region, and both boundary lines do not intersect with each other and are each independently endless or closed.

  The upper limit of the number of regions is not particularly limited, but is, for example, 4 or less, preferably 3 or less, and the number of regions is most preferably 2. The number of boundary lines may be the same as the number of regions, but is preferably one less than the number of regions. Moreover, although each boundary line may have a common point mutually, it is preferable not to have a common point and to be independent.

  The organic fine particles of the present invention may be an aggregate. This is because particles are rarely handled one by one and are usually handled as aggregates. When viewed as an aggregate, the organic fine particles of the present invention partially include particles having a number of regions less than 2 (that is, no region division) as long as they include fine particles having two or more regions. Also good. The proportion of particles having no region segment is 50% or less (number basis), preferably 30% or less (number basis), more preferably 10% or less (number basis) in the organic fine particles. The proportion of particles can be determined by observing with a scanning electron microscope.

  The size of the minimum region is, for example, 10 area% or more, preferably 15 area% or more in the entire particle surface. The maximum value of the size of the minimum region is a quotient obtained by dividing 100 area% by the number of regions. For example, when the number of regions is 2, the size of the minimum region is 50 area% or less.

  The regions for sorting the surfaces of the organic fine particles of the present invention have different appearances in the above-described illustrated example, but the appearances may not be different. Even if the appearance is not different, it is possible to divide into each region by the presence of an endless or closed annular boundary line, and the present invention also includes particles of such an aspect. Whether the appearance is different can be determined, for example, by whether the surface roughness looks different when the surface of the fine particle is observed with a scanning electron microscope.

  The shape of the organic fine particles of the present invention is not particularly limited, and is a sphere, an ellipsoid (rugby ball type), a shape in which two or more spheres or ellipsoids are combined, and a shape in which a part of each of the shapes is depressed or deleted. The shape may be any of a shape in which a part or all of each shape is contracted, but is preferably a sphere or an ellipsoid (rugby ball type), more preferably a sphere.

The volume average particle diameter of the organic fine particles of the present invention is, for example, 0.1 μm or more, preferably 1 μm or more, for example, 30 μm or less, preferably 20 μm or less.
The coefficient of variation of the volume average particle diameter is, for example, 10% or more, preferably 15% or more, more preferably 20% or more, for example, 60% or less, preferably 55% or less, more preferably 50% or less. is there.

  The organic fine particle of the present invention is a copolymer having a monofunctional (meth) acrylate monomer unit and a crosslinkable monomer unit. Monofunctional (meth) acrylate monomers include (meth) acrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t -Monoalkyl (meth) acrylates such as butyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate; tetrahydrofurfuryl (meth) acrylate, etc. Monocyclic ether-containing (meth) acrylates, and the like. These monofunctional (meth) acrylate monomers can be used alone or in combination of two or more.

As the monofunctional (meth) acrylate monomer, monoalkyl (meth) acrylates are preferable, C _1-4 alkyl (meth) acrylate is more preferable, and methyl (meth) acrylate is particularly preferable. The monofunctional (meth) acrylate monomer is preferably a monofunctional methacrylic monomer.

  The structural unit derived from the monofunctional (meth) acrylate monomer is, for example, 5% by mass or more, preferably 10% by mass or more, more preferably 20% by mass or more in the organic fine particles, for example, less than 100% by mass, Preferably it is 95 mass% or less, More preferably, it is 90 mass% or less, More preferably, it is 65 mass% or less, Most preferably, it is 55 mass% or less.

  Examples of the crosslinkable monomer include monomers having two or more ethylenic carbon-carbon double bonds in one molecule, and the number of ethylenic carbon-carbon double bonds is preferably 2 to 6, The number is more preferably 2 to 3, particularly preferably 2.

  The ethylenic carbon-carbon double bond is preferably contained as a vinyl group (ethenyl group) or (meth) acryloyl group in the crosslinkable monomer, and more preferably as a (meth) acryloyl group. Preferably, it is contained as a methacryloyl group.

  In addition, two or more ethylenic carbon-carbon double bonds are a crosslinkable monomer such as a cyclic group such as an aromatic hydrocarbon ring; a chain group such as a chain hydrocarbon chain or a polyalkyleneoxy group; Bonding via a linking group is preferred. When an ethylenic carbon-carbon double bond is contained as a (meth) acryloyl group, a (meth) acryloyloxy group in which an oxygen atom is further bonded to the (meth) acryloyl group is preferably bonded to the linking group. .

  Examples of the crosslinkable monomer as described above include crosslinkable (meth) acrylate monomers; crosslinkable aromatic monomers such as divinylbenzene, divinylnaphthalene, and N, N-divinylaniline (preferably a crosslinkable styrene monomer). A heteroatom-containing crosslinking agent such as divinyl ether, divinyl sulfide, divinyl sulfonic acid and the like, and a crosslinkable (meth) acrylate monomer is preferable.

  As the crosslinkable (meth) acrylate monomer, a compound in which a (meth) acryloyl group is bonded by forming an ester bond with a diol compound such as alkylene glycol; a triol compound; a polyol compound such as a tetraol compound is preferable. As the polyol compound, alkylene glycols such as ethylene glycol, butanediol, hexanediol, and nonanediol are preferable, and ethylene glycol is particularly preferable.

  The crosslinkable (meth) acrylate monomer may be any of trifunctional monomer, tetrafunctional monomer, pentafunctional monomer, hexafunctional monomer and the like as long as it is bifunctional or higher. Specific examples of the bifunctional crosslinkable (meth) acrylate monomer include ethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, Alkanediol di (meth) acrylates such as 1,9-nonanediol di (meth) acrylate; Alkene (meth) acrylates such as 1,3-butylene di (meth) acrylate; Polyethylene glycol di (meth) acrylate (of ethylene glycol units) Examples of the number of repetitions include 2 to 150); Examples of the trifunctional crosslinkable (meth) acrylate monomer include trimethylolpropane tri (meth) acrylate, and examples of the tetrafunctional crosslinkable (meth) acrylate monomer include pentaerythritol tetra (meth) acrylate. Examples of the hexafunctional crosslinkable (meth) acrylate monomer include dipentaerythritol hexa (meth) acrylate. These crosslinkable (meth) acrylate monomers can be used alone or in combination of two or more. Especially, as a crosslinkable (meth) acrylate type monomer, a 2-6 functional crosslinkable (meth) acrylate type monomer is preferable, More preferably, it is a 2-4 functional crosslinkable (meth) acrylate type monomer, More preferably, 2 It is a functional crosslinkable (meth) acrylate monomer, and alkanediol di (meth) acrylate is particularly preferred. The (meth) acryloyl group is preferably a methacryloyl group.

  The structural unit derived from the crosslinkable monomer is, for example, 0.1 part by mass or more, preferably 1 part by mass or more, and more preferably 10 parts by mass with respect to 100 parts by mass of the structural unit derived from the monofunctional (meth) acrylate monomer. For example, it is 2000 parts by mass or less, preferably 1500 parts by mass or less, and more preferably 1000 parts by mass or less.

  The structural unit derived from the crosslinkable monomer is, for example, more than 0% by mass in the organic fine particles, preferably 0.1% by mass or more, more preferably 1% by mass or more, further preferably 5% by mass or more, particularly Preferably it is 10 mass% or more, for example, 80 mass% or less, Preferably it is 70 mass% or less, More preferably, it is 60 mass% or less.

  The total of the structural unit derived from the monofunctional (meth) acrylate monomer and the structural unit derived from the crosslinkable monomer is 100% by mass, for example, 1% by mass or more, preferably 5% by mass, derived from all monomers. Or more, more preferably 10% by mass or more, further preferably 30% by mass or more, particularly preferably 40% by mass or more, for example, less than 100% by mass, preferably 95% by mass or less, more preferably 90% by mass or less. is there.

  The organic fine particles of the present invention are preferably a copolymer obtained by copolymerizing the monofunctional (meth) acrylate monomer with another monofunctional monomer, and particularly preferably a random copolymer. According to the present invention, the particle surface can be partitioned into two or more regions without using a block copolymer, and such particles can be easily produced.

  Examples of the other copolymerizable monofunctional monomers include styrene monomers; olefin monomers such as ethylene, propylene, butylene; vinyl halide monomers such as vinyl chloride; carboxylic acid vinyl ester monomers such as vinyl acetate; acrylonitrile, etc. (Meth) acrylamide monomers such as (meth) acrylamide; N-vinylpyrrolidone; polybutadiene and the like, and styrene monomers are preferred.

  Examples of the styrenic monomer include styrene; α-substituted styrene such as α-methylstyrene; alkyl styrene such as o-methylstyrene, m-methylstyrene, p-methylstyrene, ethylvinylbenzene, and p-tert-butylstyrene; p -Alkoxystyrene such as methoxystyrene; Aryl styrene such as p-phenylstyrene; Halogenated styrene such as o-chlorostyrene, m-chlorostyrene, p-chlorostyrene; etc. it can. Among these, styrene, alkyl styrene, and halogenated styrene are preferable, and styrene is particularly preferable.

  The other copolymerizable monofunctional monomer is, for example, 0.1 part by mass or more, preferably 1 part by mass or more, more preferably 10 parts by mass or more, further with respect to 100 parts by mass of the monofunctional (meth) acrylate monomer. Preferably it is 75 parts by mass or more, particularly preferably 90 parts by mass or more, for example, 2000 parts by mass or less, preferably 1500 parts by mass or less, more preferably 1000 parts by mass or less, further preferably 500 parts by mass or less, particularly preferably. 300 parts by mass or less.

  The structural unit derived from another copolymerizable monofunctional monomer is, for example, more than 0% by mass, preferably 0.1% by mass or more, more preferably 1% by mass or more, and further preferably 5% by mass or more in the organic fine particles. Especially preferably, it is 10 mass% or more, for example, 80 mass% or less, Preferably it is 70 mass% or less, More preferably, it is 60 mass% or less, More preferably, it is 50 mass% or less.

  The copolymer forming the organic fine particles of the present invention may be substantially one type of polymer or a mixture of two or more types of polymers. Here, “substantially one kind of polymer” refers to a group of polymers whose copolymer composition can be considered to be substantially the same, such as a polymer obtained from one copolymerization reaction. Even a collection of different molecular weights as in the case of having one corresponds to one kind of polymer. Even if it is one type of polymer or two or more types of polymers, it is preferable that the proportion of one type of polymer is high. In the case of two or more kinds of polymers, the maximum proportion of the polymer is, for example, 60% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more in the entire copolymer. According to the present invention, even in the case of substantially one kind of polymer, and even in the case where the ratio of one kind of polymer is increased even if two or more kinds of polymers are divided into two or more regions. Substantially without the use of phase separation of the two polymers. Therefore, particles having two or more regions on the surface can be easily produced.

  The organic fine particles of the present invention are preferably excellent in heat resistance. The thermal decomposition starting temperature of the particles is, for example, 250 ° C. or higher, preferably 260 ° C. or higher, more preferably 270 ° C. or higher, for example, 320 ° C. or lower, preferably 310 ° C. or lower, more preferably 300 ° C. or lower.

Further, the fine particles of the present invention are organic fine particles and substantially do not contain a transition metal. Examples of transition metals that are not contained include, for example, simple metals such as Au, Ag, Pt, Pd, Rh, Ir, Ru, Os, and Cu, metal compounds such as CdS, CeSe, CeTe, and ZnS, and metals such as Fe ₂ O _3. Examples thereof include oxides, alloys such as Ag / Au, Au / Pt. The amount of the transition metal in the organic fine particles is, for example, 1000 ppm or less (mass basis), preferably 100 ppm or less (mass basis), more preferably 10 ppm or less (mass basis). In a preferred embodiment, the fine particles of the present invention do not contain metals other than transition metals, for example, alkali metals such as Na and K and alkaline earth metals such as Ca. The amount of the metal other than the transition metal is, for example, 1000 ppm or less (mass basis), preferably 100 ppm or less (mass basis), more preferably 10 ppm or less (mass basis) in the organic fine particles.

(2) Manufacturing method Although details of the mechanism by which two or more regions are formed on the surface of crosslinked acrylic organic fine particles are unknown, monofunctional (meth) acrylate monomers, crosslinkable monomers, polymerization initiators, polymerization prohibition If the agent and the hydrocarbon-based organic solvent are mixed in water and subjected to suspension or emulsion polymerization, fine particles having two or more regions are produced.
The monofunctional (meth) acrylate monomer and the crosslinkable monomer can be used together with other monomers forming the organic fine particles of the present invention. The types and proportions of these other monomers are as described above.

  As the polymerization initiator, a radical polymerization initiator (particularly a thermal polymerization initiator) is preferable. Examples of the polymerization initiator include benzoyl peroxide, lauryl peroxide, octanoyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, cumene hydroperoxide, cyclohexanone peroxide. , T-butyl hydroperoxide, diisopropylbenzene hydroperoxide and the like peroxide polymerization initiators; 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile) 2,2'-azobis (2,3-dimethylbutyronitrile), 2,2'-azobis- (2-methylbutyronitrile), 2,2'-azobis (2,3,3-trimethylbutyro Nitrile), 2,2'-a Bis (2-isopropylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-4-methoxy-2,4-dimethylvaleronitrile), 2- (carbamoylazo) iso Azo compound polymerization initiators such as butyronitrile, 4,4′-azobis (4-cyanovaleric acid), dimethyl 2,2′-azobis (2-methylpropionate) (preferably oil-soluble azo polymerization initiator) Is mentioned. Among these, an azo compound polymerization initiator is preferable.

  The polymerization initiator is, for example, 0.1 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, for example, 10 parts by mass or less, with respect to 100 parts by mass of all monomers. , Preferably 5 parts by mass or less, more preferably 3 parts by mass or less.

  Examples of the polymerization inhibitor include hydroquinone polymerization inhibitors such as hydroquinone, methylhydroquinone, trimethylhydroquinone, and t-butylhydroquinone; bis (2,2,6,6-tetramethylpiperidinoxy-4-yl) sebacate ( EC3314A), N-oxyl compound polymerization inhibitors such as 4-hydroxy-2,2,6,6-tetramethylpiperidyl-1-oxyl (4H-TEMPO); N-nitrosophenylhydroxyamine ammonium salt (cuperon), etc. N-nitroso compound-based polymerization inhibitors; organic acid copper salts, phenothiazines and the like. N-oxyl compound polymerization inhibitors are particularly useful for forming two or more regions on the particle surface.

  The polymerization inhibitor is, for example, 1 part by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, for example, 80 parts by mass or less, preferably 60 parts by mass with respect to 100 parts by mass of the polymerization initiator. Part or less, more preferably 40 parts by weight or less.

  Examples of hydrocarbon organic solvents include pentane, 2-methylbutane, hexane, 2-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, heptane, octane, 2,2,3-trimethylpentane, isooctane, Non-aliphatic saturated hydrocarbon solvents such as nonane, 2,2,5-trimethylhexane, decane and dodecane, cycloaliphatic carbonization such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, p-menthane and decalin Examples include hydrogen solvents, aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, cumene, mesitylene, tetralin, butylbenzene, p-cymene, diethylbenzene, and pentylbenzene, and these are one or more. Can be used. Preferred are aliphatic saturated hydrocarbon solvents, more preferred are aliphatic saturated hydrocarbon solvents having about 5 to 10 carbon atoms, and particularly preferred are about 5 to 7 carbon atoms.

  The amount of the hydrocarbon-based organic solvent is, for example, 1 part by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, for example, 100 parts by mass or less, preferably 100 parts by mass of all monomers. Is 80 parts by mass or less, more preferably 60 parts by mass or less, and still more preferably 40 parts by mass or less.

The hydrocarbon organic solvent may be used in combination with other solvents. Other solvents include alcohol solvents such as methanol, ethanol, n-propanol, 2-propanol, n-butanol, 2-butanol, 2-methylpropyl alcohol, 2-methyl-2-propanol; ethylene glycol, diethylene glycol, tri Glycol solvents such as ethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, hexanediol and pentanediol; triol solvents such as glycerin and hexanetriol; ether solvents such as tetrahydrofuran; ester solvents such as butyl acetate; acetone, methyl ethyl ketone, etc. Ketone solvent; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol Glycols such as nomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether Ether solvent; glycol ether acetate solvent such as ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate; ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, ethylenediamine, diethylenediamine, Amine solvents such as ethylenetetramine, tetraethylenepentamine, pentamethyldiethylenetriamine, tetramethylpropylenediamine; amide solvents such as formamide, N, N-dimethylformamide, N, N-dimethylacetamide; nitrile solvents such as acetonitrile; dimethyl sulfoxide, etc. Sulfon solvents such as sulfolane; 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, morpholine, N-ethylmorpholine, etc. Ring solvent; and the like. These solvents can be used alone or in combination of two or more.
The proportion of the hydrocarbon-based organic solvent in 100% by mass of the total solvent excluding water is, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, even if it is 100% by mass. Good.

  In the suspension polymerization or emulsion polymerization, a surfactant is preferably used. Examples of the surfactant include an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant, and these may be used alone or in appropriate combination.

  Examples of the anionic surfactant include fatty acid salts such as sodium oleate and potassium castor oil; alkyl sulfate salts such as sodium lauryl sulfate and ammonium lauryl sulfate; alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate; alkylnaphthalene sulfone. Alkane sulfonate; Dialkyl sulfosuccinate; Alkyl phosphate ester salt; Naphthalene sulfonic acid formalin condensate; Polyoxyalkylene alkyl ether sulfate such as polyoxyethylene alkyl ether sulfate; Polyoxyethylene phenyl ether sulfate Salts, polyoxyalkylene aryl ether sulfates such as polyoxyethylene distyryl phenyl ether sulfates; Polyoxyalkylene alkyl sulfate salts such as ether salt; and the like.

  Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate; quaternary ammonium salts such as lauryltrimethylalkylammonium chloride.

Nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester. And oxyethylene-oxypropylene block copolymer.
The amphoteric surfactant is, for example, lauryl dimethylamine oxide.

  Among these, anionic surfactants are preferable from the viewpoint of good polymerization stability and suspension stability, and polyoxyalkylene aryl ether sulfates and polyoxyalkylene alkyl ether sulfates are more preferable.

  The amount of the surfactant is, for example, 0.1 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, for example, 20 parts by mass or less, with respect to 100 parts by mass of all monomers. , Preferably 15 parts by mass or less, more preferably 10 parts by mass or less.

  In the polymerization, if necessary, other additives such as an anti-settling agent, an antifungal agent, an antiseptic, an antioxidant, an ultraviolet absorber, and a light stabilizer may be used.

  The mixing timing of each component can be appropriately set. For example, at least before the polymerization reaction is substantially started (for example, before raising the temperature to the polymerization temperature), at least a monofunctional (meth) acrylate monomer and a crosslinkable monomer are added. The raw material monomer, the polymerization initiator, the polymerization inhibitor, and the hydrocarbon-based organic solvent are preferably allowed to coexist, and more preferably the surfactant is also allowed to coexist. More preferably, raw material monomers including a monofunctional (meth) acrylate monomer and a crosslinkable monomer, a polymerization initiator, a hydrocarbon organic solvent, and a surfactant are strongly stirred or dispersed in water to form oil-in-water droplets. Later, a polymerization inhibitor is added and mixed, and then the temperature is raised to the polymerization temperature to initiate the polymerization.

  Examples of the strong stirring / dispersing device include Milder (manufactured by Ebara Corporation), T.W. K. High-speed shear turbine type dispersers such as homomixers (manufactured by Primix); high-pressure jet homogenizers such as piston type high-pressure homogenizers (manufactured by Gorin) and microfluidizers (manufactured by Microfluidics); ultrasonic homogenizers (Nippon Seiki) Ultrasonic emulsification dispersers such as Seiko Seisakusho; medium stirring dispersers such as Attritor (Mitsui Mining Co., Ltd.); forced gap passing dispersers such as colloid mill (Nihon Seiki Seisakusho) and the like can be used. In addition, you may pre-stir with a normal paddle blade etc. before these strong stirring and dispersion | distribution.

  The stirring speed during strong stirring / dispersion is, for example, T.W. K. When a homomixer is used, 3000 rpm or more is preferable, and 4000 rpm or more is more preferable. The larger the stirring speed, the smaller the diameter of the resulting particles. Moreover, it is preferable that stirring time is 5 to 60 minutes normally. The longer the stirring time, the smaller the particle size and the narrower the particle size distribution. In addition, when the stirring time is within the above range, an increase in the liquid temperature can be prevented and the polymerization reaction can be easily controlled.

  The liquid temperature during strong stirring / dispersion is preferably lower than the polymerization temperature and higher than the solidification temperature of the entire aqueous liquid. For example, it is less than 40 ° C, preferably 35 ° C or less, more preferably 30 ° C or less, for example, -10 ° C or more, preferably 0 ° C or more, more preferably 10 ° C or more.

  The polymerization temperature can be appropriately set according to the type of the polymerization initiator, and is, for example, 40 ° C. or higher, preferably 50 ° C. or higher, more preferably 60 ° C. or higher, for example, 120 ° C. or lower, preferably 110 ° C. or lower. Preferably it is 100 degrees C or less. More suitably, the polymerization is carried out at a temperature, for example, about 5 to 20 ° C. higher than the 10-hour half-life temperature of the polymerization initiator (first stage), and the temperature is further raised to complete the polymerization (second stage). It is preferable. When the polymerization temperature in the first stage is within the above range, the decomposition of the polymerization initiator proceeds moderately, the residual amount of the polymerization initiator in the resulting organic polymer particles is reduced, and the polymerization stability is also good. is there. For example, when the polymerization initiator used is dimethyl 2,2′-azobis (2-methylpropionate) (10 hour half-life temperature: 66 ° C. [in toluene]), the first stage polymerization temperature is 71 to 81. It is preferable to set it as ° C. The polymerization temperature in the second stage is preferably higher by, for example, about 5 to 20 ° C. than the polymerization temperature in the first stage.

  The polymerization time is preferably 5 to 600 minutes, and more preferably 10 to 300 minutes. When the polymerization time is within the above range, the degree of polymerization can be increased moderately and the mechanical properties of the particles can be improved. The polymerization atmosphere is preferably an inert atmosphere such as a nitrogen atmosphere or a rare gas atmosphere.

  The reaction solution containing the obtained fine particles may be concentrated or solid-liquid separated as necessary, and the solvent may be removed (preliminarily dried). Examples of the method for concentration or solid-liquid separation include sedimentation concentration, filtration, centrifugation (decanter), wet sieving, and liquid cyclone. The fine particles separated from the liquid are preferably dried appropriately. At the time of drying, it is dried at a drying temperature of 80 to 100 ° C. (preferably 85 to 95 ° C.) for 10 hours or longer (preferably 12 hours or longer). The dried particles may be agglomerated. Even when agglomerated, it can be pulverized while maintaining the appearance of the particle surface.

  The pulverizing means can be appropriately selected according to the state of aggregation. For example, dry pulverizing means such as a hammer mill, a jet mill, or a bead mill may be used. Examples of the jet mill include a fluidized bed jet mill, an impingement plate jet mill, and a rotary mechanical mill. A fluidized bed jet mill, particularly an airflow jet mill, is preferable. The pulverization pressure in the case of using an airflow type jet mill is, for example, 0.01 MPa or more, preferably 0.05 MPa or more, more preferably 0.1 MPa or more, for example, 3 MPa or less, preferably 1 MPa or less, more preferably 0. .5 MPa or less.

(3) Uses Although the use of the organic fine particles of the present invention is not particularly limited, it is an antiblocking agent or slipperiness imparting agent for various films such as polyolefin films, polyester films, polyimide films, fluororesin films; light diffusion films, light diffusion plates. It is preferably used for a light diffusing agent used for a light guide plate, an antiglare film or the like.

  In any case, the organic fine particles of the present invention can be dispersed in a thermoplastic resin in advance and used as a master batch. The thermoplastic resin used in the masterbatch is preferably the same as the matrix resin for each application.

  The content of the organic fine particles of the present invention in the master batch is, for example, 0.1% by mass or more, preferably 1% by mass or more, more preferably 5% by mass or more, for example, 50% by mass or less, preferably 30%. It is at most 20% by mass, more preferably at most 20% by mass.

  You may mix | blend antioxidants, such as a hindered phenolic antioxidant and phosphorus antioxidant, with the said masterbatch as needed. The amount of the antioxidant in the master batch is, for example, 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, for example, 5% by mass or less, preferably 3% by mass. % Or less, more preferably 2% by mass or less.

  When the organic fine particles of the present invention are used as a light diffusing agent, usually, a coating solution containing the fine particles is applied to a substrate such as a film or a plate to impart light diffusibility. This coating solution usually contains a matrix resin and a solvent. The matrix resin is preferably a thermoplastic resin such as a (meth) acrylic resin or a thermosetting resin, but may be a photocurable resin. As the solvent, aromatic solvents such as toluene; aliphatic hydrocarbon solvents such as hexane and heptane; alcohol solvents; ester solvents; ketone solvents; amide solvents can be used as appropriate.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention. In the following, “part” means “part by mass” and “%” means “mass%” unless otherwise specified.

Evaluation items and evaluation methods of the organic fine particles obtained in the examples are as follows.
(1) Particle size, coefficient of variation (CV value)
Organic fine particles are added to 8 g of ion-exchanged water containing a surfactant (“Haitenol (registered trademark) N-08”, polyoxyalkylene alkylphenyl ether sulfate ammonium salt, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) at a concentration of 1%. 025 g was dispersed, and the particle size of 30,000 organic polymer particles was measured using a precision particle size distribution analyzer (“Coulter Multisizer III” manufactured by Beckman Coulter, Inc., aperture 50 μm). The mass-based average particle diameter and the coefficient of variation of the particle diameter are obtained.
Coefficient of variation of particle diameter (%) = (σ / d50) × 100
Here, σ is the standard deviation of the particle size, and d50 is the mass-based average particle size.

(2) Particle surface structure The surface of the organic fine particles is photographed with a scanning electron microscope (SEM) under conditions of a magnification of 500 to 10,000 and an acceleration voltage of 2 kV. It is confirmed whether the particle surface has two or more regions, and the number of regions is counted.

(3) Thermal decomposition start temperature Using a thermal analyzer (DTG-50M, Shimadzu Corporation), sample amount 15 mg, temperature rising rate 10 ° C./min (maximum temperature reached 500 ° C.), air flow rate 20 mL / min The thermal decomposition start temperature of the organic fine particles is measured under the following conditions. First, using a precision balance, weigh a 15 mg sample in a predetermined aluminum cup, place this aluminum cup in a predetermined position on the thermal analyzer, and adjust it so that air at the specified flow rate (20 mL / min) flows. Then, the temperature rise is started after the state of the apparatus is stabilized. The intersection of the extension line of the base line (horizontal line part) of the TG curve obtained at this time and the tangent line of the mass reduction part (lower oblique line part) is defined as the thermal decomposition start temperature of the organic fine particles.

(4) Master batch applicability 10 parts of organic fine particles, 90 parts of polypropylene pellets (Novatech (registered trademark) FY4, manufactured by Nippon Polypro Co., Ltd.), hindered phenol antioxidant (Irganox (registered trademark) 1010, BASF Corporation) 0.5 parts of phosphorous processing heat stabilizer (Irgafos (registered trademark) 168, manufactured by BASF) 0.5 parts in the same direction rotating twin-screw kneading extruder ((HK-25D) Parker) And the mixture is melt-kneaded at 210 to 220 ° C. and cooled with water to obtain a strand. A polypropylene master batch containing 10% by mass of organic fine particles is prepared by cutting appropriately. The obtained master batch is visually confirmed, and the presence or absence of coloring due to the influence of heating and melting during production is confirmed.

(5) Applicability of light diffusing film-Production of light diffusing film A polyester film having a thickness of 100 µm was prepared by mixing and dispersing 22 parts of an acrylic resin, 27 parts of organic fine particles to be evaluated, and 39 parts of butyl acetate with a disper. A light diffusing film is obtained by applying and drying on the surface of PET Toyobo Cosmo Shine A-4300) using a bar coater.
-Evaluation of light diffusion film As a backlight unit, a backlight unit used in a liquid crystal television "AQUAS LC-37AD" manufactured by Sharp Corporation is used. This backlight unit has a light source and a light diffusion plate. The light diffusing film of each example was placed on the light diffusing plate of this backlight unit, a luminance meter was installed at a position 50 cm away from this light diffusing film, and the front luminance was measured at any nine locations. Evaluate unevenness.
・ Evaluation criteria for luminance unevenness ○: No luminance unevenness △: Slight luminance unevenness ×: Brightness unevenness

Example 1
Raw material mixture adjustment process:
3.6 parts of polyoxyethylene distyryl phenyl ether sulfate ammonium salt (trade name “Hytenol (registered trademark) NF-08”, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was dissolved in 221 parts of deionized water (No. 1 solution). Separately, 54 parts of methyl methacrylate (MMA) as monomer for particle formation, 54 parts of ethylene glycol dimethacrylate (EGDMA), and 72 parts of styrene (St), dimethyl which is an oil-soluble azo polymerization initiator as a polymerization initiator After dissolving 3.6 parts of 2,2′-azobis (2-methylpropionate) (V-601) (2.0% by mass with respect to the total mass of monomers), as an additive (hydrocarbon solvent) 36 parts of n-hexane was added (second solution). Mixing the first solution and the second solution; K. The mixture was stirred for 8 minutes at 4000 rpm with a homogenizer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain a uniform suspension (raw material mixture).

Polymerization process:
The homogeneous suspension (raw material mixture) was transferred to a flask equipped with a stirrer, an inert gas introduction tube, a reflux condenser, a thermometer, and a dropping funnel. An aqueous solution obtained by diluting 0.5 part of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (4H-TEMPO) as a polymerization inhibitor with 450 parts of deionized water was added, and then nitrogen gas Was heated until the reaction solution reached 65 ° C. The reaction vessel was kept warm at 65 ° C, and the temperature rise exceeded 70 ° C due to self-heating, and a peak was confirmed. After confirming the peak of polymerization, the internal temperature of the polymerization solution was adjusted to 75 ° C., and stirring was continued for 1.5 hours at this temperature. Then, the polymerization solution was further heated to 85 ° C. and stirred for 2 hours. Completed. Thereafter, the reaction liquid (suspension) is cooled and filtered to collect a polymerized product, which is dried at 85 ° C. for 15 hours using a hot air dryer (manufactured by Yamato Kagaku Co., Ltd.) to remove organic fine particles. Obtained. Since the organic fine particles were aggregated by drying, Super Jet Mill SJ-500 (manufactured by Nisshin Engineering Co., Ltd.) was used and pulverized at a pulverization pressure of 0.3 MPa at room temperature. Thereby, organic fine particles 1 without aggregation were obtained. The dried organic fine particles after the above pulverization step were spherical, the volume average particle size was 10 μm, and the coefficient of variation was 35%.

Examples 2-7
Organic fine particles 2 to 7 were obtained in the same manner as in Example 1 except that the monomer, initiator, additive, and polymerization inhibitor were changed as shown in Table 1.

Comparative Examples 1-2
Comparative organic fine particles 1 and 2 were obtained in the same manner as in Example 1 except that the monomer, initiator, additive, and polymerization inhibitor were changed as shown in Table 1.

  The organic fine particles 1 to 7 and the comparative organic fine particles 1 to 2 obtained as described above were evaluated from the above viewpoint. The results are shown in Table 2 below and FIGS. 3 to 5 are scanning electron micrographs of the organic fine particles 3 (FIG. 3: magnification of 8,500 times, FIG. 4: 6,000 times, FIG. 5: 8,000 times), and FIG. It is a scanning electron micrograph (magnification 8,500 times). In addition, (a) of each figure shows an electron micrograph as it is, and (b) of each figure clearly shows the boundary between the outer shape of the particle and the region with a white line. As shown in FIGS. 3 to 5, the organic fine particles 3 are a mixture of fine particles having two regions and fine particles having three regions.

1 organic fine particles 11, 12, 13 region 21, 22 boundary line

Claims (7)

  Crosslinked acrylic organic fine particles whose particle surface is partitioned into two or more regions.   The crosslinked acrylic organic fine particles according to claim 1, which do not contain a transition metal.   The crosslinked acrylic organic fine particles according to claim 1 or 2, which have a structural unit derived from a crosslinkable monomer.   The cross-linked acrylic organic fine particles according to any one of claims 1 to 3, wherein the structural unit derived from the cross-linkable monomer is more than 0% by mass and 80% by mass or less in the organic fine particles.   The crosslinked acrylic organic fine particle according to any one of claims 1 to 4, which is a copolymer of these monomers having a monofunctional (meth) acrylate monomer unit and a monofunctional styrene monomer unit.   The cross-linked acrylic organic fine particles according to any one of claims 1 to 5, having a volume average particle diameter of 0.1 to 30 µm.   The monofunctional (meth) acrylate monomer, the crosslinkable monomer, the polymerization initiator, the polymerization inhibitor, and the hydrocarbon organic solvent are mixed in water, and suspended or emulsion polymerized. A method for producing crosslinked acrylic organic fine particles.