Resin microparticles, method for producing the same, and use thereof

Abstract

Resin microparticles with reduced metallic and leached ion content and excellent dielectric properties are provided. Furthermore, a method for manufacturing such resin microparticles is provided. The resin microparticles of embodiments of the present invention have a total content of component A of less than 100 ppm as determined by inductively coupled plasma atomic emission spectrometry, a total content of leached ion component B of less than 100 ppm as determined by ion chromatography, and a dielectric loss tangent of 0.0050° or less at a frequency of 10 GHz. Component A includes Al, Ba, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, P, S, Si, Sr, and Zn. Ionic component B includes fluoride ions, chloride ions, nitrite ions, bromide ions, nitrate ions, phosphate ions, and sulfate ions.

Description

Technical Field

[0001] This invention relates to resin microparticles, methods for their manufacture, and their uses. Background Technology

[0002] Resin microparticles are widely used as anti-blocking agents for light diffusion plates and various films, as modifiers for various films, as spacers between tiny parts of various electronic devices, as pore-forming agents for various battery components, and as core particles for conductive microparticles that provide electrical connections, among other applications.

[0003] In recent years, various studies have been conducted in the semiconductor component market to achieve miniaturization and high performance of electronic circuits. For example, it has been reported that by adding fillers to various semiconductor components such as sealants, interlayer insulating films, and copper-clad laminates, semiconductor components with improved physical properties such as elasticity can be obtained while maintaining good dielectric properties (Patent Document 1). However, when applying resin microparticles to such applications, in order to adapt to the miniaturization of semiconductor components, it is required that the resin microparticles have small particle size, low dielectric loss tangent of the microparticles themselves, and that the metal or ionic components be reduced in advance to prevent ion migration.

[0004] Methods for producing resin microparticles with an average particle size of less than 1 μm include emulsion polymerization and seed polymerization. However, these polymerization methods require the use of large amounts of surfactants when emulsifying oil droplets, resulting in an increase in residual ionic components in the resulting resin microparticles. As a technique to reduce residual ionic components, a cleaning process for washing the particles has been reported (Patent Document 2), but more precise cleaning requires a large amount of cleaning water, which poses problems in terms of production and cost.

[0005] There have been reports of low-ionic resin microparticles manufactured without the use of surfactants and emulsifiers (Patent Document 3). However, the low-ionic resin microparticles described in Patent Document 3 have a high dielectric loss tangent because they have polar groups such as amino groups on their particle surface.

[0006] Hollow particles capable of achieving low dielectric properties in semiconductor components have been reported (Patent Document 4). However, precisely because they are hollow particles, their strength is an issue. Existing technical documents Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2023-165254 Patent Document 2: International Publication No. 2015 / 045448 Patent Document 3: Japanese Patent Application Publication No. 2005-082695 Patent Document 4: Japanese Patent Application Publication No. 2022-117594 Summary of the Invention The problem the invention aims to solve

[0008] This invention was made to solve the aforementioned problems, and its main objective is to provide resin microparticles with reduced metal and dissolved ion content and excellent dielectric properties. Furthermore, it provides a method for manufacturing such resin microparticles. Additionally, it provides uses for such resin microparticles. Technical means for solving problems

[0009] [1] Regarding the resin microparticles in the embodiments of the present invention, The total content of component A, as determined by inductively coupled plasma atomic emission spectrometry, was less than 100 ppm. The total amount of dissolved ion component B, as determined by ion chromatography, was less than 100 ppm. The dielectric loss tangent at a frequency of 10 GHz is below 0.0050°. Component A: Al, Ba, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, P, S, Si, Sr, and Zn Ionic component B: Fluoride ion, chloride ion, nitrite ion, bromide ion, nitrate ion, phosphate ion, and sulfate ion [2] Regarding the resin microparticles described in [1] above, the dielectric loss tangent can be less than 0.0030. [3] Regarding the resin microparticles described in [1] or [2] above, they may comprise polymers (P) obtained by reacting a composition containing a free radical polymerizable monomer component (M). The monomer component (M) mentioned above includes cross-linking monomers (a) and aromatic monofunctional monomers (b). [4] Regarding the resin microparticles described in [3] above, the crosslinking monomer (a) may include aromatic crosslinking monomers. [5] Regarding the resin microparticles described in [3] or [4] above, the composition may contain a reactive surfactant (A). [6] The volume average particle size of the resin microparticles described in any one of [1] to [5] above may be 0.05 μm or more and 2 μm or less. [7] Regarding the resin microparticles mentioned in any one of [1] to [6] above, the proportion of particles with a particle size of 10 μm or more may be less than 0.01% by volume. [8] The resin particles mentioned in any one of [1] to [7] above may be dry powders. [9] The coefficient of variation of the volume average particle size of the resin microparticles described in any one of [1] to [8] above may be less than 25%.

[10] The resin microparticles mentioned in any one of [1] to [9] above can be used as additives for electronic materials.

[11] The resin microparticles mentioned in any one of [1] to [9] above can be used as additives for optical materials.

[12] The resin microparticles mentioned in any one of [1] to [9] above can be used as additives for coatings.

[13] The resin microparticles described in any one of [1] to [9] above can be used as an additive for inks.

[14] The method for manufacturing resin microparticles according to the embodiments of the present invention is as follows: The method for manufacturing resin microparticles as described in any one of [1] to

[13] above, It involves a two-stage polymerization process, including a first polymerization step and a second polymerization step. In the first polymerization step described above, the free radical polymerizable monomer component (M1), containing a monofunctional monomer (b1), is emulsion polymerized. In the second polymerization step described above, a free radical polymerizable monomer component (M2) comprising a monofunctional monomer (b2) and a crosslinking monomer (a) is emulsion polymerized.

[15] In the method for manufacturing resin microparticles described above

[14] , the first polymerization step and the second polymerization step can be carried out in a single reactor.

[16] In the method for manufacturing resin microparticles described in

[14] or

[15] above, a reactive surfactant may be used in at least one step selected from the first polymerization step and the second polymerization step above.

[17] In any of the above-mentioned methods for manufacturing resin microparticles

[14] to

[16] , a water-soluble azo compound may be used as a polymerization initiator in at least one step selected from the above-mentioned first polymerization step and the above-mentioned second polymerization step.

[18] In the method for manufacturing resin microparticles described in any one of

[14] to

[17] above, non-reactive surfactants may not be used in the first polymerization step and the second polymerization step above.

[19] In the method for manufacturing resin microparticles in any one of

[14] to

[18] above, the monofunctional monomer (b2) in the second polymerization step may contain an aromatic monofunctional monomer, and the crosslinking monomer (a) may contain an aromatic crosslinking monomer. Invention Effects

[0010] According to embodiments of the present invention, resin microparticles with reduced metal and dissolved ion content and excellent dielectric properties can be provided. Furthermore, a method for manufacturing such resin microparticles can also be provided. In addition, uses for such resin microparticles can also be provided. Detailed Implementation

[0011] The embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

[0012] In this specification, when the term "(meth)acrylic acid" is used, it means "acrylic acid and / or methacrylic acid"; when the term "(meth)acrylate" is used, it means "acrylate and / or methacrylate"; and when the term "(meth)acrylonitrile" is used, it means "acrylonitrile and / or methacrylonitrile".

[0013] <<<<Resin Microparticles>>>> In the resin microparticles of the embodiments of the present invention, the total content of component A is less than 100 ppm, and the total content of leached ion component B is less than 100 ppm. Component A: Al, Ba, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, P, S, Si, Sr, and Zn Ionic component B: Fluoride ion (F - ), chloride ions (Cl) - ), nitrite ions (NO2) - ), bromide ions (Br) - ), nitrate ions (NO3) - ), phosphate ions (PO4) 3- ) and sulfate ions (SO4) 2- )

[0014] The total content of component A in the resin microparticles was determined by inductively coupled plasma (ICP) emission spectrometry. The total amount of dissolved ionic component B in the resin microparticles was determined by ion chromatography. In this specification, the total content of component A in the resin microparticles refers to the mass of component A per unit mass of resin microparticles, and the total amount of dissolved ionic component B in the resin microparticles refers to the mass of dissolved ionic component B per unit mass of resin microparticles. Therefore, in both the total content of component A and the total amount of dissolved ionic component B, 1 ppm = 1 mg / kg.

[0015] Thus, resin particles with low total content of component A and low total amount of dissolved ion component B will not affect the performance of tiny components even when used, making them particularly suitable for miniaturized semiconductor components. However, if the total content of component A in the resin particles exceeds 100 ppm, component A leached from the resin particles may reduce the performance of components obtained by mixing the resin particles with resins. Similarly, if the total amount of dissolved ion component B in the resin particles exceeds 100 ppm, the ions leached from the resin particles may reduce the performance of components obtained by mixing the resin particles with resins. For example, when resin particles with high total content of component A or high total amount of dissolved ion component B are used in semiconductor components, the leaching of component A and ion component B from the resin particles may lead to ion migration.

[0016] In embodiments of the present invention, the total content of component A in the resin microparticles is preferably 70 ppm or less, more preferably 50 ppm or less, further preferably 30 ppm or less, even more preferably 20 ppm or less, particularly preferably 15 ppm or less, and most preferably 12 ppm or less. The lower limit of the total content of component A in the resin microparticles in embodiments of the present invention is, for example, 0 ppm or more, or 0.1 ppm or more.

[0017] In embodiments of the present invention, the total amount of leached ion component B in the resin microparticles is preferably 100 ppm or less, more preferably 70 ppm or less, even more preferably 50 ppm or less, even more preferably 30 ppm or less, particularly preferably 15 ppm or less, and most preferably 12 ppm or less. The lower limit of the total amount of leached ion component B in the resin microparticles in embodiments of the present invention is, for example, 0 ppm or more, or possibly 0.1 ppm or more.

[0018] The resin microparticles of the embodiments of the present invention have a dielectric loss tangent of 0.0050° or less at a frequency of 10 GHz. Therefore, resin microparticles with a low dielectric loss tangent can enable resins incorporating these microparticles to exhibit excellent dielectric properties. Examples of excellent dielectric properties include, for instance, a low dielectric constant and a low dielectric loss tangent.

[0019] In embodiments of the present invention, the dielectric loss tangent of the resin microparticles at a frequency of 10 GHz is preferably 0.0040° or less, more preferably 0.0030° or less, further preferably 0.0020° or less, particularly preferably 0.0015° or less, and most preferably 0.0010° or less. The lower limit of the above-mentioned dielectric loss tangent is preferably 0° or more.

[0020] The relative permittivity of the resin microparticles in the embodiments of the present invention at a frequency of 10 GHz is preferably 1.0 to 2.5, more preferably 1.0 to 2.4, even more preferably 1.0 to 2.3, and particularly preferably 1.0 to 2.2.

[0021] The volume average particle size (volume average primary particle size) of the resin microparticles in the embodiments of the present invention is not particularly limited and can be appropriately set according to the purpose and application. The volume average particle size of the resin microparticles in the embodiments of the present invention is, for example, 3 μm or less, preferably 2 μm or less, more preferably 1.5 μm or less, and even more preferably 1.0 μm or less. The volume average particle size of the resin microparticles in the embodiments of the present invention is, for example, 0.05 μm or more, preferably 0.07 μm or more, and even more preferably 0.1 μm or more. The volume average particle size of the resin microparticles in the embodiments of the present invention is preferably 0.05 μm or more and 2 μm or less, more preferably 0.08 μm or more and 2 μm or less, and even more preferably 0.1 μm or more and 1 μm or less. Volume average particle size can be determined, for example, using a laser diffraction scattering particle size distribution measuring device manufactured by Beckman Coulter, Inc.

[0022] The coefficient of variation of the volume average particle size of the resin microparticles in the embodiments of the present invention is not particularly limited and can be appropriately set according to the purpose and application. The coefficient of variation of the volume average particle size of the resin microparticles in the embodiments of the present invention is, for example, 40% or less, preferably 30% or less, more preferably 25% or less, and even more preferably 20% or less. The coefficient of variation of the volume average particle size of the resin microparticles in the embodiments of the present invention is, for example, 1% or more, 5% or more, and furthermore, 10% or more. The coefficient of variation of the volume average particle size of resin microparticles is a value calculated by the following formula (1), which represents the distribution width of the data. Coefficient of variation [%] = (Standard deviation of particle size distribution based on volume of resin particles ÷ Volume average particle size of resin particles) × 100 (1)

[0023] In the resin microparticles of the embodiments of the present invention, the proportion of particles with a particle size of 10 μm or more is, for example, 0.01% by volume or less, preferably 0% by volume. As a method for determining the above proportion, the proportion is based on the number of particles, and the method described in the examples described later can be used, for example.

[0024] The resin microparticles in embodiments of the present invention are typically solid particles. The resin microparticles in embodiments of the present invention can be dry powders or dispersed in a liquid (dispersion medium).

[0025] <Polymer P> Typically, the resin microparticles of embodiments of the present invention comprise a polymer (P) obtained by reacting a composition comprising a free radical polymerizable monomer component (M). The monomer component (M) preferably comprises a vinyl monomer, more preferably a crosslinking monomer (a) and an aromatic monofunctional monomer (b). Thus, a preferred embodiment of the polymer (P) has structural units derived from the crosslinking monomer (a) and structural units derived from the aromatic monofunctional monomer (b).

[0026] The polymer (P) can be one type or two or more types.

[0027] From the viewpoint of better realizing the effects of the present invention, the content of polymer (P) in the resin microparticles of the embodiments of the present invention is preferably 60% to 100% by mass, more preferably 70% to 100% by mass, further preferably 80% to 100% by mass, even more preferably 90% to 100% by mass, particularly preferably 95% to 100% by mass, and most preferably 98% to 100% by mass.

[0028] The crosslinking monomer (a) has two or more double bonds within its molecule. Any suitable crosslinking monomer (a) can be used as long as it is a crosslinking monomer (having two or more double bonds within its molecule) without impairing the effects of the present invention. Examples of crosslinking monomers (a) include, for instance, divinylbenzene, divinylnaphthalene, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, decaethylene glycol di(meth)acrylate, pentadecylethylene glycol di(meth)acrylate, heptadecanylethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, allyl(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetraacrylate, neopentyl glycol di(meth)acrylate, etc. From the viewpoint of better realizing the effects of the present invention, the crosslinking monomer (a) is preferably an aromatic crosslinking monomer such as divinylbenzene or divinylnaphthalene, which has an aromatic functional group and two or more free radical polymerizable double bonds in its backbone, and more preferably divinylbenzene. The crosslinking monomer (a) can be used alone or in combination with two or more monomers.

[0029] As an aromatic monofunctional monomer (b), any suitable aromatic monofunctional monomer can be used without impairing the effects of the present invention, as long as it has a molecular structure with an aromatic functional group in its backbone and a double bond that can be polymerized by free radicals. Examples of aromatic monofunctional monomers (b) include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, tert-butylstyrene, ethyl vinylbenzene, vinylnaphthalene, styrene sulfonic acid, styrene sulfonate, vinylbenzoic acid, and vinylphenol. Examples of styrene sulfonates include sodium styrene sulfonate and ammonium styrene sulfonate. Examples of vinylbenzoic acid include o-vinylbenzoic acid, m-vinylbenzoic acid, and p-vinylbenzoic acid. Examples of vinylphenol include o-vinylphenol, m-vinylphenol, and p-vinylphenol. From the viewpoint of better exerting the effects of the present invention, as an aromatic monofunctional monomer (b), it is preferable to select at least one from the group consisting of styrene, α-methylstyrene, tert-butylstyrene, and ethyl vinylbenzene, and more preferably at least one from the group consisting of styrene and ethyl vinylbenzene. These aromatic monofunctional monomers (b) can be used alone or in combination with more than one.

[0030] From the viewpoint of better realizing the effects of the present invention, the total content of the crosslinking monomer (a) and the aromatic monofunctional monomer (b) in the monomer component (M) is preferably 50% to 100% by mass, more preferably 80% to 100% by mass, further preferably 90% to 100% by mass, and particularly preferably 95% to 100% by mass.

[0031] From the viewpoint of better realizing the effects of the present invention, the content of crosslinking monomer (a) in monomer component (M) is preferably 1% to 50% by mass, more preferably 2% to 40% by mass, further preferably 3% to 30% by mass, even more preferably 5% to 25% by mass, particularly preferably 8% to 20% by mass, and most preferably 9% to 18% by mass.

[0032] From the viewpoint of better realizing the effects of the present invention, the content of aromatic monofunctional monomers (b) in the monomer component (M) is preferably 50% to 99% by mass, more preferably 60% to 98% by mass, further preferably 70% to 97% by mass, particularly preferably 75% to 96% by mass, and most preferably 80% to 95% by mass.

[0033] The monomer component (M) may contain any suitable other free radical polymerizable monomer (m) that is different from either the crosslinking monomer (a) or the monofunctional monomer (b) described above, without impairing the effects of the present invention. Therefore, the polymer (P) may have structural units derived from the crosslinking monomer (a), structural units derived from the aromatic monofunctional monomer (b), and structural units derived from other free radical polymerizable monomers (m).

[0034] Other free radical polymerizable monomers (m) include, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, amyl methacrylate, isoamyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, nonyl methacrylate, and methyl propylene. Isononyl acrylate, decyl acrylate, isodecanyl acrylate, undecyl acrylate, dodecyl acrylate, tridecyl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexadecyl acrylate, heptadecanyl acrylate, octadecyl acrylate, isostearyl acrylate, nonadecanyl acrylate, eicosyl acrylate, etc., are alkyl acrylates of (meth)acrylate in which the alkyl group attached to the ester has 1 to 20 carbon atoms; (meth)propane Monomers containing alicyclic structures, such as cyclohexyl acrylate, isobornyl acrylate, and dicyclopentyl acrylate; hydroxyalkyl acrylate monomers, such as hydroxyethyl acrylate; and monomers containing carboxyl groups, such as methacrylic acid, 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl hexahydrophthalic acid, 2-methacryloyloxyethyl maleic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethyl succinic acid, and 2-acryloyloxyethyl phthalic acid. Monomers containing glycidyl groups, such as glycidyl acrylate, allyl glycidyl ether, and 4-hydroxybutyl (meth)acrylate glycidyl ether; monomers containing epoxy groups, such as 1,2-epoxy-4-vinylcyclohexane and (3,4-epoxycyclohexyl) methyl methacrylate; acrylamide derivative monomers, such as 4-vinylphenyl glycidyl ether (meth)acrylamide; (meth)acrylonitrile monomers; halogenated vinyl monomers, such as vinyl chloride; vinyl acetate and other carboxylic acid vinyl ester monomers; olefin monomers, such as ethylene; unsaturated imide monomers; vinyl alcohol; silane coupling agents containing vinyl groups, etc. Other free radical polymerizable monomers (m) may be used in single or multiple forms. The monomer component (M) may also be free of other free radical polymerizable monomers (m).

[0035] From the viewpoint of better realizing the effects of the present invention, the content of other free radical polymerizable monomers (m) in the monomer component (M) is preferably 0% to 50% by mass, more preferably 0% to 20% by mass, further preferably 0% to 10% by mass, particularly preferably 0% to 5% by mass, and most preferably 0% to 2% by mass.

[0036] From the viewpoint of maximizing the effects of the present invention, the monomer component (M) in the composition is preferably 85% to 100% by mass, more preferably 90% or more and less than 100% by mass, further preferably 95% or more and less than 100% by mass, particularly preferably 97% or more and less than 100% by mass, and most preferably 98% to 99% by mass. If the monomer component (M) in the composition is too low or deviates from the above range, the effects of the present invention may not be achieved; for example, excellent dielectric properties may not be exhibited. Here, the monomer component (M) does not include polymerization initiators and surfactants used in the polymerization reaction.

[0037] In addition to the monomer component (M), the composition preferably also contains a reactive surfactant (A). Therefore, the polymer (P) preferably has structural units derived from aromatic monofunctional monomers (b), structural units derived from crosslinking monomers (a), and structural units derived from reactive surfactant (A). It may also have structural units derived from crosslinking monomers (a), structural units derived from aromatic monofunctional monomers (b), structural units derived from other free radical polymerizable monomers (m), and structural units derived from reactive surfactant (A).

[0038] Typically, a reactive surfactant (A) has one or more double bonds within its molecule. Examples of reactive surfactants (A) include anionic reactive surfactants and nonionic reactive surfactants.

[0039] Examples of anionic reactive surfactants include, for instance, ELEMINOL JS-20 or RS-3000 manufactured by Sanyo Chemical Co., Ltd.; Aqualon KH-10, KH-1025, KH-05, HS-10, HS-1025, BC-0515, BC-10, BC-1025, BC-20, BC-2020, AR-1025, or AR-2025 manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.; Antox MS-60 manufactured by Nippon Emulsifier Co., Ltd.; LATEMUL S-120, S-180A, S-180, or PD-104 manufactured by Kao Corporation; and ADEKA REASOAP SR-1025 or SE-10N manufactured by ADEKA Corporation. From the viewpoint of improving the dispersibility of resin particles, anionic reactive surfactants preferably have alkylene oxide chains in their molecular chains.

[0040] Examples of nonionic reactive surfactants include alkyl ethers (commercially available products such as ADEKA REASOAPER-10, ER-20, ER-30, ER-40 manufactured by ADEKA Corporation; LATEMUL PD-420, PD-430, PD-450 manufactured by Kao Corporation); alkyl phenyl ethers or alkyl phenyl esters (commercially available products such as Aqualon RN-10, RN-20, RN-30, RN-50, AN-10, AN-20, AN-30, AN-5065 manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.; ADEKA REASOAPNE-10, NE-20, NE-30, NE-40 manufactured by ADEKA Corporation); and (meth)acrylate sulfates (commercially available products such as RMA-564, RMA-568, RMA-1114 manufactured by Nippon Emulsifier Co., Ltd.). From the perspective of the dispersion stability of resin particles, nonionic reactive surfactants preferably have alkylene oxide chains in their molecular chains.

[0041] From the viewpoint of better realizing the effects of the present invention, when the total amount of monomer components (M) (crosslinking monomer (a), aromatic monofunctional monomer (b), and other free radical polymerizable monomers (m)) is 100 parts by mass, the content of reactive surfactant (A) in the composition is preferably 0 to 10 parts by mass, more preferably more than 0 parts by mass and less than 8 parts by mass, further preferably more than 0 parts by mass and less than 5 parts by mass, particularly preferably more than 0 parts by mass and less than 3 parts by mass, and most preferably 0.1 to 2 parts by mass. If the content is too high and deviates from the above range, the effects of the present invention may not be realized; for example, excellent dielectric properties may not be exhibited. If the content is too low and deviates from the above range, the effects of the present invention may not be realized; for example, the dispersion stability of the particles deteriorates, and resin microparticles cannot be obtained.

[0042] <<<<Uses of Resin Microparticles>>>> The resin microparticles of the embodiments of the present invention can be used for various applications. From the viewpoint of being able to more effectively utilize the effects of the present invention, the resin microparticles of the embodiments of the present invention are suitable for additives in electronic materials such as semiconductor components, optical components such as light diffusers and anti-glare / low-reflection devices, additives in coatings, and additives in inks. In particular, because the resin microparticles of the embodiments of the present invention have small particle size, reduced metal content and dissolved ion content, and excellent dielectric properties, it is possible to manufacture small-sized or thin semiconductor components with a sufficient amount of resin microparticles added, thereby improving dielectric properties while preventing ion migration.

[0043] <<<<Methods for Manufacturing Resin Microparticles>>>> The resin microparticles of embodiments of the present invention can be manufactured, for example, by emulsion polymerization of the aforementioned monomers.

[0044] The method for manufacturing resin microparticles according to embodiments of the present invention typically includes a two-stage polymerization process comprising a first polymerization step and a second polymerization step. In the first polymerization step, a free radical polymerizable monomer component (M1) comprising a monofunctional monomer (b1) is emulsion polymerized. In the second polymerization step, a free radical polymerizable monomer component (M2) comprising a monofunctional monomer (b2) and a crosslinking monomer (a) is emulsion polymerized.

[0045] Emulsion polymerization refers to a polymerization method in which a liquid medium, monomer components that are poorly soluble in that medium, and surfactants are mixed, and then a polymerization initiator soluble in that medium is added to initiate polymerization. Emulsion polymerization can reduce the particle size variation of resin microparticles.

[0046] According to the manufacturing method of the present invention, resin microparticles with reduced metal and dissolved ion content and excellent dielectric properties can be manufactured.

[0047] The first polymerization step and the second polymerization step are preferably carried out in a single reactor, and more preferably continuously in a single reactor. By carrying out the first polymerization step and the second polymerization step in a single reactor, the proportion of coarse resin particles can be reduced.

[0048] <First Polymerization Process> The first polymerization step typically involves emulsion polymerization of a monomeric component (M1) containing a monofunctional monomer (b1) to produce a crude product containing a polymer. This polymer is typically used as seed particles in the second polymerization step.

[0049] (Monofunctional monomer) As a monofunctional monomer (b1), examples include the monofunctional monomers listed as other free radical polymerizable monomers (m) in the polymer P of the above-mentioned <<<<resin microparticles>>>>, and the monofunctional monomers listed as aromatic monofunctional monomers (b) in the polymer P of the above-mentioned <<<<resin microparticles>>>>. Methyl (meth)acrylate is preferred as the monofunctional monomer (b1). Depending on the circumstances, styrene is preferred as the monofunctional monomer (b1). Alternatively, the monofunctional monomer (b1) may be the same material as the monofunctional monomer (b2) in the second polymerization step described later. There may be only one monofunctional monomer (b1), or there may be two or more.

[0050] From the viewpoint of better realizing the effects of the present invention, the content of the monofunctional monomer (b1) in the monomer component (M1) is preferably 50% to 100% by mass, more preferably 80% to 100% by mass, further preferably 90% to 100% by mass, particularly preferably 95% to 100% by mass, and most preferably 98% to 100% by mass.

[0051] In the first polymerization step, as described above, by using a composition comprising a monomer component (M1), a liquid medium, a surfactant, and a polymerization initiator for emulsion polymerization, a crude product comprising seed particles of a polymer as the monomer component (M1) and a liquid medium can be obtained.

[0052] (Liquid medium) The liquid medium used in the first polymerization step is not particularly limited. The liquid medium can be, for example, water, organic solvents, and mixtures thereof. In the manufacturing method of this invention, the liquid medium is preferably an aqueous medium, and can be, for example, lower alcohols such as water, methanol, and ethanol, or mixtures of water and lower alcohols.

[0053] (surfactant) To the extent that the effects of the present invention are not impaired, any suitable surfactant may be used in the first polymerization step. There may be only one surfactant or two or more. From the viewpoint of better realizing the effects of the present invention, the surfactant preferably includes a reactive surfactant. Examples of reactive surfactants include, for example, anionic reactive surfactants and nonionic reactive surfactants. As anionic reactive surfactants, anionic reactive surfactants listed as reactive surfactant (A) in <polymer P> of <<<<resin microparticles>>>> above can be used. As nonionic reactive surfactants, nonionic reactive surfactants listed as reactive surfactant (A) in <polymer P> of <<<<resin microparticles>>>> above can be used. The surfactant preferably does not include a non-reactive surfactant.

[0054] Furthermore, in the first polymerization step, it is preferable not to use emulsifying agents other than reactive surfactants.

[0055] Relative to 100 parts by mass of monomer component (M1) in the first polymerization step, the amount of surfactant used in the first polymerization step is preferably 0.01 parts by mass to 20 parts by mass, more preferably 0.05 parts by mass to 18 parts by mass, and even more preferably 0.1 parts by mass to 16 parts by mass.

[0056] (Polymerization initiator) The polymerization initiator used in the first polymerization step can be any suitable polymerization initiator without impairing the effects of the present invention. Free radical polymerization initiators are preferred, and thermal polymerization initiators are particularly preferred. Examples of polymerization initiators include water-soluble azo compounds, persulfates (e.g., ammonium persulfate, potassium persulfate, sodium persulfate, etc.), hydrogen peroxide, organic peroxides, and oil-soluble nitrile-azo compounds.

[0057] Polymerization initiators include, for example, 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropanediamine]n hydrate (trade name "VA-057"), 4,4'-azobis(4-cyanovaleric acid) (trade name "V-501"), 2,2'-azobis[2-(2-imidazolin-2-yl)propane and its dihydrochloride (trade names "VA-061", "VA-044"), and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propamide] (trade name "VA-061", "VA-044") (trade name "VA-061"). VA-086), 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide} (trade name "VA-080"), 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide} (trade name "VA-082"), 2,2'-azobis{2-methyl-N-[2-(1-hydroxybutyl)]propionamide} (trade name "VA-085") (all from FUJIFILM Wako Pure Chemical) Water-soluble azo compounds such as those manufactured by Corporation; cumene hydroperoxide, di-tert-butyl peroxide, di-di-isopropylbenzene peroxide, benzoyl peroxide, lauroyl peroxide, dimethyl bis(tert-butylperoxy)hexane, dimethyl bis(tert-butylperoxy)hexyne-3, bis(tert-butylperoxyisopropyl)benzene, bis(tert-butylperoxy)trimethylcyclohexane, bis(tert-butylperoxy)valerate, tert-butyl peroxy-2-ethylhexanoate, benzoyl peroxide, terpene hydroperoxide, and tert-butyl peroxybenzoate, etc.; 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2-isopropylbutyronitrile), 2,2'-azobis(2,3-dimethylbutyronitrile), etc. Oil-soluble nitrile-azo compounds, including 2,2'-azobis(2,4-dimethylbutyronitrile), 2,2'-azobis(2-methylhexanonitrile), 2,2'-azobis(2,3,3-trimethylbutyronitrile), 2,2'-azobis(2,4,4-trimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(4-ethoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(4-n-butoxy-2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-formonitrile), 2-(carbamoylazo)isobutyronitrile, and 4,4'-azobis(4-cyanopentanoic acid). Alternatively, a redox initiator can be used, which is a combination of the above-mentioned polymerization initiators of persulfate and organic peroxides with reducing agents such as sodium formaldehyde sulfoxylate, sodium bisulfite, ammonium bisulfite, sodium thiosulfate, ammonium thiosulfate, hydrogen peroxide, sodium hydroxymethyl sulfinate, L-ascorbic acid or its salts, cuprous salts, and ferrous salts. Among them, those selected from 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropanediamine]n hydrate (trade name "VA-057"), 4,4'-azobis(4-cyanovaleric acid) (trade name "V-501"), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] (trade name "VA-061"), and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propamide] (trade name "VA-08") are preferred. 6”), 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide} (trade name "VA-080"), 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide} (trade name "VA-082"), 2,2'-azobis{2-methyl-N-[2-(1-hydroxybutyl)]propionamide} (trade name "VA-085") (Above, FUJIFILM One or more of the following groups are used: water-soluble azo compounds (manufactured by Wako PureChemical Corporation), 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile), 2,2'-azobis(2,4-dimethylpentanonitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carboxynitrile), 4,4'-azobis(4-cyanopentanoic acid), cumene hydroperoxide, di-tert-butyl peroxide, dicumene peroxide, benzoyl peroxide, and lauroyl peroxide, with a preference for water-soluble azo compounds. This reduces the total content of component A (resin microparticles) and the total amount of dissolved ion component B. These polymerization initiators can be used alone or in combination.

[0058] The amount of polymerization initiator used in the first polymerization step is preferably 0.01 to 5 parts by mass relative to 100 parts by mass of monomer component (M1) in the first polymerization step, more preferably 0.05 to 3 parts by mass, and even more preferably 0.1 to 1 part by mass.

[0059] The polymerization temperature of the first polymerization step can be any suitable temperature within the range that does not impair the effects of the present invention, as long as it is suitable for emulsion polymerization. Such a polymerization temperature is preferably 30°C to 120°C, and more preferably 50°C to 90°C.

[0060] The polymerization time of the first polymerization step can be any suitable time, provided it is appropriate for emulsion polymerization, without compromising the effects of the present invention. As such a polymerization time, at the initial polymerization temperature, 1 hour to 48 hours is preferred, and more preferably 1 hour to 24 hours.

[0061] <Second Polymerization Process> In the second polymerization step, emulsion polymerization is carried out using a composition containing a free radical polymerizable monomer component (M2). The composition typically includes a liquid medium, the monomer component (M2), and a surfactant, and may also include a polymerization initiator.

[0062] In the second polymerization step, typically, the monomer component (M2) is emulsion polymerized in the presence of the polymer obtained in the first polymerization step. That is, the emulsion polymerization in the second polymerization step is a seed emulsion polymerization using the polymer obtained in the first polymerization step as seed particles. Preferably, the second polymerization step is carried out by adding a composition containing the monomer component (M2) to the polymer (seed particles) obtained in the first polymerization step.

[0063] Seed emulsion polymerization is a method that uses polymers as seed particles, employs a water-soluble polymerization initiator to polymerize monomers, and allows the seed particles to grow. Specifically, seed emulsion polymerization refers to the emulsion polymerization in which a liquid medium, monomer components poorly soluble in that medium, and surfactants are mixed in the presence of seed particles formed from polymers, and a polymerization initiator soluble in that medium is added to carry out polymerization.

[0064] The seed particles can be in the form of a dispersion. The second polymerization step is preferably carried out by adding a composition containing the monomer component (M2) to the crude product obtained from the first polymerization step.

[0065] As described above, the first polymerization step and the second polymerization step are preferably carried out in a single reactor. Therefore, the second polymerization step is preferably carried out in the same reactor as the first polymerization step, and more preferably, it is carried out continuously in the reactor where the first polymerization step was carried out after the first polymerization step. Therefore, the second polymerization step is preferably carried out by introducing a composition containing the monomer component (M2) into the reactor used in the first polymerization step, which includes the crude product of the first polymerization step, to carry out seed emulsion polymerization. Here, the continuous carrying out of the first polymerization step and the second polymerization step means, for example, that after the emulsion polymerization of the first polymerization step, the polymer (seed particles) is not removed from the reactor and / or the reactor is not intentionally cooled (i.e., the crude product of the first polymerization step is not cooled) and the second polymerization step is carried out.

[0066] (Cross-linked monomers) The crosslinking monomer (a) is the same as the crosslinking monomer (a) listed in <Polymer P> of <<<<Resin Microparticles>>> above. The crosslinking monomer (a) may be used alone or in combination with two or more other monomers.

[0067] (Monofunctional monomer) The monofunctional monomer (b2) is preferably an aromatic monofunctional monomer. Examples of aromatic monofunctional monomers include those listed as aromatic monofunctional monomers (b) in the <polymer P> of the <<<<resin microparticles>>> above. The monofunctional monomer (b2) is preferably at least one selected from the group consisting of styrene, α-methylstyrene, tert-butylstyrene, and ethylvinylbenzene, more preferably at least one selected from the group consisting of styrene and ethylvinylbenzene. These aromatic monofunctional monomers (b2) can be used alone or in combination with two or more.

[0068] From the viewpoint of better realizing the effects of the present invention, the total content of the crosslinking monomer (a) and the monofunctional monomer (b2) in the monomer component (M2) is preferably 50% to 100% by mass, more preferably 80% to 100% by mass, further preferably 90% to 100% by mass, particularly preferably 95% to 100% by mass, and most preferably 98% to 100% by mass.

[0069] (Liquid medium) The liquid medium used in the second polymerization step is not particularly limited, and the medium described in the first polymerization step can be used, preferably within the same range as described in the first polymerization step. In the manufacturing method of the embodiments of the invention, the liquid medium is preferably an aqueous medium, and can be, for example, water, methanol, ethanol, or a mixture of water and a lower alcohol.

[0070] The amount of liquid medium used can be any appropriate amount without impairing the effects of the present invention. The amount of medium at the start of the second polymerization step (e.g., the total amount of medium used in the first and second polymerization steps) is preferably 10 to 5000 parts by mass, more preferably 50 to 3000 parts by mass, further preferably 100 to 2000 parts by mass, and particularly preferably 120 to 1000 parts by mass, relative to the total amount of monomer components (M1) and (M2) by mass.

[0071] (surfactant) The surfactant used in the second polymerization step may be any suitable surfactant without impairing the effects of the present invention. The surfactant described in the first polymerization step may be used in the second polymerization step. Only one surfactant may be used, or two or more surfactants may be used. From the viewpoint of better realizing the effects of the present invention, the surfactant preferably comprises a reactive surfactant.

[0072] Relative to the total amount of 100 parts by mass of monomer component (M1) and monomer component (M2), the amount of surfactant used in the second polymerization step (the amount added in the second polymerization step) is preferably 0.05 parts by mass to 7 parts by mass, more preferably 0.1 parts by mass to 5 parts by mass, and even more preferably 0.15 parts by mass to 3 parts by mass.

[0073] Relative to the total amount of 100 parts by weight of monomer component (M1) and monomer component (M2), the total amount of surfactant used in the manufacturing method of the embodiments of the present invention is preferably 0.05 parts by weight to 7 parts by weight, more preferably 0.1 parts by weight to 5 parts by weight, and even more preferably 0.15 parts by weight to 4 parts by weight.

[0074] It is preferred that a reactive surfactant is used in at least one of the first polymerization step and the second polymerization step. That is, it is preferred that at least one of the above-described compositions containing a monomer component (M1) in the first polymerization step and the above-described compositions containing a monomer component (M2) in the second polymerization step contains a reactive surfactant.

[0075] In the first and second polymerization steps, non-reactive surfactants may be used to a extent that does not impair the effects of the present invention, but it is preferable not to use non-reactive surfactants. That is, the above-described composition containing monomer component (M1) in the first polymerization step and the above-described composition containing monomer component (M2) in the second polymerization step preferably contain reactive surfactants. It should be noted that examples of non-reactive surfactants include, for example, sodium oleate; fatty acid soaps such as potassium castor oil soap; alkyl sulfate salts such as sodium lauryl sulfate and ammonium lauryl sulfate; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; alkyl naphthalene sulfonates; alkane sulfonates; dialkyl sulfosuccinates; alkyl phosphate salts; naphthalene sulfonate formaldehyde condensate; polyoxyethylene alkylphenyl ether sulfate salts; polyoxyethylene sulfonated phenyl ether phosphate; polyoxyethylene alkyl ether phosphate; polyoxyethylene alkyl sulfate salts; anionic non-reactive surfactants; and polyoxyethylene branched decyl ether, polyoxyethylene tridecyl ether, etc. Nonionic reactive surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene tridecyl ethers, polyoxyethylene isodecanyl ethers, polyoxyethylene lauryl ethers, polyether polyols, polyoxyethylene styrene phenyl ethers, polyoxyethylene naphthyl ethers, polyoxyethylene phenyl ethers, polyoxyethylene polyoxypropylene glycol, polyoxyethylene lauryl ethers, polyoxyethylene oil-based cetyl ethers, polyoxyethylene isostearate glyceryl esters, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxysorbitan fatty acid esters, polyoxyethylene alkylamines, glyceryl fatty acid esters, and oxyethylene-oxypropylene block polymers.

[0076] (Polymerization initiator) The polymerization initiator used in the second polymerization step can be any suitable free radical polymerization initiator, provided it does not impair the effects of the present invention. In the second polymerization step, the polymerization initiators listed in the first polymerization step can be used, and the preferred range is the same as that described in the first polymerization step. The polymerization initiator used in the first polymerization step can be the same as the polymerization initiator used in the second polymerization step.

[0077] Preferably, at least one of the first polymerization step and the second polymerization step uses a water-soluble azo compound as a polymerization initiator.

[0078] Relative to the total amount of 100 parts by mass of monomer component (M1) and monomer component (M2), the amount of polymerization initiator used in the second polymerization step (the amount added in the second polymerization step) is preferably 0.05 parts by mass to 5.0 parts by mass, more preferably 0.08 parts by mass to 3.0 parts by mass, and even more preferably 0.1 parts by mass to 2.0 parts by mass.

[0079] Relative to the total amount of 100 parts by mass of monomer component (M1) and monomer component (M2), the total amount of polymerization initiator used in the manufacturing method of the embodiments of the present invention is preferably 0.05 parts by mass to 5.0 parts by mass, more preferably 0.08 parts by mass to 3.0 parts by mass, and even more preferably 0.1 parts by mass to 2.0 parts by mass.

[0080] The polymerization temperature in the second polymerization step can be any suitable temperature as long as it is suitable for emulsion polymerization, without compromising the effects of the present invention. Such a polymerization temperature is preferably 30°C to 120°C, more preferably 50°C to 100°C. For example, the polymerization temperature in the second polymerization step can be set as the initial polymerization temperature of 30°C to 90°C, and then increased to a later polymerization temperature of 70°C to 120°C.

[0081] The polymerization time in the second polymerization step can be any suitable time, provided it is appropriate for emulsion polymerization, without compromising the effects of the present invention. As such a polymerization time, the initial polymerization temperature is preferably 1 hour to 48 hours, more preferably 1 hour to 24 hours.

[0082] <Other processes> After the second polymerization process described above, the particles can be washed, graded, dried, etc., as needed. Example

[0083] The present invention will be specifically described below with examples, but the present invention is not limited to these examples.

[0084] <Volume average particle size> The volume-average particle size of the resin particles was determined using a laser diffraction scattering particle size distribution measuring device (manufactured by Beckman Coulter, Inc., "LS 13 320"). By supplying a dispersion of resin particles to the device, the volume-based particle size distribution and its standard deviation of the resin particles were obtained. The arithmetic mean particle size in the obtained volume-based particle size distribution was taken as the volume-average particle size of the resin particles. The measurement conditions of the laser diffraction scattering particle size distribution measuring device are as follows: Sample dispersion module: General liquid module Medium: Ion-exchanged water Refractive index of the medium: 1.333 Refractive index of the sample: Refractive index of resin particles The refractive index of the aforementioned resin particles is the average of the weighted average obtained by dividing the refractive index of the individual polymers of each monomer used in the manufacturing process by the amount of each monomer used.

[0085] Coefficient of variation of volume average particle size The coefficient of variation (CV) of the volume average particle size of resin microparticles is calculated using the following formula: Coefficient of variation [%] = (Standard deviation of particle size distribution on a volume basis of resin particles ÷ Volume average particle size of resin particles) × 100

[0086] <Proportion of particles with a diameter of 10 μm or larger> The proportion of particles with a diameter of 10 μm or larger was determined by the Coulter Multisizer. TM The measurement was performed using a 4e (measuring apparatus manufactured by Beckman Coulter, Inc.). The measurement was performed using a Multisizer as published by Beckman Coulter, Inc. TM The 4e user manual specifies the small-hole tube for calibration. It should be noted that the orifice tube used for the measurement should be appropriately selected based on the size of the resin particles to be measured. The Current (orifice tube current) and Gain should be set appropriately according to the size of the selected orifice tube. For example, if an orifice tube with a size of 50 μm is selected, the Current (orifice tube current) should be set to -800 and the Gain should be set to 4. As the sample for testing, 0.1 g of resin particles were dispersed in 10 mL of 0.1 wt% aqueous solution of polyoxyethylene sorbitan monolaurate "Tween20" using a touch mixer (manufactured by Yamato Scientific Co., Ltd., "TOUCHMIXER MT-31") and an ultrasonic cleaner (manufactured by VELVO CLEAR Co., Ltd., "ULTRASONIC CLEANER VS-150") as the dispersion. During the test, the mixture was stirred slowly until no bubbles were generated in the beaker, and the test was completed at the point when 100,000 resin particles were measured. The proportion of particles larger than 10 μm was confirmed in the volumetric particle size distribution obtained from the test results.

[0087] <Total content of ingredient A> (Sample to be measured) The dispersion containing resin particles was dried using a spray dryer (manufactured by Sakamoto Giken Co., Ltd., equipment name: spray dryer, type: atomizer feeding method, model: TRS-3WK) under the following apparatus conditions as a test sample. (Conditions for spray dryer equipment) Dispersion feed rate containing resin particles: 25 mL / min Atomizer speed: 12000 rpm Air volume: 2 m 3 / min Inlet temperature (the inlet temperature of the inlet of the spray dryer used for spraying the dispersion containing resin particles): 150°C Outlet temperature (outlet temperature of the outlet used to discharge the dried particles in the spray dryer): 70°C (Determination Method) The total content of component A was determined as described below. Approximately 1.0 g of the above-mentioned test sample was accurately weighed and ashed at 500°C for 1 hr. The resulting ash was mixed with 1 mL of concentrated hydrochloric acid (Ultrapur-100 ultra-high purity reagent manufactured by Kanto Chemical Co., Ltd.). After filtering the insoluble portion of the mixture through ADVANTEC No.7 filter paper, the filtrate was diluted to 25 mL with distilled water to obtain the test solution. For the test solution, perform ICP emission spectroscopy analysis under the following conditions. Determine the concentration of each element using a pre-prepared calibration curve. Calculate the amount of each element using the following formula. Component concentration [ppm] = Element concentration [μg / mL] × 25 [mL] ÷ Sample volume [g] The total content (total) of component A is calculated based on the amount of each element measured. Here, elements whose measured values ​​are below the limit of quantitation (LOQ) are not considered in the calculation of the total content of component A. That is, the total content of components above the LOQ is taken as the total content of component A. The LOQ for elements P and K is 0.5 ppm, and the LOQ for other elements is 0.3 ppm. (ICP determination conditions) Measuring apparatus: Shimadzu Corporation "ICPE-9000" multi-purpose ICP emission spectrometer Elemental analysis: Al, Ba, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, P, S, Si, Sr, Zn Observation direction: Axial direction High-frequency output: 1.20 kW Carrier gas flow rate: 0.7 L / min Plasma flow rate: 10.0 L / min Auxiliary flow rate: 0.6 L / min Exposure time: 30 seconds The standard solutions used for calibration curves were: approximately 10 mg / L each of SPEX's "XSTC-13" universal mixed standard solution (31 elements mixed, matrix 5% HNO3) and "XSTC-8" universal mixed standard solution (13 elements mixed, matrix H2O / trace HF). (Ashing conditions) Measurement apparatus: Phoenix large-capacity microwave muffle furnace (manufactured by CEM Corporation) Ashing conditions: 500°C × 1 hr (sample amount = approximately 1.0 g)

[0088] <Total amount of dissolved ion component B> (Sample to be measured) The obtained resin particles were dried using a spray dryer under the same conditions as the above <Total Content of Component A>, and used as the test sample. (Determination Method) The dissolved ion component B was determined as follows: Prepare a 50 mL container and add approximately 50 mL of ion-exchanged water, rinsing three times. Accurately weigh approximately 0.2 g of the sample to be measured into the rinsed 50 mL container. Add 1 mL of ethanol (Clynsolve P) for washing, mix thoroughly, then add another 50 mL of ion-exchanged water and mix thoroughly. Perform ultrasonic washing and extraction on the resulting mixture for approximately 10 min. Then, use the liquid filtered through a 0.20 μm chromatographic plate with water as the test solution for ion chromatography determination. The standard solution was tested under the following conditions to create a calibration curve. Next, the test solution was tested under the same conditions. Using the peak area values ​​of each ion obtained from the chromatogram, the concentration of each analyte ion in the sample was determined according to the calibration curve. It should be noted that the standard solution used for the calibration curve was "Anion Mixed Standard Solution 1" manufactured by FUJIFILM Wako Pure Chemical Corporation. The amount of dissolved ions in the sample was calculated using the following formula. Dissolved ion concentration [ppm] = Measured ion concentration [μg / mL] × 51 [mL] ÷ Sample volume [g] The total amount of dissolved ion component B is calculated based on the amount of dissolved ion components of each measured ion. Here, ions with measured values ​​below the limit of quantitation (LOQ) are not considered in the calculation of the total amount of dissolved ion component B. That is, the total amount of dissolved ion components above the LQ is taken as the total amount of dissolved ion component B. The LQ is 2 ppm. (Determination conditions by ion chromatography) Measuring device: IC-2001 manufactured by Tosoh Corporation. Ion to be determined: F - Cl - NO2 - ,Br - NO3 - PO4 3- SO4 2- Chromatographic column: TOSOH "TSKGEL superIC-AZ" Mobile phase: 3.2 mM Na₂CO₃ + 1.9 mM NaHCO₃ Flow rate: 0.8 mL / min Column temperature: 40°C Injection volume: 30 μL

[0089] <Dielectric properties of resin particles> (Sample to be measured) The obtained resin particles were dried using a spray dryer under the same conditions as the above <Total Content of Component A>, and used as the test sample. (Determination Method) The dielectric properties of the samples were measured using a dielectric constant measuring apparatus (ADMS01Nc series) developed by AET Corporation. Measurements were performed at a frequency of 10 GHz, an ambient temperature of 23°C, and a relative humidity of 51 ± 1%. Based on the perturbation theory of resonators, the relative permittivity and dielectric loss tangent of the resin particles were calculated.

[0090] [Example 1] In a pressure-resistant polymerization reactor that also serves as a stirrer, thermometer, and cooling system, 240 parts by mass of deionized water and 0.03 parts by mass of Aqualon AR-1025 (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd., 25% active ingredient) as a reactive surfactant were mixed to prepare the first aqueous phase. Next, 4 parts by mass of methyl methacrylate were added to the reactor, nitrogen gas was introduced for 3 minutes, and the reactor was sealed and heated to 60°C. In a separate container, 0.04 parts by mass of 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropanediamine]n hydrate, serving as a polymerization initiator, were dissolved in 2 parts by mass of deionized water to prepare a polymerization initiator solution. The polymerization initiator solution was then added to the reactor, which had reached 60°C, and the polymerization reaction was carried out for 2 hours (first polymerization step).

[0091] In another container, 76 parts by mass of deionized water, 0.9 parts by mass of Aqualon AR-1025 as a reactive surfactant, and 0.36 parts by mass of 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropanediamine]n hydrate as a polymerization initiator were mixed to prepare a second aqueous phase. Next, 67 parts by mass of styrene and 9 parts by mass of divinylbenzene (NSStyrene Monomer Co., Ltd., DVB-810) were mixed and added to the second aqueous phase. The mixture was then stirred at 8000 rpm for 10 minutes using a TK homogenizer (manufactured by PRIMIX Corporation) to obtain a monomer mixture. The monomer mixture was added to the reactor described above after the first polymerization step for 3 hours. After the addition was completed, polymerization continued at 60°C for 2 hours, and then the temperature was raised to 85°C for another 2 hours (the second polymerization step).

[0092] After the polymerization reaction was completed, the resulting dispersion was cooled and then passed through a 500 Mesh (24 μm mesh) screen for classification to obtain a dispersion containing the resin particles of Example 1. The volume average particle size of the resin microparticles in Example 1 was 0.36 μm, and the coefficient of variation (CV) of the volume average particle size was 14%. The proportion of particles with a diameter greater than 10 μm in the resin microparticles of Example 1 was 0% by volume. The results of determining the total content of component A and the total amount of dissolved ion component B in the resin microparticles of Example 1 are shown in Table 1.

[0093] [Example 2] The amount of AqualonAR-1025 in the first polymerization step was changed from 0.03 parts by mass to 2.5 parts by mass. Otherwise, the process was carried out in the same manner as in Example 1 to obtain the resin microparticles of Example 2. The volume average particle size of the resin microparticles in Example 2 was 0.13 μm, and the coefficient of variation (CV) for the volume average particle size was 19%. The proportion of particles with a diameter greater than 10 μm in the resin microparticles of Example 2 was 0% by volume. The results of determining the total content of component A and the total amount of dissolved ion component B in the resin microparticles of Example 2 are shown in Table 1.

[0094] [Example 3] In a pressure-resistant polymerization reactor that also serves as a stirrer, thermometer, and cooling system, 240 parts by mass of deionized water and 0.01 parts by mass of Aqualon AR-1025 (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd., 25% active ingredient) as a reactive surfactant were mixed to prepare the first aqueous phase. Next, 4 parts by mass of methyl methacrylate were added to the reactor, nitrogen gas was introduced for 3 minutes, and the reactor was sealed and heated to 75°C. In another container, 0.04 parts by mass of 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] as a polymerization initiator was dissolved in 2 parts by mass of deionized water to prepare a polymerization initiator solution. The polymerization initiator solution was then added to the reactor, which had reached 75°C, and the polymerization reaction was carried out for 2 hours (first polymerization step).

[0095] In another container, 76 parts by mass of deionized water, 0.8 parts by mass of Aqualon AR-1025 as a reactive surfactant, and 0.36 parts by mass of 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] as a polymerization initiator were mixed to prepare a second aqueous phase. Next, 54 parts by mass of styrene and 22 parts by mass of divinylbenzene (NSStyrene Monomer Co., Ltd., DVB-810) were mixed and added to the second aqueous phase. The mixture was then stirred at 8000 rpm for 10 minutes using a TK homogenizer (manufactured by PRIMIX Corporation) to obtain a monomer mixture. The monomer mixture was added to the reactor described above after the first polymerization step for 5 hours. After the addition was completed, the temperature was raised to 85°C and polymerization was carried out for 3 hours, followed by a further increase to 100°C and polymerization for 5 hours (the second polymerization step).

[0096] After the polymerization reaction was completed, the resulting dispersion was cooled and then passed through a 500 Mesh (24 μm mesh) screen for classification to obtain a dispersion containing the resin particles of Example 3. The volume average particle size of the resin microparticles in Example 3 was 0.58 μm, and the coefficient of variation (CV) of the volume average particle size was 13%. The proportion of particles with a diameter greater than 10 μm in the resin microparticles of Example 3 was 0% by volume. The results of determining the total content of component A and the total amount of dissolved ion component B in the resin microparticles of Example 3 are shown in Table 1.

[0097] [Example 4] The reactive surfactant in the first polymerization step was changed from 0.03 parts by mass of Aqualon AR-1025 to 0.02 parts by mass of ELEMINOLJS-20 (manufactured by Sanyo Chemical Industries, Ltd., 40% active ingredient), and the reactive surfactant in the second polymerization step was changed from 0.9 parts by mass of Aqualon AR-1025 to 0.8 parts by mass of ELEMINOLJS-20 (manufactured by Sanyo Chemical Industries, Ltd., 40% active ingredient). Otherwise, the process was carried out in the same manner as in Example 1, and the resin microparticles of Example 4 were obtained. The volume average particle size of the resin microparticles in Example 4 was 0.34 μm, and the coefficient of variation (CV) for the volume average particle size was 13%. The proportion of particles with a diameter greater than 10 μm in the resin microparticles of Example 4 was 0% by volume. The results of determining the total content of component A and the total amount of dissolved ion component B in the resin microparticles of Example 4 are shown in Table 1.

[0098] [Example 5] The divinylbenzene (NS Styrene Monomer Co., Ltd, DVB-810) in the second polymerization step was replaced with 9 parts by mass of neopentyl glycol dimethacrylate. Otherwise, the process was carried out in the same manner as in Example 1 to obtain the resin microparticles of Example 5. The volume average particle size of the resin microparticles in Example 5 was 0.37 μm, and the coefficient of variation (CV) for the volume average particle size was 14%. The proportion of particles with a diameter greater than 10 μm in the resin microparticles of Example 5 was 0% by volume. The results of determining the total content of component A and the total amount of dissolved ion component B in the resin microparticles of Example 5 are shown in Table 1.

[0099] <Manufacturing Example 1> In a reactor that also functions as a stirrer, thermometer, and cooling system, 270 parts by mass of deionized water and 0.07 parts by mass of sodium styrene sulfonate as an emulsifying agent were mixed to prepare an aqueous phase. Next, 120 parts by mass of methyl methacrylate and 2.4 parts by mass of 1-octyl mercaptan as a chain transfer agent were mixed and added to the aqueous phase in the reactor. The reactor was purged with nitrogen for 5 minutes, then heated to 80°C. At the point of reaching 80°C, a polymerization initiator solution obtained by dissolving 0.05 parts by mass of potassium persulfate as a polymerization initiator in 10 parts by mass of deionized water was added. Nitrogen purging was then performed again for 5 minutes, and the mixture was stirred at 80°C for 5 hours to induce emulsion polymerization. Afterward, the temperature was further increased to 100°C and maintained for 3 hours before cooling to prepare a slurry containing resin particles. This slurry was used as seed particles.

[0100] [Comparative Example 1] Aqueous phase was prepared by mixing 70 parts by mass of deionized water and 0.35 parts by mass of ELEMINOLJS-20 as a reactive surfactant in a container. Oil phase was prepared by thoroughly mixing 61 parts by mass of styrene and 9 parts by mass of divinylbenzene (NS Styrene Monomer Co., Ltd., DVB-810) in another container. The oil phase was then added to the aqueous phase and stirred at 8000 rpm for 10 minutes using a TK homogenizer (PRIMIX) to obtain a monomer mixture. In a reactor that also serves as a stirrer, thermometer, and cooling system, 220 parts by mass of ion-exchanged water and 33 parts by mass of seed particles prepared in Manufacturing Example 1 were added. The reactor was purged with nitrogen for 5 minutes, and then the temperature was raised to 70°C. In another container, 0.2 parts by mass of 4,4'-azobis(4-cyanovaleric acid) was dissolved in a mixture of 5 parts by mass of ethanol and 5 parts by mass of ion-exchanged water to prepare a polymerization initiator solution. The polymerization initiator solution was added when the reactor reached 70°C. Subsequently, the monomer mixture was added to the reactor over a period of 4 hours to initiate the polymerization reaction. After the reaction, the temperature was further raised to 95°C, and the reaction was carried out for 3 hours. After polymerization, the resulting dispersion was cooled and passed through a 400-mesh sieve for classification to obtain a dispersion containing the resin particles of Comparative Example 1. The volume-average particle size of the resin microparticles in Comparative Example 1 was 0.38 μm, and the coefficient of variation of the volume-average particle size was 15%.

[0101] [Comparative Example 2] The 0.35 parts by mass of ELEMINOLJS-20 were replaced with 0.21 parts by mass of the non-reactive surfactant phosphate ester RS-610 (manufactured by Toho Chemical Co., Ltd.), and the process was otherwise the same as in Comparative Example 1, to obtain the dispersion containing resin particles in Comparative Example 2. The volume average particle size of the resin microparticles in Comparative Example 2 was 0.37 μm, and the coefficient of variation of the volume average particle size was 15%.

[0102] [Table 1]

[0103] According to the results in Table 1, the total content of component A and the total amount of dissolved ion component B in the resin microparticles obtained in Examples 1-5 are reduced, and they have excellent dielectric properties.

[0104] The resin microparticles of the embodiments of the present invention can be used in semiconductor components, etc.

Claims

1. A resin microparticle, wherein, The total content of component A, as determined by inductively coupled plasma atomic emission spectrometry, was less than 100 ppm. The total amount of dissolved ion component B, as determined by ion chromatography, was less than 100 ppm. The dielectric loss tangent at a frequency of 10 GHz is below 0.0050. Component A: Al, Ba, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, P, S, Si, Sr, and Zn Ionic components B: fluoride ions, chloride ions, nitrite ions, bromide ions, nitrate ions, phosphate ions, and sulfate ions.

2. The resin particles according to claim 1, wherein, The dielectric loss tangent is below 0.0030°.

3. The resin microparticles according to claim 1, comprising a polymer (P) obtained by reacting a composition containing a free radical polymerizable monomer component (M). The monomer component (M) comprises a cross-linking monomer (a) and an aromatic monofunctional monomer (b).

4. The resin particles according to claim 3, wherein, The crosslinking monomer (a) comprises aromatic crosslinking monomers.

5. The resin particles according to claim 3, wherein, The composition contains a reactive surfactant (A).

6. The resin microparticles according to claim 1, wherein the volume average particle size is 0.05 μm or more and 2 μm or less.

7. The resin particles according to claim 1, wherein, The proportion of particles with a diameter of 10 μm or larger is less than 0.01% by volume.

8. The resin particles according to claim 1 are dry powders.

9. The resin microparticles according to claim 1, wherein the coefficient of variation of the volume average particle size is less than 25%.

10. The resin microparticles according to any one of claims 1 to 9, used as an additive for electronic materials.

11. The resin microparticles according to any one of claims 1 to 9, which are used as additives for optical materials.

12. The resin microparticles according to any one of claims 1 to 9, used as an additive for coatings.

13. The resin particles according to any one of claims 1 to 9, used as an additive for inks.

14. A method for manufacturing resin microparticles according to any one of claims 1 to 9, It involves a two-stage polymerization process, including a first polymerization step and a second polymerization step. In the first polymerization step, an emulsion polymerization is performed on a free radical polymerizable monomer component (M1) containing a monofunctional monomer (b1). In the second polymerization step, a free radical polymerizable monomer component (M2) comprising a monofunctional monomer (b2) and a crosslinking monomer (a) is emulsion polymerized.

15. The method for manufacturing resin microparticles according to claim 14, wherein, The first polymerization step and the second polymerization step are carried out in a single reactor.

16. The method for manufacturing resin microparticles according to claim 14, wherein, A reactive surfactant is used in at least one step selected from the first polymerization step and the second polymerization step.

17. The method for manufacturing resin microparticles according to claim 14, wherein, A water-soluble azo compound is used as a polymerization initiator in at least one step selected from the first polymerization step and the second polymerization step.

18. The method for manufacturing resin microparticles according to claim 14, wherein, No non-reactive surfactants are used in the first polymerization step and the second polymerization step.

19. The method for manufacturing resin microparticles according to claim 14, wherein, The monofunctional monomer (b2) in the second polymerization step comprises an aromatic monofunctional monomer, and the crosslinking monomer (a) comprises an aromatic crosslinking monomer.

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