JP5195342B2 - Core-shell structured particles, composition, dielectric composition and capacitor - Google Patents

Description

  The present invention relates to core-shell structured particles. More specifically, the present invention relates to core-shell structured particles suitably used for a dielectric composition, a paste composition in which the core-shell structured particles are dispersed in a solvent or a resin solution, a dielectric composition obtained using the same, and a capacitor. .

As a method for producing a dielectric composition for a capacitor incorporated in a mounting substrate, a method of applying, drying and curing a paste composition in which high dielectric constant inorganic particles are dispersed in a resin is known (for example, patents). References 1-2). However, in a composition in which high dielectric constant inorganic particles are simply dispersed in a resin, voids are generated due to aggregation of the high dielectric constant inorganic particles, and it is difficult to obtain sufficient film strength as a dielectric composition. There was a problem that the adhesive strength of the was insufficient.
Japanese Patent Laying-Open No. 2005-38821 (Claims) JP 2004-285105 A (Claims)

  An object of the present invention is to provide core-shell structured particles constituting a dielectric composition having a high adhesive strength with an electrode material and having a high film strength, a composition using the same, a dielectric composition, and a capacitor. And

That is, the present invention is a core-shell structure particle having a core containing high-permittivity inorganic particles having a perovskite crystal structure and a shell containing (a) a resin having a polymerizable group, and having an average shell thickness The resin having a polymerizable group of 1 nm or more and 50 nm or less is formed by polymerizing a compound having at least two kinds of polymerizable groups, and has at least two kinds of polymerizable groups. compound is (1) a compound having an addition-polymerizable group and condensation polymerizable group, addition polymerizable group is a carbon - carbon double bond, e epoxy group, oxetane group selected, condensation polymerizable group is a carboxyl group, an isocyanate group, those selected from a hydroxyl group, or (2) a carbon - carbon double bonds, epoxy groups and / or Okise A shell structured particle - a compound having an emission group, the core is either.

  By using the core-shell structured particles of the present invention, it is possible to obtain a dielectric composition having a large relative dielectric constant and a large adhesive force and film strength with the electrode material.

  The core-shell structured particles of the present invention have a core and a shell covering at least a part of the core. The core is composed of high dielectric constant inorganic particles having a perovskite crystal structure, and the shell is (a) polymerizable. Organic-inorganic composite particles made of a group-containing resin (hereinafter referred to as “shell resin”). By coating the surface of the high dielectric constant inorganic particles with a resin layer in advance, aggregation of the high dielectric constant inorganic particles can be prevented when preparing a composition in which the high dielectric constant inorganic particles are dispersed. As a result, when the composition is cured, the generation of voids due to poor dispersibility of the particles can be suppressed, and in particular, a high strength film can be obtained even when the high dielectric constant inorganic particles are highly filled. In addition, since the core does not come into contact with the electrode material, it is possible to obtain a dielectric composition excellent in adhesive strength with the electrode material.

  Further, since the polymerizable group of the shell resin can be polymerized at the time of curing, a film having higher strength can be obtained. Furthermore, the reactivity of the polymeric group which shell resin has can be optimized because the average thickness of a shell is 1 nm or more and 50 nm or less.

  In the core-shell structured particles of the present invention, the shell resin is formed by polymerizing a compound having at least two kinds of polymerizable groups on the core surface. Examples of the polymerizable group include addition polymerizable groups such as a carbon-carbon double bond, an acrylic group, a vinyl group, an epoxy group, and an oxetane group, and a condensation polymerizable group such as a carboxyl group, an isocyanate group, and a hydroxyl group. .

  The compound having at least two kinds of polymerizable groups remains without consuming other kinds of polymerizable groups even if a certain polymerizable group is consumed at the time of shell formation. When the remaining polymerizable group is polymerized and cured in the paste composition, the strength of the resulting film is improved.

  Thus, in order to react only a part of the polymerizable groups at the time of shell formation, the compound having at least two kinds of polymerizable groups has two or more kinds of polymerizable groups having different reactivity among the above. It is preferable. For example, having an addition polymerizable polymerizable group and a condensation polymerizable polymerizable group, having a radical polymerizable polymerizable group and a cationic or anionic polymerizable group, photopolymerization For example, having a polymerizable polymerizable group and a thermally polymerizable group. It is also preferable to have a plurality of thermopolymerizable polymerizable groups having different polymerization initiation temperatures. Among these, it is particularly preferable to have one or more polymerizable groups selected from the group consisting of a carbon-carbon double bond, an acrylic group and a vinyl group, and an epoxy group and / or an oxetane group.

  Specific examples of such compounds include glycidyl methacrylate, 2-isocyanatoethyl acrylate, 1,1- (bisacryloyloxymethyl) ethyl isocyanate, 2- (2-isocyanatoethyloxy) ethyl methacrylate, methacrylic acid, and the like. Is mentioned. Among these, glycidyl methacrylate having the same reactive group as an epoxy resin widely used as a mounting substrate resin is preferably used. Since the unsaturated bond of glycidyl methacrylate is easily polymerized by a radical reaction utilizing light or heat, it can be shelled by polymerizing with the monomers unevenly distributed on the surface of the core particles. Since the epoxy group remains as a polymerizable group even after being shelled, after mixing with a curing agent, the shell resin can be reacted by heat treatment or the like to form a single polymer network.

  The core of the core-shell structured particle of the present invention preferably covers the core completely. However, as long as the core-shell structured particle is dispersed in the matrix resin and the polymer network is completed, sufficient strength can be obtained. If present, the core does not necessarily have to be completely coated.

  The average thickness of the shell of the core-shell structured particles of the present invention is 1 nm or more and 50 nm or less. If the average thickness of the shell resin is 50 nm or less, the reaction rate with the curing agent is improved, the amount of unreacted polymerizable groups of the shell resin in the dielectric composition is reduced, and the film strength of the dielectric composition Can be increased. Moreover, high filling of high dielectric constant inorganic particles is possible, and a dielectric composition having a high relative dielectric constant can be obtained. More preferably, it is 30 nm or less. If the average thickness of the shell is 1 nm or more, the swelling of the shell resin during the preparation of the composition containing the core-shell structure particles can be suppressed, and the core-shell structure can be maintained in the composition. The film strength of the object can be increased. More preferably, it is 10 nm or more. When the average thickness of the shell is greater than 50 nm, the reaction rate between the shell resin and the curing agent decreases, and the amount of unreacted polymerizable groups of the shell resin in the dielectric composition increases. As a result, the film strength of the dielectric composition decreases, which is not preferable.

  In the present invention, the average thickness of the shell refers to a value obtained as follows. That is, TEM (transmission electron microscope) observation of the produced core-shell structured particles was performed, and the thickness of 10 shells was measured for the core-shell structured particles desired to be measured from the obtained TEM photograph. The average value of the eight values excluding the value and the minimum value is defined as the average thickness of the shell layer. In addition, when the shell part of several core-shell structure particle | grains is contacting, the area | region which is contacting shall not be included in a measurement point.

  The core-shell structured particles of the present invention contain high dielectric constant inorganic particles whose core has a perovskite crystal structure. The high dielectric constant inorganic particles having a perovskite crystal structure are inorganic particles having a perovskite crystal structure or a composite perovskite crystal structure and having a relative dielectric constant of 50 or more. Examples of such inorganic particles include barium titanate, barium zirconate titanate, strontium titanate, calcium titanate, bismuth titanate, magnesium titanate, barium neodymium titanate, and barium tin titanate. , Barium magnesium niobate, barium magnesium tantalate, lead titanate, lead zirconate, lead zirconate titanate, lead niobate, lead magnesium niobate, lead nickel niobate, tungstic acid Examples thereof include inorganic particles such as lead-based, calcium tungstate, magnesium tungstate, and titanium dioxide. The barium titanate system includes solid solutions based on barium titanate in which some elements in the barium titanate crystal are replaced with other elements or other elements are infiltrated into the crystal structure. It is a generic name. Other barium zirconate titanate, strontium titanate, calcium titanate, bismuth titanate, magnesium titanate, barium neodymium titanate, barium tin titanate, barium magnesium niobate, magnesium tantalate Barium, lead titanate, lead zirconate, lead zirconate titanate, lead niobate, lead magnesium niobate, lead nickel niobate, lead tungstate, calcium tungstate, magnesium tungstic acid The same is true for lead-based materials, and is a generic term that includes solid solutions that use each as a base material.

  In addition, high dielectric constant inorganic particles having a perovskite crystal structure or a composite perovskite crystal structure can be used alone or in combination of two or more. When obtaining a dielectric composition having a higher dielectric constant, it is preferable to use a compound mainly composed of barium titanate from the viewpoint of compatibility with commercial convenience. However, a shifter, a depressor agent, etc. may be contained in a small amount for the purpose of improving dielectric properties and temperature stability.

  The high dielectric constant inorganic particles having a perovskite crystal structure preferably have a relative dielectric constant of 50 to 30,000. When high dielectric constant inorganic particles having a relative dielectric constant of 50 or more are used, the relative dielectric constant of the obtained dielectric composition can be sufficiently increased. Further, when the relative dielectric constant of the high dielectric constant inorganic particles is 30000 or less, the temperature dependence of the relative dielectric constant of the obtained dielectric composition can be easily reduced. The relative dielectric constant of the high dielectric constant inorganic particles having a perovskite crystal structure is the relative dielectric constant of a sintered body obtained by heating and firing the high dielectric constant inorganic particles having a perovskite crystal structure as a raw material powder. Point to the rate. The relative dielectric constant of the high dielectric constant inorganic particles having a perovskite crystal structure is measured, for example, by the following procedure. A paste composition is prepared by mixing high dielectric constant inorganic particles with a binder resin such as polyvinyl alcohol, an organic solvent or water, and then filled into a pellet molding machine and dried to obtain a pellet-like solid. . By sintering the pellet-like solid at, for example, about 900 to 1200 ° C., the binder resin is decomposed and removed, the high dielectric constant inorganic particles having a perovskite crystal structure are sintered, and the sintering is made of only inorganic components. You can get a body. At this time, the voids in the sintered body are sufficiently small, and the porosity calculated from the theoretical density and the measured density is required to be 1% or less. Upper and lower electrodes are formed on this sintered pellet, and the relative dielectric constant is calculated from the measurement results of capacitance and dimensions.

  Examples of methods for producing high dielectric constant inorganic particles having a perovskite crystal structure include solid phase reaction methods, hydrothermal synthesis methods, supercritical hydrothermal synthesis methods, sol-gel methods, oxalate methods, and alkoxide methods. . Use hydrothermal synthesis method, supercritical hydrothermal synthesis method, or sol-gel method because it is easy to produce high-permittivity inorganic particles with perovskite crystal structure with small particle size and uniform size Is preferred.

  The particle diameter of the high dielectric constant inorganic particles having a perovskite crystal structure is not particularly limited, but is preferably 0.05 μm or more or 1 μm or less. When the particle diameter of the high dielectric constant inorganic particles is 0.05 μm or more, it is easy to increase the relative dielectric constant of the high dielectric constant inorganic particles. When the particle diameter of the high dielectric constant inorganic particles is 1 μm or less, the specific surface area of the core-shell structure particles increases, resulting in the formation of many networks between the shell and matrix resin, improving the film strength, The film thickness of the dielectric composition can be reduced so that the capacitance can be sufficiently increased.

  Examples of the shape of the high dielectric constant inorganic particles having a perovskite crystal structure include a spherical shape, a substantially spherical shape, an elliptical spherical shape, a needle shape, a plate shape, a scale shape, a rod shape, and a cubic shape (dice). It is preferably spherical. This is because the high dielectric constant inorganic particles having a spherical or substantially spherical perovskite crystal structure have a small specific surface area, and therefore do not easily cause aggregation of the high dielectric constant inorganic particles or a decrease in resin fluidity during filling. Of these, one can be used alone, or two or more can be used. The high dielectric constant inorganic particles are preferably hydrophobized with a silane coupling agent or the like in order to enhance the adsorption of surfactant molecules in an aqueous solvent.

  As silane coupling agents, methyltrimethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, hexamethyldisilazane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane Etc.

  Although the manufacturing method of core-shell structure particle | grains is not specifically limited, It can manufacture with the following methods. High dielectric constant inorganic particles having a perovskite crystal structure are dispersed in an aqueous solvent containing a surfactant. Surfactants include anionic surfactants such as fatty acid sodium, alkyl polyoxyethylene sulfate and alkylbenzene sulfonate, cationic surfactants such as alkyltrimethylammonium salt and dialkyldimethylammonium salt, polyoxyethylene Nonionic surfactants such as alkyl ethers and alkyl monoglyceryl ethers may be mentioned, among which sodium lauryl sulfate is preferable, and two or more of these may be contained. Examples of the aqueous solvent include water, methanol, ethanol and the like, and water is preferable from the viewpoint of the adsorption force of the surfactant molecules on the surface of the core particles. Moreover, you may contain 2 or more types of these. The dispersing method can be efficiently performed by using an ultrasonic wave, a homogenizer, a ball mill, other media dispersers, and the like. In addition, when methanol or ethanol is used, particles may be settled, but even in such a case, it is possible to proceed to the following process as it is.

  Next, the dispersion liquid obtained by this and the compound which has at least 2 or more types of polymeric group are mixed. The compound having a polymerizable group may be dissolved in a solvent. Examples of the solvent used at this time include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether acetate and the like.

  Thereafter, a compound having a polymerizable group is polymerized to form a shell layer on the surface of the high dielectric constant inorganic particles. The polymerization method varies depending on the type of polymerizable group to be polymerized. For example, when an epoxy group or an isocyanate group is polymerized, it is preferably thermally polymerized. On the other hand, when an unsaturated bond-containing group is polymerized, it is preferable to perform thermal polymerization or photopolymerization.

  When polymerizing an epoxy group or an isocyanate group, it is preferable to mix a curing agent or a curing accelerator in advance. These may be added in a state of being mixed with a solution of a compound having a polymerizable group, or may be prepared separately from a solution of a compound having a polymerizable group. If the polymerizable group is an epoxy group, a curing agent generally used for an epoxy resin can be exemplified, and examples thereof include an amine curing agent, an acid anhydride curing agent, and a phenol curing agent. Moreover, you may contain 2 or more types of these hardening | curing agents. In addition, if the polymerizable group is an isocyanate group, alcohol-based or amine-based substances are generally used. Furthermore, you may contain a hardening accelerator with a hardening | curing agent or without a hardening | curing agent. Examples of the curing accelerator include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, triphenylphosphine, tris (2, And metal chelate compounds such as 4-pentadionato) cobalt.

  When polymerizing the unsaturated bond-containing group, a polymerization initiator may be added. The polymerization initiator may be added in a state of being mixed with a solution of a compound having a polymerizable group, or may be prepared separately from a solution of a compound having a polymerizable group. As the polymerization initiator, a thermal polymerization initiator that generates radicals by heating or a photopolymerization initiator that generates radicals by light is preferably used. Examples of the thermal polymerization initiator include azo compounds such as azobisisobutyronitrile and organic peroxides such as benzoyl peroxide. Examples of the photopolymerization initiator include oxime, imidazole, coumarin, benzophenone, and thioxanthone.

  When thermal polymerization of epoxy groups or isocyanate groups is performed during resin formation, some of the unsaturated bond-containing groups react with the heat of reaction, and it may be necessary to add a radical polymerization inhibitor or the like to prevent this. . Therefore, among these, it is preferable to polymerize an unsaturated bond-containing group at the time of resin formation and leave a polymerizable group such as an epoxy group or an isocyanate group.

  Lowering the polymerization temperature is preferable because melting of the shell resin of the core-shell structure particles can be suppressed and aggregation of the core-shell structure particles can be prevented. On the other hand, if the polymerization temperature is too low, the polymerization may not proceed sufficiently. Therefore, the polymerization temperature is preferably adjusted to a range in which the polymerization can proceed sufficiently and the aggregation of the core-shell structure particles can be prevented. In the case where a polymerization initiator is used, it is preferable that the temperature be in the vicinity of the polymerization initiator start temperature.

  When the core-shell structure particle dispersion formed by forming a shell is mixed with an amphoteric solvent such as ethanol, the core-shell structure particles are precipitated. The core-shell structured particles can be separated and obtained by filtering the precipitate. When the core-shell structured particles are produced in methanol or ethanol, they may be precipitated from the beginning as described above. In this case, the reaction solution may be filtered as it is.

  The thickness of the shell can be adjusted by the mixing ratio of the high dielectric constant inorganic particles having a perovskite crystal structure and the compound having at least two kinds of polymerizable groups. Generally, the thickness of the shell tends to increase as the content ratio of the compound having at least two kinds of polymerizable groups increases. Moreover, the thickness of the shell of each core-shell structure particle | grain can be made uniform by setting it as reaction reaction temperature vicinity of the initiator which uses reaction temperature, or a hardening | curing agent.

  Next, the composition having the core-shell structured particles of the present invention and (b) a compound capable of reacting with the polymerizable group of the shell layer will be described. In the composition of the present invention, (b) the compound capable of reacting with the polymerizable group of the shell layer can be polymerized by reacting with the polymerizable group contained in the shell resin in the core-shell structured particles. It is suitably used as a material for forming a high film.

  Here, (b) the compound capable of reacting with the polymerizable group of the shell layer is a thermal polymerization initiator or photopolymerization initiator when the polymerizable group contained in the shell resin is an unsaturated bond-containing group. When the polymerizable group contained in the shell resin is an epoxy group, an isocyanate group or the like, it indicates a curing agent. Examples of the thermal polymerization initiator, photopolymerization initiator, and curing agent include the same ones as described above.

  Among these, since the core-shell structured particles of the present invention preferably have a polymerizable group such as an epoxy group or an isocyanate group, the composition of the present invention has a curing agent capable of reacting with these groups. It is preferable.

  The composition of the present invention does not have to have only core-shell structured particles having an average shell thickness of 1 nm to 50 nm. For example, even when the shell thickness is adjusted to be substantially uniform by the above-described method for producing core-shell structured particles of the present invention, the core-shell structured particles having an average shell thickness of less than 1 nm or more than 50 nm are partially Can happen. However, in such a case, since the production amount is usually very small, there is no problem even if the obtained core-shell structured particles are used as they are for the production of the composition. More generally, 90% by weight or more of the core-shell structure particles having an average shell thickness of 1 nm to 50 nm in the total amount of the core-shell structure particles are contained, or the core-shell structure in the composition TEM observation of the particles, 100 core-shell structure particles were randomly selected from the obtained TEM photograph, and the thickness of 10 shells was measured for each particle, and the maximum value and the minimum value were determined for each particle. When all eight values excluding the values are collected, the average of all 800 measurement results falls within the range of 1 to 50 nm.

  The composition of the present invention may further contain a stabilizer, a dispersant, an anti-settling agent, a plasticizer, an antioxidant and the like, if necessary.

  The composition of the present invention may further have (c) a matrix resin. By adding the matrix resin, the fluidity of the prepared paste composition is improved, and characteristics such as heat resistance, chemical resistance, and photosensitivity can be imparted to the dielectric composition. (C) The matrix resin is not particularly limited, but a thermosetting resin is preferable. For example, an epoxy resin, a phenol resin, a siloxane resin, a polyimide resin, a polyimide precursor resin such as polyamic acid, an acrylic resin, a cyanate resin, a benzocyclobutene resin, and the like can be given. From the viewpoint of dispersibility of the core-shell structure particles, an epoxy resin is preferably used. Here, the epoxy resin is a resin having a prepolymer containing two or more epoxy groups (oxirane rings) in the molecular structure. Further, it is preferable that the matrix resin has a polymerizable group because a polymer network is formed between the shell and the matrix resin by the action of the curing agent, and the film strength is increased. Examples of the resin having a polymerizable group include an epoxy resin and a cyanate resin.

  The content of the high dielectric constant inorganic particles in the dielectric composition produced using the composition of the present invention is preferably 50% by weight or more and 90% by weight or less. When the content of the high dielectric constant inorganic particles in the dielectric composition is 50% by weight or more, it is preferable that the relative dielectric constant tends to be sufficiently large for use as a dielectric composition for a capacitor. It is preferable that the content of the high dielectric constant inorganic particles in the dielectric composition is 90% by weight or less because the film strength of the dielectric composition tends to increase.

  The content of the (c) matrix resin in the dielectric composition is preferably 40% by weight or less. When the content of the (c) matrix resin in the dielectric composition is 40% by weight or less, the relative dielectric constant tends to be sufficiently large for use as a dielectric composition for a capacitor.

  The composition of the present invention may be in the form of a paste or a so-called sheet. When used as a paste composition, the paste composition can be obtained by mixing and dispersing the core-shell structured particles and (b) the compound that reacts with the polymerizable group of the shell layer with a solvent or matrix resin solution. . The method for dispersing the core-shell structured particles in the solvent or (c) the matrix resin or the matrix resin solution is not particularly limited. For example, a method such as ultrasonic dispersion, ball mill, roll mill, clear mix, homogenizer, or media disperser is used. However, it is particularly preferable to use a ball mill or a homogenizer in terms of dispersibility.

  As a solvent used for the shell resin or the matrix resin solution, a solvent capable of dissolving the resin may be appropriately selected. For example, alcohols such as ethanol, i-propanol, n-butanol, benzyl alcohol, isobutyl alcohol, methoxymethylbutanol, aromatic hydrocarbons such as chlorobenzene, benzene, toluene, xylene, mesitylene, methyl cellosolve, ethyl cellosolve, butyl cellosolve Cellosolves such as methyl cellosolve acetate, ethyl cellosolve acetate, cellosolve esters such as butyl cellosolve acetate, propylene glycol esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 1,2-dimethoxyethane, 1,2 -Ethers such as diethoxyethane, tetrahydrofuran, anisole, methyl ethyl ketone, methyl isobuty Ketones such as ketone, methyl-n-amyl ketone, cyclohexanone, γ-butyrolactone, γ-butyrolactam, dioxane, acetone, cyclohexanone, cyclopentanone, N, N-dimethylformamide, dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, Examples include sulfolane, tetrahydrofuran, isophorone, trichloroethylene, ethyl lactate, butyl acetate, propylene glycol monomethyl ether, and the like.

  Moreover, the composition can be formed into a sheet by applying the paste composition thus obtained onto a substrate and drying it. This sheet is an uncured sheet in which the solvent is volatilized, and is a so-called B stage sheet. The base material may be anything as long as it can support the sheet, such as metal, glass, ceramics, and resin, and a known material can be used. Moreover, when using as a B stage sheet | seat, you may have a release film for surface protection. As the release film, a known film such as a polyethylene film such as PET is used.

  Next, the capacitor of the present invention will be described. The capacitor of the present invention comprises a dielectric composition obtained by curing the composition of the present invention between electrodes.

  The upper electrode and the lower electrode are preferably metal foils, and examples thereof include copper, aluminum, gold, silver, stainless steel, nickel, and chromium. Among these, copper or an alloy containing copper can be preferably used. In addition, the upper electrode and / or the lower electrode is a conductive material in which a metal layer or conductive particles containing copper, aluminum, gold, silver, stainless steel, nickel, chromium, etc. formed by plating, vapor deposition or sputtering are dispersed in a resin. A paste can also be used.

  As a method for obtaining the capacitor of the present invention, for example, there are the following methods. First, a paste composition is prepared, the paste composition is applied on an electrode formed on a substrate, and the solvent is removed by heating or the like. Then, the board | substrate with which metal foil and the electrode were formed is laminated, the heat processing for resin polymerization is performed, and a capacitor is formed.

  Examples of the substrate include, but are not limited to, silicon wafers, ceramics, gallium arsenide, organic circuit substrates, inorganic circuit substrates, and circuit constituent materials disposed on these substrates. Examples of organic circuit boards include glass-based copper-clad laminates such as glass cloth / epoxy copper-clad laminates, composite copper-clad laminates such as glass nonwoven fabrics / epoxy copper-clad laminates, polyetherimide resin substrates, Examples include heat-resistant / thermoplastic substrates such as ether ketone resin substrates and polysulfone resin substrates, polyester copper-clad film substrates, and polyimide copper-clad film substrates. Examples of the inorganic circuit board include ceramic substrates such as an alumina substrate, an aluminum nitride substrate, and a silicon carbide substrate, and metal substrates such as an aluminum base substrate and an iron base substrate.

  Alternatively, a capacitor can be obtained by bonding a B-stage sheet with a metal foil to a substrate on which an electrode is formed and curing it by heat treatment. A B stage sheet with a metal foil is obtained by laminating a metal foil on a B stage sheet previously formed on another base material and peeling the base material. Alternatively, the B-stage sheet may be formed by applying and drying the paste composition directly on the metal foil.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. In addition, evaluation of the core-shell structure particles and the dielectric composition in the examples was performed by the following method. The materials and evaluation methods used in each example and comparative example are as follows.

<Inorganic particles>
“BTO-150-S02” Product name: Barium titanate, manufactured by Toda Kogyo Co., Ltd., average particle size 0.15 μm
“BT-01” Product name: Barium titanate, manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size 0.1 μm
"BT-02" Product name: Barium titanate, manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size 200 nm
“BT-05” Product name: Barium titanate, manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size 0.5 μm
“BT-07” Product name: Barium titanate, manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size 0.7 μm.

<Shell resin raw material>
“Light Ester G” Product name: Glycidyl methacrylate, Kyoeisha Chemical Co., Ltd. “Karenzu AOI” Product name: 2-isocyanatoethyl acrylate, Showa Denko Co., Ltd. “Light Ester A” Product name: Methacrylic acid, Kyoeisha Chemical Co., Ltd. “Light Ester E” manufactured by Kyoeisha Chemical Co., Ltd. “Light Ester IB” manufactured by Kyoeisha Chemical Co., Ltd. <Hardener>
"2PZ" Product name: Imidazole-based epoxy resin curing agent, manufactured by Shikoku Kasei Kogyo Co., Ltd. "1B2PZ" Product name: Imidazole-based epoxy resin curing agent, manufactured by Shikoku Kasei Kogyo Co., Ltd. "2E4MZ" Product name: Imidazole-based epoxy resin curing agent "Ricacid MH" manufactured by Shikoku Kasei Kogyo Co., Ltd. Product name: Acid anhydride epoxy resin curing agent, "3075W" manufactured by Shin Nippon Chemical Co., Ltd. Product name: Amine epoxy resin curing agent, "3160S" manufactured by Japan Epoxy Resin Co., Ltd. "Product name: amine epoxy resin curing agent, manufactured by Japan Epoxy Resin Co., Ltd.

<Matrix resin>
"Epicoat 828" Product name: Epoxy resin, manufactured by Japan Epoxy Resin Co., Ltd.

  "PW-1000" Product name: Polyimide coating agent, manufactured by Toray Industries, Inc., solid content 40 wt%.

  "PW-1200" Brand name: Polyimide coating agent, manufactured by Toray Industries, Inc., solid content 40 wt%.

  “PW-2100” Product name: polyimide coating agent, manufactured by Toray Industries, Inc., solid content 40 wt%.

  “PW-3000” trade name: polyimide coating agent, manufactured by Toray Industries, Inc., solid content 40 wt%.

"Epicoat 4004P" Product name: Epoxy resin, Japan Epoxy Resin Co., Ltd. "Epicoat 1256" Product name: Epoxy resin, Japan Epoxy Resin Co., Ltd. "Epicoat 152" Product name: Epoxy resin, Japan Epoxy Resin Co., Ltd. "Epicron" Product name: Epoxy resin, manufactured by DIC Corporation “Epicron 7050” Product name: Epoxy resin, manufactured by DIC Corporation “Epicron 2050” Product name: Epoxy resin, manufactured by DIC Corporation

<Measurement of average thickness of shell>
The prepared core-shell structured particles are observed with a TEM using H-7100FA (manufactured by Hitachi, Ltd.), and the thickness of 10 shells is measured for the core-shell structured particles desired to be measured from the obtained TEM photograph. The average value of eight values excluding the maximum and minimum values was taken as the average thickness of the shell. In addition, when the particles are in contact with each other via the shell resin, the contacted portion was not included in the measurement location.

<Dielectric properties>
The measurement electrode was a circular pattern having a diameter of 10 mm. The relative dielectric constant of the dielectric composition was measured in accordance with JIS K 6911 (2006) using the impedance analyzer 4294A and sample holder 16451B (both manufactured by Agilent Technologies) for the capacitance at 1 MHz in the measurement target region.

<Peel strength>
The surface of the B-stage dielectric sheet with copper foil is bonded to the copper foil-bonded FR-4 substrate and pressed while heating at 175 ° C. for 1 hour, and then a resist pattern is formed on the copper foil. After etching the copper foil with the ferric solution, the resist was removed to form a 2 mm wide copper pattern. The edge of this 2 mm wide copper foil layer is peeled off a little, the end is sandwiched between “Tensilon” UTM-4-100 (manufactured by TOYO-BOLDWIN), and the dielectric sheet is subjected to a pulling speed of 50 mm / min and a 90 ° peeling condition. The copper foil layer was peeled off, and the maximum peel force (N / cm) was defined as the peel strength.

<Reaction rate>
As a reference measurement, 100 parts by weight of a monomer used as a raw material for the shell resin and 2 parts by weight of a polymerization initiator were added to 50 parts by weight of butyl acetate, and the mixture was heated and stirred to react an acrylic group to prepare a polymer solution. A predetermined amount of a curing agent was added and mixed into an aluminum cell for DSC measurement, heated at 70 ° C. to volatilize the solvent, and then used with a DSC measuring instrument (DSC 6220, manufactured by SII Technology Co., Ltd.). Then, measurement was performed under the following conditions to obtain a peak area value. Next, DSC measurement was performed on the dielectric composition obtained by heating the paste composition prepared in each example and comparative example at 175 ° C. for 1 hour under the same conditions, and the obtained peak area value was used. The reaction rate was calculated by the following formula. In addition, the monomer, the polymerization initiator, and the curing agent used for the reference were those corresponding to each example and comparative example.
Reaction rate = ((peak area value of reference−peak area value of dielectric composition) / peak area value of reference) × 100 (%)
Measurement conditions are under nitrogen, a heating rate of 5 ° C / min, and a maximum temperature of 200 ° C.

<Membrane strength>
If there was no crack in the B-stage dielectric sheet obtained in each of the examples and comparative examples, the film strength determination was evaluated as ◯, and if there was a crack, the film strength determination was determined as x.

<5% weight loss temperature>
The paste obtained in each example and comparative example was spin-coated on a silicon wafer, heated in a nitrogen atmosphere, and cured. The curing temperature was 200 ° C for 1 hour in Examples 1 to 29, and 1 hour at 320 ° C in Examples 30 to 45. The obtained cured film was shaved off and placed in an aluminum cell for TG-DTA, and measured under the conditions of TG-DTA measuring instrument (TG / DTA6200, manufactured by SII Technology Co., Ltd.) to obtain a 5% weight loss temperature.
The measurement conditions are the atmospheric temperature, the heating rate 5 ° C / min, and the maximum temperature 600 ° C.

<Film thickness>
The film thickness of the coating film was calculated | required by measuring the level | step difference of a coating film and a board | substrate by the stylus method using Surfcom 1400 (made by Tokyo Seimitsu Co., Ltd.).

Example 1
To a three-necked flask, 0.89 g of sodium lauryl sulfate (2 wt% with respect to the filler) and 500 g of pure water were added, and dissolved by stirring. Thereto, 44.4 g of barium titanate BTO-150-S02 was added and dispersed by stirring at 80 ° C. for 2 hours. A solution in which 0.11 g of azobisisobutyronitrile (AIBN) (2 wt% with respect to the monomer) was dissolved in 5.6 g of glycidyl methacrylate was dropped, and then stirred at 80 ° C. for 6 hours to polymerize glycidyl methacrylate. The core-shell structure particle dispersion in water was obtained. Next, the core-shell structured particle dispersion in water was dropped into ethanol to aggregate the core-shell structured particles. This liquid is filtered through a 1 μm filter, and the filtrate is dried to obtain a core having an average shell thickness of 15 nm and a core content (indicating the weight ratio of the core in the core-shell structure particles) of 88.3 wt%. 45 g of shell structure particle powder was obtained. Next, 45 g of core-shell structured particle powder and 0.26 g of a curing agent 2PZ (manufactured by Shikoku Kasei Kogyo Co., Ltd.) were added to 9.0 g of butyl acetate and mixed to prepare a paste composition.

  Using a micro bar coater (manufactured by Inoue Kinzoku Kogyo Co., Ltd.), the paste composition was coated on a roll-shaped 18 μm thick copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd., TQ-VLP). After coating to 10 μm, the solvent was removed, and the film surface was laminated with a cover film to prepare a B-stage dielectric sheet with a roll of copper foil. The cover film was a 12 μm thick polypropylene film. The conveyance speed of the copper foil was 1.4 m / min, and the drying temperature was 120 ° C. When wound up into a roll, no unevenness or cracking occurred.

  After blackening the surface copper foil of the copper foil pasted FR-4 substrate, the surface on the dielectric sheet side of the B stage dielectric sheet with the copper foil was bonded and pressed while heating at 175 ° C. for 1 hour, An evaluation sample was produced.

  When the peel strength of the copper foil originally formed on the B-stage dielectric sheet side was measured using the evaluation sample, it was 4.5 N / cm. Only the surface layer of the exposed blackening portion of the sample for evaluation was etched with 0.1 N sulfuric acid to form a lower extraction electrode so that copper was exposed to the surface. Next, the copper foil originally formed on the B stage dielectric sheet side was etched with a resist and ferric chloride so as to form a circular pattern having a diameter of 10 mm to form an upper electrode, thereby forming a capacitor. The relative dielectric constant of the dielectric composition of the capacitor was measured and found to be 59.

Examples 2-20
Core-shell structured particles having the composition shown in Table 1 are produced in the same manner as in Example 1, capacitors are formed in the same manner as in Example 1 with the composition shown in Table 2, and the evaluation results are shown in Tables 1-2. Indicated. In Table 2, the content (% by weight) of the high dielectric constant particles is the ratio of the inorganic particles (core) in the core-shell structure particles, the curing agent, and the matrix resin (solid content only). .

Example 21
Core-shell structured particles having the composition shown in Table 1 were produced in the same manner as in Example 1, and 10 g of butyl acetate and curing agent 2PZ (manufactured by Shikoku Kasei Kogyo Co., Ltd.) were added to 100 g of the obtained core-shell structured particles. 0.39 g and 1 g of Epicoat 828 (Japan Epoxy Resin Co., Ltd.) were added and mixed to prepare a paste composition.

  Using a micro bar coater (manufactured by Inoue Kinzoku Kogyo Co., Ltd.), the paste composition was coated on a roll-shaped 18 μm thick copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd., TQ-VLP). After coating to 10 μm, the solvent was removed, and the film surface was laminated with a cover film to prepare a B-stage dielectric sheet with a roll of copper foil. The cover film was a 12 μm thick polypropylene film. The conveyance speed of the copper foil was 1.4 m / min, and the drying temperature was 120 ° C. When wound up into a roll, no unevenness or cracking occurred.

  After blackening the surface copper foil of the copper foil pasted FR-4 substrate, the surface on the dielectric sheet side of the B stage dielectric sheet with the copper foil was bonded and pressed while heating at 175 ° C. for 1 hour, An evaluation sample was produced.

  Using the evaluation sample, the peel strength of the copper foil originally formed on the B-stage dielectric sheet side was measured and found to be 2.9 N / cm. Only the surface layer of the exposed blackening portion of the sample for evaluation was etched with 0.1 N sulfuric acid to form a lower extraction electrode so that copper was exposed to the surface. Next, the copper foil originally formed on the B stage dielectric sheet side was etched with a resist and ferric chloride so as to form a circular pattern having a diameter of 10 mm to form an upper electrode, thereby forming a capacitor. The relative dielectric constant of the dielectric composition of the capacitor was measured and found to be 88.

Examples 22-49
Core-shell structured particles having the composition shown in Table 1 were produced by the same method as in Example 21, capacitors were formed by the same method as in Example 21, and the evaluation results are shown in Tables 1-2. Indicated.

Comparative Examples 1-5
Core-shell structured particles having the composition shown in Table 3 were produced in the same manner as in Example 1, capacitors were formed in the same manner as in Example 1 with the composition shown in Table 4, and the evaluation results are shown in Tables 3-4. Indicated.

Comparative Example 6
In a 250 ml polyethylene container, 20 g of butyl acetate, 13.3 g of Epicoat 828, 100 g of BTO150-S02, and 200 g of zirconia beads having an average particle diameter of 5 mm are placed and dispersed on a ball mill frame for 6 hours at a rotation speed of 200 rpm. The zirconia beads were separated with a 100 mesh stainless steel sieve to prepare a paste composition.

  Using a micro bar coater (manufactured by Inoue Kinzoku Kogyo Co., Ltd.), the paste composition was coated on a roll-shaped 18 μm thick copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd., TQ-VLP). After coating to 10 μm, the solvent was removed, and the film surface was laminated with a cover film to prepare a B-stage dielectric sheet with a roll of copper foil. The cover film was a 12 μm thick polypropylene film. The conveyance speed of the copper foil was 1.4 m / min, and the drying temperature was 120 ° C. It was confirmed that many irregularities and cracks existed when the product was rolled up.

  After blackening the surface copper foil of the copper foil-attached FR-4 substrate, the B-stage dielectric sheet with the copper foil was attached and pressed while heating at 175 ° C. for 1 hour to prepare a sample for evaluation.

  When the peel strength of the copper foil originally formed on the B-stage dielectric sheet side was measured using the evaluation sample, it was 1.7 N / cm. Only the surface layer of the exposed blackening portion of the sample for evaluation was etched with 0.1 N sulfuric acid to form a lower extraction electrode so that copper was exposed to the surface. Next, the copper foil originally formed on the B stage dielectric sheet side was etched with a resist and ferric chloride so as to form a circular pattern having a diameter of 10 mm to form an upper electrode, thereby forming a capacitor. The relative dielectric constant of the capacitor dielectric composition was measured to be 57.

Comparative Examples 7-10
A capacitor was formed with the composition shown in Table 4 in the same manner as in Comparative Example 6, and the evaluation results are shown in Table 4. In Table 4, the content (% by weight) of the high dielectric constant particles is obtained by calculating the ratio of the inorganic particles (core) to the core-shell structure particles, the curing agent, and the matrix resin (solid content only). .

The core-shell structure particle | grains of this invention are shown.

Explanation of symbols

1 Core-shell structured particle 2 Core 3 Shell

Claims (8)

Core-shell structure particles having a core containing high dielectric constant inorganic particles having a perovskite crystal structure and (a) a shell containing a resin having a polymerizable group, and having an average shell thickness of 1 nm to 50 nm The resin having a polymerizable group is formed by polymerizing a compound having at least two kinds of polymerizable groups, and the compound having at least two kinds of polymerizable groups is (1 ) a compound having an addition-polymerizable group and a condensation polymerizable group, addition polymerizable group is a carbon - selected carbon double bond, e epoxy group, oxetane group, condensation polymerization sexual polymerizable group carboxyl group, isocyanate group, those selected from a hydroxyl group, or (2) a carbon - compound having a carbon double bonds, epoxy groups and / or oxetane groups , The core is either - shell structured particle. A composition comprising the core-shell structured particles according to claim 1 and (b) a compound capable of reacting with a polymerizable group of a resin contained in the shell. The composition according to claim 2, comprising (c) a matrix resin. (C) The composition according to claim 3, wherein the matrix resin has a polymerizable group. (C) The composition according to claim 3 or 4, wherein the matrix resin contains a thermosetting resin. A dielectric composition obtained by curing the composition according to claim 2. A capacitor comprising a dielectric composition obtained by curing the composition according to claim 2 between electrodes. A high dielectric constant inorganic particle having a perovskite crystal structure is dispersed in an aqueous solvent containing a surfactant, and then mixed with a compound having two or more kinds of polymerizable groups to perform polymerization. 2. A method for producing core-shell structured particles according to 1.