TW201802215A - Inductor adhesive and inductor - Google Patents

Abstract

Provided is an inductor adhesive with which it is possible to increase humidity resistance and to suppress reduction in adhesion even when exposed to high humidity. An inductor adhesive according to the present invention includes a thermosetting compound, a thermosetting agent, an inorganic filler, and spacer particles, the spacer particles being resin particles or organic/inorganic hybrid particles, the average particle size of the spacer particles being 20-200 [mu]m, the CV value of the particle size of the spacer particles being 10% or less, and the content of the inorganic filler in 100 wt% of the adhesive being greater than 30 wt% and no more than 75 wt%.

Description

Adhesives for inductors and inductors

The present invention relates to an adhesive for an inductor. Moreover, this invention relates to the inductor using the said adhesive agent for inductors.

Use inductors in electronic devices such as mobile phones, televisions, and digital cameras. In particular, in an inductor that responds to a large current, core materials such as a ferrite core are arranged with a gap therebetween. Previously, an adhesive containing no particles or an adhesive containing particles such as glass beads was used in the gap (adhesion portion). However, it is difficult to control the thickness of the adhesive part if it is an adhesive without particles. Even if it is an adhesive containing particles such as glass beads, there is a case where the thickness of the adhesive portion is difficult to become uniform, and the yield, productivity, and reliability may be lowered. As an example of the above-mentioned adhesive, Patent Document 1 below discloses an adhesive containing nonmagnetic particles (granules). In the examples, glass beads are used as the particles. The following Patent Document 2 discloses an adhesive containing spacer particles having a CV value of 10% or less. In the examples, resin particles are used as the particles. [Prior Art Literature] [Patent Literature] [Patent Literature 1] Japanese Patent Laid-Open No. 2004-235462 [Patent Literature 2] WO2010 / 104125A1

[Problems to be Solved by the Invention] In the conventional adhesives described in Patent Documents 1 and 2, the thickness of the bonding portion (interval of the gap portion) may not be controlled with high accuracy, and the adhesiveness may be low. Furthermore, in a bonding portion (gap portion) formed by using an adhesive, the moisture resistance may be low. In addition, during the long-term reliability test subjected to thermal shock, cracks may occur in the ferrite core, or the inductance may be lower than the initial value, and the performance of the inductor may be deteriorated. In previous adhesives, it was difficult to achieve higher adhesion and higher moisture resistance at the same time. Furthermore, the long-term reliability of the conventional adhesive is deteriorated. An object of the present invention is to provide an adhesive for inductors that can have high humidity resistance and can suppress a decrease in adhesiveness even when exposed to high humidity. Another object of the present invention is to provide an inductor using the above-mentioned adhesive for inductors. [Technical means to solve the problem] According to a broad aspect of the present invention, there is provided an adhesive for an inductor, which is used for an inductor and includes a thermosetting compound, a thermosetting agent, an inorganic filler, and spacer particles. The spacer particles are resin particles or organic-inorganic mixed particles. The average particle diameter of the spacer particles is 20 μm or more and 200 μm or less. The CV value of the particle diameter of the spacer particles is 10% or less. In%, the content of the inorganic filler exceeds 30% by weight and is 75% by weight or less (hereinafter, the “adhesive for inductors” may be described as “adhesive”). In a specific aspect of the adhesive of the present invention, the above-mentioned adhesive is heated at 120 ° C for 20 minutes, and then heated at 170 ° C for 15 minutes to obtain a hardened material. At this time, the glass of the obtained hardened material is obtained. The transition point temperature is 120 ° C or higher and 210 ° C or lower. In a specific aspect of the adhesive of the present invention, after placing the above-mentioned adhesive 30 mg on the first slide and placing the second slide on the adhesive, a weight of 50 g is placed. It was placed on the second slide glass and left for 20 minutes. At this time, the number of the spacer particles in the plan view was ² or more and 1,000 or less / mm ² . In a specific aspect of the adhesive of the present invention, the content of the thermosetting agent is 0.01 parts by weight or more and 10 parts by weight or less based on 100 parts by weight of the thermosetting compound. In a specific aspect of the adhesive of the present invention, the viscosity of the adhesive at 25 ° C. is 10 Pa · s or more and 150 Pa · s or less. In a specific aspect of the adhesive of the present invention, the content of the spacer particles is 1% by weight or more and 15% by weight or less in 100% by weight of the adhesive. In a specific aspect of the adhesive of the present invention, the ratio of the content of the inorganic filler in 100% by weight of the adhesive to the content of the spacer particles in 100% by weight of the adhesive is 3 or more and Below 60. In a specific aspect of the adhesive of the present invention, the ratio of the average particle diameter of the inorganic filler to the average particle diameter of the spacer particles is 0.00005 or more and 0.1 or less. In a specific aspect of the adhesive of the present invention, the 10% K value of the spacer particles is 980 N / mm ² or more and 4900 N / mm ² or less. In a specific aspect of the adhesive of the present invention, the above-mentioned adhesive for inductors is used for bonding ferrite cores in inductors. According to a broad aspect of the present invention, there is provided an inductor including a ferrite core and a bonding portion to which the ferrite core is bonded, and a material of the bonding portion is the adhesive for the inductor. [Effects of the Invention] The adhesive for an inductor of the present invention includes a thermosetting compound, a thermosetting agent, an inorganic filler, and spacer particles. The spacer particles are resin particles or organic-inorganic mixed particles, and the average particle diameter of the spacer particles. It is 20 μm or more and 200 μm or less. The CV value of the particle diameter of the spacer particles is 10% or less. In 100% by weight of the adhesive, the content of the inorganic filler exceeds 30% by weight and is 75% by weight or less. The moisture resistance can be made high, and even if exposed to high humidity, the decrease in adhesion can be suppressed.

The details of the present invention will be described below. (Adhesive for Inductors) The adhesive for inductors (hereinafter, sometimes referred to simply as an adhesive) in the present invention is used for inductors. The adhesive of the present invention includes a thermosetting compound, a thermosetting agent, an inorganic filler, and spacer particles. In the adhesive of the present invention, the spacer particles are resin particles or organic-inorganic mixed particles. In the adhesive of the present invention, the average particle diameter of the spacer particles is 20 μm or more and 200 μm or less. In the adhesive of the present invention, the CV value of the particle diameter of the spacer particles is 10% or less. In 100% by weight of the adhesive of the present invention, the content of the inorganic filler exceeds 30% by weight and is 75% by weight or less. Since the present invention has the above-mentioned configuration, it is possible to make the moisture resistance high. For example, the adhesive portion formed by the adhesive is hard to absorb water, and even if exposed to high humidity, the decrease in adhesiveness can be suppressed. Furthermore, since the present invention has the above-mentioned configuration, the thickness uniformity of the bonding portion can be improved, excellent adhesion can be expressed, and variations in inductance can be suppressed. Furthermore, in the present invention, the thermal shock resistance can be improved, and the thermal shock resistance (long-term reliability) of the inductor can be improved. Even if the inductor is exposed to high or low temperature, or exposed to cold and heat cycles, the change in inductance can be made smaller. Furthermore, since the present invention has the above-mentioned structure, excessive wetting and diffusion of the adhesive can be suppressed, and the applicability of the adhesive is also improved. The average particle diameter of the spacer particles is 20 μm or more and 200 μm or less. From the viewpoint of further improving the adhesiveness, the average particle diameter of the spacer particles is preferably 25 μm or more, more preferably 30 μm or more, and more preferably 150 μm or less, and more preferably 130 μm or less. From the viewpoint of further improving adhesion, the ratio of the average particle diameter of the inorganic filler to the average particle diameter of the spacer particles (average particle diameter of the inorganic filler / average particle diameter of the spacer particles) is preferably 0.1 or less , More preferably 0.01 or less. From the viewpoint of further improving the moisture resistance, the above ratio (average particle diameter of the inorganic filler / average particle diameter of the spacer particles) is preferably 0.00005 or more, and more preferably 0.0005 or more. The above average particle diameter indicates a number average particle diameter. The average particle diameter of the said inorganic filler and the said spacer particle can be calculated | required by observing arbitrary 50 inorganic filler or arbitrary 50 spacer particles with an electron microscope or an optical microscope, and calculating an average value. The CV value of the particle diameter of the spacer particles is 10% or less. From the viewpoint of further improving the adhesiveness, the CV value of the particle diameter of the spacer particles is preferably 1% or more, and more preferably 5% or less. The CV value (coefficient of variation) is expressed by the following formula. CV value (%) = (ρ / Dn) × 100 ρ: Standard deviation of the particle diameter of the spacer particles Dn: The average value of the particle diameter of the spacer particles effectively improves the coating property and further increases the thickness of the bonding portion. From the standpoint of uniformity, further improving adhesion, and further suppressing the generation of pores, the viscosity of the above adhesive at 25 ° C is preferably 10 Pa · s or more, more preferably 15 Pa · s or more, and more preferably 150 Pa · s or less, more preferably 100 Pa · s or less, more preferably 70 Pa · s or less, even more preferably 40 Pa · s or less, and most preferably 35 Pa · s or less. The above viscosity (η25) can be measured, for example, using an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) at 25 ° C and 5 rpm, and a spiral viscosity meter ("PCU-MCU manufactured by Malcom Corporation"). 02V "), measured at 25 ° C and 10 rpm. When the particle diameter of the spacer particles in the adhesive is 20 μm or less, an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) can be preferably used. In the case where the particle diameter of the spacer particles in the adhesive exceeds 20 μm, a spiral viscosity meter (“PCU-02V” manufactured by Malcom) can be preferably used. From the viewpoint of further improving the thermal shock resistance, the above-mentioned adhesive is heated at 120 ° C for 20 minutes, and then heated at 170 ° C for 15 minutes to obtain a cured product. At this time, the glass transition point temperature of the obtained cured product is lower than It is preferably 120 ° C or higher, and more preferably 210 ° C or lower. When the adhesive of the present invention is hardened, heating may be performed under conditions other than the conditions of heating at 170 ° C for 15 minutes after heating at 120 ° C for 20 minutes. From the viewpoint of effectively improving the properties of moisture resistance, gap control, variation in inductance, and thermal shock resistance, the above-mentioned adhesive 30 mg was placed on the first slide and the second slide was placed on After the adhesive is applied, a 50 g weight is placed on the second glass slide and left for 20 minutes. At this time, the number of the spacer particles in the plan view is preferably 2 / mm ² or more, and more preferably It is 1,000 pieces / mm ² or less. In this observation in a plan view, the adhesive between the first and second slides was observed. From the viewpoint of effectively improving the properties of moisture resistance, gap controllability, inductance variation, and thermal shock resistance, the adhesive was heated at 120 ° C for 20 minutes, and then heated at 170 ° C for 15 minutes. The linear expansion coefficient of the hardened material obtained at this time is preferably 60 ppm or less, more preferably 50 ppm or less, still more preferably 40 ppm or less, and even more preferably 30 ppm or less. The above-mentioned adhesive can be preferably used for adhering a ferrite core in an inductor. Hereinafter, other details of the above-mentioned adhesive for inductors will be described. Thermosetting compound: The thermosetting compound contained in the adhesive is not particularly limited. The said thermosetting compound is a compound which hardens | cures by heating. These thermosetting compounds may be used alone or in combination of two or more. From the viewpoint of further improving moisture resistance and adhesiveness, it is preferable that the thermosetting compound contains an epoxy compound. From the viewpoint of further improving moisture resistance, adhesion, and heat resistance, the thermosetting compound preferably has an aromatic skeleton. Examples of the aromatic skeleton include a benzene skeleton, a naphthalene skeleton, a fluorene skeleton, a biphenyl skeleton, an anthracene skeleton, a fluorene skeleton, Skeleton, adamantane skeleton and bisphenol A skeleton. From the viewpoint of further improving moisture resistance, adhesion, and heat resistance, the aromatic skeleton is preferably a benzene skeleton, a naphthalene skeleton, or a fluorene skeleton, and more preferably a naphthalene skeleton. The aromatic skeleton may be a benzene skeleton or a naphthalene skeleton. From the viewpoint of further improving moisture resistance, adhesion, and heat resistance, the thermosetting compound is preferably a thermosetting compound having a naphthalene skeleton. From the viewpoint of further improving moisture resistance and adhesion, the content of the thermosetting compound is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and even more preferably 100% by weight of the adhesive. 1% by weight or more, particularly preferably 15% by weight or more, and more preferably 90% by weight or less, more preferably 80% by weight or less, and still more preferably 70% by weight or less. From the viewpoint of further improving moisture resistance and adhesiveness, the content of the thermosetting compound having a naphthalene skeleton is preferably 0.01% by weight or more, and more preferably 0.1% by weight or more, in 100% by weight of the adhesive. It is more preferably 1% by weight or more, particularly preferably 15% by weight or more, and more preferably 90% by weight or less, more preferably 80% by weight or less, still more preferably 70% by weight or less, and even more preferably 50% by weight or less. , Preferably 30% by weight or less. Thermosetting agent: The thermosetting agent is used to thermally harden the thermosetting compound. Examples of the thermal curing agent include an imidazole curing agent, a phenol curing agent, a thiol curing agent, an amine curing agent, an acid anhydride curing agent, a thermal cation initiator, and a thermal radical generator. These thermosetting agents may be used alone or in combination of two or more. The imidazole curing agent is not particularly limited, and examples thereof include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-cyanoethyl -2-phenylimidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-mesantriene 𠯤 and 2, 4-Diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-mesantriene 𠯤 isotricyanic acid adducts and the like. The thiol curing agent is not particularly limited, and examples thereof include trimethylolpropane tri (3-mercaptopropionate) ester, pentaerythritol tetra (3-mercaptopropionate) ester, and dipentaerythritol hexa (3-mercaptopropionate). ) Esters. In terms of effectively exhibiting the effects of the present invention, the solubility parameter of the thiol hardener is preferably 9.5 or more, and more preferably 12 or less. The above solubility parameters are calculated by the Fedors method. For example, the solubility parameter of trimethylolpropane tris (3-mercaptopropionate) ester is 9.6, and the solubility parameter of dipentaerythritol hexa (3-mercaptopropionate) ester is 11.4. The amine hardener is not particularly limited, and examples thereof include hexamethylenediamine, octamethylenediamine, decamethylenediamine, and 3,9-bis (3-aminopropyl) -2. , 4,8,10-tetraspiro [5.5] undecane, bis (4-aminocyclohexyl) methane, m-phenylenediamine and diaminodiphenylphosphonium. Examples of the thermal cationic initiator include a fluorene-based cation hardener, an oxonium-based cation hardener, and a fluorene-based cation hardener. Examples of the fluorene-based cationic hardener include bis (4-thirdbutylphenyl) fluorene hexafluorophosphate and the like. Examples of the oxonium-based cation hardener include trimethyloxonium tetrafluoroborate and the like. Examples of the fluorene-based cation hardener include tri-p-tolyl hexafluorophosphate and the like. The thermal radical generator is not particularly limited, and examples thereof include an azo compound and an organic peroxide. Examples of the azo compound include azobisisobutyronitrile (AIBN) and the like. Examples of the organic peroxide include di-tert-butyl peroxide and methyl ethyl ketone peroxide. The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent is preferably 0.01 part by weight or more, more preferably 1 part by weight or more, and more preferably 200 parts by weight or less, and more preferably 100 parts by weight or less with respect to 100 parts by weight of the thermosetting compound. It is more preferably 75 parts by weight or less, particularly preferably 50 parts by weight or less, and most preferably 10 parts by weight or less. When the content of the thermosetting agent is at least the above lower limit, it is easy to sufficiently harden the adhesive. If the content of the thermosetting agent is equal to or less than the above-mentioned upper limit, after the hardening, the remaining thermosetting agent that does not participate in hardening is unlikely to remain, and the heat resistance of the adhesive part becomes higher. Spacer particles: Examples of the spacer particles include resin particles, inorganic particles other than metal particles, organic-inorganic mixed particles, and metal particles. In the present invention, the spacer particles are resin particles or organic-inorganic mixed particles. The spacer particles may be core-shell particles having a core and a shell arranged on a surface of the core. The core may be an organic core. The shell may be an inorganic shell. When stress is applied to the bonding portion, from the viewpoint of reducing stress and maintaining high adhesion, spacer particles other than metal particles are preferred, and resin particles and inorganic particles other than metal particles are more preferred. Or organic-inorganic mixed particles. In terms of a more excellent effect of the present invention, in the present invention, resin particles or organic-inorganic mixed particles are used. The spacer particles are preferably resin particles formed of a resin. When the spacer particles are resin particles, when stress is applied to the bonding portion, the stress can be relaxed and the adhesiveness can be maintained high. As the resin for forming the resin particles, various organic substances can be preferably used. Examples of the resin for forming the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; polymethacrylic acid Acrylic resins such as methyl ester and polymethyl acrylate; polyalkylene terephthalate, polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, Melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyfluorene, polyphenylene ether, polyacetal, polyimide, polyimide, imine, polyimide Ether ether ketone, polyether fluorene, and polymers obtained by polymerizing one or two or more kinds of polymerizable monomers having an ethylenically unsaturated group. Since the hardness of the spacer particles can be easily controlled to a preferable range, the resin used to form the resin particles is preferably one or two or more polymerizable monomers having a plurality of ethylenically unsaturated groups. Polymerized polymer. When polymerizing a polymerizable monomer having an ethylenically unsaturated group to obtain the resin particles, examples of the polymerizable monomer having an ethylenically unsaturated group include a non-crosslinkable monomer and a crosslinkable monomer. body. Examples of the non-crosslinkable monomer include styrene-based monomers such as styrene and α-methylstyrene; and carboxyl-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride Body; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) Lauryl acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, iso (meth) acrylate, etc. Ester compounds; 2-hydroxyethyl (meth) acrylate, glyceryl (meth) acrylate, polyoxyethylene (meth) acrylate, glycidyl (meth) acrylate, etc. (meth) acrylic acid Ester compounds; nitrile group-containing monomers such as (meth) acrylonitrile; vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; vinyl acetate, vinyl butyrate, lauric acid Vinyl acid esters, vinyl stearate and other acid vinyl ester compounds; unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; trifluoro (meth) acrylate Ester, (meth) acrylate, pentafluoro methacrylate, vinyl chloride, vinyl fluoride, chlorine halogen-containing monomers such as styrene and the like. Examples of the crosslinkable monomer include tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, and tetramethylolmethane di (meth) acrylate. , Trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glyceryl tri (meth) acrylate, glyceryl di (meth) acrylate Ester, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, (poly) tetramethylene glycol di (meth) acrylate, 1,4-butane Polyfunctional (meth) acrylate compounds such as diol di (meth) acrylate; triallyl (iso) cyanurate, triallyl trimellitate, divinylbenzene, diallyl phthalate Esters, diallyl allylamine, diallyl ether, γ- (meth) acryl methoxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane and other silane-containing monomers体 等。 Body and so on. The resin particles can be obtained by polymerizing the polymerizable monomer having an ethylenically unsaturated group by a known method. Examples of the method include a method of performing suspension polymerization in the presence of a radical polymerization initiator; and a method of using a non-crosslinked seed particle to swell the monomer together with the radical polymerization initiator to perform polymerization. Wait. When the spacer particles are inorganic particles or organic-inorganic mixed particles other than metal particles, examples of the inorganic substance used to form the spacer particles include silicon dioxide and carbon black. The inorganic substance is preferably not a metal. The particles formed by the above-mentioned silicon dioxide are not particularly limited, and examples thereof include particles formed by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles. Then, it is obtained by baking as necessary. Examples of the organic-inorganic mixed particles include organic-inorganic mixed particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin. From the viewpoint of further improving adhesion and reliability, the compression elastic modulus (10% K value) when the spacer particles are compressed by 10% is preferably 980 N / mm ² or more, and more preferably 1200 N / mm ² or more, and preferably 4 900 N / mm ² or less, and more preferably 3000 N / mm ² or less. The said 10% K value of the said spacer particle can be measured as follows. Using a micro compression tester, the spacer particles were compressed at the end face of a smooth indenter of a cylinder (50 μm in diameter, made of diamond) at 25 ° C and a maximum test load of 90 mN for 30 seconds. The load value (N) and compression displacement (mm) at this time were measured. Based on the obtained measured values, the above-mentioned compressive elastic modulus can be obtained by the following formula. As the micro compression tester, for example, "Fischerscope H-100" manufactured by Fischer Corporation is used. K value (N / mm ² ) = (3/2 ^1/2 ) ・ F ・ S ^-3/2・ R ^-1/2 F: load value when spacer particles are compressed and deformed by 10% (N) S: interval Compression displacement (mm) at 10% compression deformation of material particles R: Radius (mm) of spacer particles From the viewpoint of further improving the moisture resistance and adhesion and further improving the uniformity of the thickness of the bonding portion, the above The content of the spacer particles in 100% by weight of the adhesive is preferably 1% by weight or more, more preferably 2% by weight or more, further preferably more than 5% by weight, and more preferably 15% by weight or less, more preferably 12% by weight or less. Inorganic filler: Examples of the material of the inorganic filler include silicon dioxide, talc, clay, mica, hydrotalcite, aluminum oxide, magnesium oxide, aluminum hydroxide, aluminum nitride, and boron nitride. From the viewpoint of further improving the moisture resistance, the inorganic filler is preferably silicon dioxide or aluminum oxide, more preferably silicon dioxide, and still more preferably fused silicon dioxide. By using silicon dioxide, the thermal expansion rate of the bonding portion becomes lower, and then the reliability becomes higher. From the viewpoint of further improving the moisture resistance, the inorganic filler is preferably a surface-treated product treated with a coupling agent. Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent. From the viewpoint of further improving the adhesiveness, the inorganic filler is preferably a surface-treated product treated with a silane coupling agent. Examples of the silane coupling agent include phenylsilane, vinylsilane, aminesilane, imidazolesilane, and epoxysilane. From the viewpoint of further improving the moisture resistance, phenylsilane is preferred. In the 100% by weight of the adhesive, the content of the inorganic filler exceeds 30% by weight and is 75% by weight or less. From the viewpoint of further improving the moisture resistance, the content of the inorganic filler in 100% by weight of the adhesive is preferably more than 35% by weight, and more preferably 40% by weight or more. From the viewpoint of further improving the adhesiveness, the content of the inorganic filler is preferably 70% by weight or less, more preferably 65% by weight or less, and still more preferably 60% by weight or less. When the content of the inorganic filler is more than 35% by weight in 100% by weight of the adhesive, the moisture resistance becomes considerably high. From the viewpoint that the balance is better to improve both the adhesiveness and the moisture resistance, the content of the inorganic filler in 100% by weight of the adhesive is relative to the content of the spacer particles in 100% by weight of the adhesive. The ratio (content of inorganic filler / content of spacer particles) is preferably 3 or more, more preferably 4 or more, and more preferably 60 or less, and more preferably 30 or less. Other components: The said adhesive may contain a photocurable component, and may also contain a photocurable compound and a photopolymerization initiator. From the viewpoint of further improving the adhesiveness, the above-mentioned adhesive preferably contains a coupling agent. Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent. From the viewpoint of further improving the adhesiveness, the above-mentioned adhesive preferably contains a silane coupling agent. Examples of the silane coupling agent include phenylsilane, vinylsilane, aminesilane, imidazolesilane, and epoxysilane. From the viewpoint of further improving the adhesiveness, the content of the coupling agent is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and more preferably 2% by weight or less in 100% by weight of the adhesive. It is preferably 1% by weight or less. From the viewpoints of effectively improving coating properties, further increasing the thickness uniformity of the adhesive portion, further improving the adhesiveness, and further suppressing the generation of voids, the adhesive preferably contains a thixotropy imparting agent. Examples of the thixotropy-imparting agent include metal particles, calcium carbonate, fumed silica, alumina, boron nitride, aluminum nitride, and inorganic particles such as aluminum borate. From the viewpoint of effectively improving the coating property, further increasing the uniformity of the thickness of the adhesive portion, further improving the adhesiveness, and further suppressing the generation of voids, the content of the thixotropy imparting agent is 100% by weight of the adhesive It is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, and more preferably 10% by weight or less, and even more preferably 5% by weight or less. The above-mentioned adhesives may include fillers, extenders, softeners, plasticizers, polymerization catalysts, hardening catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, and lubricants as required. , Antistatic agents and flame retardants and other additives. (Inductor) The inductor of the present invention includes a ferrite core and a bonding portion to which the ferrite core is bonded. In the inductor of the present invention, the material of the bonding portion is the bonding agent for the inductor. The said adhesive part is a hardened | cured material of the said adhesive agent for inductors. The said adhesive part is formed by hardening the said adhesive agent for inductors. Preferably, the ferrite core is disposed on a surface of both sides of the bonding portion facing each other. It is preferable that the ferrite core has a gap due to the bonding portion. FIG. 1 is a cross-sectional view schematically showing an inductor using an adhesive for inductors according to an embodiment of the present invention. The inductor 1 shown in FIG. 1 includes a ferrite core 11, a ferrite core 12, and a bonding portion 13. The inductor 1 includes a plurality of ferrite cores (a ferrite core 11 and a ferrite core 12). The inductor 1 includes a coil core for a transformer component. The ferrite core 11 is an E-type ferrite core. The ferrite core 12 is an I-type ferrite core. Among the three convex portions of the E-type ferrite core 11, the front ends of the two convex portions on the outside face the side surfaces of the I-type ferrite core 12, with a gap therebetween. A bonding portion 13 is arranged in the gap. The material of this bonding portion 13 is the above-mentioned adhesive for inductors. In this embodiment, the thickness of the bonding portion 13 is the same as the particle diameter of the spacer particles included in the bonding agent 13. The spacer particles are in contact with both the ferrite core 11 and the ferrite core 12. Hereinafter, the present invention will be specifically described with examples and comparative examples. The present invention is not limited to the following examples. Prepare the following materials. Thermosetting compound 1: Resorcinol type epoxy compound, "Epolight TDG-LC" manufactured by Kyoeisha Chemical Co., Ltd. Thermosetting compound 2: Bisphenol F type epoxy compound, "EXA-830CRP" manufactured by DIC Thermal Hardenable compound 3: Naphthalene type epoxy compound, "HP-4032D" manufactured by DIC Corporation. Thermosetting compound 4: Bisphenol A type epoxy compound, "EXA-850CRP" manufactured by DIC. Thermosetting compound 5: Naphthalene type. Epoxy compound, "HP-4710" thermosetting compound 6 manufactured by DIC Corporation: 茀 -type epoxy compound, "OGSOL PG-100" manufactured by Osaka Gas Chemicals Co., Ltd. Thermal curing agent 1: Imidazole hardening accelerator, Soda Corporation of Japan "TEP-2E4MZ" manufactured by thermosetting agent 2: Imidazole hardening accelerator, "2MZA-PW" manufactured by Shikoku Chemical Industry Co., Ltd. Coupling agent: Silane coupling agent, "KBM-573" made by Shin-Etsu Chemical Industry Co., Ltd. Agent: "PM-20L" inorganic filler manufactured by Tokuyama Corporation 1: Silicon dioxide, average particle diameter of 1 μm, "SE4050-SPE" inorganic filler manufactured by Admatechs Corporation: Silicon dioxide, average particle diameter of 3.8 μm, Dragon Made by Mori "EXR-4" spacer 1 average particle size: 20 μm, CV value of 5%, 10% K value is 3600 N / mm ^2, manufactured by Sekisui Chemical Co.'s "SP-220" resin spacer particles 2: average particle Diameter 150 μm, CV value 7%, 10% K value 2000 N / mm ² , “SP-L150” manufactured by Sekisui Chemical Industries, resin particle spacer 3: average particle size 50 μm, CV value 5%, 10% K value 3800 N / mm ² , "SP-250" manufactured by Sekisui Chemical Industry Co., Ltd., resin particle spacer 4: average particle size 200 μm, CV value 7%, 10% K value 3900 N / mm ² , Sekisui Chemical Industry "GS-L200" manufactured by the company, resin particles (Example 1) (1) Preparation of adhesives for inductors According to the composition in Table 1, each material other than the spacer was stirred and mixed by a revolution mixer, thereby An adhesive composition was obtained. In the obtained adhesive composition, spacer particles were prepared according to the composition shown in Table 1, and the mixture was stirred and mixed using a rotation-revolution mixer to prepare an adhesive for an inductor. (2) Production of inductor Fill the obtained inductor with an adhesive into a 10 mL syringe (manufactured by Wuzhi Hi-tech Co.), and install a precision nozzle (made by Wuzhi Hi-tech Co., Ltd. at the front end of the syringe. When the particle diameter is less than 100 μm, it is 0.3 mm, and when the spacer particle diameter is 100 μm or more, it is 0.6 mm. Using a dispenser device ("SHOT MASTER300" manufactured by Takeshi Hi-Tech Co., Ltd.), It is coated on an I-type magnetic core and bonded to an E-type magnetic core, and then hardened by a reflow furnace to obtain an inductor. (3) Preparation of samples for moisture resistance evaluation The obtained adhesive for the inductor was filled into a 10 mL syringe (manufactured by Wuzhi Hi-tech Co., Ltd.), and a precision nozzle (manufactured by Wuzhi Hi-tech Co., Ltd. was installed at the front end of the nozzle. Diameter 0.3 mm), using a dispenser device ("SHOT MASTER300" manufactured by Takeyo Hi-Tech Co., Ltd.), bonding 5 ferrite sheets of the same length as the inductor, 3 mm long, 3 mm wide, and 0.3 mm thick, and A ferrite sheet of the same length as the inductor, 20 mm in length, 20 mm in width, and 0.3 mm in thickness, was hardened in a reflow furnace to obtain a sample for evaluating moisture resistance. (Examples 2 to 16, Comparative Examples 1, 2) Except for changing the types and blending amounts of the blending components as shown in Tables 1 and 2, an adhesive for inductors and an inductor were obtained in the same manner as in Example 1. And samples for moisture resistance evaluation. (Evaluation) (1) When the particle diameter of the spacer particles having a viscosity in the adhesive is 20 μm or less, use an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) at 25 ° C and 5 rpm. The viscosity (η25) of the adhesive at 25 ° C was measured under the conditions. When the particle diameter of the spacer particles in the adhesive exceeds 20 μm, use a spiral viscosity meter ("PCU-02V" manufactured by Malcom) to measure the adhesive at 25 ° C at 25 ° C and 10 rpm. Viscosity (η25). (2) Evaluation of applicability The applicability was evaluated using a dispenser device ("SHOT MASTER 300" manufactured by Takeshi Hi-Tech Co., Ltd.). The coating conditions were fixed under a precision nozzle (made by Takeyo Hi-Tech Co., Ltd., the inner diameter of the tip of the nozzle is 0.3 mm) and the discharge conditions (temperature: 25 ° C, discharge pressure: 0.3 Mpa). The coating was applied to a glass substrate to evaluate the coating. Cloth. The applicability was judged by the following criteria. [Critical criteria for applicability] ○ ○: Successful application without blurring or sagging ○: Slight blurring or sagging △: Although there are no coating cracks, large blurring or sagging occurs ×: Occurrence The coating is cracked, or cannot be coated at all. (3) Particle dispersibility (pcs / mm ² ) Put 30 mg of the adhesive on the first slide, and place the second slide on the adhesive. The weight of g was placed on the above-mentioned second glass slide and left for 20 minutes. After being left to stand, the number of spacer particles per 1 mm ^{2 in} plan view was measured using an optical microscope. (4) Measurement of glass transition point temperature (Tg) The adhesive was heated at 120 ° C for 20 minutes, and then heated at 170 ° C for 15 minutes to harden to obtain a cured product. Using a viscoelasticity measuring machine (manufactured by IT Meter and Control Co., Ltd.), the tan δ of the hardened product obtained was measured under conditions of a temperature increase rate of 10 ° C./minute and a clamping width of 20 mm and 5 Hz. The temperature at the peak of Tan δ was taken as the glass transition temperature. (5) Linear expansion coefficient The adhesive was heated at 120 ° C for 20 minutes, and then heated at 170 ° C for 15 minutes to harden to obtain a cured product. Using TMA / SS6000 (manufactured by Seiko Instruments), the linear expansion coefficient of the obtained hardened material was measured under conditions of heating from room temperature (25 ° C) to 250 ° C at a temperature increase rate of 5 ° C / min. (6) Moisture resistance: The samples after the obtained samples for humidity resistance evaluation were placed in an oven at 85 ° C and 85% humidity for 24 hours, and the samples for evaluation of humidity resistance were placed at room temperature The adhesion of the sample was measured. The wafer shear strength was measured by a wafer shear strength tester "Dage series 4000" manufactured by Dage Corporation to evaluate the moisture resistance. The moisture resistance was determined by the following criteria. [Judgment Criteria for Moisture Resistance] ○ ○: Adhesion force of samples placed under high temperature and high humidity is 90% or more of adhesion force of samples placed under normal temperature ○: Adhesion force of samples placed under high temperature and high humidity The adhesion force of samples placed at normal temperature is more than 80% and less than 90% △: The adhesion force of samples placed at high temperature and humidity is more than 70% and less than 80% of adhesion force of samples placed at normal temperature ×: Adhesion force of samples placed under high temperature and humidity does not reach 70% of adhesion force of samples placed under normal temperature (7) Gap controllability In the obtained inductor, a laser displacement meter (manufactured by KEYENCE Corporation) is used "KS-1100"), and the distance between the gaps and the distance between the gaps after the hardening were measured by 3σ (σ; standard deviation). The gap controllability was evaluated based on the deviation 3σ of the distance between the gaps / the value X of the distance between the gaps after hardening. The gap controllability was judged on the basis of the following. [Judging criteria for gap controllability] ○: Value X is less than 0.1 ○: Value X is 0.1 or more and less than 0.2 △: Value X is 0.2 or more and less than 0.4 ×: Value X is 0.4 or more (8) Inductance Deviation was measured for the inductance of the 20 obtained inductors, and the deviation was evaluated. The deviation of the inductance is determined on the basis of the following. [Judgment Criteria for Inductance Deviation] ○ ○: The CV value of the inductance is less than 5% ○: The CV value of the inductance is 5% or more and less than 10% △: The CV value of the inductance is 10% or more and less than 15% × : The CV value of the inductor is 15% or more. (9) Thermal shock resistance 1 (long-term reliability) The obtained inductor was placed at a temperature of 125 ° C for 30 minutes and 30 minutes at -40 ° C. Under 500 cycles of change. Thereafter, the change rate of the inductance was measured. The characteristic change rate means a deviation ratio of an inductance caused by peeling on a bonding surface due to thermal shock or a change in a distance between gaps. [Judgment criteria for thermal shock resistance 1] ○: Change rate from the initial value of the inductance is less than 10% ○: Change rate from the initial value of the inductance is 10% or more and less than 20% △: and The rate of change between the initial value of the inductor is more than 20% and less than 30% ×: The rate of change from the initial value of the inductance is more than 30% (10) Thermal shock resistance 2 (long-term reliability) The inductor was placed in an environment that gave a temperature change of 500 cycles of 30 minutes at a high temperature of 150 ° C and 30 minutes at a low temperature of -50 ° C. Thereafter, the change rate of the inductance was measured. [Criterion Criteria for Thermal Shock Resistance 2] ○: The change rate from the initial value of the inductance is less than 10% ○: The change rate from the initial value of the inductance is 10% or more and less than 20% △: and The change rate from the initial value of the inductor is 20% or more and less than 30% ×: The change rate from the initial value of the inductance is 30% or more. Details and results are shown in Tables 1 and 2 below. [Table 1] [Table 2]

1‧‧‧ inductor
11‧‧‧ Ferrite Core (Type E)
12‧‧‧ Ferrite Core (Type I)
13‧‧‧ Follow-up

FIG. 1 is a cross-sectional view schematically showing an inductor using an adhesive for inductors according to an embodiment of the present invention.

1‧‧‧ inductor

11‧‧‧ Ferrite Core (Type E)

12‧‧‧ Ferrite Core (Type I)

13‧‧‧ Follow-up

Claims (11)

An adhesive for inductors, which is used for inductors, and includes a thermosetting compound, a thermosetting agent, an inorganic filler, and spacer particles. The spacer particles are resin particles or organic-inorganic mixed particles. The average particle diameter is 20 μm or more and 200 μm or less. The CV value of the particle diameter of the spacer particles is 10% or less. In 100% by weight of the adhesive, the content of the inorganic filler exceeds 30% by weight and is 75% by weight. the following. For example, the adhesive for inductors according to claim 1, wherein when the above adhesive is heated at 120 ° C for 20 minutes and then heated at 170 ° C for 15 minutes to obtain a hardened material, the glass transition point temperature of the obtained hardened material is 120 Above ℃ and below 210 ℃. If the adhesive for inductors of item 1 or 2 is requested, after placing the above-mentioned adhesive 30 mg on the first slide and placing the second slide on the above adhesive, put a 50 g weight on The second glass slide was left for 20 minutes. At this time, the number of the spacer particles in the plan view was ² or more and 1,000 or less / mm ² . The adhesive for inductors according to claim 1 or 2, wherein the content of the thermosetting agent is 0.01 part by weight or more and 10 parts by weight or less based on 100 parts by weight of the thermosetting compound. For example, the adhesive for inductors of claim 1 or 2, wherein the viscosity of the above adhesive at 25 ° C is 10 Pa · s or more and 150 Pa · s or less. The adhesive for inductors according to claim 1 or 2, wherein the content of the spacer particles is 1% by weight or more and 15% by weight or less in 100% by weight of the adhesive. The adhesive for inductors according to claim 1 or 2, wherein the ratio of the content of the inorganic filler in 100% by weight of the adhesive to the content of the spacer particles in 100% by weight of the adhesive is 3 or more and 60 or less . The adhesive for inductors according to claim 1 or 2, wherein the ratio of the average particle diameter of the inorganic filler to the average particle diameter of the spacer particles is 0.00005 or more and 0.1 or less. For example, the adhesive for inductors of claim 1 or 2, wherein the 10% K value of the spacer particles is 980 N / mm ² or more and 4900 N / mm ² or less. The adhesive for inductors as claimed in item 1 or 2 is used for the bonding of ferrite cores in inductors. An inductor includes a ferrite core and a bonding portion to which the ferrite core is bonded, and the material of the bonding portion is an adhesive for an inductor as claimed in claim 1 or 2.