JP7086657B2 - Resin composition and inductor - Google Patents

Description

The present invention relates to a resin composition containing a thermosetting compound and a thermosetting agent. The present invention also relates to an inductor using the above resin composition.

Conventionally, in various electronic components, a resin composition has been used for adhering members to each other and coating the surface of the members.

Inductors are also known as electronic components. Inductors are used in mobile phones, televisions, digital cameras and the like. In particular, in an inductor that can handle a large current, a core material such as a ferrite core is arranged with a gap. Conventionally, an adhesive containing no particles (resin composition) or an adhesive containing particles such as glass beads (resin composition) has been used for the gap (adhesive portion).

As an example of the above resin composition, Patent Document 1 below discloses a one-component curable resin composition containing a specific epoxy resin. Patent Document 1 describes that both low-temperature curability and ensuring adhesive strength can be achieved at the same time.

The following Patent Document 2 discloses an adhesive containing non-magnetic particles (grains). This adhesive may be a curable adhesive.

WO2015 / 060440A1 Japanese Unexamined Patent Publication No. 2004-235462

High heat resistance is required for the cured product of the resin composition used for electronic parts. However, in a thermosetting compound having high heat resistance after curing, the viscosity of the resin composition before curing may be high. With conventional resin compositions, it is difficult to achieve both high heat resistance and good coatability.

Further, with the conventional resin composition, the adhesive strength of the cured product to the member to be coated at a high temperature cannot be sufficiently increased, and the adhesiveness of the cured product to the member to be coated at a high temperature may be lowered. ..

An object of the present invention is to have an appropriately low viscosity and excellent coatability, a high glass transition temperature of a cured product and excellent heat resistance, and to improve the adhesion of the cured product to a member to be coated at a high temperature. It is to provide a resin composition which can be used. Another object of the present invention is to provide an inductor using the above resin composition.

According to a broad aspect of the present invention, it contains a bisphenol type epoxy compound, a polyfunctional epoxy compound different from the bisphenol type epoxy compound, and a heat curing agent, and has a viscosity at 25 ° C. of 40 Pa · s or less and 190 ° C. A resin composition is provided in which the glass transition temperature of the cured product is 170 ° C. or higher when the cured product is obtained by curing for 30 minutes.

In certain aspects of the resin composition according to the invention, the polyfunctional epoxy compound has a naphthalene skeleton, a fluorene skeleton, a glycoluryl skeleton, a dicyclopentadiene skeleton or a phenol novolac skeleton.

In certain aspects of the resin composition according to the present invention, the bisphenol type epoxy compound is a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, or a bisphenol E type epoxy compound.

In a specific aspect of the resin composition according to the present invention, when a cured product is obtained by curing at 190 ° C. for 30 minutes, the weight loss of the cured product with respect to the resin composition before curing is 5% by weight or less. ..

In a specific aspect of the resin composition according to the present invention, the ratio of the content of the polyfunctional epoxy compound to the content of the bisphenol type epoxy compound is 1/9 or more and 4/6 or less on a weight basis. be.

In a specific aspect of the resin composition according to the present invention, when a cured product is obtained by curing at 190 ° C. for 30 minutes, the 5% weight loss temperature by thermogravimetric analysis of the cured product is 360 ° C. or higher.

In certain aspects of the resin composition according to the invention, the resin composition comprises spacer particles.

In certain aspects of the resin composition according to the present invention, the resin composition is an adhesive for electronic components.

In certain aspects of the resin composition according to the present invention, the resin composition is used for bonding a ferrite core.

In certain aspects of the resin composition according to the present invention, the resin composition is used for bonding a ferrite core in an inductor.

According to a broad aspect of the present invention, there is provided an inductor having a ferrite core and an adhesive portion to which the ferrite core is adhered, and the material of the adhesive portion is the resin composition described above.

The resin composition according to the present invention contains a bisphenol type epoxy compound, a polyfunctional epoxy compound different from the bisphenol type epoxy compound, and a heat curing agent. The resin composition according to the present invention has a viscosity at 25 ° C. of 40 Pa · s or less. In the resin composition according to the present invention, when a cured product is obtained by curing at 190 ° C. for 30 minutes, the glass transition temperature of the cured product is 170 ° C. or higher. Since the resin composition according to the present invention has the above-mentioned structure, it has an appropriately low viscosity and excellent coatability, a cured product having a high glass transition temperature and excellent heat resistance, and under high temperature. It is possible to improve the adhesion of the cured product to the member to be coated.

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

Hereinafter, the details of the present invention will be described.

(Resin composition)
The resin composition according to the present invention contains a thermosetting compound and a thermosetting agent. The resin composition according to the present invention contains, as the thermosetting compound, a bisphenol type epoxy compound and a polyfunctional epoxy compound different from the bisphenol type epoxy compound. The viscosity of the resin composition according to the present invention at 25 ° C. is 40 Pa · s or less. The viscosity of the resin composition according to the present invention is relatively low and excellent in coatability. When the resin composition according to the present invention is cured at 190 ° C. for 30 minutes to obtain a cured product, the glass transition temperature of the cured product is 170 ° C. or higher. From the viewpoint of enhancing the adhesion of the cured product to the member to be coated under high temperature, the glass transition temperature of the cured product is preferably 180 ° C. or higher, more preferably 190 ° C. or higher.

In the present invention, the viscosity is moderately low, the coating property is excellent, the glass transition temperature is high, and the heat resistance is excellent. In the present invention, since the above-mentioned compounding components are combined, the viscosity can be effectively lowered and the glass transition temperature can be effectively raised. Further, in the present invention, since the above configuration is adopted, the adhesion of the cured product to the member to be coated at a high temperature can be sufficiently enhanced. In the present invention, the adhesive strength of the cured product to the member to be coated at a high temperature can be sufficiently increased, so that the adhesion of the cured product to the member to be coated at a high temperature is improved. Further, since the resin composition according to the present invention has an appropriately low viscosity, the thickness of the cured product can be uniformly controlled when it is applied onto the member to be coated. For example, when a cured product is placed between the members, the gap controllability can be improved. When bonding a ferrite core in an inductor, a core material such as a ferrite core needs to be arranged with a gap. In such a case, it is of high technical significance to apply the present invention to enhance the gap controllability.

From the viewpoint of further improving the gap controllability, the viscosity (η25) of the resin composition at 25 ° C. is preferably 40 Pa · s or less, more preferably 30 Pa · s or less, still more preferably 20 Pa · s or less. Is.

The viscosity (η25) is determined by using, for example, an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.) under the conditions of 25 ° C. and 5 rpm, and a spiral viscometer (“PCU-02V” manufactured by Malcolm Co., Ltd.). It can be measured at 25 ° C. and 10 rpm. When the particle size of the spacer particles in the resin composition is 20 μm or less, an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.) is preferably used. When the particle size of the spacer particles in the resin composition exceeds 20 μm, a spiral viscometer (“PCU-02V” manufactured by Malcolm) is preferably used.

From the viewpoint of further improving heat resistance, when the resin composition is cured at 190 ° C. for 30 minutes to obtain a cured product, the temperature at which the cured product is reduced by 5% by thermogravimetric analysis (TGA). Is preferably 360 ° C. or higher, more preferably 380 ° C. or higher, still more preferably 390 ° C. or higher. The 5% weight loss temperature is the temperature at which the weight of the cured product is reduced by 5% by weight.

Specifically, the 5% weight loss temperature can be measured under the condition of a temperature rise rate of 10 ° C./min using a differential thermogravimetric simultaneous measuring device (“TG-DTA6200” manufactured by Seiko Instruments) or the like. ..

Next, the details of the components contained in the resin composition will be described.

Thermosetting compound:
The resin composition contains, as a thermosetting compound, a bisphenol type epoxy compound and a polyfunctional epoxy compound different from the bisphenol type epoxy compound. The polyfunctional epoxy compound in the resin composition according to the present invention does not contain a bisphenol type epoxy compound. The polyfunctional epoxy compound has two or more epoxy groups. Only one kind of the bisphenol type epoxy compound may be used, or two or more kinds thereof may be used in combination. Only one kind of the polyfunctional epoxy compound may be used, or two or more kinds thereof may be used in combination.

Examples of the bisphenol type epoxy compound include bisphenol A type epoxy compound, bisphenol F type epoxy compound, bisphenol E type epoxy compound, and bisphenol S type epoxy compound.

The bisphenol type epoxy compound is preferably a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, or a bisphenol E type epoxy compound, and more preferably a bisphenol F type epoxy compound or a bisphenol E type epoxy compound. It is more preferable that it is a bisphenol E type epoxy compound. The bisphenol type epoxy compound may be a bisphenol F type epoxy compound. By satisfying the above-mentioned preferable embodiment, the bisphenol type epoxy compound can further improve the glass transition temperature. Only one kind of these preferable bisphenol type epoxy compounds may be used, or two or more kinds thereof may be used in combination.

Examples of the polyfunctional epoxy compound include a naphthalene type epoxy compound, a fluorene type epoxy compound, a glycoluril type epoxy compound, a dicyclopentadiene type epoxy compound, a phenol novolac type epoxy compound, and a resorcinol type epoxy compound.

The polyfunctional epoxy compound preferably has a naphthalene skeleton, a fluorene skeleton, a glycoluryl skeleton, a dicyclopentadiene skeleton, a phenol novolac skeleton or a resorcinol skeleton, and has a naphthalene skeleton, a fluorene skeleton, a glycoluryl skeleton, or a dicyclopentadiene skeleton. It is more preferable to have. The polyfunctional epoxy compound can further improve the glass transition temperature by satisfying the above-mentioned preferred embodiments. Only one of these preferred polyfunctional epoxy compounds may be used, or two or more thereof may be used in combination.

The content of the thermosetting compound in 100% by weight of the resin composition is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, still more preferably 1% by weight or more, and particularly preferably 15%. It is 0% by weight or more, preferably 90% by weight or less, more preferably 80% by weight or less, still more preferably 70% by weight or less. The total content of the bisphenol type epoxy compound and the polyfunctional epoxy compound in 100% by weight of the resin composition is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, still more preferably. It is 1% by weight or more, particularly preferably 15% by weight or more. The total content of the bisphenol type epoxy compound and the polyfunctional epoxy compound in 100% by weight of the resin composition is preferably 90% by weight or less, more preferably 80% by weight or less, still more preferably 70% by weight or less. Is. When the content of the thermosetting compound and the total content of the bisphenol type epoxy compound and the polyfunctional epoxy compound are at least the above lower limit, the glass transition temperature becomes even better. When the content of the thermosetting compound and the total content of the bisphenol type epoxy compound and the polyfunctional epoxy compound are not more than the above upper limit, the glass transition temperature becomes even better.

From the viewpoint of further improving the gap controllability, the ratio of the content of the polyfunctional epoxy compound to the content of the bisphenol type epoxy compound (content of the polyfunctional epoxy compound / content of the bisphenol type epoxy compound). Is preferably 1/9 or more, preferably 4/6 or less, and more preferably 3/7 or less on a weight basis.

Thermosetting agent:
The thermosetting agent heat-cures the thermosetting compound. Examples of the heat curing agent include an imidazole curing agent, a phenol curing agent, an amine curing agent, an acid anhydride curing agent, a thermal cation initiator, a thermal radical generator and the like. Only one type of the thermosetting agent may be used, or two or more types may be used in combination.

The above-mentioned imidazole curing agent is not particularly limited. Examples of the imidazole curing agent include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, and 2,4-diamino-6. -[2'-Methylimidazolyl- (1')]-ethyl-s-triazine and 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine isocyanuric acid adduct And so on.

The amine curing agent is not particularly limited. Examples of the amine curing agent include hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraspiro [5.5] undecane and bis (4). -Aminocyclohexyl) methane, metaphenylenediamine, diaminodiphenyl sulfone and the like.

The thermal cation initiator is not particularly limited. Examples of the thermal cation initiator include an iodonium-based cation curing agent, an oxonium-based cation curing agent, and a sulfonium-based cation curing agent. Examples of the iodine-based cationic curing agent include bis (4-tert-butylphenyl) iodinenium hexafluorophosphate and the like. Examples of the oxonium-based cationic curing agent include trimethyloxonium tetrafluoroborate. Examples of the sulfonium-based cationic curing agent include tri-p-tolylsulfonium hexafluorophosphate.

The thermal radical generator is not particularly limited. Examples of the thermal radical generator include azo compounds and organic peroxides. 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. With respect to 100 parts by weight of the thermosetting compound, the content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, preferably 200 parts by weight or less, and more preferably. It is 100 parts by weight or less, 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. The content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, based on 100 parts by weight of the total of the bisphenol type epoxy compound and the polyfunctional epoxy compound. The content of the thermosetting agent is preferably 200 parts by weight or less, more preferably 100 parts by weight or less, still more preferably 75 parts by weight, based on 100 parts by weight of the total of the bisphenol type epoxy compound and the polyfunctional epoxy compound. Parts 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 cure the resin composition. When the content of the thermosetting agent is not more than the above upper limit, it becomes difficult for the surplus thermosetting agent that was not involved in the curing to remain after curing, and the heat resistance of the cured product is further increased.

Spacer particles:
From the viewpoint of controlling the thickness of the cured product of the resin composition with higher accuracy, the resin composition preferably contains spacer particles. The resin composition containing the spacer particles can be used as a gap control material. When the resin composition containing the spacer is used for adhering the ferrite core, particularly the ferrite core in the inductor, the thickness of the cured product of the resin composition can be controlled with higher accuracy.

Examples of the spacer particles include resin particles, inorganic particles excluding metal particles, organic-inorganic hybrid particles, and metal particles. The spacer particles may be core-shell particles comprising a core and a shell disposed on the surface of the core. The core may be an organic core. The shell may be an inorganic shell. From the viewpoint of alleviating stress and vibration when stress is applied to the cured product or vibration is applied to the cured product and maintaining high adhesion, the spacer particles are preferably spacer particles other than metal particles. Inorganic particles excluding resin particles and metal particles or organic-inorganic hybrid particles are more preferable. Resin particles or organic-inorganic hybrid particles are particularly preferable as the spacer particles because the spacer particles are more excellent due to the effect of the present invention. When the resin composition containing the spacer particles is used for bonding the ferrite core, particularly the ferrite core in the inductor, and further used for applications such as in-vehicle use where stress or vibration is applied, the stress relaxation performance of the spacer particles is effective. The spacer particles can further effectively relieve stress and vibration.

The spacer particles are preferably resin particles formed of a resin. When the spacer particles are resin particles, when stress or vibration is applied to the cured product, the stress or vibration can be relaxed and high adhesion can be maintained.

Various organic substances are preferably used as the resin for forming the resin particles. Examples of the resin for forming the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene and polybutadiene; acrylic resins such as polymethylmethacrylate and polymethylacrylate; poly. Alkylene 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, polysulfone, polyphenylene Polymers obtained by polymerizing one or more of various polymerizable monomers having an oxide, a polyacetal, a polyimide, a polyamideimide, a polyether ether ketone, a polyether sulfone, and an ethylenically unsaturated group can be used. Can be mentioned. Since the hardness of the spacer particles can be easily controlled within a suitable range, the resin for forming the resin particles is a weight obtained by polymerizing one or more polymerizable monomers having a plurality of ethylenically unsaturated groups. It is preferably coalesced.

When the resin particles are obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, the polymerizable monomer having an ethylenically unsaturated group has a crosslinkability with a non-crosslinkable monomer. Can be mentioned as a monomer of.

Examples of the non-crosslinkable monomer include styrene-based monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride; and methyl ( Meta) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) Alkyl (meth) acrylate compounds such as meta) acrylate and isobornyl (meth) acrylate; oxygen atoms such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate and glycidyl (meth) acrylate. Containing (meth) acrylate compound; nitrile-containing monomer such as (meth) acrylonitrile; vinyl ether compound such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether; acid vinyl ester such as vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate, etc. Compounds; unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; halogen-containing monomers such as trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride, and chlorstyrene. Can be mentioned.

Examples of the crosslinkable monomer include tetramethylolmethanetetra (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolmethanedi (meth) acrylate, trimethylolpropanetri (meth) acrylate, and dipenta. Elythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) Polyfunctional (meth) acrylate compounds such as acrylates, (poly) tetramethylene glycol di (meth) acrylates, 1,4-butanediol di (meth) acrylates; triallyl (iso) cyanurate, triallyltrimethylate, divinylbenzene, Examples thereof include silane-containing monomers such as diallyl phthalate, diallyl acrylamide, diallyl ether, γ- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, and vinyltrimethoxysilane.

The resin particles can be obtained by polymerizing the polymerizable monomer having an ethylenically unsaturated group by a known method. Examples of this method include a method of suspension polymerization in the presence of a radical polymerization initiator, a method of swelling a monomer together with a radical polymerization initiator using non-crosslinked seed particles, and the like.

When the spacer particles are inorganic particles other than metal particles or organic-inorganic hybrid particles, examples of the inorganic substance for forming the spacer particles include silica and carbon black. It is preferable that the inorganic substance is not a metal. The particles formed of the silica are not particularly limited, but for example, after hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles, firing is performed as necessary. Examples include particles obtained by doing so. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

From the viewpoint of further improving the adhesion, the average particle size of the spacer particles is preferably 20 μm or more, more preferably 25 μm or more, still more preferably 30 μm or more, preferably 200 μm or less, and more preferably 150 μm or less. It is more preferably 130 μm or less.

From the viewpoint of further enhancing the adhesion, the CV value of the particle size of the spacer particles is preferably 1% or more, preferably 10% or less, and more preferably 5% or less.

From the viewpoint of further enhancing the adhesion, the compressive elastic modulus (10% K value) when the spacer particles are compressed by 10% is preferably 980 N / mm ² or more, more preferably 1200 N / mm ² or more. It is preferably 4900 N / mm ² or less, more preferably 3000 N / mm ² or less.

The CV value (coefficient of variation) is expressed by the following formula.

CV value (%) = (ρ / Dn) × 100
ρ: Standard deviation of particle size of spacer particles Dn: Mean value of particle size of spacer particles

The 10% K value of the spacer particles can be measured as follows.

Using a microcompression tester, spacer particles are compressed on a smooth indenter end face of a cylinder (diameter 50 μm, made of diamond) under the condition that a maximum test load of 90 mN is applied over 30 seconds at 25 ° C. At this time, the load value (N) and the compressive displacement (mm) are measured. From the obtained measured values, the compressive elastic modulus can be obtained by the following formula. As the microcompression tester, for example, "Fisherscope H-100" manufactured by Fisher Co., Ltd. is used.

K value (N / mm ² ) = (3/2 ^1/2 ) ・ F ・ S ^-3/2・ R- ^{1 / 2}
F: Load value (N) when the spacer particles are compressed and deformed by 10%
S: Compressive displacement (mm) when the spacer particles are compressed and deformed by 10%
R: Radius of spacer particles (mm)

From the viewpoint of further enhancing the moisture resistance and adhesion and further enhancing the uniformity of the thickness of the cured product, the content of the spacer particles in 100% by weight of the resin composition is preferably 1% by weight or more. It is more preferably 2% by weight or more, further preferably more than 5% by weight, preferably 15% by weight or less, and more preferably 12% by weight or less.

Inorganic filler:
From the viewpoint of further improving the moisture resistance, the resin composition preferably contains an inorganic filler. Examples of the material of the inorganic filler include silica, talc, clay, mica, hydrotalcite, alumina, magnesium oxide, aluminum hydroxide, aluminum nitride, and boron nitride.

From the viewpoint of further enhancing the moisture resistance, the inorganic filler is preferably silica or alumina, more preferably silica, and even more preferably molten silica. By using silica, the coefficient of thermal expansion of the cured product is further reduced, and the adhesive reliability is further increased.

From the viewpoint of further enhancing the moisture resistance, the inorganic filler is preferably a surface-treated product with a coupling agent.

Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, an aluminum coupling agent, and the like. From the viewpoint of further enhancing the adhesion, the inorganic filler is preferably a surface-treated product with a silane coupling agent.

Examples of the silane coupling agent include phenylsilane, vinylsilane, aminosilane, imidazolesilane, and epoxysilane. Phenylsilane is preferable from the viewpoint of further enhancing moisture resistance.

From the viewpoint of further enhancing the moisture resistance, the content of the inorganic filler in 100% by weight of the resin composition is preferably 10% by weight or more, more preferably more than 30% by weight, still more preferably more than 35% by weight. Particularly preferably, it is 40% by weight or more. From the viewpoint of further enhancing the adhesion, the content of the inorganic filler is preferably 90% by weight or less, more preferably 75% by weight or less, still more preferably 70% by weight or less, and particularly preferably 65% by weight or less, most preferably. Is 60% by weight or less.

From the viewpoint of improving both adhesion and moisture resistance in a well-balanced manner, the ratio of the content of the spacer particles to the content of the inorganic filler in the resin composition (spacer particle content / inorganic filler content). Is preferably 1/60 or more, more preferably 1/30 or more, 1/3 or less, and more preferably 1/4 or less on a weight basis.

From the viewpoint of further enhancing the adhesion, the ratio of the average particle size of the inorganic filler to the average particle size of the spacer particles (average particle size of the inorganic filler / average particle size of the spacer particles) is preferably 0.1 or less. , More preferably 0.01 or less. From the viewpoint of further enhancing the moisture resistance, the above ratio (average particle size of the inorganic filler / average particle size of the spacer particles) is preferably 0.00005 or more, more preferably 0.0005 or more.

The average particle size indicates a number average particle size. The average particle size of the inorganic filler and the spacer particles can be obtained, for example, by observing 50 arbitrary inorganic fillers or 50 arbitrary spacer particles with an electron microscope or an optical microscope and calculating an average value.

solvent:
The resin composition may or may not contain a solvent. The solvent is generally removed by volatilization when the resin composition is cured. Only one kind of the solvent may be used, or two or more kinds may be used in combination.

The solvent is generally an organic solvent. Examples of the organic solvent include ketone compounds such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbon compounds such as toluene, xylene and tetramethylbenzene, cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol and propylene glycol monomethyl. Glycol ether compounds such as ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, tripropylene glycol monomethyl ether, ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene. Ester compounds such as glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate and propylene carbonate, aliphatic hydrocarbon compounds such as octane and decane, petroleum solvents such as petroleum ether and naphtha, and dibasic acid esters. And so on. The dibasic acid ester is a solvent called DBE.

From the viewpoint of suppressing excessive wetting and spreading of the resin composition after coating, it is preferable that the content of the solvent in the resin composition is small. That is, when the resin composition is cured at 190 ° C. for 30 minutes to obtain a cured product, the weight reduction of the cured product with respect to the resin composition before curing is preferably 5% by weight or less, more preferably 3% by weight. % Or less. The weight loss at the time of curing corresponds to 100% by weight of the cured resin composition before curing, and is equivalent to the weight reduced by the cured product obtained by curing the resin composition. The amount of volatile components affects the weight reduction before and after curing. In the present invention, since the above-mentioned compounding composition is adopted, the viscosity of the resin composition can be sufficiently lowered even if a solvent is not used or the content of the solvent is reduced.

Other ingredients:
The resin composition may contain a photocurable component, or may contain a photocurable compound and a photopolymerization initiator.

From the viewpoint of further enhancing the adhesion, the resin composition preferably contains a coupling agent.

Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, an aluminum coupling agent, and the like. From the viewpoint of further enhancing the adhesion, the resin composition preferably contains a silane coupling agent.

Examples of the silane coupling agent include phenylsilane, vinylsilane, aminosilane, imidazolesilane, and epoxysilane.

From the viewpoint of further enhancing the adhesion, the content of the coupling agent in 100% by weight of the resin composition is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and preferably 0.1% by weight or more. It is 2% by weight or less, more preferably 1% by weight or less.

From the viewpoint of effectively enhancing the coatability, further enhancing the uniformity of the thickness of the cured product, further enhancing the adhesion, and further suppressing the generation of voids, the above resin composition contains a thixotropy-imparting agent. Is preferable.

Examples of the thixotropy-imparting agent include metal particles, calcium carbonate, fumed silica, aluminum oxide, boron nitride, aluminum nitride, and inorganic particles such as aluminum borate.

From the viewpoint of effectively improving the coatability, further improving the uniformity of the thickness of the cured product, further improving the adhesion, and further suppressing the generation of voids, the thixotropy in 100% by weight of the resin composition. The content of the imparting agent is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, preferably 10% by weight or less, and more preferably 5% by weight or less.

The resin composition may be used, for example, as a filler, a bulking agent, a softening agent, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, and the like. It may contain various additives such as lubricants, antistatic agents and flame retardant agents.

(Use of resin composition)
The resin composition can be used for various purposes. The resin composition is preferably an adhesive or a coating material, and more preferably an adhesive. The resin composition is preferably an adhesive for electronic parts or a coating material for electronic parts, and more preferably an adhesive for electronic parts. Since the resin composition can increase the adhesive strength and the adhesiveness, it can be suitably used as an adhesive for electronic parts.

Since the effect of the present invention is particularly effectively exhibited, the above resin composition is suitably used for bonding a ferrite core, and is preferably used for bonding a ferrite core in an inductor. When bonding a ferrite core in an inductor, a core material such as a ferrite core needs to be arranged with a gap. The resin composition is excellent in gap controllability, heat resistance and coatability, and excellent performance can be expected for adhesion of a ferrite core in an inductor. The resin composition is preferably an adhesive resin composition for an inductor, and preferably an adhesive for an inductor.

(Electronic parts)
The resin composition is preferably an adhesive for electronic components. Examples of electronic components include inductors and sensor chips.

The inductor preferably includes a ferrite core and an adhesive portion to which the ferrite core is adhered. In the above inductor, the material of the upper adhesive portion is preferably the above-mentioned resin composition. The adhesive portion is preferably a cured product of the resin composition. The adhesive portion is preferably formed by curing the resin composition.

It is preferable that the ferrite core is arranged on the surfaces of the adhesive portions on both sides facing each other. It is preferable that the ferrite core has a gap due to the adhesive portion.

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

The inductor 1 shown in FIG. 1 includes a ferrite core 11, a ferrite core 12, and an adhesive portion 13. The inductor 1 includes a plurality of ferrite cores (ferrite core 11 and ferrite core 12). The inductor 1 includes a coil iron core for transformer parts. The ferrite core 11 is an E-type ferrite core. The ferrite core 12 is an I-type farite core. Of the three convex portions of the E-type ferrite core 11, the tips of the two outer convex portions and the side surfaces of the I-type ferrite core 12 face each other and separate a gap. The adhesive portion 13 is arranged in this gap. The material of the adhesive portion 13 is the resin composition described above. In the present embodiment, the thickness of the adhesive portion 13 is equivalent to the particle size of the spacer particles contained in the adhesive portion 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 reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

The following materials were prepared.

(Bisphenol type epoxy compound)
Bisphenol type epoxy compound 1: Bisphenol E type epoxy resin, "R1710" manufactured by Printec Co., Ltd.
Bisphenol type epoxy compound 2: Bisphenol F type epoxy resin, "EXA830CRP" manufactured by DIC ("830CRP" in the table)
Bisphenol type epoxy compound 3: Bisphenol A type epoxy resin, "jer825" manufactured by Mitsubishi Chemical Corporation

(Epoxy compound different from bisphenol type epoxy compound)
Polyfunctional epoxy compound 1: Naphthalene type epoxy compound, "HP4710" manufactured by DIC Corporation
Polyfunctional epoxy compound 2: Fluorene type epoxy compound, "ogsol PG100" manufactured by Osaka Gas Chemical Co., Ltd. ("PG100" in the table)
Polyfunctional epoxy compound 3: Glycol uryl type epoxy compound, "TG-G" manufactured by Shikoku Kasei Kogyo Co., Ltd.
Polyfunctional epoxy compound 4: Dicyclopentadiene type epoxy compound, "HP7200" manufactured by DIC Corporation
Polyfunctional Epoxy Compound 5: Phenolic Novolac Epoxy Compound, "DEN431" manufactured by DOWN
Polyfunctional epoxy compound 6: resorcinol type epoxy compound, "TDG-LC" manufactured by Kyoeisha Chemical Co., Ltd.

(Thermosetting agent)
Thermosetting agent 1: Imidazole curing accelerator, "2MZA" manufactured by Shikoku Chemicals Corporation
Thermosetting agent 2: Acid anhydride type curing agent, "YH307" manufactured by Mitsubishi Chemical Corporation

(Inorganic filler)
Inorganic filler 1: Silica, average particle size 1 μm, “SE-4050SPE” manufactured by Admatex (“4050SPE” in the table)

(Spacer particles)
Spacer particles 1: Average particle diameter 20 μm, CV value 5%, 10% K value 3600 N / mm ² , Sekisui Chemical Co., Ltd. “SP-220”, Resin particles Spacer particles 2: Average particle diameter 25 μm, CV value 7%, Union "SPM-25", glass particles

(solvent)
Solvent 1: Methyl ethyl ketone

(Examples 1 to 11, 13 to 19, Reference Example 12 and Comparative Examples 1 to 7)
(1) Preparation of Resin Composition (Adhesive) According to the compositions of Tables 1 to 3, each material other than the spacer was stirred and mixed with a rotation / revolution mixer to obtain an adhesive composition. Spacer particles were blended into the obtained adhesive composition according to the compositions shown in Tables 1 to 3, and the mixture was stirred and mixed using a rotation / revolution mixer to prepare a resin composition (adhesive).

(2) Preparation of Inductor The obtained resin composition is filled in a 10 mL syringe (manufactured by Musashi Engineering Co., Ltd.), a precision nozzle (manufactured by Musashi Engineering Co., Ltd., nozzle tip inner diameter 0.3 mm) is attached to the tip of the syringe, and a dispenser device (manufactured by Musashi Engineering Co., Ltd.) is attached. Using "SHOT MASTER 300" manufactured by Musashi Engineering Co., Ltd.), it was applied to an I-type core and bonded to an E-type core. Then, it was cured in a reflow oven to obtain an inductor.

(evaluation)
(1) Viscosity The viscosity (η25) of the resin composition at 25 ° C. was measured at 25 ° C. and 5 rpm using an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.).

(2) Glass transition temperature The adhesive was heated at 190 ° C. for 30 minutes to obtain a cured product. The tan δ of the obtained cured product was measured using a dynamic viscoelasticity measuring machine (manufactured by IT Measurement Control Co., Ltd.) at a heating rate of 10 ° C./min, a grip width of 20 mm, and a frequency of 5 Hz. The temperature at which tan δ was maximized was defined as the glass transition temperature.

(3) 5% Weight Reduction Temperature The resin composition was heated at 190 ° C. for 30 minutes to obtain a cured product. The obtained cured product shall be measured using a differential thermogravimetric simultaneous measuring device (“TG-DTA6200” manufactured by Seiko Instruments) under the conditions of a temperature range of 30 ° C to 480 ° C and a heating rate of 10 ° C / min. The 5% weight loss temperature of the resin composition was evaluated. The 5% weight loss temperature was determined according to the following criteria.

[Criteria for determining 5% weight loss temperature]
◯: 5% weight loss temperature is 380 ° C or higher Δ: 5% weight loss temperature is 360 ° C or higher and less than 380 ° C ×: 5% weight loss temperature is less than 360 ° C

(4) High temperature adhesive strength (adhesiveness)
The obtained resin composition was applied to a test piece manufactured by SPCC-SB, and the test pieces were adhered to each other at 190 ° C. for 30 minutes. After bonding, the shear strength was measured at a speed of 1 mm / min and 150 ° C. using a universal testing machine (Tensilon UTA manufactured by Orientec) to evaluate the high-temperature bonding strength. From the adhesive strength, the high temperature adhesive force (adhesiveness) was determined according to the following criteria.

[Criteria for high temperature adhesive strength]
◯: High temperature adhesive force is 10 MPa or more Δ: High temperature adhesive force is 6 MPa or more and less than 10 MPa ×: High temperature adhesive force is less than 6 MPa

(5) Gap controllability In the obtained inductor, the variation 3σ (σ; standard deviation) of the gap-to-gap distance and the gap-to-gap distance after curing is measured using a laser displacement meter (“KS-1100” manufactured by KEYENCE). did. The gap controllability was evaluated from the variation of the gap distance 3σ / the value X of the gap distance after curing. The gap controllability was judged according to the following criteria.

[Gap controllability criteria]
○ ○: Value X is less than 0.15 ○: Value X is 0.15 or more and less than 0.2 Δ: Value X is 0.2 or more and less than 0.4 ×: Value X 0.4 or more

(6) Weight reduction during curing (amount of volatile components)
The resin composition was heated at 190 ° C. for 30 minutes to obtain a cured product. The amount of volatile components in the resin composition was evaluated by measuring the weight loss of the cured product with respect to the resin composition before curing. The weight loss during curing was determined according to the following criteria.

[Criteria for weight loss during curing]
◯: Weight loss is 2% by weight or less Δ: Weight loss is more than 2% and 5% or less ×: Weight loss is more than 5%

Details and results are shown in Tables 1 to 3 below.

1 ... Inductor 11 ... Ferrite core (E type)
12 ... Ferrite core (I type)
13 ... Adhesive part

Claims (10)

Used for bonding ferrite cores
Bisphenol type epoxy compound and
Polyfunctional epoxy compounds different from bisphenol type epoxy compounds,
Including thermosetting agent
The ratio of the content of the polyfunctional epoxy compound to the content of the bisphenol type epoxy compound is 3/7 or less on a weight basis.
The viscosity at 25 ° C. is 40 Pa · s or less,
A resin composition having a glass transition temperature of 170 ° C. or higher when the cured product is obtained by curing at 190 ° C. for 30 minutes. The resin composition according to claim 1, wherein the polyfunctional epoxy compound has a naphthalene skeleton, a fluorene skeleton, a glycoluril skeleton, a dicyclopentadiene skeleton, or a phenol novolac skeleton. The resin composition according to claim 1 or 2, wherein the bisphenol type epoxy compound is a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, or a bisphenol E type epoxy compound. The invention according to any one of claims 1 to 3, wherein the weight loss of the cured product with respect to the resin composition before curing is 5% by weight or less when the cured product is obtained by curing at 190 ° C. for 30 minutes. Resin composition. The one according to any one of claims 1 to 4, wherein the ratio of the content of the polyfunctional epoxy compound to the content of the bisphenol type epoxy compound is 1/9 or more and 3/7 or less on a weight basis. Resin composition. The resin according to any one of claims 1 to 5, wherein the 5% weight loss temperature by thermogravimetric analysis of the cured product is 360 ° C. or higher when the cured product is obtained by curing at 190 ° C. for 30 minutes. Composition. The resin composition according to any one of claims 1 to 6, which comprises spacer particles. The resin composition according to any one of claims 1 to 7, which is an adhesive for electronic parts. The resin composition according to any one of claims 1 to 8 , which is used for adhering a ferrite core in an inductor. Ferrite core and
It is provided with an adhesive portion for adhering the ferrite core.
An inductor in which the material of the adhesive portion is the resin composition according to any one of claims 1 to 9 .

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