JP7394782B2 - High voltage withstand heat dissipating insulating resin composition and electronic components using the same - Google Patents

Description

The present invention relates to a heat dissipating insulating resin composition with excellent withstand voltage, and electronic components using the same, and more specifically, to a high withstand voltage heat dissipating insulation having excellent withstand voltage characteristics without reducing thermal conductivity. The present invention relates to a synthetic resin composition and electronic components such as printed wiring boards using the same.

In recent years, there has been a need to reduce _CO2 emissions as a measure against global warming, and as a measure against automobile exhaust gas, the development of vehicles that use high-output motors, such as electric cars and hybrid cars, is underway. When power is supplied from a battery to a motor, power transistors and power diodes, which are used to convert high voltage and high current, generate heat during operation, which is a problem. It is expected that this problem of heat generation will become more pronounced in the next generation of electric vehicles that are planned. Therefore, further improvements in high thermal conductivity and high heat dissipation are required.

As a printed wiring board with good heat dissipation, for example, Patent Document 1 uses a metal plate made of copper or aluminum, and coats one or both sides of this metal plate with an electrical insulating layer such as prepreg or thermosetting resin composition. A metal-based substrate on which a circuit pattern is formed is disclosed.

Further, for example, Patent Document 2 describes a high heat conductive resin cured product containing a certain large particle size filler in a certain proportion, and Patent Document 3 describes a high heat conductive resin cured product containing a certain small particle size filler in a certain proportion. A conductive resin cured product is disclosed.

Japanese Patent Application Publication No. 6-224561 Japanese Patent Application Publication No. 2014-189701 Japanese Patent Application Publication No. 2014-193565

However, in the metal base substrate according to the invention described in Patent Document 1, since the electrical insulating layer has low thermal conductivity, it is necessary to make the insulating layer thin, and as a result, the withstand voltage characteristics of the electrical insulating layer decreases. There was such a problem.

Moreover, in the highly thermally conductive cured resin products according to the inventions described in Patent Documents 2 and 3, fine bubbles (microbubbles) generated in the voids of the filler also reduce the withstand voltage characteristics. Therefore, in order to close-pack the highly thermally conductive particles while preventing this, mechanical processing such as pressure molding or vacuum pressing is required, which is time-consuming and has a problem of poor workability.

The present invention has been made in view of the above problems, and its main purpose is to provide high thermal conductivity, good heat dissipation, prevent deterioration of withstand voltage characteristics, and allow mechanical processing such as pressure forming and vacuum pressing to be performed. An object of the present invention is to provide a heat dissipating insulating resin composition with an unnecessary high withstand voltage.

Another object of the present invention is to provide an electronic component having a cured product obtained by thermally and/or photocuring the above-mentioned high voltage withstand heat dissipating insulating resin composition.

The inventor conducted intensive research toward realizing the above object. As a result, together with (B) the curable resin, (A-1) high thermal conductive particles having a specific surface area of 0.2 to 0.6 m ² /g as measured by the BET method as (A) high thermal conductive particles, By blending (A-2) highly thermally conductive particles with a specific surface area of 6.0 to 12.5 m ² /g as measured by the BET method in a constant ratio, close-packing can be achieved. The present inventors have discovered that it is possible to achieve this, and to improve the withstand voltage characteristics without reducing thermal conductivity, and have completed the present invention.

That is, the high withstand voltage heat dissipating insulating resin composition of the present invention is a high withstanding voltage heat dissipating insulating resin composition containing (A) highly thermally conductive particles and (B) a curable resin, A) The volume occupancy of the highly thermally conductive particles is 60% by volume or more with respect to the total solid content of the high voltage withstand heat dissipating insulating resin composition, and the high thermally conductive particles (A) are (A-1 ) Highly thermally conductive particles with a specific surface area of 0.2 to 0.6 m ² /g measured by the BET method and (A-2) High heat particles with a specific surface area of 6.0 to 12.5 m ² /g measured by the BET method High thermal conductive particles containing conductive particles and having a specific surface area of 6.0 to 12.5 m ² /g as measured by the (A-2) BET method based on the total weight of the (A) high thermal conductive particles. is 5 to 16% by weight. Note that the solid content of the composition refers to the composition excluding the organic solvent.

The high voltage withstand heat dissipating insulating resin composition of the present invention preferably further contains (C) an organic solvent, and is preferably of a coating type.

In the high withstand voltage heat dissipating insulating resin composition of the present invention, the (A) high thermal conductive particles are preferably aluminum oxide particles.

In the high withstand voltage heat dissipating insulating resin composition of the present invention, the (A) high thermal conductive particles have (A-1) high thermal conductivity with a specific surface area of 0.2 to 0.6 m ² /g measured by the BET method. (A-2) High thermal conductive particles having a specific surface area of 6.0 to 12.5 m ² /g as measured by the BET method.

The high withstand voltage heat dissipating insulating resin composition of the present invention contains at least one of (B-1) a thermosetting resin or (B-2) a photocurable resin as the (B) curable resin. It is preferable to do so.

The high withstand voltage heat dissipating insulating resin composition of the present invention contains an epoxy compound and/or an oxetane compound as the thermosetting resin (B-1), and may further contain a curing agent and/or a curing catalyst. preferable.

The high withstand voltage heat dissipating insulating resin composition of the present invention contains a compound having one or more ethylenically unsaturated bonds in one molecule as the photocurable resin (B-2), and further initiates photopolymerization. It is preferable to contain an agent.

The cured product of the present invention is characterized in that it is obtained by curing the high voltage withstand heat dissipating insulating resin composition. The electronic component of the present invention is characterized by having the cured product. Preferably, in the electronic component of the present invention, an insulating layer and/or a solder resist layer is formed of a cured product obtained by thermally curing and/or photocuring the high withstand voltage heat dissipating insulating resin composition. .

According to the present invention, there is provided a high withstand voltage heat dissipating insulating resin composition that has high thermal conductivity, good heat dissipation properties, can prevent a decrease in voltage withstand characteristics, and does not require mechanical processing such as pressure molding or vacuum pressing. be able to. Furthermore, electronic components such as printed wiring boards in which an insulating layer and/or a solder resist layer are formed by a cured product obtained by thermosetting and/or photocuring the above-mentioned high withstand voltage heat dissipating insulating resin composition are also available. can be provided. Note that the composition of the present invention can also be provided for filling holes such as via holes and through holes in printed wiring boards.

The high withstand voltage heat dissipating insulating resin composition of the present invention is a high withstanding voltage heat dissipating insulating resin composition comprising (A) highly thermally conductive particles and (B) a curable resin, which comprises (A) The volume occupancy of the highly thermally conductive particles is 60% by volume or more based on the total solid volume of the high withstand voltage heat dissipating insulating resin composition, and the (A) high thermally conductive particles are (A-1) BET (A-2) High thermal conductive particles with a specific surface area of 6.0 to 12.5 ^{m 2 /} g measured by the BET method. 5 of the high thermal conductive particles having a specific surface area of 6.0 to 12.5 m ² /g as measured by the (A-2) BET method based on the total weight of the high thermal conductive particles (A). It is characterized by a content of 16% by weight. In addition, the "BET method" for measuring the specific surface area in the present invention includes a method in which, for example, a fully automatic BET specific surface area measuring device Massorb HM-1201 manufactured by Mountech Co., Ltd. is used and actual measurement is performed using the BET single point method measurement. Yes, but not limited to this.

The present invention provides (A) highly thermally conductive particles (A-1) particles with a specific surface area of 0.2 to 0.6 m ² /g measured by the BET method and (A-2) particles with a specific surface area measured by the BET method. In addition to using particles with a diameter of 6.0 to 12.5 m ² /g, the total amount of the particles is 60% by volume or more based on the total solid content of the high voltage heat dissipating insulating resin composition, thereby improving thermal conductivity. The material has a high thermal conductivity and has sufficient thermal conductivity as a heat dissipating material.

(A-1) It is possible to increase thermal conductivity by including highly thermally conductive particles with a specific surface area of 0.2 to 0.6 m ² /g measured by the BET method, but this alone cannot is low, making it unsuitable as an insulating material under high voltage. Therefore, in the present invention, (A-2) high thermal conductive particles with a specific surface area of 6.0 to 12.5 m ² /g measured by the BET method are added at a certain ratio ((A) to the total weight of the high thermal conductive particles, (5 to 16% by weight) improves the withstand voltage characteristics. (A-2) By blending a certain ratio of highly thermally conductive particles with a specific surface area of 6.0 to 12.5 m ² /g as measured by the BET method, and preferably containing (C) an organic solvent, the present invention The high voltage withstand heat dissipating insulating resin composition can now be suitably used as a paint, and by applying it thinly as a paint, fine bubbles adhering to the voids of the filler can be removed. Therefore, in the high withstand voltage heat dissipating insulating resin composition of the present invention, it is possible to achieve high withstand voltage and (A) high heat without performing mechanical processing such as pressure molding or vacuum pressing, which is laborious and has poor workability. By close-packing conductive particles, it is possible to achieve both high thermal conductivity, that is, high heat dissipation.

In addition, if high thermal conductive particles with a specific surface area of 1.0 to 1.8 m ² /g measured by the BET method are between (A-1) and (A-2) are further included, the withstand voltage will not improve. , In addition, high thermal conductivity particles with a specific surface area of 55 m ² /g or more, which is larger than (A-2) measured by the BET method, have high thixotropy and it becomes difficult to reduce the voids in the filler, so the thermal conductivity Both withstand voltage characteristics decrease. Therefore, in the present invention, (A) highly thermally conductive particles are (A-1) particles with a specific surface area of 0.2 to 0.6 m ² /g measured by the BET method, and (A-2) particles with a specific surface area measured by the BET method. It is preferable that the specific surface area measured by the BET method is 6.0 to 12.5 m ² /g, while (A-2) the specific surface area measured by the BET method is 6.0 to 12.5 m 2 /g. When only highly thermally conductive particles with an area of 12.5 m ² /g are used, the withstand voltage characteristics are greatly reduced compared to the present invention. In addition, (A-1) particles with a specific surface area of 0.2 to 0.6 m ² /g measured by the BET method and (A-2) particles with a specific surface area of 6.0 to 12.5 m ² /g measured by the BET method. If particles g are not used at all, the thermal conductivity becomes extremely low and the composition does not have the properties as a heat dissipating insulating resin composition.

Hereinafter, each component of the high voltage withstand heat dissipating insulating resin composition of the present invention will be explained in detail.

The (A) high thermal conductive particles of the present invention have a volume occupancy of 60% by volume or more based on the total solid content of the high voltage withstand heat dissipating insulating resin composition, and the (A) high thermal conductive particles However, (A-1) highly thermally conductive particles with a specific surface area of 0.2 to 0.6 m ² /g as measured by the BET method and (A-2) particles with a specific surface area of 6.0 to 12.0 m 2 /g as measured by the BET method. Contains 5 m ² /g of high thermal conductive particles, and has a specific surface area of 6.0 to 12.5 m ² /g as measured by the (A-2) BET method based on the total weight of the (A) high thermal conductive particles. It is characterized in that the amount of highly thermally conductive particles in g is 5 to 16% by weight.

In the present invention, as the material for the high thermal conductivity particles (A), any known and commonly used material can be used as long as it has high thermal conductivity. For example, aluminum oxide (Al ₂ O ₃ ), silica (SiO ₂ ), silicon carbide (SiC), zirconia (ZrO ₂ ), titanium oxide (TiO ₂ ), magnesium oxide (MgO), mullite ( _{3Al 2} O 3.2SiO ₂ ), zircon (particularly ZrO ₂ .SiO ₂ ), cordierite (2MgO .2Al ₂ O ₃ .5SiO ₂ ), silicon nitride (Si ₃ N ₄ ), manganese oxide (MnO ₂ ), iron oxide ( Fe ₂ O ₃ ), cobalt oxide (CoO), and the like can be used.

Among these, aluminum oxide is preferable because it is chemically stable and has excellent insulation properties, and spherical particles are suitable for close-packing because they can moderate the increase in viscosity when highly packed. Preferably, aluminum is used. Commercially available spherical aluminum oxide particles include (A-1) DAW-03 (Denki Kagaku Kogyo Co., Ltd.) as highly thermally conductive particles with a specific surface area of 0.2 to 0.6 m ² /g measured by the BET method; DAW-05 (manufactured by Denki Kagaku Kogyo Co., Ltd., specific surface area 0.5 to 0.6 m ² /g measured by BET method), DAW-05 (manufactured by Denki Kagaku Kogyo Co., Ltd., specific surface area 0.4 to 0.5 m ² /g measured by BET method) ), DAW-07 (manufactured by Denki Kagaku Kogyo Co., Ltd., specific surface area 0.4 m ² /g measured by BET method), DAW-45 (manufactured by Denki Kagaku Kogyo Co., Ltd., specific surface area 0.4 m 2 /g measured by BET method). (A-2) Specific surface ^area measured by ^BET method is 6.0. As highly thermally conductive particles of ~12.5 m ² /g, AO-502 (manufactured by Admatec, specific surface area 6.5 to 9.0 m ² /g measured by BET method), ASFP-20 (Denki Kagaku Kogyo Co., Ltd.) ), ASFP-25 (manufactured by Denki Kagaku Kogyo Co., Ltd., specific surface area 8 to 10 ^{m 2} /g measured by the BET method), ASFP-40 (denki Specific surface area: 6 to 8 m ² /g (manufactured by Kagaku Kogyo Co., Ltd., measured by BET method), etc.

In addition, (A) high thermal conductivity particles of the present invention include (A-1) particles with a specific surface area of 0.2 to 0.6 m ² /g measured by the BET method and (A-2) particles with a specific surface area measured by the BET method. High filling can be achieved by satisfying the condition of particles having a specific surface area of 6.0 to 12.5 m ² /g.

Note that it is preferable to surface-treat the highly thermally conductive particles (A) of the present invention with a coupling agent such as a silane coupling agent in order to improve the low water absorption, thermal shock resistance, and crack resistance of the cured product. As this coupling agent, silane-based, titanate-based, aluminate-based, zircoaluminate-based coupling agents, and the like can be used. Among these, silane coupling agents are preferred. Examples of such silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, N-(2-aminomethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-amino Propyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-anilinopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxy Examples include cyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane, and these can be used alone or in combination.
These coupling agents may be prepared by separately blending the surface-untreated (A) highly thermally conductive particles and the coupling agent, and in which the (A) highly thermally conductive particles are surface-treated in the composition. It is preferable to immobilize the coupling agent on the surface of the highly thermally conductive particles (A) in advance by adsorption or reaction. In this case, the amount of coupling agent used for surface treatment and the surface treatment method are not particularly limited.

In the present invention, it is preferable that the curable resin (B) contains at least either (B-1) a thermosetting resin or (B-2) a photocurable resin.

(B-1) Examples of thermosetting resins include resins that harden by heating and exhibit electrical insulation properties, such as epoxy resins, oxetane resins, melamine resins, and silicone resins. In particular, in the present invention, epoxy compounds Thermosetting resins of and/or oxetane compounds can be preferably used, and in this case, it is preferable to further use a curing agent and/or a curing catalyst.

As the above-mentioned epoxy compound, any known and commonly used epoxy compound can be used as long as it has one or more, preferably two or more, epoxy groups in one molecule. For example, bisphenol A type epoxy resin, bisphenol S type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, alicyclic epoxy resin, trimethylolpropane polyglycidyl ether, phenyl-1,3 - diglycidyl ether, biphenyl-4,4'-diglycidyl ether, 1,6-hexanediol diglycidyl ether, diglycidyl ether of ethylene glycol or propylene glycol, sorbitol polyglycidyl ether, tris(2,3-epoxypropyl) Examples include compounds having two or more epoxy groups in one molecule, such as isocyanurate and triglycidyl tris(2-hydroxyethyl) isocyanurate. Furthermore, monoepoxy compounds such as butyl glycidyl ether, phenyl glycidyl ether, glycidyl (meth)acrylate, etc. may be added within a range that does not deteriorate the properties of the cured coating film. Further, these can be used alone or in combination of two or more types depending on the demand for improving the properties of the coating film.

（式中、Ｒ^１は、水素原子又は炭素数１～６のアルキル基を示す。）
オキセタン環を含有する化合物であり、具体的な化合物としては、３－エチル－３－ヒドロキシメチルオキセタン（東亞合成（株）製の商品名 ＯＸＴ－１０１）、３－エチル－３－（フェノキシメチル）オキセタン（東亞合成（株）製の商品名 ＯＸＴ－２１１）、３－エチル－３－（２－エチルヘキシロキシメチル）オキセタン（東亞合成社製の商品名 ＯＸＴ－２１２）、１，４－ビス｛［（３－エチル－３－オキセタニル）メトキシ］メチル｝ベンゼン（東亞合成社製の商品名 ＯＸＴ－１２１）、ビス（３－エチル－３－オキセタニルメチル）エーテル（東亞合成社製の商品名 ＯＸＴ－２２１）などが挙げられる。さらに、フェノールノボラックタイプのオキセタン化合物なども挙げられる。Further, the oxetane compound is represented by the following general formula (I),

(In the formula, R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)
It is a compound containing an oxetane ring, and specific examples include 3-ethyl-3-hydroxymethyloxetane (trade name OXT-101, manufactured by Toagosei Co., Ltd.), 3-ethyl-3-(phenoxymethyl) Oxetane (trade name OXT-211, manufactured by Toagosei Co., Ltd.), 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane (trade name OXT-212, manufactured by Toagosei Co., Ltd.), 1,4-bis{ [(3-ethyl-3-oxetanyl)methoxy]methyl}benzene (trade name OXT-121 manufactured by Toagosei Co., Ltd.), bis(3-ethyl-3-oxetanylmethyl)ether (trade name OXT- manufactured by Toagosei Co., Ltd.) 221), etc. Further examples include phenol novolac type oxetane compounds.

The above-mentioned oxetane compound can be used in combination with the above-mentioned epoxy compound or alone, but since the reactivity is lower than that of the epoxy compound, care must be taken such as increasing the curing temperature.

Examples of curing agents used include polyfunctional phenol compounds, polycarboxylic acids and their acid anhydrides, aliphatic or aromatic primary or secondary amines, polyamide resins, and polymercapto compounds. Among these, polyfunctional phenol compounds, polycarboxylic acids and acid anhydrides thereof are preferably used from the viewpoint of workability and insulation properties.

As the polyfunctional phenol compound, any known and commonly used compound can be used as long as it is a compound having two or more phenolic hydroxyl groups in one molecule. Specifically, phenol novolac resins, cresol novolac resins, bisphenol A, allylated bisphenol A, bisphenol F, bisphenol A novolac resins, vinylphenol copolymer resins, etc. are mentioned, but in particular, phenol novolac resins are highly reactive. It is preferable because it has a high heat resistance and a high effect of increasing heat resistance. Such a polyfunctional phenol compound also undergoes an addition reaction with the epoxy compound and/or oxetane compound in the presence of an appropriate curing catalyst.

Polycarboxylic acids and their acid anhydrides are compounds having two or more carboxyl groups in one molecule and their acid anhydrides, such as (meth)acrylic acid copolymers, maleic anhydride copolymers, Examples include condensates of dibasic acids. Commercially available products include Joncryl (product group name) manufactured by Johnson Polymer Co., Ltd., SMA resin (product group name) manufactured by Arco Chemical Co., Ltd., and polyazelaic acid anhydride manufactured by Shinnihon Chemical Co., Ltd.

The curing catalyst is a compound that serves as a curing catalyst for the reaction of an epoxy compound and/or oxetane compound with a polyfunctional phenol compound and/or polycarboxylic acid and its acid anhydride, or a polymerization catalyst when no curing agent is used. Compounds such as tertiary amines, tertiary amine salts, quaternary onium salts, tertiary phosphines, crown ether complexes, and phosphonium ylides can be arbitrarily selected from these. These can be used alone or in combination of two or more.

Among these, preferred are imidazoles such as trade names 2E4MZ, C11Z, C17Z, and 2PZ, imidazole AZINE compounds such as trade names 2MZ-A and 2E4MZ-A, and trade names 2MZ-OK and 2PZ-OK. Isocyanurates of imidazole such as, imidazole hydroxymethyl derivatives such as trade names 2PHZ and 2P4MHZ (all the above trade names are manufactured by Shikoku Kasei Kogyo Co., Ltd.), dicyandiamide and its derivatives, melamine and its derivatives, diaminomaleonitrile and its derivatives. derivatives, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, bis(hexamethylene)triamine, triethanolaminediaminodiphenylmethane, amines such as organic acid dihydrazide, 1,8-diazabicyclo[5,4,0]undecene-7 ( 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5,5]undecane (product name ATU, manufactured by Ajinomoto Co., Inc.) ), or organic phosphine compounds such as triphenylphosphine, tricyclohexylphosphine, tributylphosphine, and methyldiphenylphosphine.

The amount of these curing catalysts to be blended is sufficient in a usual quantitative ratio, for example, 0.1 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the epoxy compound and/or oxetane compound in total.

(B-2) The photocurable resin may be any electrically insulating resin that is cured by active energy ray irradiation, but compounds having one or more ethylenically unsaturated bonds in one molecule are heat resistant, It has excellent electrical insulation properties and can be preferably used. In this case, it is preferable to further use a photopolymerization initiator.
As the compound having one or more ethylenically unsaturated bonds in one molecule, known and commonly used photopolymerizable oligomers, photopolymerizable vinyl monomers, and the like are used.

Examples of the photopolymerizable oligomer include unsaturated polyester oligomers, (meth)acrylate oligomers, and the like. Examples of (meth)acrylate oligomers include epoxy (meth)acrylates such as phenol novolak epoxy (meth)acrylate, cresol novolac epoxy (meth)acrylate, and bisphenol type epoxy (meth)acrylate, urethane (meth)acrylate, and epoxyurethane (meth)acrylate. ) acrylate, polyester (meth)acrylate, polyether (meth)acrylate, polybutadiene-modified (meth)acrylate, and the like. Note that in this specification, (meth)acrylate is a term that collectively refers to acrylate, methacrylate, and mixtures thereof, and the same applies to other similar expressions.

The photopolymerizable vinyl monomers include known and commonly used ones, such as styrene derivatives such as styrene, chlorostyrene, and α-methylstyrene; vinyl esters such as vinyl acetate, vinyl butyrate, and vinyl benzoate; vinyl isobutyl ether, vinyl - Vinyl ethers such as n-butyl ether, vinyl-t-butyl ether, vinyl-n-amyl ether, vinyl isoamyl ether, vinyl-n-octadecyl ether, vinyl cyclohexyl ether, ethylene glycol monobutyl vinyl ether, triethylene glycol monomethyl vinyl ether; acrylamide , (meth)acrylamides such as methacrylamide, N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, N-methoxymethylacrylamide, N-ethoxymethylacrylamide, and N-butoxymethylacrylamide; triallylisocyanurate, diallyl phthalate , allyl compounds such as diallyl isophthalate; 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate Esters of (meth)acrylic acid such as; hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate; methoxyethyl (meth)acrylate, ethoxy Alkoxyalkylene glycol mono(meth)acrylates such as ethyl(meth)acrylate; ethylene glycol di(meth)acrylate, butanediol di(meth)acrylates, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate (meth)acrylate, alkylene polyol poly(meth)acrylate such as trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate; diethylene glycol di(meth)acrylate, triethylene Polyoxyalkylene glycol poly(meth)acrylates such as glycol di(meth)acrylate, polyethylene glycol 200 di(meth)acrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane tri(meth)acrylate; Hydroxyvivalin Examples include poly(meth)acrylates such as acid neopentyl glycol ester di(meth)acrylate; isocyanurate type poly(meth)acrylates such as tris[(meth)acryloxyethyl]isocyanurate. These can be used alone or in combination of two or more, depending on the requirements for the properties of the coating film.

Examples of the photopolymerization initiator include benzoin compounds and their alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and benzyl methyl ketal. ; Acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, diethoxyacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1- Acetophenones such as dichloroacetophenone, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one; methylanthoraquinone, 2-ethylanthoraquinone , 2-tert-butyl anthoraquinone, 1-chloroanthraquinone, 2-amyl anthoraquinone and other anthoraquinones; thioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-dichlorothioxanthone, 2 - Thioxanthone such as methylthioxanthone and 2,4-diisopropylthioxanthone; Ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; Benzophenones such as benzophenone and 4,4-bismethylaminobenzophenone. It will be done. These can be used alone or in combination of two or more, and further include tertiary amines such as triethanolamine and methyldiethanolamine; 2-dimethylaminoethylbenzoic acid, ethyl 4-dimethylaminobenzoate, etc. It can be used in combination with photoinitiation aids such as benzoic acid derivatives.

(B) When an alkali-developable photocurable resin composition is used as the curable resin, a carboxyl group is added to the ethylenically unsaturated bond-containing compound as a component of the photocurable resin (B-2). A carboxyl group-containing resin not having an ethylenically unsaturated bond can be used in addition to the above-mentioned compound having an ethylenically unsaturated bond.

The high voltage withstand heat dissipating insulating resin composition of the present invention is preferably of a coating type containing (C) an organic solvent. (C) Organic solvents are also used for composition adjustment and viscosity adjustment. (C) As the organic solvent, any known organic solvent can be used, such as ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; Glycol ethers such as , methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, tripropylene glycol monomethyl ether; ethyl acetate, butyl acetate , esters such as butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, propylene carbonate; aliphatic hydrocarbons such as octane and decane; Organic solvents such as petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha can be used. These organic solvents can be used alone or in combination of two or more.

The blending amount of the organic solvent (C) is preferably 3 to 10 parts by weight based on 100 parts by weight of the highly thermally conductive particles (A). (C) When the blending amount of the organic solvent is within this range, the generation of voids can be effectively suppressed during drying of the solvent.

If necessary, a wetting/dispersing agent may be added to the high voltage heat dissipating insulating resin composition of the present invention in order to facilitate high filling. Examples of such wetting/dispersing agents include compounds with polar groups such as carboxyl groups, hydroxyl groups, and acid esters, and polymeric compounds, such as acid-containing compounds such as phosphoric acid esters, copolymers containing acid groups, and hydroxyl groups. Containing polycarboxylic acid esters, polysiloxanes, salts of long-chain polyaminoamides and acid esters, etc. can be used.

Commercially available wetting/dispersing agents that can be particularly preferably used include Disperbyk (registered trademark) -101, -103, -110, -111, -160, -171, -174, -190, - 300, Bykumen (registered trademark), BYK-P105, -P104, -P104S, -240 (all manufactured by BYK Chemie Japan), EFKA-Polymer 150, EFKA-44, -63, -64, -65, Examples include -66, -71, -764, -766, and N (all manufactured by Efka).

The high withstand voltage heat dissipating insulating resin composition of the present invention may further contain known and commonly used materials such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black, naphthalene black, etc. colorants, known and commonly used thermal polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, pyrogallol, and phenothiazine, known and commonly used thickeners such as finely divided silica, organic bentonite, and montmorillonite, silica, barium sulfate, and talc. Known and commonly used extender pigments such as clay, hydrotalcite, antifoaming agents and/or leveling agents such as silicone-based, fluorine-based, and polymer-based agents can be blended. In the high voltage withstand heat dissipating insulating resin composition of the present invention, it is preferable to use a silicone antifoaming agent and a non-silicon antifoaming agent in combination, since bubbles (microbubbles) are more likely to come out when applied.

It is preferable that the high withstand voltage heat dissipating insulating resin composition of the present invention is adjusted to a viscosity suitable for the coating method using (C) an organic solvent, and then coated onto a substrate by a method such as screen printing.

When containing (B-1) thermosetting resin as the (B) curable resin of the high voltage withstanding heat dissipating insulating resin composition, after application, heat curing to a temperature of approximately 140°C to 180°C. A cured coating film can be obtained.

In addition, when the high voltage insulating curable resin composition contains (B-2) a photocurable resin as the curable resin (B), after application, it may be irradiated with ultraviolet rays using a high-pressure mercury lamp, metal halide lamp, xenon lamp, etc. A cured coating film can be obtained.

In addition, as (B) curable resin of the high withstand voltage insulating curable resin composition, an alkali-developable photocurable resin that is a mixture of (B-1) thermosetting resin and (B-2) photocurable resin is used. If the composition contains a synthetic resin composition, after coating, it is pattern-exposed to ultraviolet rays from a high-pressure mercury lamp, metal halide lamp, xenon lamp, etc., developed, and heated to a temperature of approximately 140°C to 180°C for thermosetting. A patterned cured coating can be obtained.

The present invention will be specifically explained by showing examples and comparative examples of the present invention, but it goes without saying that the present invention is not limited to the following examples. In the following, "parts" and "%" refer to "parts by mass" and "% by mass" unless otherwise specified.

(Synthesis of photopolymerizable oligomer (B-2))
In a 2-liter separable flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and a nitrogen introduction tube, 900 g of diethylene glycol dimethyl ether and t-butyl peroxy 2-ethylhexanoate (Perbutyl, manufactured by NOF Corporation) were placed. After charging 21.4 g of O) and raising the temperature to 90°C, 309.9 g of methacrylic acid, 116.4 g of methyl methacrylate, and lactone-modified 2-hydroxyethyl methacrylate represented by general formula (I) (Daicel Chemical Industries, Ltd. ) was added dropwise to diethylene glycol dimethyl ether over 3 hours together with 21.4 g of bis(4-t-butylcyclohexyl)peroxydicarbonate (Perloyl TCP, manufactured by NOF Corporation), and then for a further 6 hours. A carboxyl group-containing copolymer resin solution was obtained by aging. The reaction was conducted under a nitrogen atmosphere.
Next, 363.9 g of 3,4-epoxycyclohexylmethyl acrylate (Cyclomer A200 manufactured by Daicel Chemical Co., Ltd.), 3.6 g of dimethylbenzylamine, and 1.80 g of hydroquinone monomethyl ether were added to the above carboxyl group-containing copolymer resin solution. The ring-opening addition reaction of epoxy was carried out by raising the temperature to 100° C. and stirring. After 16 hours, a solution containing 53.8% (nonvolatile content) of a carboxyl group-containing copolymer resin with a solid content acid value of 108.9 mgKOH/g and a weight average molecular weight of 25,000 (in terms of styrene) was obtained.

(Examples 1 to 5 and Comparative Examples 1 to 5)
The ingredients of Examples 1 to 5 and Comparative Examples 1 to 5 shown in Table 1 below were kneaded in a three-roll mill to obtain a curable resin composition.

＊１：電気化学工業（株）製 比表面積０．４ｍ^２／ｇの球状酸化アルミニウム
＊２：電気化学工業（株）製 比表面積０．４～０．５ｍ^２／ｇの球状酸化アルミニウム
＊３：電気化学工業（株）製 比表面積０．５～０．６ｍ^２／ｇの球状酸化アルミニウム
＊４：Ａｄｍａｔｅｃｈｓ社製 比表面積１．０～１．８ｍ^２／ｇの球状酸化アルミニウム
＊５：Ａｄｍａｔｅｃｈｓ社製 比表面積６．５～９．０ｍ^２／ｇの球状酸化アルミニウム
＊６：電気化学工業（株）製 比表面積１０～１２ｍ^２／ｇの球状酸化アルミニウム
＊７：電気化学工業（株）製 比表面積８～１０ｍ^２／ｇの球状酸化アルミニウム
＊８：電気化学工業（株）製 比表面積６～８ｍ^２／ｇの球状酸化アルミニウム
＊９：ＥＶＯＮＩＫ社製 比表面積５５～７５ｍ^２／ｇの超微粒子酸化アルミニウム
＊１０：信越化学工業（株）製シリコン系消泡剤
＊１１：ビック・ケミー・ジャパン（株）製非シリコン系消泡剤
＊１２：ビック・ケミー・ジャパン（株）製湿潤剤
＊１３：２，４－ジアミノ－６－［２’－メチルイミダゾリル－（１’）］－エチル－ｓ－トリアジン
＊１４：ＢＡＳＦ社製の光重合開始剤
＊１５：トリメチロールプロパントリアクリレート
＊１６：ＤＩＣ（株）製フェノールノボラック型エポキシ樹脂
＊１７：三菱ケミカル（株）製ビスフェノールＡ型エポキシ樹脂
なお、＊１～＊９に記載の、各酸化アルミニウム粉末の比表面積は、ＢＥＴ法により測定したメーカー値である。

*1: Made by Denki Kagaku Kogyo Co., Ltd. Spherical aluminum oxide with a specific surface area of 0.4 m ² /g *2: Made by Denki Kagaku Kogyo Co., Ltd. Spherical aluminum oxide with a specific surface area of 0.4 to 0.5 m ² /g *3 : Manufactured by Denki Kagaku Kogyo Co., Ltd. Spherical aluminum oxide with a specific surface area of 0.5 to 0.6 m ² /g *4: Manufactured by Admatechs Spherical aluminum oxide with a specific surface area of 1.0 to 1.8 m ² /g *5: Admatechs Spherical aluminum oxide with a specific surface area of 6.5 to 9.0 m ² /g *6: Made by Denki Kagaku Kogyo Co., Ltd. Spherical aluminum oxide with a specific surface area of 10 to 12 m ² /g *7: Made by Denki Kagaku Kogyo Co., Ltd. Spherical aluminum oxide with a specific surface area of 8 to 10 m ² /g *8: manufactured by Denki Kagaku Kogyo Co., Ltd. Spherical aluminum oxide with a specific surface area of 6 to 8 m ² /g *9: manufactured by EVONIK, with a specific surface area of 55 to 75 m ² /g Fine particle aluminum oxide *10: Silicone defoaming agent manufactured by Shin-Etsu Chemical Co., Ltd. *11: Non-silicon defoaming agent manufactured by BIC Chemie Japan Co., Ltd. *12: Wetting agent manufactured by BIC Chemie Japan Co., Ltd. *13: 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine *14: Photoinitiator manufactured by BASF *15: Trimethylolpropane triacrylate *16 : Phenol novolac type epoxy resin manufactured by DIC Corporation *17: Bisphenol A type epoxy resin manufactured by Mitsubishi Chemical Corporation Note that the specific surface area of each aluminum oxide powder described in *1 to *9 was measured by the BET method. Manufacturer value.

The obtained curable resin composition was evaluated by the following evaluation method. The evaluation results are shown in Table 2.

(Thixotropic ratio evaluation)
The viscosity of the curable resin composition was measured at 25°C at 5 rpm and 50 rpm using a cone plate viscometer TV-30 manufactured by Toki Sangyo Co., Ltd., and the thixotropic ratio was determined as the ratio of the viscosity values at the two rotational speeds. (TI value) was determined. If the thixotropic ratio is less than 1, it is called a dilatancy fluid, if it is larger than 1, it is called a thixotropic fluid, and if it is 1, it is called a Newtonian fluid.If it corresponds to a dilatancy fluid or if the thixotropic ratio is too high, it will flow even if the viscosity is low. Poor quality and printability problems.

(Evaluation of leveling property of coating film surface)
After screen printing the curable resin composition, it was left to stand at room temperature for 5 minutes, and then dried for 20 minutes in a hot air circulation drying oven at 80° C. The smoothness of the coating film surface was observed and evaluated. The evaluation criteria were as follows.
○: Good.
×: Traces of the screen mesh remained clearly.

(Bubble evaluation in paint film)
The cross section of the cured coating film prepared for evaluating the leveling property of the coating film surface was observed using a scanning electron microscope (SEM) for the presence of microbubbles and voids. The evaluation criteria were as follows.
○: There were no microbubbles or voids.
△: There were microbubbles and voids.
×: There were many microbubbles and voids.

(Solvent resistance evaluation)
The thermosetting resin compositions of Examples 1 to 4 and Comparative Examples 1 to 5 were pattern-printed onto a circuit-formed FR-4 substrate by screen printing so that the dry coating film had a thickness of about 30 μm, and the mixture was heated at 150°C. It was cured for 60 minutes.
Further, the thermosetting and photocurable resin composition of Example 5 was pattern-printed on a circuit-formed FR-4 substrate by screen printing so that the dry coating film was about 30 μm, and then a metal halide lamp was used to print a pattern of about 350 nm. After irradiating with an integrated light amount of 2 J/cm ² at a wavelength of 2 J/cm 2 , it was thermally cured at 150° C. for 60 minutes. The obtained substrate was immersed in propylene glycol monomethyl ether acetate for 30 minutes, and after drying, a peel test was performed using a cellophane adhesive tape to evaluate peeling and discoloration of the coating film. The evaluation criteria were as follows.
○: There was no peeling or discoloration.
×: There was peeling and discoloration.

(Heat resistance evaluation)
Using the thermosetting resin compositions of Examples 1 to 4 and Comparative Examples 1 to 5, and the thermosetting and photocurable resin composition of Example 5, curing was performed in the same manner as for solvent resistance. Rosin-based flux was applied to the obtained board, flowed for 10 seconds in a solder bath at 260°C, washed with propylene glycol monomethyl ether acetate, dried, and then subjected to a peel test using cellophane adhesive tape to check for peeling of the coating film. evaluated. The evaluation criteria were as follows.
○: There was no peeling.
×: There was peeling.

(Pencil hardness evaluation)
Using the thermosetting resin compositions of Examples 1 to 4 and Comparative Examples 1 to 5, and the thermosetting and photocurable resin composition of Example 5, curing was performed in the same manner as for solvent resistance. The lead of a pencil from B to 9H was sharpened so that the tip was flat and pressed onto the obtained substrate at an angle of about 45°, and the hardness of the pencil at which the coating film did not come off was recorded.

(Adhesion (checkerboard adhesion) evaluation)
The thermosetting resin compositions of Examples 1 to 4 and Comparative Examples 1 to 5 were pattern-printed on a circuit-formed FR-4 substrate by screen printing so that the dry coating film was about 30 μm, and then heated at 150°C. Cured for 60 minutes.
Further, the thermosetting and photocurable resin composition of Example 5 was pattern-printed on a circuit-formed FR-4 substrate by screen printing so that the dry coating film was about 30 μm, and then a metal halide lamp was used to print a pattern of about 350 nm. After irradiating with an integrated light amount of 2 J/cm ² at a wavelength of 2 J/cm 2 , it was thermally cured at 150° C. for 60 minutes.
Using the obtained substrate in accordance with JIS K5400, 100 1 mm grids (10 x 10) were made on the film of each sample, and transparent adhesive tape (manufactured by Nichiban Co., Ltd., width: 18 mm) was completely covered on the grid. Immediately after adhesion, one end of the tape was held perpendicular to the glass substrate and pulled off momentarily to examine whether peeling occurred in a grid pattern. The evaluation criteria were as follows.
○: No peeling occurred in the grid.
x: Peeling occurred in a grid pattern.

(Withstand voltage measurement and evaluation)
The thermosetting resin compositions of Examples 1 to 4 and Comparative Examples 1 to 5 were screen-printed onto copper-clad laminates so that the dry film thickness was about 40 μm, and cured at 150° C. for 60 minutes.
In addition, the photocurable and thermosetting resin composition of Example 5 was screen printed on a copper clad laminate so that the dry coating film was about 40 μm, and the photocurable and thermosetting resin composition of Example 5 was printed at a wavelength of 350 nm using a metal halide lamp at 2 J/cm. After irradiating with the cumulative light amount of ² , the test substrate was thermally cured at 150° C. for 60 minutes.
Using an AC/DC withstand voltage tester TOS5101 manufactured by Kikusui Electronics Co., Ltd., measurements were taken in AC mode using an electrode with a diameter of 10 mm, and reading a value at which no dielectric breakdown occurred for 60 seconds. Measurements were performed with n=3, and the average value was calculated. The evaluation criteria were as follows.
○: Withstand voltage was 3 kV/100 μm or more.
×: The withstand voltage was less than 3 kV/100 μm.

(Thermal conductivity measurement)
The thermosetting resin compositions of Examples 1 to 4 and Comparative Examples 1 to 5 were screen printed onto rolled copper foil so that the dry coating film had a thickness of about 50 μm, and cured at 150° C. for 60 minutes.
Further, the photocurable and thermosetting resin composition of Example 5 was screen printed on a rolled copper foil so that the dry coating film was about 50 μm, and the photocurable and thermosetting resin composition of Example 5 was printed at 2 J/cm ² at a wavelength of 350 nm using a metal halide lamp. After irradiating with an integrated light amount of , it was thermally cured at 150° C. for 60 minutes.
Thereafter, the thermal conductivity of the cured film obtained by peeling off the rolled copper foil was measured using QTM500 manufactured by Kyoto Electronics Co., Ltd., and the average value of n=3 was determined.

比較例の評価結果は以下の通りである。
＊＊１および＊＊３：
比較例１および３については、最密充填できておらず、空隙があるため熱伝導率が若干低く、耐電圧が悪い結果となった。
＊＊２、＊＊４および＊＊５：
比較例２、４および５については、レベリングが悪く、塗膜表面にピンホールが発生した。塗膜中も消泡性が悪いため熱伝導率が低く、耐電圧特性もない、もしくは低いとの結果となった。

The evaluation results of the comparative example are as follows.
**1 and **3:
In Comparative Examples 1 and 3, the closest packing was not achieved and there were voids, so the thermal conductivity was slightly low and the withstand voltage was poor.
**2, **4 and **5:
In Comparative Examples 2, 4, and 5, leveling was poor and pinholes were generated on the surface of the coating film. The coating film also had poor antifoaming properties, resulting in low thermal conductivity and no or low withstand voltage characteristics.

As is clear from the results shown in Table 2, according to the present invention, regardless of whether it contains a thermosetting or photocurable resin composition, it has high thermal conductivity and good heat dissipation, and also has foam (microfoam). It was possible to provide a high-withstand-voltage, heat-radiating insulating resin composition that can prevent a decrease in withstand voltage characteristics because it does not generate bulbs (bulbs), and does not require mechanical processing such as pressure molding or vacuum pressing.

Claims (6)

A high voltage withstand heat dissipating insulating resin composition comprising (A) highly thermally conductive particles and (B) a curable resin,
The volume occupancy of the highly thermally conductive particles (A) is 60% by volume or more with respect to the total solid content of the high voltage withstand heat dissipating insulating resin composition,
The ratio of the (A) high thermal conductive particles to (A-1) high thermal conductive particles having a specific surface area of 0.2 to 0.6 m ² /g as measured by the BET method and (A-2) as measured by the BET method. Contains highly thermally conductive particles with a surface area of 6.0 to 12.5 m ² /g,
Based on the total weight of the (A) high thermal conductive particles, the high thermal conductive particles (A-2) have a specific surface area of 6.0 to 12.5 m ² /g measured by the BET method in an amount of 5 to 16% by weight. can be,
The (A) high thermal conductive particles are aluminum oxide particles,
Contains both silicone antifoaming agent and non-silicon antifoaming agent,
A high voltage withstand heat dissipating insulating resin composition characterized by being a coating type. The high voltage withstand heat dissipating insulating resin composition according to claim 1, further comprising (C) an organic solvent. The ratio of the (A) high thermal conductive particles to (A-1) high thermal conductive particles having a specific surface area of 0.2 to 0.6 m ² /g as measured by the BET method and (A-2) as measured by the BET method. The high voltage withstand heat dissipating insulating resin composition according to claim 1, characterized in that it consists only of highly thermally conductive particles having a surface area of 6.0 to 12.5 m ² /g. The high withstand voltage according to claim 1, characterized in that the (B) curable resin contains at least one of (B-1) a thermosetting resin and (B-2) a photocurable resin. Heat dissipating insulating resin composition. A cured product obtained by curing the high voltage withstand heat dissipating insulating resin composition according to any one of claims 1 to 4 . An electronic component comprising the cured product according to claim 5 .