阅读说明：本技术 高耐电压散热绝缘性树脂组合物和使用其的电子部件 (High withstand voltage heat-dissipating insulating resin composition and electronic component using same ) 是由 大胡义和 于 2019-07-04 设计创作，主要内容包括：提供：高导热率且散热性良好、而且可以防止耐电压特性的降低、且无需加压成型、真空加压等机械加工的高耐电压散热绝缘性树脂组合物。一种高耐电压散热绝缘性树脂组合物,其特征在于,其含有(A)高导热性颗粒和(B)固化性树脂,前述(A)高导热性颗粒的体积占有率相对于高耐电压散热绝缘性树脂组合物的固体成分总体积为60体积％以上,前述(A)高导热性颗粒含有：(A-1)以BET法测得的比表面积为0.2～0.6m～2/g的高导热性颗粒和(A-2)以BET法测得的比表面积为6.0～12.5m～2/g的高导热性颗粒,相对于前述(A)高导热性颗粒总重量,前述(A-2)以BET法测得的比表面积为6.0～12.5m～2/g的高导热性颗粒为5～16重量％。(Providing: a high-withstand-voltage heat-dissipating insulating resin composition which has high thermal conductivity and excellent heat dissipation properties, can prevent a decrease in withstand voltage characteristics, and does not require mechanical processing such as press molding or vacuum pressing. A high withstand voltage heat-dissipating insulating resin composition comprising (A) highly thermally conductive particles and (B) a curable resin, wherein the volume occupancy of the (A) highly thermally conductive particles is 60 vol% or more based on the total volume of solid components of the high withstand voltage heat-dissipating insulating resin composition, and the (A) highly thermally conductive particles comprise: (A-1) by the BET methodThe specific surface area is 0.2-0.6 m 2 Particles having high thermal conductivity per g and (A-2) having a specific surface area of 6.0 to 12.5m by BET method 2 (ii)/g of highly thermally conductive particles, wherein the specific surface area of the particles (A-2) as measured by the BET method is 6.0 to 12.5m based on the total weight of the particles (A) 2 The highly heat conductive particles are 5 to 16 wt.% based on the total weight of the composition.)

1. A high withstand voltage heat-dissipating insulating resin composition comprising (A) high thermal conductive particles and (B) a curable resin,

the volume occupancy rate of the high thermal conductive particles (A) is 60 vol% or more based on the total volume of the solid components of the high withstand voltage heat dissipation insulating resin composition,

the (A) high thermal conductive particles contain: (A-1) a specific surface area of 0.2 to 0.6m measured by BET method²Particles having high thermal conductivity per g and (A-2) having a specific surface area of 6.0 to 12.5m by BET method²Particles with a high thermal conductivity in a ratio of/g,

the specific surface area of (A-2) measured by BET method is 6.0-12.5 m relative to the total weight of the high thermal conductive particles²The particles with high thermal conductivity per gram are 5 to 16 weightAnd (4) percent of the total amount.

2. The resin composition according to claim 1, further comprising (C) an organic solvent.

3. The resin composition according to claim 1, which is of a coating type.

4. The resin composition according to claim 1, wherein the particles (A) having high thermal conductivity are alumina particles.

5. The resin composition according to claim 1, wherein the specific surface area of the highly heat conductive particles (A) measured by BET method of (A-1) alone is 0.2 to 0.6m²Particles having high thermal conductivity per g and (A-2) having a specific surface area of 6.0 to 12.5m by BET method²High thermal conductivity particles per gram.

6. The high withstand voltage heat-dissipating insulating resin composition according to claim 1, further comprising at least one of (B-1) a thermosetting resin and (B-2) a photocurable resin as the curable resin (B).

7. A cured product obtained by curing the high withstand voltage heat-dissipating insulating resin composition according to any one of claims 1 to 6.

8. An electronic component comprising the cured product according to claim 7.

Technical Field

The present invention relates to a heat-dissipating insulating resin composition having excellent withstand voltage and an electronic component using the same, and more particularly, to a high-withstand-voltage heat-dissipating insulating resin composition having excellent withstand voltage characteristics without lowering thermal conductivity, and an electronic component such as a printed circuit board using the same.

Background

In recent years, reduction of CO has been demanded as a measure for preventing global warming₂In order to cope with exhaust gas of automobiles, development of vehicles using high-power engines, such as electric automobiles and hybrid automobiles, has been advanced. When electric power is supplied from a battery to an engine, a power transistor and a power diode for converting to a high voltage and a high current have a problem of heat generation during operation, and particularly in an electric vehicle of the next generation planned to convert to a further high voltage, the problem of heat generation is expected to become more significant. Therefore, further improvement in high thermal conductivity and high heat dissipation is demanded.

As a printed wiring board having excellent heat dissipation properties, for example, patent document 1 discloses a metal base substrate in which a metal plate of copper, aluminum or the like is used, and a circuit pattern is formed on one surface or both surfaces of the metal plate via an insulating layer of a prepreg, a thermosetting resin composition or the like.

For example, patent document 2 discloses a highly thermally conductive resin cured product containing a filler having a large particle size at a constant ratio, and patent document 3 discloses a highly thermally conductive resin cured product containing a filler having a small particle size at a constant ratio.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 6-224561

Patent document 2: japanese patent laid-open No. 2014-189701

Patent document 3: japanese patent laid-open publication No. 2014-193565

Disclosure of Invention

Problems to be solved by the invention

However, in the metal base substrate according to the invention described in patent document 1, since the electrical insulating layer has low thermal conductivity, the insulating layer needs to be made thin, and as a result, there is a problem that the withstand voltage characteristics of the electrical insulating layer are degraded.

In the highly thermally conductive cured resin according to the inventions described in patent documents 2 and 3, the withstand voltage characteristics are still degraded by fine bubbles (microbubbles) generated in the pores of the filler. Therefore, in order to prevent such a problem and to fill the highly thermally conductive particles at the highest density, machining such as press molding or vacuum pressing is required, which causes problems of labor-consuming work and poor workability.

The present invention has been made in view of the above problems, and a main object thereof is to provide: a high-withstand-voltage heat-dissipating insulating resin composition which has high thermal conductivity and excellent heat dissipation properties, can prevent a decrease in withstand voltage characteristics, and does not require mechanical processing such as press molding or vacuum pressing.

Further, there is provided: an electronic component having a cured product obtained by heat-curing and/or photo-curing the high withstand voltage heat-dissipating insulating resin composition.

Means for solving the problems

The present inventors have conducted intensive studies in order to achieve the aforementioned object. As a result, they found that: the particles (A) are blended with a curable resin (B) to form highly thermally conductive particles (A) having a specific surface area of 0.2 to 0.6m as measured by the BET method²(A-1) high thermal conductive particles in a ratio of (A-1) to (B) g, and a specific surface area of 6.0 to 12.5m by BET method²(A-2) high thermal conductive particles in/g are such that their compounding amount becomes a constant ratio, thereby enabling the most dense filling and the voltage resistance characteristics can be improved without lowering the thermal conductivity, to which the present invention has been completed.

That is, the high withstand voltage heat-dissipating insulating resin composition of the present invention is characterized by containing (a) highly thermally conductive particles and (B) a curable resin, wherein the (a) highly electrically conductive particlesThe volume occupancy rate of the thermal particles is 60 vol% or more based on the total volume of the solid content of the high withstand voltage heat dissipation insulating resin composition, and the high thermal conductive particles (a) contain: (A-1) a specific surface area of 0.2 to 0.6m measured by BET method²Particles having high thermal conductivity per g and (A-2) having a specific surface area of 6.0 to 12.5m by BET method²(ii)/g of highly thermally conductive particles, wherein the specific surface area of the particles (A-2) as measured by the BET method is 6.0 to 12.5m based on the total weight of the particles (A)²The highly heat conductive particles are 5 to 16 wt.% based on the total weight of the composition. The solid content of the composition means that the organic solvent is removed from the composition.

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

In the high withstand voltage heat-dissipating insulating resin composition of the present invention, the high thermal conductive particles (a) are preferably alumina particles.

In the high withstand voltage heat-dissipating insulating resin composition of the present invention, it is preferable that the specific surface area of the high thermal conductive particles (A) measured by the BET method from (A-1) alone is 0.2 to 0.6m²Particles having high thermal conductivity per g and (A-2) having a specific surface area of 6.0 to 12.5m by BET method²High thermal conductivity particles per gram.

The high withstand voltage heat-dissipating insulating resin composition of the present invention preferably contains at least either (B-1) a thermosetting resin or (B-2) a photocurable resin as the curable resin (B).

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

The high withstand voltage heat-dissipating insulating resin composition of the present invention preferably contains a compound having 1 or more ethylenically unsaturated bonds in one molecule as the photocurable resin (B-2), and further contains a photopolymerization initiator.

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

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there can be provided: a high-withstand-voltage heat-dissipating insulating resin composition which has high thermal conductivity and excellent heat dissipation properties, can prevent a decrease in withstand voltage characteristics, and does not require mechanical processing such as press molding or vacuum pressing. Further, there can be provided: an electronic component such as a printed wiring board in which an insulating layer and/or a solder resist layer is formed from a cured product obtained by thermally curing and/or photocuring the high-withstand-voltage heat-dissipating insulating resin composition. The composition of the present invention can be used for filling holes such as via holes and through holes in printed wiring boards.

Detailed Description

The high withstand voltage heat-dissipating insulating resin composition of the present invention is characterized by containing (a) highly heat-conductive particles and (B) a curable resin, wherein the volume occupancy of the (a) highly heat-conductive particles is 60 vol% or more based on the total solid content volume of the high withstand voltage heat-dissipating insulating resin composition, and the (a) highly heat-conductive particles contain: (A-1) a specific surface area of 0.2 to 0.6m measured by BET method²Particles having high thermal conductivity per g and (A-2) having a specific surface area of 6.0 to 12.5m by BET method²(ii)/g of highly thermally conductive particles, wherein the specific surface area of the particles (A-2) as measured by the BET method is 6.0 to 12.5m based on the total weight of the particles (A)²The highly heat conductive particles are 5 to 16 wt.% based on the total weight of the composition. In the BET method for measuring the specific surface area in the present invention, for example, there is a method of measuring actual measurement by the BET one-point method using a full-automatic BET specific surface area measuring apparatus Massorb HM-1201 manufactured by Mountech, ltd.

In the present invention, the specific surface area of the combination of (A-1) measured by the BET method is 0.2 to 0.6m²The particles per gram and (A-2) having a specific surface area of 6.0 to 12.5m by BET method²The particles (A) are high thermal conductive particles (G), and the total amount thereof is 60 vol% or more based on the total volume of the solid components of the high withstand voltage heat dissipating insulating resin composition, thereby improving the thermal conductivity and obtaining sufficient thermal conductivity as a heat dissipating material.

The specific surface area of the coating composition is 0.2 to 0.6m measured by the BET method by containing (A-1)²High thermal conductivity particles/g, so that the thermal conductivity can be improved, but only by this, the withstand voltage thereof is low and is not suitable for an insulating material at a high voltage. Therefore, in the present invention, the (A-2) is blended at a constant ratio (5 to 16% by weight based on the total weight of the (A) highly thermally conductive particles) and has a specific surface area of 6.0 to 12.5m as measured by the BET method²High thermal conductivity particles per gram, thereby improving voltage resistance characteristics. A specific surface area of 6.0 to 12.5m as measured by BET method by compounding (A-2) at a constant ratio²The high thermal conductive particles of the present invention are preferably used in the form of a coating material, and the high withstand voltage heat-dissipating insulating resin composition of the present invention can be applied as a coating material by coating the particles in the form of a coating material so as to be thin, thereby removing fine bubbles adhering to the pores of the filler. Therefore, the high withstand voltage heat-dissipating insulating resin composition of the present invention can achieve both high withstand voltage and high heat-dissipating properties (i.e., high thermal conductivity due to the closest packing of (a) high thermal conductive particles) without performing any machining process that requires a large number of steps and is inferior in workability, such as press molding or vacuum pressing.

The coating composition further comprises a coating composition having a specific surface area between (A-1) and (A-2) measured by the BET method of 1.0 to 1.8m²(iii) the high thermal conductive particles of (A-2) have a specific surface area of 55m, as measured by BET method, which is not improved in withstand voltage²In the case of the highly thermally conductive particles having a thermal conductivity of/g or more, the thixotropy is high, and the pores of the filler are not easily reduced, and therefore, both the thermal conductivity and the withstand voltage characteristics are reduced. Therefore, in the present invention, it is preferable that the (A) highly thermally conductive particles have a specific surface area of 0.2 to 0.6m measured by BET method only from (A-1)²Particles per gram and (A-2) having a specific surface area of 6.0 to 12.5m by BET method²(ii) a particle composition of (A-2) alone, and a specific surface area measured by a BET method of 6.0 to 12.5m²When the highly thermally conductive particles are (a), the withstand voltage characteristics are significantly lower than those of the present invention. Further, the specific surface area measured by the BET method is 0.2 to 0.6m without using (A-1) at all²The particles (A-2) have a specific surface area of 6.0 to 12.5m2/g as measured by the BET method, and therefore, the thermal conductivity is extremely low, and the resin composition does not have the characteristics as a heat-dissipating and insulating resin composition.

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

The highly thermally conductive particles (a) of the present invention have a volume occupancy of 60 vol% or more based on the total volume of solid components of the high withstand voltage heat-dissipating insulating resin composition, and are characterized by containing: (A-1) a specific surface area of 0.2 to 0.6m measured by BET method²Particles having high thermal conductivity per g and (A-2) having a specific surface area of 6.0 to 12.5m by BET method²(ii)/g of highly thermally conductive particles, wherein the specific surface area of the particles (A-2) as measured by the BET method is 6.0 to 12.5m based on the total weight of the particles (A)²The highly heat conductive particles are 5 to 16 wt.% based on the total weight of the composition.

In the present invention, as the material of the high thermal conductive particles (a), a publicly known conventional material can be used as long as it has high thermal conductivity. For example, alumina (Al) can be used₂O₃) Silicon dioxide (SiO)₂) Silicon carbide (SiC), zirconium oxide (ZrO)₂) Titanium oxide (TiO)₂) Magnesium oxide (MgO), mullite (3 Al)₂O₃·2SiO₂) Zircon (among others, ZrO₂·SiO₂) Pansy (2 MgO. multidot.2Al)₂O₃·5SiO₂) Silicon nitride (Si)₃N₄) Manganese oxide (MnO)₂) Iron oxide (Fe)₂O₃) Cobalt oxide (CoO).

Among them, alumina is preferable because it is chemically stable and excellent in insulation properties, and spherical alumina is preferable because it can alleviate the viscosity increase at the time of high filling and is suitable for the closest filling. As a commercially available product of spherical alumina particles, the ratio of (A-1) as measured by the BET methodThe surface area is 0.2 to 0.6m²The highly heat conductive particles are DAW-03 (available from the trade name of electrochemical engineering Co., Ltd., having a specific surface area of 0.5 to 0.6m measured by the BET method)²(g)), DAW-05 (available from electrochemical industries, Ltd., specific surface area measured by BET method of 0.4 to 0.5m²(g)), DAW-07 (a specific surface area measured by BET method, manufactured by electrochemical industries, Ltd., 0.4m²(g)), DAW-45 (product of electrochemical industries, Ltd., specific surface area by BET method of 0.2m²(g)), DAW-70 (product of electrochemical industries, Ltd., specific surface area by BET method of 0.2m²(iii) a specific surface area by BET method of 6.0 to 12.5m for (A-2)²The high thermal conductive particles are AO-509 (manufactured by Admatechs corporation, having a specific surface area of 6.5 to 9.0m measured by the BET method)²(g)), ASFP-20 (product of electrochemical engineering Co., Ltd., specific surface area by BET method of 10 to 12m²(g)), ASFP-25 (available from electrochemical industries, Ltd., specific surface area measured by BET method of 8 to 10m²(g)), ASFP-40 (product of electrochemical engineering Co., Ltd., specific surface area by BET method 6-8 m²,/g), etc.

The highly heat conductive particles (A) of the present invention have a specific surface area of 0.2 to 0.6m as measured by BET method (A-1)²The particles per gram and (A-2) having a specific surface area of 6.0 to 12.5m by BET method²The particles per gram, so that high packing can be achieved.

The highly thermally conductive particles (a) of the present invention are preferably surface-treated with a coupling agent such as a silane coupling agent in order to improve the low water absorption property, thermal shock resistance and crack resistance of the cured product. As the coupling agent, silane-based, titanate-based, aluminate-based, and zircoaluminate-based coupling agents can be used. Among them, silane coupling agents are preferable. Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, N- (2-aminomethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-phenylaminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane, which may be used alone or in combination.

These coupling agents may be prepared by separately mixing (a) highly thermally conductive particles whose surfaces are not treated and a coupling agent, and subjecting (a) highly thermally conductive particles to surface treatment in a composition, but it is preferable to fix the coupling agent by adsorption or reaction on the surfaces of (a) highly thermally conductive particles in advance. At this time, the amount of the coupling agent and the surface treatment method used in the surface treatment are not particularly limited.

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

Examples of the thermosetting resin (B-1) include resins which are cured by heating to exhibit electrical insulation properties, for example, epoxy resins, oxetane resins, melamine resins, and silicone resins, and in the present invention, a thermosetting resin using an epoxy compound and/or an oxetane compound is particularly preferable, and in this case, a curing agent and/or a curing catalyst is further preferably used.

As the epoxy compound, any known and commonly used compound can be used as long as it has 1 or more, preferably 2 or more, epoxy groups in one molecule. Examples of the epoxy resin include compounds having 2 or more epoxy groups in 1 molecule, such as 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) isocyanurate, and tris (2-hydroxyethyl) isocyanurate triglycidyl ester. Further, monoepoxy compounds such as butyl glycidyl ether, phenyl glycidyl ether, and glycidyl (meth) acrylate may be added within a range in which the cured coating film characteristics are not degraded. Further, they may be used alone or in combination of 2 or more depending on the requirement for improvement of the properties of the coating film.

The oxetane compound is a compound containing an oxetane ring as shown in the following general formula (I).

[ solution 1]

(in the formula, R¹Represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. )

Specific examples of the compound include 3-ethyl-3-hydroxymethyloxetane (trade name OXT-101 manufactured by Toyo Seisakusho), 3-ethyl-3- (phenoxymethyl) oxetane (trade name OXT-211 manufactured by Toyo Seisakusho), 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane (trade name OXT-212 manufactured by Toyo Seisakusho Co., Ltd.), 1, 4-bis { [ (3-ethyl-3-oxetanyl) methoxy ] methyl } benzene (trade name OXT-121, manufactured by Toyo Kabushiki Kaisha), bis (3-ethyl-3-oxetanylmethyl) ether (trade name OXT-221, manufactured by Toyo Kabushiki Kaisha), and the like. Further, an oxetane compound of phenol novolac type and the like can be given.

The oxetane compound may be used in combination with the epoxy compound or alone, but is inferior in reactivity to the epoxy compound, and therefore, attention is required to increase the curing temperature and the like.

Examples of the curing agent include polyfunctional phenol compounds, polycarboxylic acids and anhydrides thereof, aliphatic or aromatic primary or secondary amines, polyamide resins, and polymercapto compounds. Among them, polyfunctional phenol compounds, polycarboxylic acids and 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 has 2 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, and vinylphenol copolymer resins are mentioned, and phenol novolac resins are particularly preferable because they have high reactivity and high effect of improving heat resistance. Such a polyfunctional phenol compound undergoes an addition reaction together with the aforementioned epoxy compound and/or oxetane compound in the presence of an appropriate curing catalyst.

The polycarboxylic acid and the acid anhydride thereof are compounds having 2 or more carboxyl groups in one molecule and acid anhydrides thereof, and examples thereof include a copolymer of (meth) acrylic acid, a copolymer of maleic anhydride, and a condensate of a dibasic acid. Examples of commercially available products include Joncryl (trade name group) manufactured by Johnson Polymer, SMA Resin (trade name group) manufactured by ARCO Chemical, and polyazelaic anhydride manufactured by Nissian Chemical Co., Ltd.

Examples of the curing catalyst include compounds serving as curing catalysts for the reaction of an epoxy compound and/or an oxetane compound with a polyfunctional phenol compound and/or a polycarboxylic acid and an anhydride thereof, and compounds serving as polymerization catalysts when a curing agent is not used, for example, tertiary amines, tertiary amine salts, quaternary onium salts, tertiary phosphines, crown ether complexes, phosphonium dipoles, and the like, and they may be arbitrarily selected from them, and they may be used alone or in combination of 2 or more.

Among them, preferred examples thereof include imidazoles such as 2E4MZ, C11Z, C17Z and 2PZ, AZINE compounds such as imidazoles such as 2MZ-A and 2E4MZ-A, isocyanurates of imidazoles such as 2MZ-OK and 2PZ-OK, imidazole methylol substrates such as 2PHZ and 2P4MHZ (the trade names are all made by Sichu chemical Co., Ltd.), dicyandiamide and derivatives thereof, melamine and derivatives thereof, diaminocis-butenenitrile and derivatives thereof, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, bis (hexamethylene) triamine, triethanolamine diaminodiphenylmethane and organic acid dihydrazide, amines such as 1, 8-diazabicyclo [5,4,0] undecene-7 (trade name DBU, made by San-Apro Co., Ltd.), 3, 9-bis (3-aminopropyl) -2,4,8, 10-tetraoxaspiro [5,5] undecane (trade name ATU, Ajinomoto Co., Inc.), and organic phosphine compounds such as triphenylphosphine, tricyclohexylphosphine, tributylphosphine, and methyldiphenylphosphine.

The amount of the curing catalyst to be compounded is a usual amount, and is preferably 0.1 part by mass or more and 10 parts by mass or less, for example, relative to 100 parts by mass of the total of the epoxy compound and/or the oxetane compound.

The photocurable resin (B-2) may be an electrically insulating resin that is cured by irradiation with an active energy ray, and a compound having 1 or more ethylenically unsaturated bonds in one molecule may be preferably used in terms of excellent heat resistance and electrical insulation, and in this case, a photopolymerization initiator is preferably further used.

As the compound having 1 or more ethylenically unsaturated bonds in one molecule, a known and commonly used photopolymerizable oligomer, photopolymerizable vinyl monomer, or the like can be used.

Examples of the photopolymerizable oligomer include unsaturated polyester oligomers and (meth) acrylate oligomers. Examples of the (meth) acrylate-based oligomer include epoxy (meth) acrylates such as phenol novolac epoxy (meth) acrylate, cresol novolac epoxy (meth) acrylate, bisphenol epoxy (meth) acrylate, urethane (meth) acrylate, epoxy urethane (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate, and polybutadiene-modified (meth) acrylate. In the present specification, the term (meth) acrylate refers to a general term of acrylate, methacrylate and a mixture thereof, and the same applies to other similar expressions.

Examples of the photopolymerizable vinyl monomer include known and commonly used ones, for example, styrene derivatives such as styrene, chlorostyrene, and α -methylstyrene; vinyl esters such as vinyl acetate, vinyl butyrate, and vinyl benzoate; vinyl ethers such as vinyl isobutyl ether, vinyl n-butyl ether, vinyl tert-butyl ether, vinyl n-pentyl ether, vinyl isoamyl ether, vinyl n-octadecyl ether, vinyl cyclohexyl ether, ethylene glycol monobutyl vinyl ether, and triethylene glycol monomethyl vinyl ether; (meth) acrylamides such as acrylamide, methacrylamide, N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, N-methoxymmethacrylamide, N-ethoxymethacrylamide and N-butoxymethacrylamide; allyl compounds such as triallyl isocyanurate, diallyl phthalate, and diallyl isophthalate; esters of (meth) acrylic acid such as 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, and the like; hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and pentaerythritol tri (meth) acrylate; alkoxyalkylene glycol mono (meth) acrylates such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; alkylene polyol poly (meth) acrylates such as ethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like; polyoxyalkylene glycol poly (meth) acrylates such as diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol 200 di (meth) acrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane tri (meth) acrylate, and the like; poly (meth) acrylates such as hydroxypivalyl hydroxypivalate di (meth) acrylate; and isocyanurate type poly (meth) acrylates such as tris [ (meth) acryloyloxyethyl ] isocyanurate. These may be used alone or in combination of 2 or more depending on the characteristics of the coating film.

Examples of the photopolymerization initiator include benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and benzyl methyl ketal, and alkyl ethers thereof; acetophenones such as acetophenone, 2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, diethoxyacetophenone, 2-diethoxy-2-phenylacetophenone, 1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinyl-1-propanone; anthraquinones such as methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, and 2-amylanthraquinone; thioxanthones such as thioxanthone, 2, 4-diethylthioxanthone, 2-chlorothioxanthone, 2, 4-dichlorothioxanthone, 2-methylthioxanthone and 2, 4-diisopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzil dimethyl ketal; and benzophenones such as benzophenone and 4, 4-bismethylaminobenzophenone. These may be used alone or in combination of 2 or more, and may further be used in combination with a tertiary amine such as triethanolamine or methyldiethanolamine; and a photoinitiator aid such as a benzoic acid derivative such as ethyl 2-dimethylaminobenzoate or ethyl 4-dimethylaminobenzoate.

When an alkali-developable photocurable resin composition is used as the (B) curable resin, a carboxyl group may be introduced into the compound having an ethylenically unsaturated bond as a component of the (B-2) photocurable resin, or a carboxyl group-containing resin having no ethylenically unsaturated bond may be used in addition to the compound having an ethylenically unsaturated bond.

The high withstand voltage heat-dissipating insulating resin composition of the present invention is preferably a coating type containing (C) an organic solvent. (C) The organic solvent is used for adjusting the composition and the viscosity. Any organic solvent may be used as long as it is a known organic solvent, and for example, ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol diethyl ether, and tripropylene glycol monomethyl ether; esters such as ethyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, naphtha, solvent naphtha, and the like. These organic solvents may be used alone or in combination of 2 or more.

(C) The amount of the organic solvent is preferably 3 to 10 parts by mass per 100 parts by mass of the highly thermally conductive particles (a). (C) When the amount of the organic solvent is in this range, the occurrence of voids can be favorably suppressed during drying of the solvent.

The high withstand voltage heat-dissipating insulating resin composition of the present invention may be added with a wetting/dispersing agent as necessary to facilitate high filling. As such a wetting/dispersing agent, a compound having a polar group such as a carboxyl group, a hydroxyl group, an acid ester, a polymer compound, an acid-containing compound such as a phosphate, a copolymer containing an acid group, a hydroxyl group-containing polycarboxylate, a polysiloxane, a salt of a long-chain polyaminoamide with an acid ester, or the like can be used.

Examples of commercially available wetting/dispersing agents that are particularly suitable for users include Disperbyk (registered trademark) -101, -103, -110, -111, -160, -171, -174, -190, -300, Bykumen (registered trademark), BYK-P105, -P104S, -240 (all manufactured by BYK Japan), EFKA-Polymer 150, EFKA-44, -63, -64, -65, -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, as required: known and commonly used additives such as a known and commonly used coloring agent such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black, naphthalene black, and the like, a known and commonly used thermal polymerization inhibitor such as hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, pyrogallol, phenothiazine, and the like, a known and commonly used thickener such as fine powder silica, organic bentonite, montmorillonite, and the like, a known and commonly used extender such as silica, barium sulfate, talc, clay, and hydrotalcite, and a silicon-based, fluorine-based, polymer-based defoaming agent and/or leveling agent. In the high withstand voltage heat-dissipating insulating resin composition of the present invention, it is preferable to use a combination of a silicon-based defoaming agent and a non-silicon-based defoaming agent because bubbles (microbubbles) at the time of coating are further removed.

The high withstand voltage heat-dissipating insulating resin composition of the present invention is preferably applied to a substrate by a screen printing method or the like while adjusting the viscosity to a value suitable for the application method with the organic solvent (C).

When the (B) curable resin is contained as the (B) curable resin of the high withstand voltage heat dissipating insulating resin composition, the (B-1) thermosetting resin is heated to a temperature of about 140 to 180 ℃ after application, and is thermally cured to obtain a cured coating film.

In the case where the photocurable resin (B-2) is contained as the curable resin (B) of the high-withstand-voltage insulating curable resin composition, a cured coating film can be obtained by irradiating the cured coating film with ultraviolet light using a high-pressure mercury lamp, a metal halide lamp, a xenon lamp, or the like after coating.

When the alkali development type photocurable resin composition containing a mixture of the (B-1) thermosetting resin and the (B-2) photocurable resin is used as the (B) curable resin of the curable resin composition having high withstand voltage insulation properties, the composition is subjected to pattern exposure and development with ultraviolet rays such as a high-pressure mercury lamp, a metal halide lamp, and a xenon lamp after application, and is heated to a temperature of about 140 to 180 ℃ to be thermally cured, thereby obtaining a cured coating film having a pattern shape.

Examples

The present invention will be specifically described by way of examples and comparative examples of the present invention, but the present invention is not limited to the following examples. In the following, unless otherwise specified, all of the "parts" and "%" represent "parts by mass" and "% by mass".

(Synthesis of photopolymerizable oligomer (B-2))

900g of diethylene glycol dimethyl ether and 21.4g of t-butyl peroxy-2-ethylhexanoate (Perbutyl O, manufactured by Nippon fat Co., Ltd.) were put into a 2-liter-volume separable flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen gas inlet tube, and after the temperature was raised to 90 ℃ the mixture was added dropwise to diethylene glycol dimethyl ether over 3 hours, 109.8g of methacrylic acid, 116.4g of methyl methacrylate, and lactone-modified 2-hydroxyethyl methacrylate (Daicel Chemical Industries, Ltd., Placcel FM1) represented by the general formula (I) together with 21.4g of bis (4-t-butylcyclohexyl) peroxydicarbonate (Peroyl TCP, manufactured by Nippon fat Co., Ltd.) and further aged for 6 hours, thereby obtaining a carboxyl group-containing copolymer resin solution. The reaction was carried out under a nitrogen atmosphere.

Then, 363.9g of 3, 4-epoxycyclohexyl methacrylate (Cyclomer A200 manufactured by Daicel Chemical Industries, Ltd.), 3.6g of dimethylbenzylamine and 1.80g of hydroquinone monomethyl ether were added to the above carboxyl group-containing copolymer resin solution, and the mixture was heated to 100 ℃ and stirred to conduct a ring-opening addition reaction of epoxy. After 16 hours, a solution containing 53.8% (nonvolatile content) of a carboxyl group-containing copolymer resin having a solid acid value of 108.9mgKOH/g and a weight average molecular weight of 25000 (in terms of styrene) was obtained.

Examples 1 to 5 and comparative examples 1 to 5

The compounding ingredients of examples 1 to 5 and comparative examples 1 to 5 shown in table 1 below were kneaded by a three-roll mill to obtain curable resin compositions.

[ Table 1]

*1: specific surface area 0.4m manufactured by electrochemical industries Ltd²(ii) spherical alumina of

*2: a specific surface area of 0.4 to 0.5m manufactured by the electrochemical industry Co., Ltd²(ii) spherical alumina of

*3: a specific surface area of 0.5 to 0.6m manufactured by electrochemical industries, Ltd²(ii) spherical alumina of

*4: the specific surface area of 1.0-1.8 m manufactured by Admatechs²(ii) spherical alumina of

*5: the specific surface area of Admatechs is 6.5-9.0 m²(ii) spherical alumina of

*6: a specific surface area of 10 to 12m manufactured by the electrochemical industry Co., Ltd²(ii) spherical alumina of

*7: a specific surface area of 8 to 10m, manufactured by electrochemical industries, Ltd²(ii) spherical alumina of

*8: a specific surface area of 6 to 8m, manufactured by electrochemical industries, Ltd²In terms of/gSpherical alumina

*9: specific surface area of 55-75 m manufactured by EVONIK²Ultrafine particle alumina/g

*10: silicon defoaming agent manufactured by shin-Etsu chemical industry Co., Ltd

*11: BYK Japan non-silicon defoaming agent

*12: wetting agent manufactured by BYK Japan K.K

*13: 2, 4-diamino-6- [2 '-methylimidazolyl- (1') ] -ethyl-s-triazine

*14: photopolymerization initiator manufactured by BASF corporation

*15: trimethylolpropane triacrylate

*16: phenol novolac epoxy resin manufactured by DIC corporation

*17: bisphenol A type epoxy resin manufactured by Mitsubishi Chemical Corporation

The specific surface areas of the respective alumina powders described in 1 to 9 are manufacturer values measured by the BET method.

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

(evaluation of thixotropic ratio)

The viscosity of the curable resin composition was measured at 25 ℃ at 5rpm and 50rpm with a cone and plate viscometer TV-30 manufactured by Toyobo industries, Ltd, and the thixotropic ratio (TI value) which is the ratio of the viscosity values at 2 revolutions was obtained. When the thixotropic ratio is less than 1, the fluid is called an expandable fluid, when the thixotropic ratio is more than 1, the fluid is called a thixotropic fluid, when the thixotropic ratio is 1, the fluid is called a newtonian fluid, and when the thixotropic ratio is too high, the fluid is inferior in fluidity even if the viscosity is low, which causes a problem in printability.

(leveling evaluation of coating film surface)

After the curable resin composition was screen-printed, it was left to stand at room temperature for 5 minutes, and then the smoothness of the coating film surface after drying in a hot air circulation type drying oven at 80 ℃ for 20 minutes was observed and evaluated. The evaluation criteria are as follows.

Good: is good.

X: traces of the wire mesh clearly remain.

(evaluation of air bubbles in coating film)

The cross section of the cured coating film prepared in the leveling evaluation of the coating film surface was observed by a Scanning Electron Microscope (SEM) for the presence or absence of microbubbles and voids. The evaluation criteria are as follows.

Good: no micro bubbles and pores.

And (delta): there are microbubbles and pores.

X: there are a large number of microbubbles, pores.

(evaluation of solvent resistance)

The thermosetting resin compositions of examples 1 to 4 and comparative examples 1 to 5 were pattern-printed on an FR-4 substrate having a circuit formed thereon by screen printing so that the dried coating film became about 30 μm, and cured at 150 ℃ for 60 minutes.

The thermosetting and photocurable resin composition of example 5 was pattern-printed on an FR-4 substrate having a circuit formed thereon by screen printing so that the dried coating film became about 30 μm, and irradiated under a metal halide lamp at a wavelength of 350nm to 2J/cm²Then, heat curing was performed at 150 ℃ for 60 minutes. The obtained substrate was immersed in propylene glycol monomethyl ether acetate for 30 minutes, dried, and then subjected to a peeling test using a cellophane adhesive tape to evaluate the peeling and discoloration of the coating film. The evaluation criteria are as follows.

O: no peeling and color change.

X: peeling and discoloration.

(evaluation of Heat resistance)

The thermosetting resin compositions of examples 1 to 4 and comparative examples 1 to 5 and the thermosetting and photocurable resin compositions of example 5 were cured by the same method as solvent resistance. The obtained substrate was coated with a rosin flux, flowed in a solder bath at 260 ℃ for 10 seconds, washed/dried with propylene glycol monomethyl ether acetate, and then subjected to a peeling test using a cellophane adhesive tape to evaluate the peeling of the coating film. The evaluation criteria are as follows.

O: no peeling.

X: there was peeling.

(evaluation of Pencil hardness)

The thermosetting resin compositions of examples 1 to 4 and comparative examples 1 to 5 and the thermosetting and photocurable resin compositions of example 5 were cured by the same method as solvent resistance. The pencil leads of the B to 9H pencils were cut so that the tips thereof were flat, and the pencil leads were pressed against the obtained substrate at an angle of about 45 °, whereby the hardness of the pencil with the coating film not peeled off was recorded.

(evaluation of adhesion (checkerboard adhesion))

The thermosetting resin compositions of examples 1 to 4 and comparative examples 1 to 5 were pattern-printed on an FR-4 substrate having a circuit formed thereon by screen printing so that the dried coating film became about 30 μm, and cured at 150 ℃ for 60 minutes.

The thermosetting and photocurable resin composition of example 5 was pattern-printed on an FR-4 substrate having a circuit formed thereon by screen printing so that the dried coating film became about 30 μm, and irradiated under a metal halide lamp at a wavelength of 350nm to 2J/cm²After the accumulated light amount of (2), heat curing was performed at 150 ℃ for 60 minutes.

The obtained substrate was subjected to JISK5400 processing to form 100 pieces (10X 10 pieces) of 1mm checkerboard on the coating film of each sample, a transparent adhesive tape (width: 18mm, manufactured by Nichiban corporation) was completely adhered to the checkerboard, and one end of the tape was immediately pulled away while keeping a right angle to the glass substrate, and whether or not peeling occurred in the checkerboard was examined. The evaluation criteria are as follows.

O: no peeling occurred in the checkerboard.

X: peeling occurred in the checkerboard.

(Voltage withstand measurement and evaluation)

The thermosetting resin compositions of examples 1 to 4 and comparative examples 1 to 5 were printed on a copper-clad laminate by screen printing so that the dried coating film became about 40 μm, and cured at 150 ℃ for 60 minutes.

In addition, the photocurable and thermosetting resin composition of example 5 was applied to a copper-clad layerThe laminate was printed by screen printing so that the dried coating film became about 40 μm, and irradiated under a metal halide lamp at a wavelength of 350nm for 2J/cm²After the cumulative light amount of (2), a test substrate was prepared by heat curing at 150 ℃ for 60 minutes.

The value of the non-insulation breakdown within 60 seconds was read and measured using an electrode having a diameter of 10mm in an AC mode using an AC/DC withstand voltage tester TOS5101 manufactured by Chrysanthemum electronics industry. The measurement was performed with n being 3, and the average value was calculated. The evaluation criteria are as follows.

O: the withstand voltage is more than 3kV/100 mu m.

X: the withstand voltage is lower than 3kV/100 μm.

(measurement of thermal conductivity)

The thermosetting resin compositions of examples 1 to 4 and comparative examples 1 to 5 were printed on a rolled copper foil by screen printing so that the dried coating film became about 50 μm, and cured at 150 ℃ for 60 minutes.

The photocurable and thermosetting resin composition of example 5 was printed on a rolled copper foil by screen printing so that the dried coating film became about 50 μm, irradiated under a metal halide lamp with a cumulative light amount of 2J/cm2 at a wavelength of 350nm, and then thermally cured at 150 ℃ for 60 minutes.

Then, the thermal conductivity of the film-like cured product obtained by peeling the rolled copper foil was measured by using QTM500 manufactured by kyoto electronics industries, and the average value of n-3 was obtained.

[ Table 2]

Example 1

Example 2

Example 3

Example 4

Example 5

Comparative example 1

Comparative example 2

Comparative example 3

Comparative example 4

Comparative example 5

Evaluation of thixotropic ratio

1.3

2.2

1.8

1.8

1.9

1.8

6.7

1.2

4.5

3.8

Evaluation of leveling Property of coating film surface

○

○

○

○

○

○

×

○

×

×

Evaluation of air bubbles in coating film

○

○

○

○

○

△

×

△

×

×

Evaluation of solvent resistance

○

○

○

○

○

○

×

○

○

○

Evaluation of Heat resistance

○

○

○

○

○

○

×

○

○

○

Evaluation of Pencil hardness

9H

9H

9H

9H

9H

9H

9H

9H

9H

9H

Evaluation of adhesion

○

○

○

○

○

○

×

○

○

○

Voltage withstand measurement (kV/100 μm)

5.0

8.8

5.5

74

7.6

0.6

Cannot measure

0.9

0.3

Cannot measure

Evaluation of withstand voltage

○

○

○

○

○

×

×

×

×

×

Thermal conductivity (W/mK)

3.2

2.9

3.1

3.0

3.0

2.4

1.2

2.7

2.0

1.8

Evaluation results

**1

**2

**3

**4

**5

The evaluation results of the comparative examples are shown below.

1 and 3:

comparative examples 1 and 3 were not able to be filled to the maximum density and had voids, and therefore had low thermal conductivity and were resistant to voltage differences.

2,4 and 5:

in comparative examples 2,4 and 5, flow leveling was poor and pinholes were generated on the coating film surface. The defoaming property during coating is also poor, and therefore, the thermal conductivity is low, and the withstand voltage characteristics are not good or low.

As is clear from the results shown in table 2, according to the present invention, even when any of thermosetting and photocurable resin compositions is contained, since the resin composition has high thermal conductivity and good heat dissipation properties, and no bubbles (microbubbles) are generated, it is possible to provide: a high withstand voltage heat-dissipating insulating resin composition which can prevent a decrease in withstand voltage characteristics and does not require any mechanical processing such as press molding or vacuum pressing.