JP2011153265A - Resin composition and resin cured product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition affording a homogeneous resin cured product having high electrical insulating properties and heat conductivity, and having excellent moldability, and to provide the homogeneous resin cured product having the high electrical insulating properties and heat conductivity. <P>SOLUTION: There is provided the resin composition including a compound in which a branched chain having a polymerizable group at the terminal is bound to both ends of the main chain, and at least one of the main chain and branched chain has mesogen. The resin cured product is obtained by polymerizing the resin composition. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a resin composition and a cured resin product, and more particularly to a resin composition and a cured resin product used for an insulating sheet.

In recent years, with the increase in functionality, size, and weight of electronic devices, the density of electronic components has been increasing. As a result, the amount of heat generated in the electronic component is remarkably increased, which contributes to a decrease in reliability and life of the component. As described above, the heat problem in the electronic device is a very important problem, and the heat dissipation material used for the countermeasure is required to further improve the heat conductivity.
In the field where electrical insulation is required, cured resin is generally used as a heat dissipation material. As a measure for improving the thermal conductivity of this cured resin, an inorganic filler such as inorganic ceramics with high thermal conductivity is used. The method of adding is common. However, in this method, since it is difficult to obtain sufficient thermal conductivity due to the limitation of the addition amount, it is desired to improve the thermal conductivity of the cured resin itself.

  For the reasons described above, the problem of achieving high thermal conductivity in the resin cured product itself is extremely important, and an epoxy resin having a mesogenic group as a resin cured product with improved thermal conductivity. There is known a resin composition containing selenium (see, for example, Patent Document 1). The cured resin obtained from this resin composition is characterized in that a high thermal conductivity of 0.6 W / m · K or more can be obtained without adding an inorganic filler because the mesogenic skeleton is regularly arranged. It is.

Japanese Patent No. 4118691

However, since the epoxy resin having a mesogenic group described in Patent Document 1 has very high crystallinity, it has a high melting point and low solubility in a solvent. Therefore, in order to mix uniformly with the curing agent for epoxy resin, it is necessary to melt at a high temperature (specifically, a temperature higher than the melting point of the epoxy resin). And when this epoxy resin is mixed with the hardening | curing agent for epoxy resins under high temperature, the hardening reaction of an epoxy resin will advance rapidly and gelatinization time will become short. Therefore, it is difficult to uniformly mix these, and there is a problem that a homogeneous resin cured product cannot be obtained.
Further, when a sheet-like cured resin (that is, an insulating sheet) is produced, a resin composition to which a solvent is added is generally used. The epoxy resin described in Patent Document 1 has solubility in a solvent. Since it is low, there also exists a problem that it is difficult to shape | mold into a sheet form with the resin composition using this epoxy resin.

  Therefore, the present invention has been made to solve the above-described problems, and provides a cured resin product having a high electrical insulation property and high thermal conductivity, and provides a resin composition excellent in moldability. The purpose is to do. Another object of the present invention is to provide a homogeneous resin cured product having high electrical insulation and thermal conductivity.

The present inventors have (1) introducing a predetermined branched chain at both ends of the main chain of the compound to lower the steric symmetry of the compound, thereby lowering the melting point of the compound and / or dissolving the compound in the solvent. (2) By introducing a mesogenic group into at least one of the main chain and branched chain of the compound, the mesogenic skeleton portion is regularly arranged in the cured resin and the thermal conductivity is improved. I found out that I can.
That is, the present invention is characterized in that a branched chain having a polymerizable group at the end is bonded to both ends of the main chain, and at least one of the main chain and the branched chain contains a compound having a mesogenic group. It is a resin composition.
The present invention also provides a cured resin obtained by polymerizing the above resin composition.

  ADVANTAGE OF THE INVENTION According to this invention, the resin composition excellent in the moldability which can give the homogeneous resin hardened | cured material with high electrical insulation and heat conductivity can be provided. Moreover, according to this invention, the homogeneous resin hardened | cured material with high electrical insulation and heat conductivity can be provided.

Embodiment 1 FIG.
The resin composition of the present embodiment contains a compound in which a predetermined branched chain is bonded to both ends of the main chain, and at least one of the main chain and the branched chain has a mesogenic group.
In the present specification, the “mesogen group” means a unit having a structure in which two or more rings (for example, cycloalkane, aromatic ring, etc.) are bonded in a straight chain. The mesogenic group is not particularly limited. Benzylidene aniline, benzyl benzoate, phenyl pyrimidine, phenyl dioxane, benzoyl aniline, tolan, benzophenone, phenyl ether, benzanilide, diphenyl methane, phenyl sulfide, diphenyl sulfoxide, diphenyl sulfone, diphenylamine, naphthalene, anthracene, tetracene, phenanthrene, and derivatives thereof Can be mentioned. Among these mesogenic groups, from the viewpoint of thermal conductivity, phenyl benzoate, biphenyl, benzophenone, phenyl ether, benzanilide, stilbene, diazobenzene, benzylideneaniline, and derivatives thereof are preferable. Moreover, the mesogenic group introduced into the compound is not limited to one type, and may be two or more types.
When at least one of the main chain and the branched chain has a mesogenic group, the compound has improved molecular chain stacking properties in a cured resin (polymer) obtained from the resin composition containing the compound. That is, since the molecular chains in the polymer can be densely arranged, the thermal conductivity of the polymer is improved.

The compound can reduce the steric symmetry of the compound by having a predetermined branched chain bonded to the end of the main chain. Thereby, the melting point of the compound is lowered and / or the solubility of the compound in the solvent is improved, and uniform blending into the resin composition is facilitated.
Moreover, a compound can use a compound as various resin raw materials by having a polymeric group at the terminal of a branched chain. The polymerizable group is not particularly limited, and examples thereof include an epoxy group, a vinyl group, an amino group, a hydroxyl group, an acryloyl group, a cyclohexene group, a methacryloyl group, a cinnamoyl group, an isocyanate group, and a dicarboxylic anhydride group. In particular, these exemplified polymerizable groups are preferable because they are excellent in crosslinking reactivity.
From the viewpoint of stability of the compound, it is preferable that two or more branched chains are bonded to both ends of the main chain. Moreover, all the branched chains may have the same structure, and may have two or more different structures.

  At least one of the straight chain and the branched chain of the compound may have a flexible group. Thereby, melting | fusing point of a compound can be reduced further, and the solubility of the compound with respect to a solvent can be improved further. As used herein, “flexible group” means a flexible functional group that can bend in response to steric hindrance in a compound without inhibiting the arrangement of mesogenic groups. Although it does not specifically limit as a flexible group, For example, the functional group represented by the following formula | equation is mentioned.

  In the above formula, n is an integer of 1 or more. Further, the type of the flexible group in the compound may be one type or two or more types.

  The compound having the structure as described above can be generally prepared by a known synthesis method. For example, after a raw material compound that becomes a main chain or a branched chain is reacted and bonded, a polymerizable group may be introduced at the end of the reaction product. The specific conditions for this reaction vary depending on the raw material compounds used, the reaction method, etc., and therefore cannot be uniquely defined. Therefore, it is necessary to set appropriately according to the raw material compound used, the reaction method, and the like.

In the resin composition of the present embodiment, since the above compound has a low melting point and / or high solubility in a solvent, various resin raw materials (for example, monomers for preparing homopolymers, epoxy resins) , Epoxy resin curing agent, etc.).
When the above compound is used as a monomer for preparing a homopolymer, the terminal polymerizable group in the compound may be a homopolymerizable group (for example, a vinyl group). The resin composition containing this monomer can give a cured resin cured by the reaction between the monomers. Moreover, this resin composition can further contain a polymerization initiator.

The polymerization initiator that can be used in the resin composition is not particularly limited, and for example, an azo initiator, a peroxide initiator, a persulfate initiator, and the like can be used. These polymerization initiators can be used alone or in combination of two or more.
Examples of the azo initiator include 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 2,2′-azobis. (2-amidinopropane) dihydrochloride, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (isobutyronitrile), 2,2′-azobis-2-methylbuty Examples include rhonitrile, 1,1-azobis (1-cyclohexanecarbonitrile), 2,2′-azobis (2-cyclopropylpropionitrile), 2,2′-azobis (methylisobutyrate), and the like.

Examples of the peroxide initiator include benzoyl peroxide, acetyl peroxide, lauroyl peroxide, decanoyl peroxide, dicetyl peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di (2 -Ethylhexyl) peroxydicarbonate, t-butylperoxypivalate, t-butylperoxy-2-ethylhexanoate, dicumyl peroxide and the like.
Examples of the persulfate initiator include potassium persulfate, sodium persulfate, and ammonium persulfate.
The blending amount of the polymerization initiator in this resin composition may be appropriately set according to the components to be used, and is not particularly limited. It is below mass parts.

When using the above compound as an epoxy resin, the terminal polymerizable group in the compound may be an epoxy group. The resin composition containing this epoxy resin can give the resin cured material bridge | crosslinked by reaction with an epoxy resin and the hardening | curing agent for epoxy resins by further mix | blending the hardening | curing agent for epoxy resins.
The curing agent for epoxy resin that can be used in the resin composition is not particularly limited, and examples thereof include alicyclic acid anhydrides such as methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and hymic anhydride. Aliphatic acid anhydrides such as dodecenyl succinic anhydride; aromatic acid anhydrides such as phthalic anhydride and trimellitic anhydride; organic dihydrazides such as dicyandiamide and adipic acid dihydrazide; tris (dimethylaminomethyl) phenol, dimethylbenzylamine 1,8-diazabicyclo (5,4,0) undecene and derivatives thereof, and imidazoles such as 2-methylimidazole, 2-ethyl-4-methylimidazole and 2-phenylimidazole. These epoxy resin curing agents can be used alone or in combination of two or more.

Among the above curing agents for epoxy resins, aromatics such as diaminodiphenylmethane, diaminodiphenylethane, and diaminodiphenylsulfone are used from the viewpoint of improving the molecular alignment of the cured resin (polymer) obtained by polymerizing the resin composition. Group diamines; catechol, methyl catechol, dimethyl catechol, butyl catechol, phenyl catechol, methoxy catechol, pyrogallol, methyl hydroquinone, tetrahydroxybenzene, bromocatechol, 1,2-dihydroxynaphthalene, methyl-1,2-dihydroxynaphthalene, dimethyl- 1,2-dihydroxynaphthalene, butyl-1,2-dihydroxynaphthalene, methoxy-1,2-dihydroxynaphthalene, hydroxy-1,2-dihydroxynaphthalene, dihydroxy-1, -Dihydroxynaphthalene, bromo-1,2-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, methyl-2,3-dihydroxynaphthalene, dimethyl-2,3-dihydroxynaphthalene, butyl-2,3-dihydroxynaphthalene, methoxy-2 , 3-dihydroxynaphthalene, hydroxy-2,3-dihydroxynaphthalene, dihydroxy-2,3-dihydroxynaphthalene, bromo-2,3-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, methyl-1,8-dihydroxynaphthalene, dimethyl -1,8-dihydroxynaphthalene, butyl-1,8-dihydroxynaphthalene, methoxy-1,8-dihydroxynaphthalene, hydroxy-1,8-dihydroxynaphthalene, dihydroxy-1,8-dihydroxy Naphthalene, polyvalent phenolic compounds such as bromo-1,8-dihydroxynaphthalene are preferred.
The blending amount of the curing agent for epoxy resin in this resin composition may be appropriately set according to the components to be used and is not particularly limited, but is generally 0.1 parts by mass or more with respect to 100 parts by mass of the epoxy resin. It is 200 parts by mass or less.

When the above compound is used as a curing agent for an epoxy resin, the terminal polymerizable group in the compound may be a group capable of reacting with the epoxy resin (for example, a hydroxyl group, an amino group, etc.). The resin composition containing this epoxy resin curing agent can give a cured resin cured by the reaction of the epoxy resin curing agent and the epoxy resin by further blending the epoxy resin.
The epoxy resin that can be used in this resin composition is not particularly limited. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, Orthocresol novolac type epoxy resins, phenol novolac type epoxy resins, alicyclic aliphatic epoxy resins, glycidyl-aminophenol type epoxy resins and the like can be mentioned. These epoxy resins can be used individually or in combination of 2 or more types. Among these epoxy resins, biphenyl-type epoxy resins, naphthalene-type epoxy resins, and anthracene-type epoxies from the viewpoint of improving the molecular alignment of the cured resin (polymer) obtained by polymerizing the resin composition Resins are preferred.
The blending amount of the curing agent for epoxy resin in this resin composition may be appropriately set according to the components to be used and is not particularly limited, but is generally 0.1 parts by mass or more with respect to 100 parts by mass of the epoxy resin. It is 200 parts by mass or less.

  Since each of the above resin compositions contains a compound having a mesogenic group, the resin composition has a property that a mesogenic skeleton is regularly arranged to be in a liquid crystal state in a specific temperature range. Examples of the liquid crystal state include a nematic phase, a smectic phase, and a cholesteric phase. Also, a resin cured product (polymer) obtained by polymerizing this resin composition can give a structure in which mesogenic skeletons are regularly arranged as in the liquid crystal state. This arrangement structure is preferably a smectic phase and a nematic phase in which the mesogenic skeleton is oriented in a certain direction. Here, the smectic phase means a state in which the major axis direction of the polymer is aligned in a certain direction and the polymer is arranged in a layered manner. The nematic phase means that the polymer has no order at the center of gravity, but its major axis is aligned in a certain direction. The higher the regularity of such an array structure, the higher the thermal conductivity.

The resin composition of the present embodiment can further contain an inorganic filler from the viewpoint of improving the thermal conductivity of the cured resin.
The inorganic filler that can be used in the resin composition of the present embodiment is not particularly limited, but for example, metal particles such as nickel, tin, aluminum, gold, silver, copper, iron, cobalt, indium, and alloys thereof. Metal oxide particles such as aluminum oxide (alumina), zinc oxide, indium tin oxide (ITO), magnesium oxide, beryllium oxide, titanium oxide; metal nitride particles such as boron nitride, silicon nitride, aluminum nitride; silicon carbide, Examples thereof include carbon compound particles such as graphite, diamond, amorphous carbon, carbon black, and carbon fiber; and silica compound powders such as quartz and quartz glass. These inorganic fillers can be used alone or in combination of two or more. Among these inorganic fillers, from the viewpoint of insulating properties of the cured resin, aluminum oxide, zinc oxide, magnesium oxide, beryllium oxide, titanium oxide, boron nitride, silicon nitride, aluminum nitride, diamond, quartz, quartz glass Etc. are preferable.

The average particle size of the inorganic filler is preferably 0.1 μm or more and 150 μm or less, more preferably 3 μm or more and 120 μm or less. When the average particle size of the inorganic filler is less than 0.1 μm, the inorganic filler is aggregated, so that it may be difficult to disperse the inorganic filler. On the other hand, when the average particle size of the inorganic filler exceeds 150 μm, surface roughness of the cured resin product may easily occur when molded into a sheet shape.
The blending ratio of the inorganic filler in the resin composition of the present embodiment is such that the inorganic filler is preferably 20% by volume or more and 80% by volume or less, more preferably in the resin cured product (that is, the solid content of the resin composition). It is desirable that the ratio be 30 volume% or more and 70 volume% or less. If it is the ratio of this range, when shape | molding a resin composition in a sheet form, while being excellent in workability | operativity, the thermal conductivity of a resin cured material can be improved further. If the proportion of the inorganic filler in the cured resin is less than 20% by volume, a cured resin having desired thermal conductivity may not be obtained. On the other hand, when the ratio of the inorganic filler in the cured resin exceeds 80% by volume, it becomes difficult to uniformly disperse the inorganic filler in the cured resin when the sheet-shaped cured resin is produced. May cause troubles in formability and formability.

In addition, the inorganic filler can be subjected to a coupling treatment for the purpose of improving the wettability of the inorganic filler, reinforcing the interface between the resin component and the inorganic filler, and improving the dispersibility of the inorganic filler. Examples of coupling agents that can be used for this treatment include γ-glycidoxypropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane. , Γ-mercaptopropyltrimethoxysilane and the like. These coupling agents can be used alone or in combination of two or more.
The amount of the coupling agent used may be appropriately set according to the resin component and the type of the coupling agent, and is not particularly limited, but is generally 0.01 parts by mass or more per 100 parts by mass of the resin component. It is below mass parts.

The resin composition of the present embodiment can be molded into a desired shape and then heated and polymerized to obtain a cured resin product having the desired shape. In particular, in the case of producing a sheet-like cured resin, the resin composition of the present embodiment may be applied to an alignment substrate and dried, and then heated and polymerized.
The coating method on the alignment substrate is not particularly limited, and either a melting method or a solution method may be adopted, but a solution method is preferable from the viewpoint of workability. Moreover, when coating by a solution method, suitable coating machines, such as a bar coater, a multicoater, a spinner, a roll coater, can be used. Moreover, it is appropriate to use the casting method from the viewpoint of the surface quality of the cured resin.

When the solution method is used, a solvent can be added to the resin composition of the present embodiment. Examples of the solvent include, but are not limited to, halogenated hydrocarbons such as chloroform, dichloromethane, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, and chlorobenzene; phenols such as phenol and parachlorophenol; benzene, toluene, xylene, methoxy Aromatic hydrocarbons such as benzene, anisole and 1,2-dimethoxybenzene; acetone; ethyl acetate; tert-butyl alcohol; glycerin; ethylene glycol; triethylene glycol; ethylene bricol monomethyl ether; Butyl cellosolve; 2-pyrrolidone; N-methyl-2-pyrrolidone; pyridine; triethylamine; tetrahydrofuran; Le formamide; dimethylacetamide; dimethylsulfoxide; acetonitrile; butyronitrile; carbon disulfide; methyl ethyl ketone; cyclohexanone; cyclopentanone and the like. These solvents can be used alone or in combination of two or more.
Although content of the solvent in the resin composition of this Embodiment is not specifically limited, Generally it is 50 to 70 mass%.

The resin composition coated on the alignment substrate can be dried at room temperature, but may be heated to 80 ° C. or higher and 150 ° C. or lower as necessary to promote solvent volatilization.
The heating temperature for polymerizing the resin composition needs to be appropriately set according to the components to be used, but is generally 60 ° C. or higher and 280 ° C. or lower. Similarly, the polymerization time needs to be appropriately set according to the components used and the amount of the resin composition.

Since the cured resin obtained from the resin composition of the present embodiment has high thermal conductivity and electrical insulation, it can be used as an insulating sheet that is generally used as a heat dissipation material for electronic devices, particularly power modules. it can.
When the cured resin is used as an insulating sheet, the thickness of the insulating sheet is preferably 20 μm or more and 800 μm or less, more preferably 30 μm or more and 300 μm or less. When the thickness of the insulating sheet is less than 20 μm, when the insulating sheet is sandwiched between the members, the followability to the unevenness of the sandwiching surface is insufficient, and the interfacial thermal resistance may increase. On the other hand, if the thickness of the insulating sheet exceeds 800 μm, the heat transfer distance becomes long, and the thermal resistance may increase.

EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated concretely, this invention is not limited to the following Example.
Example 1
300 mL of toluene and 19.02 g (100 mmol) of p-toluenesulfonic acid monohydrate were placed in an eggplant type flask, and azeotropic dehydration was performed using a Dean-Stark trap. Next, 11.22 g (100 mmol) of 4-dimethylaminopyridine was dissolved by heating in 125 mL of toluene, and this solution was added to the azeotropic dehydrated solution obtained above and stirred for 1 hour. did. Thereafter, this solution was concentrated, and the precipitate was recrystallized with 300 mL of dichloroethane to obtain 4- (dimethylamino) pyridinium-4-toluenesulfonate as white needle crystals.
Next, 14.97 g (70 mmol) of 4- (4-hydroxyphenyl) benzoic acid and 38.64 g (140 mmol) of tetrabutylammonium hydroxide 40% aqueous solution were dissolved in 140 mL of tetrahydrofuran. Next, a solution of 8.46 g (70 mmol) of allyl bromide in 30 mL of tetrahydrofuran was added dropwise to this solution while stirring with cooling in an ice bath. The solution was stirred overnight at room temperature, then concentrated and added to 1 L of water. Next, 150 mL of 1N aqueous hydrochloric acid was gradually added to the solution while stirring and cooling the solution in an ice bath. The precipitate produced thereby was filtered off, and the residue was washed with methanol and dried under vacuum. The residue was recrystallized with 1.5 L of ethanol to obtain 12.63 g of white crystalline 4 ′-(allyloxy) biphenyl-4-carboxylic acid.

Next, to 100 mL of thionyl chloride, 2-3 drops of dimethylformamide and 12.62 g (50 mmol) of 4 ′-(allyloxy) biphenyl-4-carboxylic acid were added and overnight at 40 ° C. under nitrogen atmosphere. Heating and stirring were performed. Then, excess thionyl chloride was distilled off under reduced pressure, 20 mL of n-hexane was added, and the remaining thionyl chloride was distilled off under reduced pressure three times. Thereafter, recrystallization was performed using 500 mL of n-hexane to obtain 12.63 g of 4 ′-(allyloxy) biphenyl-4-carbonyl chloride as white crystals.
Next, 13.41 g (100 mmol) of 2,2-bis (hydroxymethyl) propionic acid was added to 50 mL of acetone, and then 15.62 g (150 mmol) of 2,2-dimethoxypropane was dissolved therein. .95 g (5 mmol) of p-toluenesulfonic acid monohydrate was added. After the solution was stirred at room temperature for 2 hours, the solution was neutralized by adding 1.2 mL of ethanol / aqueous ammonia (50 vol% / 50 vol%). And after concentrating this solution under reduced pressure at room temperature, 250 mL dichloromethane was thrown in and it wash | cleaned twice with 20 mL water. Magnesium sulfate was added to the dichloromethane solution for dehydration, and then the solvent was distilled off under reduced pressure with an evaporator to obtain 10.41 g of isopropylidene-2,2-bis (methoxy) propionic acid as a white solid.

Next, 1.86 g (10 mmol) of 4,4′-biphenol, 3.66 g (21 mmol) of isopropylidene-2,2-bis (methoxy) propionic acid, and 1.14 g (4 mmol) in 40 mL of dichloroethane. 4- (dimethylamino) pyridinium-4-toluenesulfonate was dissolved. Then, 5.16 g (25 mmol) of N, N′-dicyclohexylcarbodiimide was further added to this solution, and the mixture was stirred overnight at room temperature under a nitrogen atmosphere. Then, insoluble matter was removed by filtering, and a white solid was obtained by removing the solvent from the filtrate. By recrystallizing this white solid using 150 mL of n-hexane, white needle-shaped biphenyl-4,4′-diylbis (2,2,5-trimethyl-1,3-dioxane-5- 3.21 g of carboxylate) was obtained.
Next, 10.00 g (20 mmol) of biphenyl-4,4′-diylbis (2,2,5-trimethyl-1,3-dioxane-5-carboxylate) is added to 400 mL of methanol and dissolved by heating. I let you. And after cooling this solution to room temperature, 3 tablespoons of ion exchange resin (Dowex (registered trademark)) was added and stirred overnight. Thereafter, 500 mL of methanol was added to dissolve the crude product. Then, the ion exchange resin is removed from the mixture by filtration using a glass filter, and the filtrate is concentrated to give white solid biphenyl-4,4′-diylbis (3-hydroxy-2- (hydroxymethyl) -2. -Methylpropanoate) was obtained in an amount of 8.31 g.

  Next, 4.18 g (10 mmol) of biphenyl-4,4′-diylbis (3-hydroxy-2- (hydroxymethyl) -2-methylpropanoate) and a catalytic amount (about 0.4 g) were added to 60 mL of pyridine. N, N-dimethyl-4-aminopyridine and 13.64 g (50 mmol) of 4 ′-(allyloxy) biphenyl-4-carbonyl chloride are added, and the mixture is heated and stirred overnight at 100 ° C. under a nitrogen atmosphere. Reacted. After cooling the reaction product to room temperature, a 2.5% by mass aqueous sodium hydrogen carbonate solution was added for reprecipitation, and the mixture was stirred overnight. Next, the precipitate is filtered, washed with methanol, and dried under reduced pressure, whereby 2,2 ′-(biphenyl-4,4) which is a white solid vinyl compound represented by the following formula (1). '-Diylbis (oxy)) bis (oxomethylene) bis (2-methylpropane-3,2,1-triyl) tetrakis (4'-(allyloxy) biphenyl-4-carboxylate) was obtained.

The structure of the vinyl compound thus synthesized was confirmed by infrared spectroscopic analysis and ¹ H-NMR and ¹³ C-NMR measurements. Further, the melting point of this vinyl compound was measured using differential scanning calorimetry (DSC) under a temperature rising rate of 10 ° C./min. The melting point results are shown in Table 1. In the following examples, the melting point was measured in the same manner as in this method.
Next, 10 g of this vinyl compound is placed in an aluminum petri dish, and 0.012 g of 2,2′-azobisisobutyronitrile (AIBN) as a polymerization initiator and 5 ml of cyclopentanone as a solvent are mixed with stirring. Thus, a uniform resin composition was prepared. This resin composition was polymerized by heating in an oven at 170 ° C. for 4 hours to obtain a homogeneous cured resin. When this cured resin was observed using a polarizing microscope, the arrangement of molecular chains in the polymer was confirmed.

(Example 2)
12.180 g (9 mmol) of the vinyl compound represented by the above formula (1) was dissolved in 180 mL of chloroform. While this solution was cooled and stirred in an ice bath, 18.60 g (108 mmol) of m-chloroperbenzoic acid was added to this solution little by little over 1 hour, and then stirred at room temperature for 96 hours. After adding chloroform to this solution, it was washed with 400 mL of 5 mass% sodium sulfite aqueous solution and then washed several times with saturated saline. And after adding magnesium sulfate to chloroform solution (organic phase) and dehydrating, the solvent was removed and yellow solid was obtained. This yellow solid was purified by column chromatography using chloroform as an eluent, and 2,2 ′-(biphenyl-4,4′-diylbis (oxy)), which is an epoxy resin represented by the following formula (2). Bis (oxomethylene) bis (2-methylpropane-3,2,1-triyl) tetrakis (4 ′-(glycidyloxy) biphenyl-4-carboxylate) was obtained.

The structure of the epoxy resin thus synthesized was confirmed by infrared spectroscopic analysis and ¹ H-NMR and ¹³ C-NMR measurements. Table 1 shows the melting point results of this epoxy resin.
Next, 10 g of this epoxy resin was placed in an aluminum petri dish placed on a hot plate maintained at 160 ° C., and 2.08 g of a diaminodiphenylmethane (DDM) curing agent previously dissolved in an oven at 150 ° C. and cyclohexane as a solvent. A uniform resin composition was prepared by adding 5 ml of pentanone and stirring and mixing. This resin composition was polymerized by heating in an oven at 180 ° C. for 4 hours to obtain a homogeneous cured resin product. When this cured resin was observed using a polarizing microscope, the arrangement of molecular chains in the polymer was confirmed.

(Example 3)
To 400 mL of dimethylformamide, 27.20 g (100 mmol) of 1,8-dibromooctane, 110.11 g (1000 mmol) of hydroquinone, and 41.46 g (300 mmol) of potassium carbonate were added, and a nitrogen stream was applied at 150 ° C. Stir overnight. The solution was then added to water and reprecipitated. And after filtering a deposit, it washed with water several times and recrystallized using toluene. Subsequently, 4,4 ′-(octane-1,8-diylbis (oxy)) diphenol was obtained by recrystallization using ethanol.
Next, in 150 mL of dichloroethane, 10.00 g (30 mmol) of 4,4 ′-(octane-1,8-diylbis (oxy)) diphenol, 11.07 g (64 mmol) of isopropylidene-2,2-bis. (Methoxy) propionic acid and 3.44 g (12 mmol) of 4- (dimethylamino) pyridinium-4-toluenesulfonate were dissolved. Subsequently, 15.61 g (76 mmol) of N, N′-dicyclohexylcarbodiimide was added to this solution, and the mixture was stirred overnight at room temperature under a nitrogen atmosphere. Thereafter, insoluble matters were removed by filtration, and the solvent was distilled off to obtain a white solid. This white solid was purified by column chromatography using chloroform as an eluent, and 4,4 ′-(octane-1,8-diylbis (oxy)) bis (4,1-phenylene) bis (2,2,2). 5-trimethyl-1,3-dioxane-5-carboxylate).

Next, 6.43 g (10 mmol) of 4,4 ′-(octane-1,8-diylbis (oxy)) bis (4,1-phenylene) bis (2,2,5-trimethyl-) was added to 200 mL of acetone. 1,3-dioxane-5-carboxylate) was added and dissolved, and then 3 tablespoons of ion exchange resin (Dawex (registered trademark)) was added and stirred overnight at room temperature. Thereafter, the ion exchange resin is removed from the mixture by filtration using a glass filter, and the filtrate is concentrated to obtain 4,4 ′-(octane-1,8-diylbis (oxy)) bis (4, 4,3) as a white solid. 5.57 g of 1-phenylene) bis (3-hydroxy-2- (hydroxymethyl) -2-methylpropanoate) was obtained.
Next, 5.63 g (10 mmol) of 4,4 ′-(octane-1,8-diylbis (oxy)) bis (4,1-phenylene) bis (3-hydroxy-2- (hydroxy) was added to 60 mL of pyridine. Methyl) -2-methylpropanoate), catalytic amount (about 0.4 g) of N, N-dimethyl-4-aminopyridine, 13.64 g (50 mmol) of 4 ′-(allyloxy) biphenyl-4-carbonyl chloride And stirred at 100 ° C. overnight under a nitrogen atmosphere. After cooling this solution to room temperature, 2.5 mass% sodium hydrogencarbonate aqueous solution was added and reprecipitated, and it stirred as it was overnight. Next, the precipitate was filtered, washed with methanol, and the resulting white solid was dried under reduced pressure. The solid is purified by column chromatography using chloroform as an eluent, whereby 2,2 ′-(4,4 ′-(octane-), which is a vinyl compound represented by the following formula (3). 1,8-diylbis (oxy)) bis (4,1-phenylene)) bis (oxy) bis (oxomethylene) bis (2-methylpropane-3,2,1-triyl) tetrakis (4 ′-(allyloxy) Biphenyl-4-carboxylate) was obtained.

The structure of the vinyl compound thus synthesized was confirmed by infrared spectroscopic analysis and ¹ H-NMR and ¹³ C-NMR measurements. The results of melting points of this vinyl compound are shown in Table 1.
Next, 10 g of this vinyl compound was put into an aluminum petri dish placed on a hot plate maintained at 155 ° C., and 0.011 g of 2,2′-azobisisobutyronitrile (AIBN) was added as a polymerization initiator. A uniform resin composition was prepared by stirring and mixing. This resin composition was polymerized by heating in an oven at 180 ° C. for 4 hours to obtain a homogeneous cured resin product. When this cured resin was observed using a polarizing microscope, the arrangement of molecular chains in the polymer was confirmed.

Example 4
In 180 mL of chloroform, 13.57 g (9 mmol) of the vinyl compound represented by the above formula (3) was dissolved. While this solution was cooled and stirred in an ice bath, 18.60 g (108 mmol) of m-chloroperbenzoic acid was added to this solution little by little over 1 hour, and then stirred at room temperature for 96 hours. After adding chloroform to this solution, it was washed with 400 mL of 5% by mass aqueous sodium sulfite solution, then washed with 400 mL of 2.5% by mass aqueous sodium hydrogen carbonate solution, and further washed several times with saturated saline. . Magnesium sulfate was added to the chloroform solution (organic layer) for dehydration, and then the solvent was removed to obtain a yellow solid. This yellow solid was purified by column chromatography using chloroform as an eluent, and was 2,2 ′-(4,4 ′-(octane-1,8-) which is an epoxy resin represented by the following formula (4). Diylbis (oxy)) bis (4,1-phenylene)) bis (oxy) bis (oxomethylene) bis (2-methylpropane-3,2,1-triyl) tetrakis (4 '-(glycidyloxy) biphenyl-4- Carboxylate) was obtained.

The structure of the epoxy resin thus synthesized was confirmed by infrared spectroscopic analysis and ¹ H-NMR and ¹³ C-NMR measurements. Table 1 shows the melting point results of this epoxy resin.
Next, 10 g of this epoxy resin was placed in an aluminum petri dish placed on a hot plate maintained at 175 ° C., and 1.89 g of a diaminodiphenylmethane (DDM) curing agent previously dissolved in an oven at 150 ° C. was added and stirred. A uniform resin composition was prepared by mixing. The resin composition was polymerized by heating in an oven at 175 ° C. for 4 hours to obtain a homogeneous cured resin. When this cured resin was observed using a polarizing microscope, the arrangement of molecular chains in the polymer was confirmed.

(Example 5)
To a 500 mL eggplant flask, 200 mL of dichloroethane, 35.40 g (196 mmol) of 6-bromo-1-hexanol, 21.76 g (215 mmol) of triethylamine, and 50 mg of dimethylaminopyridine were added and stirred in an ice bath. . To this solution, 30.94 g (205 mmol) of tert-butyldimethylsilyl chloride was slowly added, followed by stirring at room temperature for 12 hours. Thereafter, insoluble matters were removed by filtration, and the filtrate was washed twice with saturated saline. Sodium sulfate was added to the filtrate (organic phase) for dehydration, and then the solvent was distilled off to obtain a pale yellow liquid. The pale yellow liquid was purified by column chromatography using chloroform as an eluent to obtain 9.00 g of (6-bromohexyloxy) (tert-butyl) dimethylsilane.
Next, 14.97 g (70 mmol) of 4- (4-hydroxyphenyl) benzoic acid and 38.64 g (140 mmol) of 40% by mass aqueous solution of tetrabutylammonium hydroxide were dissolved in 140 mL of tetrahydrofuran. While cooling and stirring the solution in an ice bath, 30 mL of a tetrahydrofuran solution of 8.46 g (70 mmol) of allyl bromide was added dropwise to this solution. The solution was then stirred at room temperature overnight, concentrated and added to 1 L of water. Next, 150 mL of aqueous hydrochloric acid (1N) was gradually added to the solution while stirring and cooling the solution in an ice bath. Then, after the precipitate was filtered off, the precipitate was washed with a small amount of methanol and dried under vacuum. Thereafter, recrystallization was performed using 1.5 L of ethanol to obtain 12.63 g of 4 ′-(allyloxy) biphenyl-4-carboxylic acid as white crystals.

Next, to 100 mL of thionyl chloride, add 2-3 drops of dimethylformamide and 12.62 g (50 mmol) of 4 ′-(allyloxy) biphenyl-4-carboxylic acid, and overnight at 40 ° C. under a nitrogen stream. Heating and stirring were performed. Thereafter, excess thionyl chloride was distilled off under reduced pressure, 20 mL of n-hexane was added, and the remaining thionyl chloride was distilled off under reduced pressure three times. Thereafter, recrystallization was performed using 500 mL of n-hexane to obtain 12.63 g of 4 ′-(allyloxy) biphenyl-4-carbonyl chloride as white crystals.
Next, 110 mL of ethanol and 4.79 g (29 mmol) of 1,4-benzenediboronic acid were added to and dissolved in a 300 mL three-necked flask equipped with a reflux tube and a nitrogen introduction tube. Subsequently, 15.71 g (64 mmol) of 1-bromo-3,4,5-trimethoxybenzene was added to the solution and dissolved again by stirring. Furthermore, 2N sodium carbonate aqueous solution was added to the solution, and nitrogen bubbling was performed for 20 minutes with stirring. Next, 3.68 g (3 mmol) of tetrakis (triphenylphosphine) palladium (0) was quickly added to the solution and stirred at 85 ° C. for 36 hours under a nitrogen stream. Thereafter, this solution was distilled off under reduced pressure, and the precipitated solid was dissolved in 300 mL of dichloromethane, and washed twice with 50 mL of water. After adding magnesium sulfate to this dichloromethane solution (organic phase) for dehydration, the solvent was distilled off under reduced pressure using an evaporator to obtain a yellow solid. This yellow solid was heated and washed twice with 100 mL of methanol to obtain 3,3 ″, 4,4 ″, 5,5 ″ -hexamethoxy-1,1 ′, 4 ′, 1 ″ -terphenyl. .30 g was obtained.

Next, 7.39 g (18 mmol) of 3,3 ″, 4,4 ″, 5,5 ″ -hexamethoxy-1,1 ′ was added to a 500 mL three-necked flask equipped with a dropping funnel, a nitrogen inlet tube and an alkali trap. , 4 ′, 1 ″ -terphenyl and 300 mL of dichloroethane were added, and nitrogen substitution was performed while stirring. Subsequently, 40.59 g (163 mmol) of boron tribromide was slowly added to the three-necked flask in an ice bath using a dropping funnel, followed by stirring at room temperature for 12 hours. The solution was then slowly added to 500 mL of water and stirred for 1 hour. Then, the precipitate is filtered and washed with water to obtain 5.5 g of 3,3 ″, 4,4 ″, 5,5 ″ -hexahydroxy-1,1 ′, 4 ′, 1′-terphenyl. It was.
Next, 10 mL of dehydrated dimethylformamide, 5.31 g (18 mmol) of (6-bromohexyloxy) (tert-butyl) dimethylsilane, 0.989 g was added to a 30 mL three-necked eggplant flask equipped with a nitrogen inlet tube and a reflux tube. (3 mmol) 3,3 ″, 4,4 ″, 5,5 ″ -hexahydroxy-1,1 ′, 4 ′, 1 ″ -terphenyl, 7.46 g (54 mmol) dry potassium carbonate, 50 mg Potassium iodide was added to perform nitrogen substitution. Subsequently, the mixture was stirred at 90 ° C. for 36 hours under a nitrogen stream. Thereafter, the precipitated brown solid was filtered off and washed with water. The obtained solid was dissolved in dichloromethane, magnesium sulfate was added to the solution for dehydration, and then the solvent was distilled off under reduced pressure. The obtained solid was purified by column chromatography using a mixed solvent of chloroform and n-hexane (volume ratio 1: 9) as an eluent to obtain 3,3 ″, 4,4 ″, 5,5 ″ -hexa. 2.00 g of (6- (tert-butyldimethylsilyloxy) hexyloxy) -1,1 ′, 4 ′, 1 ″ -terphenyl was obtained.

Next, a 30 mL three-necked eggplant flask equipped with a dropping funnel was charged with 2 mL of dehydrated tetrahydrofuran and 1.61 g (1 mmol) of 3,3 ″, 4,4 ″, 5,5 ″ -hexa (6- (tert- Butyldimethylsilyloxy) hexyloxy) -1,1 ′, 4 ′, 1 ″ -terphenyl was added and dissolved. Subsequently, 18 mL (18 mmol) of 1N tetrabutylammonium fluoride-containing tetrahydrofuran solution was slowly added dropwise to the three-necked eggplant flask using an addition funnel in an ice bath, and the mixture was stirred at room temperature for 12 hours. Then, tetrahydrofuran was depressurizingly distilled and extraction was performed using diethyl ether. Then, magnesium sulfate was added to the diethyl ether solution (organic phase) for dehydration, and the solvent was distilled off under reduced pressure to obtain a white solid. By recrystallizing this white solid using 3 mL of ethyl acetate, 3,3 ″, 4,4 ″, 5,5 ″ -hexa (6-hydroxyhexyloxy) -1,1 ′, 4 ′, 0.65 g of 1 "-terphenyl was obtained.
Next, to a 10 mL eggplant flask, 1.5 mL of tetrahydrofuran, 0.10 g (0.11 mmol) of 3,3 ″, 4,4 ″, 5,5 ″ -hexa (6-hydroxyhexyloxy) -1, 1 ′, 4 ′, 1 ″ -terphenyl, 0.46 g (4.6 mmol) triethylamine, and 18 mg dimethylaminopyridine were added and dissolved. Subsequently, 0.21 g (0.78 mmol) of 4 ′-(allyloxy) biphenyl-4-carbonyl chloride was added to the eggplant flask little by little in an ice bath to cause a reaction. After completion of the reaction, the solvent was distilled off under reduced pressure, and the precipitated solid was filtered off. This solid was purified by column chromatography using dichloroethane as an eluent, and 3,3 ″, 4,4 ″, 5,5 ″ -hexa (6-) which is a vinyl compound represented by the following formula (5). (4 ′-(Allyloxy) biphenylcarbonyloxy) hexyloxy) -1,1 ′, 4 ′, 1 ″ -terphenyl was obtained.

The structure of the vinyl compound thus synthesized was confirmed by infrared spectroscopic analysis and ¹ H-NMR and ¹³ C-NMR measurements. The results of melting points of this vinyl compound are shown in Table 1.
Next, 10 g of this vinyl compound was put into an aluminum petri dish placed on a hot plate maintained at 110 ° C., and 0.007 g of 2,2′-azobisisobutyronitrile (AIBN) was added as a polymerization initiator. A uniform resin composition was prepared by stirring and mixing. This resin composition was polymerized by heating in an oven at 140 ° C. for 4 hours to obtain a uniform cured resin. When this cured resin was observed using a polarizing microscope, the arrangement of molecular chains in the polymer was confirmed.

(Example 6)
In a 10 mL eggplant flask, 4 mL of chloroform and 0.93 g (0.40 mmol) of the vinyl compound represented by the above formula (5) were dissolved. While this solution was cooled and stirred in an ice bath, 1.26 g (7.3 mmol) of m-chloroperbenzoic acid was added little by little over 30 minutes, and then stirred at room temperature for 36 hours. Chloroform was added to this solution, followed by washing with 3 mL of 5 mass% aqueous sodium sulfite solution, then with 10 mL of 2.5 mass% aqueous sodium hydrogen carbonate solution, and further with saturated brine several times. . Magnesium sulfate was added to the chloroform solution (organic phase) for dehydration, and then the solvent was distilled off to obtain a yellow solid. The yellow liquid is purified by column chromatography using chloroform as an eluent to obtain 3,3 ″, 4,4 ″, 5,5 ″ − which is an epoxy resin represented by the following formula (6). 0.53 g of hexa (6- (4 ′-(glycidyloxy) biphenylcarbonyloxy) hexyloxy) -1,1 ′, 4 ′, 1 ″ -terphenyl was obtained.

The structure of the epoxy resin thus synthesized was confirmed by infrared spectroscopic analysis and ¹ H-NMR and ¹³ C-NMR measurements. Table 1 shows the melting point results of this epoxy resin.
Next, 10 g of this epoxy resin was heated to 130 ° C., 1.22 g of diaminodiphenylmethane (DDM) curing agent was added, and the mixture was stirred and mixed to prepare a uniform resin composition. This resin composition was polymerized by heating in an oven at 150 ° C. for 4 hours to obtain a homogeneous cured resin. When this cured resin was observed using a polarizing microscope, the arrangement of molecular chains in the polymer was confirmed.

(Example 7)
30 g of the epoxy resin represented by the above formula (6), 3.66 g of diaminodiphenylmethane (DDM) curing agent, and 104.34 g of methyl ethyl ketone (MEK) are stirred and mixed, and then boron nitride particles (inorganic A uniform resin composition was prepared by adding 65.79 g of boron nitride particles so that the filler (made by Showa Denko Co., Ltd.) was 50% by volume and sufficiently stirring and mixing. The resin composition was coated on a PET film with a multi coater and dried, and then heated and polymerized at 160 ° C. for 4 hours to obtain a uniform resin cured sheet having a thickness of 100 μm. In addition, this resin composition also had good coating property and moldability to a sheet.

(Comparative Example 1)
A biphenyl type epoxy resin represented by the following formula (7) was synthesized by a known method.

The structure of the epoxy resin was confirmed by infrared spectroscopic analysis and ¹ H-NMR and ¹³ C-NMR measurements. Table 1 shows the melting point results of this epoxy resin.
Next, 10 g of the biphenyl type epoxy resin represented by the above formula (7) was heated to 190 ° C., 3.1 g of diaminodiphenylmethane (DDM) curing agent was added, and the mixture was stirred and mixed to prepare a resin composition. However, since the curing reaction of the epoxy resin proceeded rapidly during preparation, uniform mixing was difficult and a uniform resin composition could not be obtained. Next, this resin composition was polymerized by heating in an oven at 190 ° C. for 4 hours to obtain a cured resin. When this cured resin was observed using a polarizing microscope, the arrangement of molecular chains in the polymer was confirmed. However, this cured resin was heterogeneous.

(Comparative Example 2)
After uniformly stirring and mixing 30 g of the epoxy resin represented by the above formula (7) and 9.3 g of a diaminodiphenylmethane (DDM) curing agent, boron nitride particles (inorganic filler, Showa Denko KK) in the cured resin The resin composition was prepared by adding 74.34 g of boron nitride particles such that the product was 50% by volume, and further adding 117.9 g of methyl ethyl ketone (MEK), followed by thorough mixing. When this resin composition was coated on a PET film with a multicoater and dried, the resin component was peeled off during drying, and a sheet of a cured resin product worthy of evaluation could not be obtained. This result is considered to be due to the fact that the biphenyl type epoxy resin used has high crystallinity and thus has low solubility in a solvent and a high melting point.

About the resin hardened | cured material obtained in Examples 1-7 and Comparative Examples 1-2, and its sheet | seat, the thermal diffusion in the thickness direction using a laser flash method thermal constant measuring apparatus (Rigaku Denki LF / TCM-FA8510B) The rate and specific heat were measured. Moreover, about each resin hardened | cured material and its sheet | seat, the density was measured using the underwater substitution method. Based on these measured values, the thermal conductivity of each cured resin and its sheet was calculated from the following formula.
Thermal conductivity = thermal diffusivity × specific heat × density The results are shown in Table 1.

In Table 1, as can be seen from the comparison between Examples 1 to 6 and Comparative Example 1 (comparison between resin compositions not including an inorganic filler), the cured resin obtained from the resin compositions of Examples 1 to 6 Had higher thermal conductivity than the cured resin obtained from the resin composition of Comparative Example 1.
In the resin compositions of Examples 1 and 2, although the melting point of the compound was high, the solubility of the compound in the solvent was high, so that a uniform resin composition could be obtained. On the other hand, in the resin composition of Comparative Example 1, since the solubility in a solvent was low, it was necessary to prepare a resin composition by heating to a temperature higher than the melting point of the compound. However, as a result of the rapid progress of the curing reaction of the epoxy resin by this high temperature heating, a uniform resin composition could not be obtained.

  Moreover, even if it is a case where an inorganic filler is mix | blended in the resin composition of Example 7, as can be seen from the comparison between Example 7 and Comparative Example 2 (comparison between resin compositions containing an inorganic filler). Since the solubility of the compound in the solvent was high, a uniform resin composition could be obtained. And this resin composition was also excellent in the moldability to a sheet. On the other hand, in the resin composition of Example 2, since the solubility of the compound in the solvent was low, a uniform resin composition could not be obtained. And this resin composition was not sufficient also in the moldability to a sheet | seat.

  As can be seen from the above results, according to the present invention, it is possible to provide a homogeneous resin cured product having high electrical insulation and thermal conductivity and to provide a resin composition excellent in moldability. Moreover, according to this invention, the homogeneous resin hardened | cured material with high electrical insulation and heat conductivity can be provided.

Claims (11)

  A resin composition comprising a compound in which a branched chain having a polymerizable group at an end is bonded to both ends of a main chain, and at least one of the main chain and the branched chain has a mesogenic group.   The mesogenic group is at least one selected from the group consisting of phenyl benzoate, biphenyl, benzophenone, phenyl ether, benzanilide, stilbene, diazobenzene, benzylideneaniline, and derivatives thereof. The resin composition as described.   The terminal polymerizable group in the branched chain is selected from the group consisting of epoxy group, vinyl group, amino group, hydroxyl group, acryloyl group, cyclohexene group, methacryloyl group, cinnamoyl group, isocyanate group and dicarboxylic anhydride group. The resin composition according to claim 1, wherein the resin composition is at least one.   The resin composition according to any one of claims 1 to 3, wherein two or more branched chains are bonded to both ends of the main chain.   5. The resin composition according to claim 1, wherein at least one of the main chain and the branched chain has a flexible group.   The resin composition according to claim 1, wherein the compound is a monomer having a homopolymerizable group as the polymerizable group.   The resin composition according to any one of claims 1 to 5, wherein the compound is an epoxy resin having an epoxy group as the polymerizable group.   The resin composition according to any one of claims 1 to 5, wherein the compound is a curing agent for an epoxy resin having a group capable of reacting with an epoxy group as the polymerizable group.   The resin composition according to any one of claims 1 to 8, further comprising an inorganic filler.   A resin cured product obtained by polymerizing the resin composition according to any one of claims 1 to 9.   The cured resin product according to claim 10, wherein the cured resin product is used as an insulating sheet.