JP2019157022A - Resin composition, resin sheet, laminated substrate and resin cured product - Google Patents

Abstract

To provide a resin composition capable of obtaining a cured product having high heat conductivity.SOLUTION: There is provided a resin composition comprising a thermally conductive filler, a solvent and an organic component other than the solvent, wherein the organic component includes an organic solid matter which has a melting point of 180°C or more and is not dissolved in the solvent and 49 to 65 vol.% of the conductive filler and 4 vol.% or more of the organic solid matter are contained in the resin composition excluding the solvent.SELECTED DRAWING: None

Description

  The present invention relates to a resin composition, a resin sheet, a laminated substrate, and a cured resin product.

  In recent years, the number of electronic devices mounted on automobiles has been increasing. For this reason, downsizing of electronic devices is progressing rapidly. On the other hand, with the miniaturization of electronic devices, the amount of heat generated from the high-density conductors of electronic devices is increasing. For this reason, how to dissipate heat from electronic devices is an important issue.

  Patent Document 1 discloses a prepreg obtained by impregnating a woven fabric base material with a thermosetting resin composition, and contains 80 to 200 parts by volume of an inorganic filler with respect to 100 parts by volume of the thermosetting resin. A prepreg is disclosed.

Japanese Patent No. 5776019

In order to obtain a cured product of a resin composition with good heat dissipation, it is preferable to increase the filler content in the resin composition. However, fillers with high thermal conductivity have a high density. For this reason, when filler content in a resin composition is increased, the weight per unit volume of hardened | cured material will become heavy, and the weight of the electronic device using this will be increased.
For this reason, it is required to increase the thermal conductivity of the cured product without increasing the filler content in the resin composition.

This invention is made | formed in view of the said subject, and makes it a subject to provide the resin composition from which hardened | cured material with high heat conductivity is obtained.
The present invention also provides a resin sheet containing a semi-cured product of the resin composition, a laminated substrate having a high thermal conductivity having a resin substrate containing a cured product of the resin composition, and a heat containing a cured product of the resin composition. It is an object to provide a cured resin having high conductivity.

  In order to solve the above-mentioned problems, the present inventor has focused on the distribution of the heat conductive filler in the curing process of the resin composition, and has made extensive studies. As a result, it has been found that the organic composition other than the solvent may be a resin composition that sufficiently includes an organic solid that does not dissolve in the solvent in the resin composition at a melting point of 180 ° C. or higher and that includes a predetermined amount of the heat conductive filler. It was.

  That is, when the above resin composition is cured, the resin composition is in a solid state from the start of heating of the resin composition until the temperature of the resin composition reaches the melting point of the organic solid. Things exist. At this time, the region where the thermally conductive filler can exist in the resin composition is limited to only a region not occupied by the organic solid. Therefore, in the above resin composition, the volume in which the thermally conductive filler can exist is reduced by the volume of the organic solid, compared to the resin composition that does not include the organic solid and contains the same amount of the thermally conductive filler. . Therefore, while the above resin composition is at a temperature equal to or lower than the melting point of the organic solid, the thermal conductivity is higher in concentration than in the case where the organic solid in the resin composition is not uniformly dispersed, compared with the case where the resin composition is uniformly dispersed. Filler is present.

Then, by further heating, even if the temperature of the resin composition exceeds the melting point of the organic solid and a part or all of the organic solid is melted, the distribution state of the heat conductive filler before the organic solid is melted Is inherited, and a region in which the heat conductive filler is present at a high concentration in the resin composition is formed.
Therefore, the cured product obtained by curing the above resin composition includes, for example, a thermally conductive filler compared to a cured product obtained by curing a resin composition that does not include an organic solid and contains the same amount of a thermally conductive filler. A heat conduction path formed by contact with each other is easily formed. From this, by curing the above resin composition, a cured product having a high thermal conductivity can be obtained as compared with a cured product of a resin composition not containing an organic solid and containing the same amount of a heat conductive filler. It is estimated to be.
The present inventor has conceived the present invention based on such knowledge. That is, the present invention relates to the following inventions.

[1] A resin composition comprising a heat conductive filler, a solvent, and an organic component other than the solvent,
The organic component includes an organic solid that has a melting point of 180 ° C. or higher and does not dissolve in the solvent,
In the resin composition excluding the solvent, the heat conductive filler is contained in 49% by volume to 65% by volume, and the organic solid is contained in 4% by volume or more.

[2] The organic component includes an epoxy compound and a curing agent,
One or both of the epoxy compound and the curing agent contains the organic solid, The resin composition according to [1].
[3] The resin composition as described in [2], wherein the curing agent includes a compound containing a phosphorus atom.
[4] The resin composition as described in [3], wherein the curing agent includes any one or more selected from compounds represented by the following formulas (1) to (3).

[5] A resin sheet comprising a semi-cured product of the resin composition according to any one of [1] to [4].
[6] A laminated substrate in which one or a plurality of resin sheets are laminated,
A laminated substrate, wherein one or two or more of the one or more resin sheets contain a cured product of the resin composition according to any one of [1] to [4].
[7] A cured resin containing a cured product of the resin composition according to any one of [1] to [4].

  According to the resin composition of the present invention, by curing this, a cured product having a high thermal conductivity is obtained compared to a cured product of a resin composition that does not contain an organic solid and contains the same amount of a heat conductive filler. can get. Moreover, according to the resin composition of the present invention, compared with the case where the heat conductivity of the cured product is improved by increasing the heat conductive filler without containing organic solids, the weight is less cured per unit volume. A thing is obtained.

The resin sheet of the present invention is a semi-cured product of the resin composition of the present invention. For this reason, for example, by laminating one or a plurality of the resin sheets of the present invention and heating and pressing, a multilayer substrate having a high thermal conductivity containing a cured product of the resin composition can be obtained.
The laminated substrate of the present invention has a high thermal conductivity because one or two or more of the plurality of resin sheets contain a cured product of the resin composition of the present invention.
Since the cured resin of the present invention includes the cured product of the resin composition of the present invention, it has a high thermal conductivity.

It is the perspective view which showed an example of the resin sheet of this embodiment. It is the II sectional view taken on the line of FIG. It is sectional drawing which showed an example of the resin cured material of this embodiment. It is sectional drawing which showed an example of the laminated substrate of this embodiment.

  Hereinafter, the resin composition, the resin sheet, the laminated substrate, and the cured resin (sometimes abbreviated as “cured product”) of the present invention will be described in detail with reference to the drawings. In the drawings used in the following description, in order to make the characteristics of the present invention easier to understand, there are cases where the characteristic parts are enlarged for convenience. Therefore, the dimensional ratios of the components described in the drawings may be different from actual ones. The materials, dimensions, and the like exemplified in the following description are merely examples, and the present invention is not limited thereto, and can be implemented with appropriate modifications within a range that does not change the gist thereof.

[Resin composition]
The resin composition of this embodiment contains a heat conductive filler, a solvent, and organic components other than the solvent.
(Organic component)
The organic component is an organic compound other than the solvent contained in the resin composition. The organic component is preferably contained in the resin composition excluding the solvent in an amount of 30 to 70% by volume, and more preferably in an amount of 35 to 51% by volume. If the organic component is contained in an amount of 30% by volume or more in the resin composition excluding the solvent, it is preferable because good moldability can be obtained. When the organic component is contained in the resin composition excluding the solvent in an amount of 70% by volume or less, the content of the heat conductive filler is easily secured, and a cured product having high heat conductivity is easily obtained, which is preferable.

  The organic component includes an organic solid. The organic solid has a melting point of 180 ° C. or higher and does not dissolve in the solvent in the resin composition. Therefore, even when the resin composition is heated to a temperature of less than 180 ° C., the organic solid in the resin composition does not melt and can maintain a solid state. The heating temperature for semi-curing the resin composition is usually less than 180 ° C. For this reason, the organic solid is not melted even if normal heating for semi-curing the resin composition is performed, and is present in the resin composition while maintaining the solid state. Moreover, the heating temperature for hardening a resin composition may be 180 degreeC or more. Therefore, a part or all of the organic solid material may be melted by heating for curing the resin composition.

  The melting point of the organic solid is preferably 210 ° C. or higher. When the melting point of the organic solid is 210 ° C. or higher, the time until the temperature of the resin composition reaches the melting point of the organic solid becomes longer after the heating for curing the resin composition is started. Even if the heating for curing the product is performed, the temperature of the resin composition does not reach the melting point of the organic solid. As a result, a region where the heat conductive filler is present at a high concentration is more easily formed, and a cured product having higher heat conductivity is easily obtained, which is preferable.

  The melting point of the organic solid is preferably 300 ° C. or lower. The heating temperature for curing the resin composition is usually 300 ° C. or lower. When the melting point of the organic solid is 300 ° C. or lower, the organic solid can be melted by normal heating for curing the resin composition. Therefore, for example, a compound that melts at the time of curing such as an epoxy compound and / or a curing agent and contributes to the formation of a cured product can be used as the organic solid, which is preferable.

  In the present embodiment, 4% by volume or more of organic solids is contained in the resin composition excluding the solvent. For this reason, when the resin composition is cured, a region where the heat conductive filler is present at a high concentration is sufficiently formed, and compared with a cured product of the resin composition containing the same amount of the heat conductive filler without containing an organic solid. Thus, a cured product having high thermal conductivity can be obtained. The organic solid is preferably contained in an amount of 10% by volume or less in the resin composition excluding the solvent because the fluidity at the time of curing the resin composition can be secured and good moldability can be obtained.

  As the organic solid material, it is preferable to use one having a volume-based average particle diameter of 0.1 to 100 μm measured by a commercially available laser diffraction particle size distribution analyzer, and one having 1 to 50 μm is used. More preferred. When the average particle diameter of the organic solid is 0.1 μm or more, a region where the heat conductive filler exists at a high concentration is more easily formed when the resin composition is cured, which is preferable. Moreover, it is preferable that the average particle size of the organic solid is 100 μm or less because the moldability of the resin composition is good, and a cured product having a small thickness and a cured product having a uniform thickness can be easily formed. The particle size distribution of the organic solid substance measured by the measuring device may have a plurality of peaks.

  The organic component may contain an epoxy compound and a curing agent, or only an epoxy compound and a curing agent. When the organic component contains an epoxy compound and a curing agent, either one or both of the epoxy compound and the curing agent may contain an organic solid.

(Epoxy compound)
The epoxy compound is polymerized by a curing agent to form a semi-cured product and a resin cured product together with the curing agent. Examples of the epoxy compound include bisphenol A type, bisphenol F type, glycidyl ether type, glycidyl ester type, and glycidyl amine type. As the epoxy compound, one of them may be used alone, or a plurality of them may be used in combination.
The epoxy equivalent of the epoxy compound may be, for example, 100 to 1000 g / eq.

  It is preferable to use an epoxy compound having a mesogen skeleton. Examples of the epoxy compound having a mesogen skeleton include those having two or more benzene rings in one molecule such as a biphenyl skeleton and a terphenyl skeleton. By using an epoxy compound having a mesogenic skeleton as the epoxy compound, a resin composition is obtained in which a cured product having high thermal conductivity and good heat dissipation is obtained.

As the epoxy compound having a mesogen skeleton, glycidyl ethers having a biphenyl skeleton and two or more epoxy groups in one molecule can be used. Examples of glycidyl ethers include biphenyl glycidyl ether and tetramethylbiphenyl glycidyl ether.
As the epoxy compound having a mesogen skeleton, glycidyl ethers having a terphenyl skeleton in one molecule may be used.

  As the epoxy compound, a phosphorus-containing epoxy compound containing a phosphorus atom may be used. By using a phosphorus containing epoxy compound as an epoxy compound, it becomes the resin composition from which hardened | cured material with favorable flame retardance is obtained.

  An epoxy compound having a melting point of 180 ° C. or higher may be used. Examples of such an epoxy compound include 4,4 ′ ″-hydroxy 2-methylterphenyl type epoxy. An epoxy compound having a melting point of 180 ° C. or higher can be used as an organic solid by using a solvent that does not dissolve it as a solvent.

(Curing agent)
As the curing agent, one type of known curing agents may be used alone, or a plurality of types may be used in combination.
The curing agent preferably contains a compound containing a phosphorus atom. When a hardening | curing agent contains the compound containing a phosphorus atom, it becomes a resin composition from which the hardened | cured material with favorable flame retardance is obtained.

  Specifically, as the curing agent, 10- [2- (dihydroxynaphthyl)]-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide represented by the following formula (1), 10- (2,5-dihydroxyphenyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide represented by the formula (2), 2- (diphenylphosphine represented by the following formula (3) Phinyl) hydroquinone, 4,4′-biphenol represented by the following formula (4), phenol having a phenolic hydroxyl group such as 1.3.5-tris (4-hydroxyphenyl) benzene represented by the following formula (5) , Amine curing agents, acid anhydride curing agents, dicyandiamide, imidazole, and the like can be used.

  A curing agent having a melting point of 180 ° C. or higher may be used. Examples of such a curing agent include compounds represented by the above formulas (1) to (5), dicyandiamide, and the like. Among these curing agents, it is particularly preferable to use one or more selected from compounds represented by formulas (1) to (3) which are compounds containing phosphorus atoms. A curing agent having a melting point of 180 ° C. or higher can be used as an organic solid by using a solvent that does not dissolve it as a solvent.

(Thermal conductive filler)
The resin composition of this embodiment contains a heat conductive filler. By including a heat conductive filler, a cured product having high heat conductivity can be obtained.
Examples of the heat conductive filler include boron nitride particles, magnesium oxide particles, alumina particles, aluminum hydroxide particles, aluminum nitride particles, and silica particles. As the heat conductive filler, one of these may be used alone, or a plurality of may be used in combination.

  The heat conductive filler is contained in the resin composition excluding the solvent in an amount of 49 volume% to 65 volume%, preferably 49 volume% to 60 volume%. When the heat conductive filler is contained in the resin composition excluding the solvent in an amount of 49% by volume or more, the heat conductive fillers are easily brought into contact with each other, so that a cured product having high heat conductivity is obtained. When the heat conductive filler is contained in the resin composition excluding the solvent in an amount of 65% by volume or less, the flowability of the resin composition is hardly impaired by the heat conductive filler when molding a cured product of the resin composition. Good formability.

  As the heat conductive filler, it is preferable to use those having a volume-based average particle diameter of 1 to 100 μm, more preferably 1 to 30 μm, as measured by a commercially available laser diffraction particle size distribution analyzer. . The particle size distribution of the heat conductive filler measured by the measuring device may have a plurality of peaks.

(solvent)
As the solvent, a solvent that does not dissolve an organic component having a melting point of 180 ° C. or higher used as an organic solid is used, and can be appropriately selected according to the type of the compound used as the organic solid.
For example, when a 4,4 ″ -hydroxy 2-methylterphenyl type epoxy, which is an epoxy compound, is used as the organic solid material, alcohol, ketone, ethers, or the like can be used as the solvent.
Moreover, alcohol, a ketone, ethers, etc. can be used as a solvent, when using any of the compounds shown by said formula (1)-(4) which is a hardening | curing agent as an organic solid substance.

  The resin composition of this embodiment may contain arbitrary components as needed in addition to the epoxy compound, the curing agent, the filler, and the solvent. Optional components include curing accelerators (curing catalysts) such as phosphines and imidazoles (such as 2-ethyl-4-methylimidazole), coupling agents such as silane coupling agents and titanate coupling agents, and difficulties such as halogens. Examples include a flame retardant, a plasticizer, and a lubricant.

  The resin composition of the present embodiment can be produced by, for example, a method of mixing a heat conductive filler, a solvent, an organic component other than the solvent, and an optional component contained as necessary.

The resin composition of the present embodiment includes a heat conductive filler, a solvent, and an organic component other than the solvent, and the organic component includes an organic solid that has a melting point of 180 ° C. or higher and does not dissolve in the solvent in the resin composition, The resin composition excluding the solvent contains 49% to 65% by volume of the heat conductive filler and 4% by volume or more of the organic solid. For this reason, by curing the resin composition of the present embodiment, a cured product having a high thermal conductivity is obtained as compared with a cured product of a resin composition that does not contain an organic solid and contains the same amount of a heat conductive filler. It is done.
Moreover, the organic solid has a lower density than the heat conductive filler. Therefore, according to the resin composition of the present embodiment, the weight per unit volume is small as compared with the case where the thermal conductivity of the cured product is improved by increasing the thermal conductive filler without containing organic solids. A cured product is obtained.

[Resin sheet]
FIG. 1 is a perspective view showing a prepreg as an example of a resin sheet of the present embodiment. 2 is a cross-sectional view taken along the line II of FIG. FIG. 2 shows a cross section when the prepreg shown in FIG. 1 is cut along the thickness direction.

The prepreg 12 shown in FIG. 2 is a resin sheet including a fibrous core material 30 and a resin component 22 in a semi-cured state (B stage state) impregnated in the core material 30. The resin component 22 of the prepreg 12 shown in FIG. 2 is a semi-cured product of the resin composition of the above-described embodiment.
Examples of the core material 30 include woven fabric and non-woven fabric. Examples of the material for the woven fabric and the non-woven fabric include one type or two or more types of fibers selected from glass fibers, carbon fibers, metal fibers, natural fibers, polyester fibers, polyamide fibers, and other synthetic fibers. However, the core material 30 is not limited to these. A resin sheet that does not include the core material 30 may be used.

The prepreg 12 shown in FIG. 2 can be manufactured by the method shown below, for example.
After impregnating the core material 30 with a technique such as applying or immersing the resin composition, the core material 30 impregnated with the resin composition is heated. By this heating, the resin composition is semi-cured to obtain the prepreg 12 including the resin component 22.
The heating conditions for semi-curing the resin composition can be, for example, 60 to 150 ° C. for about 1 to 120 minutes, and 70 to 120 ° C. for about 3 to 90 minutes.

  In the present embodiment, the resin composition contains an organic solid that has a melting point of 180 ° C. or higher and does not dissolve in the solvent in the resin composition. The organic solid does not melt even when heating for semi-curing the resin composition, and exists in the resin component 22 of the prepreg 12 while maintaining the solid state.

In the prepreg 12 shown in FIG. 2, the semi-cured resin component 22 impregnated in the core material 30 is a semi-cured product of the resin composition of the above-described embodiment. For this reason, solid organic solids are present in the resin component 22, and the thermal conductivity is higher than that in the case where the organic solids in the resin component 22 are not uniformly dispersed in the region. Filler is present.
Therefore, for example, by laminating a plurality of prepregs 12 shown in FIG. 2 and applying heat and pressure, a heat conduction path formed by contacting the heat conductive fillers is easily formed, and the heat conductivity including a cured product of the resin composition. A highly laminated substrate can be obtained.

[Resin cured product]
FIG. 3 is a cross-sectional view showing an example of the cured resin product of the present embodiment. A cured resin product 20 shown in FIG. 3 is a cured resin sheet 50 made of a cured product of the resin composition of the above-described embodiment.
The cured resin sheet 50 is formed, for example, by applying the resin composition onto a release film made of polyethylene terephthalate (PET) or the like to form a coating film, and heating the resin composition to cure the resin composition. 20 can be produced.
The heating conditions for curing the resin composition are, for example, about 100 to 250 ° C. and about 1 to 300 minutes.

In the present embodiment, the resin composition contains an organic solid that has a melting point of 180 ° C. or higher and does not dissolve in the solvent in the resin composition. The organic solid does not dissolve when the heating temperature for curing the resin composition is equal to or lower than the melting point, and exists in the cured resin 20 while maintaining a solid state. Therefore, in the area | region which the organic solid of resin cured | curing material 20 does not occupy, the area | region where a thermally conductive filler exists in a higher density | concentration than the case where it disperse | distributes uniformly is formed.
Moreover, when the heating temperature for hardening a resin composition exceeds melting | fusing point, a part or all of organic solid substance fuse | melts by the heating for forming hardened | cured material. However, since the distribution state of the heat conductive filler before the organic solid is melted is inherited in the cured resin 20, a region where the heat conductive filler is present at a higher concentration than when uniformly dispersed is formed.
From this, the cured resin sheet of the present embodiment, which is a cured product of the resin composition of the present embodiment, has a high thermal conductivity.

[Laminated substrate]
FIG. 4 is a cross-sectional view showing an example of the multilayer substrate of the present embodiment. A laminated substrate 41 shown in FIG. 4 includes two laminated fiber reinforced resin sheets (resin substrates) 42 and 42 and a metal foil 40 disposed in contact with one of the fiber reinforced resin sheets 42. The fiber reinforced resin sheets 42 and 42 each have a resin layer 20 containing a cured product of the resin composition of the above-described embodiment, and a fibrous core material 30 disposed in the resin layer 20.

As the metal foil 40, a known one can be appropriately selected and used. Specifically, as the metal foil 40, for example, a copper foil, a nickel foil, an aluminum foil, or the like can be used. The thickness of the metal foil 40 is not specifically limited, For example, it is about 3-150 micrometers. The metal foil 40 may be etched and / or punched.
As the core material 30, the same material as the core material 30 that can be used for the prepreg 12 shown in FIG. 2 can be used.

The laminated substrate 41 shown in FIG. 4 can be manufactured by the method shown below, for example.
Two prepregs 12 shown in FIG. 2 are stacked, and a metal foil 40 is stacked thereon and heated. By this heating, the resin component 22 is cured to become the resin layer 20 and the laminated substrate 41 in which the two fiber reinforced resin sheets 42 and 42 and the metal foil 40 are integrated. Subsequently, the metal foil 40 may be etched and / or punched.
The heating conditions for curing the resin component 22 that is a semi-cured product are, for example, about 100 to 250 ° C. and about 1 to 300 minutes.
When heating the prepreg 12 having the metal foil 40 laminated on the surface, it may be pressurized. The pressurizing condition can be, for example, about 0.1 to 10 MPa.

  The laminated substrate 41 of this embodiment is obtained by laminating two fiber reinforced resin sheets 42 and 42 and a metal foil 40. The fiber reinforced resin sheets 42 and 42 are made of the resin composition of the above-described embodiment. Includes cured products. For this reason, the laminated substrate 41 of this embodiment has a high thermal conductivity.

As mentioned above, although several embodiment of this invention was described, this invention is not limited to the said embodiment at all.
For example, in the above-described embodiment, the laminated substrate 41 is an example having two laminated fiber reinforced resin sheets 42 and 42 and a metal foil 40 arranged in contact with one fiber reinforced resin sheet 42. As described above, the metal foil 40 may be disposed on both surfaces of the two laminated fiber reinforced resin sheets 42, 42, or the metal foil may not be provided.

In the laminated substrate, one or more of the plurality of resin substrates (in the example shown in FIG. 4, fiber reinforced resin sheets 42 and 42) includes a cured product of the resin composition of the present invention. For example, a plurality of cured resin sheets 50 shown in FIG. 3 may be laminated.
For example, in the above-described embodiment, the resin cured product sheet 50 formed into a sheet shape has been described as an example of the resin cured product 20, but the resin cured product has an amorphous resin composition such as an adhesive, for example. It may be a cured product.

  Hereinafter, the contents of the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

(Examples 1-10, Comparative Examples 1-12)
The following epoxy compounds, curing agents, curing catalysts, thermally conductive fillers and solvents are mixed, and the viscosity is set to about 1000 cps by adjusting the amount of the solvent added. The resins of Examples 1 to 10 and Comparative Examples 1 to 12 A composition was prepared.
In Examples 1 to 10 and Comparative Examples 1 to 12, organic components other than the solvent are an epoxy compound, a curing agent, and a curing catalyst. Tables 1 and 2 show the contents of the epoxy compound, the curing agent, and the curing catalyst (volume ratio (volume%) in the resin composition excluding the solvent).

The component ratio of the organic solid and the component ratio of the heat conductive filler shown in Table 1 and Table 2 are volume ratios (volume%) in the resin composition excluding the solvent.
Moreover, the epoxy compound C and the curing agents b to e in Tables 1 and 2 are organic solids having a melting point of 180 ° C. or higher and not dissolved in the solvent in the resin composition. The curing agent a is an organic compound having a melting point of 180 ° C. or higher, but is not an organic solid because it is dissolved in the solvent in the resin composition.

(Epoxy compound)
Epoxy compound A: a bisphenol F type liquid epoxy resin. (Product name: 830-S, manufactured by DIC Corporation)
Epoxy compound B: about 1: 1 mixture of tetramethylbiphenol type epoxy resin and 4,4′-biphenol type epoxy resin. (Product name: YL-6121H, manufactured by Mitsubishi Chemical Corporation)
Epoxy compound C: 4,4 ″ -hydroxy 2-methylterphenyl type epoxy (melting point: 180 ° C., average particle size: 30 μm, specific gravity: 1.16)

(Curing agent)
Curing agent a: Compound represented by the following formula (5) (melting point: 229 ° C., specific gravity: 1.27)
Curing agent b: Compound represented by the following formula (3) (melting point: 215 ° C., average particle diameter (median diameter (d50)): 10 μm, specific gravity: 1.40)
Curing agent c: compound represented by the following formula (1) (melting point: 250 ° C., average particle size (d50): 2 μm, specific gravity: 1.40)
Curing agent d: Compound represented by the following formula (2) (melting point: 250 ° C., average particle diameter (d50): 46 μm, specific gravity: 1.40)
Curing agent e: compound represented by the following formula (4) (melting point: 280 ° C., average particle size (d50): 31 μm, specific gravity: 1.22)

(Curing catalyst)
2-Ethyl-4-methylimidazole (2E4MZ) (liquid at room temperature, soluble in methyl ethyl ketone used as solvent)
(Thermal conductive filler)
Magnesium oxide particles (average particle size (d50): 20 μm)
(solvent)
Methyl ethyl ketone

Next, each of the resin compositions of Examples 1 to 10 and Comparative Examples 1 to 12 was impregnated into a core material made of a glass fiber woven fabric having a thickness of 0.05 mm and a fabric weight of 47 g / m ² , and at 80 ° C. The resin composition was semi-cured by heating for 10 minutes to obtain a resin sheet having a cloth weight of 350 g / m ² .
Six sheets of the obtained resin sheets were laminated, heated from 40 ° C. to 220 ° C. over 60 minutes at a pressure of 3 MPa, held at 220 ° C. for about 1 hour to cure the resin composition, and then cooled, And a laminated substrate having a thickness of about 1 mm was obtained.
With respect to the laminated substrates of Examples 1 to 10 and Comparative Examples 1 to 12 thus obtained, “thermal conductivity”, “change rate”, and “moldability” were examined by the following method. The results are shown in Tables 1 and 2.

"Thermal conductivity"
The produced laminated substrates of each Example and each Comparative Example having a thickness of about 1 mm were cut into a disk shape having a diameter of 10 mm to produce test pieces. The thermal diffusion coefficient α [m ² / s] of the test piece was measured using a laser flash method thermal conductivity measuring device (manufactured by ULVAC-RIKO, Inc., device name: TC-7000). The specific heat Cp [J / (kg · K)] of the test piece was measured by differential thermal analysis (DSC). At this time, measurement was performed using sapphire as a standard sample. The density r (kg / m ³ ) of the test piece was measured by the Archimedes method. Using these measured values, the thermal conductivity λ [W / (m · K)] was calculated by the following formula.
λ = α × Cp × r

"Rate of change"
The amount of increase in the “thermal conductivity” of each example relative to the “thermal conductivity” of the comparative example in which the component ratio of the epoxy compound and the thermal conductive filler is the same and does not include organic solids is calculated by the following formula, It was. For Example 10, the amount of increase in “thermal conductivity” relative to “thermal conductivity” in Comparative Example 10 was calculated.
Rate of change (%) = {(thermal conductivity / thermal conductivity of comparative example with the same epoxy compound and no organic solid) × 100} −100

"Formability"
A 20 mm × 20 mm square test piece was cut out from the laminated substrates of each Example and Comparative Example having a thickness of about 1 mm, and the cross section was polished with # 300 sandpaper. The surface and cross section of the test piece were observed at a magnification of 10 times using an optical microscope, the presence or absence of voids on the surface and the cut surface was confirmed, and evaluated according to the following criteria.
A: No void was formed on the surface and cross section of the test piece.
X: A void was formed on the surface and / or cross section of the test piece.

As shown in Table 1 and Table 2, in Examples 1 to 10 that sufficiently contain organic solids and include a predetermined amount of heat conductive filler, the rate of change is 5.0% or more, and no organic solids are contained. Compared with the cured product of the comparative example containing the same amount of conductive filler, a cured product having high thermal conductivity was obtained.
On the other hand, in Comparative Examples 1 and 6, which sufficiently contained organic solids but lacked the heat conductive filler, the effect of improving the heat conductivity was not obtained (rate of change 0%). Moreover, in the comparative example 12 which contains a heat conductive filler excessively, moldability evaluation was "x".
Further, in Comparative Example 11 in which a predetermined amount of the heat conductive filler was included but the organic solid was insufficient, the effect of improving the heat conductivity was not obtained (change rate 0%).

  DESCRIPTION OF SYMBOLS 12 ... Prepreg, 20 ... Resin layer, 22 ... Resin component, 30 ... Core material, 40 ... Metal foil, 41 ... Laminated substrate, 42 ... Fiber reinforced resin sheet, 50 ... Resin hardened material sheet.

Claims (7)

A heat conductive filler, a solvent, and a resin composition containing an organic component other than the solvent,
The organic component includes an organic solid that has a melting point of 180 ° C. or higher and does not dissolve in the solvent,
In the resin composition excluding the solvent, the heat conductive filler is contained in 49% by volume to 65% by volume, and the organic solid is contained in 4% by volume or more. The organic component includes an epoxy compound and a curing agent,
2. The resin composition according to claim 1, wherein one or both of the epoxy compound and the curing agent includes the organic solid.   The resin composition according to claim 2, wherein the curing agent contains a compound containing a phosphorus atom. The resin composition according to claim 3, wherein the curing agent contains one or more selected from compounds represented by the following formulas (1) to (3).

  A resin sheet comprising a semi-cured product of the resin composition according to any one of claims 1 to 4. A laminated substrate in which one or a plurality of resin sheets are laminated,
Lamination | stacking characterized by the 1 or 2 or more resin sheet of the said 1 sheet or several sheets of resin sheet containing the hardened | cured material of the resin composition as described in any one of Claims 1-4. substrate.   Hardened resin containing the hardened | cured material of the resin composition as described in any one of Claims 1-4.

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