JPWO2018139639A1 - Resin material and laminate - Google Patents

Abstract

Disclosed is a resin material that can effectively improve insulation and thermal conductivity, can effectively suppress variations in dielectric breakdown strength, and can effectively improve adhesiveness. The resin material according to the present invention includes first inorganic particles, second inorganic particles, and a binder resin, and the primary particles constituting the first inorganic particles have an aspect ratio of 7 or more, The aspect ratio of the primary particles constituting the inorganic particles of 2 is less than 7, the compressive strength of the first inorganic particles at 10% compression, and the compressive strength of the second inorganic particles at 10% compression. Are 2 N / mm 2 or less.

Description

  The present invention relates to a resin material containing inorganic particles and a binder resin. Moreover, this invention relates to the laminated body using the said resin material.

  In recent years, downsizing and higher performance of electronic and electrical devices have progressed, and the mounting density of electronic components has increased. For this reason, it is a problem how to dissipate the heat generated from the electronic components in a narrow space. Since heat generated from electronic components is directly linked to the reliability of electronic and electrical equipment, efficient dissipation of the generated heat is an urgent issue.

  As one means for solving the above-mentioned problem, there is a means that uses a ceramic substrate having high thermal conductivity as a heat dissipation substrate for mounting a power semiconductor device or the like. Examples of such a ceramic substrate include an alumina substrate and an aluminum nitride substrate.

  However, the means using the ceramic substrate has a problem that it is difficult to make a multilayer, workability is poor, and cost is very high. Furthermore, since the difference in coefficient of linear expansion between the ceramic substrate and the copper circuit is large, there is also a problem that the copper circuit is easily peeled off during the cooling and heating cycle.

  Therefore, a resin composition using boron nitride having a low linear expansion coefficient, particularly hexagonal boron nitride, has attracted attention as a heat dissipation material. The crystal structure of hexagonal boron nitride is a layered structure of hexagonal network similar to graphite, and the particle shape of hexagonal boron nitride is scaly. For this reason, it is known that hexagonal boron nitride has a property in which the thermal conductivity in the plane direction is higher than the thermal conductivity in the thickness direction and the thermal conductivity is anisotropic.

  Secondary agglomerated particles (boron nitride agglomerated particles) in which the primary particles of hexagonal boron nitride are agglomerated as a method of reducing the thermal conductivity anisotropy of hexagonal boron nitride and improving the thermal conductivity in the thickness direction. It has been proposed to use The following Patent Documents 1 to 3 disclose resin compositions using boron nitride aggregated particles.

  Patent Document 1 below discloses a thermosetting resin composition containing an inorganic filler in a thermosetting resin. The inorganic filler includes a secondary aggregate (A) composed of primary particles of boron nitride having an average major axis of 8 μm or less, and a secondary aggregate composed of primary particles of boron nitride having an average major axis of more than 8 μm and 20 μm or less. The next aggregate (B) is contained in a volume ratio of 40:60 to 98: 2. Content of the said inorganic filler is 40 volume% or more and 80 volume% or less.

  The following Patent Document 2 discloses a curable heat radiation composition comprising two types of fillers having different compressive fracture strengths (except that the above two types of fillers are the same substance) and a curable resin (C). Things are disclosed. The compression fracture strength ratio (compression fracture strength of filler (A) having a high compression fracture strength / compression fracture strength of filler (B) having a small compression fracture strength) of the two kinds of fillers is 5 or more and 1500 or less. The filler (B) is hexagonal boron nitride aggregate particles.

  Patent Document 3 below discloses a thermosetting resin composition containing a thermosetting resin and an inorganic filler. The inorganic filler is formed of secondary particles (A) formed from primary particles of boron nitride having an aspect ratio of 10 or more and 20 or less, and primary particles of boron nitride having an aspect ratio of 2 or more and 9 or less. Secondary particles (B).

JP2011-6586A WO2013 / 1455961A1 WO2014 / 199650A1

  In the curable composition using the conventional boron nitride aggregated particles as described in Patent Documents 1 to 3, in order to maintain the isotropic thermal conductivity of the boron nitride aggregated particles, during pressing such as sheet molding, It is necessary not to collapse the boron nitride aggregated particles by pressing. For this reason, voids may remain between boron nitride aggregated particles. As a result, although the thermal conductivity in the thickness direction can be improved, the insulating property may be lowered.

  Further, when pressing such as sheet forming to eliminate voids between the boron nitride aggregated particles, the boron nitride aggregated particles are deformed or collapsed, and the thermal conductivity isotropic property of the boron nitride aggregated particles may be lost. is there. As a result, the thermal conductivity in the pressing direction (thickness direction) may decrease. A curable composition using conventional boron nitride aggregated particles has a limit in achieving both high insulation and high thermal conductivity.

  Moreover, in the curable composition using the conventional boron nitride aggregated particles, it is difficult to uniformly compress the boron nitride aggregated particles having different compressive strengths, and the dielectric breakdown strength may vary.

  Moreover, in the curable composition using the conventional boron nitride aggregated particles, voids are likely to be formed between the boron nitride aggregated particles, and the adhesion may be reduced due to the formation of voids in the vicinity of the adherend. .

  An object of the present invention is to provide a resin that can effectively improve insulation and thermal conductivity, can effectively suppress variations in dielectric breakdown strength, and can effectively improve adhesion. Is to provide materials. Moreover, the objective of this invention is providing the laminated body using the said resin material.

According to a wide aspect of the present invention, the aspect ratio of primary particles comprising the first inorganic particles, the second inorganic particles, and the binder resin, and constituting the first inorganic particles is 7 or more, The aspect ratio of the primary particles constituting the second inorganic particles is less than 7, the compression strength of the first inorganic particles at 10% compression, and the compression of the second inorganic particles at 10% compression A resin material having a strength of ² N / mm ² or less is provided.

  On the specific situation with the resin material which concerns on this invention, the particle diameter of a said 2nd inorganic particle is 10 micrometers or more and 50 micrometers or less.

In a specific aspect of the resin material according to the present invention, the compressive strength at the time of 10% compression of the second inorganic particles is 1.5 N / mm ² or less, and 20% of the first inorganic particles. The compression strength at the time of compression and the compression strength at the time of 20% compression of the second inorganic particles are each 3N / mm ² or less, and the compression strength at the time of compression of 30% of the first inorganic particles The compressive strength at 30% compression of the second inorganic particles is 4 N / mm ² or less, respectively.

In a specific aspect of the resin material according to the present invention, the absolute difference between the compressive strength at the time of 20% compression of the first inorganic particles and the compressive strength at the time of 20% compression of the second inorganic particles. The value is 1.5 N / mm ² or less, and the compression strength at the time of 30% compression of the first inorganic particles is the same as or smaller than the compression strength at the time of 30% compression of the second inorganic particles. .

  On the specific situation with the resin material which concerns on this invention, a said 1st inorganic particle and a said 2nd inorganic particle are boron nitride aggregated particles, respectively.

  In a specific aspect of the resin material according to the present invention, the total content of the first inorganic particles and the second inorganic particles in 100% by volume of the resin material is 20% by volume or more and 80% by volume or less. It is.

  On the specific situation with the resin material which concerns on this invention, the said resin material is a resin sheet.

  According to a wide aspect of the present invention, a heat conductor, an insulating layer laminated on one surface of the heat conductor, and a conductive layer laminated on the surface of the insulating layer opposite to the heat conductor. A laminate is provided in which the material of the insulating layer is the resin material described above.

The resin material according to the present invention includes first inorganic particles, second inorganic particles, and a binder resin. In the resin material according to the present invention, the aspect ratio of the primary particles constituting the first inorganic particles is 7 or more, and the aspect ratio of the primary particles constituting the second inorganic particles is less than 7. In the resin material according to the present invention, the compressive strength at the time of 10% compression of the first inorganic particles and the compressive strength at the time of 10% compression of the second inorganic particles are each 2N / mm ² or less. is there. In the resin material according to the present invention, since the above-described configuration is provided, it is possible to effectively increase the insulation and the thermal conductivity, to effectively suppress the variation in the dielectric breakdown strength, , The adhesiveness can be effectively increased.

FIG. 1 is a cross-sectional view schematically showing a resin sheet according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a laminate obtained using the resin material according to one embodiment of the present invention.

  Hereinafter, the present invention will be described in detail.

(Resin material)
The resin material according to the present invention includes first inorganic particles, second inorganic particles, and a binder resin.

  In the resin material according to the present invention, the aspect ratio of the primary particles constituting the first inorganic particles is 7 or more, and the aspect ratio of the primary particles constituting the second inorganic particles is less than 7.

In the resin material according to the present invention, the compressive strength at the time of 10% compression of the first inorganic particles and the compressive strength at the time of 10% compression of the second inorganic particles are each 2N / mm ² or less. is there.

  In the resin material according to the present invention, since the above-described configuration is provided, it is possible to effectively increase the insulation and the thermal conductivity, to effectively suppress the variation in the dielectric breakdown strength, Adhesiveness can be effectively increased.

  In the resin material according to the present invention, two types of inorganic particles are used, and the aspect ratios of the primary particles constituting the two types of inorganic particles are different. For example, boron nitride particles and the like are known as inorganic particles having high thermal conductivity. When a resin material containing only fragile inorganic particles composed of primary particles having a relatively small aspect ratio is pressed by sheet molding or the like, the inorganic particles are deformed or collapsed by the press, and the inorganic particles are oriented in the plane direction. To do. When the inorganic particles are oriented in the plane direction, the thermal conductivity in the plane direction can be increased, but the thermal conductivity in the thickness direction (press direction) cannot be increased. When a resin material containing only hard inorganic particles composed of primary particles having a relatively large aspect ratio is used and pressed by sheet molding or the like, the inorganic particles are hardly deformed or collapsed by the press, and the surface direction and the thickness direction However, the voids remain between the inorganic particles, and the insulating properties deteriorate.

  When a compressive force is applied to the resin material according to the present invention by a press or the like, the first inorganic particles and the second inorganic particles are deformed or collapsed. Since the aspect ratio of the primary particles constituting the first inorganic particles is relatively large, the first inorganic particles are deformed due to the entanglement of the primary particles compared to the second inorganic particles, It does not collapse excessively and is easy to maintain the particle shape. On the other hand, since the aspect ratio of the primary particles constituting the second inorganic particles is relatively small, the second inorganic particles cannot maintain the particle shape and are moderate around the first inorganic particles. Deforms or collapses. For this reason, the voids existing between the first inorganic particles can be filled with the deformed or collapsed second inorganic particles, and the insulation can be effectively enhanced. In addition, the first inorganic particles can be deformed according to the shape of the second inorganic particles that are appropriately deformed or collapsed. In that case, since the space | gap between particle | grains can be filled with the binder resin which exists in the said 1st inorganic particle, insulation can be improved effectively.

  Furthermore, the second inorganic particles can be oriented between the first inorganic particles when deforming or collapsing, and the thermal conductivity can be effectively increased. Further, the deformed or collapsed second inorganic particles can prevent the first inorganic particles from being completely compressed in the surface direction. Therefore, the thermal conductivity in the thickness direction can be effectively increased.

  In the resin material according to the present invention, the first inorganic particles and the second inorganic particles having a specific compressive strength are used. When pressing is performed by sheet molding or the like using the resin material according to the present invention, the first inorganic particles and the second inorganic particles are compressed relatively uniformly and deformed together by the press. It is possible to further reduce the voids existing in. For this reason, the partial discharge (internal discharge) by the space | gap inside a sheet | seat can be prevented, and the dispersion | variation in dielectric breakdown strength can be suppressed effectively.

  In the resin material according to the present invention, the first inorganic particles can hold the binder resin inside the particles. Therefore, when the first inorganic particles are deformed by a press or the like, the binder resin is used to form a space between the particles. A space | gap can be filled and formation of a space | gap can be suppressed effectively. Furthermore, since the formation of voids in the vicinity of the adherend can be effectively suppressed, the adhesion with the adherend can be effectively increased. Further, since the aspect ratio of the primary particles constituting the second inorganic particles is relatively small, and there are relatively many functional groups in the short side direction of the primary particles constituting the second inorganic particles, the adhesiveness Can be effectively increased.

  In order to obtain such an effect, the use of the first inorganic particles and the second inorganic particles satisfying the relationship between the specific compressive strength and the specific aspect ratio greatly contributes.

From the viewpoint of more effectively demonstrating the effects of the present invention, the compressive strength at the time of 20% compression of the first inorganic particles and the compressive strength at the time of 20% compression of the second inorganic particles The absolute value of the difference is preferably 1.5 N / mm ² or less. From the viewpoint of more effectively demonstrating the effect of the present invention, the compressive strength at 30% compression of the first inorganic particles is equal to the compressive strength at 30% compression of the second inorganic particles. It is preferably the same or smaller, and more preferably smaller than the compressive strength at 30% compression of the second inorganic particles.

  When the first inorganic particles and the second inorganic particles satisfy the above compressive strength relationship and a compression force is applied by a press or the like, at the initial stage of the compression, The compressive strength (hardness) of the inorganic particles is relatively lower than the compressive strength (hardness) of the first inorganic particles. For this reason, the first inorganic particles are not excessively deformed or disintegrated, and the second inorganic particles are appropriately deformed or disintegrated. Further, at the initial stage of compression, the press pressure at which the deformation or collapse of the second inorganic particles occurs is lower than the press pressure at which the deformation or collapse of the first inorganic particles occurs. At this time, the second inorganic particles that have been appropriately deformed or collapsed can fill the gaps between the first inorganic particles. In the latter stage of compression, the compressive strength (hardness) of the first inorganic particles is relatively lower than the compressive strength (hardness) of the second inorganic particles. At this time, since the second inorganic particles are concentrated around the first inorganic particles, it is possible to prevent the first inorganic particles from being excessively collapsed. In addition, the first inorganic particles can be deformed so as to fill the gaps between the dense second inorganic particles. As a result, the effect of the present invention is more effectively exhibited.

(First inorganic particles and second inorganic particles)
In the resin material according to the present invention, the compressive strength at the time of 10% compression of the first inorganic particles is 2 N / mm ² or less. From the viewpoint of more effectively increasing the insulation and thermal conductivity, the compressive strength at the time of 10% compression of the first inorganic particles is preferably 1.7 N / mm ² or less. The lower limit of the compressive strength at the time of 10% compression of the first inorganic particles is not particularly limited. Compressive strength at 10 percent compression of the first inorganic particles may be 0.1 N / mm ² or more.

From the viewpoint of enhancing the insulating property and thermal conductivity more effectively, the compressive strength at 20 percent compression of the first inorganic particles preferably 3N / mm ² or less, more preferably 2.5 N / mm ² or less. The lower limit of the compressive strength at the time of 20% compression of the first inorganic particles is not particularly limited. The compressive strength at the time of 20% compression of the first inorganic particles may be 1 N / mm ² or more.

From the viewpoint of enhancing the insulating property and thermal conductivity more effectively, the compressive strength at 30% compression of the first inorganic particles preferably 4N / mm ² or less, more preferably 3N / mm ² It is as follows. The lower limit of the compression strength at the time of 30% compression of the first inorganic particles is not particularly limited. The compressive strength at the time of 30% compression of the first inorganic particles may be 1 N / mm ² or more.

In the resin material according to the present invention, the compressive strength at the time of 10% compression of the second inorganic particles is 2 N / mm ² or less. From the viewpoint of more effectively increasing the insulation and thermal conductivity, the compressive strength at the time of compression of 10% of the second inorganic particles is preferably 1.5 N / mm ² or less, more preferably 1. 2 N / mm ² or less. The lower limit of the compressive strength at the time of 10% compression of the second inorganic particles is not particularly limited. The compressive strength at the time of 10% compression of the second inorganic particles may be 0.1 N / mm ² or more.

From the viewpoint of more effectively increasing the insulation and thermal conductivity, the compressive strength at 20% compression of the second inorganic particles is preferably 3 N / mm ² or less, more preferably 2 N / mm ^2. It is as follows. The lower limit of the compression strength at the time of 20% compression of the second inorganic particles is not particularly limited. The compressive strength at the time of 20% compression of the second inorganic particles may be 1 N / mm ² or more.

From the viewpoint of more effectively increasing the insulation and thermal conductivity, the compressive strength at 30% compression of the second inorganic particles is preferably 4 N / mm ² or less, more preferably 3 N / mm ^2. It is as follows. The lower limit of the compression strength at the time of 30% compression of the second inorganic particles is not particularly limited. The compressive strength at the time of 30% compression of the second inorganic particles may be 1 N / mm ² or more.

  From the viewpoint of more effectively increasing the insulation and thermal conductivity, the compression strength of the first inorganic particles at 30% compression is the compression strength of the second inorganic particles at 30% compression. It is preferably the same as or smaller than the above, and more preferably smaller than the compressive strength at the time of 30% compression of the second inorganic particles.

From the viewpoint of further effectively increasing the insulation and thermal conductivity, the compressive strength of the first inorganic particles at 10% compression and the compressive strength of the second inorganic particles at 10% compression the absolute value of the difference, preferably 1N / mm ² or less, and more preferably not more than 0.8N / mm ^2. The compressive strength at the time of 10% compression of the first inorganic particles and the compressive strength at the time of 10% compression of the second inorganic particles may be the same.

From the viewpoint of more effectively increasing the insulating properties and the thermal conductivity, the compressive strength of the first inorganic particles during compression of 20% and the compressive strength of the second inorganic particles during compression of 20% the absolute value of the difference, preferably 1.5 N / mm ² or less, more preferably 1N / mm ² or less. The absolute value of the difference between the compressive strength at the time of 20% compression of the first inorganic particles and the compressive strength at the time of 20% compression of the second inorganic particles may be 0 N / mm ² or more. The compressive strength at the time of 20% compression of the first inorganic particles and the compressive strength at the time of 20% compression of the second inorganic particles may be the same.

From the viewpoint of more effectively increasing the insulation and thermal conductivity, the compressive strength of the first inorganic particles during compression of 30% and the compressive strength of the second inorganic particles during compression of 30% the absolute value of the difference, preferably 0.1 N / mm ² or more, more preferably 0.2 N / mm ² or more, preferably 1.5 N / mm ² or less, more preferably in 1N / mm ² or less . The compression strength at the time of 30% compression of the first inorganic particles and the compression strength at the time of 30% compression of the second inorganic particles may be the same.

  The compressive strength at the time of compression of 10%, 20%, and 30% of the first inorganic particles and the second inorganic particles can be measured as follows.

  Using a diamond compression column as a compression member, the smooth end surface of the compression member is lowered toward the inorganic particles using a micro compression tester to compress the inorganic particles. As a result of the measurement, the relationship between the compression load value and the compression displacement can be obtained. The compression load value per unit area is calculated using the average cross-sectional area calculated using the particle size of the inorganic particles, and this is compressed. Strength. Further, the compression rate is calculated from the compression displacement and the particle size of the inorganic particles, and the relationship between the compression strength and the compression rate is obtained. The inorganic particles to be measured are observed using a microscope, and inorganic particles having a particle size of ± 10% are selected and measured. In addition, the compression strength at each compression rate is calculated as an average compression strength obtained by averaging 20 measurement results. As the micro compression tester, for example, “Micro compression tester HM2000” manufactured by Fischer Instruments is used. The compression ratio can be calculated by (compression ratio = compression displacement / average particle diameter × 100).

  The compressive strength may be measured using inorganic particles before blending with the resin material, or may be measured using inorganic particles recovered by removing the binder resin from the resin material. Examples of the method for removing the binder resin from the resin material include a method in which the resin material is heat-treated at a high temperature of 600 ° C. for 5 hours. The method for removing the binder resin from the resin material may be the above-described method or other methods.

  From the viewpoint of more effectively increasing the insulation and thermal conductivity, the particle diameter of the first inorganic particles is preferably 20 μm or more, more preferably 25 μm or more, preferably 120 μm or less, more preferably 100 μm or less.

  From the viewpoint of more effectively increasing the insulation and thermal conductivity, the particle diameter of the second inorganic particles is preferably 10 μm or more, more preferably 20 μm or more, preferably 50 μm or less, more preferably 45 μm or less.

  The particle diameters of the first inorganic particles and the second inorganic particles are preferably average particle diameters obtained by averaging the particle diameters on a volume basis. The particle diameters of the first inorganic particles and the second inorganic particles can be measured using a “laser diffraction particle size distribution analyzer” manufactured by Horiba, Ltd. The particle diameters of the first inorganic particles and the second inorganic particles are preferably calculated by sampling 3 g of each inorganic particle and averaging the particle diameter of each inorganic particle contained therein. Regarding the calculation method of the average particle size, the particle size (d50) of the inorganic particles when the cumulative volume is 50% in each of the first inorganic particles and the second inorganic particles may be adopted as the average particle size. preferable.

  From the viewpoint of more effectively increasing the insulation and thermal conductivity, the aspect ratio of the first inorganic particles is preferably 3 or less, more preferably 2 or less. The lower limit of the aspect ratio of the first inorganic particles is not particularly limited. The aspect ratio of the first inorganic particles may be 1 or more.

  From the viewpoint of more effectively increasing the insulation and thermal conductivity, the aspect ratio of the second inorganic particles is preferably 3 or less, more preferably 2 or less. The lower limit of the aspect ratio of the second inorganic particles is not particularly limited. The aspect ratio of the second inorganic particles may be 1 or more.

  The aspect ratio of the first inorganic particles and the second inorganic particles indicates a major axis / minor axis. The aspect ratio of the first inorganic particles and the second inorganic particles is preferably an average aspect ratio obtained by averaging the aspect ratios of the plurality of inorganic particles. The average aspect ratio of the first inorganic particles and the second inorganic particles was determined by observing 50 arbitrarily selected inorganic particles with an electron microscope or an optical microscope, and the average value of the major axis / minor axis of each inorganic particle. It is calculated | required by calculating.

  From the viewpoint of more effectively increasing the thermal conductivity, the thermal conductivity of the first inorganic particles is preferably 5 W / m · K or more, more preferably 10 W / m · K or more. The upper limit of the thermal conductivity of the first inorganic particles is not particularly limited. The thermal conductivity of the first inorganic particles may be 1000 W / m · K or less.

  From the viewpoint of further effectively increasing the thermal conductivity, the thermal conductivity of the second inorganic particles is preferably 5 W / m · K or more, more preferably 10 W / m · K or more. The upper limit of the thermal conductivity of the second inorganic particles is not particularly limited. The second inorganic particles may have a thermal conductivity of 1000 W / m · K or less.

  From the viewpoint of more effectively increasing the insulation and thermal conductivity, the total content of the first inorganic particles and the second inorganic particles in 100 volume% of the resin material is preferably 20 volumes. % Or more, more preferably 45% by volume or more, preferably 80% by volume or less, more preferably 70% by volume or less.

  From the viewpoint of more effectively increasing the insulation and thermal conductivity, the first inorganic particles are preferably boron nitride aggregated particles, and the second inorganic particles are boron nitride aggregated particles. It is preferable. The boron nitride aggregated particles are preferably secondary particles obtained by aggregating primary particles of boron nitride. The primary particles of the first inorganic particles are preferably boron nitride, and the primary particles of the second inorganic particles are preferably boron nitride.

  It does not specifically limit as a manufacturing method of the said boron nitride aggregate particle, A spray-drying method, a fluidized-bed granulation method, etc. are mentioned. The method for producing the boron nitride aggregated particles is preferably a spray drying (also called spray drying) method. The spray drying method can be classified into a two-fluid nozzle method, a disk method (also called a rotary method), an ultrasonic nozzle method, and the like depending on the spray method, and any of these methods can be applied. From the viewpoint of more easily controlling the total pore volume, the ultrasonic nozzle method is preferable.

  The boron nitride agglomerated particles are preferably manufactured using primary particles of boron nitride as a material. The boron nitride used as the material for the boron nitride agglomerated particles is not particularly limited. Examples thereof include boron nitride produced from a nitrogen compound and boron nitride produced from sodium borohydride and ammonium chloride. From the viewpoint of further effectively increasing the thermal conductivity of the boron nitride aggregated particles, the boron nitride used as the material of the boron nitride aggregated particles is preferably hexagonal boron nitride.

  Moreover, as a manufacturing method of boron nitride aggregated particles, a granulation step is not necessarily required. It may be boron nitride aggregated particles formed by spontaneously concentrating boron nitride primary particles as the boron nitride crystal grows. Moreover, in order to make the particle diameter of boron nitride aggregated particles uniform, pulverized boron nitride aggregated particles may be used.

  From the viewpoint of more effectively increasing the insulating properties and the thermal conductivity, the first inorganic particles are in the range in which the aspect ratio of the primary particles constituting the inorganic particles is described later, and the compressive strength is in the range described above. And may be composed of two or more kinds of inorganic particles having different particle diameters. From the viewpoint of more effectively increasing the insulation and thermal conductivity, the second inorganic particles are in the range in which the aspect ratio of the primary particles constituting the inorganic particles is described later, and the compression strength is in the range described above. And may be composed of two or more kinds of inorganic particles having different particle diameters.

  From the viewpoint of further effectively increasing the insulating properties and the thermal conductivity, the resin material contains the first inorganic particles and the second inorganic particles in addition to the first inorganic particles and the second inorganic particles. The 3rd inorganic particle which is not this inorganic particle may be included. From the viewpoint of more effectively increasing the insulation and thermal conductivity, the resin material preferably contains the third inorganic particles.

  The third inorganic particles are preferably aggregated particles. The third inorganic particles are preferably secondary particles obtained by agglomerating primary particles of boron nitride.

Primary particles constituting the first inorganic particles and the second inorganic particles:
From the viewpoint of more effectively increasing the insulation and thermal conductivity, from the viewpoint of more effectively suppressing variation in the dielectric breakdown strength, and from the viewpoint of further effectively improving the adhesiveness, the first inorganic The average major axis of the primary particles constituting the particles is preferably 2 μm or more, more preferably 3 μm or more, preferably 20 μm or less, more preferably 15 μm or less.

  From the viewpoint of more effectively increasing the insulation and thermal conductivity, from the viewpoint of more effectively suppressing variation in the dielectric breakdown strength, and from the viewpoint of further increasing the adhesiveness more effectively, the second inorganic The average major axis of the primary particles constituting the particles is preferably 3 μm or more, more preferably 4 μm or more, preferably 15 μm or less, more preferably 10 μm or less.

  The average major axis of the primary particles constituting the first inorganic particles and the second inorganic particles can be calculated as follows.

  From an electron microscope image of a cross section of a laminate after thermosetting by a laminate or a press produced by mixing primary particles constituting the first inorganic particles and the second inorganic particles and a thermosetting resin, etc., The major axis of primary particles constituting each of 50 arbitrarily selected inorganic particles is measured, and an average value is calculated.

  In the resin material according to the present invention, the aspect ratio of the primary particles constituting the first inorganic particles is 7 or more. From the viewpoint of more effectively increasing the insulation and thermal conductivity, from the viewpoint of more effectively suppressing variation in the dielectric breakdown strength, and from the viewpoint of further effectively improving the adhesiveness, the first inorganic The aspect ratio of the primary particles constituting the particles is preferably 8 or more, more preferably 10 or more. The upper limit of the aspect ratio of the primary particles constituting the first inorganic particles is not particularly limited. The aspect ratio of the primary particles constituting the first inorganic particles may be 15 or less.

  In the resin material according to the present invention, the aspect ratio of the primary particles constituting the second inorganic particles is less than 7. From the viewpoint of more effectively increasing the insulation and thermal conductivity, from the viewpoint of more effectively suppressing variation in the dielectric breakdown strength, and from the viewpoint of further increasing the adhesiveness more effectively, the second inorganic The aspect ratio of the primary particles constituting the particles is preferably 6.5 or less, more preferably 6 or less. The lower limit of the aspect ratio of the primary particles constituting the second inorganic particles is not particularly limited. The aspect ratio of the primary particles constituting the second inorganic particles may be 3 or more.

  The aspect ratio of the primary particles constituting the first inorganic particles and the second inorganic particles indicates a major axis / minor axis. The aspect ratio of the primary particles constituting the first inorganic particles and the second inorganic particles can be calculated as follows.

  From an electron microscope image of a cross section of a laminate after thermosetting by a laminate or a press produced by mixing primary particles constituting the first inorganic particles and the second inorganic particles and a thermosetting resin, etc., The major axis / minor axis of the primary particles constituting each of 50 arbitrarily selected inorganic particles are measured, and the average value is calculated.

  From the viewpoint of more effectively increasing the insulation and thermal conductivity, in the primary particles constituting the first boron nitride aggregated particles and the second boron nitride aggregated particles, all the primary particles are debris. The particles need not be shaped particles, and may contain at least one particle having a bent shape. The bent particles are divided into two particles at the bent portion, and the major axis / minor axis of each particle is measured. The major axis / minor axis of the longer major axis is the major axis / longer axis The minor axis. The aspect ratio is calculated from the obtained major axis / minor axis value.

  In the electron microscope image of the cross section of the laminate, the shape of the primary particles constituting the inorganic particles in the laminate can be confirmed relatively clearly. Therefore, it can be judged from the electron microscope image of a cross section of the laminate that two types of primary particles having different aspect ratios are used. Further, when the inorganic particles are aggregated particles, aggregated particles having the same aspect ratio are gathered within a certain range. Therefore, it can also be judged from the electron microscope image of a cross section of the laminate that aggregated particles having different aspect ratios are used.

(Binder resin)
The resin material according to the present invention includes a binder resin. The binder resin is not particularly limited. A known insulating resin is used as the binder resin. The binder resin preferably includes a thermoplastic component (thermoplastic compound) or a curable component, and more preferably includes a curable component. Examples of the curable component include a thermosetting component and a photocurable component. The thermosetting component preferably contains a thermosetting compound and a thermosetting agent. It is preferable that the said photocurable component contains a photocurable compound and a photoinitiator. The binder resin preferably contains a thermosetting component. As for the said binder resin, only 1 type may be used and 2 or more types may be used together.

  “(Meth) acryloyl group” refers to an acryloyl group and a methacryloyl group. “(Meth) acryl” refers to acrylic and methacrylic. “(Meth) acrylate” refers to acrylate and methacrylate.

(Thermosetting component: thermosetting compound)
Examples of the thermosetting compounds include styrene compounds, phenoxy compounds, oxetane compounds, epoxy compounds, episulfide compounds, (meth) acrylic compounds, phenolic compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds, and polyimide compounds. Can be mentioned. As for the said thermosetting compound, only 1 type may be used and 2 or more types may be used together.

  As the thermosetting compound, (A1) a thermosetting compound having a molecular weight of less than 10,000 (sometimes simply referred to as (A1) thermosetting compound) may be used. A thermosetting compound having a molecular weight (may be simply referred to as (A2) thermosetting compound) may be used, and both (A1) thermosetting compound and (A2) thermosetting compound are used. It may be used.

  The content of the thermosetting compound in 100% by volume of the resin material is preferably 10% by volume or more, more preferably 20% by volume or more, preferably 90% by volume or less, more preferably 80% by volume or less. . When the content of the thermosetting compound is not less than the above lower limit, the adhesiveness and heat resistance of the cured product are further enhanced. When the content of the thermosetting compound is not more than the above upper limit, the coating property of the resin material is further enhanced.

(A1) Thermosetting compound having a molecular weight of less than 10,000:
(A1) As a thermosetting compound, the thermosetting compound which has a cyclic ether group is mentioned. Examples of the cyclic ether group include an epoxy group and an oxetanyl group. The thermosetting compound having a cyclic ether group is preferably a thermosetting compound having an epoxy group or an oxetanyl group. (A1) As for a thermosetting compound, only 1 type may be used and 2 or more types may be used together.

  The (A1) thermosetting compound may contain (A1a) a thermosetting compound having an epoxy group (sometimes simply referred to as (A1a) a thermosetting compound), and (A1b) an oxetanyl group. A thermosetting compound (which may be simply referred to as (A1b) thermosetting compound).

  From the viewpoint of further effectively increasing the heat resistance and moisture resistance of the cured product, the (A1) thermosetting compound preferably has an aromatic skeleton.

  The aromatic skeleton is not particularly limited, and examples thereof include naphthalene skeleton, fluorene skeleton, biphenyl skeleton, anthracene skeleton, pyrene skeleton, xanthene skeleton, adamantane skeleton, and bisphenol A skeleton. From the viewpoint of further effectively increasing the cold heat cycle characteristics and heat resistance of the cured product, the aromatic skeleton is preferably a biphenyl skeleton or a fluorene skeleton.

  (A1a) The thermosetting compound includes an epoxy monomer having a bisphenol skeleton, an epoxy monomer having a dicyclopentadiene skeleton, an epoxy monomer having a naphthalene skeleton, an epoxy monomer having an adamantane skeleton, an epoxy monomer having a fluorene skeleton, and a biphenyl skeleton. Epoxy monomers having a bi (glycidyloxyphenyl) methane skeleton, epoxy monomers having a xanthene skeleton, epoxy monomers having an anthracene skeleton, and epoxy monomers having a pyrene skeleton. These hydrogenated products or modified products may be used. (A1a) As for a thermosetting compound, only 1 type may be used and 2 or more types may be used together.

  Examples of the epoxy monomer having a bisphenol skeleton include an epoxy monomer having a bisphenol A type, bisphenol F type, or bisphenol S type bisphenol skeleton.

  Examples of the epoxy monomer having a dicyclopentadiene skeleton include dicyclopentadiene dioxide and a phenol novolac epoxy monomer having a dicyclopentadiene skeleton.

  Examples of the epoxy monomer having a naphthalene skeleton include 1-glycidylnaphthalene, 2-glycidylnaphthalene, 1,2-diglycidylnaphthalene, 1,5-diglycidylnaphthalene, 1,6-diglycidylnaphthalene, 1,7-diglycidyl. Naphthalene, 2,7-diglycidylnaphthalene, triglycidylnaphthalene, 1,2,5,6-tetraglycidylnaphthalene and the like can be mentioned.

  Examples of the epoxy monomer having an adamantane skeleton include 1,3-bis (4-glycidyloxyphenyl) adamantane and 2,2-bis (4-glycidyloxyphenyl) adamantane.

  Examples of the epoxy monomer having a fluorene skeleton include 9,9-bis (4-glycidyloxyphenyl) fluorene, 9,9-bis (4-glycidyloxy-3-methylphenyl) fluorene, and 9,9-bis (4- Glycidyloxy-3-chlorophenyl) fluorene, 9,9-bis (4-glycidyloxy-3-bromophenyl) fluorene, 9,9-bis (4-glycidyloxy-3-fluorophenyl) fluorene, 9,9-bis (4-Glycidyloxy-3-methoxyphenyl) fluorene, 9,9-bis (4-glycidyloxy-3,5-dimethylphenyl) fluorene, 9,9-bis (4-glycidyloxy-3,5-dichlorophenyl) Fluorene and 9,9-bis (4-glycidyloxy-3,5-dibromophenyl) Fluorene, and the like.

  Examples of the epoxy monomer having a biphenyl skeleton include 4,4'-diglycidylbiphenyl and 4,4'-diglycidyl-3,3 ', 5,5'-tetramethylbiphenyl.

  Examples of the epoxy monomer having a bi (glycidyloxyphenyl) methane skeleton include 1,1′-bi (2,7-glycidyloxynaphthyl) methane, 1,8′-bi (2,7-glycidyloxynaphthyl) methane, 1,1′-bi (3,7-glycidyloxynaphthyl) methane, 1,8′-bi (3,7-glycidyloxynaphthyl) methane, 1,1′-bi (3,5-glycidyloxynaphthyl) methane 1,8'-bi (3,5-glycidyloxynaphthyl) methane, 1,2'-bi (2,7-glycidyloxynaphthyl) methane, 1,2'-bi (3,7-glycidyloxynaphthyl) Examples include methane and 1,2′-bi (3,5-glycidyloxynaphthyl) methane.

  Examples of the epoxy monomer having a xanthene skeleton include 1,3,4,5,6,8-hexamethyl-2,7-bis-oxiranylmethoxy-9-phenyl-9H-xanthene.

  Specific examples of the (A1b) thermosetting compound include, for example, 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] biphenyl, 1,4-benzenedicarboxylic acid bis [(3-ethyl- 3-oxetanyl) methyl] ester, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] benzene, oxetane-modified phenol novolak, and the like. (A1b) Only 1 type may be used for a thermosetting compound and 2 or more types may be used together.

  From the viewpoint of further improving the heat resistance of the cured product, the (A1) thermosetting compound preferably includes a thermosetting compound having two or more cyclic ether groups.

  From the viewpoint of further improving the heat resistance of the cured product, the content of the thermosetting compound having two or more cyclic ether groups is preferably 70% by weight or more in 100% by weight of the (A1) thermosetting compound. More preferably, it is 80% by weight or more, and preferably 100% by weight or less. (A1) The content of the thermosetting compound having two or more cyclic ether groups in 100% by weight of the thermosetting compound may be 10% by weight or more and 100% by weight or less. Further, the whole (A1) thermosetting compound may be a thermosetting compound having two or more cyclic ether groups.

  (A1) The molecular weight of the thermosetting compound is less than 10,000. (A1) The molecular weight of the thermosetting compound is preferably 200 or more, preferably 1200 or less, more preferably 600 or less, and even more preferably 550 or less. (A1) When the molecular weight of the thermosetting compound is not less than the above lower limit, the adhesiveness of the surface of the cured product is lowered, and the handleability of the resin material is further enhanced. (A1) When the molecular weight of the thermosetting compound is not more than the above upper limit, the adhesiveness of the cured product is further enhanced. Furthermore, the cured product is hard and hard to be brittle, and the adhesiveness of the cured product is further enhanced.

  In this specification, (A1) the molecular weight of the thermosetting compound is (A1) when the thermosetting compound is not a polymer, and (A1) when the structural formula of the thermosetting compound can be specified. It means the molecular weight that can be calculated from the structural formula. When the thermosetting compound (A1) is a polymer, it means the weight average molecular weight. The weight average molecular weight is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC). In gel permeation chromatography (GPC) measurement, tetrahydrofuran is preferably used as the eluent.

  In 100% by volume of the resin material, the content of the (A1) thermosetting compound is preferably 10% by volume or more, more preferably 20% by volume or more, preferably 90% by volume or less, more preferably 80% by volume or less. It is. (A1) When the content of the thermosetting compound is not less than the above lower limit, the adhesiveness and heat resistance of the cured product are further enhanced. (A1) When the content of the thermosetting compound is not more than the above upper limit, the coating property of the resin material is further enhanced.

(A2) Thermosetting compound having a molecular weight of 10,000 or more:
(A2) The thermosetting compound is a thermosetting compound having a molecular weight of 10,000 or more. Since the molecular weight of the (A2) thermosetting compound is 10,000 or more, the (A2) thermosetting compound is generally a polymer, and the above molecular weight generally means a weight average molecular weight.

  From the viewpoint of further effectively increasing the heat resistance and moisture resistance of the cured product, the (A2) thermosetting compound preferably has an aromatic skeleton. (A2) When the thermosetting compound is a polymer and (A2) the thermosetting compound has an aromatic skeleton, (A2) the thermosetting compound has an aromatic skeleton in any part of the whole polymer. What is necessary is just to have, it may have in the main chain frame | skeleton, and you may have in a side chain. From the viewpoint of further increasing the heat resistance of the cured product and further increasing the moisture resistance of the cured product, the (A2) thermosetting compound preferably has an aromatic skeleton in the main chain skeleton. (A2) As for a thermosetting compound, only 1 type may be used and 2 or more types may be used together.

  The aromatic skeleton is not particularly limited, and examples thereof include naphthalene skeleton, fluorene skeleton, biphenyl skeleton, anthracene skeleton, pyrene skeleton, xanthene skeleton, adamantane skeleton, and bisphenol A skeleton. From the viewpoint of further effectively increasing the cold heat cycle characteristics and heat resistance of the cured product, the aromatic skeleton is preferably a biphenyl skeleton or a fluorene skeleton.

  (A2) The thermosetting compound is not particularly limited. Styrene resin, phenoxy resin, oxetane resin, epoxy resin, episulfide compound, (meth) acrylic resin, phenol resin, amino resin, unsaturated polyester resin, polyurethane resin, silicone Examples thereof include resins and polyimide resins.

  From the viewpoint of suppressing the oxidative deterioration of the cured product, further improving the heat cycle resistance and heat resistance of the cured product, and further reducing the water absorption of the cured product, (A2) the thermosetting compound is a styrene resin, It is preferably a phenoxy resin or an epoxy resin, more preferably a phenoxy resin or an epoxy resin, and further preferably a phenoxy resin. In particular, use of a phenoxy resin or an epoxy resin further increases the heat resistance of the cured product. Moreover, use of a phenoxy resin further lowers the elastic modulus of the cured product and further improves the cold-heat cycle characteristics of the cured product. In addition, the (A2) thermosetting compound does not need to have cyclic ether groups, such as an epoxy group.

  As the styrene resin, specifically, a homopolymer of a styrene monomer, a copolymer of a styrene monomer and an acrylic monomer, or the like can be used. Styrene polymers having a styrene-glycidyl methacrylate structure are preferred.

  Examples of the styrene monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, and pn-. Butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2,4-dimethyl Examples include styrene and 3,4-dichlorostyrene.

  Specifically, the phenoxy resin is, for example, a resin obtained by reacting an epihalohydrin with a divalent phenol compound, or a resin obtained by reacting a divalent epoxy compound with a divalent phenol compound.

  The phenoxy resin has a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol A / F mixed skeleton, a naphthalene skeleton, a fluorene skeleton, a biphenyl skeleton, an anthracene skeleton, a pyrene skeleton, a xanthene skeleton, an adamantane skeleton, or a dicyclopentadiene skeleton. It is preferable. More preferably, the phenoxy resin has a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol A / F mixed skeleton, a naphthalene skeleton, a fluorene skeleton, or a biphenyl skeleton, and at least one of the fluorene skeleton and the biphenyl skeleton. More preferably, it has a skeleton. Use of the phenoxy resin having these preferable skeletons further increases the heat resistance of the cured product.

  The epoxy resin is an epoxy resin other than the phenoxy resin. Examples of the epoxy resins include styrene skeleton-containing epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, phenol novolac type epoxy resins, biphenol type epoxy resins, naphthalene type epoxy resins, and fluorene type epoxy resins. , Phenol aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, anthracene type epoxy resin, epoxy resin having adamantane skeleton, epoxy resin having tricyclodecane skeleton, and epoxy resin having triazine nucleus in skeleton Etc.

  (A2) The molecular weight of the thermosetting compound is 10,000 or more. (A2) The molecular weight of the thermosetting compound is preferably 30000 or more, more preferably 40000 or more, preferably 1000000 or less, more preferably 250,000 or less. (A2) When the molecular weight of the thermosetting compound is not less than the above lower limit, the cured product is hardly thermally deteriorated. When the molecular weight of the (A2) thermosetting compound is not more than the above upper limit, the compatibility between the (A2) thermosetting compound and other components is increased. As a result, the heat resistance of the cured product is further increased.

  In 100% by volume of the resin material, the content of the (A2) thermosetting compound is preferably 20% by volume or more, more preferably 30% by volume or more, preferably 60% by volume or less, more preferably 50% by volume or less. It is. (A2) When the content of the thermosetting compound is not less than the above lower limit, the handleability of the resin material is further improved. (A2) When the content of the thermosetting compound is not more than the above upper limit, the coating property of the resin material is further enhanced.

(Thermosetting component: thermosetting agent)
The thermosetting agent is not particularly limited. As the thermosetting agent, a thermosetting agent capable of curing the thermosetting compound can be appropriately used. In the present specification, the thermosetting agent includes a curing catalyst. As for a thermosetting agent, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of further effectively increasing the heat resistance of the cured product, the thermosetting agent preferably has an aromatic skeleton or an alicyclic skeleton. The thermosetting agent preferably includes an amine curing agent (amine compound), an imidazole curing agent, a phenol curing agent (phenol compound), or an acid anhydride curing agent (acid anhydride), and more preferably includes an amine curing agent. preferable. The acid anhydride curing agent includes an acid anhydride having an aromatic skeleton, a water additive of the acid anhydride or a modified product of the acid anhydride, or an acid anhydride having an alicyclic skeleton, It is preferable to include a water additive of an acid anhydride or a modified product of the acid anhydride.

  Examples of the amine curing agent include dicyandiamide, imidazole compounds, diaminodiphenylmethane, and diaminodiphenylsulfone. From the viewpoint of more effectively increasing the adhesiveness of the cured product, the amine curing agent is more preferably dicyandiamide or an imidazole compound. From the viewpoint of more effectively increasing the storage stability of the resin material, the thermosetting agent preferably includes a curing agent having a melting point of 180 ° C. or higher, and includes an amine curing agent having a melting point of 180 ° C. or higher. Is more preferable.

  Examples of the imidazole curing agent include 2-undecylimidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 1-benzyl. 2-methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2- Undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6- [2 '-Methyl Midazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-undecylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6 [2′-Ethyl-4′-methylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine Isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-dihydroxymethylimidazole Can be mentioned.

  Examples of the phenol curing agent include phenol novolak, o-cresol novolak, p-cresol novolak, t-butylphenol novolak, dicyclopentadiene cresol, polyparavinylphenol, bisphenol A type novolak, xylylene modified novolak, decalin modified novolak, poly ( And di-o-hydroxyphenyl) methane, poly (di-m-hydroxyphenyl) methane, and poly (di-p-hydroxyphenyl) methane. From the viewpoint of further effectively increasing the flexibility of the cured product and the flame retardancy of the cured product, the phenol curing agent is a phenol resin having a melamine skeleton, a phenol resin having a triazine skeleton, or a phenol resin having an allyl group. It is preferable that

  Commercially available products of the phenol curing agent include MEH-8005, MEH-8010, and MEH-8015 (all of which are manufactured by Meiwa Kasei Co., Ltd.), YLH903 (manufactured by Mitsubishi Chemical Corporation), LA-7052, LA-7054, and LA-7751. LA-1356 and LA-3018-50P (all of which are manufactured by DIC Corporation), PS6313 and PS6492 (all of which are manufactured by Gunei Chemical Co., Ltd.), and the like.

  Examples of the acid anhydride having an aromatic skeleton, a water additive of the acid anhydride, or a modified product of the acid anhydride include, for example, a styrene / maleic anhydride copolymer, a benzophenone tetracarboxylic acid anhydride, and a pyromellitic acid anhydride. , Trimellitic anhydride, 4,4'-oxydiphthalic anhydride, phenylethynyl phthalic anhydride, glycerol bis (anhydrotrimellitate) monoacetate, ethylene glycol bis (anhydrotrimellitate), methyltetrahydroanhydride Examples include phthalic acid, methylhexahydrophthalic anhydride, and trialkyltetrahydrophthalic anhydride.

  Examples of commercially available acid anhydrides having an aromatic skeleton, water additives of the acid anhydrides, or modified products of the acid anhydrides include SMA Resin EF30, SMA Resin EF40, SMA Resin EF60, and SMA Resin EF80 (any of the above Also manufactured by Sartomer Japan), ODPA-M and PEPA (all manufactured by Manac), Ricacid MTA-10, Ricacid MTA-15, Ricacid TMTA, Ricacid TMEG-100, Ricacid TMEG-200, Ricacid TMEG-300, Ricacid TMEG-500, Ricacid TMEG-S, Ricacid TH, Ricacid HT-1A, Ricacid HH, Ricacid MH-700, Ricacid MT-500, Ricacid DSDA and Ricacid TDA-100 (all of which are manufactured by Shin Nippon Rika Co., Ltd.) PICLON B4400, EPICLON B650, and EPICLON B570 (all manufactured by both DIC Corporation).

  The acid anhydride having an alicyclic skeleton, a water additive of the acid anhydride, or a modified product of the acid anhydride is an acid anhydride having a polyalicyclic skeleton, a water additive of the acid anhydride, or the A modified product of an acid anhydride, or an acid anhydride having an alicyclic skeleton obtained by addition reaction of a terpene compound and maleic anhydride, a water additive of the acid anhydride, or a modified product of the acid anhydride It is preferable. By using these curing agents, the flexibility of the cured product and the moisture resistance and adhesion of the cured product are further increased.

  Examples of the acid anhydride having an alicyclic skeleton, a water addition of the acid anhydride, or a modified product of the acid anhydride include methyl nadic acid anhydride, acid anhydride having a dicyclopentadiene skeleton, and the acid anhydride And the like.

  Examples of commercially available acid anhydrides having the alicyclic skeleton, water additions of the acid anhydrides, or modified products of the acid anhydrides include Ricacid HNA and Ricacid HNA-100 (all of which are manufactured by Shin Nippon Rika Co., Ltd.) , And EpiCure YH306, EpiCure YH307, EpiCure YH308H, EpiCure YH309 (all of which are manufactured by Mitsubishi Chemical Corporation) and the like.

  It is also preferable that the thermosetting agent is methyl nadic anhydride or trialkyltetrahydrophthalic anhydride. Use of methyl nadic anhydride or trialkyltetrahydrophthalic anhydride increases the water resistance of the cured product.

  In 100% by volume of the resin material, the content of the thermosetting agent is preferably 0.1% by volume or more, more preferably 1% by volume or more, preferably 40% by volume or less, more preferably 25% by volume or less. is there. When the content of the thermosetting agent is equal to or higher than the lower limit, it becomes much easier to sufficiently cure the thermosetting compound. When the content of the thermosetting agent is not more than the above upper limit, it is difficult to generate an excessive thermosetting agent that does not participate in curing. For this reason, the heat resistance and adhesiveness of hardened | cured material become still higher.

(Photocurable component: Photocurable compound)
The said photocurable compound will not be specifically limited if it has photocurability. As for the said photocurable compound, only 1 type may be used and 2 or more types may be used together.

  The photocurable compound preferably has two or more ethylenically unsaturated bonds.

  Examples of the group containing an ethylenically unsaturated bond include a vinyl group, an allyl group, and a (meth) acryloyl group. A (meth) acryloyl group is preferred from the viewpoint of effectively advancing the reaction and further suppressing foaming, peeling and discoloration of the cured product. The photocurable compound preferably has a (meth) acryloyl group.

  From the viewpoint of further effectively increasing the adhesion of the cured product, the photocurable compound preferably contains an epoxy (meth) acrylate. From the viewpoint of further effectively increasing the heat resistance of the cured product, the epoxy (meth) acrylate preferably contains a bifunctional epoxy (meth) acrylate and a trifunctional or higher functional epoxy (meth) acrylate. The bifunctional epoxy (meth) acrylate preferably has two (meth) acryloyl groups. The tri- or higher functional epoxy (meth) acrylate preferably has three or more (meth) acryloyl groups.

  Epoxy (meth) acrylate is obtained by reacting (meth) acrylic acid with an epoxy compound. Epoxy (meth) acrylate can be obtained by converting an epoxy group into a (meth) acryloyl group. Since the photocurable compound is cured by light irradiation, the epoxy (meth) acrylate preferably has no epoxy group.

  As the epoxy (meth) acrylate, bisphenol type epoxy (meth) acrylate (for example, bisphenol A type epoxy (meth) acrylate, bisphenol F type epoxy (meth) acrylate, bisphenol S type epoxy (meth) acrylate), cresol novolac type Examples include epoxy (meth) acrylate, amine-modified bisphenol-type epoxy (meth) acrylate, caprolactone-modified bisphenol-type epoxy (meth) acrylate, carboxylic acid anhydride-modified epoxy (meth) acrylate, and phenol novolac-type epoxy (meth) acrylate. .

  In 100% by volume of the resin material, the content of the photocurable compound is preferably 5% by volume or more, more preferably 10% by volume or more, preferably 40% by volume or less, more preferably 30% by volume or less. . The adhesiveness of hardened | cured material becomes it still higher that content of these photocurable compounds is more than the said minimum and below the said upper limit.

(Photocurable component: Photopolymerization initiator)
The photopolymerization initiator is not particularly limited. As said photoinitiator, the photoinitiator which can harden the said photocurable compound by irradiation of light can be used suitably. As for the said photoinitiator, only 1 type may be used and 2 or more types may be used together.

  Examples of the photopolymerization initiator include acylphosphine oxide, halomethylated triazine, halomethylated oxadiazole, imidazole, benzoin, benzoin alkyl ether, anthraquinone, benzanthrone, benzophenone, acetophenone, thioxanthone, benzoate, acridine, phenazine, Examples include titanocene, α-aminoalkylphenone, oxime, and derivatives thereof.

  Examples of the benzophenone photopolymerization initiator include methyl o-benzoylbenzoate and Michler's ketone. EAB (made by Hodogaya Chemical Co., Ltd.) etc. are mentioned as a commercial item of a benzophenone series photoinitiator.

  Examples of commercially available acetophenone photopolymerization initiators include Darocur 1173, Darocur 2959, Irgacure 184, Irgacure 907, and Irgacure 369 (all of which are manufactured by BASF).

  Examples of commercially available benzoin photopolymerization initiators include Irgacure 651 (manufactured by BASF).

  Examples of commercially available acylphosphine oxide photopolymerization initiators include Lucirin TPO and Irgacure 819 (all of which are manufactured by BASF).

  Examples of commercially available thioxanthone photopolymerization initiators include isopropyl thioxanthone and diethyl thioxanthone.

  Examples of commercially available oxime photopolymerization initiators include Irgacure OXE-01 and Irgacure OXE-02 (all of which are manufactured by BASF).

  The content of the photopolymerization initiator with respect to 100 parts by weight of the photocurable compound is preferably 1 part by weight or more, more preferably 3 parts by weight or more, preferably 20 parts by weight or less, more preferably 15 parts by weight. Less than parts by weight. When the content of the photopolymerization initiator is not less than the above lower limit and not more than the above upper limit, the photocurable compound can be favorably photocured.

(Insulating filler)
The resin material according to the present invention may contain an insulating filler. The insulating filler is not the first inorganic particle but not the second inorganic particle. The insulating filler has an insulating property. The insulating filler may be an organic filler or an inorganic filler. As for the said insulating filler, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of more effectively increasing the thermal conductivity, the insulating filler is preferably an inorganic filler. From the viewpoint of more effectively increasing the thermal conductivity, the insulating filler preferably has a thermal conductivity of 10 W / m · K or more.

  From the viewpoint of further effectively increasing the thermal conductivity of the cured product, the thermal conductivity of the insulating filler is preferably 10 W / m · K or more, more preferably 20 W / m · K or more. The upper limit of the thermal conductivity of the insulating filler is not particularly limited. Inorganic fillers having a thermal conductivity of about 300 W / m · K are widely known, and inorganic fillers having a thermal conductivity of about 200 W / m · K are easily available.

  The material of the insulating filler is not particularly limited. Materials for the insulating filler include nitrogen compounds (boron nitride, aluminum nitride, silicon nitride, carbon nitride, titanium nitride, etc.), carbon compounds (silicon carbide, fluorine carbide, boron carbide, titanium carbide, tungsten carbide, diamond, etc.) ), And metal oxides (such as silica, alumina, zinc oxide, magnesium oxide, and beryllium oxide). The material of the insulating filler is preferably the nitrogen compound, the carbon compound or the metal oxide, and more preferably alumina, boron nitride, aluminum nitride, silicon nitride, silicon carbide, zinc oxide or magnesium oxide. preferable. Use of these preferable insulating fillers further increases the thermal conductivity of the cured product.

  The insulating filler is preferably spherical particles, or non-aggregated particles and aggregated particles having an aspect ratio of more than 2. Use of these insulating fillers further increases the thermal conductivity of the cured product. The spherical particles have an aspect ratio of 2 or less.

  The new Mohs hardness of the insulating filler material is preferably 12 or less, more preferably 9 or less. When the new Mohs hardness of the insulating filler material is 9 or less, the workability of the cured product is further enhanced.

  From the viewpoint of further effectively improving the workability of the cured product, the material of the insulating filler is preferably boron nitride, synthetic magnesite, crystalline silica, zinc oxide, or magnesium oxide. The new Mohs hardness of these inorganic filler materials is 9 or less.

  From the viewpoint of increasing the thermal conductivity more effectively, the particle size of the insulating filler is preferably 0.1 μm or more, and preferably 20 μm or less. When the particle diameter is equal to or more than the lower limit, the insulating filler can be easily filled at a high density. When the particle diameter is not more than the above upper limit, the thermal conductivity of the cured product is further increased.

  The said particle diameter means the average particle diameter calculated | required from the particle size distribution measurement result in the volume average measured with the laser diffraction type particle size distribution measuring apparatus. The particle diameter of the insulating filler is preferably calculated by sampling 3 g of the insulating filler and averaging the particle diameter of the insulating filler contained therein. About the calculation method of the average particle diameter of an insulating filler, it is preferable to employ | adopt the particle diameter (d50) of an insulating filler when an accumulation volume is 50% as an average particle diameter.

  From the viewpoint of more effectively increasing the thermal conductivity, the content of the insulating filler in 100% by volume of the resin material is preferably 1% by volume or more, more preferably 3% by volume or more, preferably 20%. Volume% or less, More preferably, it is 10 volume% or less.

(Other ingredients)
The resin material may contain, in addition to the components described above, other components generally used for resin materials such as dispersants, chelating agents, antioxidants, resin sheets, and curable sheets.

(Other details of resin materials and cured products)
The resin material may be a paste or a curable paste. The resin material may be a resin sheet or a curable sheet. When the resin material contains a curable component, a cured product can be obtained by curing the resin material. The said hardened | cured material is a hardened | cured material of the said resin material, and is formed with the said resin material.

  From the viewpoint of more effectively increasing the insulation and thermal conductivity, the resin material may be prepared by laminating two or more resin sheets. Moreover, the resin sheet which concerns on this invention may be sufficient as one layer or more among the resin sheets of two or more layers.

(Laminate)
The laminate according to the present invention includes a heat conductor, an insulating layer, and a conductive layer. The insulating layer is laminated on one surface of the heat conductor. The conductive layer is laminated on the surface of the insulating layer opposite to the heat conductor side. The insulating layer may be laminated on the other surface of the heat conductor. In the laminate according to the present invention, the material of the insulating layer is the resin material described above.

Thermal conductor:
The thermal conductivity of the thermal conductor is preferably 10 W / m · K or more. An appropriate heat conductor can be used as the heat conductor. The heat conductor is preferably a metal material. Examples of the metal material include a metal foil and a metal plate. The heat conductor is preferably the metal foil or the metal plate, and more preferably the metal plate.

  Examples of the metal material include aluminum, copper, gold, silver, and a graphite sheet. From the viewpoint of more effectively increasing the thermal conductivity, the metal material is preferably aluminum, copper, or gold, and more preferably aluminum or copper.

Conductive layer:
The metal for forming the conductive layer is not particularly limited. Examples of the metal include gold, silver, palladium, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, silicon, and tungsten. , Molybdenum, and alloys thereof. Examples of the metal include tin-doped indium oxide (ITO) and solder. From the viewpoint of more effectively increasing the thermal conductivity, aluminum, copper or gold is preferable, and aluminum or copper is more preferable.

  The method for forming the conductive layer is not particularly limited. Examples of the method for forming the conductive layer include a method by electroless plating, a method by electroplating, and a method in which the insulating layer and the metal foil are thermocompression bonded. Since the formation of the conductive layer is simple, a method of thermocompression bonding the insulating layer and the metal foil is preferable.

  FIG. 1 is a cross-sectional view schematically showing a resin sheet according to an embodiment of the present invention. In FIG. 1, the actual size and thickness are different for convenience of illustration.

  A resin sheet 1 shown in FIG. 1 includes a binder resin 11, first inorganic particles 12, and second inorganic particles 13. The 1st inorganic particle 12 and the 2nd inorganic particle 13 are the 1st inorganic particle and the 2nd inorganic particle which were mentioned above, respectively, and the 1st inorganic particle 12 and the 2nd inorganic particle 13 are boron nitride aggregation, respectively. Particles are preferred. The aspect ratio of the primary particles constituting the first inorganic particles 12 is different from the aspect ratio of the primary particles constituting the second inorganic particles 13.

  In the resin sheet 1 according to the present embodiment, the binder resin 11 includes a curable component. The binder resin 11 may include a thermosetting component including a thermosetting compound and a thermosetting agent, or may include a photocurable component including a photocurable compound and a photopolymerization initiator. The binder resin is preferably not completely cured. The binder resin may be B-staged by heating or the like. The binder resin may be a B-staged product that has been B-staged.

  In the resin sheet, voids may exist inside the sheet. In the resin sheet, a void may exist between the first inorganic particles and the second inorganic particles.

  FIG. 2 is a cross-sectional view schematically showing a laminate obtained using the resin material according to one embodiment of the present invention. In FIG. 2, the actual size and thickness are different for convenience of illustration.

  The laminated body 21 shown in FIG. 2 includes a heat conductor 22, an insulating layer 23, and a conductive layer 24. The heat conductor 22, the insulating layer 23, and the conductive layer 24 are the above-described heat conductor, insulating layer, and conductive layer. In FIG. 2, the resin sheet 1 shown in FIG. 1 is used as the insulating layer 23.

  The heat conductor 22 has one surface 22a (first surface) and the other surface 22b (second surface). The insulating layer 23 has one surface 23a (first surface) and the other surface 23b (second surface). The conductive layer 24 has one surface 24a (first surface) and the other surface 24b (second surface).

  A conductive layer 24 is laminated on one surface 23 a (first surface) side of the insulating layer 23. On the other surface 23b (second surface) side of the insulating layer 23, the heat conductor 22 is laminated. An insulating layer 23 is stacked on the other surface 24 b (second surface) side of the conductive layer 24. An insulating layer 23 is laminated on one surface 22 a (first surface) side of the heat conductor 22. An insulating layer 23 is disposed between the heat conductor 22 and the conductive layer 24.

  The manufacturing method of the said laminated body is not specifically limited. As a manufacturing method of the said laminated body, the method etc. which laminate | stack the said heat conductor, the said insulating layer, and the said conductive layer, and heat-press-bond by vacuum press etc. are mentioned.

  In the laminated body 21 according to this embodiment, the insulating layer 23 includes the cured product portion 14, the first inorganic particles 12, and the second inorganic particles 13. The insulating layer 23 is formed by the resin sheet 1 shown in FIG. The insulating layer is preferably formed by heat-pressing the resin sheet with a vacuum press or the like.

  In the laminate 21 according to this embodiment, the first inorganic particles 12 may be deformed by a compression force such as a press. It is preferable that the first inorganic particles 12 are not collapsed by a compression force such as a press. The first inorganic particles 12 are preferably aggregated particles (secondary particles). The first inorganic particles 12 are preferably present in the form of aggregated particles (secondary particles) in the cured product.

  In the laminated body 21 according to the present embodiment, the second inorganic particles 13 may be collapsed by a compression force such as a press. The second inorganic particles 13 may be deformed aggregated particles (secondary particles), or may be primary particles by the collapse of the aggregated particles (secondary particles). The second inorganic particles 13 may exist in the form of deformed aggregated particles (secondary particles) in the cured product, and exist in the form of primary particles by the collapse of the aggregated particles (secondary particles). You may do it.

  In the cured product portion 14, the second inorganic particles 13 are deformed or collapsed around the first inorganic particles 12. The deformed or disintegrated second inorganic particles 13 are present between the first inorganic particles 12. The deformed or collapsed second inorganic particles 13 fill the voids existing between the first inorganic particles 12. The laminated body 21 can fill the gaps between the first inorganic particles 12 with the second inorganic particles 13, can effectively improve the insulation, and more effectively vary the dielectric breakdown strength variation. Can be suppressed. Furthermore, since the voids between the particles can be filled with the binder resin present in the first inorganic particles 12, the insulation can be effectively improved, and the variation in the dielectric breakdown strength can be further effectively suppressed. be able to.

  In the cured product portion 14, the deformed or collapsed second inorganic particles 13 are present between the first inorganic particles 12. The deformed or collapsed second inorganic particles 13 form a heat conduction path between the first inorganic particles 12. In the laminated body 21, thermal conductivity can be effectively increased not only in the plane direction but also in the thickness direction (press direction). Moreover, since the deformed or collapsed second inorganic particles 13 are densely packed around the first inorganic particles 12, it is possible to prevent the first inorganic particles 12 from being completely compressed in the surface direction. it can. Therefore, the first inorganic particles 12 can effectively increase the thermal conductivity in the thickness direction.

  In the present embodiment, the cured product portion 14 is a portion where the binder resin 11 is cured. The cured product 14 is obtained by curing the binder resin 11. The cured product portion 14 may be a portion where a thermosetting component including a thermosetting compound and a thermosetting agent is cured, or a portion where a photocurable component including a photocurable compound and a photopolymerization initiator is cured. There may be. The hardened | cured material part 14 is obtained by hardening a thermosetting component or a photocurable component.

  The said resin material and the said hardened | cured material can be used for various uses as which heat conductivity, mechanical strength, etc. are calculated | required. For example, in the electronic device, the laminate is used by being disposed between a heat generating component and a heat radiating component. For example, the laminated body is used as a heat radiating body installed between a CPU and fins, or a power card radiating body used in an inverter of an electric vehicle. Further, the laminated body can be used as an insulating circuit substrate by forming a circuit of the conductive layer of the laminated body by a technique such as etching.

  Hereinafter, the present invention will be clarified by giving specific examples and comparative examples of the present invention. The present invention is not limited to the following examples.

Thermosetting compound:
(1) “Epicoat 828US” manufactured by Mitsubishi Chemical Corporation, epoxy compound (2) “DL-92” manufactured by Meiwa Kasei Co., Ltd., phenol novolac compound

Thermosetting agent:
(1) “Dicyandiamide” manufactured by Tokyo Chemical Industry Co., Ltd.
(2) “2MZA-PW” manufactured by Shikoku Kasei Kogyo Co., Ltd., isocyanuric modified solid dispersion type imidazole

First inorganic particles:
(1) “PTX60S” manufactured by Momentive
(2) “PT350” manufactured by Momentive
(3) “CTS7M” manufactured by Saint-Gobain
(4) Inorganic particles 1
(5) Inorganic particles 5
(6) Inorganic particles 6

Second inorganic particles (including alternatives):
(1) Inorganic particles 1
(2) Inorganic particles 2
(3) Inorganic particles 3
(4) Inorganic particles 4
(5) “AC6091” manufactured by Momentive
(6) “CTS7M” manufactured by Saint-Gobain
(7) Inorganic particles 6

Method for producing “inorganic particles 1”:
Boron nitride primary particles having an average major axis of 7.2 μm and an aspect ratio of 5.3 were produced by agglomeration by a spray drying method so that the porosity was 44% and the average particle size was 40 μm. The porosity was measured with a mercury porosimeter, and the porosity when only the voids of 5 μm or less were used as the intraparticle voids was calculated.

  The porosity was measured as follows.

Measuring method of porosity:
Using a mercury porosimeter “pore master 60” manufactured by QUANTACHROME, the cumulative amount of mercury intrusion was measured against the pressure applied by the mercury intrusion method. 0.2 to 0.3 g of boron nitride aggregated particles were weighed and measured in a low pressure mode and a high pressure mode. From the obtained data, a distribution curve indicating the pore volume per unit section of the pore diameter was obtained. Based on the distribution curve, a value (V) obtained by subtracting interparticle voids from all voids was calculated. From the distribution curve, voids having a pore diameter of 5 μm or more were defined as interparticle voids. Using the density of the boron nitride particles (ρ = 2.34) of the primary particles, the porosity (ε) can be expressed by the following equation.

  ε = V (V + (1 / ρ)) × 100

  The porosity was calculated by substituting the obtained value of V into the above formula.

Method for producing “inorganic particles 2”:
Boron nitride primary particles having an average major axis of 6.5 μm and an aspect ratio of 6.1 were produced by agglomeration by a spray drying method so that the porosity was 39% and the average particle size was 30 μm.

Method for producing “inorganic particles 3”:
Boron nitride primary particles having an average major axis of 7.4 μm and an aspect ratio of 5.1 were produced by agglomeration by a spray drying method so that the porosity was 46% and the average particle size was 60 μm.

Method for producing “inorganic particles 4”:
Boron nitride primary particles having an average major axis of 10 μm and an aspect ratio of 6 were prepared by agglomeration by a spray drying method so that the porosity was 25% and the average particle size was 70 μm.

Method for producing “inorganic particles 5”:
Boron nitride primary particles having an average major axis of 7.5 μm and an aspect ratio of 9.8 were produced by agglomeration by a spray drying method so that the porosity was 50% and the average particle size was 110 μm.

Method for producing “inorganic particles 6”:
Boron nitride primary particles having an average major axis of 3.6 μm and an aspect ratio of 13 were produced by agglomeration by a spray drying method so that the porosity was 42% and the average particle size was 40 μm.

(Compressive strength during compression of 10%, 20%, and 30% of each of the first inorganic particles and the second inorganic particles)
The compression strength at the time of compression of 10%, 20%, and 30% of each of the first inorganic particles and the second inorganic particles was measured as follows.

Measuring method of compressive strength at the time of compression of 10%, 20%, and 30% of each of the first inorganic particles and the second inorganic particles:
Using a micro compression tester, a rectangular prism made of diamond was used as a compression member under the condition of a compression speed of 0.67 mN / second, and the smooth end surface of the compression member was lowered toward the inorganic particles to compress the inorganic particles. The first inorganic particles had a maximum test load of 80 mN, and the second inorganic particles had a maximum test load of 40 mN. As a result of the measurement, the relationship between the compression load value and the compression displacement can be obtained. The compression load value per unit area is calculated using the average cross-sectional area calculated using the particle size of the inorganic particles, and this is compressed. Strength. Moreover, the compression rate was calculated from the compression displacement and the particle size of the inorganic particles, and the relationship between the compression strength and the compression rate was obtained. The inorganic particles to be measured were observed using a microscope, and inorganic particles having a particle size of ± 10% were selected and measured. Moreover, the compressive strength in each compression rate was computed as average compressive strength which averaged the measurement result of 20 times. The compression rate was calculated by (compression rate = compression displacement / average particle size × 100).

(Particle diameters of the first inorganic particles and the second inorganic particles)
The particle diameters of the first inorganic particles and the second inorganic particles were measured using a “laser diffraction particle size distribution measuring apparatus” manufactured by Horiba, Ltd. The particle diameters of the first inorganic particles and the second inorganic particles were calculated by sampling each inorganic particle of 3 g and averaging the particle diameters of the inorganic particles contained therein. About the calculation method of an average particle diameter, in each of the 1st inorganic particle and the 2nd inorganic particle, the particle diameter (d50) of an inorganic particle when an accumulation volume is 50% was made into the average particle diameter.

(Aspect ratio of primary particles constituting the first inorganic particles and the second inorganic particles)
The aspect ratio of the primary particles constituting the first inorganic particles and the second inorganic particles was measured as follows.

Method for measuring aspect ratio of primary particles constituting first inorganic particles and second inorganic particles:
Consists of 50 inorganic particles arbitrarily selected from the electron microscopic image of the sheet cross-section prepared by mixing the primary particles constituting the first inorganic particles and the second inorganic particles and the thermosetting resin. The major axis / minor axis of the primary particles to be measured were measured, and the average value was calculated.

(Examples 1-9 and Comparative Examples 1-8)
(1) Preparation of resin material The components shown in Tables 1 and 2 below were blended in the amounts shown in Tables 1 and 2 below, and the resin material was obtained by stirring for 25 minutes at 500 rpm using a planetary stirrer. It was.

(2) Production of Laminate The obtained resin material was applied on a release PET sheet (thickness 50 μm) to a thickness of 350 μm, and dried in an oven at 90 ° C. for 10 minutes to form a curable sheet (insulation) Layer) to form a laminated sheet. Thereafter, the release PET sheet was peeled off, and both surfaces of the curable sheet (insulating layer) were sandwiched between a copper foil and an aluminum plate and vacuum-pressed under the conditions of a temperature of 200 ° C. and a pressure of 12 MPa to prepare a laminate.

(Evaluation)
(1) Thermal conductivity After cutting the obtained laminated body into 1 cm square, the measurement sample was produced by spraying carbon black on both surfaces. Using the obtained measurement sample, thermal conductivity was calculated by a laser flash method. The thermal conductivities in the following Tables 1 and 2 are relative values with the value of Comparative Example 1 being 1.00. For measurement of thermal conductivity, “LFA447” manufactured by NETZSCH was used.

(2) Dielectric breakdown strength By etching the copper foil in the obtained laminate, the copper foil was patterned into a circle having a diameter of 2 cm to obtain a test sample. An AC voltage was applied at 25 ° C. using a withstand voltage tester (“MODEL7473” manufactured by ETECH Electronics) so that the voltage increased at a rate of 0.33 kV / sec between test samples. The voltage at which a current of 10 mA flowed through the test sample was taken as the breakdown voltage. The breakdown voltage was normalized by dividing the breakdown voltage by the thickness of the test sample, and the breakdown strength was calculated. The dielectric breakdown strength was determined according to the following criteria.

[Criteria for dielectric breakdown strength]
○: 60 kV / mm or more Δ: 30 kV / mm or more, less than 60 kV / mm ×: less than 30 kV / mm

(3) Variation in dielectric breakdown strength The obtained laminate was cut into 5 cm squares from different places to obtain 20 measurement samples. In the same manner as (2) above, 20 test samples were prepared, and the dielectric breakdown strength was calculated for each test sample. Variations in dielectric breakdown strength were determined according to the following criteria.

[Criteria for variations in dielectric breakdown strength]
○○: The difference between the maximum value and the minimum value of the dielectric breakdown strength is less than 15 kV / mm ○: The difference between the maximum value and the minimum value of the dielectric breakdown strength is 15 kV / mm or more and less than 20 kV △: The difference between the maximum value and the minimum value is 20 kV / mm or more and less than 40 kV / mm ×: The difference between the maximum value and the minimum value of the dielectric breakdown strength is 40 kV / mm or more

(4) Adhesiveness (peel strength)
The obtained curable sheet (insulating layer 350 μm) was heated at 200 ° C. for 1 hour while being pressed between an electrolytic copper foil (thickness 35 μm) and an aluminum plate (thickness 1 mm) at a pressure of 10 MPa to obtain a measurement sample. It was. Then, the measurement sample was cut out into 5 cm x 12 cm, only the center 1 cm x 12 cm of the short side was left, and the copper foil of the remaining part was peeled off. The peel strength between the center 1 cm electrolytic copper foil and the cured insulating layer was measured by a 90 ° peel test. Adhesiveness (peel strength) was determined according to the following criteria.

[Judgment criteria for adhesiveness (peel strength)]
○: Peel strength is 5 N / cm or more Δ: Peel strength is 2 N / cm or more and less than 5 N / cm X: Peel strength is less than 2 N / cm

  The results are shown in Tables 1 and 2 below.

DESCRIPTION OF SYMBOLS 1 ... Resin sheet 11 ... Binder resin 12 ... 1st inorganic particle 13 ... 2nd inorganic particle 14 ... Hardened | cured material part (part which binder resin hardened | cured)
21 ... laminate 22 ... thermal conductor 22a ... one surface (first surface)
22b ... the other surface (second surface)
23 ... Insulating layer 23a ... One surface (first surface)
23b ... the other surface (second surface)
24 ... conductive layer 24a ... one surface (first surface)
24b ... the other surface (second surface)

Claims (8)

Including first inorganic particles, second inorganic particles, and a binder resin;
The aspect ratio of the primary particles constituting the first inorganic particles is 7 or more,
The aspect ratio of the primary particles constituting the second inorganic particles is less than 7,
A resin material in which a compressive strength at 10% compression of the first inorganic particles and a compressive strength at 10% compression of the second inorganic particles are each 2 N / mm ² or less.   The resin material according to claim 1, wherein the particle diameter of the second inorganic particles is 10 µm or more and 50 µm or less. The compressive strength at the time of 10% compression of the second inorganic particles is 1.5 N / mm ² or less,
The compressive strength at the time of 20% compression of the first inorganic particles and the compressive strength at the time of 20% compression of the second inorganic particles are each 3N / mm ² or less,
The compressive strength at the time of 30% compression of the first inorganic particles and the compressive strength at the time of 30% compression of the second inorganic particles are 4 N / mm ² or less, respectively. The resin material described. The absolute value of the difference between the compressive strength at the time of 20% compression of the first inorganic particles and the compressive strength at the time of 20% compression of the second inorganic particles is 1.5 N / mm ² or less,
The compressive strength at the time of 30% compression of the first inorganic particles is the same as or smaller than the compressive strength at the time of 30% compression of the second inorganic particles. Resin material.   The resin material according to any one of claims 1 to 4, wherein each of the first inorganic particles and the second inorganic particles is boron nitride aggregated particles.   6. The resin material according to claim 1, wherein the total content of the first inorganic particles and the second inorganic particles is 20% by volume or more and 80% by volume or less in 100% by volume of the resin material. The resin material as described in 2.   The resin material according to any one of claims 1 to 6, which is a resin sheet. A heat conductor, an insulating layer laminated on one surface of the heat conductor, and a conductive layer laminated on the surface of the insulating layer opposite to the heat conductor,
The laminated body whose material of the said insulating layer is the resin material of any one of Claims 1-7.

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