JP2017149909A - Heat-conductive adhesive composition, heat-conductive adhesive sheet, and method for producing laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-conductive adhesive composition which reduces an amount of boron nitride particles to be blended and achieves cost reduction, does not lower heat conductivity, adhesiveness and heat resistance when cured, and can be stably held; a heat-conductive adhesive sheet using the same; and a method for producing a laminate.SOLUTION: A heat-conductive adhesive composition contains the following (A), (B1) and (B2) components: (A) 100 pts.wt. of a thermoplastic resin; (B1) 100-450 pts.wt. of boron nitride particles; and (B2) 600-5,000 pts.wt. of metal oxide particles having a number average particle size of 15-200 μm.SELECTED DRAWING: Figure 1

Description

The present invention relates to a heat conductive adhesive composition, a heat conductive adhesive sheet, and a method for producing a laminate.
In particular, while reducing the amount of boron nitride particles to reduce costs, thermal conductivity that can be stably maintained without lowering the thermal conductivity, adhesiveness, and heat resistance when cured. The present invention relates to an adhesive composition, a thermally conductive adhesive sheet using the same, and a method for producing a laminate.

Conventionally, semiconductor integrated circuits are used in various electronic devices.
Among them, in a device that requires a large amount of power, a power module in which power elements such as high-power diodes, transistors, and ICs are mounted is used.
Such a power module is required to have sufficient heat dissipation for releasing heat generated from the power element.
Therefore, a technique of bonding the power module and the heat sink with a heat conductive adhesive sheet is widely used.

As such a heat conductive adhesive sheet and a heat conductive adhesive composition for forming the heat conductive adhesive sheet, various types in which inorganic particles are dispersed in a resin component have been proposed.
Among these, Patent Documents 1 to 3 disclose thermal conductive adhesives that use boron nitride particles and other inorganic oxide particles in combination as inorganic particles.

That is, Patent Document 1 discloses an adhesive composition for electronic equipment containing (a) a thermoplastic resin, (b) an epoxy resin, (c) a curing agent, (d) boron nitride particles, and (e) inorganic spherical particles. And (e) the primary average particle diameter of the inorganic spherical particles is not more than 10 volume% of the primary particle size distribution on the volume basis of the (d) boron nitride particles. Things are disclosed.
As (e) inorganic spherical particles, alumina particles, magnesium oxide particles and the like are described.

Further, Patent Document 2 discloses a first type of heat conduction particles that are consistent in the thermal interface material, and each of the first heat conduction particles itself has a self-binding property of smaller flat particles. A first type of thermally conductive particles that are agglomerated; a second type of thermally conductive particles; a resin particle; and an unstable liquid; up to a range of less than 20% unstable liquid and resin particles Thermal interface materials are disclosed that are soluble in each other.
Further, boron nitride particles are described as the first type of heat conductive particles, and alumina particles, zinc oxide particles, and the like are described as the second type of heat conductive particles.

  Patent Document 3 discloses an adhesive sheet in which a main layer and a skin layer are provided on at least one surface of the main layer, and the main layer is made of a resin containing 75 to 95% by volume of alumina or boron nitride. An adhesive sheet whose layer is made of a resin containing 70 to 80% by volume of alumina is disclosed.

JP 2011-225856 A (Claims etc.) JP 2011-515559 A (Claims etc.) Japanese Patent No. 3514340 (claims, etc.)

However, although the thermally conductive adhesive compositions described in Patent Documents 1 to 3 use boron nitride particles and metal oxide particles such as alumina particles in combination, the amount of boron nitride particles is larger. However, since there are much more than metal oxide particles, the problem that cost reduction cannot fully be realized was observed.
Further, as is clear from the fact that the metal oxide particles used in combination with the boron nitride particles have a small particle size of 10 μm or less, the metal oxide particles have reduced the boron nitride particles as the main particles to the last. It was only used as a sub-particle to fill the minute gap.
Therefore, the combination of the metal oxide particles as the sub-particles is only a deteriorated version of the one using only the boron nitride particles as the main particles, and in fact, it is difficult to obtain sufficient thermal conductivity. The problem was seen.

Accordingly, as a result of studying such problems, the present inventors have determined that metal oxide particles having a predetermined particle size (hereinafter referred to as “large particle size metal oxide”) even when the amount of boron nitride particles is reduced. In other words, it is possible to obtain a cured product having the same characteristics as when only a large amount of boron nitride particles are used. It has been made.
That is, the present invention can reduce the amount of boron nitride particles and reduce the cost, while maintaining stable without reducing the thermal conductivity, adhesiveness and heat resistance when cured. It aims at providing the manufacturing method of the heat conductive adhesive composition which can be performed, a heat conductive adhesive sheet using the same, and a laminated body.

According to this invention, the heat conductive adhesive composition characterized by containing the following (A), (B1), and (B2) component is provided, and the problem mentioned above can be solved.
(A) Thermoplastic resin 100 parts by weight (B1) Boron nitride particles 100 to 450 parts by weight (B2) Metal oxide particles having a number average particle size of 15 to 200 μm 600 to 5000 parts by weight That is, the thermally conductive adhesive of the present invention In the case of a composition, the amount of boron nitride particles is reduced to a predetermined range, and large-sized metal oxide particles are used in a predetermined ratio, so that only a large amount of boron nitride particles is used. As compared with the above, it is possible to stably maintain the cost without lowering the thermal conductivity, adhesiveness and heat resistance when cured, while reducing the cost.

In constituting the thermally conductive adhesive composition of the present invention, the metal oxide particles as the component (B2) are at least one selected from the group consisting of aluminum oxide particles, magnesium oxide particles, and zinc oxide particles. Preferably there is.
By comprising in this way, the hardened | cured material which has a characteristic equivalent to the case where only a large amount of boron nitride particles is used can be obtained more stably.

In constituting the heat conductive adhesive composition of the present invention, the number average particle size of the boron nitride particles as the component (B1) is preferably set to a value in the range of 5 to 200 μm.
By comprising in this way, the heat conductivity and adhesiveness in hardened | cured material can be improved more.

In constituting the thermally conductive adhesive composition of the present invention, the boron nitride particles as the component (B1) are preferably boron nitride particle aggregates.
By comprising in this way, the heat conductivity and adhesiveness in hardened | cured material can be improved further.
In addition, it is preferable that the particle size of the primary particle which comprises a boron nitride particle aggregate is a value within the range of 0.1-100 micrometers.

Moreover, when comprising the heat conductive adhesive composition of this invention, it is preferable that the thermoplastic resin as (A) component is a polyamideimide oligomer.
By comprising in this way, the adhesiveness and heat resistance in hardened | cured material can further be improved.

Moreover, when comprising the heat conductive adhesive composition of this invention, it is preferable to make the number average molecular weight of a polyamideimide oligomer into the value within the range of 1000-15000.
By comprising in this way, the adhesiveness and heat resistance in hardened | cured material can be improved further.

Further, in constituting the thermally conductive adhesive composition of the present invention, as the component (C), as the component (A), a thermal crosslinking agent for crosslinking thermoplastic resins as the component (A), It is preferable to contain in 1-80 weight part with respect to 100 weight part of plastic resins.
By comprising in this way, (A) component can be bridge | crosslinked and a heat conductive adhesive composition can be hardened stably.

Another aspect of the present invention is a thermally conductive adhesive sheet formed from the above-described thermally conductive adhesive composition.
That is, since the heat conductive adhesive sheet of the present invention is formed from a predetermined heat conductive adhesive composition, the cost can be reduced compared with the case where only a large amount of boron nitride particles are used. Although it is intended, it can be stably held without lowering the thermal conductivity, adhesiveness and heat resistance when cured.

Still another embodiment of the present invention is a method for manufacturing a laminate using the above-described heat conductive adhesive sheet, comprising the following steps (a) to (b): It is a manufacturing method.
(A) Step of interposing a heat conductive adhesive sheet between the first structure and the second structure (b) The heat conductive adhesive sheet is pressure-bonded and cured by hot pressing, and the first structure Step of bonding the body and the second structure In other words, in the method for manufacturing a laminate of the present invention, since the predetermined heat conductive adhesive sheet is used, the first method is used even in a high temperature environment. In addition, heat can be efficiently conducted from a relatively high temperature structure to a relatively low temperature structure while stably maintaining the adhesion between the second structure and heat dissipation to the external environment. A laminated body can be manufactured stably and at low cost.

Fig.1 (a)-(c) is a figure provided in order to demonstrate the manufacturing method of the laminated body using the heat conductive adhesive sheet of this invention. FIG. 2 is a diagram provided to show an electron micrograph of a cross section of the thermally conductive adhesive sheet of Example 2. FIGS. 3A to 3B are other views provided for showing an electron micrograph of a cross section of the thermally conductive adhesive sheet of Example 2. FIGS. 4 (a) to 4 (b) are still other views provided for showing an electron micrograph of a cross section of the thermally conductive adhesive sheet of Example 2. FIG. FIGS. 5A to 5B are diagrams provided to illustrate the element distribution in the cross section of the thermally conductive adhesive sheet of Example 2. FIGS. 6 (a) to 6 (b) are other diagrams provided for showing the element distribution in the cross section of the thermally conductive adhesive sheet of Example 2. FIG. FIGS. 7A to 7B are still other views used to show the element distribution in the cross section of the thermally conductive adhesive sheet of Example 2. FIG. FIG. 8 is a diagram provided to show an electron micrograph of a cross section of the cured product of Example 2. FIGS. 9A to 9B are other diagrams provided for showing an electron micrograph of a cross section of the cured product of Example 2. FIG. 10 (a) to 10 (b) are still other diagrams provided for showing an electron micrograph of a cross section of the cured product of Example 2. FIG. FIGS. 11A to 11B are diagrams provided for showing the element distribution in the cross section of the cured product of Example 2. FIGS. 12 (a) to 12 (b) are other diagrams provided for showing the element distribution in the cross section of the cured product of Example 2. FIG. FIGS. 13A to 13B are other diagrams provided for showing the element distribution in the cross section of the cured product of Example 2. FIG.

[First Embodiment]
1st Embodiment is a heat conductive adhesive composition characterized by containing the following (A), (B1), and (B2) component.
(A) Thermoplastic resin 100 parts by weight (B1) Boron nitride particles 100-450 parts by weight (B2) Metal oxide particles having a number average particle size of 15-200 μm 600-5000 parts by weight Hereinafter, heat conduction of the first embodiment The adhesive adhesive composition will be specifically described.

1. (A) component: Thermoplastic resin The heat conductive adhesive composition of this invention is characterized by including a thermoplastic resin as a main ingredient.
This is because a thermoplastic resin can effectively impart functions such as flexibility, thermal stress relaxation, and adhesiveness to the obtained cured product.

(1) Kind Moreover, it does not restrict | limit especially as a kind of thermoplastic resin, For example, acrylonitrile butadiene copolymer, acrylonitrile butadiene styrene resin, polybutadiene, styrene butadiene ethylene resin, acrylic rubber, Examples thereof include polyvinyl butyral, polyamide, polyester, polyimide, polyamideimide, polyurethane and the like.
Among these, polyamide, polyimide, and polyamideimide are more preferable from the viewpoint of heat resistance, and polyamideimide is particularly preferable from the viewpoint of particle dispersibility.
These thermoplastic resins preferably have a functional group capable of reacting with a thermal crosslinking agent as the component (C) described later.
More specifically, it preferably has an epoxy group, a hydroxyl group, a carboxyl group, an amino group, a hydroxyalkyl group, a vinyl group, an isocyanate group, or the like.
Hereinafter, a polyamideimide oligomer that is particularly suitable from the comprehensive viewpoint will be described as an example of the main component of the thermally conductive adhesive composition such as adhesiveness and heat resistance.

(2) Molecular structure Although it does not restrict | limit especially as a molecular structure of this polyamideimide oligomer, It is preferable to have a repeating unit represented by following General formula (1) as a main structural unit.

(In the general formula (1), Ar is at least one selected from the structure represented by the following formula (2), R is at least one selected from the structure represented by the following formula (3), (The repetition number n is a positive number within the range of 2 to 80.)

  Moreover, a polyamide structural unit and a polyimide structural unit may be contained as structural units other than the main structural unit mentioned above.

Further, the polyamideimide oligomer may have a carboxyl group as a crosslinking point at both ends of the molecule as shown in the following general formula (4) or at one end of the molecule as shown in the following general formula (5). preferable.
Thus, by having the carboxyl group used as a crosslinking point in a molecular terminal, the terminal of a polyamide-imide oligomer can be bridge | crosslinked effectively by the thermal crosslinking agent as (C) component mentioned later. As a result, a cured product having excellent thermal conductivity, adhesion and durability can be obtained without substantially using other curing components, and the storage stability of the thermally conductive adhesive composition before curing can be obtained. Can be improved effectively.
That is, a resin excellent in heat resistance can be obtained by cross-linking components having a high glass transition point, which are polyamideimide oligomers, with each other via a thermal cross-linking agent.

(In General Formula (4), Ar is at least one selected from the structure represented by Formula (2), R is at least one selected from the structure represented by Formula (3), and the number of repetitions. n is a positive number in the range of 2-80.)

(In General Formula (5), Ar is at least one selected from the structure represented by Formula (2), R is at least one selected from the structure represented by Formula (3), and the number of repetitions. n is a positive number in the range of 2-80.)

(3) Number average molecular weight Moreover, it is preferable to make the number average molecular weight of a polyamidoimide oligomer into the value within the range of 1000-15000.
The reason for this is that when the number average molecular weight of the polyamideimide oligomer is less than 1000, the heat resistance in the resulting cured product becomes excessively low, and the viscosity of the adhesive composition becomes too low and the shape stability deteriorates. This is because there are cases. On the other hand, when the number average molecular weight of the polyamideimide oligomer exceeds 15000, the component (A) is difficult to dissolve in the solvent, and the coating property of the heat conductive adhesive composition is excessively reduced. This is because it may be difficult to obtain sufficient adhesiveness due to excessive decrease in cross-linking between components.
Therefore, the lower limit of the number average molecular weight of the polyamideimide oligomer is more preferably 2000 or more, further preferably 3000 or more, and particularly preferably 5000 or more.
The upper limit of the number average molecular weight of the polyamideimide oligomer is more preferably 12000 or less, and even more preferably 10,000 or less.

(4) Glass transition point Moreover, it is preferable to make the glass transition point of a polyamide-imide oligomer into the value within the range of 100-300 degreeC.
The reason for this is that when the glass transition point of the polyamideimide oligomer is less than 100 ° C., the heat resistance may be excessively lowered. On the other hand, when the glass transition point of the polyamide-imide oligomer becomes a value exceeding 300 ° C., the adhesive force may be excessively reduced.
Therefore, the lower limit value of the glass transition point of the polyamideimide oligomer is more preferably set to a value of 135 ° C. or higher, and further preferably set to a value of 150 ° C. or higher.
The upper limit value of the glass transition point of the polyamideimide oligomer is more preferably 280 ° C. or less, further preferably 250 ° C. or less, and particularly preferably 220 ° C. or less.

(5) Compounding quantity Moreover, it is preferable to make the compounding quantity of a thermoplastic resin into the value within the range of 1-30 weight% with respect to 100 weight% of solid content of a heat conductive adhesive composition.
The reason for this is that when the blending amount of the thermoplastic resin is less than 1% by weight, crosslinking between the components (A) by the component (C) described later is excessively reduced, and it is difficult to obtain sufficient adhesion. This is because it may be difficult to uniformly disperse and hold the thermally conductive inorganic particles as the component (B) in the conductive adhesive composition. On the other hand, when the blending amount of the thermoplastic resin exceeds 30% by weight, the thermal conductivity may be excessively lowered.
Therefore, the lower limit value of the thermoplastic resin content relative to 100% by weight of the solid content of the thermally conductive adhesive composition is more preferably 3% by weight or more, and more preferably 5% by weight or more. Further preferred.
Further, the upper limit value of the amount of the thermoplastic resin based on 100% by weight of the solid content of the heat conductive adhesive composition is more preferably 20% by weight or less, and further preferably 10% by weight or less. preferable.

2. (B) Component: Thermally conductive inorganic particles The thermally conductive adhesive composition of the present invention comprises (B) a thermally conductive inorganic particle as a component from the viewpoint of imparting thermal conductivity to the adhesive composition. It is characterized by including.
More specifically, at least boron nitride particles as the component (B1) and metal oxide particles as the component (B2) are included.
Hereinafter, each component constituting the component (B) will be specifically described.

(1) Component (B1): Boron Nitride Particles The thermally conductive adhesive composition of the present invention is characterized by containing boron nitride particles as the component (B1).
This is because boron nitride particles can efficiently impart thermal conductivity to the adhesive composition while stably maintaining insulation.
In the case of boron nitride particles, the gap between the large-diameter metal oxide particles as the component (B2) which is the main component (B) is dispersed in the thermoplastic resin as the component (A). It can be filled effectively. Therefore, even with a small amount of blending, a heat transfer network with boron nitride particles can be efficiently constructed, and as a result, the thermal conductivity when cured can be effectively improved.
In other words, the presence of boron nitride particles having high thermal conductivity in the gaps between the large-sized metal oxide particles as the component (B2) allows more efficient transmission than when only large-sized metal oxide particles are included. A thermal network can be constructed.

In addition, from the viewpoint of using a boron nitride particle having a large particle size, a scaly crystal or a boron nitride particle aggregate obtained by secondary aggregation of boron nitride particles having a small particle diameter is preferable.
In particular, it is preferable to use a boron nitride particle aggregate in which boron nitride particles are aggregated.
The reason for this is that if boron nitride particle aggregates are used, it is possible to prevent the boron nitride particles from being oriented in a specific direction (for example, the thickness direction) at the time of coating or curing, thereby reducing the anisotropy in thermal conductivity. This is because expression can be suppressed and heat can be transferred equally in all directions.
The “aggregate” in the present invention is a high-order aggregation of at least 100 primary particles, and is regularly spherical without any orientation (including a perfect sphere, an ellipsoid, a semicircle, and a column). Or the thing which formed polygonal shape is meant.

(1) -1 Particle size The number average particle size of the boron nitride particles is preferably set to a value in the range of 5 to 200 μm.
This is because, when the number average particle diameter of the boron nitride particles is less than 5 μm, it becomes difficult to form a heat transfer network by the boron nitride particles, and the thermal conductivity may be excessively lowered. . On the other hand, when the number average particle size of the boron nitride particles exceeds 200 μm, the adhesion may be excessively lowered due to the exposure of the boron nitride particles to the bonding surface.
Therefore, the lower limit value of the number average particle diameter of the boron nitride particles is more preferably 10 μm or more, further preferably 30 μm or more, and particularly preferably 50 μm or more.
Further, the upper limit of the number average particle diameter of the boron nitride particles is more preferably set to 150 μm or less, and further preferably set to 100 μm or less.
When the boron nitride particles are aggregates of boron nitride particles, the primary particles constituting the aggregates preferably have a particle size of 0.1 to 100 μm, more preferably 1 to 50 μm, and 8 It is particularly preferable that the thickness is about ˜30 μm. In addition, it is not necessary that all primary particles constituting the aggregate have a primary particle size within the above-described range, and it is preferable that 50% or more of the total particles are composed of such particles.
Moreover, although the said primary particle may be spherical or the cross section may be elliptical, the cross section is more preferably elliptical from the viewpoint of easier aggregation.
In the case of primary particles having an elliptical cross section, the major axis is preferably a value within the range of the primary particle diameter described above. On the other hand, the minor axis is preferably 0.05 to 50 μm, more preferably 0.1 to 20 μm, and particularly preferably 0.3 to 5 μm. Further, the aspect ratio of the primary particles is preferably 1.2 to 50, more preferably 3 to 30, and particularly preferably 6 to 15.
In addition, the number average particle diameter in the present invention can be measured by using a laser scattering particle size distribution meter (LA-920, manufactured by Horiba, Ltd.) and dispersing the particles in a medium in which the particles do not swell.

(1) -2 Aspect ratio Moreover, it is preferable to make the aspect ratio of boron nitride particles into a value within the range of 1.1-30.
The reason for this is that when the aspect ratio of the boron nitride particles is less than 1.1, the particles are spherical, so that the contact area between the particles decreases and the thermal conductivity may decrease. On the other hand, when the aspect ratio of the boron nitride particles exceeds 30, the particles are likely to be oriented during coating or curing, and the thermal conductivity in a desired direction may be difficult to express.
Therefore, the lower limit of the aspect ratio of the boron nitride particles is more preferably 1.2 or more, and further preferably 1.3 or more.
The upper limit of the aspect ratio of the boron nitride particles is more preferably 20 or less, further preferably 10 or less, and particularly preferably 5 or less.
The shape of the boron nitride particles having such an aspect ratio is preferably an aggregate or a scale, and particularly preferably an aggregate.

(1) -3 Blending amount Further, the blending amount of boron nitride particles is set to a value within the range of 100 to 450 parts by weight with respect to 100 parts by weight of component (A).
The reason for this is that when the amount of boron nitride particles is less than 100 parts by weight, the effect of filling the gaps of the large-diameter metal oxide particles as the component (B2) is reduced, and the thermal conductivity may decrease. Because there is. On the other hand, when the amount of boron nitride particles exceeds 450 parts by weight, there is no problem in thermal conductivity, but the amount of expensive boron nitride increases, which may increase the cost. is there.
Therefore, the lower limit value of the amount of boron nitride particles added to 100 parts by weight of component (A) is more preferably 125 parts by weight or more, and even more preferably 150 parts by weight or more.
Further, the upper limit value of the amount of boron nitride particles added to 100 parts by weight of component (A) is more preferably 400 parts by weight or less, and even more preferably 350 parts by weight or less.

(2) Component (B2): Large-diameter metal oxide particles The thermally conductive adhesive composition of the present invention is characterized by containing large-diameter metal oxide particles as the (B2) component.
This is because an efficient heat transfer network is formed by reducing the number of heat transfer losses at the contact interface between the particles by blending the large-diameter metal oxide particles. Further, since the volume of the gap between the large-diameter metal oxide particles is large, a large amount of boron nitride particles are contained therein, so that the heat transfer network becomes more efficient.

(2) -1 Type In addition, the type of large-diameter metal oxide particles is not particularly limited, and examples thereof include aluminum oxide particles, magnesium oxide particles, zinc oxide particles, beryllium oxide particles, titanium oxide particles, and the like. Conventionally known ones can be used.
Among these, at least one selected from the group consisting of aluminum oxide particles, magnesium oxide particles, and zinc oxide particles is particularly preferable.
This is because, if these metal oxide particles are used, it is possible to more stably obtain a cured product having the same characteristics as when only a large amount of boron nitride particles are used.
That is, these metal oxide particles have a relatively high thermal conductivity as a single substance, and can easily produce particles having a large particle diameter.

(2) -2 Particle size The number average particle size of the large particle size metal oxide particles is a value within the range of 15 to 200 μm.
The reason for this is that when the number average particle diameter of the large-diameter metal oxide particles is less than 15 μm, the number of contacts between the large-diameter oxide particles increases, and the thermal conductivity may decrease. is there. On the other hand, when the number average particle diameter of the large-diameter metal oxide particles exceeds 200 μm, the adhesion may be excessively lowered due to the exposure of the particles to the bonding surface.
Therefore, the lower limit of the number average particle diameter of the large-diameter metal oxide particles is more preferably 25 μm or more, and even more preferably 35 μm or more.
Further, the upper limit value of the number average particle diameter of the large-sized metal oxide particles is more preferably set to 150 μm or less, and further preferably set to 100 μm or less.
The large-sized metal oxide particles are non-aggregated.

(2) -3 Aspect Ratio The aspect ratio of the large-diameter metal oxide particles is preferably set to a value within the range of 1.1-5.
The reason for this is that when the aspect ratio of the large-diameter metal oxide particles is less than 1.1, the particles become spherical, so that the contact area between the particles decreases and the thermal conductivity may decrease. It is. On the other hand, when the aspect ratio of the large-diameter metal oxide particles exceeds 5, the particles are likely to be oriented during coating or curing, and the thermal conductivity in a desired direction may be difficult to express. Because.
Therefore, the lower limit of the aspect ratio of the large-diameter metal oxide particles is more preferably 1.2 or more, and further preferably 1.3 or more.
The upper limit of the aspect ratio of the large-sized metal oxide particles is more preferably 4.0 or less, and further preferably 3.0 or less.

(2) -4 Blending amount The blending amount of the large-sized metal oxide particles is set to a value in the range of 600 to 5000 parts by weight with respect to 100 parts by weight of the component (A).
The reason for this is that when the blending amount of the large particle size metal oxide particles is less than 600 parts by weight, a heat transfer network is not formed by the large particle size metal oxide particles, and the thermal conductivity may decrease. It is. On the other hand, when the compounding amount of the large-sized metal oxide particles exceeds 5000 parts by weight, the adhesiveness decreases due to the functional inhibition of the resin component or the exposure of the large-sized metal oxide particles to the bonding surface. Because there is.
Therefore, the lower limit value of the compounding amount of the large-sized metal oxide particles with respect to 100 parts by weight of the component (A) is more preferably 700 parts by weight or more, and still more preferably 800 parts by weight or more.
Moreover, it is more preferable to make the upper limit of the compounding quantity of the large-sized metal oxide particles with respect to 100 parts by weight of the component (A) a value of 3000 parts by weight or less, and it is more preferable to set it to a value of 2000 parts by weight or less.

(3) Component (B3): Small Particle Size Metal Oxide Particles The heat conductive adhesive composition of the present invention preferably further contains small particle size metal oxide particles as the component (B3).
This is because the contact area of the metal oxide particles increases due to the inclusion of the small particle size metal oxide particles, and the small particle size metal oxide particles enter between the large particle size metal oxide particles. This is because the conductivity increases.

(3) -1 Type In addition, the type of the small particle size metal oxide particles is not particularly limited, and the above-mentioned types of the large particle size metal oxide particles as the component (B2) are listed. Can be used.

(3) -2 Particle size The number average particle size of the small particle size metal oxide particles is preferably set to a value in the range of 0.1 to 10 μm.
The reason for this is that when the number average particle diameter of the small-sized metal oxide particles is less than 0.1 μm, the number of contact times of the small-sized metal oxide particles increases, so that the effect of increasing the thermal conductivity is obtained. This is because there may not be. On the other hand, when the number average particle diameter of the small-diameter metal oxide particles exceeds 10 μm, it becomes difficult to enter the gaps between the large-diameter metal oxide particles, and the effect of increasing the thermal conductivity is obtained. This is because there may not be.
Therefore, the lower limit of the number average particle diameter of the small-diameter metal oxide particles is more preferably 0.25 μm or more, and further preferably 0.5 μm or more.
The upper limit of the number average particle size of the small-diameter metal oxide particles is more preferably 7 μm or less, and even more preferably 5 μm or less.

(3) -3 Aspect Ratio The aspect ratio of the small-diameter metal oxide particles is preferably set to a value within the range of 1.1-5.
The reason for this is that when the aspect ratio of the small-diameter metal oxide particles is less than 1.1, the particles become spherical, so that the contact area between the particles decreases and the thermal conductivity may decrease. It is. On the other hand, when the aspect ratio of the small-diameter metal oxide particles exceeds 5, it may be difficult to fill the gaps between the large-diameter metal oxide particles.
Therefore, the lower limit of the aspect ratio of the small-diameter metal oxide particles is more preferably 1.2 or more, and further preferably 1.3 or more.
The upper limit of the aspect ratio of the small-diameter metal oxide particles is more preferably 4 or less, and even more preferably 3 or less.

(3) -4 Blending amount The blending amount of the small-diameter metal oxide particles is preferably set to a value in the range of 100 to 1000 parts by weight with respect to 100 parts by weight of the component (A).
The reason for this is that when the amount of the small-sized metal oxide particles is less than 100 parts by weight, it becomes difficult to sufficiently fill the gaps of the large-sized metal oxide particles, and the thermal conductivity increases. This is because the effect may not be obtained. On the other hand, when the amount of the small-sized metal oxide particles exceeds 1000 parts by weight, the small-sized metal oxide particles not only fill the gaps of the large-sized metal oxide particles, Metal oxide particles will independently construct a heat transfer network. For this reason, the contact interface between the small-diameter metal oxide particles increases, and the thermal conductivity may decrease.
Therefore, the lower limit value of the compounding amount of the small-sized metal oxide particles with respect to 100 parts by weight of the component (A) is more preferably 150 parts by weight or more, and further preferably 200 parts by weight or more.
Moreover, it is more preferable to make the upper limit of the compounding quantity of the small-sized metal oxide particles with respect to 100 parts by weight of the component (A) a value of 900 parts by weight or less, and it is more preferable to set the value to 800 parts by weight or less.

(4) Mixing ratio Moreover, it is preferable to make the mixing ratio of (B2) component into the value within the range of 150-1500 weight part with respect to 100 weight part of (B1) component.
The reason for this is that when the blending ratio of the component (B2) becomes a value within the range of less than 150 parts by weight, the blending amount of expensive boron nitride particles increases, and the cost reduction effect may not be obtained. is there. On the other hand, when the blending ratio of the component (B2) exceeds 1500 parts by weight, the blending amount of the large-diameter metal oxide particles increases, and the amount of boron nitride particles filling the gap becomes insufficient. This is because the conductivity may decrease.
Therefore, the lower limit value of the blending ratio of the component (B2) to 100 parts by weight of the component (B1) is more preferably 200 parts by weight or more, and further preferably 300 parts by weight or more.
Further, the upper limit value of the blending ratio of the component (B2) with respect to 100 parts by weight of the component (B1) is more preferably 1250 parts by weight or less, further preferably 1000 parts by weight or less, (B3) Considering the viewpoint of using the components in combination, the value is more preferably 500 parts by weight or less.

Moreover, it is preferable to make the mixture ratio of (B3) component into the value within the range of 100-700 weight part with respect to 100 weight part of (B1) component.
The reason for this is that when the blending ratio of the component (B3) is less than 100 parts by weight, it becomes difficult to sufficiently fill the gaps of the large-diameter metal oxide particles, and the effect of increasing the thermal conductivity is obtained. This is because it may not be possible. On the other hand, when the blending ratio of the component (B3) exceeds 700 parts by weight, not only the small particle size metal oxide particles fill the gaps of the large particle size metal oxide particles but also the small particle size metal oxides. Particles will build their own heat transfer network. For this reason, the contact interface between the small-diameter metal oxide particles increases, and the thermal conductivity may decrease.
Therefore, the lower limit value of the blending ratio of the component (B3) to 100 parts by weight of the component (B1) is more preferably 150 parts by weight or more, and further preferably 200 parts by weight or more.
Further, the upper limit of the blending ratio of the component (B3) to 100 parts by weight of the component (B1) is more preferably 600 parts by weight or less, further preferably 500 parts by weight or less, and 350 parts by weight. The following values are particularly preferable.

3. (C) Component: Thermal crosslinking agent It is preferable that the heat conductive adhesive composition of this invention contains a thermal crosslinking agent as a component for bridge | crosslinking the thermoplastic resins as (A) component.
This is because the component (A) can be crosslinked with substantially no other curing component by selecting an appropriate component (A) if it is a thermal crosslinking agent.
As a result, a cured product excellent in adhesiveness and heat resistance can be easily obtained, while the storage stability of the thermally conductive adhesive composition before curing can be effectively improved.

(1) Kind Moreover, it does not restrict | limit especially as a kind of thermal crosslinking agent, A conventionally well-known thermal crosslinking agent can be used.
For example, a compound such as an isocyanate compound, an epoxy compound, a melamine compound, an aziridine compound, a metal chelate compound, a metal alkoxide, or a metal salt can be used as the thermal crosslinking agent.
These may be used alone or in combination of two or more.

Of the thermal crosslinking agents described above, it is preferable to use a thermal crosslinking agent comprising an epoxy compound (hereinafter referred to as “epoxy thermal crosslinking agent”).
The reason for this is that if it is an epoxy-based thermal crosslinking agent, the gel fraction in the resulting cured product can be increased to obtain excellent heat resistance, while at the time of storage in the composition or for the formation of an adhesive sheet This is because the curing reaction is difficult to proceed during drying.

(2) Molecular weight Moreover, it is preferable to make the molecular weight of a thermal crosslinking agent into the value within the range of 100-500.
The reason for this is that, when the molecular weight of the thermal crosslinking agent is less than 100, the coating property of the heat conductive adhesive composition is not adversely affected, but the heat resistance of the resulting cured product is excessively reduced. Because there is. On the other hand, when the molecular weight of the thermal crosslinking agent exceeds 500, it usually becomes a solid at room temperature, so that the coating property of the thermally conductive adhesive composition is adversely affected or the crosslinking becomes insufficient. This is because the gel fraction may decrease and the adhesiveness may decrease excessively.
Therefore, the lower limit of the molecular weight of the thermal crosslinking agent is more preferably 150 or more, and even more preferably 200 or more.
Further, the upper limit value of the molecular weight of the thermal crosslinking agent is more preferably set to 450 or less, and further preferably set to 400 or less.

  Examples of such epoxy-based thermal crosslinking agents include 2,2- [isopropylidenebis [4,1-phenylene (oxymethylene)]] bisoxirane (molecular weight 340, liquid at room temperature), 2,2- [Methylenebis (2,1-phenyleneoxymethylene)] bisoxirane (molecular weight 312, liquid at room temperature) and the like are preferably used.

(3) Compounding quantity Moreover, it is preferable to make the compounding quantity of a thermal crosslinking agent into the value within the range of 1-80 weight part with respect to 100 weight part of (A) component.
The reason for this is that when the blending amount of the thermal crosslinking agent is less than 1 part by weight, the curing reaction does not proceed sufficiently and the adhesiveness may be excessively lowered. On the other hand, when the blending amount of the thermal crosslinking agent exceeds 80 parts by weight, unreacted crosslinking agent remains, and thermal conductivity, adhesiveness, and heat resistance may all be excessively reduced. .
Therefore, the lower limit of the amount of the thermal crosslinking agent relative to 100 parts by weight of component (A) is more preferably 3 parts by weight or more, further preferably 5 parts by weight or more, and 20 parts by weight or more. It is particularly preferable that
Moreover, it is more preferable to make the upper limit of the compounding quantity of the thermal crosslinking agent with respect to 100 weight part of (A) component into 70 weight part or less, and it is further more preferable to set it as 60 weight part or less.

4). (D) component: Organic solvent Moreover, it is preferable that the heat conductive adhesive composition of this invention contains the organic solvent.
The reason for this is that by including an organic solvent, the viscosity of the heat conductive adhesive composition can be adjusted to an appropriate range and the coating property can be improved.

(1) Kind In addition, the kind of the organic solvent is not particularly limited, and a conventionally known organic solvent can be used. For example, acetone, methyl ethyl ketone, cyclohexanone, methylcyclohexanone, isophorone, N-methyl- Examples include 2-pyrrolidone, N, N-diethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, γ-butyrolactone, hexamethylphosphoamide, 1,3-dimethyl-2-imidazolidinone.
In particular, it is more preferable to use at least one selected from the group consisting of cyclohexanone, methylcyclohexanone, methyl ethyl ketone, acetone, and isophorone from the viewpoint of compatibility with the thermoplastic resin and ease of evaporation during drying.

(2) Compounding quantity Moreover, it is preferable to set it as the value within the range of 100-1500 weight part with respect to 100 weight part of (A) component as a compounding quantity of an organic solvent.
This is because when the blending amount of the organic solvent is less than 100 parts by weight, the viscosity of the coating liquid becomes high and coating may be difficult. On the other hand, when the amount of the organic solvent exceeds 1500 parts by weight, the solvent does not evaporate during drying and remains in the sheet, which may reduce the dielectric breakdown voltage.
Therefore, the lower limit value of the amount of the organic solvent added relative to 100 parts by weight of component (A) is more preferably 150 parts by weight or more, and even more preferably 200 parts by weight or more.
Moreover, it is more preferable to make the upper limit of the compounding quantity of the organic solvent with respect to 100 weight part of (A) component into the value of 1200 weight part or less, and it is further more preferable to set it as the value of 1000 weight part or less.

5. Other additives In addition to the components (A) to (D) described above, the thermally conductive adhesive composition of the present invention may contain other additives such as a silane coupling agent, It is preferable that the curing component is not substantially blended.
The reason for this is that the storage stability of the thermally conductive adhesive composition may be easily lowered when a curing component is further blended in addition to the components (A) to (D).
As such a curing component, for example, when an epoxy thermal crosslinking agent is used as the component (C), diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide as the curing agent. , Polyamide resin synthesized from dimer of linolenic acid and ethylenediamine, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, mentioned amine complex, guanidine derivatives, and - hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, a polyhydric phenol compound such as phenol novolak, triphenylmethane and their modified products, imidazole, BF ₃ It is.

  Also, for example, imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, 1,8-diaza-bicyclo (5,4,0) It is preferable that substantially no curing catalyst such as tertiary amines such as undecene-7, phosphines such as triphenylphosphine, and metal compounds such as tin octylate is substantially blended.

  In addition to the components (A) to (D), when a curing component is further blended, the value is preferably 10 parts by weight or less with respect to 100 parts by weight of the component (A). The following value is more preferable, and a value of 1 part by weight or less is further preferable.

[Second Embodiment]
The second embodiment is a heat conductive adhesive sheet formed from the heat conductive adhesive composition of the first embodiment.
With such a heat conductive adhesive sheet, since it is formed from a predetermined heat conductive adhesive composition, while achieving cost reduction compared to the case where only a large amount of boron nitride particles is used, It can be stably held without lowering the thermal conductivity, adhesiveness and heat resistance when cured.
Hereinafter, the heat conductive adhesive sheet of 2nd Embodiment is demonstrated concretely.

1. Manufacturing method The heat conductive adhesive sheet of this invention is formed from the heat conductive adhesive composition of 1st Embodiment, It is characterized by the above-mentioned.
More specifically, for a release film such as a polyethylene terephthalate film subjected to silicone release treatment, a spin coater, spray coater, bar coater, knife coater, roll coater, knife roll coater, blade coater, gravure coater, curtain The heat conductive adhesive composition is applied using a coater, a die coater or the like.
Then, it can be dried at 70 to 140 ° C. for 1 to 30 minutes to obtain a heat conductive adhesive sheet.
In addition, it is preferable to bond a peeling film also to this exposed surface from a viewpoint of protecting the exposed surface of the obtained heat conductive adhesive sheet.

2. Thickness Moreover, it is preferable to make the thickness of a heat conductive adhesive sheet into the value within the range of 50-800 micrometers.
This is because when the thickness of the thermally conductive adhesive sheet is less than 50 μm, sufficient insulation cannot be secured, or the thickness of the sheet becomes thinner than the thermally conductive inorganic particles. This is because the particles may be exposed on the sheet surface and the adhesiveness may be excessively lowered. On the other hand, when the thickness of the thermally conductive adhesive sheet exceeds 800 μm, the solvent does not completely evaporate during drying and remains in the sheet, which may reduce the dielectric breakdown voltage.
Therefore, the lower limit value of the thickness of the heat conductive adhesive sheet is more preferably 60 μm or more, and even more preferably 70 μm or more.
The upper limit value of the thickness of the heat conductive adhesive sheet is more preferably 700 μm or less, further preferably 600 μm or less, and particularly preferably 300 μm or less.

3. Gel fraction Moreover, it is preferable to make the gel fraction of a heat conductive adhesive sheet into the value of 10% or less.
The reason for this is that when the gel fraction of the thermally conductive adhesive sheet exceeds 10%, there is a possibility that the storage stability until it is used for adhesion between members by hot pressing is too low. Because.
Therefore, the gel fraction of the heat conductive adhesive sheet is more preferably 8% or less, and further preferably 5% or less.

[Third Embodiment]
3rd Embodiment is a manufacturing method of the laminated body using the heat conductive adhesive sheet of 2nd Embodiment, Comprising: The laminated body characterized by including the following process (a)-(b) It is a manufacturing method.
(A) Step of interposing a heat conductive adhesive sheet between the first structure and the second structure (b) The heat conductive adhesive sheet is pressure-bonded and cured by hot pressing, and the first structure The process of adhering the body and the second structure The manufacturing method of such a laminated body uses the predetermined heat conductive adhesive sheet, so that the first and second structures can be used even in a high temperature environment. While maintaining stable adhesion between structures, heat can be efficiently conducted from a relatively high temperature structure to a relatively low temperature structure, and a laminate that can dissipate heat to the external environment is stable. And can be manufactured at low cost.
Hereinafter, the manufacturing method of the laminated body of 3rd Embodiment is demonstrated concretely.

1. Step (a)
In the step (a), as shown in FIG. 1A, the thermally conductive adhesive sheet 1 of the second embodiment is interposed between the first structure 20 and the second structure 30. It is.
Here, the first structure 20 and the second structure 30 are not particularly limited as long as they are used in combination that requires one heat to be conducted to the other.
For example, as shown in FIG. 1C, when the first structure 20 is a power module and the second structure 30 is a heat sink, the heat generated from the power module is transferred to the heat conductive adhesive sheet 1. It can be efficiently conducted to the heat sink through the cured product 10 and can be radiated to the external environment.
Other combinations of the first structure 20 and the second structure 30 include a combination of a semiconductor circuit and a heat dissipation board or an LED heat sink, or a combination of a battery for a portable device and a housing.

2. Step (b)
In the step (B), as shown in FIG. 1B, the heat conductive adhesive sheet 1 is pressure-bonded and cured by hot pressing (200a, 200b), and the first structure 20 and the second structure 30 are bonded. Are bonded to each other, and as shown in FIG. 1 (c), a laminated body 100 composed of the first structure 20 / cured product 10 / second structure 30 is obtained.
The conditions for the hot press at this time are a press temperature within a range of 150 to 250 ° C., a press pressure within a range of 150 to 600 kgf / cm ² , and a press time within a range of 3 to 60 minutes. It is preferable to set the value of.
Moreover, since the thickness of the hardened | cured material 10 becomes thinner than the heat conductive adhesive sheet before performing a hot press, it is preferable to set it as the value within the range of 40-500 micrometers.

3. Gel fraction of cured product It is preferable to make the gel fraction of the cured product a value in the range of 50 to 100%.
This is because when the gel fraction of the cured product is less than 50%, the adhesiveness and heat resistance may be excessively lowered.
Therefore, the lower limit value of the gel fraction of the cured product is more preferably 60% or more, and further preferably 70% or more.
In addition, about the measurement conditions of the gel fraction of hardened | cured material, it describes in an Example.

4). Further, it is preferable to set the thermal conductivity of the cured product to a value within the range of 8 to 200 W / m · K.
The reason for this is that when the thermal conductivity of the cured product is less than 8 W / m · K, the thermal conductivity directly decreases, and it may be difficult to obtain a desired heat dissipation effect. . On the other hand, when the heat conductivity of the cured product exceeds 200 W / m · K, the content of the heat conductive inorganic particles increases and the adhesive strength may be excessively reduced.
Therefore, the lower limit value of the thermal conductivity of the cured product is more preferably 10 W / m · K or more, and further preferably 12 W / m · K or more.
The upper limit value of the thermal conductivity of the cured product is more preferably 150 W / m · K or less, more preferably 100 W / m · K or less, and a value of 20 W / m · K or less. It is particularly preferable that
In addition, about the measurement conditions of the heat conductivity of hardened | cured material, it describes in an Example.
In the present invention, “W / m · K” means “W / (m · K)”.

5. Adhesive strength of the cured product The adhesive strength of the cured product in a 23 ° C. environment is preferably set to a value in the range of 3 to 50 N / 25 mm.
This is because the first structure and the second structure may be peeled when used as a laminate when the adhesive strength of the cured product at 23 ° C. is less than 3 N / 25 mm. It is. On the other hand, when the adhesive strength of the cured product in a 23 ° C. environment exceeds 50 N / 25 mm, it is difficult to disassemble the first structure and the second structure after the use of the laminate is finished. This is because it may become.
Therefore, the lower limit value of the adhesive strength of the cured product in a 23 ° C. environment is more preferably 4.5 N / 25 mm or more, and further preferably 6 N / 25 mm or more.
Further, the upper limit value of the adhesive strength of the cured product in a 23 ° C. environment is preferably set to a value of 40 N / 25 mm or less, more preferably set to a value of 30 N / 25 mm or less, and a value of 18 N / 25 mm or less. It is particularly preferred.
In addition, about the measurement conditions of the adhesive force in 23 degreeC environment of hardened | cured material, it describes in an Example.

Moreover, it is preferable to make the adhesive force in 150 degreeC environment of hardened | cured material into the value within the range of 1-40N / 25mm.
The reason for this is that when the adhesive strength of the cured product at 150 ° C. is less than 1 N / 25 mm, the first structure and the second structure can be obtained when the laminate is placed in a high temperature environment. This is because may peel off. On the other hand, when the adhesive strength of the cured product at 150 ° C. exceeds 40 N / 25 mm, the first structure and the second structure may be decomposed when the use of the laminate is finished. This is because it may be difficult.
Accordingly, the lower limit value of the adhesive strength of the cured product in an environment of 150 ° C. is more preferably 1.5 N / 25 mm or more, and further preferably 2 N / 25 mm or more.
The upper limit value of the adhesive strength of the cured product in an environment at 150 ° C. is more preferably 30 N / 25 mm or less, further preferably 20 N / 25 mm or less, and 10 N / 25 mm or less. Particularly preferred.
In addition, about the measurement conditions of the adhesive force in 150 degreeC environment of hardened | cured material, it describes in an Example.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to these descriptions.

[Example 1]
1. Preparation of Thermally Conductive Adhesive Composition As shown in Table 1 and below, thermoplastic resin as component (A), boron nitride particles as component (B1), and metal oxide particles as component (B2) And the thermal crosslinking agent as (C) component and the organic solvent as (D) component were mixed, and the heat conductive adhesive composition was prepared.
In addition, the compounding quantity in Table 1 and the following shows the value converted into solid content except (D) component and liquid (C) component. In addition, (C) component and (D) component show the value converted into pure part.

(A) Component: Polyamideimide oligomer 100 parts by weight (manufactured by Toyobo Co., Ltd., ACX-02, number average molecular weight: 8000, glass transition point: 190 ° C., having carboxyl groups at both ends)
Component (B1): 230 parts by weight of boron nitride particle aggregate (manufactured by Showa Denko KK, UHP-G1F, number average particle size: 80 μm, aspect ratio: 1.5)
Component (B2): 1350 parts by weight of round aluminum oxide particles (AS-10, manufactured by Showa Denko KK, number average particle size: 50 μm, aspect ratio: 1.5)
(C) Component: 40 parts by weight of epoxy resin (2,2 ′-[isopropylidenebis [4,1-phenylene (oxymethylene)]] bisoxirane (the following formula (6), molecular weight 340, liquid)
(D) Component: 1000 parts by weight of cyclohexanone In addition, in the following, the component (B2) described above may be referred to as “large-diameter aluminum oxide particles A”.
Regarding the component (B1), according to observation with an electron microscope, the primary particles of the aggregate had an elliptical cross section, a major axis particle size of about 10 μm, and an aspect ratio of about 10.

2. Production of Thermally Conductive Adhesive Sheet Next, the obtained thermally conductive adhesive composition was a polyethylene terephthalate film (manufactured by Lintec Corporation, SP-PET751031) subjected to silicone release treatment (hereinafter referred to as “PET”). )) And dried at 120 ° C. for 3 minutes to obtain a heat conductive adhesive sheet having a thickness of 150 μm.

3. Evaluation (1) Coating property The coating property of the thermally conductive adhesive composition when producing the thermally conductive adhesive sheet was visually evaluated according to the following criteria. The obtained results are shown in Table 1.
○: The surface of the obtained heat conductive adhesive sheet is uniform. Δ: The surface of the obtained heat conductive adhesive sheet is cracked. ×: The heat conductive adhesive composition is non-uniform. And cannot be applied

(2) Gel fraction The curability of the heat conductive adhesive sheet was evaluated by the gel fraction (%).
That is, first, an adhesive composition for gel fraction measurement having a composition in which only the heat conductive inorganic particles such as the components (B1) and (B2) were removed from the obtained heat conductive adhesive composition was prepared.
Next, the obtained adhesive composition for measuring a gel fraction was applied to a release-treated surface of PET and dried at 120 ° C. for 3 minutes to obtain a 150 μm thick adhesive sheet for measuring a gel fraction.
Subsequently, another PET is laminated so that the peeled surface is in contact with the exposed surface of the obtained adhesive sheet for measuring gel fraction, and the adhesive sheet for measuring gel fraction in a state where both surfaces are sandwiched by PET. Got.
Next, the gel sheet for measuring the gel fraction in a state where both surfaces are sandwiched between PET is hot-pressed under the conditions of 180 ° C., 500 kgf / cm ² , 30 minutes, It was set as the hardened | cured material for a gel fraction measurement.
Next, the obtained cured product for gel fraction measurement is wrapped in a polyester mesh having a mesh size of 200, immersed in a sufficient amount of cyclohexanone at room temperature for 48 hours, and the gel fraction (%) is determined from the weight measured before and after immersion. Calculated. The obtained results are shown in Table 1.

(3) Thermal conductivity The thermal conductivity (W / m · K) when the obtained thermally conductive adhesive sheet was cured was evaluated.
That is, another PET was laminated so that the release-treated surface was in contact with the exposed surface of the obtained heat conductive adhesive sheet, and a heat conductive adhesive sheet in which both surfaces were sandwiched between PET was obtained.
Next, the heat conductive adhesive sheet in which both sides are sandwiched between PET is subjected to hot pressing under conditions of 180 ° C., 500 kgf / cm ² , 30 minutes, and the heat conductive adhesive sheet is cured and cured. It was a thing. At this time, the thickness of the obtained cured product was 100 μm.
Next, after peeling the PET on both sides, the thermal conductivity (W / m · K) of the cured product was measured using a thin film thermal diffusion / thermal conductivity measuring device (ai-Phase Mobile 1u, manufactured by Eye Phase Co., Ltd.). And measured by the temperature wave method (TWA). The obtained results are shown in Table 1.

(4) Adhesive strength The adhesive strength (N / 25 mm) when the obtained heat conductive adhesive sheet was cured was measured.
That is, PET is peeled from the obtained heat conductive adhesive sheet, and electrolytic copper foil (Fukuda Metal Foil Powder Co., Ltd., CF-T8G-UN 35) is applied to both sides of the heat conductive adhesive sheet. Lamination was performed so that the glossy surfaces were in contact with each other, and a heat conductive adhesive sheet in a state where both surfaces were sandwiched between electrolytic copper foils was obtained.
Next, the heat conductive adhesive sheet with both surfaces sandwiched between the electrolytic copper foils is subjected to hot pressing under conditions of 180 ° C., 500 kgf / cm ² and 30 minutes to cure the heat conductive adhesive sheet. To obtain a cured product. At this time, the thickness of the obtained cured product was 100 μm.
Next, the cured product is cut into a width of 25 mm together with the electrolytic copper foils on both sides, and then one electrolytic copper foil is chucked (fixed) and a tensile tester (Orientec Co., Ltd. Tensilon Universal Tensile Tester) is used. Then, the film was peeled off under conditions of a peeling angle of 180 °, a peeling speed of 300 mm / min, and a 23 ° C. environment, and the adhesive strength (N / 25 mm) was measured.
Moreover, the adhesive force (N / 25 mm) was similarly measured under an environment of 150 ° C. The obtained results are shown in Table 1.

[Example 2]
In Example 2, the component (B2) in the thermally conductive adhesive composition was made of round aluminum oxide particles (AS-20, number average particle diameter: 40 μm, aspect ratio: 1.5, manufactured by Showa Denko KK). In addition, 810 parts by weight of this was blended, and as the component (B3), round aluminum oxide particles (manufactured by Showa Denko KK, AL-47-H, number average particle size: 2 μm, aspect ratio: 1.5) ), And a heat conductive adhesive composition and a heat conductive adhesive sheet were produced and evaluated in the same manner as in Example 1. The obtained results are shown in Table 1.
In the following, the component (B2) described above may be referred to as “large particle size aluminum oxide particles B” and the component (B3) may be referred to as “small particle size aluminum oxide particles a”.

Moreover, the electron micrograph in the cross section of the obtained heat conductive adhesive sheet is shown in FIG.
This cross section is obtained by cutting the obtained heat conductive adhesive sheet in the thickness direction with a cross section polisher and observing the cut surface with a scanning electron microscope (SEM).
Moreover, the enlarged photograph of the upper part, intermediate | middle part, lower part in FIG. 2, and the part between metal oxide particles is shown to Fig.3 (a), FIG.3 (b), FIG.4 (a), and FIG.4 (b), respectively.
In addition, element distribution (boron (B), carbon (C), nitrogen (N), oxygen (O), and aluminum (Al) in the cross section of the thermally conductive adhesive sheet shown in FIG. b), FIG. 6 (a), FIG. 6 (b), FIG. 7 (a) and FIG. 7 (b).
2-7, it was confirmed that the boron nitride particles and the small-sized metal oxide particles are filled in the gaps of the large-sized metal oxide particles.
Therefore, it is understood that an efficient heat transfer network is obtained by filling the gaps between the large-sized metal oxide particles with boron nitride particles having high thermal conductivity.

Moreover, the electron micrograph in the cross section of the obtained hardened | cured material is shown in FIG.
Moreover, the enlarged photograph of the upper part, intermediate | middle part, lower part in FIG. 8, and the part between metal oxide particles is shown to Fig.9 (a), FIG.9 (b), FIG.10 (a), and FIG.10 (b), respectively.
Moreover, element distribution (boron (B), carbon (C), nitrogen (N), oxygen (O), and aluminum (Al) in the cross section of the heat conductive adhesive sheet shown in FIG. b), FIG. 12 (a), FIG. 12 (b), FIG. 13 (a) and FIG. 13 (b).
From FIGS. 9-14, it was confirmed that the space | gap seen by the cross-sectional photograph of the heat conductive adhesive sheet is lose | eliminated.
Therefore, it is understood that the thermal conductivity is increased because the particles are more closely packed and the contact area is increased.

[Example 3]
In Example 3, the component (B2) in the thermally conductive adhesive composition was changed to magnesium oxide particles (manufactured by Ube Industries, RF-98, number average particle size: 50 μm, aspect ratio: 1.5). A heat conductive adhesive composition and a heat conductive adhesive sheet were produced and evaluated in the same manner as in Example 1 except that 1250 parts by weight of this was blended. The obtained results are shown in Table 1.
Hereinafter, the component (B2) described above may be referred to as “large-diameter magnesium oxide particles”.

[Example 4]
In Example 4, the component (B1) in the thermally conductive adhesive composition was changed to scaly boron nitride particles (manufactured by Showa Denko KK, UHP-2, number average particle size: 10 μm, aspect ratio: 30). , 230 parts by weight of this, and the component (B2) is changed to the large-diameter aluminum oxide particles B, 810 parts by weight of this, and further, the component (B3) is 540 parts by weight of the small-diameter aluminum oxide particles a. A heat conductive adhesive composition and a heat conductive adhesive sheet were produced and evaluated in the same manner as in Example 1 except that the components were mixed. The obtained results are shown in Table 1.

[Example 5]
In Example 5, the blending amount of the component (B1) in the heat conductive adhesive composition was changed to 150 parts by weight, and the component (B2) was changed to the large-diameter aluminum oxide particles B, which was blended by 900 parts by weight. Further, a heat conductive adhesive composition and a heat conductive adhesive sheet were produced and evaluated in the same manner as in Example 1 except that 600 parts by weight of the small-diameter aluminum oxide particles a were blended as the component (B3). did. The obtained results are shown in Table 1.

[Comparative Example 1]
In Comparative Example 1, the component (B2) in the heat conductive adhesive composition was not blended, and as the component (B3), spherical aluminum oxide particles (manufactured by Showa Denko KK, CB-P05, number average particle size: 5 μm) The aspect ratio was changed to 1.0), and a heat conductive adhesive composition and a heat conductive adhesive sheet were produced and evaluated in the same manner as in Example 1 except that 1350 parts by weight of this was blended. The obtained results are shown in Table 1.
Hereinafter, the component (B3) described above may be referred to as “small-diameter aluminum oxide particles b”.

[Comparative Example 2]
In Comparative Example 2, the components (B1) and (B2) in the heat conductive adhesive composition were not blended, and as the component (B3), 1700 parts by weight of the small-diameter aluminum oxide particles b were blended. 1 and the heat conductive adhesive composition and the heat conductive adhesive sheet were manufactured and evaluated. The obtained results are shown in Table 1.

[Comparative Example 3]
In Comparative Example 3, the component (B1) in the thermally conductive adhesive composition was not blended, the component (B2) was replaced with large-sized magnesium oxide particles, and 1250 parts by weight of this was blended in Example 1. In the same manner, a heat conductive adhesive composition and a heat conductive adhesive sheet were produced and evaluated. The obtained results are shown in Table 1.

[Reference Example 4]
In Reference Example 4, Example 1 except that the blending amount of the component (B1) in the thermally conductive adhesive composition in the thermally conductive adhesive composition was changed to 485 parts by weight and the component (B2) was not blended. In the same manner, a heat conductive adhesive composition and a heat conductive adhesive sheet were produced and evaluated. The obtained results are shown in Table 1.

As described above in detail, according to the thermally conductive adhesive composition of the present invention, even when the blending amount of boron nitride particles is reduced, the metal oxide particles having a predetermined particle diameter are in a predetermined ratio. By using in combination, it becomes possible to obtain a cured product having the same characteristics as when only a large amount of boron nitride particles are used.
As a result, while reducing the amount of boron nitride particles to reduce costs, it can be held stably without reducing the thermal conductivity, adhesiveness and heat resistance when cured. became.
Therefore, the heat conductive adhesive composition of the present invention contributes significantly to the cost reduction in a high performance heat conductive adhesive composition used for heat dissipation of electronic parts such as power modules. It is expected.

1: thermally conductive adhesive sheet, 10: cured product, 20: first structure, 30: second structure, 100: laminate

Claims (9)

A heat conductive adhesive composition comprising the following components (A), (B1) and (B2):
(A) Thermoplastic resin 100 parts by weight (B1) Boron nitride particles 100 to 450 parts by weight (B2) Metal oxide particles having a number average particle diameter of 15 to 200 μm 600 to 5000 parts by weight   2. The heat conductive adhesive according to claim 1, wherein the metal oxide particles as the component (B2) are at least one selected from the group consisting of aluminum oxide particles, magnesium oxide particles, and zinc oxide particles. Composition.   The heat conductive adhesive composition according to claim 1 or 2, wherein the number average particle diameter of the boron nitride particles as the component (B1) is set to a value in the range of 5 to 200 µm.   The thermally conductive adhesive composition according to any one of claims 1 to 3, wherein the boron nitride particles as the component (B1) are boron nitride particle aggregates.   The heat conductive adhesive composition according to any one of claims 1 to 4, wherein the thermoplastic resin as the component (A) is a polyamideimide oligomer.   The heat conductive adhesive composition according to claim 5, wherein the polyamideimide oligomer has a number average molecular weight in a range of 1000 to 15000.   As the component (C), a thermal crosslinking agent for crosslinking the thermoplastic resins as the component (A) is in the range of 1 to 80 parts by weight with respect to 100 parts by weight of the thermoplastic resin as the component (A). The heat conductive adhesive composition according to any one of claims 1 to 6, wherein the heat conductive adhesive composition is included in the heat conductive adhesive composition.   The heat conductive adhesive sheet formed from the heat conductive adhesive composition as described in any one of the said Claims 1-7. It is a manufacturing method of a layered product using the heat conductive adhesive sheet according to claim 8,
The manufacturing method of the laminated body characterized by including the following process (a)-(b).
(A) a step of interposing the thermally conductive adhesive sheet between the first structure and the second structure (b) the thermal conductive adhesive sheet is pressure-bonded and cured by hot pressing; The process of bonding the structure of 1 and the second structure