JP2019172935A - 2-component type thermal conductive resin composition, thermal conductive sheet, metal product and electronic equipment - Google Patents

Abstract

To obtain a composition capable of forming a thermal conductive sheet not containing a solvent, and excellent in thermal conductivity in a thickness direction and adhesiveness.SOLUTION: A 2-component type thermal conductive resin composition comprises a first component containing a liquid polyol (I) and an inorganic filler which is an aggregate (III) of scale-like particles of boron nitride; and a second component containing polyisocyanate (II). A thermal conductive sheet formed of the 2-component type thermal conductive resin composition is excellent in thermal conductivity not only in a surface direction but also in a thickness direction, and further has excellent adhesiveness.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a two-component heat conductive resin composition. In particular, the present invention relates to a two-component heat conductive resin composition capable of forming a heat conductive member having excellent heat conductivity and adhesiveness in the thickness direction.

2. Description of the Related Art A heat sink is known as a component that is attached to a mechanical / electrical component that generates heat and aims to lower the temperature by radiating heat. In many cases, heat sinks are mainly made of metal such as aluminum or copper, which easily conducts heat.
As a general method of heat dissipation, a heat conductive sheet made of resin is sandwiched between a heating element such as a semiconductor package and a heat sink made of aluminum or copper, and the heating element and the heat sink are brought into close contact with each other. There is a method of dissipating heat by efficiently transferring heat to a heat sink.

  As a composition capable of forming such a heat conductive sheet, Patent Document 1 discloses polyurethane water-dispersed particles, aggregates in which hexagonal nitride crystals are aggregated, polyurethane water-dispersed particles, and aggregates. A resin composition for a heat conductive sheet containing water in which is dispersed is disclosed. This composition is easy to handle because the dispersion medium is water (or an aqueous liquid, etc.), and can be solidified by applying and drying (removing moisture) to easily form a heat conductive sheet. (Claim 1, paragraph 0019).

International Publication No. 2015/105106

However, since the resin composition for a heat conductive sheet contains a solvent, a step of evaporating the solvent is required when forming the sheet. In the market, it is desired that a sheet can be formed more easily. For example, even if it is relatively easy to dry at normal temperature or heat, it is desired that there is no evaporation step itself.
Then, this invention makes it a subject to provide the composition which does not contain a solvent and can form the heat conductive sheet excellent in the heat conductivity and adhesiveness of the thickness direction.

  The present inventor has intensively studied to solve the above problems. As a result, combining liquid polyol and boron nitride scaly particle aggregates and polyisocyanate provides excellent thermal conductivity in the thickness direction from a composition that does not require a solvent, and further excellent thermal conductivity. The present inventors have found that a sheet can be formed and completed the present invention.

The two-component heat conductive resin composition according to the first aspect of the present invention includes a first component containing an inorganic filler that is an aggregate (III) of liquid polyol (I) and boron nitride scaly particles; And a second component containing isocyanate (II). “Agglomerate” is typically a state in which primary particles are aggregated, and a plurality of primary particles are aggregated into a lump. “Agglomerates of scaly particles of boron nitride” refer to particles in a state where scaly particles of primary boron nitride particles are aggregated. The shape of the aggregate is not particularly limited, and may be, for example, a rounded snowman, spherical, substantially spherical, oblate, or a shape like a rugby ball. Other shapes such as chocolate flakes, desert roses (mineral crystals), and worm-like nests may also be used.
If comprised in this way, the solventless composition which can form the heat conductive sheet excellent in the heat conductivity and adhesiveness of the thickness direction can be obtained. Furthermore, the two-component heat conductive resin composition is easy to handle because it has good flowability after curing after mixing and can be cured at low temperature. In the present specification, the “solvent” is a component of the composition and requires an evaporation step (or drying step).

The two-component heat conductive resin composition according to the second aspect of the present invention is the two-component heat conductive resin composition according to the first aspect of the present invention, wherein the polyol (I) is at least one kind. Contains polycarbonate polyol.
If comprised in this way, it will become a composition which can form the heat conductive sheet whose characteristic of polyurethane was more excellent.

The two-component thermal conductive resin composition according to the third aspect of the present invention is the two-component thermal conductive resin composition according to the second aspect of the present invention, wherein the polyol (I) is at least one kind. Contains polycarbonate diol.
If comprised in this way, it will become a composition which can form the heat conductive sheet in which the characteristic of polyurethane was especially excellent.

The two-component thermal conductive resin composition according to the fourth aspect of the present invention is the two-component thermal conductive resin composition according to any one of the first to third aspects of the present invention, The polyisocyanate (II) contains at least one non-yellowing polyisocyanate.
If comprised in this way, the formed heat conductive sheet can suppress yellowing by an ultraviolet-ray or a heat | fever.

The two-component heat conductive resin composition according to the fifth aspect of the present invention is the two-component heat conductive resin composition according to the fourth aspect of the present invention, wherein the polyisocyanate (II) has a biuret structure, It has an adduct structure, a nurate structure, or an allophanate structure.
If comprised in this way, when the 2nd component is a polyisocyanate which has a biuret structure or a nurate structure, the adhesiveness to a heat generating body or a cooling body will be provided to the mixture of a 2 component type heat conductive resin composition can do. When the second component is a polyisocyanate having an adduct structure or an allophanate structure, flexibility is imparted by the mixture of the two-component heat conductive resin composition, and the contact surface with the heating element or the cooling body. By reducing the interfacial thermal resistance, heat can be further efficiently transferred.

The two-component thermal conductive resin composition according to the sixth aspect of the present invention is the two-component thermal conductive resin composition according to the fourth aspect of the present invention, wherein the polyisocyanate (II) comprises a plurality of types. It contains a polyisocyanate and contains either a biuret structure, a nurate structure or both.
If comprised in this way, the adhesiveness to a heat generating body or a cooling body can be provided.

The two-component thermal conductive resin composition according to the seventh aspect of the present invention is the two-component thermal conductive resin composition according to any one of the fourth to sixth aspects of the present invention, The polyisocyanate (II) contains hexamethylene diisocyanate as an isocyanate species.
If comprised in this way, the yellowing by an ultraviolet-ray or a heat | fever can be suppressed and moderate softness | flexibility can be provided. In addition, a urethane film excellent in chemical properties such as mechanical properties and chemical resistance can be formed.

The two-component thermal conductive resin composition according to the eighth aspect of the present invention is the two-component thermal conductive resin composition according to any one of the first to seventh aspects of the present invention, The boron nitride scaly particle aggregate (III) is a ratio of 40 vol% or less of the total amount of the liquid polyol (I), polyisocyanate (II), and boron nitride scaly particle aggregate (III). Including.
If comprised in this way, content of the aggregate of the scale-like particle | grains of boron nitride can be made into an appropriate quantity.

The two-component heat conductive resin composition according to the ninth aspect of the present invention is the two-component heat conductive resin composition according to any one of the first to eighth aspects of the present invention, The first component further includes at least one additional filler selected from the group consisting of boron nitride, silica, alumina, aluminum nitride, cordierite, mullite, titanium oxide, zinc oxide, silicon carbide, diamond, and graphite. .
If comprised in this way, the heat conductivity of the formed heat conductive sheet can further be improved.

The two-component heat conductive resin composition according to a tenth aspect of the present invention is the two-component heat conductive resin composition according to the ninth aspect of the present invention, wherein the additional filler is the aluminum nitride, and The boron nitride is at least one selected from the group consisting of boron nitride, the boron nitride is a boron nitride whisker, and the aluminum nitride is an aluminum nitride whisker.
When configured in this way, a heat path can be formed so as to connect the gaps between the fillers, so that the thermal conductivity of the formed thermal conductive sheet can be further improved, and the filling rate of the filler can be increased while maintaining high thermal conductivity. Can be lowered.

The two-component heat conductive resin composition according to an eleventh aspect of the present invention is the two-component heat conductive resin composition according to the ninth aspect of the present invention, wherein the additional filler includes the boron nitride and the alumina. , And at least one selected from the group consisting of the aluminum nitride, the boron nitride is scaly, the alumina is spherical, and the aluminum nitride is spherical.
If comprised in this way, the heat conductivity of the formed heat conductive sheet can further be improved.

A two-component heat conductive resin composition according to a twelfth aspect of the present invention is the two-component heat conductive resin composition according to the eleventh aspect of the present invention, wherein the aggregates of the scale-like particles of boron nitride are used. (III) and the additional filler are powders, and the average particle size of the aggregate (III) of the boron nitride scaly particles is 10 to 500 μm, and the average particle size of the boron nitride scaly particles Is 1 to 50 μm, and the spherical alumina and spherical aluminum nitride have an average particle size of 1 to 200 μm.
If comprised in this way, since the average particle diameter of the aggregate (III) of the scale-like particle | grains of boron nitride is 10 micrometers or more, the formed sheet | seat can have sufficient thermal conductivity. Moreover, since it is 500 micrometers or less, an unevenness | corrugation cannot be made on the surface of a sheet | seat.

A two-component heat conductive resin composition according to a thirteenth aspect of the present invention is the above-described boron nitride scale in the two-component heat conductive resin composition according to the eleventh aspect or the twelfth aspect of the present invention. The mass ratio of aggregated mass (III) of particle-like particles and scale-like particles of boron nitride to the total mass of spherical alumina and spherical aluminum nitride is 60:40 to 5:95.
If comprised in this way, the ratio of an aggregate particle and an additional filler can be adjusted, the filling rate of spherical alumina is raised, rigidity is given to the mixture of a two-component type heat conductive resin composition, or boron nitride By increasing the filling rate of the scaly particle aggregate (III) and the boron nitride scaly particles, the filling rate of the spherical alumina is lowered to reduce the lightness and softness of the mixture of the two-component thermal conductive resin composition. It is preferable because the characteristics can be adjusted while maintaining the excellent thermal conductivity of the mixture of the two-component thermal conductive resin composition.

The heat conductive sheet which concerns on the 14th aspect of this invention is the heat | fever which consists of hardened | cured material of the two-component type heat conductive resin composition as described in any one aspect of the said 1st aspect-13th aspect of this invention. It is a conductive sheet.
With this configuration, since the heat conductive sheet is based on polyurethane, it has superior adhesion, adhesion and heat resistance to metal surfaces, etc., compared to heat conductive sheets based on acrylic and acrylic silicone. It can be a high thermal conductive sheet. Further, there is no contamination with low molecular siloxane, which is a concern when a silicone system is used as a base. Further, due to the aggregate of boron nitride scale-like particles, the orientation of the particles is not limited to a certain direction in the formed sheet, and as shown in FIG. 1, in the thickness (vertical) direction and the plane (horizontal) direction. It can have thermal conductivity.

The heat conductive sheet which concerns on the 15th aspect of this invention is a sheet form in the heat conductive sheet which concerns on the said 14th aspect of this invention, Comprising: It has a thickness of 5-1000 micrometers.
If comprised in this way, it can be used as a heat conductive sheet, for example, a thermal interface material (TIM) especially in the field of electronics.

The metal product according to the sixteenth aspect of the present invention includes, for example, as shown in FIG. 3, a metal member 21; and the heat according to the fourteenth aspect or the fifteenth aspect of the present invention that covers the metal member 21. A conductive sheet 1; In addition, the metal member should just be a metal member, for example, a metal plate is also included.
If comprised in this way, the metal member 21 can be closely_contact | adhered to another metal etc. via a heat conductive sheet.

An electronic apparatus according to a seventeenth aspect of the present invention is, for example, as shown in FIG. 3, the metal member 21; the electronic component 22: the metal member 21 and the electronic component 22 sandwiched between the metal component 21 and the electronic component 22. A heat conductive sheet 1 according to a fourteenth aspect or a fifteenth aspect.
If comprised in this way, the heat which generate | occur | produced in the electronic component can be efficiently transmitted to metal metal members (for example, heat sink), and the heat dissipation effect of an electronic component can be improved.

  Since the two-component heat conductive resin composition of the present invention does not contain a solvent, it does not require drying and can easily form a heat conductive sheet. Furthermore, the formed heat conductive sheet is excellent in heat conductivity, heat resistance, and adhesiveness. In particular, since the heat conductive sheet contains aggregates of scale-like particles of boron nitride, the crystal orientation is not limited to a certain direction, and the heat conductive sheet has high heat conductivity not only in the plane direction but also in the thickness direction. be able to.

It is a cross-sectional schematic diagram of the heat conductive sheet 1 which concerns on the 2nd Embodiment of this invention. It is a cross-sectional schematic diagram of the heat conductive sheet containing scaly boron nitride as a filler. It is a figure which shows the usage example of the heat conductive sheet 1 which concerns on the 2nd Embodiment of this invention. It is a SEM image (1000 times) of an aluminum nitride whisker. It is a SEM image (1000 times) of the aluminum nitride whisker which was crushed into particles. It is the schematic of the sample used for adhesiveness evaluation in the Example.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same or similar reference numerals, and redundant description is omitted. Further, the present invention is not limited to the following embodiments.

≪Two-component thermal conductive resin composition≫
The two-component thermal conductive resin composition according to the first embodiment of the present invention is composed of two types of components, a first component and a second component, which are separately prepared and stored. The first component and the second component are kept separated until mixed and cured. The first component includes an inorganic filler that is an aggregate (III) of scale-like particles of liquid polyol (I) and boron nitride. The second component contains polyisocyanate (II). The first component and the second component are mixed and cured to form a urethane resin containing aggregates of scale-like particles of boron nitride.

≪First ingredient≫
Liquid polyol (I)
As liquid polyol (I), acrylic polyol, polyester polyol, polyether polyol, polycarbonate polyol, aliphatic polyol, aliphatic modified polyol, aromatic polyol, polybutadiene polyol, glycols, derivatives thereof, acrylic diol, polyester diol And polyether diol, polycarbonate diol, aliphatic diol, aliphatic modified diol, aromatic diol, polybutadiene diol, and derivatives thereof. Among them, a polycarbonate polyol or a polycarbonate diol can form a mixture of a two-component heat conductive resin composition having excellent heat resistance, high adhesion to heat-generating parts, cooling parts, etc. and having appropriate flexibility. .

  The molecular weight of the liquid polyol (I) is preferably from 50 to 10,000. More preferably, it is 100-5000, Most preferably, it is 200-2000. When the molecular weight of the liquid polyol (I) is 200 or more, the viscosity of the first component is too low to prevent dripping when attached to a heat-generating component or a cooling component, and the filler settles during storage. By doing, it can prevent that a hard cake arises. Also, when the molecular weight is 2000 or less, the viscosity of the first component is reduced, the followability to the heating element and the cooling body and handling are improved during coating and film formation, the interface thermal resistance of the contact surface is lowered, and the heat is reduced. Can communicate efficiently.

Aggregates of scaly particles of boron nitride (III)
The aggregate (III) of the scale-like particles of boron nitride is preferably one in which the scale-like particles of boron nitride, which are a plurality of primary particles, gather and exist as aggregates (lumps). Aggregation may be chemical aggregation or physical aggregation, and after the sheet is formed, the aggregate in the urethane resin can exhibit thermal conductivity in multiple directions due to the random orientation of the scaly particles. Is preferred.
The shape of the particles constituting the aggregate may be any shape that is advantageous for random orientation, and examples thereof include non-spherical shapes such as a scale shape, a plate shape, an oval shape, and a rod shape. In particular, hexagonal boron nitride having a high thermal conductivity and a low hardness is preferable because it has a scale-like structure.

The reason why the aggregate is used as the filler will be described by taking boron nitride as an example.
Boron nitride has a scaly particle structure, and the scaly particles exist in a state where they overlap and are oriented in a certain direction. Therefore, the thermal conductivity of boron nitride is excellent in the major axis direction of the scaly particles, but is inferior in the direction perpendicular to the major axis direction. That is, the thermal conductive sheet containing boron nitride has excellent thermal conductivity in the major axis direction of the particles. For example, in the heat conductive sheet 2 shown in FIG. 2, the scaly particles 13 are oriented in the surface direction (horizontal direction), and the heat conductivity in the surface direction increases, but the heat conduction in the thickness direction (vertical direction). The rate is small.
The two-component thermal conductive resin composition of the present invention is an aggregate (III) of scale-like particles of boron nitride, and contains an aggregate in which the orientation of the particles is random. Therefore, the heat conductive sheet 1 shown in FIG. 1 is rich in the major axis direction of the particles constituting the aggregate 11 and ensures heat conductivity in all directions. When the two-component thermal conductive resin composition is cured, it is considered that the formed sheet can have thermal conductivity in the surface direction (horizontal direction) and the thickness direction (vertical direction).

  The aggregate (III) of the scale-like particles of boron nitride is preferably powder, paste, wire or the like. In particular, since a uniform state is obtained in the first component, it is preferable to mix the powder into the first component. In the case of powder, the average particle diameter is preferably 10 to 1000 μm. More preferably, it is 10-500 micrometers. Most preferably, it is 10-300 micrometers. When the thickness is 10 μm or more, the viscosity of the first component does not become too high, and workability during film formation is good. Moreover, the heat conductivity of the formed heat conductive sheet does not deteriorate. When the thickness is 1000 μm or less, the surface of the formed heat conductive sheet is not uneven. Further, the sedimentation of the aggregates is fast and the storage stability of the first component does not deteriorate. In addition, the said numerical value is an illustration and the particle size of an aggregate does not necessarily need to be the said range. Depending on the thickness of the heat conductive sheet, the same or a little smaller than the thickness of the sheet is preferable because the heat transfer coefficient is the highest. Two or more types of aggregates having different forms or average particle diameters may be used.

  In the present specification, the average particle size is based on particle size distribution measurement by a laser diffraction / scattering method. That is, when the powder is divided into two from a certain particle size by the wet method using the analysis based on the Franhofer diffraction theory and Mie's scattering theory, the larger side and the smaller side are equivalent (volume basis). Was the median diameter.

Additional filler Primary particles may be added as an additional filler in the form of addition to the aggregate (III) of scale-like particles of boron nitride. The additional filler is preferably at least one of boron nitride, silica, alumina, aluminum nitride, cordierite, mullite, titanium oxide, zinc oxide, silicon carbide, diamond, and graphite. In particular, boron nitride, cordierite, mullite, alumina, and graphite are preferable because the thermal conductivity of the formed thermal conductive sheet can be further improved. Silica is preferable because it can impart thixotropy, can adjust the viscosity of the first component, and has an effect of preventing dripping. Alumina is preferable when the particle size is large because aggregation of nitrides between the alumina particles is difficult to break (the crystal pieces can be prevented from falling apart). Zinc oxide is preferable because it is excellent in dispersibility and can further disturb the crystal orientation of the aggregate. The additional filler may be used as a single type or as a mixture of a plurality of types.

The additional filler may be powder, paste, wire or the like. In order to obtain a uniform state in the first component, it is preferable to mix the powder. The shape of the additional filler is not limited to the scale shape or the spherical shape, and fillers of any shape and material such as a crushed particle shape, a porous shape, a tetrapot shape, and a fiber shape can be used. The average particle size of the additional filler is preferably 0.001 to 200 μm. More preferably, it is 0.005-100 micrometers. Most preferably, it is 0.07-50 micrometers. When it is 0.001 μm or more, the viscosity of the first component does not become too high, and the workability during film formation is good. Moreover, the heat conductivity of the formed heat conductive sheet does not deteriorate. When the thickness is 200 μm or less, the surface of the formed heat conductive sheet is not uneven. Moreover, the sedimentation of the filler is fast and the storage stability of the first component does not deteriorate.
When the additional filler is a spherical particle, it is preferable to make the average particle size of the additional filler smaller than the average particle size of the aggregate, because it can enter the gaps of the aggregate and improve the thermal conductivity. In particular, when adding an additional filler for coloring purposes, if particles having an average particle size smaller than that of the aggregate are used, it is easy to disperse uniformly and the contact between the aggregates is not hindered. It is preferable because there is no.

The additional filler may be a whisker (short fiber). The whisker is preferably at least one of aluminum nitride whisker and boron nitride whisker. In particular, the aluminum nitride whisker has a high thermal conductivity, and since it is fibrous, it can efficiently form a heat path and achieve a high thermal conductivity with a low content. It is preferable because flexibility can be imparted to a mixture of products and weight can be reduced. Since boron nitride whiskers have a high thermal conductivity and are fibrous, they can efficiently form a heat path and achieve high thermal conductivity with a low content. It is preferable because flexibility can be imparted to the mixture, and since the specific gravity of the filler is small, further weight reduction is possible.
The shape of the whisker is not particularly limited. Generally, the fibrous thing (FIG. 4) marketed may be used, a fibrous whisker may be crushed and used, and it may be crushed to a particulate form (FIG. 5).

  An additional filler may be used individually by 1 type, may be used in mixture of multiple types, and naturally a filler of a different shape may be mixed and used. It is preferable to use at least one selected from the group consisting of aluminum nitride whiskers and boron nitride whiskers as the additional filler because high thermal conductivity, flexibility, and weight reduction are possible. When at least one selected from the group consisting of boron nitride scaly particles, spherical alumina, and spherical aluminum nitride is used as the additional filler, the thermal conductivity of the formed thermal conductive sheet can be further improved, and spherical By increasing the packing rate of alumina to give rigidity to the mixture of the two-component thermal conductive resin composition, or by increasing the packing rate of the scaly particles of boron nitride, the packing rate of the spherical alumina is decreased and the two-component type The characteristics can be adjusted while maintaining the excellent thermal conductivity of the mixture of the two-component heat conductive resin composition, such as imparting lightness and softness to the mixture of the heat conductive resin composition.

When the first component is mixed with 5 to 150 parts by weight of aggregates (III) of scale-like particles of boron nitride with 100 parts by weight of liquid polyol (I), the formed heat conductive sheet has good heat conduction. The effect can be obtained. Considering the working efficiency when forming a film from the two-component heat conductive resin composition, the aggregate (III) is preferably 10 to 100 parts by weight with respect to 100 parts by weight of the liquid polyol (I). When the aggregate (III) is 5 parts by weight or more, sufficient heat conduction characteristics of the aggregate (III) can be obtained. Moreover, when it is 150 parts by weight or less, the viscosity of the first component is not increased excessively, and the operability is not impaired, and the problem that the aggregate (III) further aggregates in the first component does not occur. Furthermore, it is possible to avoid the occurrence of cracks in the heat conductive sheet formed with weak adhesion between the aggregates (III) due to too little polyurethane resin after film formation. Further, there is no problem that the heat conductive sheet becomes too hard and the followability to the metal surface or the like is impaired.
In addition, the total amount of the filler to contain is 5-700 weight part with respect to 100 weight part of liquid polyol (I) as above-mentioned. When adding an additional filler, it is preferable that an additional filler shall be 1-2000 weight part with respect to 100 weight part of aggregates (III).
If it is said range, a heat conductive sheet will be obtained in the state embedded in the layer of a polyurethane resin, without a filler projecting from the cured layer after hardening.

Additive The first component may further contain a dispersant / antifoaming agent / color pigment / silane coupling agent / polymerization catalyst as an additive.
Dispersants include hydroxyl group-containing carboxylic acid esters, salts of long chain polyaminoamides and high molecular weight acid esters, salts of high molecular weight polycarboxylic acids, salts of long chain polyaminoamides and polar acid esters, high molecular weight unsaturated acid esters, Molecular copolymer, modified urea, modified polyurethane, modified polyacrylate, polyether ester type anionic activator, naphthalene sulfonic acid formalin condensate salt, aromatic sulfonic acid formalin condensate salt, polyoxyethylene alkyl phosphate ester, poly Oxyethylene nonyl phenyl ether, polyoxylene monoalkyl ether, and stearylamine acetate are used. By adding 0.1 to 35 parts by weight with respect to 100 parts by weight of the filler, aggregation of the filler can be prevented and the storage stability of the first component can be improved.
Antifoaming agents include silicone-based antifoaming agent, modified silicone-based antifoaming agent, silica-based antifoaming agent, wax, polysiloxane, polyether-modified polydimethylsiloxane, foam-breaking polymer, paraffinic oil, foam-breaking fat Group derivatives and the like. Addition of 0.01 to 5 parts by weight with respect to 100 parts by weight of the first component shows defoaming properties and improves workability when forming a film from the two-component heat conductive resin composition.
Organic pigments and inorganic pigments can be used as the color pigment.
A commercially available coupling agent is used for the silane coupling agent. Among these, silane coupling agent Silaace (registered trademark) (S330, S510, S520, S530) manufactured by JNC Corporation is preferable. Improve the adhesion between the metal plate and the heat conductive sheet formed from the two-component heat conductive resin composition by adding 1 to 10 parts by weight to 100 parts by weight of the liquid polyol (I). Can do.
A polymerization catalyst is not specifically limited, What is used in a polyurethane resin composition can be used variously. As a polymerization catalyst, metal catalysts, such as an organic tin catalyst, an organic lead catalyst, and an organic bismuth catalyst, an amine catalyst etc. can be illustrated, for example. Examples of the organic tin catalyst include dioctyltin dilaurate, dibutyltin diacetate, dibutyltin dilaurate, and dioctyltin diacetate. Examples of the organic lead catalyst include lead octylate, lead octenoate, lead naphthenate and the like. Examples of the organic bismuth catalyst include bismuth octylate and bismuth neodecanoate. As amine catalysts, diethylenetriamine, triethylamine, N, N-dimethylcyclohexylamine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine, trimethylene Examples thereof include diamine, dimethylaminoethanol, bis (2-dimethylaminoethyl) ether and the like. Moreover, as a polymerization catalyst, you may use an organometallic compound, a metal complex compound, etc. The polymerization catalyst may be used alone or in combination of two or more. The content of the polymerization catalyst is added by 0.00001 to 10 parts by weight with respect to 100 parts by weight of the first component, thereby promoting the curing reaction when mixed with the second component and lowering the curing temperature or curing. Time can be shortened and workability at the time of film formation is improved.

≪Second ingredient≫
Polyisocyanate (II)
As polyisocyanate (II), non-yellowing polyisocyanate is preferable. Specific examples include at least one selected from the group consisting of xylylene diisocyanate, hydrogenated xylylene diisocyanate, 1,5-pentamethylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. Furthermore, a polyisocyanate having a biuret structure, an adduct structure, a nurate structure, or an allophanate structure is more preferable. The polyisocyanate may be used as a single type or as a mixture of a plurality of types. Moreover, since polyisocyanate (II) contains either or both of the polyisocyanate having a biuret structure or a nurate structure, the adhesiveness is improved, which is preferable. Furthermore, it is more preferable that the polyisocyanate (II) contains at least one polyisocyanate having a nurate structure because moisture resistance is improved.

In the second component, the filler contained in the first component may be contained instead of the first component, or part of the filler contained in the first component may be contained, and the filler contained in the first component. A filler may be added so as to be further added to.
Further, the second component may contain the constituent component (for example, additive) described in the first component instead of the first component, or may include a part thereof, or may be further added. You may let them.

The first component is prepared by weighing and adding aggregates (III) of boron nitride scaly particles to the liquid polyol (I), and stirring and kneading using a stirrer or kneading device such as a rotation / revolution mixer. What is necessary is just to mix to such an extent that it deaerates and aggregation of a filler is eliminated. During mixing, an additive such as a dispersant may be added as necessary, or an additional filler may be added to adjust the viscosity of the first component according to the film forming method.
The adjustment of the second component may be performed by weighing polyisocyanate (II) and mixing and stirring after weighing when plural kinds of mixtures are used.

  As described above, the two-component heat conductive resin composition of the present invention does not contain a solvent, is easy to handle as compared with paints using an aqueous solvent, an organic solvent, and the like, and other than the components that become the heat conductive sheet. Since it does not include weight, it is easy to transport. Furthermore, it can be a measure against VOC (Volatile Organic Compounds). The two-component heat conductive resin composition of the present invention can easily form a heat conductive sheet having excellent heat conductivity and adhesiveness by heat compression molding after mixing.

≪Heat conduction sheet≫
The heat conductive sheet according to the second embodiment of the present invention shown in FIG. 1 is a sheet of resin formed from the two-component heat conductive resin composition according to the first embodiment of the present invention. It is. This heat conductive sheet mixes a 1st component and a 2nd component, and similarly stirs and defoams using stirring machines and kneading apparatuses, such as an autorotation / revolution mixer. After applying the mixed two-component heat conductive resin composition, the coating film can be obtained by heat compression molding.

  As a method for applying the mixed two-component heat conductive resin composition, it is preferable to use a wet coating method for uniformly coating. Among the wet coating methods, when a small amount is prepared, a coating method using an applicator capable of forming a film even with a highly viscous liquid is preferable. If productivity is important, gravure coating, die coating, bar coating, reverse coating, roll coating, slit coating, dipping, kiss coating, reverse kiss coating, air knife coating, curtain coating Method, rod coating method and the like are preferable. The wet coating method can be appropriately selected according to the required film thickness, viscosity, etc. from these methods. Also, when the filler content of the mixed two-component thermal conductive resin composition is large and the viscosity is not suitable for the wet coating method, paste extrusion method, compression molding method, transfer molding method, injection molding method, casting method The lamination molding method and the calendar molding method are preferable. From these methods, it can be appropriately selected according to the required film thickness, shape, attachment location and the like. When producing a small amount, a compression molding method using a heating press is preferred.

In addition, it is preferable to apply the mixed two-component heat conductive resin composition so that the thickness of the cured sheet is 5 to 1000 μm. More preferably, it is 50-500 micrometers. Most preferably, it is 100-400 micrometers. When the thickness is 5 μm or more, the thicker the film, the better the tracking of unevenness on the metal surface and the like, and the sufficient adhesion can be obtained. When the thickness is 1000 μm or less, the heat transfer coefficient increases as the thickness decreases. Therefore, an appropriate film thickness is selected according to the application.
After coating, the coating film may be heated and pressed using a compression molding machine, and then heated and cured.

  The hardness at 50 ° C. of the cured product obtained by curing the two-component heat conductive resin composition is preferably ASKER C 25-95, and the hardness at 25 ° C. is preferably ASKER C 70 or higher. More preferably, it is ASKER C 25-95 at 50 ° C., and the hardness at 25 ° C. is ASKER C 80 or more. More preferably, it is ASKER C 60-95 at 50 ° C., and ASKER C 80 or more at 25 ° C. The hardness of the cured product at 25 ° C. is preferably ASKER C 80 or more because the adhesive strength of the formed heat conductive sheet and the like can be maintained. When it is ASKER C 95 or less at 50 ° C., the effect of preventing cracks and the ability to follow irregularities on the metal surface and the like can be obtained by appropriate flexibility, and therefore, the interfacial thermal resistance is preferably lowered. The measurement was performed in consideration of not only the hardness at 50 ° C. but also the hardness at room temperature (25 ° C.) in consideration of changes in hardness due to temperature (difference in handling properties).

The formed thermal conductive sheet (cured product) contains aggregates of scale-like particles of boron nitride having high thermal conductivity. For this reason, when the formed sheet is disposed between a metal member having a high thermal conductivity such as a heat sink and an electronic component having a heat generating part, the heat generated in the heat generating part is efficiently conducted through the sheet to form a metal. Is transmitted to the member.
Furthermore, the formed heat conductive sheet contains a polyurethane resin. Therefore, it is excellent in heat resistance and the mass loss temperature of 5% is 270 ° C. or higher. Since the adhesion to the metal surface is also excellent, the sheet follows the irregularities on the surface of the metal member and the electronic device, and the metal member and the electronic device can be adhered to each other. Moreover, since it is excellent in ductility, processing after painting is also possible.
As described above, polyurethane is preferable because it is excellent in heat resistance and adhesion to metals and the like, and a polyurethane obtained by curing a two-component heat conductive resin composition is particularly excellent in heat resistance and adhesiveness. Is preferable. Of these, polycarbonate polyurethane is most preferred. The heat conductive sheet made of polycarbonate polyurethane is particularly excellent in adhesion and heat resistance, and because it is a two-component type, it has fluidity before film formation, so it is cured after following irregularities on the surface of metal, etc. In particular, there is an advantage of excellent adhesion and adhesiveness.

  As described above, the heat conductive sheet formed from the two-component heat conductive resin composition of the present invention functions as a heat conductive film. Therefore, after forming a heat conductive sheet, as shown in FIG. 3, you may comprise between the metal member 21 which functions as a heat radiating member, and the electronic component 22. As shown in FIG. That is, what is necessary is just to arrange | position so that the heat conductive sheet 1 and the electronic component 22 may contact directly. Specifically, as shown in FIG. 3, the metal member 21 may be an existing metal heat dissipation member such as a heat sink. In FIG. 3, the heat conductive sheet 1 is disposed between the heat sink and the electronic component 22. In addition, the metal used as application | coating object is not specifically limited, Copper, iron, magnesium, aluminum, and those alloys can be illustrated. These metals are particularly preferable because of their high thermal conductivity.

  The metal member (resin-coated metal) on which the heat conductive sheet is formed may be bonded to the electronic component 22 using an adhesive. The adhesive is preferably an acrylic, silicone, or epoxy adhesive. Alternatively, the resin-coated metal may be fixed to the electronic device 22 using screws or metal fittings. That is, any resin coating metal may be used as long as the metal can be fixed to the electronic component 22 in close contact.

  In the metal product, the metal member 21 may be a metal plate (plate shape), and may be a resin-coated metal having a metal plate. Further, the electronic component 22 may be a self-heating device such as a CPU or a battery of a device such as a smartphone or a PC, a machine, or the like.

  Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to the contents described in the following examples.

The component material which comprises the heat radiating member used for the Example of this invention is as follows.
<Polycarbonate polyol>
PCD1: Asahi Kasei Chemicals Corporation / Duranol T5650J
PCD2: Asahi Kasei Chemicals Corporation / Duranol G3452
PCD3: Asahi Kasei Chemicals Corporation / Duranol T5650E
(Duranol is a registered trademark)
<Polyisocyanate>
HDI1: Asahi Kasei Chemicals Corporation / Duranate 24A-100 (Biuret)
HDI2: Asahi Kasei Chemicals Corporation / Duranate TKA-100 (Nurate)
HDI3: Asahi Kasei Chemicals Corporation / Duranate TSE-100 (Nurate)
HDI4: Asahi Kasei Chemicals Corporation / Duranate AE700-100 (Adduct)
HDI5: Asahi Kasei Chemicals Corporation / Duranate D201 (Allophanate)
HDI6: Mitsui Chemicals / Takenate D-177N (Nurate)
HDI7: Mitsui Chemicals / Takenate D-178NL (Allophanate)
(Duranate and Takenate are registered trademarks)
<Filler>
Boron nitride BN1: Momentive (combined) / PTX-25 (aggregate, average particle size 25 μm)
BN2: Momentive (combined) / PTX-60 (aggregate, average particle size 60 μm)
BN3: Denka Co., Ltd./FP-70 (in aggregate form, average particle size 70 μm)
BN4: Momentive (combined) / PT-350 (in aggregate form, average particle size 125-150 μm)
BN5: 3M / Platelets 15/400 (in aggregate form, average particle size 125-190 μm)
BN6: Momentive (combined) / PT-670 (in aggregate form, average particle size 300-500 μm)
BN7: 3M / Platelet 003 (scale-like, average particle size 3-5 μm)
BN8: Momentive (go) / PT-110 (scale-like, average particle size 45 μm)
・ Aluminum oxide (alumina)
ALO1: DENKA CORPORATION / DAW-7 (average particle size 9 μm)
ALO2: DENKA CORPORATION / DAW-20 (average particle size 20 μm)
ALO3: DENKA CORPORATION / DAW-45 (average particle diameter 45 μm)
Aluminum nitride ALN1: Furukawa Electronics Co., Ltd./FAN-f50-A1 (average particle size 50 μm)
ALN2: THRUTEK APPLIED MATERIALS CO. , LTD / AlN300RF (average particle size 30 μm)
ALN3: U-MaP / crushed AlN whisker (needle shape, needle length 10-100 μm)
・ Aluminum hydroxide ALOH: Wako Pure Chemical Industries, Ltd./Aluminum hydroxide ・ Synthetic cordierite CO: Marus glaze joint stock company / SS-1000 (average particle size 1.7 μm)
・ Silicon dioxide (silica)
SIO: Nippon Aerosil Co., Ltd./AEROSIL RX300 (average particle size 7 nm)
(AEROSIL is a registered trademark)
・ Zinc oxide ZNO: Amtec Co., Ltd./Panatetra WZ-0531
<Additives>
Dispersant: Evonik / TEGO Dispers 690
Dispersant: Big Chemie / DISPERBYK-2152
(TEGO is a registered trademark)

<Measurement method of particle size distribution>
The average particle diameter (median diameter) of each particle was measured using a laser diffraction scattering type particle size distribution measuring apparatus LA-950V2 manufactured by Horiba. That is, using the analysis based on the Franchoffer diffraction theory and Mie's scattering theory, when measuring by a wet method and dividing the powder into two from a certain particle size, the larger side and the smaller side are equivalent (volume basis) ) Is the median diameter. The measurement was performed using a wet method, a solution in which a sample was dispersed after adding a small amount of a measurement sample (about one earpick) in pure water and then treating in an ultrasonic cleaner for 3 minutes. The concentration of the slurry at the time of measurement was adjusted so that the laser transmittance was 80%.

<Sample preparation method 1>
The polycarbonate polyol, filler powder and additives are weighed, preliminarily stirred with a spoon, and then rotated and revolved using a rotating / revolving mixer (Shinky Corporation Awatori Rentaro ARE-250) at a rotational speed of 2000 rpm. After stirring for 90 seconds, defoaming was performed for 60 seconds at a rotational speed of 2200 rpm to adjust the first component. Thereafter, the polyisocyanate is weighed as a second component and then added, and the mixture is stirred for 30 seconds at a rotational speed of 2000 rpm, whereby the mixed two-component heat conductive resin composition (hereinafter referred to as a heat conductive resin composition) is mixed. Prepared.

<Sample preparation method 2>
The polycarbonate polyol, filler powder and additives are weighed, preliminarily stirred with a spoon, and then stirred for 1 minute at a rotational speed of 500 rpm using a small mixer (Powder Lab PWB manufactured by Nihon Coke Kogyo Co., Ltd.). Then, stirring was further performed at 1000 rpm for 1 minute, 2000 rpm for 5 minutes, and 3000 rpm for 5 minutes to adjust the first component. Thereafter, polyisocyanate is weighed and added as the second component, and the mixture is stirred for 90 seconds at a rotation speed of 2000 rpm using a rotation / revolution mixer (Shinky Corporation Awatori Rentaro ARE-250). The following heat conductive resin composition was prepared by performing defoaming at 2200 rpm for 60 seconds and stirring again at a rotational speed of 2000 rpm for 30 seconds.

Example 1
100 parts by weight of PCD1, 72.1 parts by weight of BN1, and 44.2 parts by weight of HDI1 were weighed and adjusted according to the procedure of Sample Preparation Method 1 to obtain a sample of Example 1.
<< Examples 2 to 5 >>
Samples were prepared in the same manner as in Example 1 except that the type and amount of filler, or the type of polyol were different, and the samples of Examples 2 to 5 were used.
<< Comparative Examples 1-5 >>
Samples of Comparative Examples 1 to 5 were used in the same manner as in Example 1 except that the type and filling amount of the filler were different.
Hereinafter, the filler filling rate (vol%) is the volume ratio of the filler in the heat conductive resin composition, and the total filling rate (vol%) is the capacity of the filler in the heat conductive resin composition when an additional filler is included. It is a ratio.

<< Examples 6 to 14 >>
Further, in order to adjust the viscosity and enhance the heat conduction performance, aggregated boron nitride and an additional filler were added as aggregate fillers. The ratio of the filler mixing ratio and the filler filling amount is shown below. In Example 14, 4 wt% of TEGO Dispers 690 was added to the resin component. The sample preparation procedure is the same as in Example 1.

<< Comparative Examples 6-9 >>
A carboxyl group-containing polyol was synthesized by the method described in International Publication No. 2012/157627 using polycarbonate diol T5650J, 2,2-dimethylolbutanoic acid, 24A-100, and 2-propanol as raw materials. Thereafter, the synthesized carboxyl group-containing polyol and epoxy resin jER807 were weighed at the blending ratio described in International Publication No. 2012/157627, and the filler powder was added so as to have the blending described in Table 3, followed by a rotation / revolution mixer. (Shinky Co., Ltd. Awatori Rentaro ARE-250), after stirring for 90 seconds at a rotation speed of 2000 rpm, defoaming for 60 seconds at a rotation speed of 2200 rpm, and further stirring for 30 seconds at a rotation speed of 2000 rpm The following heat conductive resin composition was prepared.

<< Examples 15, 16, 27-29 >>
The samples of Examples 15, 16, and 27 to 29 were prepared in the same manner as in Example 1 except that the type and amount of filler, or the type of isocyanate were different.
<< Examples 17 to 26 >>
PCD1, various fillers, and polyisocyanate were weighed and adjusted by the procedure of Sample Preparation Method 2 to obtain samples of Examples 17 to 26.

<< Examples 30 to 32 >>
Except for the difference in filler type and filling amount, adjustments were made in the same manner as in Example 1 to obtain Examples 30 to 32.
<< Example 33 >>
PCD1, various fillers, and polyisocyanate were weighed and adjusted according to the procedure of Sample Preparation Method 2 to obtain a sample of Example 33.

<Adjustment of thermal conductivity evaluation sample>
The heat conductive resin compositions of Examples 1 to 33 and Comparative Examples 1 to 5 were applied on a glass cloth sheet, and a compression molding machine mini test press-10 type small heating press manufactured by Toyo Seiki Seisakusho Co., Ltd. was used. After forming into a sheet shape at a load of 0.1 MPa and room temperature so that the surface becomes flat, the temperature was raised to 100 ° C. and heated for 30 minutes to be cured. The clearance gap was adjusted for each sample so that the cured film had a thickness of about 200 μm to 400 μm. The film thickness was measured using a DIGIMICRO FM-501 manufactured by Nikon.
The cured heat conductive resin composition was peeled off from the glass cloth sheet and used as an evaluation sample.
Moreover, about Comparative Examples 6-9, the sample was produced by the method similar to Example 1 except setting the temperature of a small heat press to 150 degreeC.

<Evaluation of thermal conductivity>
The measurement of the thermal conductivity in the thickness direction was performed using a thermal conductivity measuring device TCM1000 manufactured by Resuka Co., Ltd. That is, the thermal conductivity in the thickness direction was measured using the measurement principle of the unidirectional heat flow steady comparison method. Samples at the time of measurement were prepared with a film thickness in the range of about 200 μm to 400 μm, and the average of three points was noted.

  Using the samples of Examples 1 to 5 and Comparative Examples 1 to 3, the thermal conductivity in the thickness direction was evaluated.

  From the results shown in Table 6, the cured thermal conductive resin composition has excellent thermal conductivity in the thickness direction, and the heat dissipating member using the thermal conductive resin composition of the present invention has a low filling rate. Excellent heat dissipation performance in some cases. From the results of thermal conductivity tests using the thermally conductive resin compositions of Examples 1 to 5 and Comparative Example 1, aggregated boron nitride fillers are preferable to scale-like boron nitride fillers. Moreover, from the result of the thermal conductivity test using the thermal conductive resin compositions of Examples 1 to 5 and Comparative Examples 2 and 3, by using the aggregated boron nitride filler, the filling rate of the filler to the resin is Even if it is small, since it exhibits excellent thermal conductivity in the thickness direction, it is possible to reduce the weight of the resin composition, which is preferable.

  The thermal conductivity was evaluated using the samples of Examples 6 to 14 and Comparative Examples 4 to 9.

As shown in Examples 6 to 14 in Table 7, even when an additional filler is added to the boron nitride aggregate filler, high thermal conductivity is exhibited. Further, when Examples 8 to 13 and Comparative Examples 4 and 5 are compared, Examples 8 to 13 have a smaller filler filling rate, and boron filler is 40 wt% or less of the fillers filled. Nevertheless, it has a thermal conductivity of 2 times or more, which is preferable.
Further, in the case of a composition using 73.9 vol% (85 wt%) of scale-like boron nitride particles in the filler of Comparative Example 6 in Table 8 and epoxy urethane as the binder resin, the film was brittle and was not self-supporting. The thermal conductivity could not be measured. In the case of a composition using scale-shaped boron nitride particles 33.3 vol% (50 wt%) as the filler of Comparative Example 7 and epoxy urethane as the binder resin, the thermal conductivity is about 0.6 W / m · K. Even if it is very small and it compares with Examples 1-5 whose filling rate of the filler shown in Table 6 is 30 vol% or less, it turns out that performance is largely inferior. Further, in the case of the compositions of Comparative Examples 8 and 9, in which alumina or aluminum nitride and scale-like boron nitride particles are used for the filler, and epoxy urethane is used for the binder resin, the filler is compared with Examples 8-13. Although the total filling amount is the same as 40 vol%, the thermal conductivity is as small as about 1 W / m · K.
For this reason, it is preferable that at least one of the fillers contained in the resin composition is an aggregate of boron nitride scale-like particles, since it exhibits excellent thermal conductivity.

  The thermal conductivity was evaluated using the samples of Examples 15 to 29.

As shown in Examples 15 to 29 in Table 9, the resin composition of the present invention may contain aggregates of two or more types of boron nitride scale-like particles having different particle diameters. By adjusting the ratio between the aggregate particles and the additional filler as in Examples 15 and 16, the alumina filling rate is increased to give rigidity as in Example 15, or the filler filling is performed as in Example 16. It is preferable because the characteristics of the composition can be adjusted while maintaining the excellent thermal conductivity of the resin composition, such as reducing the rate and imparting lightness and softness.
Further, as shown in Examples 20, 21, 23-26, when the second component contains at least one adduct structure or polyisocyanate having an allophanate structure, the resin composition of the present invention has flexibility. This is preferable because the heat resistance can be further efficiently transferred by lowering the interfacial thermal resistance of the contact surface with the heating element and the cooling body.
As shown in Examples 27 and 28, it is preferable to use aluminum nitride as the additional filler because the thermal conductivity is further improved.
As shown in Example 29, when the molecular weight of the polyol is small, the viscosity of the first component is decreased, and the followability to the heating element and the cooling body and the handling are improved during coating and film formation. It is preferable because the interface thermal resistance is lowered and heat can be transferred efficiently.

  As shown in Examples 30 to 33 in Table 10, the additional fillers of the resin composition of the present invention are not only scale-like or spherical fillers, but also crushed particles, porouss, tetrapots, fibers, etc. Any filler of any shape and material can be used. It is preferable to add cordierite as in Example 30 because rigidity can be imparted to the resin composition and not only the thermal conductivity but also the infrared emissivity is improved. Moreover, when fumed silica is added like Example 31, the fluidity | liquidity of the resin composition before hardening can be adjusted, and it is preferable. As in Examples 32 and 33, when a tetrapot, fiber, or needle filler is added, a heat path can be formed so as to connect the gaps between the fillers. The rate can be maintained and the thermal conductivity can be further increased, which is preferable. In particular, when a whisker is used as an additional filler, the effect of improving the thermal conductivity is more easily obtained, which is preferable.

<Adjustment of adhesive evaluation sample>
The thermal conductive resin compositions of Examples 5, 15, 17-18, 20-26, and 29 were applied to a copper plate having a thickness of 0.4 mm, and a similar copper plate was placed on the copper plate to sandwich the thermal conductive resin composition. Komi, Toyo Seiki Seisakusho Co., Ltd. compression molding machine mini test press -10 type small heating press was used to mold the test piece at a load of 0.1MPa at room temperature, then heated to 100 ° C and heated for 60 minutes Cured. A test piece having the shape of FIG. 6 was prepared so that the area of the adhesive surface was 10 mm long and 10 mm wide.
Moreover, about Comparative Examples 6-9, the sample was produced by the method similar to Example 5 except setting the temperature of a small heat press to 150 degreeC.

<Evaluation of adhesive strength>
The adhesive strength was measured using the tensile test function of a tabletop precision universal testing machine Autograph AGS-10kNX manufactured by Shimadzu Corporation. That is, a tensile shear strength test was performed according to JIS K6850. However, the test piece of the shape of FIG. 6 was used for the sample as described above.

<Evaluation of adhesive strength after wet heat test>
The test piece prepared in the same manner as in the adhesive strength evaluation is left in a constant temperature and high humidity bath at a temperature of 85 ° C. and a humidity of 85% for one week, and then the extracted test piece is used in the same procedure as the evaluation of the adhesive strength. The test was conducted.

When the adhesive strength of each sample of Table 11 is compared, all of the samples of Examples 5, 15, 17-18, 22, and 29, in which the second component is a polyisocyanate having a biuret structure or a nurate structure, are 1N. / Mm ² is preferable because a result of ² or more is obtained. On the other hand, in Examples 20, 21, and 23, in which the second component is made of a polyisocyanate having an adduct structure or an allophanate structure, the film has a low hardness, so that the elongation of the resin was observed during the test and the adhesive strength was 1 N / It was less than mm ^2.
However, as shown in Examples 24-26, the second component is at least one polyisocyanate having an adduct structure or allophanate structure and at least one polyisocyanate having either a biuret structure or a nurate structure. In any case, the result shows that the adhesive strength is 1 N / mm ² or more, the resin composition is given adhesion to the heating element or the cooling body, and the thermal conductivity is good as shown in Table 9 Therefore, it is preferable.
On the other hand, regarding Comparative Examples 6 to 9, the tensile shear strength is less than 1 N / mm ² , indicating that the adhesiveness is poor. Moreover, about Comparative Examples 6-9, since hardening temperature was as high as 150 degreeC or more, a mode that copper was oxidized red by heating at the time of sample shaping | molding was observed.

As a result of measuring the adhesive strength of the sample piece after the wet heat test using the same method, Examples 5, 15, and 17 to 17 containing a polyisocyanate having a biuret structure or a nurate structure as the second component. Samples 18, 22, 24-26, and 29 all obtained results of 0.5 N / mm ² or more, and in particular, Example 18 in which the second component contains a polyisocyanate having a nurate structure, 22 and 26 are more preferable because the rate of decrease in the adhesive strength after the wet heat test is small. On the other hand, Comparative Examples 6 to 9 all show a value of 0.2 N / mm ² or less, and the adhesiveness is remarkably lowered even when compared with the value before the wet heat test. In particular, in Comparative Examples 6, 8, and 9, the bonded portion was detached during the wet heat test, and the adhesive force was 0 N / mm ² . In addition, a state in which a part of copper turns blue-green is observed, which may be caused by the presence of the acid of the reaction residue in the resin.

  From the above results, the thermally conductive resin of the present invention can be bonded to a base material such as copper without causing damage due to heat or reaction residues, and has excellent adhesion to a metal such as copper. It was suggested that In addition, since the adhesiveness is maintained even in a high temperature and high humidity environment, it can be applied to various uses.

<Evaluation of hardness>
Hardness was measured for the heat conductive resin compositions of Examples 17 to 23 using a rubber / plastic hardness meter GS-701N (manufactured by Tecrock Co., Ltd.). The measuring method is based on SRIS 0101. Table 12 shows the hardness of each sheet. The measurement at a temperature of 50 ° C. was carried out using a sheet placed on a hot plate set at 52 ° C., and the same operation as the normal measurement was performed.

  Examples 17 to 23 in Table 12 have a hardness at 50 ° C. of ASKER C 95 or less, which is preferable because followability to irregularities such as a metal surface can be obtained by appropriate flexibility and thermal resistance is lowered. In addition, Examples 17 to 19, 21, and 22 are more preferable because the hardness at a temperature of 25 ° C. is ASKER C 80 or more and the hardness at 50 ° C. is ASKER C 60 or more, and the adhesive strength can be maintained. Thus, since the hardness of the resin composition after hardening can be adjusted according to a use, maintaining the outstanding heat conductivity of a resin composition, it is preferable.

DESCRIPTION OF SYMBOLS 1 Thermal conductive sheet containing aggregate of boron nitride scale-like particles 2 Thermal conductive sheet containing boron nitride scale-like particles 11 Aggregate 12 Resin 13 Scaled particles of boron nitride 21 Metal member 22 Electronic component

Claims (17)

A first component containing an inorganic filler that is an aggregate (III) of liquid polyol (I) and boron nitride scaly particles;
A second component comprising polyisocyanate (II);
Two-component heat conductive resin composition. The polyol (I) includes at least one polycarbonate polyol,
The composition of claim 1. The polyol (I) contains at least one polycarbonate diol,
The composition according to claim 2. The polyisocyanate (II) includes at least one non-yellowing polyisocyanate,
The composition according to any one of claims 1 to 3. The polyisocyanate (II) has a biuret structure, an adduct structure, a nurate structure, or an allophanate structure.
The composition according to claim 4. The polyisocyanate (II) includes a plurality of types of polyisocyanates, and includes a biuret structure, a nurate structure, or both structures.
The composition according to claim 4. The polyisocyanate (II) contains hexamethylene diisocyanate as an isocyanate species,
The composition according to any one of claims 4 to 6. The boron nitride scaly particle aggregate (III) is a ratio of 40 vol% or less of the total amount of the liquid polyol (I), polyisocyanate (II), and boron nitride scaly particle aggregate (III). Including
The composition according to any one of claims 1 to 7. The first component further includes at least one additional filler selected from the group consisting of boron nitride, silica, alumina, aluminum nitride, cordierite, mullite, titanium oxide, zinc oxide, silicon carbide, diamond, and graphite. ,
The composition according to any one of claims 1 to 8. The additional filler is at least one selected from the group consisting of the aluminum nitride and the boron nitride,
The boron nitride is a boron nitride whisker,
The aluminum nitride is an aluminum nitride whisker.
The composition according to claim 9. The additional filler is at least one selected from the group consisting of the boron nitride, the alumina, and the aluminum nitride,
The boron nitride is scale-like,
The alumina is spherical,
The aluminum nitride is spherical.
The composition according to claim 9. The boron nitride scaly particle aggregate (III) and the additional filler are powders,
The average particle diameter of the aggregate (III) of the scale-like particles of boron nitride is 10 to 500 μm,
The average particle size of the boron nitride scaly particles is 1 to 50 μm,
The average particle diameter of the spherical alumina and the spherical aluminum nitride is 1 to 200 μm.
The composition of claim 11. The mass ratio of the aggregate mass (III) of the boron nitride scale-like particles and the scale-like particles of boron nitride to the total mass of the spherical alumina and the spherical aluminum nitride was 60: 40-5. : 95,
The composition according to claim 11 or 12. It consists of the hardened | cured material of the two-component type heat conductive resin composition of any one of Claims 1-13.
Thermal conductive sheet. It is in the form of a sheet and has a thickness of 5 to 1000 μm.
The heat conductive sheet according to claim 14. A metal member;
The heat conductive sheet according to claim 14 or 15, which covers the metal member.
Metal products. A metal member;
With electronic components:
The heat conductive sheet according to claim 14 or 15, sandwiched between the metal member and the electronic component.
Electronics.

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