JP2015010200A - Thermally conductive deformable aggregate, thermally conductive resin composition, thermally conductive member, and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermally conductive member having high thermal conductivity and excellent film-formability and substrate followability, and a thermally conductive resin composition for producing an adhesive sheet excellent in heat resistance.SOLUTION: An easily deformable aggregate (D) contains 100 pts.wt of thermally conductive particles (A) having an average primary particle size of 0.1-10 μm, and 0.1-30 pts.wt of an organic binder (B) having a reactive functional group; and has an average particle size of 2-100 μm, and an average compressive force required for a compression deformation rate of 10% of 5 mN or less.

Description

  The present invention relates to a thermally conductive deformable aggregate, a thermally conductive resin composition, a thermally conductive member, and a method for producing the same, which can be suitably used for forming a thermally conductive member for releasing heat of an electronic device.

In recent years, the development of the electronics field has been remarkable, and in particular, electronic devices have become smaller, lighter, higher density, and higher in output, and demands for these performances have become increasingly sophisticated. High insulation and reliability are required to reduce the size and density of electronic circuits, and in particular, there is a strong need to improve heat dissipation to prevent deterioration of electronic devices due to heat generated by higher output of electronic devices. ing.
In the electronics field, a polymer material is suitably used as an insulating material, and in order to improve heat dissipation, it has been desired to improve the thermal conductivity of the polymer material. However, since there is a limit to improving the thermal conductivity of the polymer material, a method has been developed to improve heat dissipation by mixing thermally conductive particles with the polymer material. In recent years, the use as a heat conductive adhesive sheet obtained by molding them into a sheet shape or a pressure sensitive adhesive sheet has been studied.

For example, Patent Document 1 discloses a molding resin containing a nanocomposite polyamide resin in which a layered silicate is uniformly dispersed and a thermally conductive inorganic filler. As the thermally conductive inorganic filler, aluminum oxide, magnesium oxide, silica, zinc oxide, boron nitride, silicon carbide, silicon nitride and the like are disclosed.
Thermally conductive inorganic fillers are required to have improved thermal conductivity so that the molded body can be imparted with thermal conductivity with a smaller amount than in the past.

Patent Document 2 obtains spherical composite particles having an average particle diameter of 3 to 85 μm and improved thermal conductivity by granulating and sintering high thermal conductivity particles having an average particle diameter of 10 μm or less. The use of the composite particles has been proposed.
Specifically, after thermally conductive particles such as aluminum oxide, aluminum nitride, and crystalline silica are coated with a silane coupling agent or a thermosetting resin, at least 800 ° C., usually 1000 to 2800 ° C. A method of obtaining spherical composite particles by sintering at a temperature close to the melting point of the heat conductive particles has been proposed (see [0009], [0021] to “0022”, [0028] to [0032]).
According to Patent Document 2, it is disclosed that sintering is performed in order to increase the cohesive force of the composite particles. However, as a result of sintering at a temperature close to the melting point of the thermally conductive particles after granulation, the binder used during granulation disappears, and the cohesive force of the composite particles after sintering is never high, rather it is sintered. The later composite particles are brittle, cannot maintain a granulated state, and are easily disintegrated.
Alternatively, if the sintering is sufficiently performed at a temperature equal to or higher than the melting point, the heat conductive particles are fused and integrated, so that a high cohesive force can be obtained. However, as a result of the fusion integration, huge hard particles are formed.

  Patent Document 3 includes a powder composition comprising an inorganic powder such as aluminum oxide, magnesium oxide, boron nitride, and aluminum nitride and a thermosetting resin composition, and processed into a powder, a granulated powder, and a granular state. Use is proposed. However, since the inorganic powder used in this method is large in size and uses a thermosetting resin composition, the resin hardens in the aggregate, so that a hard powder with strong bonds can be obtained. It is a body composition.

  Patent Document 4 discloses a composite particle powder obtained by coating the surface of an aluminum oxide particle powder with a surface modifier and then attaching a carbon powder to the surface modifier-coated particle surface in a nitrogen atmosphere at 1350 to 1750 ° C. Discloses a method for producing aluminum nitride that is heated and calcined at (see claims, [0034], [0042], [0046] to [0049]).

Patent Document 5 discloses a spherical aluminum nitride sintered powder having an average particle size of 10 to 500 μm and a porosity of 0.3% or more. Specifically, a slurry containing an aluminum nitride powder containing 10% by weight or more of a powder having a primary particle size of 0.1 to 0.8 μm and a sintering aid such as lithium oxide or calcium oxide is spray-dried, Furthermore, the manufacturing method of the said spherical aluminum nitride sintered powder baked at 1400-1800 degreeC is described (refer Claim 1, 4, [0035]).
In the case of Patent Documents 4 and 5, as in the case of Patent Document 2, since sintering is performed at a very high temperature and the sintering aid or the like and aluminum nitride are strongly bonded to each other, an aggregate is obtained. For example, hard aluminum nitride, or huge and hard aluminum nitride particles integrated by sintering.

Patent Document 6 discloses the use of secondary agglomerated particles obtained by isotropically agglomerating primary particles of scaly boron nitride.
Specifically, after calcining scaly boron nitride at around 1800 ° C., granules formed from pulverized primary particles are fired at 2000 ° C., the porosity is 50% or less, and the average pore diameter is 0. A method for obtaining a secondary aggregate of 0.05 to 3 μm has been disclosed (see [0014], [0026] and “0027]).

  Patent Document 7 discloses the use of a spherical boron nitride aggregate obtained by aggregating irregularly shaped non-spherical boron nitride particles.

  Patent Document 8 discloses the use of a silicon nitride sintered body, and Patent Document 9 discloses the use of a spherical zinc oxide particle powder obtained by sintering.

On the other hand, as a heat conductive member using heat conductive particles, for example, Patent Documents 10 and 11 disclose heat conductive adhesive sheets using inorganic particles. In order to increase the thermal conductivity of these thermally conductive members, it is effective to increase the packing rate of the particles. However, as the amount of particles increases, the polymer material component decreases. Decrease in material followability occurs. Moreover, especially in the adhesive sheet use, there existed a subject that an adhesive component will reduce by raising a filling rate, and adhesiveness will be lost.

Therefore, as in Patent Documents 12 and 13, there is a method for controlling the orientation of particles by applying a magnetic field or an electric field to a thermally conductive member in order to form contact (heat transfer path) of particles with a low particle filling rate. It has been reported. However, these methods are not practical when considering industrialization.

Further, Patent Document 14 reports an attempt to form a tertiary aggregate in which secondary particles are arranged close to each other in a coating film and to exhibit high thermal conductivity with a low filling amount. In this report as well, a silane coupling agent is used as a binder for granulation, and the secondary particles are dried at 150 ° C. for 4 hours or more and subjected to a coupling reaction, thereby producing a granulated product. While improving operability, the flexibility of the particles is lost. Therefore, both thermal conductivity and adhesive strength are insufficient.

Thus, the heat conductive resin composition and the heat conductive sheet using the conventional heat conductive particles and the secondary particles (aggregates) thereof have high heat conductivity and excellent film formability, It has been difficult to achieve substrate followability and adhesion.

JP 2006-342192 A JP-A-9-59425 JP 2000-239542 A JP 2006-256940 A JP 2006-206393 A JP 2010-157563 A Japanese translation of PCT publication No. 2008-510878 Japanese Patent Laid-Open No. 2007-039306 JP 2009-249226 A JP-A-6-162855 JP 2004-217861 A JP 2006-335957 A JP 2007-332224 A JP 2010-84072 A

  The object of the present invention is to produce a thermally conductive easily deformable aggregate or a thermally conductive member having high thermal conductivity, excellent film formability and substrate followability, and an adhesive sheet having excellent heat resistance. Therefore, it is providing the heat conductive resin composition.

The present invention comprises 100 parts by weight of spherical heat conductive particles (A) having an average primary particle size of 0.1 to 10 μm,
Including 0.1 to 30 parts by weight of an organic binder (B) having a reactive functional group,
The present invention relates to an easily deformable aggregate (D) characterized by having an average particle diameter of 2 to 100 μm and an average compressive force required for a compression deformation rate of 10% of 5 mN or less.

The present invention also relates to the easily deformable aggregate (D), wherein the thermally conductive particles (A) contain at least one selected from the group consisting of aluminum oxide and aluminum nitride.

Moreover, this invention contains the said easily deformable aggregate (D) 20-90 volume%, binder resin (E) 10-80 volume%, and the solvent (F) which melt | dissolves binder resin (E). And relates to a thermally conductive resin composition (G).

Moreover, this invention relates to the said heat conductive resin composition (G) in which the organic binder (B) which has the reactive functional group which comprises an easily deformable aggregate (D) does not melt | dissolve in a solvent (F). .

In the present invention, the organic binder (B) having a reactive functional group constituting the easily deformable aggregate (D) is a water-soluble resin, and the binder resin (E) is a water-insoluble resin. It is related with the said heat conductive resin composition (G).

Moreover, this invention relates to the heat conductive member (H) containing the heat conductive layer by which a solvent (F) is removed from the said heat conductive resin composition (G).

Moreover, this invention relates to the heat conductive member (I) formed by pressurizing and heating the said heat conductive member (H).

Moreover, this invention contains the said heat conductive member (H) or the said heat conductive member (I),
The present invention relates to a thermally conductive adhesive sheet having a release film on at least one surface.

Further, the present invention is a method for producing the easily deformable aggregate (D),
100 parts by mass of spherical heat conductive particles (A) having an average primary particle size of 0.1 to 10 μm, 0.1 to 30 parts by mass of an organic binder (B) having a reactive functional group, and a reactive functional group A step of obtaining a slurry containing a solvent (C) for dissolving the organic binder (B) having,
And a step of removing the solvent (C) from the slurry.

Further, the present invention includes a step of applying the thermal conductive resin composition (G) on a substrate to form a coating film,
Removing the solvent (F) from the coating film to form a heat conductive layer;
It is related with the manufacturing method of heat conductive member (I) which has the process of pressurizing the said heat conductive layer.

The easily deformable aggregate of the present invention imparts the same thermal conductivity to the heat conductive member with a smaller amount of use, or a higher heat conductivity with the same amount of the conventional heat conductive member. The heat conductive easily deformable aggregate for providing to can be provided.
In addition, since the thermally conductive member of the present invention uses an easily deformable aggregate having high thermal conductivity, the thermally conductive member having high thermal conductivity, excellent film formability, and substrate followability, and Furthermore, it is possible to provide a heat conductive resin composition for producing an adhesive sheet having excellent heat resistance.

Thermally conductive particles (A) having an average primary particle size of 1 μm, thermal conductive particles (A) having an average primary particle size of 10 μm, and thermal conductive particles (A) having an average primary particle size of 1 μm It is a figure which shows the relationship between a compressive deformation rate and compressive force of the easily deformable aggregate (D) with an average particle diameter of 10 micrometers aggregated with the organic binder (B) which has a group. The SEM photograph of the heat conductive particle (A) whose average primary particle diameter is 1 micrometer. Thermosetting containing an easily deformable aggregate (D) having an average particle diameter of 10 μm obtained by aggregating thermally conductive particles (A) having an average primary particle diameter of 1 μm with an organic binder (B) having a reactive functional group SEM photograph of the plane of the adhesive sheet. The SEM photograph of the plane of the hardened | cured material which heat-cured the thermosetting sheet of FIG. 3a under pressure. The SEM photograph of the cross section of the hardened | cured material which heat-cured the thermosetting sheet of FIG. 3a under pressure. The SEM photograph of the heat conductive particle (A) with an average primary particle diameter of 10 micrometers.

  The easily deformable aggregate (D) of the present invention comprises an organic binder (B) having 100 parts by weight of spherical heat conductive particles (A) having an average primary particle size of 0.1 to 10 μm and a reactive functional group. ) 0.1 to 30 parts by weight, the average particle size is 2 to 100 μm, and the average compressive force required for a compression deformation rate of 10% is 5 mN or less.

The “easy deformability” in the present invention means that an average compressive force required for a compression deformation rate of 10% is 5 mN or less. The average compressive force required for a compressive deformation rate of 10% is an average value of a load for deforming particles by 10% measured by a compression test. For example, a micro compression tester (manufactured by Shimadzu Corporation, MCT -210).
Specifically, a very small amount of sample to be measured is magnified with a microscope, an arbitrary one is selected, the particles to be measured are moved to the lower part of the pressure indenter, a load is applied to the pressure indenter, The measurement target particles are compressed and deformed. The tester includes a detector for measuring a compression displacement of the measurement target particle on an upper portion of the pressurizing indenter. The detector measures the compression displacement of the particles to be measured, and obtains the deformation rate. Then, the compression force required for 10% compression deformation of the particles to be measured (hereinafter also abbreviated as “10% compression deformation force”) is obtained. Similarly, “10% compressive deformation force” is obtained for any other particles to be measured, and the average value of “10% compressive deformation force” for 10 particles to be measured is “average required for 10% compression deformation rate”. Compressive force ".
The easily deformable aggregate (D) of the present invention is a state in which a plurality of small heat conductive particles (A) are aggregated as will be described later. The unit of

FIG. 1 shows a non-aggregated thermally conductive particle (A) as shown in FIGS. 2 and 4 and an easily deformable aggregate (D) in which the thermally conductive particles (A) as shown in FIG. 2 are aggregated. It is a figure which shows the relationship between the compression deformation rate and compressive force about). The size of the easily deformable aggregate (D) is approximately the same as the size of the thermally conductive particles (A) shown in FIG.
As shown in FIG. 1, the heat conductive particles (A) that are not aggregated require a large force to be deformed only slightly. On the other hand, when the thermally conductive particles (A) having the same size as that of FIG. 2 are aggregated to the same size as the thermally conductive particles (A) of FIG. 4, as shown in FIG. Can be deformed.
That is, the aggregate (D) of the present invention is an “easily deformable” aggregate.
FIG. 3a is a SEM photograph of a plane of a thermosetting sheet which is a kind of a heat conductive precursor member containing the aggregate (D) of the present invention, and FIG. 3b is a heat cure of the heat conductive precursor member under pressure. Fig. 3c is a SEM photograph of a cross section of the cured product. 3a, b, and c also confirm that the aggregate (D) of the present invention is an “easy deformable” aggregate.
The reason why the aggregate (D) of the present invention is excellent in thermal conductivity because it is “easy to deform” will be described later.

<Thermal conductive particles (A)>
Thermally conductive particles (A) are not particularly limited as long as they have thermal conductivity. For example,
Metal oxides such as aluminum oxide, calcium oxide, magnesium oxide,
Metal nitrides such as aluminum nitride and boron nitride,
Metal hydroxides such as aluminum hydroxide and magnesium hydroxide,
Metal carbonates such as calcium carbonate and magnesium carbonate,
Silicate metal salts such as calcium silicate,
Hydrated metal compounds,
Crystalline silica, amorphous silica, silicon carbide or a composite thereof,
Metals such as gold and silver,
Examples thereof include carbon compounds such as carbon black.
These may be used alone or in combination of two or more.

When used in electronic circuit applications, it is preferable to have insulating properties, and metal oxides and metal nitrides are preferably used. Of these, aluminum oxide, aluminum nitride, and boron nitride are more preferable from the viewpoint of thermal conductivity. Preferably used.
When the easily deformable aggregate (D) to be obtained is used for an electronic material application or the like, the thermally conductive particles (A) are more preferably aluminum oxide that is not easily hydrolyzed.
Moreover, if metal nitrides, such as aluminum nitride which performed the process for improving hydrolysis resistance previously, are used and an easily deformable aggregate (D) is obtained, the easily deformable aggregate (D) obtained will be obtained. Can also be used for electronic materials.

The thermally conductive particles (A) are preferably spherical in view of the small number of voids and ease of deformation in the resulting easily deformable aggregate (D).
When spherical particles are used, a dense easily deformable aggregate (D) with few voids can be obtained. Since the voids in the easily deformable aggregate (D) deteriorate the thermal conductivity, it is important in terms of improving the thermal conductivity to prevent the voids from being generated as much as possible.
Moreover, when the heat conductive particles (A) are spherical, the coefficient of friction between the particles of the heat conductive particles (A) in the aggregate is small. As a result, when a force is applied to the aggregate, the positional relationship of the heat conductive particles (A) in the aggregate easily changes, and the aggregate is easily deformed without collapsing.
When comparing the composition of the thermally conductive particles and the particles having the same average primary particle size, when using non-spherical particles such as plate-like or needle-like particles, compared to using spherical particles, relatively voids In many cases, the friction between the constituent particles in the aggregate is relatively large and the aggregate tends to be relatively difficult to deform.

In the present invention, the term “spherical” refers to, for example, “circularity”. The circularity is an arbitrary number of particles selected from a photograph of the particles taken with an SEM or the like, and represents the area of the particles. When S and the perimeter are L, it can be expressed as (circularity) = 4πS / L ² . In order to measure the circularity, various image processing software or an apparatus equipped with image processing software can be used. In the present invention, flow type particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics Co., Ltd. is used. The average circularity when the average circularity of the particles is measured is 0.9 to 1. Preferably, the average circularity is 0.96-1.

The heat conductive particles (A) used for obtaining the easily deformable aggregate (D) have an average primary particle diameter of 0.1 to 10 μm, and preferably 0.3 to 10 μm. When using one type of thermally conductive particles (A), it is preferable to use particles having an average primary particle size of 0.3 to 5 μm. A plurality of types of thermally conductive particles (A) having different sizes can also be used, and in that case, using a combination of relatively small and relatively large particles reduces the porosity in the aggregate. This is preferable.
If the average primary particle size is too small, the number of contacts between the primary particles in the aggregate increases, and the contact resistance increases, so the thermal conductivity tends to decrease. On the other hand, if the average primary particle size is too large, it tends to collapse even if an aggregate is prepared, and the aggregate itself is difficult to be formed.
In addition, the average primary particle diameter of the heat conductive particles (A) in the present invention is a value when measured with a particle size distribution meter (for example, Mastersizer 2000, manufactured by Malvern Instruments).
In addition, the easily deformable aggregate (D) of the present invention is less likely to collapse. For example, the easily deformable aggregate (D) is placed in a glass sample tube so as to have a porosity of 70%, and is shaken. Even if it shakes for 2 hours, it is supported also because the average particle diameter after shaking is 80% or more of the average particle diameter before shaking.

<Organic binder (B) having a reactive functional group>
The organic binder (B) having a reactive functional group in the present invention plays a role of “tethering” for binding the heat conductive particles (A) to each other. In addition, a reactive functional group in the organic binder (B) reacts with a functional group in the binder resin (E) described later, whereby a thermal conductive layer of the thermal conductive members (H) and (I) described later. The internal cross-linking structure develops, leading to improved heat resistance.
The reactivity referred to here forms a cross-linked structure with a functional group of the binder resin (E) described later by heating the thermally conductive members (H) and (I) containing the aggregate (D) of the present invention. It shows that. Therefore, it is preferable that the heating step is performed simultaneously with or after the heat conductive members (H) and (I) are pressurized and the aggregate (D) is deformed. For example, it is not preferable to have a functional group that exhibits reactivity before being subjected to compression deformation, such as reactivity at 25 ° C., because the deformability of the easily deformable aggregate (D) is impaired.

  The organic binder (B) having a reactive functional group is not particularly limited as long as it has a functional group reactive with the functional group in the binder resin (E). Further, the molecular weight is not limited as long as it can play the role of “tethering”.

Examples of the reactive functional group include an epoxy group, a carboxyl group, an acetoacetyl group, an amino group, an isocyanate group, a hydroxyl group, and a thiol group. The functional group can be used alone or in combination of two or more.
The organic binder (B) having a reactive functional group may be a resin synthesized using a monomer having a reactive functional group, or a part of a resin having no reactive functional group may be modified. Further, a functional group having reactivity may be added.

As the organic binder (B) having a reactive functional group, for example,
Hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, carboxymethylethylcellulose, carboxymethylnitrocellulose, polyvinyl alcohol, ethylene / vinyl alcohol resin, styrene / maleic anhydride resin, vinyl chloride / vinyl acetate / male Examples thereof include acid resins, maleic resins, melamine resins, polyallylamine, polyacrylic acid, epoxy resins, and those obtained by further introducing reactive functional groups.
Polyether resins, polyurethane resins, (unsaturated) polyester resins, alkyd resins, butyral resins, acetal resins, polyamide resins, (meth) acrylic resins, styrene / (meth) acrylic resins, polystyrene resins, nitrocellulose, benzylcellulose , Cellulose (tri) acetate, casein, shellac, gelatin, gilsonite, rosin, rosin ester, polyvinylpyrrolidone, polyacrylamide, methylcellulose, ethylcellulose, polybutadiene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinylidene fluoride resin, polyacetic acid Vinyl resin, ethylene / vinyl acetate resin, vinyl chloride / vinyl acetate resin, fluorine resin, silicon resin, phenoxy resin, phenol resin, urea resin, benzoguana Down resin, ketone resin, petroleum resin, chlorinated polyolefin resin, a modified chlorinated polyolefin resin, and chlorinated polyurethane resins include those obtained by introducing a reactive functional group.

The organic binder (B) having a reactive functional group is preferably carboxymethylcellulose, polyvinyl alcohol, polyacrylic acid, an epoxy resin, and those obtained by further introducing a reactive functional group into these resins.
Moreover, the organic binder (B) which has a reactive functional group may be used individually by 1 type, or may be used in mixture of 2 or more types.

When the functional group in the binder resin (E) is an epoxy group, examples of the functional group of the organic binder (B) include an epoxy group, a carboxyl group, an acetoacetyl group, an amino group, a hydroxyl group, and a thiol group. However, the functional group is not limited thereto.

When the functional group in the binder resin (E) is a carboxyl group, examples of the functional group of the organic binder (B) include an epoxy group, an acetoacetyl group, an amino group, an isocyanate group, a hydroxyl group, and a thiol group. However, the functional group is not limited thereto.

When the functional group in the binder resin (E) is an acetoacetyl group, examples of the functional group of the organic binder (B) include an epoxy group, a carboxyl group, an amino group, an isocyanate group, a hydroxyl group, and a thiol group. However, the functional group is not limited thereto.

When the functional group in the binder resin (E) is an amino group, examples of the functional group of the organic binder (B) include functional groups such as an epoxy group, a carboxyl group, an acetoacetyl group, and an isocyanate group. However, it is not limited to this.

When the functional group in the binder resin (E) is an isocyanate group, examples of the functional group of the organic binder (B) include a functional group such as a carboxyl group, an acetoacetyl group, an amino group, a hydroxyl group, and a thiol group. However, it is not limited to this.

When the functional group in the binder resin (E) is a hydroxyl group, examples of the functional group of the organic binder (B) include a functional group such as an epoxy group, a carboxyl group, an acetoacetyl group, and an isocyanate group. However, it is not limited to this.

When the functional group in the binder resin (E) is a thiol group, examples of the functional group of the organic binder (B) include functional groups such as an epoxy group, a carboxyl group, an acetoacetyl group, and an isocyanate group. However, it is not limited to this.

From the viewpoint of heat resistance, the reactive functional group of the organic binder (B) is an epoxy group, an acetoacetyl group, an amino group, a hydroxyl group, or a carboxyl group, and the functional group in the binder resin (E) is an epoxy group, A carboxyl group, a hydroxyl group, or an acetoacetyl group is preferable.

Moreover, it is preferable that the organic binder (B) which has a reactive functional group is insoluble in a solvent (F). The term “insoluble” as used herein means that when 1 g of an organic binder (B) having a reactive functional group is placed in 100 g of a solvent (F) and stirred at 25 ° C. for 24 hours, precipitation is visually confirmed. Say.
Since the organic binder (B) having a reactive functional group plays a role of “tethering” for binding the thermally conductive particles, the thermally conductive resin composition is insoluble in the solvent (F). This is because the easily deformable aggregate (D) can maintain the aggregated state.

The organic binder (B) having a reactive functional group is preferably a water-soluble resin. When the heat conductive member (I) described later is an adhesive sheet, it can be suitably used. The term “water-soluble” as used herein means that precipitation is not visually confirmed when 1 g of resin is added to 100 g of water and stirred at 25 ° C. for 24 hours.
The water-soluble resin is not particularly limited, and examples thereof include polyvinyl alcohol, carboxymethyl cellulose, polyallylamine, and those obtained by further introducing a reactive functional group into these resins.

  The easily deformable aggregate (D) of the present invention contains 0.1 to 30 parts by weight of the organic binder (B) having the reactive functional group with respect to 100 parts by weight of the heat conductive particles (A). It is preferable to contain 1-10 weight part. If the amount is less than 0.1 part by weight, the heat conductive particles (A) cannot be sufficiently bound, and a sufficient strength for maintaining the form cannot be obtained. When the amount is more than 30 parts by weight, the effect of binding the thermally conductive particles (A) is increased, but the binder enters between the thermally conductive particles (A) more than necessary, and the thermal conductivity. It is not preferable because there is a possibility of hindering.

2-100 micrometers is preferable and, as for the average particle diameter of the easily deformable aggregate (D) of this invention, More preferably, it is 5-50 micrometers. When the average particle diameter is smaller than 2 μm, the number of the heat conductive particles (A) constituting the aggregate (D) is decreased, the effect as the aggregate is low, and the deformability is inferior. When the average particle diameter exceeds 100 μm, the weight of the easily deformable aggregate (D) per unit volume increases, and the degree of freedom in the film thickness of the highly thermally conductive member that settles or forms when used as a dispersion. This is not preferable because problems such as disappearance occur.
In addition, the average particle diameter of the easily deformable aggregate (D) in the present invention is a value when measured with a particle size distribution meter (for example, Mastersizer 2000 manufactured by Malvern Instruments).

The specific surface area of the easily deformable aggregate (D) is not particularly limited, but is preferably 10 m ² / g or less, and more preferably 5 m ² / g or more. When it is larger than 10 m ² / g, the binder resin (E) is adsorbed on the particle surface or inside the agglomerates, and tends to decrease film formability and adhesive strength, which is not preferable.

The specific surface area is a value measured by a BET specific surface area meter (for example, BELSORP-mini manufactured by Nippon Bell Co., Ltd.).

<Manufacturing method>
The easily deformable aggregate (D) of the present invention includes, for example, an organic binder having 100 parts by weight of spherical thermally conductive particles (A) having an average primary particle size of 0.1 to 10 μm and a reactive functional group ( B) A slurry containing 0.1 to 30 parts by weight and a solvent (C) that dissolves the organic binder (B) having the reactive functional group is obtained, and then the solvent (C) is obtained from the slurry. It can be obtained by removing.
Alternatively, it is obtained by mixing 100 parts by weight of the heat conductive particles (A) and 0.1 to 30 parts by weight of the organic binder (B) having a reactive functional group, or the heat conductive particles (A) 100. The organic binder (B) having a reactive functional group (0.1 to 30 parts by weight) and a solvent (C) for dissolving the organic binder (B) having the reactive functional group are contained in parts by weight. It can also be obtained by removing the solvent (C) after or while spraying the organic binder solution.
In order to obtain an easily deformable aggregate (D) having a uniform composition, the heat conductive particles (A) and the organic binder (B) having a reactive functional group are mixed in advance in the solvent (C). It is preferable to go through a step of making a slurry and then remove the solvent (C).

The solvent (C) is for dissolving the thermally conductive particles (A) and dissolving the organic binder (B) having a reactive functional group.
The solvent (C) is not particularly limited as long as it can dissolve the organic binder (B) having a reactive functional group, and is appropriately selected depending on the type of the organic binder (B) having a reactive functional group. be able to. As the solvent (C), for example, ester solvents, ketone solvents, glycol ether solvents, aliphatic solvents, aromatic solvents, alcohol solvents, ether solvents, water and the like can be used. A mixture of more than one can also be used.

The solvent (C) preferably has a lower boiling point from the viewpoint of easy removal, and preferably has a boiling point of 110 ° C. or lower, such as water, ethanol, methanol, ethyl acetate, or the like.
Further, the amount of the solvent (C) used is preferably small in terms of ease of removal, but it is adjusted according to the solubility of the organic binder (B) having a reactive functional group and the drying apparatus. It can be changed as appropriate.

The method for removing the solvent (C) from the slurry is not particularly limited, and the easily deformable aggregate (D) can be produced using a commercially available apparatus. For example, it can be selected from methods such as spray drying, stirring drying, and stationary drying. Among them, spray drying can be suitably used from the viewpoint that a relatively round and easily deformable aggregate (D) having a uniform particle diameter can be obtained with high productivity.
Specifically, the solvent (C) may be volatilized and removed while spraying the slurry in the form of a mist. Spray conditions and volatilization conditions can be selected as appropriate.

<Thermal conductive resin composition (G), thermal conductive member (H), (I)>
The heat conductive resin composition (G) preferably contains an easily deformable aggregate (D), a binder resin (E), and a solvent (F), and the easily deformable aggregate (D) is 20 to 90% by volume. More preferably, the binder resin (E) is contained in an amount of 10 to 80% by volume and the solvent (F) for dissolving the binder resin (E).

A thermally conductive resin composition (G) is applied onto a substrate to form a coating film, and the solvent (F) is removed from the coating film to form a thermally conductive layer. H) can be obtained.
Furthermore, the heat conductivity which improved the heat conductivity of the heat conductive member (H) by applying a pressure to the heat conductive member (H), and deforming the easily deformable aggregate (D) contained. A member (high thermal conductivity member) (I) can be obtained.
Further, at the same time as or after the deformable aggregate (D) is deformed, heat is applied to the heat conductive member (H) to crosslink the organic binder (B) and the binder resin (E). By doing, the heat resistance of the said heat conductive member (H) can be improved.

For example, a heat conductive sheet is obtained as the heat conductive member (H) using the heat conductive resin composition (G), and the pressure and heat are applied by sandwiching the heat conductive sheet between the article to be radiated and the heat radiating member. By adding, a heat conductive sheet with improved heat conductivity and heat resistance can be obtained as the heat conductive member (I). This heat conductive sheet can efficiently transmit the heat of the object to be radiated to the heat radiating member.
As the heat conductive member (H), a heat conductive sheet having adhesiveness or tackiness can be obtained. In this case, the article to be radiated and the radiating member can be bonded together at the time of pressurization.

By applying pressure and heat to the thermally conductive resin composition (G) and deforming the easily deformable aggregate (D) contained therein, the sheet-like thermally conductive member (I) can be obtained directly. it can.

As an article for heat dissipation,
Various electronic components such as integrated circuits, IC chips, hybrid packages, multi-modules, power transistors and LED (light emitting diode) substrates;
Examples include articles that are used in building materials, vehicles, aircraft, ships, and the like, are easily heated, and need to release the heat to the outside in order to prevent performance deterioration.

In order to achieve high thermal conductivity, it is important to form more heat conduction paths in the direction in which heat is to be transmitted.
In the easily deformable aggregate (D) of the present invention, since the heat conductive particles (A) are aggregated, the distance between the particles is close and the heat conduction path is formed in advance, so that the heat conduction is efficiently performed. be able to.
In addition, since the easily deformable aggregate (D) of the present invention is “easy to deform”, high thermal conductivity can be realized. That is, when a force is applied to the easily deformable aggregate (D), the easily deformable aggregate (D) does not collapse, and the heat conductive particles (A) in the easily deformable aggregate (D) are not separated. By improving the adhesion, a previously formed heat conduction path can be enhanced. In addition, since the position of the thermally conductive particles (A) constituting the easily deformable aggregate (D) can be easily changed, the easily deformable aggregate (D) is formed between the heat radiation target article and the heat dissipation member. Follows the shape of the interface, the contact area between the heat radiation target article or heat radiating member and the heat conductive particles (A) increases, and the heat inflow area and the heat propagation path can be dramatically increased.

Further details will be described with reference to the drawings.
FIG. 3a is an easily deformable material having an average particle diameter of 10 μm obtained by aggregating the heat conductive particles (A) having an average primary particle diameter of 1 μm shown in FIG. 2 with an organic binder (B) having a reactive functional group. It is an example of the SEM surface photograph of the thermosetting sheet containing an aggregate (D). 3b and 3c are a SEM plane photograph and a SEM sectional photograph of a cured product obtained by thermosetting the thermosetting sheet of FIG. 3a under pressure.
By applying pressure to the thermosetting sheet, the thermally conductive particles (A) in the easily deformable aggregate (D) are more closely adhered to each other, and more thermally conductive particles (A) are present on the surface of the cured product. It can be confirmed that the shape of the interface is followed.
On the other hand, non-aggregated thermally conductive particles (A) as shown in FIG. 4 having the same size as the easily deformable aggregate (D) shown in FIG. Since it does not have deformability, the above change can hardly be confirmed before and after pressurization of the thermosetting sheet.
Thus, since the easily deformable aggregate (D) of the present invention is “easy to deform”, it has excellent thermal conductivity. That is, the easily deformable aggregate (D) of the present invention imparts the same thermal conductivity to the heat conductive member with a smaller amount of use, or higher heat with the same amount of the conventional one. Conductivity can be imparted to the thermally conductive member.

The thermal conductivity (W / m · K) is the thermal diffusivity (mm ² / s) representing the rate at which heat is conducted through the sample, and the specific heat capacity (J / (g · K)) and density (g / cm ³ ) and obtained by the following formula.
Thermal conductivity (W / m · K) = thermal diffusivity (mm ² / s) × specific heat capacity (J / (g · K)) × density (g / cm ³ )

For the measurement of the thermal diffusivity, for example, a periodic heating method, a hot disk method, a temperature wave analysis method, a flash method, or the like can be selected according to the shape of the measurement sample. In the data described herein, the thermal diffusivity was measured by a flash method using a Xenon flash analyzer LFA447 NanoFlash (manufactured by NETZSCH).

<Binder resin (E)>
The binder resin (E) used when obtaining the heat conductive resin composition is not particularly limited as long as it can form a heat conductive member and has a functional group that reacts with the organic binder (B). For example,
Polyurethane resin, polyester resin, polyester urethane resin, alkyd resin, butyral resin, acetal resin, polyamide resin, acrylic resin, styrene-acrylic resin, styrene resin, nitrocellulose, benzylcellulose, cellulose (tri) acetate, casein, shellac, gilsonite , Gelatin, styrene-maleic anhydride resin, polybutadiene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinylidene fluoride resin, polyvinyl acetate resin, ethylene vinyl acetate resin, vinyl chloride / vinyl acetate copolymer resin, vinyl chloride / Vinyl acetate / maleic acid copolymer resin, fluorine resin, silicone resin, epoxy resin, phenoxy resin, phenol resin, maleic acid resin, urea resin, melamine resin, benzoguanami Resin, ketone resin, petroleum resin, rosin, rosin ester, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, ethylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, carboxymethylethylcellulose, carboxymethyl One or more selected from the group consisting of nitrocellulose, ethylene / vinyl alcohol resin, polyolefin resin, chlorinated polyolefin resin, modified chlorinated polyolefin resin, and chlorinated polyurethane resin can be used as appropriate. .
Among these, epoxy resins are preferably used from the viewpoints of insulation and heat resistance when used as urethane resins and electronic parts from the viewpoint of flexibility.
The binder resin (E) contained in the thermally conductive resin composition (G) or the thermally conductive member (H) is a binder resin (E) that cures itself or reacts with an appropriate curing agent. Can be used.

Examples of the functional group that the binder resin (E) has include an epoxy group, a carboxyl group, an acetoacetyl group, an ester group, an amino group, an isocyanate group, a hydroxyl group, and a thiol group. The functional group can be used alone or in combination of two or more.

The binder resin (E) is preferably a water-insoluble resin. The term “water-insoluble” as used herein means that precipitation is visually confirmed when 1 g of resin is put into 100 g of water and stirred at 25 ° C. for 24 hours. Specifically, the resin has the reactive functional group. Examples other than the water-soluble resin in the organic binder (B) are mentioned.
The binder resin (E) is preferably a water-insoluble resin when imparting adhesiveness to the heat conductive member (I) described later.

<Solvent (F)>
The solvent (F) is used for uniformly dispersing the easily deformable aggregate (D) and the binder resin (E) in the thermally conductive resin composition (G).

The solvent (F) used can dissolve the binder resin (E) and does not dissolve the organic binder (B) having a reactive functional group constituting the easily deformable aggregate (D). It is important to select as appropriate. When the heat conductive resin composition (G) is obtained, if a solvent (F) that dissolves the organic binder (B) having a reactive functional group is used, the aggregation state of the easily deformable aggregate (D) Can not be held.
For example, when a water-soluble resin such as polyvinyl alcohol, polyallylamine, or carboxymethylcellulose is selected as the organic binder (B) having a reactive functional group, the solvent for obtaining the heat conductive resin composition (G) As (F), a non-aqueous solvent such as toluene or xylene may be selected.
When a water-insoluble resin such as phenoxy resin or petroleum resin is selected as the organic binder (B) having a reactive functional group, the solvent (F) for obtaining the heat conductive resin composition (G) An aqueous solvent such as water or alcohol may be selected.
Here, “insoluble” means that 1 g of the organic binder (B) having a reactive functional group is put in 100 g of the solvent (F), stirred at 25 ° C. for 24 hours, and precipitation is confirmed visually. I will do it.

The content of the easily deformable aggregate (D) in the thermally conductive resin composition (G) can be appropriately selected according to the target thermal conductivity and application, but in order to obtain high thermal conductivity. Is preferably 20 to 90% by volume based on the solid content of the thermally conductive resin composition (G). More preferably, it is in the range of 30 to 80% by volume.
If the content is less than 20% by volume, the effect of adding the easily deformable aggregate (D) is thin and sufficient thermal conductivity cannot be obtained. On the other hand, when it exceeds 90% by volume, the content of the binder resin (E) is relatively reduced, and the formed heat conductive member (H) and the heat conductive member (I) become brittle, or the heat conductive member. There is a possibility that voids may be formed in (I), and there is a possibility that the thermal conductivity gradually decreases while using the thermal conductive member (I). The volume% here means the heat conductive particles (A) with respect to the solid content in the heat conductive resin composition (G), the organic binder (B) having a reactive functional group, and the binder resin (E). The theoretical values calculated based on the weight ratio and specific gravity are shown.

  The easily deformable aggregate (D) may be used alone, or may have a different average particle size, a different type of heat conductive particles (A) or a different average primary particle size, or may be configured. A plurality of organic binders (B) having different types and amounts of reactive functional groups may be used in combination.

Moreover, the heat conductive resin composition (G) can also use together the heat conductive particle which has not aggregated. By also using thermally conductive particles that are not agglomerated, the gap between the easily deformable aggregates (D) is filled, or when the easily deformable aggregates (D) are deformed, heat conduction is caused. The gap between the conductive particles (A) can be filled, and further improvement in thermal conductivity can be expected.
Examples of the thermally conductive particles that can be used in combination include those exemplified as the thermally conductive particles (A).

Moreover, you may add other fillers, such as a flame retardant, to a heat conductive resin composition (G) further as needed.
Although it does not specifically limit as a flame retardant, For example, aluminum hydroxide, magnesium hydroxide, etc. are mentioned.

Various additives can be added to the heat conductive resin composition (G) as necessary. Examples of the various additives include a coupling agent for improving the adhesion to the substrate, an ion scavenger for increasing the insulation reliability at the time of moisture absorption, a leveling agent, and a curing agent for enhancing the heat resistance. These may use 1 type and can also use multiple types together.
The organic binder is preferably reacted with not only the binder resin but also the curing agent because the heat resistance is improved.

<Manufacturing method>
The heat conductive resin composition (G) is preferably produced by stirring and mixing the easily deformable aggregate (D), the binder resin (E), and the solvent (F). Common stirring methods can be used for stirring and mixing, for example, scandex, paint conditioner, sand mill, rake machine, medialess disperser, three rolls, bead mill, etc. Can do.

  After stirring and mixing, it is preferable to go through a defoaming step in order to remove bubbles from the heat conductive resin composition (G). The method of defoaming is not particularly limited and can be performed using a general method, and examples thereof include vacuum defoaming and ultrasonic defoaming.

The manufacturing method of the heat conductive member (H) of the present invention is:
Applying a thermally conductive resin composition (G) on a substrate to form a coating film;
Removing the solvent (F) from the coating film to form a heat conductive layer.

The method for producing the heat conductive member (I) of the present invention comprises:
Preparing a thermally conductive member (H);
And pressurizing the heat conductive layer.

As the heat conductive members (H) and (I), a heat conductive sheet or the like can be manufactured. A heat conductive sheet may be called a heat conductive film.

Examples of the substrate include plastic films such as polyester film, polyethylene film, polypropylene film, and polyimide film;
and,
A film obtained by releasing the plastic film (hereinafter referred to as a release film);
Examples thereof include metal bodies or metal foils such as aluminum, copper, stainless steel, and beryllium copper.

Examples of the method for applying the thermally conductive resin composition (G) to the substrate include knife coating, die coating, lip coating, roll coating, curtain coating, bar coating, gravure coating, flexographic coating, dip coating, spray coating, and screen. Examples thereof include a coat and a spin coat.

The thickness of the heat conductive layer can be appropriately determined according to the application.
In applications such as a heat conductive sheet, which is disposed between a heat source and a heat sink and used to release heat, the thickness of the heat conductive layer is usually 10 to 200 μm from the viewpoint of heat conductivity and various physical properties, The thickness is preferably 30 to 150 μm. In addition, in applications such as a housing such as a package in which heat from a heat source is not trapped, the thickness of the heat conductive layer can be set to 200 μm or more, and in some cases, about 1 mm in view of strength and the like. .

After the heat conductive layer (H) is manufactured by forming a heat conductive layer on an arbitrary base material, another arbitrary base material is stacked, and press-pressed under heating, and the heat conductive member (I) is Can be obtained.
At least one of the two substrates can be a release film. In this case, the release film can be peeled off.
When two base materials are used as release films, the two release films are peeled off to isolate the heat conductive layer, which can be used as the heat conductive member (I).

The pressure press processing method is not particularly limited, and a known press processing machine can be used.
Although the temperature at the time of pressurization can be selected suitably, if it uses as a thermosetting adhesive sheet, it is desirable to heat above the temperature which the thermosetting of binder resin (E) occurs.
If necessary, it can be pressed under reduced pressure.
The pressure at the time of pressing can be appropriately selected as long as a pressure capable of deforming the easily deformable aggregate (D) can be applied, but is preferably 1 MPa or more.

By directly molding the heat conductive resin composition (G) containing no solvent (F) under pressure, a highly heat-conductive molded product can be obtained.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, a following example does not restrict | limit the right range of this invention at all. In Examples, “parts” and “%” respectively represent “parts by weight” and “% by weight” unless otherwise specified, “vol%” represents “volume%”, and Mw represents a weight average molecular weight. Represent.
The average primary particle size, circularity, average particle size, average compressive force required for a compression deformation rate of 10%, resistance to collapse, and the like were determined as follows.

<Average primary particle size>
It measured using the particle size distribution meter master sizer 2000 by Malvern Instruments. The measurement conditions were a dry unit and an air pressure of 2.5 bar, and the feed rate was optimized by the sample.

<Circularity>
The average circularity of the particles was measured using a flow type particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics Co., Ltd. Specifically, about 5 mg of particles to be measured are dispersed in 10 ml of toluene to prepare a dispersion, and the dispersion is irradiated with ultrasonic waves (20 kHz, 50 W) for 5 minutes. The dispersion concentration is 5,000 to 20,000 / The measurement was performed with the above apparatus as μl, and the circularity of the circle-equivalent diameter particle group was measured to obtain the average circularity.

<Average particle size>
It measured using the particle size distribution meter master sizer 2000 by Malvern Instruments. The measurement conditions were a dry unit and an air pressure of 2.5 bar, and the feed rate was optimized by the sample.

<Average compression force required for 10% compression deformation>
The average compressive force required for a compressive deformation rate of 10% was a random compression tester (manufactured by Shimadzu Corporation, MCT-210), and a load for deforming particles by 10% was randomly selected within the measurement region. It measured about the particle | grains and made it the average value.

<Difficult to collapse: maintenance ratio of average particle diameter after shaking test>
The easily deformable aggregate (D) is put in a glass sample tube so as to have a porosity of 70%, shaken with a shaker for 2 hours, and then the particle size distribution is measured. It was confirmed using 80% or more of the average particle diameter as an index.

<Resin synthesis example 1>
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dripping device, and a nitrogen introduction tube, a polyester polyol obtained from terephthalic acid, adipic acid and 3-methyl-1,5-pentanediol (Kuraray Co., Ltd. Polyol P-1011 ", Mn = 1006) 401.9 parts by weight, 12.7 parts by weight of dimethylolbutanoic acid, 151.0 parts by weight of isophorone diisocyanate, 40.0 parts by weight of toluene were charged at 90 ° C under a nitrogen atmosphere. It was made to react for time, and 300.0 weight part of toluene was added to this, and the urethane prepolymer solution which has an isocyanate group was obtained.
Next, 27.8 parts by weight of isophorone diamine, 3.2 parts by weight of di-n-butylamine, 342.0 parts by weight of 2-propanol, and 396.0 parts by weight of toluene have the obtained isocyanate group. Add 815.1 parts by weight of urethane prepolymer solution, react at 70 ° C. for 3 hours, dilute with 144.0 parts by weight of toluene and 72.0 parts by weight of 2-propanol, Mw = 54,000, acid value = 8 mgKOH / G polyurethane polyurea resin solution E-1 was obtained.

<Resin synthesis example 2>
In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, dropping device, introduction tube, and nitrogen introduction tube, 292.1 parts by weight of polycarbonate diol (Kuraray polyol C-2090: manufactured by Kuraray Co., Ltd.), tetrahydrophthalic anhydride (Licacid TH: manufactured by Shin Nippon Rika Co., Ltd.) 44.9 parts by weight and 350.0 parts by weight of toluene as a solvent were charged, and the mixture was heated to 60 ° C. with stirring in a nitrogen stream, and dissolved uniformly. Subsequently, the flask was heated to 110 ° C. and reacted for 3 hours. Then, after cooling to 40 ° C., 62.9 parts by weight of bisphenol A type epoxy resin (YD-8125: manufactured by Tohto Kasei Co., Ltd.) and 4.0 parts by weight of triphenylphosphine as a catalyst were added, and the temperature was raised to 110 ° C. , Reacted for 8 hours. After cooling to room temperature, the solid content was adjusted to 35% with toluene to obtain a carboxyl group-containing modified ester resin E-2 solution having Mw = 25000.

<Resin synthesis example 3>
A four-necked flask equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping funnel was charged with 98.5 parts by weight of butyl acrylate, 1.5 parts by weight of acrylic acid, and 150.0 parts by weight of ethyl acetate. The mixture was heated to 70 ° C. under substitution, and 0.15 parts by weight of azobisisobutyronitrile was added to initiate polymerization. 0.13 parts by weight of azobisisobutyronitrile was added for another 2 hours from 3 hours after the start of polymerization until 5 hours after every other hour. Thereafter, 150.0 parts by weight of ethyl acetate was added to terminate the polymerization, and an acrylic resin E-3 having a solid content of 25% and Mw = 84000 was obtained.

<Example of easily deformable aggregate (D)>
Example 1
Aluminum oxide particles (“AO-502” manufactured by Admatechs Co., Ltd., average primary particle size: about 1 μm, average circularity: 0.99): 100 parts by mass, carboxymethyl cellulose (“CMC Daicel 1240” manufactured by Daicel Finechem Co., Ltd.) 4 mass% aqueous solution: 125 mass parts (solid content: 5 mass parts) and ion-exchange water: 25 mass parts were stirred with a disper at 1000 rpm for 1 hour to obtain a slurry.
This slurry is spray-dried in a mini-spray dryer (“B-290” manufactured by Nihon Büch Co., Ltd.) in an atmosphere of 125 ° C., and an average compression force required for an average particle diameter of about 10 μm and a compression deformation rate of 10%: about 3. An easily deformable aggregate (D-1) having a maintenance rate of 2 mN and an average particle diameter after the shaking test of 98% was obtained.

(Example 2)
Aluminum oxide particles (“CB-P02” manufactured by Showa Denko KK, average primary particle size: about 2 μm, average circularity: 0.98): 100 parts by mass, modified vinyl alcohol having an acetoacetyl group (Nippon Synthetic Chemical Industry Co., Ltd.) A 4% by weight aqueous solution of the company “Goseifamer Z-100”): 50 parts by mass (solid content: 2 parts by mass) and ion-exchanged water: 100 parts by mass An easily deformable aggregate (D-2) having an average particle size of about 15 μm, an average compression force required for a compression deformation rate of 10%: about 0.3 mN, and an average particle size maintenance rate after shaking test of 93% was obtained. .

Example 3
Aluminum oxide particles (“AO-509” manufactured by Admatechs Co., Ltd., average primary particle size: about 10 μm, average circularity: 0.99): 100 parts, modified vinyl alcohol having an acetoacetyl group (Nippon Synthetic Chemical Industry Co., Ltd.) Example 1 except that 42.5% aqueous solution: 12.5 parts by mass (solid content: 0.5 parts by mass) and ion-exchanged water: 137.5 parts by mass were used. In the same manner as above, an easily deformable aggregate (D-3) having an average particle diameter of about 40 μm, an average compression force required for a compression deformation ratio of 10%: about 1 mN, and an average particle diameter maintenance ratio after a shaking test of 92% Got.

Example 4
Aluminum nitride (“H grade” manufactured by Tokuyama Corporation, average primary particle size: about 1 μm, average circularity: 0.97): 100 parts by mass, modified polyvinyl alcohol having an acetoacetyl group (manufactured by Nippon Synthetic Chemical Industry Co., Ltd. “ Average particle size in the same manner as in Example 1 except that 4% by weight aqueous solution of Goosephemer Z-100 "): 50 parts by mass (solid content: 2 parts by mass) and ion-exchanged water: 100 parts by mass were used. An easily deformable aggregate (D-4) having an average compression force of about 15 μm, an average compression force required for a compression deformation rate of 10%: about 0.7 mN, and an average particle diameter maintenance rate after a shaking test of 92% was obtained.

(Example 5)
Aluminum oxide particles (“CB-P05” manufactured by Showa Denko KK, average primary particle size: about 5 μm, average circularity: 0.99): 100 parts by mass, 40% by mass aqueous solution of polyacrylic acid with Mw = 25000: 12 0.5 parts by mass (solid content: 10 parts by mass) and ion-exchanged water: an average required for an average particle size of about 30 μm and a compression deformation rate of 10% in the same manner as in Example 1 except that 137.5 parts by mass were used. An easily deformable aggregate (D-5) having a compressive force of about 2 mN and an average particle size retention rate after shaking test of 95% was obtained.

(Example 6)
Instead of the 4% by mass aqueous solution of carboxymethylcellulose in Example 1, an epoxy resin composition (manufactured by Japan Epoxy Resin, “Epicoat 1010”, 2 parts by mass, and toluene: 148 parts by mass was used, and the spray drying temperature was 125 ° C. to 140 ° C. Except for changing to ° C., in the same manner as in Example 1, the average particle size is about 20 μm, the average compression force required for the compression deformation rate is 10%: about 0.4 mN, the maintenance rate of the average particle size after the shaking test: 93 % Easily deformable aggregate (D-6) was obtained.

(Example 7)
After obtaining the same slurry as in Example 1, it was dried with stirring in a high speed mixer ("LFS-2" manufactured by Earth Technica Co., Ltd.) to remove moisture, and the average particle size was about 100 µm, and the compression deformation rate was 10 Average compressive force required for%: about 3 mN, an easily deformable aggregate (D-7) having an average particle diameter retention rate after shaking test of 90% was obtained.

(Comparative Example 1)
Instead of “CB-P02”, aluminum oxide particles (“CB-A20S” manufactured by Showa Denko KK, average primary particle size: about 20 μm, average circularity: 0.98, average compressive force required for compression deformation rate of 10% : About 220 mN), an attempt was made to obtain an easily deformable aggregate using the 4% by mass aqueous solution of the above carboxymethylcellulose with respect to the aluminum oxide particles in the same manner as in Example 1. The product (D'-1) which does not constitute a state was obtained.

(Comparative Example 2)
An attempt was made to obtain an easily deformable aggregate in the same manner as in Example 1 except that carboxymethylcellulose was not used and the ion-exchanged water was changed to 150 parts by mass, but it was easily disintegrated and did not form an aggregate. The product (D′-2) was obtained.

(Comparative Example 3)
The average particle diameter was about 20 μm, and the compressive deformation rate was the same as in Example 1 except that the 4% by mass aqueous solution of carboxymethylcellulose was 1250 parts by mass (solid content: 50 parts by mass) and the ion-exchanged water was 50 parts by mass. An easily deformable aggregate (D′-3) having an average compressive force required for 10% of about 0.8 mN and an average particle diameter maintenance rate after a shaking test of 12% was obtained.

(Comparative Example 4)
A silane coupling agent ("KBM-04" manufactured by Shin-Etsu Chemical Co., Ltd.), tetramethoxysilane (10 mass% solution): 20 mass parts (solid content: 2 mass parts) is used without using a 4 mass% aqueous solution of carboxymethylcellulose. A slurry was obtained in the same manner as in Example 1 except that the ion-exchanged water was changed to 130 parts by mass. An easily deformable aggregate (D′-4) having an average compressive force required: about 42 mN and an average particle diameter maintenance rate after the shaking test of 75% was obtained.

(Comparative Example 5)
A slurry similar to that of Comparative Example 4 was obtained. This slurry was spray-dried in an atmosphere of 125 ° C., and then sintered at 2100 ° C., which is equal to or higher than the melting point of aluminum oxide. An easily deformable aggregate (D′-5) having an average compressive force of about 200 mN and an average particle diameter retention rate after shaking test of 98% was obtained.

(Comparative Example 6)
Of 100 parts by mass of aluminum oxide particles (Sumitomo Chemical Co., Ltd., “AL-33”, average primary particle size: about 12 μm, average circularity: 0.9), polyurethane resin (Toyobo Co., Ltd .: Byron UR-1400) 20 mass% toluene solution: 10 mass parts (solid content: 2 mass parts) is used, and an easily deformable aggregate is obtained in the same manner as in Example 1 except that 140 mass parts of toluene is used instead of ion-exchanged water. However, a product (D′-6) that was easily disintegrated and did not form an aggregate was obtained.

Table 1 shows main production conditions and evaluation results in Examples 1 to 7 and Comparative Examples 1 to 6.

  As shown in Table 1, in order to produce an aggregate, the average primary particle diameter of the heat conductive particles (A) is 10 μm or less, and it is necessary to use an organic binder (B). Comparative Examples 1, 2, and 6 cannot form an aggregate. As shown in Comparative Example 3, when the amount of the organic binder (B) is too large, the aggregates are further aggregated when shaken, and are deteriorated by impact. As shown in Comparative Examples 4 and 5, a silane coupling agent is used as an organic binder, and the easily deformable aggregate (D) is heated and cured before being deformed, or baked at a temperature higher than the melting point of aluminum oxide. For example, if the heat conductive particles (A) are firmly bonded to each other, the easily deformable property becomes poor.

<Examples of thermally conductive resin composition (G) and thermally conductive members (H) and (I)>
(Example 8)
37.1 parts by mass of easily deformable aggregate (D-1) (average particle size 10 μm) obtained in Example 1 and 30% toluene of the polyurethane polyurea resin (E-1) obtained in Resin Synthesis Example 1 Disperse stirring 31.5 parts by mass of 2-propanol solution and 3.15 parts by mass of 50% MEK solution of bisphenol A type epoxy resin (“Epicoat 1001” manufactured by Japan Epoxy Resin Co., Ltd.), 2-propanol 6.5 After adjusting the viscosity with parts by mass and 25.8 parts by mass of toluene, ultrasonic degassing was performed to obtain a thermally conductive resin composition having a content of easily deformable aggregates of 50 vol%.
The obtained thermally conductive resin composition was applied to a release-treated sheet (a release-treated polyethylene terephthalate film having a thickness of 75 μm) using a comma coater, dried by heating at 100 ° C. for 2 minutes, and the thickness of the thermally conductive layer Obtained the heat conductive member (H-1) of 50 micrometers. The thermal conductivity was 3 (W / m · K). By pressing this heat conductive member (H-1) at 150 ° C. and 2 MPa for 1 hour, the heat conductive member (I) having a heat conductive layer thickness of 45 μm and a heat conductivity of 7 (W / m · K). -1) was obtained.
Separately, the heat treatment layer (P-1) is separated from the heat conductive member (H-1) to isolate the heat conductive layer, which is sandwiched between a 40 μm thick copper foil and a 250 μm thick aluminum plate, at 150 ° C. and 2 MPa. Pressed for 1 hour. The obtained sheet had good heat resistance.

Example 9
37.1 parts by mass of the easily deformable aggregate (D-2) (average particle size 15 μm) obtained in Example 2 and 30% toluene of the polyurethane polyurea resin (E-1) obtained in Resin Synthesis Example 1 Disperse stirring of 31.5 parts by mass of 2-propanol solution and 3.15 parts by mass of 50% MEK solution of Epicoat 1031S (manufactured by Japan Epoxy Resin Co., Ltd.) as a curing agent, 6.5 parts by mass of 2-propanol And after adjusting a viscosity with 25.8 mass parts of toluene, it ultrasonically defoamed and obtained the heat conductive resin composition of 70 vol% of content rate of an easily deformable aggregate.
Using the obtained heat conductive resin composition, in the same manner as in Example 8, a heat conductive member (H-2) having a heat conductive layer thickness of 65 μm and a heat conductivity of 2.8 (W / m · K). ) Further, similarly, a heat conductive member (I-2) having a heat conductive layer thickness of 60 μm, a heat conductivity of 5.5 (W / m · K), and good heat resistance was obtained.

(Example 10)
Of the easily deformable aggregate (D-3) (average particle size 40 μm) obtained in Example 3, 32.4 parts by mass and the carboxyl group-containing modified ester resin (E-2) obtained in Resin Synthesis Example 2 36.0 parts by mass of a 35% toluene solution and 2.5 parts by mass of Chemite PZ (manufactured by Nippon Shokubai Co., Ltd.) as a curing agent were mixed and stirred with a disper, 9.3 parts by mass of 2-propanol and 37.0 parts of toluene. After adjusting the viscosity with parts by mass, ultrasonic degassing was performed to obtain a thermally conductive resin composition with a content of easily deformable aggregates of 40 vol%.
Using the obtained heat conductive resin composition, a heat conductive member (H-3) having a heat conductive layer thickness of 60 μm and a heat conductivity of 2.5 (W / m · K) was obtained in the same manner as in Example 8. ) Further, similarly, a heat conductive member (I-3) having a heat conductive layer thickness of 55 μm, a heat conductivity of 3.5 (W / m · K), and good heat resistance was obtained.

(Example 11)
36.0 parts by mass of the easily deformable aggregate (D-4) (average particle size 15 μm) obtained in Example 4 and 25% ethyl acetate of the acrylic resin (E-3) obtained in Resin Synthesis Example 3 After mixing 50.4 parts by mass of the solution and 1 part by mass of Chemite PZ (manufactured by Nippon Shokubai Co., Ltd.) as a thermosetting aid, stirring the dispersion, adjusting the viscosity with 29.0 parts by mass of methyl ethyl ketone (MEK), Ultrasonic defoaming was performed to obtain a thermally conductive resin composition having a content of easily deformable aggregates of 50 vol%.
Using the obtained heat conductive resin composition, a heat conductive member (H-4) having a heat conductive layer thickness of 50 μm and a heat conductivity of 6 (W / m · K) was obtained in the same manner as in Example 8. Obtained. Similarly, a heat conductive member (I-4) having a heat conductive layer thickness of 44 μm, a heat conductivity of 10 (W / m · K), and good heat resistance was obtained.

(Example 12)
25% toluene solution of easily deformable aggregate (D-5) (average particle size 30 μm) 22.8 parts by mass obtained in Example 5 and epoxy resin (YX-4000H, manufactured by Yuka Shell Epoxy Co., Ltd.) 68.8 parts by mass and 1.72 parts by mass of Chemite PZ (manufactured by Nippon Shokubai Co., Ltd.) as a thermosetting aid are mixed and stirred with a disper, and after adjusting the viscosity with 11.0 parts by mass of toluene, ultrasonic waves By defoaming, a thermally conductive resin composition having a content of easily deformable aggregates of 25 vol% was obtained.
Using the obtained thermal conductive resin composition, in the same manner as in Example 8, the thermal conductive member (H-5) having a thermal conductive layer thickness of 50 μm and a thermal conductivity of 2.3 (W / m · K). ) Further, similarly, a heat conductive member (I-5) having a heat conductive layer thickness of 45 μm, a heat conductivity of 3 (W / m · K), and good heat resistance was obtained.

(Example 13)
38.3 parts by mass of easily deformable aggregate (D-6) (average particle size 20 μm) obtained in Example 6 and aqueous emulsion resin (Polysol AX-590, Showa Denko KK, solid content 49%) After mixing with 13.8 parts by mass and stirring with a disper, adjusting the viscosity with 48.0 parts by mass of water, ultrasonically defoaming to obtain a thermally conductive resin composition having a content of easily deformable aggregates of 60 vol%. Obtained.
Using the obtained heat conductive resin composition, in the same manner as in Example 8, a heat conductive member (H-6) having a heat conductive layer thickness of 50 μm and a heat conductivity of 2 (W / m · K) was obtained. Obtained. Further, similarly, a heat conductive member (I-6) having a heat conductive layer thickness of 45 μm, a heat conductivity of 4.2, and good heat resistance was obtained.

(Example 14)
The easily deformable aggregate (D-7) obtained in Example 7 (D-7) (average particle size 100 μm) 61.6 parts by mass, polyester urethane resin Byron UR6100 (manufactured by Toyobo Co., Ltd.) 18.7 parts by mass, as a curing agent Epoxy curing agent Tetrad X (manufactured by Mitsubishi Gas Chemical Co., Inc.) of 0.08 parts by mass with Disper stirring, and after adjusting the viscosity with 20.0 parts by mass of toluene, ultrasonically degassed and easily deformable aggregates A heat conductive resin composition having a content of 65 vol% was obtained.
Using the obtained heat conductive resin composition, in the same manner as in Example 8, the heat conductive member (H-7) having a heat conductive layer thickness of 110 μm and a heat conductivity of 2.7 (W / m · K). ) Similarly, a heat conductive member (I-7) having a heat conductive layer thickness of 100 μm, a heat conductivity of 5 (W / m · K), and good heat resistance was obtained.

(Comparative Example 7)
36.0 parts by mass of spherical aluminum oxide powder having an average primary particle diameter of 1 μm (manufactured by Admatechs Co., Ltd., AO-502) and 25% toluene / polyurethane polyurea resin (E-1) obtained in Resin Synthesis Example 1 Disperse agitation of 36.0 parts by mass of 2-propanol solution and 3.6 parts by mass of 50% MEK solution of bisphenol A type epoxy resin Epicoat 1001 (manufactured by Japan Epoxy Resin Co., Ltd.) as a curing agent. After adjusting the viscosity with 0.7 parts by mass and 22.7 parts by mass of toluene, ultrasonic degassing was performed to obtain a resin composition with an aluminum oxide content of 50 vol%.
Using the obtained resin composition, a comma-coater was used to coat a release-treated sheet (a release-treated polyethylene terephthalate film having a thickness of 75 μm), followed by heating and drying at 100 ° C. for 2 minutes. The thickness of the heat conductive layer was 50 μm. A heat conductive member (H′-1) having a heat conductivity of 0.5 (W / m · K) was obtained. Further, a release treatment sheet was stacked on this heat conductive member (H′-1) and pressed at 150 ° C. and 2 MPa for 1 hour to obtain a heat conductive member (I′-1) having a thickness of 45 μm. The thermal conductivity of this sheet was as low as 0.8 (W / m · K).
Separately, the release treatment sheet is peeled from the heat conductive member (H′-1) to isolate the heat conductive layer, which is sandwiched between a 40 μm thick copper foil and a 250 μm thick aluminum plate, and 150 ° C., 2 MPa. And pressed for 1 hour. In the obtained sample, peeling was observed in a heat resistance test.

(Comparative Example 8)
36.0 parts by mass of spherical aluminum oxide powder (CB-A20S, manufactured by Showa Denko KK) having an average primary particle size of 20 μm and 25% toluene / polyurethane polyurea resin (E-1) obtained in Resin Synthesis Example 1 Disperse agitation of 36.0 parts by mass of 2-propanol solution and 3.6 parts by mass of 50% MEK solution of bisphenol A type epoxy resin Epicoat 1001 (manufactured by Japan Epoxy Resin Co., Ltd.) as a curing agent. After adjusting the viscosity with 0.7 parts by mass and 22.7 parts by mass of toluene, ultrasonic degassing was performed to obtain a resin composition with an aluminum oxide content of 50 vol%.
Using the obtained resin composition, a heat conductive member (H′-2) having a heat conductive layer thickness of 50 μm and a heat conductivity of 0.4 (W / m · K) was obtained in the same manner as in Comparative Example 7. Obtained. Similarly, a heat conductive member (I′-2) having a thickness of 45 μm, a heat conductivity of 0.7 (W / m · K), and a slight foaming observed in a heat resistance test was obtained.

(Comparative Example 9)
38.3 parts by mass of the aggregate (D′-3) (average particle size 20 μm) obtained in Comparative Example 3 and 25% toluene / 2 of the polyurethane polyurea resin (E-1) obtained in Resin Synthesis Example 1 Disperse stirring 27.0 parts by mass of a propanol solution and 2.7 parts by mass of a 50% MEK solution of bisphenol A type epoxy resin Epicoat 1001 (manufactured by Japan Epoxy Resin Co., Ltd.) as a curing agent. After adjusting the viscosity with 0 part by mass and 28.0 parts by mass of toluene, ultrasonic degassing was performed to obtain a resin composition having an aggregate content of 60 vol%.
Using the obtained resin composition, a heat conductive member (H′-3) having a heat conductive layer thickness of 60 μm and a heat conductivity of 0.3 (W / m · K) is obtained in the same manner as in Comparative Example 7. Obtained. Further, similarly, a heat conductive member (I′-3) having a thickness of 50 μm, a thermal conductivity of 0.4 (W / m · K), and good heat resistance was obtained.

(Comparative Example 10)
Aggregate (D′-4) (average particle diameter 15 μm) 38.3 parts by mass obtained in Comparative Example 4 and 25% toluene / 2 of the polyurethane polyurea resin (E-1) obtained in Resin Synthesis Example 1 Disperse stirring 27.0 parts by mass of a propanol solution and 2.7 parts by mass of a 50% MEK solution of bisphenol A type epoxy resin Epicoat 1001 (manufactured by Japan Epoxy Resin Co., Ltd.) as a curing agent. After adjusting the viscosity with 0 part by mass and 28.0 parts by mass of toluene, ultrasonic degassing was performed to obtain a resin composition having an aggregate content of 60 vol%.
Using the obtained resin composition, a heat conductive member (H′-4) having a heat conductive layer thickness of 60 μm and a heat conductivity of 0.2 (W / m · K) was obtained in the same manner as in Comparative Example 7. Obtained. Further, similarly, a heat conductive member (I′-4) having a thickness of 50 μm, a heat conductivity of 0.4 (W / m · K), and peeling observed in a heat resistance test was obtained.
In this sheet, many cracks due to the crushed particles were observed.

(Comparative Example 11)
38.3 parts by mass of (D′-5) prepared in Comparative Example 5 and 27.0 parts by mass of a 35% toluene solution of the carboxyl group-containing modified ester resin (E-2) obtained in Resin Synthesis Example 2, Disperse stirring 2.7 parts by mass of 50% MEK solution of bisphenol A type epoxy resin Epicoat 1001 (manufactured by Japan Epoxy Resin Co., Ltd.) as a curing agent, 7.0 parts by mass of 2-propanol and 28.0 parts by mass of toluene After adjusting the viscosity with, ultrasonic defoaming was performed to obtain a resin composition having a non-aggregate content of 60 vol%.
Using the obtained resin composition, in the same manner as in Comparative Example 7, a heat conductive member (H′-5) having a heat conductive layer thickness of 60 μm and a heat conductivity of 0.7 (W / m · K) was obtained. Obtained. Similarly, a heat conductive member (I′-5) having a thickness of 50 μm, a heat conductivity of 0.9 (W / m · K), and peeling observed in a heat resistance test was obtained.
In this sheet, many cracks due to the crushed particles were observed.

Table 2 shows main production conditions and evaluation results in Examples 8 to 14 and Comparative Examples 7 to 11. Only the solvent (F) in the table was added as a solvent.

<Calculation method of thermal conductivity>
A sample sample was cut into a 15 mm square, and the sample surface was gold-deposited and carbon-coated with carbon spray, and then the thermal diffusivity in a sample environment at 25 ° C. was measured with a xenon flash analyzer LFA447 NanoFlash (manufactured by NETZSCH). The specific heat capacity was measured using a high-sensitivity differential scanning calorimeter DSC220C manufactured by SII Nano Technology. Furthermore, the density was calculated using an underwater substitution method.

<Testing method for heat resistance>
A sample having a three-layer structure (copper foil (40 μm) / high thermal conductivity member / aluminum plate (250 μm)) was floated for 3 minutes by bringing the aluminum plate surface into contact with 260 ° C. molten solder. Thereafter, the external appearance of the sample was visually observed, and the state of occurrence of foaming, floating / peeling of the high thermal conductive member was evaluated.
Foaming is a state in which bubbles are generated at the interface between the high thermal conductive member and the copper foil (40 μm).
Floating / peeling refers to a state in which a three-layered sample that has been brought into close contact with the aluminum plate or copper foil has been lifted off. The evaluation results are shown in Table 2.
Each evaluation standard is as follows.
A: No change in appearance.
○: Small foaming is slightly observed.
Δ: Foaming is observed.
X: Vigorous generation and peeling are observed.

  As shown in Table 2, the thermally conductive resin composition (G) of the present invention provides the thermally conductive member (H) or (I) excellent in thermal conductivity. As shown in Comparative Examples 7 and 8, a resin composition containing no easily deformable aggregate (D) in the thermally conductive resin composition (G) cannot exhibit sufficient thermal conductivity. As shown in Comparative Example 9, even when the aggregate is broken during resin composition production, the resin content is large, so there is no sufficient heat conduction path, and high heat conductivity cannot be expressed. As shown in Comparative Example 10, since the deformability of the easily deformable aggregate (D) is impaired when an organic binder (B) having a reactive functional group that exhibits reactivity before being compressed and deformed, Sufficient thermal conductivity may not be obtained. As shown in Comparative Example 11, when the sintering is performed at a temperature equal to or higher than the melting point of aluminum oxide, the deformability of the easily deformable aggregate (D) is impaired, so that sufficient thermal conductivity cannot be obtained. Moreover, as shown in Comparative Examples 10 and 11, if the reactive functional group in the organic binder reacts with the functional group of the binder resin (E) before forming a crosslinked structure, sufficient heat resistance is obtained. I can't get it.

Claims (10)

100 parts by weight of spherical thermally conductive particles (A) having an average primary particle size of 0.1 to 10 μm,
Including 0.1 to 30 parts by weight of an organic binder (B) having a reactive functional group,
An easily deformable aggregate (D) having an average particle diameter of 2 to 100 μm and an average compressive force required for a compression deformation rate of 10% of 5 mN or less.   The easily deformable aggregate (D) according to claim 1, wherein the thermally conductive particles (A) contain at least one selected from the group consisting of aluminum oxide and aluminum nitride.   The easily deformable aggregate (D) according to claim 1 or 2, comprising 20 to 90% by volume, 10 to 80% by volume of the binder resin (E), and a solvent (F) for dissolving the binder resin (E). Thermally conductive resin composition (G). The thermally conductive resin composition (G) according to claim 3, wherein the organic binder (B) having a reactive functional group constituting the easily deformable aggregate (D) is not dissolved in the solvent (F). The organic binder (B) having a reactive functional group constituting the easily deformable aggregate (D) is a water-soluble resin, and the binder resin (E) is a water-insoluble resin. Thermally conductive resin composition (G). The heat conductive member (H) containing the heat conductive layer by which a solvent (F) is removed from the heat conductive resin composition (G) in any one of Claims 3-5.   The heat conductive member (I) formed by pressurizing and heating the heat conductive member (H) according to claim 6. The heat conductive member (H) according to claim 6, or the heat conductive member (I) according to claim 7,
A thermally conductive adhesive sheet having a release film on at least one surface. It is a manufacturing method of the easily deformable aggregate (D) of any one of Claim 1 or 2,
100 parts by mass of spherical heat conductive particles (A) having an average primary particle size of 0.1 to 10 μm, 0.1 to 30 parts by mass of an organic binder (B) having a reactive functional group, and a reactive functional group A step of obtaining a slurry containing a solvent (C) for dissolving the organic binder (B) having,

A process for removing the solvent (C) from the slurry, and a method for producing the easily deformable aggregate (D).
Applying the thermally conductive resin composition (G) according to any one of claims 3 to 5 on a substrate to form a coating film;
Removing the solvent (F) from the coating film to form a heat conductive layer;
A method for producing a thermally conductive member (I), comprising a step of pressurizing the thermally conductive layer.