JP2021125687A - Thermally conductive sheet and manufacturing method thereof, and heat dissipation part and manufacturing method thereof - Google Patents

Abstract

To provide a thermally conductive sheet superior in handleability and heat resistance independently of the flexibility of a thermally conductive sheet body, etc.SOLUTION: A thermally conductive sheet is to be used in the state of being interposed between an electronic part and a radiator. The thermally conductive sheet comprises: a thermally conductive sheet body containing a thermally conductive filler; an adhesive layer disposed in contact with a first face of the thermally conductive sheet body on the whole surface; a peeling film disposed on a face of the adhesive layer on a side opposite to a thermally conductive sheet body-side face; and a protection film disposed in contact with a second face of the thermally conductive sheet body on a side opposite to the first face on the whole surface, which can be peeled.SELECTED DRAWING: Figure 1

Description

The present invention relates to a heat conductive sheet and a method for manufacturing a heat conductive sheet, and a heat radiating component and a method for manufacturing a heat radiating component.

With the further improvement of the performance of electronic devices, the density and mounting of electronic components such as semiconductor elements are increasing. Along with this, in order to more efficiently dissipate the heat generated from the electronic components constituting the electronic device, various heat sources [for example, LSI (Large Scale Integration), CPU (Central Processing Unit), transistor, LED (Light Emitting) Various devices such as a diode) and a heat conductive sheet used by sandwiching the heat sink (for example, a heat radiating fan, a heat radiating plate, etc.) and the like are provided.

As the heat conductive sheet, a sheet formed by slicing a cured product obtained by curing a heat conductive resin composition in which a heat conductive filler such as an inorganic filler is mixed with a polymer matrix after molding into a sheet is widely used. Has been done.

As such a heat conductive sheet, a thin heat conductive sheet having high thermal conductivity is desired in order to reduce the thermal resistance between various heat sources and the radiator. In addition, the heat conductive sheet is required to have tackiness (adhesiveness) from the viewpoint of handleability such as being attached to an adherend and the delivery form in a state of being attached to an adherend (for example, a heat sink). May be done. However, in the method of producing a heat conductive sheet by slicing a cured product of the heat conductive resin composition, the surface of the heat conductive sheet formed by the slicing is not tacky.

Therefore, the heat conductive sheet obtained by constructing the heat conductive resin composition by changing the ratio of the silicone A agent and the B agent is pressed or sandwiched between PET (polyethylene terephthalate) films and left to contribute to the reaction. A technique has been proposed in which components that do not bleed are easily attached to an adherend (see, for example, Patent Documents 1 and 2).

Japanese Patent No. 5766335 Japanese Patent No. 5725299

However, in the heat conductive sheet of the proposed technology, when the ratio of the A agent of silicone is increased, it has high flexibility and easily adheres to the adherend, but when the thickness is thin, the heat conductive sheet is removed from the release film. There was a problem that the handleability suddenly deteriorated, such as the main body being stretched or torn off.
Further, if the adhesive layers are formed on both sides of the heat conductive sheet body, there is a problem that the thermal resistance is lowered.

An object of the present invention is to achieve the following object. That is, the present invention relates to a heat conductive sheet having excellent handleability and excellent thermal resistance without relying on the flexibility of the heat conductive sheet body, a method for manufacturing the same, and a heat radiating component using the heat conductive sheet. And its manufacturing method.

The means for solving the above-mentioned problems are as follows. That is,
<1> A heat conductive sheet body containing a heat conductive filler, which is used between an electronic component and a radiator, and a heat conductive sheet body.
An adhesive layer arranged in contact with the entire surface of the first surface of the heat conductive sheet body,
A release film arranged in contact with the surface of the adhesive layer opposite to the surface of the heat conductive sheet main body, and
A peelable protective film arranged in contact with the entire surface of the second surface opposite to the first surface of the heat conductive sheet body, and
It is a heat conductive sheet characterized by having.
<2> The heat conductive sheet according to <1>, wherein the adhesiveness between the heat conductive sheet main body and the adhesive layer is higher than the adhesiveness between the heat conductive sheet main body and the protective film.
<3> The heat conductive sheet according to any one of <1> to <2>, wherein the adhesiveness between the heat conductive sheet main body and the protective film is higher than the adhesiveness between the adhesive layer and the release film. be.
<4> The heat conductive sheet according to any one of <1> to <3>, wherein the adhesive layer is an acrylic adhesive layer.
<5> The heat conductive sheet body contains a binder resin, and the heat conductive sheet body contains a binder resin.
The heat conductive sheet according to any one of <1> to <4>, wherein the binder resin is a cured product of a silicone resin.
<6> The heat conductive sheet according to any one of <1> to <5>, wherein the heat conductive filler contains at least one of carbon fibers and boron nitride.
<7> A process for manufacturing a heat conductive sheet body containing a heat conductive filler, which is used between an electronic component and a radiator, and a process for manufacturing the heat conductive sheet body.
An adhesive layer forming step of forming the adhesive layer so that the adhesive layer is in contact with the entire surface of the first surface of the heat conductive sheet body.
A release film arranging step of arranging the release film so that the release film is in contact with the surface of the adhesive layer on the side opposite to the surface of the heat conductive sheet main body.
A protective film arranging step of arranging the protective film so that the peelable protective film is in contact with the entire surface of the second surface opposite to the first surface of the heat conductive sheet body.
A method for producing a heat conductive sheet, which comprises.
<8> The method for producing a heat conductive sheet according to <7>, wherein the pressure-sensitive adhesive layer forming step is performed by applying the pressure-sensitive adhesive composition to the entire surface of the first surface of the heat conductive sheet main body. ..
<9> A heat conductive sheet body containing a heat conductive filler, which is used between an electronic component and a radiator, and a heat conductive sheet body.
An adhesive layer arranged in contact with the entire surface of the first surface of the heat conductive sheet body,
A peelable protective film arranged in contact with the entire surface of the second surface opposite to the first surface of the heat conductive sheet body, and
A heat radiating body arranged in contact with the surface of the adhesive layer opposite to the surface of the heat conductive sheet main body, and
It is a heat radiating component characterized by having.
<10> The heat radiating component according to <9>, wherein the heat radiating body is any one of a heat spreader, a heat sink, a vapor chamber, and a heat pipe.
<11> A peeling step of peeling the release film of the heat conductive sheet according to any one of <1> to <6> from the adhesive layer.
A sticking step of attaching the heat conductive sheet from which the release film has been peeled off so that the adhesive layer is in contact with the heat radiating body, and a sticking step of sticking the heat conductive sheet to the heat radiating body.
It is a method for manufacturing a heat radiating component, which comprises.

According to the present invention, a heat conductive sheet having excellent handleability and excellent thermal resistance without depending on the flexibility of the heat conductive sheet body, a method for manufacturing the same, and heat dissipation parts using the heat conductive sheet, and The manufacturing method can be provided.

FIG. 1 is a schematic cross-sectional view of an example of a heat conductive sheet. FIG. 2 is a diagram of an example of heat radiating parts. FIG. 3A is a diagram for explaining an example of a method for manufacturing a heat radiating component (No. 1). FIG. 3B is a diagram for explaining an example of a method for manufacturing a heat radiating component (No. 2). FIG. 3C is a diagram for explaining an example of a method for manufacturing a heat radiating component (No. 3). FIG. 3D is a diagram for explaining an example of a method of manufacturing a heat radiating component (No. 4). FIG. 4 is a schematic cross-sectional view of the heat conductive sheet of Comparative Example 1.

(Heat conduction sheet)
The heat conductive sheet of the present invention has a heat conductive sheet main body, an adhesive layer, a release film, and a protective film, and further has other members, if necessary.
In the heat conductive sheet, the adhesive layer is arranged in contact with the entire surface of the first surface of the heat conductive sheet main body.
In the heat conductive sheet, the release film is arranged in contact with the surface of the adhesive layer opposite to the surface of the heat conductive sheet on the main body side.
In the heat conductive sheet, the second release film is arranged in contact with the surface of the second adhesive layer opposite to the surface of the heat conductive sheet on the main body side.
In the heat conductive sheet, the protective film is arranged in contact with the entire surface of the second surface opposite to the first surface of the heat conductive sheet main body.

In the heat conductive sheet, the heat conductive sheet body may usually be sandwiched between two release films.
In this case, when the heat conductive sheet body has high flexibility, it is difficult to peel off the release film from the heat conductive sheet body, and the handleability is poor.

Therefore, the present inventors have studied to provide an adhesive layer and a release film on both sides of the heat conductive sheet main body. However, in this case, the thermal resistance decreases.

Therefore, as a result of further studies, the present inventors have formed an adhesive layer only on one side of the heat conductive sheet body, and while attaching a release film to the adhesive layer, on the other side of the heat conductive sheet body. We have found that by arranging a protective film, both handleability and thermal resistance can be achieved, and the present invention has been completed.

<Heat conduction sheet body>
The heat conductive sheet body contains a heat conductive filler and, if necessary, other components such as a binder resin.
The heat conductive sheet body is used as an interposition between an electronic component and a heat radiating body.

The planar shape of the heat conductive sheet body is not particularly limited and may be appropriately selected depending on the intended purpose, and may be quadrangular or circular.

The heat conductive sheet body may or may not have adhesiveness.

<< Thermal Conductive Filler >>
The thermally conductive filler is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a carbon material and an inorganic filler other than the carbon material.

<<< Carbon material >>>
The carbon material is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include particulate carbon material and fibrous carbon material (carbon fiber).

-Particulate carbon material-
Examples of the particulate carbon material include artificial graphite, scaly graphite, flaky graphite, natural graphite, acid-treated graphite, expansive graphite, expanded graphite and other graphite; carbon black and the like.
The expanded graphite can be obtained, for example, by chemically treating graphite such as scaly graphite with sulfuric acid or the like, heat-treating the expanded graphite to expand it, and then refining it.
As the expanded graphite, a commercially available product may be used, and examples thereof include EC1500, EC1000, EC500, EC300, EC100, and EC50 (all trade names) manufactured by Ito Graphite Industry Co., Ltd.

The aspect ratio (average major axis / average minor axis) of the particulate carbon material is not particularly limited, but is preferably 1 or more and 10 or less, and more preferably 1 or more and 5 or less. The "aspect ratio of the particulate carbon material" in the present invention is the maximum diameter (major diameter) and the maximum diameter of any 50 particulate carbon materials observed using an SEM (scanning electron microscope). It can be obtained by measuring the particle diameter (minor diameter) in the orthogonal direction and calculating the average value of the ratio of the major axis to the minor axis (major axis / minor axis).

The average particle size of the particulate carbon material is preferably 50 μm or more, more preferably 150 μm or more, preferably 300 μm or less, and more preferably 200 μm or less in terms of volume average particle size. ..
When the average particle size of the particulate carbon material is 50 μm or more, the heat transfer path of the particulate carbon material can be formed better in the heat conductive sheet body, so that the heat conductivity of the heat conductive sheet body can be further enhanced. Can be done. When the average particle size of the particulate carbon material is 300 μm or less, good flexibility of the heat conductive sheet body can be ensured.

− Fibrous carbon material (carbon fiber) −
The fibrous carbon material (carbon fiber) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, pitch-based carbon fiber, PAN-based carbon fiber, carbon fiber obtained by graphitizing PBO fiber, arc. Carbon fibers synthesized by a discharge method, a laser evaporation method, a CVD method (chemical vapor phase growth method), a CCVD method (catalytic chemical vapor phase growth method), or the like can be used. Among these, carbon fibers obtained by graphitizing PBO fibers and pitch-based carbon fibers are particularly preferable from the viewpoint of thermal conductivity.

The carbon fiber may be an insulating coated carbon fiber having a film on at least a part of the surface of the carbon fiber body.

--Insulation coated carbon fiber ---
The insulating coated carbon fiber contains at least a carbon fiber main body and a film on at least a part of the surface of the carbon fiber main body, and further contains other components as necessary.
The film is made of a cured product of a polymerizable material.

If necessary, the carbon fiber body can be used by surface-treating a part or all of the carbon fiber body in order to improve the adhesion to the film.
As the surface treatment, for example, a metal, a metal compound, an organic compound or the like is attached to the surface of a functional group or a carbon fiber body introduced into the surface by oxidation treatment, nitriding treatment, nitration, sulfonation, or these treatments. Alternatively, a process of combining may be mentioned.
Examples of the functional group include a hydroxyl group, a carboxyl group, a carbonyl group, a nitro group, an amino group and the like.

--- Cured product of polymerizable material ---
The cured product of the polymerizable material is obtained by curing the polymerizable material. In other words, the cured product is also a polymer of the polymerizable material.

The polymerizable material is not particularly limited as long as it is a polymerizable organic material, and can be appropriately selected depending on the intended purpose. Examples thereof include a polymerizable organic compound and a polymerizable resin. Be done.
Examples of the polymerization caused by the polymerizable material include radical polymerization, cationic polymerization, and aniopolymerization. Among these, radical polymerization is preferable because there are many types of polymerizable materials, polymerization initiators, and solvents that can be applied, and various cured products can be obtained.
That is, the polymerizable material is preferably a radically polymerizable material.

--- Radical polymerizable material ---
The radically polymerizable material is not particularly limited as long as it is a material that radically polymerizes using energy, and can be appropriately selected depending on the intended purpose. For example, a compound having a radically polymerizable double bond may be used. Can be mentioned.

Examples of the radically polymerizable double bond include a vinyl group, an acryloyl group, and a methacryloyl group.

The number of the radically polymerizable double bonds in the compound having the radically polymerizable double bonds is preferably two or more from the viewpoint of film strength including heat resistance and solvent resistance. That is, the compound having a radically polymerizable double bond preferably contains at least one compound having two or more radically polymerizable double bonds.

Examples of the compound having two or more radically polymerizable double bonds include divinylbenzene and a compound having two or more (meth) acryloyl groups.
Examples of the compound having two or more (meth) acryloyl groups include ethylene glycol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and (poly) propylene glycol di. (Meta) Acrylate, Pentaerythritol Tetra (Meta) Acrylate, Pentaerythritol Tri (Meta) Acrylate, Pentaerythritol Di (Meta) Acrylate, Trimethylol Propantri (Meta) Acrylate, Dipentaerythritol Hexa (Meta) Acrylate, Dipentaerythritol Penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, tetramethylol methanetri (meth) acrylate, Examples thereof include tetramethylol propanetetra (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, and (poly) ethoxylated bisphenol A di (meth) acrylate.
The (meth) acryloyl group in the present specification is a general term for an acryloyl group and a methacryloyl group, and the (meth) acrylate is a general term for an acrylate and a methacrylate.

The radically polymerizable material may be used alone or in combination of two or more.

The molecular weight of the radically polymerizable material is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 50 or more and 500 or less.

The content of the structural unit derived from the polymerizable material in the cured product and the film is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 50% by mass or more, preferably 90% by mass or more. Is more preferable.

The average thickness of the film in the insulating coated carbon fiber is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of achieving high insulating properties, 50 nm or more is preferable, and 100 nm or more is more preferable. , 200 nm or more is particularly preferable. The upper limit of the average thickness is not particularly limited and may be appropriately selected depending on the intended purpose. For example, 1,000 nm or less is preferable, and 500 nm or less is more preferable.
The average thickness can be determined, for example, by observation with a transmission electron microscope (TEM).

In the heat conductive sheet main body, the insulating coated carbon fiber may not have the film at the end portion in the longitudinal direction thereof. In particular, since the heat conductive sheet body may be produced by slicing a block-shaped molded body, on the surface of the heat conductive sheet body, the insulating coated carbon fibers are end portions in the longitudinal direction thereof. In, the film does not have to be present.

The method for producing the insulating coated carbon fiber is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include an insulating coated carbon fiber manufacturing process described later.

The average fiber length (average major axis length) of the carbon fibers is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 50 μm or more and 250 μm or less, more preferably 75 μm or more and 200 μm or less, and 90 μm. More than 170 μm is particularly preferable.

The average fiber diameter (average minor axis length) of the carbon fibers is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 4 μm or more and 20 μm or less, and more preferably 5 μm or more and 14 μm or less.

The aspect ratio (average major axis length / average minor axis length) of the carbon fibers is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 8 or more, and 9 or more and 30 or less. preferable. If the aspect ratio is less than 8, the fiber length (major axis length) of the carbon fibers is short, so that the thermal conductivity may decrease.
Here, the average major axis length and the average minor axis length of the carbon fibers can be measured by, for example, a microscope, a scanning electron microscope (SEM), or the like.

The content of the carbon fibers in the heat conductive sheet body is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by volume or more and 40% by volume or less, and 12% by volume or more and 38% by volume. The following is more preferable, and 15% by volume or more and 30% by volume or less is particularly preferable.

<<< Inorganic filler >>>
The material of the inorganic filler is not particularly limited and may be appropriately selected depending on the intended purpose. For example, aluminum nitride (aluminum nitride: AlN), silica, aluminum oxide (alumina), boron nitride, titania, glass, etc. Examples thereof include zinc oxide, silicon carbide, silicon (silicone), silicon oxide, aluminum oxide, and metal particles. Among these, aluminum oxide, boron nitride, aluminum nitride, zinc oxide and silica are preferable, and aluminum oxide, aluminum nitride and zinc oxide are particularly preferable from the viewpoint of thermal conductivity.
In the present invention, two or more kinds of inorganic fillers may be combined to form the inorganic filler.
When only the inorganic filler is used as the heat conductive filler in the heat conductive sheet main body, it is preferable to use a combination of two or more kinds of inorganic fillers as the inorganic filler, and at least boron nitride is contained. Is more preferable.

The shape of the inorganic filler is not particularly limited and may be appropriately selected depending on the intended purpose. For example, spherical, elliptical spherical, massive, granular, flat, needle-like, scaly, and aggregated (aggregated). And so on.
In the present invention, a plurality of inorganic fillers having different shapes may be combined to form the inorganic filler.
When boron nitride is contained as the inorganic filler, the shape of the boron nitride is preferably needle-like or scaly, and particularly preferably scaly, from the viewpoint of orientation.
When the inorganic filler other than the boron nitride is contained as the inorganic filler, the shape of the inorganic filler other than the boron nitride is preferably spherical or elliptical from the viewpoint of filling property, and the spherical shape is particularly preferable.
In the present specification, the inorganic filler is different from the carbon material.
When only the inorganic filler is used as the heat conductive filler in the heat conductive sheet main body, it is preferable to use a combination of a plurality of inorganic fillers having different shapes as the inorganic filler.

The inorganic filler may be surface-treated. For example, when the inorganic filler is treated with a coupling agent as the surface treatment, the dispersibility of the inorganic filler is improved and the flexibility of the heat conductive sheet is improved.
The coupling agent is not particularly limited and may be selected depending on the intended purpose. Examples thereof include a silane coupling agent, a titanate-based coupling agent, and an aluminate-based coupling agent.

When a scaly inorganic filler is used as the heat conductive filler in the heat conductive sheet body, the aspect ratio (average major axis / average minor axis) of the scaly inorganic filler is not particularly limited and is not particularly limited. It can be appropriately selected depending on the situation, and can be, for example, 10 or more and 100 or less.
The average major axis and the average minor axis of the scaly inorganic filler can be measured by, for example, a microscope, a scanning electron microscope (SEM), a particle size distribution meter, or the like.
As a method for measuring the average major axis and the average minor axis, for example, when scaly boron nitride having a hexagonal crystal shape is used as the scaly inorganic filler, 200 or more from the images taken by SEM. Boron nitride may be arbitrarily selected, and the ratio (a / b) of each major axis a to minor axis b may be obtained to calculate the average value.

The average particle size of the inorganic filler is not particularly limited and may be appropriately selected depending on the intended purpose.
When alumina is contained as the inorganic filler, the average particle size of the alumina is preferably 1 μm or more and 10 μm or less, more preferably 1 μm or more and 5 μm or less, and particularly preferably 3 μm or more and 5 μm or less.
When aluminum nitride is contained as the inorganic filler, the average particle size of the aluminum nitride is preferably 0.3 μm or more and 6.0 μm or less, more preferably 0.3 μm or more and 2.0 μm or less, and 0.5 μm or more and 1.5 μm. The following are particularly preferred.
When only the inorganic filler is used as the heat conductive filler in the heat conductive sheet main body, it is preferable to use a combination of two or more kinds of inorganic fillers as the inorganic filler, and at least boron nitride is contained. Is more preferable. In that case, the average particle size of the boron nitride is preferably 10 μm or more and 150 μm or less, and more preferably 20 μm or more and 100 μm or less.
The average particle size of the inorganic filler can be measured by, for example, a particle size distribution meter or a scanning electron microscope (SEM).

The content of the inorganic filler in the heat conductive sheet main body is not particularly limited and may be appropriately selected depending on the intended purpose.
When the carbon material and the inorganic filler are used in combination as the heat conductive filler in the heat conductive sheet main body, the content of the inorganic filler is preferably 25% by volume or more and 65% by volume or less, preferably 30% by volume or more. 60% by volume or less is more preferable, and 35% by volume or more and 55% by volume or less is particularly preferable.
When only the inorganic filler is used as the heat conductive filler in the heat conductive sheet main body, the content of the inorganic filler is preferably 30% by volume or more and 90% by volume or less, and 40% by volume or more and 80% by volume or less. More preferably, 45% by volume or more and 75% by volume or less is particularly preferable.

The content of the heat conductive filler in the heat conductive sheet main body is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 30% by volume or more and 90% by volume or less, and 40% by volume or more and 80% by volume. More preferably, it is 45% by volume or more, and particularly preferably 75% by volume or less.

<< Binder resin >>
The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include thermosetting polymers.

Examples of the thermosetting polymer include crosslinked rubber, epoxy resin, polyimide resin, bismaleimide resin, benzocyclobutene resin, phenol resin, unsaturated polyester, diallyl phthalate resin, silicone resin, polyurethane, polyimide silicone, and thermosetting type. Examples thereof include polyimideene ether and thermosetting modified polyphenylene ether. These may be used alone or in combination of two or more.

Examples of the crosslinked rubber include natural rubber, butadiene rubber, isoprene rubber, nitrile rubber, hydrogenated nitrile rubber, chloroprene rubber, ethylene propylene rubber, chlorinated polyethylene, chlorosulfonated polyethylene, butyl rubber, halogenated butyl rubber, and fluororubber. Examples thereof include urethane rubber, acrylic rubber, polyisobutylene rubber, and silicone rubber. Among these, the thermosetting polymer is particularly preferably a silicone resin from the viewpoints of excellent moldability and weather resistance, as well as adhesion and followability to electronic components.

These may be used alone or in combination of two or more.

The silicone resin is not particularly limited and may be appropriately selected depending on the intended purpose, but preferably contains a main agent of a liquid silicone gel and a curing agent. Examples of such a silicone resin include an addition reaction type silicone resin, a heat vulcanization type mirable type silicone resin using a peroxide for vulcanization, and the like. Among these, the addition reaction type silicone resin is particularly preferable because the adhesion to the heat generating surface of the electronic component is required.

As the addition reaction type silicone resin, a two-component addition reaction type silicone resin containing a polyorganosiloxane having a vinyl group as a main agent and a polyorganosiloxane having a Si—H group as a curing agent is preferable.

In the combination of the main agent of the liquid silicone gel and the curing agent, the blending ratio of the main agent and the curing agent is not particularly limited and may be appropriately selected depending on the intended purpose.

The content of the binder resin in the heat conductive sheet body is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by volume or more and 50% by volume or less, and 15% by volume or more and 40% by volume or less. The following is more preferable, and 30% by volume or more and 40% by volume or less is particularly preferable.

<< Other ingredients >>
The other components contained in the heat conductive sheet body are not particularly limited and may be appropriately selected depending on the intended purpose. For example, a thixotropy-imparting agent, a dispersant, a curing accelerator, a retarding agent, and a slight amount can be selected. Examples thereof include tackifiers, plasticizers, flame retardants, antioxidants, stabilizers, and colorants.

The average thickness of the heat conductive sheet body is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.05 mm or more and 5.00 mm or less, and more preferably 0.07 mm or more and 4.00 mm or less. , 0.10 mm or more and 3.00 mm or less is particularly preferable.

The surface of the heat conductive sheet is preferably covered with an exuding component exuded from the heat conductive sheet so as to follow the convex shape of the protruding carbon fibers.
The method of making the surface of the heat conductive sheet in this way can be performed, for example, by a press treatment described later.

<Adhesive layer>
In the heat conductive sheet, the adhesive layer is arranged in contact with the entire surface of the first surface of the heat conductive sheet main body.
The adhesive layer is a layer composed of an adhesive.

The material of the adhesive layer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include acrylic type, rubber type, polyester type and silicone type. The adhesive layer is acrylic type. It is preferably an adhesive layer.
The acrylic pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer containing an acrylic polymer.

The average thickness of the adhesive layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.5 μm or more and 30 μm or less, and more preferably 1 μm or more and 20 μm or less.

<Release film>
In the heat conductive sheet, the release film is arranged in contact with the surface of the adhesive layer opposite to the surface of the heat conductive sheet on the main body side.
The release film is a film that can be peeled off from the adhesive layer.
In the heat conductive sheet, when the release film is to be peeled from the adhesive layer, the adhesive layer is not peeled from the heat conductive sheet main body, and the adhesive layer remains on the heat conductive sheet main body side. ..

The release film is preferably in contact with the entire surface of the adhesive layer. In this case, the area of the release film is larger than the area of the adhesive layer, and a part of the surface of the release film on the side in contact with the adhesive layer is exposed around the adhesive layer and the heat conductive sheet main body. May be.

Examples of the layer structure of the release film include a releaseable laminated film having a release film base material and a release layer provided on one side of the release film base material.
The base material for the release film in the releaseable laminated film is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include papers and polymer films.
Examples of the polymer film include polyolefin films such as polyethylene films and polypropylene films, and low-polarity substrates such as polyethylene terephthalate films. Among these, polyethylene terephthalate film is preferable.
As the release agent constituting the release layer, for example, a general-purpose addition-type or condensation-type silicone-based release agent or a long-chain alkyl group-containing compound is used. In particular, an addition type silicone release agent having high reactivity is preferably used.
As the silicone-based release agent, a commercially available product may be used, for example, BY24-4527, SD-7220, etc. manufactured by Toray Dow Corning Silicone Co., Ltd., KS-3600, KS-, manufactured by Shin-Etsu Chemical Co., Ltd. 774, X62-2600 and the like can be mentioned. Further, it contains a silicone resin which is an organic silicon compound having an SiO ₂ units and _{(CH 3) 3 SiO 1/2} units or _{CH 2 = CH (CH 3)} SiO 1/2 units in the silicone-based release agent preferable.
As the silicone resin, a commercially available product may be used, for example, BY24-843, SD-7292, SHR-1404 manufactured by Toray Dow Corning Silicone Co., Ltd., KS-3800 manufactured by Shin-Etsu Chemical Co., Ltd., etc. Examples thereof include X92-183.

The average thickness of the release film is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1 μm or more and 300 μm or less. Further, from the viewpoint of operability of the release film, 5 μm or more is preferable. Further, from the viewpoint of retaining the heat conductive sheet, it is preferably 25 μm or more and 150 μm or less.
The average thickness of the release film can be appropriately selected in consideration of the balance between the release film and the protective film, for example.

<Protective film>
In the heat conductive sheet of the present invention, the protective film is arranged in contact with the entire surface of the second surface opposite to the first surface of the heat conductive sheet main body.
The protective film can be peeled off from the heat conductive sheet.
The protective film may or may not have adhesiveness.
For example, when the heat conductive sheet body has adhesiveness, the protective film does not have to have adhesiveness. On the other hand, when the heat conductive sheet body does not have adhesiveness, the protective film has adhesiveness.

The protective film is preferably in contact with the entire surface of the heat conductive sheet body. In this case, the area of the protective film is larger than the area of the heat conductive sheet body, and a part of the surface of the protective film on the side in contact with the heat conductive sheet body is exposed around the heat conductive sheet body. You may be.

When the heat conductive sheet main body has adhesiveness, examples of the material and structure of the protective film include the materials and structures described in the release film.

When the heat conductive sheet body does not have adhesiveness, the protective film is a film having adhesiveness on one side.
The adhesive film has, for example, a base material and an adhesive layer.
The base material is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a polyethylene terephthalate film is preferable.
The material of the adhesive layer is not particularly limited and may be appropriately selected depending on the intended purpose.

In the heat conductive sheet of the present invention, it is preferable that the adhesiveness between the heat conductive sheet main body and the adhesive layer is higher than the adhesiveness between the heat conductive sheet main body and the protective film. By doing so, when the protective film is peeled off from the heat conductive sheet main body, it is possible to prevent the heat conductive sheet main body and the adhesive layer from being peeled off.

In the heat conductive sheet of the present invention, it is preferable that the adhesiveness between the heat conductive sheet main body and the protective film is higher than the adhesiveness between the adhesive layer and the release film. By doing so, when the release film is peeled from the adhesive layer, the release film can be selectively peeled off without the protective film being peeled off.

The average thickness of the protective film is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1 μm or more and 300 μm or less. Further, from the viewpoint of operability of the protective film, 5 μm or more is preferable. Further, from the viewpoint of retaining the heat conductive sheet, it is preferably 25 μm or more and 150 μm or less.
The average thickness of the protective film can be appropriately selected in consideration of the balance between the release film and the protective film, for example.

<Electronic components>
The electronic component is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a CPU (Central Processing Unit), an MPU (Micro Processing Unit), and a GPU (Graphics Processing Unit).

<Heat radiator>
The radiator is not particularly limited as long as it is a member that dissipates heat generated by electronic components, and can be appropriately selected depending on the intended purpose. For example, a heat spreader, a heat sink, a heat sink, a vapor chamber, a heat pipe, or the like can be used. Can be mentioned.
The heat spreader is a member for efficiently transferring the heat of the electronic component to other components. The material of the heat spreader is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include copper and aluminum. The heat spreader is not particularly limited and may be appropriately selected depending on the intended purpose, and is usually in the shape of a flat plate.
The heat sink is a member for releasing the heat of the electronic component into the air. The material of the heat sink is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include copper and aluminum. The heat sink has, for example, a plurality of fins. The heat sink has, for example, a base portion and a plurality of fins provided so as to extend in a direction non-parallel (for example, in a direction orthogonal to the base portion) with respect to one surface of the base portion.
The heat spreader and the heat sink generally have a solid structure having no space inside.
The vapor chamber is a hollow structure. A volatile liquid is sealed in the internal space of the hollow structure. Examples of the vapor chamber include a heat spreader having a hollow structure, a plate-shaped hollow structure having a heat sink having a hollow structure, and the like.
The pete pipe is a hollow structure having a cylindrical shape, a substantially cylindrical shape, or a flat tubular shape. A volatile liquid is sealed in the internal space of the hollow structure.

Here, an example of the heat conductive sheet of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of an example of a heat conductive sheet.
The heat conductive sheet 100 of FIG. 1 has a heat conductive sheet main body 1, an adhesive layer 2, a release film 3, and a protective film 4.
The adhesive layer 2 is arranged in contact with the entire surface of the first surface 1a of the heat conductive sheet main body 1.
The release film 3 is arranged in contact with the entire surface of the adhesive layer 2 on the side opposite to the surface on the heat conductive sheet body 1 side.
The protective film 4 is arranged in contact with the entire surface of the second surface 1b on the opposite side of the first surface of the heat conductive sheet main body 1.

(Manufacturing method of heat conductive sheet)
The method for producing a heat conductive sheet of the present invention includes a heat conductive sheet main body manufacturing step, an adhesive layer forming step, a release film placement step, and a protective film placement step, and further includes other steps, if necessary. ..
The order of each step is not limited to the above-described order as long as it does not interfere with manufacturing.

The method for producing a heat conductive sheet of the present invention is an example of the method for producing the heat conductive sheet of the present invention.

<Heat conduction sheet body manufacturing process>
The heat conductive sheet main body manufacturing step is an example of a step of manufacturing the heat conductive sheet main body in the heat conductive sheet of the present invention.
The heat conductive sheet main body manufacturing step includes, for example, at least a molded body manufacturing process and a molded body sheet manufacturing process, preferably including an insulating coated carbon fiber manufacturing process and a surface coating process, and further includes, if necessary. Including other processing. In the following description, when a needle-shaped or scaly inorganic filler is used instead of the carbon fiber, the carbon fiber can be appropriately read as the inorganic filler. Further, if the inorganic filler is insulating, it is not necessary to form an insulating coating.

<< Molded body manufacturing process >>
In the molded body manufacturing process, a heat conductive resin composition containing a binder resin and a heat conductive filler is molded into a predetermined shape and cured to obtain a molded body of the heat conductive resin composition. If it is a process, there is no particular limitation, and it can be appropriately selected according to the purpose.

The heat conductive resin composition contains at least a binder resin and a heat conductive filler, and further contains other components, if necessary.
Examples of the binder resin include the binder resin exemplified in the description of the heat conductive sheet main body in the heat conductive sheet.
Examples of the heat conductive filler include the heat conductive filler exemplified in the description of the heat conductive sheet main body in the heat conductive sheet.

In the molded body manufacturing process, the method of molding the thermally conductive resin composition into a predetermined shape is not particularly limited and may be appropriately selected depending on the intended purpose. For example, an extrusion molding method or mold molding. The law etc. can be mentioned.

When the heat conductive sheet main body contains carbon fibers, the molded body manufacturing process involves filling the hollow mold with the heat conductive resin composition and heat-curing the heat conductive resin composition. Is preferable in that the carbon fibers can be randomly oriented in the obtained heat conductive sheet body.
In the obtained heat conductive sheet main body, since the carbon fibers are randomly oriented, the entanglement between the carbon fibers is increased, so that the heat is higher than that in the case where the carbon fibers are oriented in a certain direction. The thermal conductivity of the conductive sheet body increases. Further, when the heat conductive sheet main body further contains the inorganic filler, the carbon fibers are randomly oriented, so that the carbon fibers and the inorganic filler are mixed in addition to the entanglement of the carbon fibers. Since the number of contacts is increased, the thermal conductivity of the heat conductive sheet body is further increased as compared with the case where the carbon fibers are oriented in a certain direction.

The extrusion molding method and the mold molding method are not particularly limited, and the viscosity of the heat conductive resin composition and the obtained heat conduction can be obtained from various known extrusion molding methods and mold molding methods. It can be appropriately adopted according to the characteristics required for the seat body and the like.

When the heat conductive resin composition is extruded from a die in the extrusion molding method, or when the heat conductive resin composition is press-fitted into a mold in the mold molding method, for example, the binder resin flows. , Some of the carbon fibers are oriented along the flow direction, but most of them are oriented randomly.

When a slit is attached to the tip of the die, the carbon fibers tend to be easily oriented in the central portion with respect to the width direction of the extruded molded body block. On the other hand, carbon fibers tend to be randomly oriented in the peripheral portion in the width direction of the molded body block due to the influence of the slit wall.

The size and shape of the molded body (block-shaped molded body) can be determined according to the required size of the heat conductive sheet body. For example, a rectangular parallelepiped having a vertical cross section of 0.5 cm or more and 15 cm or less and a horizontal size of 0.5 cm or more and 15 cm or less can be mentioned. The length of the rectangular parallelepiped may be determined as needed.

The curing of the heat conductive resin composition in the molded body manufacturing process is preferably thermosetting.
The curing temperature in the thermosetting is not particularly limited and may be appropriately selected depending on the intended purpose. For example, when the binder resin contains the main agent of the liquid silicone gel and the curing agent, it is 60 ° C. or higher. It is preferably 120 ° C. or lower.
The curing time in the heat curing is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include 0.5 hour and more and 10 hours or less.

<< Molded sheet manufacturing process >>
The molded body sheet manufacturing process is not particularly limited as long as it is a process of cutting the molded body into a sheet to obtain a molded body sheet, and can be appropriately selected depending on the intended purpose, for example, by a slicing device. It can be carried out.

In the molded body sheet manufacturing process, the molded body is cut into a sheet to obtain a molded body sheet. On the surface of the obtained molded body sheet, for example, the carbon fibers are projected. This is because when the molded body is cut into a sheet by a slicing device or the like, the hardening component of the binder resin becomes a cutting member of the slicing device or the like due to the difference in hardness between the curing component of the binder resin and the carbon fiber. It is considered that this is because the cured component of the binder resin is removed from the surface of the carbon fiber on the surface of the molded body sheet by being pulled and stretched.

The slicing device is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include an ultrasonic cutter and a plane (plane). When the molding method is an extrusion molding method, the cutting direction of the molded body is preferably 60 degrees or more and 120 degrees or less, preferably 70 degrees or more, with respect to the extrusion direction because some of them are oriented in the extrusion direction. 100 degrees or less is more preferable, and 90 degrees (vertical) is particularly preferable.

The average thickness of the molded body sheet is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.06 mm or more and 5.01 mm or less, and more preferably 0.08 mm or more and 4.01 mm or less. It is particularly preferably 0.11 mm or more and 3.01 mm or less.

<< Surface coating treatment >>
The surface coating treatment is not particularly limited as long as it is a treatment in which the surface of the molded body sheet is covered with an exuding component exuded from the molded body sheet so as to follow the convex shape of the protruding carbon fibers. , And can be appropriately selected according to the purpose, and examples thereof include a press treatment and a molded body sheet leaving treatment.
Here, the "exudative component" is a component contained in the heat conductive resin composition but not contributing to curing, such as a non-curable component and a non-curable component of the binder resin. Means.

<<< Press processing >>
The press treatment is a treatment in which the molded body sheet is pressed and the surface of the molded body sheet is covered with an exuding component exuded from the molded body sheet so as to follow the convex shape of the protruding carbon fibers. If so, there is no particular limitation, and it can be appropriately selected according to the purpose.

The press can be performed using, for example, a pair of press devices including a flat plate and a press head having a flat surface. Alternatively, a pinch roll may be used.

The pressure at the time of pressing is not particularly limited and can be appropriately selected depending on the purpose. However, if it is too low, the thermal resistance tends to be the same as that without pressing, and if it is too high, the sheet stretches. Since there is a tendency, it is preferably 0.1 MPa or more and 100 MPa or less, and more preferably 0.5 MPa or more and 95 MPa or less.

The pressing time is not particularly limited, and can be appropriately selected depending on the binder resin component, the pressing pressure, the sheet area, the exuding amount of the exuding component, and the like.

In the press treatment, in order to exude the exuding component and further promote the effect of coating the surface of the molded body sheet, a press head having a built-in heater may be used while heating. In order to enhance such an effect, the heating temperature is preferably equal to or higher than the glass transition temperature of the binder resin. As a result, the pressing time can be shortened.

In the press treatment, by pressing the molded body sheet, the exuding component is exuded from the molded body sheet, and the surface is covered with the exuding component. Therefore, the obtained heat conductive sheet body can improve the followability and adhesion to the surface of the electronic component, and can reduce the thermal resistance. Further, when the coating with the exudative component has a thickness sufficient to reflect the shape of the carbon fibers on the surface of the heat conductive sheet body, an increase in thermal resistance can be avoided.

The molded body sheet is compressed in the thickness direction by being pressed, and the frequency of contact between the heat conductive fillers can be increased. This makes it possible to reduce the thermal resistance of the heat conductive sheet body.

The press treatment is preferably performed using a spacer for compressing the molded body sheet to a predetermined thickness. That is, the heat conductive sheet body can be formed to a predetermined sheet thickness according to the height of the spacer, for example, by arranging a spacer on the mounting surface facing the press head and pressing the molded body sheet. can.

<<< Molded sheet leaving process >>>
The treatment for leaving the molded body sheet is not particularly limited as long as the molded body sheet is left to stand and the surface of the molded body sheet is covered with the exuding component exuded from the molded body sheet. It can be appropriately selected accordingly.

The treatment of coating the surface of the molded body sheet and the carbon fibers exposed from the surface of the molded body sheet with the exuding component of the binder resin exuded from the molded body sheet is a treatment of leaving the molded body sheet instead of the press treatment. You may. In this case as well, as in the press process, the obtained heat conductive sheet body can improve the followability and adhesion to the surface of the electronic component, and can reduce the thermal resistance. Further, when the coating with the exudative component has a thickness sufficient to reflect the shape of the carbon fibers on the surface of the heat conductive sheet body, an increase in thermal resistance can be avoided.

The leaving time is not particularly limited and may be appropriately selected depending on the intended purpose.

<< Insulation coated carbon fiber fabrication process >>
In the insulating coated carbon fiber production treatment, for example, carbon is activated by applying energy to a mixture of the polymerizable material, the carbon fiber body, the polymerization initiator, and a solvent to activate the polymerization initiator. This is a process of forming a film made of a cured product of a polymerizable material on at least a part of the surface of the fiber body to obtain the insulating coated carbon fiber.

When applying energy to the mixture, it is preferable that the mixture is agitated.

By applying the energy to the mixture to activate the polymerization initiator, an insulating film having a desired thickness is formed on the carbon fiber main body without causing agglomeration of the carbon fiber main bodies. Can be done. Then, the obtained insulating coated carbon fiber can form a film having excellent insulating property as compared with the conventional film, and as a result, the insulating property is greatly improved while maintaining high thermal conductivity.

<<< Polymerization Initiator >>>
The polymerization initiator is not particularly limited as long as it can generate an active species by applying the energy and polymerize the polymerizable material, and can be appropriately selected depending on the intended purpose.
When the polymerizable material is a radically polymerizable material, the polymerization initiator may be, for example, a thermal polymerization initiator such as an azo compound or an organic peroxide, or an ultraviolet polymerization initiator such as an alkylphenone type or an acylphosphine oxide type. Agents and the like can be mentioned.
Examples of the energy include thermal energy and light energy.

That is, when using thermal energy as the energy, for example, by heating the mixture to a temperature equal to or higher than the thermal decomposition temperature of the thermal polymerization initiator, the thermal polymerization initiator is activated and the polymerizable material is polymerized. I do. The thermal energy is applied to the mixture, for example, by heat transfer by heat conduction.
When light energy is used as the energy, for example, the mixture is irradiated with ultraviolet rays to activate the ultraviolet polymerization initiator and polymerize the polymerizable material.

<<< Solvent >>>
Examples of the solvent include organic solvents and water.
Examples of the organic solvent include hexane, cyclohexane, diethyl ether, polyether (glyme), γ-butyrolactone, N-methylpyrrolidone, acetonitrile, tetrahydrofuran, ethyl acetate, xylene, toluene, benzene, dimethyl sulfoxide, acetone, methyl ethyl ketone, and the like. Examples thereof include isopropyl alcohol, ethanol and methanol.
Among these, when divinylbenzene is used as the radically polymerizable material, it is preferable to use ethanol or a mixture of ethanol and isopropyl alcohol, and the radically polymerizable material contains two (meth) acryloyl groups. When the compound having the above is used, it is preferable to use ethanol or a mixture of ethanol and toluene.

<<< Degassing >>>
When producing the insulating coated carbon fiber, the mixture may be degassed. This is to promote the surface wettability of the carbon fiber body. The degassing method is not particularly limited, and examples thereof include a method using decompression and ultrasonic waves.

<<< Inertization >>>
When producing the insulating coated carbon fiber, it may be inert.
The inertation means a treatment for lowering the oxygen concentration.
This is to prevent the polymerization reaction described later from being inhibited by oxygen. The method of inertification is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a method of supplying an inert gas such as nitrogen by bubbling while stirring the mixture, and depressurizing the inside of the container. Examples thereof include a method of replacing nitrogen by nitrogen purging.

<<< Polymerization reaction >>>
When producing the insulating coated carbon fiber, for example, energy is applied while stirring the mixture to form a film made of a cured product of the polymerizable material on at least a part of the carbon fiber main body.

When the energy is thermal energy, the temperature of the mixture at the time of polymerization is preferably 0 ° C. or higher and 200 ° C. or lower, more preferably 25 ° C. or higher and 150 ° C. or lower, and 50 ° C. or higher and 100 ° C. or lower. Is particularly preferable. This is because when the temperature of the mixture at the time of polymerization is 0 ° C. or higher and 200 ° C. or lower, the film can be reliably formed and the insulating coated carbon fiber having high insulating properties can be obtained.

In the insulating coated carbon fiber producing treatment, it is preferable to lower the temperature (cool) to room temperature after the polymerization reaction. This is because the temperature of the solvent is lowered to precipitate a polymer dissolved in a small amount in the solvent as the film. The method of cooling is not particularly limited, and examples thereof include a method of immersing the reaction vessel in a cooling tank while controlling the temperature.

In the insulating coated carbon fiber manufacturing process, for example, the following process is performed. Before the polymerization reaction, the carbon fiber body and the polymerizable material (monomer) exist in a solvent in a dispersed / dissolved state under stirring. After applying energy, the monomer is polymerized in the solution, polymerized to the precipitation critical chain length in the solvent, and then the polymer is precipitated on the surface of the carbon fiber body as a trigger (nucleus) for precipitation. At that time, the polymer formed is insoluble in the solvent, or even if it is dissolved, it is very small when taken as a whole. When a polymerizable group remains in the precipitated polymer, a reaction of the monomer is expected, further precipitation occurs, and physical and chemical lamination is expected. After that, by cooling, the temperature of the reaction vessel is lowered and the solubility in the solvent is lowered. As a result, even a small amount of the polymer dissolved in the solvent is expected to contribute to the polymer film thickness, and the contribution is moderate. By doing so, the concern about unity can be reduced. Then, in the insulation-coated carbon fiber manufacturing process, it is possible to form a uniform film having high selectivity on the surface of the carbon fiber main body, as compared with emulsion polymerization in which the carbon fibers are embedded by random phase separation. The formed insulating film has a higher insulating property than the conventional insulating coating.
The above-mentioned polymerization reaction is a reaction for precipitating an insulating film made of a polymer (cured product) on the carbon fiber main body, and is a reaction similar to precipitation polymerization. However, it differs from ordinary precipitation polymerization in that it is not a mechanism mainly due to electrostatic attraction / adsorption, absorption of monomers and initiator components, and bonding by surface functional groups.

Further, in the insulating coated carbon fiber manufacturing process, the obtained insulating coated carbon fiber can be precipitated after the cooling.
By precipitating the obtained insulating coated carbon fibers, it becomes easy to separate them from the solvent. The sedimentation can be performed by allowing the reaction vessel to stand for a certain period of time after cooling.

<Adhesive layer forming process>
The adhesive layer forming step is not particularly limited as long as it is a step of forming the adhesive layer so that the adhesive layer is in contact with the entire surface of the first surface of the heat conductive sheet main body, and is appropriately selected depending on the intended purpose. This can be done, for example, a method of applying the pressure-sensitive adhesive composition to the entire surface of the first surface of the heat conductive sheet body.
The pressure-sensitive adhesive layer is the pressure-sensitive adhesive layer in the heat-conducting sheet of the present invention, and the pressure-sensitive adhesive layer forming step is an example of a step of forming the pressure-sensitive adhesive layer in the heat-conducting sheet of the present invention.
The pressure-sensitive adhesive composition is not particularly limited as long as it can form a pressure-sensitive adhesive layer, and can be appropriately selected depending on the intended purpose. Examples thereof include an acrylic pressure-sensitive adhesive composition.
The pressure-sensitive adhesive composition contains, for example, a pressure-sensitive adhesive component and a solvent, and further contains other components as needed.

<Release film placement process>
The release film arranging step is not particularly limited as long as it is a step of arranging the release film so that the release film is in contact with the surface of the pressure-sensitive adhesive layer on the side opposite to the surface of the heat conductive sheet main body side. It can be appropriately selected accordingly.
The release film is the release film in the heat conductive sheet of the present invention.

<Protective film placement process>
The protective film arranging step is particularly limited to a step of arranging the protective film so that the peelable protective film comes into contact with the entire surface of the second surface opposite to the first surface of the heat conductive sheet body. There is no limitation, and it can be appropriately selected according to the purpose.
The protective film is the protective film in the heat conductive sheet of the present invention.

(Heat dissipation parts)
The heat radiating component of the present invention has a heat conductive sheet main body, an adhesive layer, a protective film, and a heat radiating body, and further has other members, if necessary.
In the heat radiating component, the adhesive layer is arranged in contact with the entire surface of the first surface of the heat conductive sheet main body.
In the heat radiating component, the protective film is arranged in contact with the entire surface of the second surface opposite to the first surface of the heat conductive sheet main body.
In the heat radiating component, the heat radiating body is arranged in contact with the surface of the adhesive layer on the side opposite to the surface of the heat conductive sheet main body.

Examples of the heat conductive sheet main body include the heat conductive sheet main body in the heat conductive sheet of the present invention.
Examples of the adhesive layer include the adhesive layer in the heat conductive sheet of the present invention.
Examples of the release film include the release film in the heat conductive sheet of the present invention.
Examples of the protective film include the protective film in the heat conductive sheet of the present invention.
Examples of the heat radiating body include the heat radiating body mentioned in the description of the heat conductive sheet of the present invention.

The heat-dissipating component can be manufactured, for example, by the method for manufacturing a heat-dissipating component described later.

Here, an example of the heat radiating component of the present invention will be described with reference to the drawings.
FIG. 2 is a schematic cross-sectional view of an example of a heat radiating component.
The heat radiating component 200 of FIG. 2 has a heat conductive sheet main body 1, an adhesive layer 2, a protective film 4, and a heat radiating body 5.
The adhesive layer 2 is arranged in contact with the entire surface of the first surface of the heat conductive sheet main body 1.
The protective film 4 is arranged in contact with the entire surface of the second surface opposite to the first surface of the heat conductive sheet main body 1.
The heat radiating body 5 is arranged in contact with the surface of the adhesive layer 2 on the side opposite to the surface on the heat conductive sheet main body 1 side. The heat radiating body 5 is a vapor chamber having a hollow structure. A volatile liquid is sealed in the internal space of the hollow structure. The heat radiating body 5 is not in direct contact with the heat conductive sheet main body 1.

(Manufacturing method of heat dissipation parts)
The method for manufacturing a heat-dissipating component of the present invention includes a peeling step and a sticking step, and further includes other steps, if necessary.
The method for manufacturing the heat-dissipating component is an example of the method for manufacturing the heat-dissipating component of the present invention.

<Peeling process>
The peeling step is not particularly limited as long as it is a step of peeling the peeling film of the heat conductive sheet of the present invention from the adhesive layer, and can be appropriately selected depending on the intended purpose.

In the heat conductive sheet of the present invention, it is preferable that the adhesiveness between the heat conductive sheet main body and the protective film is higher than the adhesiveness between the adhesive layer and the release film. By doing so, when the release film is peeled off from the heat conductive sheet, the release film can be selectively peeled off without peeling off the protective film.
For example, when the release film or the protective film is peeled from the heat conductive sheet, which of the release film and the protective film is peeled off differs each time the release film is peeled off. It may not be possible to paste.
On the other hand, in the method for manufacturing a heat-dissipating component of the present invention, when the adhesiveness between the heat conductive sheet body and the protective film is higher than the adhesiveness between the adhesive layer and the release film, the heat conduction When the release film is peeled off from the sheet, the release film can be selectively peeled off without peeling off the protective film. Therefore, in the sticking step, the adhesive layer can be reliably stuck to the heat radiating body.

<Attachment process>
The sticking step is not particularly limited as long as it is a step of sticking the heat conductive sheet from which the release film is peeled off to the heat radiating body so that the adhesive layer is in contact with the heat radiating body, and is appropriately selected according to the purpose. can do.

Here, an example of the method for manufacturing the heat radiating component of the present invention will be described with reference to FIGS. 3A to 3D.
First, the heat conductive sheet 100 is prepared (FIG. 3A). The heat conductive sheet 100 here has the same structure as the heat conductive sheet 100 described with reference to FIG.
Next, the release film 3 is peeled from the heat conductive sheet 100 (FIG. 3B).
Next, the heat conductive sheet from which the release film 3 has been peeled off is attached to the heat radiating body 5 so that the adhesive layer 2 comes into contact with the heat radiating body 5 (FIGS. 3C and 3D).
From the above, heat dissipation parts can be obtained.

Hereinafter, specific examples of the present invention will be described. The present invention is not limited to these examples.

(Example 1)
<Manufacturing of heat conductive sheet body>
23% by volume of aluminum nitride particles having a volume average particle size of 1 μm and 20% by volume of alumina particles having a volume average particle size of 5 μm obtained by coupling a two-component addition reaction type liquid silicone resin with a silane coupling agent. A silicone composition (thermally conductive resin composition) was prepared by mixing 22% by volume of pitch-based carbon fibers having an average fiber length of 150 μm as a filler. The two-component addition reaction type liquid silicone resin contains polyorganosiloxane as a main component, and is contained in a silicone A agent containing polyorganosiloxane having a vinyl group as a main component and polyorganosiloxane having a vinyl group. The silicone B agent containing the polyorganosiloxane having a Si—H group was blended so that the blending volume ratio (agent A: agent B) was 17.5 vol%: 17.5 vol%. In the above, the volume% corresponds to the volume% in the obtained heat conductive sheet main body.
The obtained silicone composition was extruded into a hollow square columnar mold (50 mm × 50 mm) to form a 50 mm × 50 mm silicone molded product. A peel-treated film (peeling polyethylene terephthalate film) was attached to the inner wall of the mold so that the peel-treated surface was on the inside. The obtained silicone molded product was heated together with the mold in an oven at 100 ° C. for 6 hours to form a cured silicone product (thermally conductive molded product). The cured silicone product was taken out from the mold, and the peeled film was peeled off from the cured silicone product. Next, the cured silicone product was cut into a sheet with a slicer so that the average thickness was 0.5 mm. The molded product sheet obtained by slicing was sandwiched between release films and pressed under the conditions of a pressure of 0.5 MPa, a temperature of 87 ° C., and a time of 3 minutes to obtain a heat conductive sheet body.

<Formation of adhesive layer>
The release film on one surface (first surface) of the molded body sheet (heat conductive sheet body) after pressing was peeled off. Then, an acrylic adhesive liquid was spray-coated on the entire surface of the surface (first surface). Then, the acrylic adhesive liquid was spray-applied again (sprayed twice in total). Next, it was dried in the air at room temperature for 1 minute to form an adhesive layer on the entire surface of one surface (first surface).
The purchased acrylic adhesive was used.

<Attachment of release film>
As the first release film, a commercially available polyethylene terephthalate (PET) film (38 μm thickness) was coated with a silicone-based release agent to form a release layer, which was cut into 50 mm × 50 mm and used.
The first release film was attached to the entire surface of the first adhesive layer.

<Attachment of protective film>
As a protective film, a commercially available polyethylene terephthalate (PET) film (75 μm thickness) was coated with an acrylic pressure-sensitive adhesive to form an pressure-sensitive adhesive layer, which was cut into 50 mm × 50 mm and used.
The release film on the second surface opposite to the first surface on which the adhesive layer of the heat conductive sheet body was formed was peeled off. Then, a protective film was attached so as to be in contact with the entire surface of the second surface of the heat conductive sheet body.

From the above, a heat conductive sheet was obtained.

<Adhesiveness of protective film>
The adhesiveness of the protective film used was measured by the following method.
The above-mentioned heat conductive sheet with a protective film was attached to an aluminum plate (JISH4000 A5052P, manufactured by Engineering Test Service Co., Ltd.) and left at 25 ° C. for 24 hours. Then, a 90 ° peel test was carried out in accordance with JIS Z0237 at a peeling speed of 300 mm / min. As a result, the peel strength (adhesiveness) at the interface between the heat conductive sheet and the protective film was 0.2 N / 10 mm.

<Adhesiveness of heat conductive sheet>
The adhesiveness of the adhesive layer of the prepared heat conductive sheet was measured by the following method.
According to the above-mentioned method for producing a heat conductive sheet, the main body of the heat conductive sheet and the adhesive layer were formed. Then, the release film attached to the main body of the heat conductive sheet was peeled off, and the adhesive layer side was attached to an aluminum plate (JISH4000 A5052P, manufactured by Engineering Test Service Co., Ltd.). Further, a silicone / acrylic double-sided adhesive tape (NO.5302A manufactured by Nitto Denko) and a PET film were attached thereto, and the mixture was left at 25 ° C. for 24 hours. Then, a 90 ° peel test was performed in accordance with JISZ0237 at a peeling speed of 300 mm / min. As a result, the peel strength (adhesiveness) at the interface between the aluminum plate and the heat conductive sheet was 0.4 N / 10 mm.

(Example 2)
<Manufacturing of heat conductive sheet body>
33% by volume of silicone resin, 27% by volume of boron nitride having a scaly volume average particle size of 40 μm and 20% by volume of aluminum nitride having a volume average particle size of 1.2 μm, and a volume average particle size. A resin composition for forming a heat conductive sheet was prepared by uniformly mixing 19% by volume of 1 μm alumina particles and 1% by volume of a silane coupling agent. By the extrusion molding method, the resin composition for forming a heat conductive sheet is poured into a mold (opening: 50 mm × 50 mm) having a rectangular parallelepiped internal space, and heated in an oven at 60 ° C. for 4 hours to form a molded product. Formed a block. A peel-treated film (peeling polyethylene terephthalate film) was attached to the inner wall of the mold so that the peel-treated surface was on the inside. The obtained molded block was sliced into a sheet having a thickness of 0.15 mm with a slicer to obtain a heat conductive sheet in which scaly boron nitride was oriented in the thickness direction of the sheet. The obtained heat conductive sheet was sandwiched between the stripped polyethylene terephthalate films and pressed at 90 ° C., 0.5 MPa, and 3 minutes. Other than that, a heat conductive sheet was obtained under the same conditions as in Example 2.

(Comparative Example 1)
<Manufacturing of heat conductive sheet body>
The heat conductive sheet body was produced in the same manner as in the production of the heat conductive sheet body in Example 1.

<Formation of adhesive layer>
The adhesive layer was formed in the same manner as in the formation of the adhesive layer in Example 1.

<Attachment of release film>
The release film was attached in the same manner as in the case of the release film in Example 1.

<Formation of adhesive layer on the second surface side>
The release film on the second surface opposite to the first surface on which the adhesive layer of the heat conductive sheet body was formed was peeled off. Then, an acrylic adhesive liquid was spray-coated on the entire surface of the surface (second surface). Then, the acrylic adhesive liquid was spray-applied again (sprayed twice in total). Next, it was dried in the air at room temperature for 1 minute to form an adhesive layer on the entire surface of one surface (second surface).

<Attachment of protective film on the second surface side>
As a protective film, a commercially available polyethylene terephthalate (PET) film (75 μm thickness) was coated with an acrylic pressure-sensitive adhesive to form an pressure-sensitive adhesive layer, which was cut into 50 mm × 50 mm and used.
A protective film was attached to the entire surface of the adhesive layer on the second surface side.

From the above, the heat conductive sheet of Comparative Example 1 was obtained.
The layer structure of the obtained heat conductive sheet is shown in FIG.
The heat conductive sheet 101 of Comparative Example 1 has a heat conductive sheet main body 1, an adhesive layer 2, a release film 3, an adhesive layer 12, and a protective film 13.
The adhesive layer 2 is arranged in contact with the entire surface of the first surface 1a of the heat conductive sheet main body 1.
The release film 3 is arranged in contact with the entire surface of the adhesive layer 2 on the side opposite to the surface on the heat conductive sheet body 1 side.
The adhesive layer 12 is arranged in contact with the entire surface of the second surface 1b of the heat conductive sheet main body 1.
The protective film 13 is arranged in contact with the entire surface of the adhesive layer 12 on the side opposite to the surface on the heat conductive sheet body 1 side.
The adhesive layer 2 and the adhesive layer 12 are made of the same material and have the same thickness. Therefore, the adhesiveness of the adhesive layer 2 and the adhesiveness of the adhesive layer 12 are the same.

<Measurement of thermal resistance>
In order to confirm the effect on the thermal resistance, the thermal resistance [° C. Cm ^{2 / W] of the heat conductive sheet externally processed to 20 mmφ in consideration of the adhesive layer was set to 1 kg / cm 2} by a method based on ASTM-D5470. Measured under load. The results are shown in Table 1.
When measuring the thermal resistance, the release film and the protective film were peeled off.

実施例１及び２では、粘着層が熱伝導シート本体の片側にしかないために、粘着層が熱伝導シート本体の両側にある比較例１に比べて、熱抵抗が小さかった。
また、実施例１及び２では、粘着性が必要な面に粘着層を設け、更に粘着層に剥離フィルムを貼付しているため、タック性を有する熱伝導シート本体に直接に剥離フィルムを貼付する場合と比べ、取り扱い性に優れた。

In Examples 1 and 2, since the adhesive layer is only on one side of the heat conductive sheet body, the thermal resistance is smaller than that of Comparative Example 1 in which the adhesive layers are on both sides of the heat conductive sheet body.
Further, in Examples 1 and 2, since the adhesive layer is provided on the surface requiring adhesiveness and the release film is further attached to the adhesive layer, the release film is directly attached to the main body of the heat conductive sheet having tackiness. It was easier to handle than the case.

The heat conductive sheet of the present invention can be suitably used for manufacturing heat radiating parts.

1 Heat-conducting sheet body 1a First surface 1b Second surface 2 Adhesive layer 3 Peeling film 4 Protective film 5 Heat-dissipating body 100 Heat-conducting sheet 200 Heat-dissipating parts

Claims (11)

A heat conductive sheet body containing a heat conductive filler, which is used between an electronic component and a heat radiating body,
An adhesive layer arranged in contact with the entire surface of the first surface of the heat conductive sheet body,
A release film arranged in contact with the surface of the adhesive layer opposite to the surface of the heat conductive sheet main body, and
A peelable protective film arranged in contact with the entire surface of the second surface opposite to the first surface of the heat conductive sheet body, and
A heat conductive sheet characterized by having. The heat conductive sheet according to claim 1, wherein the adhesiveness between the heat conductive sheet main body and the adhesive layer is higher than the adhesiveness between the heat conductive sheet main body and the protective film. The heat conductive sheet according to any one of claims 1 to 2, wherein the adhesiveness between the heat conductive sheet main body and the protective film is higher than the adhesiveness between the adhesive layer and the release film. The heat conductive sheet according to any one of claims 1 to 3, wherein the adhesive layer is an acrylic adhesive layer. The heat conductive sheet body contains a binder resin and
The heat conductive sheet according to any one of claims 1 to 4, wherein the binder resin is a cured product of a silicone resin. The heat conductive sheet according to any one of claims 1 to 5, wherein the heat conductive filler contains at least one of carbon fiber and boron nitride. A process for manufacturing a heat conductive sheet body containing a heat conductive filler, which is used between an electronic component and a radiator, and a process for manufacturing the heat conductive sheet body.
An adhesive layer forming step of forming the adhesive layer so that the adhesive layer is in contact with the entire surface of the first surface of the heat conductive sheet body.
A release film arranging step of arranging the release film so that the release film is in contact with the surface of the adhesive layer on the side opposite to the surface of the heat conductive sheet main body.
A protective film arranging step of arranging the protective film so that the peelable protective film is in contact with the entire surface of the second surface opposite to the first surface of the heat conductive sheet body.
A method for producing a heat conductive sheet, which comprises. The method for producing a heat conductive sheet according to claim 7, wherein the pressure-sensitive adhesive layer forming step is performed by applying the pressure-sensitive adhesive composition to the entire surface of the first surface of the heat conductive sheet main body. A heat conductive sheet body containing a heat conductive filler, which is used between an electronic component and a heat radiating body,
An adhesive layer arranged in contact with the entire surface of the first surface of the heat conductive sheet body,
A peelable protective film arranged in contact with the entire surface of the second surface opposite to the first surface of the heat conductive sheet body, and
A heat radiating body arranged in contact with the surface of the adhesive layer opposite to the surface of the heat conductive sheet main body, and
A heat-dissipating component characterized by having. The heat radiating component according to claim 9, wherein the heat radiating body is any one of a heat spreader, a heat sink, a vapor chamber, and a heat pipe. A peeling step of peeling the release film of the heat conductive sheet according to any one of claims 1 to 6 from the adhesive layer.
A sticking step of attaching the heat conductive sheet from which the release film has been peeled off so that the adhesive layer is in contact with the heat radiating body, and a sticking step of sticking the heat conductive sheet to the heat radiating body.
A method for manufacturing a heat-dissipating component, which comprises.

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