JP5423455B2 - HEAT CONDUCTIVE SHEET, ITS MANUFACTURING METHOD, AND HEAT DISCHARGE DEVICE USING HEAT CONDUCTIVE SHEET - Google Patents

Description

  The present invention relates to a heat conductive sheet, a manufacturing method thereof, and a heat dissipation device using the heat conductive sheet.

  In recent years, the density of wiring and the mounting density of electronic components on multilayer wiring boards and semiconductor packages have increased, and the amount of heat generated per unit area has increased due to higher integration of semiconductor elements. There is a desire to improve.

  Generally, a heat dissipation device that dissipates heat by closely adhering a heat conductive grease or a heat conductive sheet between a heat generating element such as a semiconductor package and a heat dissipating element such as aluminum or copper is generally used. The heat conductive sheet is superior to the heat conductive grease in assembling the heat dissipation device. In order to improve heat dissipation, the thermal conductive sheet is required to have high thermal conductivity, but the thermal conductivity of the conventional thermal conductive sheet is not necessarily sufficient.

  Therefore, for the purpose of further improving the thermal conductivity of the thermal conductive sheet, a thermal conductive sheet has been proposed in which an inorganic powder having a large thermal conductivity is blended in the matrix material and further oriented perpendicularly to the sheet surface. Yes.

Patent Document 1 is a heat conductive sheet in which an inorganic filler (boron nitride) is oriented in a direction substantially perpendicular to the sheet surface. Patent Document 2 describes a structure in which carbon fibers dispersed in a gel material are oriented perpendicular to the sheet surface.
In either case, the surface of the sheet is exposed to a thermally conductive inorganic material, so the surface has low adhesiveness (tackiness), and it is difficult to temporarily fix it in the process of mounting between a heating element and a radiator such as aluminum or copper. There is a point that workability is bad. In Patent Document 1, a step of impregnating a plasticizer after slicing is also provided in order to avoid this, but the tackiness is improved because the binder resin is softened thereby, but there is a problem that the strength of the sheet is reduced, In addition, the plasticizer or the binder resin softened thereby covers the surface, and the thermal resistance tends to increase due to the influence of cutting the heat flow path.
In general, in the case of such a sheet, when the heat is applied for a long period of time, the plasticizer tends to volatilize, the sheet becomes hard and brittle due to the effect of aging of the binder resin, and the tackiness tends to be lost. If the sheet becomes hard and brittle and tackiness is lost, in the worst case, the sheet may tear off to the periphery, causing a short circuit accident, and the adhesiveness of the sheet cannot be maintained, and there is a possibility that heat dissipation cannot be maintained.

Japanese Patent Laid-Open No. 2002-26202 JP 2000-195998 A

  An object of the present invention is to provide a heat conductive sheet having high heat conductivity, high flexibility and tackiness, and having excellent heat resistance. Moreover, the objective of this invention is providing the manufacturing method from which the heat conductive sheet which has high heat conductivity, high softness | flexibility, and tackiness and is excellent in heat resistance is obtained. A further object of the present invention is to provide a highly reliable heat dissipating device having a high heat dissipating capability.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have incorporated a specific cross-linked cured product and a specific polymer compound into the composition of the heat conductive sheet. It has been found that a heat conductive sheet excellent in tackiness can be obtained.

That is, the present invention is as follows.
<1> Graphite particles or hexagonal boron nitride particles having a flaky shape, an elliptical shape, or a rod shape, and having a hexagonal plane in the crystal oriented in the plane direction of the scale, the major axis direction of the ellipsoid, or the major axis direction of the rod (A), a crosslinked cured product (B) of a poly (meth) acrylate polymer compound having a Tg of 50 ° C. or less, a weight average molecular weight of 5,000 to 100,000, and a Tg of 0 ° C. or less, A poly (meth) acrylate polymer compound (C) having no reactive functional group, and a heat conductive sheet comprising a composition comprising:
The heat conduction characterized in that the surface direction of the scale of the graphite particles or hexagonal boron nitride particles (A), the major axis direction of the ellipsoid or the major axis direction of the rod are oriented in the thickness direction of the heat conductive sheet. Sheet.
<2> The mass blending ratio of the crosslinked cured product (B) of the poly (meth) acrylate polymer compound and the poly (meth) acrylate polymer compound (C) is (B) :( C ) = 5: 5-7: 3,
The poly (meth) acrylate polymer compound (C) is present throughout the sheet material by internal addition, or the poly (meth) acrylate polymer compound (C) is 0.1 mg / thermally conductive sheet according to the <1>, characterized in that are coated or impregnated to the surface in an amount of cm ² or more 4 mg / cm ² or less.

<3> The thermal conductive sheet according to <1> or <2>, wherein the graphite (A) is expanded graphite and is contained in the sheet in an amount of 40% by mass to 85% by mass.
<4> The hexagonal boron nitride particles (A) are flaky hexagonal boron nitride particles, and are contained in the sheet in an amount of 40% by mass to 85% by mass. <1> Or the heat conductive sheet as described in <2>.

<5> The composition according to any one of <1> to <4>, wherein the composition contains a phosphate ester flame retardant (D) in a range of 10% by mass to 40% by mass. Heat conduction sheet.
<6> The above <1> to <5>, wherein the poly (meth) acrylate polymer compound (C) is applied on one surface or impregnated on one surface. The heat conductive sheet as described in any one of these.

<7> including the following steps (1a) to (4), the surface direction of the scale of graphite particles or hexagonal boron nitride particles (A), the major axis direction of the ellipsoid, or the major axis direction of the rod is a heat conductive sheet The manufacturing method of the heat conductive sheet orientated in the thickness direction.
(1a) Graphite particles or hexagonal boron nitride having a scale shape, an elliptical shape, or a rod shape, and a hexagonal plane in the crystal oriented in the plane direction of the scale, the major axis direction of the ellipse, or the major axis direction of the rod Particle (A), poly (meth) acrylate polymer compound (B ′) having a Tg of 50 ° C. or less, a curing agent (b) for crosslinking and curing the same, and a weight average molecular weight of 5,000 to 100,000 And a composition containing a poly (meth) acrylate polymer compound (C) having a Tg of 0 ° C. or less and having no reactive functional group, the graphite particles or hexagonal boron nitride. Roll forming, press forming, extrusion forming or coating to a thickness of 20 times or less of the mass average diameter of the particles (A), the graphite particles or hexagonal boron nitride particles (A) are in a substantially parallel direction with respect to the main surface. Producing an oriented primary sheet,
(2) A step of obtaining a molded body by laminating the primary sheet,
(3) heating the molded body to react the poly (meth) acrylate polymer compound (B ′) with the curing agent (b);
(4) A step of obtaining a sheet by slicing at an angle of 0 to 30 degrees with respect to a normal line emerging from the primary sheet surface.

<8> The surface direction of the scale of graphite particles or hexagonal boron nitride particles (A), the major axis direction of the ellipsoid, or the major axis direction of the rod, including the following steps (1b) to (5): The manufacturing method of the heat conductive sheet orientated in the thickness direction.
(1b) Graphite particles or hexagonal boron nitride having a scale shape, an elliptical shape, or a rod shape, and a hexagonal plane in the crystal oriented in the plane direction of the scale, the major axis direction of the ellipse, or the major axis direction of the rod A composition containing particles (A), a poly (meth) acrylate polymer compound (B ′) having a Tg of 50 ° C. or less, and a curing agent (b) for crosslinking and curing the composition, Rolled, pressed, extruded or coated to a thickness of 20 times or less the mass average diameter of the graphite particles or hexagonal boron nitride particles (A), and the graphite particles or hexagonal nitriding in a parallel direction with respect to the main surface Producing a primary sheet in which the boron particles (A) are oriented;
(2) A step of obtaining a molded body by laminating the primary sheet,
(3) heating the molded body to react the poly (meth) acrylate polymer compound (B ′) with the curing agent (b);
(4) A step of obtaining a sheet by slicing at an angle of 0 to 30 degrees with respect to a normal line emerging from the primary sheet surface;
(5) On at least one surface of the sheet, a poly (meth) acrylate polymer compound (C) having a weight average molecular weight of 5,000 to 100,000 and a Tg of 0 ° C. or less and having no reactive functional group. ) Is applied or impregnated.

<9> The heat conductive sheet according to any one of <1> to <6> or the heat conductive sheet obtained by the production method according to <7> or <8> A heat dissipating device characterized by being interposed therebetween.

The heat conductive sheet according to <1> is suitable for heat dissipation applications having high heat conductivity, high flexibility and tackiness, and excellent heat resistance.
Moreover, in addition to the effect of the invention described in <1>, the heat conductive sheet described in <2> can achieve higher tackiness.
In addition to the effects of the invention described in <1> or <2>, the thermal conductive sheet described in <3> and <4> can achieve higher thermal conductivity.
Moreover, in addition to the effect of the invention as described in any one of <1> to <4>, the heat conductive sheet according to <5> can impart flame retardancy and also achieve higher flexibility. it can.
In addition to the effects of the invention described in any one of <1> to <5>, the heat conductive sheet described in <6> can have a strong tack on only one surface, so When attaching and removing the kimono, it is fixed to the strong tack surface, so it is easy to handle.

In addition, the method for producing a heat conductive sheet according to the above <7>, a heat conductive sheet having high heat conductivity, high flexibility and tackiness, and having excellent heat resistance, is improved in productivity, cost and energy efficiency. Advantageous and reliable in terms of production.
In addition to the effect of the invention described in <7>, the method for producing a heat conductive sheet described in <8> can have a strong tack on only one surface, so that both-surface adherends are attached. When it is removed or removed, it is fixed to the strong tack surface side, so that it is possible to manufacture a heat conductive sheet having excellent handling properties.
Furthermore, the heat dissipating device according to <9> has a high heat dissipating capability over a long period of time.

<Heat conduction sheet>
The heat conductive sheet of the present invention is a scaly, oval or rod-like shape, and the hexagonal plane in the crystal is oriented in the plane direction of the scaly, the major axis direction of the ellipse or the major axis direction of the rod, or hexagonal Crystalline boron nitride particles (A), an organic polymer compound (B) having a Tg of 50 ° C. or less, a weight average molecular weight of 5,000 to 100,000, and a Tg of 0 ° C. or less, having a reactive functional group A composition containing a poly (meth) acrylic acid ester polymer compound (C) not to be used.
The scale surface direction of the graphite particles or hexagonal boron nitride particles (A), the major axis direction of the ellipse or the major axis direction of the rod are oriented in the thickness direction of the heat conductive sheet.

  The shape of the graphite particles or hexagonal boron nitride particles (A) in the present invention is scaly, oval or rod-like, and scaly is particularly preferable. When the shape of the graphite particles or hexagonal boron nitride particles (A) is spherical or indefinite, the thermal conductivity is inferior. When the shape is fibrous, it is difficult to form into a sheet and the productivity is inferior.

The hexagonal plane in the crystal is oriented in the scale direction, the long axis direction of the ellipse or the long axis direction of the rod, and can be confirmed by X-ray diffraction measurement.
The orientation direction of the hexagonal plane in the crystal of graphite particles or hexagonal boron nitride particles (A) is specifically confirmed by the following method.
First, the scale direction of the graphite particles or hexagonal boron nitride particles (A), the major axis direction of the ellipsoid, or the major axis direction of the rod are oriented substantially parallel to the plane direction of the sheet or film. A measurement sample sheet is prepared. As a specific method for preparing the sample sheet for measurement, a mixture of 10% by volume or more of graphite particles or hexagonal boron nitride particles and a resin is formed into a sheet. The “resin” used here is a resin corresponding to a composition containing a cross-linked cured product (B) of a poly (meth) acrylate polymer compound and a poly (meth) acrylate polymer (C). However, a material that does not show a peak that hinders X-ray diffraction, such as an amorphous resin, or a material that can be shaped can be used without using a resin. The operation of pressing the mixture sheet to 1/10 or less of the original thickness, laminating the pressed sheets, and further crushing the laminate to 1/10 or less is repeated three or more times. By this operation, in the prepared measurement sample sheet, the surface direction of the scale of the graphite particles or hexagonal boron nitride particles (A), the major axis direction of the ellipse, or the major axis direction of the rod is the same as that of the measurement sample sheet. It is in a state of being oriented substantially parallel to the surface direction.

In the case of graphite particles, when the X-ray diffraction measurement is performed on the surface of the measurement sample sheet prepared as described above, the peak height corresponding to the (110) plane of graphite appearing near 2θ = 77 ° is obtained. The value divided by the height of the peak corresponding to the (002) plane of graphite appearing around 2θ = 27 ° is 0 to 0.02. The same applies to the case of hexagonal boron nitride particles. When X-ray diffraction measurement is performed, the peak height corresponding to the (110) plane of hexagonal boron nitride particles appearing in the vicinity of 2θ = 77 ° is 2θ. The value divided by the height of the peak corresponding to the (002) plane of hexagonal boron nitride appearing around = 27 ° is 0 to 0.02.
Thus, in the present invention, "the hexagonal plane in the crystal is oriented in the plane direction of the scale, the major axis direction of the ellipse or the major axis direction of the rod" means that the graphite particles or hexagonal boron nitride particles Graphite or hexagonal that appears in the vicinity of 2θ = 77 ° by performing X-ray diffraction measurement on the surface of a sheet of a composition containing a cross-linked cured product of (A) and a poly (meth) acrylate polymer compound. The value obtained by dividing the height of the peak corresponding to the (110) plane of crystalline boron nitride by the height of the peak corresponding to the (002) plane of graphite or hexagonal boron nitride near 2θ = 27 ° is 0 to It means a state that becomes 0.02.

  Examples of the graphite particles used in the present invention include flaky, oval or rod-like graphite particles such as flaky graphite particles, artificial graphite particles, exfoliated graphite particles, acid-treated graphite particles, expanded graphite particles, and carbon fiber flakes. Can be used. Examples of the hexagonal boron nitride particles used in the present invention include plate-like boron nitride particles and scaly boron nitride particles.

In particular, those which are likely to become scaly graphite particles when mixed with a crosslinked cured product (B) of a poly (meth) acrylate polymer compound are preferred. Specifically, flake graphite particles such as exfoliated graphite particles and expanded graphite particles are more preferable because they can be easily oriented, the interparticle contact is easily maintained, and high thermal conductivity is easily obtained.
In the case of hexagonal boron nitride particles, an anisotropic shape such as a scale shape or a flake shape is preferable.
In the heat conductive sheet of the present invention, in terms of heat conductivity, graphite particles are preferable because they have a heat conductivity of about 5 to 10 times that of hexagonal boron nitride particles. On the other hand, in applications where electrical insulation is required, hexagonal boron nitride particles are preferred because graphite particles have electrical conductivity.

The mass average diameter of the graphite particles or hexagonal boron nitride particles (A) is not particularly limited, but is preferably 0.05 to 2 mm, more preferably 0.1 to 1.0 mm, from the viewpoint of improving thermal conductivity. Especially preferably, it is 0.2-0.5 mm.
The mass average diameter is measured as follows.
“Mass average diameter” is a value obtained by measuring the particle diameter of graphite particles or hexagonal boron nitride particles, and means a diameter at which the cumulative mass reaches 50% when a cumulative mass distribution curve is obtained by classification with a sieve or the like.

  The content of the graphite particles or hexagonal boron nitride particles (A) is not particularly limited, but is preferably 40% by mass or more and 85% by mass or less, and 45% by mass or more and 75% by mass or less of the total volume of the composition. It is more preferable. When the content of the graphite particles or hexagonal boron nitride particles (A) is less than 40% by mass, the thermal conductivity tends to decrease, and when the content exceeds 85% by mass, sufficient flexibility and adhesion, In addition, the tackiness tends to be difficult to obtain.

In addition, the content (volume%) of the graphite particles or the hexagonal boron nitride particles (A) in the present specification is a value obtained by the following formula.
Content of graphite particles or hexagonal boron nitride particles (A) (% by volume) = (Aw / dA) / ((Aw / Ad) + (Bw / Bd) + (Cw / Cd) + (Dw / Dd) + ...) × 100
Aw: mass composition (mass%) of graphite particles or hexagonal boron nitride particles (A)
Bw: Mass composition (% by mass) of a crosslinked cured product (B) of a poly (meth) acrylic acid ester polymer compound having a Tg of 50 ° C. or lower.
Cw: mass composition (% by mass) of poly (meth) acrylate polymer compound (C) having no reactive functional group
Dw: mass composition (mass%) of other optional components (D) such as phosphate ester flame retardants
Ad: Specific gravity of graphite particles or hexagonal boron nitride particles (A) (In the present invention, Ad is calculated in the case of graphite: 2.1, in the case of hexagonal boron nitride: 2.3)
Bd: Specific gravity of cross-linked cured product (B) of poly (meth) acrylate polymer compound having Tg of 50 ° C. or less Cd: Poly (meth) acrylate polymer compound having no reactive functional group ( C) Specific gravity Dd: Specific gravity of other optional component (D) such as phosphate ester flame retardant

In the present invention, (Bw / Bd) is obtained from the following equation.
(Bw / Bd) = (B′w / B′d) + (bw / bd)
B′w: Mass composition (% by mass) of poly (meth) acrylic acid ester polymer compound (B ′) having a Tg of 50 ° C. or less
bw: mass composition (% by mass) of the curing agent (b)
B′d: Specific gravity of poly (meth) acrylate polymer compound (B ′) having Tg of 50 ° C. or less bd: Specific gravity of curing agent (b)

The cross-linked cured product (B) of the poly (meth) acrylate polymer compound in the present invention has a Tg (glass transition temperature) of 50 ° C. or lower, preferably −70 to 20 ° C., more preferably −60 to 0 ° C. It is. When the Tg exceeds 50 ° C., the flexibility is inferior, and the adhesion to the heat generator and the heat radiator is poor.
The Tg of the cross-linked cured product (B) of the poly (meth) acrylate polymer compound is equal to the Tg of the poly (meth) acrylate polymer compound (B ′) as the raw material of the cross-linked cured product (B). It is almost the same.
The glass transition temperature (Tg) is measured by a differential scanning calorimeter (DSC).

  The cross-linked cured product (B) of the poly (meth) acrylate polymer compound in the present invention is obtained by curing the poly (meth) acrylate polymer compound (B ′) with a curing agent (b). .

Examples of the poly (meth) acrylate polymer compound (B ′) used in the present invention include, for example, butyl acrylate, 2-ethylhexyl acrylate and the like as main raw material components, and (meth) acrylic acid, (meth A poly (meth) acrylate polymer compound (so-called acrylic rubber) in which a reactive functional group is introduced by copolymerizing hydroxyethyl acrylate, glycidyl (meth) acrylate, or the like is preferably used.
Examples of the curing agent (b) for curing this include polyfunctional epoxy, polyfunctional isocyanate, polyfunctional amine, imidazole, and a compound having a plurality of phenolic hydroxyl groups.
In particular, butyl acrylate or 2-ethylhexyl acrylate is copolymerized with a (meth) acrylic acid ester monomer containing 70% by mass to 99% by mass of (meth) acrylic acid in an amount of 1% by mass to 10% by mass. The polymerized product is a poly (meth) acrylic acid ester polymer compound (B ′), and a crosslinked cured product (B) obtained using a polyfunctional epoxy as a curing agent (b) has an appropriate reaction rate during production. The point of the balance of the softness | flexibility and intensity | strength of an obtained sheet | seat and intensity | strength is favorable, and preferable.
In addition, the glass transition temperature of the crosslinked cured product (B) tends to decrease as the amount of copolymer components such as butyl acrylate or 2-ethylhexyl acrylate increases. Therefore, what is necessary is just to adjust the quantity of these copolymerization components suitably so that the glass transition temperature of bridge | crosslinking hardened | cured material (B) may be 50 degrees C or less.

The content of the cross-linked cured product (B) of the poly (meth) acrylate polymer compound in the heat conductive sheet of the present invention is not particularly limited, but the poly (meth) acrylate polymer compound (C) is contained inside. When added, it is preferably 10% by mass to 30% by mass, and more preferably 12% by mass to 25% by mass with respect to the total volume of the composition. When the poly (meth) acrylate polymer compound (C) is applied or impregnated on the sheet surface, the application amount or impregnation amount is preferably 0.1 to 4 mg / cm ² , more preferably 0. it is a 2~3mg / cm ^2. If the coating amount or impregnation amount is 0.1 mg / cm ² or more, sufficient tackiness can be easily obtained, and if it is 4 mg / cm ² or less, the thermal conductivity tends to control the decrease.
In addition, the content ratio of the crosslinked cured product (B) of the poly (meth) acrylate polymer compound and the poly (meth) acrylate polymer compound (C) will be described later.

The poly (meth) acrylic acid ester polymer compound (C) in the present invention contains, for example, butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate and the like as main raw material components, and (meth) acrylic as necessary. A poly (meth) acrylic acid ester polymer compound (so-called acrylic rubber) obtained by copolymerizing methyl acid or the like is preferably used.
In the heat conductive sheet of the present invention, the poly (meth) acrylate polymer compound (C) is present in the entire sheet material by internal addition, or 0.1 mg / cm ² or more and 4 mg / cm ² or less. When the surface is applied or impregnated with the amount, the heat conductive sheet has excellent tackiness. More specifically, for example, when slicing a molded body in the production of a heat conductive sheet, graphite particles or hexagonal boron nitride particles may be cleaved during slicing to cover the sheet surface. Although the tackiness of the sheet tends to decrease, the poly (meth) acrylate polymer compound (C) in the present invention oozes out and contributes to the tackiness of the heat conductive sheet.
The weight average molecular weight needs to be 5000 or more and 100000 or less, and when the weight average molecular weight is less than 5000, there is no effect of improving tackiness and the strength tends to decrease. When the weight average molecular weight exceeds 100,000, there is no effect of improving tackiness and flexibility. More preferably, it is 6000 or more and 10,000 or less.

The poly (meth) acrylic acid ester polymer compound (C) needs to have a Tg of 0 ° C. or lower. When Tg exceeds 0 ° C., there is no effect of improving tackiness and flexibility. More preferably, it is −30 ° C. or lower. It is necessary to have no reactive functional groups such as glycidyl group, hydroxyl group, and carboxyl group, and if these are present, tackiness and flexibility cannot be maintained for a long time, or tackiness and flexibility may be reduced due to thermal history. Tend to.
In order to set the weight average molecular weight of the poly (meth) acrylic acid ester polymer compound (C) to 5,000 or more and 100,000 or less, for example, by the solution polymerization method, the amount of the polymerization initiator, the amount of the chain transfer agent, the polymerization temperature, etc. May be adjusted as appropriate.
The Tg of the poly (meth) acrylate polymer compound (C) can be adjusted by the monomer composition ratio. If there are many homopolymers with low Tg such as butyl acrylate (Tg of homopolymer is about -50 ° C) and 2-ethylhexyl acrylate (Tg of homopolymer is about -60 ° C) in the monomer composition, the Tg of the resulting polymer The higher the Tg of homopolymers, such as methyl methacrylate (the homopolymer Tg is about 100 ° C.), the higher the Tg of the resulting polymer, so that the Tg is 0 ° C. or less due to the monomer composition. adjust.

  The poly (meth) acrylate polymer compound (C) used in the present invention may be present throughout the heat conductive sheet material by internal addition, but is localized on the surface by coating or impregnating on the surface. In particular, when one surface is coated or impregnated on one surface, strong tackiness can be imparted only to one surface, which is preferable in terms of obtaining a sheet with good handling properties.

The content of the poly (meth) acrylate polymer compound (C) used in the present invention is not particularly limited. However, in the case of internal addition, a crosslinked cured product of poly (meth) acrylate polymer compound (B ) And the poly (meth) acrylic acid ester polymer compound (C) in a mass blending ratio of (B) :( C) = 5: 5 to 7: 3 is preferable.
When the ratio of (C) is smaller than (B) :( C) = 7: 3, there is a tendency that sufficient tackiness is difficult to obtain, and the ratio of (C) from (B) :( C) = 5: 5. When there is much, there exists a tendency for the intensity | strength of a sheet | seat to fall. A more preferable range is (B) :( C) = 5.5: 4.5 to 6.5: 3.5.
Moreover, when apply | coating or impregnating to the surface, it is preferable to apply | coat or impregnate the quantity of 0.1 mg / cm < ² > or more and 4 mg / cm < ² > or less. If it is less than 0.1 mg / cm ^2, it tends to be difficult to obtain sufficient tackiness, and if it exceeds 4 mg / cm ² , the thermal conductivity tends to decrease.
In the heat conductive sheet of the present invention, the poly (meth) acrylate polymer compound (C) is applied to the sheet surface while the poly (meth) acrylate polymer compound (C) is internally added. Alternatively, it may be impregnated. Preferred content of poly (meth) acrylate polymer compound (C) and coating when poly (meth) acrylate polymer compound (C) is coated or impregnated on the sheet surface while internally added The amount or impregnation amount is the same as the above range.

  In the heat conductive sheet of the present invention, the poly (meth) acrylate polymer compound (C) is added to one surface of the sheet while the poly (meth) acrylate polymer compound (C) is internally added. Application or impregnation is also preferred. Also in the case of this configuration, the preferable content, coating amount or impregnation amount of the poly (meth) acrylic acid ester polymer compound (C) is the same as the above range.

Moreover, the heat conductive sheet of this invention can contain a flame retardant. It does not specifically limit as a flame retardant, For example, a red phosphorus flame retardant and a phosphate ester flame retardant can be contained.
Examples of red phosphorus flame retardants include pure red phosphorus powder, various coatings for the purpose of improving safety and stability, and master batches. Examples include trade names: Nova Red, Nova Excel, Nova Quel, Nova Pellet, etc., manufactured by Rin Chemical Industry Co., Ltd.

  Examples of the phosphate ester flame retardant include aliphatic phosphate esters such as trimethyl phosphate, triethyl phosphate, tributyl phosphate; triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, trixylenyl phosphate, cresyl-2, Aromatic phosphate esters such as 6-xylenyl phosphate, tris (t-butylated phenyl) phosphate, tris (isopropylated phenyl) phosphate, triaryl isopropylate; resorcinol bisdiphenyl phosphate, bisphenol A bis (diphenyl phosphate) ), Aromatic condensed phosphoric acid esters such as resorcinol bis-dixylenyl phosphate; and the like. These may be used alone or in combination of two or more. Among these, a liquid phosphate ester flame retardant is preferable because it contributes to the flexibility of the sheet.

  The content of the flame retardant is not particularly limited, but is preferably 10 to 40% by mass, more preferably 15 to 30% by mass with respect to the total volume of the composition. If the content of the flame retardant is within the above range, it is preferable because sufficient flame retardancy is exhibited and it is advantageous in terms of flexibility. When the content of the flame retardant is less than 10% by mass, it is difficult to obtain sufficient flame retardancy, and when it exceeds 40% by mass, the sheet strength tends to decrease.

  In addition, the heat conductive sheet of the present invention is further provided with a toughness improving agent such as urethane acrylate; a hygroscopic agent such as calcium oxide or magnesium oxide; an adhesive strength such as a silane coupling agent, a titanium coupling agent, or an acid anhydride. An improvement agent; a wetting improvement agent such as a nonionic surfactant or a fluorine-based surfactant; an antifoaming agent such as silicone oil; an ion trapping agent such as an inorganic ion exchanger; or the like can be appropriately added.

  In the heat conductive sheet of the present invention, the surface direction of the scale of the graphite particles or hexagonal boron nitride particles (A), the long axis direction of the ellipse or the long axis direction of the rod are oriented in the thickness direction of the heat conductive sheet. Without this orientation, sufficient thermal conductivity cannot be obtained.

  In the present invention, “orientation in the thickness direction of the heat conduction sheet” means that a cross section in the thickness direction of the heat conduction sheet is observed using a SEM (scanning electron microscope), and any 50 graphite particles or hexagonal crystal nitride An angle with respect to the heat conduction sheet surface in the major axis direction from the direction in which the elementary particles are visible (a complementary angle is adopted when 90 degrees or more) is measured, and the average value is in a range of 60 to 90 degrees. .

  Moreover, in the heat conductive sheet of this invention, in order to protect an adhesive surface, the adhesive surface of the heat conductive sheet before use may be covered with the protective film. Examples of the material for the protective film include resins such as polyethylene, polyester, polypropylene, polyethylene terephthalate, polyimide, polyetherimide, polyether naphthalate, and methylpentene film, and metals such as coated paper, coated cloth, and aluminum. Two or more kinds of these protective films may be combined to form a multilayer film, and a protective film whose surface is treated with a release agent such as silicone or silica is preferably used.

<The manufacturing method of a heat conductive sheet>
The manufacturing method of the heat conductive sheet of this invention includes the process of producing a primary sheet, the process of obtaining this molded object by laminating | stacking this primary sheet, and the process of slicing this molded object.
The manufacturing method of the heat conductive sheet of this invention includes the following process (1a)-(4) or (1b)-(5). Further, the following steps (1a) to (4) may further include (5).
First method:
(1a) Graphite particles or hexagonal boron nitride having a scale shape, an elliptical shape, or a rod shape, and a hexagonal plane in the crystal oriented in the plane direction of the scale, the major axis direction of the ellipse, or the major axis direction of the rod Particle (A), poly (meth) acrylate polymer compound (B ′) having a glass transition temperature of 50 ° C. or less, a curing agent (b) for crosslinking and curing the same, and a weight average molecular weight of 5000 A composition containing a poly (meth) acrylate polymer compound (C) having a 100,000 or less and Tg of 0 ° C. or less and having no reactive functional group, the graphite particles or hexagonal crystals. Rolled, pressed, extruded or coated to a thickness of 20 times or less the mass average diameter of boron nitride particles (A), and graphite particles or hexagonal boron nitride particles (A) in a direction parallel to the main surface For producing a primary sheet oriented with .
(2) A step of laminating the primary sheets to obtain a molded body.
(3) The process which heats the said molded object and makes the said poly (meth) acrylic-ester type polymer compound (B ') and a hardening | curing agent (b) react.
(4) A step of obtaining a sheet by slicing at an angle of 0 to 30 degrees with respect to a normal line emerging from the primary sheet surface.

Second method:
(1b) Graphite particles or hexagonal boron nitride having a scale shape, an elliptical shape, or a rod shape, and a hexagonal plane in the crystal oriented in the plane direction of the scale, the major axis direction of the ellipse, or the major axis direction of the rod A composition comprising particles (A), a poly (meth) acrylate polymer compound (B ′) having a glass transition temperature of 50 ° C. or less, and a curing agent (b) for crosslinking and curing the same. Is rolled, press-molded, extruded or coated to a thickness of 20 times or less the mass average diameter of the graphite particles or hexagonal boron nitride particles (A), and the graphite particles or A step of producing a primary sheet in which hexagonal boron nitride particles (A) are oriented.
(5) On at least one surface of the sheet, a poly (meth) acrylate polymer compound (C) having a weight average molecular weight of 5,000 to 100,000 and a Tg of 0 ° C. or less and having no reactive functional group. ) Is applied or impregnated.

Hereinafter, each step will be described.
(1a) Production process of primary sheet First, graphite particles or hexagonal boron nitride particles (A), poly (meth) acrylate polymer compound (B '), and a curing agent (b) ) And a poly (meth) acrylic ester polymer compound (C). The composition can be obtained by mixing them, but the mixing method is not particularly limited. For example, a poly (meth) acrylate polymer compound (B ′) is dissolved in a solvent, graphite particles or hexagonal boron nitride particles (A) and other components are added thereto, and the mixture is stirred and dried. Or roll kneading, mixing by a kneader, mixing by a brabender, mixing by an extruder, or the like can be used.
In this mixing, the poly (meth) acrylate polymer compound (B ′) and the curing agent (b) in the composition are unreacted.

Next, the composition is rolled, press-molded, extruded or coated to a thickness of 20 times or less the mass average diameter of the graphite particles or hexagonal boron nitride particles (A), and in a direction substantially parallel to the main surface. A primary sheet in which graphite particles or hexagonal boron nitride particles (A) are oriented is prepared.
The thickness when the composition is formed into a primary sheet is 20 times or less, preferably 2 to 0.2 times the mass average diameter of the graphite particles or hexagonal boron nitride particles (A). When the thickness exceeds 20 times the average value of the major axis of the graphite particles or hexagonal boron nitride particles (A), the orientation of the graphite particles or hexagonal boron nitride particles (A) becomes insufficient, resulting in As a result, the thermal conductivity of the finally obtained thermal conductive sheet tends to deteriorate.

The composition is rolled, pressed, extruded, or coated to produce a primary sheet in which graphite particles or hexagonal boron nitride particles (A) are oriented in a direction substantially parallel to the main surface, Roll forming or press forming is preferable because the graphite particles or hexagonal boron nitride particles (A) can be easily oriented.
The state in which the graphite particles or hexagonal boron nitride particles (A) are oriented in a direction substantially parallel to the main surface of the sheet means that the graphite particles or hexagonal boron nitride particles (A) are in contact with the main surface of the sheet. The state is oriented as shown. The orientation of the graphite particles or hexagonal boron nitride particles (A) in the sheet plane is controlled by adjusting the flowing direction of the composition when the composition is molded. That is, by adjusting the direction of passing the composition through a rolling roll, the direction of extruding the composition, the direction of coating the composition, and the direction of pressing the composition, graphite particles or hexagonal boron nitride particles (A) The direction of is controlled.
Since the graphite particles or the hexagonal boron nitride particles (A) are basically anisotropic particles, the graphite particles are usually formed by rolling, pressing, extrusion, or coating the composition. Alternatively, the hexagonal boron nitride particles (A) are arranged in the same direction.

  When producing the primary sheet, the graphite particles or hexagonal boron nitride particles (A) and the poly (meth) acrylate polymer compound (B ′), a curing agent (b) for crosslinking and curing the same, When the composition before molding of the composition containing the poly (meth) acrylate polymer compound (C) is a lump, the thickness of the primary sheet after moulding with respect to the lump thickness (d0) Thickness with respect to the lateral width (W) of the primary sheet by rolling, pressing or extruding so that (dp) becomes dp / d0 <0.15, or by adjusting the shape corresponding to the cross-sectional shape of the primary sheet at the exit of the extruder. Extrusion molding is preferably performed so that (dp ′) satisfies dp ′ / W <0.15. By shaping so that dp / d0 <0.15, the graphite particles or hexagonal boron nitride particles (A) can be easily oriented in a direction substantially parallel to the main surface of the sheet.

(1b) Production step of primary sheet In the case of (1b), except that the composition is obtained without containing the poly (meth) acrylate polymer compound (C) in the same manner as in the step (1a). Obtain a primary sheet.

(2) Step of obtaining a molded body Next, the primary sheet is laminated to obtain a molded body. The method of laminating the primary sheet is not particularly limited, and examples thereof include a method of laminating a plurality of primary sheets, a method of folding the primary sheet, and the like. When laminating, the orientation of graphite particles or hexagonal boron nitride particles (A) in the sheet plane is aligned. The shape of the primary sheet at the time of lamination is not particularly limited. For example, when a rectangular primary sheet is laminated, a prismatic shaped body is obtained, and when a circular primary sheet is laminated, a cylindrical shape is obtained. A molded body is obtained.
Instead of the method of laminating a plurality of primary sheets and the method of folding the primary sheet, it is possible to obtain a molded body by winding the primary sheet. The method for winding the primary sheet is not particularly limited, and the primary sheet may be wound around the orientation direction of the graphite particles (A). The shape of the winding is not particularly limited, and may be, for example, a cylindrical shape or a rectangular tube shape.

  The pressure at the time of laminating the primary sheet is weak enough that the sliced surface is not crushed and falls below the required area for the convenience of slicing at an angle of 0 to 30 degrees with respect to the normal line coming out from the primary sheet surface in the subsequent process. And it adjusts so that it may become strong to such an extent that it adhere | attaches between sheets well. Usually, this adjustment can provide a sufficient adhesive force between the laminated surfaces, but if insufficient, lamination may be performed after thinly applying a solvent or an adhesive to the primary sheet. Moreover, you may perform lamination | stacking under a heating suitably.

(3) Step of heating the molded body Next, the molded body is heated, and the poly (meth) acrylate polymer compound (B ′) and a curing agent (b) that crosslinks and cures the poly (meth) acrylate polymer compound (B ′). It is made to react and it is set as the crosslinked hardened | cured material (B) of a poly (meth) acrylic-ester type | system | group polymer compound.
The preferred heating conditions vary depending on the type and concentration of the poly (meth) acrylic acid ester polymer compound (B ′) and the curing agent (b) that crosslinks and cures it. It is preferable to continue heating until the rate change becomes 15% / h or less. If the heating is stopped when the change in elastic modulus exceeds 15% / h, the reaction recurs due to heating during use, and the elastic modulus increases significantly, resulting in poor heat resistance when the resulting sheet is used. Tend.
The change in the elastic modulus is measured as follows.
The determination of the heating conditions such that the change in elastic modulus is 15% or less is performed as follows. A small amount of the same composition as the sheet is sampled and pressed into a 0.5 mm thick sample sheet, which is punched into 1 cm × 5 cm, and the sample sheet is cured by varying the temperature and time. Specifically, a cured sample sheet is produced by curing the curing time at 1 hour intervals at each heating temperature.
Each cured sample sheet prepared by crosslinking and curing under a plurality of conditions is left in an environment at a temperature of 25 ± 1 ° C. for 1 hour, and a tensile elastic modulus test is performed on each cured sample sheet to obtain an elastic modulus. The difference in elastic modulus (also referred to as “elastic modulus change”) of two cured sample sheets obtained by curing for one hour is obtained, and the curing conditions for which the difference is 15% or less are determined as the actual thermal conductive sheet. It is set as a cross-linking curing condition during production.
In this way, the crosslinking and curing conditions can be optimized by obtaining in advance the heating (curing) conditions at which the change in elastic modulus is 15% or less and heating the molded body under those conditions.
The elastic modulus is measured, for example, using STROGRAP ES manufactured by Toyo Seiki Seisakusho Co., Ltd. at a temperature of 25 ° C. and a tensile speed of 5 mm / min.

(4) Slicing step Next, the molded body was sliced at an angle of 0 to 30 degrees, preferably at an angle of 0 to 15 degrees with respect to the normal line coming out of the primary sheet surface, and had a predetermined thickness. A heat conductive sheet is obtained. When the slicing angle exceeds 30 degrees, the thermal conductivity tends to decrease.
When the molded body is a laminated body, it may be sliced so as to be perpendicular or substantially perpendicular to the lamination direction of the primary sheet. Further, when the molded body is a wound body, it may be sliced so as to be perpendicular or almost perpendicular to the winding axis. Further, in the case of a cylindrical molded body in which circular primary sheets are laminated, the molded body may be sliced like a wig within the above angle range.

  The slicing method is not particularly limited, and examples thereof include a multi-blade method, a laser processing method, a water jet method, and a knife processing method. The knife processing method is preferable because the thickness of the heat conductive sheet can be easily kept parallel. The cutting tool for slicing is not particularly limited, but it is difficult to disturb the orientation of the graphite particles or hexagonal boron nitride particles in the vicinity of the surface of the heat conductive sheet from which a slicer with a sharp blade, canna, etc. is obtained, And since a thin heat conductive sheet is also easy to produce, it is preferable.

  The slicing is preferably performed in a temperature range of Tg + 5 ° C. to Tg + 50 ° C. of the crosslinked cured product (B) of the poly (meth) acrylate polymer compound, and is performed in a temperature range of Tg + 10 ° C. to Tg + 40 ° C. Is more preferable. When the temperature at the time of slicing exceeds Tg + 50 ° C. of the cross-linked cured product (B) of the poly (meth) acrylate polymer compound, the molded article becomes soft and difficult to slice, or graphite particles or hexagonal The orientation of the crystalline boron nitride particles tends to be disturbed. On the other hand, when the temperature is lower than Tg + 5 ° C., the molded body becomes hard and brittle, and it becomes difficult to slice, or the sheet tends to be easily broken immediately after slicing.

  Although the thickness of a heat conductive sheet is suitably set by a use etc., Preferably it is 0.05-3 mm, More preferably, it is 0.1-1 mm. When the thickness of the heat conductive sheet is less than 0.05 mm, handling as a sheet tends to be difficult, and when it exceeds 3 mm, the heat dissipation effect tends to be low. The slice width of the molded body is the thickness of the heat conductive sheet, and the slice surface is a contact surface of the heat conductive sheet with the heat generating body or the heat radiating body.

(5) Step of applying or impregnating the poly (meth) acrylate polymer compound (C) Even when the primary sheet is obtained in the step (1a) or the step (1b), it is obtained. When at least one side of the sheet is coated or impregnated with the poly (meth) acrylic acid ester polymer compound (C), a sheet with good handling property having a strong tack only on one side or both sides is obtained. preferable. There are no particular restrictions on the method of application or impregnation. Specifically, various methods such as spray coating, printing, coating, transfer, and brushing can be used. However, when diluting with a solvent or the like for easy application, it is necessary to select one that does not attack the sheet substrate. From this viewpoint, in this case, it is preferable to emulsify in a medium mainly composed of water. Moreover, since the applied poly (meth) acrylic acid ester polymer compound (C) is leveled and fills the voids of the base material when a process of heating to about 50 to 120 ° C. is performed after coating, It is preferable in terms of thermal conductivity.
The method of impregnating one side is not limited as long as it can be impregnated on one side, but for example, a compound is placed on one side as in coating and impregnated, only one side is immersed in the liquid level, or a frame around the sheet Examples thereof include a method of providing a material and impregnating only one side.

<Heat dissipation device>
The heat radiating device of the present invention is obtained by interposing the heat conductive sheet of the present invention or the heat conductive sheet obtained by the manufacturing method of the present invention between the heat generating body and the heat radiating body. The heating element preferably has a surface temperature not exceeding 200 ° C. When the surface temperature is likely to exceed 200 ° C., for example, near the nozzle of a jet engine, around the inside of a kiln pot, around the inside of a blast furnace, around the inside of a nuclear reactor, the outer shell of a spacecraft, etc. It is not suitable because the organic polymer compound in the conductive sheet or the heat conductive sheet obtained by the production method of the present invention is likely to be decomposed. The temperature range in which the heat conductive sheet of the present invention or the heat conductive sheet manufactured by the manufacturing method of the present invention can be used particularly preferably is −10 to 120 ° C., and a heating element suitable for semiconductor packages, displays, LEDs, electric lamps, etc. As an example.

  On the other hand, as a heat sink, for example, a heat sink using aluminum, copper fins, plates, etc., an aluminum or copper block connected to a heat pipe, an aluminum or copper that circulates cooling liquid with a pump inside A typical example is a block, a Peltier element, and an aluminum or copper block having the same.

  The heat dissipation device of the present invention is established by bringing each surface of the heat conductive sheet of the present invention or the heat conductive sheet obtained by the manufacturing method of the present invention into contact with the heat generator and the heat radiator. There is no limitation on the contact method as long as the heating element, the heat conductive sheet, and the heat dissipation element can be fixed in a sufficiently adhered state, but from the viewpoint of maintaining the adhesion, a method of screwing through a spring, a clip A contact method in which the pressing force is sustained, such as a method of pinching with a pin, is preferable.

  Hereinafter, the present invention will be described by way of examples. In each example, the thermal conductivity as an index of thermal conductivity was determined by the following method.

(Measurement of thermal conductivity)
A 1.0 cm square heat conductive sheet was sandwiched between a transistor (2SC2233) and a water-cooled copper heat sink, and current was passed through the transistor while pressing it at a pressure of 0.6 Mpa. The temperature of the transistor: T1 (° C.) and the temperature of the copper heat sink: T2 (° C.) are measured. From the measured value and applied power: W1 (W) and film thickness (mm), the thermal conductivity: X ( W / mK) was calculated.

  X = 10 × W1 / (T1-T2)

(Measurement of tack force)
The tack force as an index of tackiness was measured with the following equipment and conditions.
Equipment used: RHESCA tacking tester TAC2
Temperature: 25 ° C
Pushing speed: 120 mm / min Pulling speed: 600 mm / min Load: 50 gf
Time: 10 seconds

(Measurement of tensile strength)
The tensile strength was measured with the following apparatus and conditions using a sample sheet punched out to 1 cm × 5 cm from the obtained heat conductive sheet.
Equipment used: STROGRAPH ES made by Toyo Seiki
Temperature: 25 ° C
Tensile speed: 5 mm / min

(Measurement of Asker C hardness)
A sheet obtained by punching out a 2 cm square heat conductive sheet is laminated until the height becomes 5 mm or more, and the molded body obtained by heating is left in a 25 ° C. environment for 1 hour, and then measured with an Asker hardness meter C type.

Example 1
As graphite particles (A), flaky expanded graphite particles (manufactured by Hitachi Chemical Co., Ltd., trade name: HGF-L, mass average diameter: 450 μm), 555 g, poly (meth) acrylate polymer compound (B ′) 145 g, butyl acrylate / ethyl acrylate / acrylonitrile / acrylic acid copolymer (copolymerization mass ratio 82/10/3/5, manufactured by Nagase ChemteX, weight average molecular weight: 530,000, Tg: −39 ° C.), cured 9.7 g of neopentyl glycol diglycidyl ether (manufactured by Nagase ChemteX, EX-211) as the agent (b), and ARUFON UP-1170 (manufactured by Toagosei Co., Ltd.) as the poly (meth) acrylate polymer compound (C) Liquid, weight average molecular weight: 8000, Tg: −57 ° C. 103 g, bisphenol A bis (diphenylphos) as flame retardant Fate) (phosphate ester flame retardant, manufactured by Daihachi Chemical Industry Co., Ltd., trade name: CR-741) was premixed in a polyethylene bag to obtain a composition.

The composition was kneaded using a roll kneader (manufactured by Kansai Roll Co., Ltd., LABOLATRY MILL (8 × 20T roll)) set at a temperature of 80 ° C. to obtain a kneaded sheet.
A part of this kneaded sheet was rounded into a 1 cm diameter sphere and formed into a 0.5 mm thick sheet with a small press. This was cut into 20 sheets and laminated again and pressed in the same manner. The surface of the sheet obtained by repeating this operation one more time was analyzed by X-ray diffraction. A peak corresponding to the (110) plane of graphite could not be confirmed in the vicinity of 2θ = 77 °, and the expanded graphite powder used (HGF-L) was “the six-membered ring plane in the crystal is oriented in the plane direction of the scale. I was able to confirm.

The obtained kneaded sheet was cut into a size of about 2 to 3 mm square to form a pellet. This was extruded into a sheet having a width of 60 mm and a thickness of 1 mm at 100 ° C. using a Laboplast Mill MODEL20C200 manufactured by Toyo Seiki Seisakusho Co., Ltd. to obtain a primary sheet.
In the kneaded sheet and the primary sheet obtained above, in order to confirm that the component (B ′) and the curing agent (b) are not cured, a part of the kneaded sheet and the primary sheet (about 0.2 g) is previously added. The component (B ′) and the curing agent (b) are unreacted by cutting and putting into a sample bottle containing 10 to 50 times the amount of n-butyl acetate and shaking it to visually check that the resin is dissolved. It was confirmed that.

  In order to determine the heating conditions such that the change in elastic modulus is 15% or less, a small amount of the above primary sheet is sampled and pressed into a 0.5 mm thick sample sheet, which is punched out to 1 cm × 5 cm, and sample sheet Was cured by shaking the temperature and time (1 hour interval). As a result, the difference in elastic modulus between the cured sample sheet heated at 170 ° C. for 6 hours and the cured sample sheet heated for 5 hours after standing in an environment at a temperature of 25 ± 1 ° C. for 1 hour was a change of 3%. . Therefore, the heating (curing) condition was 170 ° C. for 6 hours.

This primary sheet is cut into a size of 4cm x 20cm with a cutter, laminated 40 sheets, lightly pressed by hand to adhere between the sheets, and further treated with a hot air dryer at 170 ° C for 6 hours with 3kg of heavy stones placed on it. And the poly (meth) acrylic acid ester polymer compound (B ′) and the curing agent (b) are reacted in the composition. To a cross-linked cured product (B) to obtain a molded product having a thickness of 4 cm.
Next, this molded body was cooled to −20 ° C. with dry ice, and then a 4 cm × 20 cm laminated cross section was superfinished on a cannula board (manufactured by Marunaka Co., Ltd., trade name: Super Mecha Projecting length: 0.19 mm)) (slice at an angle of 0 degree with respect to the normal line coming out from the primary sheet surface), and a heat conduction sheet (I 4 cm long x 20 cm wide x 0.25 mm thick) )

  The cross section of the heat conductive sheet (I) was observed using an SEM (scanning electron microscope), and the angle from the direction seen for any 50 graphite particles to the surface of the heat conductive sheet was measured. The average value was found to be 90 degrees, and it was confirmed that the surface direction of the scale of the graphite particles was oriented in the thickness direction of the heat conductive sheet.

  A heat-conductive sheet (I) punched into a 2 cm square was laminated to a height of 5 mm or more, and when measured with an Asker hardness tester C type at 25 ° C., it was a flexible rubber sheet with an Asker C hardness of 60. I was able to confirm.

  When the heat conductivity of this heat conductive sheet (I) was measured, it showed a good value of 70 W / mK. Moreover, the adhesiveness with respect to the transistor and copper heat sink of heat conductive sheet (I) was also favorable.

When the tack force of this heat conductive sheet (I) was measured, it was 25 gf and a value sufficient for temporary fixing.
When the tensile strength of this heat conductive sheet (I) was measured, it was 0.32 MPa, which was a value sufficient for handling.

  Next, in order to confirm the heat resistance of this heat conductive sheet (I), it heat-processed at 170 degreeC for 3 h using the hot air dryer. When the tack force after the heat treatment was measured, the tack force was sufficiently maintained at 22 gf. Further, it was confirmed that the change in the tensile modulus before and after the heat treatment was as small as 5% and the heat resistance was high. The results are shown in Table 1.

(Example 2)
Implementation was carried out except that 103 g of ARUFON UP-1080 (manufactured by Toagosei Co., Ltd., liquid, weight average molecular weight: 6000, Tg: −61 ° C.) was used as the poly (meth) acrylate polymer compound (C). By operating in the same manner as in Example 1, a heat conductive sheet (II) was obtained.

  Hereinafter, the properties of the heat conductive sheet (II) were obtained by operating in the same manner as in Example 1. Observe the cross section of the heat conductive sheet (II) using SEM (scanning electron microscope), measure the angle of the surface of the scale from the direction seen for any 50 graphite particles to the surface of the heat conductive sheet, The average value was found to be 88 degrees, and it was recognized that the surface direction of the scale of the graphite particles was oriented in the thickness direction of the heat conductive sheet. It was confirmed that the Asker C hardness was 62 and was a flexible rubber sheet.

  When the heat conductivity of the heat conductive sheet (II) was measured in the same manner as in Example 1, it showed a good value of 65 W / mK. Moreover, the adhesiveness with respect to the transistor and copper heat sink of heat conductive sheet (II) was also favorable.

When the tack force of this heat conductive sheet (II) was measured, it was 22 gf, which was a value sufficient for temporary fixing.
When the tensile strength of this heat conductive sheet (II) was measured, it was 0.28 MPa, which was a value sufficient for handling.

  When the tack force after heat treatment of this heat conductive sheet (II) was measured, the tack force was sufficiently maintained at 20 gf. It was also confirmed that the change in tensile modulus before and after the heat treatment was as small as 6% and the heat resistance was high. The results are shown in Table 1.

(Example 3)
As graphite particles (A), flaky expanded graphite powder (manufactured by Hitachi Chemical Co., Ltd., trade name: HGF-L, mass average diameter: 420 μm), 538 g, poly (meth) acrylate polymer compound (B ′ ) 257 g of ethyl acrylate / butyl acrylate / acrylonitrile / acrylic acid copolymer (copolymerization mass ratio 10/82/3/5, manufactured by Nagase ChemteX, weight average molecular weight: 530,000, Tg: −39 ° C.) 21 g of bisphenol F type epoxy resin (manufactured by Toto Kasei Co., Ltd., YDF-8170C) as the curing agent (b), bisphenol A bis (diphenyl phosphate) (phosphate ester flame retardant, Daihachi Chemical Industry Co., Ltd.) as the flame retardant Manufactured, trade name: CR-741) 184 g was premixed in a stainless steel bowl, and a kneaded sheet was obtained in the same manner as in Example 1 below.
In order to determine the heating conditions such that the change in elastic modulus is 15% or less, a sample sheet was prepared and cured in the same manner as in Example 1, and the heating conditions were determined at 170 ° C. for 8 hours (elastic modulus). The condition that the change is 2%).

  Thereafter, a slice sheet having a length of 4 cm, a width of 20 cm, and a thickness of 0.25 mm was obtained in the same manner as in Example 1.

ARFUFON UP-1170 (manufactured by Toagosei Co., Ltd., liquid, weight average molecular weight: 8000, Tg: -57 ° C.) is applied with a squeegee as a poly (meth) acrylate polymer compound (C) on a PET film. extended.
By attaching and detaching the slice sheet obtained here, the poly (meth) acrylate polymer compound (C) was transferred and applied to one side of the slice sheet.
The coating amount of the poly (meth) acrylic acid ester polymer compound (C) obtained from the mass difference between the sheets before and after pasting was 1.75 mg / cm ² . The sheet was placed on a hot plate at 100 ° C. with the coated surface facing upward and heat-treated for 10 minutes to perform leveling treatment of the poly (meth) acrylate polymer compound (C). This was cooled to obtain a heat conductive sheet (III).

  Thereafter, the properties of the heat conductive sheet (III) were obtained by operating in the same manner as in Example 1. The cross section of the heat conductive sheet (III) is observed using an SEM (scanning electron microscope), and the angle with respect to the surface of the heat conductive sheet in the direction of the scale from the direction seen for any 50 graphite particles is measured, The average value was found to be 88 degrees, and it was recognized that the surface direction of the scale of the graphite particles was oriented in the thickness direction of the heat conductive sheet. It was confirmed that the Asker C hardness was 65 and the rubber sheet was flexible.

  When the heat conductivity of the heat conductive sheet (III) was measured in the same manner as in Example 1, it showed a good value of 65 W / mK. Moreover, the adhesiveness with respect to the transistor of a heat conductive sheet (III) and a copper heat sink was also favorable.

  When the tack force of the heat conductive sheet (III) was measured, the surface coated with the poly (meth) acrylate polymer compound (C) showed 70 gf and a sufficient value for fixing, and the non-coated surface was 5 gf. It was slightly sticky.

  The side of the heat conductive sheet (III) punched into a 2cm square and coated with the poly (meth) acrylate polymer compound (C) on the CPU part pad of the cooling module of a notebook PC (NEC PC-GL22ESYAA type) Was attached to a notebook computer. This operation was removed again, and the mounting operation was repeated 10 times. However, the sheet was always peeled off while stuck to the cooling module side, and no residue remained on the CPU chip side where the uncoated surface hits. It was confirmed that the sheet was excellent.

  When the tensile strength of this heat conductive sheet (III) was measured, it was 0.45 MPa, which was a value sufficient for handling.

  When the tack force after heat treatment of the heat conductive sheet (III) was measured, the surface coated with the poly (meth) acrylic acid ester polymer compound (C) had a sufficient tack force of 60 gf. The non-coated surface maintained weak adhesiveness of 5 gf. It was also confirmed that the change in tensile modulus before and after the heat treatment was as small as 6% and the heat resistance was high. The results are shown in Table 1.

Example 4
Scale-like boron nitride particles (product name: PT-110, mass average diameter: 45 μm) 742 g as hexagonal boron nitride particles (A), poly (meth) acrylate polymer compound (B ′) 100 g of butyl acrylate / ethyl acrylate / acrylic acid copolymer (copolymerization mass ratio 19/76/5, manufactured by Nagase ChemteX, weight average molecular weight: 600,000, Tg: −41 ° C.), cured As the agent (b), 8.1 g of a bisphenol F type epoxy resin (manufactured by Toto Kasei Co., Ltd., YDF-8170C), and as a poly (meth) acrylate polymer compound (C), ARUFON UP-1170 (Toagosei Co., Ltd.) Co., Ltd., liquid, weight average molecular weight: 8000, Tg: −57 ° C., 54 g, bisphenol A bis (diphenyl) as flame retardant Phosphate (phosphate ester flame retardant, manufactured by Daihachi Chemical Industry Co., Ltd., trade name: CR-741) was used in the same manner as in Example 1 below, and the length was 4 cm × width 20 cm × thickness 0. A 25 mm heat conductive sheet (IV) was obtained.
In order to determine the heating conditions such that the change in elastic modulus is 15% or less, a sample sheet is prepared and cured in the same manner as in Example 1, and the heating conditions are determined at 170 ° C. for 8 hours ( Conditions under which the elastic modulus change is 3%).

  Thereafter, the properties of the heat conductive sheet (IV) were obtained by operating in the same manner as in Example 1. Observe the cross section of the heat conductive sheet (IV) using SEM (scanning electron microscope), measure the angle of the surface of the scale from the direction seen for any 50 graphite particles to the surface of the heat conductive sheet, The average value was found to be 90 degrees, and it was confirmed that the surface direction of the scale of the graphite particles was oriented in the thickness direction of the heat conductive sheet. It was confirmed that the Asker C hardness was 65 and the rubber sheet was flexible.

  When the heat conductivity of the heat conductive sheet (IV) was measured in the same manner as in Example 1, it showed a good value of 20 W / mK. Further, the adhesion of the heat conductive sheet (IV) to the transistor and the copper heat sink was also good.

When the tack force of this heat conductive sheet (IV) was measured, it was 30 gf, which was a value sufficient for temporary fixing.
When the tensile strength of this heat conductive sheet (IV) was measured, it was 0.32 MPa, which was a value sufficient for handling.

  When the tack force after heat treatment of this heat conductive sheet (IV) was measured, the tack force was sufficiently maintained at 26 gf. It was also confirmed that the change in tensile modulus before and after the heat treatment was as small as 6% and the heat resistance was high. The results are shown in Table 1.

(Comparative Example 1)
In Example 1, the poly (meth) acrylate polymer compound (C) is not blended, the amount of the poly (meth) acrylate polymer compound (B ′) is 242 g, and the curing agent (b) A heat conductive sheet (V) was obtained in the same manner except that the amount was 16.2 g.
In order to determine the heating conditions such that the change in elastic modulus is 15% or less, a sample sheet is prepared and cured in the same manner as in Example 1, and the heating conditions are determined at 170 ° C. for 6 hours ( Conditions under which the elastic modulus change is 2%).

  Thereafter, the properties of the heat conductive sheet (V) were determined in the same manner as in Example 1. Observe the cross section of the heat conductive sheet (V) using SEM (scanning electron microscope), measure the angle of the surface of the scale from the direction seen for any 50 graphite particles to the surface of the heat conductive sheet, The average value was found to be 89 degrees, and it was confirmed that the surface direction of the scale of the graphite particles was oriented in the thickness direction of the heat conductive sheet. It was confirmed that the Asker C hardness was 65 and the rubber sheet was flexible.

  When the heat conductivity of the heat conductive sheet (V) was measured in the same manner as in Example 1, it showed a good value of 66 W / mK. Moreover, the adhesiveness with respect to the transistor of a heat conductive sheet (V) and a copper heat sink was also favorable.

When the tack force of this heat conductive sheet (V) was measured, it was 10 gf, which was insufficient for temporary fixing.
When the tensile strength of this heat conductive sheet (V) was measured, it was 0.35 MPa, which was a value sufficient for handling.

  When the tack force after heat treatment of this heat conductive sheet (V) was measured, it was further insufficient as 6 gf. It was confirmed that the change in tensile modulus before and after the heat treatment was as small as 6% and the heat resistance was high. The results are shown in Table 2.

(Comparative Example 2)
In Example 1, instead of the poly (meth) acrylate polymer compound (C), an alkylphenol tackifier (Showa Polymer Co., Ltd., CKM-9273, softening point: 80 ° C. or higher) was used. Similarly, a heat conductive sheet (VI) was obtained. The alkylphenol tackifier has a phenolic hydroxyl group.

  Thereafter, the properties of the heat conductive sheet (VI) were determined by operating in the same manner as in Example 1. The cross section of the heat conductive sheet (VI) is observed using an SEM (scanning electron microscope), and the angle from the direction seen for any 50 graphite particles to the surface of the heat conductive sheet in the surface direction of the scale is measured, The average value was found to be 89 degrees, and it was confirmed that the surface direction of the scale of the graphite particles was oriented in the thickness direction of the heat conductive sheet. The Asker C hardness was 70, which was a slightly hard rubber sheet.

  When the thermal conductivity of the thermal conductive sheet (VI) was measured in the same manner as in Example 1, it showed a good value of 60 W / mK. The adhesion of the heat conductive sheet (VI) to the transistor and the copper heat sink was slightly poor.

When the tack force of this heat conductive sheet (VI) was measured, it was 6 gf, which was insufficient for temporary fixing.
When the tensile strength of this heat conductive sheet (VI) was measured, it was 0.23 MPa, which was a value that was easily broken during handling.

  When the tack force after heat treatment of this heat conductive sheet (VI) was measured, the tackiness was lost as 0 gf. Note that the change in tensile elastic modulus before and after heat treatment was a little 20%, and the heat resistance was low. The results are shown in Table 2.

(Comparative Example 3)
In Example 1, instead of the poly (meth) acrylate polymer compound (C), bis (2-ethylhexyl) adipate which is a representative plasticizer (manufactured by Wako Pure Chemical Industries, Ltd., reagent grade 1, A heat conductive sheet (VII) was obtained in the same manner except that molecular weight: 370) was used.

  Thereafter, the properties of the heat conductive sheet (VII) were obtained by operating in the same manner as in Example 1. The cross section of the heat conductive sheet (VII) is observed using a SEM (scanning electron microscope), and the angle of the surface direction of the scale from the direction seen for any 50 graphite particles is measured with respect to the surface of the heat conductive sheet. The average value was found to be 90 degrees, and it was confirmed that the surface direction of the scale of the graphite particles was oriented in the thickness direction of the heat conductive sheet. The Asker C hardness was 50, which was a flexible rubber sheet.

  When the heat conductivity of the heat conductive sheet (VII) was measured in the same manner as in Example 1, it showed a good value of 70 W / mK. The adhesion of the heat conductive sheet (VII) to the transistor and the copper heat sink was good.

When the tack force of this heat conductive sheet (VII) was measured, it was 9 gf, which was insufficient for temporary fixing.
When the tensile strength of this heat conductive sheet (VII) was measured, it was 0.09 MPa, which was a value that was very easy to tear during handling.

  When the tack force after heat treatment of this heat conductive sheet (VII) was measured, the tackiness was 6 gf, which was further insufficient. The change in tensile elastic modulus before and after heat treatment was 9%, which was relatively high in heat resistance. The results are shown in Table 2.

(Comparative Example 4)
Instead of the poly (meth) acrylic acid ester polymer compound (C) applied in Example 3, acrylic rubber latex (manufactured by Yushi Kogyo Co., Ltd., AE-150GFT, weight average molecular weight: 1 million or more) is used. A heat conductive sheet (VIII) was obtained in the same manner except that. The coating amount was 1.2 mg / cm ² .

  Thereafter, the properties of the heat conductive sheet (VIII) were obtained by operating in the same manner as in Example 1. Observe the cross section of the heat conductive sheet (VIII) using SEM (scanning electron microscope), measure the angle of the surface of the scale from the direction seen for any 50 graphite particles to the surface of the heat conductive sheet, The average value was found to be 89 degrees, and it was confirmed that the surface direction of the scale of the graphite particles was oriented in the thickness direction of the heat conductive sheet. It was confirmed that the Asker C hardness was 65 and the rubber sheet was flexible.

  When the heat conductivity of the heat conductive sheet (VIII) was measured in the same manner as in Example 1, it showed a low value of 15 W / mK. Further, the adhesion of the heat conductive sheet (VIII) to the transistor and the copper heat sink was good.

  When the tack force of this heat conductive sheet (VIII) was measured, the surface coated with acrylic rubber latex showed 101 gf, which was a sufficient value for fixing, and the non-coated surface was weakly tacky, 5 gf.

  The thermal conductive sheet (VIII) was punched into a 2 cm square, and the surface side coated with acrylic rubber latex was attached to the CPU part pad of the cooling module of a notebook computer (NEC, PC-GL22ESYAA model), and attached to the notebook computer. . This operation was removed again, and the mounting operation was repeated 10 times. However, the sheet was always peeled off while stuck to the cooling module side, and no residue remained on the CPU chip side where the uncoated surface hits. It was confirmed that the sheet was excellent.

  When the tensile strength of this heat conductive sheet (VIII) was measured, it showed 0.44 MPa and a value sufficient for handling.

  When the tack force after heat treatment of the heat conductive sheet (VIII) was measured, the surface to which the acrylic rubber latex was applied was 25 gf, which was significantly lower than the initial value, but the necessary tack force was maintained. The non-coated surface maintained weak adhesiveness of 5 gf. Further, the change in tensile modulus before and after the heat treatment was as small as 6%, and it was confirmed that the heat resistance was high. The results are shown in Table 2.

(Comparative Example 5)
In Example 1, instead of the poly (meth) acrylate polymer compound (C), a heat conductive sheet (IX) was similarly used except that liquid NBR rubber (Nipol DN601, manufactured by Nippon Zeon Co., Ltd.) was used. Got. DN601 has a carboxyl group.

  Thereafter, the properties of the heat conductive sheet (IX) were obtained by operating in the same manner as in Example 1. The cross section of the thermal conductive sheet (IX) is observed using an SEM (scanning electron microscope), and the angle of the surface direction of the scale from the direction seen for any 50 graphite particles is measured with respect to the thermal conductive sheet surface, The average value was found to be 89 degrees, and it was confirmed that the surface direction of the scale of the graphite particles was oriented in the thickness direction of the heat conductive sheet. The Asker C hardness was 60, which was a flexible rubber sheet.

  When the thermal conductivity of the thermal conductive sheet (IX) was measured in the same manner as in Example 1, it showed a good value of 70 W / mK. The adhesion of the heat conductive sheet (IX) to the transistor and the copper heat sink was good.

When the tack force of this heat conductive sheet (IX) was measured, it was 32 gf, which was a value sufficient for temporary fixing.
When the tensile strength of this heat conductive sheet (IX) was measured, it was 0.31 MPa, which was a value sufficient for handling.

  When the tack force after heat treatment of this heat conductive sheet (IX) was measured, it became an insufficient tack property of 5 gf. The change in tensile modulus before and after heat treatment was as high as 30% and the heat resistance was low. The results are shown in Table 2.

(Comparative Example 6)
What was applied to the non-laminated primary sheet produced in Example 1 for 6 hours in a hot air dryer at 170 ° C. performed on the molded article laminated and molded in Example 1 was heated as it was. The conductive sheet (X) was evaluated.
Thereafter, the properties of the heat conductive sheet (X) were obtained by operating in the same manner as in Example 1. Observe the cross section of the heat conductive sheet (X) using SEM (scanning electron microscope), measure the angle of the surface direction of the scale from the direction seen for any 50 graphite particles to the surface of the heat conductive sheet, When the average value was calculated | required, it was 1 degree | times and the surface direction of the scale of graphite particle | grains was not oriented in the thickness direction of a heat conductive sheet.

  When the heat conductivity of the heat conductive sheet (X) was measured in the same manner as in Example 1, it showed a very low value of 3.0 W / mK. Moreover, the adhesiveness with respect to the transistor and copper heat sink of heat conductive sheet (X) was favorable.

When the tack force of this heat conductive sheet (X) was measured, it was 100 gf and a value sufficient for temporary fixing.
When the tensile strength of this heat conductive sheet (X) was measured, it was 0.39 MPa, which was a value sufficient for handling.

  When the tack force after heat treatment of this heat conductive sheet (X) was measured, the tack force was sufficiently maintained at 90 gf. Further, the change in tensile modulus before and after the heat treatment was as small as 6%, and the heat resistance was high. The results are shown in Table 2.

(Comparative Example 7)
Example except that 103 g of ARUFON UP-1000 (manufactured by Toagosei Co., Ltd., liquid, weight average molecular weight: 3000, Tg: −77 ° C.) was used instead of the poly (meth) acrylate polymer compound (C). In the same manner as in No. 1, a heat conductive sheet (XI) was obtained.

  Thereafter, the properties of the heat conductive sheet (XI) were determined in the same manner as in Example 1. The cross section of the heat conductive sheet (XI) is observed using an SEM (scanning electron microscope), and the angle with respect to the surface of the heat conductive sheet in the direction of the scale from the direction seen for any 50 graphite particles is measured, The average value was found to be 89 degrees, and it was confirmed that the surface direction of the scale of the graphite particles was oriented in the thickness direction of the heat conductive sheet. The Asker C hardness was 58, which was a flexible rubber sheet.

  When the heat conductivity of the heat conductive sheet (XI) was measured in the same manner as in Example 1, it showed a good value of 69 W / mK. Moreover, the adhesiveness with respect to the transistor and copper heat sink of heat conductive sheet (XI) was favorable.

When the tack force of this heat conductive sheet (XI) was measured, it was 11 gf, which was insufficient for temporary fixing.
When the tensile strength of this heat conductive sheet (XI) was measured, it was 0.18 MPa, which was insufficient for handling.

  When the tack force after heat treatment of this heat conductive sheet (XI) was measured, it was 9 gf, which was insufficient for temporary fixing. Further, the change in tensile elastic modulus before and after the heat treatment was as small as 5%, and the heat resistance was high. The results are shown in Table 2.

(Comparative Example 8)
As the poly (meth) acrylate polymer compound (C), an ethyl acrylate / butyl acrylate / hydroxyethyl methacrylate copolymer (copolymerization mass ratio 19/76/5, manufactured by Nagase ChemteX, HTR811DR, weight) Except that 103 g (average molecular weight: 420,000, Tg: −43 ° C., OH group-containing) was used, the same operation as in Example 1 was carried out to obtain a heat conductive sheet (XII).

  Thereafter, the properties of the heat conductive sheet (XII) were determined by operating in the same manner as in Example 1. The cross section of the heat conduction sheet (XII) is observed using an SEM (scanning electron microscope), and the angle of the surface direction of the scale from the direction seen with respect to any 50 graphite particles is measured with respect to the surface of the heat conduction sheet. The average value was found to be 89 degrees, and it was confirmed that the surface direction of the scale of the graphite particles was oriented in the thickness direction of the heat conductive sheet. The Asker C hardness was 70, which was a slightly hard rubber sheet.

  When the thermal conductivity of the heat conductive sheet (XII) was measured in the same manner as in Example 1, it showed a good value of 58 W / mK. Also, the adhesion of the heat conductive sheet (XII) to the transistor and the copper heat sink was a little bad.

When the tack force of this heat conductive sheet (XII) was measured, it was 9 gf, which was insufficient for temporary fixing.
When the tensile strength of this heat conductive sheet (XII) was measured, it was 0.38 MPa, which was a value sufficient for handling.

  When the tack force after heat treatment of this heat conductive sheet (XII) was measured, the tack force almost disappeared to 3 gf. The change in tensile modulus before and after the heat treatment was as large as 22% and the heat resistance was low. The results are shown in Table 2.

Claims (11)

Graphite particles or hexagonal boron nitride particles (A) having a scale shape, an elliptical shape, or a rod shape, and a hexagonal plane in the crystal oriented in the plane direction of the scale, the major axis direction of the ellipse, or the major axis direction of the rod A crosslinked cured product (B) of a poly (meth) acrylate polymer compound having a Tg of 50 ° C. or less, a weight average molecular weight of 5,000 to 100,000, and a Tg of 0 ° C. or less. A poly (meth) acrylic acid ester-based polymer compound (C) having no group, and the content of the graphite particles or hexagonal boron nitride particles (A) is 40% by mass or more and 85% by mass or less. A heat conductive sheet comprising the composition of
The heat conduction characterized in that the surface direction of the scale of the graphite particles or hexagonal boron nitride particles (A), the major axis direction of the ellipsoid or the major axis direction of the rod are oriented in the thickness direction of the heat conductive sheet. Sheet. The mass blending ratio of the poly (meth) acrylate polymer compound (B) to the poly (meth) acrylate polymer compound (C) is (B) :( C) = 5. : In the range of 5-7: 3,
The poly (meth) acrylate polymer compound (C) is present throughout the sheet material by internal addition, or the poly (meth) acrylate polymer compound (C) is 0.1 mg / heat conducting sheet according to claim 1, characterized in that it is coated or impregnated on the surface in an amount of cm ² or more 4 mg / cm ² or less. Thermally conductive sheet according to claim 1 or 2, wherein the said graphite particles (A) is expanded graphite. Claim 1 or 2 thermal conducting sheet, wherein said hexagonal boron nitride particles (A) is a scaly hexagonal boron nitride particles.   The said composition contains a phosphate ester type flame retardant (D) in 10 mass%-40 mass%, The heat conductive sheet as described in any one of Claims 1-4 characterized by the above-mentioned.   6. The poly (meth) acrylic acid ester polymer compound (C) is applied on one surface or impregnated on one surface, according to any one of claims 1 to 5. The heat conductive sheet as described. The scale direction of the graphite particles or hexagonal boron nitride particles (A) including the following steps (1a) to (4), the major axis direction of the ellipse, or the major axis direction of the rod is the thickness direction of the heat conductive sheet. The manufacturing method of the heat conductive sheet orientated.
(1a) Graphite particles or hexagonal boron nitride having a scale shape, an elliptical shape, or a rod shape, and a hexagonal plane in the crystal oriented in the plane direction of the scale, the major axis direction of the ellipse, or the major axis direction of the rod and particles (a), Tg is 50 ° C. or less of poly (meth) acrylic ester-based polymer compound and (B '), a curing agent Ru is crosslinked and cured to as (b), the weight average molecular weight of 5,000 to 100,000 And a poly (meth) acrylic acid ester polymer compound (C) having a Tg of 0 ° C. or less and having no reactive functional group, and the graphite particles or hexagonal boron nitride particles ( A composition having a content of A) of 40% by mass or more and 85% by mass or less is rolled, press-molded to a thickness of 20 times or less the mass average diameter of the graphite particles or hexagonal boron nitride particles (A), Extruded or coated, almost parallel with respect to the main surface Producing a primary sheet in which graphite particles or hexagonal boron nitride particles (A) are oriented in any direction,
( 2a ) A step of obtaining a molded body by laminating the primary sheet,
(3) heating the molded body to react the poly (meth) acrylate polymer compound (B ′) with the curing agent (b);
(4) A step of obtaining a sheet by slicing at an angle of 0 to 30 degrees with respect to a normal line emerging from the primary sheet surface.   The scale direction of the graphite particles or hexagonal boron nitride particles (A) including the following steps (1a) to (4), the major axis direction of the ellipse, or the major axis direction of the rod is the thickness direction of the heat conductive sheet. The manufacturing method of the heat conductive sheet orientated.
(1a) Graphite particles or hexagonal boron nitride having a scale shape, an elliptical shape, or a rod shape, and a hexagonal plane in the crystal oriented in the plane direction of the scale, the major axis direction of the ellipse, or the major axis direction of the rod Particle (A), poly (meth) acrylate polymer compound (B ′) having a Tg of 50 ° C. or less, a curing agent (b) for crosslinking and curing the same, and a weight average molecular weight of 5,000 to 100,000 And a poly (meth) acrylate polymer compound (C) having a Tg of 0 ° C. or less and having no reactive functional group, and the graphite particles or hexagonal boron nitride particles (A ) In a thickness of 20 times or less the mass average diameter of the graphite particles or hexagonal boron nitride particles (A). Molded or coated, with the main surface almost flat Process direction graphite particles or hexagonal boron nitride particles (A) to produce a primary sheet oriented such,
(2b) winding the primary sheet around the orientation direction of the graphite particles or hexagonal boron nitride particles (A) to obtain a molded body;
(3) heating the molded body to react the poly (meth) acrylate polymer compound (B ′) with the curing agent (b);
(4) A step of obtaining a sheet by slicing at an angle of 0 to 30 degrees with respect to a normal line emerging from the primary sheet surface. The scale direction of the graphite particles or hexagonal boron nitride particles (A) including the following steps (1b) to (5), the major axis direction of the ellipse or the major axis direction of the rod is the thickness direction of the heat conductive sheet. The manufacturing method of the heat conductive sheet orientated.
(1b) Graphite particles or hexagonal boron nitride having a scale shape, an elliptical shape, or a rod shape, and a hexagonal plane in the crystal oriented in the plane direction of the scale, the major axis direction of the ellipse, or the major axis direction of the rod A composition containing particles (A), a poly (meth) acrylate polymer compound (B ′) having a Tg of 50 ° C. or less, and a curing agent (b) for crosslinking and curing the composition, Rolled, pressed, extruded or coated to a thickness of 20 times or less the mass average diameter of the graphite particles or hexagonal boron nitride particles (A), and the graphite particles or hexagonal nitriding in a parallel direction with respect to the main surface Producing a primary sheet in which the boron particles (A) are oriented;
( 2a ) A step of obtaining a molded body by laminating the primary sheet,
(3) heating the molded body to react the poly (meth) acrylate polymer compound (B ′) with the curing agent (b);
(4) A step of obtaining a sheet by slicing at an angle of 0 to 30 degrees with respect to a normal line emerging from the primary sheet surface;
(5) On at least one surface of the sheet, a poly (meth) acrylate polymer compound (C) having a weight average molecular weight of 5,000 to 100,000 and a Tg of 0 ° C. or less and having no reactive functional group. ) Is applied or impregnated.   The scale direction of the graphite particles or hexagonal boron nitride particles (A) including the following steps (1b) to (5), the major axis direction of the ellipse or the major axis direction of the rod is the thickness direction of the heat conductive sheet. The manufacturing method of the heat conductive sheet orientated.
(1b) Graphite particles or hexagonal boron nitride having a scale shape, an elliptical shape, or a rod shape, and a hexagonal plane in the crystal oriented in the plane direction of the scale, the major axis direction of the ellipse, or the major axis direction of the rod A composition containing particles (A), a poly (meth) acrylate polymer compound (B ′) having a Tg of 50 ° C. or less, and a curing agent (b) for crosslinking and curing the composition, Rolled, pressed, extruded or coated to a thickness of 20 times or less the mass average diameter of the graphite particles or hexagonal boron nitride particles (A), and the graphite particles or hexagonal nitriding in a parallel direction with respect to the main surface Producing a primary sheet in which the boron particles (A) are oriented;
(2b) winding the primary sheet around the orientation direction of the graphite particles or hexagonal boron nitride particles (A) to obtain a molded body;
(3) heating the molded body to react the poly (meth) acrylate polymer compound (B ′) with the curing agent (b);
(4) A step of obtaining a sheet by slicing at an angle of 0 to 30 degrees with respect to a normal line emerging from the primary sheet surface;
(5) On at least one surface of the sheet, a poly (meth) acrylate polymer compound (C) having a weight average molecular weight of 5,000 to 100,000 and a Tg of 0 ° C. or less and having no reactive functional group. ) Is applied or impregnated. The heat conductive sheet according to any one of claims 1 to 6 or the heat conductive sheet obtained by the production method according to any one of claims 7 to 10 is interposed between a heating element and a heat radiator. A heat dissipation device.