JP5699556B2 - HEAT CONDUCTIVE SHEET, HEAT CONDUCTIVE SHEET MANUFACTURING METHOD, AND HEAT DISSIPATION - Google Patents

Description

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

  In recent years, the density of wiring for multilayer wiring boards and semiconductor packages and the mounting density of electronic components have increased, and the amount of heat generated from semiconductor packages has increased due to higher integration of semiconductor elements and greater unit heat generation. It is desired to perform the emission efficiently.

  2. Description of the Related Art In semiconductor packages, a heat radiating device that dissipates heat by closely adhering a heat conducting grease or a heat conducting sheet between a heat generating body and a heat radiating body such as aluminum or copper is generally used in a simple manner. Among these, since the heat conductive sheet can be handled as a solid, the workability when assembling the heat dissipation device is superior to that of the heat conductive grease.

  Moreover, when a heat conductive sheet can be adhere | attached, it becomes possible to temporarily attach a heat conductive sheet to a heat generating body or a heat radiator, and workability | operativity improves further. Examples of such a heat conductive sheet include a phase change sheet. However, when the adhesive heat transfer sheet is bonded to the object, heat and other energy must be applied. Therefore, the adhesive heat transfer sheet cannot be used for heat dissipation of a member having low heat resistance. Moreover, there is a problem of complication of the process of adding a further process.

  On the other hand, the heat-conductive sheet having adhesiveness is not limited in use because it does not require a heating step, and the workability is further improved because an additional step is not required.

  As a method for imparting adhesiveness to the heat conductive sheet, there is a method of forming an adhesive film or layer on the surface layer. As such an example, for example, in Patent Document 1, a silicone gel layer is provided on both surfaces of a thermally conductive support to enhance adhesion with a heat generator or a heat radiator. This silicone gel layer improves the adhesion of the sheet, and it can be temporarily fixed to the heating element or the radiator even in the mounting. In Patent Document 2, an acrylic pressure-sensitive adhesive or a urethane-based pressure-sensitive adhesive is provided on one side of a silicone-based heat dissipation sheet, and the heating element and the heat dissipation element are fixed. In Patent Document 3, sheet-like elastomer layers are formed on both sides of sheet-like graphite, and through-holes are provided in the sheet-like graphite to fill the elastomer, thereby improving the strength of the entire heat conductive sheet.

JP-A-9-17923 JP 2001-348542 A JP 2001-358264 A

  However, in the above-described heat conductive sheet of Patent Document 1, the silicone gel layer does not have a sufficient adhesive force, so that further improvement is made to maintain a long-term adhesive state in a heat dissipation device that generates thermal stress. Is desired. Moreover, in the heat conductive sheet of patent document 2, in order to adhere | attach a silicone type thermal radiation sheet and an adhesive layer, formation of the primer layer to an adhesive layer, direct application | coating of silicone to an adhesive layer, and subsequent heating The manufacturing process of the heat conductive sheet such as cross-linking is complicated. Moreover, since silicone is applied onto the pressure-sensitive adhesive layer, it is possible to impart adhesiveness only to one side of the heat conductive sheet. Moreover, in the heat conductive sheet of Patent Document 3, since the sheet-shaped graphite through-holes are filled with the elastomer, the interfacial peeling between the sheet-shaped elastomer layer and the sheet-shaped graphite is suppressed. The manufacturing process of a heat conductive sheet is complicated, such as immersing sheet-like graphite in a liquid elastomer for filling.

  An object of the present invention is to use a heat conductive sheet having high adhesion to a heating element and a heat radiator, having stress relaxation properties, and high heat conductivity, a method for producing the heat conductive sheet, and the heat conductive sheet. It is to provide a heat dissipation device.

The present invention is as follows.
<1> a heat conductive layer, and an adhesive layer provided on both surfaces or one surface of the surface of the heat conductive layer,
The thermal conductive layer comprises (A) a non-spherical particle having a volume resistivity of 10 ⁹ Ω · m or more and a thermal conductivity of 20 W / mK or more, and (B) a volume resistivity of 10 ⁹ Ω · m or more and 50 An organic polymer compound having a glass transition temperature (Tg) of not higher than ° C., and the long axis direction of the non-spherical particles (A) is oriented along the thickness direction of the heat conductive layer,
The adhesive layer includes the organic polymer compound (B) contained in the heat conductive layer as a main component,
The heat conductive layer further contains (C) a phosphate ester flame retardant in the range of 1 to 50% by volume,
A heat conduction sheet having an Asker C hardness of 40 or less at 70 ° C.
<2> a heat conductive layer and an adhesive layer provided on both surfaces or one surface of the surface of the heat conductive layer,
The thermal conductive layer comprises (A) a non-spherical particle having a volume resistivity of 10 ⁹ Ω · m or more and a thermal conductivity of 20 W / mK or more, and (B) a volume resistivity of 10 ⁹ Ω · m or more and 50 An organic polymer compound having a glass transition temperature (Tg) of not higher than ° C., and the long axis direction of the non-spherical particles (A) is oriented along the thickness direction of the heat conductive layer,
The adhesive layer includes the organic polymer compound (B) contained in the heat conductive layer as a main component,
An Asker C hardness at 70 ° C. is a heat conductive sheet of 40 or less,
(A) (A) non-spherical particles having a volume resistivity of 10 ⁹ Ω · m or more and a thermal conductivity of 20 W / mK or more; and (B) a volume resistivity of 10 ⁹ Ω · m or more and 50 ° C. or less. Kneading a composition comprising an organic polymer compound having a glass transition temperature (Tg),
(B) applying a pressure to the composition to produce a primary sheet in which the major axis direction of the non-spherical particles is oriented in a direction substantially parallel to the main surface;
(C) A step of laminating or winding the primary sheet to produce a molded body,
(D) slicing the molded body at an angle of 90 to 60 degrees with respect to the major axis direction of the non-spherical particles contained in the molded body to produce a secondary sheet; and
(E) forming a pressure-sensitive adhesive layer containing the organic polymer compound (B) on both sides or one side of the secondary sheet;
Heat conductive sheet formed through the process.
<3> a heat conductive layer, and an adhesive layer provided on both surfaces or one surface of the surface of the heat conductive layer,
The thermal conductive layer comprises (A) a non-spherical particle having a volume resistivity of 10 ⁹ Ω · m or more and a thermal conductivity of 20 W / mK or more, and (B) a volume resistivity of 10 ⁹ Ω · m or more and 50 An organic polymer compound having a glass transition temperature (Tg) of not higher than ° C., and the long axis direction of the non-spherical particles (A) is oriented along the thickness direction of the heat conductive layer,
The adhesive layer includes the organic polymer compound (B) contained in the heat conductive layer as a main component,
The organic polymer compound (B) is mainly composed of a poly (meth) acrylate polymer compound, a polymer compound having a polyisoprene structure as a main structure, a polymer compound containing chloroprene as a main raw material component, or a polybutadiene structure. Including a polymer compound having a structure;
A heat conductive sheet having an Asker C hardness of 40 or less at 70 ° C.

< 4 > The heat conductive sheet according to any one of <1> to <3>, wherein the non-spherical particles (A) include at least one of boron nitride particles and alumina particles.

< 5 > The heat conductive sheet according to any one of <1> to < 4 > , wherein the pressure-sensitive adhesive layer has a thickness of 0.1 μm to 25 μm.

< 6 > The heat conductive sheet according to any one of <1> to < 5 >, wherein the organic polymer compound (B) includes a poly (meth) acrylate polymer compound.

< 7 > The heat conductive sheet according to any one of <1> to < 6 >, wherein the thickness of the heat conductive layer is 20 times or less the major axis of the non-spherical particles (A).

< 8 > The heat conductive sheet according to any one of <1> to < 7 >, wherein the thermal conductivity is 0.5 W / mK or more.

< 9 > The heat conductive sheet according to any one of <1> to < 8 >, wherein a peel strength of an outer surface of the adhesive layer is 0.5 N / 25 mm or more.

<10> A heating element,
A radiator,
Between the said heat generating body and the said heat radiator, the heat conductive sheet of any one of said <1>-<9> arrange | positioned so that both this heat generating body and a heat radiator may be contacted,
A heat dissipation device.

<11> (A) (A) Non-spherical particles having a volume resistivity of 10 ⁹ Ω · m or more and a thermal conductivity of 20 W / mK or more, and (B) a volume resistivity of 10 ⁹ Ω · m or more and 50 A step of kneading a composition comprising an organic polymer compound having a glass transition temperature (Tg) of not higher than ° C.,
(B) applying a pressure to the composition to produce a primary sheet in which the major axis direction of the non-spherical particles is oriented in a direction substantially parallel to the main surface;
(C) A step of laminating or winding the primary sheet to produce a molded body,
(D) slicing the shaped body at an angle of 90 to 60 degrees with respect to the major axis direction of the non-spherical particles contained in the shaped body to produce a secondary sheet; and Forming a pressure-sensitive adhesive layer containing the organic polymer compound (B) on both sides or one side of the next sheet;
The manufacturing method of the heat conductive sheet of any one of said <1>-<9> containing.

<12> The step (d) is performed in a temperature range from a temperature 40 ° C. lower than the glass transition temperature of the organic polymer compound (B) to a temperature 30 ° C. higher than the glass transition temperature. The manufacturing method of the heat conductive sheet as described in 11>.

<13> The method for producing a heat conductive sheet according to <11> or <12>, wherein the step (e) is a step of transferring the adhesive layer formed on the support base material to a secondary sheet.

  ADVANTAGE OF THE INVENTION According to this invention, it has the adhesiveness which makes a mounting process easy, has high adhesiveness to a heat generating body or a heat radiator, has a stress relaxation property, and provides a heat conductive sheet with high heat conductivity.

The cross-section in an example of the heat conductive sheet of this invention is shown.

<Heat conduction sheet>
This invention has a heat conductive layer and the adhesion layer provided in the both surfaces or single side | surface of the surface of the said heat conductive layer. The thermal conductive layer comprises (A) non-spherical particles having a volume resistivity of 10 ⁹ Ω · m or more and a thermal conductivity of 20 W / mK or more, and (B) a volume resistivity of 10 ⁹ Ω · m or more. And an organic polymer compound having a glass transition temperature (Tg) of 50 ° C. or lower. The major axis direction of the non-spherical particles (A) is oriented along the thickness direction of the heat conductive layer. The said adhesion layer contains the said (B) organic polymer compound contained in the said heat conductive layer as a main component. And Asker C hardness in 70 degreeC is 40 or less.

  In the heat conductive sheet of the present invention, the organic polymer compound contained in the adhesive layer formed on the surface of the heat conductive layer and the organic polymer compound contained in the heat conductive layer are the same organic polymer compound. It is formed. For example, when the organic polymer compound contained in the heat conductive layer is a poly (meth) acrylate compound, the organic polymer compound contained in the adhesive layer is also a poly (meth) acrylate compound. For this reason, the compatibility between the organic polymer compounds is relatively high, and the adhesive layer and the heat conductive layer show a high adhesive force only by bonding without requiring a special bonding step. Thereby, it has high adhesive force which can reduce the number of fixing members in a mounting process.

Moreover, since the major axis direction of the non-spherical particles (A) having a thermal conductivity of 20 W / mK or more is oriented in the thickness direction of the thermal conductive sheet, the thermal conductive sheet of the present invention is oriented in the film thickness direction. High thermal conductivity is achieved. Furthermore, since the non-spherical particles (A) have a volume resistivity of 10 ⁹ Ω · m or more, the heat conductive sheet containing the non-spherical particles (A) has non-conductivity.

  Furthermore, since the Asker C hardness of the sheet at 70 ° C. is 40 or less, the heat conductive sheet of the present invention is sufficiently adhered to a heating element such as a semiconductor package or a display as a heat source. As a result, heat transfer to the radiator is improved.

In FIG. 1, the cross-sectional structure in an example of the heat conductive sheet of this invention is shown.
The heat conductive sheet of the present invention has a heat conductive layer 10 and an adhesive layer 20 provided on both surfaces or one surface of the surface of the heat conductive layer 10. The thermal conductive layer 10 includes (A) non-spherical particles 12 having a volume resistivity of 10 ⁹ Ω · m or more and a thermal conductivity of 20 W / mK or more, and (B) a volume resistivity of 10 ⁹ Ω · m or more and And an organic polymer compound 14 having a glass transition temperature (Tg) of 50 ° C. or lower. And the adhesion layer 20 is comprised by using the above-mentioned organic polymer compound 14 contained in the heat conductive layer 10 as a main component.

The non-spherical particles 12 are oriented so that their major axes are along the thickness direction of the heat conductive layer 10. The orientation of the non-spherical particles 12 in the heat conductive layer 10 can be observed with a SEM (scanning electron microscope) or the like in the sheet cross section. Specifically, 50 arbitrary particles are observed, and the average value of the angles with respect to the main surface of the heat conductive layer (the complementary angle is adopted when 90 ° or more) is measured. When the average value is in the range of 60 degrees to 90 degrees, it is determined that the major axis of the non-spherical particles 12 is oriented along the thickness direction of the heat conductive layer 10.
If the non-spherical particles 12 do not exhibit the above-described orientation in the heat conductive layer 10 of the present invention, sufficient heat conductivity cannot be obtained.

The non-spherical particles 12 are preferably exposed from the surface of the heat conductive layer 10.
The exposure of the non-spherical particles 12 on the surface of the heat conductive layer 10 can be evaluated by SEM observation of the surface of the heat conductive layer 10. Take a photograph of the sheet surface at a magnification that allows confirmation of at least three or more particles in the screen, and use the number of photographs that can confirm a total of 30 or more particles, and the area of the observed particles and the area of the display screen From the average value of these ratios, the exposed area ratio of the particles can be obtained.

  Furthermore, when the area of the non-spherical particles 12 exposed from the surface of the heat conductive layer 10 is 5% or more, sufficient heat conductivity is obtained, which is preferable. Moreover, when the area of the particles exposed on the sheet surface is 60% or less, the sheet tends to be excellent in flexibility and adhesion. From the viewpoint of achieving both heat conductivity and flexibility or adhesion, the area of the particles exposed from the surface of the heat conductive layer 10 is 10% to 50% of the surface area of the heat conductive layer 10. Is more preferable, and it is still more preferable that it is 20 to 40%.

  The thickness of the heat conductive layer 10 is preferably 20 times or less the major axis of the non-spherical particles 12, more preferably 1 to 20 times, and even more preferably 3 to 15 times. With respect to the major axis of the non-spherical particles 12. When the thickness of the heat conductive layer 10 is within 20 times, the heat conductivity is excellent.

  Specifically, the thickness of the heat conductive layer 10 is preferably 0.05 mm or more and 5 mm or less, more preferably 0.08 mm or more and 3 mm or less, and more preferably 0.1 mm or more and 2 mm or less. . When the thickness of the base sheet is within the above range, the handleability and heat transfer characteristics are excellent.

  In addition, the thickness of the heat conductive layer in the heat conductive sheet of this invention is measured with a thickness gauge, and it is set as the average value (average value of measurement at arbitrary five points in the same heat conductive layer). Examples of the thickness gauge include a digital dial gauge (manufactured by Mitutoyo Corporation, Digimatic Indicator ID-C112C).

  In the heat conductive sheet of the present invention, the adhesive layer 20 is provided on both surfaces or one surface of the surface of the heat conductive layer 10. The organic polymer compound 14 mainly contained in the adhesive layer 20 is the same type as the organic polymer compound 14 contained in the heat conductive layer 10.

The adhesive strength of the heat conductive sheet of the present invention is high in wettability to the adherend by the adhesive layer 20, high interaction force at the interface between the adhesive layer 20 and the adherend, and heat conduction. This is because the viscoelastic effect is obtained by the flexibility and appropriate thickness of the layer 10.
In particular, the higher the compatibility between the organic polymer compound 14 used in the adhesive layer 20 and the organic polymer compound 14 used in the heat conductive layer 10, the easier the adhesive layer 20 and the heat conductive layer 10 become integrated, and The adhesive force at the interface with the conductive layer 10 is easily improved. As a result, interface destruction between the adhesive layer 20 and the heat conductive layer 10 is unlikely to occur, and the adhesive force of the entire heat conductive sheet tends to be improved.

  When the adhesive strength of the heat conductive sheet is expressed as peel strength, the peel strength is preferably 0.5 N / 25 mm or more, more preferably 0.8 N / 25 mm or more, further preferably 1 N / 25 mm or more, and 1.5 N / 25 mm or more. Further preferred. When the peel strength is within the above range, the adhesive strength is sufficient to temporarily fix the heat conductive sheet. In addition, the peeling strength in this invention says the value measured by the method as described in the below-mentioned Example.

  The reason why the thermal conductivity of the thermal conductive sheet of the present invention is high is that the thermal conductivity of the thermal conductive layer 10 is high. As described above, the heat conductive layer 10 according to the present invention includes the non-spherical particles 12 having a thermal conductivity of 20 W / mK or more, and the long axis of the non-spherical particles 12 is in the thickness direction of the heat conductive layer 10. Since it is oriented, it exhibits high thermal conductivity. Furthermore, when the non-spherical particles 12 are exposed from the surface of the heat conductive layer 10, higher heat conductivity is exhibited.

In order to take advantage of the high thermal conductivity of the heat conductive layer 10, it is preferable to adjust the thickness of the adhesive layer 20. When the adhesive layer 20 is too thin, the adhesive force of the heat conductive sheet is reduced, and when the adhesive layer 20 is too thick, the thermal conductivity tends to be reduced.
Therefore, the thickness of the adhesive layer 20 is preferably 0.1 μm to 25 μm, more preferably 0.3 μm to 10 μm, and even more preferably 0.5 μm to 8 μm.

  The thickness of the pressure-sensitive adhesive layer 20 in the heat conductive sheet of the present invention is measured by an optical film thickness measuring device (for example, F20, manufactured by Filmetrics), and the average value (any five points in the same pressure-sensitive adhesive layer 20). Average value of measurement in

  The thermal conductivity of the heat conductive sheet is preferably 0.5 W / mK or more, more preferably 1 W / mK or more, further preferably 1.5 W / mK or more, and further preferably 2 W / mK or more. The thermal conductivity of the heat conductive sheet is determined by a laser flash method. A detailed measuring method is based on the below-mentioned Example.

  The heat conductive sheet of the present invention has an Asker C hardness of 40 or less at 70 ° C. When the Asker C hardness of the sheet at 70 ° C. exceeds 40, the sheet tends to be unable to sufficiently adhere to a heating element such as a semiconductor package or a display serving as a heat source. As a result, not only is the heat transfer to the heat radiating body inhibited, but there is a high possibility that the thermal stress will be insufficiently relaxed. The Asker C hardness of the heat conductive sheet at 70 ° C. is preferably 40 or less, and more preferably 36 or less.

  In the present invention, the “Asker C hardness of a sheet at 70 ° C.” is a molding measured by a surface thermometer after placing a molded body obtained by laminating sheets so as to have a thickness of 5 mm or more on a hot plate. It is a value measured by an Asker hardness meter C type when heated so that the body temperature becomes 70 ° C.

Moreover, since the heat conductive sheet of this invention has the adhesion layer 20, it is preferable to protect the adhesive surface of the adhesion layer 20 with a protective sheet etc. prior to use of a heat conductive sheet.
Below, the material which can be used for every member which comprises a heat conductive sheet is demonstrated.

(1) Thermal conductive layer 10
[(A) Non-spherical particles]
The non-spherical particles 12 contained in the heat conductive sheet of the present invention have a volume resistivity of 10 ⁹ Ω · m or more and a heat conductivity of 20 W / mK or more.

  The thermal conductivity of the non-spherical particles 12 is preferably 20 W / mK or more, more preferably 30 W / mK or more, and 40 W / mK or more from the viewpoint of increasing the thermal conductivity of the heat conduction layer 10. More preferably.

  The non-spherical particles 12 have a shape advantageous for non-spherical orientation, for example, a scale shape, a plate shape, an oval shape, or a rod shape. Here, in the present invention, “scale-like” refers to a thin and flat shape like a fish scale. “Ellipsoid” indicates an ellipsoidal shape obtained by rotating an ellipse, such as a rugby ball. “Bar-shaped” refers to a long and narrow columnar shape (a ratio of the length to the diameter is large, specifically, a ratio of the length to the diameter is about 100 to 500) or a prismatic shape. Any shape is anisotropic.

Specific examples of materials used for the non-spherical particles 12 include alumina (10 ⁹ to 10 ¹² Ω · m, 21 to 40 W / mK), magnesium oxide (10 ¹² to 10 ¹³ Ω · m, 60 W / mK), beryllium oxide. (> 10 ¹⁰ Ω · m, 130 W / mK), aluminum nitride (10 ¹¹ to 10 ¹² Ω · m, 70 to 200 W / mK), boron nitride (10 ¹² to 10 ¹⁴ Ω · m, 40 to 60 W / mK) And silicon nitride (10 ¹² to 10 ¹⁴ Ω · m, 25 to 155 W / mK).

  Although not particularly limited, the present invention uses at least one kind of particles selected from the group consisting of boron nitride and alumina from the viewpoint of high water resistance and low harmfulness to the human body. Is preferred.

  Although the compounding quantity of the non-spherical particle | grains 12 is not specifically limited, The range of 30-70 volume% is preferable on the basis of the volume of the whole heat conductive layer. When the blending amount is 30% by volume or more, the thermal conductivity tends to be sufficient, and when the blending amount is 70% by volume or less, the Asker C hardness tends to decrease and the adhesion tends to improve. is there.

  In addition, let content (volume%) of the nonspherical particle | grains in this specification be the value calculated | required by following Formula.

  Content of non-spherical particles (volume%) = (Aw / Ad) / ((Aw / Ad) + (Bw / Bd) + (Cw / Cd) + (Dw / Dd) +...) × 100

Aw: mass composition of non-spherical particles (mass%)
Bw: mass composition of organic polymer compound (mass%)
Cw: mass composition (mass%) of other optional components
Ad: Specific gravity of non-spherical particles (In the present invention, Ad is calculated as 2.1 for graphite, 2.2 for boron nitride, and 1.8 for carbon fiber.)
Bd: Specific gravity of organic polymer compound Cd: Specific gravity of other optional components

[(B) Organic polymer compound]
The organic polymer compound 14 can be used without particular limitation as long as it has a volume resistivity of 10 ⁹ Ω · m or more and a glass transition temperature (Tg) of 50 ° C. or less. It is.

Specific examples of the organic polymer compound 14 include a poly (meth) acrylate polymer compound (so-called acrylic rubber,> 10 ¹³ Ω · m) containing butyl acrylate, 2-ethylhexyl acrylate, or the like as a main raw material component. ), A polymer compound having a polydimethylsiloxane structure as a main structure (so-called silicone resin, 10 ¹² to 10 ¹³ Ω · m), a polymer compound having a polyisoprene structure as a main structure (so-called isoprene rubber, natural rubber, 10 ¹³ To 10 ¹⁵ Ω · m), a polymer compound containing polychloroprene as a main raw material component (polychloroprene, so-called neoprene rubber 10 ¹⁰ to 10 ¹¹ Ω · m), a polymer compound having a polybutadiene structure as a main structure (so-called butadiene rubber) ,> ^{10 10} Ω · m) or the like, generally flexible are collectively referred to as "rubber" Yes It includes polymeric compounds.

  Among these, in particular, poly (meth) acrylic acid ester-based polymer compounds containing butyl acrylate or 2-ethylhexyl acrylate as a main raw material component are easy to obtain high flexibility, chemical stability and It is preferable because it is excellent in processability, is easy to control the tackiness, and is relatively inexpensive.

  As a poly (meth) acrylate polymer compound, a copolymer (homopolymer) of a monomer selected from butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate and the like having a Tg of −30 ° C. or less. A copolymer having a structure in which polar groups such as —COOH group, —CN group, and —OH group are introduced by copolymerizing acrylic acid, acrylonitrile, hydroxyethyl acrylate and the like is preferable.

  The glass transition temperature (Tg) of the organic polymer compound 14 is 50 ° C. or less, preferably −70 to 20 ° C., more preferably −60 to 0 ° C. When said Tg is 50 degrees C or less, it is excellent in a softness | flexibility and there exists a tendency for the adhesiveness with respect to a heat generating body and a heat radiator to improve. In the present invention, the glass transition temperature is measured using thermomechanical measurement (TMA).

Although it does not specifically limit, As a compound which can be used conveniently by this invention, for example, acrylate ester copolymer resin “HTR-280DR (trade name)” manufactured by Nagase ChemteX (butyl acrylate / acrylonitrile / acrylic acid copolymer) Polymer, Mw 900,000, Tg-30.9 ° C., volume resistivity> 10 ¹³ Ω · m).

  In addition, it is preferable to include a crosslinked structure within a range that does not impair flexibility, from the viewpoint of long-term adhesion retention and film strength. For example, a polymer having a polar group such as —OH group may include a crosslinked structure by reacting a compound having a functional group that binds to the polar group such as an isocyanate group or an epoxy group with the polar group. it can.

  Although content in particular of the organic polymer compound 14 is not restrict | limited, It is preferable that it is 10-70 volume% with respect to the volume of the whole heat conductive layer, and 20-50 volume% is more preferable.

〔Flame retardants〕
The heat conductive layer 10 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, and it is preferable to contain a phosphate ester flame retardant.

  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. In addition, it is preferable that the flame retardant is a phosphoric acid ester compound and is a liquid material having a freezing point of 15 ° C. or lower and a boiling point of 120 ° C. or higher, which makes it easy to achieve both flame retardancy and flexibility and tackiness. . Examples of liquid phosphate ester flame retardants having a freezing point of 15 ° C. or lower and a boiling point of 120 ° C. or higher include trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, cresyl-2,6 -Xylenyl phosphate, resorcinol bisdiphenyl phosphate, bisphenol A bis (diphenyl phosphate) and the like.

  The content of the flame retardant is not particularly limited, but is preferably 1 to 50% by volume, more preferably 5 to 50% by volume, and still more preferably 10 to 40% by volume with respect to the total volume of the heat conductive layer. When the content of the flame retardant is within the above range, sufficient flame retardancy is exhibited and it is advantageous in terms of flexibility. When the content of the flame retardant is 1% by volume or more, sufficient flame retardancy is easily obtained, and when it is 50% by volume or less, the sheet strength tends to be improved.

〔Additive〕
The heat conductive layer 10 further comprises a toughness improver such as urethane acrylate; a moisture absorbent such as calcium oxide or magnesium oxide; an adhesive strength improver such as a silane coupling agent, a titanium coupling agent, or an acid anhydride; Wetting improvers such as system surfactants and fluorosurfactants; antifoaming agents such as silicone oil; ion trapping agents such as inorganic ion exchangers; and the like can be appropriately added.

(2) Adhesive layer 20
The adhesive layer 20 contains an organic polymer compound 14 of the same type as the organic polymer compound 14 contained in the heat conductive layer 10 as a main component. Therefore, the organic polymer compound 14 contained in the adhesion layer 20 has a volume resistivity of 10 ⁹ Ω · m or more and a glass transition temperature (Tg) of 50 ° C. or less. Here, “as the main component” means that 50% by volume or more is contained in the adhesive layer 20, preferably 50% by volume or more, more preferably 60% by volume or more of the organic polymer compound 14, More preferably, it contains 70 volume% or more.

  If it is the same kind of organic polymer compound 14 as the organic polymer compound 14 contained in the heat conductive layer 10, the organic polymer compound 14 used for the adhesion layer 20 can be used without particular limitation. Among them, a poly (meth) acrylic acid ester-based polymer compound is preferable because it is easy to obtain high flexibility, is excellent in chemical stability and processability, is easy to control adhesiveness, and is relatively inexpensive. In the present invention, the “same kind” organic polymer compound means that the chemical structure is the same, and the molecular weight may be different. However, considering the convenience in production such as availability, it is preferable that the molecular weight is the same.

  Moreover, you may add a flame retardant and an additive to the adhesion layer 20 as needed. Examples of the flame retardant and other additives that can be added to the adhesive layer 20 include those described in the heat conductive layer 10.

When the adhesive layer 20 is produced by coating, a coating solution containing the organic polymer compound 14 in an organic solvent may be used. Such an organic solvent can be appropriately selected according to the kind of the organic polymer compound 14 such as methyl ethyl ketone, toluene, acetone, methyl isobutyl ketone, cyclohexanone, cyclohexanol, dimethylacetamide, isopropanol, methanol, and ethanol.
After forming the coating film by applying the coating liquid, it is preferable to dry and heat to remove the organic solvent.

(3) Other layers The adhesive surface of the adhesive layer 20 of the heat conductive sheet of this invention may be protected by the protective sheet.
Examples of the material of the protective sheet include resins such as polyethylene, polyester, polypropylene, polyethylene terephthalate, polyimide, polyetherimide, polyether naphthalate, and methylpentene film, coated paper, coated cloth, and metals such as aluminum.

  The protective sheet may be a single layer sheet or a multilayer sheet in which two or more sheets are laminated. In addition, as the protective sheet, a sheet having releasability that has been surface-treated with a release agent such as silicone or silica is preferably used.

<The manufacturing method of a heat conductive sheet>
The heat conductive sheet of the present invention comprises (1) a kneading step, (2) a primary sheet forming step, (3) a molded body forming step, (4) a slicing step [secondary sheet (heat conducting layer) forming step], ( 5) Manufactured by a process including a tackifying process.

(Primary sheet)
The primary sheet is produced through steps including the following (1) kneading step and (2) primary sheet forming step.

(1) Kneading step In the kneading step, a composition containing the thermally conductive non-spherical particles 12 and the organic polymer compound 14 which are scale-like, oval or rod-like is kneaded to obtain a kneaded product. A known method can be used as the kneading means, and it is preferable to use an apparatus such as a two-roller or a kneader.
The composition may be prepared by any known method as long as the predetermined non-spherical particles 12 and the predetermined organic polymer compound 14 can be uniformly mixed. Although not particularly limited, for example, the organic polymer compound 14 is previously dissolved in a solvent to form a solution, and other additives such as non-shaped particles and a flame retardant are added to the solution, followed by stirring and drying. It is possible to prepare the composition according to a method of mixing each component using a roll kneading, a kneader, a brabender, or an extruder.

(2) Primary sheet formation process In a primary sheet formation process, a primary sheet is formed by making the kneaded material obtained by kneading into a sheet form. As a method for forming a sheet, it is preferable to use at least one forming method selected from the group consisting of rolling, pressing, extrusion, and coating. In particular, the long axis of the non-spherical particles 12 can be more reliably oriented in the sheet in-plane direction by using rolling and pressing. In addition, by using rolling and pressing, pressure can be applied during sheet forming, the non-spherical particles 12 are easily brought into contact with each other, and higher thermal conductivity tends to be obtained.

  When the sheet is formed into a sheet, the temperature condition is preferably in the range of 25 to 150 ° C. because the resin becomes brittle when it is too high and does not soften when it is too low.

  The thickness of the primary sheet is preferably 0.2 to 2.0 mm. In general, the thinner the primary sheet is, the better. However, if the thickness is too thin, the number of times of lamination or winding in the next molded body forming step is undesirably increased. If it is too thick, the orientation of the non-spherical particles 12 in the form of scales, ellipsoids or rods in the primary sheet is not preferred.

(Secondary sheet)
The secondary sheet is produced through steps including the following (3) molded body forming step and (4) slicing step.

(3) Formed body forming step In the formed body forming step, the formed body is produced by laminating or winding the primary sheet.
In the laminating step, the primary sheet may be cut out and laminated to a predetermined size to obtain a molded body, or a single sheet may be laminated in a form that is folded without cutting the end thereof to obtain a molded body. In the winding step, the primary sheet is wound to obtain a molded body. The winding method is not particularly limited. The shape of the winding is not particularly limited, and may be, for example, a cylindrical shape or a rectangular tube shape.

  The shape of the molded body may be any shape as long as no inconvenience occurs when slicing the molded body at an angle of 60 to 90 degrees with respect to the laminated surface. For example, it is also possible to form a cylindrical shaped body by forming the shape of each sheet into a circular shape and laminating them, and then implement the subsequent slice by a method such as “wig removal”.

  As the pressing force at the time of lamination and the tensile force at the time of winding are increased, the adhesive force between the primary sheets in the molded body is increased. On the other hand, as the pressing force at the time of lamination and the tensile force at the time of winding are reduced, the sliced surface of the molded body can be prevented from being crushed, and as a result, the non-spherical particles 12 are sliced sheets (secondary sheets, It is possible to prevent the area exposed from the surface of the heat conductive layer) from becoming too low. Taking these points into consideration, it is desirable to adjust the pressing force during lamination and the tensile force during winding. Specifically, for example, it is preferable to stack or roll by applying a pressure of 0.05 MPa to 1 MPa.

  Normally, it is possible to obtain sufficient adhesion between the primary sheets in the molded body by adjusting the tensile force at the time of forming the molded body. However, when the adhesive strength between the primary sheets is insufficient, lamination or winding may be performed after thinly applying a solvent or an adhesive to the sheet surface.

(4) Slicing step In the slicing step, a secondary sheet (thermal conductive layer) having an arbitrary thickness is obtained by slicing at an angle of 60 to 90 degrees with respect to the laminated surface of the molded body.
The cutting tool that can be used for slicing is not particularly limited, but it is preferable to use a slicer, a canner, or the like with a sharp blade. By using a cutting tool equipped with a sharp blade, it is possible to suppress disorder of the particle orientation in the vicinity of the surface of the secondary sheet obtained after slicing and to produce a thin sheet.

  The slicing step is preferably performed in the range of a temperature (Tg + 30 ° C.) 30 ° C. higher than the glass transition temperature (Tg) of the composition constituting the sheet to a temperature 40 ° C. lower than Tg (Tg−40 ° C.). When the temperature at the time of slicing is higher than Tg + 30 ° C., not only does the molded body become soft and it becomes difficult to perform slicing, but also the orientation of particles in the sheet tends to be disturbed. On the other hand, when the temperature at the time of slicing becomes lower than Tg-40 ° C, the molded product becomes hard and brittle, and not only does the slicing become difficult, but also the sheet tends to break immediately after slicing. A more preferred temperature for slicing is in the temperature range of Tg + 25 ° C. to Tg−25 ° C.

  Slicing is performed using a slice knife. The blade cross-sectional shape of the knife is not particularly limited, and may be symmetric or asymmetric. There are two types of slicing methods: (1) a method of moving the molded body while fixing the knife, and (2) a method of moving the knife while fixing the molded body.

  For example, when the molded body is disposed so that the specific surface corresponding to the stacking direction of the primary sheets is in the horizontal direction, the slice knife is disposed substantially horizontally. Then, the slicing knife is shifted by a predetermined height so that the blade surface of the slicing knife enters the inside of the molded body from the specific surface of the molded body. In this state, slicing is performed by moving the molded body and the slice knife so as to face each other. For example, fix the slicing knife to the base, fix the slicing knife to the base so that the blade surface of the slicing knife protrudes from the slide surface of the base by a predetermined height, and slide the compact on this slide surface. By moving, slicing is performed.

  In order to suppress the variation in the film thickness of the slice sheet (secondary sheet), it is preferable that the formed body is pressed against the slide surface during slicing. Further, as the pressing force is increased, the fluid resin component oozes out from the surface of the molded body, and the adhesive strength of the secondary sheet surface increases. Further, when the pressing force is increased, the thickness of the secondary sheet is increased. Note that the thickness of the secondary sheet can also be adjusted by the amount of protrusion from the slide surface of the knife, and the thickness of the secondary sheet increases as the amount of protrusion increases. Here, if the pressing force on the formed body at the time of slicing is too large, the burden on the knife increases, and the movement of the knife in the horizontal direction becomes difficult. Therefore, the pressing force is preferably 0.05 to 2.5 MPa, and most preferably 0.2 to 0.6 MPa.

(Heat conduction sheet)
A heat conductive sheet is produced through the process including the following (5) adhesive provision process.

(5) Adhesiveness imparting step In the adhesiveness imparting step, the adhesive layer 20 containing the organic polymer compound 14 is provided on any surface of the secondary sheet that imparts adhesiveness, for example, both surfaces or one surface of the secondary sheet. It can form and can obtain a heat conductive sheet.
The method for forming the adhesive layer 20 can be formed by a known method. For example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, a reverse roll coating method, a kiss coating method, a roll using a coating solution for forming the adhesive layer 20 A brush method, a spray coating method, an air knife coating method, a wire barber coating method, a pipe doctor method, a curtain coating method, a spin coating method, a dip coating method, an alternating lamination method, and the like can be employed.

  When the adhesive layer 20 is formed by the coating method, the base material to which the adhesive layer forming coating solution is applied may be the secondary sheet or a sheet having a releasability (release sheet). Also good. When a release sheet with an adhesive layer is formed by coating an adhesive layer forming coating solution on the release sheet, the adhesive layer 20 in the release sheet with an adhesive layer is bonded to the secondary sheet, and then the release sheet. By peeling off, the adhesive layer 20 can be transferred to the secondary sheet. In particular, in this method, the secondary sheet can be prevented from being dissolved and swollen by the organic solvent in the coating liquid for forming the adhesive layer.

  In particular, the release sheet in the release sheet with an adhesive layer can be used as it is as a protective sheet.

<Heat dissipation device>
The heat dissipating device of the present invention has a structure in which the heat conductive sheet of the present invention is interposed between the heat generating body and the heat dissipating body.
The heating element to which the heat conductive sheet of the present invention is applied preferably has a surface temperature not exceeding 200 ° C. The temperature which can use the heat conductive sheet of this invention suitably is the range of -10 degreeC-120 degreeC. Examples of the heating element suitable for the heat dissipation device of the present invention include a semiconductor package, a display, an LED, and an electric lamp.

  On the other hand, the heat radiator that can be used in the heat radiating device of the present invention is not particularly limited, and may be a typical one that is applied to the heat radiating device. For example, a heat sink using aluminum or copper fins or plates, an aluminum or copper block connected to a heat pipe, an aluminum or copper block in which cooling liquid is circulated by a pump, a Peltier element, and this Examples include aluminum and copper blocks.

  The heat dissipating device of the present invention is a device in which the heat conductive sheet of the present invention is installed between the above-mentioned heat generating body and the heat dissipating body, and the respective surfaces are brought into contact with each other and fixed. The heat conductive sheet is not particularly limited as long as it can be fixed in a state where the contact surfaces are sufficiently adhered, and any method may be used. For example, it is possible to use means such as pressing by hand to make close contact, or automatically making contact using a robot or the like. Since the heat conductive sheet of this invention has adhesiveness, even if pressing force does not last, it adheres fully enough. However, a method in which the pressing force is sustained, such as a method of screwing with a spring and a method of sandwiching with a clip, is preferable in order to enhance the adhesion.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In the following Examples, “part” means “part by mass” and “%” means “% by mass” unless otherwise specified.

[Example 1]
<Kneading of composition for primary sheet>
50% by volume of a plate-like boron nitride powder (HP-1CAW, manufactured by Mizushima Alloy Iron Co., Ltd., average particle diameter 16 μm, thermal conductivity 60 W / mK, volume resistivity 10 ¹² Ω · m) as non-spherical particles, organic polymer Acrylate ester copolymer resin (HTR-280DR, manufactured by Nagase ChemteX Corporation, butyl acrylate / acrylonitrile / acrylic acid copolymer, Mw 900,000, Tg-30.9 ° C., volume resistivity> 10 ¹³ Ω · m as a compound , 15 mass% toluene solution) with a solid content of 22.3% by volume, and cresyl-di-2,6-xylenyl phosphate (PX-110, manufactured by Daihachi Chemical Co., Ltd.), which is a phosphate ester, as a flame retardant. The composition for primary sheets was obtained by blending 7% by volume.

  Subsequently, 3.5 kg of the composition for primary sheets was kneaded for 40 minutes at a temperature of 100 ° C. using a pressure kneader to obtain a kneaded product.

<Preparation of primary sheet>
The kneaded product was compressed to a thickness of several tens of mm with a hydraulic press, and further passed through a metal roll at 80 ° C. several times to cut off the end portion to produce a primary sheet of 50 mm × 200 mm × 1 mm thickness.

<Formation of molded body>
After laminating the primary sheet to obtain a molded body having a thickness of 50 mm, it was pressed with a pressure of 0.1 MPa or less by a hydraulic press.

<Slicing process>
The molded body was placed on a slicing tool in which a knife was fixed to the table and the cutting edge of the knife protruded from the slide surface of the table so that the laminated surface of the molded body was in contact with the slide surface. This was slid while pressing at 0.3 MPa to slice the molded body to obtain a secondary sheet (heat conductive layer). When slicing, the temperature of the compact was adjusted to −10 ° C., and the compact was slid at 5 cm / min. Moreover, the protrusion amount of the blade edge from the table was adjusted so that the thickness of the secondary sheet was 0.20 mm.

<Evaluation of particle exposure>
When the obtained secondary sheet was observed with an SEM, the area ratio of particles exposed from the surface of the secondary sheet was 50%.

<Formation of adhesive layer>
Acrylic ester copolymer resin (HTR-280DR, manufactured by Nagase ChemteX Corporation, butyl acrylate / acrylonitrile / acrylic acid copolymer, Mw 900,000, Tg-30.9 ° C., volume resistivity> 10 ¹³ Ω · m, 15 (Mass% toluene solution) was diluted with a mixed solvent of methyl ethyl ketone and toluene to obtain an adhesive coating solution. An adhesive coating solution release PET film (A-31, Teijin de Interview Pont film) is coated on and dried 100 ° C. 5 minutes to obtain an adhesive film to form a pressure-sensitive layer having a thickness of 1 [mu] m. The thickness of the adhesive layer was measured with an optical film thickness meter (F20, manufactured by Filmetrics).

  The pressure-sensitive adhesive film was bonded to one side of the secondary sheet with a roll laminator, and then the pressure-sensitive adhesive film was also bonded to the opposite side of the secondary sheet with a roll laminator. Pasting was performed at a roll temperature of 25 ° C., a laminating pressure of 0.3 MPa, and a laminating speed of 0.3 m / min. Thus, a heat conductive sheet having an adhesive layer on both surfaces of the secondary sheet was obtained.

<Evaluation of particle orientation>
When the obtained thermal conductive sheet was observed with an SEM, the average major axis of the particles was 25 μm, the average value of the angle of the particles with respect to the sheet surface in the major axis direction was 85 degrees, and the orientation of the particles with respect to the thickness direction of the sheet was observed. It was.

<Hardness of thermal conductive sheet>
It was 36 when the Asker C hardness in 70 degreeC of the obtained heat conductive sheet was measured by the above-mentioned method.

<Evaluation of thermal conductivity>
The thermal conductivity of the heat conductive sheet was evaluated by a laser flash method. Using a xenon flash analyzer (Nanoflash LFA447 manufactured by NETZSCH), Xe flash was irradiated to two copper plates (1 mm thick) sandwiching a heat conductive sheet at 0.6 MPa, and the time dependency of the temperature of the back copper plate was measured. The thermal conductivity of the heat conductive sheet was evaluated by analyzing the three-layer model.
Next, the thermal resistance was evaluated from a calculation formula (thermal resistance [° C. · cm ² / W] = 10 × heat conductive sheet thickness [mm] / thermal conductivity [W / mK]). Here, the thickness of the heat conductive sheet was a value obtained by subtracting the thickness of the copper plate from the thickness of the two copper plates sandwiching the heat conductive sheet at 0.6 MPa. Table 1 shows the obtained thickness and thermal conductivity.

<Evaluation of adhesive strength>
The release PET film on one surface of the heat conductive sheet is peeled to expose the adhesive layer, and the adhesive layer exposed on the surface of the PET film with an easy adhesive layer (A4100, manufactured by Toyobo Co., Ltd.) where the easy adhesive layer is not formed. The layers were bonded by a laminator at 25 ° C., 0.3 MPa, and 0.1 m / min.

  Next, the release PET film on the other surface of the heat conductive sheet is peeled to expose the adhesive layer, and exposed to the surface of the PET film with an easy adhesive layer (A4100, manufactured by Toyobo Co., Ltd.) where the easy adhesive layer is not formed. The pressure-sensitive adhesive layer was bonded with a laminator at 25 ° C., 0.3 MPa, and 0.1 m / min. Thereby, the measurement sample which pinched | interposed the outer side of the adhesion layer of both surfaces of a heat conductive sheet with PET film was obtained.

  The peel strength at the time of peeling the PET film of the obtained measurement sample was measured with a tensile tester (Tensilon Universal Tester RTA-100, manufactured by Orientec Corp.). The peeling conditions were 25 ° C., a peeling angle of 180 degrees, and a peeling speed of 0.5 m / min. The peel strength obtained is shown in Table 1.

[Example 2]
A heat conductive sheet was produced in the same manner as in Example 1, except that the thickness of the adhesive layer was changed to 3 μm. The heat conductive sheet was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[Example 3]
A heat conductive sheet was produced in the same manner as in Example 1, except that the thickness of the adhesive layer was changed to 6 μm. The heat conductive sheet was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[Example 4]
A heat conductive sheet was produced in the same manner as in Example 1, except that the thickness of the adhesive layer was changed to 25 μm. The heat conductive sheet was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[Comparative Example 1]
The following adhesive film was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

<Production of adhesive film>
Acrylic ester copolymer resin (HTR-280DR, manufactured by Nagase ChemteX Corporation, butyl acrylate / acrylonitrile / acrylic acid copolymer, Mw 900,000, Tg-30.9 ° C., volume resistivity> 10 ¹³ Ω · m, 15 (Mass% toluene solution) was diluted with a mixed solvent of methyl ethyl ketone and toluene to obtain an adhesive coating solution. The pressure-sensitive adhesive coating solution was applied to a release PET film (A-31, Teijin Dupont Film) and dried at 100 ° C. for 5 minutes to obtain a pressure-sensitive adhesive film having a pressure-sensitive adhesive layer having a thickness of 10 μm.

[Comparative Example 2]
A heat conductive sheet was produced in the same manner as in Example 1 except that the secondary sheet was not provided with an adhesive layer. The heat conductive sheet was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[Comparative Example 3]
Evaluation was performed in the same manner as in Example 1 using an adhesive heat conductive sheet (thermal conductive double-sided adhesive silicone tape, TC-10SAS, manufactured by Shin-Etsu Chemical Co., Ltd.), and the results are shown in Table 1.

As shown in the above table, the heat conductive sheets of Examples 1 to 4 are the heat conductive sheet of Comparative Example 1 consisting only of the adhesive layer, the heat conductive sheet of Comparative Example 2 having no adhesive layer, and a commercially available adhesive. It turns out that it is excellent in peel strength, without reducing heat conductivity compared with a heat conductive sheet with a silicone tape (comparative example 3).
Moreover, since the Asker C hardness is 40 or less, the heat conductive sheets of Examples 1 to 4 are excellent in thermal stress relaxation properties.

10 Thermal Conductive Layer 12 Non-spherical Particle 14 Organic Polymer Compound 20 Adhesive Layer

Claims (13)

A heat conductive layer, and an adhesive layer provided on both sides or one side of the surface of the heat conductive layer,
The thermal conductive layer comprises (A) a non-spherical particle having a volume resistivity of 10 ⁹ Ω · m or more and a thermal conductivity of 20 W / mK or more, and (B) a volume resistivity of 10 ⁹ Ω · m or more and 50 An organic polymer compound having a glass transition temperature (Tg) of not higher than ° C., and the long axis direction of the non-spherical particles (A) is oriented along the thickness direction of the heat conductive layer,
The adhesive layer includes the organic polymer compound (B) contained in the heat conductive layer as a main component,
The heat conductive layer further contains (C) a phosphate ester flame retardant in the range of 1 to 50% by volume,
A heat conduction sheet having an Asker C hardness of 40 or less at 70 ° C. A heat conductive layer, and an adhesive layer provided on both sides or one side of the surface of the heat conductive layer,
The thermal conductive layer comprises (A) a non-spherical particle having a volume resistivity of 10 ⁹ Ω · m or more and a thermal conductivity of 20 W / mK or more, and (B) a volume resistivity of 10 ⁹ Ω · m or more and 50 An organic polymer compound having a glass transition temperature (Tg) of not higher than ° C., and the long axis direction of the non-spherical particles (A) is oriented along the thickness direction of the heat conductive layer,
The adhesive layer includes the organic polymer compound (B) contained in the heat conductive layer as a main component,
An Asker C hardness at 70 ° C. is a heat conductive sheet of 40 or less ,
(A) (A) non-spherical particles having a volume resistivity of 10 ⁹ Ω · m or more and a thermal conductivity of 20 W / mK or more; and (B) a volume resistivity of 10 ⁹ Ω · m or more and 50 ° C. or less. Kneading a composition comprising an organic polymer compound having a glass transition temperature (Tg),
(B) applying a pressure to the composition to produce a primary sheet in which the major axis direction of the non-spherical particles is oriented in a direction substantially parallel to the main surface;
(C) A step of laminating or winding the primary sheet to produce a molded body,
(D) slicing the molded body at an angle of 90 to 60 degrees with respect to the major axis direction of the non-spherical particles contained in the molded body to produce a secondary sheet; and
(E) forming a pressure-sensitive adhesive layer containing the organic polymer compound (B) on both sides or one side of the secondary sheet;
Heat conductive sheet formed through the process . A heat conductive layer, and an adhesive layer provided on both sides or one side of the surface of the heat conductive layer,
The thermal conductive layer comprises (A) a non-spherical particle having a volume resistivity of 10 ⁹ Ω · m or more and a thermal conductivity of 20 W / mK or more, and (B) a volume resistivity of 10 ⁹ Ω · m or more and 50 An organic polymer compound having a glass transition temperature (Tg) of not higher than ° C., and the long axis direction of the non-spherical particles (A) is oriented along the thickness direction of the heat conductive layer,
The adhesive layer includes the organic polymer compound (B) contained in the heat conductive layer as a main component,
The organic polymer compound (B) is mainly composed of a poly (meth) acrylate polymer compound, a polymer compound having a polyisoprene structure as a main structure, a polymer compound containing chloroprene as a main raw material component, or a polybutadiene structure. Including a polymer compound having a structure;
A heat conduction sheet having an Asker C hardness of 40 or less at 70 ° C. The heat conductive sheet according to any one of claims 1 to 3, wherein the non-spherical particles (A) include at least one of boron nitride particles and alumina particles. The thickness of the adhesive layer, the thermal conductivity sheet according to any one of claims 1 to 4 is 0.1Myuemu～25myuemu. The heat conductive sheet according to any one of claims 1 to 5 , wherein the organic polymer compound (B) includes a poly (meth) acrylate polymer compound. The thickness of the said heat conductive layer is 20 times or less of the major axis of the said non-spherical particle (A), The heat conductive sheet of any one of Claims 1-6 . Thermal conductivity, thermal conductivity sheet according to any one of claims 1 to 7 is 0.5 W / mK or more. The heat conductive sheet according to any one of claims 1 to 8 , wherein a peel strength of an outer surface of the adhesive layer is 0.5 N / 25 mm or more. A heating element;
A radiator,
The heat conductive sheet according to any one of claims 1 to 9, which is disposed between the heat generating body and the heat radiating body so as to be in contact with both the heat generating body and the heat radiating body.
A heat dissipation device. (A) (A) non-spherical particles having a volume resistivity of 10 ⁹ Ω · m or more and a thermal conductivity of 20 W / mK or more; and (B) a volume resistivity of 10 ⁹ Ω · m or more and 50 ° C. or less. Kneading a composition comprising an organic polymer compound having a glass transition temperature (Tg),
(B) applying a pressure to the composition to produce a primary sheet in which the major axis direction of the non-spherical particles is oriented in a direction substantially parallel to the main surface;
(C) A step of laminating or winding the primary sheet to produce a molded body,
(D) slicing the shaped body at an angle of 90 to 60 degrees with respect to the major axis direction of the non-spherical particles contained in the shaped body to produce a secondary sheet; and Forming a pressure-sensitive adhesive layer containing the organic polymer compound (B) on both sides or one side of the next sheet;
The manufacturing method of the heat conductive sheet of any one of Claims 1-9 containing this.   The said process (d) is implemented within the temperature range from the temperature 40 degreeC lower than the glass transition temperature of the said organic polymer compound (B) to the temperature 30 degreeC higher than this glass transition temperature. Of manufacturing a heat conductive sheet.   The method for producing a heat conductive sheet according to claim 11 or 12, wherein the step (e) is a step of transferring the pressure-sensitive adhesive layer formed on the supporting base material to a secondary sheet.