KR101626237B1 - Method for manufacturing thermally conductive sheet - Google Patents

Abstract

At least a first base material-adhering film and a second base material-adhering film each having a base material and a film including thermally conductive particles and a thermosetting resin provided on the base material are prepared, and the first base material-adhered film and the second base material- The first roll and the second roll forming the pair are placed in contact with each other and placed between the pair of rolls of the first roll and the second roll, And applying a pressure to the second base material-adhering film and the first base material-adhering film and the second base material-adhering film in a superposed manner.

Description

METHOD FOR MANUFACTURING THERMALLY CONDUCTIVE SHEET [0002]

The present invention relates to a method of manufacturing a heat conductive sheet.

In electronic apparatuses such as power control devices and information communication devices, large capacity, high performance, and miniaturization are progressing, and the electronic components mounted on the electronic devices are remarkably densified. As the capacity of electronic components increases and the mounting density increases, the amount of heat generated from electronic components increases. From the viewpoints of ensuring the stability of operation of electronic devices and reducing the load on the environment, securing heat dissipation of the electronic components becomes more important have.

As a means for securing the heat radiation performance of the electronic component, a heat sink, a heat dissipation fin or the like is mainly used. Since copper, aluminum, or the like having high thermal conductivity is often used for these heat sinks, heat dissipation fins, and the like, the heat conduction sheet for joining the electronic component with the heat sink and the heat dissipation fins is required to have both the insulating property and the heat conductivity do. As the heat conduction sheet, ceramic sheets such as alumina and zirconia have been mainly used. On the other hand, recently, a thermally conductive sheet of a composite material filled with thermally conductive particles having a high thermal conductivity in an organic material such as a thermosetting resin has been attracting attention because it has both high thermal conductivity and insulating properties and also has adhesiveness.

In a thermally conductive sheet of a composite material filled with thermally conductive particles having a high thermal conductivity for an organic material, the thermal conductivity of the thermally conductive sheet changes depending on the dispersion state of the thermally conductive particles in the organic material. Further, the residual of bubbles in the sheet or the smoothness of the sheet surface affects the insulating property of the heat conductive sheet. As to the dispersion state of the thermally conductive particles, the bubble residue to the inside of the sheet, and the smoothness of the sheet surface, the material properties such as the fluidity of the organic material, the adhesiveness of the organic material and the thermally conductive particles affect the production, Methods are also important influencing factors. A process that is considered to be particularly important among the methods of manufacturing the heat conductive sheet is a process of applying pressure in the film thickness direction of the heat conductive sheet.

As a method of applying pressure in the film thickness direction, there is a manufacturing method for hot-pressing an insulating sheet obtained by molding an insulating composition containing an inorganic filler and a thermosetting resin into a sheet form (for example, Japanese Patent Laid- 130251). There is also a manufacturing method in which a resin composition having an epoxy resin, a curing agent and an inorganic filler is sandwiched between two support films and passed between upper and lower rolls of a roll press to form a sheet (for example, See JP-A-2011-90868).

However, when a batch type flat plate press is used as a hot press as in the manufacturing method disclosed in Japanese Patent Application Laid-Open No. 2009-130251, it may be difficult to uniformly apply the pressure in the press surface, May occur. If pressure unevenness occurs, it is difficult to disperse the particles filled in the organic material with good precision, and bubbles are likely to remain in the sheet. Further, it is difficult to ensure smoothness of the surface of the sheet. The sheet obtained by this method can not be said to be sufficient in terms of heat conductivity or insulation.

On the other hand, in the case of the manufacturing method disclosed in Japanese Patent Laid-Open Publication No. 2011-90868, since the resin composition is sandwiched between the support film on the upper face and the support film on the lower face, bubbles can easily be incorporated between the support films, , The entrapped bubbles tend to remain on the sheet. In addition, a penetrating pinhole is likely to occur in the thickness direction of the sheet. The sheet obtained by this method can not be said to be sufficient in terms of heat conductivity or insulating property as described above.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing a heat conductive sheet having high thermal conductivity and insulating properties in view of the problems of the prior art.

The present invention is as follows.

[1] A method for producing a laminated film, comprising the steps of: preparing at least a first base material-adhering film and a second base material-adhering film each having a film containing thermally conductive particles and a thermosetting resin provided on the base material; Placing each of the films of the adhering film in contact with each other, placing the films between a pair of rolls of a pair of first rolls and a second roll, rotating the pair of first rolls and the pair of rolls, And applying a pressure in the film thickness direction and further carrying the first base material-adhering film and the second base material-adhering film in a superimposed manner.

[2] In a cross-section formed by cutting the first roll and the second roll, the first base-attached film and the second base-attached film in a plane perpendicular to the rotation axis of the first roll and the second roll, Wherein a straight line connecting the point on the most upstream side in the rotational direction of the first roll and the center point of the first roll in a region where the first base material affixed film and the first roll contact each other is a straight line A, 2 is a straight line connecting a point on the most upstream side in the rotational direction of the second roll and a center point of the second roll in a region where the base film and the second roll come into contact with each other, At least one of the angle formed by the straight line A and the straight line C and the angle formed by the straight line B and the straight line C is not less than 30 degrees and not more than 135 degrees when the straight line connecting the center point of the first roll and the center point of the second roll is the straight line C. A method for producing a heat conductive sheet according to [1].

[3] When the mass per unit area of the film is multiplied by the mass per unit area of the film per unit area of the thermally conductive sheet whose film thickness is equal to the designed value of the film thickness, the mass per unit area of the film is expressed by the following expression 1). ≪ / RTI >

(Wherein n represents an integer of 2 or more, which represents the number of sheets of the film).

[4] Any one of [1] to [3], wherein the residual volatile matter of the film before being disposed between the first roll and the second roll is 0.3 mass% or more and 1.2 mass% or less of the total mass of the film. Wherein the heat conductive sheet is produced by a method comprising the steps of:

[5] The method for producing a thermally conductive sheet according to any one of [1] to [4], wherein the surface temperatures of the first roll and the second roll are both 60 ° C. or more and 110 ° or less.

[6] A process for producing a heat conductive sheet according to any one of [1] to [5], wherein the first base substance-adhered film and the second base substance-adhered film have a conveying speed of 0.01 m / min or more and 2 m / .

[7] The thermal conductive film according to any one of [1] to [6], wherein the linear pressure applied by the first roll and the second roll in the film thickness direction is 10 kN / m or more and 350 kN / ≪ / RTI >

[8] The method for producing a heat conductive sheet according to any one of [1] to [7], wherein the film thickness reduction rate of the heat conductive sheet represented by the following formula (2) is 50% or more and 95% or less.

[9] The method of manufacturing a laminated film according to any one of [1] to [9], wherein portions of the first base material-adhering film and the second base material-adhering film which have passed between the pair of rolls of the first roll and the second roll, The method for producing a heat conductive sheet according to any one of [1] to [8], wherein the thermally conductive sheet is disposed between rolls of a pair of rolls constituting between different rolls, and pressure is applied in the film thickness direction.

[10] The method for producing a thermally conductive sheet according to any one of [1] to [9], wherein the thermosetting resin is a liquid epoxy resin.

[11] The method for producing a thermally conductive sheet according to any one of [1] to [10], wherein the thermally conductive particles comprise a filler having at least three different volume average particle diameters.

[12] A thermally conductive sheet produced by the method for producing a thermally conductive sheet according to any one of [1] to [11].

[13] A heat conductive sheet with a metal foil provided with a metal foil on the heat conductive sheet according to [12].

[14] A semiconductor device comprising a thermally conductive sheet with a metal foil according to [13].

According to the method for producing a thermally conductive sheet of the present invention, a thermally conductive sheet having high thermal conductivity and insulating properties can be obtained.

1A is a schematic cross-sectional view showing an example of a base material-adhering film according to the present invention.
Fig. 1B is a schematic cross-sectional view showing an example of a base film-laminated film relating to the present invention.
Fig. 2 is a schematic conceptual diagram for explaining a method of arranging and pressurizing two base material-adhering films between rolls constituting a pair of rolls; Fig.
Fig. 3A is a schematic perspective view explaining a state in which two base material-adhering films are placed between two rolls and overlapped to obtain a base material-adhered film laminate; Fig.
Fig. 3B is a cross-sectional view of Fig. 3A when two base material-adhered films and two rolls are cut into a plane perpendicular to the rotation axis of the roll. Fig.
Fig. 4 is a schematic view of a production apparatus equipped with two rolls applicable to the production method related to the present invention. Fig.
Fig. 5 is a partial schematic view of a production apparatus having three rolls applicable to the production method related to the present invention. Fig.
Fig. 6 is a partial schematic view of a manufacturing apparatus having four rolls applicable to the manufacturing method according to the present invention. Fig.
Fig. 7 is a schematic view of another production apparatus having four rolls applicable to the production method related to the present invention. Fig.

A method of manufacturing a thermally conductive sheet according to the present invention is a method of manufacturing a thermally conductive sheet comprising at least a first base material-adhering film and a second base material-adhering film each having a base material and a film containing thermally conductive particles and a thermosetting resin provided on the base material, 1 base-attached film and the second base-attached film are brought into contact with each other and placed between a pair of rolls of a first roll and a second roll arranged opposite to each other, and the pair of first and second rolls A method of manufacturing a thermally conductive sheet including a plurality of bonded films, comprising rotating a roll to apply pressure in the film thickness direction of the film, and further carrying the first base-attached film and the second base- Method.

In the method of manufacturing the heat conductive sheet, by employing the above-described configuration, it is possible to suppress the expansion of the pressure distribution on the sheet surface when the first base material-adhered film and the second base material-attached film are superimposed. As a result, it is possible to suppress fluctuations in the sheet such as the thermal conductivity and the insulating property of the thermally conductive sheet including a plurality of the films combined.

Further, in the present invention, after the film of the first base material and the film of the second base material are brought into contact with each other and placed between the pair of first rolls and the second rolls, the first pair of rolls And the second roll are rotated to apply a pressure in the film thickness direction of the film. Thus, a shearing force is also applied in a direction perpendicular to the film thickness direction (in-plane direction) together with the force in the film thickness direction of each of the films. As a result, fluidity in the in-plane direction of the film occurs in the resin constituting the film. The fluidity of the film in the in-plane direction of the film causes the bubbles remaining in the resin to be discharged to the outside of the film which is on the upstream side in the rotating direction of the roll. Therefore, The amount can be reduced.

Further, since the heat conductive sheet is superimposed by bringing the films of the at least two base material-adhered films into contact with each other, it is possible to suppress the occurrence of pinholes passing through the film thickness direction after applying pressure in the film thickness direction .

Therefore, the heat conductive sheet obtained by the production method of the present invention can combine high heat conductivity and insulation.

The method for producing a thermally conductive sheet according to the present invention is preferably a method for producing a thermally conductive sheet which comprises a substrate and a film comprising a thermally conductive particle and a thermosetting resin provided on the substrate, And the first base material-adhering film and the second base material-adhering film are arranged on the upstream side in the rotational direction of the pair of rolls opposed to the first roll and the second roll, Wherein the substrate side surface of the second base film-adhering film is brought into contact with the outer circumferential surface of the second roll so as to conform to at least the center of the first roll and the center of the second roll, On the line connecting the shafts, the first base film and the second base film are placed in contact with the respective films in the pair of rolls, and the pair of rolls are rotated, Apply pressure to the film thickness direction of flow, and can also be a first substrate attached to the film and a second method of manufacturing a thermally conductive sheet containing, coupling a plurality of films, which comprises carrying superposing a base material attached to the film.

As a result, a heat conductive sheet having high thermal conductivity and insulating properties can be obtained more reliably.

When the first base material-adhered film and the second base material-attached film of the present invention are placed between the rolls of the first roll and the second roll by bringing the respective films into contact with each other, the first base material- The base material-adhered film may have a portion which does not come into contact with the circumferential surface of the first roll or the second roll, so long as the effect of the invention is not impaired. Examples of the portion that does not contact the peripheral surface of the first roll or the second roll include the first base-attached film, the second base-attached film, or both widthwise ends thereof. When the first base material-adhering film and the second base material-adhering film of the present invention are placed between the rolls of the first roll and the second roll in contact with the respective films, the first base material- The substrate-attached film is preferably sandwiched between the first roll and the second roll such that the entire area in the width direction is opposed to the circumferential surface of the first roll or the second roll.

The term " film " in the present invention means a portion formed by a material capable of forming a film out of a composite member obtained by applying a film-forming material onto a substrate.

Another aspect of the method for manufacturing a thermally conductive sheet in the present invention is a method for manufacturing a thermally conductive sheet which comprises preparing at least a first base material-adhering film and a second base material-adhering film having a base material and a film containing thermally conductive particles and a thermosetting resin provided on the base material , The film of each of the first base material-adhered film and the second base material-adhered film is brought into contact with each other, the first roll and the second roll are sandwiched by a pair of opposing rolls, and the pair of rolls are rotated, A method of producing a thermally conductive sheet in which a plurality of films are laminated including a step of applying a pressure in the film thickness direction and a step of superimposing and transporting the first base material-adhering film and the second base material-adhering film.

In the present invention, the term " process " is included in this term as long as the intended purpose of the present process is achieved, even if it can not be clearly distinguished from other processes as well as independent processes.

In the present invention, the numerical range indicated by using " ~ " represents a range including the numerical values before and after "~" as the minimum value and the maximum value, respectively.

In the present invention, the amount of each component in the composition refers to the total amount of the plurality of substances present in the composition, unless otherwise specified, when a plurality of substances corresponding to each component are present in the composition.

Hereinafter, the present invention will be described.

≪ Method of producing heat conductive sheet >

A method of manufacturing a thermally conductive sheet according to the present invention comprises preparing a first base material-adhering film and a second base material-adhering film having a base material and a film comprising thermally conductive particles and a thermosetting resin provided on the base material, The first base film and the second base film are brought into contact with each other and placed between a pair of first rolls and a second roll arranged opposite to each other, and the pair of first rolls and second rolls are rotated Adding a pressure in the film thickness direction of the film, and transporting the first base-attached film and the second base-attached film in a superimposed manner, and includes other steps as necessary.

In the present invention, the thermally conductive sheet includes a plurality of bonded films. Means that a plurality of films are bonded together in the film thickness direction of the film to form a thermally conductive sheet, and in addition to the case where the interfaces of the films are present, in addition to the case where the interfaces are lost and integrated .

The number of the films constituting the heat conductive sheet is not particularly limited and may be a film obtained by superimposing three or more films. In the case of producing a thermally conductive sheet using three or more films, the two base film-attached films are superimposed, then one of the base materials is peeled off, and the film is superimposed on the film exposed on the surface By repeating the step of superimposing the base material-adhering film, a thermally conductive sheet containing three or more films can be obtained. Hereinafter, a thermally conductive sheet including two films will be described as an example, unless otherwise specified.

The heat conduction sheet may include constituent elements other than the above-mentioned film depending on the use form, the handling and the like. Other constituent elements include a substrate, a protective film, a metal foil, and the like, and these constituent elements can be disposed on one surface or a part or entire surface of the other surface of the heat conductive sheet.

In this specification, the term "film laminate" means a combined body of a plurality of films existing in a laminate obtained by superimposing a film on which a plurality of base-adhered films or substrates and a protective film are laminated. Fig. 1B shows a schematic cross-sectional view of the substrate laminated film 5 including the film laminate 4. Fig. However, the film is called a " laminate ", but the film laminate includes not only the case where the interface between the films exists, but also the case where the interface disappears and is integrated.

(Preparation of substrate-attached film)

First, at least two substrates-adhering films are prepared. The substrate-attached film has a substrate and a film provided on the substrate. The film includes thermally conductive particles and a thermosetting resin. The base material-adhered film may be purchased as a commercially available product, or may be obtained by preparing the above film on a base material.

Fig. 1A shows a schematic cross-sectional view showing an example of the first base material-adhered film 3A. The first base material-adhered film 3A is composed of a base material 1A and a film 2A. The second substrate attachment film 3B (not shown) is also composed of the substrate 1B and the film 2B.

In the case of preparing and preparing a base material-adhered film, the production method thereof is not particularly limited as long as it can produce a film containing thermally conductive particles and a thermosetting resin, and a general manufacturing method can be applied. For example, there can be mentioned a method for producing a base material-adhering film, which comprises applying a resin composition comprising thermally conductive particles and a thermosetting resin on a substrate to form the film. The method for producing a base material-adhered film includes, for example, preparing a varnish by adding a solvent to a resin composition containing thermally conductive particles and a thermosetting resin, coating the obtained varnish on a substrate, And removing the solvent. Thus, a substrate-attached film as a state in which the film is disposed on the substrate can be produced. The respective components used for producing the thermally conductive sheet, such as the resin composition, will be described later. A method for producing the film 2A used for forming the thermally conductive sheet using the resin composition will also be described later.

It is preferable that the film (3A, 3B) is a film in which the reaction rate of the thermosetting resin constituting the film is less than 40%. The reaction rate is calculated from the calories measured by, for example, DSC (differential scanning calorimeter).

In the present invention, the two base film-attached films 3A and 3B to be prepared may be the same material or different materials. Examples of the combination of the two base film attachment films 3A and 3B having different materials include those in which the types of the base materials 1A and 1B are different from each other and those in which the surfaces of the base materials 1A and 1B facing the film have different wettabilities, The components or compositional ratios included in the films 2A and 2B are different from each other, the film thicknesses of the substrates 1A and 1B are different from each other, and the films 2A and 2B have different film thicknesses. It is preferable that the two base material-adhered films 3A and 3B each have the films 2A and 2B of the same material from the viewpoints of the thermal conductivity in the film thickness direction in the obtained heat conductive sheet and the like, It is more preferable that the film is a film (2A, 2B) having a film thickness. It is preferable that the two base material-adhered films 3A and 3B have bases 1A and 1B of the same material, respectively, and that the same material and the same material It is more preferable to have the base materials 1A and 1B of a film thickness.

In the two base material-adhered films 3A and 3B, the film thicknesses of the respective films 2A and 2B are preferably determined as follows.

In the present invention, since the thermal conductivity and the insulating property of the thermally conductive sheet vary depending on the film thickness of the thermally conductive sheet, it is preferable to determine the thickness of the thermally conductive sheet so that the thermally conductive sheet exhibits desired thermal conductivity and insulation. The film thickness of the heat conductive sheet thus determined is defined as " film thickness design value ". The mass per unit area (100 cm ² ) of the thermally conductive sheet whose film thickness is equal to the designed value of the film thickness is defined as a "mass design value". With respect to this mass design value, a product of the mass per unit area (100 cm ² ) of the film is defined as a mass multiple of the film.

It is preferable that the mass ratio of each film of the plurality of films constituting the heat conductive sheet satisfies the following formula (1). In the formula (1), n represents an integer of 2 or more, which indicates the number of films prepared for producing the thermally conductive sheet. The mass multiplication of the film may be the same or different among a plurality of films prepared for producing one thermally conductive sheet. In order to make the resulting thermally conductive sheet easily exhibit desired thermal conductivity, insulation, etc., it is preferable that a plurality of films have the same mass multiplier. On the other hand, in order to change the thermal conductivity or the like as the heat conductive sheet with respect to the film thickness direction, it is preferable that a plurality of films have different mass multipliers. The thickness of the thermally conductive sheet obtained by using a plurality of films can be set to 0.8 to 1.2 times as large as the designed value of the film thickness, and 0.8 to 1 time is preferable in that thermal conductivity can be expressed with high accuracy . The mass per unit area (100 cm ² ) of the thermally conductive sheet obtained by using a plurality of films can be 0.8 to 1.2 times as large as the mass design value, and is 0.8 to 1 time in that thermal conductivity can be expressed with high accuracy .

When the mass multiplication of the film is not less than the lower limit value of the formula (1), the insulating property of the heat conductive sheet tends to be a desired value. On the other hand, when the mass ratio of the film is not more than the upper limit value of the formula (1) The thermal conductivity of the sheet tends to be a desired value.

Specifically, when the thermally conductive sheet is formed of two films (2A, 2B), in order for the thermally conductive sheet to exhibit a desired thermal conductivity and insulation property, the mass ratio of the film is 0.3 times or more and 0.6 times or less More preferably 0.45 times or more, and more preferably 0.55 times or less. 0.3 times or more, the insulating property of the heat conductive sheet tends to be a desired value. On the other hand, when it is 0.6 or less, the thermal conductivity of the heat conductive sheet tends to be a desired value. When the heat conductive sheet is composed of three sheets of the above-mentioned films, the mass ratio of the film is preferably 0.2 times or more, more preferably 0.4 times or less, more preferably 0.3 times or more, and most preferably 0.35 times or less.

The thickness of the actual thermally conductive sheet is preferably 0.9 times or more and 1.1 times or less as much as the designed value of the film thickness in order to more stably express the desired thermal conductivity and insulation property of the thermally conductive sheet, , And more preferably 1.05 times or less. Corresponding to this, when the thermally conductive sheet is formed of two films 2A and 2B, it is preferable that the mass ratio of the film is 0.3 times or more and 0.6 times or less. When the thermally conductive sheet is formed of three or more films, the mass of the film may be a numerical value in the range expressed by the formula (1).

The average film thickness of the base material is a value obtained by dividing the average value of the average film thicknesses of the base film 3 A and 3 B in the film laminate 4 inside the substrate film laminate 5 More preferably not less than 500 탆, more preferably not less than 10 탆, and further preferably not more than 300 탆, from the viewpoint of facilitating the addition of a pressure in the film thickness direction and the like. If the thickness is not less than 5 占 퐉 or not more than 500 占 퐉, the tendency of difficulty in conveyance is easily avoided because the rigidity is too weak, and if it is not more than 500 占 퐉, the tendency that the rigidity is too strong and difficult to convey is apt to be avoided.

The average film thickness of the film and the average film thickness of the substrate are an arithmetic average of values measured at several points (for example, 10 points) on the surface of the film and substrate using a micrometer.

The remaining volatiles of the films 2A and 2B before being disposed between the rolls of the first roll and the second roll are preferably 0.3 mass% or more and 1.2 mass% or less, more preferably 0.5 mass% or more, and 1.0 And more preferably not more than 1 mass%. (5) obtained by superposing the base material-adhered films (3A, 3B) is subjected to pressure in the film thickness direction and then the base material-attached film laminate (5) There is a tendency that bendability capable of being wound on the winding core can be ensured without generating cracks in the film laminate 4 in the film laminate 4. [ On the other hand, if the residual volatile content is 1.2 mass% or less, even if the semiconductor device including the metal foil provided with the metal foil or the thermally conductive sheet with the metal foil provided with the thermally conductive sheet formed from the substrate laminated film 5 is heated, There is a tendency that swelling does not occur well. The residual volatile matter of the film is a value obtained as a mass reduction rate per unit area (for example, an area of 25 cm ² when the film is set to 5 cm x 5 cm) when the drying treatment is performed at 180 ° C for one hour under normal pressure do.

The substrate adhering films 3A and 3B to be prepared may have protective films for preventing adhesion on the surfaces of the films 3A and 3B on which the substrates 1A and 1B are not provided. In the case of preparing a substrate-adhering film having such a protective film, a protective film may be peeled off immediately before use. The protective film is not particularly limited, but the same materials as those of the base material 1A and 1B can be used.

(Pressing by a pair of rolls)

The films 2A and 2B of the substrate attachment film 3A and the substrate attachment film 3B prepared in the above are brought into contact with each other and disposed between the pair of rolls of the first roll and the second roll opposed to each other . Subsequently, the pair of rolls are rotated to apply a pressure in the film thickness direction, and further the base film (3A) and the base film (3B) are stacked and transported. As described later, from the viewpoint of reducing the surface smoothness of the films 2A and 2B and the bubbles in the films 2A and 2B, the surfaces of the first and second rolls are preferably heated . In addition, the first roll and the second roll, which are opposed to each other and form a pair, may collectively be referred to as " pair of rolls ".

Hereinafter, the manufacturing method of the present invention will be described with reference to the drawings, but the present invention is not limited thereto, for example, in which two base material-adhering films 3A and 3B are manufactured by a pair of rolls.

Fig. 2 is a schematic conceptual diagram for explaining a method of arranging two substrate adhering films 3A and 3B on a pair of rolls and pressing them. Fig. 2 shows a section perpendicular to the rotation axis of the roll, and also a section formed by cutting the roll and the two base film-attached films 3A and 3B.

As shown in Fig. 2, among the two base material-adhered films 3A and 3B, the base material-adhered film 3A is guided through the rolls while contacting the base material 1A side to the outer peripheral surface of the first roll 12A And the substrate attachment film 3B is preferably guided between the rolls while contacting the substrate 1B side to the outer peripheral surface of the second roll 12B. The film 2A of the substrate attachment film 3A and the film 2B of the substrate attachment film 3B are disposed on the side not in contact with the first roll 12A and the second roll 12B. The base film 3 A and the base film 3 B are disposed apart from each other by a distance corresponding to the diameter of the first roll 12 A and the second roll 12 B, And can be guided between rolls at a stable speed by the rotation of the second roll 12B.

When the first roll 12A and the second roll 12B are rotated in the respective rotating directions (the arrows R and R '), the straight line XX' connecting the center axes of the first and second rolls 12A and 12B, The base attachment film 3A and the base attachment film 3B are disposed between the first roll 12A and the second roll 12B. Here, the film 2A of the substrate attachment film 3A and the film 2B of the substrate attachment film 3B are overlapped and a pressure is applied to each of the films 2A and 2B in the film thickness direction .

A shearing force is applied in the in-plane direction of the film by the application of pressure in the film thickness direction to the films 2A and 2B, and fluidity is generated in the resin inside the films 2A and 2B. Thus, the bubbles inside the films 2A and 2B are pushed toward the upstream side in the rotational direction of the first roll 12A and the second roll 12B, respectively. When the films 2A and 2B are spaced apart from the upstream side in the rotating direction of the first roll 12A and the second roll 12B, the air bubbles inside the films 2A and 2B are separated from the first roll 12A, And the second roll 12B, respectively.

When the first roll 12A and the second roll 12B are rotated in a state in which the substrate affixing films 3A and 3B are disposed between the first roll 12A and the second roll 12B, Adhesive films 3A and 3B are conveyed and pass on the straight line XX '. Accordingly, substantially the same pressure is sequentially added in the film thickness direction of the films 2A and 2B. The substrate affixing films 3A and 3B are brought into close contact with each other by the pressure in the film thickness direction with respect to the films 2A and 2B to form the substrate laminate 5 with the substrate.

As described above, since the pressure is applied in the film thickness direction to the films 2A and 2B in the substrate laminated film 5 using the first roll 12A and the second roll 12B, The uniformity of the pressure distribution can be enhanced. When pressure is applied by surface contact like a flat plate press, the pressure at the periphery of the surface tends to be higher than the central portion of the surface, and it is difficult to ensure uniformity of pressure distribution within the surface. In contrast, in the method using the first roll 12A and the second roll 12B, since the pressure can be linearly concentrated by the line contact between the first roll 12A and the second roll 12B, Is considered to be linear, and the uniformity of the pressure distribution is higher than that of the flat plate press. As a result, variations in properties such as thermal conductivity and insulation properties within the plane of the heat conductive sheet are reduced as compared with the flat plate press.

Further, since the pressure is applied to the films 2A and 2B in the film thickness direction, the film laminate 4 in the base film laminate 5 is one of the causes of lowering the insulating property of the heat conductive sheet , It is possible to suppress the occurrence of through-pin holes. Here, the through pinhole means a hole of a small diameter passing through both surfaces of the heat conductive sheet.

Further, since the films 2A and 2B are superimposed and a pressure is applied in the film thickness direction, the amount of bubbles remaining in the films 2A and 2B can be reduced. Since the pressure in the film thickness direction is added by the first roll 12A and the second roll 12B which are rotating, the pressure is applied to the film laminate 4 in the base film laminate 5, Shear force is applied in a direction perpendicular to the thickness direction as well as in the thickness direction. Therefore, the flowability of the thermosetting resin in the films 2A and 2B constituting the film laminate 4 is improved, and the bubbles remaining in the resin move in accordance with the flow of the resin to form the film laminate 4 ). ≪ / RTI > As a result, the amount of air bubbles remaining in the film laminate 4 can be reduced, and in the heat conductive sheet obtained from the film laminate 4 in which the amount of air bubbles is reduced, the withstand voltage property , The insulating property is improved.

In addition, by applying pressure in the film thickness direction to the film laminate (4) in the base film laminate (5), the surface of the heat conducting sheet can be smoothened. When a pressure is applied in the film thickness direction of the film laminate 4, the thermosetting resin flows on the surface where the two films 2A and 2B in the film laminate 4 are in contact with the respective substrates 1A and 1B The surface (the surface of the heat conduction sheet) in close contact with the substrates 1A and 1B of the films 2A and 2B is smoothed since the following movements are taken on the surface of the substrate 1. [

In the case where a resin having a low thermal conductivity is present in a large amount among the thermally conductive particles as compared with the thermally conductive particles, the thermal conductivity of the thermally conductive sheet may be lowered if the distance between the thermally conductive particles is large. In this embodiment, since a pressure is applied by using a roll in the film thickness direction of the film laminate 4 immediately after the superposition, the resin existing between the thermally conductive particles is caused to flow to narrow the intervals of the particles, Can be improved.

Since the pressure is applied using the first roll 12A and the second roll 12B in the film thickness direction of the substrate laminated film 5, the steps necessary for preparing the film laminate with the protective film It can be simplified. That is, once the film 7A, 7B with the base material and the protective film attached is wound on the film drawing rolls 14A, 14B once, the film is taken out from the film drawing rolls 14A, 14B, (Refer to Fig. 4). In the case of applying a film having the same area as the substrate and the protective film attached thereto in a sheet-like manner such as a flat plate press, a process of cutting the substrate and the film having the protective film in accordance with the size of the hot plate And the step of disposing the cut out on the hot plate are required to be repeated a plurality of times, which is troublesome.

Examples of the types of the first roll 12A and the second roll 12B include rolls used in hot rolling and cold rolling of metal materials. In order to further increase the smoothness of the surface of the heat conductive sheet, rolls such as calender rolls, emboss rolls, gravure rolls, mesh rolls, and anilox rolls may be used.

The length of the first roll 12A and the second roll 12B in the axial direction is not particularly limited as long as the surface of the first roll 12A and the second roll 12B has a cylindrical or cylindrical shape with a curved surface and can be appropriately selected according to the desired size of the film .

The diameters of the first roll 12A and the second roll 12B are appropriately selected according to the desired size of the film. For example, 150 cm or more and 500 cm or less is preferable in terms of optimizing the contact time between the roll and the film, more preferably 200 cm or more and 450 cm or less. If the contact time is appropriate, for example, a desired preheating effect by the surface temperature of the first roll 12A and the second roll 12B can be obtained.

The surface temperature of the first roll 12A and the second roll 12B is preferably 60 占 폚 or higher and 110 占 폚 or lower and more preferably 70 占 폚 or higher and 100 占 폚 or lower. By setting the surface temperatures of the first roll 12A and the second roll 12B within the above range, the surface of the film 2A is easily smoothed when the thermosetting resin of the film 2A or 2B is softened to have fluidity, , 2B) is easily removed to the outside, or bubbles tend to be finely dispersed. If the surface temperature of the first roll 12A and the second roll 12B is 60 DEG C or more, the flowability of the thermosetting resin of the film 2 tends to be easily secured in a size sufficient for smoothing the film . If the surface temperature of the first roll 12A and the second roll 12B is 110 DEG C or lower, the progress of curing of the thermosetting resin can be suppressed, and as a result, the flowability of the thermosetting resin can be improved sufficiently It tends to be easy to secure in size.

When the substrate affixing films 3A and 3B are guided between the rolls of the first roll 12A and the second roll 12B, the substrate affixing film 3A is formed on the outer circumferential surface of the first roll 12A, (3B) are in contact with the outer peripheral surface of the second roll (12B). Thus, when pressure is applied in the film thickness direction of the films 2A and 2B on the straight line XX 'connecting the central axes of the first and second rolls 12A and 12B, It is possible to easily fall out to the outside. When the surface temperatures of the first roll 12A and the second roll 12B are higher than the surface temperatures of the base film-attached films 3A and 3B, the surfaces of the first roll 12A and the second roll 12B By the temperature, the substrate adhering films 3A and 3B can be heated.

The contact state between the substrate adhering film 3A and the first roll 12A and the contact state between the substrate attachment film 3B and the second roll 12B will be described with reference to Figs. 3A and 3B.

3A and 3B, the first roll 12A and the second roll 12B are separated by a plane 26 perpendicular to the rotational axes 13A and 13B of the first roll 12A and the second roll 12B, In the region where the base film 3A is in contact with the first roll 12A in the cross section (Fig. 3B) that occurs when the base film 12B and the base film attachment films 3A and 3B are cut And the straight line connecting the point P on the most upstream side in the rotational direction of the first roll 12A with the rotational axis 13A of the first roll 12A is defined as a straight line A and the straight line connecting the point P on the most upstream side in the rotational direction of the base film 3B with the second roll 12B The straight line connecting the point P 'on the most upstream side in the rotational direction of the second roll 12B in the area and the rotational axis 13B of the second roll 12B is taken as a straight line B. A straight line connecting the rotating shaft 13A of the first roll 12A and the rotating shaft 13B of the second roll 12B is a straight line C. [ The angle formed by the straight line A and the straight line C is defined as a holding angle?, And the angle formed by the straight line B and the straight line C is defined as a holding angle? '.

At least one of the holding angles? And? 'Is preferably not less than 30 占 and not more than 135 占 from the viewpoint of controlling the physical properties of the resin composition of the films 2A and 2B, Deg.] Or more and 90 [deg.] Or less.

By making the holding angles [theta] and [theta] 'equal to or greater than 30 degrees, bubbles tend to be easily released from the films 2A and 2B to the outside. Also, the time taken to preheat the surface of the first roll 12A and the second roll 12B is not too short when they are compared at the same conveying speed. Further, when a pressure is applied in the film thickness direction of the films 2A and 2B, the resin in the films 2A and 2B tends to undergo flow deformation near the portion where the pressure is concentrated. On the other hand, by setting the holding angles? And? 'To 135 ° or less, the time required for the films 2A and 2B to be preheated from the surfaces of the first roll 12A and the second roll 12B through the substrate 1, There is no case where the comparison is made at the same conveying speed. Thus, depending on the surface temperatures of the first roll 12A and the second roll 12B, there is a tendency to suppress excessive flow deformation when pressure is applied in the film thickness direction of the films 2A and 2B And also tends to be able to suppress the release of the films 2A and 2B from both side ends of the base material 1. [

The holding angles? And? 'May be the same or different. By making the holding angles [theta] and [theta] 'equal to each other, each of the two base film-attached films 3A and 3B to be prepared has the advantage of being uniformly preheated when they are made of the same material. On the other hand, by using different holding angles? And? ', There is an advantage in that, in the case where the materials of the two base film-attached films 3A and 3B to be prepared are different, they can be adjusted to receive preheating suitable for each material.

The conveying speed of the films 2A and 2B in the first roll 12A and the second roll 12B is preferably 0.01 m / min or more, more preferably 2 m / min or less, more preferably 1 m / min or less Do. When the conveying speed of the film is included in the above range, the following advantages are obtained. That is, when the surface temperatures of the first roll 12A and the second roll 12B are higher than the surface temperatures of the base film-attached films 3A and 3B, the first roll 12A and the second roll 12B When pressure is applied in the film thickness direction of the substrate laminated film 5 immediately after lamination, the film laminate 5 in the substrate laminated film 5 from the surface of the first roll 12A and the second roll 12B (See Fig. 2). As a result, the fluidity of the thermosetting resin necessary for smoothing the heat conductive sheet tends to be secured. On the other hand, the lower limit of the range of the conveying speed of the film is not particularly limited from the viewpoint of the characteristics of the thermally conductive sheet, but it is preferable that the thermally conductive sheet having a total length of 100 m is 0.07 m / min or more Do.

The linear pressure applied to the films 2A and 2B in the film thickness direction of the film stacks 4A and 4B by the first roll 12A and the second roll 12B is not less than 10 kN / m and not more than 350 kN / m or less, more preferably 20 kN / m or more and 100 kN / m or less. When the line pressure is 10 kN / m or more, a gap between the thermally conductive particles necessary for making the thermal conductivity of the thermally conductive sheet to a desired value can be secured. Thus, there is a tendency to suppress the lowering of the thermal conductivity of the heat conduction sheet. In addition, when the above line pressure is 350 kN / m or less, the film thickness of the obtained film laminate 4 becomes thin, and the film thickness of the heat conductive sheet is also not thinned. As a result, it is possible to secure a sufficient distance between the thermally conductive particles which are transferable, and the deterioration of the insulating property of the heat conductive sheet can be avoided.

The production method of the present invention is characterized in that at least two base material-adhering films are placed between rolls of a first roll and a second roll opposed to each other in contact with each other, There is no particular limitation on the constitution of the production apparatus to which the present production method is applied as far as the pressure is applied in the film thickness direction of the film and the first base substance-adhered film and the second base substance-attached film are superposed and transported.

4 is a schematic view showing an example of an apparatus for manufacturing a heat conduction sheet to which the manufacturing method of the present invention is applicable.

In the manufacturing apparatus 10 shown in Fig. 4, a first roll 12A and a second roll 12B arranged in opposition to each other, and a laminated sheet winding roll 24 are disposed. On the upstream side of the rotation direction of the first roll 12A, a film pull-out roll 14A and a protective film winding roll 16A are arranged. On the upstream side of the rotation direction of the second roll 12B, a film pull-out roll 14B and a protective film winding roll 16B are arranged. The film pulling roll 14A and the film pulling roll 14B are spaced apart from each other and the protective film winding roll 16A and the protective film winding roll 16B are spaced apart from each other.

Between the first roll 12A and the second roll 12B and the laminated sheet winding roll 24 a base winding roll 18 and a base winding roll 18 are provided from the side close to the first roll 12A and the second roll 12B And the protective film pulling roll 20 are arranged between the protective film pulling roll 20 and the laminated sheet winding roll 24. The take-up side nip rolls 22A and 22B are opposed to each other.

The manufacturing apparatus 10 is provided with a driving device (not shown) capable of controlling the rotation of the film drawing rolls 14A and 14B and the rollers 24 for winding the laminated sheet in synchronism with each other.

The rolls are rotatable from the film pulling rolls 14A and 14B to the winding roll 24 so that the films 2A and 2B, The film laminate 4 obtained by laminating and pressing them in the film thickness direction can be transported.

In the production of the heat conductive sheet, films 7A, 7B each having a rolled base material and a protective film are prepared, and each base material 1A, 1B is in contact with the first roll 12A or the second roll 12B Out rolls 14A and 14B so as to be in the direction of the film-drawing rolls 14A and 14B. The films 7A and 7B having the base material and the protective film attached thereto are pulled out as the base attachment films 3A and 3B while peeling off the protective film 6 in accordance with the rotation of the protective film winding rolls 16A and 16B, And guided between the first roll 12A and the second roll 12B, respectively.

When the films 2A and 2B in the substrate adhering films 3A and 3B are guided between the rolls, the films 2A and 2B overlap each other. A pressure is applied in the film thickness direction of the films 2A and 2B so that the film laminate 4 (see FIG. 2) (5) is obtained.

If the film 2A and the film 2B are opposed to each other when the film is guided to the first roll 12A and the second roll 12B, Which may be attached to any of the film pulling rolls 14A and 14B.

The substrate laminated film 5 having passed between the first roll 12A and the second roll 12B is placed on the downstream side in the conveying direction of the first roll 12A and the second roll 12B, The base material 1A on one side is peeled off by a peeling device and then guided to the downstream side in the carrying direction. The peeled base material 1A is wound around the base winding roll 18.

The base film laminate 5 after the substrate 1A on one side has been peeled is peeled off from the winding side nip roll 22A and the winding roll 22B on the downstream side in the rotating direction of the protective film pulling roll 20 Guidance. On the surface of the film laminate 5 from which the base material 1A is peeled and exposed, the protective film 6 drawn out from the protective film pulling-out roll 20 is laminated. The protective film 6 laminated on the film laminate 4 may be the same as or different from the protective film in the substrate 7 and the film 7 with the protective film attached thereto. Thus, the film laminate 8 to which the base material and the protective film are adhered is formed.

The film laminate 8 to which the base material and the protective film are attached is wound on the winding roll 24 with the side on which the protective film 6 is laminated inside.

The film laminate 8 with the base material and the protective film wound on the winding roll 24 can be used as the heat conductive sheet by removing the protective film 6 and the base material 1B.

In the manufacturing apparatus 10, two rolls (the first roll 12A and the second roll 12B) for obtaining the substrate-attached film laminate 5 are superimposed on the substrate-attaching films 3A and 3B, , The second roll 12B), but the number of rolls is not particularly limited as long as it is two or more. There is no particular limitation on the positions and the number of times between the rolls 2A and 2B disposed between the rolls and between rolls for applying pressure in the film thickness direction.

Another example in which the number of rolls and the position between the rolls are changed is shown in Figs. 5, 6 and 7. Fig. 5 to 7, the same members as those in Fig. 1 are denoted by the same reference numerals, and a description thereof will be omitted.

Fig. 5 shows a manufacturing apparatus 30 using three rolls.

In the manufacturing apparatus 30, the first roll 32A, the second roll 32B, and the third roll 32C (along the conveying direction of the substrate affixing films 3A and 3B and the substrate affixing film laminate 5) Are continuously arranged. The manufacturing apparatus 30 has a total of two gaps made by the second roll 32B and the third roll 32C in addition to the gap created by the first roll 32A and the second roll 32B And between the rolls. Thus, the portion of the substrate laminated film 5 disposed between the first roll 32A and the second roll 32B passes between the first roll 32A and the second roll 32B Thereafter, it is disposed between the second roll 32B and the third roll 32C, and pressure is applied in the film thickness direction. As a result, a pressure is applied to the film laminate 4 twice in the film thickness direction.

Fig. 6 shows a manufacturing apparatus 40 using four rolls.

In the manufacturing apparatus 40, the first roll 42A, the second roll 42B, the third roll 42C, and the third roll 42C are disposed along the conveying direction of the base material-adhering films 3A, 3B and the base material- And a fourth roll 42D are continuously arranged. In addition to the gap created by the first roll 42A and the second roll 42B, the gap created by the second roll 42B and the third roll 42C and the gap formed by the third roll 42C and the fourth roll 42B, And the gap formed by the roll 42D in total. Thus, the portion of the substrate laminated film 5 disposed between the first roll 42A and the second roll 42B passes through the first roll 42A and the second roll 42B , Between the second roll 42B and the third roll 42C, and between the third roll 42C and the fourth roll 42D, pressure is applied in the film thickness direction. As a result, pressure is applied to the film laminate 4 three times in the film thickness direction.

Fig. 7 also shows another manufacturing apparatus 50 using four rolls.

The manufacturing apparatus 50 is provided with a gap formed by the first roll 52A and the second roll 52B along the conveying direction of the base material affixing films 3A and 3B and the base material affixing film laminate 5 And a clearance made by the third roll 52C and the fourth roll 52D disposed at a distance from the first roll 52A and the second roll 52B. Thus, the portion of the substrate laminated film 5 disposed between the first roll 52A and the second roll 52B passes through the first roll 52A and the second roll 52B , And is disposed between the third roll 52C and the fourth roll 52D, and pressure is applied in the film thickness direction. As a result, a pressure is applied to the film laminate 4 twice in the film thickness direction.

The number of rolls which can be pressed in the film thickness direction of the film laminate 4 is not particularly limited and may be determined depending on the number of rolls in the film laminate 4, The number of pressing in the film thickness direction can be increased. The film thickness, the pillar orientation, the flatness, and the like can be adjusted by increasing the number of times the film laminate 4 is pressed in the film thickness direction.

On the other hand, the number of rolls that can be pressed in the film thickness direction of the film laminate 4 is set to two by applying pressure in the film thickness direction of the film laminate 4 at a gap formed by two rolls, Pressurization and depressurization in the film thickness direction with respect to the layered product 4, and in some cases, heating and cooling through the substrates 1A and 1B can all be terminated once. As a result, there is an advantage that the load due to the pressurization and the thermal load due to heating can be minimized to the film laminate.

Further, in the method of manufacturing a thermally conductive sheet using the manufacturing apparatuses 30, 40, and 50, the transfer speed of the film, the line pressure in the film thickness direction with respect to the film, The same conditions and preferable conditions can be adopted as they are.

In the method of manufacturing a thermally conductive sheet using the manufacturing apparatuses 10, 30, 40 and 50, the film 7 having the substrate and the protective film is used as a material, and the film laminate 8, The heat conduction sheet of the present invention is not limited thereto as long as it is manufactured by combining a plurality of films formed of a resin composition comprising thermally conductive particles and a thermosetting resin.

(Heat conductive sheet)

The thermally conductive sheet obtained by the production method of the present invention includes a plurality of bonded films.

From the viewpoints of heat resistance and insulation, the average thickness of the thermally conductive sheet is preferably 100 占 퐉 or more and 250 占 퐉 or less, more preferably 110 占 퐉 or more and 230 占 퐉 or less from the viewpoint of thermal conductivity and adhesiveness, Mu m or more, and more preferably 210 mu m or less.

The average film thickness of the heat conduction sheet is an arithmetic average of values obtained by measuring the surface of the heat conduction sheet at several points (for example, 10 points) using a micrometer.

Further, the film thickness of the heat conductive sheet may be smaller than the total film thickness of the plurality of prepared films. Preferably 75% or more and 95% or more, more preferably 50% or more and 95% or less, and more preferably 95% or more, in view of the fact that the thermal conductivity and insulating property of the heat- Or less.

Here, the film thickness of the heat conduction sheet is the average film thickness obtained by the same measurement method as the average film thickness of the above-mentioned heat conduction sheet. When the heat conductive sheet is provided with other constituent elements such as a base material and a metal foil, the average thickness after removal of other constituent elements such as the base material is used.

The total film thickness of the prepared film is the sum of the average film thickness of the film in the prepared substrate-attached film. The average film thickness of the film is the average film thickness obtained after removing the substrate from the base film.

As a method for removing a substrate or the like made of a resin or the like from a base material-adhered film, a base material-adhered film-laminate material or a base material and a film laminate adhering a protective film, there is a method of peeling off a substrate or the like using an adhesive tape or the like And the like. As a method of removing the metal foil, there is a method of removing by etching using an aqueous ammonium persulfate solution.

When the film thickness reduction rate falls within the above range, the interval between the thermally conductive particles is preferable from the viewpoint of securing the interval between the thermally conductive particles, which can improve the thermal conductivity without lowering the insulating property of the thermally conductive sheet. If the film thickness reduction ratio is 50% or more, the film thickness of the film laminate 4 in the substrate laminated film 5 obtained by adding pressure in the film thickness direction tends not to become excessively thin. As a result, since the interval between the thermally conductive particles is not excessively narrowed, deterioration of the insulating property as the obtained thermally conductive sheet can be suppressed. When the reduction rate of the film thickness is 95% or less, the film thickness of the film laminate 4 in the base film laminate 5 obtained by adding pressure in the film thickness direction is not excessively increased. As a result, since the interval between the thermally conductive particles is not excessively widened, the lowering of the thermal conductivity as the obtained thermally conductive sheet can be suppressed.

The residual volatile matter in the thermally conductive sheet is preferably 0.1 mass% or more and 0.8 mass% or less, more preferably 0.1 mass% or more and 0.5 mass% or less. When the amount is 0.1% by mass or more, the heat conductive sheet tends to have flexibility capable of being mounted on a semiconductor device or the like without generating cracks. If it is 0.8% by mass or less, it is preferable that the interfacial expansion tends not to occur even if the thermally conductive sheet with the metal foil provided with the metal foil on the heat conductive sheet and the semiconductor device including the thermally conductive sheet are heated. The residual volatile matter in the heat-conducting sheet is a mass reduction rate per unit area (for example, an area of 25 cm ² when the heat-conductive sheet is 5 cm x 5 cm) when subjected to a drying treatment at 180 ° C for one hour under normal pressure .

≪ Resin composition and resin composition layer >

Here, a resin composition containing thermally conductive particles and a thermosetting resin, which can be suitably used in the method for producing a thermally conductive sheet of the present invention, will be described. In the following description, the reference numerals are omitted.

The thermosetting resin used in the present invention is not particularly limited as long as it is cured by heat and has an adhesive action, and an epoxy resin is usually used. The epoxy resin is not particularly limited as long as it is cured and exhibits an adhesive action, and is preferably a bifunctional or more epoxy resin containing two or more epoxy groups in one molecule. The weight average molecular weight of the epoxy resin is preferably 300 or more and less than 5000, and more preferably 300 or more and less than 3000 in order to maintain good flexibility of the adhesive film. Examples of the bifunctional epoxy resin containing two epoxy groups in a molecule include bisphenol A type or bisphenol F type epoxy resin. Examples of the trifunctional or higher functional epoxy resin containing three or more epoxy groups in a molecule include phenol novolak type epoxy resin and cresol novolak type epoxy resin.

When a bifunctional epoxy resin and a trifunctional or higher-functional epoxy resin are used in combination, a mixture of 50 parts by mass to 100 parts by mass of a bifunctional epoxy resin and 0 parts by mass to 50 parts by mass of a trifunctional or more epoxy resin Mass part is preferably used. Particularly, it is preferable to use 50 parts by mass to 90 parts by mass of bifunctional epoxy resin and 10 parts by mass to 50 parts by mass of trifunctional or more epoxy resin for high Tg (glass transition temperature).

The epoxy resin usable in the present invention may be a liquid epoxy resin or a combination of a solid epoxy resin and a liquid epoxy resin. Examples of the liquid epoxy resin include a liquid bisphenol A type epoxy resin, a naphthalene type bifunctional epoxy resin, a liquid bisphenol AF type epoxy resin, and a hydrogenated epoxy resin. The liquid epoxy resin is preferably contained in an amount of 10 parts by mass or more based on the total amount of the epoxy resin to be used, from the viewpoints of coatability and adhesiveness.

A curing agent may be added to the resin composition of the present invention. When the thermosetting resin is an epoxy resin, the curing agent usable in the present invention is not particularly limited as long as it is a commonly known epoxy resin curing agent. Examples of the curing agent when the thermosetting resin is an epoxy resin include bisphenol A, bisphenol F, bisphenol S, etc. which are compounds having two or more amines, polyamides, acid anhydrides, polysulfides, boron trifluoride and phenolic hydroxyl groups in one molecule , Phenol resins such as phenol novolac resins, modified phenol novolac resins, bisphenol A novolac resins and cresol novolak resins. Particularly, a phenol resin such as phenol novolac resin, bisphenol novolac resin or cresol novolac resin is preferable from the viewpoint of excellent corrosion resistance such as moisture absorption.

The epoxy resin curing agent is compounded so that the total amount of reactive groups in the curing agent is preferably 0.6 equivalents to 1.4 equivalents, more preferably 0.8 equivalents to 1.2 equivalents, based on 1 equivalent of the epoxy group of the epoxy resin. By setting the thickness within the above range, the heat-conductive sheet can secure adhesiveness and strength after curing, and as a result, heat resistance can be ensured. Even if the blending amount of the curing agent is less than 0.6 equivalent, the heat resistance tends to be lowered even when it exceeds 1.4 equivalent.

A curing accelerator may be added to the resin composition of the present invention. Examples of the curing accelerator used in the present invention include imidazole, triphenylphosphine, quaternary phosphonium salt, quaternary ammonium salt, DBU fatty acid salt, metal chelate, and metal salt. Examples of the imidazole-based curing accelerator include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, Imidazolium trimellitate, and the like. In addition, the latent curing accelerator is suitably used because the lying period of the heat conduction sheet is long. Typical examples of the latent curing accelerator include dihydrazide compounds such as dicyandiamide and adipic acid dihydrazide, adducts of a guanamine acid, a melamine acid, an epoxy compound and an imidazole compound, an epoxy compound and a dialkylamine An addition compound, an addition compound of amine and thiourea, an addition compound of amine and isocyanate, and the like, but are not limited thereto. A compound having an adduct-type structure is particularly preferable in that the activity at room temperature can be reduced. A compound having an adduct-type structure means an adduct obtained by reacting a compound having a catalytic activity with various compounds. As the duct type curing accelerator, an amine adduct type curing accelerator using a compound having a catalytic activity, an amine compound such as a compound having a primary amino group, a secondary amino group or a tertiary amino group, or an imidazole compound. The amine-duct type curing accelerator may be an amine-epoxy adduct type, an amine-element adduct type, or an amine-urethane adduct type depending on the kind of raw material.

The blending amount of the curing accelerator is preferably 0.1 parts by mass to 20 parts by mass, more preferably 0.5 parts by mass to 15 parts by mass, based on 100 parts by mass of the total amount of the epoxy resin and the curing agent. When the blending amount of the curing accelerator is 0.1 parts by mass or more, the decrease in the curing rate tends to be suppressed. When the blending amount is 20 parts by mass or less, shortening of the writing time tends to be avoided.

The thermally conductive particles are not particularly limited as long as they are thermally conductive particles. Examples of the thermally conductive particles include aluminum nitride, hexagonal boron nitride, cubic boron nitride, silicon nitride, diamond, alumina, aluminum oxide, magnesium oxide, silicon nitride, gallium nitride, silicon carbide, silicon dioxide, talc, mica, aluminum hydroxide, And the like. From the viewpoint of increasing the filling rate of the thermally conductive particles in order to enhance the thermal conductivity of the heat conduction sheet, it is preferable to use cubic boron nitride or alumina. As the two or more types of thermally conductive particles, combinations of aluminum oxide, boron nitride, aluminum nitride and the like and heat conductive particles other than those listed above, which have a high thermal conductivity among the above-listed types, can be considered. For example, aluminum oxide and talc; Boron nitride and aluminum hydroxide; .

Particularly, it is preferable that at least three kinds of thermally conductive particles include fillers having different volume average particle diameters. Among the fillers, the first filler can be a filler having a volume average particle diameter of 0.01 mu m or more and less than 1 mu m. The volume average particle diameter of the first filler is preferably 0.05 mu m or more and 0.8 mu m or less from the viewpoint of dispersibility and more preferably 0.1 mu m or more and 0.6 mu m or less in view of packing.

The second filler can be a filler having a volume average particle diameter of 1 占 퐉 or more and less than 10 占 퐉. The volume average particle diameter of the second filler is preferably 2 mu m or more and 8 mu m or less in view of the melt viscosity of the resin, and more preferably 2 mu m or more and 6 mu m or less from the viewpoint of filling property.

The third filler can be a filler having a volume average particle diameter of 10 mu m or more and 60 mu m or less. From the viewpoint of the insulating property, the volume average particle diameter of the third filler is preferably 15 mu m or more and 55 mu m or less, and more preferably 20 mu m or more and 50 mu m or less from the viewpoint of thermal conductivity.

In addition, by including three kinds of fillers having different volume average particle diameters, the filling rate of the filler is improved and the thermal conductivity is improved more effectively. The first filler, the second filler and the third filler are selected so as to have a volume average particle diameter within the above-mentioned volume average particle diameter and having different volume average particle diameters from each other.

The filler may be a combination of a first filler having a volume average particle diameter of not less than 0.01 탆 and less than 1 탆, a second filler having a volume average particle diameter of not less than 1 탆 and less than 10 탆 and a third filler having a volume average particle diameter of not less than 10 탆 and not more than 60 탆 A first filler having a volume average particle diameter of 0.05 mu m or more and 0.8 mu m or less and a second filler having a volume average particle diameter of 2 mu m or more and 8 mu m or less and a third filler having a volume average particle diameter of 15 mu m or more and 55 mu m or less A second filler having a volume average particle diameter of not less than 0.1 mu m and not more than 0.6 mu m and a second filler having a volume average particle diameter of not less than 2 mu m and not more than 6 mu m and a third filler having a volume average particle diameter of not less than 20 mu m and not more than 50 mu m, As shown in FIG.

The volume average particle diameter of the filler is measured using a laser diffraction scattering method. In the case of using the laser diffraction scattering method, the filler is firstly extracted from the resin composition or the resin sheet (including the cured product) and measured by using a laser diffraction scattering particle size distribution measuring apparatus (for example, LS230 manufactured by Beckman Coulter Co.) Do. In addition, the measurement includes a dry method and a wet method, and a wet method is preferable. Specifically, a filler component is extracted from a resin composition or a resin sheet by using an organic solvent, nitric acid, or aqua regia, and sufficiently dispersed by an ultrasonic disperser or the like to prepare a dispersion. By measuring the particle size distribution of the dispersion, the volume average particle size of the filler can be measured.

The first filler, the second filler and the third filler in the present invention each have the volume average particle diameter. (Volume average particle diameter of the second filler / volume average particle diameter of the first filler) of the volume-average particle diameter of the second filler to the volume average particle diameter of the first filler is preferably 5 to 50 from the viewpoints of heat conductivity, , And more preferably 8 to 20 from the viewpoints of the filling property and the thermal conductivity.

(Volume average particle diameter of the third filler / volume average particle diameter of the second filler) of the volume-average particle diameter of the third filler to the volume average particle diameter of the second filler is 3 to 40 from the viewpoint of thermal conductivity and insulation More preferably from 5 to 30 carbon atoms.

In the present invention, the first filler, the second filler, and the third filler each have a predetermined volume average particle diameter, and the particle diameter distribution thereof is not particularly limited, but it is preferable that the first filler, the second filler and the third filler have a wide particle size distribution from the viewpoint of thermal conductivity .

The filler in the present invention may be any one that includes the first filler, the second filler, and the third filler as the whole filler. That is, when the particle diameter distribution of the whole filler is measured, the peak corresponding to the first filler having a volume average particle diameter of 0.01 mu m or more and less than 1 mu m and the peak corresponding to the second filler having a volume average particle diameter of 1 mu m or more and less than 10 mu m , And at least three peaks of a peak corresponding to a third pillar having a volume average particle diameter of 10 mu m or more and 60 mu m or less may be observed.

The filler of this embodiment may be constituted by mixing the first filler, the second filler and the third filler which exhibit a single peak in the particle diameter distribution, respectively, and may also be constituted by using a filler having two or more peaks in the particle diameter distribution .

In the present invention, it is preferable that the content ratio of the first filler, the second filler, and the third filler is 1 volume% to 15 volume% and the content of the second filler is 10 Volume percentage to 40 volume%, and the content ratio of the third filler is in the range of 45 volume% to 80 volume% and the total amount is 100 volume%. It is preferable that the content of the first filler is 6 vol% to 15 vol%, the content of the second filler is 18 vol% to 35 vol%, the content of the third filler is 50 vol% to 70 vol% %, And more preferably 100% by volume in total.

Further, by increasing the proportion of the third filler to the maximum level and then increasing the content ratio of the second filler, the thermal conductivity can be more effectively improved. By including at least three kinds of fillers differing in volume average particle size in such a specific content ratio (volume basis), the thermal conductivity is more effectively improved.

The third filler may contain at least boron nitride, and may further contain an inorganic compound having other insulating properties in addition to boron nitride. The third filler having a specific volume average particle diameter contains boron nitride, so that the thermal conductivity is remarkably improved.

The content of boron nitride contained in the third filler is not particularly limited. From the viewpoint of thermal conductivity, it is preferably 60 vol% or more, more preferably 80 vol% or more, further preferably 100 vol%, when the total amount of the third filler is 100 vol%.

The inorganic filler other than boron nitride which can be included in the third filler is also the same as the first filler and the second filler described later.

On the other hand, as the first filler and the second filler, an inorganic compound having an insulating property is not particularly limited, but it is preferable to have a high thermal conductivity.

Specific examples of the first filler and the second filler include aluminum oxide, magnesium oxide, boron nitride, aluminum nitride, silicon nitride, talc, mica, aluminum hydroxide, barium sulfate and the like. Of these, aluminum oxide, boron nitride, or aluminum nitride are preferable from the viewpoint of thermal conductivity. As the material of these fillers, one type may be used alone, or two or more types may be used in combination.

The particle shape of the filler is not particularly limited, and examples thereof include spherical, rounded, crushed, scaly, and aggregated particles. Among them, a rounding type or an aggregated particle type is preferable from the viewpoints of the filling property and the thermal conductivity.

In the present invention, the total proportion of the filler content in the resin composition is not particularly limited, and is preferably 50% by volume to 90% by volume of the total solid content of the resin composition from the viewpoint of thermal conductivity and adhesiveness, And more preferably 50 vol.% To 85 vol.%.

The total solid content of the resin composition means the total mass of the non-volatile component among the components constituting the resin composition.

In the present invention, a coupling agent may be added to facilitate interfacial bonding between dissimilar materials. Examples of the coupling agent include a silane coupling agent, a titanate coupling agent, and an aluminum coupling agent. Of these, a silane coupling agent is preferred. The compounding amount of the coupling agent is preferably 0.1 part by mass to 10 parts by mass with respect to 100 parts by mass of the total amount of the resin composition in terms of the effect of addition, heat resistance and cost. Examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureidopropyltriethoxysilane, N-β- Aminopropyl-γ-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, and 3-methacryloxypropyltriethoxysilane.

In the present invention, a dispersant may be added for the purpose of improving the dispersibility of thermally conductive particles or other fillers. As the dispersing agent, there can be mentioned a polymer dispersing agent such as a graft polymerization type dispersing agent, a hydroxyl group-containing system dispersing agent, an amino group-containing system dispersing agent, and a carboxylic acid-containing system dispersing agent. In order to more stably disperse the particles, a low molecular weight dispersant called wetting agent having a function of wetting the particle surface may be used in combination with the polymer dispersant. The dispersing agent may be used singly or in combination of two or more. The blending amount of the dispersing agent is preferably 0.05 part by mass to 15 parts by mass with respect to 100 parts by mass of the total amount of the resin composition.

In the present invention, an elastomer resin may be blended for the purpose of improving the toughness of the thermally conductive sheet. The elastomer resin is a thermoplastic elastomer resin which exhibits rubber elasticity like vulcanized rubber at room temperature and is plasticized at a high temperature to have good processability. Examples of the elastomer resin include a polyester elastomer, an olefin elastomer, a styrene butadiene block copolymer, a urethane elastomer, a polyamide elastomer, and an ionomer elastomer. These elastomers may be used singly or in combination of two or more thereof .

As the method for producing the resin composition, a method for producing the resin composition to be usually used can be used without particular limitation. For example, as a method of mixing an epoxy resin, a novolac resin, a filler and the like, a dispersing device such as an ordinary stirrer, a kneader, a three-roll mill or a ball mill may be suitably combined. Further, an appropriate organic solvent may be added to perform dispersion and dissolution.

Concretely, for example, a resin composition can be obtained by dissolving and dispersing an epoxy resin, a novolak resin, a filler, and a silane coupling agent in an appropriate organic solvent and, if necessary, mixing other components such as a curing accelerator.

The organic solvent is dried and desorbed by a drying step in a resin sheet production method described later, and if it remains in a large amount, it affects the thermal conductivity or the insulation performance, and therefore, it is preferable that the boiling point or the vapor pressure is low. In addition, if it is completely lost, the sheet becomes hard and the adhesive performance is lost, so that it is necessary to suit the drying method, conditions and the like.

When the varnish of the resin composition comprising the thermally conductive particles and the thermosetting resin is coated on the substrate in the production process of the film, the solid content (nonvolatile component) of the varnish is preferably 30 mass% or more of the total mass of the varnish. The solid content (nonvolatile component) of the varnish is a value obtained as the mass remaining ratio per unit volume of the varnish unit (for example, varnish volume 1 cm ³ ) when the drying treatment is performed at 180 ° C for 30 minutes under normal pressure.

When considering the dispersibility of the filler component containing the thermally conductive particles, the varnish can be prepared by using a kneader, a three-roll mill, a bead mill or the like or a combination thereof. When a component having a different molecular weight exists in the resin composition, it is possible to shorten the time required for mixing by mixing a filler component and a low molecular weight component in advance and then blending a high molecular weight component. It is also preferable to remove the bubbles in the varnish by vacuum degassing after making the varnish.

In the present invention, there is no particular limitation on the solvent used in producing the varnish. Examples of the solvent include methyl ethyl ketone, acetone, methyl isobutyl ketone, 2-ethoxy ethanol, toluene, butyl cellosolve, methanol, ethanol, 2-methoxyethanol, dimethylacetamide, dimethylformamide, , Cyclohexanone, and the like. Among them, a high boiling solvent such as dimethylacetamide, dimethylformamide, methylpyrrolidone, cyclohexanone and the like is preferable for the purpose of improving the film property. These solvents may be used singly or in combination of two or more kinds.

Examples of the substrate for forming the film include a polyethylene terephthalate film, a polytetrafluoroethylene film, a polyethylene film, a polypropylene film, a polymethylpentene film, a polyimide film, a polyethylene naphthalate film, a polyethersulfone film, Amide films, polyether amide imide films, polyamide films, and polyamideimide films. In addition, a substrate made of a metal such as copper, aluminum, nickel, iron, or silver may be used. The substrate may be subjected to surface treatment such as primer coating, UV treatment, corona discharge treatment, polishing treatment, etching treatment, and release treatment, if necessary. As the substrate for forming the film using the varnish of the resin composition, a polyethylene terephthalate film is preferable from the viewpoints of the temperature range, the modulus of elasticity, and the surface smoothness which can be used.

Specifically, as a method for producing the film, a resin composition (varnish) containing an organic solvent is applied on a substrate so as to have a desired average film thickness to form a coating layer, and the formed coating layer is heated and dried to form an organic solvent And at least a part of them is removed (dried).

The coating method and the drying method of the resin composition can be appropriately selected from commonly used methods without any particular limitation. Examples of the application method include a method using a comma coater or a die coater, and a dip coating method. Examples of the drying method include heat drying under normal pressure or reduced pressure, natural drying, freeze drying and the like.

The thickness of the coating layer may be appropriately selected depending on the purpose, and may be, for example, from 50 m to 250 m, and preferably from 100 m to 200 m.

In the present invention, the film obtained from the resin composition is formed on a substrate, and the obtained base-attached film is used in the production method of the present invention.

The thermally conductive sheet obtained by the production method of the present invention may also be a thermally conductive sheet with a metal foil, by attaching a thermally conductive metal foil such as copper or aluminum to the surface. As a result, the thermal conductivity can be further increased. As a condition for attaching the foil of the thermally conductive metal, the temperature is a temperature at which the thermosetting resin is not completely cured, specifically, not less than 100 ° C and not more than 200 ° C, and a pressure of not less than 1 MPa and not more than 20 MPa .

The thermally conductive sheet or the thermally conductive sheet with a metal foil according to the present invention can also be thermally cured to obtain a thermally conductive sheet or a cured product of the thermally conductive sheet with a metal foil.

The heat treatment conditions for producing the cured product of the heat conductive sheet can be appropriately selected depending on the constitution of the resin composition. For example, at 120 to 250 캜 for 10 minutes to 300 minutes. Further, from the viewpoint of the thermal conductivity, it is preferable to include a temperature at which a higher-order structure is easily formed, and it is more preferable to carry out at least two stages of heating, for example, from 100 캜 to 160 캜 and from 160 캜 to 250 캜. In addition, it is more preferable to carry out a multi-stage heat treatment in two or more stages in the above temperature range.

As described above, the heat conductive sheet with a metal foil may have a high thermal conductivity and an insulating property, and is also flexible enough to be mounted on a semiconductor device or the like, so that it may constitute a part of a semiconductor device. A semiconductor device including such a heat conductive sheet is used for a power control unit and an LED (Light Emitting Diode) for mounting on a car.

Example

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Example 1)

, 4.5 parts by mass of a phenol novolak type epoxy resin (EPPN-201, manufactured by Nippon Kayaku Co., Ltd.), 4.5 parts by mass of a liquid bisphenol AF type epoxy resin (Epototo ZX-1059 manufactured by Tohto Kasei Co., , 6 parts by mass of a low water absorbing phenol resin (trade name: XLC-LL manufactured by Mitsui Chemicals, Inc.), 0.09 parts by mass of triphenylphosphine (Kanto Kagaku Co., Ltd.) as a curing accelerator, (Manufactured by Shin-Etsu Chemical Co., Ltd., KBM-573), 0.11 parts by mass of a hydroxyl group-containing polymer salt (DISKERM-JAPAN, DISPERBYK-106) as a dispersant, and 0.11 parts by mass of an alumina filler [Sumitomo Chemical Co., (First filler) 9 parts by mass, Sumitomo Chemical Co., Ltd., Sumikolan Dam AA04 (average particle size: 3 占 퐉): Second filler] 21 parts by mass, alumina filler Boron [Mizushima Ferroalloy Co., Ltd., HP-40 (average particle size 18 ㎛): a third filler] were each weighed 32 parts by weight, as a solvent of cyclohexanone (Wako Junya Ku Industry Co., Ltd.) 23 parts by weight.

The weighed material was mixed with a ball mill. In the ball mill, in that the weighed materials and alumina balls 75 mm in diameter 5 parts by mass of the shroud into the bottle with a poly (volume 2 liters) placed on the two rotor tabletop, the tabletop 100 two rotor min ^-1 (Rotation / minute). At this time, 1 part by mass of cyclohexanone was added to adjust the viscosity. After completion of the mixing, vacuum degassing was conducted using a vacuum pump to obtain a varnish having a solid content of 76% by mass. The viscosity of the varnish was 3.2 Pa · s as measured by a cone plate type rotational viscometer RE100 (manufactured by Toki Industries Co., Ltd.) at a rotation speed of 5 min ^-1 (rotation / minute) in a thermostat set at 25 ° C.

Next, the varnish was applied to a substrate. Polyethylene terephthalate (Purex A53, manufactured by DAIZIN CO., LTD.) Was used as a substrate. The substrate width was 400 mm, and the coating width was 350 mm. The coating was performed with a comma coater, and the coating gap was set to 275 m and the conveying speed to 0.7 m / min. After the film was formed, 30 m of a film was obtained on the substrate by drying for 7 minutes in an oven set at a temperature of 120 캜. A sample of 5 cm x 5 cm in size was cut out from the dried film and dried at 180 DEG C for 1 hour under normal pressure. The mass was measured by a precision balance to calculate the residual volatile content as a rate of decrease from the mass of the film before the drying treatment did. The residual volatile matter of the obtained film was 1.1% by mass and the average film thickness was 125 占 퐉. The mass per unit area (100 cm ² ) of the obtained film was 2.76 g. Here, the film thickness of the design value of the heat transfer sheet because a 200 ㎛, when using the theoretical density of the heat conductive sheet 2.3 g / cm ³ calculates the mass design values of the heat transfer sheet to be 4.6 g, as a result, the mass of the obtained film The multiple was 0.60 times. An unfixed polyethylene film (NF-15 manufactured by Tama Poly Co., Ltd.) was stuck as a protective film on the coated side of the obtained film.

Two rolls of the film 7 having the base material and the protective film thus obtained as described above were notified (passed) to the production apparatus 50 shown in Fig. The production apparatus 50 is capable of applying pressure in the film thickness direction of the film laminate 4 by four rolls.

The holding angle? Of the substrate adhering film 3A with respect to the first roll 52A was set to 95 ° and the holding angle? 'With respect to the second roll 52B of the base material affixing film 3B was set to 95 ° Setting.

Both the surface temperature of the first roll 52A and the surface temperature of the second roll 52B were set at 65 占 폚. The line pressure in the film thickness direction of the film laminate (4) in the base film laminate (5) was set at 15 kN / m.

The substrate attachment films 3A and 3B after the protective film 6 is peeled are first passed through the gap between the first roll 52A and the second roll 52B to form the film laminate 4 in the film thickness direction Lt; / RTI >

The film laminate 4 with the pressure applied in the film thickness direction is pressed by the first roll 52A and the second roll 52B and the third roll 52C and the fourth roll 52D are moved in the film thickness direction Lt; / RTI > The surface temperature of the third roll 52C and the surface temperature of the fourth roll 52D were both set at 45 占 폚. The linear pressure applied to the film laminate 4 by the third roll 52C and the fourth roll 52D in the film thickness direction was set at 10 kN / m.

After the base material 1A on the upper face side of the film laminated body 4 in which the pressure is applied in the film thickness direction by the third roll 52C and the fourth roll 52D is peeled off and then the winding side nip rolls 22A, , The protective film 6 was stuck on the film laminate 4 of the surface on which the base material 1A was peeled off. As the protective film 6, an unfixed polyethylene film (NF-15 manufactured by Tama Poly Co., Ltd.) was used. The film laminate 8 on which the protective film 6 was attached and the substrate after the pressing and the protective film were wound was wound such that the side of the side to which the protective film 6 was pasted was inward.

Only the film laminate 4 was peeled off from the film laminate 8 with the protective film 6 attached thereto and the protective film attached thereon using a rectangular adhesive tape and the average film thickness was measured. 213 탆. As described above, since the average film thickness of the film was 125 占 퐉, the film thickness reduction rate from the equation (2) was 85%. As the rectangular adhesive tape, a non-adhesive type polyethylene, polyester, or the like can be used.

Further, a film laminate 8 having a size of 100 mm x 100 mm and a protective film adhered thereto was extracted from the film laminate 8 having the protective film 6 attached thereto and the protective film attached thereto, The film and the substrate were peeled off using a rectangular adhesive tape, and a sample of the film laminate 4 was collected. A glossy surface of a copper foil (GTS-105 manufactured by Nippon Electric Electric Co., Ltd.) having a thickness of 105 탆 was attached to both sides of the sample of the collected film stack 4 with a flat plate press. The conditions of the flat press were a temperature of 180 占 폚, a pressure of 12 MPa, and a time of 5 minutes under vacuum (15 mmHg (2.0 kPa) or less). In order to completely cure the thermosetting resin forming the film laminate 4 in which the copper foil was attached to both surfaces with a flat press, the film was heated at 150 占 폚 for 30 minutes and further at 190 占 폚 for 120 minutes by an explosion-proof dryer. Thus, a film laminate obtained by completely curing the thermosetting resin was obtained as the heat conductive sheet with copper foil.

In order to measure the thermal resistance of the copper-clad heat-conducting sheet, it was cut into test pieces of 10 mm x 10 mm, sandwiched between the transistor (2SC2233) and the cooling copper heat sink, From measuring the temperature of the transistor T1 (℃), temperature T2 (℃) of the copper heat sink, and the measured values and the applied electric power W1 (W), and the area S (cm ²⁾ of the heat conductive sheet test piece, the following formula (3) As a result of calculating the heat resistance X (占 폚 / W), the thermal resistance was 0.184 (占 폚 / W).

X = (T1-T2) / W1 / S (3)

Next, in order to measure the film thickness, density, specific heat, thermal conductivity, and dielectric strength of the thermally conductive sheet, the thermally conductive sheet with the copper foil was immersed in an aqueous ammonium persulfate solution and etched to remove the copper foils on both sides.

The film thickness, density, and specific heat of the heat conductive sheet after removal of the copper foil were measured. The average film thickness was 207 탆. Density was measured by dipping method using Archimedes' principle. The apparatus used was MD-300S manufactured by ALFA MIRAGE, and the density was found to be 2.26 g / cm < ³ >. The specific heat was 0.87 J / (g · K) as measured by DSC (differential scanning calorimeter) based on the specific heat capacity measurement method of the plastic specified in JIS K7123.

In order to obtain the thermal conductivity of the heat conductive sheet, the heat conductive sheet from which the copper foil was removed was cut out with a test piece of 100 mm x 100 mm size, and both surfaces were blackened with a graphite spray. The test piece 25 ℃ a constant temperature bath set to the setting, measuring the thermal diffusivity of the film thickness direction of the heat conductive sheet using the Nanoflash LFA447 type flash method thermal diffusivity measuring apparatus manufactured by NETZSCH bar, 5.73 mm ² / s was. The thermal conductivity was calculated from the obtained thermal diffusivity, specific heat and density by the following equation (4). As a result, the thermal conductivity was 11.3 W / (m · K).

Thermal conductivity [W / (m · K)]

= Heat diffusivity (mm ² / s) × specific heat [J / (g · K)] × density (g / cm ³ )

The dielectric strength was measured by an insulation breakdown test. The voltage at which the insulation breakdown occurred when the voltage was applied to the heat conductive sheet in the machine was set to the insulation withstand voltage at a boosting speed of 500 V / s. The measurement was carried out on five points of a test piece of a heat conductive sheet having a size of 100 mm x 100 mm, and the minimum value of the measured values was adopted. As a result, the dielectric strength was 8.6 kV.

(Example 2)

Two rolls of the film having the same composition and the same manufacturing conditions as those of Example 1 and having the base material and the protective film attached were notified to the production apparatus 10 shown in Fig. 4 to produce a heat conductive sheet.

The holding angle? Of the substrate adhering film 3A in the manufacturing apparatus 10 with respect to the first roll 12A and the holding angle? 'With respect to the second roll 12B of the base material attachment film 3B are respectively 95 °.

The surface temperature of the first roll 12A and the surface temperature of the second roll 12B were both set at 65 占 폚. The conveying speed of the films 2A and 2B was set at 0.4 m / min (minute). The linear pressure applied to the film laminate 4 by the first roll 12A and the second roll 12B in the film thickness direction was set at 15 kN / m.

After the base material 1A on the upper face side of the film laminate 4 with the pressure applied in the film thickness direction by the first roll 12A and the second roll 12B is peeled off and then the winding side nip rolls 22A, , The protective film 6 was stuck on the film laminate 4 of the surface on which the base material 1A was peeled off. As the protective film, a non-sticky polyethylene film (NF-15 manufactured by Tama Poly Co., Ltd.) was used. The film laminate 8 on which the protective film 6 was attached and the substrate after the pressing and the protective film were wound was wound such that the side of the side to which the protective film 6 was pasted was inward.

Only the film laminate 4 was peeled off from the film laminate 8 with the protective film 6 attached thereto and the protective film attached thereon using a rectangular adhesive tape and the average film thickness was measured. 210 탆. As described above, since the average film thickness of the film was 125 占 퐉, the film thickness reduction rate from equation (2) was 84%.

From the obtained film laminate 4, the thermal resistance of the copper-clad heat-conductive sheet produced in the same manner as in Example 1 was 0.178 (占 폚 / W). Further, the heat conduction sheet after the copper foil is removed, 204 ㎛ thickness, density 2.27 g / cm ^3, the specific heat was 0.87 J / (g · K) . Further, the thermal diffusivity was 5.81 mm ² / s. As a result, the thermal conductivity was found to be 11.5 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 8.5 kV.

(Example 3)

Two rolls of the film with the base material and the protective film, which had been prepared in the same manner as in Example 2 and under the same manufacturing conditions, were notified to the production apparatus 10 shown in Fig. 4 in the same manner as in Example 2, .

The holding angle? Of the substrate adhering film 3A with respect to the first roll 12A in the manufacturing apparatus 10 and the holding angle? 'With respect to the second roll 12B of the base material adhering film 3B are respectively 80 ° Respectively. The conditions other than the holding angle were the same as those in Example 2.

The average film thickness of the film laminate 4 alone was measured from the film laminate 8 on which the protective film 6 was stuck and the protective film, and it was found to be 207 탆. As described above, since the average film thickness of the film was 125 占 퐉, the film thickness reduction rate was 83% from the formula (2).

The thermal resistance of the copper-clad heat-conductive sheet prepared in the same manner as in Example 1 from the obtained film laminate 4 was 0.174 (占 폚 / W). The heat-conductive sheet after removal of the copper foil had a thickness of 202 탆, a density of 2.28 g / cm ³ and a specific heat of 0.87 J / (g · K). The thermal diffusivity was 5.85 mm ² / s. As a result, the thermal conductivity was found to be 11.6 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 8.5 kV.

(Example 4)

When a film was coated with a comma coater using a varnish and a substrate having the same composition as in Example 1, the coating gap was set at 260 탆. The drying conditions were the same as in Example 2, the temperature was set at 120 캜, the conveying speed was set at 0.7 m / min, and the drying time was set at 7 minutes. A sample of 5 cm x 5 cm in size was cut out from the dried film and dried at 180 DEG C for 1 hour under normal pressure. The mass was measured by a precision balance to calculate the residual volatile content as a rate of decrease from the mass of the film before the drying treatment did. The residual volatile matter of the obtained film was 1.15 mass% and the average film thickness was 119 占 퐉. The mass per unit area (100 cm ² ) was 2.4 g, and the mass design value of the heat-conducting sheet was 4.6 g as described above, so that the mass ratio of the resulting film was 0.52 times.

A thermally conductive sheet was produced from the 2 rolls of the obtained film having the base material and the protective film, using the production apparatus 10 in the same manner as in Example 3.

The manufacturing conditions of the step of applying pressure in the film thickness direction of the film laminate 4 in the substrate laminated film 5 with the first roll 12A and the second roll 12B were the same as those in Example 3 . As a result, the average film thickness of only the film laminate 4 after pressurization, which was taken from the film laminate 8 having the base film and the protective film attached thereto, was 201 占 퐉. As described above, , The film thickness reduction rate was found to be 84% from the equation (2).

The thermal resistance of the copper-clad heat-conductive sheet prepared in the same manner as in Example 1 from the obtained film laminate 4 was 0.170 (占 폚 / W). The heat-conductive sheet after the removal of the copper foil had a thickness of 199 탆, a density of 2.29 g / cm ³ and a specific heat of 0.87 J / (g · K). The heat diffusivity was 5.86 mm ² / s. As a result, the thermal conductivity was found to be 11.7 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 8.3 kV.

(Example 5)

Varnishes and substrates having the same composition as in Example 1 were used. After the film was coated with a comma coater, the drying temperature was 120 ° C, the conveying speed was 0.6 m / min, and the drying time was 8 minutes. A sample of 5 cm x 5 cm in size was cut out from the dried film and dried at 180 DEG C for 1 hour under normal pressure. The mass was measured by a precision balance to calculate the residual volatile content as a rate of decrease from the mass of the film before the drying treatment did. As a result, the residual volatile matter of the obtained film was 0.7% by mass and the average film thickness was 118 占 퐉. Further, the mass per unit area (100 cm ² ) was 2.4 g, and the mass design value of the heat conductive sheet was 4.6 g as described above. As a result, the mass ratio of the obtained film was 0.52 times.

A thermally conductive sheet was produced from 2 rolls of the obtained base material-adhering film by using the production apparatus 10 in the same manner as in Example 4.

The production conditions of the step of applying pressure in the film thickness direction of the film laminate 4 in the substrate laminated film 5 with the first roll 12A and the second roll 12B were the same as those in Example 4 And the average film thickness of only the film laminate 4 obtained from the film laminate 8 on which the protective film 6 was adhered and the protective film was attached was 199 μm, (118), the film thickness reduction rate was 84% from the equation (2).

Further, the thermal resistance of the copper foil-attached thermally conductive sheet produced from the obtained film laminate 4 was 0.167 (占 폚 / W). Further, after removing the copper foil sheet is heat conductive, and the average film thickness of 197 ㎛, density was 2.29 g / cm ^3, the specific heat 0.87 J / (g · K) . The thermal diffusivity was 5.91 mm ² / s. As a result, the thermal conductivity was found to be 11.8 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 8.8 kV.

In Examples 6 to 9 below, the same film as in Example 5 was used.

(Example 6)

The same as Example 5 except that both the surface temperature of the first roll 12A and the surface temperature of the second roll 12B in the manufacturing apparatus 10 were set at 80 占 폚. Only the film laminate 4 was taken out from the film laminate 8 with the protective film 6 attached thereto and the protective film attached thereto, and the average film thickness was measured to be 198 탆. As described above, since the average film thickness of the film was 118 占 퐉, the film thickness reduction rate was 84% from the equation (2).

The thermal resistance of the copper-clad heat-conductive sheet prepared in the same manner as in Example 1 from the obtained film laminate 4 was 0.165 (占 폚 / W). The heat-conductive sheet after removal of the copper foil had an average film thickness of 196 탆, a density of 2.29 g / cm ³ and a specific heat of 0.87 J / (g · K). Further, the thermal diffusivity was 5.95 mm ² / s. As a result, the thermal conductivity was found to be 11.9 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 8.8 kV.

(Example 7)

The manufacturing conditions of the step of applying pressure in the film thickness direction of the film laminate 4 and the manufacturing apparatus used were the same as those of Example 6 except that the conveying speed of the films 2A and 2B was set at 1 m / min. The average film thickness of the film laminate 4 taken from the film laminate 8 on which the protective film 6 was stuck and the protective film was only 198 占 퐉. As described above, since the average film thickness of the film was 118 占 퐉, the film thickness reduction rate was 84% from the equation (2).

The thermal resistance of the copper-clad heat-conductive sheet prepared in the same manner as in Example 1 from the obtained film laminate 4 was 0.165 (占 폚 / W). The heat-conductive sheet after removal of the copper foil had an average film thickness of 196 탆, a density of 2.29 g / cm ³ and a specific heat of 0.87 J / (g · K). Further, the thermal diffusivity was 5.96 mm ² / s. As a result, the thermal conductivity was found to be 11.9 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 9.0 kV.

(Example 8)

The production conditions of the step of applying the pressure in the film thickness direction of the film laminate 4 and the manufacturing apparatus used are the same as those in the first and second rolls 12A and 12B in the film laminate 5 And the linear pressure applied to the film 4 in the film thickness direction was set to 40 kN / m. The average film thickness of only the film laminate 4 taken from the film laminate 8 on which the protective film 6 was stuck and the protective film was 196 mu m. As described above, since the average film thickness of the film was 118 占 퐉, the film thickness reduction rate was 83% from the formula (2).

The thermal resistance of the copper-clad heat-conductive sheet prepared in the same manner as in Example 1 from the obtained film laminate 4 was 0.161 (° C / W). The heat-conductive sheet after removal of the copper foil had an average film thickness of 193 탆, a density of 2.3 g / cm ³ and a specific heat of 0.87 J / (g · K). The thermal diffusivity was 5.98 mm ² / s. As a result, the thermal conductivity was found to be 12.0 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 9.1 kV.

(Example 9)

The production conditions of the step of applying the pressure in the film thickness direction of the film laminate 4 and the manufacturing apparatus used are the same as those in the first and second rolls 12A and 12B, Except that the line pressure applied to the laminate 4 in the film thickness direction was set to 80 kN / m. The average film thickness of only the film laminate 4 obtained from the base film to which the protective film 6 was attached and the film laminate 8 with the protective film attached was 188 탆. As described above, since the average film thickness of the film was 118 占 퐉, the film thickness reduction rate was 80% from the formula (2).

The thermal resistance of the copper-clad heat-conductive sheet produced from the obtained film laminate 4 was 0.153 (占 폚 / W). Further, after removing the copper foil sheet is heat conductive, and the average film thickness of 187 ㎛, density 2.34 g / cm ^3, the specific heat was 0.87 J / (g · K) . The thermal diffusivity was 6.01 mm ² / s. As a result, the thermal conductivity was found to be 12.2 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 9.4 kV.

(Example 10)

, 4.5 parts by mass of a phenol novolak type epoxy resin (EPPN-201, manufactured by Nippon Kayaku Co., Ltd.), 4.5 parts by mass of a liquid bisphenol AF type epoxy resin (Epototo ZX-1059 manufactured by Tohto Kasei Co., , 6 parts by mass of a low water absorbing phenol resin (trade name: XLC-LL manufactured by Mitsui Chemicals, Inc.), 0.09 parts by mass of triphenylphosphine (Kanto Kagaku Co., Ltd.) as a curing accelerator, 0.07 part by mass of bis (meth) acrylate (KBM-573 manufactured by Shin-Etsu Chemical Co., Ltd.), 0.11 part by mass of a hydroxyl group-containing polymer salt (DISPERBYK-106, manufactured by Big Chem Japan Co.) as a dispersant, 62 parts by mass of HP-40 (average particle size of 18 占 퐉), manufactured by Kokusan Co., Ltd., and 23 parts by mass of cyclohexanone (manufactured by Wako Pure Chemical Industries, Ltd.) as a solvent were respectively weighed.

The weighed material was mixed with a ball mill. In the ball mill, in that the weighed materials and alumina balls 75 mm in diameter 5 parts by mass of the shroud into the bottle with a poly (volume 2 liters) placed on the two rotor tabletop, the tabletop 100 two rotor min ^-1 (Rotation / minute). At this time, 1.2 parts by mass of cyclohexanone was added to adjust the viscosity. After completion of the mixing, vacuum degassing was conducted using a vacuum pump to obtain a varnish having a solid content of 77% by mass. The viscosity of the varnish was 3.3 Pa · s as measured by a cone plate type rotational viscometer RE100 (manufactured by Toki Industries Co., Ltd.) at a rotational speed of 5 min ^-1 (rotation / minute) in a thermostat set at 25 ° C.

Next, the varnish was applied to a substrate. Polyethylene terephthalate (Purex A53, manufactured by DAIZIN CO., LTD.) Was used as a substrate. The substrate width was 400 mm, and the coating width was 350 mm. The coating was carried out with a comma coater, and the coating gap was set at 280 μm and the transporting speed was set at 0.7 m / min. The coated sheet was placed in a drying furnace and dried at a temperature of 120 캜 for 7 minutes to obtain a film of 30 m on the substrate. A sample of 5 cm x 5 cm in size was cut out from the dried film and dried at 180 DEG C for 1 hour under normal pressure. The mass was measured by a precision balance to calculate the residual volatile content as a rate of decrease from the mass of the film before the drying treatment did. The residual volatile content of the obtained film was 0.9 mass% and the average film thickness was 121 占 퐉. The mass per unit area (100 cm ² ) of the obtained film was 2.45 g. Here, since the designed value of the film thickness of the heat conductive sheet was 200 占 퐉, the mass design value of the heat conductive sheet was 4.6 g, and as a result, the mass ratio of the obtained film was 0.53 times. An unfixed polyethylene film (NF-15 manufactured by Tama Poly Co., Ltd.) was stuck as a protective film on the coated side of the obtained film.

The manufacturing conditions of the step of applying the pressure in the film thickness direction of the film laminate 4 and the manufacturing apparatus used are the same as those of the ninth embodiment. The average film thickness of only the film laminate 4 taken from the film laminate 8 on which the protective film 6 was stuck and the protective film was 190 m. As described above, since the average film thickness of the film was 118 占 퐉, the film thickness decreasing rate from the equation (2) was 79%.

The thermal resistance of the copper-clad heat-conductive sheet prepared in the same manner as in Example 1 from the obtained film laminate 4 was 0.141 (占 폚 / W). Further, after removing the copper foil sheet is heat conductive, and the average film thickness of 187 ㎛, density 2.34 g / cm ^3, the specific heat was 0.88 J / (g · K) . The thermal diffusivity was 6.45 mm ² / s. As a result, the thermal conductivity was found to be 13.3 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 9.0 kV.

(Comparative Example 1)

In this comparative example, the same substrate as in Example 9 and a protective film-attached film were used.

Two 100 mm x 100 mm sizes were cut out from the substrate adhering films 3A and 3B after peeling off the protective film by using a rectangular adhesive tape from the base material and the protective film attachment film, The films 2A and 2B were opposed to each other and the substrate adhering films 3A and 3B were bonded to each other to obtain a substrate laminated film 5 having the base material attached thereto (product number: MHPC-V-100-610, type: B1240) . The conditions of the flat press at that time were a temperature of 150 DEG C under a vacuum (15 mmHg or less), a pressure of 12 MPa, and a time of 1 minute.

Only the film laminate 4 was taken out from the base film laminate 5. The average film thickness of the obtained film laminate (4) was 188 탆. As described above, since the average film thickness of the film was 118 占 퐉, the film thickness reduction rate was 80% from the formula (2).

Using the film laminate 4 obtained as described above, the copper foil was affixed with a flat plate press in the same manner as in Example 1 to obtain a heat conductive sheet with a copper foil. The obtained thermal conductive sheet with copper foil had a thermal resistance of 0.153 (占 폚 / W). Further, after removing the copper foil sheet is heat conductive, and the average film thickness of 185 ㎛, density 2.32 g / cm ^3, the specific heat was 0.87 J / (g · K) . The thermal diffusivity was 5.99 mm ² / s. As a result, the thermal conductivity was found to be 12.1 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 5.6 kV.

(Comparative Example 2)

When the materials weighed in the formulation shown in Example 1 were mixed into a ball mill, a varnish was prepared without adding 1 part by mass of cyclohexanone, which was carried out for the purpose of viscosity adjustment. As a result, a varnish of a solid content of 78 mass%, a viscosity of 3.4 Pa 占 퐏 (in a thermostat set at 25 占 폚 with a revolution of 5 min- ¹ (revolutions per minute)) was obtained.

Next, the varnish was applied to a substrate. Polyethylene terephthalate (Purex A53, manufactured by DAIZIN CO., LTD.) Was used as a substrate. The substrate width was 400 mm, and the coating width was 350 mm. The coating was performed with a comma coater, and the coating gap was set to 350 m and the conveying speed was set to 0.5 m / min. The coated sheet was dried in a drying oven at a temperature of 120 DEG C for 10 minutes to obtain a film having an average thickness of 135 mu m on the substrate. A sample of 5 cm x 5 cm in size was cut out from the dried film and dried at 180 DEG C for 1 hour under normal pressure. The mass was measured by a precision balance to calculate the residual volatile content as a rate of decrease from the mass of the film before the drying treatment did. The residual volatile content of the obtained film was 1.0% by mass. On the coated side of the obtained film, polyethylene terephthalate (Purex A53, manufactured by DAIZIN CO., LTD.) Was stuck as a protective film.

A sheet having a size of 100 mm x 100 mm was cut out from the obtained base material and the film having the protective film attached thereto and one film having the base material and the protective film adhered to each other in a vacuum (15 mmHg or less) The pressure was 12 MPa, and the pressure was 1 minute.

The base film after the pressing and the film having the protective film were peeled off using a rectangular adhesive tape so that the average film thickness of the film after peeling off the protective film was 130 占 퐉. Further, the thermal resistance of the copper-clad heat-conductive sheet produced from this film was 0.122 (° C / W). The heat-conductive sheet after the removal of the copper foil had a density of 2.25 g / cm ³ and a specific heat of 0.87 J / (g · K). The thermal diffusivity was 5.45 mm ² / s. As a result, the thermal conductivity was found to be 10.7 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 1.9 kV.

(Comparative Example 3)

The base material and the protective film-attached film produced in Comparative Example 2 were pressed in the film thickness direction only by one sheet of the production apparatus 10 shown in Fig. Both the surface temperature of the first roll 12A and the surface temperature of the second roll 12B were both set at 80 占 폚. The transport speed of the base film and the film having the protective film attached thereto was set at 1 m / min. Further, the line pressure applied to the film in the film thickness direction was set to 40 kN / m. The holding angle of the film with the base material and the protective film to the first roll 12A is 80 DEG.

The base film after the pressing and the protective film-adhering film were peeled off using a rectangular adhesive tape so that the average film thickness of the film after peeling off the protective film was 132 μm. Also, a heat resistance is 0.122 (℃ / W), the density of the first embodiment attached to a copper foil produced in the same manner as in heat conductive sheet obtained from the film after the pressing is 2.24 g / cm ^3. The specific heat of the heat-conductive sheet after the removal of the copper foil was 0.87 J / (g · K). The thermal diffusivity was 5.55 mm ² / s. As a result, the thermal conductivity was found to be 10.8 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 2.1 kV.

(Comparative Example 4)

In this comparative example, the same film as that of the film of Example 10 and the film 7 with the protective film was used.

Two 100 mm x 100 mm sizes were cut from the substrate and the base film attachment films 3A and 3B after the protective film 6 was peeled from the protective film attachment film 7 and two films were faced to each other with a flat plate press And the film was laminated to obtain the substrate laminated film 5 after the pressing. The conditions of the flat press at that time were a temperature of 150 占 폚, a pressure of 12 MPa, and a time of 1 minute under vacuum (15 mmHg (2.0 kPa) or less).

Only the film laminate 4 was peeled off from the substrate laminated film 5 after pressurization using a rectangular adhesive tape. The average film thickness of the film laminate 4 was 191 탆. As described above, since the average film thickness of the film was 118 占 퐉, the film thickness decreasing rate from the equation (2) was 79%.

Using the film laminate 4 obtained as described above, the copper foil was affixed with a flat plate press in the same manner as in Example 1 to obtain a heat conductive sheet with a copper foil. The obtained heat conductive sheet had a thermal resistance of 0.153 (캜 / W), a film thickness of 188 탆, a density of 2.33 g / cm ³ and a specific heat of 0.88 J / (g · K). The thermal diffusivity was 6.00 mm ² / s. As a result, the thermal conductivity was found to be 12.3 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 5.1 kV.

(Comparative Example 5)

When the materials weighed in the formulation shown in Example 10 were mixed into a ball mill, a varnish was prepared without adding 1 part by mass of cyclohexanone for the purpose of viscosity adjustment. As a result, a varnish of a solid content of 78 mass%, a viscosity of 3.5 Pa 占 퐏 (in a thermostat set at 25 占 폚 and a rotation speed of 5 min- ¹ (rotation / minute)) was obtained.

Next, the varnish was applied to a substrate. Polyethylene terephthalate (Purex A53, manufactured by DAIZIN CO., LTD.) Was used as a substrate. The substrate width was 400 mm, and the coating width was 350 mm. The coating was performed with a comma coater, and the coating gap was set to 350 m and the conveying speed was set to 0.5 m / min. The coated sheet was placed in a drying oven and dried at a temperature of 120 캜 for 10 minutes to obtain a film having a thickness of 140 탆 on the substrate. A sample of 5 cm x 5 cm in size was cut out from the dried film and dried at 180 DEG C for 1 hour under normal pressure. The mass was measured by a precision balance to calculate the residual volatile content as a rate of decrease from the mass of the film before the drying treatment did. The residual volatile content of the obtained film was 1.0% by mass. On the coated side of the obtained film, polyethylene terephthalate (Purex A53, manufactured by DAIZIN CO., LTD.) Was stuck as a protective film.

A sheet having a size of 100 mm x 100 mm was cut out from the obtained base material and the film having the protective film attached thereto and one film having the base material and the protective film adhered to each other in a vacuum (15 mmHg or less) The pressure was 12 MPa, and the pressure was 1 minute.

The base material after the pressing and the protective film-adhering film were peeled off using a rectangular adhesive tape to obtain only the film. The average film thickness of the obtained pressured film was 131 μm. The heat resistance of the thermally conductive sheet produced from this film was 0.126 (캜 / W), the density was 2.28 g / cm ³ , and the specific heat was 0.87 J / (g · K). The thermal diffusivity was 5.23 mm ² / s. As a result, the thermal conductivity was found to be 10.4 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 1.7 kV.

(Comparative Example 6)

The base material prepared in Comparative Example 5 and the film to which the protective film was adhered were pressed in the film thickness direction by the production apparatus 10 shown in Fig. Both the surface temperature of the first roll 12A and the surface temperature of the second roll 12B were both set at 80 占 폚. The transporting speed of the film was set at 1 m / min. In addition, the line pressure applied to the substrate-attached film by the first roll 12A and the second roll 12B in the film thickness direction was set at 40 kN / m. The holding angle of the base material-adhering film with respect to the first roll 12A is 80 DEG.

The average film thickness of the substrate-adhered film was 135 탆. The obtained heat-conductive sheet had a heat resistance of 0.121 (캜 / W), a density of 2.24 g / cm ³ , and a specific heat of 0.88 J / (g · K). The thermal diffusivity was 5.64 mm ² / s. As a result, the thermal conductivity was found to be 11.1 W / (m · K). On the other hand, the dielectric strength of the heat conductive sheet was 1.9 kV.

In all cases of Examples 1 to 10 and Comparative Examples 1 to 6, the interface between the copper foil and the film laminate of the copper foil-bonded heat conductive sheet was free from peeling and good in adhesion.

The results of the above Examples and Comparative Examples are summarized in Tables 1 to 3.

In Tables 1 to 3, "-" means that there is no value corresponding to the item.

As shown in Comparative Example 1 and Comparative Example 4, when a flat plate press was used as a means for applying pressure in the film thickness direction of two films, the heat resistance and the thermal conductivity were good. However, The result was low. On the other hand, as shown in Comparative Example 3 and Comparative Example 6, even when a roll is used as a means for applying pressure in the film thickness direction, when one film is used, Compared with the case where the pressure is applied in the thickness direction, the withstand voltage is significantly inferior.

From the above results, it was found that, in a method of producing a thermally conductive sheet obtained by applying pressure in the film thickness direction of a film laminate in which two films are arranged facing each other, the pressure in the film thickness direction of the film laminate The method of manufacturing the heat conductive sheet of the present invention including the step

The disclosure of Japanese Patent Application No. 2012-082675 filed on March 30, 2012 is hereby incorporated by reference in its entirety.

All publications, patent applications, and technical specifications described in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, and technical specification were specifically and individually indicated to be incorporated by reference. do.

Claims (15)

At least a first base material-adhering film and a second base material-adhering film having a base material, a film containing thermally conductive particles and a thermosetting resin provided on the base material,
The first base film and the second base film are brought into contact with each other and placed between a pair of rolls of a first pair of rolls and a pair of second rolls arranged opposite to each other,
And a step of rotating the pair of first and second rolls to apply pressure in the thickness direction of the film and further carrying the first base-attached film and the second base- A method of manufacturing a thermally conductive sheet comprising a plurality of films,
Wherein when the first base material-adhering film and the second base material-adhering film are disposed between the pair of rolls, the first base material-adhering film and the second base material-adhering film are placed apart from each other, And the substrate side of the first base-affixed film is brought into contact with the outer circumferential surface of the first roll, and the base side of the second base-affixed film is brought into contact with the outer circumferential surface of the second roll Wherein the first base material-adhering film and the second base material-adhering film are guided and arranged between the pair of rolls. delete The film forming apparatus as claimed in claim 1, wherein the first roll and the second roll are cut in a plane perpendicular to the rotation axis of the first roll and the second roll, , A straight line connecting a point on the most upstream side in the rotational direction of the first roll and a center point of the first roll in a region where the first base material affixed film and the first roll contact each other is defined as a straight line A , A straight line connecting the point on the most upstream side in the rotational direction of the second roll and the center point of the second roll in a region where the second base material-adhering film and the second roll contact each other is a straight line B, At least one of the angle formed by the straight line A and the straight line C and the angle formed by the straight line B and the straight line C is 30 DEG to 135 DEG when the straight line connecting the center point of the first roll and the center point of the second roll is the straight line C. A method of manufacturing a heat conductive sheet. The film according to any one of claims 1 to 3, wherein, when the mass per unit area of the film is multiplied by the mass per unit area of the thermally conductive sheet equal to the film thickness designed value, Wherein the mass satisfies the following formula (1): " (1) "

(Wherein n represents an integer of 2 or more, which represents the number of sheets of the film). The method of producing a thermally conductive sheet according to any one of claims 1 to 3, wherein a residual volatile content of the film before being disposed between the first roll and the second roll is 0.3% by mass to 1.2% by mass of the total mass of the film . 4. The method of producing a thermally conductive sheet according to any one of claims 1 to 3, wherein surface temperatures of the first roll and the second roll are both 60 ° C to 110 ° C. The method of producing a thermally conductive sheet according to any one of claims 1 to 3, wherein the first base material-adhered film and the second base material-adhered film have a conveying speed of 0.01 m / min to 2 m / min. The method of producing a thermally conductive sheet according to any one of claims 1 to 3, wherein the linear pressure applied by the first roll and the second roll in the film thickness direction is 10 kN / m to 350 kN / m. 4. The method of producing a thermally conductive sheet according to any one of claims 1 to 3, wherein the film thickness reduction rate represented by the following formula (2) in the heat conduction sheet is 50% to 95%.

The film forming apparatus according to any one of claims 1 to 3, wherein the first base film-adhering film and the second base film-adhering film portion, which have passed between the rolls of the pair of the first roll and the second roll, Wherein the second roll is disposed between rolls of a pair of rolls constituting between rolls different from between rolls of the second roll, and pressure is applied in the film thickness direction of the film. The method of producing a thermally conductive sheet according to claim 1 or 3, wherein the thermosetting resin is a liquid epoxy resin. The method of producing a thermally conductive sheet according to any one of claims 1 to 3, wherein the thermally conductive particles comprise a filler having at least three different volume average particle diameters. A heat conductive sheet produced by the manufacturing method according to claim 1 or 3. A heat conductive sheet with a metal foil provided with a metal foil on the heat conductive sheet according to claim 13. A semiconductor device comprising the heat conductive sheet with a metal foil according to claim 14, wherein the semiconductor device is a power control unit or LED for mounting on a vehicle.

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