JP2013173889A - Adhesion heat radiation sheet, and method for increasing tenacity of adhesion heat radiation sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesion heat radiation sheet in which tenacity of a sheet shape is high, and that has excellent high-temperature adhesion.SOLUTION: An adhesion heat radiation sheet is such that a tensile modulus of a sheet is 10to 10Pa, a level difference of a part with the highest projection of a surface of the sheet and a part with the lowest recess is 10 μm to 100 μm, and an area that the projection occupies to an area of the sheet is 50 to 95%. The adhesion heat radiation sheet is desirably a multilayer sheet that includes a polyimide layer in a layer structure. It is desirable that a composition of the adhesion heat radiation sheet is 30-70 volume% of a resin, and 70-30 volume% of an inorganic powder. It is desirable that the inorganic powder is aluminum hydroxide or alumina.

Description

  The present invention relates to a heat dissipation sheet having adhesiveness.

With the recent high performance of electronic members, the heat generation density of the members has increased, and the necessity of a heat radiating material sheet has been increased in order to release this heat.
In the conventional technology, even if the heat-dissipating sheet is not sticky, or even if it is a heat-dissipating sheet to which adhesive has been applied, its adhesive strength is not sufficient, so it is necessary to use a separate screw to sandwich the heat-dissipating sheet. It took time and effort.

JP 2005-54006 A JP 2004-27039 A

  In view of the problems of the prior art, the present invention is to provide a pressure-sensitive heat-dissipating sheet having high sheet-like adhesive strength and having excellent high-temperature adhesiveness.

The present invention employs the following means in order to solve the above problems.
(1) The tensile modulus of the sheet is 10 ⁵ to 10 ⁸ Pa, the step between the highest part of the convex part on the surface of the sheet and the lowest part of the concave part is 10 μm or more and 100 μm or less, and with respect to the area of the sheet An adhesive heat-dissipating sheet in which the area occupied by the protrusions is 50% to 95%.
(2) The adhesive heat-radiating sheet according to (1), which is a multilayer sheet including a polyimide layer in a layer structure.
(3) The adhesive heat-radiating sheet according to (1) or (2), wherein the composition of the adhesive heat-radiating sheet is 30 to 70% by volume of resin and 70 to 30% by volume of inorganic powder.
(4) The adhesive heat-radiating sheet as described in (3) above, wherein the inorganic powder is aluminum hydroxide or alumina.
(5) The tensile modulus of the sheet is 10 ⁵ to 10 ⁸ Pa, the step between the highest part of the convex part on the surface of the sheet and the lowest part of the concave part is 10 μm or more and 100 μm or less, and the convex part with respect to the area of the sheet A method for increasing the adhesive strength of an adhesive heat-dissipating sheet by changing the occupied area from 50% to 95%.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive heat dissipation sheet which has high adhesive force and has the outstanding high temperature adhesiveness is obtained.

Single-layer product with a double-sided uneven surface shape of the adhesive heat dissipation sheet. Multi-layered product with double-sided uneven surface shape of adhesive heat dissipation sheet. Surface shape of adhesive heat dissipation sheet. High temperature shape retention and high temperature adhesion specimens. Transistor shape

The adhesive heat-radiating sheet of the present invention has a tensile elastic modulus of 10 ⁵ to 10 ⁸ Pa. If the tensile modulus is less than 10 ⁵ Pa, it is not preferable because it is too soft and the high-temperature adhesiveness decreases. If it is higher than 10 ⁸ Pa, it is hard, so that the adhesive strength is lowered, and the wetness of the adhesive interface is poor, which is not preferable. The tensile modulus is a tensile modulus at 25 ° C.

In the adhesive heat-dissipating sheet of the present invention, the level difference between the highest part of the convex part and the lowest part of the concave part on the surface of the continuous sheet is 10 μm or more and 100 μm or less.
If the level difference between the convex part and the concave part on the surface of the sheet is less than 10 μm, the air generated when the sheet is adhered is poor and the adhesion area is reduced, so that the adhesive strength is reduced. If the level difference between the convex part and the concave part on the surface of the sheet exceeds 100 μm, the level difference is too large, resulting in non-uniform adhesion and poor air escape, and a reduced adhesion area, resulting in a decrease in adhesive strength.

As for the adhesive heat-radiation sheet of this invention, the area which a convex part occupies with respect to the area of a sheet | seat is 50 to 95%.
If the area which a convex part occupies with respect to the area of an adhesive heat-radiation sheet is less than 50%, an adhesion area will become small and an adhesive heat-radiation sheet will peel easily. Moreover, since the adhesion area is too small, the thermal resistance value is increased, and the heat dissipation characteristics are deteriorated.
If the area occupied by the protrusions exceeds 95% of the area of the adhesive heat-dissipating sheet, the air generated in the center of the adhesive surface remains adhering during bonding, and there is no escape space for the air. This is not preferable because the non-adhered portion of the adhesive increases, the thermal resistance value of the bonded surface increases, and the heat dissipation characteristics deteriorate.
Note that the area occupied by the convex portions of the sheet is a horizontal plane in which the sheet is horizontally installed and a horizontal line is drawn in the sheet surface direction based on the average thickness of the sheets at both ends of the sheet. Let the part which protruded from the horizontal surface be the area which a convex part occupies.

The shape of the surface of the adhesive heat-radiating sheet is uneven.
The shape of the surface of the sheet may be any shape such as a quadrilateral, a rectangle, a rhombus, a parallelogram, or a round shape.
The shape of the recess may be U-shaped, square, triangular, or trapezoidal, and it is preferable that grooves that are continuously connected and have a lattice shape are formed so as to surround the protrusion. Or it is preferable that the groove | channel which is in the shape of a line or curved line is formed continuously so that two sides of a convex part may be inserted | pinched.
For example, the shape of a convex part is a rhombus, the shape of a recessed part is trapezoid, and the shape with a grid | lattice-like induction groove is preferable.
The guide groove is a lattice-shaped or line-shaped recess formed continuously in the sheet.

For the processing of the adhesive heat-radiating sheet, for example, a PET film embossed on the release liner film of the adhesive heat-dissipating material can be used in order to make the surface uneven.
Examples of the concavo-convex processing for providing the concavo-convex include mat processing, sand blast processing, plasma processing, embossing, etc. whose surface has been roughened in advance.
Of these, embossing is desirable.

Furthermore, it is preferable to apply an uneven heat treatment to the release liner while laminating the release liner PET between the embossed rolls and to apply an adhesive heat dissipation material.
In addition to this, if extrusion molding is used, the inner surface of the press or injection mold is embossed when the die base shape is processed, or when an adhesive heat-dissipating sheet is formed by press molding or injection molding, in order to give irregularities to the die lip shape. Further, drawing and blasting are also preferable, and one or more of these may be used for processing. It is also preferable to use a transfer sheet and insert it into a mold to perform sand molding or insert molding without any particular limitation.

Adhesive heat dissipation material with uneven surface is less affected by adherence flatness, roughness, swell, etc. than adhesive heat dissipation material with smooth surface, and adhesive heat dissipation material follows adherend to adhere. Good properties. In particular, the shape of the recess working shape having a lattice shape in the form of a guide groove is easy to adhere because the air escape is good. In addition, the thermal resistance is reduced and the heat dissipation is improved.
If the area occupied by the guide groove exceeds 50% with respect to the sheet area, the adhesive area of the pressure-sensitive adhesive sheet is reduced, the thermal resistance is increased, the heat dissipation characteristics are lowered, and the adhesive force is reduced, so that it is easily peeled off. Therefore, it is not preferable.
Moreover, it is preferable to make it adhere | attach on the sticking conditions of an adhesive heat-radiation sheet with the pressure of 10 N / cm < ² > or more.

When the area ratio of adhesion to the adherend is less than 50%, the heat-dissipating sheet is easily peeled off, the thermal resistance value is increased, and the heat-dissipation characteristics are deteriorated. A thermal resistance value of 80% or more is preferable because the thermal resistance value becomes small and the heat dissipation characteristics are improved.
When the thickness of the sheet exceeds 500 μm, the thermal resistance value is large and the heat dissipation characteristics are reduced, and this is not preferable. When the thickness is less than 50 μm, the sheet is difficult to handle. The sheet thickness is preferably in the range of 50 μm to 500 μm because the handleability, the workability of the sheet, and the heat dissipation characteristics are good.

The configuration of the adhesive heat-dissipating sheet is a three-layer structure in which the release liner film base material 1 (upper), the base material 1 (lower) are placed in the outermost layer, and the adhesive heat-dissipating sheet 2 enters (middle) in this film. is there. For example, a polyimide film may be inserted between the adhesive heat-dissipating materials to provide insulation, and a five-layer structure may be used. The adhesive heat-dissipating sheet is peeled off depending on the application, regardless of whether it is a single layer or multiple layers. A laminated structure between liners is common.
In particular, when a polyimide film is inserted, the polyimide film may be any one obtained by corona treatment, sandblast treatment, or plasma treatment.
A multilayer structure in which a polyimide film layer is inserted is particularly preferable in terms of improving the insulation characteristics, and may not be inserted if the product has no particular problem with insulation.
Moreover, when roll-rolling, an uneven | corrugated process may be carried out on a peeling liner and an adhesive heat dissipation material interface, and the opposite surface may be made into a smooth surface structure, and it is also useful to change a surface shape according to the structure of a to-be-adhered body. In the case of a multilayer structure, the thickness of the adhesive heat dissipating material on the upper and lower surfaces can be changed, and can be varied in order to further improve the adhesion of the adherend.

Examples of the resin in the present invention include an acrylic resin and a silicone resin.
An acrylic resin is resin which has the following (a) and / or (b) as a main component.
(A) an acrylate or methacrylate having an alkyl group having 2 to 12 carbon atoms,
(B) an acrylic monomer represented by the formula (1),

_{CH 2 CR 1 CO- (OR 2} ) n -OR 3 formula (1)

In the formula (1), R1 represents hydrogen or a methyl group. R2 represents an alkylene group such as an ethylene group, a propylene group, or a butylene group, R3 represents hydrogen, an alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted phenyl group, and n represents an integer of 1 to 12.
As an example of the component (a), the acrylate or methacrylate having an alkyl group having 2 to 12 carbon atoms is an acrylic acid alkyl ester or methacrylic acid alkyl ester having 2 to 12 carbon atoms.
Examples of the component (b) include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-methoxyethyl acrylate, ethoxyethyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, and nonylphenoxyethyl acrylate. , 2-ethylhexyl carbitol acrylate, diethylene glycol monoacrylate, triethylene glycol monoacrylate, polyethylene glycol monoacrylate with ethylene glycol unit repeat number of 12 or less, methoxypolyethylene glycol monoacrylate with ethylene glycol unit repeat number of 12 or less, ethylene glycol unit Ethoxypolyethyleneglycol with 12 or fewer repeats Monoacrylate, phenoxy polyethylene glycol monoacrylate with ethylene glycol unit repeat number of 12 or less, polypropylene glycol monoacrylate with propylene glycol unit repeat number of 12 or less, methoxypolypropylene glycol monoacrylate with propylene glycol unit repeat number of 12 or less, propylene glycol unit Ethoxypolypropylene glycol monoacrylate having a repeating number of 12 or less, Phenoxy polypropylene glycol monoacrylate having a repeating number of propylene glycol units of 12 or less, Polybutylene glycol monoacrylate having a repeating number of butylene glycol units of 12 or less, Repeating number of ethylene glycol units of 12 or less The polyethylene grease Over mono methacrylate, propylene glycol unit number of repetitions 12 following polypropylene glycol monomethacrylate, butylene glycol unit number of repetitions 12 following polybutylene glycol monomethacrylate, and the like, not limited to this.

The acrylic resin can be cured by a photopolymerization reaction, a heat curing reaction, or the like.
When the acrylic resin is cured by a photopolymerization reaction, it is preferable from the viewpoint of curing reaction control to use a photopolymerization reaction using a photopolymerization initiator. As photopolymerization initiators, benzophenone, p-methoxybenzophenone, 4,4-bisdimethylaminobenzophenone, xanthone, thioxanthone, chlorothioxanthone, m-chloroacetone, propiophenone, anthraquinone, benzoin methyl ether, benzoin ethyl ether, Benzoisopropyl ether, benzoin butyl ether, benzyl, 2,2-dimethoxy-1,2-diphenylethane-1-one, acetophenone, 2,2-diethoxyacetophenone, 2-hydroxy-2,2-dimethylacetophenone, 1-hydroxy -Cyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one 1- [4- (2-hydroxy) -phenyl] -2-hydroxy-2-methyl-1-prop 1-one and the like, but not limited to. However, since a photoinitiator having an absorption wavelength for visible light lacks the storage stability of the paint, it is preferable to use benzophenone and 1-hydroxy-cyclohexyl-phenyl ketone which do not absorb visible light. These photoinitiators may be used alone or in combination.

When the acrylic resin is cured by a heat curing reaction, a heat decomposable polymerization initiator such as an organic peroxide or an azo compound is used as a heat curing initiator. Organic peroxides include diacyl peroxides such as lauroyl peroxide and benzoyl peroxide, t-butylperoxy-3,5,5-trimethylhexanoate, cumylperoxyneodecanoate, hexylperoxybiba Alkyl peroxyesters such as rate, t-butyl peroxyisobutyrate, t-butyl peroxybivalate, t-butyl peroxyacetate, t-butyl peroxybenzoate, tertiary butyl peroxy-2-ethylhexanate Diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, dinormalpropyl peroxydicarbonate, bis (4-tertiarybutylcyclohexyl) peroxydicarbonate, di-2-ethoxye Peroxydicarbonates such as ruperoxydicarbonate, dimethoxyisopropylperoxydicarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate and diallylperoxydicarbonate, t-butylperoxyisopropylcarbonate, etc. Peroxyketals such as peroxycarbonates, di-t-butylperoxycyclohexane, di- (t-butylperoxy) butane, dicumyl peroxide, t-butylcumyl peroxide, di-t-butyl Dialkyl peroxides such as peroxides, hydroperoxides such as cumene hydroperoxide and tetramethylbutyl hydroperoxide, ketone peroxides such as ketone peroxide and cyclohexanone peroxide Kisaido, and the like can be mentioned.

The curing accelerator can be used as long as it is a known curing accelerator that reacts with the thermal decomposition polymerization initiator to generate radicals. Typical curing accelerators include, for example, tertiary amines, thiourea derivatives, transition metal salts and the like. Examples of the tertiary amine include triethylamine, tripropylamine, tributylamine, and N, N-dimethyl-p-toluidine. Examples of the thiourea derivative include 2-mercaptobenzimidazole, methylthiourea, sibutylthiourea, tetramethylthiourea, and ethylenethiourea. Examples of the transition metal salt include cobalt naphthenate, copper naphthenate, and vanadyl acetylacetonate.

When an acrylic resin is used, a copolymerizable crosslinking component such as a known polymerizable compound, a known polyfunctional vinyl compound, a polyfunctional acrylate, or a polyfunctional allyl compound can be included.

The silicone resin may be linear or branched as long as it is an organopolysiloxane and has at least two alkenyl groups directly bonded to silicon atoms in one molecule. This organopolysiloxane may be one type or a mixture of two or more different viscosities. Examples of the alkenyl group include a vinyl group, an allyl group, a 1-butenyl group, and a 1-hexenyl group. In general, a vinyl group is preferable from the viewpoint of ease of synthesis and cost. Other organic groups bonded to the silicon atom include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, hexyl group and dodecyl group, aryl groups such as phenyl group, 2-phenylethyl group, 2-phenylpropylene. And aralkyl groups such as ruthenium groups, and substituted hydrocarbon groups such as chloromethyl group and 3,3,3, -trifluoropropyl group. Of these, a methyl group is preferable.
The alkenyl group bonded to the silicon atom may be present at any end or in the middle of the molecular chain of the organopolysiloxane.

A known additive can be added to the resin in an arbitrary amount. Examples of the additive include various additives for controlling viscosity and viscosity, other modifiers, anti-aging agents, heat stabilizers, colorants and the like.

Examples of the inorganic powder used in the present invention include metal oxides such as alumina and titanium dioxide, nitrides such as aluminum nitride, boron nitride, and silicon nitride, silicon carbide, and aluminum hydroxide. These may be used alone or in combination of several kinds. can do. Aluminum hydroxide is preferable in consideration of flame retardancy, and alumina is preferable in consideration of thermal conductivity.

The blending of the resin and the inorganic powder is preferably 30 to 70% by volume of the resin and 70 to 30 volume of the inorganic powder. If the resin material is less than 30% by volume, the adhesive strength may be reduced, and if it exceeds 70% by volume, the heat dissipation may be reduced.

The mixing method of the resin and the inorganic powder is not particularly limited, but in the case of a small amount, manual mixing is also possible, but a universal mixer, planetary mixer, hybrid mixer, Henschel mixer, kneader, ball mill, mixing A general mixer such as a roll is used.
In mixing, various solvents such as water, toluene, alcohol and the like can be added to obtain a mixture suitable for each molding method.

  As a method for processing a resin composition comprising a resin and an inorganic powder into a sheet, conventionally known methods such as a coater method, a doctor blade method, an extrusion molding method, an injection molding method, and a press molding method are used. be able to. In addition, as a base material reinforcement method, when the sheet | seat of this invention has double-sided adhesiveness, a sheet | seat and a base material can be laminated | stacked using well-known lamination methods, such as a normal laminating method and a press method. Although possible, these reinforcing base materials may be used directly as a base material to be used in the coater method or the like.

The method for producing an adhesive heat-dissipating sheet includes a step of preparing an adhesive heat-dissipating sheet and a step of applying or molding the composition, and a concavity and convexity processing step is provided on a continuous surface of the surface of the adhesive heat-dissipating material. Further, the step of curing the adhesive heat radiation material sheet includes a curing step such as ultraviolet curing or heat curing.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.
(Examples 1-4, 6-19, 22-33: Acrylic resin UV curable)
Each material described in each example in Table 1 was mixed with a self-revolving mixer to prepare a slurry mixture. The slurry was sandwiched between two release liner PET films, laminated, and then cured by irradiation with ultraviolet rays to obtain a sheet-like molded body. As the release liner film, an embossed PET film was used. As the surface shape of the adhesive heat-dissipating sheet, the shape of the convex portion was a rhombus, the shape of the concave portion was a trapezoidal shape and had a lattice-shaped guide groove.
(Example 5: Acrylic resin heat curing type)
Each material described in Example 5 in Table 1 was mixed with a self-revolving mixer to prepare a slurry mixture. The slurry was sandwiched between release liner PET films, laminated and then heat-cured at 120 ° C. for 20 minutes to obtain a sheet-like molded body. As the release liner film, an embossed PET film was used. As the surface shape of the adhesive heat-dissipating sheet, the shape of the convex portion was a rhombus, the shape of the concave portion was a trapezoidal shape and had a lattice-shaped guide groove.
(Examples 20 to 21: silicone resin)
Each material described in Examples 20 to 21 in Table 1 was mixed with a self-revolving mixer to prepare a slurry mixture. The slurry was sandwiched between release liner PET films, laminated and then heat-cured at 120 ° C. for 20 minutes to obtain a sheet-like molded body. As the release liner film, an embossed PET film was used. As the surface shape of the adhesive heat-dissipating sheet, the shape of the convex portion was a rhombus, the shape of the concave portion was a trapezoidal shape and had a lattice-shaped guide groove.

(Comparative Examples 1-6)
Each material described in Comparative Examples 1 to 6 in Table 2 was mixed with a self-revolving mixer to prepare a slurry-like mixture. The slurry was sandwiched between two release liner PET films, laminated, and then cured by irradiation with ultraviolet rays to obtain a sheet-like molded body.
As the release liner film, an embossed PET film was used. As the surface shape of the adhesive heat-dissipating sheet, the shape of the convex portion was a rhombus, the shape of the concave portion was a trapezoidal shape and had a lattice-shaped guide groove.
In both Examples and Comparative Examples, the surface shape of the adhesive heat-dissipating sheet is a double-sided uneven type. The Examples evaluated single-layer products using an adhesive heat-dissipating sheet and multilayer products using an adhesive heat-dissipating sheet and a polyimide film.
(See Figs. 1, 2, and 3)

The materials used in Examples and Comparative Examples are shown below.
1) AR53L product name (acrylic rubber, manufactured by Nippon Zeon)
2) 2-EHA trade name (2-ethylhexyl acrylate acrylate, manufactured by Toagosei Co., Ltd.)
3) Acrylic acid, manufactured by Toagosei Co., Ltd. 4) UC203, trade name (methacryloyl-modified liquid isoprene rubber, manufactured by Kuraray Co., Ltd.)
5) DMDO product name (1,8-dimercapto-3,6-dioxaoctane, manufactured by Maruzen Chemical Co., Ltd.)
6) Irgacure 651 trade name (benzophenone, hydroxycyclohexyl phenyl ketone mixture, manufactured by Ciba Specialty Chemicals)
7) Perbutyl Z Trade name (t-butyl peroxybenzoate, manufactured by NOF Corporation)
8) H-32 trade name (aluminum hydroxide, Showa Denko)
9) HP-360 trade name (aluminum hydroxide, Showa Denko)
10) DAW45S product name (spherical alumina manufactured by Denki Kagaku Kogyo Co., Ltd.)
11) SE-1885 trade name (SE-1885, manufactured by Silicone Toray Dow Corning) 12) RD-1 trade name (Si-H siloxane, manufactured by Toray Dow Corning)
13) Substrate Aluminum radiating fin
Material (1) # 1050
Material (2) Nickel plating (# 1051 material)
14) Polyimide film Kapton film (manufactured by Toray DuPont)
15) Push-pull gauge FB50N (made by Imada)
16) Transistor K3432 TO-220 type (manufactured by NEC)
17) Slide glass (Matsunami)
18) Torque wrench N20DPSK (KANON)

The adhesion method with the glass of an adhesive heat-radiation sheet is demonstrated.
An adhesive heat dissipation sheet was attached to the glass surface, and the transistor was placed on the sheet. In Examples and Comparative Examples, a push-pull gauge was used at a pressure of 10 N / cm ² , and pressure was applied for 3 seconds for pasting. The surface of the glass surface was observed through the glass, and the area of the bonded portion excluding the air biting portion with respect to the transistor bonded area was evaluated with a planimeter.

The high temperature shape retention will be described.
The adhesive heat radiation sheet was attached to the following adherend and evaluated.
The adhesive heat-dissipating sheet was affixed to the heat dissipation fin of (1) aluminum # 1050 material, (2) Ni plating (aluminum) material aluminum material. Further, the release liner substrate was peeled off, and the transistor was placed thereon, and the transistor (FIG. 5) was attached by applying pressure vertically for 3 seconds with a push-pull gauge fixed to a vertical pressure jig at a pressure of 10 N / cm ² . . The transistor was energized and the transistor temperature was raised to 120 ° C. The presence or absence of the transistor holding or dropping was evaluated.
(See Figure 4)

The high-temperature adhesion evaluation confirmed whether or not the transistor dropped (n = 3).
The case where the transistor temperature reached a predetermined temperature and was held for 15 minutes was evaluated as ◯, and the case where the transistor dropped or shifted was evaluated as x. When all of n = 3 are held, ○ is marked with × when one drop or displacement occurs.
It was evaluated that the transistor continued to be energized with the transistor on the bottom and the fin on the top, and the fin was air cooled. As the transistor, a TO-220 type transistor manufactured by NEC was used.
Then, after confirming that the transistor was at room temperature, the transistor was rotated with a torque wrench, and the area of the bonded portion excluding the air biting portion with respect to the transistor bonded area after the transistor was peeled off was evaluated with a planimeter.
The shape of the adhesive heat-dissipating sheet used was a 20 mm × 20 mm square. The torque wrench was a torque wrench (20DPSK) manufactured by KANON, and the transistor was directly added with a tip width of 10.5 mm, and the torque wrench was rotated at 45 ° for 3 seconds.
(See Figure 4)

The torque adhesive force will be described.
The transistor was pressurized for 3 seconds at a pressure of 10 N / cm ² through an adhesive heat-dissipating sheet, and the transistor was attached to the adherend and cured at room temperature of 25 ° C. for 10 minutes. The cured transistor was rotated with a torque wrench, and the load N of the torque wrench when the transistor was detached from the adherend was measured. As the transistor, a TO-220 type transistor manufactured by NEC was used.
The shape of the pressure-sensitive adhesive sheet used is a 20 mm × 20 mm square. The torque wrench was a torque wrench (20DPSK) manufactured by KANON, and the transistor was directly added with a tip width of 10.5 mm, and the torque wrench was rotated at 45 ° for 3 seconds.

The adhesive strength test method will be described.
First, a 20 mm × 20 mm square sample is prepared for the adhesive heat-dissipating sheet to be tested. This sample is affixed to an AL test piece (1050 material, 25 mm × 80 mm). After pasting this AL test piece on one side and pressing with a 2 kg roller, it is cured for 30 minutes at room temperature 25 ° C. Thereafter, the adhesive strength (N / 25 mm) was measured by pulling the AL test pieces on both sides with a tensile tester (Tensilon, manufactured by A & D). Tensile speed is 5 mm / min.

A thermal resistance measurement method will be described.
The thermal resistance was measured by the method shown below. 4. Adhesive heat radiation sheet measurement sample (20mm x 20mm square) attached as shown in Fig. 4 is sandwiched between transistor temperature T1 and heat radiation fin upper part T2, from the top with a pressure of 10N / cm ² for 3 seconds with push-pull gauge Pressurized. The power was adjusted so that the temperature of the transistor was 120 ° C., the temperature difference between the samples T1 / T2 at that time was measured, and the thermal resistance was calculated from the following equation (2).

Thermal resistance (℃ / W) = Temperature difference (℃) / Applied voltage (W) Equation (2)

The adhesive heat-dissipating sheet shown in the examples had high adhesive strength and exhibited excellent high-temperature adhesiveness. On the other hand, the comparative example was inferior to adhesive force and high temperature adhesiveness.

The adhesive heat-dissipating sheet of the present invention is expected to be applied not only to electronic parts but also in all fields where heat dissipation and adhesiveness are required.

DESCRIPTION OF SYMBOLS 1 Release liner PET film 2 Adhesive heat dissipation sheet 3 Surface unevenness process 4 Polyimide film 5 The shape of a convex part is a rhombus 6 The shape of a concave part is a trapezoid, and it is a grid | lattice-like induction groove 7 Cooling fin 8 Adhesive heat dissipation sheet 9 Transistor 10 Transistor temperature sensor 11 Cooling fin temperature sensor

Claims (5)

The tensile modulus of the sheet is 10 ⁵ to 10 ⁸ Pa, the step between the highest part of the convex part on the surface of the sheet and the lowest part of the concave part is 10 μm or more and 100 μm or less, and the convex part with respect to the area of the sheet Adhesive heat dissipation sheet with an area occupied by 50% to 95%. The adhesive heat-radiating sheet according to claim 1, which is a multilayer sheet including a polyimide layer in a layer structure. The adhesive heat-radiating sheet according to claim 1 or 2, wherein the composition of the adhesive heat-radiating sheet is 30 to 70% by volume of resin and 70 to 30% by volume of inorganic powder. The adhesive heat-radiating sheet according to claim 3, wherein the inorganic powder is aluminum hydroxide or alumina. The tensile modulus of the sheet is 10 ⁵ to 10 ⁸ Pa, the step between the highest part of the convex part on the surface of the sheet and the lowest part of the concave part is 10 μm or more and 100 μm or less, and the area occupied by the convex part with respect to the area of the sheet A method for increasing the adhesive strength of an adhesive heat-dissipating sheet by adjusting the amount from 50% to 95%.