JPH10330692A - Thermally conductive pressure sensitive adhesives and their adhesive sheets - Google Patents

Abstract

[57] [Abstract] [Problem] Excellent in thermal conductivity and adhesiveness, especially high adhesive strength at high temperature (heat-resistant shear holding force), excellent in adhesive stability, and satisfactory in versatility Provide heat conductive pressure-sensitive adhesive sheets. SOLUTION: On one or both surfaces of a base material, a) a main monomer 70 to 100 containing, as a main component, an alkyl (meth) acrylate having an average of 2 to 14 carbon atoms in an alkyl group;
% By weight and a copolymerizable monomer 30 having a polar group in the molecule.
To 0% by weight of a monomer (or a partial polymer thereof)
100 parts by weight, b) 0.01 to 5 parts by weight of a photopolymerization initiator,
c) a photopolymer of a composition comprising 10 to 300 parts by weight of a thermally conductive filler and d) 0.001 to 3 parts by weight of a reactive surfactant having a radically polymerizable carbon-carbon double bond in the molecule. A heat-conductive pressure-sensitive adhesive sheet in the form of a sheet or tape is provided by providing a layer of a heat-conductive pressure-sensitive adhesive made of the following.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to fixing electronic parts,
In particular, fixing of electronic parts and heat radiation members, and other building materials,
Thermal conductivity with excellent thermal conductivity and adhesiveness, especially for high-temperature adhesiveness (heat-resistant shear holding force), used for fixing members in various fields such as vehicles, aircraft, and ships. The present invention relates to a pressure-sensitive adhesive and an adhesive sheet in the form of a sheet or tape.

[0002]

2. Description of the Related Art Conventionally, in electronic parts such as a hybrid package, a multi-module, and a plastic or metal hermetically sealed integrated circuit, the amount of heat generated has increased due to the high integration of an IC circuit. Since there is a possibility that the electronic component may cause a functional failure due to a rise in temperature, measures have been taken to prevent the above functional failure by attaching a heat radiating member such as a heat sink to the electronic component.

As a method of attaching a heat radiation member to an electronic component, there is known a method of using an adhesive obtained by adding aluminum powder or the like to a composition containing a polymerizable acrylate monomer and a free radical initiator (US). Patent 4,72
2,960). However, in this method, after applying the adhesive to one or both of the electronic component and the heat radiating member, it is necessary to use a primer or block oxygen to perform a curing treatment. There has been a problem that the manufacturing efficiency of the electronic device is poor, such as requiring labor and temporarily fixing the adherend until it is cured.

In order to avoid such a problem, for example, a method using a pressure-sensitive adhesive tape in which silver particles having a particle diameter larger than the thickness of the adhesive layer is contained (US Pat.
No. 06,962) or a pressure-sensitive adhesive tape in which thermally conductive electrically insulating particles are randomly dispersed in an acrylic polymer (JP-A-6-88061, EP-566).
093-A1) has been proposed.

[0005] These proposed pressure-sensitive adhesive tapes are interposed between an electronic component and a heat radiating member, and the two are bonded and fixed by utilizing the pressure-sensitive adhesive property. There are essentially no problems such as requiring many hours and labor. However, these proposed pressure-sensitive adhesive tapes are inferior in stability of the heat-conductive pressure-sensitive adhesive itself, and the viscosity is extremely increased during or after the preparation of the adhesive, impairing the flowability, and the handling property is particularly high. The workability deteriorated, and there was a problem that not only the thickness accuracy was not obtained when the tape was formed, but also the tape could not be formed when the tape was severe.

Therefore, the present inventors have found that a thermal conductive filler having the same polarity as the above-mentioned polar group is blended with the acrylic copolymer having a polar group to thereby improve the thermal conductivity. A heat-conductive pressure-sensitive adhesive with excellent stability that does not show a sharp increase in viscosity during or after preparation of the adhesive and does not deteriorate handling properties, especially coating workability. And the fact that adhesive sheets thereof can be obtained, and this has already been proposed as an invention according to Japanese Patent Application No. 8-3237141.

[0007]

However, in the above-mentioned heat-conductive pressure-sensitive adhesives and their adhesive sheets, the types of heat-conductive fillers that can be blended with an acrylic copolymer having a polar group are disclosed. However, there is a drawback in that the versatility is inferior, because it is limited to a specific one.

In view of such circumstances, the present invention provides heat conduction for fixing electronic components and heat radiating members, and for fixing members in various fields such as construction materials, vehicles, aircraft, and ships. As a pressure-sensitive adhesive and its adhesive sheets, it has excellent thermal conductivity and adhesiveness, and particularly has a large adhesive force (heat-resistant shear holding force) at high temperatures, and a sharp viscosity during and after the preparation of the adhesive. An object of the present invention is to provide a material which has no increase, has excellent stability, and is satisfactory in terms of versatility.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above object, and as a result, when synthesizing an acrylic polymer, a photopolymerization initiator and a photopolymerization initiator were added to the monomer or partial polymer. When a specific surfactant is blended together with a thermally conductive filler and this composition is applied to a tape base material and then irradiated with ultraviolet rays and photopolymerized, it has excellent thermal conductivity and adhesiveness. Adhesive strength under high temperature (heat-shear holding power) is large, and no drastic increase in viscosity is observed during or after the preparation of the above composition, so that handling properties, especially coating workability, do not deteriorate. It is possible to obtain a heat-conductive pressure-sensitive adhesive with excellent stability and its adhesive sheets, and in this case, there is no particular limitation on the monomer composition of the acrylic polymer and the type of the heat-conductive filler. , Can be used to select the desired one, versatility To know that you can fully satisfactory in terms,
The present invention has been completed.

That is, according to the present invention, a) 70 to 100% by weight of a main monomer mainly composed of an alkyl (meth) acrylate having an average of 2 to 14 carbon atoms in an alkyl group;
And a copolymerizable monomer having a polar group in the molecule of 30 to 0% by weight (or a partially polymerized product thereof) 100
Parts by weight, b) 0.01 to 5 parts by weight of a photopolymerization initiator, c) 10 to 300 parts by weight of a thermally conductive filler, d) a reactive interface having a radically polymerizable carbon-carbon double bond in the molecule. A thermally conductive pressure-sensitive adhesive comprising a photopolymer of a composition containing 0.001 to 3 parts by weight of an activator (claim 1,
(2) and an adhesive sheet (claim 3), wherein a layer of the heat conductive pressure-sensitive adhesive is provided on one or both surfaces of the substrate.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the composition of the present invention, the monomer of component a (or a partially polymerized product thereof) has, as a main monomer, an alkyl group having an average of 2 to 14 carbon atoms ( Alkyl (meth) acrylate is used as a main component. The term “main component” means that, in addition to the above ester, other monomers such as styrene, vinyl chloride, and vinyl acetate may be contained at a ratio of usually 30% by weight or less in the main monomer. I do.

The above alkyl group has an average of 2 to 14 carbon atoms.
Examples of the alkyl (meth) acrylate include butyl (meth) acrylate, isononyl (meth) acrylate, isooctyl (meth) acrylate, and (meth) acrylate.
2-ethylhexyl acrylate and the like can be mentioned. The main monomer having these as main components is 70 to 70% in the monomer mixture.
It is used in a proportion of 100% by weight, preferably 90 to 99% by weight. If it is less than 70% by weight, the adhesive performance as an acrylic polymer is impaired.

In addition to the above main monomers, copolymerizable monomers having a polar group in the molecule can be used. This copolymerizable monomer contributes to an improvement in the adhesive force (heat-resistant shear holding force) to a high-polarity electronic component at a high temperature, and is useful for increasing the adhesive fixing force between the electronic component and the heat dissipation member. Yes, it is used in a proportion of 30 to 0% by weight, preferably 10 to 1% by weight in the monomer mixture.

The above copolymerizable monomers include (meth) acrylic acid, maleic acid, caprolactan-modified (meth) acrylate, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyl Carboxyl group-containing monomers such as oxyethyl phthalic acid, caprolactan-modified hydroxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy Hydroxyl-containing monomers such as hexyl (meth) acrylate, (meth) acrylamide, N-vinylpyrrolidone,
Nitrogen-containing monomers such as (meth) acryloylmorpholin.

In the composition of the present invention, benzoin ethers such as benzoin methyl ether and benzoin isopropyl ether,
Substituted benzoin ethers such as anisoin methyl ether; substituted acetophenones such as 2,2-diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone; 2-methyl-2- Substituted-α-ketoles such as hydroxypropiophenone, aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride,
Examples include photoactive oximes such as 1-phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime.

These photopolymerization initiators are used in an amount of 0.1 parts by weight based on 100 parts by weight of the monomer (a) (or a partially polymerized product thereof).
It is used in an amount of from 0.01 to 5 parts by weight, preferably from 0.05 to 1 part by weight. When the amount is less than 0.01 part by weight, a large amount of monomer remains in the photopolymer, and when the amount is more than 5 parts by weight, the molecular weight of the photopolymer decreases and the cohesive force of the pressure-sensitive adhesive becomes insufficient, In any case, it is difficult to obtain a favorable result in the adhesive properties.

In the composition of the present invention, the thermally conductive filler of the component c includes SiO ₂ , TiB ₂ , BN and Si.
₃ N _4, acidic fillers such as TiO _2, MgO, NiO,
Examples include basic fillers such as CuO, Al ₂ O ₃ , and Fe ₂ O _3. Of these, one type may be used alone, or two or more types may be used in combination. In the present invention, by the action of the reactive surfactant of the d component described below, even when various heat conductive fillers as described above are selectively used, a
In combination with the monomer composition of the components, there is no inconvenience when the viscosity of the composition before the photopolymerization sharply increases, and the above composition having excellent stability can be prepared.

The particle size of the thermally conductive filler of component c is as follows:
Although not particularly limited, generally, 0.5 to 250 μm
m, preferably 1 to 100 μm, more preferably 5 to 3
It preferably has an average particle size of 0 μm. The particle shape may be any shape such as a spherical shape, a needle shape, a flake shape, and a star shape. The choice of shape is determined by the rheology of the monomer of component a and the rheological properties of the composition.

Such a thermally conductive filler of the component c includes a
10 to 300 parts by weight, preferably 10 to 120 parts by weight, per 100 parts by weight of the component monomer (or a partial polymer thereof)
Used in parts by weight. When it is less than 10 parts by weight,
It is difficult to obtain a pressure-sensitive adhesive having good thermal conductivity.
When the amount is more than 0 parts by weight, the adhesiveness is hindered, and the adhesive force particularly at high temperatures tends to decrease.

In the composition of the present invention, the reactive surfactant of the d component is a surfactant having a radically polymerizable carbon-carbon double bond in the molecule, and has the same emulsification as a general surfactant. By having a solubilizing and dispersing power, when this is blended with the composition containing the above components a to c,
It suppresses a sharp increase in viscosity of the composition, contributes to the improvement of the stability of the composition, and exerts an excellent effect of improving coating workability and the like. In addition, since the above-mentioned double bond is present in the molecule, it participates in the polymerization reaction together with the monomer of the component a during photopolymerization by irradiation with ultraviolet light or the like, and is chemically strongly bonded to the photopolymer. It is possible to obtain a pressure-sensitive adhesive excellent in adhesive strength at high temperature (heat-shear holding power) without fear of adversely affecting the heat resistance of the product.

The reactive surfactants include higher alcohols
Ionic surfactants such as sodium sulfonate, sodium alkylbenzene sulfonate, sodium dialkyl sulfosuccinate, alkyl (allyl) ether phosphate, alkyl (allyl) ether sulfate, and alkyl phenyl ether Radical polymerizable carbon-carbon double bond is introduced into each molecule (side chain or main chain) among nonionic surfactants such as polyether, alkyl ether and polyoxyethylene polyoxypropylene block copolymer. One.
From the viewpoint of heat resistance and the purpose of use of the present invention, nonionic surfactants are particularly preferred.

The reactive surfactant of the d component is as follows:
0.001 to 3 parts by weight, preferably 0.001 part by weight, per 100 parts by weight of the monomer of the component a (or a partially polymerized product thereof).
It is used in a ratio of 5 to 1 part by weight. When the amount is less than 0.001 part by weight, the effect of improving the stability of the composition is not obtained, and the coating workability is deteriorated. When the amount is more than 3 parts by weight, heat resistance is impaired, and adhesion at high temperatures is particularly required. The force tends to decrease.

In preparing the composition of the present invention, first,
The above-mentioned monomer of the component a and the photopolymerization initiator of the component b are mixed together, and usually this premix is partially polymerized, and the coating is made of a partially polymerized product having a viscosity of about 5 to 500 poise. And make it into a syrup. Alternatively, a thixotropic agent such as fumed silica may be mixed with the premix of the monomer of the component a and the photopolymerization initiator of the component b to form a coatable syrup. it can.

Next, the heat-conductive filler of the component c, the reactive surfactant of the component d, and, if necessary, an additional photopolymerization initiator are mixed with the syrup-shaped material to obtain a composition for photopolymerization. Prepare the product. The composition further includes a pigment, if necessary.
Various known additives such as a filler, an antioxidant, and a tackifier may be added within a range that does not hinder photopolymerization by irradiation with ultraviolet rays or the like. In order to increase the shear strength of the pressure-sensitive adhesive, a crosslinking agent or an external crosslinking agent can be added.

Examples of the crosslinking agent include trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, 1,2-ethyleneglycol di (meth) acrylate, 1,6- Polyfunctional (meth) acrylates such as hexanediol-di (meth) acrylate
There is a Examples of the external crosslinking agent include polyfunctional isocyanate crosslinking agents such as tolylene diisocyanate, trimethylolpropane tolylene diisocyanate, diphenylmethane triisocyanate, and polyethylene glycol diglycidyl. Epoxy crosslinking agents such as ether, diglycidyl ether, and trimethylolpropane triglycidyl ether, melamine resin crosslinking agents, amino resin crosslinking agents, peroxide crosslinking agents, and the like.

In the present invention, the above composition is irradiated with ultraviolet rays, radiation, or the like to obtain a photopolymer. Irradiation with ultraviolet rays is performed in an oxygen-free atmosphere replaced with an inert gas such as nitrogen gas, or in a state where air is cut off by coating with an ultraviolet-permeable film. UV light has a wavelength range of 18
Although the electromagnetic radiation has a wavelength of 0 to 460 nm, electromagnetic radiation having a longer wavelength or a shorter wavelength may be used. Usable irradiation devices such as mercury arc, carbon arc, low pressure mercury lamp, medium / high pressure mercury lamp, and metal halide lamp are used as the ultraviolet light source. The intensity of the ultraviolet light can be appropriately set by adjusting the distance to the irradiation object and the voltage.
It is desirable to use light of 1 to 10 mW / cm ² . Also,
Radiation includes active energy rays, α rays, β rays, γ
An ionizing radiation such as a beam, a neutron beam, and an accelerating electron beam is used, and the irradiation amount is desirably about 1 to 10 Mrad. Note that ultraviolet rays and radiation may be used in combination.

According to the present invention, the photopolymer formed as described above is used as an acrylic heat-conductive pressure-sensitive adhesive which has pressure-sensitive adhesive properties under normal conditions and has good heat resistance and heat conductivity. It is. Further, the heat conductive pressure-sensitive adhesive is provided on one or both sides of the base material to form sheet-like or tape-like adhesive sheets. Here, the base material is preferably a metal foil such as a copper foil, an aluminum foil, a stainless steel foil, a beryllium copper foil as a material having good heat resistance and heat conductivity, and other materials such as a heat conductive silicone rubber. A polymer sheet having good thermal conductivity, a plastic film such as a polyester film or a polyimide film, a flame-retardant film or a non-woven fabric can also be used. The thickness of the substrate is usually 12 μm to 4 mm, and the thickness of the heat conductive pressure-sensitive adhesive layer provided on the substrate is usually 10 to 300 μm.
However, the present invention is not particularly limited to these.

The adhesive sheets of the present invention are obtained by applying the above composition onto a release liner and irradiating ultraviolet rays or radiation to form a layer of a heat conductive pressure-sensitive adhesive made of a photopolymer. It can be manufactured by transferring this on one or both sides of the substrate. Also, without using a release liner, the above composition is directly applied on a substrate, and irradiated with ultraviolet rays or radiation to form a layer of a heat conductive pressure-sensitive adhesive composed of a photopolymer. May be. An appropriate method can be adopted depending on the type of the base material and the like.

In the present invention, for example, in order to bond and fix an electronic component and a heat radiating member by using such an adhesive sheet, the above-mentioned adhesive sheet is interposed between the two. It suffices to perform pressure bonding using pressure-sensitive adhesiveness, whereby both can be fixed with good thermal conductivity and with good adhesive strength even at high temperatures. The above electronic components include, for example, I
Examples include a C-chip, a hybrid package, a multi-chip module, a power transistor, and a sealed integrated circuit made of plastic or metal. Examples of the heat dissipating member include a heat sink made of the above-described metal plate or sheet-like material exemplified as the base material, and other heat dissipators. The radiator may be an appropriate structure such as a form having a cooling fin.

The heat-conductive pressure-sensitive adhesive of the present invention or the adhesive sheet thereof is not limited to the bonding between the electronic component and the heat dissipating member, but may be applied to various fields such as building materials, vehicles, aircraft, ships and the like. It is needless to say that the same effect as described above can be obtained even when the member is used for the purpose of fixing the member at the same time.

[0031]

Next, an embodiment of the present invention will be described in more detail. In the following, all parts are parts by weight.

Example 1 75 parts of isooctyl acrylate, 15 parts of butyl acrylate
Part of a monomer consisting of 10 parts of acrylic acid and 2,2-dimethoxy-2-phenylacetone as a photopolymerization initiator.
The premix to which 1 part was added was exposed to ultraviolet rays in a nitrogen atmosphere to partially polymerize, thereby obtaining a coatable syrup having a viscosity of about 40 poise. Al ₂ O ₃ (average particle size: 3.7 μm) 10 as a thermally conductive filler
0 parts of a reactive surfactant represented by the following formula (1):
One part of the composition was prepared by adding 0.2 part of trimethylolpropane triacrylate as a cross-linking agent.

[0033]

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This composition did not show an excessive increase in viscosity during or after preparation, and was excellent in stability. This composition was applied on a release liner made of a polyester film surface-treated with a release agent, and irradiated with 900 mj / cm ² ultraviolet light from a high-pressure mercury lamp having a light intensity of 5 mW / cm ² in a nitrogen gas atmosphere to perform photopolymerization. Treated to form a layer of 50 μm thick thermally conductive pressure sensitive adhesive. This layer is transferred to both sides of a 30 μm-thick aluminum foil as a substrate,
The adhesive sheet had a total thickness of 130 μm.

Example 2 85 parts of 2-ethylhexyl acrylate, 5 parts of acrylic acid
And a monomer consisting of 10 parts of caprolactone-modified acrylate [“Alonix M-5300” manufactured by Toa Gosei Chemical Co., Ltd.] and 2,2-dimethoxy-2-phenylacetone as a photopolymerization initiator. The premix to which 1 part was added was exposed to ultraviolet light in a nitrogen atmosphere to partially polymerize to obtain a coatable syrup having a viscosity of about 100 poise. 100 parts of this syrup is filled with BN as a heat conductive filler.
(Average particle diameter 8 μm) 40 parts, a reactive surfactant represented by the following formula (2) 0.05 part, and trimethylolpropane triacrylate 0.2 part as a cross-linking agent were added. A composition was prepared.

[0036]

Embedded image

This composition did not show an extreme increase in viscosity during or after the preparation and was excellent in stability. This composition was applied to both sides of an aluminum foil having a thickness of 30 μm as a substrate, and the light intensity was 5 mW / cm under a nitrogen gas atmosphere.
Photopolymerization process by irradiating ultraviolet rays of 900 mj / cm ² in ² high-pressure mercury lamp, thickness to form a layer of 50μm in heat-conductive and pressure-sensitive adhesive, overall thickness adhesive sheet of 130 .mu.m - was collected by .

Comparative Example 1 A composition was obtained in the same manner as in Example 1 except that the reactive surfactant represented by the formula (1) was not added, and the composition was to be applied on a release liner. However, application became difficult due to an increase in viscosity, and a uniform adhesive sheet could not be obtained.

Comparative Example 2 An adhesive sheet was obtained in the same manner as in Example 1 except that the amount of the reactive surfactant represented by the formula (1) was changed to 10 parts.

COMPARATIVE EXAMPLE 3 95 parts of 2-ethylhexyl acrylate and 5 parts of acrylic acid were mixed with 210 parts of ethyl acetate in the presence of 0.4 part of 2,2-azobisisobutyronitrile under a nitrogen atmosphere. 60 ~
The solution was subjected to solution polymerization while stirring at 80 ° C.
A copolymer solution having 0 poise, a polymerization rate of 99.2% by weight, and a solid content of 30% by weight was obtained. Into this solution was added MgO (average particle diameter 8 μm)
m) 60 parts, 0.1 part of the reactive surfactant represented by the formula (2) used in Example 2, and 3 parts of a polyfunctional isocyanate-based cross-linking agent were added, and a heat-conductive pressure-sensitive adhesive was added. Prepared.

This heat-conductive pressure-sensitive adhesive did not show an extreme increase in viscosity during or after preparation and was excellent in stability. This pressure-sensitive adhesive is applied on a release liner made of a polyester film surface-treated with a release agent, dried in a hot air drier at 40 ° C. for 5 minutes, and further dried at 130 ° C. for 5 minutes to obtain a thickness. A layer of 50 μm thermally conductive pressure sensitive adhesive was formed. This layer has a thickness of 30 μm as a substrate.
Is transferred to both sides of copper foil, and the total thickness is 130μm.
I got it.

With respect to each of the adhesive sheets of Examples 1 and 2 and Comparative Examples 2 and 3, an adhesive force test (heat-resistant shear holding force test) and a heat resistance test at high temperature were performed by the following methods. . These results were as shown in Table 1.

<Heat resistance shear strength test> One end of the aluminum plate (125 mm x 25 mm x 0.4 mm) in the longitudinal direction was
An adhesive sheet (width: 10 mm) is attached so that the adhesive area is 20 mm × 10 mm, left at 80 ° C. for 30 minutes, and then a load of 500 g is applied at 80 ° C. and held without falling for 120 minutes or more. Was tested.

<Thermal Resistance Test> The transistor in the TO-220 package was bonded and fixed to a heat sink, which was immersed in water and maintained at a constant temperature, using an adhesive sheet at a pressure of 2 kg / cm ² . Thereafter, a fixed amount of output was supplied to the transistor, and the temperature difference (T2−T1) between the transistor temperature (T2) and the surface temperature (T1) below the adhesive sheet was measured. From this temperature difference, the thermal resistance was calculated according to the following equation. Thermal resistance (° C./cm ² / W) = (T ² −T 1) × A / P A: Transistor area (cm ² ) P: Transistor power consumption (W)

The temperature (T2) of the transistor was measured by a thermocouple spot-welded to the metal base of the transistor package. In addition, the surface temperature (T1) below the adhesive sheet is determined by making a small hole in the heat sink,
It was measured by pushing in a thermocouple. At that time, the thermocouple was held as close as possible so as not to affect the bonding area of the bonding sheet.

[0046]

From the above results, the compositions before photopolymerization prepared in Examples 1 and 2 have excellent stability during or after the preparation, and do not impede the coating workability at the time of preparing an adhesive sheet. It can be seen that each of the adhesive sheets produced by using the adhesive sheets satisfies the heat-resistant shear holding force and has excellent thermal conductivity.

[0048]

As described above, according to the present invention, a photopolymerization initiator, a heat conductive filler and a specific surfactant are further blended with an acrylic monomer or a partial polymer thereof, and this composition is prepared. By photopolymerizing after application to the substrate, the composition has excellent stability, has no problems in coating workability, etc., and has excellent thermal conductivity and adhesiveness. A heat-conductive pressure-sensitive adhesive having a large shear holding force) and an adhesive sheet thereof can be obtained. In this case, there is no particular limitation on the monomer composition and the type of the heat-conductive filler, and the desired one can be obtained. Since it can be used arbitrarily, it is also excellent in versatility, fixing electronic components, especially fixing electronic components to heat dissipation members, and fixing members in various fields such as construction materials, vehicles, aircraft, ships, etc. It can be widely used for purposes such as.

Continuation of the front page (72) Inventor Shigeki Muta 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation

Claims (3)

[Claims] 1. An a) alkyl group having an average of 2 to 14 carbon atoms.
Monomer composed of 70 to 100% by weight of a main monomer mainly composed of alkyl (meth) acrylate and 30 to 0% by weight of a copolymerizable monomer having a polar group in the molecule. (Or a partial polymer thereof) 100 parts by weight, b) 0.01 to 5 parts by weight of a photopolymerization initiator, c) thermal conductive filler 10 to 10 parts by weight
Heat conduction comprising a photopolymer of a composition comprising 300 parts by weight, d) 0.001 to 3 parts by weight of a reactive surfactant having a radically polymerizable carbon-carbon double bond in the molecule. Pressure-sensitive adhesive. 2. The heat-conductive pressure-sensitive adhesive according to claim 1, wherein the reactive surfactant of the component d is a nonionic surfactant. 3. An adhesive sheet characterized in that the heat conductive pressure-sensitive adhesive layer according to claim 1 is provided on one or both surfaces of a substrate.