JP2005272505A - Heat-conductive pressure-sensitive adhesive composition and heat-conductive sheet-like formed article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-conductive pressure-sensitive adhesive composition which has sufficient pressure-sensitive adhesiveness and heat conductivity, when used, and can safely and easily be peeled from an adherend, after used, and to provide a heat-conductive pressure-sensitive adhesive sheet. <P>SOLUTION: This heat-conductive pressure-sensitive adhesive composition comprises 70 to 170 pts. wt. of a heat-conductive inorganic compound, 0.05 to 10 pts. wt. of a compound having a melting point of 120 to 200°C and a mol. wt. of <1,000, and 100 pts. wt. of a (meth)acrylate copolymer obtained by polymerizing 5 to 70 pts. wt. of a monomer mixture comprising 40 to 100 wt. % of a (meth)acrylate monomer, 60 to 0 wt. % of a monomer having an organic acid group, and 0 to 20 wt. % of a monomer capable of being copolymerized with the monomers, in the presence of 100 pts. wt. of a copolymer comprising 80 to 99.9 wt. % of units originated from a (meth)acrylate monomer, 0.1 to 20 wt. % of units originated from a monomer having an organic acid group, 0 to 10 wt. % of units originated from a monomer having a functional group except the organic acid group, and 0 to 10 wt. % of units originated from a monomer capable of being copolymerized with the monomers. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat conductive pressure-sensitive adhesive composition and a heat conductive sheet-like molded article comprising the same.

In recent years, electronic components such as plasma display panels (PDP), integrated circuit (IC) chips, and the like have increased in heat generation as their performance has increased. As a result, there is a need to take measures against functional failures due to temperature rise. In general, a method of diffusing heat by attaching a heat sink such as a heat sink, a heat radiating metal plate, or a heat radiating fin to a heat generating body such as an electronic component is employed. Various types of heat conductive sheets are used to efficiently conduct heat from the heating element to the heat radiating body. In general, a pressure-sensitive adhesive heat radiating sheet is required for fixing the heat generating element and the heat radiating element. Is done.
The pressure-sensitive adhesive heat-dissipating sheet is an adhesive or sticky sheet that fixes the heat-generating body and the heat-dissipating body, but can be easily peeled off from the heat-generating body or the heat-dissipating body when recycled or discarded after use. It is demanded.
In Patent Document 1, a microcapsule containing a thermally expandable substance such as isobutane or pentane is contained in a sheet, and the thermally expandable substance is obtained by heating the sheet to a temperature higher than that during normal use after use of the sheet. A method for improving the peelability of the sheet by expanding and providing irregularities on the surface of the sheet in contact with the adherend is disclosed. However, this method is a dangerous method in which a substance with a high risk of combustion / explosion is vaporized, and there is also a problem that an expensive microcapsule is used.

  Patent Document 2 discloses that a sheet including a foam component having a t-butyloxycarbonyl structure and a foaming initiator that generates an acid by radiation or ultraviolet rays is exposed to radiation or ultraviolet rays at a high temperature after use. It discloses a method for improving releasability by generating and foaming a gas. However, this method also generates a combustible gas that may burn or explode at a high temperature, causing a safety problem.

JP 2002-134666 A JP 2004-043732 A

  As described above, the pressure-sensitive adhesive heat-dissipating sheet is required to be easily peelable from the adherend after use, but it has not yet been found that there is no safety problem and is economically advantageous. The current situation is not.

  In view of the above circumstances, an object of the present invention is to have sufficient pressure-sensitive adhesiveness and thermal conductivity at the time of use, and after use, a thermally conductive pressure-sensitive sensor that can be safely and easily peeled off from the adherend. It is in providing an adhesive composition and a heat conductive pressure sensitive adhesive sheet.

  The inventors of the present invention have continually studied about a heat conductive pressure-sensitive adhesive composition, and have a specific structure by employing a specific polymerization method in the synthesis of a (meth) acrylic acid ester copolymer ( By obtaining a (meth) acrylic acid ester copolymer and using it as a pressure-sensitive adhesive, and adding a compound having a melting point of 120 to 200 ° C. and a molecular weight of less than 1000 to the pressure-sensitive adhesive, The present inventors have found that the object can be achieved, and have completed the present invention based on this finding.

  Thus, according to the present invention, the unit derived from the (meth) acrylic acid ester monomer (a1) that forms a homopolymer having a glass transition temperature of −20 ° C. or lower, 80 to 99.9% by weight, an organic acid group Derived from monomer unit (a2) containing 0.1 to 20% by weight, monomer unit containing functional group other than organic acid group (a3) from 0 to 10% by weight and monomers copolymerizable therewith In the presence of 100 parts by weight of the copolymer (A1) containing 0 to 10% by weight of the monomer unit (a4), a homopolymer having a glass transition temperature of −20 ° C. or lower is formed (meta ) Acrylic acid ester monomer (a5m) 40-100% by weight, monomer having organic acid group (a6m) 60-0% by weight, and monomer copolymerizable therewith (a7m) 0-20% by weight Obtained by polymerizing 5 to 70 parts by weight of a monomer mixture (A2m) comprising (Meth) acrylic acid ester copolymer (A) 100 parts by weight, thermally conductive inorganic compound (B) 70-170 parts by weight, and melting point 120-200 ° C. and molecular weight less than 1000 (C) 0.05- A thermally conductive pressure sensitive adhesive composition comprising 10 parts by weight is provided.

Moreover, according to this invention, the heat conductive sheet-like molded object which consists of the said heat conductive pressure sensitive adhesive composition is provided.
Moreover, according to this invention, the heat conductive sheet-like molded object which consists of a base material and the said heat conductive pressure-sensitive-adhesive composition layer formed in the single side | surface or both surfaces is provided.

  The heat conductive pressure-sensitive adhesive composition of the present invention has sufficient pressure-sensitive adhesiveness and heat conductivity when used, and can be safely and easily peeled off from the adherend after use. . Therefore, the heat conductive sheet-like molded body obtained from this is useful as a heat conductive sheet for efficiently conducting heat conduction from a heat generating body such as an electronic component such as a plasma display panel (PDP) to a heat radiating body.

Hereinafter, the present invention will be described in detail.
The heat conductive pressure sensitive adhesive composition of this invention contains a (meth) acrylic acid ester copolymer (A) as a 1st essential component. The (meth) acrylic acid ester copolymer (A) is a unit derived from a (meth) acrylic acid ester monomer (a1) 80 to 99.9 that forms a homopolymer having a glass transition temperature of −20 ° C. or lower. % By weight, monomer unit having organic acid group (a2) 0.1 to 20% by weight, monomer unit having functional group other than organic acid group (a3) 0 to 10% by weight, and copolymerized therewith Monomer weight with a glass transition temperature of −20 ° C. or lower in the presence of 100 parts by weight of copolymer (A1) containing 0 to 10% by weight of monomer units (a4) derived from possible monomers (Meth) acrylic acid ester monomer (a5m) 40 to 100% by weight, monomer having organic acid group (a6m) 60 to 0% by weight and monomer copolymerizable with these (a7m) ) Monomer mixture (A2m) consisting of 0 to 20% by weight 5 to 70% Polymerizing the obtained.
In the present invention, (meth) acrylic acid ester means acrylic acid ester and / or methacrylic acid ester.

The copolymer (A1) used to obtain the (meth) acrylic acid ester copolymer (A) forms a homopolymer having a glass transition temperature of −20 ° C. or less. Body-derived unit (a1) 80 to 99.9% by weight, monomer unit having organic acid group (a2) 0.1 to 20% by weight, monomer unit containing functional group other than organic acid group ( a3) 0 to 10% by weight and a monomer unit derived from a monomer copolymerizable therewith (a4) containing 0 to 10% by weight.
The (meth) acrylic acid ester monomer (a1m) that gives the unit (a1) derived from the (meth) acrylic acid ester monomer that forms a homopolymer having a glass transition temperature of −20 ° C. or lower is particularly limited. However, for example, ethyl acrylate (glass transition temperature of homopolymer is −24 ° C.), propyl acrylate (-37 ° C.), butyl acrylate (-54 ° C.), sec-butyl acrylate ( -22 ° C), heptyl acrylate (-60 ° C), hexyl acrylate (-61 ° C), octyl acrylate (-65 ° C), 2-ethylhexyl acrylate (-50 ° C), acrylic acid 2-methoxyethyl (-50 ° C), 3-methoxypropyl acrylate (-75 ° C), 3-methoxybutyl acrylate (-56 ° C), 2-ethoxymethyl acrylate (- 0 ° C.), octyl methacrylate (same -25 ° C.), can be mentioned decyl methacrylate (same -49 ° C.).
These (meth) acrylic acid ester monomers (a1m) may be used alone or in combination of two or more.
These (meth) acrylic acid ester monomers (a1m) have a monomer unit (a1) derived from 80 to 99.9% by weight in the (meth) acrylic acid ester copolymer (A1), preferably Is used in the polymerization in an amount of 85 to 99.5% by weight. If the usage-amount of a (meth) acrylic acid ester monomer (a1m) is less than the said range minimum, the pressure-sensitive adhesiveness in the vicinity of room temperature of the heat conductive pressure-sensitive-adhesive composition obtained from this will fall.

The monomer (a2m) that gives the monomer unit (a2) having an organic acid group is not particularly limited, and representative examples thereof include organic acid groups such as a carboxyl group, an acid anhydride group, and a sulfonic acid group. In addition to these, monomers containing sulfenic acid groups, sulfinic acid groups, phosphoric acid groups, and the like can also be used. Specific examples of the monomer having a carboxyl group include α, β-ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; α, β- such as itaconic acid, maleic acid, and fumaric acid. And ethylenically unsaturated polyvalent carboxylic acids; α, β-ethylenically unsaturated polyvalent carboxylic acid partial esters such as methyl itaconate, butyl maleate and propyl fumarate; Moreover, what has group which can be induced | guided | derived to a carboxyl group by hydrolysis etc., such as maleic anhydride and itaconic anhydride, can be used similarly.
Specific examples of the monomer having a sulfonic acid group include allyl sulfonic acid, methallyl sulfonic acid, vinyl sulfonic acid, styrene sulfonic acid, α, β-unsaturated sulfonic acid such as acrylamide-2-methylpropane sulfonic acid, and the like. These salts can be mentioned.
Among these monomers having an organic acid group, monomers having a carboxyl group are preferable, and among them, acrylic acid and methacrylic acid are preferable. These are industrially inexpensive and can be easily obtained, have good copolymerizability with other monomer components, and are preferable in terms of productivity.

These monomers (a2m) having an organic acid group may be used alone or in combination of two or more.
The monomer (a2m) having these organic acid groups has a monomer unit (a2) derived therefrom of 0.1 to 20% by weight in the (meth) acrylic acid ester copolymer (A1), preferably It is used for the polymerization in an amount of 0.5 to 15% by weight. When the monomer (a2m) is used in excess of 20% by weight, the thickening during the polymerization is remarkably solidified, making it difficult to handle the polymer.
The monomer unit (a2) having an organic acid group can be easily introduced into the copolymer by polymerization of the monomer (a2m) having an organic acid group, as described above. After forming the copolymer, an organic acid group may be introduced by a known polymer reaction.

The copolymer (A1) used for obtaining the (meth) acrylic acid ester copolymer (A) is a polymer unit derived from a monomer (a3m) containing a functional group other than an organic acid group ( a3) It may contain 10% by weight or less.
Examples of functional groups other than organic acid groups include hydroxyl groups, amino groups, amide groups, epoxy groups, mercapto groups, and the like.
Examples of the monomer having a hydroxyl group include (meth) acrylic acid hydroxyalkyl esters such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate.
Examples of the monomer containing an amino group include N, N-dimethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and aminostyrene.
Examples of monomers having an amide group include α, β-ethylenically unsaturated carboxylic acid amide monomers such as acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, and N, N-dimethylacrylamide. Can be mentioned.
Examples of the monomer having an epoxy group include glycidyl (meth) acrylate and allyl glycidyl ether.
As the monomer (a3m) containing a functional group other than an organic acid group, one type may be used alone, or two or more types may be used in combination.
In the monomer (a3m) having a functional group other than these organic acid groups, the monomer unit (a3) derived therefrom is 10% by weight or less in the (meth) acrylate copolymer (A1). Used in the polymerization in such amounts. When the monomer (a3m) is used in an amount exceeding 10% by weight, the viscosity during polymerization is remarkably increased and solidified, making it difficult to handle the polymer.

The copolymer (A1) is a unit derived from a (meth) acrylic acid ester monomer (a1), a monomer unit (a2) having an organic acid group, and an organic compound that forms a homopolymer of −20 ° C. or lower. In addition to the monomer unit (a3) containing a functional group other than an acid group, the monomer unit (a4) derived from a monomer (a4m) copolymerizable with these monomers is contained. May be.
A monomer (a4m) may be used individually by 1 type, and may use 2 or more types together.
The amount of the monomer unit (a4) derived from the monomer (a4m) is an amount that is 10% by weight or less, preferably 5% by weight or less of the copolymer (A1).
Although a monomer (a4m) is not specifically limited, (meth) acrylic acid ester other than the (meth) acrylic acid ester monomer (a1m) which forms the homopolymer which will be -20 degrees C or less as the specific example. Monomer, α, β-ethylenically unsaturated polyvalent carboxylic acid complete ester, alkenyl aromatic monomer, conjugated diene monomer, non-conjugated diene monomer, vinyl cyanide monomer, carvone Examples thereof include acid unsaturated alcohol esters and olefinic monomers.

Specific examples of (meth) acrylic acid ester monomers other than the (meth) acrylic acid ester monomer (a1m) forming a homopolymer of −20 ° C. or lower include methyl acrylate (homopolymer glass) Examples of the transition temperature include 10 ° C., methyl methacrylate (105 ° C.), ethyl methacrylate (63 ° C.), propyl methacrylate (25 ° C.), butyl methacrylate (20 ° C.), and the like.
Specific examples of α, β-ethylenically unsaturated polyvalent carboxylic acid complete esters such as dimethyl itaconate, dibutyl maleate and dipropyl fumarate include dimethyl fumarate, diethyl fumarate, dimethyl maleate, diethyl maleate, itacon Examples thereof include dimethyl acid.
Specific examples of the alkenyl aromatic monomer include styrene, α-methylstyrene, methyl α-methylstyrene, vinyl toluene and divinylbenzene.

Specific examples of the conjugated diene monomer include 1,3-butadiene, 2-methyl-1,3-butadiene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, and 2-chloro- Examples thereof include 1,3-butadiene and cyclopentadiene.
Specific examples of the non-conjugated diene monomer include 1,4-hexadiene, dicyclopentadiene, ethylidene norbornene and the like.
Specific examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethylacrylonitrile and the like.
Specific examples of the carboxylic acid unsaturated alcohol ester monomer include vinyl acetate.
Specific examples of the olefin monomer include ethylene, propylene, butene, pentene and the like.

The weight average molecular weight (Mw) of the copolymer (A1) is preferably in the range of 100,000 to 400,000, and in the range of 150,000 to 300,000 as measured by gel permeation chromatography (GPC method). It is particularly preferable that
The copolymer (A1) is a monomer other than the (meth) acrylic acid ester monomer (a1m), the monomer having an organic acid group (a2m), or an organic acid group, which forms a homopolymer having a temperature of −20 ° C. or lower. It can be obtained by copolymerizing a monomer (a3m) containing a functional group and a monomer (a4m) copolymerizable with these monomers used as necessary.
The polymerization method is not particularly limited, and may be any of solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization, and the like, and may be other methods. Solution polymerization is preferred, and among these, solution polymerization using a carboxylic acid ester such as ethyl acetate or ethyl lactate or an aromatic solvent such as benzene, toluene or xylene as the polymerization solvent is preferred.
In the polymerization, the monomer may be added in portions to the polymerization reaction vessel, but it is preferable to add the whole amount at once.

Although the method for initiating polymerization is not particularly limited, it is preferable to use a thermal polymerization initiator as the polymerization initiator (D1). The thermal polymerization initiator is not particularly limited, and may be either a peroxide or an azo compound.
Examples of peroxide polymerization initiators include hydroperoxides such as t-butyl hydroperoxide; peroxides such as benzoyl peroxide and cyclohexanone peroxide; persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate; Can do.
These peroxides can also be used as a redox catalyst in appropriate combination with a reducing agent.
As the azo compound polymerization initiator, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile) Etc.
Although the usage-amount of a polymerization initiator (D1) is not specifically limited, Usually, it is the range of 0.01-50 weight part with respect to 100 weight part of monomers.
There are no particular restrictions on the other polymerization conditions (polymerization temperature, pressure, stirring conditions, etc.) of these monomers.

  After completion of the polymerization reaction, the obtained polymer is separated from the polymerization medium as necessary. The separation method is not particularly limited. In the case of solution polymerization, a polymer can be obtained by placing the polymerization solution under reduced pressure and distilling off the polymerization solvent.

  The (meth) acrylic acid ester copolymer (A) used in the present invention has a glass transition temperature of −20 ° C. or lower in the presence of 100 parts by weight of the copolymer (A1) obtained as described above. (Meth) acrylic acid ester monomer (a5m) of 40 to 100% by weight, monomer having organic acid group (a6m) of 60 to 0% by weight and a monomer copolymerizable therewith It is obtained by polymerizing 5 to 70 parts by weight of a monomer mixture (A2m) consisting of 0 to 20% by weight of the body (a7m).

As an example of the (meth) acrylic acid ester monomer (a5m) that forms a homopolymer having a glass transition temperature of −20 ° C. or lower, (meth) acrylic acid ester used for the synthesis of the polymer (A1) The same (meth) acrylic acid ester monomer as the body (a1m) can be mentioned.
The (meth) acrylic acid ester monomer (a5m) may be used alone or in combination of two or more.
The ratio of the (meth) acrylate monomer (a5m) in the monomer mixture (A2m) is 40 to 100% by weight, preferably 60 to 95% by weight.
When the ratio of the (meth) acrylic acid ester monomer (a5m) is less than the above range, the pressure-sensitive adhesiveness and flexibility of the heat conductive pressure-sensitive adhesive composition obtained using the copolymer (A). Is insufficient.

Examples of the monomer (a6m) having an organic acid group include the same monomers having an organic acid group as exemplified as the monomer (a2m) used for the synthesis of the polymer (A1). .
As the monomer having an organic acid group (a6m), one type may be used alone, or two or more types may be used in combination.
The ratio of the monomer (a6m) having an organic acid group in the monomer mixture (A2m) is 60 to 0% by weight, preferably 40 to 5% by weight.
When the ratio of the monomer (a6m) having an organic acid group is more than the above range, the hardness of the heat conductive pressure-sensitive adhesive composition obtained using the copolymer (A) is increased, particularly at a high temperature ( The pressure-sensitive adhesiveness at 100 ° C. decreases.
Monomer (a7m) copolymerizable with (meth) acrylate monomer (a5m) and monomer having organic acid group (a6m) to form a homopolymer having a glass transition temperature of -20 ° C. or lower As an example of (), the same monomer as exemplified as the monomer (a3m) or monomer (a4m) used for the synthesis of the polymer (A1) can be mentioned.

A polyfunctional monomer having two or more polymerizable unsaturated bonds can also be used in combination. By copolymerizing the polyfunctional monomer, intramolecular and / or intermolecular crosslinking can be introduced into the copolymer to increase the cohesive force as a pressure-sensitive adhesive.
Polyfunctional monomers include 1,6-hexanediol di (meth) acrylate, 1,2-ethylene glycol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, polyethylene glycol di (meth) ) Acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ditrimethylolpropane tri ( (Meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, urea Polyfunctional (meth) acrylates such as poly (meth) acrylate; substituted triazines such as 2,4-bis (trichloromethyl) -6-p-methoxystyrene-5-triazine; monoethylene such as 4-acryloxybenzophenone System unsaturated aromatic ketones, etc. can be used.

  The usage-amount of a monomer mixture (A2m) is 5-70 weight part with respect to 100 weight part of copolymers (A1), Preferably it is 10-50 weight part. When the amount of the monomer mixture (A2m) is less than the lower limit of the above range, the (meth) acrylic acid ester copolymer (A) and the thermally conductive inorganic compound (B) cannot be uniformly mixed, and thus obtained. The high temperature holding power, heat conductivity, etc. of the heat conductive sheet-like molded article to be obtained are reduced. On the other hand, when the upper limit of the above range is exceeded, the polymerization reaction does not proceed sufficiently, the high temperature adhesive strength of the resulting thermally conductive sheet-like molded product is poor, and problems such as odor due to unreacted monomers occur.

The conditions for polymerizing the monomer mixture (A2m) in the presence of 100 parts by weight of the copolymer (A1) are not particularly limited except for the method for initiating polymerization, and the synthesis of the copolymer (A1) Similar conditions can be shown.
In the present invention, it is preferable to use a thermal polymerization initiator (D2) as a polymerization initiation method for polymerizing the monomer mixture (A2m) in the presence of the copolymer (A1). When a photopolymerization initiator is used instead of the thermal polymerization initiator, the adhesive strength of the sheet formed from the resulting heat conductive pressure-sensitive adhesive composition is poor.
Examples of the thermal polymerization initiator (D2) include the same type of thermal polymerization initiators as those exemplified as the polymerization initiator (D1) used for the synthesis of the copolymer (A1). An initial temperature of 120 ° C. or higher and 170 ° C. or lower is preferable.
Although the usage-amount of a thermal-polymerization initiator (D2) is not specifically limited, Usually, it is the range of 0.1-50 weight part with respect to 100 weight part of monomer mixtures (A2m).
The polymerization conversion rate of the monomer mixture (A2m) is preferably 95% by weight or more. If the polymerization conversion rate is too low, a monomer odor remains in the obtained heat conductive sheet, which is not preferable.

The heat conductive pressure-sensitive adhesive composition of the present invention contains a heat conductive inorganic compound (B) as an essential component.
Examples of the thermally conductive inorganic compound (B) include metal oxides such as alumina, magnesium oxide, beryllium oxide and titanium oxide; metal nitrides such as boron nitride, silicon nitride and aluminum nitride; carbides such as silicon carbide; copper and silver Metals such as iron, aluminum and nickel; Carbon compounds such as diamond and carbon; Silica powder such as quartz and quartz glass, and the like. Preferably, the metal hydroxide of Group 2 or Group 13 of the Periodic Table is used. Oxide, oxide or nitride. Among them, the metal hydroxide (B1) of Group 2 or Group 13 of the periodic table is preferable because it can impart flame retardancy to the heat conductive pressure-sensitive adhesive composition of the present invention.
Examples of the Group 2 metal include magnesium, calcium, strontium, barium, and the like. Examples of the Group 13 metal include aluminum, gallium, and indium.
These heat conductive inorganic compounds (B) may be used individually by 1 type, and may use 2 or more types together.
The shape of the heat conductive inorganic compound (B) is not particularly limited, and may be any of a spherical shape, a needle shape, a fiber shape, a scale shape, a dendritic shape, a flat plate shape, and an indefinite shape.
Of the metal hydroxides (B1) of Group 2 or Group 13 of the periodic table, aluminum hydroxide is particularly preferable. By using aluminum hydroxide, excellent flame retardancy can be imparted to the heat conductive pressure-sensitive adhesive composition of the present invention.

As the aluminum hydroxide, one having a particle size of usually 0.2 to 100 μm, preferably 0.7 to 50 μm is used. Moreover, it is preferable to have an average particle diameter of 1 to 50 μm. When the average particle size is less than 1 μm, the viscosity of the pressure-sensitive adhesive composition increases, which may make it difficult to knead the polymer and the thermally conductive inorganic compound, and at the same time, the hardness increases, and sheet-like molding is performed. There is a risk of reducing the adhesion of the body.
On the other hand, when the thickness exceeds 50 μm, the pressure-sensitive adhesive composition or the sheet-like molded article becomes too soft, and may cause excessive pressure-sensitive adhesion, decrease in adhesive strength at high temperature, or thermal deformation at high temperature. is there.

In this invention, the usage-amount of a heat conductive inorganic compound (B) is the range of 70-170 weight part with respect to 100 weight part of copolymers (A).
When the amount used is less than 70 parts by weight, there are problems such as high-temperature adhesive strength and thermal conductivity reduction, and conversely, when it exceeds 170 parts by weight, the hardness increases and the problem of poor adhesion occurs.

  The heat conductive pressure-sensitive adhesive composition of the present invention contains a compound (C) having a melting point of 120 to 200 ° C. and a molecular weight of less than 1000 as an essential component.

  The compound (C) exists as a solid at a temperature (about 100 ° C. or lower) at which the heat conductive pressure-sensitive adhesive composition of the present invention is normally used as a PDP heat dissipation sheet or the like, but is recycled or discarded after use. As a treatment of, easy peeling by heating to a temperature of 120 to 200 ° C. and bleeding (exuding) between the adherend and the heat conductive pressure sensitive adhesive sheet, that is, on the surface of the heat conductive pressure sensitive adhesive sheet. It imparts sex.

  The compound (C) is not particularly limited as long as the melting point is 120 to 200 ° C. and the molecular weight is less than 1000. When the melting point is less than 120 ° C., the heat conductive pressure-sensitive adhesive composition of the present invention is already easily peeled off at a temperature (about 100 ° C. or less) normally used as a PDP heat radiating sheet and the like, and heat is radiated from the adherend. The sheet may fall off. On the other hand, when the melting point exceeds 200 ° C., the heat treatment temperature needs to exceed 200 ° C., so that the copolymer (A) may be decomposed or seized, resulting in a decrease in peelability. Further, when the molecular weight of the compound (C) is 1000 or more, the viscosity is high even if the melting point is reached, it becomes difficult to bleed and it becomes difficult to impart easy peelability.

  In the heat conductive pressure-sensitive adhesive composition of the present invention, the compound (C) is preferably an aliphatic amide compound having a melting point of 120 to 200 ° C. and a molecular weight of less than 1000. Examples of these compounds include methylene bis stearamide (melting point: 130 ° C.), ethylene bis stearamide (145 ° C.), ethylene bislauric acid amide (157 ° C.), ethylene biscapric acid amide (161 ° C.). ), Bisstearic acid amide (137 ° C.), bislauric acid amide (143 ° C.), and the like. These may be used alone or in combination of two or more.

  The amount of the compound (C) used is usually 0.05 to 10 parts by weight, preferably 0.2 to 8 parts by weight, more preferably 0.3 to 100 parts by weight with respect to 100 parts by weight of the copolymer (A). 5 parts by weight. If the amount used is less than the above range, easy peelability is hardly exhibited, and if it exceeds the above range, the adhesive strength of the heat conductive pressure-sensitive adhesive composition at a normal use temperature may be lowered.

  In the thermally conductive pressure-sensitive adhesive composition of the present invention, the thermally conductive inorganic compound (B) is a metal hydroxide (B1) of Group 2 or Group 13 of the Periodic Table, and the (meth) acrylic The acid ester copolymer (A) is preferably foamed.

  The expansion ratio is not particularly limited, but is more preferably 1.05 times to 1.4 times. By setting the expansion ratio within the range, it is possible to obtain a heat conductive pressure-sensitive adhesive composition having an excellent balance between hardness and pressure-sensitive adhesiveness and excellent shape followability.

  The foaming method is not particularly limited, and various methods can be used. For example, a syrupy form formed by mixing the copolymer (A1), the monomer mixture (A2m), the metal hydroxide (B1) of Group 2 or 13 of the periodic table, and the compound (C). (1) Method of taking in air in the atmosphere by stirring; (2) Method of blowing in gas such as nitrogen; (3) Copolymer (A1) or monomer such as water (4) A method in which a fluid having low compatibility with the mixture (A2m) is incorporated as fine particles by stirring; (4) A method in which a fluid dissolved in a viscous mixture is generated as bubbles or liquid bubbles by decompression or heating; 5) A method of mixing a photodegradable foaming agent that decomposes by light and then irradiating with light; (6) A method of mixing a thermally decomposable foaming agent that decomposes by heat and then heating. Among these methods, foaming is preferably performed using a foaming agent, particularly a foaming agent that decomposes by heat to generate gas (thermally decomposable foaming agent). Examples of the thermally decomposable blowing agent include p, p'-oxybis (benzenesulfonylhydrazide), azodicarboxamide and the like. 0.1-3 weight part is preferable with respect to 100 weight part of copolymers (A), and, as for the usage-amount of a foaming agent, 0.3-2 weight part is more preferable. By selecting the amount of foaming agent used in this way, the expansion ratio can be adjusted to a preferred range, and the heat-conductive pressure-sensitive adhesive has an excellent balance between hardness and pressure-sensitive adhesiveness, and has excellent shape following properties. An agent composition can be obtained.

The heat conductive pressure-sensitive adhesive composition of the present invention contains the copolymer (A), the heat conductive inorganic compound (B), the compound (C) and the foaming agent used as required in the above ratio, and if necessary. , Pigments, other fillers, flame retardants, anti-aging agents, thickeners, tackifiers, and the like.
The pigment can be used regardless of organic type or inorganic type such as carbon black and titanium dioxide.
Other fillers include inorganic compounds and organic compound fine particles. You may add nanoparticles, such as fullerene and a carbon nanotube.
Examples of the flame retardant include ammonium polyphosphate, zinc borate, tin compound, organic phosphorus compound, red phosphorus compound, and silicone flame retardant.
As an antioxidant, there is a high possibility of inhibiting radical polymerization, so that it is not usually used, but an antioxidant such as polyphenol, hydroquinone or hindered amine can be used as necessary.
As the thickener, inorganic polymer fine particles such as acrylic polymer particles and fine silica, and reactive inorganic compounds such as magnesium oxide can be used.
Examples of tackifiers include terpene resins, terpene phenol resins, rosin resins, petroleum resins, coumarone-indene resins, phenol resins, hydrogenated rosin esters, disproportionated rosin esters, xylene resins, and the like. it can.

Furthermore, in order to increase the cohesive force as a pressure-sensitive adhesive and improve heat resistance, etc., the heat conductive pressure-sensitive adhesive composition of the present invention is added with an external cross-linking agent, and the copolymer has a cross-linked structure. Can be introduced.
External crosslinking agents include polyfunctional isocyanate-based crosslinking agents such as tolylene diisocyanate, trimethylolpropane diisocyanate, diphenylmethane triisocyanate; epoxy-based crosslinking agents such as diglycidyl ether, polyethylene glycol diglycidyl ether, and trimethylolpropane triglycidyl ether Melamine resin crosslinking agent; amino resin crosslinking agent; metal salt crosslinking agent; metal chelate crosslinking agent; peroxide crosslinking agent;
The external cross-linking agent is used to form a cross-linkage within and / or between the molecules of the copolymer by obtaining a copolymer and then adding it to heat treatment or radiation irradiation treatment.

The method for obtaining the heat conductive pressure-sensitive adhesive composition of the present invention from the (meth) acrylic acid ester copolymer (A), the heat conductive inorganic compound (B) and the compound (C) is not particularly limited, and heat conduction The inorganic inorganic compound (B) and the compound (C) may be mixed with a separately synthesized (meth) acrylic acid ester copolymer (A), but the (meth) acrylic acid ester copolymer (A), heat From the viewpoint of uniformly mixing the conductive inorganic compound (B) and the compound (C), the synthesis of the (meth) acrylic acid ester copolymer (A) and the thermally conductive inorganic compound (B) and the compound (C) A method of simultaneously mixing the above is preferred.
When the method of mixing the thermally conductive inorganic compound (B) and the compound (C) with the separately synthesized (meth) acrylic acid ester copolymer (A) is employed, the mixing method is not particularly limited. The dry (meth) acrylic acid ester copolymer (A), the thermally conductive inorganic compound (B) and the compound (C) are mixed with a roll, a Henschel mixer, a kneader, etc. Alternatively, a wet mixing method of mixing in the presence of an organic solvent in a container may be used.
Method of simultaneously synthesizing (meth) acrylic acid ester copolymer (A) and mixing (meth) acrylic acid ester copolymer (A), thermally conductive inorganic compound (B) and compound (C) Is employed, after obtaining a mixture of the copolymer (A1), the monomer mixture (A2m), the thermal polymerization initiator (D2), the thermally conductive inorganic compound (B) and the compound (C). Heating down is preferred. At this time, the mixing order of each component is not particularly limited. Further, it is preferable to carry out the mixing at a temperature at which the polymerization of the monomer mixture (A2m) does not proceed.

The heat conductive pressure-sensitive adhesive composition of the present invention can be formed into a sheet-like molded body.
The sheet-like molded body may be composed of only a heat conductive pressure-sensitive adhesive composition, and is a composite composed of a base material and a heat conductive pressure-sensitive adhesive composition layer formed on one or both sides thereof. There may be.
Although the thickness of the heat conductive pressure-sensitive-adhesive composition layer in the sheet-like molded object of this invention is not specifically limited, Usually, they are 50 micrometers-3 mm. If it is thinner than 50 μm, air is likely to be involved when affixing to the heating element and the radiator, and as a result, sufficient thermal conductivity may not be obtained. On the other hand, if it is thicker than 3 mm, the thermal resistance of the sheet increases and the heat dissipation may be impaired.

When forming a heat conductive pressure sensitive adhesive composition layer in the single side | surface or both surfaces of a base material, a base material is not specifically limited.
Specific examples thereof include foils of metals and alloys having excellent thermal conductivity such as aluminum, copper, stainless steel, and beryllium copper; sheet-like materials made of a polymer having excellent thermal conductivity such as thermal conductive silicone; A heat conductive plastic film containing a heat conductive filler; various nonwoven fabrics; glass cloth; honeycomb structure; and the like can be used. Plastic films include polyimide, polyethylene terephthalate, polyethylene naphthalate, polytetrafluoroethylene, polyether ketone, polyethersulfone, polymethylpentene, polyetherimide, polysulfone, polyphenylene sulfide, polyamideimide, polyesterimide, aromatic polyamide, etc. A film made of a heat-resistant polymer can be used.

The method for producing a sheet-shaped molded article from the heat conductive pressure-sensitive adhesive composition is not particularly limited. For example, on a process paper such as a polyester film which has been subjected to release treatment of the heat conductive pressure-sensitive adhesive composition or a solution thereof. The solvent may be removed by an appropriate method if necessary. Further, the heat conductive pressure sensitive adhesive composition may be formed into a sheet by sandwiching between two exfoliated process papers if necessary and passing between rolls. It is also possible to control the thickness through a die when extruding from the extruder.
In addition, for example, by applying a heat conductive pressure-sensitive adhesive composition or a solution thereof on one or both sides of the substrate and removing the solvent if necessary, the substrate is heated by hot air, an electric heater, infrared rays, or the like. And a thermally conductive pressure-sensitive adhesive composition layer formed on one side or both sides thereof can be obtained.
Moreover, the heat conductive pressure-sensitive-adhesive composition of this invention can also be directly formed on base materials like a heat radiator, and can also be provided as a part of electronic component.

The thermally conductive sheet-like molded product of the present invention is a unit derived from a (meth) acrylic acid ester monomer (a1) that forms a homopolymer having a glass transition temperature of −20 ° C. or lower. The monomer unit (a2) having an organic acid group (0.1 to 20% by weight), the monomer unit (a3) containing a functional group other than the organic acid group (0 to 10% by weight), and copolymerizable therewith 100 parts by weight of the copolymer (A1) containing 0 to 10% by weight of the monomer unit (a4) derived from the monomer, and forming a homopolymer having a glass transition temperature of −20 ° C. or less (meta ) Acrylic acid ester monomer (a5m) 40-100% by weight, monomer having organic acid group (a6m) 60-0% by weight, and monomer copolymerizable therewith (a7m) 0-20% by weight Monomer mixture (A2m) 5 to 70 parts by weight, monomer mixture (A m) 0.1 to 50 parts by weight of thermal polymerization initiator (D2) with respect to 100 parts by weight, and heat conduction with respect to a total of 100 parts by weight of copolymer (A1) and monomer mixture (A2m) It is suitably obtained by mixing, heating and sheeting 70 to 170 parts by weight of the inorganic inorganic compound (B) and 0.05 to 10 parts by weight of the compound (C) having a melting point of 120 to 200 ° C. and a molecular weight of less than 1000. Can do.
According to this method, simultaneously with the formation of the (meth) acrylic acid ester copolymer (A) from the copolymer (A1) and the monomer mixture (A2m), this is a thermally conductive inorganic compound (B) and a compound. A sheet-like molded body of the heat conductive pressure-sensitive adhesive composition uniformly mixed with (C) can be produced. According to this method, the performance of having both the high-temperature adhesive force of the heat-conductive pressure-sensitive adhesive composition sheet-like molded article and the pressure-sensitive adhesive property over a wide temperature range from low temperature to high temperature can be achieved only by heat treatment.

  At this time, the copolymer (A1), the monomer mixture (A2m), the thermal polymerization initiator (D2), the thermally conductive inorganic compound (B) and the compound (C) are mixed under heating, and then the resulting mixture is obtained. (This method is referred to as “Production Method I”), but the copolymer (A1), the monomer mixture (A2m), the thermal polymerization initiator (D2), and the thermally conductive inorganic compound (B ) And the compound (C) are preferably mixed and then sheeted under heating (this method is referred to as “Production Method II”).

In the production method (I), the copolymer (A1), the monomer mixture (A2m), the thermal polymerization initiator (D2), the thermally conductive inorganic compound (B) and the compound (C) are mixed with heating. The obtained (meth) acrylic acid ester copolymer (A), the heat conductive inorganic compound (B) and the compound (C) are uniformly mixed to form a sheet.
The mixing method is not particularly limited, but polymerization of the copolymer (A1) and the monomer mixture (A2m) is performed, and the resulting (meth) acrylic acid ester copolymer (A) and the thermally conductive inorganic compound ( In order to ensure uniform mixing with B) and compound (C), it is preferred to use a powerful mixer. Mixing may be performed batchwise or continuously.
The order of mixing each component is not particularly limited.
Examples of the batch mixer include a high viscosity raw material kneader and a stirrer such as a crusher, a kneader, an internal mixer, and a planetary mixer. Examples of the continuous mixer include a Farrell type continuous kneader in which a rotor and a screw are combined, and a screw type kneader having a special structure. Moreover, the single screw extruder and the twin screw extruder currently used for the extrusion process are mentioned. Two or more of these extruders and kneaders may be combined, or a plurality of machines of the same type may be connected and used. Among these, a twin screw extruder is preferable from the viewpoint of continuity and shear rate.
The heating temperature needs to be a temperature at which the polymerization proceeds smoothly, and is usually in the range of 100 to 200 ° C, preferably 120 ° C to 160 ° C.
The atmosphere at the time of heating and mixing is not particularly limited as long as radical polymerization can proceed.
The method of making the heat conductive pressure-sensitive adhesive composition obtained by heating and mixing into a sheet is not particularly limited, but is a method of passing between rolls sandwiched between process papers, a method of passing a die when extruding from a kneader Etc.

In the production method (II), the copolymer (A1), the monomer mixture (A2m), the thermal polymerization initiator (D2), the thermally conductive inorganic compound (B) and the compound (C) are mixed, and then heated. Into a sheet.
Examples of the mixer for preparing the mixture include the same ones used in the production method (I).
The order of mixing each component is not particularly limited.
The temperature at the time of mixing each component shall be 60 degrees C or less. When mixing is performed at a temperature higher than 60 ° C., the monomer mixture (A2m) starts to be polymerized during mixing and the viscosity is increased, and the subsequent operation becomes difficult.
Next, the mixture of each component is formed into a sheet under heating. Polymerization of the copolymer (A1) and the monomer mixture (A2m) proceeds by heating, and a sheet is formed at the same time to form a thermally conductive sheet-like molded body.
The heating temperature is in the range of 100 ° C to 200 ° C, preferably 120 ° C to 160 ° C. If the temperature is lower than 100 ° C., the polymerization reaction of the monomer mixture (A2m) does not proceed sufficiently, and the high-temperature holding power of the obtained sheet-like molded product may be reduced, causing problems such as generation of odor due to unreacted monomers. There is. If the temperature exceeds 200 ° C., the heat conductive sheet-like molded product may have poor appearance such as color change due to so-called “burn”.
In forming the sheet, it is desirable to apply pressure in order to make the thickness uniform. The pressure condition is usually 10 MPa or less, preferably 1 MPa or less. The pressurization time may be selected in accordance with the temperature conditions and the type / amount of the polymerization initiator to be used, but is preferably within 1 hour in view of productivity.

Hereinafter, the present invention will be described in more detail with reference to examples. Parts and percentages in the examples are by weight unless otherwise specified.
In addition, the evaluation method of each characteristic of a (meth) acrylic acid ester copolymer, a heat conductive pressure-sensitive adhesive composition, and a heat conductive sheet is as follows.
(1) Weight average molecular weight (Mw) and number average molecular weight (Mn) of (meth) acrylic acid ester copolymer
It is determined in terms of standard polystyrene by gel permeation chromatography using tetrahydrofuran as a developing solvent.
(2) Hardness of thermally conductive sheet-like molded body Measured by the Japan Rubber Association Standard (SRIS) Asker C method.
(3) Thermal conductivity of thermally conductive sheet-like molded body It is measured at room temperature with a rapid thermal conductivity meter (QTM-500, manufactured by Kyoto Electronics Industry Co., Ltd.).

(4) Room temperature adhesive strength of thermally conductive sheet-like molded body A test piece of 25 mm × 125 mm is stacked on an aluminum plate, pressed with a 2 kg roller, and left for 1 hour. This sample is set in a thermostatic chamber set at room temperature, and the maximum adhesive strength in the 90-degree direction is measured at a tensile speed of 50 mm / min.
(5) Adhesive strength at 100 ° C. of thermally conductive sheet-like molded body The test is performed in the same manner as the room temperature adhesive strength test except that the temperature of the thermostatic bath is set to 100 ° C.
(6) Easily peelable A test piece of 50 mm × 150 mm is laminated between an aluminum plate and a glass plate of the same size, pressed with a 2 kg roller, and left for 1 hour. Set this sample in a thermostat set at 180 ° C, leave it for 1 hour, immediately insert a scraper with a thickness of 0.5 mm into a test piece bonded between an aluminum plate and a glass plate, and push it in the length direction. To go. At this time, the state of peeling the test piece is observed.
○: The heat dissipation sheet can be easily peeled off from the aluminum plate and the glass plate. It doesn't require much power to peel off.
Δ: The heat-dissipating sheet can be peeled off from the aluminum plate and the glass plate, but force is required to peel off.
X: The heat dissipation sheet cannot be peeled off from the aluminum plate and the glass plate.
(7) Flame retardancy Test in accordance with UL standard UL94 “Flame test method for plastic materials for equipment parts”. A sheet-like sample is put into a cylinder, flame contact is performed for 10 seconds, and immediately after the after-flame combustion stops, a second flame contact for 10 seconds is performed, and the test items shown in Table 1 are evaluated. The test is performed five by five for the same sample type, and the combustion class classification shown in Table 1 is performed based on the result.

(Note to Table 1)
* 1: Maximum value for the 5 samples of the afterflame burning time obtained for each sample * 2: Total value for the 5 samples of the sum of the afterflame burning times obtained for each sample * 3: Maximum value for the 5 samples of the sum of the after flame time and flameless combustion time obtained for each sample. * 4: “None” for all 5 samples.

A reactor was charged with 100 parts of a monomer mixture composed of 94% 2-ethylhexyl acrylate and 6% acrylic acid, 0.03 parts 2,2′-azobisisobutyronitrile and 700 parts ethyl acetate. Then, after substitution with nitrogen, a polymerization reaction was carried out at 80 ° C. for 6 hours. The polymerization conversion rate was 97%. The obtained polymer was dried under reduced pressure to evaporate ethyl acetate to obtain a viscous solid polymer (A1) (1). Mw of polymer (A1) (1) was 280,000, and Mw / Mn was 3.1.
In a mortar for crusher, 100 parts of polymer (A1) (1), butyl acrylate 50.6%, methacrylic acid 11.2%, 2-ethylhexyl acrylate 33.7% and polyethylene glycol dimethacrylate (oxyethylene chain) The monomer mixture (A2m) consisting of 4.5% of NK ester 23G (polyethylene glycol # 1000 dimethacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd. (hereinafter abbreviated as “PEGDMA”) 1) 44.5 parts, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexanone (hereinafter abbreviated as “TMCH”) as a polymerization initiator [1 minute half-life temperature is 149 ° C. 1.6 parts, 3.0 parts of ethylenebisstearic acid amide as compound (C) and 200 parts of aluminum hydroxide were added all at once and sufficiently mixed at room temperature with a crusher. At this time, the weight ratio of aluminum hydroxide to the total of 100 parts of the polymer (A1) (1) and the monomer mixture (A2m) (1) is 138 parts, and the weight ratio of ethylenebisstearic acid amide is 2.1 parts. It becomes. Thereafter, the mixture was defoamed with stirring under reduced pressure to obtain a viscous liquid sample. A polyester film with a release agent was laid on the bottom surface of a mold having a length of 400 mm, a width of 400 mm, and a depth of 2 mm, and then the sample was poured into the mold and covered with a polyester film with a release agent. This was taken out from the mold and polymerized by pressing with a hydraulic press for 30 minutes under the conditions of 130 ° C. and 0.5 MPa, and heat conductive pressure sensitive adhesive covered with polyester film with release agent on both sides An agent composition sheet-like molded body (1) was obtained.
The polymerization conversion rate of the monomer mixture (A2m) was calculated from the amount of residual monomers in the sheet, and found to be 99.9%.
Each characteristic was evaluated about this heat conductive pressure sensitive adhesive composition sheet-like molded object (1). The results are shown in Table 2.

(Comparative Example 1)
A heat conductive pressure-sensitive adhesive composition sheet (2) was obtained in the same manner as in Example 1 except that ethylenebisstearic acid amide was not used. Each characteristic was evaluated about this heat conductive pressure sensitive adhesive composition sheet-like molded object (2). The results are shown in Table 2.

(Note to Table 2)
* 5: Polyethylene glycol dimethacrylate (oxyethylene chain repeat number = approximately 23)
* 6: 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexanone

From the results in Table 2, the following can be understood.
A copolymer (A1), a monomer mixture (A2m), a thermal polymerization initiator (D2), a thermally conductive inorganic compound (B) and a compound (C) are mixed to obtain a mixture, which is thermally conductive under heating. In Example 1 in which a sheet-like molded body was prepared by carrying out sheeting simultaneously with the preparation of the pressure-sensitive adhesive composition, the thermal conductivity was excellent, the adhesive strength in the normal use temperature range was excellent, and at 180 ° C. A sheet-like molded body having easy peelability was obtained.
On the other hand, in the comparative example 1 which did not use a compound (C), it became inferior to easy peelability.

Claims (6)

(Meth) acrylic acid ester monomer-derived unit (a1) forming a homopolymer having a glass transition temperature of −20 ° C. or lower, 80 to 99.9% by weight, a monomer unit having an organic acid group (a2 ) 0.1 to 20% by weight, monomer unit containing a functional group other than organic acid group (a3) 0 to 10% by weight and a monomer unit derived from a monomer copolymerizable therewith (a4) (Meth) acrylic acid ester monomer that forms a homopolymer having a glass transition temperature of −20 ° C. or lower in the presence of 100 parts by weight of copolymer (A1) containing 0 to 10% by weight ( a5m) a monomer mixture (A2m) composed of 40 to 100% by weight, an organic acid group-containing monomer (a6m) 60 to 0% by weight and a monomer copolymerizable therewith (a7m) 0 to 20% by weight ) (Meth) acrylic acid ester obtained by polymerizing 5 to 70 parts by weight Heat comprising 100 parts by weight of copolymer (A), 70 to 170 parts by weight of thermally conductive inorganic compound (B) and 0.05 to 10 parts by weight of compound (C) having a melting point of 120 to 200 ° C. and a molecular weight of less than 1000 Conductive pressure sensitive adhesive composition. The heat conductive pressure-sensitive-adhesive composition of Claim 1 whose said compound (C) is an aliphatic amide compound. The thermally conductive inorganic compound (B) is a metal hydroxide (B1) of Group 2 or Group 13 of the Periodic Table, and the (meth) acrylic acid ester copolymer (A) is foamed. The heat conductive pressure-sensitive adhesive composition according to claim 1 or 2, characterized in that The thermally conductive pressure-sensitive adhesive composition according to claim 3, wherein the expansion ratio is 1.05 to 1.4. The heat conductive sheet-like molded object which consists of a heat conductive pressure-sensitive-adhesive composition of any one of Claims 1-4. The heat conductive sheet-like molded object which consists of a base material and the heat conductive pressure-sensitive-adhesive composition layer of any one of Claims 1-4 formed in the single side | surface or both surfaces.