KR20170017719A - Method of producing heat-radiation insulating sheet, heat-radiation insulating sheet and heat spreader - Google Patents

Abstract

According to an embodiment of the present invention, a method for producing a heat-radiation insulating sheet comprises: a first process of preparing a laminate in which a heat-radiation layer containing a heat-radiation filler and a binder is formed on a first principal plane of a metal layer; a second process of applying a curable resin composition on the surface of the heat-radiation layer of the laminate, curing the same and forming an insulating layer; and a third process of forming an adhesive layer on a second principal plane facing the first principal plane of the metal layer. According to the present invention, heat generated from electronic components or the like can be effectively diffused and radiated.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a heat-dissipating sheet, a heat-dissipating sheet, and a heat spreader,

The present invention relates to a method of manufacturing an insulating sheet, an insulating sheet and a heat spreader. The present application claims priority based on Japanese Patent Application No. 2015-157203 filed on August 7, 2015, the contents of which are incorporated herein by reference.

2. Description of the Related Art In recent years, electronic components such as semiconductor chips, transistors, capacitors, and capacitors, and electric components such as batteries (batteries) have been made more sophisticated. Along with this, the amount of heat generated by electronic parts and electric parts is increasing. When the temperature of an electronic part or an electric part becomes high, the life may be shortened or the reliability may be deteriorated.

For this reason, conventionally, electronic parts and electric parts are provided with a heat sink or a heat spreader for dissipating the heat generated by these parts. As the heat spreader, an adhesive tape is attached to a metal foil having thermal conductivity such as an aluminum foil or a copper foil.

For example, Patent Document 1 discloses a heat-releasing sheet for heat treatment in which a pressure-sensitive adhesive layer and a heat-radiation sheet having a heat radiation layer formed on a layer containing aluminum or an aluminum alloy are laminated.

Japanese Patent Application Laid-Open No. 2005-101025

However, since the heat radiation layer disclosed in Patent Document 1 is made of aluminum or an aluminum alloy coated with alumina, defects may be generated in the alumina layer due to impact or deformation. As the alumina layer is deficient, sufficient insulating property can not be ensured and it is difficult to use in places where insulation is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method of manufacturing an insulating sheet which can be easily bonded to a heating element such as an electronic part, Heat insulating sheet capable of coping with miniaturization and weight reduction and thinning of various electronic parts.

Formation of an insulating layer containing a resin on the heat radiation layer may inhibit heat radiation and is not performed in the ordinary skill of the art. As a result, among those skilled in the art, the formation of a layer on the heat radiation layer has been avoided.

However, as a result of intensive studies, the inventors of the present invention have found that insulating properties can be secured without significantly lowering the thermal diffusibility of the thin film by forming a thin insulating layer uniform on the heat radiation layer by coating.

Further, it has been found that it is possible to provide both a bonding property to a heating element and a thermal conductivity to a heat radiation layer by further providing a predetermined adhesive layer.

That is, the present invention has the following constitution.

(1) A method of manufacturing an insulating sheet according to an aspect of the present invention includes a first step of preparing a laminate having a heat radiation layer containing a heat radiation filler and a binder on a first main surface side of a metal layer, A second step of coating and curing a curable resin composition on the side of the heat radiation layer side of the sieve to form an insulating layer and a third step of forming an adhesive layer on a second main surface opposite to the first main surface of the metal layer Respectively.

(2) The method for producing an insulating sheet according to (1), wherein the curable resin composition comprises a curable resin composition comprising a resin containing a plurality of hydroxyl groups and a polyisocyanate compound, and a resin containing an unsaturated group A curable resin composition, and a curable resin composition comprising a resin containing a hydrolyzable silyl group and an isocyanato group.

(3) The method for producing an insulating sheet according to (2), wherein the resin containing a hydroxyl group is selected from the group consisting of an acrylic resin containing a hydroxyl group, a polyester resin containing a hydroxyl group, and a polyurethane resin containing a hydroxyl group Or one or more selected from the group consisting of

(4) The method for producing an insulating sheet according to (2), wherein the unsaturated group-containing resin is an acrylic resin having an unsaturated group, an epoxy (meth) acrylate resin having an unsaturated group, and a polyurethane resin having an unsaturated group May be at least one selected from the group consisting of

(5) In the method for producing an insulating sheet according to (2), the resin containing the hydrolyzable silyl group and the isocyanato group may be an acrylic resin containing a hydrolyzable silyl group and an isocyanato group.

(6) In the second step of the method for producing an insulating sheet according to any one of (1) to (5), the average thickness of the insulating layer may be 0.1 to 10 탆.

(7) In the second step of the method for producing an insulating sheet according to (6), the average thickness of the insulating layer may be 0.1 m or more and less than 5 m.

(8) In the third step of the method for producing an insulating sheet according to any one of (1) to (5), the average thickness of the adhesive layer may be 5 to 50 탆.

(9) In the first step of the method for producing an insulating sheet according to any one of (1) to (8), the average thickness of the heat radiation layer may be 0.1 to 5 탆.

(10) In the first step of the method for producing an insulating sheet according to any one of (1) to (9), the metal layer may have an average thickness of 3 to 100 탆.

(11) The method for producing an insulating sheet according to any one of (1) to (10), may further comprise a fourth step of further laminating a release sheet on a surface of the adhesive layer opposite to the metal layer.

(12) The heat-insulating sheet according to one aspect of the present invention is characterized in that the heat-insulating sheet has an average thickness of at least 0.1 m and less than 5 m and the curable resin composition comprises an insulating layer containing a cured product, a heat radiation layer containing a heat radiation filler and a binder, , And an adhesive layer are stacked in this order.

(13) In the heat-radiating sheet according to (12), the surface resistivity of the insulating layer may be 1.0 × 10 ⁹ Ω / □ or higher.

(14) A heat spreader according to one aspect of the present invention includes the heat-radiating sheet according to any one of (12) and (13).

The heat-radiating sheet produced by the manufacturing method according to an embodiment of the present invention has good electrical insulation and is easily bonded to a heat-generating body such as an electronic part and is capable of efficiently diffusing heat generated in electronic parts, can do.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram schematically showing a cross section of an insulating sheet according to an embodiment of the present invention; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and it is easily understood by those skilled in the art that various changes can be made in form and details without departing from the spirit and scope of the present invention. Accordingly, the present invention is not construed as being limited to the description of the embodiments described below.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing a cross section of an insulating sheet according to an embodiment of the present invention; FIG. The insulating sheet 10 shown in Fig. 1 has an insulating layer 1, a heat radiation layer 2 containing a heat radiation filler and a binder, a metal layer 3 and an adhesive layer 4 in this order . Prior to use of the heat-radiating sheet 10, the release sheet 5 may be laminated on the exposed surface of the pressure-sensitive adhesive layer 4, if necessary. In addition, another layer may be provided between the layers.

Hereinafter, a method of manufacturing the heat-radiating sheet based on the heat-radiating sheet 10 will be described.

A method of manufacturing an insulating sheet according to an aspect of the present invention includes a first step of preparing a laminate having a heat radiation layer containing a heat radiation filler and a binder on a first main surface side of a metal layer, A second step of applying a curable resin composition on the layer side surface to form an insulating layer and a third step of forming an adhesive layer on a second main surface opposite to the first main surface of the metal layer.

<First Step>

First, a laminate having a heat radiation layer (2) on a first main surface of a metal layer (3) is prepared.

For example, a composition including a heat radiation filler and a binder constituting the heat radiation layer 2 is applied to the first main surface of the metal layer 3 and cured. Thus, a laminate having the heat radiation layer 2 is formed on the first main surface of the metal layer 3.

The composition of the heat radiation filler and the binder may be diluted with a solvent as required and then coated, dried and cured to form the heat radiation layer (2).

As a coating method of the composition including the heat radiation filler and the binder, a coating method capable of forming a thin film having a uniform thickness is preferable.

The average thickness of the heat radiation layer is preferably 0.1 to 5 占 퐉, more preferably 0.5 to 3 占 퐉. If the average thickness of the heat radiation layer is 0.1 to 5 占 퐉, the amount of heat radiation filler in the heat radiation layer can be sufficiently secured, and sufficient heat radiation property can be obtained.

Here, the &quot; average thickness &quot; refers to a value obtained as an arithmetic mean value by measuring the thickness of 10 randomly selected sheets by observing the cross section of the insulating sheet 10. The thickness can be measured by, for example, an electron micrometer (Millitron 1240 manufactured by Seiko EM Limited). Hereinafter, the average thickness of each layer constituting the heat-radiating sheet can be measured by the same means.

The laminate may be prepared by a method other than the method of forming a heat radiation layer by coating as described above. For example, a composition sheet containing a heat radiation filler and a binder may be formed in advance, and the composition sheet may be bonded to the first main surface of the metal layer and cured. A commercially available product in which a heat radiation layer containing a heat radiation filler and a binder is formed on one side of the metal layer may be used as it is.

As the metal layer 3, gold, silver, copper, iron, nickel, aluminum, an alloy including those metals, or the like can be used. It is preferable that the metal is a metal having a high thermal conductivity. From the viewpoints of low cost and easiness of processing, it is preferable to use copper, aluminum, and alloys containing those metals as the metal layer 3.

The average thickness of the metal layer 3 is preferably 3 to 100 占 퐉, more preferably 5 to 80 占 퐉. When the average thickness of the metal layer 3 is 3 탆 or more, the heat-radiating sheet 10 having excellent heat radiation properties can be obtained and the metal layer 3 can be prevented from being distorted or deformed in the step of producing the heat- . When the average thickness of the metal layer 3 is 100 탆 or less, the shape conformability of the heat-radiating sheet 10 to the heat-generating body 10 when the heat-radiating sheet 10 is bonded to the heat-generating body can be sufficiently secured. Therefore, even when the surface of the heat generating element is a curved surface, the contact area between the heat generating element and the insulating sheet 10 can be sufficiently secured, so that the heat of the heat generating element can be efficiently dissipated.

The heat radiation layer (2) contains a heat radiation filler and a binder.

The heat radiation filler used for the heat radiation layer 2 is not particularly limited, irrespective of the metal and the base metal, if the emissivity is 0.8 or more. From the viewpoint of high heat emissivity and low cost, a carbonaceous material is preferable. Examples of the carbonaceous material include carbon black such as acetylene black and ketjen black, graphite, vapor-grown carbon fiber and the like, and one or more of these may be selected and used. The particle diameter of the heat radiation filler preferably has a cumulative mass 50% particle diameter (D50) of 0.1 to 2.0 탆, more preferably 0.2 to 1 탆. When the cumulative mass 50% particle diameter (D50) is in the range of 0.1 to 2.0 占 퐉, a highly smooth heat radiation layer can be obtained.

The binder used for the heat radiation layer 2 is not particularly limited as long as it is a material capable of binding a heat radiation filler. From the viewpoint of the binding property of the heat radiation filler, the coating composition performance of the heat radiation filler and the binder, and the coating performance as the heat radiation layer (2), the binder is preferably a thermosetting or photocurable resin. As the thermosetting resin, for example, an epoxy resin, an oxetane resin, a polysiloxane resin, an unsaturated polyester resin, a vinyl ester resin, a phenol resin, a novolak resin, an amino resin, (Meth) acrylic resins, and polymeric polysaccharides. As the photo-curable resin, for example, an epoxy resin, an oxetane resin, a vinyl ether resin, a polysiloxane resin, a vinyl ester resin and a (meth) acrylic resin can be used.

As the curable resin to be used as the binder, an epoxy resin or a thermosetting epoxy resin or a high-molecular polysaccharide is preferable from the viewpoints of durability and adhesiveness, and it is preferable to use them by crosslinking and curing them with an acid crosslinking agent.

Examples of the epoxy resin include diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, diglycidyl ether of biphenol, and the like, and one or more of them can be used. As the polymer polysaccharide, there may be mentioned one kind or two or more kinds selected from chitosan, chitin and derivatives thereof.

Examples of the acid crosslinking agent include phthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, trimellitic anhydride, tetrahydrophthalic anhydride, pyromellitic anhydride, dodecylsuccinic anhydride, methylnadic anhydride, benzophenone tetracarboxylic anhydride , And anhydrous butane tetracarboxylic acid, and one or more of them can be used.

The content of the heat radiation filler in the heat radiation layer (2) is preferably 20 to 50 mass%, more preferably 30 to 40 mass%. Within this range, there is an advantage in that the heat radiation property is improved by being close to the thermal emissivity of the heat radiating filler. The content of the binder in the heat radiation layer (2) is preferably 50 to 80 mass%, more preferably 60 to 70 mass%. Within this range, there is an advantage that the heat radiation filler is supported on the substrate.

&Lt; Second Step &

In the second step, the curable resin composition is applied to the surface of the laminate on the side of the heat radiation layer (2) and cured to form the insulating layer (1). The insulating layer 1 is formed by coating so that even a thin film can exhibit a sufficient level of insulating property. From the viewpoint of insulation, the thickness of the insulating layer is preferably good, but the thickness of the insulating layer is preferably thin from the viewpoint of heat dissipation. In order to form a uniform insulating layer having a small thickness, it is optimal to form the insulating layer by applying a curable resin composition.

Some commercially available insulating films have a thickness of 10 탆 or less. However, in order to adhere such insulating films to the heat radiation layer 2, an adhesive layer is required and the thickness becomes thicker. Further, it is difficult to adhere the thin insulating film uniformly to the surface of the heat radiation layer 2 without occurrence of wrinkles or mixing of bubbles. That is, it is extremely difficult to form a thin insulating layer having a uniform average thickness of 10 탆 or less by a method other than the application, and a thin insulating layer having a uniform average thickness of less than 5 탆 can not be formed.

The average thickness of the insulating layer 1 formed in the second step is preferably 0.1 mu m or more, more preferably 0.5 mu m or more, and further preferably 1 mu m or more. The average thickness of the insulating layer 1 is preferably 10 占 퐉 or less, more preferably 8 占 퐉 or less, even more preferably less than 5 占 퐉, and particularly preferably 4 占 퐉 or less.

The average thickness of the insulating layer 1 is preferably thin from the viewpoint of heat dissipation as described above, and thick from the viewpoint of insulation. When the average thickness of the insulating layer 1 is 0.1 to 10 占 퐉, sufficient insulating property and high heat radiation property can be maintained. It has been found for the first time by the inventors of the present invention that an insulating layer having an average thickness of less than 5 占 퐉 can be obtained as a ratio by a coating method and that sufficient insulating property can be obtained even with this average thickness.

Here, the sufficient insulating property means that the surface resistance value of the insulating layer 1 is 1.0 x 10 ⁹ ? /? Or more. When the surface resistance value is 1.0 x 10 &lt; ⁹ &gt; [Omega] / square or more, sufficient insulating property is exhibited also in the thickness direction thereof and the heat radiation layer 2 and the metal layer 3 can be prevented from being electrically conducted to the outside through the insulating layer 1 .

Since the insulating layer 1 has a sufficient insulating property, the insulating layer 1 can be used in places where electrical insulation is required in electronic parts and the like.

As the curable resin composition, any known curable resin composition can be used without particular limitation as long as it has electrical insulation.

Specifically, from the viewpoint of curability, a curable resin composition comprising a resin containing a plurality of hydroxyl groups and a polyisocyanate compound, a curable resin composition containing a resin containing an unsaturated group, and a curable resin composition containing a hydrolyzable silyl group and an isocyanato group And a curable resin composition containing a resin which is capable of reacting with a curing agent.

The viewpoint of the curability means that it is possible to cure in a short time by a known method such as thermal curing or light curing.

Hereinafter, this curable resin composition will be described in more detail.

(Curable resin composition comprising a resin containing a plurality of hydroxyl groups and a polyisocyanate compound) < Resin containing a hydroxyl group >

Examples of the base resin of a resin containing a plurality of hydroxyl groups include phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, acrylic resin, polyester resin, polyether resin, Urethane resin, epoxy resin, aminoalkyd resin, silicone resin, and the like, and a plurality of hydroxyl groups are introduced into these.

The resin containing a hydroxyl group is preferably at least one resin selected from the group consisting of an acrylic resin containing a hydroxyl group, a polyester resin containing a hydroxyl group, and a polyurethane resin containing a hydroxyl group. This resin is excellent in curability.

If the insulating layer 1 of the insulating sheet 1 has excellent curability, it is possible to cure in a short time, and an insulating sheet with excellent productivity can be obtained.

The acrylic resin containing a hydroxyl group can be obtained by copolymerizing an acrylic acid ester and / or a methacrylic acid ester with a monomer containing a hydroxyl group. Hereinafter, in the present specification, there is a case where acrylic acid and methacrylic acid are combined to form a (meth) acrylate by combining (meth) acrylate, acrylate and methacrylate together to form (meth) acrylate, acryloyl and methacryloyl .

As the acrylic resin component that becomes the main skeleton of the acrylic resin containing a hydroxyl group, a resin obtained by copolymerizing an acrylic acid ester and / or a methacrylic acid ester can be used.

Examples of the (meth) acrylic esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) Acrylate, stearyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl Hexyl (meth) acrylate, cyclododecyl (meth) acrylate, isobornyl (meth) acrylate and the like.

Examples of the hydroxyl group-containing monomer contained in the copolymerizable component of the acrylic resin containing a hydroxyl group include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) Can be used.

Examples of the polyester resin containing a hydroxyl group include a polyester resin obtained by reacting glycol with dibasic acid, glycol and dibasic acid anhydride, or glycol with dibasic acid lower alkyl ester. The reaction may be any of polycondensation, addition reaction, and transesterification reaction.

At this time, a polyester resin containing a hydroxyl group at the molecular chain end is obtained by reacting the glycol at a ratio in which the hydroxyl group of the glycol is excessive relative to the carboxyl group of the dibasic acid.

More specific examples of the polyester resin include aliphatic glycols such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, decanediol, cyclohexanedimethanol and the like, and aliphatic glycols such as succinic acid, adipic acid, Aliphatic dibasic acids such as succinic acid, fumaric acid, suberic acid, azelaic acid, 1,10-decamethylene dicarboxylic acid, cyclohexanedicarboxylic acid, hexahydroterephthalic acid, hexahydroterephthalic acid, hexahydrophthalic acid and tetrahydrophthalic acid And an aliphatic polyester resin obtained by reacting an aliphatic polyester resin and an anhydride thereof with an aliphatic glycol such as ethylene glycol, propylene glycol and butanediol, and aliphatic glycols such as terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, 4,4'- An aromatic polyester resin obtained by reacting an aromatic dibasic acid such as a carboxylic acid, a diphenylmethane-4,4'-dicarboxylic acid and an anhydride thereof, .

A polyester obtained by adding a small amount of a compound containing 3 to 4 active hydrogen groups such as a hydroxyl group and a carboxyl group in the molecule such as trimethylolpropane, pentaerythritol, trimellitic acid, pyromellitic acid and the like, and anhydrides thereof to glycols or dibasic acids Resin.

The polyurethane resin containing a hydroxyl group can be obtained by reacting a polyisocyanate compound and a compound containing at least two hydroxyl groups in one molecule at a ratio in which the hydroxyl group is excess to the isocyanato group. Examples of the polyisocyanate compound to be used at this time include hexamethylene diisocyanate, toluene diisocyanate, m-xylylene diisocyanate, isophorone diisocyanate, and the like. Examples of the compound containing at least two hydroxyl groups in one molecule include polyether diols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol; Polyolefin diols such as polybutadiene diol, polyisoprene diol, hydrogenated polybutadiene diol and hydrogenated polyisoprene diol; Polyester diols, polycarbonate diols, polycaprolactone diols, silicone diols, diethylene glycol, and the like.

<Polyisocyanate compound>

Examples of the polyisocyanate compound constituting the curable resin composition include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, and hydrogenated compounds thereof, isophorone diisocyanate, hexamethylene diisocyanate Trimethylol propane (TMP) adduct type, buret type, etc., synthesized by a known technique, and compounds having two isocyanato groups in one molecule such as isocyanate, and one or more compounds selected therefrom .

Preferably, at least one compound selected from tolylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate is selected from a trimeric type, a TMP adduct type, and a buret type synthesized by a known technique Is at least one polyisocyanate compound. By selecting these, an insulating layer having excellent strength and toughness can be obtained.

The content of the polyisocyanate compound in the curable resin composition may be optionally determined, but preferably the equivalent ratio of the hydroxyl group of the resin containing a hydroxyl group to the isocyanate group of the polyisocyanate compound (the hydroxyl value of the resin containing a hydroxyl group / the isocyanate group of the polyisocyanate compound Cyanobacteria) is 1 / 0.5 to 1/3. With this blending ratio, an insulating layer excellent in hardenability, strength, toughness, adhesion to a heat radiation layer, and electrical insulation can be obtained. The curing conditions are not particularly limited, but it is preferable to cure at room temperature to 150 ° C for 10 minutes to 12 hours.

(A curable resin composition containing a resin containing an unsaturated group)

The unsaturated group-containing resin is not particularly limited as long as it can be cured by heat or light. Herein, the term "unsaturated group" means a group having an ethylenic carbon-carbon double bond. Specific examples thereof include a vinyl group, an allyl group, and a (meth) acryloyloxy group. (Meth) acrylic resin containing an unsaturated group, an epoxy (meth) acrylate resin containing an unsaturated group, and a polyurethane resin containing an unsaturated group, from the viewpoint of transparency and ease of handling .

As the unsaturated group-containing acrylic resin, an unsaturated group is introduced into a resin obtained by polymerizing a (meth) acrylic acid ester. That is, it is possible to exemplify copolymerization of a carboxyl group or a monomer having a hydroxyl group as a functional group for introducing an unsaturated group into a copolymerization component, followed by addition of a carboxyl group or a monomer having a functional group and an unsaturated group reacting with a hydroxyl group.

Examples of the (meth) acrylic ester used in the unsaturated group-containing (meth) acrylic resin include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) (Meth) acrylate, stearyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobutyl (meth) acrylate, (Meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate and isobornyl (meth) acrylate.

Examples of the monomer having a carboxyl group as a functional group for introducing an unsaturated group in the copolymerization component include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid and crotonic acid. Examples of the monomer having a hydroxyl group include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate.

Examples of the monomer having a functional group and an unsaturated group which react with a carboxyl group or a hydroxyl group used for introducing an unsaturated group into an acrylic resin include an epoxy group-containing monomer or an isocyanato group-containing monomer. Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate and glycidyl allyl ether. Examples of the isocyanato group-containing monomer include 2-isocyanatoethyl (meth) acrylate and 1,1-bis (acryloyloxymethyl) ethyl isocyanate.

Examples of the unsaturated group-containing epoxy (meth) acrylate resin include one or two or more kinds of epoxy resins such as bisphenol epoxy resin, novolac epoxy resin, and 1,6-naphthalene epoxy resin, ) Acrylic acid may be used.

Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol A ethylene oxide addition type epoxy resin, bisphenol A propylene oxide addition type epoxy resin, bisphenol F type epoxy resin, Naphthalene type epoxy resin, and the like. Examples of the novolak-type epoxy resin include epoxy resins obtained by reaction of phenol novolak or cresol novolac with epichlorohydrin or methyl epichlorohydrin. The epoxy resin preferably has an average epoxy equivalent of 150 to 450. By using an epoxy resin having an average epoxy equivalent in this range, it is possible to obtain an epoxy (meth) acrylate which is easy to handle and forms an insulating layer excellent in hardenability, strength, toughness, adhesion to a heat radiation layer and electric insulation.

The reaction of the epoxy resin with (meth) acrylic acid is preferably carried out at a temperature of 60 to 140 캜, more preferably 80 to 120 캜, using an esterification catalyst. If the reaction temperature is less than 60 ° C, the reaction time becomes too long. On the other hand, if it exceeds 140 ° C, the risk of gelation increases.

As the esterification catalyst, known catalysts can be used, and examples thereof include tertiary amines such as triethylamine, N, N-dimethylbenzylamine, N, N-dimethylaniline and diazabicyclooctane; Or diethylamine hydrochloride may be used.

The number average molecular weight of the epoxy (meth) acrylate is preferably 450 to 2500. If the molecular weight is from 450 to 2500, it is easy to handle and the curing reaction proceeds smoothly.

The unsaturated group-containing polyurethane resin can be obtained by the following procedure. For example, a polyisocyanate compound and a polyol having at least two hydroxyl groups in a molecule are reacted at a ratio such that the amount of isocyanato group becomes larger than the amount of hydroxyl group, thereby synthesizing a polyurethane having an isocyanato group. Subsequently, by reacting a compound having a hydroxyl group and a (meth) acryloyl group with a polyurethane having an isocyanato group, a polyurethane containing an unsaturated group can be synthesized.

In addition, a polyurethane resin containing an unsaturated group may be obtained by the following method. First, a polyurethane having two or more hydroxyl groups and a polyisocyanate are reacted in such a ratio that the amount of hydroxyl groups is larger than the amount of isocyanate groups, thereby synthesizing a polyurethane having a hydroxyl group. Subsequently, by reacting a compound having an isocyanato group and a (meth) acryloyl group or a monocarboxylic acid having a (meth) acryloyl group with a polyurethane having a hydroxyl group, a polyurethane containing an unsaturated group is synthesized can do.

Examples of the polyol for synthesizing the unsaturated group-containing polyurethane resin include polyether diols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol; Polyolefin diols such as polybutadiene diol, polyisoprene diol, hydrogenated polybutadiene diol and hydrogenated polyisoprene diol; Polyester diol, polycaprolactone diol, silicone diol, diethylene glycol, and the like.

Examples of the polyisocyanate compound for synthesizing a polyurethane resin containing an unsaturated group include hexamethylene diisocyanate, toluene diisocyanate, m-xylylene diisocyanate, isophorone diisocyanate and the like.

Examples of the compound having a hydroxyl group and (meth) acryloyl group for synthesizing an unsaturated group-containing polyurethane resin include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl Methacrylate, and the like. These may be used in combination of two or more.

The compound having an isocyanato group and a (meth) acryloyl group for synthesizing a polyurethane resin containing an unsaturated group is not particularly limited. For example, 2- (meth) acryloyloxyethyl isocyanate, 1,1-bis (acryloyloxymethyl) ethyl isocyanate and the like can be used. These may be used in combination of two or more.

Examples of the monocarboxylic acid having a (meth) acryloyl group for synthesizing a polyurethane resin containing an unsaturated group include (meth) acrylic acid and? -CEA (? -Carboxyethyl acrylate). These may be used in combination of two or more.

The curable resin composition containing the unsaturated group-containing resin may contain a monomer having a radically polymerizable carbon-carbon double bond as a reactive diluent.

Examples of the monomer having a radically polymerizable carbon-carbon double bond include aromatic unsaturated monomers such as styrene,? -Methylstyrene, vinyltoluene, and divinylbenzene; (Meth) acrylate, diethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, diethyleneglycol di (meth) acrylate, (Meth) acrylate, triethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene glycol di (Meth) acrylate such as polyethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate and pentaerythritol tetra (Meth) acrylic acid esters; Vinyl esters such as vinyl acetate and vinyl propionate; Carboxyl group-containing unsaturated monomers such as (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid half ester and maleic acid half ester; Sulfonic acid group-containing unsaturated monomers such as styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid and sodium styrenesulfonate; Hydroxyl group-containing unsaturated monomers such as hydroxyethyl methacrylate; Cyano group-containing unsaturated monomers such as acrylonitrile and methacrylonitrile; Epoxy group-containing unsaturated monomers such as glycidyl (meth) acrylate and glycidyl allyl ether; Amide group-containing monomers such as (meth) acrylamide and diacetone (meth) acrylamide; Silicone modified unsaturated monomers; And amino group-containing unsaturated monomers such as N, N-dimethylaminoethyl (meth) acrylate. These may be used in combination of two or more.

As the initiator used for curing the curable resin composition containing the unsaturated group-containing resin, any of a thermal polymerization initiator and a photopolymerization initiator may be used.

The thermal polymerization initiator is not particularly limited and may be appropriately selected from known ones. For example, 2,2'-azobisisobutyronitrile, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis Azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis 4,4-trimethylpentane), and dimethyl-2,2'-azobis (2-methylpropionate); Butyl peroxybenzoate, t-butyl hydroperoxide, di-t-butyl peroxide, t-butyl peroxybenzoate, dicumyl peroxide, 1,1-bis (t- And peroxide type thermal polymerization initiators such as cyclohexane and 1,1-bis (t-butylperoxy) cyclododecane.

Examples of the photopolymerization initiator include a photopolymerization initiator such as a carbonyl photopolymerization initiator, a sulfide photopolymerization initiator, a quinone photopolymerization initiator, an azo photopolymerization initiator, a sulfochloride photopolymerization initiator, a thioxanthone photopolymerization initiator, .

Examples of the carbonyl photopolymerization initiator include benzophenone, benzyl, benzoin, omega -bromoacetophenone, chloroacetone, acetophenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy- P, p'-dichlorobenzophenone, p, p'-bisdiethylaminobenzophenone, Michler's ketone, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, 2-chlorobenzophenone, Benzoin isobutyl ether, benzoin-n-butyl ether, benzyl methyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl- 2-methylpropane-1-one, methylbenzoylformate, 2,2-diethoxyacetophenone, 4-N, N'- 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one.

The sulfide-based photopolymerization initiator includes, for example, diphenyl disulfide, dibenzyl disulfide, tetraethyl thiuram disulfide, tetramethyl ammonium monosulfide and the like. Examples of the quinone-based photopolymerization initiator include benzoquinone, anthraquinone, and the like. Examples of the azo-based photopolymerization initiator include azobisisobutyronitrile, 2,2'-azobispropane, hydrazine, and the like.

Examples of the thioxanthene photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, and the like. Examples of the peroxide-based photopolymerization initiator include benzoyl peroxide, di-t-butyl peroxide, and the like.

The polymerization initiators may be used alone or in combination of two or more. The amount of the polymerization initiator to be used may be an ordinary amount, for example, it is preferably in the range of about 0.01 to 5 parts by mass based on 100 parts by mass of the curable resin composition.

(A resin containing a hydrolyzable silyl group and an isocyanato group)

The resin containing a hydrolyzable silyl group and an isocyanato group is not particularly limited so long as it has this group, but from the viewpoints of transparency and ease of handling, it is preferable that the resin is an acrylic resin.

The acrylic resin containing a hydrolyzable silyl group and an isocyanato group can be obtained by copolymerizing an acrylic ester or / and a methacrylate ester with an isocyanato group-containing monomer and a monomer containing a hydrolyzable silyl group. Hereinafter, acrylic and methacrylic are collectively referred to as (meth) acryl.

Examples of the (meth) acrylic esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) Acrylate, stearyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl Hexyl (meth) acrylate, cyclododecyl (meth) acrylate, isobornyl (meth) acrylate and the like.

Examples of the monomer containing a hydrolyzable silyl group to be copolymerized include vinyltriethoxysilane and? - (meth) acryloyloxypropyltrimethoxysilane. Examples of the isocyanato group-containing monomer that can be used include 2-isocyanatoethyl (meth) acrylate and 3-isocyanate propyl (meth) acrylate. The curing conditions are not particularly limited, but it is preferable to cure at room temperature to 150 ° C for 10 minutes to 12 hours.

When these curable resin compositions are applied to the surface of the laminate on the side of the heat radiation layer 2, a known solvent may be contained for adjusting the viscosity and the film thickness.

The method of applying the curable resin composition onto the heat radiation layer 2 and curing it to form the insulating layer 1 is not particularly limited. Examples of the application method include a method using a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, a comma coater, a direct coater and the like. The curing method can be carried out under known heat curing or photo curing conditions according to the composition of the composition. The insulating layer 1 is formed by coating the curable resin composition, drying the solvent if necessary, and then curing the curable resin composition. The thickness of the insulating layer 1 is determined by previously obtaining the viscosity of the curable resin composition or the correlation between the solid content concentration in the curable resin composition and the thickness of the insulating film formed by the coating method and applying the curable resin composition once to obtain a predetermined thickness Or by repeating the application a plurality of times.

<Third Step>

In the third step, the adhesive layer 4 is formed on the second main surface opposite to the first main surface of the metal layer 3. The adhesive layer 4 is a layer for bonding the insulating sheet 10 to a heating element such as an electronic apparatus.

The method of forming the adhesive layer 4 is not particularly limited. For example, the adhesive layer may be formed by applying a pressure-sensitive adhesive diluted with a solvent to one side of the metal layer 3 or the release sheet 5 described later, followed by drying and thermosetting. Alternatively, the pressure-sensitive adhesive sheet may be formed in a sheet form in advance, and the pressure-sensitive adhesive sheet may be bonded to the second main surface of the metal layer. When an adhesive layer is formed by a coating method, a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, a comma coater and a direct coater can be used have.

The average thickness of the pressure-sensitive adhesive layer 4 formed in the third step is preferably 5 to 50 占 퐉, more preferably 8 to 20 占 퐉. When the average thickness of the adhesive layer 4 is 5 占 퐉 or more, the insulating sheet 10 is sufficiently high in bonding strength between the adhesive layer 4 and the heating element and the metal layer 3, If the average thickness of the adhesive layer 4 is 50 m or less, the heat of the heating element can be efficiently conducted to the metal layer 3 through the adhesive layer 4. [

The pressure-sensitive adhesive used for the pressure-sensitive adhesive layer 4 is not particularly limited. A silicone-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, or the like can be used. Among them, it is preferable to use an acrylic pressure-sensitive adhesive in terms of adhesive strength.

The pressure-sensitive adhesive may be a solvent-containing or solvent-free adhesive. For the purpose of enhancing the cohesive force of the pressure-sensitive adhesive, a curing agent according to the pressure-sensitive adhesive may be included. As the curing agent, for example, an isocyanate compound, an epoxy compound, an aziridine compound, a melamine compound and the like can be used.

The adhesive strength of the adhesive layer 4 is preferably not less than 5 N / 25 mm, more preferably not less than 8 N / 25 mm, and even more preferably not less than 10 N / 25 mm, as measured by a measuring method described later . If the adhesive strength of the adhesive layer 4 is 5 N / 25 mm or more, the insulating sheet 10 having a sufficiently high bonding strength between the adhesive layer 4 and the heating element and the metal layer 3 is obtained.

&Quot; Test method of adhesion &quot;

The adhesive force of the adhesive layer 4 is obtained by the following method.

A pressure-sensitive adhesive layer 4 is formed on a substrate using a PET film having a thickness of 50 占 퐉 ("Mirror (registered trademark) S-10" manufactured by Toray Industries, Inc.) as a base material to obtain a test laminate sheet. Subsequently, the test laminated sheet was cut into a size of 25 mm in length and 100 mm in width to obtain a rectangular sheet piece. Subsequently, a rectangular sheet is laminated on a test plate including SUS304, with the adhesive layer facing the test plate. Thereafter, a rectangular sheet was passed through a 2-kg rubber roller (width: about 50 mm) one time, and a test sheet and a rectangular sheet were stuck.

The bonded test plates and rectangular sheets were allowed to stand for 24 hours under an environment of 23 ° C and 50% RH. Thereafter, a tensile test in the direction of 180 DEG is carried out at a peeling speed of 300 mm / min in accordance with JIS Z0237, and the adhesive force (N / 25 mm) of the rectangular sheet to the test plate is measured.

The adhesive layer (4) may contain an insulating thermally conductive filler in the adhesive. The thermally conductive filler may be any material that is insulating and has thermal conductivity. For example, one or two or more kinds of particles selected from metal oxides, metal nitrides and metal hydrates can be mentioned. Examples of the metal oxide include aluminum oxide, magnesium oxide, zinc oxide, titanium dioxide and the like. Examples of the metal nitride include aluminum nitride, boron nitride, silicon nitride and the like. Examples of the metal hydrate include magnesium hydroxide, aluminum hydroxide and the like.

The thermally conductive filler is preferable from the viewpoint that the powder is uniformly dispersed in the adhesive layer 4. The particle diameter of the thermally conductive filler preferably has a cumulative mass of 50% particle diameter (D50) of 1 to 50 mu m, more preferably 3 to 30 mu m. The particle diameter of the thermally conductive filler is preferably set appropriately in accordance with the thickness of the adhesive layer 4. When the cumulative mass 50% particle diameter (D50) is 1 to 50 占 퐉, the contact area between the heat conductive filler contained in the adhesive layer 4 and the heating element and the metal layer 3 is sufficiently obtained, Can efficiently conduct to the metal layer (3) through the metal layer (4).

The &quot; cumulative mass 50% particle diameter (D50) &quot; can be measured using, for example, a laser diffraction particle size distribution measurement using a laser diffraction particle size distribution measuring device of "SALD-200V ER" manufactured by Shimadzu Seisakusho Lt; / RTI &gt;

&Lt; Fourth step &

In the fourth step, the release sheet 5 is further laminated on the surface of the adhesive layer 4 opposite to the metal layer 3. The peeling sheet is not essential for the insulating thermoelectric sheet 10, but is preferably formed for the purpose of facilitating handling such as transportation.

The method of laminating the release sheet 5 is not particularly limited. For example, a laminated sheet can be laminated by laminating a commercially available release sheet to the adhesive layer 4.

As the release sheet 5, for example, a plastic film whose surface has been treated with a release agent can be given.

As the peeling treatment agent, a silicone type, a long chain alkyl type, a fluorine type and the like can be used. Examples of the plastic film include a polyethylene terephthalate (PET) film and the like.

"Insulation sheet"

1, an insulating sheet 10 according to an embodiment of the present invention includes an insulating layer 1, a heat radiation layer 2 containing a heat radiation filler and a binder, a metal layer 3, , And an adhesive layer (4) in this order. The release sheet 5 may be formed on the surface of the adhesive layer 4 opposite to the metal layer 3. [

The heat-radiating sheet 10 preferably has a thermal emissivity of 0.8 to 1, more preferably 0.9 to 1. When the thermal emissivity is 0.8 to 1, sufficient heat radiation is obtained.

The insulating layer 1 is formed by application. The insulating layer 1 having a small thickness can be formed by diluting and applying the above-mentioned curable resin composition to a desired concentration with an appropriate solvent. Specifically, the insulating layer 1 preferably has an average thickness of 0.1 탆 or more, more preferably 1 탆 or more.

The average thickness of the insulating layer 1 is preferably less than 5 占 퐉 and preferably 4 占 퐉 or less.

The insulating layer 1 is an outermost layer when the heat-radiating sheet 10 is attached to a heat generating element such as an electronic component. That is, at the passing point of heat radiated from the heat radiation layer 2 to the outside. If it is originally, there is a fear that the heat radiation property of the heat radiation sheet is deteriorated. However, since the insulating heat-radiating sheet according to one embodiment of the present invention has a very thin layer thickness, the above-described thermal radiation rate can be obtained as the whole of the heat-insulating sheet 10. Since the insulating layer 1 is formed by coating, an extremely thin insulating layer can be obtained. When the film thickness is 0.1 mu m or more, the insulating layer 1 having a surface resistivity of 1.0 x 10 &lt; ⁹ &gt; As a result, it can be used in places where electrical insulation in electronic parts is required.

As the material constituting the insulating layer 1, the above-described materials can be used. By using these materials, it is possible to realize high insulation without significantly deteriorating the heat radiation property.

As the heat radiation layer 2, the metal layer 3, the adhesive layer 4 and the release sheet 5, the same materials and the same constitution as those described above can be applied.

By having the insulating layer 1 as described above, the insulating sheet 10 can maintain high insulation with the outside, and can be used in places where the insulating properties of electronic parts and the like are required.

In addition, since the insulating layer 1 protects the heat radiation layer 2 and the like formed thereunder, the abrasion resistance can also be improved. That is, even if impact or deformation is applied to the heat-radiating sheet 10, the heat radiation property and the insulation property can be maintained.

The heat-radiating sheet 10 can be easily bonded to the heat-generating body and can efficiently dissipate the heat of the heat-generating body. Therefore, the heat-radiating sheet 10 can be suitably used as a heat spreader for heat-dissipating heat generated in the heat-generating body. Examples of the heating element include a semiconductor chip, an electronic component such as a transistor, a capacitor, and a capacitor, an electronic circuit board, a solar battery panel, a lighting device, a display backlight, a projector, an LED light, a signal, A tablet PC, a server, a small game machine, a solar panel memory module, an amplifier, various batteries (battery), and a camera module.

[Example]

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited at all by this example.

&Lt; Synthesis Example 1 (Resin A-1 containing a hydroxyl group) >

(1.82 mol) of butyl acrylate, 621 g (6.20 mol) of ethyl acrylate and 39 g (0.33 mol) of 2-hydroxyethyl acrylate were placed in a reaction vessel equipped with a stirrer, a thermometer, a stirrer, ), 7 g (0.10 mol) of acrylic acid and 0.45 g of 2,2-azoisobutylnitrile were placed and polymerization was carried out at 80 DEG C for 8 hours in a nitrogen gas stream to obtain an acrylic resin (A- 1).

&Lt; Synthesis Example 2 (Resin A-2 containing a hydroxyl group) >

(2.61 mol) of hexahydrophthalic anhydride, 259 g (2.19 mol) of 1,6-hexanediol and 2.19 mol of isocyanuric acid tris (2-hydroxyethyl) phthalate were added to a reaction vessel equipped with a stirrer, ), And the temperature was elevated to 200 DEG C over 2 hours in a nitrogen gas atmosphere. The reaction was carried out under reflux for 8 hours while distilling off water by azeotropic distillation of xylene and water. Thereafter, the mixture was cooled and subsequently diluted with 1000 g of ethyl acetate to obtain a polyester resin (A-2) solution containing a hydroxyl group. The weight average molecular weight of the polyester resin (A-2) containing the hydroxyl group was 5500.

&Lt; Synthesis Example 3 (Resin A-3 Containing a Hydroxyl Group) >

In a reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, and a condenser equipped with a drying tube, 311 g (1.40 mol) of isophorone diisocyanate and a polycarbonate diol, polycarbonate diol having a hydroxyl group having a hydroxyl value of 56 mgKOH / 3000 g (1.50 moles) of T5652 (manufactured by Asahi Kasei Chemicals Co., Ltd., number average molecular weight 2000) and 0.33 g of dioctyltin dilaurate were added, and the temperature was raised to 60 ° C and the reaction was carried out for 4 hours. , Cooled, and subsequently diluted with 1500 g of ethyl acetate to obtain a urethane resin (A-3) containing a hydroxyl group having a weight average molecular weight of 68,000 at the terminal. At this time, after confirming that the peak derived from the isocyanato group disappeared by IR, the reaction was terminated.

&Lt; Synthetic Example 4 (Resin A-4 containing unsaturated group) >

(1.82 mol) of butyl acrylate, 621 g (6.20 mol) of ethyl acrylate and 39 g (0.33 mol) of 2-hydroxyethyl acrylate were placed in a reaction vessel equipped with a stirrer, a thermometer, a stirrer, 7 g (0.10 mol) of acrylic acid and 0.45 g of 2,2-azoisobutylnitrile were placed, and polymerization was carried out at 80 DEG C for 8 hours in a nitrogen gas stream. Subsequently, 51 g (0.33 mol) of 2-isocyanatoethyl methacrylate and 0.01 g of dioctyltin dilaurate were added and the mixture was reacted for 4 hours to obtain an acrylic resin having an unsaturated group having a weight average molecular weight of 630,000 (A- 4).

&Lt; Synthesis Example 5 (Resin A-5 containing unsaturated group) >

180 g (1.0) of phenol novolak type epoxy resin (Epiclon N-740, manufactured by Dainippon Ink and Chemicals, Inc., epoxy equivalent 180) was added to a reaction vessel equipped with a stirrer, a thermometer, a stirrer, (1.0 mol) of acrylic acid, 0.8 g of triphenylphosphine and 0.2 g of methylhydroquinone were charged and reacted at 120 DEG C for 8 hours while blowing a 6% oxygen-94% nitrogen gas mixture, An epoxy acrylate resin (A-5) containing an unsaturated group having a molecular weight of 2800 and an acid value of 1.5 mgKOH / g was obtained.

&Lt; Synthesis Example 6 (Resin A-6 containing unsaturated group) >

A reaction vessel equipped with a thermometer, a stirrer, a dropping funnel and a condenser equipped with a drying tube was charged with 333 g (1.50 mol) of isophorone diisocyanate and D-2000, which is a polypropylene glycol having a hydroxyl group at a hydroxyl value of 56 mgKOH / 2800 g (1.40 mol) of polyoxyethylene (manufactured by Mitsui Chemicals, Inc., number average molecular weight: 2000) and 0.31 g of dioctyltin dilaurate were added, and the mixture was heated to 60 ° C and reacted for 4 hours to give an isocyanato group at the terminal To obtain a polyurethane. Subsequently, 23 g (0.2 mol) of 2-hydroxyethyl acrylate was added, and the mixture was heated to 70 ° C. and reacted for 2 hours to obtain a urethane resin (A-6) containing an unsaturated group having a weight average molecular weight of 70,000 at the terminal . At this time, after confirming that the peak derived from the isocyanato group disappeared by IR, the reaction was terminated.

&Lt; Synthetic Example 7 (Resin A-7 containing hydrolysable silyl group and isocyanato group) >

A reaction vessel equipped with a thermometer, a stirrer, a condenser equipped with a drying tube and a nitrogen inlet tube was charged with 650 g of toluene, 387 g (4.50 mol) of methyl methacrylate, 181 g (1.41 mol) of butyl acrylate, (0.20 mol) of 2-isocyanatoethyl methacrylate and 2.65 g of 2,2-azoisobutylnitrile were charged and polymerization was carried out at 80 DEG C for 8 hours in a nitrogen gas stream, To obtain an acrylic resin (A-7) containing a hydrolyzable silyl group having a weight average molecular weight of 10,000 and an isocyanato group.

(Production of adhesive layer)

, 1 part by mass of an isocyanate-based crosslinking agent (CORONATE HX solid content 100%, manufactured by TOSOH CORPORATION) of 100 parts by mass of an acrylic pressure-sensitive adhesive (Visile (registered trademark) PSA SV-6805 solid content 47% by mass, manufactured by Showa Denko K.K.) And 100 parts by mass of ethyl acetate as a diluting solvent were mixed to prepare a pressure-sensitive adhesive composition. Subsequently, a peeling-treated PET film (trade name: E7006, thickness: 25 mu m, manufactured by TOYOBO CO., LTD.) Was coated with a doctor blade and the solvent was dried to form a pressure-sensitive adhesive layer having a thickness of 10 mu m. Subsequently, peeling PET was covered to obtain a pressure-sensitive adhesive sheet. This pressure sensitive adhesive sheet becomes a pressure sensitive adhesive layer by adhering to a metal layer to be described later.

&Lt; Preparation of Insulation Heat-Release Sheet &

(Example 1)

100 parts by mass of the acrylic resin (A-1) obtained in Synthesis Example 1 and 100 parts by mass of a polyisocyanate compound (isocyanurate of hexamethylene diisocyanate (HDI), Coronate (registered trademark) HX manufactured by Tosoh Corporation, solid content 100%), and toluene was further blended to prepare a curable resin composition having a nonvolatile content of 30% by mass. This curable resin composition was applied on a carbon coating layer of a carbon-coated aluminum metal sheet (Showa Denko KK: carbon coated aluminum foil, SDX (registered trademark)) having a heat radiation layer (carbon coating layer) and a metal layer To a thickness of 20 탆, and dried at 150 캜 for 10 minutes to form an insulating layer. The average thickness of the insulating layer at this time was 4 占 퐉.

The heat radiation layer is obtained by crosslinking carbon black as a heat radiation filler and chitosan derivative as a binder with pyromellitic acid. The average thickness of the heat radiation layer is 1 mu m, and the metal layer is an aluminum foil having an average thickness of 50 mu m. The thicknesses of the insulating layer and the heat radiation layer were measured with an electron micrometer (Millitron 1240, manufactured by Seiko EM Corporation) at 10 points, and the average value thereof was determined.

Then, the heat-sensitive insulating sheet B-1 of Example 1 was obtained by bonding the pressure-sensitive adhesive sheet having a thickness of 10 mu m from which the peel-off PET film was removed to the metal layer surface of the laminated sheet.

(Example 2)

Heat-insulating sheet B-2 of Example 2 was obtained in the same manner as in Example 1 except that the curable resin composition for forming the insulating layer was changed.

The curable resin composition of Example 2 was obtained by mixing 100 parts by mass of the polyester resin (A-2) obtained in Synthesis Example 2 and 100 parts by mass of a polyisocyanate compound (Coronate (registered trademark) HX, solid content 100% 11.0 parts by mass were mixed, and the content of non-volatile components was adjusted to 30% with toluene.

(Example 3)

Heat-insulating sheet B-3 of Example 3 was obtained in the same manner as in Example 1 except that the curable resin composition for forming the insulating layer was changed.

The curable resin composition of Example 3 was obtained by mixing 100 parts by mass of the urethane resin (A-3) obtained in Synthesis Example 3 and 2.0 parts by mass of a polyisocyanate compound (CORONATE (registered trademark) HX, solid content 100% And toluene was added thereto to adjust the non-volatile content to 30%.

(Example 4)

100 parts by mass of the acrylic resin (A-4) obtained in Synthetic Example 4 and 0.5 parts by mass of 1-hydroxycyclohexyl phenyl ketone (Irgacure (registered trademark) 907, manufactured by BASF) were further blended with toluene And a nonvolatile matter content of 30 mass% was prepared. The curable resin composition thus prepared was coated on a carbon coating layer of a carbon-coated aluminum metal sheet (manufactured by Showa Denko K.K., carbon coated aluminum foil SDX (registered trademark)) having a heat radiation layer and a metal layer to a thickness of 20 μm using a bar coater, Lt; 0 &gt; C for 5 minutes. Subsequently, the upper surface was covered with a peelable PET film having a thickness of 50 mu m, and then an ultraviolet ray irradiator (UV irradiator: 4 kw x 1, output: 160 W / cm, metal halide lamp, manufactured by Nippon Denshi K.K.) A lamp moving speed of 20 m / min, and an irradiation dose of about 1000 mJ / cm 2 to form an insulating layer having an average thickness of 4 탆.

The heat radiation layer is obtained by crosslinking carbon black as a heat radiation filler and chitosan derivative as a binder with pyromellitic acid. The average thickness of the heat radiation layer is 1 mu m, and the metal layer is an aluminum foil having an average thickness of 50 mu m.

Next, an adhesive sheet of 10 mu m in thickness with one of the peelable PET films removed was bonded to the metal layer surface of the laminated sheet to obtain an insulating sheet B-4 of Example 4. [

(Example 5)

Heat-insulating sheet B-5 of Example 5 was obtained in the same manner as in Example 4 except that the curable resin composition for forming the insulating layer was changed.

The curable resin composition of Example 5 was obtained by mixing 100 parts by mass of the epoxy acrylate resin (A-5) obtained in Synthesis Example 5 and 1 part by mass of 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure (registered trademark) 907 ), And further toluene was added to adjust the nonvolatile content to 30%.

(Example 6)

Heat-insulating sheet B-6 of Example 6 was obtained in the same manner as in Example 4 except that the curable resin composition for forming the insulating layer was changed.

The curable resin composition in Example 6 was prepared by mixing 100 parts by mass of Resin A-6 obtained in Synthesis Example 6 and 0.5 parts by mass of 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure (registered trademark) 907, And further toluene was added to adjust the nonvolatile content to 30%.

(Example 7)

Toluene was blended with the acrylic resin (A-7) obtained in Synthesis Example 7 to prepare a curable resin composition having a nonvolatile content of 30 mass%, and a carbon-coated aluminum metal sheet having a heat radiation layer and a metal layer (Showa Denko KK: SDX (registered trademark)) to a thickness of 20 mu m using a bar coater, and dried at room temperature for 3 hours to form an insulating layer.

The heat radiation layer is obtained by crosslinking carbon black as a heat radiation filler and chitosan derivative as a binder with pyromellitic acid. The average thickness of the heat radiation layer is 1 mu m, and the metal layer is an aluminum foil having an average thickness of 50 mu m.

Next, an adhesive sheet of 10 mu m in thickness, from which the peel-off PET film was removed, was bonded to the surface of the metal layer of the laminated sheet to obtain an insulating sheet B-7 of Example 7. [

(Example 8)

Heat-radiating sheet B-8 of Example 8 was obtained in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive sheet of Example 1 was changed to 3 占 퐉.

(Example 9)

The heat radiation sheet B-9 of Example 9 was obtained in the same manner as the insulation heat radiation sheet of Example 1 except that the amount of toluene to be compounded was increased to change the non-volatile content of the resin solution to 5%.

(Comparative Example 1)

Heat-radiating sheet C-1 of Comparative Example 1 was obtained in the same manner as in Example 1 except that the insulating layer 1 of Example 1 was omitted.

(Comparative Example 2)

Heat-insulating sheet C-2 of Comparative Example 2 was obtained in the same manner as in Example 1 except that the heat radiation layer (2) of Example 1 was excluded.

(Comparative Example 3)

Heat-insulating sheet C-3 of Comparative Example 3 was obtained in the same manner as in Example 1 except that the adhesive layer (4) of Example 1 was excluded.

(Comparative Example 4)

The insulating layer of Example 1 was coated with a 50 mu m thick PET film (manufactured by Toray Industries, Inc., &quot; Lumirror &quot;, manufactured by Toray Industries, Inc.) Heat-resistant sheet C-4 of Comparative Example 4 was obtained in the same manner as in the case of the heat-radiating sheet of Example 1, except that the surface of the heat-radiating sheet 2 was changed to " .

(Evaluation of electric insulation)

The surface resistivity of each of the heat-dissipating sheets of Examples 1 to 9 and Comparative Examples 1 and 2 was measured, and the obtained results were evaluated as follows.

Electrical Insulation ⊚: 1.0 × 10 ¹⁴ Ω / □ or more

Electrical Insulation ◯: 1.0 × 10 ⁹ to 1.0 × 10 ¹⁴ Ω / □

Electrical insulation x: Less than 1.0 x 10 ⁹ ? /?

For each of the heat-radiating sheets of Examples 1 to 9 and Comparative Examples 1 and 2, the adhesive strength was determined by the following method.

&Quot; Test method of adhesion &quot;

The heat-radiating sheet is cut to a size of 25 mm in length and 100 mm in width to form a rectangular sheet. Subsequently, a rectangular sheet is laminated on the test plate including SUS304 with the adhesive layer facing the test plate. Thereafter, a rectangular sheet was passed through a 2-kg rubber roller (width: about 50 mm) one time, and a test sheet and a rectangular sheet were stuck. Subsequently, the bonded test plates and the rectangular sheet are left for 24 hours in an environment of 23 ° C and a humidity of 50% RH. Thereafter, according to JIS Z0237, a tensile test in the direction of 180 占 is carried out at a peeling speed of 300 mm / min, and the adhesive force (N / 25 mm) of the rectangular sheet to the test plate is measured.

Heat dissipation properties of each of the insulating heat-dissipating sheets of Examples 1 to 9 and Comparative Examples 1 and 2 were evaluated by the following methods.

&Quot; Evaluation method of heat dissipation &quot;

A heat-insulating sheet with a square of 60 mm in length and 60 mm in width was peeled from both sides of a square ceramic heater (WALN-1, manufactured by Sakaguchi Dentetsu Co., Ltd.) having a length of 60 mm and a width of 60 mm, Layers were stacked facing each other. Then, the heater temperature (after 60 minutes) when the ceramic heater was heated to 5 W was measured, and the heat radiation performance was evaluated. The evaluation was carried out in an environment of a room temperature of 25 DEG C and a humidity of 50% RH.

Further, when the ceramic heater in a state in which the insulating sheet was not attached was heated to 5 W, the heater temperature was 150 캜.

1: insulating layer
2:
3: metal layer
4: Adhesive layer
5: peeling sheet
10: Insulation sheet

Claims (14)

A first step of preparing a laminate having a heat radiation layer containing a heat radiation filler and a binder on a first main surface side of a metal layer;
A second step of applying and curing a curable resin composition on the side of the heat radiation layer of the laminate to form an insulating layer,
And a third step of forming an adhesive layer on a second main surface opposite to the first main surface of the metal layer. The curable resin composition according to claim 1, wherein the curable resin composition comprises a curable resin composition comprising a resin containing a plurality of hydroxyl groups and a polyisocyanate compound, a curable resin composition comprising a resin containing an unsaturated group, and a curable resin composition comprising a hydrolyzable silyl group and isocyanate Wherein the curable resin composition comprises a curable resin composition containing a resin containing earthenware. The heat-insulating sheet according to claim 2, wherein the resin containing a hydroxyl group is at least one selected from the group consisting of an acrylic resin containing a hydroxyl group, a polyester resin containing a hydroxyl group, and a polyurethane resin containing a hydroxyl group Gt; The heat-resistant sheet according to claim 2, wherein the resin containing the unsaturated group is at least one selected from the group consisting of an acrylic resin having an unsaturated group, an epoxy (meth) acrylate resin having an unsaturated group, and a polyurethane resin having an unsaturated group &Lt; / RTI &gt; 3. The method of producing an insulation sheet according to claim 2, wherein the resin containing the hydrolyzable silyl group and the isocyanato group is an acrylic resin containing a hydrolyzable silyl group and an isocyanato group. The method of manufacturing an insulating sheet according to claim 1, wherein the insulating layer has an average thickness of 0.1 to 10 탆 in the second step. The method of manufacturing an insulating sheet according to claim 6, wherein the average thickness of the insulating layer in the second step is 0.1 탆 or more and less than 5 탆. The method of manufacturing an insulating sheet according to claim 1, wherein the adhesive layer has an average thickness of 5 to 50 탆 in the third step. The method of manufacturing an insulating sheet according to claim 1, wherein in the first step, the average thickness of the heat radiation layer is 0.1 to 5 占 퐉. The method of manufacturing an insulating sheet according to claim 1, wherein the metal layer has an average thickness of 3 to 100 占 퐉 in the first step. The method of manufacturing an insulating sheet according to claim 1, further comprising a fourth step of further laminating a release sheet on a surface of the adhesive layer opposite to the metal layer. Wherein the curable resin composition has an average thickness of 0.1 占 퐉 or more and less than 5 占 퐉, an insulating layer containing a cured product, a heat radiation layer containing a heat radiation filler and a binder, a metal layer, and an adhesive layer, Sheet. 13. The heat-insulating sheet according to claim 12, wherein the insulating layer has a surface resistivity of 1.0 x 10 &lt; ⁹ &gt; A heat spreader comprising the heat-radiating sheet according to claim 12.

Images