WO2022097442A1

WO2022097442A1 - Adhesive film, adehsive film with support sheet, cured body and method for producing structure

Info

Publication number: WO2022097442A1
Application number: PCT/JP2021/038057
Authority: WO
Inventors: 功市川; 毅朗吉延
Original assignee: リンテック株式会社
Priority date: 2020-11-04
Filing date: 2021-10-14
Publication date: 2022-05-12
Also published as: KR20230098130A; TW202229489A; JPWO2022097442A1; CN116348564A

Abstract

An adhesive film 1 which is formed of an adhesive resin composition that contains (A) a thermally conductive filler that is composed of at least one of a graphene having a two-dimensional structure and a single-walled boron nitride, (B) a thermosetting component and (C) a binder polymer, and which is used in a heating process that comprises a preliminary heating step and a complete curing step wherein the adhesive film 1 is completely cured after the preliminary heating step. In the preliminary heating step, the adhesive film 1 is held at a temperature that is not more than the temperature (T) descried below for 30 minutes or more.　Temperature (T): a temperature at which the adhesive film 1 has a 0.5% weight loss if an adhesive film 1 before an arbitrary heating process is subjected to a thermogravimetric measurement wherein the adhesive film 1 is heated from 40°C to 400°C at a heating rate of 10°C/minute in the ambient atmosphere　This adhesive film 1 exhibits excellent thermal conductivity.

Description

Method for manufacturing adhesive film, adhesive film with support sheet, cured product, and structure

The present invention relates to an adhesive film having excellent thermal conductivity and a method for producing the same, an adhesive film with a support sheet, a cured product and a method for producing the same, and a method for producing a structure.

Conventionally, in electronic devices such as thermoelectric conversion devices, photoelectric conversion devices, and semiconductor devices such as large-scale integrated circuits, heat-dissipating members having thermal conductivity have been used in order to dissipate heat generated. For example, as a method for efficiently radiating heat generated from a semiconductor device to the outside, a sheet-shaped heat radiating member (film, sheet) having excellent thermal conductivity is provided between the semiconductor device and the heat sink. ing.

As exemplified in Patent Document 1, the above-mentioned film or sheet is coated with a coating liquid of a heat-dissipating material containing an adhesive resin, an inorganic filler, a curing agent and a solvent on a release sheet or a base material. Manufactured by drying. As the inorganic filler, silica, alumina, glass, titanium oxide and the like are used.

JP-A-2015-67713

However, conventional films and sheets containing inorganic fillers may not always obtain the desired thermal conductivity. Therefore, those having further excellent thermal conductivity are required. Here, when a conventional film or sheet containing an inorganic filler is highly filled with the inorganic filler in order to obtain high thermal conductivity, it becomes mechanically brittle, its flexibility is lowered, and broken debris is generated during use. In some cases, problems in the process may occur. In addition, the surface roughness of the sheet-shaped heat-dissipating member becomes large, which makes it difficult for tack to occur, and temporary adhesiveness may not be obtained when the sheet-shaped heat-dissipating member is attached to the adherend, or the sheet-shaped heat-dissipating member is covered. When affixed to the body, it becomes easy for air to be entrained, and many voids are created at the adhesive interface between the sheet-shaped heat dissipation member and the adherend and inside the sheet-shaped heat radiation member, which may reduce thermal conductivity. ..

The present invention has been made in view of such an actual situation, and provides an adhesive film having excellent thermal conductivity and a method for producing the same, an adhesive film with a support sheet, a cured product and a method for producing the same, and a method for producing a structure. The purpose is to provide.

In order to achieve the above object, firstly, the present invention comprises a heat conductive filler (A) composed of at least one of a graphene having a two-dimensional structure and a single-layer boron nitride, a heat-curable component (B), and a heat-curable component (B). An adhesive film made of an adhesive resin composition containing a binder polymer (C), which is subjected to a heat treatment including a preheating step and a complete curing step of completely curing the adhesive film after the preheating step. (Invention 1), wherein the preheating step is a step of holding the preheating step at a temperature of the following temperature (T) or lower for 30 minutes or more (Invention 1).
Temperature (T): The adhesive film before any heat treatment was subjected to thermal weight measurement under the condition of raising the temperature from 40 ° C. to 400 ° C. at a heating rate of 10 ° C./min under an atmospheric atmosphere, and the adhesive film was measured. The temperature at which the weight is reduced by 0.5%.

The adhesive film according to the above invention (Invention 1) has excellent thermal conductivity by containing the above-mentioned specific heat conductive filler (A) and by using it in the above-mentioned applications.

Secondly, the present invention contains a thermally conductive filler (A) composed of at least one of a graphene having a two-dimensional structure and a single-layer boron nitride, a thermosetting component (B), and a binder polymer (C). An adhesive film made of an adhesive resin composition, wherein the area ratio of the void portion in the thickness direction cross section of the cured product obtained by heat-treating the adhesive film under the following conditions is 10% or less. (Invention 2).
(conditions)
The heat treatment includes a preheating step and a complete curing step of completely curing the adhesive film after the preheating step, and the preheating step includes an atmospheric atmosphere for the adhesive film before any heat treatment. A step of holding the adhesive film at a temperature equal to or lower than a temperature at which the weight of the adhesive film is reduced by 0.5% for 30 minutes or more when the thermal weight is measured under the condition that the temperature is raised from 40 ° C. to 400 ° C. at a heating rate of 10 ° C./min. Is.

The adhesive film according to the above invention (Invention 2) is used by containing the above-mentioned specific heat conductive filler (A) and by heat-treating under the above-mentioned conditions to obtain the above-mentioned cured product. , It has excellent thermal conductivity.

In the above inventions (Inventions 1 and 2), the content of the thermally conductive filler (A) is preferably 5% by mass or more and 60% by mass or less (Invention 3).

In the above inventions (Inventions 1 to 3), the thermosetting component (B) is preferably an epoxy resin (Invention 4).

In the above inventions (inventions 1 to 4), it is preferable that the invention is hot-pressed (invention 5).

In the above inventions (Inventions 1 to 5), it is preferable that the arithmetic average roughness (Ra) of at least one surface is 0.01 μm or more and 0.5 μm or less (Invention 6).

Thirdly, the present invention further comprises mixing a thermally conductive filler (A) consisting of at least one of graphene and single-layer boron nitride having a two-dimensional structure and a binder polymer (C) in a solvent. Provided is a method for producing an adhesive film, which comprises obtaining an adhesive resin composition by mixing a thermosetting component (B) and forming the obtained adhesive resin composition into a film. (Invention 7).

In the above invention (Invention 7), it is preferable to form the adhesive resin composition into a film and then heat-press it (Invention 8).

In the above invention (Invention 8), it is preferable that the heating temperature of the hot press is lower than the curing reaction temperature of the thermosetting component (B) (Invention 9).

In the above inventions (Inventions 8 and 9), the arithmetic mean roughness (Ra) of at least one surface of the adhesive film after hot pressing is preferably 0.01 μm or more and 0.5 μm or less (invention). 10).

Fourth, the present invention provides an adhesive film with a support sheet including the adhesive film (inventions 1 to 6) and a support sheet laminated on at least one surface side of the adhesive film (invention 11).

Fifth, the present invention contains a thermally conductive filler (A) composed of at least one of graphene and single-layer boron nitride having a two-dimensional structure, a thermosetting component (B), and a binder polymer (C). Provided is a cured product obtained by subjecting an adhesive film made of an adhesive resin composition to be heat-treated, wherein the area ratio of the void portion in the cross section in the thickness direction is 10% or less. (Invention 12).

In the above invention (Invention 12), it is preferable that the maximum area of the void portion in the cross section in the thickness direction is 100 μm ² or less (Invention 13).

In the above inventions (Inventions 12 and 13), the heat treatment includes a preheating step and a complete curing step of completely curing the adhesive film after the preheating step, and the preheating step is an arbitrary heat treatment. The weight of the adhesive film is reduced by 0.5% when the thermal weight measurement is performed under the condition that the temperature of the adhesive film is raised from 40 ° C. to 400 ° C. at a temperature increase rate of 10 ° C./min in an air atmosphere. It is preferable to include a step of holding the film at a temperature equal to or lower than the temperature for 30 minutes or more (Invention 14).

Sixth, the present invention contains a thermally conductive filler (A) composed of at least one of graphene and single-layer boron nitride having a two-dimensional structure, a thermosetting component (B), and a binder polymer (C). A method for producing a cured product, which comprises heat-treating an adhesive film made of an adhesive resin composition to form a cured product. The heat treatment completely completes the adhesive film after a preheating step and a preheating step. The preheating step includes a complete curing step of curing, and the preheating step is a condition in which the temperature of the adhesive film before any heat treatment is raised from 40 ° C. to 400 ° C. at a heating rate of 10 ° C./min under an air atmosphere. The present invention provides a method for producing a cured product, which comprises a step of holding the adhesive film at a temperature equal to or lower than a temperature at which the weight is reduced by 0.5% by 0.5% for 30 minutes or more when a thermal weight measurement is performed (Invention 15).

In the above invention (invention 15), it is preferable to heat-press the adhesive film before the heat treatment (invention 16).

In the above inventions (inventions 15 and 16), the area ratio of the void portion in the thickness direction cross section of the cured product is preferably 10% or less (invention 17).

Seventh, the present invention contains a heat conductive filler (A) composed of at least one of a graphene having a two-dimensional structure and a single-layer boron nitride, a heat-curable component (B), and a binder polymer (C). A bonding step of bonding at least a part of the first member to at least a part of the second member via an adhesive film made of an adhesive resin composition, and heating the adhesive film after the bonding. A step of obtaining a structure in which at least a part of the first member and at least a part of the second member are bonded via the cured body by treating the cured body. The heat treatment includes a preheating step and a complete curing step of completely curing the adhesive film after the preheating step, and the adhesive film before the preheating step performs an arbitrary heat treatment. 30 minutes at a temperature below the temperature at which the adhesive film loses 0.5% by weight when the thermal weight is measured under the condition that the temperature rises from 40 ° C to 400 ° C at a heating rate of 10 ° C / min under an air atmosphere. Provided is a method for manufacturing a structure, which comprises the above-mentioned holding step (Invention 18).

In the above invention (Invention 18), it is preferable to heat-press the adhesive film before the heat treatment (particularly before the bonding step) (Invention 19).

In the above inventions (inventions 18 and 19), the area ratio of the void portion in the cross section in the thickness direction of the cured product is preferably 10% or less (invention 20).

In the above inventions (Inventions 18 to 20), in the bonding step, at a temperature equal to or higher than the temperature showing the peak of loss tangent (tan δ) obtained by measuring the viscoelasticity of the adhesive film before any heat treatment. It is preferable to perform the bonding (Invention 21).

In the above inventions (Inventions 18 to 20), the first member is a flexible sheet-like member, and a laminate of the sheet-like member and the heat-pressed adhesive film is used as the second member. It is preferable to perform the bonding at a temperature equal to or higher than the temperature showing the peak of loss tangent (tan δ) obtained by measuring the viscoelasticity of the adhesive film before any heat treatment. ..

The inventions (Inventions 18 to 20) include a step of attaching the adhesive film to the first member or the second member, and have viscoelasticity of the adhesive film before any heat treatment. It is preferable to perform the pasting at a temperature equal to or higher than the temperature indicating the peak of the loss tangent (tan δ) obtained by the measurement.

The adhesive film, the adhesive film with a support sheet, the cured body and the structure according to the present invention are excellent in thermal conductivity. Further, according to the method for producing an adhesive film according to the present invention, it is possible to produce an adhesive film having excellent thermal conductivity. Further, according to the method for producing a cured product according to the present invention, a cured product having excellent thermal conductivity can be produced, and according to the method for producing a structure according to the present invention, a structure having excellent thermal conductivity can be produced. The body can be manufactured.

It is sectional drawing of the adhesive film with a support sheet which concerns on one Embodiment of this invention. It is sectional drawing of the structure which concerns on one Embodiment of this invention. It is an image of the cross section in the cured body (Example 1) of the adhesive film by a scanning electron microscope (SEM). An image of a cross section of a cured body (Example 1) of an adhesive film obtained by a scanning electron microscope (SEM) is binarized. It is an image of the cross section in the cured body (Comparative Example 2) of the adhesive film by the scanning electron microscope (SEM). This is a binarized image of a cross section of a cured product (Comparative Example 2) of an adhesive film obtained by a scanning electron microscope (SEM).

Hereinafter, embodiments of the present invention will be described.
[Adhesive film]
The adhesive film according to the present embodiment includes a thermally conductive filler (A) composed of at least one of graphene and single-layer boron nitride having a two-dimensional structure, a thermosetting component (B), and a binder polymer (C). It is made of an adhesive resin composition containing the above (hereinafter, may be referred to as "adhesive resin composition R"). The adhesive resin composition R preferably contains a curing agent (D), and more preferably contains a curing accelerator (E).

The adhesive film according to the present embodiment is first used to perform a heat treatment including a preheating step and a complete curing step of completely curing the adhesive film after the preheating step. It is preferable to include a step of holding at a temperature of the following temperature (T) or less for 30 minutes or more. By performing such a heat treatment, the number of voids is reduced inside the obtained cured product. Specifically, the area ratio of the void portion in the cross section in the thickness direction of the obtained cured product can be 10% or less. Details regarding the heat treatment will be described later.
Temperature (T): For the adhesive film before any heat treatment, the thermal weight was measured under the condition that the temperature was raised from 40 ° C to 400 ° C at a temperature rising rate of 10 ° C / min under the atmospheric atmosphere, and the adhesive film was released. Temperature that reduces weight by 0.5%.

Secondly, in the adhesive film according to the present embodiment, the area ratio of the void portion in the cross section in the thickness direction of the cured product obtained by heat-treating the adhesive film under the following conditions is 10% or less. preferable.
(conditions)
The heat treatment includes a preheating step and a complete curing step of completely curing the adhesive film after the preheating step.
In the preheating step, the adhesive film before any heat treatment is subjected to thermal weight measurement under the condition of raising the temperature from 40 ° C. to 400 ° C. at a heating rate of 10 ° C./min in an air atmosphere. This is a step of holding the film at a temperature lower than the temperature at which the weight is reduced by 0.5% for 30 minutes or more.

The thermally conductive filler (A) composed of at least one of graphene and single-layer boron nitride having a two-dimensional structure has a characteristic of having a large specific surface area because it has a two-dimensional structure having a thickness on the order of several tens of nm. Therefore, in the adhesive film, the heat conductive fillers (A) are in contact with each other, and a heat conduction path for transferring heat is likely to be formed. In particular, by performing the predetermined heat treatment as described above and using the cured product, the voids inside the obtained cured product can be reduced, whereby even a small amount of the heat conductive filler (A) added is excellent. It can show thermal conductivity. That is, when the heat conductive filler (A) is used as a filler for the adhesive resin composition, excellent heat conductivity can be imparted without high filling. Further, since the above-mentioned heat conductive filler (A) has a two-dimensional structure having a thickness on the order of several tens of nm and has flexibility in itself, the adhesive film containing the heat conductive filler (A) can be used. , It will be excellent in flexibility. Moreover, since it is not necessary to highly fill the thermally conductive filler (A) as described above, the adhesive film is prevented from becoming mechanically brittle.

If the adhesive film has excellent flexibility, it becomes difficult for air to be entrained when the adhesive film is attached to the adherend, and it is possible to suppress the formation of voids at the interface between the adhesive film and the adherend, and to reduce the contact area between the adhesive film and the adherend. Can be made larger. That is, it is possible to suppress the increase in thermal resistance due to the voids at the interface between the adhesive film and the adherend, and it is possible to improve the thermal conductivity between the adhesive film and the adherend. Further, if the adhesive film is prevented from becoming mechanically brittle as described above, the probability of occurrence of process defects such as generation of broken debris during use is reduced.

Furthermore, if a conventional inorganic filler is highly filled in order to obtain the desired thermal conductivity, the surface roughness of the adhesive film becomes large and tack becomes difficult to develop. On the other hand, since the heat conductive filler (A) in the present embodiment can obtain high heat conductivity without being highly filled as described above, the surface roughness of the adhesive film can be lowered, thereby lowering the surface roughness. When the adhesive film is attached to the adherend, the appropriate adhesive force can be exhibited by adjusting the attachment temperature.

1. 1. Each component (1) Thermally conductive filler (A)
The thermally conductive filler (A) in the present embodiment comprises at least one of graphene having a two-dimensional structure and monolayer boron nitride. Graphene has a two-dimensional structure in which carbon atoms are regularly arranged in a hexagon, and single-layer boron nitride has a two-dimensional structure in which boron atoms and nitrogen atoms are regularly arranged in a hexagon. It is a dimensional compound. The “graphene or single-layer boron nitride having a two-dimensional structure” in the present specification may be a multi-layered one, preferably having a thickness of 1/10 or less of the shortest length in a plan view shape. It should be noted that graphene in the present specification includes those produced by thinly peeling graphite, and single-layer boron nitride includes those produced by thinly peeling boron nitride. In the present specification, graphite itself does not fall under the above-mentioned "graphene having a two-dimensional structure".

As described above, graphene or single-layer boron nitride having a two-dimensional structure may be a single layer or a multi-layer. In the case of a plurality of layers, it is usually about 2 to 1,000 layers. The plan-view shape of graphene and single-layer boron nitride having a two-dimensional structure is not particularly limited.

The average particle size of the thermally conductive filler (A) is preferably 0.5 μm or more, more preferably 1.0 μm or more, particularly preferably 3.0 μm or more, and further preferably 5.0 μm. The above is preferable. As a result, the heat conductive fillers (A) are easily brought into contact with each other, and a heat conduction path is easily formed. Therefore, the characteristics of the two-dimensional structure function, and the obtained adhesive film has excellent heat conductivity. Become. The average particle size of the heat conductive filler (A) is preferably 30 μm or less, particularly preferably 20 μm or less, and further preferably 15 μm or less. As a result, the dispersed state is maintained in other materials such as the solvent and the binder polymer (C), the heat conduction path is suppressed from being formed due to segregation, and the adhesive film becomes more excellent in heat conductivity.

Further, the thickness of the thermally conductive filler (A) is preferably 500 nm or less, more preferably 300 nm or less, particularly preferably 200 nm or less, and further preferably 100 nm or less. As a result, the flexibility of the obtained adhesive film is maintained well. On the other hand, the lower limit of the thickness of the heat conductive filler (A) is not particularly limited, but is usually 0.7 nm or more, preferably 5.0 nm or more, and particularly preferably 10 nm or more from the viewpoint of heat conductivity. It is preferably 15 nm or more, and more preferably 15 nm or more.

The content of the heat conductive filler (A) in the adhesive resin composition R is preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 15% by mass or more. It is preferable, more preferably 20% by mass or more. Since the lower limit of the content of the heat conductive filler (A) is as described above, the heat conductive fillers (A) are likely to come into contact with each other and a heat conductive path is easily formed, so that the obtained adhesive film can be obtained. It becomes superior in thermal conductivity.

The content of the thermally conductive filler (A) in the adhesive resin composition R is preferably 60% by mass or less, more preferably 55% by mass or less, and particularly preferably 50% by mass or less. It is preferably 40% by mass or less. When the upper limit of the content of the thermally conductive filler (A) is as described above, the obtained adhesive film is suppressed from becoming mechanically brittle, and the flexibility becomes more excellent. In the present embodiment, by using the heat conductive filler (A) and performing the predetermined heat treatment as described above, the desired heat conductivity can be obtained even with a relatively small content as described above.

(2) Thermosetting component (B)
The thermosetting component (B) in the present embodiment is not particularly limited as long as it enables thermosetting of the adhesive resin composition R and exhibits adhesiveness by thermosetting, and is not particularly limited, for example, an epoxy resin or a phenol resin. , Melamine resin, urea resin, polyester resin, urethane resin, acrylic resin, polyimide resin, benzoxazine resin, phenoxy resin and the like. These can be used alone or in combination of two or more. Among these, an epoxy resin is preferable from the viewpoint of dispersibility and adhesiveness of the thermally conductive filler (A). The "epoxy resin" in the present specification also includes a non-polymerized or low molecular weight epoxy compound for convenience.

Examples of the epoxy resin include glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenylnovolac and cresolnovolac; glycidyl ethers of alcohols such as butanediol, polyethylene glycol and polypropylene glycol; phthalic acid and isophthalic acid. Glycidyl ether of carboxylic acid such as tetrahydrophthalic acid; glycidyl type or alkyl glycidyl type epoxy resin in which active hydrogen bonded to a nitrogen atom such as aniline isocyanurate is replaced with a glycidyl group; vinylcyclohexanediepoxide, 3,4-epoxycyclohexyl Intramolecular carbon-carbon, such as methyl-3,4-dicyclohexanecarboxylate, 2- (3,4-epoxy) cyclohexyl-5,5-spiro (3,4-epoxy) cyclohexane-m-dioxane, etc. For example, a so-called alicyclic epoxide in which an epoxy is introduced by oxidizing a double bond can be mentioned. In addition, an epoxy resin having a biphenyl skeleton, a triphenylmethane skeleton, a dicyclopentadiene skeleton, a dicyclopentadiene skeleton, a naphthalene skeleton, an anthracene skeleton, or the like, or a polyfunctional epoxy resin can also be used. These epoxy resins can be used alone or in combination of two or more.

As the thermosetting component (B) in the present embodiment, it is preferable to use at least an epoxy resin having a π-conjugated mesogen skeleton from the viewpoint of dispersibility of the thermally conductive filler (A). As the epoxy resin having a π-conjugated mesogen skeleton, an epoxy resin having a naphthalene skeleton or an epoxy resin having a biphenyl skeleton is preferable, and an epoxy resin having a naphthalene skeleton is particularly preferable. As the epoxy resin having a naphthalene skeleton, for example, those represented by the following formula (1) are preferably mentioned.

(In the formula, n is an integer greater than or equal to 0.)

The epoxy equivalent of the epoxy resin having the π-conjugated mesogen skeleton is preferably 100 g / eq or more, particularly preferably 150 g / eq or more, and further preferably 180 g / eq or more. The epoxy equivalent is preferably 500 g / eq or less, particularly preferably 400 g / eq or less, and more preferably 300 g / eq or less. As a result, the dispersibility of the thermally conductive filler (A) becomes more excellent, and the adhesive property using the epoxy group is easily exhibited. The epoxy equivalent in the present specification is a value measured according to JIS K7236.

The softening point of the epoxy resin having the π-conjugated mesogen skeleton is preferably 40 ° C. or higher, particularly preferably 50 ° C. or higher, and further preferably 60 ° C. or higher. The softening point is preferably 200 ° C. or lower, particularly preferably 150 ° C. or lower, and further preferably 120 ° C. or lower. As a result, the dispersibility of the thermally conductive filler (A) becomes more excellent. The softening point in the present specification is a value measured according to the measurement method by the ring-and-ball method described in JIS K7234: 1986.

As the thermosetting component (B) in the present embodiment, it is preferable to use a phenolic glycidyl ether from the viewpoint of adjusting the adhesiveness and adhesiveness together with the above-mentioned epoxy resin having a π-conjugated mesogen skeleton. Examples of the phenolic glycidyl ether include those described above, and among them, it is preferable to use a bisphenol F type epoxy resin.

The epoxy equivalent of the glycidyl ether of the above phenols is preferably 100 g / eq or more, particularly preferably 120 g / eq or more, and further preferably 150 g / eq or more. The epoxy equivalent is preferably 500 g / eq or less, particularly preferably 400 g / eq or less, and more preferably 300 g / eq or less. As a result, the adhesiveness and adhesiveness of the obtained adhesive film become more excellent.

The content of the thermosetting component (B) in the adhesive resin composition R is preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 15% by mass or more. It is preferable, more preferably 20% by mass or more. When the lower limit of the content of the thermosetting component (B) is the above, the adhesive resin composition R can be sufficiently cured, and more excellent mechanical strength and adhesiveness can be exhibited. The content is preferably 45% by mass or less, more preferably 40% by mass or less, particularly preferably 35% by mass or less, and further preferably 30% by mass or less. .. When the upper limit of the content of the thermosetting component (B) is as described above, the content of other components can be secured.

When an epoxy resin having a π-conjugated mesogen skeleton and a phenolic glycidyl ether are used in combination, the blending ratio (mass standard) thereof is preferably 20:80 to 95: 5, and 40:60 to 90: The ratio is more preferably 10, particularly preferably 50:50 to 85:15, and further preferably 60:40 to 80:20. This makes it possible to achieve a good balance between the dispersibility of the heat conductive filler (A) and the adhesiveness / adhesiveness of the adhesive film.

(3) Binder polymer (C)
The binder polymer (C) is blended for the purpose of forming the adhesive resin composition R into a film, giving an appropriate tack to the obtained adhesive film, and the like. As such a binder polymer, for example, an acrylic polymer, a polyester resin, a phenoxy resin, a urethane resin, a silicone resin, a rubber polymer and the like are used, and an acrylic polymer is particularly preferably used.

Examples of the acrylic acid polymer include a (meth) acrylic acid ester polymer obtained by polymerizing a (meth) acrylic acid ester monomer and the like. In addition, in this specification, (meth) acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms. In addition, the concept of "polymer" shall be included in "polymer".

Examples of the monomer constituting the (meth) acrylate polymer include carbons of alkyl groups such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. Examples thereof include (meth) acrylic acid alkyl esters having a number of 1 to 18, and functional group-containing monomers having a functional group in the molecule. Examples of the functional group-containing monomer include a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer), a monomer having a carboxy group in the molecule (carboxy group-containing monomer), and a monomer having an amino group in the molecule (amino group-containing monomer). ) And the like. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester polymer used as the binder polymer (C) in the present embodiment is a copolymerization of a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 18 carbon atoms and a functional group-containing monomer. It is preferable that it is an ester. The number of carbon atoms of the alkyl group in the (meth) acrylic acid alkyl ester is preferably 1 to 9, particularly preferably 1 to 6, and further preferably 1 to 3. As the (meth) acrylic acid alkyl ester, methyl (meth) acrylate is particularly preferable, and methyl acrylate is most preferable.

As the functional group-containing monomer, a hydroxyl group-containing monomer is preferable. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and (meth). ) Acrylic acid (meth) Acrylic acid hydroxyalkyl esters such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth) acrylic acid can be mentioned. Among these, 2-hydroxyethyl (meth) acrylate is particularly preferable, and 2-hydroxyethyl acrylate is most preferable.

By using the above-mentioned monomer, the thermally conductive filler (A) can be easily dispersed in the adhesive resin composition R.

When a (meth) acrylic acid ester polymer obtained by copolymerizing the above (meth) acrylic acid alkyl ester and a functional group-containing monomer is used as the binder polymer (C), the (meth) acrylic acid ester polymer is contained. The structural unit derived from the functional group-containing monomer is preferably contained in the range of 5 to 50% by mass, particularly preferably in the range of 8 to 30% by mass, and further preferably in the range of 10 to 20% by mass. It is preferably contained.

The weight average molecular weight of the acrylic polymer ((meth) acrylic acid ester polymer) as the binder polymer (C) is preferably 50,000 or more, more preferably 100,000 or more, and particularly preferably 150,000 or more. It is preferably present, and more preferably 200,000 or more. The weight average molecular weight is preferably 1 million or less, more preferably 700,000 or less, particularly preferably 500,000 or less, and further preferably 400,000 or less. When the weight average molecular weight is in the above range, the film forming property and the adhesiveness become good, and the dispersibility of the heat conductive filler (A) becomes better. The weight average molecular weight in the present specification is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method.

The glass transition temperature (Tg) of the acrylic polymer ((meth) acrylic acid ester polymer) as the binder polymer (C) is preferably −20 ° C. or higher, more preferably −15 ° C. or higher. It is preferable, particularly preferably −10 ° C. or higher, and further preferably −5 ° C. or higher. The glass transition temperature (Tg) is preferably 60 ° C. or lower, more preferably 50 ° C. or lower, particularly preferably 40 ° C. or lower, and further preferably 35 ° C. or lower. .. When the glass transition temperature (Tg) is in the above range, the film forming property and the adhesiveness become good, and the dispersibility of the heat conductive filler (A) becomes better. The glass transition temperature (Tg) of the (meth) acrylic acid ester polymer in the present specification is a value calculated based on the FOX formula.

The content of the binder polymer (C) in the adhesive resin composition R is preferably 1% by mass or more, more preferably 2% by mass or more, and particularly preferably 3% by mass or more. Further, it is preferably 4% by mass or more. The content is preferably 60% by mass or less, more preferably 50% by mass or less, particularly preferably 45% by mass or less, and further preferably 40% by mass or less. .. When the content of the binder polymer (C) is in the above range, the film formability and the adhesiveness are improved while maintaining good mechanical strength and adhesiveness of the cured product of the adhesive film. The dispersibility of the thermally conductive filler (A) becomes better.

(4) Hardener (D)
The adhesive resin composition R in the present embodiment preferably further contains a curing agent (D). Thereby, the adhesive resin composition R can be satisfactorily cured.

The curing agent (D) is not particularly limited as long as it can cure the thermosetting component (B) by heating, but phenols, amines, thiols and the like are preferably mentioned, and the above-mentioned thermosetting is preferable. It can be appropriately selected depending on the type of the sex component (B). For example, when an epoxy resin is used as the thermosetting component (B), phenols are preferable from the viewpoint of reactivity with the epoxy resin and the like. Further, from the viewpoint of dispersibility of the thermally conductive filler (A), it is preferable to use a compound having a π-conjugated mesogen skeleton, and it is particularly preferable to use phenols having a π-conjugated mesogen skeleton.

Examples of the phenols include bisphenol A, tetramethylbisphenol A, diallyl bisphenol A, biphenol, bisphenol F, diallyl bisphenol F, triphenylmethane type phenol, tetrakisphenol, novolak type phenol resin, cresol novolac resin, and biphenyl type phenol resin. And so on. Examples of phenols having a conjugated mesogen skeleton include the above-mentioned biphenyl-type phenols. These can be used alone or in combination of two or more.

Among the above, novolak-type phenol resin or biphenyl-type phenol resin is preferable, and it is particularly preferable to use both novolak-type phenol resin and biphenyl-type phenol resin in combination.

The hydroxyl group equivalent of the novolak type phenol resin is preferably 70 g / eq or more, particularly preferably 80 g / eq or more, and further preferably 90 g / eq or more. The hydroxyl group equivalent is preferably 300 g / eq or less, particularly preferably 280 g / eq or less, and more preferably 250 g / eq or less. As a result, the curability of the epoxy resin becomes more excellent. The hydroxyl group equivalent in the present specification is a value measured according to JIS K0070.

As the biphenyl type phenol resin, for example, those represented by the following formulas (2) and (3) are preferably mentioned.

(In the formula, n is an integer of 1 or more.)

The hydroxyl group equivalent of the biphenyl-type phenol resin is preferably 80 g / eq or more, particularly preferably 85 g / eq or more, and further preferably 90 g / eq or more. The hydroxyl group equivalent is preferably 300 g / eq or less, particularly preferably 280 g / eq or less, and more preferably 250 g / eq or less. This prevents the inclusion of substances that inhibit the curing reaction that remain as unreactants during synthesis, such as elemental phenol, and makes the epoxy resin more excellent in curability.

The softening point of the novolak-type phenol resin and the biphenyl-type phenol resin is preferably 60 ° C. or higher, particularly preferably 80 ° C. or higher, and further preferably 90 ° C. or higher. The softening point is preferably 200 ° C. or lower, particularly preferably 150 ° C. or lower, and further preferably 130 ° C. or lower. When the novolak-type phenol resin or the biphenyl-type phenol resin does not soften, its sublimation temperature is preferably 270 ° C. or higher. The sublimation temperature is preferably 330 ° C. or lower. Those having a high softening point or a high sublimation temperature effectively exhibit the interaction by π electrons, and the dispersibility of the thermally conductive filler (A) becomes more excellent.

The content of the curing agent (D) in the adhesive resin composition R is preferably 2% by mass or more, more preferably 4% by mass or more, and particularly preferably 5% by mass or more. Further, it is preferably 8% by mass or more. The content is preferably 40% by mass or less, more preferably 35% by mass or less, particularly preferably 30% by mass or less, and further preferably 25% by mass or less. .. When the content of the curing agent (D) is in the above range, the curability of the adhesive resin composition R becomes better.

When the novolak type phenol resin and the biphenyl type phenol resin are used in combination, the compounding ratio (mass standard) thereof is preferably 80:20 to 10:90, more preferably 70:30 to 20:80. It is preferable, particularly preferably 65:35 to 25:75, and further preferably 60:40 to 30:70. Thereby, the curability of the adhesive resin composition R and the dispersibility of the heat conductive filler (A) can be well balanced.

(5) Curing accelerator (E)
The adhesive resin composition R in the present embodiment preferably further contains a curing accelerator (E) that promotes or adjusts the reaction between the thermosetting component (B) and the curing agent (D) described above.

Examples of the curing accelerator (E) include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris (dimethylaminomethyl) phenol; 2-methylimidazole, 2-phenylimidazole, and the like. Imidazoles such as 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole; tributylphosphine, diphenylphosphine, triphenylphosphine and the like. Organic phosphins; tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate can be mentioned. These can be used alone or in admixture of two or more.

When an epoxy resin is used as the thermosetting component (B) and phenols are used as the curing agent (D), the reactivity of these compounds, storage stability, physical properties of the cured product, curing speed, etc. Therefore, it is preferable to use an imidazole-based curing accelerator, and in particular, 2-phenyl-4,5-hydroxymethylimidazole is preferably used.

The content of the curing accelerator (E) in the adhesive resin composition R is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, and particularly 0.005% by mass. The above is preferable, and more preferably 0.01% by mass or more. The content is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, particularly preferably 0.1% by mass or less, and further preferably 0.05% by mass. It is preferably mass% or less. When the content of the curing accelerator (E) is in the above range, the storage stability of the adhesive film is improved and the adhesive resin composition R can be cured satisfactorily.

(6) Various Additives Various additives such as a tackifier, a flame retardant, an antioxidant, a light stabilizer, a softener, and a rust preventive are added to the adhesive resin composition in the present embodiment, if desired. can do.

2. 2. Preparation of Adhesive Resin Composition The adhesive resin composition R in the present embodiment contains a heat conductive filler (A) composed of at least one of graphene having a two-dimensional structure and single-layer boron nitride, and a thermosetting component (a thermosetting component (A). It can be obtained by sufficiently mixing B), a binder polymer (C), a curing agent (D), a curing accelerator (E), an additive, and a solvent, if desired. If any of the above components is in the form of a solid, or if precipitation occurs when the components are mixed with other components in an undiluted state, the components may be used alone in advance as a solvent. It may be dissolved or diluted and then mixed with other ingredients.

The adhesive resin composition R in the present embodiment is prepared by mixing the thermally conductive filler (A) and the binder polymer (C) in advance in a solvent, and then further adding a thermosetting component (B), if desired. It is preferable to add a curing agent (D), a curing accelerator (E), an additive and the like. By mixing the heat conductive filler (A) and the binder polymer (C) in advance before blending the thermosetting component (B) and the like, the dispersibility of the heat conductive filler (A) becomes better. , Segregation of the thermally conductive filler (A) in the coating film is suppressed. As a result, the heat conductive filler (A) is uniformly dispersed in the obtained adhesive film, and an adhesive film having better heat conductivity can be obtained.

The heat conductive filler (A) and the binder polymer (C) are preferably mixed in a solvent at a speed of 500 to 5000 rpm of the disper for 10 minutes or more, preferably at the same speed of 1000 to 40,000 rpm. It is more preferable to stir for 20 minutes or more.

The solvent is not particularly limited, and is, for example, an aliphatic hydrocarbon such as hexane, heptane, or cyclohexane, an aromatic hydrocarbon such as toluene or xylene, a halogenated hydrocarbon such as methylene chloride or ethylene chloride, methanol, or the like. Alcohols such as ethanol, propanol, butanol, 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone, esters such as ethyl acetate and butyl acetate, cellosolvent solvents such as ethyl cellosolve, N. , N-Dimethylformamide, trimethyl-2-pyrrolidone, butylcarbitol and the like are used, but methylethylketone is preferable.

The viscosity of the coating liquid of the adhesive resin composition R thus prepared is not particularly limited as long as it can be coated, and can be appropriately selected depending on the situation. It should be noted that the addition of the diluting solvent or the like is not a necessary condition, and the diluting solvent may not be added as long as the adhesive resin composition R has a viscosity and the like that can be coated.

3. 3. Production of Adhesive Film The adhesive film according to the present embodiment is obtained by forming the adhesive resin composition R obtained above into a film. In forming the adhesive resin composition R into a film, it is preferable to use a release sheet as a coating target. For example, the adhesive film according to the present embodiment can be easily produced by applying the coating liquid of the adhesive resin composition R to the release sheet and removing the diluting solvent by heating and drying.

Examples of the release sheet include a resin film, a non-woven fabric, and paper, but a resin film is generally used. Examples of the resin film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, and polybutylene terephthalate film. Polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. Is used. In addition, these crosslinked films are also used. Further, these laminated films may be used.

It is preferable that the peeling surface (the surface in contact with the adhesive resin composition R) of the peeling sheet is subjected to a peeling treatment. Examples of the release agent used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. However, this peeling treatment is not always necessary.

The thickness of the release sheet is not particularly limited, but is usually about 20 to 150 μm.

The arithmetic average roughness (Ra) of the peeled surface of the peeled sheet is preferably 0.1 μm or less, more preferably 0.05 μm or less, and particularly preferably 0.01 μm or less. Since the arithmetic average roughness (Ra) of the peeling surface of the release sheet is as described above, even if the roughness of the release surface of the release sheet is transferred to the adhesive film, the arithmetic average roughness (Ra) of the adhesive film will be described later. It becomes easy to adjust to a preferable range. The method for measuring the arithmetic mean roughness (Ra) in the present specification is as shown in a test example described later.

As an example of manufacturing an adhesive film, the coating liquid of the adhesive resin composition R is applied to the peeling surface of the release sheet. As the coating method, for example, a bar coat method, a knife coat method, a roll coat method, a blade coat method, a die coat method, a gravure coat method and the like can be used.

Next, the coating film of the adhesive resin composition R is dried and a diluting solvent or the like is volatilized to obtain an adhesive film. The drying conditions are preferably 90 to 150 ° C. for 0.5 to 30 minutes, and particularly preferably 100 to 120 ° C. for 1 to 10 minutes. The heating temperature of the drying treatment needs to be lower than the thermosetting temperature of the adhesive resin composition R.

After the above drying treatment, it is preferable to laminate another peelable protective film on the exposed surface of the adhesive film to protect the adhesive film. At this time, the protective film is laminated so that the peelable surface of the removable protective film comes into contact with the exposed surface of the adhesive film. As a result, a laminate made of a release sheet / adhesive film / protective film can be obtained.

As the protective film, the same one as the above-mentioned release sheet mainly composed of the resin film can be used. The protective film may or may not be peeled off as long as it has peelability with respect to the adhesive film.

The adhesive film (laminated body) obtained as described above is preferably heat-pressed. By hot-pressing the adhesive film, the voids existing inside the adhesive film can be reduced, and the thermal conductivity becomes more excellent. Specifically, the heat press makes it easier for the heat conductive fillers (A) to come into contact with each other, makes it easier for the heat conduction path to be formed, and makes the heat conductivity more excellent. By performing such a hot press, the amount of the heat conductive filler (A) blended in the adhesive film can be further reduced, and the flexibility and adhesiveness of the adhesive film can be further improved.

In the adhesive film according to the present embodiment, as described above, a preheating step of holding the adhesive film at a temperature of a specific temperature (T) or less for 30 minutes or more, and a complete curing step of completely curing the adhesive film after the preheating step. It is possible to easily reduce the area ratio of the void portion in the cross section in the thickness direction of the obtained cured product to 10% or less by performing the heat treatment containing the above-mentioned heat press. The area ratio can be made easier by 10% or less.

The heating temperature of the hot press shall be lower than the curing reaction temperature of the thermosetting component (B). Specifically, it is preferably 30 to 90 ° C, more preferably 40 to 80 ° C, particularly preferably 45 to 70 ° C, and further preferably 45 to 60 ° C.

The pressure of the hot press is preferably 0.5 to 15 MPa, more preferably 1 to 10 MPa, particularly preferably 1.5 to 5 MPa, and further preferably 2 to 4 MPa.

The heat pressing time is preferably 0.5 to 60 minutes, more preferably 1 to 50 minutes, particularly preferably 2 to 40 minutes, and further preferably 3 to 30 minutes. ..

By setting the conditions of the hot press as described above, it is possible to easily make each physical property of the cured body obtained by curing the adhesive film within the preferable range described later.

4. Physical properties of the adhesive film (1) Thickness of the adhesive film The thickness of the adhesive film (including the adhesive film that has not been heat-pressed and the adhesive film that has been heat-pressed) according to this embodiment is the thickness (value measured according to JIS K7130). The lower limit is preferably 0.5 μm or more, more preferably 1 μm or more, particularly preferably 5 μm or more, and further preferably 10 μm or more. When the lower limit of the thickness of the adhesive film is the above, it is easy to exhibit good adhesive force and adhesive force.

The thickness of the adhesive film according to the present embodiment is preferably 1000 μm or less, more preferably 500 μm or less, particularly preferably 200 μm or less, and further preferably 100 μm or less as an upper limit value. Is preferable. When the upper limit of the thickness of the adhesive film is the above, the thermal conductivity becomes better. The adhesive film may be formed as a single layer, or may be formed by laminating a plurality of layers.

(2) Arithmetic mean roughness (Ra)
The arithmetic mean roughness (Ra) of at least one surface of the adhesive film (including the non-hot pressed adhesive film and the hot pressed adhesive film) is preferably 0.5 μm or less, preferably 0.4 μm or less. It is more preferably present, particularly preferably 0.35 μm or less, and further preferably 0.3 μm or less. When the upper limit of the arithmetic average roughness (Ra) of the adhesive film is the above, the adhesiveness to the adherend, that is, the temporary adhesiveness becomes more excellent, and the handleability becomes good. Further, since the contact area with the adherend becomes large, the thermal conductivity with the adherend becomes more excellent. If the arithmetic average roughness (Ra) exceeds the upper limit, the thermally conductive filler (A) segregates on the surface of the adhesive film, and the resin component is not present on the surface of the adhesive film at all, or even if it is present. It may be in trace amounts. As a result, the temporary adhesiveness may be insufficient when attached to the adherend.

On the other hand, the arithmetic mean roughness (Ra) of the adhesive film is preferably 0.01 μm or more, more preferably 0.02 μm or more, particularly preferably 0.03 μm or more, and further preferably 0. It is preferably 05 μm or more. When the thermally conductive filler (A) segregates on the surface of the adhesive film, the arithmetic mean roughness (Ra) tends to increase. Since the lower limit of the arithmetic average roughness (Ra) of the adhesive film is as described above, it can be said that the heat conductive filler (A) is present on the surface of the adhesive film, and the heat between the adhesive film and the adherend can be said to be present. The conductivity will be better.

(3) Adhesive strength The adhesive strength of the adhesive film (including the adhesive film that has not been hot-pressed and the adhesive film that has been hot-pressed) to a silicon wafer (arithmetic average roughness (Ra): 0.02 μm or less) is 0.1 mN / It is preferably 25 mm or more, more preferably 0.5 mN / 25 mm or more, particularly preferably 0.8 mN / 25 mm or more, and further preferably 1.0 mN / 25 mm or more. As a result, it adheres well to the adherend and can exhibit excellent temporary adhesiveness.

The upper limit of the adhesive strength is not particularly limited, but is usually preferably 5.0 mN / 25 mm or less, more preferably 3.0 mN / 25 mm or less, and particularly preferably 2.5 mN / 25 mm or less. It is preferably 2.0 mN / 25 mm or less. As a result, the reworkability is excellent. The adhesive strength in the present specification basically refers to the adhesive strength measured by the 180-degree peeling method according to JIS Z0237: 2009, and the specific measuring method is as shown in the test example described later. ..

[Adhesive film with support sheet]
The adhesive film with a support sheet according to an embodiment of the present invention is laminated with the above-mentioned adhesive film (including a heat-pressed adhesive film and a heat-pressed adhesive film) on at least one surface side of the adhesive film. It is equipped with a support sheet. The support sheet may be peeled off from the adhesive film in the future.

By supporting the adhesive film on the support sheet, for example, the processability of the adherend can be improved. As an example, even if it is difficult to process the adherend with the adhesive film alone, the adhesive film with a support sheet is attached to one adherend, processed in that state, and then the support sheet is peeled off. A process such as attaching an adhesive film to another adherend can be performed.

FIG. 1 shows an adhesive film with a support sheet as an example in this embodiment. The adhesive film 2 with a support sheet shown in FIG. 1 includes an adhesive film 1, a support sheet 11 laminated on one surface of the adhesive film 1 (upper surface in FIG. 1), and the other of the adhesive film 1. It is configured to include a release sheet 12 laminated on a surface (lower surface in FIG. 1). The release sheet 12 is laminated on the adhesive film 1 so that its peelable surface is in contact with the adhesive film 1. The release sheet 12 protects the adhesive film 1 until the adhesive film 1 is used, and may be omitted. Further, in the adhesive film with a support sheet in the present embodiment, a protective film may be laminated instead of the release sheet 12.

The support sheet 11 is not particularly limited as long as it can exhibit sufficient mechanical strength to support the adhesive film 1. Examples of the material constituting the support sheet 11 include a resin film, a non-woven fabric, and paper, and a resin film is generally used.

Specific examples of the resin film include a polyethylene film such as a low density polyethylene (LDPE) film, a linear low density polyethylene (LLDPE) film, and a high density polyethylene (HDPE) film, a polypropylene film, an ethylene-propylene copolymer film, and a polybutene. Polyolefin films such as films, polybutadiene films, polymethylpentene films, ethylene-norbornene copolymer films, norbornene resin films; ethylene-vinyl acetate copolymer films, ethylene- (meth) acrylic acid copolymer films, ethylene- Ethylene-based copolymer film such as (meth) acrylic acid ester copolymer film; polyvinyl chloride-based film such as polyvinyl chloride film and vinyl chloride copolymer film; polyester-based film such as polyethylene terephthalate film and polybutylene terephthalate film. ; Polyurethane film; Polyimide film; Polystyrene film; Polycarbonate film; Fluororesin film and the like. Further, modified films such as these crosslinked films and ionomer films are also used. Further, it may be a laminated film in which a plurality of the same type or different types of the above film are laminated. The support sheet 11 may be a release sheet. The support sheet 11 may be, for example, one in which a known pressure-sensitive adhesive layer is provided on the above-mentioned resin film, non-woven fabric, paper, or the like.

The thickness of the support sheet 11 is preferably 20 μm or more, particularly preferably 40 μm or more, and further preferably 60 μm or more. The thickness is preferably 150 μm or less, particularly preferably 120 μm or less, and further preferably 110 μm or less. When the thickness of the support sheet 11 is within the above range, the support sheet 11 tends to have the desired mechanical strength, and the adherend workability and the like are good.

The adhesive film 2 with a support sheet may be a dicing / die bonding sheet used when manufacturing a semiconductor device. In this case, the adhesive film 2 with a support sheet can be used in the steps of dicing and dicing the semiconductor element, and the cured product of the adhesive film is for releasing the heat generated when the semiconductor device is driven to the outside world. Functions as a heat conductive material. In this case, the support sheet 11 is preferably provided with, for example, a known pressure-sensitive adhesive layer on the surface of the resin film described above on the side of the adhesive film 1.

As an example of manufacturing the adhesive film 2 with a support sheet, the release sheet may be peeled off from the above-mentioned laminate made of the release sheet / adhesive film / protective film and the support sheet may be laminated, or the above-mentioned release sheet / adhesion may be performed. The protective film may be peeled off from the laminate made of the film / protective film and the support sheet may be laminated, or the support sheet may be used instead of the protective film in the above-mentioned method for producing an adhesive film.

[Hardened body]
The cured product according to the embodiment of the present invention is one in which the above-mentioned adhesive film is cured by heat treatment, and preferably the above-mentioned adhesive film after hot pressing is cured by heat treatment.

1. 1. Physical properties (1) Area ratio of void portion The area ratio of the void portion in the thickness direction cross section of the cured product in the present embodiment is preferably 10% or less, more preferably 7% or less, and particularly 5%. It is preferably less than or equal to, and more preferably 4% or less. When the area ratio of the void portion is 10% or less, the heat conductive fillers (A) are in more contact with each other, the heat conduction path is formed at a high density, and the heat conductivity becomes more excellent. .. The lower limit of the area ratio is not particularly limited, and the most preferable value is 0%. The method for deriving the area ratio of the void portion is as shown in the test example described later.

(2) Maximum Area of Void portion The maximum area of the void portion in the cross section in the thickness direction of the cured product in the present embodiment is preferably 100 μm ² or less, more preferably 80 μm ² or less, and particularly 60 μm ² or less. It is preferably 50 μm ² or less. When the area ratio of the void portion is 100 μm ² or less, the heat conductive fillers (A) are in more contact with each other, the heat conduction path is formed at a high density, and the heat conductivity becomes more excellent. .. The lower limit of the maximum area is not particularly limited, and most preferably 0 μm ² . The method for deriving the maximum area of the void portion is as shown in a test example described later.

(3) Thermal Conductivity The thermal conductivity of the cured product in the present embodiment is preferably 4 W / mK or more, and particularly preferably 5 W / mK or more. As a result, it can be said that the cured product has excellent thermal conductivity. The cured product according to the present embodiment can achieve such a high thermal conductivity because the adhesive film has the above-mentioned structure. The method for measuring the thermal conductivity in the present specification is as shown in a test example described later.

2. 2. Method for producing a cured product In order to produce a cured product according to the present embodiment, an adhesive film (preferably an adhesive film after hot pressing) is heat-treated and finally completely cured.

In the above heat treatment, the adhesive film is subjected to thermal weight measurement under the condition that the temperature of the adhesive film before any heat treatment is raised from 40 ° C. to 400 ° C. at a temperature rise rate of 10 ° C./min in an air atmosphere. A preheating step of holding the adhesive film at a temperature of 0.5% weight reduction or less (hereinafter sometimes referred to as "preheating temperature") for 30 minutes or more, and a complete curing step of completely curing the adhesive film after the preheating step. It is preferable to include. When the adhesive film is completely cured by a rapid heat treatment, the small molecule components in the adhesive film volatilize and foam due to heating, and voids are likely to be formed inside the adhesive film. On the other hand, when the heat treatment includes the above steps, foaming is suppressed because the small molecule component is taken into the matrix of the thermosetting component (B), the binder polymer (C) and the like and trapped before it volatilizes. This will reduce the voids in the adhesive film. By the above-mentioned preheating step (and the above-mentioned heat press), the area ratio and the maximum area of the above-mentioned void portion become preferable numerical values, and the thermal conductivity of the cured product becomes more excellent.

The preheating temperature is preferably 1 to 50 ° C. lower than the temperature at which the adhesive film loses weight by 0.5%, particularly preferably 10 to 40 ° C., and further preferably 15 to 30 ° C. The lower limit of the preheating temperature is preferably 80 ° C. or higher, particularly 90 ° C. or higher, and more preferably 100 ° C. or higher.

Further, the above preheating step is preferably performed for 30 minutes or more, particularly preferably 30 to 120 minutes, and further preferably 30 to 60 minutes.

It is preferable that the heat treatment is performed by performing the preheating step and then performing a complete curing step at a heating temperature at which the adhesive film is completely cured. The heating temperature in the complete curing step needs to be higher than the above-mentioned preheating temperature, preferably 5 to 100 ° C. higher than the preheating temperature, particularly preferably 10 to 70 ° C., and further. It is preferably 20 to 50 ° C. higher. Specifically, the heating temperature in the complete curing step is preferably 85 to 200 ° C, particularly preferably 100 to 190 ° C, and further preferably 120 to 180 ° C.

Further, the above-mentioned complete curing step is preferably performed for 30 to 180 minutes, particularly preferably 45 to 150 minutes, and further preferably 60 to 120 minutes.

The cured product according to the present embodiment may exist as a single substance, but usually exists in a state of being in contact with one or more members to be thermally conducted.

〔Structure〕
In the structure according to the embodiment of the present invention, at least a part of the first member and at least a part of the second member are bonded via the above-mentioned cured body.

FIG. 2 shows a structure as an example in this embodiment. The structure 3 shown in FIG. 2 includes a first member 31, a second member 32, and a cured body 1A provided between the first member 31 and the second member 32.

The cured product 1A is a product obtained by completely curing the above-mentioned adhesive film (adhesive film 1; including a heat-pressed adhesive film and a heat-pressed adhesive film) by the above-mentioned heat treatment. The first member 31 and the second member 32 are fixed to each other by the adhesiveness of the cured body 1A (adhesive film). The shapes of the first member 31 and the second member 32 in the present embodiment are not particularly limited, but may be a flexible sheet shape, a plate shape, a block shape, or the like. There may be.

The first member 31 (or the second member 32) in the present embodiment is not particularly limited, but for example, a member that generates heat as a result of exerting a predetermined function but is required to suppress a temperature rise, or the member generates heat. A member (heat generating member) that is required to control the flow of heat in a specific direction is preferable. Further, the second member 32 (or the first member 31) is not particularly limited, but a member that dissipates heat received or a member that transfers the received heat to another member (heat transfer member) is preferable. .. Since the cured body 1A in the present embodiment has excellent thermal conductivity, for example, heat for conducting heat of the generated first member 31 to the second member 32 and releasing the heat to the outside world. Functions as a conductive material.

Examples of the heat generating member include thermoelectric conversion devices, photoelectric conversion devices, semiconductor devices such as large-scale integrated circuits, electronic devices such as LED light emitting elements, optical pickups, and power transistors, and various electronic devices such as mobile terminals and wearable terminals. Examples include batteries, batteries, motors, engines, etc. Further, the heat transfer member is preferably made of a highly conductive material, for example, a metal such as aluminum, stainless steel or copper, graphite, carbon nanofibers or the like. The form of the heat transfer member may be any of a substrate, a housing, a heat sink, a heat spreader, and the like, and is not particularly limited.

In order to manufacture the structure 3 according to the present embodiment, one side of the adhesive film described above is attached to the first member 31 (or the second member 32), and then the other side of the adhesive film is attached. It is attached to the second member 32 (or the first member 31). When the adhesive film 2 with a support sheet described above is used, the release sheet 12 is peeled off, one surface of the exposed adhesive film 1 is attached to the first member 31 (or the second member 32), and then the exposed adhesive film 1 is attached. , The support sheet 11 may be peeled off, and the other surface of the exposed adhesive film 1 may be attached to the second member 32 (or the first member 31).

The adhesive film used to manufacture the structure 3 according to the present embodiment may be either a heat-pressed adhesive film or a heat-pressed adhesive film, but a heat-pressed adhesive film is used. Is preferable. Further, after the adhesive film is attached to the first member 31 (or the second member 32) using an adhesive film that has not been heat-pressed, or through the adhesive film, the first member 31 and the first member 31 The adhesive film may be hot-pressed after being bonded to the member 32 of 2. However, if an adhesive film that has been heat-pressed in advance is used, it is possible to prevent the first member 31 and / or the second member 32 from being damaged by the heat press.

Here, any method is used when the first member 31 and the second member 32 are attached to each other via the adhesive film, or when the adhesive film is attached to the first member 31 or the second member 32. When the temperature is higher than the temperature showing the peak of loss tangent (tan δ) obtained by measuring the viscoelasticity of the adhesive film before heat treatment (hereinafter sometimes referred to as “tan δ peak temperature”) (hereinafter referred to as “pasting treatment temperature”). There is.), It is preferable to perform the above-mentioned bonding or pasting. By affixing or affixing at such a temperature, the adhesive film becomes flexible, and it is possible to more effectively suppress the entrainment of air between the adhesive film and the adherend. The thermal conductivity between can be made better. The method for measuring the viscoelasticity of the adhesive film is as shown in a test example described later.

The first member 31 is a flexible sheet-like member, and when the laminated body of the sheet-like member and the adhesive film is attached to the second member 32, or when the adhesive film 2 with a support sheet is attached to the first member. When it is attached to the member 31 or the second member 32, the above-mentioned air entrainment suppressing effect becomes more excellent. Since the laminated body of the sheet-like member and the adhesive film and the adhesive film 2 with a support sheet are flexible and easy to bend, they can be gradually brought into close contact with the adherend from one direction to the other, and air is pushed out. This is because it can be pasted while.

The above-mentioned pasting treatment temperature is preferably 0 to 50 ° C. higher than the tan δ peak temperature, particularly preferably 2 to 30 ° C., and further preferably 5 to 20 ° C. Further, the upper limit of the above-mentioned application processing temperature needs to be lower than the curing temperature of the adhesive film, specifically, it is preferably 120 ° C. or lower, particularly preferably 100 ° C. or lower, and further. It is preferably 90 ° C. or lower.

As described above, one side of the adhesive film is attached to the first member 31 (or the second member 32), and the other side of the adhesive film is attached to the second member 32 (or the first member 31). After being attached to, the heat treatment for producing the cured body of the adhesive film described above is performed to completely cure the adhesive film to obtain a cured body 1A, and the structure 3 according to the present embodiment is obtained.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, in FIG. 1, the release sheet 12 laminated on the adhesive film 1 may be omitted. Further, the shapes of the first member and the first member in the structure are not limited to those shown in FIG. 2, and may be various shapes.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]
The following components (a) and (c) are mixed and diluted with methyl ethyl ketone so that the solid content concentration becomes 15% by mass, and the mixture is stirred with a disper at a rotation speed of 3000 rpm for 30 minutes or more to dissolve and disperse. rice field. The following components (b-1), (b-2), (d-1), (d-2) and (e) are added thereto, and the total solid content concentration is 21% by mass. Methyl ethyl ketone was added so as to be. This mixed solution was stirred with a rotating / revolving mixer (manufactured by Shinky Co., Ltd., product name "AR-100") for 10 minutes to obtain a coating liquid for an adhesive resin composition.

The content (in terms of solid content) of each component in this adhesive resin composition is 30.01% by mass for the component (a), 34.95% by mass for the component (c), and 16 for the component (b-1). .56% by mass, (b-2) component is 7.23% by mass, (d-1) component is 5.61% by mass, (d-2) component is 5.61% by mass, and (e) component is 0. It was 0.03% by mass.

(A) Thermally conductive filler: graphene (manufactured by ADEKA, product name "CNS-1A1", average particle size 12 μm, thickness 50 nm or less, Raman peak intensity ratio D / G = 0.1, CuKα ray by X-ray diffraction method Peak detection at positions where 2θ is 26.6 ° and 42.4 ° when measured using a source (wavelength 0.15418 nm))

(B-1) Thermosetting component: Solid epoxy resin having a naphthalene skeleton represented by the following formula (1) (manufactured by Nippon Kayaku Co., Ltd., product name "NC-7000L", epoxy equivalent 223 to 238 g / eq, ICI viscosity (150 ° C.) 0.50 to 1.00 Pa · s, softening point 83 to 93 ° C.) dissolved in methyl ethyl ketone (solid content concentration 70% by mass)

(In the formula, n is an integer greater than or equal to 0.)

(B-2) Thermosetting component: Bisphenol F type liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "YL983U", epoxy equivalent 165 to 175 g / eq, viscosity (25 ° C.) 3.0 to 6.0 Pa · s )

(C) Binder polymer: Acrylic acid ester polymer (manufactured by Mitsubishi Chemical Co., Ltd., product name "Corponil N-4617", obtained by copolymerizing 85 parts by mass of methyl acrylate and 15 parts by mass of 2-hydroxyethyl acrylate. Copolymer, weight average molecular weight: 300,000, glass transition temperature: 6 ° C) dissolved in a 1: 1 mixed solvent of ethyl acetate and toluene (solid content concentration 36% by mass)

(D-1) Curing agent: Novolac type phenol resin (manufactured by Asahi Organic Materials Industry Co., Ltd., product name "PAPS-PN4", hydroxyl group equivalent 104 g / eq, ICI viscosity (150 ° C.) 3.0 Pa · s, softening point 111 ° C. ) Dissolved in methyl ethyl ketone (solid content concentration 60% by mass)

(D-2) Hardener: A biphenyl-type phenol compound represented by the following formula (3) (manufactured by Honshu Chemical Industry Co., Ltd., product name "BP", hydroxyl group equivalent 93.1 g / eq, sublimation temperature 283 ° C.) with methyl ethyl ketone. Dissolved (solid content concentration 10% by mass)

(E) Curing accelerator: 2-phenyl-4,5-hydroxymethylimidazole

A release sheet (manufactured by Lintec Corporation, product name "SP-PET3811 (S)", peeled off by peeling off one side of a polyethylene terephthalate film with a silicone-based release agent from the coating liquid of the adhesive resin composition obtained in the above step. After applying with an applicator to the peeled surface having an arithmetic mean roughness (Ra): 0.002 μm) on the treated surface, it was heat-treated at 100 ° C. for 2 minutes and dried to form an adhesive film (thickness: 50 μm). .. After that, an adhesive film with a release sheet was attached to the release-treated surface of the protective film (manufactured by Lintec Corporation, product name "SP-PET3811 (S)") in which one side of the polyethylene terephthalate film was peeled off with a silicone-based release agent. A laminate composed of a release sheet, an adhesive film (thickness: 50 μm), and a protective film was obtained.

The laminated body obtained above is cut into 4 cm × 4 cm, and a pressure of 3.0 MPa is applied to the laminated body at 50 ° C. for 30 minutes using a screw type heating press device to heat the adhesive film. Pressed.

[Example 2]
In the hot press, an adhesive film (after hot pressing) was manufactured in the same manner as in Example 1 except that the pressure applied by the screw type hot press device was 2.5 MPa.

[Example 3]
In Test Example 4, which will be described later, the temperature at which the adhesive film after the hot pressing of Example 1 was attached to the silicon wafer was set to 75 ° C. was designated as Example 3.

[Comparative Example 1]
In Test Example 6 to be described later, the adhesive film after the hot pressing of Example 1 was directly heat-treated at 175 ° C. for 3 hours (complete curing step) without performing the preheating step, and was referred to as Comparative Example 1.

[Comparative Example 2]
In the hot press, an adhesive film (also referred to as “adhesive film after hot press” for convenience) was produced in the same manner as in Example 1 except that the pressure applied by the screw type heat press device was 0 MPa.

[Comparative Example 3]
(A) As the thermally conductive filler, instead of graphene in Example 1, spherical alumina particles (manufactured by Showa Denko KK, product name "CB-P05J", average particle diameter 5.0 μm, aspect ratio: 1.1, specific gravity). : 3.98 g / cm ³ ) was used, and an adhesive film was produced in the same manner as in Example 1.

[Comparative Example 4]
(A) Spherical alumina particles as a thermally conductive filler in Comparative Example 3 (manufactured by Showa Denko KK, product name "CB-P05J", average particle diameter 5.0 μm, aspect ratio: 1.1, specific gravity: 3.98 g An adhesive film was produced in the same manner as in Comparative Example 3 except that the blending amount of / ^cm3 ) was changed to 81.4% by mass.

[Comparative Example 5]
In Test Example 6 to be described later, the adhesive film after the hot pressing of Comparative Example 3 was directly heat-treated at 175 ° C. for 3 hours (complete curing step) without performing the preheating step, and was designated as Comparative Example 5.

[Comparative Example 6]
In Test Example 4, which will be described later, the temperature at which the adhesive film after hot pressing of Comparative Example 3 was attached to the silicon wafer was set to room temperature (RT) was designated as Comparative Example 6.

[Test Example 1] <Thermogravimetric analysis (TG measurement)>
The adhesive film before hot pressing obtained in each example and comparative example was measured using a thermal analysis measuring device (manufactured by Shimadzu Corporation, thermal analyzer TG / DTA simultaneous measuring device, product name "DTG-60"). Using an alumina particle in almost the same amount as the sample as a reference sample, thermal weight measurement was performed from 40 ° C. to 400 ° C. at a heating rate of 10 ° C./min under an atmospheric atmosphere, and a temperature at which the weight loss was 0.5% was determined. As a result, the temperature of the adhesive film before hot pressing obtained in Examples 1 to 3 and Comparative Examples 1 to 3, 5 to 6 was 147 ° C., and the temperature was 147 ° C. before the hot pressing obtained in Comparative Example 4. The temperature of the adhesive film was 151 ° C.

[Test Example 2] <Dynamic Viscoelasticity Measurement>
The adhesive films before hot pressing obtained in each Example and Comparative Example were laminated to a thickness of 0.2 mm, and this was cut into a size of 20 mm × 10 mm and used as a measurement sample. The obtained sample was attached to a dynamic viscoelasticity measuring device (manufactured by TA Instruments, product name "DMA-Q800") with a measurement length (distance between chucks) of 10 mm, a frequency of 11 Hz, an amplitude of 5 μm, and ascending. Under the condition of a temperature rate of 3 ° C./min, the loss tangent (tan δ) in the temperature range of 25 to 100 ° C. was measured, and the temperature at which the loss tangent (tan δ) was maximized in the measurement temperature range was determined. As a result, the temperature of the adhesive film before hot pressing obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was 73 ° C., and the temperature was 73 ° C. before the hot pressing obtained in Comparative Examples 3 and 5 to 6. The temperature of the adhesive film was 71 ° C., and the temperature of the adhesive film before hot pressing obtained in Comparative Example 4 was 75 ° C.

[Test Example 3] <Arithmetic Mean Roughness (Ra) Measurement>
(1) Peeling-treated surface of the peeling sheet Regarding the surface roughness of the peeling-treated surface of the peeling sheet used in each example and comparative example, the scanning probe microscope (SPM) device (manufactured by Hitachi High-Tech Science Co., Ltd., product name "SPA-" Using 300 HV "), the sample surface was measured in the range of 5 μm × 5 μm in the DFM mode, and the arithmetic mean roughness (Ra) was measured. As the cantilever, "OMCL-AC240TS-C3" (resonance frequency; 55-65 kHz, spring constant; about 2 N / m ² ) manufactured by Olympus was used. As a result, the arithmetic average roughness (Ra) of the peeled surface of the peeled sheet was 0.002 μm.

(2) Surface of adhesive film Shape measurement laser microscope for surface roughness of the surface of the adhesive film after hot pressing (the surface that was in contact with the peeled surface of the release sheet) obtained in each example and comparative example. Using (Keence Co., Ltd., product name "3D Laser Microscope VK-9700"), measure in the range of 700 x 500 μm ² with a cutoff of 2.5 mm in accordance with JIS B0601: 2001, and the arithmetic average roughness. The roughness (Ra) was measured. The results are shown in Table 1.

[Test Example 4] <Adhesive strength measurement>
The coating liquid of the adhesive resin composition obtained in each Example and Comparative Example was applied to one side of a polyethylene terephthalate film having a thickness of 12 μm, heat-treated at 100 ° C. for 2 minutes, dried, and the polyethylene terephthalate film was dried. An adhesive film (thickness: 50 μm) was firmly bonded to the laminate to prepare a laminated body.

Next, for the purpose of protecting the surface of the adhesive film, a release-treated surface of a release film (manufactured by Lintec Corporation, product name "SP-PET38131", thickness 38 μm) was attached to the surface of the laminate on the adhesive film side. The obtained laminate was cut into 4 cm × 4 cm together with the release film, and heat-pressed under the conditions of each example. Then, this was cut together with the release film to obtain a sample for measuring adhesive strength having a width of 25 mm and a length of 40 mm.

Separately, a silicon wafer (manufactured by Science and Technology Research Institute, diameter: 150 mm, thickness: 500 μm) whose surface was chemically and mechanically polished until the arithmetic mean roughness (Ra) became 0.02 μm or less was prepared as an adherend. .. The release film of the adhesive force measurement sample was peeled off, and the exposed surface of the adhesive film was attached to the treated surface of the silicon wafer to obtain a laminate composed of the silicon wafer and the adhesive force measurement sample. The temperature at the time of this application was 80 ° C. (Examples 1 to 2 and Comparative Examples 1 to 5), 75 ° C. (Example 3) or room temperature (Comparative Example 6).

After leaving the obtained laminate in an atmosphere of 23 ° C. and 50% relative humidity for 20 minutes, JIS Z0237: 2000 was used using a universal tensile tester (manufactured by Instron, product name "5581 type tester"). In accordance with the above, a 180 ° peeling test was conducted at a peeling speed of 300 mm / min. The load at the time of this 180 ° peeling was measured, and the measured value was taken as the adhesive force (N / 25 mm). The results are shown in Table 1.

[Test Example 5] <Evaluation of temporary adhesiveness>
The laminate obtained in Test Example 4 was observed, and the temporary adhesiveness was evaluated based on the following criteria. The results are shown in Table 1.
◯: The sample for measuring the adhesive strength adhered to the adherend, and there was no air entrainment at the interface.
Δ: A sample for measuring adhesive strength adhered to the adherend, and air entrainment was confirmed at the interface.
X: The sample for measuring the adhesive strength did not adhere to the adherend.

[Test Example 6] <Evaluation of void portion in cross section of cured product>
1. 1. Area ratio of void portion The laminates after hot pressing obtained in Examples 1 to 3 and Comparative Examples 2 to 4 and 6 were heat-treated at 125 ° C. for 1 hour (preheating step), and then at 175 ° C. for 2 hours. It was heat-treated (completely cured step), and the adhesive film after hot pressing was completely cured to obtain a cured product. On the other hand, in Comparative Examples 1 and 5, the adhesive film after hot pressing was completely cured by directly heat-treating at 175 ° C. for 3 hours without performing the preheating step (complete curing step) to obtain a cured product.

A film having a thickness of about 30 nm is applied to the cross section of the cured body of the above adhesive film using a sputtering device (manufactured by Vacuum Device Co., Ltd., product name "MSP-20-UM magnetron sputtering"), targeting Pt-Pd. Was coated and antistatic treated. Six images of the cross section of the cured product were taken using a scanning electron microscope (SEM) device (manufactured by KEYENCE, product name "VE-9800"). The imaging conditions were an acceleration voltage of 8 kV and a magnification of 1000 times. One SEM image (a cured product of the adhesive film of Example 1) is shown in FIG.

The obtained 6 SEM images were binarized into the void portion and the other portion. Image analysis software (ImageJ) was used for binarization, and the brightness threshold was set to 77-110. FIG. 4 shows a binarized SEM image of a cross section of the cured body of the adhesive film of Example 1 shown in FIG. In the figure, the black part is the void part. For the area ratio of the void portion, the binarized image is used, the total area of the void portion is divided by the area of the entire cross section of the adhesive film obtained from the SEM image, and further, from the average value of the six SEM images. I asked. The results are shown in Table 1.

Since the brightness threshold value differs depending on the condition setting at the time of SEM image observation, the value was determined by comparing with the actual SEM observation image. Further, the binarized image was compared with the original SEM image, and the portion not corresponding to the void portion was appropriately excluded.

For reference, FIG. 5 shows an SEM image of a cross section of the cured body of the adhesive film of Comparative Example 2. Further, similarly to the above, FIG. 6 shows a binarized SEM image shown in FIG.

2. 2. Maximum Area of Void Region Using the binarized images of the above 6 SEM images, the one with the largest area of continuous void portion was determined as the maximum area of the void portion (μm ² ). The results are shown in Table 1.

[Test Example 7] <Measurement and evaluation of thermal diffusivity>
The cured body of the adhesive film obtained in Test Example 6 was cut to obtain a square sample having a side of 5 mm. The thermal diffusivity of the cured product of the adhesive film was measured using a thermal conductivity measuring device (manufactured by aiphase, product name "Eye Phase Mobile 1u"). Then, the thermal diffusivity was multiplied by the specific gravity and the specific heat to calculate the thermal conductivity (W / mK) of the cured product of the adhesive film. The results are shown in Table 1.

As can be seen from Table 1, the cured products of the adhesive films produced in Examples 1 to 3 had excellent thermal conductivity. Further, the adhesive films of Examples 1 to 3 were also excellent in temporary adhesiveness.

The adhesive film and the cured product according to the present invention can be suitably used for cooling the electronic device by interposing it between the heat-generating electronic device and the heat-dissipating substrate or heat sink, for example. Further, the structure according to the present invention is useful as, for example, a structure including an electronic device that generates heat and a heat-dissipating substrate or heat sink.

1 ... Adhesive film 11 ... Support sheet 12 ... Release sheet 2 ... Adhesive film with support sheet 3 ... Structure 1A ... Cured body of adhesive film 31 ... First member 32 ... Second member

Claims

A thermally conductive filler (A) composed of at least one of graphene and single-layer boron nitride having a two-dimensional structure,
Thermosetting component (B) and
An adhesive film made of an adhesive resin composition containing a binder polymer (C).
It is used to perform a heat treatment including a preheating step and a complete curing step of completely curing the adhesive film after the preheating step.
The preheating step is a step of holding the temperature at the following temperature (T) or lower for 30 minutes or more.
An adhesive film characterized by that.
Temperature (T): The adhesive film before any heat treatment was subjected to thermal weight measurement under the condition of raising the temperature from 40 ° C. to 400 ° C. at a heating rate of 10 ° C./min under an atmospheric atmosphere, and the adhesive film was measured. The temperature at which the weight is reduced by 0.5%.
A thermally conductive filler (A) composed of at least one of graphene and single-layer boron nitride having a two-dimensional structure,
Thermosetting component (B) and
An adhesive film made of an adhesive resin composition containing a binder polymer (C).
An adhesive film characterized in that the area ratio of the void portion in the cross section in the thickness direction of the cured product obtained by heat-treating the adhesive film under the following conditions is 10% or less.
(conditions)
The heat treatment includes a preheating step and a complete curing step of completely curing the adhesive film after the preheating step.
In the preheating step, the thermal weight measurement of the adhesive film before any heat treatment is performed under the condition that the temperature of the adhesive film is raised from 40 ° C. to 400 ° C. at a temperature rising rate of 10 ° C./min in an air atmosphere. This is a step of holding the adhesive film at a temperature equal to or lower than a temperature at which the weight is reduced by 0.5% for 30 minutes or more.
The adhesive film according to claim 1 or 2, wherein the content of the heat conductive filler (A) is 5% by mass or more and 60% by mass or less.
The adhesive film according to any one of claims 1 to 3, wherein the thermosetting component (B) is an epoxy resin.
The adhesive film according to any one of claims 1 to 4, which is hot-pressed.
The adhesive film according to any one of claims 1 to 5, wherein the arithmetic average roughness (Ra) of at least one surface is 0.01 μm or more and 0.5 μm or less.
A thermosetting filler (A) composed of at least one of graphene and single-layer boron nitride having a two-dimensional structure and a binder polymer (C) are mixed in a solvent, and then a thermosetting component (B) is further mixed. To obtain an adhesive resin composition by mixing
A method for producing an adhesive film, which comprises forming the obtained adhesive resin composition into a film.
The method for producing an adhesive film according to claim 7, wherein the adhesive resin composition is formed into a film and then heat-pressed.
The method for producing an adhesive film according to claim 8, wherein the heating temperature of the heat press is lower than the curing reaction temperature of the thermosetting component (B).
The adhesive film according to claim 8 or 9, wherein the arithmetic mean roughness (Ra) of at least one surface of the adhesive film after hot pressing is 0.01 μm or more and 0.5 μm or less. Production method.
The adhesive film according to any one of claims 1 to 6 and
An adhesive film with a support sheet provided with a support sheet laminated on at least one surface side of the adhesive film.
A thermally conductive filler (A) composed of at least one of graphene and single-layer boron nitride having a two-dimensional structure,
Thermosetting component (B) and
A cured product obtained by heat-treating an adhesive film made of an adhesive resin composition containing a binder polymer (C).
A cured product characterized in that the area ratio of the void portion in the cross section in the thickness direction is 10% or less.
The cured product according to claim 12, wherein the maximum area of the void portion in the cross section in the thickness direction is 100 μm 2 or less.
The heat treatment includes a preheating step and a complete curing step of completely curing the adhesive film after the preheating step.
When the preheating step performs thermogravimetric measurement under the condition that the temperature of the adhesive film before any heat treatment is raised from 40 ° C. to 400 ° C. at a temperature rising rate of 10 ° C./min in an air atmosphere. The cured product according to claim 12 or 13, comprising a step of holding the adhesive film at a temperature equal to or lower than a temperature at which the weight is reduced by 0.5% for 30 minutes or more.
A thermally conductive filler (A) composed of at least one of graphene and single-layer boron nitride having a two-dimensional structure,
Thermosetting component (B) and
A method for producing a cured product, which comprises heat-treating an adhesive film made of an adhesive resin composition containing a binder polymer (C) to obtain a cured product.
The heat treatment includes a preheating step and a complete curing step of completely curing the adhesive film after the preheating step.
When the preheating step performs thermal weight measurement under the condition that the temperature of the adhesive film before any heat treatment is raised from 40 ° C. to 400 ° C. at a heating rate of 10 ° C./min in an air atmosphere. A method for producing a cured product, which comprises a step of holding the adhesive film at a temperature equal to or lower than a temperature at which the weight is reduced by 0.5% for 30 minutes or more.
The method for producing a cured product according to claim 15, wherein the adhesive film is hot-pressed before the heat treatment.
The method for producing a cured product according to claim 15, wherein the area ratio of the void portion in the cross section in the thickness direction of the cured product is 10% or less.
A thermally conductive filler (A) composed of at least one of graphene and single-layer boron nitride having a two-dimensional structure,
Thermosetting component (B) and
A bonding step of bonding at least a part of the first member to at least a part of the second member via an adhesive film made of an adhesive resin composition containing a binder polymer (C).
After the bonding, the adhesive film is heat-treated to form a cured body, whereby at least a part of the first member and at least a part of the second member are bonded via the cured body. It is equipped with a process to obtain a structure made of
The heat treatment includes a preheating step and a complete curing step of completely curing the adhesive film after the preheating step.
When the preheating step performs thermal weight measurement under the condition that the temperature of the adhesive film before any heat treatment is raised from 40 ° C. to 400 ° C. at a heating rate of 10 ° C./min in an air atmosphere. A method for producing a structure, which comprises a step of holding the adhesive film at a temperature equal to or lower than a temperature at which the weight is reduced by 0.5% for 30 minutes or more.
The method for manufacturing a structure according to claim 15, wherein the adhesive film is hot-pressed before the heat treatment.
The method for manufacturing a structure according to claim 18 or 19, wherein the area ratio of the void portion in the cross section in the thickness direction of the cured product is 10% or less.
The present invention is characterized in that, in the bonding step, the bonding is performed at a temperature equal to or higher than a temperature indicating a peak of loss tangent (tan δ) obtained by measuring the viscoelasticity of the adhesive film before any heat treatment. Item 8. The method for producing a structure according to any one of Items 18 to 20.