JP7786951B2 - Epoxy resin composition, cured product, structure, and electronic component - Google Patents

Description

The present invention relates to an epoxy resin composition, a cured product, a structure, and an electronic component.

Epoxy resin compositions have been used as adhesives and insulating materials for semiconductor elements and printed wiring boards.
In recent years, semiconductor elements and printed wiring boards have become increasingly high-performance, miniaturized, and thin, and there is a demand for multi-layered semiconductor chips and wiring layers, finer and denser wiring, and lower dielectric loss tangents. Furthermore, as electronic materials become smaller and thinner, the importance of film-shaped epoxy resin compositions is increasing for the purpose of thinning adhesive layers and insulating layers.

Regarding epoxy resin compositions in the form of a film, for example, Patent Document 1 discloses a dry film using an epoxy resin composition that has excellent thin film formability, storage stability, and curability.
Furthermore, Patent Document 2 discloses an epoxy resin composition for adhesive films that has good storage stability when formed into a film using a solvent, has excellent curing properties, and is also excellent in long-term reliability.
Furthermore, Patent Document 3 discloses a film-shaped epoxy resin composition using a curing agent that is excellent in low-temperature curing property, solvent resistance, and storage stability, and an epoxy resin composition that uses a microcapsule-type curing agent.

Japanese Patent Application Laid-Open No. 2020-152780 Patent No. 661928 Patent No. 603995

Previously proposed film-shaped epoxy resin compositions have been used for bonding to metal layers, as interlayer insulating materials, and to protect metal wiring. However, these conventional film-shaped epoxy resin compositions have the problem that their adhesive strength to metal deteriorates when stored at room temperature for long periods of time.

The epoxy resin compositions described in Patent Documents 1 to 3 mentioned above tend to have improved stability in the varnish state before being made into a film, but there is still room for improvement in terms of storage stability after being made into a film and preventing a decrease in metal adhesive strength during film storage.

In view of the above-mentioned problems with the conventional technology, the present invention aims to provide an epoxy resin composition that exhibits high adhesive strength to metals and a small rate of decrease in adhesive strength to metals when stored in film form for long periods of time compared to before storage, as well as a structure in which metals and a cured product of the epoxy resin composition are bonded with high adhesive strength.

The present inventors have conducted extensive research to solve the problems of the prior art described above, and as a result have found that the decrease in adhesive strength after long-term storage is due to the fact that epoxy groups react during storage to form high molecular weight compounds and crosslinked structures, which reduces the fluidity of the epoxy resin composition when applied or when thermally cured, resulting in (i) a decrease in adhesive area due to a deterioration in conformity to the substrate, and (ii) a decrease in the mobility of compounds having functional groups with metal-coordinating properties, such as amino groups, to the metal interface.The present inventors have also found that the problems of the prior art described above can be solved by specifying the consumption rate of epoxy groups during storage under specified conditions, and have thus completed the present invention.
That is, the present invention is as follows.

[1]
Component (A): an epoxy resin;
Component (B): a polymer different from the component (A),
Component (C): a heat curing agent;
A film having a support and an epoxy resin composition layer made of an epoxy resin composition, comprising:
When stored for 7 days under a temperature condition of 40 °C, the consumption rate Y (%) of epoxy groups during the storage period is 0% or more and 30% or less,
The component (A) epoxy resin has an epoxy equivalent X (g/eq.) of the entire component (A) epoxy resin, represented by the following formula (1), of 140 or more and 500 or less,
The consumption rate Y (%) of the epoxy group;
The epoxy equivalent X (g/eq.) of the entire epoxy resin of component (A), represented by the following formula (1), is
Satisfies the following formula (2):
A film having an epoxy resin composition layer and a support.
Epoxy equivalent weight X of all epoxy resins in component (A) = total mass of epoxy resins ÷ Σ (mass of each epoxy resin / each epoxy equivalent) ... Equation (1)
Y (%) ≦−0.06×X (g/eq.)+39 Formula (2)
[2]
Component (A): an epoxy resin;
Component (B): a polymer different from the component (A),
Component (C): a heat curing agent;
A film having a support and an epoxy resin composition layer made of an epoxy resin composition, comprising :
when stored for 7 days under a temperature condition of 40°C, the consumption rate Y (%) of epoxy groups during the storage period is 0% or more and 30% or less,
the component (C): heat curing agent contains (C-1): microcapsule-type curing agent,
Component (D): Further containing a monofunctional epoxy compound having an aromatic ring,
A film having an epoxy resin composition layer and a support.
[3]
Component (A): an epoxy resin;
Component (B): a polymer different from the component (A),
Component (C): a heat curing agent;
A film having a support and an epoxy resin composition layer made of an epoxy resin composition, comprising :
when stored for 7 days under a temperature condition of 40°C, the consumption rate Y (%) of epoxy groups during the storage period is 0% or more and 30% or less,
The component (C): a heat curing agent,
(C-2): an active ester curing agent; and (C-3): dicyandiamide.
A film having an epoxy resin composition layer and a support.
[4]
The component (A) epoxy resin has an epoxy equivalent (g/eq.) of 140 or more and 500 or less, as a whole, of the component (A) epoxy resin, as represented by the following formula (1):
A film having the epoxy resin composition layer according to [2] or [3] above and a support.
Epoxy equivalent of all epoxy resins in component (A) = total mass of epoxy resins ÷ Σ (mass of each epoxy resin / each epoxy equivalent) ... Equation (1)
[5]
a protective layer on the surface of the epoxy resin composition layer opposite to the support;
A film having an epoxy resin composition layer according to any one of [1] to [4] above and a support.
[6]
A film having the epoxy resin composition layer according to any one of [1] to [5] above and a support, which is any one selected from the group consisting of an interlayer insulating film, a film-type solder resist, a die attach film , a sealing sheet, an adhesive sheet, a conductive film, an anisotropic conductive film, and a thermally conductive film.
[7]
A cured product of the epoxy resin composition layer constituting a film having the epoxy resin composition layer according to any one of [1] to [6] above and a support.
[8]
A metal substrate;
The cured product according to [7] above,
A structure having:
[9]
An electronic component comprising one or more components selected from the group consisting of a semiconductor element, a flexible substrate, a printed wiring board, a power semiconductor, and a solar panel, and including the cured product according to [7] above.

According to the present invention, an epoxy resin composition can be provided which exhibits a small rate of decrease in adhesive strength to metal even after long-term storage in the form of a film, compared to before storage, and which exhibits high adhesive strength to metal.
Furthermore, the present invention can provide a structure in which the metal and the cured product of the epoxy resin composition are bonded with high strength even after long-term storage.

The graph shows plots of Examples 1 to 11, with the horizontal axis representing the epoxy equivalent (g/eq.) of the entire epoxy resin of component (A): X, and the vertical axis representing the consumption rate PD.R. (%) of the epoxy groups during storage at 40°C for 7 days: Y.

Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail.
The following embodiments are merely examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be implemented by modifying it as appropriate within the scope of its gist.

[Epoxy resin composition]
The epoxy resin composition of the present embodiment comprises:
Component (A): an epoxy resin;
Component (B): a polymer different from the component (A),
Component (C): a heat curing agent;
Including,
When the composition is stored in the form of a film at a temperature of 40°C for 7 days, the consumption rate (%) of epoxy groups during the storage period is 0% or more and 30% or less.
By having the above-mentioned constitution, an epoxy resin composition can be obtained which exhibits a small rate of decrease in adhesive strength to metal even after long-term storage compared to before storage, and which exhibits high adhesive strength to metal.

(Component (A): Epoxy resin)
The epoxy resin composition of the present embodiment contains component (A) epoxy resin (hereinafter, may be referred to as (A) epoxy resin or component (A)).
Note that component (D), a monofunctional epoxy compound having an aromatic ring, which will be described later, is not included in component (A), an epoxy resin, and these can be distinguished by the number of epoxy groups in one molecule. In this embodiment, the epoxy resin (A) refers to a compound having two or more epoxy groups in one molecule, and a polymer compound.

(A) Epoxy resins include, but are not limited to, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD type epoxy resins, bisphenol M type epoxy resins, bisphenol P type epoxy resins, tetrabromobisphenol A type epoxy resins, biphenyl type epoxy resins, tetramethylbiphenyl type epoxy resins, tetrabromobiphenyl type epoxy resins, diphenyl ether type epoxy resins, benzophenone type epoxy resins, phenyl benzoate type epoxy resins, diphenyl sulfide type epoxy resins, diphenyl sulfoxide type epoxy resins, diphenyl sulfone type epoxy resins, diphenyl disulfide type epoxy resins, naphthalene type epoxy resins, anthracene type epoxy resins, hydroquinone type epoxy resins, methyl hydrochloride type epoxy resins, methyl hydroxybenzoates ... Examples of epoxy resins include bifunctional epoxy resins such as quinone-type epoxy resins, dibutylhydroquinone-type epoxy resins, resorcinol-type epoxy resins, methylresorcinol-type epoxy resins, and catechol-type epoxy resins; trifunctional epoxy resins such as N,N-diglycidylaminobenzene-type epoxy resins and triazine-type epoxy resins; tetrafunctional epoxy resins such as tetraglycidyldiaminodiphenylmethane-type epoxy resins and diaminobenzene-type epoxy resins; polyfunctional epoxy resins such as phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, triphenylmethane-type epoxy resins, tetraphenylethane-type epoxy resins, dicyclopentadiene-type epoxy resins, naphthol aralkyl-type epoxy resins, and brominated phenol novolac-type epoxy resins; and alicyclic epoxy resins.
These may be used alone or in combination of two or more. Furthermore, epoxy resins modified with isocyanate or the like may also be used in combination.

From the viewpoints of handleability and heat resistance, the epoxy resin composition of this embodiment preferably contains a bisphenol-type epoxy resin as component (A) epoxy resin, and from the viewpoint of imparting sufficient mechanical properties, it preferably contains a bisphenol A-type epoxy resin.

When the epoxy resin composition of the present embodiment is formed into a film, from the viewpoints of (i) imparting appropriate adhesiveness during application, (ii) flexibility, (iii) ease of handling, and (iv) imparting sufficient mechanical strength, the epoxy equivalent of the entire epoxy resin (A), represented by the following formula (1), is preferably from 140 g/eq. to 500 g/eq., more preferably from 150 g/eq. to 450 g/eq., even more preferably from 160 g/eq. to 430 g/eq., and even more preferably from 170 g/eq. to 410 g/eq.
Epoxy equivalent of the entire epoxy resin of component (A) =
Total mass of epoxy resin ÷ Σ (mass of each epoxy resin / each epoxy equivalent) ... Equation (1)
When the epoxy equivalent of the entire epoxy resin (A) is 140 g/eq. or more and 500 g/eq. or less, the epoxy resin composition of the present embodiment has excellent handleability and high mechanical strength.
In the formula (1), "the entire epoxy resins of component (A)" includes both cases where component (A) contains two or more epoxy resins and cases where it contains only one epoxy resin. Furthermore, "each epoxy resin" means each epoxy resin that constitutes component (A), and includes both cases where it contains two or more epoxy resins and cases where it contains only one epoxy resin.
The epoxy equivalent of each epoxy resin constituting component (A) can be determined in accordance with JIS K7236.
The epoxy equivalent of the entire epoxy resin of component (A) can be controlled by using an epoxy resin having an epoxy equivalent within the above-mentioned range when only one epoxy resin is used, and when two or more epoxy resins are used, it can be controlled within the above-mentioned range by adjusting the epoxy equivalent of the epoxy resin used and the ratio of each epoxy resin added.

In the epoxy resin composition of the present embodiment, the content of the epoxy resin (A) is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and even more preferably 20% by mass or more, from the viewpoint of imparting sufficient curability.
Furthermore, from the viewpoint of blending component (B): a polymer different from component (A) described below in order to impart sufficient film-formability when forming a film, and component (C): a thermosetting agent described below in order to impart sufficient reactivity, the content of component (A): an epoxy resin is preferably 80% by mass or less, more preferably 75% by mass or less, even more preferably 70% by mass or less, and even more preferably 68% by mass or less.

(Component (B): Polymer different from component (A))
The epoxy resin composition of the present embodiment contains component (B): a polymer different from component (A) (hereinafter, may be referred to as (B) polymer or component (B)).
As the (B) polymer, a polymer that has the function of suppressing cracking, repelling, and excessive flow and maintaining the film shape when a predetermined resin composition containing the (B) polymer is formed into a film by casting or applying it to a certain thickness and drying it can be used.
Examples of the polymer (B) include, but are not limited to, phenoxy resin, polyvinyl butyral resin, polyvinyl acetal resin, polyacrylic resin, polyimide resin, polymaleimide resin, polyamideimide resin, and elastomers having a functional group such as a carboxyl group, a hydroxyl group, a vinyl group, or an amino group, or an aromatic ring.

Component (B) preferably contains a phenoxy resin, which has excellent long-term connection reliability with metal bodies.
Examples of phenoxy resins include, but are not limited to, bisphenol A phenoxy resins, bisphenol F phenoxy resins, bisphenol A-bisphenol F mixed phenoxy resins, bisphenol A-biphenyl mixed phenoxy resins, bisphenol A-bisphenol S mixed phenoxy resins, fluorene ring-containing phenoxy resins, and caprolactone-modified bisphenol A phenoxy resins.

The number average molecular weight of the (B) polymer is preferably 9,000 or more and 500,000 or less, more preferably 10,000 or more and 100,000 or less, even more preferably 11,000 or more and 50,000 or less, and even more preferably 12,000 or more and 30,000 or less.
The number average molecular weight is a polystyrene-equivalent number average molecular weight determined by gel permeation chromatography (hereinafter referred to as GPC), and is a value calculated as an average value in the range of polystyrene-equivalent molecular weights of 728 or more.
By ensuring that the number average molecular weight of the (B) polymer is 9,000 or more, sufficient film coatability can be imparted to the epoxy resin composition of the present embodiment, and the (B) polymer is less likely to slip through the crosslinked structure of the cured epoxy resin, which makes it possible to suppress a decrease in the cohesive strength of the cured product and a decrease in reliability.
On the other hand, by having a number average molecular weight of 500,000 or less, the epoxy resin composition of the present embodiment can maintain high adhesion to an adherend such as a substrate or an IC chip, and can also suppress the occurrence of localized curing defects during connection, making it difficult for corrosion of wiring and electrodes to occur, thereby achieving high insulation reliability.

The content of component (B) in the epoxy resin composition of the present embodiment is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and even more preferably 20% by mass or more, from the viewpoint of imparting sufficient film-forming properties and handleability to the epoxy resin composition of the present embodiment.
Furthermore, from the viewpoint of blending the component (A) epoxy resin in order to impart sufficient curability and adhesiveness during application, and the component (C) heat curing agent described below in order to impart sufficient reactivity, the content of component (B) is preferably 70% by mass or less, more preferably 60% by mass or less, even more preferably 55% by mass or less, and even more preferably 50% by mass or less.

(Component (C): Heat Curing Agent)
The epoxy resin composition of the present embodiment contains component (C) a heat curing agent (hereinafter, may be referred to as (C) heat curing agent or component (C)).
Examples of the (C) heat curing agent include, but are not limited to, amine-based curing agents, amide-based curing agents, phenol-based curing agents, acid anhydride-based curing agents, (C-2) active ester-based curing agents, catalyst-type curing agents, and latent curing agents.

Examples of the amine-based curing agent include, but are not limited to, aliphatic amines and aromatic amines.
Examples of aliphatic amines include, but are not limited to, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, isophoronediamine, 1,3-bisaminomethylcyclohexane, bis(4-aminocyclohexyl)methane, norbornenediamine, and 1,2-diaminocyclohexane.
Examples of aromatic amines include, but are not limited to, diaminodiphenylmethane, m-phenylenediamine, diaminodiphenylsulfone, diethyltoluenediamine, trimethylenebis(4-aminobenzoate), polytetramethylene oxide-di-p-aminobenzoate, KAYAHARD AA (manufactured by Nippon Kayaku Co., Ltd.), and Ethacure 100 (manufactured by Mitsui Chemicals Fine Co., Ltd.).

Examples of the amide-based curing agent include, but are not limited to, (C-3) dicyandiamide and its derivatives, such as guanidine-based compounds, or compounds in which an acid anhydride is added to an amine-based compound, and hydrazide-based compounds.
Examples of hydrazide compounds include, but are not limited to, succinic acid dihydrazide, adipic acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, p-oxybenzoic acid hydrazide, salicylic acid hydrazide, phenylaminopropionic acid hydrazide, and maleic acid dihydrazide.
Examples of guanidine compounds include, but are not limited to, dicyandiamide, methylguanidine, ethylguanidine, propylguanidine, butylguanidine, dimethylguanidine, trimethylguanidine, phenylguanidine, diphenylguanidine, and toluylguanidine.

The epoxy resin composition of this embodiment preferably contains (C-3) dicyandiamide as the (C) heat curing agent, from the viewpoint of maintaining excellent adhesive strength even after long-term storage when formed into a film, specifically, maintaining excellent metal adhesive strength even after storage at a temperature of 40°C for 7 days.

The mechanism by which the epoxy resin composition of the present embodiment, which contains dicyandiamide (C-3) as the heat curing agent (C), exhibits excellent metal adhesive strength even after storage at a temperature of 40°C for 7 days, is thought to be as follows, although it is not intended to be particularly limited thereto.
(C-3) dicyandiamide exists in the epoxy resin composition in a block state and exhibits curability by dissolving and diffusing during curing. The temperature at which (C-3) dicyandiamide dissolves and diffuses and exhibits reactive activity with epoxy groups is 100°C or higher, and therefore its reactivity with epoxy groups is suppressed at temperatures of 40°C, which is significantly lower than the reactive temperature. This prevents deterioration in the adhesiveness of a film made from the epoxy resin composition of this embodiment, as well as in molecular fluidity during curing, allowing for the development of good metal adhesion strength. Furthermore, because (C-3) dicyandiamide has four active hydrogens, the crosslinked structure formed after the reaction becomes dense, resulting in a stronger cured product and enabling the development of good metal adhesion strength.

Phenol-based curing agents include, but are not limited to, phenol novolac resin, cresol novolac resin, phenol aralkyl resin, cresol aralkyl resin, naphthol aralkyl resin, biphenyl-modified phenol resin, biphenyl-modified phenol aralkyl resin, dicyclopentadiene-modified phenol resin, aminotriazine-modified phenol resin, naphthol novolac resin, naphthol-phenol co-condensed novolac resin, naphthol-cresol co-condensed novolac resin, and allyl acrylic phenol resin.

Examples of acid anhydride curing agents include, but are not limited to, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

The epoxy resin composition of this embodiment preferably contains the active ester curing agent (C-2) as the heat curing agent (C), from the viewpoint of maintaining excellent properties even after long-term storage, specifically, maintaining excellent metal adhesive strength even after storage at a temperature of 40°C for 7 days.

The active ester curing agent (C-2) is not particularly limited as long as it functions as a curing agent for the epoxy resin (component (A)) and has an active ester group, but a compound having two or more active ester groups in one molecule is preferred.
From the viewpoint of the heat resistance and the like of the epoxy resin composition of the present embodiment, the active ester curing agent (C-2) is more preferably an active ester compound obtained by reacting a carboxylic acid compound and/or a thiocarboxylic acid compound with a hydroxy compound and/or a thiol compound, and even more preferably an active ester compound obtained by reacting a carboxylic acid compound with one or more compounds selected from a phenol compound, a naphthol compound, and a thiol compound.
Furthermore, it is even more preferable that the aromatic compound has two or more active ester groups in one molecule, which is obtained by reacting a carboxylic acid compound with an aromatic compound having a phenolic hydroxyl group.
Furthermore, it is even more preferable that the aromatic compound is an aromatic compound obtained by reacting a compound having at least two carboxylic acids in one molecule with an aromatic compound having a phenolic hydroxyl group, and that the aromatic compound has two or more active ester groups in one molecule.

The compound constituting the active ester curing agent (C-2) may be either linear or multi-branched. Furthermore, if the compound having at least two or more carboxylic acids in one molecule contains an aliphatic chain, the active ester curing agent (C-2) will have high compatibility with the epoxy resin (A). Furthermore, if the active ester curing agent (C-2) is a compound having an aromatic ring, the heat resistance of the epoxy resin composition of this embodiment can be improved.

Carboxylic acid compounds used to form the (C-2) active ester curing agent include, but are not limited to, benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. In particular, from the viewpoint of the heat resistance of the epoxy resin composition of this embodiment, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, and terephthalic acid are preferred, with isophthalic acid and terephthalic acid being more preferred.

(C-2) Examples of thiocarboxylic acid compounds used to form the active ester curing agent include, but are not limited to, thioacetic acid and thiobenzoic acid.

Examples of the phenol compound or naphthol compound used to form the (C-2) active ester curing agent include, but are not limited to, hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalene, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, benzenetriol, dicyclopentadienyl diphenol, and phenol novolak.
In particular, from the viewpoint of the heat resistance of the epoxy resin composition of the present embodiment and the solubility of the active ester-based curing agent (C-2), bisphenol A, bisphenol F, bisphenol S, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadienyldiphenol, and phenol novolak are preferred, and catechol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadienyldiphenol, and phenol novolak are preferred. Benzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadienyl diphenol, and phenol novolac are more preferred, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, dicyclopentadienyl diphenol, and phenol novolac are even more preferred, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, dicyclopentadienyl diphenol, and phenol novolac are even more preferred, and dicyclopentadienyl diphenol and phenol novolac are still more preferred, with dicyclopentadienyl diphenol being particularly preferred.

(C-2) Examples of thiol compounds used to form the active ester curing agent include, but are not limited to, benzenedithiol, triazinedithiol, etc.

The active ester compound constituting the active ester curing agent (C-2) may be used alone or in combination of two or more.
As the active ester compound constituting the active ester curing agent (C-2), the active ester compounds disclosed in JP-A-2004-277460 may be used, or commercially available compounds may also be used.
Commercially available active ester compounds include, but are not limited to, those containing a dicyclopentadienyldiphenol structure, acetylated phenol novolac, and benzoated phenol novolac, and more preferably those containing a dicyclopentadienyldiphenol structure. Examples of those containing a dicyclopentadienyldiphenol structure include, but are not limited to, EXB9451, EXB9460, EXB9460S, and HPC-8000-65T (manufactured by DIC Corporation), DC808 (manufactured by Japan Epoxy Resins Co., Ltd.) as an acetylated phenol novolac, and YLH1026 (manufactured by Japan Epoxy Resins Co., Ltd.) as a benzoated phenol novolac.

As described above, it is preferable that the epoxy resin composition of this embodiment contains (C-2) an active ester curing agent as component (C) the heat curing agent, from the viewpoint of maintaining excellent metal adhesive strength even after storage at a temperature of 40°C for 7 days.

The mechanism by which the inclusion of (C-2) an active ester curing agent as component (C) enables excellent metal bond strength to be maintained even after storage at a temperature of 40°C for 7 days is thought to be, but is not intended to be particularly limited to, the following.
The reaction activation temperature of the active ester curing agent (C-2) is at least 50°C higher than 40°C. Therefore, under the temperature condition of 40°C, the reactivity with the epoxy groups of the epoxy resin (A) is suppressed. As a result, the adhesiveness of the film made of the epoxy resin composition of this embodiment and the molecular fluidity during curing are not deteriorated, and good metal adhesive strength can be exhibited.

The catalyst type curing agent is not limited to the following, but examples thereof include cationic thermosetting catalysts, BF ₃ -amine complexes, and the like.

Examples of the latent curing agent include, but are not limited to, imidazole compounds, amine adduct compounds, and (C-1) microcapsule-type curing agents obtained by coating these compounds, and curing agents adsorbed on a porous body.
In particular, from the viewpoint of achieving both storage stability and reactivity, the epoxy resin composition of the present embodiment preferably contains a microcapsule-type curing agent (C-1) as the heat curing agent (C).

Imidazole compounds include, but are not limited to, imidazoles such as imidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-aminoethyl-2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-ethyl-4-methylimidazole, 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazole, and 1-(2-hydroxy-3-butoxypropyl)-2-ethyl-4-methylimidazole, as well as compounds obtained by reacting these imidazoles with at least one selected from the group consisting of carboxylic acid compounds, sulfonic acid compounds, urea compounds, isocyanate compounds, and epoxy resins.

Examples of the amine-based adduct compound include compounds obtained by reacting at least one selected from the group consisting of carboxylic acid compounds, sulfonic acid compounds, urea compounds, isocyanate compounds, and epoxy resins with the amine-based curing agent.

Examples of latent curing agents include, but are not limited to, Novacure HX-3742, HX-3921HP, HXA3932HP, HXA9322HP, HXA9382HP, and LSA-H2104 (manufactured by Asahi Kasei Corporation), Amicure PN-23, PN-23J, PN-40, PN-40J, PN-H, and MY-24 (manufactured by Ajinomoto Fine-Techno Co., Ltd.), and Fujicure FXR-1020 and FXR-1030 (manufactured by Fuji Chemical Industry Co., Ltd.).

From the viewpoint of storage stability of the epoxy resin composition of the present embodiment, it is preferable that the component (C) heat curing agent contained in the epoxy resin composition of the present embodiment contains a solid curing agent.
In this specification, being solid means being solid at 25°C and 1013 hPa.
A solid curing agent is dispersed in the epoxy resin composition of the present embodiment, and a curing reaction is initiated at a predetermined temperature and after a predetermined time has elapsed since the start of heating. This allows the epoxy resin composition of the present embodiment to have both reactivity and storage stability.
.
Examples of the solid curing agent include dicyandiamide, solid imidazole compounds, solid polyamine compounds, and microcapsule-type curing agents (C-1) containing these compounds.
Here, from the viewpoint of being able to achieve particularly excellent storage stability by physically separating the component (C) heat curing agent and the component (A) epoxy resin with a capsule membrane, it is preferable that the (C) heat curing agent contains a (C-1) microcapsule-type curing agent, and from the viewpoint of achieving both storage stability and reactivity, it is more preferable that the (C-1) microcapsule-type curing agent is a microcapsule-type curing agent containing an imidazole-based compound.
Furthermore, the epoxy resin composition of this embodiment preferably uses the microcapsule-type curing agent (C-1) in combination with a monofunctional epoxy compound having an aromatic ring (D), which will be described later, from the viewpoint of improving the stability (suppression of thickening) of the epoxy resin composition of this embodiment in a varnish state before it is formed into a film, i.e., from the viewpoint of suppressing elution of the core curing agent component due to damage caused by the solvent to the capsule membrane in the varnish state, and from the viewpoint of improving resistance to solvents in the drying step during film formation, i.e., from the viewpoint of suppressing elution of the core component due to damage caused by the solvent to the capsule membrane during solvent evaporation at high temperatures in the drying step (when the solvent is present around the microcapsules).
Examples of microencapsulated curing agents obtained by microencapsulating a solid curing agent containing an imidazole compound include, but are not limited to, Novacure HX-3742, HX-3921HP, HXA3932HP, HXA9322HP, HXA9382HP, and LSA-H2104 (manufactured by Asahi Kasei Corporation).

The content of the component (C) heat curing agent in the epoxy resin composition of the present embodiment is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 3% by mass or more, and even more preferably 5% by mass or more, from the viewpoints of the component (C) heat curing agent exhibiting sufficient reactivity with the component (A) epoxy resin and imparting sufficient strength to the resulting cured product.
Furthermore, from the viewpoint of imparting sufficient film-forming properties and adhesiveness when applied, the content of component (A) epoxy resin and component (B) polymer can be added, and from the viewpoint of suppressing brittleness of the cured product, the content of (C) thermosetting agent is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 41% by mass or less.

(Component (D): Monofunctional Epoxy Compound Having an Aromatic Ring)
The epoxy resin composition of the present embodiment can contain component (D), a monofunctional epoxy compound having an aromatic ring (hereinafter, sometimes referred to as component (D)).
In particular, as described above, by using the microcapsule-type curing agent (C-1) in combination with component (D), the stability (suppression of thickening) in the varnish state before film formation can be improved, i.e., the varnish state can be prevented from the elution of the core curing agent component due to the solvent damaging the capsule membrane.Furthermore, the resistance to solvents in the drying step during film formation can be improved, i.e., the high temperature in the drying step can be prevented from the solvent damaging the capsule membrane during the solvent evaporation (when the solvent is present around the microcapsules), which can prevent the elution of the core component.
Examples of the monofunctional epoxy compound having an aromatic ring as component (D) include, but are not limited to, styrene oxide, phenyl glycidyl ether, cresyl glycidyl ether, p-sec-butylphenyl glycidyl ether, t-butylphenyl glycidyl ether, and compounds such as SY-OPG (trade name) manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.

Furthermore, it is preferable that the epoxy resin composition of this embodiment contains both component (D), a monofunctional epoxy resin having an aromatic ring, and component (C-1), a microcapsule-type curing agent, from the viewpoints of reducing the consumption rate of epoxy groups during storage when stored in film form at a temperature of 40°C for 7 days, reducing the rate of decrease in metal bond strength, and maintaining excellent metal bond strength after storage at a temperature of 40°C for 7 days.

The mechanism by which the above-mentioned effects are exhibited by including both component (D), a monofunctional epoxy resin having an aromatic ring, and component (C-1), a microcapsule-type curing agent, is thought to be as follows, although it is not intended to be limiting.
When component (D) is incorporated into the shell of the microcapsule-type curing agent (C-1), a stacking effect between aromatic rings is exerted within the shell to form a network, thereby increasing the cohesive strength of the shell. Therefore, by constructing a shell that is resistant to swelling in solvents, it is possible to reduce the elution of the curing agent component out of the shell in the varnish state before film coating and when the film is dried, and as a result, it is possible to suppress the formation of high molecular weight substances and crosslinked structures during film storage, thereby reducing the rate of decrease in metal adhesive strength after storing the epoxy resin composition in a film form at 40°C for 7 days and maintaining the metal adhesive strength after storing at 40°C for 7 days.
In this case, since component (D) is a monofunctional compound, steric hindrance is small, so that it can easily penetrate into the interior of the shell, and a stacking network of aromatic rings can be formed simultaneously over a denser and wider area. From the viewpoint of suppressing steric hindrance, it is preferable that the aromatic ring of component (D) is a monocyclic ring, and the number of carbon atoms of each substituent is preferably 3 or less.

As a method for incorporating the component (D) monofunctional epoxy compound having an aromatic ring and the (C-1) microcapsule-type curing agent into the epoxy resin composition of the present embodiment, for example, any of the following methods can be used: (1) a method using a masterbatch (C-1) microcapsule-type curing agent containing component (D); (2) a method using a (C-1) microcapsule-type curing agent not containing component (D) or a masterbatch (C-1) microcapsule-type curing agent to which component (D) has been added; or (3) a method of blending component (D), the (C-1) microcapsule-type curing agent, and other components in the stage of preparing a coating liquid.
Here, from the viewpoint of being able to efficiently form a wide and strong stacking network within the shell by causing the component (D) and the microcapsule-type curing agent (C-1) to coexist at a high concentration, a method using the microcapsule-type curing agent (C-1) in the form of a masterbatch containing the component (D) (1) is preferred.
An example of the masterbatch-formed microcapsule-type curing agent (C-1) containing the component (D) is LSA-H2104 (manufactured by Asahi Kasei Corporation).

The content of component (D), a monofunctional epoxy compound having an aromatic ring, in the epoxy resin composition of this embodiment is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.3% by mass or more, of the solid content used to prepare the epoxy resin composition of this embodiment, from the viewpoint of fully exhibiting solvent resistance. Also, from the viewpoint of preventing deterioration in storage stability due to excessive addition and preventing deterioration in the mechanical strength of the cured product, the content is preferably 4% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less.
Furthermore, when a masterbatch microcapsule-type curing agent (C-1) containing component (D) is used, the content of component (D) in the masterbatch microcapsule-type curing agent (C-1) is preferably 3% by mass or more, more preferably 4% by mass or more, even more preferably 5% by mass or more, and even more preferably 6% by mass or more, from the viewpoint of exhibiting sufficient solvent resistance. Furthermore, from the viewpoint of maintaining good storage stability of the masterbatch microcapsule-type curing agent (C-1) and the epoxy resin composition of this embodiment, the content of component (D) is preferably 15% by mass or less, more preferably 14% by mass or less, even more preferably 13% by mass or less, and even more preferably 12% by mass or less.

(Other additives)
In addition to the above-described components (A) to (D), the epoxy resin composition of the present embodiment may further contain additives such as organic fillers, inorganic fillers, pigments, dyes, flow control agents, thickeners, release agents, wetting agents, flame retardants, surfactants, acrylate monomers, and photopolymerization initiators.

The organic filler functions as an impact buffer, capable of mitigating stress generated by an impact.
By including an organic filler, the epoxy resin composition of the present embodiment can further improve adhesion to various connecting members and also tends to suppress the occurrence and propagation of fillet cracks.
Examples of organic fillers include, but are not limited to, organic fine particles of acrylic resin, silicone resin, butadiene rubber, polyester, polyurethane, polyvinyl butyral, polyarylate, polymethyl methacrylate, acrylic rubber, polystyrene, NBR, SBR, silicone-modified resin, and copolymers containing any of these as components.
From the viewpoint of improving adhesiveness, preferred examples of the organic filler include an alkyl (meth)acrylate-butadiene-styrene copolymer, an alkyl (meth)acrylate-silicone copolymer, a silicone-(meth)acrylic copolymer, a complex of silicone and (meth)acrylic acid, a complex of alkyl (meth)acrylate-butadiene-styrene and silicone, and a complex of alkyl (meth)acrylate and silicone.
The organic filler may also have a core-shell structure, with the core and shell layers having different compositions. Examples of the core-shell organic filler include particles having a silicone-acrylic rubber core to which an acrylic resin is grafted, and particles having an acrylic resin grafted to an acrylic copolymer.
These organic fillers may be used alone or in combination of two or more.

The inorganic filler has the function of adjusting the thermal expansion coefficient of the epoxy resin composition of the present embodiment, and therefore, by including the inorganic filler, the heat resistance and moisture resistance of the epoxy resin composition of the present embodiment when used as an underfill material tend to be improved.
Examples of inorganic fillers include, but are not limited to, silicates such as talc, calcined clay, uncalcined clay, mica, and glass; oxides such as silica oxides such as titanium oxide, aluminum oxide (alumina), fused silica (fused spherical silica, fused crushed silica), synthetic silica, and crystalline silica; carbonates such as calcium carbonate, magnesium carbonate, and hydrotalcite; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; sulfates such as barium sulfate and calcium sulfate; sulfites such as calcium sulfite; borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate; and nitrides such as aluminum nitride, boron nitride, and silicon nitride.
Among these, fused silica, crystalline silica, and synthetic silica powder are preferred from the viewpoint of improving heat resistance, moisture resistance, and strength, and silicon oxide, aluminum oxide, and boron nitride are preferred from the viewpoint of obtaining similar effects. Use of these materials can suppress the coefficient of linear thermal expansion, which is expected to improve thermal cycle tests, etc.
The shape of the inorganic filler is not particularly limited, and may be, for example, any of amorphous, spherical, and flaky shapes.
These inorganic fillers may be used alone or in combination of two or more.

Pigments include, but are not limited to, kaolin, aluminum oxide trihydrate, aluminum hydroxide, chalk powder, gypsum, calcium carbonate, antimony trioxide, pentone, silica, aerosol, lithopone, baryte, titanium dioxide, etc.

Dyes include, but are not limited to, natural dyes such as plant-derived dyes such as madder and indigo, mineral-derived dyes such as yellow ochre and red clay, synthetic dyes such as alizarin and indigo, and fluorescent dyes.

Examples of flow control agents include, but are not limited to, organic silane compounds such as silane coupling agents; organic titanium compounds such as titanium tetraisopropoxide and titanium diisopropoxybis(acetylacetonate); and organic zirconium compounds such as zirconium tetra-n-butoxide and zirconium tetraacetylacetonate.

Thickeners include, but are not limited to, animal-based thickeners such as gelatin; plant-based thickeners such as polysaccharides and cellulose; and chemically synthesized thickeners such as polyacrylic thickeners, modified polyacrylic thickeners, polyether thickeners, urethane-modified polyether thickeners, and carboxymethyl cellulose.

Releasing agents include, but are not limited to, fluorine-based releasing agents, silicone-based releasing agents, and acrylic-based releasing agents made from a copolymer of glycidyl (meth)acrylate and a linear alkyl (meth)acrylate ester having 16 to 22 carbon atoms.

Wetting agents include, but are not limited to, unsaturated polyester copolymer wetting agents having acidic groups, such as acrylic polyphosphate esters.

Flame retardants include, but are not limited to, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, halogen-based flame retardants such as chlorine compounds and bromine compounds, phosphorus-based flame retardants such as condensed phosphate esters, antimony-based flame retardants such as antimony trioxide and antimony pentoxide, and inorganic oxides such as silica fillers.

Surfactants include, but are not limited to, anionic surfactants such as alkylbenzene sulfonates and alkyl polyoxyethylene sulfates, cationic surfactants such as alkyldimethylammonium salts, amphoteric surfactants such as alkyldimethylamine oxides and alkylcarboxybetaines, and nonionic surfactants such as linear alcohols and fatty acid esters having 25 or more carbon atoms.

Acrylate monomers include, but are not limited to, compounds having (meth)acryloyl groups at both ends of a polyalkylene oxide, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polybutylene glycol di(meth)acrylate, trimethylolpropane-type multifunctional (meth)acrylate, pentaerythritol-type multifunctional (meth)acrylate, dipentaerythritol-type multifunctional (meth)acrylate, di(meth)acrylate having a bisphenol A structure, and di(meth)acrylate having a dicyclopentadiene structure.

Examples of photopolymerization initiators include, but are not limited to, acylphosphine oxides such as bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (BASF's Irgacure 819) and 2,4,6-trimethylbenzoyldiphenylphosphine oxide (BASF's Irgacure TPO), oximes such as 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime) (BASF's Irgacure OXE01) and 1-[6-(2-methylbenzoyl)-9-ethyl-9H-carbazol-3-yl]ethanone-O-acetyloxime (BASF's Irgacure OXE02), and sensitizers having an aromatic ring.

[Method for preparing epoxy resin composition]
The epoxy resin composition of the present embodiment can be prepared, for example, by mixing component (A) an epoxy resin, component (B): a polymer different from component (A), component (C): a thermosetting agent, and, if necessary, component (D): a monofunctional epoxy compound having an aromatic ring, and other additives, and mixing the mixture in a planetary mixer or the like.

[Method for preparing an epoxy resin composition preparation for producing a film-shaped epoxy resin composition]
[0033] Examples of methods for preparing an epoxy resin composition preparation for forming a film-shaped epoxy resin composition include a method in which component (A): an epoxy resin, component (B): a polymer different from component (A), component (C): a thermosetting agent, and, if necessary, component (D): a monofunctional epoxy compound having an aromatic ring, and other additives are mixed, an organic solvent is further added, and the mixture is mixed using a planetary mixer or the like.
The organic solvent is not particularly limited, and known organic solvents can be used, including, but not limited to, hydrocarbons such as toluene, xylene, cyclohexane, mineral spirits, and solvent naphtha; ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK); esters such as ethyl acetate, n-butyl acetate, and propylene glycol monomethyl ethyl ether acetate; alcohols such as methanol, isopropanol, n-butanol, butyl cellosolve, and butyl carbitol; and amide solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone.

[Film-shaped epoxy resin composition]
In one preferred embodiment, the epoxy resin composition of the present embodiment is in the form of a film.
The film-shaped epoxy resin composition has a predetermined support and an epoxy resin composition layer formed on the support using the above-mentioned epoxy resin composition preparation liquid.
The film-shaped epoxy resin composition of the present embodiment may have a protective layer on the surface of the epoxy resin composition layer opposite to the support, if necessary.

(Support)
The support is preferably a material that can withstand the temperature during drying of the organic solvent, and examples of such a support include, but are not limited to, polyethylene terephthalate film, polyvinyl alcohol film, polyvinyl chloride film, vinyl chloride copolymer film, polyvinylidene chloride film, vinylidene chloride copolymer film, polymethyl methacrylate copolymer film, polystyrene film, polyacrylonitrile film, styrene copolymer film, polyamide film, and cellulose derivative film.
These supports may be stretched as required.

(protective layer)
The protective layer is preferably made of a material capable of sufficiently maintaining the surface smoothness of the epoxy resin composition layer, and examples of such a protective layer include, but are not limited to, polyethylene film, polypropylene film, polyethylene terephthalate film treated for easy peeling, and oriented polypropylene film.

(Method for producing a film-shaped epoxy resin composition)
The film-shaped epoxy resin composition of the present embodiment can be produced by sequentially laminating a support, an epoxy resin composition layer, and, if necessary, a protective layer.
As a method for laminating the support, the epoxy resin composition layer, and the protective layer, a known method can be adopted.
For example, an epoxy resin composition preparation liquid is prepared by the above-mentioned method, and then first coated on a support using a known method such as an applicator or a bar coater, followed by drying to form an epoxy resin composition layer on the support. Next, if necessary, a protective layer is laminated on the epoxy resin composition layer, thereby producing an epoxy resin composition in the form of a film.

(Epoxy group consumption rate (%) during storage when a film-shaped epoxy resin composition is stored at 40°C for 7 days)
When the epoxy resin composition of the present embodiment is stored in the form of a film at a temperature of 40°C for 7 days, the epoxy group consumption rate during the storage period is 0% or more and 30% or less.
When the epoxy group consumption rate under the above-mentioned conditions is within the above-mentioned range, deterioration of film adhesion due to the formation of polymers or crosslinking and deterioration of molecular fluidity during thermal curing can be suppressed, and even after storing the film-shaped epoxy resin composition under the above-mentioned conditions, a decrease in adhesive strength to metal can be effectively suppressed compared to before storage.

The composition is stored at a temperature of 40°C for 7 days, and examples of a method for controlling the consumption rate of epoxy groups during the storage period to 0% or more and 30% or less include, but are not limited to, the following methods (1) to (3).
(1): Component (C) is a thermal curing agent that contains at least a first curing agent having a reaction activation temperature of 80°C or higher and a second curing agent that promotes the reaction of the first curing agent, and the second curing agent is a non-microencapsulated solid curing agent that is insoluble in the solvent used to prepare the varnish.
The term "insoluble" means that the concentration of solids dissolved in the solvent after adding the second curing agent to the solvent and stirring at 25°C for 5 minutes is less than 3% by mass.
Examples of the first curing agent include, but are not limited to, guanidine-based compounds, phenolic resin-based curing agents, and active ester-based curing agents. Dicyandiamide and active ester-based curing agents are preferred from the viewpoints of excellent stability and excellent physical properties of the resulting cured product.
The second curing agent may be a solid latent curing agent, and from the viewpoint of excellent stability, a solid amine-based latent curing agent is preferred. Examples of the second curing agent include, but are not limited to, solid amine compounds such as Amicure PN40 and PN40J. Furthermore, the amount of the second curing agent added is preferably 0.5 to 7, more preferably 1 to 6, and even more preferably 1.5 to 5, based on the amount of component (A): epoxy resin taken as 100, from the viewpoint of the balance between storage stability and reactivity.
(2): Component (C) the heat curing agent contains (C-1) the microcapsule-type curing agent and component (D) the monofunctional epoxy compound having an aromatic ring.
Furthermore, when a curing agent component is further added as the (C) thermosetting agent, it is preferable to add a curing agent having a reaction activation temperature of 80° C. or higher. Examples of such curing agents include, but are not limited to, guanidine-based compounds, phenolic resin-based curing agents, and active ester-based curing agents. Dicyandiamide and active ester-based curing agents are preferred from the viewpoints of excellent stability and excellent physical properties of the resulting cured product.
(3) In addition to the method described in (1) and (2), the epoxy equivalent of the entire epoxy resin (A) is adjusted to 140 g/eq. or more and 500 g/eq. or less.
As a result, when the composition is stored at a temperature of 40°C for 7 days, the consumption rate of the epoxy groups during the storage period can be controlled to be lower.

(Specific embodiment of film-shaped epoxy resin composition)
The film-shaped epoxy resin composition of the present embodiment can be used as, for example, an interlayer insulating film, a film-type solder resist, a die attach film, a sealing sheet, an adhesive sheet, a conductive film, an anisotropic conductive film, a thermally conductive film, and the like, although not limited thereto.

[Cured product]
The cured product of the present embodiment is a cured product of the epoxy resin composition of the present embodiment, and can be produced by curing the epoxy resin composition of the present embodiment.
The curing method includes, but is not limited to, heating in an oven and thermocompression bonding. Specifically, the film-like epoxy resin composition of the present embodiment may be heat-cured during the manufacturing process of various electronic components or the like incorporating the film-like epoxy resin composition of the present embodiment.
The conditions for thermally curing the epoxy resin composition of the present embodiment are not particularly limited and can be appropriately selected depending on the composition of the epoxy resin composition and the like.
The cured product of the present embodiment has excellent reliability and can satisfactorily perform functions such as adhesion and sealing when used as an adhesive or sealant for various electronic components, etc. The mechanism behind this is thought to be, but is not intended to be limiting, as follows.
The epoxy resin composition of this embodiment has excellent stability, which allows the epoxy group reaction rate during drying to be kept low. Therefore, it softens when heated in the early stages of curing, allowing it to conform well to the irregularities of the adherend. Furthermore, the thermosetting agent (C) has excellent reactivity during curing, allowing it to cure rapidly while maintaining the desired adhesive surface area.
As a result, a cured product can be obtained that is free of voids between the adherend and the cured product and free of any extrusion defects.
Furthermore, even after storage, the film can be cured in the same manner as before storage, and the cured product can perform the functions of adhesion, sealing, etc., satisfactorily.

[Structure]
The structure of this embodiment includes a metal substrate and the cured product of this embodiment.
Examples of metal substrates include semiconductor chips having metal wires, bumps, solder balls, etc., laminates and interlayer insulating materials having metal layers, wiring boards having metal wiring, flexible substrates, metal pieces, motor coils, etc.
The structure of the present embodiment can be produced by placing the epoxy resin composition of the present embodiment in contact with the exposed metal portion of the metal substrate, and optionally subjecting it to heating, pressure, leaving it for a predetermined period of time, impregnation, drying, etc., followed by thermal curing under heating conditions suited to the composition.
According to the structure of this embodiment, it is possible to obtain electronic parts, automobile parts, etc. that have few voids and have high adhesive strength between the metal and the epoxy resin composition.

[Electronic Components]
The electronic component of the present embodiment is formed by combining one or more components selected from the group consisting of a semiconductor element, a flexible substrate, a printed wiring board, a power semiconductor, and a solar panel, which include the cured product of the present embodiment.
These can be produced by forming the cured product of this embodiment on a predetermined member.
The electronic component of this embodiment has no voids and the metal portion and the resin are firmly bonded together, and therefore exhibits long-term reliability, long-term stability under high-temperature and high-humidity conditions, and low water permeability.

Hereinafter, the present embodiment will be described with reference to specific examples and comparative examples, but the present embodiment is not limited to the following examples and comparative examples.
In the following, "parts" and "%" are by mass unless otherwise specified.

[Preparation of a film-shaped epoxy resin composition]
Components (A) to (C) were weighed according to Tables 1 and 2 below, and methyl ethyl ketone (MEK) was further added as a solvent so that the solid content in the varnish was in the range of 30% by mass to 70% by mass, thereby obtaining a formulation.
The compound was mixed in a non-bubbling kneader placed in a 25°C environment, with stirring for 2 minutes and degassing for 3 minutes, to obtain a liquid preparation of an epoxy resin composition.
The prepared liquid was applied onto a polyethylene terephthalate film (thickness: 50 μm) as a support so as to give a dry film thickness of 40 μm.
Thereafter, the film was dried by heating in an oven preheated to 120°C for 5 minutes, and the surface opposite the support was protected with a polyethylene terephthalate film that had been treated for easy peeling, to obtain an epoxy resin composition in the form of a film.

[Methods for measuring physical properties and evaluating characteristics]
(Epoxy group consumption rate (%) during storage at a temperature of 40°C for 7 days) The FT-IR spectrum of the film-shaped epoxy resin composition was measured using a Fourier transform infrared spectrophotometer (FT/IR-6600, manufactured by JASCO Corporation).
The intensity ratio _P20 / _P10 of the absorption _P10 at around 2920 cm ^-1 due to the methylene groups of the epoxy resin and phenoxy resin, which did not change in strength after heat drying, to the absorption _P20 at around 915 cm ^-1 due to the epoxy groups was calculated, and this was used as the intensity indicating the amount of epoxy groups before storage.
The state before storage at a temperature of 40°C for 7 days was defined as the initial state.
Next, the film-shaped epoxy resin composition was stored in an oven at a temperature of 40°C for 7 days, and then the absorption _P2A near 915 cm ^-1 was measured using the absorption _P1A near 2920 cm ^-1 as the reference in the same manner as above, and the intensity ratio _P2A / _P1A was calculated.
From the obtained values, the epoxy group consumption rate (%) during storage (PD.R.) when stored for 7 days at a temperature of 40°C was calculated using the following formula (3).
PD. R. (%)=(1-(P _2A /P _1A )/(P ₂₀ /P ₁₀ ))×100...Formula (3)

(Epoxy equivalent of the entire epoxy resin of component (A))
The epoxy equivalent of each of the epoxy resins listed below was determined in accordance with JIS K7236.
From the obtained epoxy equivalent, the epoxy equivalent of the entire epoxy resin component (A) was calculated using the following formula (1).
Epoxy equivalent of all epoxy resins in component (A) = total mass of epoxy resins ÷ Σ (mass of each epoxy resin / each epoxy equivalent) ... Equation (1)

(Metal adhesive strength and rate of decrease in metal adhesive strength after storing a film-shaped epoxy resin composition at 40°C for 7 days)
The film-shaped epoxy resin composition was cut into a size of 25 mm x 5 mm, and after peeling off the protective film, the support was placed and fixed between two copper plates ("C1100P" manufactured by Standard Test Piece Co., Ltd.).
In this state, the film was heated in an oven at 60° C. for 10 minutes to transfer the film material onto the copper plate, and then the support was peeled off.
Next, the epoxy resin composition layer was again sandwiched and fixed between two copper plates, and heated in an oven preheated to 180° C. for 1 hour to heat cure and bond the layers together, thereby obtaining a test specimen.
The tensile shear adhesive strength (N/ ^mm2 ) of the obtained test pieces was measured using an AUTOGRAPH AGS-X 5kN (manufactured by Shimadzu Corporation) in a constant temperature and humidity room at 23°C and 50% RH, and the median of the obtained values was used as the initial value S0 (N/ ^mm2 ) of the metal adhesive strength.
Furthermore, the film-shaped epoxy resin composition prepared by the above method was stored in an oven at a temperature of 40°C for 7 days, and then the metal adhesive strength was measured in the same manner as above, and this was taken as the metal adhesive strength SA (N/ ^mm2 ) after storage at a temperature of 40°C for 7 days.
From the obtained adhesive strength values, the metal adhesive strength reduction rate (SDR) after storing the film-shaped epoxy resin composition at a temperature of 40°C for 7 days was calculated using the following formula (4), with the metal adhesive strength before storage as the reference.
S.D. R. (%)= (1-(SA/S0))×100...Formula (4)
The smaller the SD.R, the lower the rate of decrease from the initial value was judged to be, and the evaluation was made according to the following criteria.
Less than 5% ◎
5% or more but less than 15% 〇 15% or more but less than 30% △
Over 30% ×

[Ingredients]
Components (A) to (C) in Tables 1 and 2 below are shown below.
(Component (A): Epoxy resin)
・jER828 (Mitsubishi Chemical Corporation)
Bisphenol A type epoxy resin Epoxy equivalent 184 g/eq.
・HP-4032D (DIC Corporation)
Naphthalene type epoxy resin, epoxy equivalent 140g/eq
・jER4007P (manufactured by Mitsubishi Chemical Corporation)
Solid bisphenol F type epoxy resin, epoxy equivalent weight 2250 g/eq.

(Component (B): Polymer different from component (A))
・PKHB (Gabriel Phenoxies)
Phenoxy resin, number average molecular weight in the region of polystyrene equivalent molecular weight of 728 or more: 14,600

(Component (C): Heat Curing Agent)
DICY: Dicyandiamide (manufactured by Wako Pure Chemical Industries, Ltd.)
・LSA-H2104 (manufactured by Asahi Kasei Corporation)
A masterbatch microcapsule-type curing agent in which a solid microcapsule-type curing agent containing an imidazole-based compound is dispersed in an epoxy resin containing phenyl glycidyl ether (10% by mass). Epoxy resin curing agent VI of Patent No. 6619628
Masterbatch microcapsule curing agent containing no phenyl glycidyl ether: HPC-8000-65T (DIC Corporation)
Aromatic ring-containing activated ester resin, solid content 65%, toluene solution, Amicure PN-40 (Ajinomoto Fine-Techno Co., Ltd.)
Amine compound that is solid at 25°C: 2-ethyl-4-methylimidazole (Tokyo Chemical Industry Co., Ltd.)

[Examples 1 to 11], [Comparative Examples 1 to 4]
Each component was blended in the proportions shown in Tables 1 and 2, and a film-shaped epoxy resin composition was prepared by the method described above.
The physical properties and characteristics of the prepared film-shaped epoxy resin composition were measured and evaluated by the above-mentioned methods.

Comparing the Examples and Comparative Examples, it was found that when the epoxy group consumption rate during storage at 40°C for 7 days was 30% or less, the rate of decrease in metal bond strength after storage at 40°C for 7 days was small, based on the metal bond strength before storage.
Furthermore, when Examples 3 and 4 were compared with Example 5, Example 6 with Example 7, Example 8 with Example 9, and Example 10 with Example 11, it was found that when a microcapsule-type curing agent and a monofunctional epoxy compound having an aromatic ring were contained, the film-shaped epoxy resin composition had high metal adhesive strength after storage at 40°C for 7 days and was highly stable during the storage period. In other words, by containing a microcapsule-type curing agent and a monofunctional epoxy compound having an aromatic ring, a high balance between stability and reactivity could be achieved.
Furthermore, when Example 1 was compared with Examples 3 and 4, and Example 1 with Example 8, it was found that when an active ester curing agent or dicyandiamide was contained, the film-shaped epoxy resin composition had a high metal adhesive strength after storage at 40°C for 7 days.

[Relationship between epoxy group consumption rate Y and epoxy equivalent X of the entire epoxy resin]
FIG. 1 shows a plot of Examples 1 to 11, with the horizontal axis representing the epoxy equivalent (g/eq.) of the entire epoxy resin (A) represented by the following formula (1): X, and the vertical axis representing the consumption rate PD.R. (%) of the epoxy groups during storage at 40°C for 7 days: Y.
Epoxy equivalent of all epoxy resins in component (A) = total mass of epoxy resins ÷ Σ (mass of each epoxy resin / each epoxy equivalent) ... Equation (1)

From Figure 1, it can be seen that when the epoxy equivalent (g/eq.) of the entire epoxy resin of component (A) represented by formula (1): X and the consumption rate of epoxy groups during storage at 40°C for 7 days, PD.R. (%): Y, satisfy the following formula (2), the rate of decrease in metal adhesive strength after storage of a film-shaped epoxy resin composition at 40°C for 7 days is small, based on the metal adhesive strength before storage.
Y(%)≦−0.06×X+39 Formula (2)

When the film-shaped epoxy resin composition satisfies the formula (2), the mechanism by which the above properties are exhibited is thought to be as follows, although it is not intended to be particularly limited thereto.
The decrease in adhesive strength after long-term storage is due to the reaction of epoxy groups during storage, resulting in the formation of high molecular weight compounds and crosslinked structures, which reduces the fluidity of the film when it is applied or when it is thermally cured, resulting in (i) a decrease in the adhesive area due to a deterioration in conformity to the substrate, and (ii) a decrease in the mobility of compounds having functional groups with metal-coordinating properties, such as amino groups, to the metal interface.
The bond network formed by the polymers and crosslinked structures depends greatly on "what epoxy equivalent compounds reacted to what extent." In this example, good reduction in adhesive strength was confirmed in Example 5, in which the epoxy equivalent of the entire component (A) was 184 g/eq. and the epoxy group consumption rate Y was 28%, and in Example 11, in which the epoxy equivalent of the entire component (A) was 410 g/eq. and the epoxy group consumption rate Y was 14%.
Here, when the epoxy equivalent of component (A) is 184 g/eq. or more and 410 g/eq. or less, the properties of the polymer and crosslinked structure in the bond network that is formed are between those of Example 5 and Example 11, and it is unlikely that a significant decrease in adhesive strength will occur due to consumption of a small amount of epoxy groups at a specific epoxy equivalent of the entire component (A). Therefore, it is thought that the shape of the graph of the relational expression between the epoxy group consumption rate Y, which can reduce the decrease in adhesive strength, and the epoxy equivalent X of the entire component (A), will not be downwardly convex.
Furthermore, when the epoxy equivalent of the entire component (A) is in the region where it is less than 184 g/eq., this means that as the amount of low molecular weight epoxy resin in component (A) increases, a large amount of high molecular weight compounds and a dense crosslinked structure can be obtained with a small amount of reaction. However, even if a small amount of low molecular weight epoxy resin reacts, high molecular weight compounds are unlikely to be formed, and even if a high density crosslinked compound is formed, it is only in an extremely small region and is localized, so it is unlikely to significantly deteriorate the adhesive strength. Rather, it is thought that an increase in the proportion of low molecular weight compounds increases the consumption rate Y of epoxy groups, which affects the adhesive strength.
Furthermore, when the epoxy equivalent of the entire component (A) exceeds 410 g/eq., the allowable epoxy group consumption rate Y becomes 0% when the epoxy equivalent is 650 g/eq., and the formula (2) does not take into account cases above that. Furthermore, it is difficult to imagine that a specific component (A) epoxy equivalent in the range of 410 g/eq. to 650 g/eq. will result in a downwardly convex relationship.
From the above, it is believed that it is possible to sufficiently reduce the decrease in adhesive strength at least in the region below the proportional line connecting Examples 5 and 11.

The epoxy resin composition of the present invention has industrial applicability in applications such as interlayer insulating films, film-type solder resists, die attach films, encapsulating sheets, adhesive sheets, conductive films, anisotropically conductive films, and thermally conductive films. It also has industrial applicability in applications using these compositions for semiconductor elements, flexible substrates, printed wiring boards, power semiconductors, solar panels, and electronic components formed by combining one or more components selected from these groups.

Claims (9)

Component (A): an epoxy resin;
Component (B): a polymer different from the component (A),
Component (C): a heat curing agent;
A film having a support and an epoxy resin composition layer made of an epoxy resin composition, comprising:
When stored for 7 days under a temperature condition of 40 °C, the consumption rate Y (%) of epoxy groups during the storage period is 0% or more and 30% or less,
The component (A) epoxy resin has an epoxy equivalent X (g/eq.) of the entire component (A) epoxy resin, represented by the following formula (1), of 140 or more and 500 or less,
The consumption rate Y (%) of the epoxy group;
The epoxy equivalent X (g/eq.) of the entire epoxy resin of component (A), represented by the following formula (1), is
Satisfies the following formula (2):
A film having an epoxy resin composition layer and a support.
Epoxy equivalent weight X of all epoxy resins in component (A) = total mass of epoxy resins ÷ Σ (mass of each epoxy resin / each epoxy equivalent) ... Equation (1)
Y (%) ≦−0.06×X (g/eq.)+39 Formula (2) Component (A): an epoxy resin;
Component (B): a polymer different from the component (A),
Component (C): a heat curing agent;
A film having a support and an epoxy resin composition layer made of an epoxy resin composition, comprising :
when stored for 7 days under a temperature condition of 40°C, the consumption rate Y (%) of epoxy groups during the storage period is 0% or more and 30% or less,
the component (C): heat curing agent contains (C-1): microcapsule-type curing agent,
Component (D): Further containing a monofunctional epoxy compound having an aromatic ring,
A film having an epoxy resin composition layer and a support. Component (A): an epoxy resin;
Component (B): a polymer different from the component (A),
Component (C): a heat curing agent;
A film having a support and an epoxy resin composition layer made of an epoxy resin composition, comprising :
when stored for 7 days under a temperature condition of 40°C, the consumption rate Y (%) of epoxy groups during the storage period is 0% or more and 30% or less,
The component (C): a heat curing agent,
(C-2): at least one selected from the group consisting of an active ester curing agent and (C-3): dicyandiamide;
A film having an epoxy resin composition layer and a support. The component (A) epoxy resin is
The epoxy equivalent (g/eq.) of the entire epoxy resin of component (A), represented by the following formula (1), is 140 or more and 500 or less:
A film having a layer of the epoxy resin composition according to claim 2 or 3 and a support.
Epoxy equivalent of all epoxy resins in component (A) = total mass of epoxy resins ÷ Σ (mass of each epoxy resin / each epoxy equivalent) ... Equation (1) a protective layer on the surface of the epoxy resin composition layer opposite to the support;
A film comprising a layer of the epoxy resin composition according to any one of claims 1 to 4 and a support. any one selected from the group consisting of an interlayer insulating film, a film-type solder resist, a die attach film, a sealing sheet, an adhesive sheet, a conductive film, an anisotropic conductive film, and a thermally conductive film;
A film comprising a layer of the epoxy resin composition according to any one of claims 1 to 5 and a support. A cured product of the epoxy resin composition layer constituting a film having the epoxy resin composition layer according to any one of claims 1 to 6 and a support. A metal substrate;
The cured product according to claim 7 ,
A structure having: An electronic component comprising the cured product according to claim 7 in combination with one or more selected from the group consisting of a semiconductor element, a flexible substrate, a printed wiring board, a power semiconductor, and a solar panel.