JP7619080B2 - Epoxy resin, epoxy resin composition, cured product thereof, and laminate - Google Patents

Description

The present invention relates to an epoxy resin having a specific structure. It also relates to a composition containing two types of epoxy resins and a cured product obtained by curing the composition. It also relates to a laminate having a layer made of the cured product.

The weight of automobiles and airplanes is becoming increasingly lighter due to the need to reduce _CO2 emissions and improve fuel efficiency, and this has led to weight reductions through the reduction of the number of spot welds and the combined use of fiber-reinforced resin and metal, and there is a strong demand for high-performance adhesives for structural materials used in these applications. In particular, in the heat bonding of aluminum and fiber-reinforced resin, which have a large difference in thermal expansion, the occurrence of warping and waving due to interface stress accompanying expansion and contraction is a problem, and adhesives that can relieve stress are required.
Additionally, for advanced electronic materials used in applications such as semiconductor encapsulation and insulating layers for multilayer printed circuit boards, warping caused by the difference in thermal expansion between silicon chips and metals has become a serious issue as these materials become increasingly thin, creating greater demand for stress relief functions.

On the other hand, epoxy resins are widely used as adhesives because they have dimensional stability when cured, electrical insulation, and chemical resistance. However, when trying to maintain high adhesiveness, they become brittle, so flexible epoxy resins have been disclosed, such as high molecular weight epoxy resins made by reacting liquid bisphenol A type epoxy resins with aliphatic dicarboxylic acids such as dimer acid and sebacic acid as a molecular chain extender (see, for example, Patent Document 1), and high molecular weight epoxy resins derived from hydroxy compounds having aliphatic hydrocarbon groups (see Patent Document 2). However, flexible epoxy resins have a plastic deformation mode, so they cannot repeatedly follow the expansion difference of the base material while maintaining the overall rigidity, and there are problems with durability.

Epoxy resins that exhibit high elongation accompanied by elastic deformation generally have low glass transition temperatures, and while they have excellent flexibility and adhesive properties near the glass transition temperature, their adhesive strength drops significantly at high temperatures above the glass transition temperature. On the other hand, epoxy resins with high glass transition temperatures have low temperature dependence of adhesive strength, but they have poor flexibility and no stress relaxation function. For these reasons, there is a demand for epoxy resins that give flexible cured products that combine high elongation that requires elastic deformation with adhesive properties at room temperature and high temperatures.

Japanese Patent Application Publication No. 8-53533 JP 2006-335796 A

The object of the present invention is to provide a resin composition that gives a flexible cured product that has both flexibility resistant to temperature changes and deformation and high adhesiveness that can withstand the thermal expansion difference of the substrate, and a new epoxy resin that can be suitably used with the composition. It is also to provide a cured product obtained by curing the resin composition, and a laminate characterized by having a layer made of the cured product and a substrate.

After extensive research, the inventors have found that the above problems can be solved by using an epoxy resin having a specific structure. That is, the present invention relates to an epoxy resin having the following general formula (1):

〔式（１）中、Ａｒはそれぞれ独立して、無置換又は置換基を有する芳香環を有する構造であり、
Ｘは下記一般式（２）で表される構造単位であり、Ｙは下記一般式（３）で表される構造単位であり、

[In formula (1), each Ar is independently a structure having an unsubstituted or substituted aromatic ring,
X is a structural unit represented by the following general formula (2), and Y is a structural unit represented by the following general formula (3):

［式（２）、（３）中、Ａｒは前記と同じであり、
Ｒ_１、Ｒ_２はそれぞれ独立して水素原子、メチル基又はエチル基であり、
Ｒ’は炭素原子数２～１２の２価の炭化水素基であり、
Ｒ_３、Ｒ_４、Ｒ_７、Ｒ_８はそれぞれ独立して水酸基、グリシジルエーテル基又は２－メチルグリシジルエーテル基であり、
Ｒ_５、Ｒ_６、Ｒ_９、Ｒ_１０はそれぞれ独立して水素原子又はメチル基であり、
ｎ１は４～１６の整数であり、
ｎ２は繰り返し単位の平均値で２～３０である。］
Ｒ_１１、Ｒ_１２はそれぞれ独立して、グリシジルエーテル基又は２－メチルグリシジルエーテル基であり、
Ｒ_１３、Ｒ_１４はそれぞれ独立して水酸基、グリシジルエーテル基又は２－メチルグリシジルエーテル基であり、
Ｒ_１５、Ｒ_１６は水素原子又はメチル基であり、
ｐ１、ｐ２、ｑは繰り返しの平均値であって、
ｐ１、ｐ２はそれぞれ独立して０～５であり、
ｑは０．５～５である。ただし、前記一般式（２）で表されるＸと前記一般式（３）で表されるＹとの結合は、ランダムであってもブロックであってもよく、１分子中に存在する各構造単位Ｘ、Ｙの数の総数がそれぞれｍ１、ｍ２であることを示す。〕
で表されるエポキシ樹脂であって、
１≦ｍ１≦２５且つ１≦ｍ２≦２５のエポキシ樹脂（ａ１）、又は、
１≦ｍ１≦２５且つｍ２＝０のエポキシ樹脂（ａ２）と、ｍ１＝０且つ１≦ｍ２≦２５のエポキシ樹脂（ａ３）とを必須成分とする、エポキシ当量が５００～１０，０００ｇ／ｅｑのエポキシ樹脂（Ａ）と、
エポキシ当量が１００～３００ｇ／ｅｑのエポキシ樹脂（Ｂ）と、
を含有することを特徴とするエポキシ樹脂組成物を提供するものである。

[In the formulas (2) and (3), Ar is the same as defined above,
R ₁ and R ₂ each independently represent a hydrogen atom, a methyl group, or an ethyl group;
R' is a divalent hydrocarbon group having 2 to 12 carbon atoms;
R ₃ , R ₄ , R ₇ and R ₈ each independently represent a hydroxyl group, a glycidyl ether group or a 2-methylglycidyl ether group;
R ₅ , R ₆ , R ₉ , and R ₁₀ each independently represent a hydrogen atom or a methyl group;
n1 is an integer from 4 to 16,
n2 is the average number of repeating units and is from 2 to 30.
R ₁₁ and R ₁₂ each independently represent a glycidyl ether group or a 2-methylglycidyl ether group;
R ₁₃ and R ₁₄ each independently represent a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group;
R ₁₅ and R ₁₆ each represent a hydrogen atom or a methyl group;
p1, p2, and q are the average values of the repetitions,
p1 and p2 each independently represent 0 to 5;
and q is 0.5 to 5. However, the bond between X represented by the general formula (2) and Y represented by the general formula (3) may be random or block, and the total numbers of the structural units X and Y present in one molecule are m1 and m2, respectively.
An epoxy resin represented by the formula:
Epoxy resin (a1) in which 1≦m1≦25 and 1≦m2≦25; or
An epoxy resin (A) having an epoxy equivalent of 500 to 10,000 g/eq, comprising, as essential components, an epoxy resin (a2) satisfying 1≦m1≦25 and m2=0, and an epoxy resin (a3) satisfying m1=0 and 1≦m2≦25;
An epoxy resin (B) having an epoxy equivalent of 100 to 300 g/eq;
The present invention provides an epoxy resin composition comprising:

The present invention also provides a cured product of the epoxy resin composition, and a laminate having a layer made of the cured product.

Furthermore, the present invention relates to a compound represented by the following general formula (5):

〔式（５）中、Ａｒはそれぞれ独立して、無置換又は置換基を有する芳香環を有する構造であり、
Ｘは下記一般式（２）で表される構造単位であり、Ｙは下記一般式（３）で表される構造単位であり、

In formula (5), each Ar is independently a structure having an unsubstituted or substituted aromatic ring,
X is a structural unit represented by the following general formula (2), and Y is a structural unit represented by the following general formula (3):

［式（２）、（３）中、Ａｒは前記と同じであり、
Ｒ_１、Ｒ_２はそれぞれ独立して水素原子、メチル基又はエチル基であり、
Ｒ’は炭素原子数２～１２の２価の炭化水素基であり、
Ｒ_３、Ｒ_４、Ｒ_７、Ｒ_８はそれぞれ独立して水酸基、グリシジルエーテル基又は２－メチルグリシジルエーテル基であり、
Ｒ_５、Ｒ_６、Ｒ_９、Ｒ_１０はそれぞれ独立して水素原子又はメチル基であり、
ｎ１は４～１６の整数であり、
ｎ２は繰り返し単位の平均値で２～３０である。］
Ｒ_１１、Ｒ_１２はそれぞれ独立して、グリシジルエーテル基又は２－メチルグリシジルエーテル基であり、
Ｒ_１３、Ｒ_１４はそれぞれ独立して水酸基、グリシジルエーテル基又は２－メチルグリシジルエーテル基であり、
Ｒ_１５、Ｒ_１６は水素原子又はメチル基であり、
ｐ１、ｐ２、ｑは繰り返しの平均値であって、
ｐ１、ｐ２はそれぞれ独立して０～５であり、
ｑは０．５～５である。ただし、前記一般式（２）で表されるＸと前記一般式（３）で表されるＹとの結合は、ランダムであってもブロックであってもよく、１分子中に存在する各構造単位Ｘ、Ｙの数の総数がそれぞれｍ１、ｍ２であることを示す。〕
で表されるエポキシ樹脂であって、
１≦ｍ１≦２５且つ１≦ｍ２≦２５であり、エポキシ当量が５００～１０，０００ｇ／ｅｑであることを特徴とするエポキシ樹脂を提供するものである。

[In the formulas (2) and (3), Ar is the same as defined above,
R ₁ and R ₂ each independently represent a hydrogen atom, a methyl group, or an ethyl group;
R' is a divalent hydrocarbon group having 2 to 12 carbon atoms;
R ₃ , R ₄ , R ₇ and R ₈ each independently represent a hydroxyl group, a glycidyl ether group or a 2-methylglycidyl ether group;
R ₅ , R ₆ , R ₉ , and R ₁₀ each independently represent a hydrogen atom or a methyl group;
n1 is an integer from 4 to 16,
n2 is the average number of repeating units and is from 2 to 30.
R ₁₁ and R ₁₂ each independently represent a glycidyl ether group or a 2-methylglycidyl ether group;
R ₁₃ and R ₁₄ each independently represent a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group;
R ₁₅ and R ₁₆ each represent a hydrogen atom or a methyl group;
p1, p2, and q are the average values of the repetitions,
p1 and p2 each independently represent 0 to 5;
and q is 0.5 to 5. However, the bond between X represented by the general formula (2) and Y represented by the general formula (3) may be random or block, and the total numbers of the structural units X and Y present in one molecule are m1 and m2, respectively.
An epoxy resin represented by the formula:
The epoxy resin is characterized in that 1≦m1≦25 and 1≦m2≦25, and has an epoxy equivalent of 500 to 10,000 g/eq.

The epoxy resin of the present invention has a long-chain alkylene chain and a polyether chain, and therefore can provide a flexible cured product that has both high elongation assuming elastic deformation and high adhesion that can withstand the thermal expansion difference of the substrate. In addition, the composition of the present invention can provide a cured product having a phase separation structure that has both adhesion and stress relaxation ability in the cured product and can exhibit high adhesion over a wide temperature range.

The present invention relates to a compound represented by the following general formula (1):

〔式（１）中、Ａｒはそれぞれ独立して、無置換又は置換基を有する芳香環を有する構造であり、
Ｘは下記一般式（２）で表される構造単位であり、Ｙは下記一般式（３）で表される構造単位であり、

[In formula (1), each Ar is independently a structure having an unsubstituted or substituted aromatic ring,
X is a structural unit represented by the following general formula (2), and Y is a structural unit represented by the following general formula (3):

［式（２）、（３）中、Ａｒは前記と同じであり、
Ｒ_１、Ｒ_２はそれぞれ独立して水素原子、メチル基又はエチル基であり、
Ｒ’は炭素原子数２～１２の２価の炭化水素基であり、
Ｒ_３、Ｒ_４、Ｒ_７、Ｒ_８はそれぞれ独立して水酸基、グリシジルエーテル基又は２－メチルグリシジルエーテル基であり、
Ｒ_５、Ｒ_６、Ｒ_９、Ｒ_１０はそれぞれ独立して水素原子又はメチル基であり、
ｎ１は４～１６の整数であり、
ｎ２は繰り返し単位の平均値で２～３０である。］
Ｒ_１１、Ｒ_１２はそれぞれ独立して、グリシジルエーテル基又は２－メチルグリシジルエーテル基であり、
Ｒ_１３、Ｒ_１４はそれぞれ独立して水酸基、グリシジルエーテル基又は２－メチルグリシジルエーテル基であり、
Ｒ_１５、Ｒ_１６は水素原子又はメチル基であり、
ｐ１、ｐ２、ｑは繰り返しの平均値であって、
ｐ１、ｐ２はそれぞれ独立して０～５であり、
ｑは０．５～５である。ただし、前記一般式（２）で表されるＸと前記一般式（３）で表されるＹとの結合は、ランダムであってもブロックであってもよく、１分子中に存在する各構造単位Ｘ、Ｙの数の総数がそれぞれｍ１、ｍ２であることを示す。〕
で表されるエポキシ樹脂であって、
１≦ｍ１≦２５且つ１≦ｍ２≦２５のエポキシ樹脂（ａ１）、又は、
１≦ｍ１≦２５且つｍ２＝０のエポキシ樹脂（ａ２）と、ｍ１＝０且つ１≦ｍ２≦２５のエポキシ樹脂（ａ３）とを必須成分とする、エポキシ当量が５００～１０，０００ｇ／ｅｑのエポキシ樹脂（Ａ）と、
エポキシ当量が１００～３００ｇ／ｅｑのエポキシ樹脂（Ｂ）と、
を含有することを特徴とするエポキシ樹脂組成物である。

[In the formulas (2) and (3), Ar is the same as defined above,
R ₁ and R ₂ each independently represent a hydrogen atom, a methyl group, or an ethyl group;
R' is a divalent hydrocarbon group having 2 to 12 carbon atoms;
R ₃ , R ₄ , R ₇ and R ₈ each independently represent a hydroxyl group, a glycidyl ether group or a 2-methylglycidyl ether group;
R ₅ , R ₆ , R ₉ , and R ₁₀ each independently represent a hydrogen atom or a methyl group;
n1 is an integer from 4 to 16,
n2 is the average number of repeating units and is from 2 to 30.
R ₁₁ and R ₁₂ each independently represent a glycidyl ether group or a 2-methylglycidyl ether group;
R ₁₃ and R ₁₄ each independently represent a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group;
R ₁₅ and R ₁₆ each represent a hydrogen atom or a methyl group;
p1, p2, and q are the average values of the repetitions,
p1 and p2 each independently represent 0 to 5;
and q is 0.5 to 5. However, the bond between X represented by the general formula (2) and Y represented by the general formula (3) may be random or block, and the total numbers of the structural units X and Y present in one molecule are m1 and m2, respectively.
An epoxy resin represented by the formula:
Epoxy resin (a1) in which 1≦m1≦25 and 1≦m2≦25; or
An epoxy resin (A) having an epoxy equivalent of 500 to 10,000 g/eq, comprising, as essential components, an epoxy resin (a2) satisfying 1≦m1≦25 and m2=0, and an epoxy resin (a3) satisfying m1=0 and 1≦m2≦25;
An epoxy resin (B) having an epoxy equivalent of 100 to 300 g/eq;
The epoxy resin composition is characterized by comprising:

<Epoxy resin (A)>
The epoxy resin (A) used in the present invention is characterized in that it essentially comprises an epoxy resin (a1) having a structural unit X represented by the formula (2) and a structural unit Y represented by the formula (3) and has an epoxy equivalent of 500 to 10,000 g/eq, or in that it uses an epoxy resin (a2) having a structural unit X represented by the formula (2) in combination with an epoxy resin (a3) having a structural unit (Y) represented by the formula (3), and the epoxy equivalent of the mixture of them is 500 to 10,000 g/eq. In this case, in the epoxy resin (a1), the bonding form between the structural unit X and the structural unit Y is not particularly limited and may be random or block, and the total number of each structural unit present in one molecule is m1 and m2, respectively.

In the present invention, by using an epoxy resin (A) having such a specific structure, the cured product contains a structure derived from the long-chain alkylene chain of the structural unit X, and therefore has flexibility and can follow the thermal expansion difference of the substrate. In addition, since the epoxy resin composition contains a structure derived from the polyether chain in the structural unit Y, the viscosity of the epoxy resin (A) is kept low, improving workability in coating and molding, etc.

Hereinafter, the exemplified structures and preferred structures of the common moieties in the epoxy resins (a1), (a2), and (a3) will not be distinguished from one another because they are the same.
In the general formula (1), (2), and (3), Ar each independently represents a structure having an aromatic ring that is unsubstituted or has a substituent. The aromatic ring referred to here includes, for example, a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, and a fluorene ring. The structure having these aromatic rings, Ar, preferably represents a structure represented by the following formula (4).

・・・（４）

...(4)

In formula (4), the aromatic ring may be substituted or unsubstituted, and * represents the point of attachment.

In addition, in the general formulas (1), (2), and (3), structures represented by the following formulas are also included as Ar.

In this formula, the aromatic ring may be substituted or unsubstituted, n = 1 to 4, and * represents the point of attachment.

The aromatic ring of Ar may be substituted or unsubstituted. When Ar has a substituent, the substituent is preferably an alkyl group, a halogen atom, a glycidyl ether group, a 2-methylglycidyl ether group, or the like. It is preferably unsubstituted, or an alkyl group and a glycidyl ether group, or a 2-methylglycidyl ether group. The number of substituents per aromatic ring is preferably two or less, more preferably one or less, and particularly preferably unsubstituted.

The following structures are particularly preferred for Ar:

Particularly preferred structures for Ar having a substituent include the following structures:

In the structural unit X, the repeating unit _n1 is an integer of 4 to 16. When _n1 is 4 or more, the adhesive strength is improved and the deformation mode of the cured product is elastic deformation. When _n1 is 16 or less, a decrease in crosslink density can be suppressed. It is preferably 4 to 12, and more preferably 6 to 12.

In the structural unit X, R ₁ and R ₂ each independently represent a hydrogen atom, a methyl group, or an ethyl group, R ₃ and R ₄ each independently represent a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R ₅ and R ₆ each independently represent a hydrogen atom or a methyl group. Of these, R ₃ and R ₄ are preferably hydroxyl groups, and R ₅ and R ₆ are preferably hydrogen atoms.

In the structural unit Y, the repeating unit _n2 has an average value of 2 to 30. This range is preferable in terms of a good balance between resin viscosity and crosslink density. It is preferably 2 to 25, and more preferably 4 to 20.

In the structural unit Y, R' represents a divalent hydrocarbon group having 2 to 12 carbon atoms. Within this range, the adhesive strength is improved and the deformation mode of the cured product is elastic. Preferably, R' is a divalent hydrocarbon group having 2 to 6 carbon atoms.

Examples of the divalent hydrocarbon group include linear or branched alkylene groups, alkenylene groups, alkynylene groups, cycloalkylene groups, arylene groups, and aralkylene groups (divalent groups having an alkylene group and an arylene group).

Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group.
Examples of the alkenylene group include a vinylene group, a 1-methylvinylene group, a propenylene group, a butenylene group, and a pentenylene group.
Examples of the alkynylene group include an ethynylene group, a propynylene group, a butynylene group, a pentynylene group, and a hexynylene group.
Examples of the cycloalkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, and a cyclohexylene group.
Examples of the arylene group include a phenylene group, a tolylene group, a xylylene group, and a naphthylene group.

Among these, ethylene groups, propylene groups, and tetramethylene groups are preferred from the viewpoint of the balance between the ease of raw material availability, the viscosity of the resulting epoxy resin (A), and the flexibility of the cured product.

In the structural unit Y, R ₇ and R ₈ each independently represent a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R ₉ and R ₁₀ each independently represent a hydrogen atom or a methyl group. Among these, R ₇ and R ₈ are preferably hydroxyl groups, and R ₉ and R ₁₀ are preferably hydrogen atoms.

In addition, R ₁₁ and R ₁₂ in the general formula (1) are each independently a glycidyl ether group or a 2-methylglycidyl ether group, R ₁₃ and R ₁₄ are each independently a hydroxyl group, a glycidyl ether group or a 2-methylglycidyl ether group, R ₁₅ and R ₁₆ are a hydrogen atom or a methyl group, p1, p2 and q are average values of repetition, p1 and p2 are each independently 0 to 5, and q is 0.5 to 5. Among these, it is preferable that R ₁₁ and R ₁₂ are a glycidyl ether group, R ₁₃ and R ₁₄ are preferably a hydroxyl group, and R ₁₅ and R ₁₆ are preferably a hydrogen atom. It is also preferable that p1 and p2 are 0 to 2, and q is preferably 0.5 to 2.

Furthermore, the epoxy equivalent of the epoxy resin (A) used in the present invention is 500 to 10,000 g/eq. This range ensures an excellent balance between flexibility and crosslink density of the resulting cured product. From the standpoint of ease of handling and a better balance between flexibility and crosslink density, the range of 600 to 8,000 g/eq is preferred, and the range of 800 to 5000 g/eq is even more preferred.

The epoxy resin (a1) of the present invention may, for example, have the following structure:

In the structural formulas (A-1) to (A-12), ran represents a random bond, G represents a glycidyl group, R' represents a divalent hydrocarbon group having 2 to 12 carbon atoms, _n1 represents an integer of 4 to 16, _n2 represents the average value of the repeating units and is 2 to 30, p1, p2, and q represent the average value of the repeating units, p1 and p2 are each independently 0 to 5, q is 0.5 to 5, and 1≦m1≦25 and 1≦m2≦25. However, each repeating unit present in the repeating unit may be the same or different.

Among the above structural formulas, it is most preferable to use those represented by the structural formulas (A-1), (A-2), (A-3), (A-5), (A-7), (A-8), and (A-9) in view of obtaining a better balance of physical properties of the cured product.

Among the epoxy resins (A), examples of the epoxy resins (a2) having the structural unit X include resins represented by the following structural formula:

In each of the structural formulas (A-13) to (A-24), G is a glycidyl group, _n1 is an integer of 4 to 16, p1, p2, and q are average values of the repeating units, p1 and p2 are each independently 0 to 5, q is 0.5 to 5, and 1≦m1≦25. However, each repeating unit present in the repeating unit may be the same or different.

Among the above structural formulas, those represented by structural formulas (A-13), (A-14), (A-15), (A-17), (A-19), (A-20), and (A-21) are preferred because they provide a better balance of physical properties in the resulting cured product.

Among the epoxy resins (A), examples of the epoxy resins (a3) having the structural unit Y include resins represented by the following structural formula:

In each of the structural formulas (A-25) to (A-36), G is a glycidyl group, R' is a divalent hydrocarbon group having 2 to 12 carbon atoms, _n2 is the average value of the repeating units and is 2 to 30, p1, p2, and q are the average values of the repeating units and are 1≦m2≦25, p1 and p2 are each independently 0 to 5, and q is 0.5 to 5. However, each repeating unit present in the repeating unit may be the same or different.

Among the above structural formulas, it is most preferable to use those represented by the structural formulas (A-25), (A-26), (A-27), (A-29), (A-31), (A-32), and (A-33) because they provide a better balance of physical properties of the resulting cured product.

The method for producing the epoxy resin (A) used in the present invention is not particularly limited, but for example, a method in which a diglycidyl ether (x1) of a dihydroxy compound having an alkylene chain or a polyether chain is reacted with an aromatic hydroxy compound (x2) in a molar ratio (x1)/(x2) of 1/1.01 to 1/5.0 to obtain a hydroxy compound [corresponding to a precursor or intermediate of the epoxy resin (A)], and then reacted with epihalohydrin (x3) is preferable in terms of ease of obtaining raw materials and reaction. In this case, when the diglycidyl ether of the dihydroxy compound having an alkylene chain is used alone, the epoxy resin (a2) can be obtained, when the diglycidyl ether of the dihydroxy compound having a polyether chain is used alone, the epoxy resin (a3) can be obtained, and when the diglycidyl ether of the dihydroxy compound having an alkylene chain and the diglycidyl ether of the dihydroxy compound having a polyether chain are used in combination, the epoxy resin (a1) can be obtained.

The epoxy resin (a1) can also be obtained by reacting the epoxy resin (a2) and the epoxy resin (a3) obtained above with an aromatic hydroxy compound (x2) as raw materials.

The product obtained by the reaction of the diglycidyl ether (x1) of a dihydroxy compound having an alkylene chain or a polyether chain with an aromatic hydroxy compound (x2) to obtain a hydroxy compound may contain unreacted aromatic hydroxy compound (x2). In the synthesis of the epoxy resin (A) used in the present invention, the product may be directly subjected to the reaction with epihalohydrin (x3), which is the next step, or the unreacted aromatic hydroxy compound (x2) may be removed. However, from the viewpoint of the balance between the toughness and flexibility of the cured product obtained from the epoxy resin composition of the present invention containing the resulting epoxy resin (A), the presence rate of the unreacted aromatic hydroxy compound (x2) in the hydroxy compound to be subjected to the next step is preferably in the range of 0.1 to 30% on a mass basis.

The method for removing the unreacted aromatic hydroxy compound (x2) is not particularly limited, and can be carried out in accordance with various methods. For example, column chromatography separation method utilizing the difference in polarity, distillation fractional distillation utilizing the difference in boiling point, alkaline aqueous extraction method utilizing the difference in solubility in alkaline water, etc. can be mentioned. Among them, alkaline aqueous extraction method is preferable in terms of efficiency, etc., because it does not involve thermal deterioration. In this case, as the organic solvent used to dissolve the target substance, any organic solvent that is not miscible with water, such as toluene or methyl isobutyl ketone, can be used, but it is particularly preferable to use methyl isobutyl ketone from the viewpoint of solubility with the target substance.

The diglycidyl ether (x1) of a dihydroxy compound having an alkylene chain or a polyether chain is not particularly limited. For example, examples of diglycidyl ethers having an alkylene chain include 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,9-nonanediol diglycidyl ether, 1,11-undecanediol diglycidyl ether, 1,12-dodecanediol diglycidyl ether, 1,13-tridecanediol diglycidyl ether, 1,14-tetradecanediol diglycidyl ether, 1,15-pentadecanediol diglycidyl ether, 1,16-hexadecanediol diglycidyl ether, 2-methyl-1,11-undecanediol diglycidyl ether, 3-methyl-1,11-undecanediol diglycidyl ether, and 2,6,10-trimethyl-1,11-undecanediol diglycidyl ether. Examples of diglycidyl ethers having a polyether chain include polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, polypentamethylene glycol diglycidyl ether, polyhexamethylene glycol diglycidyl ether, and polyheptamethylene glycol diglycidyl ether. These may contain organic chlorine impurities generated during the glycidyl etherification of hydroxy compounds, and may contain organic chlorine such as 1-chloromethyl-2-glycidyl ether (chloromethyl form) represented by the following structure. These diglycidyl ethers may be used alone or in combination of two or more types.

Among these, it is preferable to use 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,9-nonanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and polytetramethylene glycol diglycidyl ether, because they provide an excellent balance between flexibility and heat resistance in the resulting cured product.

In addition, by simultaneously reacting the diglycidyl ether having an alkylene chain and the diglycidyl ether having a polyether chain with an aromatic hydroxy compound (x2), a hydroxy compound having both structural units X and Y can be obtained, and by further reacting this with epihalohydrin (x3), an epoxy resin (A) having both structural units X and Y can be obtained.

The aromatic hydroxy compound (x2) is not particularly limited, and examples thereof include dihydroxybenzenes such as hydroquinone, resorcin, and catechol, trihydroxybenzenes such as pyrogallol, 1,2,4-trihydroxybenzene, and 1,3,5-trihydroxybenzene, triphenylmethane-type phenols such as 4,4',4"-trihydroxytriphenylmethane, 1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene. dihydroxynaphthalenes such as 1,1'-methylenebis-(2,7-naphthalenediol), 1,1'-binaphthalene-2,2',7,7'-tetraol, 1,1'-oxybis-(2,7-naphthalenediol) and other tetrafunctional phenols obtained by coupling reaction of dihydroxynaphthalenes; bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, and 1,1-bis(4-hydroxyphenyl)cyclohexane. bisphenols such as bis(4-hydroxyphenyl)sulfone, 2,2'-biphenol, 4,4'-biphenol, (1,1'-biphenyl)-3,4-diol, 3,3'-dimethyl-(1,1'-biphenyl)-4,4'-diol, 3-methyl-(1,1'-biphenyl)-4,4'-diol, 3,3',5,5'-tetramethylbiphenyl-2,2'-diol, 3,3',5,5'-tetramethylbiphenyl-4,4'-diol, 5-methyl-(1,1'-biphenyl)-3,4'diol, 3'-methyl-(1,1'- Examples of such phenols include biphenols such as 4'-methyl-(1,1'-biphenyl)-3,4'diol and 4'-methyl-(1,1'-biphenyl)-3,4'diol, alicyclic structure-containing phenols such as polyaddition products of phenol and dicyclopentadiene and polyaddition products of phenol and terpene compounds, naphthols such as bis(2-hydroxy-1-naphthyl)methane and bis(2-hydroxy-1-naphthyl)propane, and so-called Xylok-type phenolic resins which are condensation reaction products of phenol and phenylene dimethyl chloride or biphenylene dimethyl chloride. These may be used alone or in combination of two or more. Further examples include compounds having a structure in which a methyl group, a t-butyl group, or a halogen atom is substituted as a substituent on the aromatic nucleus of each of the above compounds. In addition, the alicyclic structure-containing phenols and the Zylok-type phenolic resins may contain not only bifunctional components but also trifunctional or higher functional components at the same time. In the present invention, they may be used as they are, or they may be purified using a column or other purification process to extract only the bifunctional components.

Among these, bisphenols are preferred because they provide an excellent balance between flexibility and toughness when cured, and bis(4-hydroxyphenyl)methane and 2,2-bis(4-hydroxyphenyl)propane are particularly preferred because of their outstanding toughness-imparting properties. If the curing properties and heat resistance of the cured product are important, dihydroxynaphthalenes are preferred, and 2,7-dihydroxynaphthalene is particularly preferred because of its outstanding fast-curing properties. If the moisture resistance of the cured product is important, it is preferable to use a compound containing an alicyclic structure.

From the viewpoint of reaction efficiency, the reaction ratio of the diglycidyl ether (x1) of the dihydroxy compound having an alkylene chain or polyether chain and the aromatic hydroxy compound (x2) is preferably (x1)/(x2) from 1/1.01 to 1/5.0 (molar ratio), and more preferably (x1)/(x2) from 1/1.02 to 1/3.0 (molar ratio).

The reaction of the diglycidyl ether (x1) of a dihydroxy compound having an alkylene chain or a polyether chain with the aromatic hydroxy compound (x2) is preferably carried out in the presence of a catalyst. As the catalyst, various catalysts can be used, for example, alkali (earth) metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, etc., alkali metal carbonates such as sodium carbonate, potassium carbonate, etc., phosphorus compounds such as triphenylphosphine, etc., chlorides such as DMP-30, DMAP, tetramethylammonium, tetraethylammonium, tetrabutylammonium, benzyltributylammonium, bromides, iodides, quaternary ammonium salts such as chlorides such as tetramethylphosphonium, tetraethylphosphonium, tetrabutylphosphonium, benzyltributylphosphonium, bromides, iodides, etc., tertiary amines such as triethylamine, N,N-dimethylbenzylamine, 1,8-diazabicyclo[5.4.0]undecene, 1,4-diazabicyclo[2.2.2]octane, etc., imidazoles such as 2-ethyl-4-methylimidazole, 2-phenylimidazole, etc., etc. Two or more of these catalysts may be used in combination. Among these, sodium hydroxide, potassium hydroxide, triphenylphosphine, and DMP-30 are preferred because the reaction proceeds quickly and the effect of reducing the amount of impurities is high. The amount of these catalysts used is not particularly limited, but it is preferable to use 0.0001 to 0.1 moles per mole of aromatic hydroxyl group in the aromatic hydroxy compound (x2). The form of these catalysts is also not particularly limited, and they may be used in the form of an aqueous solution or in the form of a solid.

The reaction between the diglycidyl ether (x1) of the dihydroxy compound having an alkylene chain or a polyether chain and the aromatic hydroxy compound (x2) can be carried out without a solvent or in the presence of an organic solvent. Examples of organic solvents that can be used include methyl cellosolve, ethyl cellosolve, toluene, xylene, methyl isobutyl ketone, dimethyl sulfoxide, propyl alcohol, and butyl alcohol. The amount of the organic solvent used is usually 50 to 300% by mass, preferably 100 to 250% by mass, based on the total mass of the raw materials charged. These organic solvents can be used alone or in combination. In order to carry out the reaction quickly, it is preferable to use no solvent, while it is preferable to use dimethyl sulfoxide in order to reduce impurities in the final product.

The reaction temperature for the reaction is usually 50 to 180°C, and the reaction time is usually 1 to 30 hours. The reaction temperature is preferably 100 to 160°C in order to reduce impurities in the final product. If the resulting compound is significantly colored, an antioxidant or reducing agent may be added to suppress this. The antioxidant is not particularly limited, but examples thereof include hindered phenol compounds such as 2,6-dialkylphenol derivatives, divalent sulfur compounds, and phosphite ester compounds containing a trivalent phosphorus atom. The reducing agent is not particularly limited, but examples thereof include hypophosphorous acid, phosphorous acid, thiosulfuric acid, sulfurous acid, hydrosulfite, or salts thereof.

After the reaction is completed, the reaction mixture may be neutralized or washed until its pH value reaches 3 to 7, preferably 5 to 7. The neutralization and washing may be carried out according to a conventional method. For example, when a basic catalyst is used, an acidic substance such as hydrochloric acid, sodium dihydrogen phosphate, p-toluenesulfonic acid, or oxalic acid may be used as a neutralizing agent. After neutralization or washing, the solvent may be distilled off under reduced pressure and heating, if necessary, to concentrate the product, thereby obtaining a hydroxy compound.

By using a glycidyl ether having an alkylene chain in combination with a glycidyl ether having a polyether chain, a hydroxy compound having both the structural unit X and the structural unit Y can be obtained. In this case, a preferred structure is, for example, a compound represented by the following structural formula.

In the above structural formulas, ran represents a random bond, R' represents a divalent hydrocarbon group having 2 to 12 carbon atoms, _n1 represents an integer from 4 to 16, _n2 represents the average value of the repeating units and is 2 to 30, and 1≦m1≦25 and 1≦m2≦25. However, each repeating unit present in the repeating unit may be the same or different.

In addition, a hydroxy compound having the structural unit X can be obtained by using the glycidyl ether having the alkylene chain as a raw material. In this case, a preferred structure is, for example, a compound represented by the following structural formula.

In each of the above structural formulas, _n1 is an integer of 4 to 16, and 1≦m1≦25.

In addition, a hydroxy compound having the structural unit Y can be obtained by using the glycidyl ether having the polyether chain as a raw material. In this case, a preferred structure is, for example, a compound represented by the following structural formula.

In each of the above structural formulas, R' is a divalent hydrocarbon group having 2 to 12 carbon atoms, _n2 is the average value of the repeating units and is 2 to 30, and 1≦m2≦25. However, each repeating unit present in the repeating unit may be the same or different.

In the method for producing the epoxy resin (A), the method for the glycidyl etherification reaction of the precursor (intermediate) hydroxy compound obtained above is not particularly limited, and examples thereof include a method of reacting a phenolic hydroxyl group with epihalohydrin, and a method of olefinizing the phenolic hydroxyl group and oxidizing the carbon-carbon double bond of the olefin with an oxidizing agent. Among these, the method using epihalohydrin (x3) is preferred in terms of ease of obtaining raw materials and reaction.

As a method using epihalohydrin (x3), for example, 0.3 to 100 moles of epihalohydrin (x3) are added per mole of aromatic hydroxyl group of the hydroxy compound obtained above, and the mixture is reacted at a temperature of 20 to 120°C for 0.5 to 10 hours while adding 0.9 to 2.0 moles of basic catalyst per mole of aromatic hydroxyl group of the hydroxy compound all at once or gradually. The amount of epihalohydrin (x3) added is such that the epoxy resin obtained is closer to the theoretical structure as the excess amount of epihalohydrin (x3) increases, and the generation of secondary hydroxyl groups resulting from the reaction of unreacted aromatic hydroxyl groups with epoxy groups can be suppressed. From this viewpoint, the range of 2.5 to 100 equivalents is preferable. The basic catalyst may be a solid or an aqueous solution thereof. When an aqueous solution is used, it may be added continuously, and water and epihalohydrin (x3) may be continuously distilled from the reaction mixture under reduced pressure or normal pressure, and then the water may be removed by liquid separation, while the epihalohydrin (x3) may be continuously returned to the reaction mixture.

In industrial production, all of the epihalohydrin (x3) charged is fresh in the first batch of epoxy resin production, but from the next batch onwards, it is preferable to use a combination of epihalohydrin (x3) recovered from the crude reaction product and fresh epihalohydrin (x3) equivalent to the amount consumed and lost in the reaction. At this time, the epihalohydrin (x3) used is not particularly limited, but examples include epichlorohydrin, epibromohydrin, etc. Among these, epichlorohydrin is preferred because it is easily available.

The basic catalyst is not particularly limited, but examples thereof include alkaline earth metal hydroxides, alkali metal carbonates, and alkali metal hydroxides. In particular, alkali metal hydroxides are preferred because of their excellent catalytic activity in the epoxy resin synthesis reaction, and examples of such hydroxides include sodium hydroxide and potassium hydroxide. When used, these alkali metal hydroxides may be used in the form of an aqueous solution of about 10 to 55 mass %, or in the form of a solid.

In addition, the reaction rate in the synthesis of the epoxy resin can be increased by using an organic solvent in combination. Such organic solvents are not particularly limited, but examples include ketones such as acetone and methyl ethyl ketone, alcohols such as methanol, ethanol, 1-propyl alcohol, isopropyl alcohol, 1-butanol, secondary butanol, and tertiary butanol, cellosolves such as methyl cellosolve and ethyl cellosolve, ethers such as tetrahydrofuran, 1,4-dioxane, 1,3-dioxane, and diethoxyethane, and aprotic polar solvents such as acetonitrile, dimethyl sulfoxide, and dimethylformamide. These organic solvents may be used alone, or two or more of them may be used in combination as appropriate to adjust the polarity.

After washing the reaction products of these glycidylation reactions with water, the unreacted epihalohydrin (x3) and the organic solvent used in combination are removed by distillation under heating and reduced pressure. Furthermore, in order to obtain an epoxy resin with even less hydrolyzable halogen, the obtained epoxy resin can be dissolved again in an organic solvent such as toluene, methyl isobutyl ketone, or methyl ethyl ketone, and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide can be added to carry out further reaction. At this time, a phase transfer catalyst such as a quaternary ammonium salt or crown ether can be present in order to improve the reaction rate.

When a phase transfer catalyst is used, the amount used is preferably in the range of 0.1 to 3.0% by mass based on the epoxy resin used. After the reaction is completed, the salt formed is removed by filtration, washing with water, etc., and the solvent, such as toluene or methyl isobutyl ketone, is distilled off under heating and reduced pressure to obtain a high-purity epoxy resin.

The blending ratio of the epoxy resin (a2) and the epoxy resin (a3) obtained above is not limited in any way other than that the epoxy equivalent of the mixture is in the range of 500 to 10,000 g/eq, and can be appropriately selected depending on the physical properties of the desired cured product. For example, the mass ratio of epoxy resin (a2)/epoxy resin (a3) is preferably in the range of 20/80 to 80/20, and more preferably in the range of 30/70 to 70/30.

In the present invention, it is preferable that the cured product obtained by curing the epoxy resin composition has a phase-separated structure in order to impart even greater flexibility. From this perspective, the present invention is characterized in that the epoxy resin (A) is used in combination with an epoxy resin (B) having an epoxy equivalent of 100 to 300 g/eq.

The epoxy resin (B) may have an epoxy equivalent in the range of 100 to 300 g/eq, and its structure is not limited. For example, liquid epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD type epoxy resin, polyhydroxybenzene type epoxy resin, polyhydroxynaphthalene type epoxy resin, biphenyl type epoxy resin, and tetramethylbiphenyl type epoxy resin, brominated epoxy resins such as brominated phenol novolac type epoxy resin, solid bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene type epoxy resin, and the like. Examples of such epoxy resins include butadiene-phenol addition reaction type epoxy resins, phenol aralkyl type epoxy resins, phenylene ether type epoxy resins, naphthylene ether type epoxy resins, naphthol novolac type epoxy resins, naphthol aralkyl type epoxy resins, naphthol-phenol co-condensed novolac type epoxy resins, naphthol-cresol co-condensed novolac type epoxy resins, aromatic hydrocarbon formaldehyde resin modified phenolic resin type epoxy resins, biphenyl modified novolac type epoxy resins, and the like. These may be used alone or in combination of two or more kinds, and it is preferable to select and use various types depending on the intended use and physical properties of the cured product.

Among these, it is preferable to use liquid epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD type epoxy resin, polyhydroxybenzene type epoxy resin, polyhydroxynaphthalene type epoxy resin, biphenyl type epoxy resin, and tetramethylbiphenyl type epoxy resin, with an epoxy equivalent of 100 to 300 g/eq. It is particularly preferable to use liquid epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, and bisphenol AD type epoxy resin, with an epoxy equivalent of 100 to 300 g/eq.

In the present invention, the ratio of the epoxy resin (A) to the epoxy resin (B) is not particularly limited, but from the viewpoint of facilitating phase separation in the cured product, the mass ratio (A):(B) of the epoxy resin (A) to the epoxy resin (B) is 97:3 to 3:97, preferably 10:90 to 90:10, and particularly preferably 80:20 to 20:80. Phase separation in the cured product results in a sea-island structure, which balances the adhesiveness and stress relaxation ability of the cured product, exerts high adhesive strength over a particularly wide temperature range, and has the effect of reducing the molding shrinkage rate before and after heat curing of the resin composition.

The phase separation structure is formed spontaneously during the curing reaction based on the compatibility between the epoxy resin (A) and the epoxy resin (B), and is generally a phase separation structure consisting of resin particles with an average particle size of 10 nm to 100 μm and a matrix surrounding the resin particles. At this time, which epoxy resin is the cured product that forms the resin particles and which is the cured product that forms the matrix? This is determined by the blending ratio, the type of curing agent, or the effect conditions. In other words, the resin particles may contain the cured product of the epoxy resin (A) and the matrix may contain the cured product of the epoxy resin (B), or the resin particles may contain the cured product of the epoxy resin (B) and the matrix may contain the cured product of the epoxy resin (A).

The phase separation structure of the cured material can be observed with a scanning electron microscope (SEM) or an atomic force microscope (AFM), and when a sea-island structure is formed, the particle size of the islands can be measured. In the present invention, the average particle size of the resin particles is determined by randomly selecting 50 islands from the islands within a field of view of 200 μm x 260 μm, measuring the particle size, and averaging the results to determine the average particle size. In addition, the relative hardness distribution of the sea and islands can be confirmed from AFM observation.

The epoxy resin composition of the present invention preferably further contains a curing agent (C) that can react with general epoxy resins.

The curing agent (C) is not particularly limited, and examples thereof include amine compounds, acid anhydrides, amide compounds, phenolic hydroxyl group-containing compounds, carboxylic acid compounds, and hydroxy compounds that are precursors of the aforementioned epoxy resin (A).

Examples of the amine compounds include aliphatic amine compounds such as trimethylenediamine, ethylenediamine, N,N,N',N'-tetramethylethylenediamine, pentamethyldiethylenetriamine, triethylenediamine, dipropylenediamine, N,N,N',N'-tetramethylpropylenediamine, tetramethylenediamine, pentanediamine, hexamethylenediamine, trimethylhexamethylenediamine, N,N,N',N'-tetramethylhexamethylenediamine, N,N-dimethylcyclohexylamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dimethylaminopropylamine, diethylaminopropylamine, dibutylaminopropylamine, 1,4-diazabicyclo(2,2,2)octane(triethylenediamine), polyoxyethylenediamine, polyoxypropylenediamine, bis(2-dimethylaminoethyl)ether, dimethylaminoethoxyethoxyethanol, triethanolamine, and dimethylaminohexanol;

Alicyclic and heterocyclic amine compounds such as piperidine, piperazine, menthanediamine, isophoronediamine, methylmorpholine, ethylmorpholine, N,N',N"-tris(dimethylaminopropyl)hexahydro-s-triazine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxyspiro(5,5)undecane adduct, N-aminoethylpiperazine, trimethylaminoethylpiperazine, bis(4-aminocyclohexyl)methane, N,N'-dimethylpiperazine, and 1,8-diazabicyclo-[5.4.0]-undecene (DBU);

Aromatic amine compounds such as o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, benzylmethylamine, dimethylbenzylamine, m-xylylenediamine, pyridine, picoline, and α-methylbenzylmethylamine;

Examples of modified amine compounds include epoxy compound-added polyamines, Michael addition polyamines, Mannich addition polyamines, thiourea addition polyamines, ketone-blocked polyamines, dicyandiamide, guanidine, organic acid hydrazides, diaminomaleonitrile, aminimides, boron trifluoride-piperidine complexes, and boron trifluoride-monoethylamine complexes.

Examples of the acid anhydride include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, maleic polypropylene glycol anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

Examples of the phenolic hydroxyl group-containing compound include polyhydric phenol compounds such as phenol novolac resin, cresol novolac resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin, dicyclopentadiene phenol addition type resin, phenol aralkyl resin (Zylok resin), naphthol aralkyl resin, trimethylolmethane resin, tetraphenylolethane resin, naphthol novolac resin, naphthol-phenol co-condensed novolac resin, naphthol-cresol co-condensed novolac resin, biphenyl-modified phenol resin (a polyhydric phenol compound in which the phenol nucleus is linked by a bismethylene group), biphenyl-modified naphthol resin (a polyhydric naphthol compound in which the phenol nucleus is linked by a bismethylene group), aminotriazine-modified phenol resin (a polyhydric phenol compound in which the phenol nucleus is linked by melamine, benzoguanamine, etc.), and alkoxy group-containing aromatic ring-modified novolac resin (a polyhydric phenol compound in which the phenol nucleus and the alkoxy group-containing aromatic ring are linked by formaldehyde).

Examples of the amide-based compounds include dicyandiamide and polyamidoamine. Examples of the polyamidoamine include those obtained by reacting an aliphatic dicarboxylic acid such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, or azelaic acid, or a carboxylic acid compound such as a fatty acid or dimer acid, with an aliphatic polyamine or a polyamine having a polyoxyalkylene chain.

Examples of the carboxylic acid compound include carboxylic acid polymers such as carboxylic acid-terminated polyester, polyacrylic acid, and maleic acid-modified polypropylene glycol.

When using these curing agents, only one type of curing agent may be used, or two or more types may be mixed. For applications such as underfill materials and general coating applications, it is preferable to use the amine compounds, carboxylic acid compounds, and/or acid anhydride compounds. For applications as adhesives or flexible wiring boards, amine compounds, particularly dicyandiamide, are preferred in terms of workability, curability, and long-term stability. For applications as semiconductor encapsulation materials, solid phenol compounds are preferred in terms of the heat resistance of the cured product.

The resin composition of the present invention may contain resins other than the epoxy resin (A) and the epoxy resin (B) as long as the effects of the present invention are not impaired.

<Other epoxy resins>
In the resin composition of the present invention, other epoxy resins may be used in combination with the epoxy resin (A) and the epoxy resin (B) as long as the effects of the present invention are not impaired. In this case, the total amount of the epoxy resin (A) and the epoxy resin (B) in the composition of the present invention is preferably 30% by mass or more, and particularly preferably 40% by mass or more, of the total epoxy resins.

Epoxy resins that can be used in combination are not limited in any way as long as they do not belong to the above-mentioned epoxy resin (A) and epoxy resin (B), and examples thereof include liquid epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD type epoxy resin, polyhydroxybenzene type epoxy resin, polyhydroxynaphthalene type epoxy resin, biphenyl type epoxy resin, and tetramethylbiphenyl type epoxy resin, brominated epoxy resins such as brominated phenol novolac type epoxy resin, solid bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenylmethane type Examples of epoxy resins include epoxy resins, tetraphenylethane type epoxy resins, dicyclopentadiene-phenol addition reaction type epoxy resins, phenol aralkyl type epoxy resins, phenylene ether type epoxy resins, naphthylene ether type epoxy resins, naphthol novolac type epoxy resins, naphthol aralkyl type epoxy resins, naphthol-phenol co-condensed novolac type epoxy resins, naphthol-cresol co-condensed novolac type epoxy resins, aromatic hydrocarbon formaldehyde resin modified phenolic resin type epoxy resins, biphenyl modified novolac type epoxy resins, etc. These may be used alone or in combination of two or more kinds, and it is preferable to select and use various types depending on the intended use and physical properties of the cured product.

The amounts of epoxy resin and curing agent in the composition of the present invention are not particularly limited, but in order to obtain good mechanical properties of the cured product, it is preferable to use an amount in which the active groups in the curing agent are 0.4 to 1.5 equivalents per equivalent of epoxy groups in the total amount of epoxy resin including epoxy resin (A) and epoxy resin (B).

<Curing accelerator>
The epoxy resin composition of the present invention may contain a curing accelerator. Various types of curing accelerators can be used, including urea compounds, phosphorus compounds, tertiary amines, imidazole, organic acid metal salts, Lewis acids, and amine complex salts. When used as an adhesive, urea compounds, particularly 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), are preferred because of their excellent workability and low-temperature curing properties. When used as a semiconductor encapsulating material, triphenylphosphine is a phosphorus compound, and 1,8-diazabicyclo-[5.4.0]-undecene is a tertiary amine, which are preferred because of their excellent curing properties, heat resistance, electrical properties, and moisture resistance reliability.

<Filler>
The epoxy resin composition of the present invention may further contain a filler. Examples of the filler include inorganic fillers and organic fillers. Examples of the inorganic filler include inorganic fine particles.

Examples of inorganic fine particles include those with excellent heat resistance, such as alumina, magnesia, titania, zirconia, and silica (quartz, fumed silica, precipitated silica, silicic anhydride, fused silica, crystalline silica, and ultrafine amorphous silica); those with excellent thermal conductivity, such as boron nitride, aluminum nitride, alumina oxide, titanium oxide, magnesium oxide, zinc oxide, silicon oxide, and diamond; those with excellent electrical conductivity, such as metal fillers and/or metal-coated fillers using simple metals or alloys (e.g., iron, copper, magnesium, aluminum, gold, silver, platinum, zinc, manganese, and stainless steel); and those with excellent barrier properties, such as minerals such as mica, clay, kaolin, talc, zeolite, wollastonite, and smectite, potassium titanate, magnesium sulfate, sepiolite, zonolite, and the like. , aluminum borate, calcium carbonate, titanium oxide, barium sulfate, zinc oxide, magnesium hydroxide; those with a high refractive index include barium titanate, zirconia oxide, titanium oxide, etc.; those that exhibit photocatalytic properties include photocatalytic metals such as titanium, cerium, zinc, copper, aluminum, tin, indium, phosphorus, carbon, sulfur, ruthenium, nickel, iron, cobalt, silver, molybdenum, strontium, chromium, barium, lead, etc., composites of the above metals, and oxides thereof; those with excellent abrasion resistance include metals such as silica, alumina, zirconia, magnesium oxide, etc., and composites and oxides thereof; those with excellent conductivity include metals such as silver and copper, tin oxide, indium oxide, etc.; those with excellent insulation properties include silica, etc.; those with excellent ultraviolet shielding properties include titanium oxide, zinc oxide, etc.

These inorganic particles can be selected according to the application, and may be used alone or in combination. In addition, the inorganic particles have various properties in addition to those listed as examples, so they can be selected according to the application.

For example, when silica is used as the inorganic fine particles, known silica fine particles such as powdered silica and colloidal silica can be used without any particular limitation. Examples of commercially available powdered silica fine particles include Aerosil 50 and 200 manufactured by Nippon Aerosil Co., Ltd., Sildex H31, H32, H51, H52, H121, and H122 manufactured by Asahi Glass Co., Ltd., E220A and E220 manufactured by Nippon Silica Industry Co., Ltd., SYLYSIA 470 manufactured by Fuji Silysia Co., Ltd., and SG Flake manufactured by Nippon Sheet Glass Co., Ltd.

Examples of commercially available colloidal silica include methanol silica sol, IPA-ST, MEK-ST, NBA-ST, XBA-ST, DMAC-ST, ST-UP, ST-OUP, ST-20, ST-40, ST-C, ST-N, ST-O, ST-50, and ST-OL manufactured by Nissan Chemical Industries, Ltd.

Surface-modified silica particles may be used, for example, silica particles that have been surface-treated with a reactive silane coupling agent having a hydrophobic group, or silica particles that have been modified with a compound having a (meth)acryloyl group. Examples of commercially available powdered silica modified with a compound having a (meth)acryloyl group include Aerosil RM50 and R711 manufactured by Nippon Aerosil Co., Ltd., and examples of commercially available colloidal silica modified with a compound having a (meth)acryloyl group include MIBK-SD manufactured by Nissan Chemical Industries, Ltd.

The shape of the silica fine particles is not particularly limited, and spherical, hollow, porous, rod-like, plate-like, fibrous, or amorphous shapes can be used. The primary particle diameter is preferably in the range of 5 to 200 nm. If the diameter is less than 5 nm, the inorganic fine particles in the dispersion will not be sufficiently dispersed, and if the diameter exceeds 200 nm, the cured product may not maintain sufficient strength.

As titanium oxide fine particles, not only extender pigments but also ultraviolet light responsive photocatalysts can be used, such as anatase type titanium oxide, rutile type titanium oxide, and brookite type titanium oxide. Furthermore, particles designed to respond to visible light by doping different elements into the crystal structure of titanium oxide can also be used. As elements to be doped into titanium oxide, anionic elements such as nitrogen, sulfur, carbon, fluorine, and phosphorus, and cationic elements such as chromium, iron, cobalt, and manganese are preferably used. In addition, as a form, powder, sol dispersed in an organic solvent or water, or slurry can be used. Examples of commercially available powdered titanium oxide fine particles include Aerosil P-25 manufactured by Nippon Aerosil Co., Ltd. and ATM-100 manufactured by Teika Co., Ltd. Examples of commercially available slurry-type titanium oxide fine particles include TKD-701 manufactured by Teika Co., Ltd.

<Fibre substrate>
The resin composition of the present invention may further contain a fibrous substrate. The fibrous substrate of the present invention is not particularly limited, but is preferably one used in fiber-reinforced resins, such as inorganic fibers and organic fibers.

Examples of inorganic fibers include inorganic fibers such as carbon fibers, glass fibers, boron fibers, alumina fibers, and silicon carbide fibers, as well as carbon fibers, activated carbon fibers, graphite fibers, tungsten carbide fibers, silicon carbide fibers (silicon carbide fibers), ceramic fibers, natural fibers, mineral fibers such as basalt, boron nitride fibers, boron carbide fibers, and metal fibers. Examples of the metal fibers include aluminum fibers, copper fibers, brass fibers, stainless steel fibers, and steel fibers.

Examples of organic fibers include synthetic fibers made from resin materials such as polybenzazole, aramid, PBO (polyparaphenylene benzoxazole), polyphenylene sulfide, polyester, acrylic, polyamide, polyolefin, polyvinyl alcohol, and polyarylate; natural fibers such as cellulose, pulp, cotton, wool, and silk; and regenerated fibers such as proteins, polypeptides, and alginic acid.

Among these, carbon fiber and glass fiber are preferred because they have a wide range of industrial applications. Only one of these may be used, or multiple types may be used simultaneously.

The fibrous substrate of the present invention may be an assembly of fibers, and may be continuous or discontinuous, and may be in the form of a woven or nonwoven fabric. It may also be a fiber bundle in which the fibers are aligned in one direction, or a sheet in which the fiber bundles are arranged. It may also be a three-dimensional shape in which the fiber assembly has a certain thickness.

<Dispersion medium>
The resin composition of the present invention may contain a dispersion medium for the purpose of adjusting the solid content and viscosity of the resin composition. The dispersion medium may be any liquid medium that does not impair the effects of the present invention, and examples of the dispersion medium include various organic solvents and liquid organic polymers.

Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK); cyclic ethers such as tetrahydrofuran (THF) and dioxolane; esters such as methyl acetate, ethyl acetate, and butyl acetate; aromatics such as toluene and xylene; and alcohols such as carbitol, cellosolve, methanol, isopropanol, butanol, and propylene glycol monomethyl ether. These can be used alone or in combination, but of these, methyl ethyl ketone is preferred from the standpoint of volatility during coating and solvent recovery.

The liquid organic polymer is a liquid organic polymer that does not directly contribute to the curing reaction, and examples thereof include modified carboxyl group-containing polymers (Floren G-900, NC-500: Kyoeisha), acrylic polymers (Floren WK-20: Kyoeisha), amine salts of special modified phosphate esters (HIPLAAD ED-251: Kusumoto Chemicals), modified acrylic block copolymers (DISPERBYK2000; BYK-Chemie), etc.

<Resin>
The resin composition of the present invention may contain a resin other than the various compounds described above. As the resin, a known and commonly used resin may be blended as long as it does not impair the effects of the present invention, and for example, a thermosetting resin or a thermoplastic resin may be used.

Thermosetting resins are resins that have the property of becoming substantially insoluble and infusible when cured by heating, radiation, catalysts, or other means. Specific examples include phenolic resins, urea resins, melamine resins, benzoguanamine resins, alkyd resins, unsaturated polyester resins, vinyl ester resins, diallyl terephthalate resins, silicone resins, urethane resins, furan resins, ketone resins, xylene resins, thermosetting polyimide resins, benzoxazine resins, active ester resins, aniline resins, cyanate ester resins, styrene-maleic anhydride (SMA) resins, and maleimide resins. These thermosetting resins can be used alone or in combination of two or more.

Thermoplastic resins are resins that can be melt-molded by heating. Specific examples include polyethylene resin, polypropylene resin, polystyrene resin, rubber-modified polystyrene resin, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, polymethyl methacrylate resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyethylene terephthalate resin, ethylene vinyl alcohol resin, cellulose acetate resin, ionomer resin, polyacrylonitrile resin, polyamide resin, polyacetal resin, polybutylene terephthalate resin, polylactic acid resin, polyphenylene ether resin, modified polyphenylene ether resin, polycarbonate resin, polysulfone resin, polyphenylene sulfide resin, polyetherimide resin, polyethersulfone resin, polyarylate resin, thermoplastic polyimide resin, polyamideimide resin, polyetheretherketone resin, polyketone resin, liquid crystal polyester resin, fluororesin, syndiotactic polystyrene resin, and cyclic polyolefin resin. These thermoplastic resins can be used alone or in combination of two or more.

<Other ingredients>
The resin composition of the present invention may contain other compounds, such as catalysts, polymerization initiators, inorganic pigments, organic pigments, extender pigments, clay minerals, waxes, surfactants, stabilizers, flow control agents, coupling agents, dyes, leveling agents, rheology control agents, ultraviolet absorbers, antioxidants, flame retardants, plasticizers, and reactive diluents.

<Cured Product>
The resin composition of the present invention can be cured to obtain a cured product. The curing can be performed at room temperature or by heating. A known and commonly used curing catalyst may be used for curing.
When the heat curing is carried out, the composition may be cured by a single heating step or may be cured through multiple heating steps.

When a curing catalyst is used, for example, inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, etc.; organic acids such as p-toluenesulfonic acid, monoisopropyl phosphate, acetic acid, etc.; inorganic bases such as sodium hydroxide or potassium hydroxide; titanate esters such as tetraisopropyl titanate, tetrabutyl titanate, etc.; chemical compounds containing basic nitrogen atoms such as 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), 1,5-diazabicyclo[4.3.0]nonene-5 (DBN), 1,4-diazabicyclo[2.2.2]octane (DABCO), tri-n-butylamine, dimethylbenzylamine, monoethanolamine, imidazole, 2-ethyl-4-methyl-imidazole, 1-methylimidazole, N,N-dimethyl-4-aminopyridine (DMAP), etc. compounds; various quaternary ammonium salts such as tetramethylammonium salts, tetrabutylammonium salts, and dilauryldimethylammonium salts, which have a counter anion such as chloride, bromide, carboxylate, or hydroxide; tin carboxylates such as dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin diacetylacetonate, tin octoate, or tin stearate; organic peroxides such as benzoyl peroxide, cumene hydroperoxide, dicumyl peroxide, lauroyl peroxide, di-t-butyl peroxide, t-butyl hydroperoxide, methyl ethyl ketone peroxide, and t-butyl perbenzoate. The catalysts may be used alone or in combination of two or more.

The composition of the present invention can also be cured by active energy rays. In that case, a photocationic polymerization initiator can be used as the polymerization initiator. Examples of active energy rays that can be used include visible light, ultraviolet light, X-rays, and electron beams.

Examples of photocationic polymerization initiators include aryl-sulfonium salts and aryl-iodonium salts. Specifically, arylsulfonium hexafluorophosphate, arylsulfonium hexafluoroantimonate, arylsulfonium tetrakis(pentafluoro)borate, tri(alkylphenyl)sulfonium hexafluorophosphate, etc. can be used. The photocationic polymerization initiators may be used alone or in combination of two or more.

<Laminate>
The cured product of the present invention can be laminated with a substrate to form a laminate.
The substrate of the laminate may be inorganic material such as metal or glass, or organic material such as plastic or wood, which may be used as appropriate depending on the application. The shape of the laminate may be flat, sheet-like, or may have a three-dimensional structure or may be solid. Any shape may be used depending on the purpose, such as one having a curvature over the entire surface or part. There is also no restriction on the hardness, thickness, etc. of the substrate. The cured product of the present invention may be used as a substrate, and the cured product of the present invention may be further laminated.

A multilayer laminate may also be obtained by laminating a substrate, a cured product layer, and a second substrate in this order. Since the resin composition of the present invention has excellent adhesive properties, it can be suitably used as an adhesive for bonding a substrate and a second substrate.

The resin composition of the present invention has particularly high adhesion to metals and/or metal oxides, and can be particularly well used as a primer for metals. Metals include copper, aluminum, gold, silver, iron, platinum, chromium, nickel, tin, titanium, zinc, various alloys, and composite materials of these, while metal oxides include single oxides and/or composite oxides of these metals. Since the resin composition has particularly excellent adhesion to iron, copper, and aluminum, it can be particularly well used as an adhesive for iron, copper, and aluminum.

In addition, since the resin composition of the present invention can relieve stress, it is particularly suitable for use in bonding dissimilar materials. For example, even if the substrate is a metal and/or metal oxide and the second substrate is a laminate of dissimilar materials such as a plastic layer, the adhesive strength is maintained due to the stress relaxation ability of the resin composition.

In the laminate of the present invention, the cured product layer may be formed by direct coating or molding on the substrate, or an already molded product may be laminated. When directly coating, the coating method is not particularly limited, and examples include spraying, spin coating, dip coating, roll coating, blade coating, doctor roll coating, doctor blade coating, curtain coating, slit coating, screen printing, and inkjet coating. When directly molding, examples include in-mold molding, insert molding, vacuum molding, extrusion lamination molding, and press molding.

When laminating a molded resin composition, an uncured or semi-cured resin composition layer may be laminated and then cured, or a cured layer of the composition that has been completely cured may be laminated onto the substrate.

A precursor capable of serving as a substrate may be applied to the cured product of the present invention and then cured to form a laminate, or the precursor capable of serving as a substrate or the composition of the present invention may be adhered in an uncured or semi-cured state and then cured. There are no particular limitations on the precursor capable of serving as a substrate, and examples include various curable resin compositions.

<Fiber reinforced resin>
When the resin composition of the present invention has a fibrous substrate, and the fibrous substrate is a reinforcing fiber, the composition containing the fibrous substrate can be used as a fiber-reinforced resin.
The method of incorporating a fibrous substrate into the composition is not particularly limited as long as it does not impair the effects of the present invention. Examples of the method include combining the fibrous substrate with the composition by kneading, coating, impregnation, injection, compression bonding, etc., and can be selected as appropriate depending on the form of the fiber and the application of the fiber-reinforced resin.

There is no particular limitation on the method of molding the fiber-reinforced resin of the present invention. If a plate-shaped product is to be manufactured, extrusion molding is generally used, but it can also be manufactured by flat pressing. Other methods that can be used include extrusion molding, blow molding, compression molding, vacuum molding, injection molding, etc. If a film-shaped product is to be manufactured, in addition to melt extrusion, solution casting can be used. When using a melt molding method, examples include inflation film molding, cast molding, extrusion lamination molding, calendar molding, sheet molding, fiber molding, blow molding, injection molding, rotational molding, and coating molding. In addition, in the case of a resin that is cured by active energy rays, a cured product can be manufactured using various curing methods using active energy rays. In particular, when the matrix resin is mainly composed of a thermosetting resin, a molding method in which the molding material is made into a prepreg and pressurized and heated using a press or autoclave is exemplified. Other examples include RTM (Resin Transfer Molding) molding, VaRTM (Vacuum Assist Resin Transfer Molding) molding, laminate molding, hand layup molding, etc.

<Prepreg>
The fiber reinforced resin of the present invention can form a state called an uncured or semi-cured prepreg. After distributing the product in the prepreg state, final curing may be performed to form a cured product. When forming a laminate, it is preferable to form a prepreg, laminate other layers, and then perform final curing, since this allows the formation of a laminate in which each layer is in close contact with each other.
The mass ratio of the composition and the fibrous substrate used in this case is not particularly limited, but it is usually preferable to prepare the prepreg so that the resin content is 20 to 60 mass %.

<Heat-resistant materials and electronic materials>
The resin composition of the present invention can be suitably used for heat-resistant members because the cured product has a high glass transition temperature and excellent thermal decomposition resistance. In addition, since the resin composition has excellent adhesion to the substrate, it can be suitably used for electronic members in particular. In particular, it can be suitably used for semiconductor encapsulation materials, circuit boards, build-up films, build-up boards, adhesives, and resist materials. It can also be suitably used for matrix resins of fiber-reinforced resins, and is particularly suitable as a highly heat-resistant prepreg. The heat-resistant members and electronic members thus obtained can be suitably used for various applications, such as industrial machine parts, general machine parts, automobile, railway, and vehicle parts, space and aviation-related parts, electronic and electrical parts, building materials, containers and packaging parts, daily necessities, sports and leisure goods, and housing parts for wind power generation, but are not limited thereto.

Below, we will explain some representative products using examples.

1. Semiconductor encapsulating material As a method for obtaining a semiconductor encapsulating material from the resin composition of the present invention, the resin composition, the curing accelerator, and compounding agents such as inorganic fillers are melt-mixed sufficiently until homogeneous using an extruder, kneader, roll, etc. as necessary. In this case, fused silica is usually used as the inorganic filler, but when used as a high thermal conductivity semiconductor encapsulating material for power transistors and power ICs, it is preferable to use highly filled crystalline silica, alumina, silicon nitride, etc., which have a higher thermal conductivity than fused silica, or fused silica, crystalline silica, alumina, silicon nitride, etc. The filling rate is preferably in the range of 30 to 95 mass% per 100 parts by mass of the curable resin composition, and among them, in order to improve flame retardancy, moisture resistance, and solder crack resistance and to reduce the linear expansion coefficient, it is more preferable that the inorganic filler is 70 parts by mass or more, and even more preferable that the inorganic filler is 80 parts by mass or more.

2. Semiconductor Device [0043] Examples of semiconductor package molding for obtaining a semiconductor device from the curable resin composition of the present invention include a method in which the semiconductor encapsulating material is molded by casting, or using a transfer molding machine, an injection molding machine, or the like, and then heated at 50 to 250°C for 2 to 10 hours.

3. Printed Circuit Board [0043] A method for obtaining a printed circuit board from the composition of the present invention includes laminating the above prepreg by a conventional method, appropriately overlaying copper foil, and subjecting the laminate to heat-pressure bonding at 170 to 300°C under a pressure of 1 to 10 MPa for 10 minutes to 3 hours.

4. Build-up Substrate The method for obtaining a build-up substrate from the composition of the present invention includes, for example, the following steps. First, the above composition, which is appropriately blended with rubber, filler, etc., is applied to a circuit board on which a circuit is formed by using a spray coating method, a curtain coating method, etc., and then cured (step 1). Thereafter, a predetermined through-hole portion or the like is drilled as necessary, and then the surface is treated with a roughening agent, and the surface is washed with hot water to form unevenness, and then a metal such as copper is plated (step 2). These operations are repeated as desired to alternately build up resin insulating layers and conductor layers of a predetermined circuit pattern (step 3). The through-hole portion is drilled after the formation of the outermost resin insulating layer. In addition, the build-up substrate of the present invention can also be produced by forming a roughened surface by heating and pressing the resin-coated copper foil, which is obtained by semi-curing the resin composition on the copper foil, onto a wiring board on which a circuit is formed, at 170 to 300°C, thereby forming a build-up substrate without the steps of plating.

A build-up film can be obtained from the composition of the present invention by applying the composition to the surface of a support film (Y) as a substrate, and then drying the organic solvent by heating or blowing hot air thereon to form a layer of the composition (X).

The organic solvents used here preferably include, for example, ketones such as acetone, methyl ethyl ketone, and cyclohexanone; acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; and it is preferable to use the solvent in a proportion that results in a non-volatile content of 30 to 60% by mass.

The thickness of the layer (X) formed is usually equal to or greater than the thickness of the conductor layer. Since the thickness of the conductor layer of the circuit board is usually in the range of 5 to 70 μm, the thickness of the resin composition layer is preferably 10 to 100 μm. The layer (X) of the composition in the present invention may be protected with a protective film, which will be described later. By protecting the layer with a protective film, it is possible to prevent the adhesion of dirt and the like to the surface of the resin composition layer and prevent scratches.

The above-mentioned support film and protective film may be made of polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate; polycarbonate; polyimide; and even release paper and metal foils such as copper foil and aluminum foil. The support film and protective film may be subjected to a matte treatment, corona treatment, or release treatment. The thickness of the support film is not particularly limited, but is usually 10 to 150 μm, and preferably 25 to 50 μm. The thickness of the protective film is preferably 1 to 40 μm.

The support film (Y) is peeled off after lamination onto the circuit board or after forming an insulating layer by heat curing. If the support film (Y) is peeled off after the curable resin composition layer constituting the build-up film is heat cured, the adhesion of dust and the like during the curing process can be prevented. When peeling off after curing, the support film is usually subjected to a release treatment in advance.

A multilayer printed circuit board can be manufactured using the build-up film obtained as described above. For example, when the layer (X) is protected by a protective film, the protective film is peeled off, and then the layer (X) is laminated on one or both sides of the circuit board so as to be in direct contact with the circuit board, for example, by a vacuum lamination method. The lamination method may be a batch type or a continuous type using a roll. If necessary, the build-up film and the circuit board may be heated (preheated) before lamination. The lamination conditions are preferably a pressure bonding temperature (lamination temperature) of 70 to 140°C, a pressure bonding pressure of 1 to 11 kgf/cm ² (9.8×10 ⁴ to 107.9×10 ⁴ N/m ² ), and lamination is preferably performed under reduced pressure of 20 mmHg (26.7 hPa) or less.

6. Conductive Paste As a method for obtaining a conductive paste from the composition of the present invention, for example, a method of dispersing conductive particles in the composition can be mentioned. The conductive paste can be a paste resin composition for circuit connection or an anisotropic conductive adhesive depending on the type of conductive particles used.

Next, the present invention will be described in detail with reference to examples and comparative examples. In the following, "parts" and "%" are by weight unless otherwise specified.

¹ H and ¹³ C-NMR, FD-MS spectra, and GPC were measured under the following conditions.

¹ H-NMR: “JNM-ECA600” manufactured by JEOL RESONANCE
Magnetic field strength: 600MHz
Number of times of accumulation: 32 Solvent: DMSO- _d6
Sample concentration: 30% by mass

^13C -NMR: “JNM-ECA600” manufactured by JEOL RESONANCE
Magnetic field strength: 150MHz
Number of times of accumulation: 320 Solvent: DMSO- _d6
Sample concentration: 30% by mass

FD-MS: "JMS-T100GC AccuTOF" manufactured by JEOL Ltd.
Measurement range: m / z = 50.00 to 2000.00
Rate of change: 25.6mA/min
Final current value: 40mA
Cathode voltage: -10 kV

GPC: Tosoh Corporation "HLC-8320GPC"
Column: "TSK-GEL G2000HXL" + "TSK-GEL G3000HXL" + "TSK-GEL G4000HXL" manufactured by Tosoh Corporation
Detector: RI (differential refractometer)
Measurement condition: 40°C
Mobile phase: tetrahydrofuran Flow rate: 1 ml/min
Standard: Tosoh Corporation "PStQuick A", "PStQuick B", "PStQuick E", "PStQuick F"

The epoxy equivalent of the synthesized epoxy resin was measured according to JIS K7236, and the epoxy equivalent (g/eq) was calculated.

Examples of methods for calculating the number of repeating units include calculation from the results of appropriate instrumental analysis such as GPC molecular weight measurement, FD-MS, and NMR.

[Synthesis Example 1]
A flask equipped with a thermometer and a stirrer was charged with 136 g (0.43 mol) of diglycidyl ether of 1,6-hexanediol ("SR-16H" manufactured by Sakamoto Yakuhin: epoxy equivalent 160 g/eq), 66 g (0.07 mol) of diglycidyl ether of polytetramethylene glycol ("Denacol EX-991L" manufactured by Nagase ChemteX: epoxy equivalent 445 g/eq), and 119.7 g (0.53 mol) of bisphenol A (hydroxyl equivalent 114 g/eq), and the temperature was raised to 140°C for 30 minutes, after which 3.2 g of a 20% aqueous sodium hydroxide solution was charged. The temperature was then raised to 150°C for 30 minutes, and the mixture was further reacted at 150°C for 20 hours. Thereafter, a neutralizing amount of sodium phosphate was added, and 320 g of a hydroxy compound (Ph-1) was obtained. This hydroxy compound (Ph-1) was confirmed to contain the target hydroxy compound because a peak of M+=1839 was obtained in the mass spectrum, which corresponds to the theoretical structure of structural formula (Ph-1) in which n ₁ =6, m ₁ =1, n ₂ =11, and m ₂ =1. The hydroxyl equivalent of this hydroxy compound (Ph-1) calculated by GPC was 1896 g/eq.

[Synthesis Example 2]
In a flask equipped with a thermometer and a stirrer, 126.2 g (0.39 mol) of diglycidyl ether of 1,6-hexanediol ("SR-16H" manufactured by Sakamoto Yakuhin: epoxy equivalent 160 g/eq), 78.1 g (0.08 mol) of diglycidyl ether of polypropylene glycol ("Denacol EX-931" manufactured by Nagase ChemteX: epoxy equivalent 481 g/eq), and 114.6 g (0.50 mol) of bisphenol A (hydroxyl equivalent 114 g/eq) were charged, and the temperature was raised to 140°C over 30 minutes, after which 3.2 g of a 20% aqueous sodium hydroxide solution was charged. The subsequent operations were carried out in the same manner as in Synthesis Example 1, and 317 g of a hydroxy compound (Ph-2) was obtained. This hydroxy compound (Ph-2) was confirmed to contain the target hydroxy compound _because a peak at M+=1684 was confirmed in the mass spectrum, which corresponds to the theoretical structure of structural formula (Ph-2) in which n 1 =6, m ₁ =1, n ₂ =11, and m ₂ =1. The hydroxyl equivalent of this hydroxy compound (Ph-2) calculated by GPC was 1597 g/eq.

[Synthesis Example 3]
In a flask equipped with a thermometer and a stirrer, 179 g (0.56 mol) of diglycidyl ether of 1,6-hexanediol ("SR-16H" manufactured by Sakamoto Yakuhin: epoxy equivalent 160 g/eq) and 133.6 g (0.59 mol) of bisphenol A (hydroxyl equivalent 114 g/eq) were charged, and the temperature was raised to 140°C over 30 minutes, after which 3.2 g of a 20% aqueous sodium hydroxide solution was charged. The subsequent operations were carried out in the same manner as in Synthesis Example 1, and 305 g of a hydroxy compound (Ph-2) was obtained. This hydroxy compound (Ph-3) was confirmed to contain the hydroxy compound of interest, since a peak of M+=687 corresponding to the theoretical structure of n ₁ =6, m ₁ =1 in the structural formula (Ph-3) was confirmed in the mass spectrum. The hydroxyl equivalent of this hydroxy compound (Ph-3) calculated from GPC was 2244 g/eq.

[Synthesis Example 4]
In a flask equipped with a thermometer and a stirrer, 195 g (0.22 mol) of diglycidyl ether of polytetramethylene glycol ("Denacol EX-991L" manufactured by Nagase ChemteX: epoxy equivalent 445 g/eq) and 59.9 g (0.26 mol) of bisphenol A (hydroxyl equivalent 114 g/eq) were charged, and the temperature was raised to 140°C over 30 minutes, after which 2.5 g of a 20% aqueous sodium hydroxide solution was charged. The subsequent operations were carried out in the same manner as in Synthesis Example 1, and 250 g of a hydroxy compound (Ph-4) was obtained. This hydroxy compound (Ph-4) was confirmed to contain the target hydroxy compound because a peak of M+=1380, which corresponds to the theoretical structure of M=1, n ₂ =11, and m ₂ =1 in the structural formula (Ph-4), was confirmed in the mass spectrum. The hydroxyl equivalent of this hydroxy compound (Ph-4) calculated by GPC was 2497 g/eq.

[Synthesis Example 5]
In a flask equipped with a thermometer and a stirrer, 230.9 g (0.24 mol) of diglycidyl ether of polypropylene glycol ("Denacol EX-931" manufactured by Nagase ChemteX: epoxy equivalent 481 g/eq) and 65.7 g (0.29 mol) of bisphenol A (hydroxyl equivalent 114 g/eq) were charged, and the temperature was raised to 140°C over 30 minutes, after which 3.0 g of a 20% aqueous sodium hydroxide solution was charged. The subsequent operations were carried out in the same manner as in Synthesis Example 1, and 290 g of a hydroxy compound (Ph-5) was obtained. This hydroxy compound (Ph-5) was confirmed to contain the target hydroxy compound because a peak of M+=1226, which corresponds to the theoretical structure of n ₂ =11 and m ₂ =1 in the structural formula (Ph-5), was confirmed in the mass spectrum. The hydroxyl equivalent of this hydroxy compound (Ph-5) calculated by GPC was 1,447 g/eq.

[Example 1]
In a flask equipped with a thermometer, a dropping funnel, a cooling tube, and a stirrer, 200 g of the hydroxy compound Ph-1 obtained in Synthesis Example 1, 437 g (4.72 mol) of epichlorohydrin, and 118 g of n-butanol were charged and dissolved while purging with nitrogen gas. After heating to 65°C, the pressure was reduced to the pressure at which azeotropy occurred, and 6.66 g (0.08 mol) of a 49% aqueous sodium hydroxide solution was dropped over 5 hours. Stirring was then continued for 0.5 hours under the same conditions. During this time, the distillate that had been distilled by azeotropy was separated using a Dean-Stark trap, the aqueous layer was removed, and the oil layer was returned to the reaction system while the reaction was carried out. Thereafter, unreacted epichlorohydrin was distilled off by reduced pressure distillation. 150 g of methyl isobutyl ketone and 150 g of n-butanol were added to the reaction product obtained and dissolved. Further, 10 g of a 10% aqueous sodium hydroxide solution was added to this solution, and the mixture was reacted at 80° C. for 2 hours, after which the mixture was washed three times with 100 g of water until the pH of the washing liquid became neutral. The system was then dehydrated by azeotropy, and after microfiltration, the solvent was distilled off under reduced pressure to obtain 190 g of epoxy resin Ep-1. The epoxy equivalent of the obtained epoxy _resin Ep-1 was 2167 g/eq. This epoxy resin Ep-1 was confirmed to contain the epoxy resin Ep-1 having the target structure, since a peak of M+=1951 was obtained in the mass spectrum, which corresponds to the theoretical structure of m _{1 =1, n 1} =6, m ₂ =1, n ₂ =11, q= ₁ , p 1 =0, and p ₂ =0 in the following structural formula (Ep-1).

[Example 2]
The same reaction as in Example 1 was carried out, except that 200 g of the hydroxy compound Ph-1 obtained in Synthesis Example 1 was replaced with 200 g of the hydroxy compound Ph-2 obtained in Synthesis Example 2, to obtain 190 g of epoxy resin Ep-2. The epoxy equivalent of the obtained epoxy resin Ep-2 was 1835 g/eq. This epoxy resin Ep-2 was confirmed to contain the target epoxy resin Ep-2, since a peak of M+=1796 was obtained in the mass spectrum, which corresponds to the theoretical structure of m ₁ =1, n ₁ =6, m ₂ =1, n ₂ =11, q=1, p ₁ =0, and p ₂ =0 in the following structural formula (Ep-2).

[Synthesis Example 6]
The same reaction as in Example 1 was carried out, except that 200 g of the hydroxy compound Ph-1 obtained in Synthesis Example 1 was replaced with 200 g of the hydroxy compound Ph-3 obtained in Synthesis Example 3, to obtain 190 g of epoxy resin Ep-3. The epoxy equivalent of the obtained epoxy resin Ep-3 was 2244 g/eq. This epoxy resin Ep-3 was confirmed to contain the target epoxy resin Ep-3, since a peak of M+=799 was obtained in the mass spectrum, which corresponds to the theoretical structure of m ₁ =1, n ₁ =6, q=1, p1=0, and p2=0 in the following structural formula (Ep-3).

[Synthesis Example 7]
The same reaction as in Example 1 was carried out, except that 200 g of the hydroxy compound Ph-1 obtained in Synthesis Example 1 was replaced with 200 g of the hydroxy compound Ph-4 obtained in Synthesis Example 4, to obtain 185 g of epoxy resin Ep-4. The epoxy equivalent of the obtained epoxy resin Ep-4 was 2834 g/eq. This epoxy resin Ep-4 was confirmed to contain the target epoxy resin Ep-4, since a peak of M+=1492 was obtained in the mass spectrum, which corresponds to the theoretical structure of m ₂ =1, n ₂ =11, q=1, p ₁ =0, and p ₂ =0 in the following structural formula (Ep-4).

[Synthesis Example 8]
The same reaction as in Example 1 was carried out, except that 200 g of the hydroxy compound Ph-1 obtained in Synthesis Example 1 was replaced with 200 g of the hydroxy compound Ph-5 obtained in Synthesis Example 5, to obtain 190 g of epoxy resin Ep-5. The epoxy equivalent of the obtained epoxy resin Ep-5 was 1668 g/eq. This epoxy resin Ep-) was confirmed to contain the target epoxy resin Ep-5, since a peak of M+=1338 was obtained in the mass spectrum, which corresponds to the theoretical structure of m ₂ =1, n ₂ =11, q=1, p ₁ =0, p ₂ =0 in the following structural formula (Ep-5).

[Examples 3-6 and Comparative Examples 1-3] Preparation of compositions and cured resins Epoxy resin, curing agent (1.0 equivalent relative to epoxy), curing accelerator (0.85 parts by weight relative to epoxy) and filler (light calcium carbonate, Omi Chemical Industry Co., Ltd.) were mixed uniformly in a mixer (Thinky Corporation's "Awatori Rentaro ARV-200") according to the formulations shown in Tables 1 and 2 to obtain an epoxy resin composition. This epoxy resin composition was sandwiched between aluminum mirror plates (Engineering Test Service Co., Ltd.'s "JIS H 4000 A1050P") using a silicon tube as a spacer and heat cured at 170°C for 30 minutes to obtain a cured resin with a thickness of 0.8 mm.

<Glass transition temperature>
The 0.8 mm thick cured product was cut into a size of 5 mm wide and 40 mm long to prepare a test specimen. The test specimen was measured using a viscoelasticity measuring device (DMA: Hitachi High-Tech Science Corporation solid viscoelasticity measuring device "DMS7100", deformation mode: tension, measurement mode: sinusoidal vibration, frequency 1 Hz, heating rate 3°C/min), and the temperature at which the change in elastic modulus was maximum (the rate of change in tan δ was the largest) was evaluated as the glass transition temperature. When multiple peak tops were present, they were listed in the table as multiple glass transition temperatures.

<Tensile test>
The cured resin was punched out into a dumbbell shape (JIS K 7161-2-1BA) using a punching blade to prepare a test piece. The test piece was subjected to a tensile test in accordance with JIS K 7162-2 using a tensile tester (Shimadzu Corporation's "Autograph AG-IS") to evaluate the elongation at break in a measurement environment of 23°C (test speed: 2 mm/min).

<Tensile shear test>
The resin composition was applied to one of two cold-rolled steel plates ("SPCC-SB" manufactured by TP Giken Co., Ltd., 1.0 mm x 25 mm x 100 mm), glass beads ("J-80" manufactured by Potters Ballotini Co., Ltd.) were added as spacers, and the other SPCC-SB was attached (adhesive area: 25 mm x 12.5 mm). This was heat-cured at 170°C for 30 minutes to obtain a test piece. The adhesion was evaluated by carrying out a tensile shear test using the test piece. The test was carried out in accordance with JIS K 6850, and the maximum point stresses in the measurement environments of -40°C, 23°C, and 80°C were compared.

<T-type peel test>
The resin composition was applied to one of two cold-rolled steel plates ("SPCC-SB" manufactured by TP Giken Co., Ltd., 0.5 mm x 25 mm x 200 mm), glass beads ("J-80" manufactured by Potters Ballotini Co., Ltd.) were added as spacers, and the other SPCC-SB was attached (adhesion area: 25 mm x 150 mm). This was heat-cured at 170°C for 30 minutes to obtain a test piece. The test piece was used to evaluate adhesion by a T-peel test. The test was performed according to JIS K 6854-3, and the average stresses in the measurement environments of -40°C, 23°C, and 80°C were compared.

Observation of phase separation structure
A cross section of the cured resin was prepared using an ultramicrotome, and the phase separation structure was observed. The observation was performed using a scanning electron microscope (SEM) and an atomic force microscope (AFM). The presence or absence of a phase separation structure in the cured product can be confirmed by SEM observation. When the cured product has a phase separation structure and the structure forms a sea-island structure, the particle size of the island part was measured. In addition, the average particle size was calculated by randomly extracting 50 island parts from the island parts within a field of view of 200 μm × 260 μm, measuring the particle size, and determining the average particle size. In addition, the relative hardness distribution of the sea part and the island part can be confirmed by AFM observation.

(SEM)
Model used: JEOL JSM-7800F,
Acceleration voltage: 5 kV

(AFM)
Model used: Bruker AXS NANO Scope (R) IIIa
Measurement mode: DFM
Cantilever: Si-DF20
Measurement image type: Topographic image, phase image

The materials used in the table are as follows:
E-850S: Bisphenol A type epoxy resin (manufactured by DIC Corporation, epoxy equivalent 188 g/eq)
_CaCO3 : Light calcium carbonate (Omi Chemical Industry Co., Ltd.)
DICY: Dicyandiamide ("DICY7" manufactured by Mitsubishi Chemical Corporation)
DCMU: 3-(3,4-dichlorophenyl)-1,1-dimethylurea ("B-605-IM" manufactured by DIC Corporation)

As shown in Examples 3 to 6, the present invention shows that all of the compositions have high elongation in tensile tests and excellent adhesion over a wide temperature range.

The epoxy resin of the present invention can provide a flexible cured product that has both a high elongation rate assuming elastic deformation and high adhesion that can withstand the thermal expansion difference of the substrate. In particular, the resin composition obtained from the epoxy resin A and the epoxy resin B of the present invention has a phase separation structure after curing that balances the adhesiveness and stress relaxation ability of the cured product, and is therefore suitable for use in adhesives for structural materials and advanced electronic materials such as semiconductor sealing materials and insulating layers for multilayer printed circuit boards.

Claims (16)

The following general formula (1)

[In formula (1), each Ar is independently a structure having an unsubstituted or substituted aromatic ring,
X is a structural unit represented by the following general formula (2), and Y is a structural unit represented by the following general formula (3):

[In the formulas (2) and (3), Ar is the same as defined above,
R ₁ and R ₂ each independently represent a hydrogen atom, a methyl group, or an ethyl group;
R' is a divalent hydrocarbon group having 2 to 12 carbon atoms;
R ₃ , R ₄ , R ₇ and R ₈ each independently represent a hydroxyl group, a glycidyl ether group or a 2-methylglycidyl ether group;
R ₅ , R ₆ , R ₉ , and R ₁₀ each independently represent a hydrogen atom or a methyl group;
n1 is an integer from 4 to 16,
n2 is the average number of repeating units and is from 2 to 30.
R ₁₁ and R ₁₂ each independently represent a glycidyl ether group or a 2-methylglycidyl ether group;
R ₁₃ and R ₁₄ each independently represent a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group;
R ₁₅ and R ₁₆ each represent a hydrogen atom or a methyl group;
p1, p2, and q are the average values of the repetitions,
p1 and p2 each independently represent 0 to 5;
and q is 0.5 to 5. However, the bond between X represented by the general formula (2) and Y represented by the general formula (3) may be random or block, and the total numbers of the structural units X and Y present in one molecule are m1 and m2, respectively.
An epoxy resin represented by the formula:
Epoxy resin (a1) in which 1≦m1≦25 and 1≦m2≦25; or
An epoxy resin (A) having an epoxy equivalent of 500 to 10,000 g/eq, comprising, as essential components, an epoxy resin (a2) satisfying 1≦m1≦25 and m2=0, and an epoxy resin (a3) satisfying m1=0 and 1≦m2≦25;
An epoxy resin (B) having an epoxy equivalent of 100 to 300 g/eq;
An epoxy resin composition comprising: Ar in the general formulas (1) to (3) is each independently represented by the following structural formula (4):

...(4)
(The aromatic ring in formula (4) may be substituted or unsubstituted, and * represents a point of attachment.)
2. The epoxy resin composition according to claim 1, wherein the epoxy resin composition is any one of the following: 3. The epoxy resin composition according to claim 1, wherein n1 in the general formula (2) is 6 to 12, R ₃ and R ₄ are hydroxyl groups, and R ₅ and R ₆ are hydrogen atoms. The epoxy resin composition according to any one of claims 1 to 3, wherein, in the general formula (3), R' is a divalent hydrocarbon group having 2 to 6 carbon atoms, _R7 and _R8 are hydroxyl groups, and _R9 and _R10 are hydrogen atoms. The epoxy resin composition according to any one of claims 1 to 4, wherein the epoxy equivalent of the epoxy resin (A) is in the range of 800 to 5000 g/eq. 6. The epoxy resin composition according to claim 1, wherein, in formula (1), Ar further has a glycidyl ether group and/or a 2-methylglycidyl ether group .
The epoxy resin composition according to any one of claims 1 to 6, wherein the mass ratio (A):(B) of the epoxy resin (A) to the epoxy resin (B) is 90:10 to 10:90. The epoxy resin composition according to any one of claims 1 to 7, further comprising a curing agent (C). The epoxy resin composition according to any one of claims 1 to 8, which is an adhesive. A cured product of the epoxy resin composition according to any one of claims 1 to 9. the cured product has a phase-separated structure consisting of resin particles having an average particle size of 10 nm to 100 μm and a matrix surrounding the resin particles,
The cured product according to claim 10 , wherein the resin particles contain a cured product of the epoxy resin (A), and the matrix contains a cured product of the epoxy resin (B). the cured product has a phase-separated structure consisting of resin particles having an average particle size of 10 nm to 100 μm and a matrix surrounding the resin particles,
The cured product according to claim 10 , wherein the resin particles contain a cured product of the epoxy resin (B), and the matrix contains a cured product of the epoxy resin (A). A laminate formed by laminating a substrate and the cured product according to any one of claims 10 to 12. The laminate according to claim 13, which is formed by laminating in the order of a first substrate, a layer of the cured product according to any one of claims 10 to 12, and a second substrate. The laminate according to claim 14, wherein the first substrate is a substrate made of a metal or a metal oxide, and the second substrate is a substrate made of a plastic. The following general formula (5)

In formula (5), each Ar is independently a structure having an unsubstituted or substituted aromatic ring,
X is a structural unit represented by the following general formula (2), and Y is a structural unit represented by the following general formula (3):

[In the formulas (2) and (3), Ar is the same as defined above,
R ₁ and R ₂ each independently represent a hydrogen atom, a methyl group, or an ethyl group;
R' is a divalent hydrocarbon group having 2 to 12 carbon atoms;
R ₃ , R ₄ , R ₇ and R ₈ each independently represent a hydroxyl group, a glycidyl ether group or a 2-methylglycidyl ether group;
R ₅ , R ₆ , R ₉ , and R ₁₀ each independently represent a hydrogen atom or a methyl group;
n1 is an integer from 4 to 16,
n2 is the average number of repeating units and is from 2 to 30.
R ₁₁ and R ₁₂ each independently represent a glycidyl ether group or a 2-methylglycidyl ether group;
R ₁₃ and R ₁₄ each independently represent a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group;
R ₁₅ and R ₁₆ each represent a hydrogen atom or a methyl group;
p1, p2, and q are the average values of the repetitions,
p1 and p2 each independently represent 0 to 5;
and q is 0.5 to 5. However, the bond between X represented by the general formula (2) and Y represented by the general formula (3) may be random or block, and the total numbers of the structural units X and Y present in one molecule are m1 and m2, respectively.
An epoxy resin represented by the formula:
An epoxy resin characterized in that 1≦m1≦25 and 1≦m2≦25, and that the epoxy equivalent is 500 to 10,000 g/eq.