JP2014196431A - Epoxy resin, epoxy resin composition and hardened material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin which has flexibility and excellent low water absorption and strength.SOLUTION: An epoxy resin has chemical structures of formula (1) and (2) in the principal chain: (1) a chemical structure of hexamethylene diol with the terminal hydrogen removed; (2) a chemical structure of bisphenol with the terminal hydrogen removed.

Description

The present invention relates to an epoxy resin excellent in balance of flexibility, low water absorption and strength. The present invention also relates to an epoxy resin composition containing this epoxy resin and a curing agent, and a cured product obtained by curing the epoxy resin composition.

Epoxy resins are excellent in heat resistance, adhesiveness, water resistance, mechanical strength, and electrical properties, so they can be used in various fields such as adhesives, paints, civil engineering and building materials, and insulating materials for electrical and electronic parts. It is used. In particular, in the electric / electronic field, it is widely used in insulating casting materials, laminated materials, sealing materials and the like. In recent years, electrical and electronic parts have been miniaturized, refined, and enhanced in performance, and further multilayering, higher density, thinner thickness, lighter weight and improved reliability and molding processability are required. .

In particular, with the widespread use of mobile devices and the like, in the liquid sealing material and flexible printed wiring boards used for semiconductor packaging materials, the epoxy resin excellent in flexibility that can impart appropriate flexibility to the cured epoxy resin Therefore, various flexible epoxy resins corresponding to the demand have been developed.

For example, Patent Document 1 discloses a flexible epoxy resin obtained by reacting a bifunctional epoxy resin obtained from a dihydric alcohol with a dihydric phenol.

Japanese Patent Laid-Open No. 2005-320477

  According to detailed examinations by the present inventors, an epoxy produced by reacting 1,6 hexanediol diglycidyl ether and bisphenol A type epoxy resin or bisphenol F type epoxy resin produced in Patent Document 1. While the resin has flexibility, it has an aliphatic skeleton with a small molecular weight in the main chain, so that it has a problem that the water absorption is remarkably deteriorated (high water absorption) compared to conventional general-purpose epoxy resins. It was issued. Further, a problem has been found that these epoxy resins have insufficient strength necessary for improving crack resistance.

  The present invention has been made for the purpose of solving the above problems, and has an excellent balance of flexibility, low water absorption and strength, and is applicable to various fields that require high reliability, and the epoxy resin. An epoxy resin composition containing a resin and a cured product obtained by curing the epoxy resin composition are provided.

  As a result of intensive studies by the present inventors to solve the above problems, an epoxy resin having a 1,6-hexylene structure and a chemical structure derived from bisphenol having a total carbon number within a specific range in the chemical structure of the epoxy resin. Has been found to be excellent in the balance of flexibility, low water absorption and strength. That is, the gist of the present invention resides in the following [1] to [17].

[1] An epoxy resin represented by the following formula (1).

(In the above formula (1), A includes at least the chemical structure represented by the above formula (2) and the chemical structure represented by the formula (3), and R is represented by a hydrogen atom or the above formula (4). N is a number from 1 to 250. In the above formula (3), X is a direct bond, a divalent hydrocarbon group having 1 to 20 carbon atoms, -O-, -S-, -SO. ₂ and -CO-, and R ^{1 to} R ⁸ may be different from each other, and are a group selected from a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, or a halogen element. The total number of carbon atoms contained in the chemical structure represented by 3) is 16 or more and 50 or less.)

[2] The epoxy resin according to [1], wherein the chemical structure represented by the formula (2) is included in the formula (1) in an amount of 1 to 99 mol% with respect to the total number of moles of A.

[3] As A in the formula (1), the molar ratio between the chemical structure represented by the formula (2) and the chemical structure represented by the formula (3) is 1/99 to 99/1. The epoxy resin according to [1] or [2].

[4] An epoxy resin obtained by reacting a bifunctional epoxy resin represented by the following formula (5) with a divalent hydroxyl group-containing compound represented by the following formula (6).

(In the above formulas (5) and (6), A ′ has at least the chemical structure represented by the above formula (2 ′) and the chemical structure represented by the above formula (3 ′). , M is an average value of the number of repetitions and is 0 or more and 6. or less In the above formula (3 ′), X ′ is a direct bond, a divalent hydrocarbon group having 1 to 20 carbon atoms, —O—, —S. —, —SO ₂ — and —CO—, R ′ ^{1 to} R ′ ⁸ may be different from each other, and are selected from a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, or a halogen element. And the total number of carbon atoms contained in the chemical structure represented by the formula (3 ′) is 16 or more and 50 or less.)

[5] In the above formulas (5) and (6), the chemical structure represented by the formula (2 ′) is included in an amount of 1 to 99 mol% based on the total number of moles of A ′. Epoxy resin.

[6] As A ′ in the formula (5) and the formula (6), the molar ratio between the chemical structure represented by the formula (2 ′) and the chemical structure represented by the formula (3 ′) is The epoxy resin according to [4] or [5], which is 1/99 to 99/1.

[7] The epoxy resin according to any one of [1] to [6], wherein an epoxy equivalent is 200 g / equivalent or more and 30,000 g / equivalent or less.

[8] The epoxy resin according to any one of [1] to [7], which has a weight average molecular weight of 1,000 to 100,000.

[9] An epoxy resin composition comprising the epoxy resin according to any one of [1] to [8] and a curing agent.

[10] The epoxy resin composition according to [9], including 0.01 to 100 parts by weight of a curing agent with respect to 100 parts by weight of the epoxy resin.

[11] The curing agent is at least one selected from the group consisting of a phenolic curing agent, an amide curing agent, an amine curing agent, an imidazole, an acid anhydride curing agent, and an organic phosphine. ] Or the epoxy resin composition according to [10].

[12] A sealing material for an electric / electronic circuit comprising the epoxy resin composition according to any one of [9] to [11].

[13] A laminate for an electric / electronic circuit comprising the epoxy resin composition according to any one of [9] to [11].

[14] An optical member comprising the epoxy resin composition according to any one of [9] to [11].

[15] An adhesive comprising the epoxy resin composition according to any one of [9] to [11].

[16] A paint comprising the epoxy resin composition according to any one of [9] to [11].

[17] A cured product obtained by curing the epoxy resin composition according to any one of [9] to [11].

  The epoxy resin of this invention and the epoxy resin composition containing the same give the hardened | cured material excellent in flexibility. In addition, since the glass transition temperature of the epoxy resin of the present invention and a cured product obtained using the epoxy resin is relatively low and can maintain high flexibility even under low temperature use conditions, an adhesive, a paint, It can be applied to various fields such as civil engineering building materials and insulating materials for electric / electronic parts, and is particularly useful as a sealing material, laminated material, insulating casting, etc. in the electric / electronic field. In addition, this epoxy resin composition is excellent in low water absorption and strength, and has improved crack resistance of the cured product, so that it is a semiconductor sealing material, underfill material, 3D-LSI interchip fill, die bonding material Adhesives such as film adhesives, liquid adhesives, multilayer printed wiring boards, laminates for electrical and electronic circuits such as capacitors, insulation sheets, prepregs, heat dissipation boards, and adhesion improvers for electrical and electronic applications. It can use suitably in the use as a flexibility provision material.

  Embodiments of the present invention will be described in detail below, but the following description is an example of the embodiments of the present invention, and the present invention is limited to the following description unless it exceeds the gist. is not. In addition, when using the expression “to” in the present specification, it is used as an expression including numerical values or physical property values before and after the expression.

〔Epoxy resin〕
The epoxy resin of this invention is represented by following formula (1).

(In the above formula (1), A includes at least the chemical structure represented by the above formula (2) and the chemical structure represented by the formula (3), and R is represented by a hydrogen atom or the above formula (4). N is a number from 1 to 250. In the above formula (3), X is a direct bond, a divalent hydrocarbon group having 1 to 20 carbon atoms, -O-, -S-, -SO. ₂ and -CO-, and R ^{1 to} R ⁸ may be different from each other, and are a group selected from a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, or a halogen element. The total number of carbon atoms contained in the chemical structure represented by 3) is 16 or more and 50 or less.)

  The epoxy resin of this invention has the remarkable effect that it is excellent in the balance of flexibility, low water absorption, and intensity | strength. It is presumed that the epoxy resin of the present invention has such an effect for the following reason. About flexibility, it is estimated that it is based on the softness | flexibility of the chemical structure represented by said Formula (2). In addition, the strength is bulky due to the large number of total carbon atoms in the chemical structure represented by the formula (3), resulting in a structure having strength, and the water absorption is also represented by the formula represented by the formula (3). Since the total number of carbon atoms in the structure is large, it is estimated that in the epoxy resin represented by the formula (1), the ratio of secondary hydroxyl groups contributing to water absorption to the entire molecular structure is relatively low. The

<Chemical structure>
In the formula (1), A necessarily includes the chemical structure represented by the formula (3). Here, R ^{1 to} R ⁸ in the formula (3) may be different from each other and are a group selected from a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, or a halogen element. Among these, examples of the hydrocarbon group having 1 to 12 carbon atoms include the following. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, cyclopentyl group, n-hexyl group, isohexyl group, cyclohexyl group, n-heptyl group, cycloheptyl group, methylcyclohexyl group, n-octyl group, cyclooctyl group, n-nonyl group, 3,3,5-trimethylcyclohexyl group, n- Decyl group, cyclodecyl group, n-undecyl group, n-dodecyl group, cyclododecyl group, phenyl group, benzyl group, methylbenzyl group, dimethylbenzyl group, trimethylbenzyl group, naphthylmethyl group, phenethyl group, 2-phenylisopropyl group Etc. Among these, an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group is preferable. Of the halogen elements, fluorine and bromine are preferred.

X in the formula (3) represents a direct bond, a divalent hydrocarbon group having 1 to 20 carbon atoms, a divalent linkage selected from —O—, —S—, —SO ₂ — and —CO—. It is a group.

Here, examples of the divalent hydrocarbon group of the formula (3) X carbon atoms from 1 to 20 in, for _{example, -CH 2 -, - CH (} CH 3) -, - C (CH 3) 2 -, —C (CF ₃ ) ₂ —, —CHPh— (in the present invention, Ph is a phenyl group), —C (CH ₃ ) Ph—, —CPh ₂ —, 9,9-fluorenylene group, 1, 1-cyclopropylene group, 1,1-cyclobutylene group, 1,1-cyclopentylene group, 1,1-cyclohexylene group, 3,3,5-trimethyl-1,1-cyclohexylene group, 1,1 -Cyclododecylene group, 1,2-ethylene group, 1,2-cyclopropylene group, 1,2-cyclobutylene group, 1,2-cyclopentylene group, 1,2-cyclohexylene group, 1,2-phenylene group 1,3-propylene group, 1,3-cyclo Tylene group, 1,3-cyclopentylene group, 1,3-cyclohexylene group, 1,3-phenylene group, 1,4-butylene group, 1,4-cyclohexylene group, 1,4-phenylene group, etc. Can be mentioned.

  Among these linking groups in X of the formula (3), 9,9-fluorenylene group, 1,1-cyclohexylene group, 3,3,5-trimethylcyclohexylene group, 1,1-cyclododecylene group, etc. Those having a large molecular weight and a sterically bulky substituent are more preferred. Since the molecular weight per unit unit is larger than that of ordinary epoxy resins, the proportion of secondary hydroxyl groups that cause water absorption in the entire molecular structure is relatively low, and the steric hindrance can inhibit the access of water molecules. It is considered a thing.

  In the formula (1), R is a hydrogen atom or a group (epoxy group) represented by the formula (4). That is, in the formula (1), R represents a terminal structure, both ends may be a hydrogen atom or an epoxy group of the formula (4), and only one end is a hydrogen atom or an epoxy of the formula (4) It may be a group. However, since the formula (1) is an epoxy resin, R in the formula (1) includes at least an epoxy group. The epoxy resin of the present invention is usually a mixture of molecules having these ends or molecules having different repeating numbers n described below.

  In said Formula (1), n is a repeating number and is an average value. The range of the value is 1 or more from the viewpoint of flexibility, and 250 or less from the viewpoint of handleability of the epoxy resin. From the viewpoint of making these better, it is preferably 1.1 or more, more preferably 1.3 or more, on the other hand, preferably 100 or less, more preferably 70 or less, and still more preferably. 50 or less. The n number can be calculated from the number average molecular weight (Mn) obtained by the gel permeation chromatography method (GPC method). Specific examples of the GPC method for determining the number average molecular weight will be described in the examples below.

The total number of carbon atoms contained in the chemical structure represented by the formula (3) is 16 or more and 50 or less. When the total number of carbon atoms contained in the chemical structure represented by the formula (3) is not less than the lower limit, the entire chemical structure represented by the formula (3) has a certain molecular weight and a sterically bulky structure. As a result, the proportion of the secondary hydroxyl group that causes water absorption in the entire epoxy resin is relatively low, and steric hindrance can inhibit the access of water molecules, resulting in low water absorption. . On the other hand, flexibility can be maintained by being below the upper limit. From the viewpoint of obtaining low water absorption, the total number of carbon atoms is preferably 18 or more, more preferably 20 or more, and still more preferably 22 or more. On the other hand, from the viewpoint of maintaining appropriate flexibility, it is preferably 40 or less, and preferably 30 or less.

  In the formula (1), A includes at least the chemical structure represented by the formula (2) and the chemical structure represented by (3), and has a good balance between flexibility, water absorption, and strength. From the viewpoint of, the proportion of the chemical structure represented by the formula (2) in A is 1 to 99 mol% with respect to the total number of moles of A, and the proportion of the chemical structure represented by the formula (3) is 1 to 99 mol % Is preferred. From the viewpoint of improving these effects, the proportion of the chemical structure represented by formula (2) in A is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 30 mol%. On the other hand, it is preferably 90 mol% or less, more preferably 80 mol% or less, and particularly preferably 70 mol% or less. It is preferable for the ratio of formula (2) in A to be in the above-mentioned range because it tends to have low water absorption and high strength while having flexibility.

  The epoxy resin of the present invention has the effect of flexibility due to the chemical structure represented by the formula (2), and the effect of low water absorption and strength due to the chemical structure represented by the formula (3). Have gained. As A in the formula (1), the molar ratio between the chemical structure represented by the formula (2) and the chemical structure represented by the formula (3) ([the chemical structure represented by the formula (2) The number of moles] / [number of moles of the chemical structure represented by the formula (3)]) is preferably 1/99 or more, and preferably 10/90 or more, from the viewpoint of flexibility. On the other hand, from the viewpoint of low water absorption and strength, it is preferably 99/1 or less, more preferably 90/10 or less, and further preferably 80/20 or less. preferable.

  In the formula (1), A may include other chemical structures other than the chemical structure represented by the formula (2) and the chemical structure represented by the formula (3). Other chemical structures are not particularly limited, but benzenediols such as hydroquinone, methylhydroquinone, dibutylhydroquinone, dihydroanthrahydroquinone, resorcin, and methylresorcin (herein, “benzenediols are compounds having one benzene ring” A compound in which two hydroxyl groups are directly bonded to the benzene ring.); Dihydroxydiphenyl ethers such as dihydroxydiphenyl ether; thiodiphenols such as thiodiphenol; dihydroxynaphthalenes such as dihydroxynaphthalene; dihydroxystilbene Dialkyl stilbenes such as ethylene glycol, trimethylene glycol, propylene glycol, butylene glycol, etc. Obtained by epoxidizing a structure derived from a divalent hydroxyl group-containing compound such as polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, and these divalent hydroxyl group-containing compounds. The chemical structure derived from the bifunctional epoxy resin obtained, etc. These chemical structures are represented by the bifunctional epoxy resin represented by the formula (5) and / or the formula (6) in the production method described later. In addition to the divalent hydroxyl group-containing compound, the above raw materials can be used in combination, and the proportion of the other chemical structure in A in the formula (1) is usually 30 mol% or less, preferably 15 mol. % Or less, more preferably 5 mol% or less.

In addition, in the epoxy resin of the present invention, the chemical structure represented by the formula (2), the chemical structure represented by the formula (3), and the ratio of other chemical structures are items of the epoxy resin production method described later. As will be described in FIG. 4, it can be controlled by the ratio of the raw materials. For this reason, in the epoxy resin of this invention, the ratio of the chemical structure contained in each of the bifunctional epoxy resin used as a raw material and the bivalent hydroxyl-containing compound is the chemical structure contained in the epoxy resin of this invention as it is. It shall be regarded as a percentage.

<Epoxy equivalent>
The epoxy equivalent of the epoxy resin of the present invention is preferably not less than 200 g / equivalent, more preferably not less than 300 g / equivalent, still more preferably not less than 400 g / equivalent, while preferably not more than 30,000 g / equivalent, More preferably, it is 25,000 equivalent or less, More preferably, it is 20,000 g / equivalent or less, Most preferably, it is 15,000 g / equivalent or less. When the epoxy equivalent is not less than the above lower limit value, it is preferable from the viewpoint of flexibility, and when it is not more than the above upper limit value, the handling of the epoxy resin tends to be good. In the present invention, “epoxy equivalent” is defined as “mass of an epoxy resin containing one equivalent of an epoxy group” and is defined in JIS.
It can be measured according to K7236.

<Weight average molecular weight>
The weight average molecular weight (Mw) of the epoxy resin of the present invention is preferably 1,000 or more, more preferably 1,500 or more, on the other hand, preferably 100,000 or less, more preferably 50,000 or less. When the weight average molecular weight is not less than the above lower limit, it is preferable from the viewpoint of flexibility, and when it is not more than the above upper limit, the handling of the epoxy resin tends to be good. In addition, the weight average molecular weight and number average molecular weight of an epoxy resin can be measured by the gel permeation chromatography method (GPC method). An example of a more detailed method will be described in the examples described later. In the present invention, those having a weight average molecular weight of less than 10,000 are sometimes referred to as “low molecular weight epoxy resins”, and those having a weight average molecular weight of 10,000 or more are referred to as “high molecular weight epoxy resins”. Sometimes called.

<Glass transition temperature (Tg)>
Since the epoxy resin of the present invention has flexibility, it is useful as a flexibility imparting material. The flexibility-imparting material is preferably in a region where the glass transition temperature (Tg) is low to some extent, because flexibility can be maintained even under use conditions at low temperatures. From this viewpoint, in the case of a low molecular weight epoxy resin, the glass transition temperature is preferably −40 ° C. or higher, more preferably −28 ° C. or higher, and preferably 5 ° C. or lower, 0 ° C. The following is more preferable. From the same viewpoint, in the case of a high molecular weight epoxy resin, it is preferably 10 ° C. or higher, more preferably 20 ° C. or higher, and preferably 100 ° C. or lower, and 95 ° C. or lower. Is more preferable. The glass transition temperature can be determined by a DSC method (differential scanning calorimeter). More specifically, it can be determined by the method described in the Examples below.

<Method for producing epoxy resin>
The epoxy resin of the present invention can be obtained by a two-stage method in which a bifunctional epoxy resin and a divalent hydroxyl group-containing compound are reacted. It can also be obtained by a one-step method in which two or more kinds of divalent hydroxyl group-containing compounds and epichlorohydrin are directly reacted. However, it is preferable to use the two-step method because various epoxy resins from low molecular weight to high molecular weight can be obtained more easily than the one-step method by the two-step method.

[Production method by two-stage method]
An epoxy resin according to another embodiment of the present invention is obtained by reacting at least a bifunctional epoxy resin represented by the formula (5) and a divalent hydroxyl group-containing compound represented by the formula (6). It is characterized by that.

(In the above formulas (5) and (6), A ′ has at least the chemical structure represented by the above formula (2 ′) and the chemical structure represented by the above formula (3 ′). , M is an average value of the number of repetitions and is 0 or more and 6. or less In the above formula (3 ′), X ′ is a direct bond, a divalent hydrocarbon group having 1 to 20 carbon atoms, —O—, —S. —, —SO ₂ — and —CO—, R ′ ^{1 to} R ′ ⁸ may be different from each other, and are selected from a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, or a halogen element. And the total number of carbon atoms contained in the chemical structure represented by the formula (3 ′) is 16 or more and 50 or less.)

(Bifunctional epoxy resin)
The bifunctional epoxy resin used in the production of the epoxy resin of the present invention is an epoxy resin represented by the above formula (5). For example, a divalent hydroxyl group-containing compound represented by the above formula (6) will be described later. An epoxy resin obtained by condensing with epihalohydrin by a method similar to the one-step method.

  In the formula (5), A ′ may or may not contain the chemical structure represented by the formula (2 ′). However, when A ′ in the formula (5) does not include the chemical structure represented by the formula (2 ′), A ′ in the formula (6) is the chemistry represented by the formula (2 ′). It always includes the structure. In the formula (5), A ′ may or may not contain the chemical structure represented by the formula (3 ′). However, when A ′ in the formula (5) does not include the chemical structure represented by the formula (3 ′), A ′ in the formula (6) is the chemistry represented by the formula (3 ′). It always includes the structure. When A ′ in the formula (5) does not include the chemical structure represented by the formula (2 ′) and the chemical structure represented by the formula (3 ′), the A ′ is a known arbitrary one. The chemical structure of can be introduced.

For the definition and preferred R ¹ ′ to R ⁸ ′ in the formula (3 ′), the formula (3)
Are the same as R ^{1 to} R ⁸ . Further, the definition and preferred ones of X ′ in the formula (3 ′) are the same as X in the formula (3).

  M in said Formula (5) is an average value of the number of repetitions, and is 0 or more and 6 or less.

(Divalent hydroxyl group-containing compound)
The divalent hydroxyl group-containing compound used for the production of the epoxy resin of the present invention is a divalent hydroxyl group-containing compound represented by the formula (6).

  In the formula (6), A ′ may or may not contain the chemical structure represented by the formula (2 ′). However, when A ′ in the formula (6) does not include a chemical structure represented by the formula (2 ′), A ′ in the formula (5) is a chemistry represented by the formula (2 ′). It always includes the structure. In the formula (6), A ′ may or may not contain the chemical structure represented by the formula (3 ′). However, when A ′ in the formula (6) does not include the chemical structure represented by the formula (3 ′), A ′ in the formula (5) is the chemistry represented by the formula (3 ′). It always includes the structure. When A ′ in the formula (6) does not include the chemical structure represented by the formula (2 ′) and the chemical structure represented by the formula (3 ′), the A ′ is a known arbitrary one. The chemical structure of can be introduced.

  That is, the epoxy resin produced by the two-step method always includes the chemical structure represented by the formula (2 ′). As long as this is satisfied, the chemical structure of the formula (2) is 2 It may be contained in either the functional epoxy resin or the divalent hydroxyl group-containing compound, and the ratio of the chemical structure is not limited. Similarly, the epoxy resin produced by the two-stage method always includes the chemical structure represented by the formula (3 ′), and as long as this is satisfied, the chemical structure of the formula (3) It may be contained in any of a bifunctional epoxy resin and a divalent hydroxyl group-containing compound, and the ratio of its chemical structure is not limited.

  The bifunctional epoxy resin or divalent hydroxyl group-containing compound used for the production of the epoxy resin of the present invention has a chemical structure represented by the formula (2 ′) from the viewpoint of balance between flexibility, low water absorption, and strength. However, it is preferable that 1-99 mol% is contained with respect to the total number of moles of A ′ in the formulas (5) and (6). From the viewpoint of further enhancing this effect, the proportion of the formula (2) is preferably 10 mol% or more, more preferably 20 mol% or more, still more preferably 30 mol% or more, while preferably 90 mol% or less. More preferably, it is 80 mol% or less, Most preferably, it is 70 mol% or less.

  In the formula (5) and the formula (6), A ′ includes at least the chemical structure represented by the formula (2 ′) and the chemical structure represented by (3 ′), and has flexibility and low water absorption. From the viewpoint of balance with strength, the proportion of the chemical structure represented by the formula (2 ′) in the whole A ′ of the formulas (5) and (6) is 1 to 99 mol% with respect to the number of moles of the whole A ′. The ratio of the bisphenol skeleton represented by the formula (3 ′) is 1 to 99 mol%. From the viewpoint of further enhancing this effect, the proportion of the chemical structure represented by the formula (2 ′) in A ′ is preferably 10 mol% or more, more preferably 20 mol% or more, and further preferably 30 mol% or more. On the other hand, it is preferably 90 mol% or less, more preferably 80 mol% or less, particularly preferably 70 mol% or less.

The epoxy resin of the present invention has a flexible effect due to the chemical structure represented by the formula (2 ′), and has a low water absorption and strength due to the chemical structure represented by the formula (3 ′). Has the effect of. Therefore, as A ′ in the formula (5) and the formula (6), a molar ratio of the chemical structure represented by the formula (2 ′) and the chemical structure represented by the formula (3 ′) ( [Number of moles of chemical structure represented by formula (2 ′) / [number of moles of chemical structure represented by formula (3 ′)])
It is preferably 1/99 or more, preferably 10/90 or more, more preferably 20/80 or more. On the other hand, from the viewpoint of low water absorption and strength, it is 99/1 or less. Preferably, it is 90/10 or less, more preferably 80/20 or less.

(catalyst)
A catalyst may be used for the synthesis of the epoxy resin of the present invention, and any catalyst may be used as long as it has a catalytic ability to promote a reaction between an epoxy group and a phenolic hydroxyl group, an alcoholic hydroxyl group or a carboxyl group. Something like that. For example, alkali metal compounds, organic phosphorus compounds, tertiary amines, quaternary ammonium salts, cyclic amines, imidazoles and the like can be mentioned.

  Among the catalysts mentioned above, quaternary ammonium salts are preferred. Moreover, a catalyst can use only 1 type and can also be used in combination of 2 or more type. The usage-amount of a catalyst is 0.001-1 weight% normally in reaction solid content.

(solvent)
The epoxy resin of the present invention may use a reaction solvent in the step of the synthesis reaction at the time of production, and any solvent may be used as long as it dissolves the epoxy resin. Examples include aromatic solvents, ketone solvents, amide solvents, glycol ether solvents, and the like.

  Specific examples of the aromatic solvent include benzene, toluene, xylene and the like. Specific examples of the ketone solvent include acetone, methyl ethyl ketone (hereinafter sometimes referred to as “MEK”), methyl isobutyl ketone (hereinafter sometimes referred to as “MIBK”), 2-heptanone, 4 -Heptanone, 2-octanone, cyclohexanone, acetylacetone and the like. Specific examples of the amide solvent include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, 2-pyrrolidone, N-methylpyrrolidone and the like. Specific examples of the glycol ether solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol. Examples include mono-n-butyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol mono-n-butyl ether, propylene glycol monomethyl ether acetate, and dioxane. These solvents may be used alone or in combination of two or more.

(solvent)
The solid concentration in the synthesis reaction during the production of the epoxy resin is preferably 35 to 95% by weight. For this reason, you may use the organic compound similar to what was mentioned in the above-mentioned solvent as a solvent for dilution. For example, when a highly viscous product is produced during the reaction, the reaction can be continued by adding an additional solvent. After completion of the reaction, the solvent can be removed or further added as necessary. In the present invention, the term “solvent” and the term “solvent” are distinguished from each other depending on the form of use, but the same type or different types may be used.

(Reaction conditions)
In the production of the epoxy resin, the polymerization reaction between the bifunctional epoxy resin and the divalent hydroxyl group-containing compound is carried out at a reaction temperature at which the catalyst used does not decompose. If the reaction temperature is too high, the produced epoxy resin may be deteriorated. Conversely, if the temperature is too low, the reaction may not proceed sufficiently. For these reasons, the reaction temperature is preferably 50 to 230 ° C, more preferably 120 to 200 ° C. Moreover, reaction time is 1 to 12 hours normally, Preferably it is 3 to 10 hours. When using a low boiling point solvent such as acetone or methyl ethyl ketone, the reaction temperature can be ensured by carrying out the reaction under high pressure using an autoclave.

[Manufacturing by one-step method]
The epoxy resin of the present invention can also be produced by a one-step method. Specifically, the divalent hydroxyl group-containing compound represented by the formula (6) may be directly reacted with epichlorohydrin. However, as described above, among the epoxy resins of the present invention produced by the one-step method, those having a low molecular weight can be used as the bifunctional epoxy resin in the two-step method.

  When the epoxy resin of the present invention is produced by a one-step method, A ′ is a chemistry represented by formulas (2) and (3) in the divalent hydroxyl group-containing compound represented by formula (6) used as a raw material. Always include structure. For the same reason as described in the two-stage method, the proportion of the formula (2) with respect to the entire A ′ is preferably 10 mol% or more, more preferably 20 mol% or more, and further preferably 30 mol% or more. Moreover, 90 mol% or less is preferable, 80 mol% or less is more preferable, and 70 mol% or less is still more preferable.

  The amount of epihalohydrin used in the reaction is usually 0.8 to 20 molar equivalents, more preferably 0.9 to 15 molar equivalents, and still more preferably 1.0 to 10 molar equivalents per molar equivalent of hydroxyl group of the divalent hydroxyl group-containing compound. An amount corresponding to the molar equivalent is used, and the divalent hydroxyl group-containing compound is dissolved in epihalohydrin to obtain a uniform solution. It is preferable that the amount of the epihalohydrin is not less than the above lower limit value because the molecular weight is not increased more than necessary, the reaction is easily controlled, and an appropriate melt viscosity can be obtained. On the other hand, when the amount of epihalohydrin is not more than the above upper limit value, production efficiency tends to be improved, which is preferable. As epihalohydrin in this reaction, epichlorohydrin and / or epibromohydrin is usually used.

  Next, while stirring the solution, usually 0.5 to 2.0 molar equivalents, preferably 0.7 to 1.8 molar equivalents, more preferably, per 1 molar equivalent of hydroxyl groups of the divalent hydroxyl group-containing compound. An amount of alkali metal hydroxide corresponding to 0.9 to 1.6 molar equivalents is added as a solid or an aqueous solution and reacted. It is preferable that the amount of the alkali metal hydroxide is not less than the above lower limit value because it is possible to prevent the unreacted hydroxyl group and the generated epoxy resin from reacting to increase the molecular weight more than necessary. Moreover, it is preferable for the alkali metal hydroxide to be not more than the above upper limit value because the generation of impurities due to side reactions can be reduced. As the alkali metal hydroxide, sodium hydroxide and / or potassium hydroxide is usually used.

  This reaction can be carried out under normal pressure or reduced pressure, and the reaction temperature is usually 20 to 150 ° C., more preferably 30 to 120 ° C., more preferably 35 to 100 ° C. in the case of reaction under normal pressure, In the case of the reaction under reduced pressure, it is 20 to 100 ° C, more preferably 30 to 90 ° C, still more preferably 35 ° C to 80 ° C. It is preferable that the reaction temperature is equal to or higher than the lower limit because the reaction is likely to proceed. When the reaction temperature is not more than the above upper limit, side reactions are unlikely to proceed. In particular, when epichlorohydrin is used as the epihalohydrin, it is preferable because chlorine impurities can be easily reduced.

In the reaction, if necessary, the reaction liquid is azeotroped while maintaining a predetermined temperature, the condensate obtained by cooling the vaporized vapor is separated into oil and water, and the oil removed from the water is sent to the reaction system. Dehydrate by returning method. The addition of alkali metal hydroxide is preferably 0.5 to 8 hours, more preferably 1 to 7 hours, and still more preferably 1 to 6 hours, in order to suppress a rapid reaction, intermittently or continuously. Add it. It is preferable for the addition time to be equal to or more than the above lower limit value since the reaction can be prevented from proceeding rapidly and the reaction temperature can be easily controlled. On the other hand, when the addition time is equal to or shorter than the above upper limit value, it is preferable when epichlorohydrin is used as the epihalohydrin because chlorine impurities are not easily generated, and it is also preferable from the viewpoint of economy. The total reaction time is usually 1 to 15 hours. After completion of the reaction, the insoluble by-product salt is removed by filtration or removed by washing with water, and then the unreacted epihalohydrin is removed by distillation under reduced pressure to obtain the desired epoxy resin.

  In this reaction, quaternary ammonium salts such as tetramethylammonium chloride and tetraethylammonium bromide; tertiary amines such as benzyldimethylamine and 2,4,6-tris (dimethylaminomethyl) phenol; 2-ethyl Imidazoles such as -4-methylimidazole and 2-phenylimidazole; phosphonium salts such as ethyltriphenylphosphonium iodide; phosphines such as triphenylphosphine; acidic catalysts such as sulfuric acid, boron trifluoride ethyl ether, and tin tetrachloride A catalyst such as the above may be used.

  Furthermore, in this reaction, alcohols such as ethanol and isopropanol; ketones such as acetone and methyl ethyl ketone; ethers such as dioxane and ethylene glycol dimethyl ether; glycol ethers such as methoxypropanol; aprotic such as dimethyl sulfoxide and dimethylformamide An inert organic solvent such as a polar solvent may be used.

  Furthermore, when the amount of saponifiable halogen in the epoxy resin obtained as described above is too large, a purified epoxy resin having a sufficiently reduced amount of saponifiable halogen can be obtained by reprocessing. That is, the crude epoxy resin is redissolved in an inert organic solvent such as isopropyl alcohol, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, dioxane, methoxypropanol, dimethyl sulfoxide, and the alkali metal hydroxide is added as a solid or aqueous solution. The temperature is preferably 30 to 120 ° C, more preferably 40 to 110 ° C, still more preferably 50 to 100 ° C, preferably 0.1 to 15 hours, more preferably 0.3 to 12 hours, and still more preferably 0. After re-ringing reaction for 5 to 10 hours, excess alkali metal hydroxide or by-product salt is removed by a method such as washing with water, and the organic solvent is distilled off under reduced pressure and / or steam distillation. An epoxy resin with a reduced amount of decomposable halogen can be obtained. It is preferable for the reaction temperature to be within the above-mentioned range since the re-ring closure reaction will easily proceed. Moreover, it is preferable for the reaction temperature to be within the above range because the high molecular weight reaction can be easily controlled.

[Epoxy resin composition]
The epoxy resin composition of the present invention is an epoxy resin composition containing at least the above-described epoxy resin of the present invention and a curing agent. Moreover, the epoxy resin composition of this invention can mix | blend suitably another epoxy resin, another component, etc. as needed. The epoxy resin composition of the present invention is excellent in the balance of flexibility, low water absorption, and strength, and provides a cured product that sufficiently satisfies various physical properties required for various applications.

<Curing agent>
In the present invention, the curing agent means a substance that contributes to a crosslinking reaction and / or a chain extension reaction between epoxy groups of an epoxy resin. In the present invention, even if what is usually called a “curing accelerator” is a substance that contributes to a crosslinking reaction and / or chain extension reaction between epoxy groups of an epoxy resin, it is regarded as a curing agent. To do.

The content of the curing agent in the epoxy resin composition of the present invention is preferably 0.01 to 100 parts by weight with respect to 100 parts by weight of the epoxy resin of the present invention. Further, it is more preferably 80 parts by weight or less, and still more preferably 60 parts by weight or less.

  Moreover, in the epoxy resin composition of this invention, when other epoxy resin mentioned later is contained, Preferably content of a hardening | curing agent is 0.01-100 with respect to 100 weight part of all the epoxy resin components as solid content. Parts by weight. Further, it is more preferably 80 parts by weight or less, and still more preferably 60 parts by weight or less. In the present invention, the “solid content” means a component excluding a solvent, and includes not only a solid epoxy resin but also a semi-solid or viscous liquid material. The “total epoxy resin component” means the total of the epoxy resin of the present invention and other epoxy resins described later.

  There is no restriction | limiting in particular as a hardening | curing agent used for the epoxy resin composition of this invention, What is generally known as an epoxy resin hardening | curing agent can be used. Among these, phenol-based curing agents, amide-based curing agents, amine-based curing agents (excluding tertiary amines), imidazoles, acid anhydride-based curing agents, and organic phosphines are exemplified. Examples of phenolic curing agents, amide curing agents, amine curing agents (excluding tertiary amines), imidazoles, acid anhydride curing agents, organic phosphines, and other usable curing agents Give up.

[Phenolic curing agent]
It is preferable to use a phenol-based curing agent as the curing agent from the viewpoint of improving the handleability of the resulting epoxy resin composition and the heat resistance after curing. Specific examples of the phenolic curing agent include bisphenol A, bisphenol F, 4,4′-dihydroxydiphenylmethane, 4,4′-dihydroxydiphenyl ether, 1,4-bis (4-hydroxyphenoxy) benzene, 1,3-bis. (4-hydroxyphenoxy) benzene, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl 10- (2,5-dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide, phenol novolak, bisphenol A novolak, o-cresol novolak, m-cresol novolak, p-cresol Novo Lac, xylenol novolak, poly-p-hydroxystyrene, hydroquinone, resorcin, catechol, t-butylcatechol, t-butylhydroquinone, fluoroglycinol, pyrogallol, t-butyl pyrogallol, allylated pyrogallol, polyallylated pyrogallol, 1,2 , 4-Benzenetriol, 2,3,4-trihydroxybenzophenone, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,4-dihydroxynaphthalene, 2,5-dihydroxynaphthalene, 2,6-dihydride Examples include xinaphthalene, 2,7-dihydroxynaphthalene, 2,8-dihydroxynaphthalene, allylated or polyallylated dihydroxynaphthalene, allylated bisphenol A, allylated bisphenol F, allylated phenol novolak, allylated pyrogallol, etc. .

  The phenolic curing agents mentioned above may be used alone or in a combination of two or more in any combination and ratio. Moreover, when a hardening | curing agent is a phenol type hardening | curing agent, it is preferable to use so that it may become the range of 0.8-1.5 by the equivalent ratio of the functional group in a hardening | curing agent with respect to the epoxy group in an epoxy resin. Within this range, unreacted epoxy groups and functional groups of the curing agent are unlikely to remain, which is preferable.

[Amide-based curing agent]
It is preferable to use an amide-based curing agent as the curing agent from the viewpoint of improving heat resistance and the like. Examples of the amide-based curing agent include dicyandiamide and derivatives thereof, and polyamide resins.

  The amide type curing agents listed above may be used alone or in a combination of two or more in any combination and ratio. Moreover, it is preferable to use an amide type hardening | curing agent in 0.1-20 weight% with respect to the sum total of all the epoxy resin components and amide type hardening | curing agents as solid content in an epoxy resin composition.

[Amine curing agent]
It is preferable to use an amine-based curing agent (excluding tertiary amine) as the curing agent from the viewpoint of improving heat resistance and the like. Examples of amine-based curing agents include aliphatic amines, polyether amines, alicyclic amines, aromatic amines and the like. Aliphatic amines include ethylenediamine, 1,3-diaminopropane, 1,4-diaminopropane, hexamethylenediamine, 2,5-dimethylhexamethylenediamine, trimethylhexamethylenediamine, diethylenetriamine, iminobispropylamine, bis ( Hexamethylene) triamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-hydroxyethylethylenediamine, tetra (hydroxyethyl) ethylenediamine and the like are exemplified. Examples of polyether amines include triethylene glycol diamine, tetraethylene glycol diamine, diethylene glycol bis (propylamine), polyoxypropylene diamine, polyoxypropylene triamines, and the like. Cycloaliphatic amines include isophorone diamine, metacene diamine, N-aminoethylpiperazine, bis (4-amino-3-methyldicyclohexyl) methane, bis (aminomethyl) cyclohexane, 3,9-bis (3-amino). Propyl) -2,4,8,10-tetraoxaspiro (5,5) undecane, norbornenediamine and the like. Aromatic amines include tetrachloro-p-xylenediamine, m-xylenediamine, p-xylenediamine, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, 2,4-diaminoanisole, 2,4 -Toluenediamine, 2,4-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diamino-1,2-diphenylethane, 2,4-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, m-aminophenol, m-aminobenzylamine, benzyldimethylamine, 2-dimethylaminomethyl) phenol, triethanolamine, methylbenzylamine, α- (m-aminophenyl) ethylamine, α- (p-aminophenyl) ethylamine Diaminodiethyldi Examples thereof include methyldiphenylmethane and α, α′-bis (4-aminophenyl) -p-diisopropylbenzene.

  The amine curing agents mentioned above may be used alone or in any combination and blending ratio. Moreover, it is preferable to use an amine hardening | curing agent so that it may become the range of 0.8-1.5 by the equivalent ratio of the functional group in a hardening | curing agent with respect to the epoxy group in an epoxy resin. Within this range, unreacted epoxy groups and functional groups of the curing agent are unlikely to remain, which is preferable.

[Imidazoles]
It is preferable to use imidazoles as the curing agent from the viewpoint of sufficiently proceeding the curing reaction and improving the heat resistance. Examples of imidazoles include 2-phenylimidazole, 2-ethyl-4 (5) -methylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1 -Cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino- 6- [2′-Methylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-ethyl-4′-methylimidazolyl- (1 ′)]-ethyl-s -Triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-tri Azine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and an epoxy resin and the above imidazoles Examples include adducts. In addition, since imidazoles have catalytic ability, they can generally be classified as curing accelerators described later, but in the present invention, they are classified as curing agents.

  The imidazoles listed above may be used alone or in combination of two or more in any combination and ratio. Moreover, it is preferable to use imidazoles in 0.01 to 20 weight% with respect to the sum total of all the epoxy resin components and imidazoles as solid content in an epoxy resin composition.

[Acid anhydride curing agent]
It is preferable to use an acid anhydride curing agent as the curing agent from the viewpoint of heat resistance. Examples of the acid anhydride curing agent include acid anhydrides and modified acid anhydrides.

  Examples of acid anhydrides include phthalic acid anhydride, trimellitic acid anhydride, pyromellitic acid anhydride, benzophenone tetracarboxylic acid anhydride, dodecenyl succinic acid anhydride, polyadipic acid anhydride, polyazelinic acid anhydride, polysebacic acid Anhydride, poly (ethyloctadecanedioic acid) anhydride, poly (phenylhexadecanedioic acid) anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride , Methyl hymic acid anhydride, tetrahydrophthalic acid anhydride, trialkyltetrahydrophthalic acid anhydride, methylcyclohexene dicarboxylic acid anhydride, methylcyclohexene tetracarboxylic acid anhydride, ethylene glycol bis trimellitate dianhydride, het acid anhydride , Najit Acid anhydride, methyl nadic acid anhydride, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexane-1,2-dicarboxylic acid anhydride, 3,4-dicarboxy- Examples include 1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, and the like.

  Examples of modified acid anhydrides include those obtained by modifying the above acid anhydride with glycol. Examples of glycols that can be used for modification include alkylene glycols such as ethylene glycol, propylene glycol, and neopentyl glycol; polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. It is done. Furthermore, a copolymer polyether glycol of two or more kinds of these and / or polyether glycol can also be used. In addition, in the modified product of acid anhydride, it is preferable to modify with 0.4 mol or less of glycol with respect to 1 mol of acid anhydride. When the modification amount is not more than the above upper limit, the viscosity of the epoxy resin composition does not become too high, the workability tends to be good, and the rate of the curing reaction with the epoxy resin also tends to be good. .

  The acid anhydride curing agents mentioned above may be used alone or in combination of two or more in any combination, blending amount and blending ratio. When an acid anhydride curing agent is used, it is preferably used so that the equivalent ratio of the functional group in the curing agent to the epoxy group in the epoxy resin is in the range of 0.8 to 1.5. Within this range, unreacted epoxy groups and functional groups of the curing agent are unlikely to remain, which is preferable.

[Organic phosphines]
Use of organic phosphines as the curing agent is preferable from the viewpoint of providing a cured product having excellent curability and high electrical reliability. Examples of organic phosphines include tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, phenylphosphine and the like, and phosphonium salts include tetraphenylphosphonium / tetraphenylborate, tetraphenylphosphonium / ethyltriphenylborate, Examples include tetrabutylphosphonium / tetrabutylborate, and examples of the tetraphenylboron salt include 2-ethyl-4-methylimidazole / tetraphenylborate, N-methylmorpholine / tetraphenylborate, and the like.

  The organic phosphines listed above may be used alone or in a combination of two or more in any combination and ratio. Moreover, it is preferable to use organic phosphines in the range of 0.1-20 weight% with respect to the sum total of all the epoxy resin components and organic phosphines as solid content in an epoxy resin composition.

[Other curing agents]
As a curing agent that can be used in the epoxy resin composition of the present invention, other than phenolic curing agents, amide curing agents, amine curing agents, imidazoles, acid anhydride curing agents, and organic phosphines, Examples include mercaptan curing agents, tertiary amines, phosphonium salts, tetraphenyl boron salts, organic acid dihydrazides, boron halide amine complexes, isocyanate curing agents, block isocyanate curing agents, and the like. The other hardening | curing agents mentioned above may be used only by 1 type, and 2 or more types may be mixed and used for them in arbitrary combinations and ratios.

<Other epoxy resins>
The epoxy resin composition of the present invention can contain other epoxy resins in addition to the epoxy resin of the present invention. By using other epoxy resins, the insufficient physical properties can be compensated or various physical properties can be improved.

  The other epoxy resin preferably has two or more epoxy groups in the molecule. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, phenol novolac type epoxy resin, Various epoxy resins such as a cresol novolac type epoxy resin, a phenol aralkyl type epoxy resin, a biphenyl type epoxy resin, a triphenylmethane type epoxy resin, and a dicyclopentadiene type epoxy resin can be used. These can be used alone or as a mixture of two or more.

  In the epoxy resin composition of the present invention, when the epoxy resin of the present invention and another epoxy resin are used, the blending amount of the epoxy resin of the present invention in all the epoxy resin components is preferably 1% by weight or more, and more Preferably, it is 5% by weight or more, while it is preferably 99% by weight or less, more preferably 95% by weight or less. When the ratio of the other epoxy resin is not less than the above lower limit value, the effect of improving the physical properties by blending the other epoxy resin can be sufficiently obtained, and in particular, it is more excellent in heat resistance than the epoxy resin itself of the present invention. Material can be obtained. On the other hand, because the ratio of the other epoxy resin is less than or equal to the above upper limit value, the effect of the epoxy resin of the present invention is sufficiently exerted, and there is a tendency that flexibility, low water absorption and strength can be obtained. preferable.

<Solvent>
The epoxy resin composition containing the epoxy resin of the present invention may be diluted by blending a solvent in order to appropriately adjust the viscosity of the epoxy resin composition at the time of handling during coating film formation. In the epoxy resin composition of the present invention, the solvent is used in order to ensure the handleability and workability in the molding of the epoxy resin composition, and the amount used is not particularly limited.

  Examples of the solvent that can be contained in the epoxy resin composition containing the epoxy resin of the present invention include ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone and cyclohexanone, esters such as ethyl acetate, and ethers such as ethylene glycol monomethyl ether. Amides such as N, N-dimethylformamide and N, N-dimethylacetamide, alcohols such as methanol and ethanol, alkanes such as hexane and cyclohexane, and aromatics such as toluene and xylene. The solvent mentioned above may be used only by 1 type, and may mix and use 2 or more types by arbitrary combinations and a ratio.

<Other ingredients>
In the epoxy resin composition containing the epoxy resin of the present invention, components other than those listed above (sometimes referred to as “other components” in the present invention) for the purpose of further improving the functionality. May be included. Other ingredients include inorganic fillers, coupling agents such as silane coupling agents, UV inhibitors, antioxidants, plasticizers, fluxes, flame retardants, colorants, dispersants, emulsifiers, low elasticity agents, diluents. , Antifoaming agents, ion trapping agents and the like.

[Cured product]
A cured product obtained by curing the epoxy resin composition of the present invention is excellent in balance of flexibility, low water absorption, and strength, and exhibits excellent cured properties. The term “curing” as used herein means that the epoxy resin composition is intentionally cured by heat and / or light, and the degree of curing may be controlled by desired physical properties and applications. . The degree of progression may be completely cured or semi-cured, and is not particularly limited. However, the reaction rate of the curing reaction between the epoxy group and the curing agent is usually 5 to 95%.

  The curing method of the epoxy resin composition when the epoxy resin composition of the present invention is cured or semi-cured to obtain a cured product or semi-cured product varies depending on the blending component and blending amount in the epoxy resin composition, but usually And heating conditions of 60 to 180 minutes at 80 to 200 ° C. This heating may be performed in a two-stage process of primary heating at 80 to 160 ° C. for 10 to 30 minutes and secondary heating at 120 to 200 ° C. that is 40 to 120 ° C. higher than the primary heating temperature for 60 to 150 minutes, This is preferable from the viewpoint of reducing curing failure.

  When producing the resin semi-cured product, the curing reaction of the epoxy resin composition is advanced to such an extent that the shape can be maintained by heating or the like. When the epoxy resin composition contains a solvent, most of the solvent is removed by techniques such as heating, decompression, and air drying, but a solvent of 5% by mass or less may remain in the resin semi-cured product. .

[Use]
The epoxy resin of the present invention and the epoxy resin composition containing the epoxy resin have sufficient flexibility to be applied to processes such as casting and film forming / coating, and have an excellent balance between low water absorption and strength. It can be applied to various fields such as adhesives, paints, optical members, civil engineering materials, and insulating materials for electrical and electronic parts. In particular, it is useful as an insulating casting material, a laminate material, a sealing material, etc. in the electric / electronic field, and examples thereof include a laminate for an electric / electronic circuit and a sealing material for an electric / electronic circuit. Examples of the use of the epoxy resin of the present invention and the epoxy resin composition containing the epoxy resin include semiconductor sealing materials, underfill materials, 3D-LSI interchip fills, die bonding materials, film adhesives, liquid adhesives, etc. Adhesives, multilayer printed wiring boards, laminates for electrical and electronic circuits such as capacitors, insulating sheets, prepregs, heat dissipation boards, or adhesion improvers and flexibility imparting materials for electrical and electronic applications, etc. It is not limited to these at all.

In the present invention, the “laminate for electric / electronic circuit” is a laminate of a layer containing the epoxy resin composition of the present invention and a conductive metal layer made of copper, aluminum, an alloy thereof or the like. As long as the layer containing the epoxy resin composition of the present invention and the conductive metal layer are laminated, it can be used as a concept including, for example, a capacitor instead of an electric / electronic circuit. In addition, the layer which consists of 2 or more types of epoxy resin compositions may be formed in the laminated board for electric / electronic circuits, and the epoxy resin composition of this invention should just be used in at least 1 layer. . Two or more kinds of conductive metal layers may be formed.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not limited at all by the following example. In addition, the value of various manufacturing conditions and evaluation results in the following examples has a meaning as a preferable value of the upper limit or the lower limit in the embodiment of the present invention, and the preferable range is the above-described upper limit or lower limit value. A range defined by a combination of values of the following examples or values of the examples may be used. In the following, all “parts” indicate “parts by weight”. In addition, the following measurement methods for various physical properties and characteristics are as follows.

1) Weight average molecular weight and number average molecular weight Using "HLC-8320GPC EcoSEC (registered trademark)" manufactured by Tosoh Corporation, and under the following measurement conditions, as standard polystyrene, TSK Standard Polystyrene: F-128 (Mw1,090, 000, Mn 1,030,000), F-10 (Mw 106,000, Mn 103,000), F-4 (Mw 43,000, Mn 42,700), F-2 (Mw 17,200, Mn 16,900), A- A calibration curve using 5000 (Mw 6,400, Mn 6,100), A-2500 (Mw 2,800, Mn 2,700), A-300 (Mw 453, Mn 387) is prepared, and the weight average molecular weight and number average molecular weight are polystyrene. It was measured as a converted value.
Column: “TSKGEL SuperHM-H + H5000 + H4000 + H3000 + H2000” manufactured by Tosoh Corporation
Eluent: Tetrahydrofuran Flow rate: 0.5 ml / min
Detection: UV (wavelength 254 nm)
Temperature: 40 ° C
Sample concentration: 0.1% by weight
Injection volume: 10 μl

2) Value of n The value of n and the average value in the formula (1) were calculated from the number average molecular weight determined above.

3) Epoxy equivalent Measured according to JIS K7236 and expressed as a solid content converted value.

4) Glass transition temperature (Tg)
About the epoxy resin and epoxy resin hardened | cured material, SII nanotechnology Co., Ltd. product differential scanning calorimeter "DSC7020" was used, and it heated up at 30 degreeC to 200 degreeC at 10 degree-C / min, and measured the glass transition temperature. The glass transition temperature mentioned here was measured based on “midpoint glass transition temperature: Tmg” described in JIS K7121 “Method for measuring plastic transition temperature”.

5) Water absorption rate (preparation of test piece)
Low molecular weight epoxy resin: After defoaming the epoxy resin composition under reduced pressure, it is poured into a mold having a diameter of 50 mm and a height of 3 mm, heated at 150 ° C. for 1 hour, and then cured at 180 ° C. for 1 hour. A specimen was obtained.
High molecular weight epoxy resin: Using an applicator, the epoxy resin composition was coated on a separator (silicone-treated polyethylene terephthalate film), heated at 150 ° C. for 1 hour, and then cured at 180 ° C. for 1 hour. This cured epoxy resin film was cut out to 40 mm × 40 mm to obtain a test piece.
(Test conditions)
The cured product of the epoxy resin composition was dried at 105 ° C. for 2 hours, and the water absorption rate after being left under the following conditions was calculated by the following formula using Espec HAST chamber EHS-211MD.
Low molecular weight epoxy resin: left at 121 ° C. and 100% RH for 24 hours. The low water absorption was evaluated as acceptable if the water absorption was 3.5 or less, and rejected otherwise.
High molecular weight epoxy resin: left for 168 hours at 85 ° C. and 85% RH. The low water absorption was evaluated as acceptable if the water absorption was 0.9 or less, and rejected otherwise.
(Water absorption) = [{(Mass of test piece after being left) − (Mass of test piece before being left)} / (Mass of test piece before being left)] × 100

6) Bending test (flexural modulus / bending strength)
(Creation of specimen)
Two sheets of a 200 mm × 200 mm × 8 mm glass plate with a release polyethylene terephthalate film attached thereto were prepared, and one of them was placed so that the side to which the film was attached was up. Set a silicone tube with an inner diameter of 4 mm in this shape in a U-shape, and place a metal spacer with a thickness of 4 mm at the four corners of the glass plate, and then place the other glass plate with film facing the film side. Then, two glass plates were fixed with a small vise to prepare a mold for producing a cured product. The epoxy resin composition was degassed under reduced pressure, poured into a prepared mold, heated at 150 ° C. for 1 hour, and then cured at 180 ° C. for 1 hour. This epoxy resin cured product was cut out to 10 mm × 100 mm to obtain a test piece.
(Test conditions)
INSTRON 5582 type precision universal testing machine made by Instron is used and JIS
The test was conducted according to K7171. It was evaluated whether the cured specimen of the epoxy resin composition was broken, and the flexural modulus and flexural strength were measured.

7) Tensile test (tensile elongation / tensile strength)
(Creation of specimen)
Low molecular weight epoxy resin: mold release P on one side of a glass plate of 200 mm x 200 mm x 8 mm
Two pieces of ET film were prepared, and one of them was placed so that the side on which the film was attached was up. Set a silicon tube with an inner diameter of 3 mm in a U-shape on top of this, and place a metal spacer with a thickness of 3 mm at the four corners of the glass plate, and make the other glass plate with film face the film side. Then, two glass plates were fixed with a small vise to prepare a mold for producing a cured product. The epoxy resin composition was degassed under reduced pressure, poured into a prepared mold, heated at 150 ° C. for 1 hour, and then cured at 180 ° C. for 1 hour. This cured epoxy resin was punched out into a dumbbell shape to obtain a test piece.
High molecular weight epoxy resin: Using an applicator, the epoxy resin composition was coated on a separator (silicone-treated polyethylene terephthalate film), heated at 150 ° C. for 1 hour, and then cured at 180 ° C. for 1 hour. This cured epoxy resin film was punched into a dumbbell shape to obtain a test piece.
(Test conditions)
Tensile elongation and tensile strength were measured according to JIS K7161 using an Instron precision universal testing machine “INSTRON 5582 type”.

8) Strength Low molecular weight epoxy resin: In the bending test of 6), those having a flexural modulus of 2000 MPa or more and a bending strength of 70 MPa or more were accepted, and those not corresponding thereto were rejected.
In the tensile test of high molecular weight epoxy resin: 7), those having a tensile strength of 40 MPa or more were accepted, and those having a tensile strength of less than 40 MPa were rejected.

9) Flexibility Low molecular weight epoxy resin: In the bending test of 6), the test piece was not broken, and the broken one was rejected.
In a tensile test of high molecular weight epoxy resin: 7), a test piece having a tensile elongation of 6% or more and a tensile strength of 30 MPa or more was regarded as acceptable, and a material not corresponding to this was regarded as unacceptable.

[material]
The raw materials, catalysts, solvents and solvents used in the following examples and comparative examples are as follows.

<Bifunctional epoxy resin>
(A-1): 1,6-hexanediol diglycidyl ether (trade name “YED216D” manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 116 g / equivalent, m≈0.01)

<Divalent hydroxyl group-containing compound>
(B-1): 1,1-bis- (4-hydroxy-3-methylphenyl) cyclododecane (hydroxyl equivalent: 190 g / equivalent)
(B-2): 1,1-bis (4-hydroxyphenyl) cyclododecane (hydroxyl equivalent: 176 g / equivalent)
(B-3): 9,9-bis (2-methyl-4-hydroxyphenyl) fluorene (trade name “BisOC-FL” manufactured by Honshu Chemical Industry Co., Ltd., hydroxyl equivalent 189 g / equivalent)
(B-4): 4,4 ′-(3,3,5-trimethylcyclohexylidene) bisphenol (trade name “BisP-TMC” manufactured by Honshu Chemical Industry Co., Ltd., hydroxyl equivalent 155 g / equivalent)
(B-5): (4,4′-cyclohexylidenebisphenol (trade name “Bis-Z” manufactured by Honshu Chemical Industry Co., Ltd., hydroxyl group equivalent 134 g / equivalent)
(B-6): 4,4 ′-(1-α-methyl-benzylidene) bisphenol (trade name “BisP-AP” manufactured by Honshu Chemical Industry Co., Ltd., hydroxyl equivalent 145 g / equivalent)
(B-7): Bisphenol F (hydroxyl equivalent 100 g / equivalent)
(B-8): Bisphenol A (hydroxyl group equivalent 114 g / equivalent)

<Catalyst>
(C-1): Ethyltriphenylphosphonium iodide 30 wt% methyl cellosolve solution (C-2): Triphenylphosphine 20 wt% MEK solution (C-3): Tetramethylammonium hydroxide 27 wt% aqueous solution

<Solvent (for reaction) and solvent (for dilution)>
(S-1): Cyclohexanone (S-2): Methyl ethyl ketone

<Other epoxy resins>
(D-1): Bisphenol A novolak type polyfunctional epoxy resin (trade name “157S70” manufactured by Mitsubishi Chemical Corporation)
(D-2): Epoxy resin obtained by reacting bisphenol acetophenone and 3,3 ′, 5,5′-tetramethylbiphenol diglycidyl ether (epoxy equivalent 12,000 g / equivalent, weight average molecular weight 36,000 ) 30% by weight MEK / cyclohexanone mixed solution (weight ratio of MEK to cyclohexanone 1: 1)
(D-3): Bisphenol A novolac type polyfunctional epoxy resin 80 wt% MEK solution (trade name “157S65B80” manufactured by Mitsubishi Chemical Corporation)

<Curing agent>
(E-1): Bisphenol A novolak resin (trade name “YLH129” manufactured by Mitsubishi Chemical Corporation)
(E-2): 2-ethyl-4 (5) -methylimidazole (trade name “EMI-24” manufactured by Mitsubishi Chemical Corporation) 20% by weight MEK solution

[Production and evaluation of low molecular weight epoxy resins]
<Examples 1-1 to 1-6 and Comparative Examples 1-1 and 1-2>
A bifunctional epoxy resin, a divalent hydroxyl group-containing compound, a catalyst and a solvent (preliminarily used as a catalyst solution) were placed in a pressure-resistant reaction vessel equipped with a stirrer with the composition shown in Table 1,
After reacting at 0 ° C. for 5 hours, the obtained resin was analyzed. The results are shown in Table-1.

<Examples 2-1 to 2-6 and Comparative Examples 2-1 to 2-3>
The epoxy resin obtained in each of Examples 1-1 to 1-6 and Comparative Examples 1-1 and 1-2, the other epoxy resin, and the curing agent were blended with the formulation shown in Table 2, and stirred well. Thus, an epoxy resin composition was obtained. These epoxy resin compositions were cured by heating at 150 ° C. for 1 hour and then by heating at 180 ° C. for 1 hour to obtain a cured epoxy resin. About these epoxy resin hardened | cured materials, the glass transition temperature (Tg) measurement, the water absorption rate measurement, and the bending test were done by the above-mentioned method. The results are shown in Table-2.

[Evaluation results (low molecular weight epoxy resin)]
From the results of Table 2, the cured products of Examples 2-1 to 2-6 obtained using the epoxy resin of the present invention are more flexible than those of Comparative Examples 2-1 to 2-3. It can be seen that it has an excellent balance of properties, low water absorption and strength.

[Production and evaluation of high molecular weight epoxy resins and epoxy resin compositions]
<Examples 3-1, 3-2 and Comparative Example 3-1>
A bifunctional epoxy resin, a divalent hydroxyl group-containing compound, a catalyst and a solvent having the composition shown in Table 3 were placed in a pressure-resistant reaction vessel equipped with a stirrer and reacted at 160 ° C. for 5 hours in a nitrogen gas atmosphere. Was added to adjust the solid content concentration. After removing the solvent from the reaction product by a conventional method, the obtained epoxy resin was analyzed. The results are shown in Table-3.

<Examples 4-1, 4-2 and Comparative Examples 4-1, 4-2>
The epoxy resin obtained in each of Examples 3-1 and 3-2 and Comparative Example 3-1 with the formulation shown in Table 4 was blended, and the epoxy resin composition was mixed well and stirred. I got a thing. These epoxy resin compositions are applied to a separator (silicone-treated polyethylene terephthalate film) with an applicator, heated at 150 ° C. for 1 hour, and further heated at 180 ° C. for 1 hour to be cured, and cured epoxy resin. Film was obtained. About the film of these epoxy resin hardened | cured materials, the glass transition temperature (Tg) measurement, the water absorption rate measurement, and the tension test were done by the above-mentioned method. The results are shown in Table-4.

[Evaluation results (high molecular weight epoxy resin)]
From the results in Table 4, the cured products of Examples 4-1 and 4-2 obtained using the epoxy resin of the present invention are more flexible than those of Comparative Examples 4-1 and 4-2. It can be seen that it has an excellent balance between low water absorption and strength.

  The epoxy resin of the present invention and the epoxy resin composition containing the epoxy resin have sufficient flexibility to be applied to processes such as casting and film forming / coating, and have an excellent balance between low water absorption and strength. It can be applied to various fields such as adhesives, paints, optical members, civil engineering materials, and insulating materials for electrical and electronic parts. In particular, it is useful as an insulating casting material, laminated material, sealing material, etc. in the electric / electronic field. Examples of the use of the epoxy resin of the present invention and the epoxy resin composition containing the epoxy resin include semiconductor sealing materials, underfill materials, 3D-LSI interchip fills, die bonding materials, film adhesives, liquid adhesives, etc. Adhesives, multilayer printed wiring boards, laminates for electrical and electronic circuits such as capacitors, insulating sheets, prepregs, heat dissipation boards, or adhesion improvers and flexibility imparting materials for electrical and electronic applications, etc. It is not limited to these at all.

Claims (17)

An epoxy resin represented by the following formula (1).

(In the above formula (1), A includes at least the chemical structure represented by the above formula (2) and the chemical structure represented by the formula (3), and R is represented by a hydrogen atom or the above formula (4). N is a number from 1 to 250. In the above formula (3), X is a direct bond, a divalent hydrocarbon group having 1 to 20 carbon atoms, -O-, -S-, -SO. ₂ and -CO-, and R ^{1 to} R ⁸ may be different from each other, and are a group selected from a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, or a halogen element. The total number of carbon atoms contained in the chemical structure represented by 3) is 16 or more and 50 or less.)   2. The epoxy resin according to claim 1, wherein the chemical structure represented by the formula (2) is contained in the formula (1) in an amount of 1 to 99 mol% based on the total number of moles of A.   The molar ratio between the chemical structure represented by the formula (2) and the chemical structure represented by the formula (3) is 1/99 to 99/1 as A in the formula (1). The epoxy resin according to 1 or 2. An epoxy resin obtained by reacting a bifunctional epoxy resin represented by the following formula (5) with a divalent hydroxyl group-containing compound represented by the following formula (6).

(In the above formulas (5) and (6), A ′ has at least the chemical structure represented by the above formula (2 ′) and the chemical structure represented by the above formula (3 ′). , M is an average value of the number of repetitions and is 0 or more and 6. or less In the above formula (3 ′), X ′ is a direct bond, a divalent hydrocarbon group having 1 to 20 carbon atoms, —O—, —S. —, —SO ₂ — and —CO—, R ′ ^{1 to} R ′ ⁸ may be different from each other, and are selected from a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, or a halogen element. And the total number of carbon atoms contained in the chemical structure represented by the formula (3 ′) is 16 or more and 50 or less.)   5. The epoxy resin according to claim 4, wherein in the formulas (5) and (6), the chemical structure represented by the formula (2 ′) is contained in an amount of 1 to 99 mol% based on the total number of moles of A ′. .   As A ′ in the formula (5) and the formula (6), the molar ratio between the chemical structure represented by the formula (2 ′) and the chemical structure represented by the formula (3 ′) is 1/99. The epoxy resin of Claim 4 or 5 which is -99/1.   The epoxy resin according to any one of claims 1 to 6, wherein an epoxy equivalent is 200 g / equivalent or more and 30,000 g / equivalent or less.   The epoxy resin according to any one of claims 1 to 7, wherein the weight average molecular weight is 1,000 to 100,000.   The epoxy resin composition containing the epoxy resin of any one of Claims 1 thru | or 8, and a hardening | curing agent.   The epoxy resin composition of Claim 9 which contains 0.01-100 weight part of hardening | curing agents with respect to 100 weight part of said epoxy resins.   The curing agent is at least one selected from the group consisting of a phenolic curing agent, an amide curing agent, an amine curing agent, an imidazole, an acid anhydride curing agent, and an organic phosphine. The epoxy resin composition described in 1.   The sealing material for electric / electronic circuits which consists of an epoxy resin composition of any one of Claims 9 thru | or 11.   The laminated board for electric / electronic circuits which consists of an epoxy resin composition of any one of Claims 9 thru | or 11. The optical member which consists of an epoxy resin composition of any one of Claims 9 thru | or 11.   An adhesive comprising the epoxy resin composition according to any one of claims 9 to 11.   The coating material which consists of an epoxy resin composition of any one of Claims 9 thru | or 11.   Hardened | cured material formed by hardening | curing the epoxy resin composition of any one of Claims 9 thru | or 11.