JP7329350B2 - Curable epoxy resin composition - Google Patents

Description

The present invention relates to curable epoxy resin compositions.

In recent years, the output of optical semiconductor devices has been increasing, and the resin used in optical semiconductor devices forms a cured product that provides good optical properties (e.g., transparency, light reflectivity), water resistance, and heat resistance. A resin capable of

In an optical semiconductor device, a cured product of the above resin is sometimes used as a sealing material for covering the optical semiconductor element for the purpose of protecting the optical semiconductor element. In such a sealing material, the coloration of the sealing material progresses due to the heat emitted from the optical semiconductor element, and the light that should be originally output is absorbed, and as a result, it is output from the optical semiconductor device. There is a problem that the luminous intensity of the light decreases over time. Therefore, there is a demand for a sealing material with higher heat resistance.

A curable epoxy resin composition containing an alicyclic epoxy compound and norbornane-2,3-dicarboxylic anhydride as a curing agent has been proposed as a sealing agent for forming a sealing material with high heat resistance. has been proposed (Patent Document 1). However, the cured product of the curable epoxy resin composition has a problem of poor flexibility and poor impact resistance.

A resin composition containing an epoxy resin, an acid anhydride as a curing agent, and a thiol has also been proposed (Patent Document 2). However, with such a resin composition, sufficient flexibility could not be obtained. In the present technology, the epoxy resin is obtained by heat curing after the composition is prepared, and the acid anhydride and thiol, which are curing agents, are not reacted in advance.

In addition, curable epoxy resin compositions are used in various applications other than sealants, but none are known to have flexibility and durability under high temperature and high humidity. Therefore, if these performances are improved, application in many uses is expected.

JP 2016-160352 A Japanese Patent No. 5224734

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a curable epoxy resin composition capable of forming a cured product having high heat resistance, water resistance and flexibility.

As a result of intensive studies to solve the above problems, the present inventors have found that a curable epoxy resin composition containing an alicyclic epoxy compound, a specific curing agent, and a curing accelerator provides high heat resistance, water resistance, and The inventors have found that it is possible to form a cured product having flexibility, and completed the present invention.

［式中、Ｒｘは、同一又は異なって、水素原子、下記式（ｂ１）

（Ｒ₁～Ｒ₆は、同一又は異なって、水素原子又は直鎖若しくは分岐状の炭素数１～４のアルキル基を示す。波線は結合部位を表す。）
で表される構造を有する基、又は下記式（ｂ２）

（Ｒ₇～Ｒ₁₀は、同一又は異なって、水素原子又は直鎖若しくは分岐状の炭素数１～４のアルキル基を示す。波線は結合部位を表す。）
で表される構造を有する基を示し、その１つ以上が式（ｂ１）又は（ｂ２）で表される構造を有する基である。Ａは、置換基を有していてもよく、主鎖中及び／又は側鎖中にヘテロ原子を含む官能基を有していてもよい、炭素数２～５０の、ａ価の直鎖又は分岐状炭化水素基である。ａは２～６の整数を示す。］
で表される酸無水物及び下記式（Ｂ２）

［式中、Ｒｘは、同一又は異なって、水素原子、下記式（ｂ１）

（Ｒ₁～Ｒ₆は、同一又は異なって、水素原子又は直鎖若しくは分岐状の炭素数１～４のアルキル基を示す。波線は結合部位を表す。）
で表される構造を有する基、又は下記式（ｂ２）

（Ｒ₇～Ｒ₁₀は、同一又は異なって、水素原子又は直鎖若しくは分岐状の炭素数１～４のアルキル基を示す。波線は結合部位を表す。）
で表される構造を有する基を示し、その１つ以上が式（ｂ１）又は（ｂ２）で表される構造を有する基である。Ｒｓは、同一又は異なって、水素原子又はメチル基である。Ｒは、ヘテロ原子を含む官能基を有してもよい、炭素数２～２８の、直鎖、分岐状、又は環状の構造を有する（ｂ＋ｃ）価の基である。Ｒ’は、同一又は異なって、水素原子、炭素数が１～８のアルキル基、チオール基、又は下記式（ｂ３）

（式中、Ｒ₁₁及びＲ₁₂は、異なって、Ｒ₁₁はチオール基又はメチル基を示し、Ｒ₁₂は水素原子又はチオール基を示す。波線は結合部位を表す。）
で表される基を示す。ｂとｃは、ｂ＋ｃ＝２～６であって、ｂは０を含む整数であり、ｃは１～６の整数を示す。］
で表される酸無水物からなる群より選択される少なくとも１つであることを特徴とする硬化性エポキシ樹脂組成物を提供する。 That is, in the present invention, a curable epoxy resin composition containing an alicyclic epoxy compound (A), a curing agent (B), and a curing accelerator (C),
Curing agent (B) is represented by the following formula (B1)

[Wherein, Rx is the same or different, a hydrogen atom, the following formula (b1)

(R ₁ to R ₆ are the same or different and represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. A wavy line represents a bonding site.)
A group having a structure represented by the following formula (b2)

(R ₇ to R ₁₀ are the same or different and represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. Wavy lines represent bonding sites.)
is a group having a structure represented by formula (b1) or (b2). A may have a substituent, may have a functional group containing a heteroatom in the main chain and / or side chain, having 2 to 50 carbon atoms, a-valent straight chain or It is a branched hydrocarbon group. a represents an integer of 2 to 6; ]
and an acid anhydride represented by the following formula (B2)

[Wherein, Rx is the same or different, a hydrogen atom, the following formula (b1)

(R ₁ to R ₆ are the same or different and represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. A wavy line represents a bonding site.)
A group having a structure represented by the following formula (b2)

(R ₇ to R ₁₀ are the same or different and represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. Wavy lines represent bonding sites.)
is a group having a structure represented by formula (b1) or (b2). Rs are the same or different and are a hydrogen atom or a methyl group. R is a (b+c)-valent group having a linear, branched or cyclic structure and having 2 to 28 carbon atoms, which may have a functional group containing a heteroatom. R' is the same or different and is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a thiol group, or the following formula (b3)

(In the formula, R ₁₁ and R ₁₂ are different, R ₁₁ represents a thiol group or a methyl group, R ₁₂ represents a hydrogen atom or a thiol group, and the wavy line represents a binding site.)
represents a group represented by b and c are such that b+c=2-6, b is an integer including 0, and c is an integer of 1-6. ]
To provide a curable epoxy resin composition characterized by being at least one selected from the group consisting of acid anhydrides represented by

（式中、ｎは１～１０の整数を示す。波線は結合部位を示す。）
で表される基のいずれか１つであることが好ましい。 R in the acid anhydride represented by the formula (B2) is represented by the following formulas (b4) to (b8)

(In the formula, n represents an integer of 1 to 10. A wavy line represents a binding site.)
Any one of the groups represented by is preferable.

The alicyclic epoxy group of the alicyclic epoxy compound (A) is preferably a cyclohexene oxide group.

で表される化合物であることが好ましい。 The alicyclic epoxy compound (A) has the following formula (I-1)

It is preferably a compound represented by.

Moreover, in this invention, the hardened|cured material of the said curable epoxy resin composition is provided.

The present invention also provides a sealant containing the curable epoxy resin composition.

The present invention also provides an adhesive containing the curable epoxy resin composition.

In addition, the present invention provides a coating agent containing the curable epoxy resin composition.

Moreover, in this invention, the optical member containing the said hardened|cured material is provided.

Since the curable epoxy resin composition of the present invention has the above constitution, a cured product having high heat resistance, water resistance and flexibility can be obtained by curing. Therefore, the resin composition can be used as a sealing agent, an adhesive and a coating agent. Moreover, the cured product can be used as an optical member.

1 is a ¹ H-NMR chart of the product obtained in Reference Example 1. FIG. An optical semiconductor device in which an optical semiconductor element is encapsulated with a cured product of a resin composition produced in the evaluation of Examples. The left figure (a) is a perspective view, and the right figure (b) is a sectional view.

<Curable epoxy resin composition>
The curable epoxy resin composition of the present invention comprises an alicyclic epoxy compound (A), a curing agent (B), and a curing accelerator (C), wherein the curing agent (B) is represented by the formula (B1). and at least one selected from the group consisting of the acid anhydride represented by the formula (B2).

[Alicyclic epoxy compound (A)]
The alicyclic epoxy compound (alicyclic epoxy resin) (A), which is an essential component of the curable epoxy resin composition of the present invention, has an alicyclic (aliphatic hydrocarbon ring) structure in the molecule (in one molecule). It is a compound having at least an epoxy group (oxiranyl group), and known or commonly used alicyclic epoxy compounds can be used. As the alicyclic epoxy compound (A), more specifically, for example, a compound having an epoxy group (alicyclic epoxy group) composed of two adjacent carbon atoms and an oxygen atom constituting an alicyclic ring ( (sometimes referred to as "compound (A-1)"), and compounds having an epoxy group directly bonded to an alicyclic ring with a single bond (sometimes referred to as "compound (A-2)").

As the compound (A-1), known or commonly used compounds having one or more alicyclic epoxy groups in the molecule can be used without particular limitation. As the alicyclic epoxy group, a cyclohexene oxide group is preferable from the viewpoint of the heat resistance of the cured product. In particular, from the viewpoint of heat resistance of the cured product, the compound (A-1) is preferably a compound having two or more cyclohexene oxide groups in the molecule, more preferably a compound represented by the following formula (I). be.

In formula (I), X represents a single bond or a linking group (a divalent group having one or more atoms). Examples of the linking group include a divalent hydrocarbon group, an alkenylene group in which part or all of the carbon-carbon double bond is epoxidized (sometimes referred to as an "epoxidized alkenylene group"), a carbonyl group, Examples include ether bond, ester bond, carbonate group, amide group, and groups in which a plurality of these are linked. One or more carbon atoms constituting the cyclohexane ring (cyclohexene oxide group) in formula (I) may be bonded with a substituent such as an alkyl group.

Compounds in which X in formula (I) is a single bond include (3,4,3′,4′-diepoxy)bicyclohexyl and the like.

Examples of the divalent hydrocarbon group include linear or branched alkylene groups having 1 to 18 carbon atoms, divalent alicyclic hydrocarbon groups, and the like. Examples of linear or branched alkylene groups having 1 to 18 carbon atoms include methylene group, methylmethylene group, dimethylmethylene group, ethylene group, propylene group and trimethylene group. Examples of the divalent alicyclic hydrocarbon group include 1,2-cyclopentylene group, 1,3-cyclopentylene group, cyclopentylidene group, 1,2-cyclohexylene group, 1,3- Cycloalkylene groups (including cycloalkylidene groups) such as a cyclohexylene group, a 1,4-cyclohexylene group, and a cyclohexylidene group are included.

Examples of the alkenylene group in the alkenylene group in which part or all of the carbon-carbon double bond is epoxidized (epoxidized alkenylene group) include vinylene group, propenylene group, 1-butenylene group, 2-butenylene group, butadienylene linear or branched alkenylene groups having 2 to 8 carbon atoms, such as groups, pentenylene groups, hexenylene groups, heptenylene groups, and octenylene groups. In particular, the epoxidized alkenylene group is preferably an alkenylene group in which all of the carbon-carbon double bonds are epoxidized, more preferably an alkenylene group having 2 to 4 carbon atoms in which all of the carbon-carbon double bonds are epoxidized. It is an alkenylene group.

As the linking group for X, a linking group containing an oxygen atom is particularly preferable, and specifically, -CO-, -O-CO-O-, -COO-, -O-, -CONH-, epoxy groups in which a plurality of these groups are linked; groups in which one or more of these groups are linked to one or more of divalent hydrocarbon groups, and the like. Examples of the divalent hydrocarbon group include those exemplified above.

Representative examples of the compound represented by formula (I) include compounds represented by the following formulas (I-1) to (I-10), 2,2-bis(3,4-epoxycyclohexane-1 -yl)propane, 1,2-bis(3,4-epoxycyclohexan-1-yl)ethane, 1,2-epoxy-1,2-bis(3,4-epoxycyclohexan-1-yl)ethane, bis (3,4-epoxycyclohexylmethyl)ether and the like. l' and m' in the following formulas (I-5) and (I-7) each represent an integer of 1 to 30. R in the following formula (I-5) is an alkylene group having 1 to 8 carbon atoms, and is a methylene group, ethylene group, propylene group, isopropylene group, butylene group, isobutylene group, s-butylene group, pentylene group, hexylene. linear or branched alkylene groups such as radicals, heptylene groups, and octylene groups. Among these, straight-chain or branched-chain alkylene groups having 1 to 3 carbon atoms such as methylene, ethylene, propylene and isopropylene are preferred. n1 to n6 in the following formulas (I-9) and (I-10) each represent an integer of 1 to 30.

Examples of the compound (A-2) include compounds (epoxy resins) represented by the following formula (II).

In formula (II), R ¹ represents a p-valent organic group. p represents an integer of 1-20. The p-valent organic group includes, for example, a p-valent organic group having a structure formed by removing p hydroxy groups from the structural formula of an organic compound having p hydroxy groups described below.

In formula (II), q represents an integer of 1-50. When p is an integer of 2 or more, multiple qs may be the same or different. The sum of q in formula (II) is an integer of 3-100.

In formula (II), R ² is a substituent on the cyclohexane ring shown in the formula and represents any of the groups represented by formulas (IIa) to (IIc) below. The bonding position of R ² on the cyclohexane ring is not particularly limited, but usually, when the positions of the two carbon atoms of the cyclohexane ring bonded to the oxygen atom are the 1st and 2nd positions, the carbon atom at the 4th or 5th position is. Also, when the compound represented by formula (II) has a plurality of cyclohexane rings, the bonding positions of R ² in each cyclohexane ring may be the same or different. At least one of R ² in formula (II) is a group (epoxy group) represented by formula (IIa). In addition, when the compound represented by formula (II) has two or more R ² , the plurality of R ² may be the same or different.

In formula (IIc), R ³ represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkylcarbonyl group, or a substituted or unsubstituted arylcarbonyl group. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, butyl group, isobutyl group, s-butyl group, t-butyl group, pentyl group, hexyl group, octyl group, and 2-ethylhexyl. straight-chain or branched-chain alkyl groups having 1 to 20 carbon atoms such as groups. Examples of the alkylcarbonyl group include methylcarbonyl group (acetyl group), ethylcarbonyl group, n-propylcarbonyl group, isopropylcarbonyl group, n-butylcarbonyl group, isobutylcarbonyl group, s-butylcarbonyl group, t-butyl A linear or branched alkyl-carbonyl group having 1 to 20 carbon atoms such as a carbonyl group can be mentioned. Examples of the arylcarbonyl group include aryl-carbonyl groups having 6 to 20 carbon atoms such as a phenylcarbonyl group (benzoyl group), 1-naphthylcarbonyl group and 2-naphthylcarbonyl group.

Examples of substituents that the above alkyl group, alkylcarbonyl group, and arylcarbonyl group may have include substituents having 0 to 20 carbon atoms (more preferably 0 to 10 carbon atoms). Examples of the substituents include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom; hydroxy group; alkoxy group such as methoxy group, ethoxy group, propoxy group, isopropyloxy group, butoxy group and isobutyloxy group. (preferably C _1-6 alkoxy group, more preferably C _1-4 alkoxy group); alkenyloxy group such as allyloxy group (preferably C _2-6 alkenyloxy group, more preferably C _2-4 alkenyloxy group) Acyloxy groups (preferably C _1-12 acyloxy groups) such as acetyloxy group, propionyloxy group and (meth)acryloyloxy group; Mercapto group; Alkylthio groups such as methylthio group and ethylthio group (preferably C _1-6 alkylthio group, more preferably C _1-4 alkylthio group); alkenylthio group such as allylthio group (preferably C _2-6 alkenylthio group, more preferably C _2-4 alkenylthio group); carboxy group; methoxycarbonyl group, Alkoxycarbonyl groups (preferably C _1-6 alkoxy-carbonyl groups) such as ethoxycarbonyl group, propoxycarbonyl group and butoxycarbonyl group; amino group; dialkylamino group (preferably mono- or di-C _1-6 alkylamino group); acylamino group (preferably C _1-11 acylamino group) such as acetylamino group and propionylamino group; oxetanyl group-containing group such as ethyloxetanyloxy group groups; acyl groups such as an acetyl group and a _propionyl group; oxo groups; Further, examples of the substituent that the above-mentioned arylcarbonyl group may have include the above-mentioned substituted or unsubstituted alkyl group and the above-mentioned substituted or unsubstituted alkylcarbonyl group.

The ratio of the group (epoxy group) represented by the formula (IIa) to the total amount (100 mol%) of R ² in the compound represented by the formula (II) is not particularly limited, but is 40 mol% or more (for example, 40 to 100 mol %), more preferably 60 mol % or more, and still more preferably 80 mol % or more. When the ratio is 40 mol % or more, the heat resistance of the cured product tends to be further improved. The above ratio can be calculated by, for example, ¹ H-NMR spectrum measurement, oxirane oxygen concentration measurement, or the like.

^The compound represented by formula ( _II ) is not particularly limited. (active hydrogen) as a starting point), 1,2-epoxy-4-vinylcyclohexane (3-vinyl-7-oxabicyclo[4.1.0]heptane) is subjected to ring-opening polymerization (cationic polymerization), and then It is produced by epoxidation with an oxidizing agent.

Examples of the organic compound [R ¹ (OH) _p ] having p hydroxy groups in the molecule include aliphatic alcohols such as methanol, ethanol, propanol, butanol, pentanol, hexanol and octanol; ethylene glycol and diethylene glycol. , triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, pentanediol, 1,6-hexanediol, neopentyl glycol, neopentyl glycol ester, cyclohexanediol Polyhydric alcohols such as methanol, glycerin, diglycerin, polyglycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, hydrogenated bisphenol A, hydrogenated bisphenol F, hydrogenated bisphenol S; polyvinyl alcohol, polyvinyl acetate partial hydrolysis starch, acrylic polyol resin, styrene-allyl alcohol copolymer resin, polyester polyol, polycaprolactone polyol, polypropylene polyol, polytetramethylene glycol, polycarbonate polyols, hydroxyl group-containing polybutadiene, cellulose, cellulose acetate, cellulose acetate butyrate , oligomers or polymers having a hydroxy group, such as cellulose-based polymers such as hydroxyethyl cellulose.

The above 1,2-epoxy-4-vinylcyclohexane can be produced by a known or commonly used method, and is not particularly limited. obtained by partial epoxidation using A commercial product can also be used as 1,2-epoxy-4-vinylcyclohexane.

As the oxidizing agent, known or commonly used oxidizing agents such as hydrogen peroxide and organic peracids can be used without particular limitation. Examples of organic peracids include performic acid, peracetic acid, peroxide benzoic acid, trifluoroperacetic acid, and the like. Among them, peracetic acid is preferable because it is industrially available at low cost and has high stability.

More specifically, the ring-opening polymerization and epoxidation can be carried out, for example, according to the well-known and commonly used method described in JP-A-60-161973.

The weight average molecular weight of the compound represented by formula (II) in terms of standard polystyrene is not particularly limited, but is preferably from 300 to 100,000, more preferably from 1,000 to 10,000. When the weight average molecular weight is 300 or more, the heat resistance of the cured product tends to be improved. On the other hand, when the weight-average molecular weight is 100,000 or less, the viscosity tends to be too high and the fluidity during molding tends to be kept low. In addition, a weight average molecular weight is measured by a gel permeation chromatography (GPC) method.

The epoxy group equivalent weight (epoxy equivalent weight) of the compound represented by formula (II) is not particularly limited, but is preferably 50 to 1,000, more preferably 100 to 500. When the epoxy equivalent is 50 or more, the cured product tends to be less brittle. On the other hand, when the epoxy equivalent is 1000 or less, the mechanical strength of the cured product tends to improve. In addition, an epoxy equivalent is measured according to JISK7236:2001.

As the alicyclic epoxy compound (A), compound (A-1) and compound (A-2) are preferable from the viewpoint of heat resistance of the cured product. As the compound (A-1), from the viewpoint of heat resistance of the cured product, the compound represented by the formula (I-1) [3,4-epoxycyclohexylmethyl (3,4-epoxy)cyclohexanecarboxylate; For example, the trade name "Celoxide 2021P" (manufactured by Daicel Corporation)] is particularly preferable.

In the curable epoxy resin composition of the present invention, the alicyclic epoxy compound (A) may be used singly or in combination of two or more. The alicyclic epoxy compound (A) can also be produced by a known or commonly used method. You can also use the product.

The content (amount) of the alicyclic epoxy compound (A) in the curable epoxy resin composition of the present invention is not particularly limited, but is 1 to 90% with respect to the curable epoxy resin composition (100% by weight). % by weight is preferable, more preferably 10 to 80% by weight, still more preferably 20 to 70% by weight, particularly preferably 20 to 60% by weight. By using the alicyclic epoxy compound (A) within the above range, the heat resistance, water resistance and flexibility of the cured product tend to be improved. In this specification, the content of each component contained in the curable epoxy resin composition of the present invention (e.g., alicyclic epoxy compound (A), curing agent (B), curing accelerator (C), etc.) can be appropriately selected from within the ranges described so that the total is 100% by weight or less.

［式中、Ｒｘは、同一又は異なって、水素原子、下記式（ｂ１）

（Ｒ₁～Ｒ₆は、同一又は異なって、水素原子又は直鎖若しくは分岐状の炭素数１～４のアルキル基を示す。波線は結合部位を表す。）
で表される構造を有する基、又は下記式（ｂ２）

（Ｒ₇～Ｒ₁₀は、同一又は異なって、水素原子又は直鎖若しくは分岐状の炭素数１～４のアルキル基を示す。波線は結合部位を表す。）
で表される構造を有する基を示し、その１つ以上が式（ｂ１）又は（ｂ２）で表される構造を有する基である。Ａは、置換基を有していてもよく、主鎖中及び／又は側鎖中にヘテロ原子を含む官能基を有していてもよい、炭素数２～５０の、ａ価の直鎖又は分岐状炭化水素基である。ａは２～６の整数を示す。］
で表される酸無水物及び下記式（Ｂ２）

［式中、Ｒｘは、同一又は異なって、水素原子、下記式（ｂ１）

（Ｒ₁～Ｒ₆は、同一又は異なって、水素原子又は直鎖若しくは分岐状の炭素数１～４のアルキル基を示す。波線は結合部位を表す。）
で表される構造を有する基、又は下記式（ｂ２）

（Ｒ₇～Ｒ₁₀は、同一又は異なって、水素原子又は直鎖若しくは分岐状の炭素数１～４のアルキル基を示す。波線は結合部位を表す。）
で表される構造を有する基を示し、その１つ以上が式（ｂ１）又は（ｂ２）で表される構造を有する基である。Ｒｓは、同一又は異なって、水素原子又はメチル基である。Ｒは、ヘテロ原子を含む官能基を有してもよい、炭素数２～２８の、直鎖、分岐状、又は環状の構造を有する（ｂ＋ｃ）価の基である。Ｒ’は、同一又は異なって、水素原子、炭素数が１～８のアルキル基、チオール基、又は下記式（ｂ３）

（式中、Ｒ₁₁及びＲ₁₂は、異なって、Ｒ₁₁はチオール基又はメチル基を示し、Ｒ₁₂は水素原子又はチオール基を示す。波線は結合部位を表す。）
で表される基を示す。ｂとｃは、ｂ＋ｃ＝２～６であって、ｂは０を含む整数であり、ｃは１～６の整数を示す。］
で表される酸無水物からなる群より選択される少なくとも１つである。すなわち、硬化剤（Ｂ）は分子中に１又は２以上（２～６）の－Ｓ－Ｒｘ基を有する酸無水物である。 [Curing agent (B)]
The curing agent (B) in the curable epoxy resin composition of the present invention has the following formula (B1)

[Wherein, Rx is the same or different, a hydrogen atom, the following formula (b1)

(R ₁ to R ₆ are the same or different and represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. A wavy line represents a bonding site.)
A group having a structure represented by the following formula (b2)

(R ₇ to R ₁₀ are the same or different and represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. Wavy lines represent bonding sites.)
is a group having a structure represented by formula (b1) or (b2). A may have a substituent, may have a functional group containing a heteroatom in the main chain and / or side chain, having 2 to 50 carbon atoms, a-valent straight chain or It is a branched hydrocarbon group. a represents an integer of 2 to 6; ]
and an acid anhydride represented by the following formula (B2)

[Wherein, Rx is the same or different, a hydrogen atom, the following formula (b1)

(R ₁ to R ₆ are the same or different and represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. A wavy line represents a bonding site.)
A group having a structure represented by the following formula (b2)

(R ₇ to R ₁₀ are the same or different and represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. Wavy lines represent bonding sites.)
is a group having a structure represented by formula (b1) or (b2). Rs are the same or different and are a hydrogen atom or a methyl group. R is a (b+c)-valent group having a linear, branched or cyclic structure and having 2 to 28 carbon atoms, which may have a functional group containing a heteroatom. R' is the same or different and is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a thiol group, or the following formula (b3)

(In the formula, R ₁₁ and R ₁₂ are different, R ₁₁ represents a thiol group or a methyl group, R ₁₂ represents a hydrogen atom or a thiol group, and the wavy line represents a binding site.)
represents a group represented by b and c are such that b+c=2-6, b is an integer including 0, and c is an integer of 1-6. ]
is at least one selected from the group consisting of acid anhydrides represented by That is, the curing agent (B) is an acid anhydride having one or more (2 to 6) -S-Rx groups in the molecule.

As described above, it is known to use an acid anhydride and a thiol compound in combination as curing agents for epoxy resins. However, in the reaction between an acid anhydride having an unsaturated group and a thiol compound, in order to obtain the acid anhydride represented by the formula (B1) or the acid anhydride represented by the formula (B2), the enethiol reaction An operation (for example, addition reaction by ultraviolet irradiation or radical reaction) is required to generate a sulfide bond, and it is impossible to obtain the sulfide bond simply by mixing.

Furthermore, when using the acid anhydride represented by the formula (B1) or the acid anhydride represented by the formula (B2), compared to the case of using an acid anhydride and a thiol compound in combination, Good performance as a curing agent. The present inventors have found that an alicyclic epoxy compound (A) is cured by blending an acid anhydride represented by the formula (B1) or an acid anhydride represented by the formula (B2) as a curing agent. The present inventors have completed the present invention by discovering that a flexible epoxy resin composition can form a cured product having excellent flexibility and excellent durability under high temperature and high humidity conditions. Such an excellent effect can be obtained because the structure derived from the acid anhydride represented by the formula (B1) and the acid anhydride represented by the formula (B2) can increase the crosslink density, and as a result It is presumed that this is because flexibility is imparted by introducing a sulfide bond into the skeleton in addition to maintaining heat resistance.

Hereinafter, formula (b9), formula (b10), formula (b11), and formula (b12), which are structural units of the acid anhydride represented by formula (B1) and the acid anhydride represented by formula (B2) The compound represented by is explained.

式中、Ｒ₁～Ｒ₆は、同一又は異なって、水素原子又は直鎖若しくは分岐状の炭素数１～４のアルキル基を示す。

In the formula, R ₁ to R ₆ are the same or different and represent a hydrogen atom or a linear or branched C 1-4 alkyl group.

The compound represented by formula (b9) is 5-norbornene-2,3-dicarboxylic anhydride or a derivative thereof. The compound represented by the formula (b9) is a compound in which 0 to 4 (especially 0 to 2) of R ₁ to R ₆ are methyl groups from the viewpoint of moisture resistance and moisture absorption reflow resistance of the cured product. Methylnorbornene-2,3-dicarboxylic anhydride and norbornene-2,3-dicarboxylic anhydride are preferred, and more preferred.

The norbornene skeleton of the compound represented by formula (b9) has stereoisomers of an exo form and an endo form. In the compound represented by the formula (b9), when the abundance ratio of the exo form increases, the compound tends to become liquid at room temperature, which tends to facilitate handling. Therefore, it is preferable that the compound represented by the formula (b9) has a high proportion of the exo form. More specifically, the abundance ratio of the exo form in the compound represented by formula (b9) [exo form/(exo form + endo form)] is preferably 40% by weight or more, more preferably 50% by weight or more. . When the abundance ratio of the exo form is less than 40% by weight, the compound represented by the formula (3) tends to become solid at room temperature, and tends to be difficult to handle. The method for increasing the abundance ratio of the exo form to 40% by weight or more is not particularly limited, but as described in the specific examples below, the compound represented by the formula (b9) is isomerized to the exo form. methods and the like.

The term "methylnorbornene 2,3-dicarboxylic anhydride" used herein is a general term for isomers having different bonding positions of the methyl groups on the norbornene ring. Typical examples of methylnorbornene-2,3-dicarboxylic anhydride include 5-methylnorbornene-2,3-dicarboxylic anhydride.

Norbornene 2,3-dicarboxylic anhydride can be obtained, for example, by the Diels-Alder reaction of cyclopentadiene and maleic anhydride. Norbornene-2,3-dicarboxylic anhydride, which is usually obtained by the Diels-Alder reaction of cyclopentadiene and maleic anhydride, has an abundance ratio of endo form of 95% by weight or more. Norbornene 2,3-dicarboxylic anhydride with a high exo form abundance ratio (for example, norbornene 2,3-dicarboxylic anhydride with an exo form abundance ratio of 30% by weight or more objects) can be generated. Commercially available products of the compound represented by formula (b9) include 5-norbornene-2,3-dicarboxylic anhydride, trade name "MHAC-P" (manufactured by Hitachi Chemical Co., Ltd.).

式中、Ｒ₇～Ｒ₁₀は、同一又は異なって、水素原子又は直鎖若しくは分岐状の炭素数１～４のアルキル基を示す。

In the formula, R ₇ to R ₁₀ are the same or different and represent a hydrogen atom or a linear or branched C 1-4 alkyl group.

The compound represented by formula (b10) is 1,2,3,6-tetrahydrophthalic anhydride or a derivative thereof. Derivatives can include various alkyl substitutions. Examples include methyltetrahydrophthalic anhydride (4-methyltetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, etc.). Commercially available products of such compounds include trade names "HN-2200" and "HN-2000" (manufactured by Hitachi Chemical Co., Ltd.).

From the viewpoint of reactivity with the compound represented by the formula (b11) described later and performance when used as an epoxy resin curing agent, the compound represented by the formula (b9) is the compound represented by the formula (b10) is more preferable than the compound represented by

式中、Ａは、置換基を有していてもよく、主鎖中及び／又は側鎖中にヘテロ原子を含む官能基を有していてもよい、炭素数２～５０の、ｄ価の直鎖又は分岐状炭化水素基である。ｄは、２～６の整数を表す。

In the formula, A may have a substituent and may have a functional group containing a heteroatom in the main chain and/or side chain, having 2 to 50 carbon atoms, d-valent It is a straight chain or branched hydrocarbon group. d represents an integer of 2 to 6;

The compound represented by formula (b11) is an organic compound having multiple thiol groups. In A, having a functional group containing a heteroatom in the main chain and/or side chain means, for example, having a heteroatom between two or more carbon atoms constituting a hydrocarbon group. means

In the compound represented by formula (b11), A can be any hydrocarbon group that does not directly affect the enethiol reaction.

The hydrocarbon represented by A is not particularly limited, and is an a-valent linear or branched hydrocarbon group having 2 to 50 carbon atoms and containing a heteroatom in the main chain and/or side chain. It may have a functional group. The number of carbon atoms is more preferably 5 or more, most preferably 14 or more. Also, the number of carbon atoms is more preferably 36 or less, most preferably 28 or less. Substituents that may be present in A include, for example, an ether group, an ester group, a group having a cyclic hydrocarbon structure, a uryl group, a group having a heterocyclic structure, a sulfide group, an amino group, an amide group, and a urethane group. groups, ketone groups, and the like. Among these, those having two or more structures may be used. These functional groups may exist as side chain functional groups or may be functional groups forming part of the main chain.

The group having a cyclic hydrocarbon structure exemplified as a substituent that may be present in A includes a group having an aromatic ring such as a benzene ring and a naphthalene ring, and an alicyclic ring such as a cyclohexane ring. may be a group having The group having a heterocyclic structure includes arbitrary groups such as a group having a 1,3,5-triazine ring and a group having a 1,3,4,6-glycoluril ring. These substituents may be present in the main chain or in side chains.

式中、Ｒｓは、同一又は異なって、水素原子又はメチル基である。Ｒは、ヘテロ原子を含む官能基を有してもよい、炭素数２～２８の、直鎖、分岐状、又は環状の構造を有する（ｅ＋ｆ）価の基である。Ｒ’’は、同一又は異なって、水素原子、炭素数が１～８のアルキル基、チオール基、又は下記式（ｂ３）で表される基を示す。ｅとｆは、ｅ＋ｆ＝２～６であって、ｅは０を含む整数であり、ｆは１～６の整数を示す。

In the formula, Rs are the same or different and are a hydrogen atom or a methyl group. R is a (e+f) valent group having a linear, branched or cyclic structure with 2 to 28 carbon atoms which may have a functional group containing a heteroatom. R'' is the same or different and represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a thiol group, or a group represented by the following formula (b3). e and f are such that e+f=2-6, e is an integer including 0, and f is an integer of 1-6.

式中、Ｒ₁₁及びＲ₁₂は、異なって、Ｒ₁₁はチオール基又はメチル基を示し、Ｒ₁₂は水素原子又はチオール基を示す。波線は結合部位を表す。

In the formula, R ₁₁ and R ₁₂ are different, R ₁₁ represents a thiol group or a methyl group, and R ₁₂ represents a hydrogen atom or a thiol group. Wavy lines represent binding sites.

The compound represented by formula (b12) is an organic compound having a plurality of thiol groups, like the compound represented by formula (b11). R may have a functional group containing a hetero atom, for example, may have a hetero atom between two or more carbon atoms constituting a hydrocarbon group.

Any functional group containing a heteroatom may be present in R as long as it does not adversely affect reactivity. Examples of the functional group include an ether group, an ester group, a group having a cyclic hydrocarbon structure in which at least one carbon atom is substituted with a heteroatom, a uryl group, a group having a heterocyclic structure, a sulfide group, an amino group, An amide group, a urethane group, a ketone group and the like can be mentioned.

The (e+f)-valent group of R having a linear, branched or cyclic structure having 2 to 28 carbon atoms includes, for example, a hydrocarbon group having 2 to 28 carbon atoms, more specifically includes an aliphatic hydrocarbon group, an aromatic hydrocarbon group and an alicyclic hydrocarbon group.

R is particularly preferably any one of the groups represented by the following formulas (b4) to (b8).

In formulas (b4) to (b8), n represents an integer of 1 to 10. Wavy lines indicate binding sites.

The compound represented by formula (b12) is, for example, an ester of mercaptocarboxylic acid and polyhydric alcohol. By sulfidating a part or all of the thiol groups of the compound with a specific acid anhydride, the acid anhydride represented by formula (B2) can be obtained.

Examples of compounds represented by formulas (b11) and (b12) include trimethylolpropane tris(3-mercaptopropionate) (TMMP manufactured by SC Organic Chemical Co., Ltd.), tris-[(3-mercaptopropionyloxy )-ethyl]-isocyanurate (TMPIC manufactured by SC Organic Chemical Co., Ltd.), pentaerythritol tetrakis(3-mercaptopropionate) (PEMP manufactured by SC Organic Chemical Co., Ltd.), tetraethylene glycol bis(3-mercaptopropionate) (EGMP-4 manufactured by SC Organic Chemical Co., Ltd.) and dipentaerythritol hexakis (3-mercaptopropionate) (DPMP manufactured by SC Organic Chemical Co., Ltd.). Furthermore, pentaerythritol tetrakis (3-mercaptobutyrate), 1,4-bis (3-mercaptobutyryloxy) butane, 1,3,5-tris (3-mercaptobutyrate) sold by Showa Denko K.K. lyloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptobutyrate), trimethylolethane tris(3-mercaptobutyrate) ), pentaerythritol poly(3-mercaptopropionate), 4-(mercaptomethyl)-3,6-dithiaoctane-1,8-dithiol, 4,8-bis(mercapto methyl)-3,6,9-trithiaundecane-1,11-dithiol, 1,3,4,6-tetrakis (2-mercaptoethyl) glycoluril (TS- G) etc. can also be used. Furthermore, ethanedithiol, propanedithiol, butanedithiol, hexamethylenedithiol, decamethylenedithiol, tolylene-2,4-dithiol, xylene dithiol, diglycol dimercaptan, triglycol dimercaptan, polyoxypropylene glycol dimercaptan, tris-[ Known compounds such as (3-mercaptopropionyloxy)-ethyl]-isocyanurate and 1,3,5-trithiopropyl isocyanurate can also be used.

Each substituent of the acid anhydrides represented by formulas (B1) and (B2) was derived from the compounds represented by the above formulas (b9), (b10), (b11), and (b12). structure.

In addition, when multiple types of compounds are used in combination as the compound represented by formula (b9) and the compound represented by formula (b10), Rx of formula (B1) can be a compound having multiple types of structures. . Such compounds are also included in the acid anhydride represented by formula (B1). The same applies to the acid anhydride represented by formula (B2). That is, the acid anhydrides represented by formulas (B1) and (B2) may be used singly or in the form of a mixture of two or more kinds of acid anhydrides.

The compounds represented by formulas (b11) and (b12) have a plurality of thiol groups. By adjusting the molar ratio between the unsaturated group-containing acid anhydride and the thiol groups to be reacted, any proportion of the thiol groups in the raw material can be converted to sulfide groups. In addition, even if the thiol group remains, the remaining thiol group causes a curing reaction with the epoxy group, so it does not adversely affect the effects of the present invention, but rather low-temperature curing by the thiol group. can be expected.

For example, when a compound having six thiol groups is used as the compound represented by the formula (b11), when reacting using 3 mol of an unsaturated group-containing acid anhydride with respect to 1 mol of the thiol compound, 50% of the thiol groups of are substituted with sulfide groups. In this case, 3 of the 6 thiol groups are not only sulfide compounds, but 50% of the thiol groups in the composition as a whole are substituted with sulfide groups. As a result, a mixture of a plurality of compounds differing only in the proportions of a and b in the above formula is obtained. Such mixtures are also part of this invention.

The reaction rate of the thiol group ((number of sulfide groups)/(number of sulfide groups + number of thiol groups) in the acid anhydrides represented by formulas (B1) and (B2) is not particularly limited, but may be, for example, 15 to 100%. Preferably, it is 50 to 70%.

In the mixture, the compounds represented by the formulas (b9), (b10), (b11), and (b12) may remain as unreacted raw materials in some cases. A composition in which raw materials remain is also included in the present invention.

The acid anhydrides represented by the formulas (B1) and (B2) are not particularly limited as long as they have the structures described above, but specific examples of the compounds are shown below.

Acid anhydrides represented by formula (B1) include the following.

Examples of the acid anhydride represented by formula (B2) include the following.

Such a compound is represented by formula (b12), which can be easily produced by an esterification reaction of a mercaptocarboxylic acid such as 3-mercaptopropionic acid or 3-mercaptobutanoic acid and a polyhydric alcohol such as pentaerythritol or trimethylolpropane. It is particularly preferable in that the represented compound is used as a raw material.

The acid anhydride represented by the formula (B1) is mixed with the compound represented by the formula (b9) and/or the compound represented by the formula (b10) and the compound represented by the formula (b11) to obtain an enthiol It can be obtained by a method of forming a sulfide bond through a reaction. Similarly, the acid anhydride represented by formula (B2) is mixed with the compound represented by formula (b9) and/or the compound represented by formula (b10) and the compound represented by formula (b12). and can be obtained by a method of forming a sulfide bond by an enethiol reaction.

A method of forming a sulfide bond by an enethiol reaction is not particularly limited, and examples thereof include a method of ultraviolet irradiation or a radical reaction. A general formula for such a reaction is shown below. However, the acid anhydride represented by formula (B1) is not limited to those synthesized by the following reaction scheme.

An example of the reaction formula for the acid anhydride represented by formula (B2) is shown below.

The ultraviolet irradiation or radical reaction can be carried out in an organic solvent. Examples of the organic solvent include acid anhydrides represented by formula (B1) and/or formula (B2), compounds represented by formula (b9) and/or compounds represented by formula (b10), and formula (b11). and/or is not particularly limited as long as it is an organic solvent in which the formula (b12) is dissolved, and examples thereof include tetrahydrofuran.

The ultraviolet irradiation can also be performed in the presence of the alicyclic epoxy compound (A). In the case of the reaction by ultraviolet irradiation described above, even if an epoxy group is present in the system, the formation reaction of the sulfide group by the unsaturated bond and the thiol group occurs preferentially, so the alicyclic epoxy compound (A) The acid anhydrides represented by the formulas (B1) and (B2) can also be obtained by performing the reaction by ultraviolet irradiation in the presence of these.

When the reaction is carried out in the alicyclic epoxy compound (A), a liquid epoxy compound is preferred because it can serve as a solvent.

[Curing accelerator (C)]
The curable epoxy resin composition of the present invention contains a curing accelerator (C). The curing accelerator (C) is a compound having a function of accelerating the reaction rate when a compound having an epoxy group reacts with a curing agent or the like. As the curing accelerator (C), a known or commonly used curing accelerator can be used. 1,5-diazabicyclo[4.3.0]nonene-5 (DBN) or salts thereof (e.g., phenol salts, octylate, p-toluenesulfonate, formate, tetraphenylborate salt, etc.); class amines; imidazoles such as 2-ethyl-4-methylimidazole and 1-cyanoethyl-2-ethyl-4-methylimidazole; phosphines such as phosphoric acid esters and triphenylphosphine; tetraphenylphosphonium tetra(p-tolyl)borate and the like; organic metal salts such as zinc octylate and tin octylate; and metal chelates.

A hardening accelerator (C) can also be used individually by 1 type, and can also be used in combination of 2 or more types. The curing accelerator (C) can also be produced by a known or commonly used method, for example, trade names "U-CAT SA 506", "U-CAT SA 102", "U-CAT 5003", "U-CAT 18X", "12XD" (development products) (manufactured by San-Apro Co., Ltd.); trade names "TPP-K" and "TPP-MK" (manufactured by Hokko Chemical Industry Co., Ltd.); A commercially available product such as "PX-4ET" (manufactured by Nippon Kagaku Kogyo Co., Ltd.) can also be used.

The content (compounding amount) of the curing accelerator (C) is not particularly limited, but is 0.05 to 10 parts by weight with respect to 100 parts by weight of the total amount of the compound having an epoxy group contained in the curable epoxy resin composition. is preferred, more preferably 0.1 to 5 parts by weight. By setting the content of the curing accelerator to 0.05 parts by weight or more, there is a tendency that the curing reaction can proceed more efficiently. On the other hand, when the content of the curing accelerator is 10 parts by weight or less, coloring tends to be suppressed and a cured product with an excellent hue tends to be obtained.

In the curable epoxy resin composition of the present invention, in addition to the above components, various additives can be used as long as they do not impair the effects of the present invention. As such additives, for example, compounds having a hydroxyl group such as ethylene glycol, diethylene glycol, propylene glycol and glycerin can be used to allow the reaction to proceed slowly. In addition, antifoaming agents, leveling agents, silane coupling agents such as γ-glycidoxypropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane, surfactants and Conventional additives such as flame retardants, colorants, ion adsorbents, ultraviolet absorbers, light stabilizers, and pigments other than white pigments can be used. The content of these additives is not particularly limited and can be selected as appropriate.

Although the curable epoxy resin composition of the present invention is not particularly limited, it can be prepared by stirring and mixing each of the above components in a heated state if necessary. The curable epoxy resin composition of the present invention can be used as a one-liquid composition in which each component is premixed and used as it is. It can also be used as a multi-liquid system (for example, two-liquid system) composition in which the components are mixed in a predetermined ratio before use. The stirring/mixing method is not particularly limited, and known or commonly used stirring/mixing means such as various mixers such as dissolvers and homogenizers, kneaders, rolls, bead mills, and rotation-revolution stirrers can be used. Moreover, after stirring and mixing, defoaming may be performed under vacuum.

As a curing means, known means such as heat treatment can be used. The temperature for curing by heating (curing temperature) is not particularly limited, but is preferably 45 to 200.degree. C., more preferably 50 to 190.degree. C., still more preferably 55 to 180.degree. The time for heating during curing (curing time) is not particularly limited, but is preferably 30 to 600 minutes, more preferably 45 to 540 minutes, and even more preferably 60 to 480 minutes. When the curing temperature and curing time are lower than the lower limit of the above range, the curing becomes insufficient. The curing conditions depend on various conditions, but can be adjusted as appropriate by, for example, shortening the curing time when the curing temperature is raised and lengthening the curing time when the curing temperature is lowered. Moreover, curing can be carried out in one step or in multiple steps of two or more steps.

Furthermore, it contains a compound represented by formula (b9) and/or a compound represented by formula (b10), a compound represented by formula (b11), an epoxy compound (A), and a curing accelerator (C). After molding the composition into a predetermined shape, the compound represented by the formula (b9) and/or the compound represented by the formula (b10) and the compound represented by the formula (b11) are formed by irradiating with ultraviolet rays. A cured product of the epoxy resin composition can also be obtained by forming the curing agent (B) through a reaction, followed by thermal curing.

The curable resin composition of the present invention is preferably used as, for example, a sealant. Among them, it is particularly preferably used as a sealant for optical elements such as LEDs. The encapsulant of the present invention is preferable because the cured product thereof has high transparency, heat resistance and water resistance, and does not cause a decrease in light intensity or a change in color. Furthermore, shrinkage during curing is small, and damage to elements in the production process can be greatly reduced, improving productivity.

The curable resin composition of the present invention has high transparency, low light loss, low curing shrinkage, and high heat resistance, water resistance, and flexibility of the cured product, and is resistant to deterioration and deterioration during long-term use. It is also preferably used as an adhesive from the viewpoint of no coloring. Adhesives are preferably used for, for example, assembly and connection of optical communication devices such as liquid crystal panel components and optical fibers, fixing of various optical components such as optical sensors and optical lenses, and bonding of optical components such as optical lenses and prisms. .

The cured resin product of the present invention is also preferably used as a coating agent for protecting optical parts such as liquid crystal panels. Since the cured product has high transparency, there is no deterioration in image quality, and heat resistance, water resistance, and flexibility are high, which is preferable.

<Cured product>
By curing the curable epoxy resin composition of the present invention, a cured product having excellent physical properties such as heat resistance and water resistance (hereinafter sometimes referred to as "cured product of the present invention") can be obtained. . The heating temperature (curing temperature) for curing is not particularly limited, but is preferably 45 to 200.degree. C., more preferably 50 to 190.degree. C., still more preferably 55 to 180.degree. The time for heating during curing (curing time) is not particularly limited, but is preferably 30 to 600 minutes, more preferably 45 to 540 minutes, and even more preferably 60 to 480 minutes. When the curing temperature and curing time are lower than the lower limit of the above range, the curing becomes insufficient. The curing conditions depend on various conditions, but can be adjusted as appropriate by, for example, shortening the curing time when the curing temperature is raised and lengthening the curing time when the curing temperature is lowered.

The cured product of the present invention has high transparency and light reflectivity, and is also excellent in heat resistance and water resistance. Therefore, the curable epoxy resin composition of the present invention can be used for optical semiconductor encapsulation applications (e.g., LED encapsulant applications) and LED package applications (components of LED packages, e.g., reflector materials and housings in optical semiconductor devices). material, etc.).

In addition to the above, the curable epoxy resin composition and cured product of the present invention can also be Optical lenses, optical members, stereolithography, electronic paper, touch panels, solar cell substrates, optical waveguides, light guide plates, holographic memories, chip parts, bare chip mounting, optical fibers, optical pickup sensors (e.g., DVD recorders, Blue Ray recorders, etc. optical pickup sensor), photoelectric sensor (e.g., photoelectric sensor in contactless switch, etc.), color sensor (e.g., color sensor in camera, printer, etc.), illuminance sensor (e.g., illuminance sensor in mobile terminal, TV, etc.), proximity sensor (e.g., proximity sensors in mobile terminals, etc.), composite sensors (e.g., composite sensors in mobile terminals, etc.), image sensors (e.g., image sensors in cameras, etc.), AF sensors (e.g., AF sensors in cameras, etc.), MEMS mounting It can also be used for various applications such as.

EXAMPLES The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

(Reference example 1)
A reactor was charged with 3.00 g of pentaerythritol tetrakis(3-mercaptopropionate) (PEMP; manufactured by SC Organic Chemical Co., Ltd.) and 7 mL of tetrahydrofuran (THF) and stirred at room temperature. Subsequently, after adding 2.03 g of 5-norbornene-2,3-dicarboxylic anhydride (CPDMA), UV irradiation was performed at a reaction temperature of 60° C. for 10 minutes. After confirming that the reaction was progressing quantitatively by NMR, THF was distilled off under reduced pressure to obtain the target acid anhydride (compound A) as a residue.

FIG. 1 shows the ¹ H-NMR chart of the compound obtained by the reaction of the raw materials PEMP and CPDMA when carrying out Reference Example 1. From FIG. 1, it is observed that the vinylene peak of CPDMA disappears due to the reaction, and it is clear that the desired acid anhydride is obtained.

(Example 1)
According to the formulation (unit: parts by weight) shown in Table 1, Celoxide 2021P (CEL2021P, manufactured by Daicel Corporation), the acid anhydride obtained in Reference Example 1 (Compound A), U-CAT 18X (18X, San-Apro ( Co., Ltd.) and ethylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.) are stirred using a rotation-revolution stirring device (trade name “Awatori Mixer AR-250”, manufactured by Thinky Co., Ltd.). defoamed. The obtained solution was poured into a frame mold, heated at 120° C. for 5 hours, and cured to obtain a cured product of the epoxy resin composition.

(Example 2, Comparative Example 1)
A curable epoxy resin composition and a cured product thereof were obtained in the same manner as in Example 1, except that the composition was changed as shown in Table 1.

<Evaluation>
The cured products obtained in Examples 1 and 2 and Comparative Example 1 were evaluated as follows.

[Cured product-Tg]
A test piece having a size of 5 mm long, 4 mm wide, and 10 mm high was cut out from the cured products obtained in Examples and Comparative Examples, and was measured using a thermomechanical measurement apparatus (TMA) (manufactured by Seiko Instruments Inc.). The glass transition temperature (Tg, unit: °C) of the test piece was measured. The results are shown in the "Tg (°C)" column of Table 1.

[Cured product - transparency]
A test piece having a size of 50 mm long, 30 mm wide, and 3 mm high was cut out from the cured products obtained in Examples and Comparative Examples, and a spectrophotometer (trade name “UV-2400”, manufactured by Shimadzu Corporation) was used. was used to measure the transmittance of the test piece (wavelength: 450 nm, unit: %T). The results are shown in Table 1, "Transparency [%T]" column.

[Cured product - refractive index]
A test piece having a size of 50 mm long, 30 mm wide, and 0.5 mm high was cut out from the cured products obtained in Examples and Comparative Examples, and the test piece was cut using a prism coupler (2010/M) (manufactured by Metricon). A refractive index (wavelength: 589 nm) was measured. The results are shown in the "refractive index" column of Table 1.

[Cured product-curing shrinkage]
The specific gravity a of the curable resin composition in Examples and Comparative Examples was measured using a pycnometer, the specific gravity b of the cured product was measured by the water substitution method, and the cure shrinkage (%) was determined by the following equation. The results are shown in the column of "cure shrinkage (%)" in Table 1.
Cure shrinkage rate (%) = [1-(b/a)] x 100

[Cured product - Comprehensive judgment]
If the cured product has a glass transition temperature of 138°C or higher, a transparency of 85% T or higher, a refractive index of 1.52 or higher, and a curing shrinkage of 3.0% or lower, "O" is given. When not satisfying, it was described in Table 1 as "x".

[Production of optical material (optical semiconductor device)]
After casting the resin composition in Examples and Comparative Examples into a lead frame (InGaN element, 3.5 mm × 2.8 mm) of an optical semiconductor, the resin composition was heated in an oven at 120 ° C. for 5 hours. An optical semiconductor device in which an optical semiconductor element was sealed with the cured product of (see FIG. 2) was obtained. The transparency (brightness) and heat resistance of the obtained optical semiconductor device were evaluated. In FIG. 2, 100 is a reflector (light reflecting resin composition), 101 is a metal wiring, 102 is an optical semiconductor element, and 103 is a package substrate.

[Optical Materials - Transparency (Brightness)]
The transparency (brightness) (lumen: lm) of the optical semiconductor device was measured by measuring the total luminous flux of the optical semiconductor device using a total luminous flux measuring machine (trade name “Multi-spectral radiation measurement system OL771”, manufactured by Optronic Laboratories). It was measured. The results are shown in the "transparency (lm)" column of Table 1.

[Optical Materials - Heat Resistance]
The optical semiconductor device was subjected to heat treatment (aging) at 120° C. for 300 hours, and the light transmittance retention rate was calculated from the following formula and used as an index of heat resistance. The results are shown in the column of "heat resistance (%)" in Table 1.
Light transmittance retention (%)=(light transmittance of optical semiconductor device after heat treatment/light transmittance of optical semiconductor device before heat treatment)×100

[Optical materials - Comprehensive judgment]
If the transparency of the optical semiconductor device was 0.60 lm or more and the heat resistance was 80% or more, it was described as "O", and if even one of these conditions was not satisfied, it was described as "X".

[Coating agent - reactivity]
The reactivity of the resin compositions (coating agents) in Examples and Comparative Examples was measured using a gel time measuring device (trade name “No. 153 Gel Time Tester (magnet type)”, manufactured by Yasuda Seiki Seisakusho Co., Ltd.). In addition, the reactivity (curing property; gel time) when heated at 120° C. was evaluated. The results are shown in the "reactivity (sec)" column of Table 1.

[Coating agent - thermal shock test]
The cured products in Examples and Comparative Examples were exposed to an atmosphere of −40° C. for 30 minutes and then exposed to an atmosphere of 100° C. for 30 minutes. was given for 200 cycles. After that, the cured product was observed using a digital microscope (trade name “VHX-900”, manufactured by Keyence Corporation) to confirm whether or not cracks having a length of 90 μm or more occurred. The number of cracks having a length of 90 μm or more generated in the cured product is shown in the column of “thermal shock test [number of cracks]” in Table 1.

[Coating agent - Comprehensive judgment]
If the reactivity of the resin composition (coating agent) is 250 sec or less, and the number of cracks in the thermal shock resistance test of the cured product is 5 or less, "O" will be given. It was described in Table 1.

100: Reflector (resin composition for light reflection)
101: Metal wiring 102: Optical semiconductor element 103: Package substrate

By curing the curable epoxy resin composition of the present invention, a cured product having high heat resistance, water resistance and flexibility can be obtained. Therefore, the resin composition can be used as a sealing agent, an adhesive and a coating agent. Moreover, the cured product can be used as an optical member.

Claims (9)

A curable epoxy resin composition containing an alicyclic epoxy compound (A), a curing agent (B), and a curing accelerator (C),
Curing agent (B) is represented by the following formula (B1)

[Wherein, Rx is the same or different, a hydrogen atom, the following formula (b1)

(R ₁ to R ₆ are the same or different and represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. A wavy line represents a bonding site.)
A group having a structure represented by the following formula (b2)

(R ₇ to R ₁₀ are the same or different and represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. Wavy lines represent bonding sites.)
is a group having a structure represented by formula (b1) or (b2). A is an a-valent linear or branched hydrocarbon group having 2 to 50 carbon atoms which may have a group having a cyclic hydrocarbon structure as a substituent . a represents an integer of 2 to 6; ]
and an acid anhydride represented by the following formula (B2)

[Wherein, Rx is the same or different, a hydrogen atom, the following formula (b1)

(R ₁ to R ₆ are the same or different and represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. A wavy line represents a bonding site.)
A group having a structure represented by the following formula (b2)

(R ₇ to R ₁₀ are the same or different and represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. Wavy lines represent bonding sites.)
is a group having a structure represented by formula (b1) or (b2). Rs are the same or different and are a hydrogen atom or a methyl group. R is a (b+c)-valent group having a linear, branched or cyclic structure and having 2 to 28 carbon atoms, which may have a functional group containing a heteroatom. R' is the same or different and is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a thiol group, or the following formula (b3)

(In the formula, R ₁₁ and R ₁₂ are different, R ₁₁ represents a thiol group or a methyl group, R ₁₂ represents a hydrogen atom or a thiol group, and the wavy line represents a binding site.)
represents a group represented by b and c are such that b+c=2-6, b is an integer including 0, and c is an integer of 1-6. ]
A curable epoxy resin composition characterized by being at least one selected from the group consisting of acid anhydrides represented by: R in the acid anhydride represented by the formula (B2) is represented by the following formulas (b4) to (b8)

(In the formula, n represents an integer of 1 to 10. A wavy line represents a binding site.)
The curable epoxy resin composition according to claim 1, which is any one of the groups represented by: 3. The curable epoxy resin composition according to claim 1, wherein the alicyclic epoxy group of said alicyclic epoxy compound (A) is a cyclohexene oxide group. The alicyclic epoxy compound (A) has the following formula (I-1)

The curable epoxy resin composition according to any one of claims 1 to 3, which is a compound represented by A cured product of the curable epoxy resin composition according to any one of claims 1 to 4. A sealant comprising the curable epoxy resin composition according to any one of claims 1 to 4. An adhesive comprising the curable epoxy resin composition according to any one of claims 1 to 4. A coating agent comprising the curable epoxy resin composition according to any one of claims 1 to 4. An optical member comprising the cured product according to claim 5 .

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