JP2011046823A - Epoxy resin and epoxy resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin having low viscosity, low discoloration, and excellent reactivity; and an epoxy resin cured product with excellent heat resistance, light transmittance, light resistance, and crack resistance. <P>SOLUTION: An epoxy resin (A) represented by general formula (1); an epoxy resin composition containing the epoxy resin and a curing agent (H1) and/or a curing catalyst (H2); and a cured product obtained from the epoxy resin composition are provided, wherein OR<SP>1</SP>is an oxyalkylene group and R<SP>1</SP>is a 1-20C straight chain or branched alkylene group; and n is 0 or an integer of 1-10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a novel epoxy resin, an epoxy resin composition and a cured product thereof. More specifically, the present invention relates to an epoxy resin having a specific alicyclic structure, an epoxy resin composition containing the epoxy resin, and a cured product thereof.

Conventionally, epoxy resins are widely used in the fields of electrical and electronic fields such as casting, sealing, and laminates, as well as fields such as adhesives, paints, and composite materials. In particular, liquid epoxy resins have excellent workability at room temperature, and are therefore suitably used as anticorrosive coating materials for buildings, casting materials, and liquid sealing materials.
Among them, a transparent epoxy resin having excellent light resistance is expected to be used as a sealing material for optical semiconductors, an optical material, a coating material, an adhesive for optical components, and the like.

For example, a well-known bisphenol type epoxy resin is widely used because it is a colorless and transparent liquid at room temperature and can be easily mixed with a curing agent, an additive, or the like (Patent Document 1).
However, it has a high viscosity for use in recent miniaturized or thin electronic parts, causing molding defects such as the resin not completely filling the minute gaps between the parts or entraining bubbles, resulting in poor insulation and moisture resistance. There is a problem of causing deterioration.
In addition, aromatic (bisphenol type) epoxy resins are at a low level in terms of light resistance, such as being discolored by ultraviolet rays, and are limited in use as optical resins such as sealants for optical elements and outdoors.

Therefore, light resistance is improved by using a hydrogenated epoxy resin obtained by nuclear hydrogenation of an aromatic epoxy resin (Patent Document 2).
However, hydrogenated epoxy resins have low heat resistance and are insufficient in terms of viscosity. Furthermore, since bisphenol type and hydrogenated epoxy resins are obtained by glycidylation reaction using epichlorohydrin, the by-product chlorine impurities cause the heat resistance and light resistance of the cured product to deteriorate. It has become. Moreover, these epoxy resins have a problem of low reactivity with acids in acid anhydride curing agents and cationic curing reactions.

On the other hand, an alicyclic epoxy resin having a 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate structure is known as an epoxy resin having low viscosity, high heat resistance, and high light resistance. (Non-Patent Document 1).
However, the alicyclic epoxy resins described in the above documents do not have sufficient crack resistance.
In addition, many of these alicyclic epoxy resins cannot be used because of their slow reaction with amine-based curing agents and phenol-based curing agents.

  That is, there is no conventional epoxy resin that satisfies all the required performance of low viscosity, heat resistance, light resistance, crack resistance and high reactivity, and a liquid new epoxy resin that satisfies these requirements has been desired. .

Japanese Patent Laid-Open No. 06-041395 JP 2005-120357 A

"Epoxy Resin Handbook" (Masaki Shinbo al., Nikkan Kogyo Shimbun 1987 issue) from 77 to 87 pages

  An object of the present invention is to provide an epoxy resin having low viscosity, little coloring, and excellent reactivity; and an epoxy resin cured product excellent in any of heat resistance, light transmittance, light resistance, and crack resistance. It is.

The inventors of the present invention have reached the present invention as a result of studies to achieve the above object.
That is, the present invention provides an epoxy resin represented by the general formula (1) or (2); an epoxy resin composition further containing a curing agent (H1) and / or a curing catalyst (H2) in these epoxy resins; It is a cured product obtained from this epoxy resin composition.

Wherein ^{(1), R} 1 OR 1 is an oxyalkylene group is a straight-chain or alkylene group branched having 1 to 20 carbon atoms; represents an n is an integer of 0 or 1 to 10. ]

[In formula (2), ^{R 2} represents a linear or branched alkylene group having 1 to 20 carbon atoms. ]

  The epoxy resin of the present invention has low viscosity, little coloration, and excellent reactivity. Furthermore, when the epoxy resin of this invention is used, the epoxy resin hardened | cured material which is excellent in all of heat resistance, light transmittance, light resistance, and crack resistance is obtained.

The epoxy resin of this invention is 2 types, the epoxy resin (A) represented by the following general formula (1), and the epoxy resin (B) represented by the below-mentioned general formula (2).
The epoxy resin (A) of the first invention of the present invention is represented by the following general formula (1).

Wherein ^{(1), R} 1 OR 1 is an oxyalkylene group is a straight-chain or alkylene group branched having 1 to 20 carbon atoms; represents an n is an integer of 0 or 1 to 10. ]

In the general formula (1) representing the epoxy resin (A) of the present invention, OR ¹ is an oxyalkylene group and R ¹ is an alkylene group having 1 to 20 carbon atoms, which may be linear or branched. .
N represents 0 or an integer of 1 to 10.

  In the general formula (1), when n is 0, the two cyclohexane rings are bonded with a divalent oxygen atom.

In the general formula (1), when n is 1, a divalent group that connects two cyclohexane rings is represented by —OR ¹ O—. R ^{1 in} —OR ¹ O— represents a linear alkylene group having 1 to 20 carbon atoms, a branched alkylene group having 3 to 20 carbon atoms, carbon number (the number of carbon atoms of the alkyl substituent bonded to the ring). 4-20 cycloalkylene groups.

  Examples of the linear alkylene group having 1 to 20 carbon atoms include methylene group, ethylene group, propylene group, isopropylene group, butylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene group, and decylene. Group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene group, octadecylene group, nonadecylene group, eicosylene group and the like.

  Examples of the branched alkylene group having 2 to 20 carbon atoms include methylmethylene group, isopropylene group, isobutylene group, 2,2-dimethylpropylene group, 2,3-dimethylbutylene group, 2-cyclohexylheptylene group, 2 , 4-6-triethylnonylene group, 2-ethylhexylene group, and the like.

  Examples of the cycloalkylene group having 4 to 20 carbon atoms include cyclobutylene group, cyclopentylene group, 2-methylcyclopentylene group, cyclohexylene group, 1,3-dimethylcyclohexylene group, cycloheptylene group and 1-ethylcyclopentylene. Len group, cyclooctylene group, cyclononylene group, cyclodecylene group, cycloundecylene group, cyclododecylene group, cyclotridecylene group, cyclotetradecylene group, cyclopentadecylene group, cyclohexadecylene group, cycloheptadecylene group, cyclo An octadecylene group, a cyclononadecylene group, a cycloeicosylene group, a norbornylene group, a dicyclopentylene group, an isopropylidene dicyclohexylene group, a cyclohexanedimethylene group, and the like are represented.

When n is 1, preferred examples of R ¹ in —OR ¹ O— include a linear alkylene group having 2 to 10 carbon atoms, a branched alkylene group having 3 to 10 carbon atoms, or 6 to 6 carbon atoms. 15 cycloalkylene groups.
More preferably, ethylene group, propylene group, 1-methylethylene group, 1-methylpropylene group, 2,2-dimethyl-propylene group, butylene group, 1,3-dimethyl-propylene group, 3,3-dimethyl-pentylene. Group, 2-ethyl-hexylene group, cyclohexylene group, methylcyclohexylene group, isopropylidene dicyclohexylene, and cyclohexanedimethylene group.

In the general formula (1), when n is 2 to 10, a divalent group that connects two cyclohexane rings is represented by — (OR ¹ ) _n O—.
R ^{1 in} — (OR ¹ ) _n O— is a linear alkylene group having 1 to 6 carbon atoms, a branched alkylene group having 3 to 8 carbon atoms, or an alkyl bonded to a ring having 4 to 10 carbon atoms. Including the carbon number of the substituent). Each R ¹ may be the same or different.

  Examples of the linear alkylene group having 1 to 6 carbon atoms include an ethylene group, a propylene group, a butylene group, a pentylene group, and a hexylene group.

  Examples of the branched alkylene group having 3 to 8 carbon atoms include a methylmethylene group, an isopropylene group, an isobutylene group, a 2,2-dimethylpropylene group, and a 2,3-dimethylbutylene group.

  Examples of the cycloalkylene group having 4 to 10 carbon atoms include cyclobutylene group, cyclopentylene group, 2-methylcyclopentylene group, cyclohexylene group, 1,3-dimethylcyclohexylene group, cycloheptylene group, and 1-ethylcyclopentylene. Examples include a len group and a cyclooctylene group.

Preferred examples of R ¹ in — (OR ¹ ) nO— include a linear alkylene group having 2 to 5 carbon atoms, a branched alkylene group having 3 to 8 carbon atoms, and a cycloalkylene having 6 to 8 carbon atoms. It is a group.

  Specific examples of the epoxy resin (A) include bis (4-epoxy-1 (2) cyclohexyl) ether, 1,2-ethylene glycol bis (4-epoxy-1 (2) -cyclohexyl) ether, 1,2- Propylene glycol-bis (4-epoxy-1 (2) -cyclohexyl) ether, 1,4-butylene glycol-bis (4-epoxy-1 (2) -cyclohexyl) ether, 1,5-pentylene glycol-bis ( 4-epoxy-1 (2) -cyclohexyl) ether, 2-ethylhexylene glycol-bis (4-epoxy-1 (2) -cyclohexyl) ether, 2,2-dimethyl-1,3-propylene glycol bis (4 -Epoxy- (2) -cyclohexyl) ether, 1,6-cyclohexanediol bis (4-epoxy- (2) -cyclohexyl) ether, 4,4′-hydroxy-isopropylidenedicyclohexyl-bis (4-epoxy-1 (2) cyclohexyl) ether, diethylene glycol- (4-epoxy-1 (2) -cyclohexyl) ether, di Propylene glycol- (4-epoxy-1 (2) -cyclohexyl) ether, cyclohexanedimethanol- (4-epoxy-1 (2) -cyclohexyl) ether, polypropylene glycol- (4-epoxy-1 (2) -cyclohexyl) Examples include ether.

  From the viewpoint of heat resistance, bis (4-epoxy-1 (2) cyclohexyl) ether, 1,2-ethylene glycol-bis (4-epoxy-1 (2) -cyclohexyl) ether, 1,3-propylene glycol-bis (4-epoxy-1 (2) -cyclohexyl) ether, 1,4-butylene glycol-bis (4-epoxy-1 (2) -cyclohexyl) ether, 2,2-dimethyl-1,3-propylene glycol bis ( 4-epoxy-1 (2) -cyclohexyl) ether, 1,6-cyclohexanediol (4-epoxy-1 (2) -cyclohexyl) ether, dipropylene glycol (4-epoxy-1 (2) -cyclohexyl) ether and 1,6-cyclohexanediol bis (4-epoxy-1 (2) -cyclohexyl) Ether, 4,4'-hydroxy - isopropylidene dicyclohexyl - bis (4-epoxy-1 (2) cyclohexyl) ether, cyclohexanedimethanol - (4- Epoxy -1 (2) - cyclohexyl) ether.

As a typical production method of the epoxy resin (A) of the present invention, the following three production methods (1) to (3) are exemplified, but the production method is not particularly limited thereto.
Production method (1): In the presence of a metal catalyst, an unsaturated compound (C) represented by the following general formula (3), or a solution containing the compound, hydrogen peroxide, organic peroxide, inorganic peroxide, etc. A method of oxidizing with an oxidizing agent.

[Wherein, OR ¹ represents an oxyalkylene group, and R ¹ represents a linear or branched alkylene group having 1 to 20 carbon atoms. n represents 0 or an integer of 1 to 10. ]

  Production method (2): A method in which the unsaturated compound (C) is oxidized with only an oxidizing agent such as hydrogen peroxide, organic peroxide, or inorganic peroxide without the presence of a catalyst.

  Production method (3): A method of oxidizing the unsaturated compound (C) using a metal catalyst and molecular oxygen.

Of these, the production method (1) and the production method (2) are preferred, and the production method (1) is more preferred.
Among the production methods (1), the case where hydrogen peroxide is used as an oxidizing agent is preferable. The most preferred combination is when hydrogen peroxide is used as an oxidizing agent and is easy to handle, and a heteropolyacid catalyst or a silica titania catalyst is used as a metal catalyst, which oxidizes unsaturated groups with high selectivity. In addition, the by-product is few and the obtained epoxy resin has a good hue.

Below, a manufacturing method (1) is explained in full detail.
In the unsaturated compound (C) represented by the above general formula (3) as a raw material in the production method (1), the epoxy group in the general formula (1) representing the epoxy resin (A) is replaced with a vinyl group. It is a compound of a given chemical structure. Examples of the unsaturated compound (C) as a raw material include 1,2-ethylene glycol bis (4-vinyl-1 (2) -cyclohexyl) ether, 1,3-propylene glycol-bis (4-vinyl-1 ( 2) -Cyclohexyl) ether, 1,4-butylene glycol-bis (4-vinyl-1 (2) -cyclohexyl) ether, 2,2-dimethyl-1,3-propylene glycol bis (4-vinyl-1 (2 ) -Cyclohexyl) ether, 1,6-cyclohexanediol (4-vinyl-1 (2) -cyclohexyl) ether, 4,4′-hydroxy-isopropylidenedicyclohexyl-bis (4-vinyl-1 (2) cyclohexyl) ether Dipropylene glycol (4-vinyl-1 (2) -cyclohexyl) ether, cyclohexanedi And methanol- (4-vinyl-1 (2) -cyclohexyl) ether.

As the production method of the unsaturated compound (C), a method of etherifying by adding a proton of alkylene glycol to a double bond of cyclohexene ring of 4-vinyl-1-cyclohexene under an acid catalyst, 4-vinyl-1 Examples include a method of dehydrating cyclohexanol and alkylene glycol under reduced pressure in the presence of an acid catalyst and etherifying, and a method of dehydrohalogenating 4-ether-1-cyclohexanol and dihaloalkane to etherify.
The reaction conditions for these etherification reactions are described in, for example, Japanese Patent Application Laid-Open No. 5-263188, and the acid catalyst includes boron trifluoride / THF complex, boron trifluoride diethyl ether complex, aluminum trichloride. Can use Lewis acid such as Lewis acid, heteropolyacid, solid proton acid such as benzene sulfonic acid, etc., solid acid such as metallosilicate, strong acid cation exchange resin, etc. The reaction temperature uses the former Lewis acid or strong proton acid In the case, 40-160 degreeC is preferable, and when using the latter solid acid, 100-180 degreeC is preferable.

  The metal catalyst used in the preparation process (1), the heteropoly acid catalyst, metal oxide catalyst, and a metal complex catalyst.

The heteropolyacid catalyst, heteropolyacid catalyst having a ^{_{Q m + [XM 10 O 35}} ] + heteropolyacid catalyst or ^{Q m} represented by ^m- _[XM 10 _{O 35]} ^m- with two defective structure represented the like. Where Q is proton or alkali metal, alkaline earth metal, copper, gold, gallium, ammonium, imidazolium and phosphonium. X is one element selected from P, Si, and Ge, and M is one element selected from W, Mo, and V. m is a positive integer.
The heteropolyacid catalyst having a deficient structure is one or two selected from transition metal elements or rare earth elements of groups 4, 5, 6, 7, 9, 10 of the periodic table in the deficient part. The metal elements are arranged.

  Examples of the metal oxide catalyst include titanium oxide, magnesium oxide, cesium oxide, silver oxide, titanium silicalite, and montmorillonite.

  Examples of the metal complex catalyst include vanadyl acetylacetonate, cobalt acetylacetonate, manganese sulfate, and methyltrioxorhenium.

Of the metal catalysts used in the production method (1), preferred are heteropolyacid catalysts, and more preferred are tungstic acid and tungstate where M is tungsten. Particularly preferably, tungstic acid (H ₂ WO ₄ ), silicotungstic acid (H ₄ [SiW ₁₂ O ₄₀ ] .xH ₂ O), phosphotungstic acid (H ₃ [PW ₁₂ O ₄₀ ] .xH ₂ O) and the above-mentioned Examples thereof include sodium salt, potassium salt, barium salt, cesium salt, calcium salt, ammonium and the like of “particularly preferred tungstic acid”.

The metal catalyst is used in an amount of 0.001 equivalents to 0.1 equivalents, preferably 0.01 equivalents to 0.05 equivalents, based on the double bond.
The metal catalysts may be used alone or in combination.

In the production method (1), essential oxidants are hydrogen peroxide, organic peroxides, and inorganic peroxides.
Hydrogen peroxide is preferably used as 1 to 60% by weight of hydrogen peroxide water.
Examples of the organic peroxide include perbenzoic acid, performic acid, perphthalic acid, perpropionic acid, peracetic acid, and trifluoroperacetic acid.
Examples of the inorganic peroxide include lithium peroxide, potassium peroxide, sodium peroxide, magnesium peroxide, calcium peroxide, and barium peroxide.
Of these oxidizing agents, hydrogen peroxide is preferable from the viewpoint of safety and environment.

In the production method (1), in addition to the metal catalyst and the oxidizing agent, a phase transfer catalyst may be used in combination in order to further improve the reaction yield.
Examples of the phase transfer catalyst include quaternary ammonium salts and quaternary phosphonium salts.

  The quaternary ammonium salt includes a tetraalkylammonium halide, a benzyltrialkylammonium halide, a tetraalkylammonium phosphate hydrogenated, a benzyltrialkylammonium phosphate hydrogenated, a sulfuric acid having an alkyl group having 1 to 18 carbon atoms. Examples thereof include tetraalkylammonium hydride and benzyltrialkylammonium hydrogensulfate.

  Examples of the quaternary phosphonium salt include, for example, a tetraalkylphosphonium halide, a tetraphenylphosphonium halide, a tetraalkylphosphonium hydrogen phosphate, a tetraalkylphosphonium hydrogen phosphate, a hydrogenated tetraphenylphosphonium phosphate, and a hydrogen sulfate. Tetraalkylphosphonium hydride and tetraphenylphosphonium hydrogensulfate.

  Among these phase transfer catalysts, preferred are trioctylmethylammonium hydrogen sulfate, dilauryldimethylammonium hydrogensulfate, lauryltrimethylammonium hydrogensulfate, stearyltrimethylammonium hydrogensulfate, hydrogensulfate hydrogensulfate from the viewpoint of reaction rate. Lauryldimethylbenzylammonium sulfate, stearyldimethylammonium sulfate, tricaprylmethylammonium sulfate, didecyldimethylammonium sulfate, tetrabutylammonium sulfate, benzyltrimethylammonium sulfate, and benzyltriethylammonium sulfate is there.

  In the production method (1), each raw material may be charged all at once into the system, or any two or more may be mixed and the mixture may be charged into the system. They may be dripped.

The oxidation reaction may be performed in the presence or absence of a solvent.
The solvent can be appropriately selected depending on the type of organic substrate and target product, its solubility, boiling point, and the like. Examples of the solvent include aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, ketones, amides, nitriles, and chain or cyclic ethers used in ordinary chemical reactions. These solvents are used alone or in combination of two or more.

  The oxidation reaction temperature can be appropriately selected in consideration of the reaction rate and reaction selectivity according to the reaction substrate, the type of reaction, and the like, but is, for example, about 0 to 100 ° C., preferably about 50 to 80 ° C. The reaction may be carried out at normal pressure or under pressure. The reaction may be performed by any method such as a batch method, a semi-batch method, or a continuous method.

  The compound obtained by the oxidation reaction is purified and separated by a usual method such as extraction, liquid separation, filtration, centrifugation and / or distillation. Since the oxidation reaction catalyst in the production method (1) has high solubility in water and low solubility in a hydrophobic organic solvent, a method based on extraction, liquid separation, adsorption and filtration is preferred. Particularly preferred is a method in which water is washed with an alkaline aqueous solution and then separated, and impurities in the organic phase are adsorbed with an adsorbent and filtered. As the alkaline aqueous solution, an aqueous solution of 5 to 50% by weight of sodium hydroxide or potassium hydroxide can be used. Examples of the adsorbent include alumina and silica.

  The production method (1), it is possible to produce a high yield of a colorless transparent epoxy resin (A) in a relatively easy process.

  The epoxy resin (B) of the second invention of the present invention is represented by the following general formula (2).

[In formula (2), ^{R 2} represents a linear or branched alkylene group having 1 to 20 carbon atoms. ]

In the general formula (2) representing the epoxy resin (B) of the present invention, R ² is an alkylene group having 1 to 20 carbon atoms and may be linear or branched.

Examples of R ² include the same alkylene groups exemplified in the description of R ¹ in the general formula (1).

Preferable examples of R ² include a linear alkylene group having 2 to 10 carbon atoms, a branched alkylene group having 3 to 10 carbon atoms, and a cycloalkylene group having 6 to 15 carbon atoms.

  Specific examples of the epoxy resin (B) include ethylene-bis (4-epoxy-1 (2) -cyclohexyl), propylene-bis (4-epoxy-1 (2) -cyclohexyl), butylene-bis (4-epoxy -1 (2) -cyclohexyl), pentylene-bis (4-epoxy-1 (2) -cyclohexyl), 2-ethylhexylene-bis (4-epoxy-1 (2) -cyclohexyl), 2,2-dimethyl -1,3-propylene bis (4-epoxy- (2) -cyclohexyl), cyclohexylene bis (4-epoxy-1 (2) -cyclohexyl) and the like.

  From the viewpoint of heat resistance, ethylene-bis (4-epoxy-1 (2) -cyclohexyl), propylene-bis (4-epoxy-1 (2) -cyclohexyl), butylene-bis (4-epoxy-1 (2) -Cyclohexyl), 2,2-dimethyl-1,3-propylenebis (4-epoxy-1 (2) -cyclohexyl), cyclohexylene (4-epoxy-1 (2) -cyclohexyl), 2-ethyl-hexylene ( 4-Epoxy-1 (2) -cyclohexyl) is preferred.

  As a manufacturing method of the epoxy resin (B) of the present invention, in the description of the manufacturing method (1) to manufacturing method (3) of the epoxy resin (A), the following general formula (C) is used instead of the unsaturated compound (C). Examples thereof include a method of subjecting the vinyl group to an oxidation reaction using the unsaturated compound (D) represented by 4) as a raw material.

Wherein (4), ^{R 2} represents a linear or branched alkylene group having 1 to 20 carbon atoms. ]

  In the unsaturated compound (D) represented by the general formula (4) as a raw material in the production method (1), the epoxy group in the general formula (2) representing the epoxy resin (B) is replaced with a vinyl group. It is a compound of chemical structure. Examples of the unsaturated compound (D) as a raw material include ethylene-bis (4-vinyl-1 (2) -cyclohexyl), propylene-bis (4-vinyl-1 (2) -cyclohexyl), butylene-bis ( 4-vinyl-1 (2) -cyclohexyl), 2,2-dimethyl-1,3-propylenebis (4-vinyl-1 (2) -cyclohexyl), cyclohexylene (4-vinyl-1 (2) -cyclohexyl) ), 2-ethyl-hexylene (4-vinyl-1 (2) -cyclohexyl) and the like.

  As a method for producing the unsaturated compound (D), there is a cross-coupling reaction between an organohalogen compound and an organometallic compound. For example, bromination of a double bond of a cyclo ring of 4-vinylcyclohexene is performed, and magnesium is used to form an organic compound. A method of reacting with a dihaloalkane after the Grignard compound, which is a metal compound, is mentioned.

  The reaction conditions for these alkylation reactions are described, for example, in JP-A No. 2003-26612. As the organometallic compound, lithium, magnesium, aluminum, gallium, indium, zinc, zirconium, boron, Silicon, tin, bismuth, etc. can be used. The reaction temperature of the organic metal compound is preferably -20 to 100 ° C., a reaction temperature of dihaloalkane is preferably 0 to 100 ° C..

  Epoxy resins of the present invention is colored with low viscosity is small, excellent homopolymerization due reactivity and curing catalyst with various curing agents.

  The epoxy resin composition of the present invention is an epoxy resin composition containing the epoxy resin (A) or (B) and a curing agent (H1) and / or a curing catalyst (H2).

That is, when the epoxy resin composition contains (1) the epoxy resin (A) or (B), a curing agent (H1), and a curing catalyst (H2), (2) the epoxy resin (A) or (B ) And a curing agent (H1), (3) a case of containing the epoxy resin (A) or (B) and a curing catalyst (H2).
In the case of (1), the combination of the normal hardening | curing agent for epoxy resins, and a hardening accelerator is mentioned.
In the case of (2), there may be mentioned a case where an amine curing agent or imidazole having a catalytic effect is used as the curing agent (H1).
In the case of (3), a case where a photocationic polymerization initiator and a thermal cationic polymerization initiator are used as the curing catalyst (H2) can be mentioned.

  Examples of the curing agent (H1) include ordinary curing agents for epoxy resins, such as amine curing agents, carboxylic acid curing agents, basic active hydrogen compounds, imidazoles, polymercaptan curing agents, phenol resins, ureas. Examples thereof include resins, melamine resins, and latent curing agents.

  Examples of amine curing agents include polymethylenediamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine; mensendiamine, isophoronediamine, bis (4-amino-3-methylcyclohexyl) methane, and N-aminoethyl. And cycloaliphatic polyamines such as piperazine and diaminodicyclohexylmethane; aliphatic polyamines containing aromatic rings such as metaxylylenediamine; aromatic polyamines; amine adducts (polyamine epoxy resin adducts); and ketimines.

  Carboxylic acid curing agents include polycarboxylic acid curing agents such as adipic acid; and phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl anhydride Examples include acid anhydride curing agents such as highmic acid, nadic anhydride, and trimellitic anhydride.

  Examples of the basic active hydrogen compound include dicyandiamide and organic acid dihydrazide. Examples of imidazoles include 2-methylimidazole. Examples of the polymercaptan curing agent, polyhydric phenols, and latent curing agent include those described in JP-A-2007-262204. One or more of these curing agents (H1) can be mixed and used in the epoxy resin composition of the present invention.

  Among the curing agents (H1), from the viewpoint of transparency, acid anhydride curing agents are preferable, and tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride are more preferable.

  In the epoxy resin composition of the present invention, the curing agent (H1) is usually in a blending ratio of 0.5 to 3 equivalent parts with respect to the epoxy group.

  Examples of the curing catalyst (H2) include curing accelerators, photocationic polymerization initiators, and thermal cationic polymerization initiators that are used in ordinary epoxy resins.

  Examples of the curing accelerator include amines, imidazoles, organic phosphines, and Lewis acids. Photocationic polymerization initiators and thermal cationic polymerization initiators include onium salts having hydrocarbon groups, allene-ion complexes, silanols or phenols / chelate compounds catalysts, sulfonate esters and imide sulfonates, and others. The thing of public pamphlet WO2005-090325 is mentioned.

  Moreover, a curing catalyst (H2) is a mixture ratio of 0.2-5 weight part normally with respect to 100 weight part of epoxy resins.

  The epoxy resin composition of the present invention may further contain other additives. Other additives include inorganic fillers, pigments, refractory agents, thixotropic agents, fluidity improvers, mold release agents (such as carnauba wax and OP wax), and coupling agents (γ-glycidoxypropyltrimethoxy). Silane, etc.), colorants (carbon black, etc.), flame retardants (antimony trioxide, etc.), low stress agents (silicon oil, etc.), lubricants (calcium stearate, etc.), etc. can be used.

Moreover, you may use together with the epoxy resin composition the normal epoxy resin which has 2 or more of epoxy groups in a molecule | numerator other than the epoxy resin of this invention.
Examples include: diglycidyl ethers of dihydric phenols such as bisphenol A, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone and resorcin; Polyglycidyl ethers of the above phenols, for example, polyglycidyl ethers such as tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol novolak and o-cresol novolak As well as glycidyl ethers of halogenated bisphenols such as tetrabromobisphenol A; These normal epoxy resins can be used alone or in combination of two or more.
The compounding quantity of the epoxy resin (A) in the epoxy resin composition of this invention is 50-100 weight% in the whole epoxy resin, Preferably it is 70-100 weight%, More preferably, it is the range of 90-100 weight%.

The cured epoxy resin of the present invention is a cured epoxy resin obtained by curing an epoxy resin composition containing a curing agent (H1) and a curing catalyst (H2).
Examples of the energy source for the curing reaction include heating or light irradiation.
As a method for obtaining a cured product, methods such as transfer molding, compression molding, casting, and coating and dipping are used, and the temperature at the time of heat curing is usually in the range of 50 to 230 ° C.

The cured epoxy resin of the present invention is excellent in light transmittance, and the total light transmittance is usually 80% or more, preferably 90% or more, more preferably 95% or more.
In order to make a cured product having an excellent total light transmittance, it is preferable to use an acid anhydride curing agent or an alicyclic amine which is a curing agent having a low color number. Furthermore, in order to suppress coloring during the curing reaction, curing may be performed in a nitrogen atmosphere, or the curing temperature may be lowered as much as possible, and an antioxidant may be added.

  The cured product obtained by curing the epoxy resin of the present invention is excellent in heat resistance, light transmittance, light resistance, and crack resistance, so that it is used for automotive electronic, electrical peripheral materials, outdoor moldings, and light emitting devices with severe thermal environments. It is suitably used as a sealing agent.

The method for measuring the total light transmittance in Examples and Comparative Examples described later is as follows.
<Measurement method of total light transmittance>
A gap of 1 mm was formed between two glass plates (size: 40 mm × 20 mm) using a spacer to form a mold.
The epoxy resin compound was cast into this and cured at 120 ° C. for 3 hours and further at 160 ° C. for 5 hours. The cured product was taken out from the mold and used as a test piece.
Using this cured | curing material piece, based on JISK7361 (1997), the total light transmittance was measured.

According to the present invention described in detail above, it is possible to obtain an epoxy resin having a low viscosity, little coloring, and excellent reactivity. Furthermore, a composition containing the epoxy resin of the present invention and a cured product obtained by curing the epoxy resin and excellent in heat resistance, light transmission, light resistance and crack resistance can be obtained.

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, unless otherwise specified, “%” represents “% by weight” and “parts” represents “parts by weight”.

[Production Example 1] <Production of raw material unsaturated compound (C-1)>
540 parts (5 mol parts) of "VCH"(4-vinylcyclohexene; manufactured by San Petrochemical Co., Ltd.) and 450 parts (7.5 mol parts) of acetic acid are added to a reaction vessel equipped with a stirrer, a temperature controller and a condenser. And heated to 100 ° C. After aging for 8 hours, the mixture was cooled to 60 ° C., added with 300 parts of water, allowed to stand for 1 hour and then separated to remove excess acetic acid. Furthermore, the pressure was reduced to 130 Pa at 40 ° C. to remove unreacted VCH, and 438 parts (2.6 mol parts) of 4-vinylcyclohexyl acetate was obtained.
Further, 205 parts of 35% aqueous sodium hydroxide solution was added and refluxed for 6 hours. 189 parts of 4-vinylcyclohexanol was obtained after stationary liquid separation.
After adding 200 parts of toluene and adding 100 parts of sodium metal, the temperature was raised to 60 ° C., and 345 parts (1.5 mole parts) of 2,2,2-dimethyl-1,3-dibromopropane was added over 2 hours. It was dripped. 100 parts of water was added to remove the remaining salt. After washing twice with water, the separated organic phase was heated to 150 ° C., distilled and purified at 130 Pa, and 2,2-dimethyl-1,3-propylene glycol bis (4-vinyl-1 (2) -cyclohexyl) 384 parts of ether (C-1) was obtained.

[Production Example 2] <Production of raw material unsaturated compound (C-2)>
1,4-butyleneglycol--in the same manner as in Production Example 1, except that 1,4-dibromobutane was changed to 324 parts (1.5 mole parts) instead of 2,2-dimethyl-1,3-dibromopropane 367 parts of bis (4-vinyl-1 (2) -cyclohexyl) ether (C-2) were obtained.

[Production Example 3] <Production of raw material unsaturated compound (C-3)>
Di (2-methyl-3-bromopropyl) ether was replaced with 390 parts (1.5 mole parts) instead of 2,2-dimethyl-1,3-dibromopropane in the same manner as in Production Example 1 350 parts of propylene glycol-bis (4-vinyl-1 (2) -cyclohexyl) ether (C-3) was obtained.

[Production Example 4] <Production of raw material unsaturated compound (D-1)>
In a reaction vessel equipped with a stirrer, a temperature controller and a condenser, 540 parts (5 mole parts) of “VCH” (4-vinylcyclohexene; manufactured by San Petrochemical Co., Ltd.) and 920 parts of 47.5% hydrobromic acid (5 parts) .4 mole parts) was added and heated to 100 ° C. After aging for 4 hours, after adding 200 parts of water, the mixture was allowed to stand for 1 hour and then separated to remove excess hydrobromic acid.
Further, the pressure was reduced to 130 ° C. at 40 ° C. to remove unreacted VCH, and 774 parts (4.1 mol parts) of 4-vinyl-1 (2) -bromocyclohexyl was obtained.
Thereto, 200 parts of diethyl ether and 102 parts (4.2 mole parts) of magnesium powder were added and heated to 40 ° C. and reacted for 6 hours. 267 parts (1.5 mole parts) of 2-ethyl-1,6-dichlorohexane was added dropwise over 3 hours. 200 parts of toluene was added to extract the product into a toluene phase, and after standing, the toluene phase was separated. The separated toluene phase is heated to 150 ° C. and purified by distillation at 130 Pa, and the target compound 2-ethylene-1,6-hexylene-bis (4-vinyl-1 (2) -cyclohexyl) (D-1) is obtained. 389 parts were obtained.

<Manufacture of epoxy resin>
[Example 1]
According to the production method (1) among the production methods (1) to (3) exemplified as the production method of the epoxy resin of the present invention, an epoxy resin (A-1) was produced by the following method.
A reaction vessel equipped with a stirrer, a temperature controller, and a reflux condenser was charged with the types and amounts (parts by weight) of the tungsten compound, 30% hydrogen peroxide solution and ammonium phosphate in this order in Table 1, 300 rpm The temperature was adjusted to 80 ° C. with stirring.
The mixed solution of the type and amount (parts by weight) of the solvent described in Table 1, the unsaturated compound (C-1) obtained in Production Example 1 and the phase transfer catalyst was subjected to the above temperature control solution at 80 ° C. over 2 hours. And dripped.
After completion of dropping, the reaction was allowed to proceed for 4 hours while maintaining the temperature at 80 ° C. After cooling to room temperature and allowing to stand, the upper layer (organic phase) containing the product was separated from the reaction mixture separated into two phases.
The obtained organic phase was washed twice with water, and about 10% by weight of 30% aqueous sodium hydroxide solution was added to the organic phase and stirred for about 30 minutes. After standing, the upper layer (organic phase) was taken out. The obtained organic phase was passed through a filter laid with alumina, and then the solvent was removed at 100 ° C. and 260 Pa to obtain colorless and transparent products.
As a result of elemental analysis of the product obtained in Example 1, it was C71.6%, H10.2%, O18.2%, and epoxy equivalent was 176 g / eq. From these results, it was confirmed that the product obtained in Example 1 was the target epoxy resin (A-1).

<Elemental analysis>
For elemental analysis, a fully automatic elemental analyzer manufactured by PerkinElmer was used. Carbon (C) and hydrogen (H) were quantified by chromatography after completely burning the sample in pure oxygen at 1800 ° C. Oxygen (O) was measured by converting oxygen generated by thermal decomposition into carbon monoxide using a carbon catalyst.
<Method for measuring epoxy equivalent>
The epoxy equivalent was measured according to JIS K-7236.

[Example 2]
The unsaturated compound (C-2) obtained in Production Example 2 was produced in the same manner as in Example 1 except that the type and amount of the tungsten compound, the hydrogen peroxide solution, and the solvent were changed. I got a thing.
As a result of analyzing the obtained product similarly, it was C71.0%, H10.0%, O18.9%, and epoxy equivalent was 169 g / eq. From these results, it was confirmed that the product obtained in Example 2 was the target epoxy resin (A-2).

[Example 3]
Similarly, the epoxy resin (A-3) was manufactured by the following method according to the manufacturing method (2) illustrated as a manufacturing method of an epoxy resin.
Perbenzoic acid was charged into the solvent of the type and amount shown in Table 1, and the unsaturated compound (C-3) obtained in Production Example 3 was added dropwise over 3 hours. The reaction was completed after aging at 50 ° C. for 6 hours. After removing the precipitated benzoic acid, 398 parts of sodium carbonate was further added at 15 ° C., and after neutralization, a 10% aqueous sodium hydroxide solution was added and stirred for about 30 minutes.
After standing, the upper layer (organic phase) was taken out. The obtained organic phase was washed with 1000 parts of deionized water, the crude liquid after washing was depressurized at 60 ° C. and 130 Pa, the low boiling point was removed, and the distillation residue was further subjected to column distillation at 90 ° C. and 40 Pa. It was.
To 250 parts of the obtained fraction, 20 parts of sodium thiosulfate as a reducing agent was added and stirred at 40 ° C. for 1 hour for reduction treatment. Further, 10 parts of activated carbon was added and stirred at 60 ° C. for 1 hour. , And filtered through filter paper laid with Celite 545 (manufactured by Showa Chemical Co., Ltd.). The reduction of the oxidant-activated carbon adsorption-filtration was repeated 5 times to obtain a colorless and transparent product.
As a result of analyzing the obtained product similarly, it was C69.1%, H9.9%, O20.9%, and epoxy equivalent was 191 g / eq. From these results, it was confirmed that the product obtained in Example 3 was the target epoxy resin (A-3).

[Example 4]
The unsaturated compound (D-1) obtained in Production Example 4 was produced in the same manner as in Example 3 to obtain a colorless and transparent product.
As a result of analyzing the obtained product similarly, they were C80.8%, H10.9%, O8.3%, and epoxy equivalent was 193 g / eq. From these results, it was confirmed that the product obtained in Example 4 was the target epoxy resin (B-1).

The epoxy resins used in Comparative Examples 1 to 4 are as follows.
[Comparative Example 1]
“Rikaresin HBE-100”:
Hydrogenated bisphenol A type epoxy resin (Dainippon Ink Co., Ltd .: epoxy equivalent 204 g / eq)

[Comparative Example 2]
“Celoxide 2021”:
3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate; alicyclic epoxy resin (manufactured by Daicel Chemical Industries, Ltd .: epoxy equivalent 130 g / eq)

[Comparative Example 3]
“Celoxide 2081”:
Adduct of 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate and ε-caprolactone; flexible alicyclic epoxy resin (manufactured by Daicel Chemical Industries, Ltd .: epoxy equivalent 200 g / eq)

[Comparative Example 4]
A mixture of “HBE-100” and Celoxide 2021P at a weight ratio of 80:20

  Table 2 shows the analysis results of the epoxy resins of Examples 1 to 4 and Comparative Examples 1 to 4, and the reactivity (curability with various curing agents and homopolymerization with a curing catalyst).

In addition, the measurement of the physical property in an Example and a comparative example was performed with the following method.
<Measurement method of total chlorine content>
The total chlorine content was measured according to JIS K7243-3.

<Measurement method of viscosity>
According to JISK7117-2, the epoxy resin was kept at 25 ° C., and then the viscosity was measured using a B-type rotational viscometer.

<Reactivity evaluation method>
The reactivity was evaluated by the surface tack after heat drying by changing the kind of curing agent or curing catalyst and curing conditions.
The following three types of acid anhydride curing agent, amine curing agent, and phenol curing agent were blended with an equivalent amount of epoxy resin, respectively, and a total of 10 g was weighed, and “2E4MZ-CN” (imidazole series) was used as a curing accelerator therein. 1 g of a catalyst (manufactured by Shikoku Kasei Co., Ltd.) was added, mixed, put into a silicon cup having a diameter of 3 cm, and left in a dryer under the following conditions.
As the curing catalyst, 10 g of an acid generator blended with 3 parts by weight of the epoxy resin was weighed, mixed, and then cured in the same manner as when the curing agent was used.
The results are shown in Table 2 when the surface was not tacky due to finger erosion, and when the surface was partially tacked, the result was x.

(1) Acid anhydride curing agent “Licacid MH” (methylhexahydrophthalic anhydride, manufactured by Shin Nippon Rika Co., Ltd .: acid anhydride equivalent 168 g / eq), 120 ° C. × 3 hours, 150 ° C. × 3 hours Cured with.
(2) Amine curing agent “Lalomin C260” (manufactured by BASF: active hydrogen equivalent 57 g / eq), 110 ° C. × 4 hours, 150 ° C. × 4 hours.
(3) Phenol curing agent “Resitop PSM-4324” (manufactured by Gunei Chemical Industry Co., Ltd .; hydroxyl group equivalent 105 g / eq), 160 ° C. × 1 hour.
(4) Acid generator “Sun-Aid SI-100” (manufactured by Sanshin Chemical Industry Co., Ltd.) is used for curing at 90 ° C. × 3 hours and 160 ° C. × 3 hours.

<Method for preparing cured product>
Examples 5-8 and Comparative Examples 5-8
It mix | blended with the mixing | blending component of Table 3, and the number of parts (weight part), it knead | mixed and defoamed using the defoamer in which centrifugal kneading is possible, and the epoxy resin composition was obtained.
The obtained epoxy resin composition was cast so that a test piece having a size required for the evaluation test described in Table 4 was obtained.
The sheet-shaped test piece having a uniform thickness was cast into a mold composed of two glass plates and a spacer sandwiched between them. 120 ° C. × 3 hours and further 160 ° C. × 5 hours were heat-cured to obtain a test piece made of a cured epoxy resin.

  The curing agents and curing accelerators in Table 3 are as follows.

<Curing agent>
Rikacid MH: Same as acid anhydride curing agent in Table 2 <Curing Accelerator>
U-CAT 18X: amine-based curing accelerator (manufactured by San Apro)

<Physical properties and performance of cured product>
Measurement of physical properties and performance evaluation of the cured product were performed by the following methods. Table 4 shows the physical properties and test results of the resulting cured product.

<Measuring method of glass transition point (Tg)>
As a method for measuring the glass transition temperature, a thermomechanical analyzer (TMA) was used.
As a measurement sample, a cured resin having a size of (length) 18 mm × (width) 2 mm × (thickness) 0.2 mm at 25 ° C. was used. The length and width of the cured product were measured with a vernier caliper, and the thickness was measured with a film thickness meter, each measuring up to an order of 0.001 mm.
Using a TMA / SS6000 manufactured by SII, a load of 10 mN was applied to the measurement sample, the inside of the measurement cell was held at 30 ° C. for 30 minutes, and then the measurement cell temperature was increased from 30 ° C. to 200 ° C. at 10 ° C./min. Warm up. A tangent line was drawn before and after the inflection point of the obtained TMA curve, and the intersection of the tangent lines was defined as Tg.

<Method for evaluating solder reflow resistance>
(1) A brass washer having an inner diameter of 3 mm, an outer diameter of 10 mm, and a thickness of 1 mm is put into a cylindrical mold made of silicone having a diameter of 30 mm.
(2) The epoxy resin compositions described in Examples and Comparative Examples are poured into the silicone mold so as to have a depth of 3 mm, and cured at 120 ° C. for 3 hours and 150 ° C. for 3 hours. After curing, the cured product was taken out from the silicone mold and used as a test piece with a washer.
(3) Ten test pieces are left in a high-temperature humidity chamber at 30 ° C. and 70% RH for 168 hours.
(4) The test piece was taken out from the high temperature and humidity chamber and placed in a solder reflow tester (UNI-6116G manufactured by Nippon Antom Co., Ltd.) that had been preheated to 100 ° C., and the temperature was raised to 230 ° C. at 50 ° C./min. Heat at ° C for 1 minute.
(5) Repeat the above heat cycle twice.
(6) Evaluation was made based on the number of samples in which 10 samples were peeled or cracked.
In all 10 samples, no peeling or cracking occurred, and in 1 out of 10 samples, peeling or cracking was marked as x.

<Method for evaluating heat resistance>
The total light transmittance (%) was measured according to JIS K7361 (1997) using a test piece of 20 mm × 40 mm × 1 mm.
The test piece was placed on a stainless steel vat and allowed to stand in a dryer at 120 ° C. for 100 hours, then removed from the dryer and radiated to room temperature.
The heat resistance was evaluated by comparing the transmittance retention after heating with the initial total light transmittance.
Calculate with the following formula.
Transmittance retention ratio (%) = total light transmittance after heating × 100 / initial total light transmittance (%)

<Light resistance evaluation method>
The light resistance before and after putting a test piece of 20 mm × 40 mm × 1 mm into an accelerated light resistance tester made by Iwasaki using an ultraviolet fluorescent lamp having a peak wavelength of 340 nm as a light source was evaluated.
First, after measuring the total light transmittance (%) before accelerated irradiation in accordance with JIS K7361 (1997), the epoxy resin test piece is irradiated with ultraviolet rays at 55 ° C. for 300 hours for an accelerated test. After irradiation, the total light transmittance was measured.
Light resistance was evaluated by comparing the transmittance retention after UV irradiation with the initial total light transmittance.
Transmittance retention (%) = total light transmittance after UV irradiation × 100 / initial total light transmittance (%)

<Crack resistance evaluation method>
(1) A brass washer having an inner diameter of 3 mm, an outer diameter of 10 mm, and a thickness of 1 mm is placed in a cylindrical silicone mold having a diameter of 30 mm.
(2) The epoxy resin compositions described in Examples and Comparative Examples are poured into the silicone mold so as to have a depth of 3 mm, and cured at 120 ° C. for 3 hours and 150 ° C. for 3 hours. After curing, the cured product was taken out from the silicone mold and used as a test piece with a washer.
(3) Ten test pieces are put into a gas phase thermal shock tester WINTECH (manufactured by ETAC), cooled to −40 ° C. × 15 minutes, and then heated to 150 ° C. × 15 minutes.
(4) Repeat the above heat cycle 50 times.
(5) Evaluation was made based on the number of samples in which 10 samples were peeled or cracked.
In all 10 samples, no peeling or cracking occurred, and in 1 out of 10 samples, peeling or cracking was marked as x.

As shown in Table 2, the epoxy resins of the present invention of Examples 1 to 4 have a total chlorine content of 0 ppm as impurities. On the other hand, the epoxy resins of Comparative Examples 1 and 4 have a high total chlorine content.
In addition, among Examples 1-4, the epoxy resin of Example 1 and Example 2 has little coloring. Moreover, the epoxy resin of Examples 1-4 has a low number of colors and a viscosity compared with the epoxy resin of the comparative example 1. Further, Comparative Examples 2 and 3 have a problem that tack remains for amine curing agents and phenol curing agents, whereas the epoxy resins of Examples 1 to 4 can react in all typical curing agent systems. The curability is excellent in terms.
Furthermore, as can be seen from Table 4, the cured products of Examples 5 to 8 are excellent in all evaluation items. On the other hand, for example, Comparative Example 5 is inferior in glass transition point, heat resistance, light resistance and crack resistance, Comparative Example 6 is inferior in solder reflow resistance and crack resistance, and Comparative Example 7 is in heat resistance and solder reflow resistance. The comparative example 8 is inferior in the glass transition point, heat resistance, light resistance, crack resistance and the like.

  The epoxy resin of the present invention is an epoxy resin having low viscosity, little coloration and excellent reactivity, and has excellent heat resistance, light transmission, light resistance, and crack resistance. It is useful as an agent, clear paint, optical component adhesive, semiconductor sealant, underfill agent, electronic, electrical component adhesive, liquid crystal sealant, optical fiber, coating agent, and resin raw materials for optical modeling.

Claims (7)

An epoxy resin (A) represented by the following general formula (1).
Wherein ^{(1), R} 1 OR 1 is an oxyalkylene group is a straight-chain or alkylene group branched having 1 to 20 carbon atoms; represents an n is an integer of 0 or 1 to 10. ] An epoxy resin (B) represented by the following general formula (2).
[In formula (2), ^{R 2} represents a linear or branched alkylene group having 1 to 20 carbon atoms. ] The epoxy resin of Claim 1 obtained by oxidizing the unsaturated compound (C) represented by following General formula (3) with hydrogen peroxide.
[In Formula (3), OR ¹ represents an oxyalkylene group having 1 to 20 carbon atoms, and n represents an integer of 0 to 10. ] The epoxy resin according to claim 2, obtained by oxidizing the unsaturated compound (D) represented by the following general formula (4) with hydrogen peroxide.
Wherein (4), ^{R 2} represents an alkylene group having 1 to 20 carbon atoms. ]   An epoxy resin composition comprising the epoxy resin according to claim 1 and a curing agent (H1) and / or a curing catalyst (H2).   A cured epoxy resin obtained by curing the epoxy resin composition according to claim 5.   The cured epoxy resin product according to claim 6, wherein the total light transmittance is 80% or more.