JP5051150B2 - Method for producing crystalline epoxy resin - Google Patents

Description

  The present invention is a novel material that is solid at room temperature, has excellent handleability, has a very low melt viscosity in the molten state, has excellent curability, and provides a cured product having excellent mechanical strength, heat resistance, and moisture resistance. The present invention relates to an epoxy resin and a method for producing the same, and is further useful for applications such as sealing materials, molding materials, casting materials, laminated materials, composite materials, adhesives and powder coatings for electrical and electronic parts. The present invention relates to a curable epoxy resin composition containing a crystalline epoxy resin and a cured product thereof.

Epoxy compounds are cured with various curing agents to give cured products with excellent mechanical properties, moisture resistance, electrical properties, etc., so sealing materials for electrical and electronic parts, molding materials, casting materials, laminate materials It is used in a wide range of fields such as composite materials, adhesives and powder coatings. However, with the advancement of technology, there is an increasing demand for higher performance of epoxy compounds, and conventional epoxy compounds can no longer meet the demands. For example, in the field of electrical and electronic applications, low-viscosity epoxy resins are desired as electronic parts become smaller and thinner, and this is sufficient for narrow gaps inside smaller parts. This is because it is necessary to feed resin. As low-viscosity epoxy resins, diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, etc. are widely used, but these epoxy resins are liquid or viscous at room temperature and are difficult to handle depending on the application. Yes, work is inferior. Further, cured bodies using these epoxy resins are not sufficient in mechanical strength, heat resistance and moisture resistance.
In order to solve these problems, a technique using an epoxy resin having crystallinity at room temperature or higher has been proposed. For example, tetramethylbiphenyl type epoxy resin (Patent Document 1), stilbene type epoxy resin (Patent Document 2), and the like. However, these epoxy resins have a bulky substituent in the vicinity of the epoxy group and thus have a high melt viscosity and are not sufficient in terms of curability. Moreover, although the hardened | cured body using these epoxy resins improves somewhat compared with the hardened | cured material using the above-mentioned bisphenol A type epoxy resin about heat resistance and moisture resistance, it is inadequate depending on a use.

Japanese Patent Publication No. 7-53791 Japanese Patent Laid-Open No. 9-12474

The present invention is a novel material that is solid at room temperature, has excellent handleability, has a very low melt viscosity in the molten state, has excellent curability, and provides a cured product having excellent mechanical strength, heat resistance, and moisture resistance. The present invention relates to an epoxy resin and a method for producing the same, and is further useful for applications such as sealing materials, molding materials, casting materials, laminated materials, composite materials, adhesives and powder coatings for electrical and electronic parts. An object of the present invention is to provide a curable epoxy resin composition containing an epoxy resin as a main component and a cured product thereof.

As a result of intensive studies to solve the above-mentioned problems, the present inventors can maintain a solid state because an epoxy resin having a specific chemical structure is crystalline at room temperature, and has a very low viscosity above the melting point. And the curable epoxy resin composition using the novel crystalline epoxy resin is found to be excellent in curability and give a cured product excellent in mechanical strength, heat resistance and moisture resistance, and to complete the present invention. It came.
That is, this invention relates to the invention selected from invention of the manufacturing method of the crystalline epoxy resin represented by the following general formula (I) among each following invention.

（Ｉ）
（式中、Ｒ^１〜Ｒ^１０は水素原子又は炭素数１〜６までのアルキル基を示す。ｎは０以上の整数を示す。）
で表される結晶性エポキシ樹脂。
（２）前記一般式（Ｉ）において、式中のＲ^１〜Ｒ^１０の全てが水素原子であるか、又はＲ^３、Ｒ^４がメチル基でその他が水素原子である、（１）項に記載された結晶性エポキシ樹脂。 (1) General formula (I)

(I)
^(Wherein, R 1 ^{to R 10} is .n represents an alkyl group of up to 1-6 hydrogen or C represents an integer of 0 or more.)
A crystalline epoxy resin represented by
(2) In the general formula (I), all of R ^{1 to} R ¹⁰ in the formula are hydrogen atoms, or R ³ and R ⁴ are methyl groups and the others are hydrogen atoms, The described crystalline epoxy resin.

（ＩＩ）
（式中、Ａはカリウム原子又はナトリウム原子を示し、Ｒ^１〜Ｒ^１０は水素原子又は炭素数１から６までのアルキル基を示す。）
で表されるジヒドロアントラハイドロキノン化合物のアルカリ金属塩をエピハロヒドリンと反応させることを特徴とする、（１）項に記載された一般式（Ｉ）で表される結晶性エポキシ樹脂の製造方法。 (3) General formula (II)

(II)
(In the formula, A represents a potassium atom or a sodium atom, and R ^{1 to} R ¹⁰ represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)
A method for producing a crystalline epoxy resin represented by general formula (I) described in item (1), wherein an alkali metal salt of a dihydroanthrahydroquinone compound represented by formula (1) is reacted with epihalohydrin.

(4) An alkali of a dihydroanthrahydroquinone compound in which R ^{1 to} R ¹⁰ in the formula are all hydrogen atoms, or R ³ and R ⁴ are methyl groups and the others are hydrogen atoms in the general formula (II) The method for producing a crystalline epoxy resin according to item (3), wherein the metal salt is reacted with epihalohydrin.

(5) In producing an epoxy compound by reacting an alkali metal salt of a dihydroanthrahydroquinone compound represented by the general formula (II) with an epihalohydrin, the alkali metal salt of the dihydroanthrahydroquinone compound is used as an aqueous solution in the reaction system. A method for producing a crystalline epoxy resin described in (3) or (4).

(6) The method for producing a crystalline epoxy resin according to (5), wherein the aqueous alkali metal salt solution of the dihydroanthrahydroquinone compound to be reacted with epihalohydrin is an aqueous solution having a concentration of 5 to 50% by mass.

(7) To 1 mol of dihydroanthrahydroquinone compound, 4 to 40 mol of epihalohydrin is used to obtain a uniform solution, and 1.8 to 5 mol of alkali metal hydroxide is added to 1 mol of dihydroanthrahydroquinone compound. The method for producing an epoxy compound according to any one of items (3) to (6), which is reacted.

（ＩＩＩ）
（式中、Ｒ^１〜Ｒ^１０は水素原子又は炭素数１〜６までのアルキル基を示す。）
で表されるジヒドロアントラハイドロキノン化合物をエピハロヒドリンと反応させることを特徴とする、（１）項に記載された前記一般式（Ｉ）で表される結晶性エポキシ樹脂の製造方法。
（９）前記一般式（ＩＩＩ）において、式中のＲ^１〜Ｒ^１０の全てが水素原子であるか、又はＲ^３、Ｒ^４がメチル基で、その他が水素原子であるジヒドロアントラハイドロキノン化合物をエピハロヒドリンと反応させることを特徴とする、（８）項に記載の結晶性エポキシ樹脂の製造方法。 (8) General formula (III)

(III)
^(Wherein, R 1 ^{to R 10} represents an alkyl group of up to 1-6 hydrogen atoms or carbon.)
A method for producing a crystalline epoxy resin represented by the general formula (I) described in the item (1), wherein the dihydroanthrahydroquinone compound represented by the formula (1) is reacted with epihalohydrin.
(9) A dihydroanthrahydroquinone compound in which, in the general formula (III), all of R ^{1 to} R ¹⁰ in the formula are hydrogen atoms, or R ³ and R ⁴ are methyl groups, and the others are hydrogen atoms. The method for producing a crystalline epoxy resin according to item (8), characterized by reacting with epihalohydrin.

(10) A curable epoxy resin composition comprising (a) an epoxy resin having two or more epoxy groups in the molecule, (b) a curing agent, and (c) a curing accelerator; A curable epoxy resin composition containing 5 to 100% by mass of the crystalline epoxy resin described in the item (1) or (2) in the epoxy resin.
(11) A cured product obtained by curing the curable epoxy resin composition described in item 10.

  The epoxy resin of the present invention is crystalline and is excellent in handleability because it is solid at room temperature, and has an extremely low melt viscosity in a melted state. In addition, the curable epoxy resin composition using the epoxy resin is excellent in curability and gives a cured product excellent in mechanical strength, heat resistance and moisture resistance. It is useful for applications such as casting materials, laminated materials, composite materials, adhesives and powder coatings.

2 is a chart showing an H-NMR spectrum of the epoxy resin obtained in Reference Example 1. FIG. 6 is a chart showing an IR spectrum of the epoxy resin obtained in Reference Example 1.

  The epoxy resin of the present invention represented by the general formula (I) can be obtained by reacting the dihydroanthrahydroquinone compound represented by the general formula (III) with an epihalohydrin in the presence of an alkali metal hydroxide. . For example, it is dissolved in an amount of epihalohydrin corresponding to 4 to 40 moles per mole of dihydroanthrahydroquinone compound under an inert gas stream to obtain a uniform solution. Next, while stirring the solution, an alkali metal hydroxide in an amount of 1.8 to 5 mol per mol of the dihydroanthrahydroquinone compound is added as a solid or an aqueous solution to react. This reaction can be carried out under normal pressure or reduced pressure, and the reaction temperature is usually 30 to 120 ° C. in the case of reaction under normal pressure and 30 to 80 ° C. in the case of reaction under reduced pressure. In the reaction, the reaction liquid is azeotroped while maintaining a predetermined temperature as necessary, the condensed liquid obtained by cooling the vaporized vapor is separated into oil / water, and the oil component excluding moisture is returned to the reaction system. It can be dehydrated by the method. Addition of the alkali metal hydroxide is intermittently or continuously added little by little over 1 to 8 hours in order to suppress a rapid reaction. The total reaction time is usually 1 to 10 hours. In addition, it is desirable that the inside of the system is an inert gas atmosphere until the reaction is completed. The inert gas here refers to, for example, nitrogen, argon or the like.

In the production of the novel epoxy resin of the present invention, in order to achieve both crystallinity and low viscosity, which are the features of the present invention, the molar ratio of epihalohydrin to dihydroanthrahydroquinone compound can be controlled, for example. The molar ratio of epihalohydrin to 1 mol of dihydroanthrahydroquinone compound is preferably 4 to 40 mol, more preferably 8 to 20 mol. If this molar ratio is lower than 4, the melt viscosity of the epoxy compound increases, and if it is higher than 40, the viscosity of the epoxy compound does not decrease any more, and it takes time to distill off the unreacted epihalohydrin, which is inefficient. .
After completion of the reaction, the insoluble by-product salt is removed by filtration or removed by washing with water, and then the unreacted epihalohydrin is removed by distillation under reduced pressure to obtain the desired epoxy resin.
As epihalohydrin in this reaction, epichlorohydrin or epibromohydrin is usually used. As the alkali metal hydroxide, sodium hydroxide or potassium hydroxide is usually used.

In this reaction, quaternary ammonium salts such as tetramethylammonium chloride and tetraethylammonium bromide; tertiary amines such as benzyldimethylamine and 2,4,6-tris (dimethylaminomethyl) phenol; 2-ethyl Catalysts such as imidazoles such as -4-methylimidazole and 2-phenylimidazole; phosphonium salts such as ethyltriphenylphosphonium iodide; phosphines such as triphenylphosphine may be used.
Furthermore, in this reaction, alcohols such as ethanol and 2-propanol; ketones such as acetone and methyl ethyl ketone; ethers such as dioxane and ethylene glycol dimethyl ether; glycol ethers such as methoxypropanol; dimethyl sulfoxide, dimethylformamide and the like Inert organic solvents such as aprotic polar solvents may be used alone or in combination of two or more.
Furthermore, when the amount of saponifiable halogen in the epoxy resin obtained as described above is too large, a purified epoxy resin having a sufficiently reduced amount of saponifiable halogen can be obtained by reprocessing. That is, the crude epoxy resin is redissolved in an inert organic solvent such as 2-propanol, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, dioxane, methoxypropanol, dimethyl sulfoxide, and the alkali metal hydroxide is dissolved in a solid or aqueous solution. In addition, after re-ringing reaction at a temperature of about 30 to 120 ° C. for 0.5 to 8 hours, excess alkali metal hydroxide or by-product salt is removed by a method such as washing with water, and the organic solvent is distilled under reduced pressure. When removed, a purified epoxy compound is obtained.

Moreover, the epoxy resin of this invention can also be manufactured by making the alkali metal salt of the dihydroanthrahydroquinone compound prepared beforehand react with epihalohydrin. In this case, the alkali metal salt of the dihydroanthrahydroquinone compound is added to the epihalohydrin as it is or in an aqueous solution, but in order to prevent a rapid reaction, it is desirable to add it into the system in small portions.
In addition, when supplied as an aqueous solution, in order to sufficiently advance the cyclization reaction, after removing water in the system on the way, an alkali metal hydroxide may be added in solid or aqueous solution to increase the epoxidation rate. desirable.
Moreover, the density | concentration of the alkali metal salt aqueous solution of the dihydroanthrahydroquinone compound is 5-50 mass%, Preferably it is 15-30 mass%. When the concentration is lower than 5% by mass, the amount of water brought into the system increases, which may inhibit the progress of the epoxidation reaction. If it is more than 50% by mass, the fluidity of the aqueous solution is lowered, and there is a possibility that the piping of the apparatus may be clogged.
Moreover, the alkali metal salt aqueous solution of a dihydroanthrahydroquinone compound can contain an alkali metal hydroxide in an equivalent amount or more necessary for forming a salt for stabilization. In addition, other organic solvents such as alcohols may be added to the aqueous solution as long as the stability is not impaired.
Even when an alkali metal salt of a dihydroanthrahydroquinone compound or an aqueous solution thereof is used as a starting material, an epoxy compound is obtained using various conditions, various reaction catalysts, various organic solvents and operations similar to the epoxidation reaction of the dihydroanthrahydroquinone compound. be able to. The above-described method can also be used when a crude epoxy resin is used as a purified epoxy resin.

Usually, the reaction solvent is distilled off at a temperature near or higher than the melting point of the epoxy compound, so that the epoxy resin immediately after the solvent is distilled off is in a molten state. A method for crystallizing the molten epoxy resin to form a solid is not particularly specified, and a known method can be used. For example, a method of extracting a molten epoxy resin at a high temperature into a vat or the like, and solidifying the crystal by natural cooling, and a method of adding a small amount of the crystalline solid of the epoxy resin prepared in advance as a crystal nucleus to promote crystallization , A method of promoting crystallization by stirring molten epoxy resin or applying vibration, a method of extracting while applying a strong external force with a kneader, etc., promoting crystallization while controlling the temperature so as not to overcool The method etc. are raised, These methods can be performed individually or in combination of two or more. It is desirable from the viewpoint of productivity that the novel epoxy resin of the present invention is also operated as described above to promote crystallization.
In order to further lower the viscosity and increase the purity of the epoxy resin, the crude epoxy resin or purified epoxy resin obtained by the reaction may be recrystallized using an appropriate solvent.

Dihydro anthrahydroquinone compounds used in the above reaction, in the formula (II), the substituents R ¹ to R ¹⁰ is an alkyl group of up to 1-6 hydrogen atoms or carbon. Among them, R ^{1 to} R ¹⁰ are preferably hydrogen atoms or methyl groups, and particularly preferably, all of R ^{1 to} R ¹⁰ are hydrogen atoms (1,4 dihydroanthrahydroquinone). The epoxy resin obtained from this is crystalline having a temperature of 80 to 120 ° C., and melts rapidly at a temperature equal to or higher than the melting point and has an extremely low viscosity.
Further, when an alkali metal salt of a dihydroanthrahydroquinone compound is used for the reaction, in the same manner as described above, the substituents R ^{1 to} R ¹⁰ in the general formula (III) are hydrogen atoms or alkyl groups having 1 to 6 carbon atoms, Among these, R ^{1 to} R ¹⁰ are preferably hydrogen atoms or methyl groups, and particularly preferably, all of R ^{1 to} R ¹⁰ are hydrogen atoms (alkali metal salt of 1,4-dihydroanthrahydroquinone).
Here, examples of the alkali metal that forms a salt include potassium and sodium. Generally, as a hydroxide (potassium hydroxide or sodium hydroxide), it is dissolved as it is or in a solvent such as water or alcohol. Supplied in form.

A known method can be used as a method for producing a dihydroanthrahydroquinone compound, which is a raw material for the novel epoxy resin of the present invention. For example, 1,4,4a, 9a-tetrahydroanthraquinone obtained by Diels-Alder reaction between 1,4-naphthoquinone and butadiene is used as an aromatic hydrocarbon such as benzene or xylene as a solvent, and paratoluenesulfonic acid as a catalyst. And a method of obtaining crystals by cooling after isomerization reaction at 80 to 100 ° C. for 30 minutes to 3 hours (Japanese Patent Laid-Open No. 54-122263).
Similarly, a known method can be used as a method for producing an alkali metal salt of a dihydroanthrahydroquinone compound. For example, a method obtained by dissolving the dihydroanthrahydroquinone compound obtained by the above method in an aqueous solution in which at least an equivalent amount (2 times mole of the dihydroanthrahydroquinone compound) of an alkali metal hydroxide is dissolved, and 1,4-naphthoquinone An aqueous solution in which at least an equivalent amount (1,4,4a, 9a-tetrahydroanthraquinone) of 1,4,4a, 9a-tetrahydroanthraquinone obtained by Diels-Alder reaction with butadiene is dissolved; By contacting, 1,4,4a, 9a-tetrahydroanthraquinone isomerizes and can be obtained as an aqueous solution of an alkali metal salt of a dihydroanthrahydroquinone compound. In addition, an aqueous solution of disodium salt of 1,4-dihydroanthrahydroquinone in which R ^{1 to} R ¹⁰ are hydrogen atoms in the above general formula (III) has already been widely used in the world for applications such as pulp cooking aids. This can be used as it is.

  The curable epoxy resin composition of the present invention comprises (a) an epoxy resin having two or more epoxy groups in one molecule, (b) a curing agent, and (c) a curing accelerator as essential components. The epoxy resin is characterized by including the novel epoxy resin of the present invention. Moreover, in (a) epoxy resin, in addition to the novel epoxy resin of the present invention, an epoxy resin having two or more epoxy groups in one molecule can be used in combination, and a known epoxy resin is used as the epoxy resin. be able to. For example, bisphenol A type, bisphenol F type, biphenyl type, tetramethyl biphenyl type, cresol novolak type, phenol novolak type, bisphenol A novolak type, dicyclopentadiene phenol condensation type, phenol aralkyl condensation type, etc. Examples thereof include an epoxy resin and an aliphatic epoxy resin. These epoxy resins can be used alone or in combination of two or more, but the amount of the epoxy compound of the present invention is 5 to 100% by mass in the whole epoxy resin. When the blending amount is lower than 5% by mass, the effect of the present invention is not sufficiently exhibited.

(B) The curing agent is not particularly specified, and a known epoxy resin curing agent can be used. Examples of these epoxy resin curing agents include polyphenols such as bisphenol A, bisphenol F, bisphenol S, thiodiphenol, hydroquinone, resorcin, biphenol, tetramethylbiphenol, dihydroxynaphthalene, dihydroxydiphenyl ether, phenol novolac resins, Cresol novolak resin, bisphenol A novolak resin, naphthol novolak resin, phenol resin obtained by condensation reaction of various phenols with various aldehydes such as benzaldehyde, hydroxybenzaldehyde, crotonaldehyde, glyoxal, etc., phenol aralkyl resin, phenol modification Various phenols such as xylene resin, phenol terpene resin, dicyclopentadiene phenol resin Resin, active ester compounds obtained by esterification such as benzoate or acetate of all or part of phenolic hydroxyl groups of various phenols (resins), methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, pyromellitic anhydride Acids, acid anhydrides such as methyl nadic acid, and amines such as diethylenetriamine, isophoradiamine, diaminodiphenylmethane, diaminodiphenylsulfone, and dicyandiamide. The curing agent may be used alone or in combination of two or more. The amount of the curing agent used is such that (a) 1 mol of the epoxy group in all components of the epoxy resin is 0.5 to 2.0 mol of a group that reacts with the epoxy group in the entire curing agent. Is preferable, and more preferably 0.7 to 1.2 mol.

(C) There is no designation | designated as a hardening accelerator in particular, A well-known hardening accelerator can be used. Examples of the curing accelerator include phosphine compounds such as tributylphosphine, triphenylphosphine, tris (dimethoxyphenyl) phosphine, tris (hydroxypropyl) phosphine, tris (cyanoethyl) phosphine, tetraphenylphosphonium tetraphenylborate, methyltributylphosphonium. Phosphonium salts such as tetraphenylborate, methyltricyanoethylphosphonium tetraphenylborate, 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 1-cyanoethyl-2-methylimidazole, 2,4-dicyano-6- [2-methylimidazolyl- (1)]-ethyl-s-triazine, 2,4-dicyano-6- [2-unde Imidazoles such as loumidazolyl- (1)]-ethyl-s-triazine, 1-cyanoethyl-2-undecylimidazolium trimellitate, 2-methylimidazolium isocyanurate, 2-ethyl-4-methylimidazolium tetra Phenylborate, imidazolium salts such as 2-ethyl-1,4-dimethylimidazolium tetraphenylborate, 2,4,6-tris (dimethylaminomethyl) phenol, benzyldimethylamine, tetramethylbutylguanidine, N-methylpiperazine , Amines such as 2-dimethylamino-1-pyrroline, ammonium salts such as triethylammonium tetraphenylborate, 11,5-diazabicyclo [5,4,0] -7-undecene, 1,5-diazabicyclo [4,3 , 0] -5 Nene, 1,4-diazabicyclo [2,2,2] - diazabicyclo compounds such as octane, tetraphenylborate thereof diazabicyclo compounds, phenol salts, phenol novolak salts and 2-ethyl hexanoate and the like. Among these compounds serving as curing accelerators, phosphine compounds, imidazole compounds, diazabicyclo compounds, and salts thereof are preferable. These curing accelerators are used alone or in combination of two or more, and the amount used is 0.1 to 7% by mass relative to the total epoxy compound.

In addition, the epoxy compound curable resin composition of the present invention appropriately includes a filler, a coupling agent, a flame retardant, a flame retardant aid, a plasticizer, a solvent, a reactive diluent, a pigment, and the like. Can be blended.
The curable epoxy resin composition of the present invention may be prepared by using a method similar to a conventionally known method, as long as all compounding components such as an epoxy resin, a curing agent, and a curing accelerator are uniformly mixed. It can be a thing. Examples of the method include melt kneading using a kneader, roll or extruder, and dry blending in which powdery components are mixed. The composition thus obtained may be pulverized or classified as necessary.
Also, the curable epoxy resin composition of the present invention can be dissolved in a solvent such as acetone, methyl ethyl ketone, methyl cellosolve, dimethylformamide, toluene, xylene, etc. to obtain a varnish-like composition. A cured product can be obtained by hot press-molding a prepreg obtained by impregnating a base material such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, paper, and the like, followed by heating and drying.
The cured product of the present invention can be obtained by thermally curing the curable epoxy resin composition of the present invention, and is in the form of a molded product, a laminate, a cast product, an adhesive, a coating film, a film and the like. For example, when the form is a molded product, the cured product can be obtained by heating the composition at 30 to 250 ° C. for 30 seconds to 10 hours using a casting, transfer molding machine, injection molding machine, etc. In the case of varnish, a cured product can be obtained by hot press-molding a prepreg obtained by impregnating a base material such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, paper and the like, followed by heating and drying.

  As described above, the novel epoxy resin of the present invention is solid at room temperature, has excellent handleability, has an extremely low melt viscosity in the molten state, and has excellent curability, and is cured using this resin. Since the epoxy resin composition can provide a cured product having excellent mechanical strength, heat resistance and moisture resistance, it is a sealing material for electrical and electronic parts, a molding material, a casting material, a laminated material, a composite material, Useful in applications such as adhesives and powder coatings.

EXAMPLES Hereinafter, although an Example is raised and this invention is demonstrated in detail, this invention is not limited to these Examples, unless the summary is exceeded.
(Reference Example 1)
1050 g of epichlorohydrin and 410 g of 2-propanol were charged into a 3 L four-necked flask equipped with a stirrer, a reflux condenser and a thermometer, and the system was purged with nitrogen under reduced pressure. To this, 200 g of 1,4-dihydroanthrahydroquinone was added in a nitrogen atmosphere, and the mixture was heated to 40 ° C. and dissolved uniformly. Then, 180 g of a 48.5 mass% sodium hydroxide aqueous solution was added dropwise over 90 minutes. During this time, the temperature was gradually raised, and the temperature inside the system was adjusted to 65 ° C. after the dropping was completed.
Thereafter, the reaction was completed by maintaining at 65 ° C. for 30 minutes, and by-product salt and excess sodium hydroxide were removed by washing with water. Subsequently, excess epichlorohydrin and 2-propanol were distilled off from the product under reduced pressure to obtain a crude epoxy resin mixture.
This crude epoxy resin mixture was dissolved in 460 g of methyl isobutyl ketone, 7 g of a 48.5 mass% sodium hydroxide aqueous solution was added, and the mixture was reacted at a temperature of 65 ° C. for 1 hour. Thereafter, an aqueous sodium hydrogen phosphate solution was added to the reaction solution to neutralize excess sodium hydroxide, followed by washing with water to remove by-product salts. The temperature was controlled so that the liquid temperature was 65 to 90 ° C. during washing with water. Subsequently, after methyl isobutyl ketone was completely removed under heating and reduced pressure, the resinous material in a molten state was taken out into a vat, stirred for 10 times with a glass rod, and then naturally cooled at room temperature. About 2 hours later, the whole crystallized and was taken out to obtain 285 g of a yellow crystalline epoxy resin. The obtained epoxy resin had an epoxy equivalent of 176 g / eq, hydrolyzable chlorine of 450 ppm, a melt viscosity at 150 ° C. of 16 mPa · s, and a melting point of 104 ° C. by DSC measurement. It was solid at room temperature and the handleability was good. H-NMR spectrum of the obtained epoxy resin is shown in FIG. 1-1, and attribution of each peak shown in Formula (V) is shown in Table 1. The IR spectrum of the obtained epoxy resin is shown in FIG. From the above, it was confirmed that an epoxy resin represented by the following chemical formula (IV) and n = 0.1 (from GPC) was obtained.
FIG. 1 shows the H-NMR spectrum of the resin obtained in Reference Example 1.
FIG. 2 shows the IR spectrum of the epoxy resin obtained in Reference Example 1.

（ＩＶ）

(IV)

（Ｖ）

(V)

(Reference Example 2)
In Reference Example 1, 225 g of 1,4-dihydro-2,3-dimethylanthrahydroquinone is used in place of 200 g of 1,4-dihydroanthrahydroquinone, and the same operation as in Example 1 is performed, which is represented by the chemical formula (VI). An epoxy resin 306 g was obtained. The obtained epoxy resin had an epoxy equivalent of 194 g / eq, hydrolyzable chlorine of 435 ppm, a melt viscosity at 150 ° C. of 17 mPa · s, and a melting point of 94 ° C. by DSC measurement. From GPC, n = 0.1 in the chemical formula (VI). At room temperature, it was a yellow crystalline solid and handleability was good.

（ＶＩ）

(VI)

Example 1
Epichlorohydrin (1050 g) and 2-propanol (410 g) were charged into a 3 L four-necked flask equipped with a stirrer, a reflux condenser and a thermometer, and the system was purged with nitrogen under reduced pressure, and the temperature was maintained at 40 ° C. Under a nitrogen atmosphere, 900 g of a 28% by mass aqueous solution of 1,4-dihydroanthrahydroquinone sodium salt was added dropwise thereto over 90 minutes. During this period, the temperature was gradually raised, and the temperature was controlled so that the temperature inside the system was 65 ° C. after the completion of the dropping. Thereafter, after holding at 65 ° C. for 30 minutes, water containing secondary salts was discharged by liquid-liquid separation. Next, while maintaining the system at 65 ° C., 32 g of a 48.5 mass% sodium hydroxide aqueous solution was dropped over 15 minutes, and then the reaction was completed over 30 minutes. Thereafter, secondary salts were removed by washing with water, and excess epichlorohydrin and 2-propanol were distilled off from the product under reduced pressure to obtain a crude epoxy resin mixture.
This crude epoxy resin mixture was dissolved in 460 g of methyl isobutyl ketone, 7 g of a 48.5 mass% sodium hydroxide aqueous solution was added, and the mixture was reacted at a temperature of 65 ° C. for 1 hour. Thereafter, an aqueous sodium hydrogen phosphate solution was added to the reaction solution to neutralize excess sodium hydroxide, followed by washing with water to remove by-product salts. Subsequently, after methyl isobutyl ketone was completely removed under heating and reduced pressure, the resinous material in a molten state was taken out into a vat, stirred for 10 times with a glass rod, and then naturally cooled at room temperature. About 2 hours later, the whole crystallized and was taken out to obtain 290 g of a yellow crystalline epoxy compound. The epoxy compound thus obtained had an epoxy equivalent of 174 g / eq, hydrolyzable chlorine of 390 ppm, a melt viscosity at 150 ° C. of 15 mPa · s, a melting point by DSC measurement of 106 ° C., a solid at room temperature and good handleability. . The obtained epoxy resin has almost the same H-NMR and IR spectrum as the epoxy resin obtained in Reference Example 1, and is represented by the chemical formula (IV), and n = 0.08 (from GPC). It was confirmed that a resin was obtained.

(Examples 2 to 4)
The epoxy resins obtained in Reference Examples 1 and 2 and Example 1, a phenol novolak resin (softening point 84 ° C., hydroxyl group equivalent 103 g / eq) and a phenol aralkyl resin (softening point 83 ° C., hydroxyl group equivalent 175 g / eq) as a curing agent. ) Is melt-mixed at 120 ° C. in a glass beaker, and a composition obtained by adding and mixing a predetermined amount of triphenylphosphine as a curing accelerator is cast, 175 ° C., After curing for 7 hours, a cured product was obtained. Various physical properties of the obtained cured product are shown in Table 2.

(Comparative Examples 1 and 2)
In Example 2, instead of the epoxy resin obtained in Reference Example 1, bisphenol A type epoxy resin (liquid at normal temperature, viscosity at 150 ° C. is 10 mPa · s), tetramethyl biphenol type epoxy resin (melting point 105 ° C., 150 ° C. Table 2 shows the results of measuring the cured properties by obtaining a cured product in the same manner as in Example 4 using a viscosity of 15 mPa · s).
As described above, the epoxy compound of the present invention is a crystalline resin and is excellent in handleability because it is solid at room temperature, and has a very low viscosity in a molten state. Moreover, the result that the curable epoxy resin composition using the epoxy resin gave the hardened | cured material excellent in sclerosis | hardenability, mechanical strength, heat resistance, and moisture resistance was obtained.

（＊１）熱板法，１７５℃
（＊２）ＴＭＡを用いて測定した．
（＊３）ＪＩＳＫ６９１１に従ってテストを行った．
（＊４）８５℃、８５％ＲＨ７２ｈｒ後の吸湿率．

(* 1) Hot plate method, 175 ° C
(* 2) Measured using TMA.
(* 3) The test was conducted according to JISK6911.
(* 4) Moisture absorption after 85 ° C. and 85% RH 72 hr.

The epoxy compound of the present invention has crystallinity and is excellent in handleability because it is solid at room temperature, and has a low melt viscosity. A composition using this has excellent curability, mechanical strength, heat resistance, and moisture resistance. Since it provides a cured product having excellent properties, it is useful for sealing materials, molding materials, adhesives, paints, and the like.

Claims (4)

Formula (I)

(I)
^(Wherein, R 1 ^{to R 10} is .n represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms is an integer of 0 or more.)
A method for producing an epoxy resin represented by
Formula (II)

(II)
^(Wherein, R 1 ^{to R 10} is .A represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms represents a potassium atom or a sodium atom.)
A method for producing a crystalline epoxy resin, comprising reacting an alkali metal salt of a dihydroanthrahydroquinone compound represented by formula (II) with epihalohydrin. In the general formula (II) and general formula (I), all of R ^{1 to} R ¹⁰ are hydrogen atoms, or, among R ^{1 to} R ¹⁰ , R ³ and R ⁴ are methyl groups, and the others are hydrogen atoms. The method for producing a crystalline epoxy resin according to claim 1, wherein: The crystalline epoxy resin according to claim 1 or 2, wherein the alkali metal salt of the dihydroanthrahydroquinone compound represented by the general formula (II) is supplied to the reaction system as an aqueous solution and reacted with epihalohydrin. Manufacturing method. The method for producing a crystalline epoxy resin according to claim 3, wherein the aqueous solution of the alkali metal salt of the dihydroanthrahydroquinone compound is an aqueous solution having a concentration of 5 to 50% by weight.

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