JP3543282B2 - Method for producing epoxy resin, and cured product of epoxy resin composition - Google Patents

Description

【０００７】
（式中、ｍは０〜１０の整数を表し、Ｒは水素原子あるいは炭素数１〜４のアルキル基を表す。）
で表される化合物の水酸基１当量当り２．５〜１０モルのエピハロヒドリンを反応させて得られる下記式（２）
【０００８】
【化４】

【０００９】
（式中、ｎは正数を表す。ｍは０〜１０の整数を表し、Ｒは水素原子あるいは炭素数１〜４のアルキル基を表す。Ｇはグリシジル基を表す。）
【００１０】
で表されるエポキシ樹脂の製造方法、
（２）反応に際して４級アンモニウム塩を使用する上記（１）記載のエポキシ樹脂の製造方法、
（３）反応に際して非プロトン性極性溶媒を使用する上記（１）記載のエポキシ樹脂の製造方法、
（４）上記（１）、（２）または（３）記載の製造方法で得られたエポキシ樹脂を含有するエポキシ樹脂組成物の硬化物
を提供するものである。
【００１１】
以下、本発明の詳細を説明する。
本発明のエポキシ樹脂の製造方法としては、例えば前記式（１）で表される化合物を、特定量のエピハロヒドリンに溶解し、アルカリ金属水酸化物の存在下で反応させる方法が挙げられる。
【００１２】
式（１）、（２）中におけるＲはそれぞれ独立して存在し、水素原子以外の具体例としてはメチル基、エチル基、プロピル基、ブチル基などが挙げられ、これらは１分子中に、１個、或は複数個存在してもよい。本発明において用いうる式（１）の化合物の具体例としては、２−メチル−１，４−シクロヘキサンジメタノール、２，５−ジメチル−１，４−シクロヘキサンジメタノール、１，４−シクロヘキサンジメタノール等が挙げられるがこれらに限定されない。
【００１３】
本発明においては、式（１）で表される化合物とエピハロヒドリンを反応させる。用いうるエピハロヒドリンの具体例としては、エピクロルヒドリン、エピブロムヒドリン、エピヨードヒドリン等が挙げられるが、エピクロルヒドリンが特に好ましい。エピハロヒドリンの使用量は、通常、式（１）で表される化合物の水酸基１当量に対して、２．５〜１０倍モルであり、特に３〜８倍モルが好ましい。
【００１４】
本発明においては、好ましくは式（１）で表される化合物とエピハロヒドリンの溶解混合物にテトラメチルアンモニウムクロライド、テトラメチルアンモニウムブロマイド、トリメチルベンジルアンモニウムクロライドなどの第４級アンモニウム塩を触媒として添加し、アルカリ金属水酸化物の水溶液あるいは固体を加え反応させる。
【００１５】
このとき使用される４級アンモニウム塩の使用量としては、式（１）で表される化合物の水酸基１当量に対して、通常１〜１０グラムであり、２〜８グラムが好ましい。
【００１６】
本発明においては、式（１）で表される化合物とエピハロヒドリン及び４級アンモニウム塩の混合物に水酸化ナトリウム、水酸化カリウム等のアルカリ金属水酸化物を添加し、または添加しながら２０〜１００℃の温度で１〜２０時間反応させる。上記反応において、アルカリ金属水酸化物はその水溶液を使用してもよく、その場合は該アルカリ金属水酸化物の水溶液を連続的に反応混合物中に添加すると共に減圧下、または常圧下、連続的に水及びエピハロヒドリンを留出させ、更に分液し水は除去しエピハロヒドリンは反応混合物中に連続的に戻す方法でもよい。
【００１７】
この反応において使用されるアルカリ金属水酸化物の使用量は通常、式（１）で表される化合物の水酸基１当量に対し１〜２モル、好ましくは１．１〜１．８モルである。
【００１８】
また上記４級アンモニウム塩の代わりにジメチルスルホン、ジメチルスルホキシドなどの非プロトン性極性溶媒を添加して反応を行うこともできる。非プロトン性極性溶媒を添加する場合、その使用量はエピハロヒドリンの使用量に対して５〜１００重量％が好ましく、特に１０〜９０重量％が好ましい。
【００１９】
この反応の場合アルカリ金属水酸化物の使用量は通常、式（１）で表される化合物の水酸基１当量に対し０．８〜１．５モル、好ましくは０．９〜１．１モルである。
【００２０】
これらのエポキシ化反応においては、４級アンモニウム塩を使用した場合、通常水洗を行った後、未反応のエピハロヒドリンを除去する。また、非プロトン性極性溶媒を使用した場合、特に水洗の工程は必要でなくそのまま次のエピハロヒドリンの除去工程を行うことができる。
上記において、エピハロヒドリン（及び非プロトン性極性溶媒）は、公知の方法、例えば生成物を加熱減圧蒸留することにより除去することができる。エピハロヒドリン等を除去した後の残留物は、通常有機溶媒に溶解する。用いうる有機溶剤の具体例としては、メチルイソブチルケトン、ベンゼン、トルエン、キシレン等が挙げられるが、メチルイソブチルケトン、トルエンが好ましい。またこれらは単独もしくは混合して使用できる。
【００２１】
その後、原料として使用した式（１）で表される化合物の水酸基１当量に対して０．０１〜０．３倍当量のアルカリ金属水酸化物を加え、５０〜８０℃で３０分〜３時間撹拌し、脱ハロゲン化水素反応を行うことが好ましい。このアルカリ金属水酸化物は１０〜４０重量％水溶液として用いることが好ましい。
【００２２】
反応終了後、樹脂溶液を数回水洗した後、有機溶剤を加熱減圧下で留去することにより目的とする式（２）で表されるエポキシ樹脂を得ることが出来る。
【００２３】
本発明により得られるエポキシ樹脂は単独でまたは他のエポキシ樹脂との併用で通常のエポキシ樹脂の場合と同様に硬化剤、さらに必要により硬化促進剤等を添加したエポシ樹脂組成物を得て、これを加熱することにより硬化させ本発明の硬化物を得ることができる。併用する場合本発明により得られるエポキシ樹脂が全エポキシ樹脂中に占める割合は通常５重量％以上であり、好ましくは１０重量％以上である。この場合、用いられるエポキシ樹脂は通常は１分子中に２個以上のエポキシ基を有する化合物が挙げられる。併用し得るエポキシ樹脂の具体例としてはフェノールノボラック型エポキシ樹脂、クレゾールノボラック型エポキシ樹脂、ナフトールノボラック型エポキシ樹脂などのノボラック型エポキシ樹脂、トリフェニルメタン型エポキシ樹脂、ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂、ビスフェノールＡＤ型エポキシ樹脂、ビスフェノールＳ型エポキシ樹脂、ビスフェノールＩ型エポキシ樹脂、ビフェニル型エポキシ樹脂、ジヒドロキシベンゼン型エポキシ樹脂などの芳香族２価フェノール類から得られるエポキシ樹脂、フタル酸、ダイマー酸などの多塩基酸とエピハロヒドリンとの反応によるグリシジルエステル型エポキシ樹脂、またジアミノジフェニルメタン、イソシアヌール酸などのポリアミンとエピハロヒドリンの反応により得られるグリシジルアミン型エポキシ樹脂などが挙げられる。これらエポキシ樹脂は単独で用いてもよく、２種以上を混合してもよい。
【００２４】
本発明の硬化物を得る際に用いる硬化剤の例としてはアミン系化合物、酸無水物系化合物、アミド系化合物、フェノ−ル系化合物などが挙げられる。それらの具体例としては、ジアミノジフェニルメタン、ジエチレントリアミン、トリエチレンテトラミン、ジアミノジフェニルスルホン、イソホロンジアミン、ジシアンジアミド、リノレン酸の２量体とエチレンジアミンとより合成されるポリアミド樹脂、無水フタル酸、無水トリメリット酸、無水ピロメリット酸、無水マレイン酸、テトラヒドロ無水フタル酸、メチルテトラヒドロ無水フタル酸、無水メチルナジック酸、ヘキサヒドロ無水フタル酸、メチルヘキサヒドロ無水フタル酸、フェノ−ルノボラック、及びこれらの変性物、イミダゾ−ル、ＢＦ_３ −アミン錯体、グアニジン誘導体などが挙げられる。これらの硬化剤はそれぞれ単独で用いてもよいし、２種以上組み合わせて用いてもよい。
【００２５】
これらの硬化剤の使用量は、エポキシ基に対して０．７〜１．２当量が好ましい。エポキシ基に対して、０．７当量に満たない場合、あるいは１．２当量を超える場合、いずれも硬化が不完全となり良好な硬化物性が得られない恐れがある。
【００２６】
また上記硬化剤を用いる際に硬化促進剤を併用しても差し支えない。用いうる硬化促進剤の具体例としては例えば２−メチルイミダゾール、２−エチルイミダゾール、２−エチル−４−メチルイミダゾール等のイミダゾ−ル類、２−（ジメチルアミノメチル）フェノール、１，８−ジアザ−ビシクロ（５，４，０）ウンデセン−７等の第３級アミン類、トリフェニルホスフィン等のホスフィン類、オクチル酸スズなどの金属化合物などが挙げられる。硬化促進剤はエポキシ樹脂１００重量部に対して０．１〜５．０重量部が必要に応じ用いられる。
【００２７】
本発明におけるエポキシ樹脂組成物は、必要に応じて無機充填材を含有する。用い得る無機充填材の具体例としてはシリカ、アルミナ、タルクなどが挙げられる。無機充填材はエポキシ樹脂組成物中において０〜９０重量％を占める量が用いられる。さらに、本発明におけるエポキシ樹脂組成物には、必要に応じてシランカップリング剤、ステアリン酸、パルミチン酸、ステアリン酸亜鉛、ステアリン酸カルシウム等の離型剤、顔料等種々の配合剤を添加することができる。
【００２８】
上記エポキシ樹脂組成物は上記各成分を所定の割合で均一に混合することによって得ることができる。上記のエポキシ樹脂組成物から従来知られている方法と同様の方法で容易にその硬化物を得ることができる。例えば本発明により得られるエポキシ樹脂と硬化剤、並びに必要により硬化促進剤、無機充填材及びその他の配合剤とを必要に応じて押出機、ニ−ダ、ロ−ル等を用いて均一になるまで充分に混合してエポキシ樹脂組成物を得、そのエポキシ樹脂組成物を溶融後注型あるいはトランスファ−成形機などを用いて成形し、さらに８０〜２００℃に加熱することにより本発明の硬化物を得ることができる。
【００２９】
また上記エポキシ樹脂組成物を溶剤に溶解させ、ガラス繊維、カ−ボン繊維、ポリエステル繊維、ポリアミド繊維、アルミナ繊維、紙などの基材に含浸させ加熱乾燥して得たプリプレグを熱プレス成形して硬化物を得ることもできる。
【００３０】
この際用いうる溶剤の具体例としてはメチルエチルケトン、アセトン、メチルイソブチルケトン等が挙げられ、その使用量は本発明のエポキシ樹脂組成物と該溶剤の混合物中で通常１０〜７０重量％、好ましくは１５〜６５重量％を占める量を用いる。
【００３１】
【実施例】
次に本発明を実施例により更に具体的に説明するが、以下において部は特に断わりのない限り重量部である。また、実施例中の全塩素濃度とは、試料のジオキサン溶液に１Ｎ−ＫＯＨエタノール溶液を添加し、３０分間環流することにより遊離する塩素量を硝酸銀滴定法ににより測定し、試料の重量で除した値である。
【００３２】
実施例１
温度計、冷却管、撹拌器を取り付けたフラスコに窒素ガスパージを施しながら、下記式（３）
【００３３】
【化５】

【００３４】
で表される化合物１４４部、エピクロルヒドリン７４０部、テトラメチルアンモニウムクロライド１０部を仕込み溶解させた。更に４５℃に加熱しフレーク状水酸化ナトリウム（純度９９％）１３５部を１００分かけて分割添加し、その後、更に４５℃で３時間、反応させた。反応終了後、水洗を２回行った後、油層をロータリエバポレーターを使用し１３０℃、５ｍｍＨｇの加熱減圧下で、過剰のエピクロルヒドリンを留去し、残留物に５２０部のメチルイソブチルケトンを加え、溶解した。
【００３５】
更に、このメチルイソブチルケトンの溶液を７０℃に加熱し３０重量％の水酸化ナトリウム水溶液２０部を添加し１時間反応させた後、水洗を繰り返し洗浄液のｐＨを中性とした。更に水層は分離除去し、ロータリーエバポレーターを使用して油層から加熱減圧下メチルイソブチルケトンを留去し下記式（４）
【００３６】
【化６】

【００３７】
（式（４）中、ｎは正数を表し、Ｇはグリシジル基を表す。）
で表される液状のエポキシ樹脂（Ａ）２３２部を得た。得られたエポキシ樹脂のエポキシ当量は１４５ｇ／ｅｑであり、全塩素濃度は４６００ｐｐｍであった。
【００３８】
実施例２
温度計、冷却管、撹拌器を取り付けたフラスコに窒素ガスパージを施しながら、前記式（３）で表される化合物１４４部、エピクロルヒドリン７４０部、ジメチルスルホキシド３７０部を仕込み溶解させた。更に４５℃に加熱しフレーク状水酸化ナトリウム（純度９９％）８１部を１００分かけて分割添加し、その後、更に４５℃で２時間、７０℃で１時間反応させた。反応終了後、ロータリエバポレーターを使用し反応液を１３０℃、５ｍＨｇの加熱減圧下で、過剰のエピクロルヒドリン及びジメチルスルホキシドを留去し、残留物に５２０部のメチルイソブチルケトンを加え、溶解した。
【００３９】
更に、このメチルイソブチルケトンの溶液を７０℃に加熱し３０重量％の水酸化ナトリウム水溶液２０部を添加し１時間反応させた後、水洗を繰り返し洗浄液のｐＨを中性とした。更に水層は分離除去し、ロータリーエバポレーターを使用して油層から加熱減圧下メチルイソブチルケトンを留去し前記式（４）で表される液状のエポキシ樹脂（Ｂ）２２８部を得た。得られたエポキシ樹脂のエポキシ当量は１６５ｇ／ｅｑであり、全塩素濃度は７４０ｐｐｍであった。
【００４０】
実施例３〜４
エポキシ樹脂としてエポキシ樹脂（Ａ）及び（Ｂ）、硬化剤としてカヤハードＭＣＤ（酸無水物系硬化剤、日本化薬（株）製）、硬化促進剤として２−エチル−４−メチル−イミダゾール（２Ｅ４ＭＺ）を用い、表１の配合物の組成の欄に示す組成で配合して混合し、金型に注型した後、８０℃で２時間、１２０℃で２時間、２００℃５時間硬化せしめて試験片を作成し、これを更に微粉砕した。得られた硬化物の粒径を４２メッシュオン、６０メッシュパスの間に揃え、各々５部を採取して５０部のイオン交換水に分散させ、１２１℃で２０時間ＰＣＴ（プレッシャークッカーテスト）を行った。その後水分を濾別し、イオンクロマトグラフィーにより、硬化物中から遊離した塩素イオンの定量を行うと表１のようになった。尚、表１の配合物の組成の欄の数値は部を表す。
【００４１】
【表１】
表１

【００４２】
【発明の効果】
本発明のエポキシ樹脂の製造方法は、従来の製法と異なり高価な金属錯体を触媒として使用しないため、工業的に有利である。また本発明の製造方法で得られたエポキシ樹脂はハロゲン含有量が低いため電気・電子材料等の用途にきわめて有用でありまた、本発明の硬化物は耐熱性、耐水性に優れているため耐熱性、耐水性の要求される広範な分野で用いることができる。具体的には封止材料、積層板、絶縁材料、レジストなどのあらゆる電気・電子材料として有用である。又、成形材料や複合材料の分野にも用いることができる。[0001]
[Industrial applications]
The present invention relates to a method for producing an epoxy resin having a low viscosity and a low halogen content, and a cured product of an epoxy resin composition containing the epoxy resin.
[0002]
[Prior art]
Epoxy resins can be cured with various curing agents to give cured products with excellent mechanical properties, water resistance, chemical resistance, heat resistance, and electrical properties. It is used in a wide range of fields such as materials and casting materials. Conventionally, there is a liquid and solid bisphenol A type epoxy resin obtained by reacting bisphenol A with epichlorohydrin as the epoxy resin most used industrially. In particular, liquid bisphenol A type epoxy resins are used in a wide range of fields because of the operational advantage of having fluidity at room temperature. On the other hand, low-viscosity epoxy resins include polyfunctional alcohol epoxy resins such as hydrogenated bisphenol A type epoxy resin and 1,6-hexanediol epoxy resin, which are used as reactive diluents.
[0003]
[Problems to be solved by the invention]
With the remarkable progress in the electric and electronic fields in recent years, the demand for electric insulating materials used in these fields has become strict, and the appearance of epoxy resins having a low viscosity and a low chlorine content has been awaited. As a low-viscosity epoxy resin, there is an epoxy resin of a linear aliphatic polyfunctional alcohol. However, a cured product thereof has extremely poor heat resistance and has a drawback of high water absorption. Further, as a low-viscosity epoxy resin having excellent physical properties of the cured product, diglycidyl ether of cyclohexane dimethanol can be mentioned, and its production method is described in, for example, JP-A-6-122678. The epoxy resin has a very high chlorine content and is not suitable for use in the electric and electronic fields. Further, this method is industrially disadvantageous because a relatively expensive metal complex is used.
[0004]
[Means for Solving the Problems]
In view of these circumstances, the present inventors have conducted intensive studies in search of an epoxy resin having a low viscosity, a low halogen content, and excellent curing properties.As a result, the epoxy resin obtained by diglycidyl etherification of cyclohexanemethanol by a specific production method has been described above. They have found that the characteristics and effects are satisfied, and have completed the present invention.
[0005]
That is, the present invention provides (1) the following formula (1)
[0006]
Embedded image

[0007]
(In the formula, m represents an integer of 0 to 10, and R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
The following formula (2) obtained by reacting 2.5 to 10 mol of epihalohydrin per equivalent of hydroxyl group of the compound represented by
[0008]
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[0009]
(In the formula, n represents a positive number, m represents an integer of 0 to 10, R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and G represents a glycidyl group.)
[0010]
A method for producing an epoxy resin represented by
(2) The method for producing an epoxy resin according to the above (1), wherein a quaternary ammonium salt is used in the reaction;
(3) The method for producing an epoxy resin according to the above (1), wherein an aprotic polar solvent is used in the reaction.
(4) A cured product of the epoxy resin composition containing the epoxy resin obtained by the production method according to the above (1), (2) or (3).
[0011]
Hereinafter, details of the present invention will be described.
Examples of the method for producing the epoxy resin of the present invention include a method in which the compound represented by the formula (1) is dissolved in a specific amount of epihalohydrin and reacted in the presence of an alkali metal hydroxide.
[0012]
R in the formulas (1) and (2) are each independently present, and specific examples other than the hydrogen atom include a methyl group, an ethyl group, a propyl group, and a butyl group. One or a plurality may exist. Specific examples of the compound of the formula (1) that can be used in the present invention include 2-methyl-1,4-cyclohexanedimethanol, 2,5-dimethyl-1,4-cyclohexanedimethanol, 1,4-cyclohexanedimethanol And the like, but are not limited thereto.
[0013]
In the present invention, the compound represented by the formula (1) is reacted with epihalohydrin. Specific examples of the epihalohydrin that can be used include epichlorohydrin, epibromohydrin, epiiodohydrin and the like, and epichlorohydrin is particularly preferable. The amount of epihalohydrin to be used is generally 2.5 to 10 moles, preferably 3 to 8 moles, per 1 equivalent of the hydroxyl group of the compound represented by the formula (1).
[0014]
In the present invention, a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide or trimethylbenzylammonium chloride is preferably added as a catalyst to a dissolved mixture of the compound represented by the formula (1) and epihalohydrin, and An aqueous solution or solid of a metal hydroxide is added and reacted.
[0015]
The amount of the quaternary ammonium salt used at this time is usually 1 to 10 g, preferably 2 to 8 g, per equivalent of the hydroxyl group of the compound represented by the formula (1).
[0016]
In the present invention, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added to a mixture of the compound represented by the formula (1), epihalohydrin and a quaternary ammonium salt, or 20 to 100 ° C. At a temperature of 1 to 20 hours. In the above reaction, the aqueous solution of the alkali metal hydroxide may be used. In that case, the aqueous solution of the alkali metal hydroxide is continuously added to the reaction mixture, and the solution is continuously added under reduced pressure or normal pressure. In this method, water and epihalohydrin are distilled off, the liquid is further separated, water is removed, and epihalohydrin is continuously returned to the reaction mixture.
[0017]
The amount of the alkali metal hydroxide used in this reaction is usually 1 to 2 mol, preferably 1.1 to 1.8 mol, per 1 equivalent of the hydroxyl group of the compound represented by the formula (1).
[0018]
The reaction can also be carried out by adding an aprotic polar solvent such as dimethyl sulfone or dimethyl sulfoxide instead of the quaternary ammonium salt. When an aprotic polar solvent is added, the amount used is preferably from 5 to 100% by weight, particularly preferably from 10 to 90% by weight, based on the amount of epihalohydrin used.
[0019]
In this reaction, the amount of the alkali metal hydroxide to be used is generally 0.8 to 1.5 mol, preferably 0.9 to 1.1 mol, per equivalent of the hydroxyl group of the compound represented by the formula (1). is there.
[0020]
In these epoxidation reactions, when a quaternary ammonium salt is used, unreacted epihalohydrin is usually removed after washing with water. In addition, when an aprotic polar solvent is used, a washing step is not particularly necessary, and the next epihalohydrin removing step can be performed as it is.
In the above, epihalohydrin (and an aprotic polar solvent) can be removed by a known method, for example, distillation of the product by heating under reduced pressure. The residue after removing epihalohydrin and the like is usually dissolved in an organic solvent. Specific examples of the organic solvent that can be used include methyl isobutyl ketone, benzene, toluene, xylene, and the like, with methyl isobutyl ketone and toluene being preferred. These can be used alone or as a mixture.
[0021]
Thereafter, 0.01 to 0.3 equivalent of an alkali metal hydroxide is added to 1 equivalent of the hydroxyl group of the compound represented by the formula (1) used as a raw material, and the mixture is added at 50 to 80 ° C. for 30 minutes to 3 hours. It is preferable to stir and carry out a dehydrohalogenation reaction. This alkali metal hydroxide is preferably used as a 10 to 40% by weight aqueous solution.
[0022]
After completion of the reaction, the resin solution is washed several times with water, and the organic solvent is distilled off under reduced pressure by heating to obtain the desired epoxy resin represented by the formula (2).
[0023]
The epoxy resin obtained by the present invention is used alone or in combination with other epoxy resins to obtain an epoxy resin composition to which a curing agent is added in the same manner as a normal epoxy resin, and further a curing accelerator is added as necessary. Is cured by heating to obtain a cured product of the present invention. When used together, the proportion of the epoxy resin obtained by the present invention in the total epoxy resin is usually 5% by weight or more, preferably 10% by weight or more. In this case, the epoxy resin to be used is usually a compound having two or more epoxy groups in one molecule. Specific examples of epoxy resins that can be used in combination include phenol novolak epoxy resins, cresol novolak epoxy resins, novolak epoxy resins such as naphthol novolak epoxy resins, triphenylmethane epoxy resins, bisphenol A epoxy resins, and bisphenol F epoxy resins. Epoxy resins obtained from aromatic dihydric phenols such as epoxy resin, bisphenol AD epoxy resin, bisphenol S epoxy resin, bisphenol I epoxy resin, biphenyl epoxy resin, dihydroxybenzene epoxy resin, phthalic acid, and dimer acid Glycidyl ester type epoxy resin by the reaction of epihalohydrin with polybasic acid such as, and polyamine such as diaminodiphenylmethane, isocyanuric acid and epihalohydrin Glycidyl amine-type epoxy resin obtained by reaction. These epoxy resins may be used alone or in combination of two or more.
[0024]
Examples of the curing agent used for obtaining the cured product of the present invention include amine compounds, acid anhydride compounds, amide compounds, phenol compounds, and the like. Specific examples thereof include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide, a polyamide resin synthesized from a dimer of linolenic acid and ethylenediamine, phthalic anhydride, trimellitic anhydride, Pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol novolak, and modified products thereof, imidazole , BF ₃ -amine complexes, guanidine derivatives and the like. These curing agents may be used alone or in combination of two or more.
[0025]
The use amount of these curing agents is preferably 0.7 to 1.2 equivalents to the epoxy group. If the amount is less than 0.7 equivalents or more than 1.2 equivalents with respect to the epoxy group, curing may be incomplete and good cured physical properties may not be obtained.
[0026]
When using the above curing agent, a curing accelerator may be used in combination. Specific examples of the curing accelerator that can be used include, for example, imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, and 1,8-diaza. Tertiary amines such as -bicyclo (5,4,0) undecene-7; phosphines such as triphenylphosphine; and metal compounds such as tin octylate. The curing accelerator is used, if necessary, in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the epoxy resin.
[0027]
The epoxy resin composition in the present invention contains an inorganic filler as needed. Specific examples of the inorganic filler that can be used include silica, alumina, and talc. The inorganic filler is used in an amount occupying 0 to 90% by weight in the epoxy resin composition. Furthermore, the epoxy resin composition of the present invention may contain various compounding agents such as silane coupling agents, release agents such as stearic acid, palmitic acid, zinc stearate, and calcium stearate, and pigments, if necessary. it can.
[0028]
The epoxy resin composition can be obtained by uniformly mixing the components at a predetermined ratio. A cured product can be easily obtained from the epoxy resin composition by a method similar to a conventionally known method. For example, the epoxy resin obtained by the present invention, a curing agent, and if necessary, a curing accelerator, an inorganic filler and other compounding agents are made uniform by using an extruder, a kneader, a roll, or the like, if necessary. The epoxy resin composition is sufficiently mixed to obtain an epoxy resin composition, and the epoxy resin composition is melted, molded using a casting or transfer molding machine, and further heated to 80 to 200 ° C. to obtain a cured product of the present invention. Can be obtained.
[0029]
Further, the epoxy resin composition is dissolved in a solvent, and a prepreg obtained by impregnating a substrate such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, and paper and drying by heating is subjected to hot press molding. A cured product can also be obtained.
[0030]
Specific examples of the solvent that can be used at this time include methyl ethyl ketone, acetone, and methyl isobutyl ketone. The amount of the solvent is usually 10 to 70% by weight, preferably 15% by weight in the mixture of the epoxy resin composition of the present invention and the solvent. An amount occupying ~ 65% by weight is used.
[0031]
【Example】
Next, the present invention will be described in more detail with reference to Examples. In the following, parts are by weight unless otherwise specified. In the examples, the total chlorine concentration is defined as the amount of chlorine released by adding a 1N-KOH ethanol solution to a dioxane solution of a sample and refluxing for 30 minutes by a silver nitrate titration method, and dividing by the weight of the sample. Value.
[0032]
Example 1
The following formula (3) was applied to the flask equipped with the thermometer, the cooling tube, and the stirrer while purging with nitrogen gas.
[0033]
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[0034]
Was charged and dissolved in 144 parts of a compound represented by the following formula, 740 parts of epichlorohydrin, and 10 parts of tetramethylammonium chloride. The mixture was further heated to 45 ° C., and 135 parts of flake-form sodium hydroxide (purity: 99%) was added in portions over 100 minutes. After the completion of the reaction, after washing with water twice, the oil layer was distilled off the excess epichlorohydrin using a rotary evaporator at 130 ° C. under a reduced pressure of 5 mmHg, and 520 parts of methyl isobutyl ketone was added to the residue to dissolve the oil. did.
[0035]
Further, the solution of methyl isobutyl ketone was heated to 70 ° C., 20 parts of a 30% by weight aqueous sodium hydroxide solution was added, and the mixture was allowed to react for 1 hour. Thereafter, washing with water was repeated to make the pH of the washing solution neutral. Further, the aqueous layer was separated and removed, and methyl isobutyl ketone was distilled off from the oil layer under reduced pressure by heating using a rotary evaporator to obtain the following formula (4)
[0036]
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[0037]
(In the formula (4), n represents a positive number, and G represents a glycidyl group.)
(232 parts) of a liquid epoxy resin (A) represented by the following formula: The epoxy equivalent of the obtained epoxy resin was 145 g / eq, and the total chlorine concentration was 4600 ppm.
[0038]
Example 2
A nitrogen gas purge was applied to a flask equipped with a thermometer, a condenser and a stirrer, and 144 parts of the compound represented by the formula (3), 740 parts of epichlorohydrin, and 370 parts of dimethyl sulfoxide were charged and dissolved. The mixture was further heated to 45 ° C., and 81 parts of flake-form sodium hydroxide (purity: 99%) was added in portions over 100 minutes. After completion of the reaction, excess epichlorohydrin and dimethyl sulfoxide were distilled off at 130 ° C. under a reduced pressure of 5 mHg using a rotary evaporator, and 520 parts of methyl isobutyl ketone was added to the residue to dissolve the residue.
[0039]
Further, the solution of methyl isobutyl ketone was heated to 70 ° C., 20 parts of a 30% by weight aqueous sodium hydroxide solution was added, and the mixture was allowed to react for 1 hour. Thereafter, washing with water was repeated to make the pH of the washing solution neutral. Further, the aqueous layer was separated and removed, and methyl isobutyl ketone was distilled off from the oil layer under reduced pressure by heating using a rotary evaporator to obtain 228 parts of a liquid epoxy resin (B) represented by the above formula (4). The epoxy equivalent of the obtained epoxy resin was 165 g / eq, and the total chlorine concentration was 740 ppm.
[0040]
Examples 3 and 4
Epoxy resins (A) and (B) as epoxy resins, Kayahard MCD (acid anhydride-based curing agent, manufactured by Nippon Kayaku Co., Ltd.) as a curing agent, and 2-ethyl-4-methyl-imidazole (2E4MZ) as a curing accelerator ), Mixed and mixed in the composition shown in the column of the composition of the composition in Table 1, and then poured into a mold, and then cured at 80 ° C for 2 hours, 120 ° C for 2 hours, and 200 ° C for 5 hours. A test piece was prepared and further pulverized. The particle size of the obtained cured product was adjusted between 42 mesh-on and 60 mesh passes, 5 parts each were collected and dispersed in 50 parts of ion-exchanged water, and subjected to PCT (pressure cooker test) at 121 ° C. for 20 hours. went. Thereafter, the water was filtered off, and the amount of chloride ion released from the cured product was determined by ion chromatography, as shown in Table 1. The numerical values in the column of the composition of the composition in Table 1 represent parts.
[0041]
[Table 1]
Table 1

[0042]
【The invention's effect】
The method for producing an epoxy resin of the present invention is industrially advantageous because it does not use an expensive metal complex as a catalyst, unlike the conventional production method. Further, the epoxy resin obtained by the production method of the present invention has a low halogen content, so that it is extremely useful for electric and electronic materials, and the cured product of the present invention has excellent heat resistance and water resistance. It can be used in a wide range of fields where water resistance and water resistance are required. Specifically, it is useful as any electric or electronic material such as a sealing material, a laminate, an insulating material, and a resist. It can also be used in the field of molding materials and composite materials.

Claims (3)

The following equation (1)

(Wherein m represents an integer of 0 to 10, R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms) and 2.5 to 10 per equivalent of a hydroxyl group in the compound. Reacting moles of epihalohydrin in the presence of an alkali metal hydroxide;

(In the formula, n represents a positive number, m represents an integer of 0 to 10, R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and G represents a glycidyl group.)
A method for producing an epoxy resin represented by The method for producing an epoxy resin according to claim 1, wherein a quaternary ammonium salt is used in the reaction. The method for producing an epoxy resin according to claim 1, wherein an aprotic polar solvent is used in the reaction.