JP4359952B2 - Anionic latent catalyst and resin composition using the same - Google Patents

Description

【０００６】
式中、Ｒ¹〜Ｒ³は、アルキル基、置換または無置換（以下、置換・無置換と記す）アリール基、および置換・無置換アラルキル基からなる群から選ばれた少なくとも１種を表し、それらは互いに同一であっても異なっていても良い。Ｒ⁴〜Ｒ⁵は、水素、ハロゲン、置換・無置換アルキル基、置換・無置換アリール基、置換・無置換アラルキル基、置換・無置換アシル基、置換・無置換アリーロイル基、およびシアノ基からなる群から選ばれた少なくとも１種を表し、それらは互いに同一であっても異なっていても良い。Ｘは１３族のルイス酸性を有する元素であり、Ｌはエトキシ基、ナフトイロキシ基、フェニル基、トリル基、メシチル基、ペンタフルオロフェニル基、ナフチル基、フェノキシ基、2,6-ジメチルフェノキシ基および2,6-ジ-t-ブチルフェノキシ基からなる群から選ばれた少なくとも１種又は分子内二座配位性置換基の、２，３−ジヒドロキシブタンから誘導された基、カテコール基、アセチルアセトネート基、2,2,6,6-テトラメチル-3,5-ヘプタンジオネート基、3-ヒドロキシ-2-メチル-4H-ピラノ-4-エート基、および9-ビシクロ[3, 3, 1]ノニル基からなる群から選ばれた少なくとも１種を表し、それらは互いに同一であっても異なっていても良い。
【０００７】
【発明の実施の形態】
本発明におけるアニオン潜伏性触媒の置換基Ｒ¹〜Ｒ³は、アルキル、置換・無置換アリール、および置換・無置換アラルキルからなる群から選ばれた少なくとも１種であり、具体的には、メチル、エチル、ブチルなどのアルキル基、フェニル、ナフチル、トリル、アニシルなどのアリール基、ベンジルなどのアラルキル基が例示される。
【０００８】
また、置換基Ｒ⁴〜Ｒ⁵は、水素、ハロゲン、置換・無置換アルキル基、置換・無置換アリール基、置換・無置換アラルキル基、置換・無置換アシル基、置換・無置換アリーロイル基、およびシアノ基からなる群から選ばれた少なくとも１種であり、具体的には、水素、シアノ基の他、フッ素、塩素、臭素、ヨウ素などのハロゲン、メチル、エチル、ブチルなどのアルキル基、あるいは対応するパーフルオロアルキル基、フェニル、ナフチル、トリル、アニシル、ニトロフェニル、シアノフェニルなどの置換・無置換アリール基、ペンタフルオロフェニルなどの対応するパーフルオロアリール基、ベンジルなどのアラルキル基、ホルミル、アセチル、プロピオニル、ベンゾイル、ナフトイル、トルオイル、アニソイル、シアノベンゾイル、ニトロベンゾイルなどのアシル基、アリーロイル基などが例示される。
【０００９】
Ｘは１３族のルイス酸性を示す元素であり、ホウ素、アルミニウム、ガリウム、インジウム、およびタリウムであるが、特にホウ素、アルミニウムが望ましい。しかし、有機ボラン類や有機アルミニウム類は、会合しやすい性質を持つことが知られている。たとえば、ボラン類は二量体のジボランに、アルミニウム類は複核クラスター状に会合する。このことは、本発明における触媒の安定性を低下させる原因となっていた。
【００１０】
そこで会合度を減らすために、Ｌに嵩高い置換基または二座配位子を導入することにより、触媒の安定性を向上させた。具体的にはＬとして、フェニル基、トリル基、メシチル基、ペンタフルオロフェニル基、ベンゾイル基、ナフチル基、ナフトイル基、フェノキシ基、2,6-ジメチルフェノキシ基、2,6-ジ-t-ブチルフェノキシ基、ノルマルプロピル基、イソプロピル基、または相互に結合し環状構造となっている、カテコール基、アセチルアセトネート基、2,2,6,6-テトラメチル-3,5-ヘプタンジオネート基、3-ヒドロキシ-2-メチル-4H-ピラノ-4-エート基、9-ビシクロ[3, 3, 1]ノニル基などが例示される。
【００１１】
本発明のアニオン潜伏性触媒は、通常のアニオン硬化可能な樹脂系で、その優れた触媒活性を示す。具体的には、エポキシ樹脂を初め、マレイミド樹脂、シアネート樹脂、イソシアネート樹脂、アクリレート樹脂などであるが、３級アミン、３級ホスフィン及びその４級塩などで硬化反応するものはすべて含まれる。
【００１２】
次に、第２の発明である樹脂組成物に用いられる、１分子内にエポキシ基を２個以上有する化合物（Ａ）は、１分子内にエポキシ基を２個以上有するものであれば何ら制限はなく、例えば、ビフェニル型エポキシ樹脂、ノボラック型エポキシ樹脂、ナフタレン型エポキシ樹脂など、ビフェノールなどのフェノール類や、フェノール樹脂、ナフトール類などの水酸基に、エピクロロヒドリンを反応させて製造するエポキシ樹脂の他、脂環式エポキシ樹脂のようにオレフィンを過酸によって酸化させエポキシ化したエポキシ樹脂、ハイドロキノン等のジヒドロキシベンゼン類をエピクロロヒドリンでエポキシ化したものも含まれる。
【００１３】
１分子内にフェノール性水酸基を２個以上有する化合物（Ｂ）は、フェノールノボラック樹脂、クレゾールノボラック樹脂、アルキル変性ノボラック樹脂、フェノールアラルキル樹脂、ナフトール類とフェノール類をカルボニル基含有化合物と共縮合した樹脂などが例示されるが、１分子内で芳香族性の環に結合する水素原子が水酸基で２個以上置換された化合物であれば良い。
【００１４】
本発明の、エポキシ基を２個以上有する化合物（Ａ）とフェノール性水酸基を２個以上有する化合物（Ｂ）、および一般式（１）で表されるアニオン潜伏性触媒（Ｃ）を必須成分とする樹脂組成物は、硬化性と保存性が極めて良好であり、電気・電子用途の封止材料として優れた性能を実現できる。また、この樹脂組成物には、必要に応じて、無機充填材や離型剤、カップリング剤等、当業者にて公知の添加剤、副資材を組み合わせることは何らさしつかえない。
【００１５】
【実施例】
以下に、実施例を挙げて本発明を具体的に説明するが、本発明はこれによって何ら限定されるものではない。
【００１６】
（アニオン潜伏性触媒の合成）
本発明におけるアニオン潜伏性触媒の合成は、通常先ず、有機ホスホランを合成し、その後、ルイス酸と接触させて、アニオン性を帯びたリンの隣接炭素をルイス酸に配位させる方法をとる。以下に、典型的な合成例を示す。
【００１７】
（合成例）
塩化カルシウム管つき冷却管を付設した１００mlのナス型フラスコに、メチルトリフェニルホスホニウムブロマイド５.２２ｇと、ジエチルエーテル５０mlを入れ、マグネットスターラで攪拌しながら０℃に冷却し、メチルトリフェニルホスホニウムブロマイドに対して１.１倍モルになるように、フェニルリチウム溶液を滴下する。その後、室温に戻して生成した沈殿を濾過し、得られた濾液を塩化カルシウム管つき冷却管を付設した１００mlのナス型フラスコに入れ、さらにジエチルエーテル５０mlを加え、０℃に冷却攪拌し、生成したホスホランに対して等モルとなるように、トリフェニルボランＴＨＦ溶液をゆっくりと滴下した。その後、室温に戻して１時間攪拌を継続した後、生成した沈殿を濾過し乾燥した。得られた化合物をＤとする。
【００１８】
さらに、上記合成方法に準じて、化合物Ｅ〜Ｈを合成した。化合物Ｄ〜Ｈの化学構造は次に示した通りである。
【００１９】
【化２】

【００２０】
【化３】

【００２１】
【化４】

【００２２】
【化５】

【００２３】
【化６】

【００２４】
（エポキシ樹脂組成物の調製と評価）
エポキシ基を２個以上有する化合物（Ａ）、フェノール性水酸基を２個以上有する化合物（Ｂ）、および前記合成例で作製したアニオン潜伏性触媒（Ｃ）（化合物Ｄ〜Ｈ）を粉砕混合し、１００℃の熱板上で５分間溶融混練した後、冷却粉砕して樹脂組成物のサンプルを調製した。各サンプルについて特性評価のため、硬化トルク（硬化性）、および硬化発熱量残存率（保存性）の測定を行なった。それぞれの評価方法は、下記の通りとした。
【００２５】
１．硬化トルク（硬化性評価）
前記の方法により調製した樹脂組成物を用いて、キュラストメーター（オリエンテック社製、ＪＳＲキュラストメーターＰＳ型）にて、１７５℃、４５秒加熱後のトルクを求める。キュラストメーターにおけるトルクは硬化性のパラメータであり、値の大きい方が硬化性が高いことを示す。
【００２６】
２．硬化発熱量残存率（保存性評価）
前記の方法により調製した樹脂組成物について、初期硬化発熱量（ｍｊ／ｍｇ）、および４０℃３日間保存処理後の硬化発熱量（ｍｊ／ｍｇ）を、昇温速度１０℃／ｍｉｎにて示差熱分析により測定し、初期硬化発熱量に対する保存処理後の硬化発熱量の１００分率（硬化発熱量残存率）を求めた。この値が大きいほど保存性が良好であることを示す。
【００２７】
（実施例１〜５、および比較例１〜２）
合成例で作製した化合物Ｄ〜Ｈ、および比較例として、トリフェニルホスフィンとＤＢＵについて、表１に示した配合により樹脂組成物を調製し、硬化性および保存性の評価を行なった。
【００２８】
評価結果は表１に示した通りで、実施例では硬化性、保存性とも良好で、特に、硬化発熱量残存率はいずれも９５％以上を保っているのに対して、比較例では硬化トルクが０で硬化性が低く、硬化発熱量残存率も６０％あまりと低い値であった。
【００２９】
【表１】

【００３０】
【発明の効果】
本発明のアニオン潜伏性触媒をアニオン硬化可能な樹脂系に用いれば、優れた触媒活性を示し、硬化性と保存性の良好な樹脂組成物が得られ、常温で保管、輸送することができ、さらに、成形時には硬化不良を起こすことがないなどの利点が得られ、また、この樹脂組成物は電気・電子材料として好適で、電気・電子産業分野へのメリットは大きく有用である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an anion latent catalyst for epoxy resins that realizes excellent curability and storage stability, and a resin composition useful in the field of electric and electronic materials using the same.
[0002]
[Prior art]
Anion curing catalysts that have been used for electrical and electronic materials, especially epoxy resin IC encapsulating materials, ie, imidazoles, bicyclic amidines such as DBU (diazabicycloundecene), and tri-substituted phosphines, etc. However, when these catalysts are used for epoxy resin encapsulating materials, the reaction proceeds at room temperature and molding failure may occur due to a decrease in fluidity, so it is essential to store and transport at low temperatures. Yes. In recent years, low molecular crystalline epoxy resins such as biphenyl type epoxy resins have been used as epoxy resins, and more rapid catalyst is required due to the spread of automatic molding. Increasingly, the issue of storability is becoming increasingly important.
[0003]
[Problems to be solved by the invention]
In view of such a situation, the present inventors have intensively studied to propose an anion latent catalyst having a novel structure and function, and as a result, have found an unprecedented new anion latent catalyst and completed the present invention. It was. An object of the present invention is to provide an anionic latent catalyst for epoxy resins that realizes excellent curability and storage stability, and a resin composition useful in the field of electric / electronic materials using the same.
[0004]
[Means for Solving the Problems]
That is, the present invention provides an anion latent catalyst for epoxy resins characterized by having a structure represented by the general formula (1), and further includes a compound (A) having two or more epoxy groups in one molecule, 1 A resin composition characterized by comprising as essential components a compound (B) having two or more phenolic hydroxyl groups in the molecule and the anion latent catalyst for epoxy resin (C).
[0005]
[Chemical 1]

[0006]
In the formula, R ^{1 to} R ³ represent at least one selected from the group consisting of an alkyl group, a substituted or unsubstituted (hereinafter referred to as substituted / unsubstituted) aryl group, and a substituted / unsubstituted aralkyl group, They may be the same or different from each other. R ^{4 to} R ⁵ are hydrogen, halogen, substituted / unsubstituted alkyl group, substituted / unsubstituted aryl group, substituted / unsubstituted aralkyl group, substituted / unsubstituted acyl group, substituted / unsubstituted aryloyl group, and cyano group. Represents at least one selected from the group consisting of, and they may be the same or different. X is an element having Lewis acidity of Group 13, L is an ethoxy group, naphthoyloxy group, phenyl group, tolyl group, mesityl group, pentafluorophenyl group, naphthyl group, phenoxy group, 2,6-dimethylphenoxy group and 2 , A group derived from 2,3-dihydroxybutane, a catechol group, an acetylacetonate of at least one selected from the group consisting of 1,6-di-t-butylphenoxy groups or an intramolecular bidentate substituent Group, 2,2,6,6-tetramethyl-3,5-heptanedionate group, 3-hydroxy-2-methyl-4H-pyrano-4-ate group, and 9-bicyclo [3, 3, 1] It represents at least one selected from the group consisting of nonyl groups , and they may be the same or different.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The substituents R ^{1 to} R ³ of the anionic latent catalyst in the present invention are at least one selected from the group consisting of alkyl, substituted / unsubstituted aryl, and substituted / unsubstituted aralkyl. And alkyl groups such as ethyl and butyl, aryl groups such as phenyl, naphthyl, tolyl and anisyl, and aralkyl groups such as benzyl.
[0008]
Substituents R ^{4 to} R ⁵ are hydrogen, halogen, substituted / unsubstituted alkyl group, substituted / unsubstituted aryl group, substituted / unsubstituted aralkyl group, substituted / unsubstituted acyl group, substituted / unsubstituted aryloyl group, And at least one selected from the group consisting of cyano groups, specifically, hydrogen, cyano groups, halogens such as fluorine, chlorine, bromine and iodine, alkyl groups such as methyl, ethyl and butyl, or Corresponding perfluoroalkyl groups, phenyl, naphthyl, tolyl, anisyl, nitrophenyl, cyanophenyl and other substituted / unsubstituted aryl groups, pentafluorophenyl and other perfluoroaryl groups, benzyl and other aralkyl groups, formyl and acetyl , Propionyl, benzoyl, naphthoyl, toluoyl, anisoyl, cyanobenzoyl, ni Acyl group such as Robenzoiru and aryloyl groups.
[0009]
X is an element exhibiting Lewis acidity of Group 13, and is boron, aluminum, gallium, indium, and thallium, and boron and aluminum are particularly desirable. However, organic boranes and organoaluminums are known to have the property of being easily associated. For example, boranes associate with dimeric diborane and aluminum associates in a binuclear cluster. This has been a cause of lowering the stability of the catalyst in the present invention.
[0010]
Therefore, in order to reduce the degree of association, the stability of the catalyst was improved by introducing a bulky substituent or bidentate ligand into L. Specifically, as L, phenyl group, tolyl group, mesityl group, pentafluorophenyl group, benzoyl group, naphthyl group, naphthoyl group, phenoxy group, 2,6-dimethylphenoxy group, 2,6-di-t-butyl A phenoxy group, a normal propyl group, an isopropyl group, or a catechol group, an acetylacetonate group, a 2,2,6,6-tetramethyl-3,5-heptanedionate group, which are bonded to each other to form a cyclic structure, Examples thereof include a 3-hydroxy-2-methyl-4H-pyrano-4-ate group and a 9-bicyclo [3, 3, 1] nonyl group.
[0011]
The anionic latent catalyst of the present invention is a normal anion-curable resin system and exhibits its excellent catalytic activity. Specific examples include epoxy resins, maleimide resins, cyanate resins, isocyanate resins, and acrylate resins, but all those that undergo a curing reaction with tertiary amines, tertiary phosphines, and quaternary salts thereof are included.
[0012]
Next, the compound (A) having two or more epoxy groups in one molecule used in the resin composition according to the second invention is not limited as long as it has two or more epoxy groups in one molecule. For example, biphenyl type epoxy resin, novolac type epoxy resin, naphthalene type epoxy resin, etc., epoxy resins produced by reacting epichlorohydrin with hydroxyl groups such as phenols such as biphenol, phenol resins, naphthols, etc. In addition, an epoxy resin obtained by oxidizing an olefin with a peracid, such as an alicyclic epoxy resin, and an epoxidized dihydroxybenzene such as hydroquinone with epichlorohydrin are also included.
[0013]
Compound (B) having two or more phenolic hydroxyl groups in one molecule is a phenol novolak resin, a cresol novolak resin, an alkyl-modified novolak resin, a phenol aralkyl resin, a resin obtained by co-condensing a naphthol and a phenol with a carbonyl group-containing compound. Examples thereof include compounds in which two or more hydrogen atoms bonded to an aromatic ring in one molecule are substituted with a hydroxyl group.
[0014]
The essential component is the compound (A) having two or more epoxy groups, the compound (B) having two or more phenolic hydroxyl groups, and the anion latent catalyst (C) represented by the general formula (1) according to the present invention. The resin composition to be used has extremely good curability and storage stability, and can realize excellent performance as a sealing material for electrical / electronic applications. In addition, the resin composition may be combined with additives and auxiliary materials known to those skilled in the art, such as inorganic fillers, mold release agents, and coupling agents, if necessary.
[0015]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
[0016]
(Synthesis of anionic latent catalyst)
In the synthesis of the anionic latent catalyst in the present invention, usually, an organic phosphorane is first synthesized and then brought into contact with a Lewis acid to coordinate an adjacent carbon of phosphorus having an anionic property to the Lewis acid. A typical synthesis example is shown below.
[0017]
(Synthesis example)
In a 100 ml eggplant-shaped flask equipped with a condenser tube with a calcium chloride tube, 5.22 g of methyltriphenylphosphonium bromide and 50 ml of diethyl ether are added and cooled to 0 ° C. while stirring with a magnetic stirrer. On the other hand, the phenyllithium solution is added dropwise so that the molar ratio is 1.1 times. Thereafter, the precipitate formed after returning to room temperature is filtered, and the obtained filtrate is put into a 100 ml eggplant-shaped flask equipped with a condenser tube with a calcium chloride tube, 50 ml of diethyl ether is further added, and the mixture is cooled to 0 ° C. and stirred. The triphenylborane THF solution was slowly added dropwise so as to be equimolar with respect to the phosphorane. Then, after returning to room temperature and continuing stirring for 1 hour, the produced | generated precipitation was filtered and dried. Let D be the resulting compound.
[0018]
Furthermore, compounds E to H were synthesized according to the above synthesis method. The chemical structures of compounds D to H are as shown below.
[0019]
[Chemical formula 2]

[0020]
[Chemical 3]

[0021]
[Formula 4]

[0022]
[Chemical formula 5]

[0023]
[Chemical 6]

[0024]
(Preparation and evaluation of epoxy resin composition)
The compound (A) having two or more epoxy groups, the compound (B) having two or more phenolic hydroxyl groups, and the anion latent catalyst (C) (compounds D to H) prepared in the above synthesis examples were pulverized and mixed. After melt-kneading on a hot plate at 100 ° C. for 5 minutes, the mixture was cooled and crushed to prepare a resin composition sample. In order to evaluate the characteristics of each sample, the curing torque (curability) and the curing heat generation residual ratio (storability) were measured. Each evaluation method was as follows.
[0025]
1. Curing torque (curability evaluation)
Using the resin composition prepared by the above method, the torque after heating at 175 ° C. for 45 seconds is obtained with a curast meter (manufactured by Orientec Co., Ltd., JSR curast meter PS type). The torque in the curast meter is a curability parameter, and a larger value indicates higher curability.
[0026]
2. Curing heat generation residual rate (preservation evaluation)
Regarding the resin composition prepared by the above-described method, the initial curing calorific value (mj / mg) and the curing calorific value (mj / mg) after storage at 40 ° C. for 3 days are differentially shown at a heating rate of 10 ° C./min. It was measured by thermal analysis, and a 100-minute rate (curing heat generation residual rate) of the curing heat generation after the storage treatment with respect to the initial curing heat generation was determined. The larger this value, the better the storage stability.
[0027]
(Examples 1-5 and Comparative Examples 1-2)
As compounds D to H prepared in the synthesis examples and comparative examples, triphenylphosphine and DBU were prepared with the composition shown in Table 1 and evaluated for curability and storage stability.
[0028]
The evaluation results are as shown in Table 1. In the examples, both curability and storage stability are good, and in particular, the curing heat generation amount residual ratio is maintained at 95% or more. Was 0, the curability was low, and the residual rate of curing heat generation was as low as 60%.
[0029]
[Table 1]

[0030]
【The invention's effect】
If the anionic latent catalyst of the present invention is used in an anion-curable resin system, a resin composition having excellent catalytic activity and good curability and storage stability can be obtained, and can be stored and transported at room temperature. Furthermore, there are obtained advantages such as no occurrence of poor curing at the time of molding, and this resin composition is suitable as an electric / electronic material, and its merit for the electric / electronic industry is greatly useful.

Claims (3)

An anionic latent catalyst for an epoxy resin having a structure represented by the general formula (1).

In the formula, R ^{1 to} R ³ represent at least one selected from the group consisting of an alkyl group, a substituted or unsubstituted (hereinafter referred to as substituted / unsubstituted) aryl group, and a substituted / unsubstituted aralkyl group, They may be the same or different from each other. R ^{4 to} R ⁵ are hydrogen, halogen, substituted / unsubstituted alkyl group, substituted / unsubstituted aryl group, substituted / unsubstituted aralkyl group, substituted / unsubstituted acyl group, substituted / unsubstituted aryloyl group, and cyano group. Represents at least one selected from the group consisting of, and they may be the same or different. X is an element having Lewis acidity of Group 13, L is an ethoxy group, naphthoyloxy group, phenyl group, tolyl group, mesityl group, pentafluorophenyl group, naphthyl group, phenoxy group, 2,6-dimethylphenoxy group and 2 Represents at least one selected from the group consisting of 1,6-di-t-butylphenoxy groups , which may be the same or different. An anionic latent catalyst for an epoxy resin having a structure represented by the general formula (1).

In the formula, R ^{1 to} R ³ represent at least one selected from the group consisting of an alkyl group, a substituted or unsubstituted (hereinafter referred to as substituted / unsubstituted) aryl group, and a substituted / unsubstituted aralkyl group, They may be the same or different from each other. R ^{4 to} R ⁵ are hydrogen, halogen, substituted / unsubstituted alkyl group, substituted / unsubstituted aryl group, substituted / unsubstituted aralkyl group, substituted / unsubstituted acyl group, substituted / unsubstituted aryloyl group, and cyano group. Represents at least one selected from the group consisting of, and they may be the same or different. X is an element having Lewis acidity of Group 13, L is an intramolecular bidentate substituent, a group derived from 2,3-dihydroxybutane, a catechol group, an acetylacetonate group, 2,2, From the group consisting of 6,6-tetramethyl-3,5-heptanedioate group, 3-hydroxy-2-methyl-4H-pyrano-4-ate group, and 9-bicyclo [3, 3, 1] nonyl group It represents at least one selected , and they may be the same or different from each other . The compound (A) having two or more epoxy groups in one molecule, the compound (B) having two or more phenolic hydroxyl groups in one molecule, and the anion latency for an epoxy resin according to claim 1 or 2 A resin composition comprising a catalyst (C) as an essential component.