【発明の詳細な説明】[Detailed description of the invention]
本発明は、成形加工時に成形金型の隙間から発
生するバリ特に厚みが30μ以下の薄いバリを大幅
に減少させた成形性に優れるエポキシ樹脂組成物
及びその製造方法に係り、本発明の特徴はバリ防
止のために超微粒子シリカ粉末を適量添加するこ
と及びこの超微粒子シリカ粉末を有効に作用させ
るため均一分散特に樹脂中に均一分散させるとこ
ろにある。
近年、電子機器業界は質的及び量的に急速な発
展をとげ、膨大な数量の高信頼性電子部品が要求
されるようになつてきた。この結果、これら電子
部品用のエポキシ樹脂成形材料には、成形サイク
ルの短縮及び信頼性の向上が要求されてきた。
これら要求を解決するための問題点の中で最も
重要なことの一つは成形時に発生するバリ特に厚
みが30μ以下の薄いバリを防止することである。
即ちバリが発生するとこのバリを除去する工程を
要し生産性低下につながるだけでなくバリの除去
程度により電子部品の性能が異ることもあるため
であり、特にバリの中でも厚みが30μ以下の薄い
バリは除去が難しいため成形合理化及び成形品の
品質安定化の妨げとなつていた。
本発明の発明者らの研究によると、バリは厚み
が30μを超える厚いバリ（以下厚バリと称す
る。）と30μ以下の薄いバリ（以下薄バリと称す
る。）の２種に大別できることが判つた。即ち、
厚バリは組成的には、エポキシ樹脂組成物の成分
比率に近いが、薄バリはエポキシ樹脂組成物の成
分比率とは異なり樹脂分が多く組成上偏りがある
ことが判つた。このためバリの中でも薄バリは、
わずかな隙間からも発生するだけでなく粘着性が
強いため除去することが難しかつた。従来のバリ
止め技術もこの薄バリにはほとんど効果がなく、
例えば、密着型のバリ止め金型は使用時間の増加
に従つて金型の隙間が大きくなり効果を失つたり
エポキシ樹脂組成物の硬化性を高めるとバリ発生
は減少するが充填性が悪くなる等の問題があつた
ので、薄バリを防止する方法や薄バリの発生しな
いエポキシ樹脂組成物が望まれていた。
本発明は、従来の技術では解決できず成形合理
化及び成形品の品質安定化の妨げとなつていた薄
バリの発生を防止したエポキシ樹脂組成物及びそ
の製造方法を提供するものである。本発明の発明
者らは、樹脂との相溶性が良く樹脂粘度を増大さ
せ且つ薄バリ厚みにほぼ等しい形状を有する超微
粒子シリカ粉末が薄バリ防止に有効であることを
見い出したものである。
本発明は粒子径が５〜30ｍμなる超微粒子シリ
カ粉末を全組成に対して0.2〜2.0％含むことを特
徴とするエポキシ樹脂、硬化剤、硬化促進剤、充
填材、離型剤、顔料、難燃剤、表面処理剤等から
成るエポキシ樹脂組成物及び全組成に対して0.2
〜2.0重量％の粒子径５〜30ｍμの超微粒子シリ
カ粉末を使用する原材料の一種又は二種以上の一
部又は全部と予備混合し、さらに残りの原料と混
合混練することを特徴とするエポキシ樹脂、硬化
剤、硬化促進剤、充填材、離型剤、顔料、難燃
剤、表面処理剤等から成るエポキシ樹脂組成物の
製造方法に係るものである。シリカ粉末の粒径が
５ｍμ未満では金型の間隙より洩れてしまうため
効果がなく又粒径が30ｍμより大きいと樹脂の増
粘作用を失うため薄バリには効果がなくなる。又
粒径が５〜30ｍμでも樹脂との相溶性が悪いと増
粘作用は示さないのでシリカ粉末であることが必
要である。例えば、炭素の超微粒子は薄バリ効果
を示さない。さらに、超微粒子シリカ粉末の使用
量が0.2〜2.0％重量％であることが必要である。
0.2重量％未満では絶対量の不足及び分散性の問
題よりバリ止め効果が小さく且つ不均一なためエ
ポキシ樹脂組成物の信頼性が低下する。又、2.0
％を超えるとエポキシ樹脂組成物の特性−例えば
熱膨張特性等−が変化するだけでなく流動性も低
下するためである。ここでいうところのエポキシ
樹脂組成物は通常エポキシ樹脂、硬化剤、充填
材、離型剤、硬化促進剤、顔料、表面処理剤、難
燃剤等より成る混合混練物のことをいう。エポキ
シ樹脂とはエポキシ基を有するもの全般をいい、
例えば、ビスフエノル型エポキシ樹脂、フエノー
ルノボラツク型エポキシ樹脂、クレゾールノボラ
ツク型エポキシ樹脂、トリアジン核含有エポキシ
樹脂、グリシジルイソシアネレート樹脂等を挙げ
ることができる。
硬化剤とは、エポキシ樹脂を硬化させるもの全
般をいい、例えば、フエノールノボラツク、オル
トクレゾールノボラツク等のフエノーノボラツク
類、テトラクロル無水フタル酸（TCPA）、テト
ラハイドロ無水フタル酸（THPA）、ヘキサハイ
ドロ無水フタル酸（HHPA）等の酸無水物、ジシ
アンジアミド（DDA）、ジアミノジフエニルメタ
ン（DDM）等のアミン類を挙げることができ
る。
硬化促進剤とは、エポキシ樹脂と硬化剤の反応
を促進するもの全般をいい、例えば、モノジメチ
ルアミノメチルフエノール、ピペラジン、２・
３・４・６・７・８・９・10−オクタハイドロ−
ピラミド（１・２−ａ）アゼピン等の第３級アミ
ン類、オクチルホスフイン、ジフエニルホスフイ
ン、ブチルフエニルホスフイン、トリフエニルホ
スフイン、トリシクロヘキシルホスフイン等の有
機ホスフイン化合物、２−フエニルイミダゾール
（2PZ）、２エチル４メチルイミダゾール
（2E4MZ）、１−ベンジルイミダゾール（1BZ）、
２メチルイミダゾール（2MZ）等のイミダゾール
類等を挙げることができる。
充填材としては例えば、シリカ、ガラス、炭酸
カルシウム、マイカ、クレー、アルミナ、アスベ
スト、水酸化アルミニウム、水酸化マグネシウ
ム、を挙げることができる。
難燃剤としては、例えば、三酸化アンチモン、
四三酸化アンチモン等のアンチモン類、ホウ類、
無水ホウ酸、ホウ酸亜塩等のホウ素化合物を挙げ
ることができる。
又これら充填材類は必要によりエポキシシラ
ン、アミノシラン、ビニルシラン、アルキルシラ
ン等のシランカツプリング剤やチタンカツプリン
グ剤等の表面処理剤によりその表面を改質しても
よい。
離型剤としては、カルナバワツクス、ステアリ
ン酸、ステアリン酸塩類、ポリエチレンワツクス
等が挙げられる。
特にエポキシ樹脂低圧封入成形材料用には、エ
ポキシ樹脂は軟化点が80℃以下のオルトクレゾー
ルノボラツク型エポキシ樹脂、硬化剤は軟化点が
105℃以下のフエノールノボラツク、充填材はシ
リカ、表面処理剤はエポキシシラン、難燃剤は酸
化アンチモンを使用するのが望ましい。
さらに、超微粒子シリカ粉末による薄バリ防止
効果は分散性が大きく支配するので、予め原材料
の一種又は二種以上の一部又は全部と充分に混合
し、さらに残りの原材料と混合混練し製造するこ
とが必要である。分散性が悪いとバリ止め効果が
小さく且つ不均一なためエポキシ樹脂組成物の信
頼性が低下する。この予備混合は、エポキシ樹脂
や硬化剤といつた樹脂原料と共に行うことが望ま
しい。又、予備混合装置はボールミルや流動層を
用いるのが望ましい。これらは超微粒子シリカ粉
末の分散性及び樹脂の増粘作用を強めバリ止め効
果を最大限に高めるものである。
本発明により提供されるエポキシ樹脂組成物を
使用すると、流動性・充填性に優れるだけでなく
バリ発生も極めて少いため成形サイクルの短縮等
の成形合理化が可能となる。又、成形性に優れる
ため、得られる成形品の特性が安定する等の利点
がある。このように本発明で提供されるエポキシ
樹脂組成物は産業上極めて有益なものであり、そ
の製造法も産業上重要な意味をもつ。以下、具体
例で説明する。
具体例で使用した原料は、
シリカ粉末：龍森(株)製 溶融シリカ 平均粒径
５μ
表面処理剤：信越化学(株)製 KBM−403
フエノールノボラツク：軟化点100℃のもの
離型剤：ヘキストワツクスOP
硬化促進剤：四国化成(株)製 1B2MZ
顔料：三菱化成(株)製 カーボンブラツク
難燃剤：住友金属鉱山(株)製 三酸化アンチモン
エポキシ樹脂：東都化成(株)製 ESCN−220LC
であり、以下重量部を部で表わす。
実施例 １
フエノールノボラツク10部、離型剤１部及び粒
子径30ｍμの超微粒子シリカ粉末0.2部の微粉砕
混合物、並びにシリカ粉末64部、表面処理剤１
部、硬化促進剤0.5部、顔料0.3部、難燃剤３部、
及びエポキシ樹脂をヘンシエルミキサーで混合し
た。この後80〜100℃の熱ロールで５分間混合し
半導体封止用のエポキシ樹脂組成物を得た。この
組成物の165℃熱板上でのゲルタイム（以下ゲル
タイムと称する。）は45秒であり、ブラベンダー
プラストグラフによる165℃溶融安定時間（以下
ブラベンダー安定時間と称する。）は200秒であつ
た。又、薄バリ判定用スリツト金型スリツト幅20
μによる薄バリ長さは0.5mmであつた。さらに成
形歩留は99.5％であつた。この組成物は、従来の
同種比較例１に示したようなエポキシ樹脂組成物
に比べ流動性は同等であるが、薄バリ発生が少く
且つ成形歩留が優れた。
実施例 ２
シリカ粉末を62部、超微粒子シリカ粉末を２
部、顔料を0.5部と混合重量を変更した以外は実
施例１と同様に製造したエポキシ樹脂組成物の流
動特性はゲルタイム43秒、ブラベンダー安定時間
195秒であつた。又薄バリ長さは0.2mm、さらに成
形歩留は99.3％であつた。
実施例 ３
超微粒子シリカ粉末の粒子径を５ｍμにした以
外は、実施例１と同様に製造したエポキシ樹脂組
成物のゲルタイムは47秒、ブラベンダー安定時間
210秒、薄バリ長さ0.6mm、成形歩留は99.8％であ
つた。
実施例 ４
超微粒子シリカ粉末の粒子径を５ｍμにした以
外は実施例２と同様に製造したエポキシ樹脂組成
物のゲルタイムは49秒、ブラベンダー安定時間
190秒、薄バリ長さ0.2mm、成形歩留は99.5％であ
つた。
実施例 ５
シリカ粉末（粒子径５μ）63部、表面処理剤１
部とアシン系硬化剤10部、離型剤１部、粒子径15
ｍμの超微粒子シリカ粉末１部の予備混合物及び
硬化促進剤１部、顔料0.5部、難燃剤３部、エポ
キシ樹脂20部をヘンシエルミキサーで混合し、さ
らに80〜100℃の熱ロールで３分間混練しエポキ
シ樹脂組成物を得た。この組成物のゲルタイムは
40秒、ブラベンダー安定時間は180秒であつた。
又、薄バリ長さは0.1mm、さらに成形歩留は99.3
％であつた。これは比較例に比べ薄バリが少なく
且つ歩留が高い。
比較例 １
超微粒子シリカ粉末を含まないこと以外は全て
実施例１と同一条件で製造したエポキシ樹脂組成
物の流動特性はゲルタイム45秒、ブラベンダー安
定時間205秒であつた。又、薄バリ長さは６mm、
さらに成形歩留は95％であつた。実施例に比べ薄
バリ・成形歩留の点で劣る。
比較例 ２
超微粒子シリカ粉末の粒子径を40ｍμとした以
外は実施例２と同様に製造したエポキシ樹脂組成
物のゲルタイムは46秒、ブラベンダー安定時間
200秒、薄バリ長さ５mm、成形歩留94％であつ
た。
比較例 ３
超微粒子シリカ粉末の粒子径を３ｍμとした以
外は実施例２と同様に製造したエポキシ樹脂組成
物のゲルタイムは44秒、ブラベンダー安定時間
200秒、薄バリ長さ４mm、成形歩留96％であつ
た。
比較例 ４
超微粒子シリカ粉末を３％使用した以外は全て
実施例５と同一条件で製造したエポキシ樹脂組成
物の流動特性は、ゲルタイム35秒、ブラベンダー
安定時間120秒であり、薄バリ長さは0.2mm、成形
歩留は94％であつた。実施例５に比べブラベンダ
ー安定時間が短く成形歩留が悪かつた。又、従来
のエポキシ樹脂組成物に比べ線膨張係数が0.5×
10-51／℃大きく、ガラス転移温度も８℃低く品
質で劣る。
比較例 ５
超微粒子シリカ粉末を含まないこと以外は実施
例５と同じ原材料を使用し、80〜100℃の熱ロー
ルで実施例５の３倍以上10分間混練しエポキシ樹
脂組成物を得た。この組成物のゲルタイムは21
秒、ブラベンダー安定時間は95秒と短く実施例と
比べ流動性で劣る。又薄バリ長さは0.3mmと実施
例同等であつたが成形歩留は43％と極めて低かつ
た。さらに、成形品の信頼性にも欠けた。
比較例 ６
実施例４と同じ原材料を使用したが実施例１と
は異り予備混合をせずに全原材料を同時にヘンシ
エルで混合しさらにコニーダーで混練しエポキシ
樹脂組成物を得た。この組成物の流動特性は実施
例１と同等であつたが、薄バリ長さは0.3ミリか
ら５ミリまでばらつき又成形歩留も96％から99％
までばらつき信頼性に欠ける。
以上の例を表にしてまとめると次のようにな
る。
The present invention relates to an epoxy resin composition with excellent moldability that significantly reduces burrs generated from gaps in a molding die during molding, especially thin burrs with a thickness of 30μ or less, and a method for producing the same. In order to prevent burrs, an appropriate amount of ultrafine silica powder must be added, and in order for this ultrafine silica powder to work effectively, it must be uniformly dispersed, particularly in the resin. In recent years, the electronic equipment industry has undergone rapid qualitative and quantitative development, and a huge number of highly reliable electronic components have come to be required. As a result, epoxy resin molding materials for these electronic components are required to shorten the molding cycle and improve reliability. One of the most important issues in solving these demands is to prevent burrs that occur during molding, especially thin burrs with a thickness of 30 μm or less.
In other words, when burrs occur, a process is required to remove the burrs, which not only leads to a decrease in productivity, but also the performance of electronic components may differ depending on the degree of burr removal. Since thin burrs are difficult to remove, they have been an obstacle to streamlining molding and stabilizing the quality of molded products. According to research conducted by the inventors of the present invention, burrs can be roughly divided into two types: thick burrs with a thickness of more than 30μ (hereinafter referred to as thick burrs) and thin burrs with a thickness of 30μ or less (hereinafter referred to as thin burrs). I understand. That is,
It was found that thick burrs have a composition close to the component ratio of the epoxy resin composition, but thin burrs have a large resin content and are biased in composition, unlike the component ratio of the epoxy resin composition. For this reason, among burrs, thin burrs are
Not only does it occur from even the smallest gaps, but it is also difficult to remove due to its strong adhesiveness. Conventional burr prevention technology has little effect on this thin burr,
For example, a close-fitting burr-preventing mold loses its effectiveness as the gap between the molds becomes larger as the usage time increases, and increasing the curing of the epoxy resin composition reduces the occurrence of burrs but worsens the filling properties. Because of these problems, a method for preventing thin burrs and an epoxy resin composition that does not generate thin burrs have been desired. The present invention provides an epoxy resin composition and a method for producing the same, which prevent the occurrence of thin burrs, which cannot be solved by conventional techniques and which hinders the rationalization of molding and the stabilization of the quality of molded products. The inventors of the present invention have discovered that ultrafine silica powder, which has good compatibility with resin, increases resin viscosity, and has a shape approximately equal to the thickness of thin burrs, is effective in preventing thin burrs. The present invention shows the epoxy resin, hardening agent, curing accelerator, filling material, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, pigment, a particle diameter of 5 to 30 mμ. 0.2 for epoxy resin compositions and all compositions consisting of fuel agents, surface treatment agents, etc.
An epoxy resin characterized by premixing ~2.0% by weight of ultrafine silica powder with a particle size of 5 to 30 mμ with part or all of one or more raw materials, and further mixing and kneading with the remaining raw materials. The present invention relates to a method for producing an epoxy resin composition comprising a curing agent, a curing accelerator, a filler, a mold release agent, a pigment, a flame retardant, a surface treatment agent, and the like. If the particle size of the silica powder is less than 5 mμ, it will leak from the gap between the molds and is therefore ineffective, and if the particle size is larger than 30 mμ, the thickening effect of the resin will be lost, making it ineffective for thin burrs. Furthermore, even if the particle size is 5 to 30 mμ, if the compatibility with the resin is poor, the thickening effect will not be exhibited, so it is necessary to use silica powder. For example, ultrafine carbon particles do not exhibit a thin burr effect. Furthermore, it is necessary that the amount of ultrafine silica powder used is 0.2 to 2.0% by weight.
If it is less than 0.2% by weight, the reliability of the epoxy resin composition decreases because the anti-burr effect is small and non-uniform due to insufficient absolute amount and problems with dispersibility. Also, 2.0
This is because if it exceeds %, not only the properties of the epoxy resin composition such as thermal expansion properties change, but also the fluidity decreases. The epoxy resin composition as used herein generally refers to a mixed and kneaded product consisting of an epoxy resin, a curing agent, a filler, a mold release agent, a curing accelerator, a pigment, a surface treatment agent, a flame retardant, and the like. Epoxy resin refers to anything that has an epoxy group,
Examples include bisphenol type epoxy resins, phenol novolak type epoxy resins, cresol novolak type epoxy resins, triazine nucleus-containing epoxy resins, glycidyl isocyanate resins, and the like. The hardening agent refers to all substances that harden epoxy resins, such as phenol novolaks such as phenol novolak and orthocresol novolak, tetrachlorophthalic anhydride (TCPA), tetrahydrophthalic anhydride (THPA), Examples include acid anhydrides such as hexahydrophthalic anhydride (HHPA), and amines such as dicyandiamide (DDA) and diaminodiphenylmethane (DDM). A curing accelerator refers to any substance that accelerates the reaction between an epoxy resin and a curing agent, such as monodimethylaminomethylphenol, piperazine, 2.
3, 4, 6, 7, 8, 9, 10-octahydro-
Pyramide (1,2-a) Tertiary amines such as azepine, organic phosphine compounds such as octylphosphine, diphenylphosphine, butylphenylphosphine, triphenylphosphine, tricyclohexylphosphine, 2-phenylphosphine, etc. Enylimidazole (2PZ), 2ethyl4methylimidazole (2E4MZ), 1-benzylimidazole (1BZ),
Examples include imidazoles such as 2-methylimidazole (2MZ). Examples of fillers include silica, glass, calcium carbonate, mica, clay, alumina, asbestos, aluminum hydroxide, and magnesium hydroxide. Examples of flame retardants include antimony trioxide,
Antimony compounds such as triantimony tetraoxide, boron compounds,
Examples include boron compounds such as boric anhydride and boric acid subsalts. The surface of these fillers may be modified, if necessary, with a surface treatment agent such as a silane coupling agent such as epoxysilane, aminosilane, vinylsilane, or alkylsilane or a titanium coupling agent. Examples of the mold release agent include carnauba wax, stearic acid, stearates, polyethylene wax, and the like. In particular, for epoxy resin low-pressure encapsulation molding materials, the epoxy resin is an orthocresol novolak type epoxy resin with a softening point of 80℃ or less, and the hardening agent is a
It is desirable to use phenol novolac at 105°C or lower, silica as the filler, epoxy silane as the surface treatment agent, and antimony oxide as the flame retardant. Furthermore, since the thin burr prevention effect of ultrafine silica powder is largely determined by its dispersibility, it must be thoroughly mixed with part or all of one or more raw materials in advance, and then mixed and kneaded with the remaining raw materials to manufacture. is necessary. If the dispersibility is poor, the anti-burr effect will be small and non-uniform, resulting in a decrease in the reliability of the epoxy resin composition. This premixing is preferably performed together with resin raw materials such as epoxy resin and curing agent. Further, it is preferable to use a ball mill or a fluidized bed as the premixing device. These enhance the dispersibility of the ultrafine silica powder and the thickening effect of the resin, thereby maximizing the anti-burr effect. When the epoxy resin composition provided by the present invention is used, it not only has excellent fluidity and filling properties, but also has extremely low burr generation, making it possible to streamline molding such as shortening the molding cycle. Furthermore, since it has excellent moldability, it has the advantage that the properties of the obtained molded product are stable. As described above, the epoxy resin composition provided by the present invention is extremely useful industrially, and the method for producing it also has important industrial significance. A specific example will be explained below. The raw materials used in the specific examples are: Silica powder: Fused silica manufactured by Ryumori Co., Ltd. Average particle size
5μ Surface treatment agent: KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd. Phenol novolak: Softening point 100℃ Mold release agent: Hoechstwax OP Curing accelerator: 1B2MZ manufactured by Shikoku Kasei Co., Ltd. Pigment: Mitsubishi Kasei Co., Ltd. Carbon Black flame retardant: manufactured by Sumitomo Metal Mining Co., Ltd. Antimony trioxide epoxy resin: manufactured by Toto Kasei Co., Ltd. ESCN-220LC, below, parts by weight are expressed in parts. Example 1 A finely ground mixture of 10 parts of phenol novolac, 1 part of a mold release agent, and 0.2 parts of ultrafine silica powder with a particle size of 30 mμ, as well as 64 parts of silica powder and 1 part of a surface treatment agent.
part, curing accelerator 0.5 part, pigment 0.3 part, flame retardant 3 parts,
and epoxy resin were mixed in a Henschel mixer. Thereafter, the mixture was mixed for 5 minutes using a heated roll at 80 to 100°C to obtain an epoxy resin composition for semiconductor encapsulation. The gel time of this composition on a 165°C hot plate (hereinafter referred to as gel time) was 45 seconds, and the 165°C melting stability time (hereinafter referred to as Brabender stability time) by Brabender plastography was 200 seconds. Ta. In addition, the slit mold slit width for thin burr determination is 20
The thin burr length due to μ was 0.5 mm. Furthermore, the molding yield was 99.5%. This composition had the same fluidity as the conventional epoxy resin composition shown in Comparative Example 1 of the same type, but produced fewer thin burrs and had an excellent molding yield. Example 2 62 parts of silica powder, 2 parts of ultrafine silica powder
The flow characteristics of the epoxy resin composition prepared in the same manner as in Example 1 except that the pigment was added to 0.5 parts and the mixing weight was changed were as follows: gel time: 43 seconds, Brabender stability time:
It took 195 seconds. The thin burr length was 0.2 mm, and the molding yield was 99.3%. Example 3 An epoxy resin composition produced in the same manner as in Example 1 except that the particle size of the ultrafine silica powder was 5 mμ had a gel time of 47 seconds and a Brabender stability time.
The molding time was 210 seconds, the length of the thin burr was 0.6 mm, and the molding yield was 99.8%. Example 4 An epoxy resin composition produced in the same manner as Example 2 except that the particle size of the ultrafine silica powder was 5 mμ had a gel time of 49 seconds and a Brabender stability time.
It took 190 seconds, the length of the thin burr was 0.2 mm, and the molding yield was 99.5%. Example 5 63 parts of silica powder (particle size 5μ), 1 surface treatment agent
part, 10 parts of acine curing agent, 1 part of mold release agent, particle size 15
A premix of 1 part of mμ ultrafine silica powder, 1 part of curing accelerator, 0.5 part of pigment, 3 parts of flame retardant, and 20 parts of epoxy resin were mixed in a Henschel mixer, and then heated with a heated roll at 80 to 100°C for 3 minutes. The mixture was kneaded to obtain an epoxy resin composition. The gel time of this composition is
40 seconds, and the Brabender stabilization time was 180 seconds.
In addition, the thin burr length is 0.1mm, and the molding yield is 99.3
It was %. This has fewer thin burrs and a higher yield than the comparative example. Comparative Example 1 An epoxy resin composition produced under the same conditions as in Example 1 except that it did not contain ultrafine silica powder had a gel time of 45 seconds and a Brabender stability time of 205 seconds. Also, the thin burr length is 6mm,
Furthermore, the molding yield was 95%. Inferior to Examples in terms of thin burrs and molding yield. Comparative Example 2 An epoxy resin composition produced in the same manner as in Example 2 except that the particle size of the ultrafine silica powder was 40 mμ had a gel time of 46 seconds and a Brabender stability time.
200 seconds, a thin burr length of 5 mm, and a molding yield of 94%. Comparative Example 3 An epoxy resin composition produced in the same manner as in Example 2 except that the particle size of the ultrafine silica powder was 3 mμ had a gel time of 44 seconds and a Brabender stability time.
200 seconds, a thin burr length of 4 mm, and a molding yield of 96%. Comparative Example 4 The flow characteristics of an epoxy resin composition manufactured under the same conditions as in Example 5 except that 3% of ultrafine silica powder was used were a gel time of 35 seconds, a Brabender stability time of 120 seconds, and a thin burr length. was 0.2 mm, and the molding yield was 94%. Compared to Example 5, the Brabender stabilization time was short and the molding yield was poor. In addition, the linear expansion coefficient is 0.5× compared to conventional epoxy resin compositions.
10 -5 1/℃ higher, the glass transition temperature is 8℃ lower, and the quality is inferior. Comparative Example 5 The same raw materials as in Example 5 were used except that the ultrafine silica powder was not included, and the mixture was kneaded for 10 minutes using heated rolls at 80 to 100° C. for a time more than three times that of Example 5 to obtain an epoxy resin composition. The gel time of this composition is 21
The Brabender stabilization time was as short as 95 seconds, and the fluidity was inferior to that of the Examples. Although the thin burr length was 0.3 mm, which was the same as in the example, the molding yield was extremely low at 43%. Furthermore, the reliability of the molded product was also lacking. Comparative Example 6 The same raw materials as in Example 4 were used, but unlike Example 1, all the raw materials were mixed at the same time in a Henschel without premixing, and then kneaded in a co-kneader to obtain an epoxy resin composition. The flow characteristics of this composition were the same as in Example 1, but the thin burr length varied from 0.3 mm to 5 mm, and the molding yield was 96% to 99%.
It is unreliable and varies up to The above examples can be summarized in a table as follows.
【表】【table】
【表】
本発明による実施例が最も優れ、産業上極めて
有用なことがわかる。[Table] It can be seen that the examples according to the present invention are the best and are extremely useful industrially.