JP4499346B2 - Red phosphorus particle-containing resin composition, prepreg using the resin composition, laminated board, multilayer printed board - Google Patents

Description

（式中、Ｒは置換基を有していてもよい炭化水素骨格を、Ｒ²、Ｒ³、Ｒ⁴は互いに異なっていてもよい水素原子または炭素数１〜６の炭化水素基を、Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｒ⁸は互いに異なっていてもよい水素原子または炭素数１〜２０の炭化水素基を、ｎは２以上の整数を表す）で示される多官能のスチレン基を有する重量平均分子量１０００以下の架橋成分を含有し、かつ、赤燐粒子を含有する赤燐粒子含有樹脂組成物にある。
【００２５】
本発明で用いる赤燐粒子には特に制限はないが、水酸化アルミニウム，水酸化マグネシウム，酸化チタン等の無機物、フェノール樹脂等の有機物によって分散，コーティングしたものを用いるのが好ましい。なお、その粒径は形成する絶縁膜の厚さより十分小さければ特に制限はなく、一般に平均粒径が２〜２０μｍの範囲のものが好ましい。
【００２６】
また、その添加量は、樹脂組成物中の樹脂成分の総量を１００重量部とし、２〜２０重量部が望ましい。この範囲であれば十分な難燃性を得ることができる。
【００２７】
また、上記範囲より少ないと十分な難燃性を得ることができない場合があり、上記範囲を超えると誘電特性が低下する場合がある。
【００２８】
本発明では、難燃助剤として芳香族含窒素化合物を添加することによって、赤燐の添加率を低減することができる。芳香族含窒素化合物としては、各種イミド化合物，芳香族アミン，ビスフェノールＡ型またはノボラック型シアネートエステル等が挙げられるが、窒素含有率の高いトリアジン骨格を有する化合物を添加することが好ましい。
【００２９】
トリアジン骨格を有する化合物の例としてはメラミン，トリアリル−１,３,５−トリアジン−２,４,６（１Ｈ，３Ｈ，５Ｈ）−トリオン、２,４,６−トリアリロキシ−１,３,５−トリアジン、２,４,６−トリ（２−ピリジル）−１,３,５−トリアジン、３,５,７−トリアミノ−Ｓ−トリアゾロ（４,３−Ａ）−Ｓ−トリアジン等が挙げられる。
【００３０】
その添加量は１〜１０重量部の範囲が好ましい。本添加量未満では難燃性の向上が認められない場合があり、逆に添加量がこれを超えると誘電特性が低下する場合がある。
【００３１】
本発明の樹脂組成物では、更に、高分子量体を添加することによって樹脂組成物に成膜性，強度，伸び，接着性を付与することができる。該高分子量体としてはブタジエン，イソプレン，スチレン，メチルスチレン，エチルスチレン，ジビニルベンゼン，アクリル酸エステル，アクリロニトリル，Ｎ−フェニルマレイミドおよびＮ−ビニルフェニルマレイミドの少なくとも一種からなる重合体，置換基を有していてもよいポリフェニレンオキサイド、並びに、脂環式構造を有するポリオレフィン等が挙げられる。
【００３２】
高分子量体の添加量には特に制限はないが、架橋成分が５〜９５重量部、高分子量体が９５〜５重量部の範囲が好ましい。前記範囲内で強度，伸び，接着力の向上等その目的に応じて組成を調整できる。特に、好ましい範囲としては架橋成分が５０〜８０重量部、高分子量体が５０〜２０重量部の範囲であり、これにより高分子量体が架橋性の官能基を有していない場合にも耐溶剤性が保たれる。
【００３３】
更に、本発明の樹脂組成物にはスチレン基を重合し得る硬化触媒またはスチレン基の重合を抑制し得る重合禁止剤を添加することによって熱硬化効率の向上、保存安定性の向上を図ることができる。
【００３４】
本発明に用いられる多官能スチレン化合物は、硬化触媒を添加しなくとも硬化することができるが、硬化触媒を添加することによって、多官能スチレン化合物の硬化を促進することができ、これにより低温での硬化が可能となる。その添加量は誘電率，誘電正接に影響を与えない範囲に設定することが好ましく、樹脂組成物中の樹脂成分の総量を１００重量部とすると、０.０００５〜１０重量部とすることが望ましい。
【００３５】
スチレン基の重合を開始し得るカチオンまたはラジカル活性種を、熱または光によって生成する硬化触媒を以下に示す。
【００３６】
カチオン重合開始剤としてはＢＦ₄，ＰＦ₆，ＡｓＦ₆，ＳｂＦ₆を対アニオンとするジアリルヨードニウム塩，トリアリルスルホニウム塩および脂肪族スルホニウム塩が挙げられる。これらの市販品には、旭電化工業製ＳＰ−７０，１７２，ＣＰ−６６，日本曹達製ＣＩ−２８５５，２８２３，三新化学工業製ＳＩ−１００ＬおよびＳＩ−１５０Ｌ等を使用することができる。
【００３７】
ラジカル重合開始剤としては、ベンゾインおよびベンゾインメチルのようなベンゾイン系化合物，アセトフェノンおよび２,２−ジメトキシ−２−フェニルアセトフェノンのようなアセトフェノン系化合物，チオキサントンおよび２,４−ジエチルチオキサントンのようなチオキサンソン系化合物，４,４'−ジアジドカルコン，２,６−ビス（４'−アジドベンザル）シクロヘキサノンおよび４,４'−ジアジドベンゾフェノンのようなビスアジド化合物，アゾビスイソブチルニトリル，２，２−アゾビスプロパン，ｍ,ｍ'−アゾキシスチレンおよびヒドラゾンのようなアゾ化合物、並びに２,５−ジメチル−２,５−ジ（ｔ−ブチルパーオキシ）ヘキサンおよび２,５−ジメチル−２,５−ジ（ｔ−ブチルパーオキシ）ヘキシン−３、ジクミルパーオキシドのような有機過酸化物等が挙げられる。
【００３８】
特に、官能基を持たない化合物の水素引き抜きを生じさせ、架橋成分と高分子量体間の架橋をもたらし得る有機過酸化物、または、ビスアジド化合物を添加することが望ましい。
【００３９】
重合禁止剤は、本発明の樹脂組成物の保存安定性を増す作用がある。その添加量は誘電特性，硬化時の反応性を著しく阻害しないような範囲が好ましく、樹脂組成物中の樹脂成分の合計１００重量部に対して、０.０００５〜５重量部が望ましい。重合禁止剤を前記範囲で添加すると、保存時の余計な架橋反応を抑制することができ、また、硬化時に著しい硬化障害をもたらすこともない。
【００４０】
重合禁止剤としてはハイドロキノン，ｐ−ベンゾキノン，クロラニル，トリメチルキノン，４−ｔ−ブチルピロカテコール等のキノン類および芳香族ジオール類が挙げられる。
【００４１】
本発明の樹脂組成物は、有機または無機のクロスまたは不織布に含浸し、乾燥させることによりプリプレグとして用いることができる。プリプレグの基材については特に制限はなく、各種ガラスクロス，ガラス不織布，アラミド不織布または多孔質ＰＴＦＥフィルム等を用いることができる。
【００４２】
プリプレグは、樹脂組成物のワニスに、基材となるクロスまたは不織布を浸し、これを乾燥することにより作製される。ワニス含浸後の乾燥条件は、樹脂組成にもよるが、例えば、溶媒としてトルエンを使用した場合、８０〜１３０℃で３０〜９０分程度乾燥するのが好ましい。
【００４３】
本発明のプリプレグに電解銅箔等の導体箔を重ね、加熱プレス加工することによって、表面に導体層を有する積層板を作製することができる。銅箔の厚さは、１２〜３６μｍ程度が好ましい。加熱プレス加工の条件は、樹脂組成にもよるが、例えば、高分子量体としてポリフェニレンエーテルを使用した場合、１５０〜２４０℃、１.０〜５ＭＰａで１〜３時間成形するのが好ましい。
【００４４】
こうして得られた積層板の導体層（銅箔）を、通常のエッチング法によって加工し、これを前記プリプレグを介して複数積層し、加熱プレス加工することによって多層プリント基板を作製することもできる。このようにして得られた多層プリント基板は誘電率，誘電正接が低く、優れた難燃性を有する。即ち、伝送特性と安全性が優れた多層プリント基板となる。
【００４５】
【発明の実施の形態】
以下に実施例および比較例を示して本発明を具体的に説明する。なお、以下の説明中に部とあるのは、特に断りのない限り重量部を指す。
【００４６】
表１，２に本発明の実施例と比較例での組成およびその特性を示す。また、実施例および比較例に使用した試薬の名称，合成方法，ワニスの調製法，硬化物の評価方法を次ぎに説明する。
【００４７】
（１） １,２−ビス（ビニルフェニル）エタン（ＢＶＰＥ）の合成
ＢＶＰＥは、以下に示すような公知の方法で合成した。５００ｍｌの三つ口フラスコにグリニャール反応用粒状マグネシウム（関東化学製）５.３６ｇ（２２０ｍｍｏｌ）を採り、滴下ロート，窒素導入管およびセプタムキャップを取り付けた。
【００４８】
窒素気流下、スターラーによってマグネシウム粒を攪拌しながら、系全体をドライヤーで加熱脱水した。乾燥テトラヒドロフラン３００ｍｌをシリンジにとり、セプタムキャップを通じて注入した。次ぎに、該溶液を−５℃に冷却後、滴下ロートを用いてビニルベンジルクロライド（ＶＢＣ：東京化成製）３０.５ｇ（２００ｍｍｏｌ）を約４時間かけて滴下した。
【００４９】
滴下終了後、０℃，２０時間攪拌を続けた。反応終了後、反応溶液をろ過して残存マグネシウムを除き、エバポレータで濃縮した。
【００５０】
濃縮溶液をヘキサンで希釈し、３.６％塩酸水溶液で１回、純水で３回洗浄し、次いで硫酸マグネシウムで脱水した。脱水溶液をシリカゲル（和光純薬製ワコーゲルＣ３００）／ヘキサンのショートカラムに通して精製し、真空乾燥してＢＶＰＥを得た。
【００５１】
得られたＢＶＰＥはｍ−ｍ体（液状），ｍ−ｐ体（液状），ｐ−ｐ体（結晶）の混合物であり、収率は９０％であった。¹Ｈ−ＮＭＲによってその構造を調べたところ、その値は文献値と一致した（６Ｈ−ビニル：α−２Ｈ、６.７ｐｐｍ、β−４Ｈ、５.７〜５.２ｐｐｍ；８Ｈ−アロマティック：７.１〜７.３５ｐｐｍ；４Ｈ−メチレン：２.９ｐｐｍ）。このＢＶＰＥを架橋成分として用いた。
【００５２】
（２） その他の試薬
高分子量体：ポリ−２,６−ジメチル−１,４−フェニレンオキシド（アルドリッチ製：ＰＰＥ）
難燃剤：赤燐粒子（日本化学工業製：ヒシガードＴＰ-Ａ１０）、平均粒径２０μｍ
難燃助剤：メラミン（和光純薬製）
（３） ワニスの調製法
所定量の高分子量体，架橋成分，赤燐粒子，メラミン，クロロホルムをボールミルにて約８時間攪拌して溶解，分散することによって樹脂組成物のワニスを作製した。
【００５３】
（４） 樹脂板の作製
前記ワニスをＰＥＴフィルムに塗布して乾燥後、これを剥離してポリテトラフルオロエチレン製のスペーサ内に所定量入れ、ポリイミドフィルムおよび鏡板を介し、真空下で加熱および加圧して硬化物の樹脂板を得た。加熱条件は１２０℃／３０分，１５０℃／３０分，２４０℃／１００分で、プレス圧力１.５ＭＰａの多段階加熱とした。樹脂板の大きさは７０ｍｍ×７０ｍｍ×１.５ｍｍとした。
【００５４】
（５） プリプレグの作製
プリプレグは、前記ワニスをガラスクロス（日東紡製＃２１１６）に含浸し、室温にて約１時間、９０℃で６０分間乾燥することにより作製した。
【００５５】
（６） プリプレグ硬化物の作製
積層板とした際の特性を知るため、前記方法で作製したプリプレグを１０枚重ねて真空下、加熱および加圧して模擬基板を作製した。加熱条件は１２０℃／３０分，１５０℃／３０分，２４０℃／１００分、プレス圧力１.５ＭＰａの多段階加熱とした。模擬基板は７０ｍｍ×７０ｍｍ×１.５ｍｍとした。
【００５６】
（７） 誘電率および誘電正接の測定
誘電率，誘電正接は空胴共振器摂動法（アジレントテクノロジー製８７２２ＥＳ型ネットワークアナライザー、関東電子応用開発製空胴共振器）によって、１０ＧＨｚでの値を測定した。
【００５７】
（８） 難燃性
難燃性はサンプルサイズ７０ｍｍ×３ｍｍ×１.５ｍｍの試料を用いてＵＬ−９４規格に基づき実施し、平均燃焼時間と最大燃焼時間を測定した。
【００５８】
〔比較例１〕
比較例１は、赤燐を添加していない樹脂組成物から作製した樹脂板である。誘電特性は優れているものの、難燃剤を含んでいないために難燃性が得られなかった。
【００５９】
〔実施例１〜４〕
実施例１〜４は、所定の樹脂組成物に種々の配合比で赤燐粒子を添加した例である。赤燐粒子を添加したことによって、比較例１に比べて燃焼時間が短くなることが分かった。この時、赤燐粒子の増加に伴い誘電率は２.５から２.８に増加するものの、誘電正接の値はいずれも０.００１５で殆ど変化しなかった。これにより優れた誘電特性を有する難燃性樹脂組成物が得られた。
【００６０】
【表１】

〔実施例５〜７〕
実施例５〜７は、実施例１の樹脂組成物にメラミンを添加量を変えて添加した樹脂組成物から作製した樹脂板である。メラミンを添加することにより難燃性が向上することが確認された。この時、誘電率は２.５１から２.６３に増加するものの、誘電正接は０.００１５から０.００１３に低下した。これにより、優れた誘電特性を有する難燃性樹脂組成物が得られた。
【００６１】
【表２】

〔実施例８〕
実施例２のワニスを用いてプリプレグを作製した。作製したプリプレグはタックフリー性を有していた。該プリプレグを１０枚重ね合わせて真空下、加熱，加圧してプリプレグ硬化物を作製した。該プリプレグ硬化物の樹脂含有量は３５ｗｔ％であった。これをＵＬ−９４規格に基づき難燃性試験を実施したところ、平均燃焼時間は０.４秒、最大燃焼時間は０.５秒で、Ｖ−０相当の難燃性を達成した。なお、誘電率は３.１２、誘電正接は０.００３５であった。
【００６２】
該プリプレグに用いた樹脂組成物は、優れた溶融流動性を有しており、多層プリント基板の層間接着剤として好適に用いることができる。
【００６３】
〔実施例９〕
実施例８で作製したプリプレグの両面に電解銅箔の粗面を張り付け、真空下、加圧，加熱して両面銅張積層板を作製した。加熱条件は１２０℃／３０分，１５０℃／３０分，２４０℃／１００分でプレス圧力１.５ＭＰａとした。銅箔とプリプレグは良好な接着性を示した。これにより低誘電損失な多層プリント基板の作製が可能となった。
【００６４】
〔実施例１０〕
図１は、本発明の多層プリント基板の作成工程の一例を示す模式断面図である。
【００６５】
（Ａ）では、実施例９で得た両面銅張積層板の片面にフォトレジスト３（日立化成工業製 ＨＳ４２５）をラミネートして全面に露光した。次いで、フォトレジスト３の無い面にフォトレジスト３（ＨＳ４２５）をラミネートしてテストパターンを露光し、未露光部分のフォトレジストを１％炭酸ナトリウム液で現像した。
【００６６】
（Ｂ）では、硫酸５％，過酸化水素５％のエッチング液で露出した銅箔をエッチング除去して、両面銅張積層板の片面に導体配線を形成した。
【００６７】
（Ｃ）では、３％水酸化ナトリウム溶液で残存するフォトレジスト３を除去し、片面に配線を有する配線基板を得た。同様にして２枚の配線基板を作製した。
【００６８】
（Ｄ）では、二枚の配線基板の配線側の面に実施例８のプリプレグ４を挟み、真空下、加熱，加圧して多層化した。加熱条件は１２０℃／３０分，１５０℃／３０分，２４０℃／１００分、プレス圧力１.５ＭＰａの多段階加熱とした。
【００６９】
（Ｅ）では、作製した多層板の両面の外装銅にフォトレジスト３（ＨＳ４２５）をラミネートしてテストパターンを露光し、未露光部分のフォトレジストを１％炭酸ナトリウム液で現像した。
【００７０】
（Ｆ）では、硫酸５％、過酸化水素５％のエッチング液で露出した銅箔をエッチング除去し、３％水酸化ナトリウム溶液で残存するフォトレジストを除去して外装配線６を形成した。
【００７１】
（Ｇ）では、内層配線５と外装配線６を接続するスルーホール７をドリル加工で形成した。
【００７２】
（Ｈ）では、配線基板をめっき触媒のコロイド溶液に浸して、スルーホール7内と基板表面に触媒８を付与した。
【００７３】
（Ｉ）では、めっき触媒の活性化処理の後、無電解めっき液（日立化成工業製ＣＵＳＴ２０００）により約１μｍの種膜９を形成した。
【００７４】
（Ｊ）では、フォトレジスト（日立化成工業製 ＨＮ９２０）を配線基板の両面にラミネートした。
【００７５】
（Ｋ）では、スルーホール7部分および配線基板の端部をマスクして露光後、３％炭酸ナトリウムで現像して開孔部１０を設けた。
【００７６】
（Ｌ）では、配線基板の端部に電極１１を設け、電解めっきによってスルーホール7部分にめっき銅を約１８μｍ形成した。
【００７７】
（Ｍ）では、電極１１部分を切断除去し、残存するフォトレジストを５％水酸化ナトリウム水溶液で除去した。
【００７８】
（Ｎ）では、硫酸５％，過酸化水素５％のエッチング液に配線基板を浸し、約１μｍエッチングして種膜９を除去し多層配線板を作製した。得られた多層配線板は低誘電率，低誘電正接で、かつ、高い難燃性を示した。
【００７９】
【発明の効果】
本発明によれば、誘電率、誘電正接が低く、難燃性の硬化物を与える樹脂組成物が得られる。本樹脂組成物は、高周波用電気部品の絶縁材料に好適であり、高周波信号用多層プリント基板およびそれに用いるプリプレグ，積層板へ応用することで、低誘電損失と難燃性を両立できると云う効果が得られる。
【図面の簡単な説明】
【図１】多層配線板作製時の製造工程の一例を示す模式断面図である。
【符号の説明】
１…樹脂基板、２…電解銅箔、３…フォトレジスト、４…プリプレグ、５…内層配線、６…外層配線、７…スルーホール、８…めっき触媒、９…種膜、１０…開孔部、１１…電極、１２…めっき銅。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resin composition having a low dielectric loss and a flame retardancy to cope with a high-frequency signal, a prepreg using the resin composition, a laminate with a conductor layer, and a multilayer printed board.
[0002]
[Prior art]
In recent years, the signal band of information communication devices such as PHS and mobile phones, and the CPU clock time of computers have reached the GHz band, and the frequency has been increasing.
[0003]
The dielectric loss of an electrical signal is proportional to the product of the square root of the dielectric constant of the insulator forming the circuit, the dielectric loss tangent and the frequency of the signal used. Therefore, the higher the frequency of the signal used, the greater the dielectric loss.
[0004]
Since the dielectric loss attenuates the electrical signal and impairs the reliability of the signal, it is necessary to select a material having a small dielectric constant and dielectric loss tangent for the insulator in order to suppress this.
[0005]
Removal of polar groups in the molecular structure is effective in reducing dielectric constant and dielectric loss tangent of insulators, such as fluorine resin, curable polyolefin, cyanate ester resin, curable polyphenylene oxide, allyl-modified polyphenylene ether, A polyetherimide modified with divinylbenzene or divinylnaphthalene has been proposed.
[0006]
For example, a fluororesin represented by polytetrafluoroethylene (PTFE) has a low dielectric constant and dielectric loss tangent, and is used as a substrate material that handles high-frequency signals.
[0007]
On the other hand, various non-fluorine type low dielectric constant and low dielectric loss tangent resins that are soluble in organic solvents and easy to handle have been studied. For example, there is an example in which a glass cloth is impregnated with a diene polymer such as polybutadiene described in JP-A-8-208856 and cured with a peroxide.
[0008]
There is an example of a cyclic polyolefin obtained by introducing an epoxy group into a norbornene-based addition polymer described in JP-A-10-158337 and imparting curability.
[0009]
There is an example in which the cyanate ester, diene polymer and epoxy resin described in JP-A-11-124491 are heated to form a B stage.
[0010]
There is an example of a modified resin comprising polyphenylene oxide, a diene polymer, and triallyl isocyanate described in JP-A-9-118759.
[0011]
There is an example of a resin composition composed of allylated polyphenylene ether and triallyl isocyanate described in JP-A-9-246429.
[0012]
There is an example in which polyetherimide described in JP-A-5-156159 is alloyed with styrene, divinylbenzene or divinylnaphthalene.
[0013]
In addition, there are many examples of resin compositions composed of, for example, hydroquinone bis (vinylbenzyl) ether and a novolak phenol resin synthesized by a Williamson reaction from a dihydroxy compound described in JP-A-5-78552 and chloromethylstyrene. .
[0014]
On the other hand, the above-mentioned insulating material must be flame retardant from the viewpoint of the safety of the applied product. Conventionally, the addition of flame retardants such as red phosphorus, phosphoric acid esters, nitrogen-containing compounds, halides, metal hydrates, and metal oxides has been studied. For example, examples described in JP-A-4-117442 using a compound of nitrogen compound such as melamine, polyol and organophosphate, examples described in JP-A-9-104421 using metal oxides, metal There is an example using a hydrate and potassium titanate, and an example of JP 2000-26553 A using a phosphorus compound and a nitrogen-containing compound.
[0015]
Further, there are many examples such as Japanese Patent Application Laid-Open No. 2000-106041 using red phosphorus and metal hydrate, and Japanese Patent Application Laid-Open No. 6-106676 using halide.
[0016]
[Problems to be solved by the invention]
Even in the case of a material that has been made flame retardant by using a material having a low dielectric constant and a low dielectric loss tangent as described above, it is not sufficient in terms of dielectric characteristics to be compatible with future high frequency equipment.
[0017]
An object of the present invention is to provide a low dielectric loss tangent resin composition containing a polyfunctional styrene compound having excellent dielectric properties as compared with conventional materials.
[0018]
Another object of the present invention is to provide a resin composition containing red phosphorus particles that is flame retardant without impairing the low dielectric constant and low dielectric loss tangent of the low dielectric loss tangent resin composition. . Another object of the present invention is to provide a prepreg, a laminate and a multilayer printed board using the resin composition.
[0019]
[Means for Solving the Problems]
The cured product of the polyfunctional styrene compound has a low dielectric constant and a low dielectric loss tangent, and the values thereof are a dielectric constant of about 2.5 and a dielectric loss tangent of less than 0.002 at a measurement frequency of 10 GHz.
[0020]
As a result of various investigations of flame retardants that impart flame retardancy to the cured resin composition without impairing this property, the addition of red phosphorus particles, which are inorganic compounds, increases the dielectric loss tangent. It was found that high flame retardancy can be obtained while suppressing the above. In addition, red phosphorus particles have a high flame retardant effect, so the amount added is small and has little influence on the dielectric constant.
[0021]
Furthermore, the addition amount of red phosphorus particles can be further reduced by adding an aromatic nitrogen-containing compound. Moreover, the resin composition of this invention can be processed into a prepreg, a laminated board, and a multilayer printed circuit board.
[0022]
The resin composition of the present invention and the cured product thereof will be described.
[0023]
The resin composition of the present invention has the formula 1
[0024]
[Chemical formula 2]

(Wherein R represents a hydrocarbon skeleton which may have a substituent, R ² , R ³ and R ⁴ each represent a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms which may be different from each other; ⁵ , R ⁶ , R ⁷ , and R ⁸ each have a polyfunctional styrene group represented by a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and n represents an integer of 2 or more. The red phosphorus particle-containing resin composition contains a crosslinking component having a weight average molecular weight of 1000 or less and contains red phosphorus particles.
[0025]
The red phosphorus particles used in the present invention are not particularly limited, but it is preferable to use particles dispersed and coated with an inorganic substance such as aluminum hydroxide, magnesium hydroxide or titanium oxide, or an organic substance such as a phenol resin. The particle diameter is not particularly limited as long as it is sufficiently smaller than the thickness of the insulating film to be formed. In general, the average particle diameter is preferably in the range of 2 to 20 μm.
[0026]
Further, the added amount is preferably 2 to 20 parts by weight, with the total amount of resin components in the resin composition being 100 parts by weight. If it is this range, sufficient flame retardance can be obtained.
[0027]
Moreover, if it is less than the said range, sufficient flame retardance may not be acquired, and when it exceeds the said range, a dielectric characteristic may fall.
[0028]
In the present invention, the addition rate of red phosphorus can be reduced by adding an aromatic nitrogen-containing compound as a flame retardant aid. Examples of the aromatic nitrogen-containing compound include various imide compounds, aromatic amines, bisphenol A type or novolac type cyanate esters, and it is preferable to add a compound having a triazine skeleton having a high nitrogen content.
[0029]
Examples of the compound having a triazine skeleton include melamine, triallyl-1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,4,6-triaryloxy-1,3,5- And triazine, 2,4,6-tri (2-pyridyl) -1,3,5-triazine, 3,5,7-triamino-S-triazolo (4,3-A) -S-triazine, and the like.
[0030]
The addition amount is preferably in the range of 1 to 10 parts by weight. If the addition amount is less than this amount, the flame retardancy may not be improved. Conversely, if the addition amount exceeds this amount, the dielectric properties may be deteriorated.
[0031]
In the resin composition of the present invention, film forming properties, strength, elongation and adhesion can be imparted to the resin composition by further adding a high molecular weight substance. The high molecular weight polymer has a butadiene, isoprene, styrene, methyl styrene, ethyl styrene, divinyl benzene, acrylic ester, acrylonitrile, a polymer composed of at least one of N-phenyl maleimide and N-vinyl phenyl maleimide, and a substituent. Examples thereof include polyphenylene oxide which may be present, and polyolefin having an alicyclic structure.
[0032]
Although there is no restriction | limiting in particular in the addition amount of a high molecular weight body, The cross-linking component is 5 to 95 parts by weight, and the high molecular weight body is preferably in the range of 95 to 5 parts by weight. Within the above range, the composition can be adjusted according to the purpose such as improvement of strength, elongation and adhesion. In particular, the preferred range is 50 to 80 parts by weight of the crosslinking component and 50 to 20 parts by weight of the high molecular weight compound, which makes the solvent resistant even when the high molecular weight product does not have a crosslinkable functional group. Sex is maintained.
[0033]
Furthermore, by adding a curing catalyst capable of polymerizing styrene groups or a polymerization inhibitor capable of inhibiting the polymerization of styrene groups to the resin composition of the present invention, it is possible to improve thermosetting efficiency and storage stability. it can.
[0034]
The polyfunctional styrene compound used in the present invention can be cured without the addition of a curing catalyst, but by adding a curing catalyst, the curing of the polyfunctional styrene compound can be promoted, thereby reducing the temperature. Can be cured. The addition amount is preferably set in a range that does not affect the dielectric constant and dielectric loss tangent. When the total amount of the resin components in the resin composition is 100 parts by weight, it is preferably 0.0005 to 10 parts by weight. .
[0035]
Curing catalysts that generate cation or radical active species capable of initiating polymerization of styrene groups by heat or light are shown below.
[0036]
Examples of the cationic polymerization initiator include diallyl iodonium salts, triallyl sulfonium salts, and aliphatic sulfonium salts having BF ₄ , PF ₆ , AsF ₆ , and SbF ₆ as counter anions. As these commercial products, SP-70, 172, CP-66 manufactured by Asahi Denka Kogyo, CI-2855, 2823 manufactured by Nippon Soda, SI-100L and SI-150L manufactured by Sanshin Chemical Industry, and the like can be used.
[0037]
Radical polymerization initiators include benzoin compounds such as benzoin and benzoin methyl, acetophenone compounds such as acetophenone and 2,2-dimethoxy-2-phenylacetophenone, thioxanthone compounds such as thioxanthone and 2,4-diethylthioxanthone Compounds, bisazide compounds such as 4,4′-diazidochalcone, 2,6-bis (4′-azidobenzal) cyclohexanone and 4,4′-diazidobenzophenone, azobisisobutylnitrile, 2,2-azobispropane , M, m'-azoxystyrene and hydrazones, and 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and 2,5-dimethyl-2,5-di ( t-butylperoxy) hexyne-3, dicumylperoxy Organic peroxides, and the like, such as.
[0038]
In particular, it is desirable to add an organic peroxide or a bisazide compound capable of causing hydrogen abstraction of a compound having no functional group and causing crosslinking between the crosslinking component and the high molecular weight product.
[0039]
The polymerization inhibitor has an action of increasing the storage stability of the resin composition of the present invention. The addition amount is preferably in a range that does not significantly impair the dielectric properties and reactivity during curing, and is preferably 0.0005 to 5 parts by weight with respect to 100 parts by weight of the total resin components in the resin composition. When the polymerization inhibitor is added within the above range, an excessive crosslinking reaction during storage can be suppressed, and no significant curing failure is caused during curing.
[0040]
Examples of the polymerization inhibitor include quinones such as hydroquinone, p-benzoquinone, chloranil, trimethylquinone, 4-t-butylpyrocatechol, and aromatic diols.
[0041]
The resin composition of the present invention can be used as a prepreg by impregnating an organic or inorganic cloth or nonwoven fabric and drying it. There is no restriction | limiting in particular about the base material of a prepreg, Various glass cloth, a glass nonwoven fabric, an aramid nonwoven fabric, a porous PTFE film, etc. can be used.
[0042]
The prepreg is produced by immersing a cloth or non-woven fabric serving as a base material in a varnish of the resin composition and drying the cloth. Although the drying conditions after varnish impregnation depend on the resin composition, for example, when toluene is used as a solvent, it is preferably dried at 80 to 130 ° C. for about 30 to 90 minutes.
[0043]
By laminating a conductive foil such as an electrolytic copper foil on the prepreg of the present invention and subjecting it to hot pressing, a laminate having a conductive layer on the surface can be produced. The thickness of the copper foil is preferably about 12 to 36 μm. The conditions for the hot press processing depend on the resin composition, but for example, when polyphenylene ether is used as the high molecular weight material, it is preferably molded at 150 to 240 ° C. and 1.0 to 5 MPa for 1 to 3 hours.
[0044]
A multilayer printed circuit board can also be produced by processing the conductor layer (copper foil) of the laminated board obtained in this way by a normal etching method, laminating a plurality of these via the prepreg, and performing hot press processing. The multilayer printed circuit board thus obtained has a low dielectric constant and dielectric loss tangent and has excellent flame retardancy. That is, the multilayer printed circuit board has excellent transmission characteristics and safety.
[0045]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be specifically described below with reference to examples and comparative examples. In the following description, “parts” refers to parts by weight unless otherwise specified.
[0046]
Tables 1 and 2 show the compositions and characteristics of Examples and Comparative Examples of the present invention. The names of the reagents used in the examples and comparative examples, synthesis methods, varnish preparation methods, and cured product evaluation methods will be described below.
[0047]
(1) Synthesis of 1,2-bis (vinylphenyl) ethane (BVPE) BVPE was synthesized by a known method as shown below. In a 500 ml three-necked flask, 5.36 g (220 mmol) of granular magnesium for Grignard reaction (manufactured by Kanto Chemical) was taken, and a dropping funnel, a nitrogen introducing tube and a septum cap were attached.
[0048]
The whole system was heated and dehydrated with a dryer while stirring the magnesium particles with a stirrer under a nitrogen stream. 300 ml of dry tetrahydrofuran was taken into a syringe and injected through a septum cap. Next, after cooling the solution to −5 ° C., 30.5 g (200 mmol) of vinylbenzyl chloride (VBC: manufactured by Tokyo Chemical Industry Co., Ltd.) was dropped over about 4 hours using a dropping funnel.
[0049]
After completion of dropping, stirring was continued at 0 ° C. for 20 hours. After completion of the reaction, the reaction solution was filtered to remove residual magnesium and concentrated with an evaporator.
[0050]
The concentrated solution was diluted with hexane, washed once with 3.6% hydrochloric acid aqueous solution and three times with pure water, and then dehydrated with magnesium sulfate. The dewatered aqueous solution was purified by passing through a short column of silica gel (Wakogel C300 manufactured by Wako Pure Chemical Industries) / hexane and vacuum dried to obtain BVPE.
[0051]
The obtained BVPE was a mixture of mm body (liquid), mp body (liquid), and pp body (crystal), and the yield was 90%. ^When the structure was examined by ¹ H-NMR, the value was consistent with the literature value (6H-vinyl: α-2H, 6.7 ppm, β-4H, 5.7 to 5.2 ppm; 8H-aromatic: 7.1-7.35 ppm; 4H-methylene: 2.9 ppm). This BVPE was used as a crosslinking component.
[0052]
(2) Other reagent high molecular weight: poly-2,6-dimethyl-1,4-phenylene oxide (manufactured by Aldrich: PPE)
Flame retardant: Red phosphorus particles (manufactured by Nippon Chemical Industry: Hishiguard TP-A10), average particle size 20 μm
Flame retardant aid: Melamine (Wako Pure Chemical Industries)
(3) Preparation of varnish A varnish of a resin composition was prepared by stirring and dissolving a predetermined amount of a high molecular weight substance, a crosslinking component, red phosphorus particles, melamine, and chloroform in a ball mill for about 8 hours.
[0053]
(4) Preparation of resin plate After applying the varnish to a PET film and drying it, it is peeled off and placed in a polytetrafluoroethylene spacer, and heated and heated under vacuum through a polyimide film and an end plate. To obtain a cured resin plate. The heating conditions were 120 ° C./30 minutes, 150 ° C./30 minutes, 240 ° C./100 minutes, and multi-stage heating with a press pressure of 1.5 MPa. The size of the resin plate was 70 mm × 70 mm × 1.5 mm.
[0054]
(5) Preparation of prepreg The prepreg was prepared by impregnating the varnish into a glass cloth (Nittobo # 2116) and drying at room temperature for about 1 hour and at 90 ° C for 60 minutes.
[0055]
(6) Preparation of cured prepreg In order to know the characteristics when a laminated board was used, 10 prepregs prepared by the above method were stacked and heated and pressed under vacuum to prepare a simulated substrate. The heating conditions were multi-stage heating at 120 ° C./30 minutes, 150 ° C./30 minutes, 240 ° C./100 minutes, and a press pressure of 1.5 MPa. The simulated substrate was 70 mm × 70 mm × 1.5 mm.
[0056]
(7) Measurement of dielectric constant and dielectric loss tangent The dielectric constant and dielectric loss tangent were measured at 10 GHz by a cavity resonator perturbation method (Agilent Technologies 8722ES network analyzer, Kanto Electronics Application Development cavity resonator). .
[0057]
(8) Flame retardancy Flame retardancy was carried out based on the UL-94 standard using a sample size of 70 mm × 3 mm × 1.5 mm, and the average burning time and the maximum burning time were measured.
[0058]
[Comparative Example 1]
Comparative Example 1 is a resin plate made from a resin composition to which no red phosphorus is added. Although the dielectric properties were excellent, flame retardance was not obtained because it did not contain a flame retardant.
[0059]
[Examples 1 to 4]
Examples 1-4 are examples in which red phosphorus particles are added to various resin compositions at various blending ratios. It was found that the combustion time was shortened by adding red phosphorus particles as compared with Comparative Example 1. At this time, the dielectric constant increased from 2.5 to 2.8 with the increase of red phosphorus particles, but the value of dielectric loss tangent was 0.0015 and hardly changed. Thereby, a flame retardant resin composition having excellent dielectric properties was obtained.
[0060]
[Table 1]

[Examples 5 to 7]
Examples 5 to 7 are resin plates produced from resin compositions obtained by adding melamine to the resin composition of Example 1 while changing the addition amount. It was confirmed that the flame retardancy was improved by adding melamine. At this time, the dielectric constant increased from 2.51 to 2.63, but the dielectric loss tangent decreased from 0.0015 to 0.0001. Thereby, a flame retardant resin composition having excellent dielectric properties was obtained.
[0061]
[Table 2]

Example 8
A prepreg was prepared using the varnish of Example 2. The produced prepreg had tack-free properties. Ten prepregs were superposed and heated and pressurized under vacuum to produce a cured prepreg. The resin content of the prepreg cured product was 35 wt%. When this was subjected to a flame retardancy test based on the UL-94 standard, the average burning time was 0.4 seconds, the maximum burning time was 0.5 seconds, and flame retardancy equivalent to V-0 was achieved. The dielectric constant was 3.12. The dielectric loss tangent was 0.0033.
[0062]
The resin composition used for the prepreg has excellent melt fluidity, and can be suitably used as an interlayer adhesive for multilayer printed circuit boards.
[0063]
Example 9
The rough surface of the electrolytic copper foil was pasted on both sides of the prepreg produced in Example 8, and pressurized and heated under vacuum to produce a double-sided copper clad laminate. The heating conditions were 120 ° C./30 minutes, 150 ° C./30 minutes, 240 ° C./100 minutes and a press pressure of 1.5 MPa. The copper foil and prepreg showed good adhesion. This made it possible to produce a multilayer printed board with low dielectric loss.
[0064]
Example 10
FIG. 1 is a schematic cross-sectional view showing an example of a production process of a multilayer printed board according to the present invention.
[0065]
In (A), a photoresist 3 (HS425 manufactured by Hitachi Chemical Co., Ltd.) was laminated on one side of the double-sided copper clad laminate obtained in Example 9, and the entire surface was exposed. Next, a photoresist 3 (HS425) was laminated on the surface without the photoresist 3 to expose the test pattern, and the unexposed photoresist was developed with a 1% sodium carbonate solution.
[0066]
In (B), the copper foil exposed with an etching solution of 5% sulfuric acid and 5% hydrogen peroxide was removed by etching to form a conductor wiring on one side of the double-sided copper-clad laminate.
[0067]
In (C), the remaining photoresist 3 was removed with a 3% sodium hydroxide solution to obtain a wiring board having wiring on one side. Similarly, two wiring boards were produced.
[0068]
In (D), the prepreg 4 of Example 8 was sandwiched between the wiring-side surfaces of the two wiring boards, and multilayered by heating and pressing under vacuum. The heating conditions were multi-stage heating at 120 ° C./30 minutes, 150 ° C./30 minutes, 240 ° C./100 minutes, and a press pressure of 1.5 MPa.
[0069]
In (E), photoresist 3 (HS425) was laminated on the exterior copper on both sides of the produced multilayer board, the test pattern was exposed, and the unexposed photoresist was developed with 1% sodium carbonate solution.
[0070]
In (F), the exposed copper foil was removed by etching with an etching solution of 5% sulfuric acid and 5% hydrogen peroxide, and the remaining photoresist was removed with a 3% sodium hydroxide solution to form the exterior wiring 6.
[0071]
In (G), a through hole 7 for connecting the inner layer wiring 5 and the outer wiring 6 was formed by drilling.
[0072]
In (H), the wiring board was immersed in a colloidal solution of a plating catalyst, and the catalyst 8 was applied to the inside of the through hole 7 and the substrate surface.
[0073]
In (I), after activating the plating catalyst, a seed film 9 of about 1 μm was formed with an electroless plating solution (CUST2000 manufactured by Hitachi Chemical Co., Ltd.).
[0074]
In (J), a photoresist (HN920 manufactured by Hitachi Chemical Co., Ltd.) was laminated on both sides of the wiring board.
[0075]
In (K), the through-hole 7 portion and the end portion of the wiring substrate were masked and exposed, and then developed with 3% sodium carbonate to provide the opening 10.
[0076]
In (L), the electrode 11 was provided at the end of the wiring substrate, and plated copper was formed in the through hole 7 portion by about 18 μm by electrolytic plating.
[0077]
In (M), the electrode 11 portion was cut and removed, and the remaining photoresist was removed with a 5% aqueous sodium hydroxide solution.
[0078]
In (N), the wiring board was immersed in an etching solution of 5% sulfuric acid and 5% hydrogen peroxide, and the seed film 9 was removed by etching by about 1 μm to produce a multilayer wiring board. The obtained multilayer wiring board exhibited a low dielectric constant, a low dielectric loss tangent, and a high flame resistance.
[0079]
【The invention's effect】
According to the present invention, a resin composition having a low dielectric constant and dielectric loss tangent and giving a flame retardant cured product can be obtained. This resin composition is suitable as an insulating material for high-frequency electrical components, and can be applied to a multilayer printed board for high-frequency signals and prepregs and laminates used therefor to achieve both low dielectric loss and flame retardancy. Is obtained.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an example of a manufacturing process for producing a multilayer wiring board.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Resin substrate, 2 ... Electrolytic copper foil, 3 ... Photoresist, 4 ... Prepreg, 5 ... Inner layer wiring, 6 ... Outer layer wiring, 7 ... Through hole, 8 ... Plating catalyst, 9 ... Seed film, 10 ... Opening part , 11 ... electrode, 12 ... plated copper.

Claims (7)

1,2-bis as a (vinylphenyl) ethane crosslinking component comprises 50 to 95 parts by weight when the total amount of the resin component was 100 parts by weight, and poly-2,6-dimethyl-1 as a high polymer, A low dielectric loss tangent resin composition comprising 4-phenylene oxide and red phosphorus particles as a flame retardant. The low dielectric loss tangent resin composition according to claim 1, wherein the low dielectric loss tangent resin composition contains melamine. The low dielectric loss tangent resin composition according to claim 1 or 2, wherein the low dielectric loss tangent resin composition contains a curing catalyst capable of polymerizing styrene groups or a polymerization inhibitor capable of suppressing polymerization of styrene groups. The total amount of the resin component of the low dielectric loss tangent resin composition is 100 parts by weight, the addition amount of the red phosphorus particles is 2 to 20 parts by weight, the addition amount of melamine is 1 to 10 parts by weight, and the addition amount of the curing catalyst is 0. The low dielectric loss tangent resin composition according to claim 3, wherein the amount of addition of the polymerization inhibitor is 0.0005 to 5 parts by weight. A prepreg obtained by impregnating an organic or inorganic cloth or non-woven fabric with the low dielectric loss tangent resin composition according to any one of claims 1 to 4 and drying it. A laminated board, wherein a conductor layer is provided on at least one surface of the prepreg or cured product thereof according to claim 5. A multilayer printed circuit board comprising: a laminate layer bonded to a conductor layer of the laminate according to claim 6, the wiring laminate being laminated via a prepreg.

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