JP3656224B2

JP3656224B2 - Epoxy resin composition

Info

Publication number: JP3656224B2
Application number: JP30858996A
Authority: JP
Inventors: 千明浅野; 洋佐藤; 雅男軍司
Original assignee: Tohto Kasei Co Ltd
Current assignee: Tohto Kasei Co Ltd
Priority date: 1996-10-14
Filing date: 1996-10-14
Publication date: 2005-06-08
Anticipated expiration: 2016-10-14
Also published as: JPH10120875A

Description

【０００１】
【産業上の利用分野】
本発明は、内層回路への埋め込み性に優れ、回路基板との接着性及びラミネート後の外層回路の平滑性に優れたガラスクロスをほとんど用いず板厚を極薄にでき、耐熱性のある多層プリント配線板用エポキシ樹脂組成物に関するものである。
【０００２】
【従来の技術】
従来、多層プリント配線板は回路形成された内装回路基板上に、ガラスクロスにエポキシ樹脂を含浸させた後Ｂステージ化したプリプレグシートを重ね、さらにその上に銅箔を重ね加圧加熱一体成形を行うという製造方法をとっている。しかし、この方法ではガラスクロスにエポキシ樹脂を含浸させＢステージ化してプリプレグを作成するのにまず設備と時間がかかり、さらに多層化する為に銅箔を重ねて加圧加熱一体成形するのに設備と時間がかかるというように、膨大な設備と時間が掛かっており、高コストであった。又、ガラスクロスを用いる為に層間厚さを極薄化ができなかった。
【０００３】
【発明が解決しようとする課題】
本発明は従来の技術ではなし得なかった、多層プリント配線板の低コスト化、及び極薄化が可能で耐熱性のあるエポキシ樹脂組成物を提供することを目的とする。
【０００４】
【課題を解決する為の手段及び作用】
本発明は上記課題を解決したもので、（Ａ）成分が下記式１（化１）で表され、分子量範囲が１０，０００〜２００，０００（ゲルパーミエーションクロマトグラフィー測定、標準ポリスチレン換算による、重量平均分子量、以下分子量というのはこの測定法による重量平均分子量を言う）、ハロゲン含有量が５重量％〜４０重量％、酸価が３０ｍｇＫＯＨ／ｇ〜２５０ｍｇＫＯＨ／ｇのエポキシ樹脂−酸無水物付加物であり、（Ｂ）成分がエポキシ当量４５００ｇ／ｅｑ〜１００ｇ／ｅｑの芳香族系エポキシ樹脂、（Ｃ）成分が硬化促進剤から構成される組成物であって、場合によっては粘度調整の為の有機溶剤と有機、無機充填剤とを含有する熱硬化型絶縁層形成能を有するエポキシ樹脂組成物であり、（Ａ）成分の割合が（Ａ）＋（Ｂ）に対して７５重量％〜２０重量％であるエポキシ樹脂組成物、及びこのエポキシ樹脂組成物を銅箔に塗布してなるプリント配線板用接着剤付き銅箔である。そしてこの接着剤付き銅箔は内層回路基板にラミネート後熱硬化させることにより極薄の、低コストで耐熱性のある多層プリント配線板に用いられる。
【化１】
（式１中Ｒ^１、Ｒ^２は水素原子、炭素数１〜５のアルキル基、ハロゲン原子のいずれかであり、Ｘは−ＳＯ_２−、−ＣＨ_２−、−Ｃ（ＣＨ_３）_２−、−Ｏ−であり、ｌは０または１を表す。Ｒ^３は水素原子又は式２（化２）のいずれかであり、水素原子である割合が全Ｒ^３の８５％以下である。
【化２】
式２中Ｙは酸無水物残基を表し、ｍ＝１〜３の整数である。
Ｚは式３（化３）又は−Ｒ^３のいずれかを示す。
【化３】
）
【０００５】
本発明に於けるエポキシ樹脂組成物は当然のことながら、ガラスエポキシ回路基板と同等の耐熱性、難燃性、電気絶縁性等の様々な特性を満足し、且つ、銅箔に塗布した場合は、溶剤揮発後の銅箔カールや、裁断時の粉落ちが無いようにしなければならない。又、内層回路基板にラミネートした時は、内層回路埋め込み性がなければならない。
【０００６】
（Ａ）成分の分子量が１０，０００未満では、そのエポキシ樹脂組成物を、銅箔に塗布し乾燥した後の接着剤付き銅箔が、銅箔カールや裁断時の粉落ち等を起こし、不良品となる。又、分子量が２００，０００を越えると、溶剤で希釈溶解しても、通常の溶媒量である７０重量％〜４０重量％では、溶液粘度が高すぎ、銅箔に塗布することが困難となる。銅箔に塗布可能な溶液粘度にするには、あまり好ましくない溶剤を大量に加えなければならず、不経済であり、環境に対しても良くない。尚、（Ａ）成分の分子量は好ましくは１５，０００〜１６０，０００、より好ましくは２０，０００〜１００，０００である。
【０００７】
（Ａ）成分のハロゲン含有量が５重量％未満では、本発明のエポキシ樹脂組成物に於いて、十分な難燃性を付与できず、又、４０重量％以下で十分に難燃性を付与できる為、４０重量％を越えるものは必要ではない。
【０００８】
（Ａ）成分の酸価が３０ｍｇＫＯＨ／ｇ未満では、硬化した時の架橋密度が低くなり希望する耐熱性が出ない。又、２５０ｍｇＫＯＨ／ｇを越えた樹脂を合成しようとした場合、２官能以上の酸無水物を大量に使用しなければならず、エポキシ樹脂−酸無水物（（Ａ）成分）の合成時に付加重合反応を起こし、ゲル化してしまい、合成が非常に困難である。
【０００９】
（Ａ）成分の樹脂を合成するには、酸無水物の分子量も考慮しなければならないが、比較的高分子量のエポキシ樹脂を用いなければならない。比較的高分子量のエポキシ樹脂はビスフェノールＡ（ＢＰＡ）又は／及びテトラブロムビスフェノールＡ（ＴＢＡ）とエピクロルヒドリンの直接反応によるか、ＢＰＡ又は／及びＴＢＡのジグリシジルエーテルとＢＰＡ又は／及びＴＢＡの付加重合による方法が知られているが、いずれの方法によるものであっても良い。又、前記高分子のエポキシ樹脂の両末端がエポキシ基（この場合式１の末端基は式３で表される基となる）であるか、又は末端基の一部又は全部がフェノール性水酸基（この場合式１の末端基はＲ^３となる）となっている変性高分子エポキシ樹脂であっても良い。
【００１０】
又、エポキシ樹脂組成物の（Ａ）成分と（Ｂ）成分の配合比率は（Ａ）成分のカルボン酸基と（Ｂ）成分のエポキシ基の当量比で１：１が一番好ましく、（Ａ）＋（Ｂ）成分中の（Ａ）成分の割合が７５重量％を越える場合は、通常の溶剤量である７０重量％〜４０重量％では溶液粘度が高すぎ、あまり好ましくない溶剤を多量に加えなければならず不経済であり、環境にも良くない。又、２０重量％を下回る場合は、硬化した時の耐熱性が不足し、且つ、接着剤付き銅箔の塗膜性能が悪化し、銅箔カールや裁断時の粉落ち等の現象を生じる事になる。具体的には、酸無水物付加用エポキシ樹脂としては、ビスフェノールＡ型、Ｆ型、Ｓ型等の単一またはそれぞれの共縮合型エポキシ樹脂で、難燃性を持たす為にそれぞれの一部又は、全てがハロゲン化されたものが用いられる。
【００１１】
酸無水物としては、無水マレイン酸、無水コハク酸、無水フタル酸、無水テトラヒドロフタル酸、無水ヘキサヒドロフタル酸、メチルテトラヒドロ無水フタル酸、無水ピロメリット酸、ベンゾフェノンテトラカルボン酸二無水物、ビフェニルテトラカルボン酸二無水物、ビフェニルエーテルテトラカルボン酸二無水物等が用いられる。
【００１２】
エポキシ樹脂と酸無水物の反応は不活性な溶媒、例えばキシレン、トルエン、メチルエチルケトン、ジエチルセロソルブ、メチルセロソルブアセテート、メチルエチルカルビトール等を単独に又は混合したものにエポキシ樹脂を溶かし、酸無水物を一括、又は、分割して加えて反応させる。この時、触媒を加える場合はエポキシの合成に使用される一般的な触媒で良く、イミダゾール、トリフェニールフォスフィン、フォスフォニウム塩等の触媒が用いられる。又、反応温度は９０℃〜１５０℃、好ましくは１１５℃〜１２５℃である。
【００１３】
この様にして合成されたエポキシ樹脂−酸無水物付加物（（Ａ）成分）はそれのみで、成型時の樹脂流れが少なく、回路埋め込み性が良く、可とう性、難燃性のある物質であるが、耐熱性がやや不足する。従って、耐熱性を持たす為に、さらにエポキシ樹脂を加えて加熱硬化させることが必要である。
【００１４】
（Ｂ）成分であるエポキシ樹脂としては、硬化後の可とう性等の物性を落とさず耐熱性を上げるもので、芳香族系で且つエポキシ当量が４５００ｇ／ｅｑ〜１００ｇ／ｅｑのものが良い。エポキシ当量が４５００ｇ／ｅｑを越えると、加えるエポキシ樹脂の量が多くなり、エポキシ樹脂−酸無水物付加物（（Ａ）成分）の物性を損なう事になり、且つ、架橋密度が低くなり望ましい耐熱性のある硬化膜が得られないことがある。又、脂肪族系のエポキシ樹脂では可とう性は出ても耐熱性が出ないことがある。又、エポキシ当量が１００ｇ／ｅｑ未満では加えるエポキシ樹脂の量が少なくなり、硬化物の架橋密度が密となり、固くて脆いものとなり、可とう性がなくなってしまう。尚、（Ｂ）成分のエポキシ当量は好ましくは、１５０ｇ／ｅｑ〜３５００ｇ／ｅｑ、より好ましくは２００ｇ／ｅｑ〜２５００ｇ／ｅｑである。本発明組成物に適したエポキシ樹脂を例示すると、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Ａ，Ｆ共縮合型エポキシ樹脂、ノボラック型エポキシ樹脂、ビフェニル型エポキシ樹脂、ジシクロペンタジエン−フェノール系共縮合型エポキシ樹脂、、及びそれらのハロゲン置換体等が挙げられる。
【００１５】
本発明に於けるエポキシ樹脂組成物には、銅箔に塗布する時に適度の粘性を保つ為に、溶剤を用いても良い。粘度調整用の溶剤としては、１００℃〜１５０℃の溶剤乾燥時にエポキシ樹脂組成物中に残存しないもので、トルエン、キシレン、メチルエチルケトン、メチルイソブチルケトン、ジオキサン、エタノール、イソプロピルアルコール、メチルセルソルブ、エチルセルソルブ、シクロヘキサノン等が挙げられる。
【００１６】
本発明のエポキシ樹脂組成物では、耐熱性、難燃性の付与、低線膨張率化等の為に、シリカ、炭酸カルシウム、タルク、水酸化アルミニウム、アルミナ、マイカ等を、又、接着力改善の為にエポキシシランカップリング剤や、ゴム成分等をエポキシ樹脂組成物の硬化物物性を落とさない程度に加えても良い。
【００１７】
本発明に用いられる硬化促進剤（（Ｃ）成分）は、エポキシ樹脂に一般的に使用される促進剤で良く、アミン系、イミダゾール系、トリフェニルフォスフォニウム、フォスフォニウム塩系等が用いられる。（Ｃ）成分の使用量は、（Ａ）成分＋（Ｂ）成分に対して、５０ｐｐｍ〜５０，０００ｐｐｍが良く、好ましくは１００ｐｐｍ〜１００００ｐｐｍ、より好ましくは２００ｐｐｍ〜５０００ｐｐｍである。硬化促進剤（（Ｃ）成分）の量が５０ｐｐｍより少ないと加熱硬化時間が長くなりすぎ、不経済である。５０，０００ｐｐｍより多いと、接着剤付き銅箔としての貯蔵安定性がなくなり、商品価値がなくなってしまう。
【００１８】
本発明のエポキシ樹脂組成物を前述した様な溶剤で１５０００ｃｐｓ以下望ましくは１００００ｃｐｓ以下の粘度に調整し、一定の硬化時間を持つように調整された適量の硬化促進剤を加えてワニス化し銅箔に塗布し９０℃〜１５０℃で溶剤を揮発させ接着剤付き銅箔を得る。得られた接着剤付き銅箔を、ドライラミネーター等により内層回路基板にラミネートし加熱硬化させることにより、外層銅箔を有する多層プリント配線板を作成することが出来る。
【００１９】
【実施例、比較例】
以下、合成例、実施例及び比較例に基づき本発明を具体的に説明する。尚、以下の合成例、実施例及び比較例に於いて、「部」は「重量部」を示す。尚、合成例１、２及び比較合成例で使用した触媒はそのまま実施例、比較例における硬化促進剤として作用するものである。
【００２０】
合成例１
ビスフェノールＡジグリシジルエーテルとテトラブロムビスフェノールＡの共縮合物である臭素化ビスフェノールＡ型エポキシ樹脂、具体的にはＹＰＢ−４０Ａ４０（東都化成製、水酸基当量３６４．７ｇ／ｅｑ、エポキシ当量１３５００ｇ／ｅｑ、臭素含有量２５％、シクロヘキサノン溶媒、固形分濃度４０．９％、以下ＮＶ．と略す、重量平均分子量３００００）を６００部、メチルヘキサヒドロ無水フタル酸（無水酸当量：１６８ｇ／ｅｑ）を５０部、触媒として２エチル４メチルイミダゾール０．７部を１ｌのセパラブルフラスコに仕込み、撹拌しながら１１０℃まで徐々に昇温していった。反応温度１０５℃〜１２５℃を保ちながら７時間撹拌した後、シクロヘキサノン８８．５部を加え、酸価５７．２ＫＯＨｍｇ／ｇ、ＮＶ．４０．０％のエポキシ樹脂−酸無水物付加物のシクロヘキサノンワニスを７３８．５部得た。この樹脂を合成樹脂ワニスＩとした。この樹脂の性状を表１に示した。
【００２１】
合成例２
ビスフェノールＡジグリシジルエーテルとテトラブロムビスフェノールＡの共縮合物である臭素化ビスフェノールＡ型エポキシ樹脂、具体的にはＹＰＢ−４０ＸＭ４０（東都化成製、水酸基当量３６５．５ｇ／ｅｑ、エポキシ当量１３０００ｇ／ｅｑ、臭素含有量２５％、キシレン、ＭＥＫ溶媒、ＮＶ．４０．５％、重量平均分子量３００００）を６００部、メチルヘキサヒドロ無水フタル酸（酸無水当量：１６８ｇ／ｅｑ）を３０部、ｎ−ブチルトリフェニルフォスフォニウムブロマイドを１．３部を１ｌのセパラブルフラスコに仕込み、撹拌しながら１１０℃まで徐々に昇温していった。反応温度１０５℃〜１２５℃を保ちながら４時間撹拌した後、ベンゾフェノンテトラカルボン酸二無水物（酸無水当量：２２５ｇ／ｅｑ）を２０部加えさらに４時間撹拌し、水を５部添加してさらに１時間撹拌した後ＭＥＫを７７．５部加え、酸価８５．３ＫＯＨｍｇ／ｇ、ＮＶ．４０．０％のエポキシ樹脂−酸無水物付加物のキシレン、ＭＥＫワニスを７３２．５部得た。この樹脂を合成樹脂ワニスＩＩとした。この樹脂の性状を表１に示した。
【００２２】
合成例３
ビスフェノールＡジグリシジルエーテルとテトラブロムビスフェノールＡの共縮合物である臭素化ビスフェノールＡ型エポキシ樹脂、具体的にはＹＰＢ−４０ＸＭ４０（前述）を６００部、トリメリット酸無水物（酸無水当量：１９２ｇ／ｅｑ）を５１部、トリエチレンジアミン０．５部を１ｌのセパラブルフラスコに仕込み、撹拌しながら１１０℃まで徐々に昇温していった。反応温度１０５℃〜１２５℃を保ちながら５時間撹拌した後ＭＥＫを８４部加え、酸価１０２ＫＯＨｍｇ／ｇ、ＮＶ．４０．０％のエポキシ樹脂−酸無水物付加物のキシレン、ＭＥＫワニス７３５部を得た。この樹脂を合成樹脂ワニスＩＩＩとした。この樹脂の性状を表１に示した。
【００２３】
比較合成例
ビスフェノールＡジグリシジルエーテルとテトラブロムビスフェノールＡの共縮合物である臭素化ビスフェノールＡ型エポキシ樹脂、具体的にはＹＰＢ−４０ＸＭ４０（前述）を６００部、メチルヘキサヒドロ無水フタル酸（無水酸当量：１６８ｇ／ｅｑ）を２３部、触媒として２エチル４メチルイミダゾールを０．７部を１ｌのセパラブルフラスコに仕込み、撹拌しながら１１０℃まで徐々に昇温していった。反応温度１０５℃〜１２５℃を保ちながら７時間撹拌した後ＭＥＫを４２部加え、酸価２８．６ＫＯＨｍｇ／ｇ、ＮＶ．４０．０％のエポキシ樹脂−酸無水物付加物のキシレン、ＭＥＫワニスを６６５部得た。この樹脂を合成樹脂ワニスＩＶとした。この樹脂の性状を表１に示した。
【００２４】
【表１】

【００２５】
実施例１
合成例１で得られた合成樹脂ワニスＩを２２７．５部、ＹＤ−０１４（東都化成製、エポキシ当量９５４ｇ／ｅｑ、軟化点９８℃、ビスフェノールＡ型エポキシ樹脂）を５０部、ＹＤＢ−４００（東都化成製、エポキシ当量４０５ｇ／ｅｑ、軟化点７０℃、臭素含有量４８．５％、臭素化ビスフェノールＡ型エポキシ樹脂）を１６．３部加え、均一に撹拌混合し、エポキシ樹脂組成物ワニスを得た。このワニスを厚さ３５μｍの銅箔のアンカー面に溶剤乾燥後の樹脂厚みが６０μｍになるようにローラーコーターにて塗布し、１３０℃〜１４０℃、１５分で溶剤乾燥を行って接着剤付き銅箔を得た。一方、模擬内層回路基板として、線間２００μｍピッチの銅黒化処理済みのガラスエポキシ銅張両面板積層板を用いた。この模擬内層回路基板の両面に前記の接着剤付き銅箔をドライラミネーターでラミネートし、１７５℃、１時間加熱硬化させて、４層のプリント配線板を得た。
【００２６】
実施例２
合成例１で得られた合成樹脂ワニスＩを２２７．５部、ＹＤＢ−５００ＥＫ８０（東都化成製、エポキシ当量５１５ｇ／ｅｑ、臭素含有量２０．５％、ＭＥＫワニス、ＮＶ．８０％）を５９．７部加え均一に撹拌混合し、エポキシ樹脂組成物ワニスを得た。このワニスを厚さ３５μｍの銅箔のアンカー面に溶剤乾燥後の樹脂厚みが６０μｍになるようにローラーコーターにて塗布し、溶剤乾燥を行って接着剤付き銅箔を得た以外は実施例１と全く同様にしてプリント配線板を得た。
【００２７】
実施例３
合成例１で得られた合成樹脂ワニスＩを２２７．５部、ＹＤ−０１４（前述）を５０部、ＹＤＢ−４００（前述）を１６．３部、熔融シリカ（電気化学製ＦＤ−２０１Ｓ）を３０部加え、均一に撹拌混合し、エポキシ樹脂組成物ワニスを得た以外は実施例１と全く同様にしてプリント配線板を得た。
【００２８】
実施例４
合成例２で得られた合成樹脂ワニスＩＩを２２４部、ＹＤ−０１４（前述）を５０部、ＹＤＢ−４００（前述）を２０部、ＹＤＦ−１７０（東都化成製、エポキシ当量１７３ｇ／ｅｑ、ビスフェノールＦ型エポキシ樹脂）を６部、トリフェニルフォスフィンを０．７部加え均一に撹拌混合し、エポキシ樹脂組成物ワニスを得た以外は実施例１と全く同様にしてプリント配線板を得た。
【００２９】
実施例５
合成例２で得られた合成樹脂ワニスＩＩを２２４部、ＹＤＢ−５００ＥＫ８０（前述）を８７．８部、トリフェニルフォスフィンを０．５部加え均一に撹拌混合し、エポキシ樹脂組成物ワニスを得た以外は実施例１と全く同様にしてプリント配線板を得た。
【００３０】
実施例６
合成例３で得られた合成樹脂ワニスＩＩＩを２２６部、ＹＤＢ−５００ＥＫ８０（前述）を１０５．８部加え均一に撹拌混合し、エポキシ樹脂組成物ワニスを得た以外は実施例１と全く同様にしてプリント配線板を得た。
【００３１】
実施例７
合成例３で得られた合成樹脂ワニスＩＩＩを２２６部、ＹＤＢ−４００（前述）を２５部、ＹＤ−１２８（東都化成製、エポキシ当量１８５ｇ／ｅｑ、ビスフェノールＡ型エポキシ樹脂）を１９部、ＭＥＫを５０部加え均一に撹拌混合し、エポキシ樹脂組成物ワニスを得た以外は実施例１と全く同様にしてプリント配線板を得た。
【００３２】
比較例１
比較合成例で得られた合成樹脂ワニスＩＶを２１４部、ＹＤＢ−５００ＥＫ８０（前述）を２８．１部加え均一に撹拌混合し、エポキシ樹脂組成物ワニスを得た以外は実施例１と全く同様にしてプリント配線板を得た。
【００３３】
比較例２
合成例１で得られた合成樹脂ワニスＩを２２７．５部、ＹＤ−０２０（東都化成製、エポキシ当量４８５０ｇ／ｅｑ、軟化点１４３℃、ビスフェノールＡ型エポキシ樹脂）のＮＶ．６０％ＭＥＫ溶液７５０部を加え均一に撹拌混合し、エポキシ樹脂組成物ワニスを得た以外は実施例１と全く同様にしてプリント配線板を得た。
【００３４】
以上のようにして作成した多層プリント配線板の特性値を表２に示した。
【００３５】
【表２】

【００３６】
（試験方法）
半田耐熱性試験：１００℃、２時間煮沸後のサンプルを、ｎ＝５で、２６０℃の半田浴に浸け、全て２０秒以上膨れや剥がれを生じなかったものを〇とした。
回路埋め込み性：外層銅箔を剥がした後の内層回路に、樹脂が埋め込まれているものを○とした。
ガラス転移温度：接着剤付き銅箔をラミネートせずにそのまま加熱硬化させて、銅箔を剥がしたフィルムでＴＭＡ測定を行った。
【００３７】
【発明の効果】
本発明によるエポキシ樹脂組成物を用いると、ガラスクロスを用いたプリプレグを作成せずに、単に接着剤付き銅箔をラミネートするだけで外層銅箔を有する耐熱性の有る多層プリント配線板を作成でき、製造工程の単純化や製造コストの低減化が可能となる。一方、ガラスクロスを用いない為、極薄の多層プリント配線板を作成することが可能となる。[0001]
[Industrial application fields]
The present invention has excellent embeddability in the inner layer circuit, adhesion to the circuit board, and excellent smoothness of the outer layer circuit after lamination. The present invention relates to an epoxy resin composition for printed wiring boards.
[0002]
[Prior art]
Conventionally, multilayer printed wiring boards are laminated on a circuit-formed interior circuit board by prepreg sheet that has been impregnated with epoxy resin and then B-staged on glass cloth, and copper foil is further stacked on the prepreg sheet to form by pressure and heating. The manufacturing method of doing is taken. However, in this method, it takes equipment and time to make a prepreg by impregnating epoxy resin into a glass cloth to make a B-stage. It took a lot of equipment and time, and it was expensive. Moreover, since the glass cloth was used, the interlayer thickness could not be made extremely thin.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a heat-resistant epoxy resin composition that can be reduced in the cost of a multilayer printed wiring board and can be extremely thinned, which cannot be achieved by conventional techniques.
[0004]
[Means and Actions for Solving the Problems]
The present invention has solved the above-mentioned problems, the component (A) is represented by the following formula 1 (chemical formula 1), and the molecular weight range is 10,000 to 200,000 (gel permeation chromatography measurement, in terms of standard polystyrene) Weight average molecular weight, hereinafter referred to as the weight average molecular weight according to this measuring method), epoxy resin-acid anhydride addition having a halogen content of 5% to 40% by weight and an acid value of 30 mgKOH / g to 250 mgKOH / g (B) component is an epoxy epoxy resin having an epoxy equivalent of 4500 g / eq to 100 g / eq, and (C) component is a composition composed of a curing accelerator, and in some cases for viscosity adjustment An epoxy resin composition having the ability to form a thermosetting insulating layer containing an organic solvent and organic and inorganic fillers, and the proportion of the component (A) is (A) + (B Epoxy resin composition is 75% to 20% by weight relative to, and this epoxy resin composition with a copper foil for a printed wiring board adhesives formed by applying a copper foil. And this copper foil with an adhesive is used for an ultra-thin, low-cost, heat-resistant multilayer printed wiring board by thermosetting after lamination on an inner layer circuit board.
[Chemical 1]
(In Formula 1, R ¹ and R ² are any one of a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and a halogen atom, and X is —SO ₂ —, —CH ₂ —, —C (CH ₃ ) ₂ —. , —O—, and l represents 0 or 1. R ³ is either a hydrogen atom or Formula 2 (Chemical Formula 2), and the proportion of hydrogen atoms is 85% or less of the total R ³ .
[Chemical formula 2]
In Formula 2, Y represents an acid anhydride residue, and is an integer of m = 1 to 3.
Z represents either Formula 3 (Chemical Formula 3) or —R ³ .
[Chemical 3]
)
[0005]
As a matter of course, the epoxy resin composition in the present invention satisfies various properties such as heat resistance, flame retardancy, and electrical insulation equivalent to those of a glass epoxy circuit board, and when applied to a copper foil. In addition, copper foil curl after solvent volatilization and powder falling off during cutting must be avoided. Further, when laminated on the inner layer circuit board, the inner layer circuit must be embedded.
[0006]
When the molecular weight of the component (A) is less than 10,000, the copper foil with adhesive after the epoxy resin composition is applied to the copper foil and dried causes copper foil curling, powder falling at the time of cutting, etc. It becomes a good product. On the other hand, when the molecular weight exceeds 200,000, even if diluted with a solvent, the solution viscosity is too high at 70% to 40% by weight, which is a normal solvent amount, and it becomes difficult to apply to copper foil. . In order to obtain a solution viscosity that can be applied to the copper foil, a large amount of unfavorable solvent must be added, which is uneconomical and not good for the environment. In addition, the molecular weight of (A) component becomes like this. Preferably it is 15,000-160,000, More preferably, it is 20,000-100,000.
[0007]
If the halogen content of the component (A) is less than 5% by weight, the epoxy resin composition of the present invention cannot provide sufficient flame retardancy, and if it is 40% by weight or less, sufficient flame retardancy is imparted. Since it can, it is not necessary to exceed 40% by weight.
[0008]
When the acid value of the component (A) is less than 30 mgKOH / g, the crosslinking density when cured becomes low and the desired heat resistance does not appear. In addition, when an attempt is made to synthesize a resin exceeding 250 mgKOH / g, a large amount of bifunctional or higher acid anhydride must be used, and addition polymerization is performed during the synthesis of epoxy resin-anhydride (component (A)). It reacts and gels, making synthesis very difficult.
[0009]
In order to synthesize the resin of component (A), the molecular weight of the acid anhydride must be considered, but a relatively high molecular weight epoxy resin must be used. Relatively high molecular weight epoxy resins are obtained by direct reaction of bisphenol A (BPA) or / and tetrabromobisphenol A (TBA) with epichlorohydrin, or by addition polymerization of BPA or / and TBA diglycidyl ether and BPA or / and TBA. Although a method is known, any method may be used. Further, both ends of the polymer epoxy resin are epoxy groups (in this case, the terminal group of formula 1 is a group represented by formula 3), or a part or all of the terminal groups are phenolic hydroxyl groups ( In this case, a modified polymer epoxy resin in which the terminal group of Formula 1 is R ³ ) may be used.
[0010]
The blending ratio of the (A) component and the (B) component of the epoxy resin composition is most preferably 1: 1 as the equivalent ratio of the carboxylic acid group of the (A) component and the epoxy group of the (B) component. ) When the proportion of the component (A) in the component (B) exceeds 75% by weight, the solution viscosity is too high at 70% to 40% by weight, which is the usual solvent amount, and a large amount of unfavorable solvent is used. It must be added, is uneconomical, and is not good for the environment. On the other hand, if it is less than 20% by weight, the heat resistance when cured will be insufficient, and the coating film performance of the copper foil with adhesive will deteriorate, causing phenomena such as copper foil curl and powder falling off during cutting. become. Specifically, the epoxy resin for acid anhydride addition is a single or respective co-condensation type epoxy resin such as bisphenol A type, F type, S type, etc. , All halogenated ones are used.
[0011]
Acid anhydrides include maleic anhydride, succinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, biphenyltetra Carboxylic dianhydride, biphenyl ether tetracarboxylic dianhydride and the like are used.
[0012]
The reaction between the epoxy resin and the acid anhydride involves dissolving the epoxy resin in an inert solvent such as xylene, toluene, methyl ethyl ketone, diethyl cellosolve, methyl cellosolve acetate, methyl ethyl carbitol, etc. Add or react in batches or divided. At this time, when a catalyst is added, a general catalyst used for epoxy synthesis may be used, and a catalyst such as imidazole, triphenylphosphine, phosphonium salt or the like is used. The reaction temperature is 90 ° C to 150 ° C, preferably 115 ° C to 125 ° C.
[0013]
The epoxy resin-anhydride adduct (component (A)) synthesized in this way is the only one, and the resin flow during molding is small, the circuit embedding property is good, and the material has flexibility and flame retardancy. However, the heat resistance is slightly insufficient. Therefore, in order to have heat resistance, it is necessary to add an epoxy resin and heat cure.
[0014]
The epoxy resin as the component (B) is one that increases heat resistance without deteriorating physical properties such as flexibility after curing, and is preferably aromatic and has an epoxy equivalent of 4500 g / eq to 100 g / eq. When the epoxy equivalent exceeds 4500 g / eq, the amount of epoxy resin to be added is increased, the physical properties of the epoxy resin-anhydride adduct (component (A)) are impaired, and the crosslinking density is lowered, which is desirable heat resistance. A cured film having properties may not be obtained. In addition, aliphatic epoxy resins may be flexible but not heat resistant. On the other hand, if the epoxy equivalent is less than 100 g / eq, the amount of epoxy resin added is small, the cross-linking density of the cured product becomes dense, hard and brittle, and flexibility is lost. The epoxy equivalent of the component (B) is preferably 150 g / eq to 3500 g / eq, more preferably 200 g / eq to 2500 g / eq. Examples of the epoxy resin suitable for the composition of the present invention are bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol A, F co-condensation type epoxy resin, novolac type epoxy resin, biphenyl type epoxy resin, dicyclopentadiene-phenol. Examples thereof include system cocondensation type epoxy resins, and halogen-substituted products thereof.
[0015]
In the epoxy resin composition in the present invention, a solvent may be used in order to maintain an appropriate viscosity when applied to the copper foil. As a solvent for viscosity adjustment, it does not remain in the epoxy resin composition when the solvent is dried at 100 ° C. to 150 ° C., and is toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, dioxane, ethanol, isopropyl alcohol, methyl cellosolve, ethyl. Cellsolve, cyclohexanone, etc. are mentioned.
[0016]
In the epoxy resin composition of the present invention, silica, calcium carbonate, talc, aluminum hydroxide, alumina, mica, etc. are used for improving heat resistance, flame resistance, low linear expansion, etc. Therefore, an epoxy silane coupling agent, a rubber component, or the like may be added to such an extent that the cured product properties of the epoxy resin composition are not deteriorated.
[0017]
The curing accelerator (component (C)) used in the present invention may be an accelerator generally used for epoxy resins, and amine-based, imidazole-based, triphenylphosphonium, phosphonium salt-based, etc. are used. It is done. The amount of component (C) used is preferably 50 ppm to 50,000 ppm, preferably 100 ppm to 10000 ppm, more preferably 200 ppm to 5000 ppm with respect to component (A) + component (B). If the amount of the curing accelerator (component (C)) is less than 50 ppm, the heat curing time becomes too long, which is uneconomical. When it is more than 50,000 ppm, the storage stability as a copper foil with an adhesive is lost, and the commercial value is lost.
[0018]
The epoxy resin composition of the present invention is adjusted to a viscosity of 15000 cps or less, preferably 10,000 cps or less with a solvent as described above, and an appropriate amount of a curing accelerator adjusted to have a certain curing time is added to varnish to form a copper foil. Apply and volatilize the solvent at 90 ° C to 150 ° C to obtain a copper foil with adhesive. A multilayer printed wiring board having an outer layer copper foil can be produced by laminating the obtained copper foil with an adhesive on an inner layer circuit board with a dry laminator or the like and curing it by heating.
[0019]
[Examples and comparative examples]
Hereinafter, the present invention will be specifically described based on synthesis examples, examples, and comparative examples. In the following synthesis examples, examples and comparative examples, “part” means “part by weight”. In addition, the catalysts used in Synthesis Examples 1 and 2 and Comparative Synthesis Examples act as curing accelerators in Examples and Comparative Examples as they are.
[0020]
Synthesis example 1
Brominated bisphenol A type epoxy resin which is a cocondensate of bisphenol A diglycidyl ether and tetrabromobisphenol A, specifically YPB-40A40 (manufactured by Tohto Kasei, hydroxyl group equivalent 364.7 g / eq, epoxy equivalent 13500 g / eq, Bromine content 25%, cyclohexanone solvent, solid content concentration 40.9%, hereinafter abbreviated as NV., Weight average molecular weight 30000) 600 parts, methylhexahydrophthalic anhydride (anhydric acid equivalent: 168 g / eq) 50 parts As a catalyst, 0.7 part of 2-ethyl 4-methylimidazole was charged into a 1 l separable flask, and gradually heated to 110 ° C. with stirring. After stirring for 7 hours while maintaining the reaction temperature at 105 ° C. to 125 ° C., 88.5 parts of cyclohexanone was added, and the acid value was 57.2 KOH mg / g, NV. 738.5 parts of cyclohexanone varnish of 40.0% epoxy resin-anhydride adduct was obtained. This resin was named synthetic resin varnish I. The properties of this resin are shown in Table 1.
[0021]
Synthesis example 2
Brominated bisphenol A type epoxy resin which is a co-condensate of bisphenol A diglycidyl ether and tetrabromobisphenol A, specifically YPB-40XM40 (manufactured by Tohto Kasei, hydroxyl group equivalent 365.5 g / eq, epoxy equivalent 13000 g / eq, 600 parts of bromine content 25%, xylene, MEK solvent, NV. 40.5%, weight average molecular weight 30000), 30 parts of methylhexahydrophthalic anhydride (acid anhydride equivalent: 168 g / eq), n-butyltri 1.3 parts of phenylphosphonium bromide were charged into a 1 l separable flask and gradually heated to 110 ° C. with stirring. After stirring for 4 hours while maintaining the reaction temperature of 105 ° C. to 125 ° C., 20 parts of benzophenonetetracarboxylic dianhydride (acid anhydrous equivalent: 225 g / eq) was added and stirred for another 4 hours, and 5 parts of water was further added. After stirring for 1 hour, 77.5 parts of MEK was added, and the acid value was 85.3 KOHmg / g, NV. 732.5 parts of xylene and MEK varnish of 40.0% epoxy resin-anhydride adduct were obtained. This resin was designated as synthetic resin varnish II. The properties of this resin are shown in Table 1.
[0022]
Synthesis example 3
Brominated bisphenol A type epoxy resin, which is a cocondensate of bisphenol A diglycidyl ether and tetrabromobisphenol A, specifically 600 parts of YPB-40XM40 (described above), trimellitic anhydride (acid anhydrous equivalent: 192 g / eq) (51 parts) and triethylenediamine (0.5 parts) were charged into a 1 l separable flask and gradually heated to 110 ° C. with stirring. After stirring for 5 hours while maintaining the reaction temperature at 105 ° C to 125 ° C, 84 parts of MEK was added, and the acid value was 102 KOHmg / g, NV. As a result, 735 parts of xylene and MEK varnish of 40.0% epoxy resin-anhydride adduct were obtained. This resin was designated as synthetic resin varnish III. The properties of this resin are shown in Table 1.
[0023]
Comparative Synthesis Example Brominated bisphenol A type epoxy resin, which is a cocondensate of bisphenol A diglycidyl ether and tetrabromobisphenol A, specifically 600 parts of YPB-40XM40 (described above), methylhexahydrophthalic anhydride (acid anhydride) Equivalent: 168 g / eq) 23 parts and 0.7 part of 2-ethyl 4-methylimidazole as a catalyst were charged into a 1 l separable flask and gradually heated to 110 ° C. with stirring. After stirring for 7 hours while maintaining the reaction temperature at 105 ° C. to 125 ° C., 42 parts of MEK was added, and the acid value was 28.6 KOH mg / g, NV. 665 parts of xylene and MEK varnish of 40.0% epoxy resin-anhydride adduct were obtained. This resin was designated as synthetic resin varnish IV. The properties of this resin are shown in Table 1.
[0024]
[Table 1]

[0025]
Example 1
227.5 parts of the synthetic resin varnish I obtained in Synthesis Example 1, 50 parts of YD-014 (manufactured by Tohto Kasei, epoxy equivalent 954 g / eq, softening point 98 ° C., bisphenol A type epoxy resin), YDB-400 ( 16.3 parts of Toto Kasei Co., Ltd., epoxy equivalent 405 g / eq, softening point 70 ° C., bromine content 48.5%, brominated bisphenol A type epoxy resin), and uniformly stirred and mixed to obtain an epoxy resin composition varnish Obtained. This varnish was applied to the anchor surface of a 35 μm thick copper foil with a roller coater so that the resin thickness after solvent drying would be 60 μm, and the solvent was dried at 130 ° C. to 140 ° C. for 15 minutes, and the copper with adhesive A foil was obtained. On the other hand, a glass epoxy copper clad double-sided laminated board having a copper blackening treatment with a pitch of 200 μm between lines was used as a simulated inner layer circuit board. The copper foil with the adhesive was laminated on both sides of the simulated inner layer circuit board with a dry laminator, and heat cured at 175 ° C. for 1 hour to obtain a four-layer printed wiring board.
[0026]
Example 2
227.5 parts of synthetic resin varnish I obtained in Synthesis Example 1 and 59. YDB-500EK80 (manufactured by Tohto Kasei, epoxy equivalent 515 g / eq, bromine content 20.5%, MEK varnish, NV. 80%). 7 parts was added and stirred and mixed uniformly to obtain an epoxy resin composition varnish. Example 1 except that this varnish was applied to a 35 μm thick copper foil anchor surface with a roller coater so that the resin thickness after solvent drying was 60 μm, and solvent drying was performed to obtain a copper foil with adhesive. A printed wiring board was obtained in exactly the same manner.
[0027]
Example 3
227.5 parts of the synthetic resin varnish I obtained in Synthesis Example 1, 50 parts of YD-014 (described above), 16.3 parts of YDB-400 (described above), fused silica (FD-201S manufactured by Electrochemical Co., Ltd.) A printed wiring board was obtained in the same manner as in Example 1 except that 30 parts were added and uniformly mixed by stirring to obtain an epoxy resin composition varnish.
[0028]
Example 4
224 parts of the synthetic resin varnish II obtained in Synthesis Example 2, 50 parts of YD-014 (previously described), 20 parts of YDB-400 (previously described), YDF-170 (manufactured by Tohto Kasei, epoxy equivalent 173 g / eq, bisphenol) A printed wiring board was obtained in the same manner as in Example 1 except that 6 parts of F-type epoxy resin and 0.7 parts of triphenylphosphine were added and stirred and mixed uniformly to obtain an epoxy resin composition varnish.
[0029]
Example 5
224 parts of the synthetic resin varnish II obtained in Synthesis Example 2, 87.8 parts of YDB-500EK80 (described above) and 0.5 part of triphenylphosphine were added and stirred uniformly to obtain an epoxy resin composition varnish. A printed wiring board was obtained in the same manner as in Example 1 except that.
[0030]
Example 6
226 parts of the synthetic resin varnish III obtained in Synthesis Example 3 and 105.8 parts of YDB-500EK80 (described above) were added and stirred and mixed uniformly to obtain an epoxy resin composition varnish, exactly as in Example 1. A printed wiring board was obtained.
[0031]
Example 7
226 parts of the synthetic resin varnish III obtained in Synthesis Example 3, 25 parts of YDB-400 (described above), 19 parts of YD-128 (manufactured by Tohto Kasei, epoxy equivalent 185 g / eq, bisphenol A type epoxy resin), MEK A printed wiring board was obtained in exactly the same manner as in Example 1 except that 50 parts of the above was added and stirred and mixed uniformly to obtain an epoxy resin composition varnish.
[0032]
Comparative Example 1
214 parts of the synthetic resin varnish IV obtained in the comparative synthesis example and 28.1 parts of YDB-500EK80 (described above) were added and stirred and mixed uniformly to obtain an epoxy resin composition varnish, exactly as in Example 1. A printed wiring board was obtained.
[0033]
Comparative Example 2
227.5 parts of the synthetic resin varnish I obtained in Synthesis Example 1 and YD-020 (manufactured by Tohto Kasei, epoxy equivalent 4850 g / eq, softening point 143 ° C., bisphenol A type epoxy resin) NV. A printed wiring board was obtained in exactly the same manner as in Example 1 except that 750 parts of a 60% MEK solution was added and uniformly stirred and mixed to obtain an epoxy resin composition varnish.
[0034]
Table 2 shows the characteristic values of the multilayer printed wiring board produced as described above.
[0035]
[Table 2]

[0036]
(Test method)
Solder heat resistance test: Samples boiled for 2 hours at 100 ° C. were immersed in a solder bath at 260 ° C. with n = 5, and all samples that did not swell or peel for 20 seconds or more were evaluated as “good”.
Circuit embedding property: A case where the resin was embedded in the inner layer circuit after the outer layer copper foil was peeled off was marked as ◯.
Glass transition temperature: TMA measurement was performed on a film in which the copper foil with adhesive was heat cured without being laminated and the copper foil was peeled off.
[0037]
【The invention's effect】
When the epoxy resin composition according to the present invention is used, a heat-resistant multilayer printed wiring board having an outer layer copper foil can be produced simply by laminating a copper foil with an adhesive without producing a prepreg using a glass cloth. It is possible to simplify the manufacturing process and reduce the manufacturing cost. On the other hand, since a glass cloth is not used, an extremely thin multilayer printed wiring board can be produced.

Claims

The component (A) is represented by the following formula 1 (chemical formula 1), the molecular weight range is 10,000 to 200,000, the halogen content is 5% to 40% by weight, and the acid value is 30 mgKOH / g to 250 mgKOH / g. It is an epoxy resin-anhydride adduct, the component (B) is an epoxy resin, the component (C) is composed of a curing accelerator, and the content of the component (A) is 20 to 75% by weight. An epoxy resin composition having the ability to form a thermosetting insulating layer.

(In Formula 1, R ¹ and R ² are any one of a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and a halogen atom, and X is —SO ₂ —, —CH ₂ —, —C (CH ₃ ) ₂ —. , —O—, and l represents 0 or 1. R ³ is either a hydrogen atom or Formula 2 (Chemical Formula 2), and the proportion of hydrogen atoms is 85% or less of the total R ³ .

In formula 2, Y represents an acid anhydride residue, and is an integer of m = 1 to 3.
Z represents either Formula 3 (Formula 3) or —R ³ .

)

The epoxy resin according to claim 1, wherein the epoxy resin of component (B) is an aromatic epoxy resin and has an epoxy equivalent of 4500 g / eq to 100 g / eq. Resin composition.

A copper foil with an adhesive for printed wiring boards, wherein the epoxy resin composition according to claim 1 or 2 is applied to a copper foil.