JP4766796B2

JP4766796B2 - Release film

Info

Publication number: JP4766796B2
Application number: JP2001245933A
Authority: JP
Inventors: 道央笹沼; 益史林; 基桐谷
Original assignee: Fujimori Kogyo Co Ltd
Current assignee: Fujimori Kogyo Co Ltd
Priority date: 2001-08-14
Filing date: 2001-08-14
Publication date: 2011-09-07
Anticipated expiration: 2021-08-14
Also published as: JP2003053896A

Description

【０００１】
【発明の属する技術分野】
本発明は、導体箔積層板製造時のプリプレグプレス工程において使用される離型フィルムに関し、詳細には、電子機器などに広範に使用される積層配線基板の製造に好適に用いられる離型フィルムに関する。
【０００２】
【従来の技術】
従来、多層の導体回路を有する積層配線基板の製造方法としては、片面又は両面に導体回路を有する内層材にプリプレグを積層し、その最外層に導体箔を配置し、熱プレスして一体化させる方法が一般的である。このような方法においては、プリプレグから生じた粉末物や他の異物が導体箔上に入り込みやすく、これが原因となって導体箔に局部的な圧力がかかり、導体箔の表面に打痕が生じる懸念がある。
この問題を防止するため、導体箔と鏡面板との間に樹脂等により形成された離型フィルムを配置し、異物による局部的な圧力を緩和させるやり方が提案されている。離型フィルムはあらかじめ所定の大きさに断裁され、重ねた状態で積層配線基板の製造工程に供給される。積層配線基板の製造工程では、導体箔やプリプレグと離型フィルムとを積層し、加熱プレスすることになるが、この積層の際に導体箔やプリプレグ、離型フィルムの位置合わせが必要となる。このため積層配線基板の製造工程に供給される離型フィルムには、位置合わせ用として数カ所にピン穴を施すのが一般的である。このピン穴は、離型フィルム１枚ずつに穴あけを行うのではなく、通常は、断裁し積み重ねた状態で１度に穴を開ける方法をとる。
【０００３】
積層配線基板の製造工程では、離型フィルムと所定の大きさに断裁されたプリプレグ、銅箔等を積層して、熱プレスにより積層配線基板を作成する。
このような離型フィルムとしては、ポリエチレンテレフタレートフィルムに代表されるポリエステルフィルムの片面ないし両面にシリコーンなどの離型剤を塗布したフィルム、フッ素系フィルムやポリオレフィン系フィルムなどが用いられていた。しかしながら、ポリエチレンテレフタレートフィルムの片面ないし両面にシリコーンなどの離型剤を塗布したフィルムでは、積層配線基板の製造時の熱プレス時に剥離剤の成分が、熱プレス時に離型フィルムと接していたプリプレグや銅箔等の表面に移行し、プリプレグや銅箔等の表面濡れ性を低下させる問題があった。
プリプレグや銅箔等の表面濡れ性が低下した場合、そのままの状態で得られた積層体に、さらに他のプリプレグや銅箔等を積層する際には、離型剤が移行した表面の密着性が悪くなってしまう懸念があるため、熱プレス時に離型フィルムと接していたプリプレグや銅箔等の表面を研磨して移行した離型剤を除去する工程を要し、作業性が悪いという問題があった。
【０００４】
また、従来のポリエチレンテレフタレートフィルムの片面ないし両面にシリコーンなどの離型剤を塗布したフィルムは、積層配線基板の製造時の熱プレス工程では耐熱性、離型性が良好で使用しやすいが、積層工程に供給する前の工程で、離型フィルムを所定のサイズに断裁して重ねたときに、離型剤面が滑りやすいために、離型フィルムを重ねた時に滑ってしまい、重ね難いという問題もあった。また、離型フィルム断裁積重ね品にピン穴を開ける工程でも、離型フィルムが滑り易いと、穴あけ時に位置がずれてしまう虞があった。
一方、離型フィルムを断裁せずに、ロール状態で熱プレス工程に供給し、ロールトゥーロールで連続的に熱プレスする方法もあるが、この場合でも離型面が滑りやすいため、ロール状に巻いた離型フィルムが巻ずれを起こしやすく、ロールの取り扱いに注意が必要となり、一度巻ずれが発生した場合には、熱プレス工程でのプレス機に掛からない問題があった。
【０００５】
フッ素系フィルムやポリオレフィン系フィルムを用いた場合には、このような離型剤に起因する積重ね時の作業性の悪さや穴あけ時の位置ずれの問題等は見られないものの、フッ素系フィルムは、それ自体が高価なため、製造費が高くなる問題があり、また、ポリオレフィン系フィルムを用いた場合には、ポリオレフィン系フィルム自体の耐熱性が乏しいため、プレス時に１２０℃以上の温度になる用途には使用出来ないという問題があった。
【０００６】
【発明が解決しようとする課題】
本発明は、上記のような問題点を解決するためになされたもので、加熱プレスした後のプリプレグや銅箔などの表面の濡れ性を低下させることなく、離型フィルムの断裁、積重ね、ピン穴の開口、搬送などの各工程において、離型フィルムがずれにくく、作業性に優れており、安価な離型フィルムを提供するものである。また、本発明の他の目的は、ロール状態で扱われた際にも、巻きずれが発生しにくく、且つ、繰り出し時の静電気の発生が少ない離型フィルムを提供することにある。
【０００７】
【課題を解決するための手段】
本発明者らは、加熱プレスした後のプリプレグや銅箔などの表面の濡れ性が良好な離型剤を検討するにあたり、得られた積層体に、さらに他のプリプレグや銅箔等を積層する際には、離型剤がどの程度移行するとプリプレグ樹脂の密着性を低下させるのかを検討した。その結果、所定の物性とそれを実現するための添加剤とを見出し、本発明を完成した。
【０００８】
即ち、本発明の離型フィルムは、合成樹脂フィルムの両面にシリコーン系離型剤を含み、互いに組成の異なる離型剤をそれぞれ塗布した離型フィルムであって、一方の面に塗布された離型剤が、セルロース誘導体を含まないシリコーン系離型剤であり、他方の面に塗布された離型剤が、シリコーン系離型剤とセルロース誘導体の混合物であり、且つ、下記（１）の条件を満たす物性を有することを特徴とする。
（１）前記シリコーン系離型剤とセルロース誘導体の混合物である離型剤を塗布されてなる離型剤塗布表面と、２軸延伸ポリエチレンテレフタレートフィルムを重ね合わせ、１８０℃、３０ａｔｍの条件で２０分プレス処理をしたのち、２軸延伸ポリエチレンテレフタレートフィルムを剥がし、フィルムの離型剤塗布表面と接していた部分の濡れ性をＪＩＳＫ６７６８に規定する方法で測定したときに、表面の濡れ性が３２ｍＮ／ｍ以上であること。
即ち、本発明者は、離型剤塗布表面と２軸延伸ポリエチレンテレフタレートフィルムを重ね合わせ、所定の条件下で加熱プレスした後の、ポリエチレンテレフタレートフィルム表面の濡れ性が３２ｍＮ／ｍ以上であれば、加熱プレス処理してできた積層板を研磨することなく、他のプリプレグや銅箔等を積層できることを見出し、このような物性を有する離型剤を用いた離型フィルムの発明をなした。
【０００９】
また、本発明においては、前記合成樹脂フィルムの両面に設けられた離型剤のうち片面の離型剤が、シリコーン系離型剤とセルロース誘導体の混合物であり、該離型剤による処理表面同士の静摩擦係数が０．１０〜０．５０の範囲にある物性を有するが、この条件を満たすことにより、離型フィルム断裁後の積重ね時に離型フィルムが積み重ね易く、かつピン穴を開ける際にも離型フィルムがずれにくくなるという、さらなる改良を実現することができる。即ち、離型剤塗布表面の静摩擦抵抗をある程度高くしないと、離型フィルム断裁後に離型フィルムを積み重ねた時にずれが生じやすくなり、積重ね時に崩れたり、ピン穴を開ける際にもずれたり、ロール状態で熱プレス工程に供給する際にも、巻ずれが生じやすくなるものの、静摩擦係数が高すぎると、積重ねてある離型フィルムから離型フィルムを１枚とる場合にとりにくくなり、積層配線基板の製造時の熱プレス工程での作業性が悪くなる。このため、最適な離型剤塗布表面同士の静摩擦係数の範囲を見出したものである。また、この製摩擦係数の範囲であれば、ロール状態で使用した際、ロール繰出し時の摩擦による静電気の発生を抑制することができ、作業環境中の塵や埃の静電気による吸着や、積層配線基板中への異物の混入を防止できる。このため、離型剤塗布表面の静摩擦抵抗が０．１０以上０．５０以下の値のものを使用することにより、断裁工程や熱プレス工程での作業性が著しく向上する。
【００１０】
本発明の請求項２に係る離型フィルムは、合成樹脂フィルムの片面にシリコーン系離型剤を塗布し、他の面にシリコーン系離型剤とエチルセルロースの混合物であり、且つ、シリコーン系離型剤とセルロース誘導体の混合物の処理表面の静摩擦係数が０．１０〜０．５０の範囲にあることを特徴とする。
この合成樹脂フィルムとしては、製品のコストおよび耐熱性の点から、ポリエステル系フィルムが好ましく、このフィルムの両面にシリコーンなどの離型剤を塗布したフィルムが好適であるが、両面に離型剤を塗布する場合、本発明の効果である表面濡れ性を改良した離型剤、即ち、シリコーン系離型剤とセルロース誘導体の混合物からなる離型剤は片面に塗布すればよく、濡れ性の改良を必要としない面には、剥離性、耐熱性に優れた従来のシリコーン系離型剤を使用すればよい。
【００１１】
【発明の実施の形態】
以下に、本発明を詳細に説明する。
本発明の離型フィルムは、基材としての合成樹脂フィルムの両面にシリコーン系離型剤を含み、互いに組成の異なる離型剤をそれぞれ塗布し、離型剤層を設けたものである。
本発明の離型フィルムにおいて基材として用いられるフィルムは、合成樹脂フィルムのうち、加熱プレス時に適度な弾力性があり、かつ、加熱に耐え得るフィルムが用いられる。
基材となる合成樹脂フィルムは、上記の点を満足するものであれは、特に制限を受けるものではなく、具体的には、ポリオレフィン系フィルム、ポリエステル系フィルム、ポリアミド系フィルム、ポリイミド系フィルム、ポリフェニレンサルファイドフィルム、ポリエーテルエーテルケトンフィルム、塩化ビニル系フィルム、塩化ビニリデン系フィルム、ポリビニルアルコール系フィルム、フッ素系フィルムなどが挙げられる。
耐熱性やコストの観点からポリエステル系フィルムもしくはポリアミド系フィルムが好適であり、さらに吸湿時の寸法安定性の観点からポリエステル系樹脂フィルムがより好適である。ポリエステル系樹脂フィルムとしては、耐熱性の観点からは芳香族のポリエステルが好ましい。本発明に好適に用いられるものとしては、具体的には、ポリエチレンテレフタレートフィルム、ポリブチレンテレフタレートフィルム、ポリエチレンイソフタレートフィルム、ポリエチレンナフタレートフィルム、ポリエチレンアジペートフィルム、ポリエチレン系液晶ポリマーフィルム、ポリエステル系熱硬化性樹脂や上記樹脂の混合樹脂フィルムなどが挙げられ、なかでも、耐熱性、コストの観点からポリエチレンテレフタレートフィルム、ポリエチレンナフタレートフィルムが特に好適である。
【００１２】
合成樹脂フィルムは、前記合成樹脂を既知の方法により成膜したフィルムを用いればよい。また、未延伸、１軸延伸、２軸延伸の何れでもよいが、耐熱性の観点からは２軸延伸フィルムが好ましい。フィルムの厚さは特に制限されないが、耐熱性、機械的強度およびコストなどの観点から２５〜１２５μｍ程度が望ましい。
フィルムは透明、半透明、着色何れでもよく、必要に応じて帯電防止剤塗布したものであってもよい。また、表面にコロナ処理や易接着剤塗工、マット化処理を施したものを使用してもよい。
【００１３】
本発明の離型フィルムは、前記合成樹脂フィルムの片面或いは両面に離型剤を塗布したものであり、片面の場合にはその離型剤が、また、両面に塗布する場合には、その少なくとも片面の離型剤が、シリコーン系離型剤とセルロース誘導体の混合物からなる離型剤（以下、適宜、特定シリコーン系離型剤と称する）であることを特徴とする。シリコーン系離型剤にセルロース誘導体を混合することにより、シリコーン系離型剤にて問題となるシリコーン移行や離型剤塗布表面の滑り性を抑えることができる。
【００１４】
まず、特定シリコーン系離型剤の好ましい物性について説明する。
具体的な離型剤移行度合いの目安は、離型剤塗布表面と２軸延伸ポリエチレンテレフタレートフィルムを重ね合わせ、１８０℃、３０ａｔｍの条件で２０分プレス処理をしたのちの、ポリエチレンテレフタレートフィルム表面の濡れ性が３２ｍＮ／ｍ以上あると好適に使用できる。ポリエチレンテレフタレートフィルム表面の濡れ性が３２ｍＮ／ｍ以上であれば、加熱プレス処理してできた積層板を研磨することなく、他のプリプレグや銅箔等を積層できる。上記条件でプレス処理をした後の、ポリエチレンテレフタレートフィルム表面の濡れ性が３２ｍＮ／ｍ未満であると、加熱プレス処理してできた積層板の表面濡れ性が悪くなり、他のプリプレグや銅箔等を積層した場合に密着性が低下する虞がある。
ここで、表面濡れ性の上限は特に制限されるものではないが、本試験方法においては、プレス処理を施す前のポリエチレンテレフタレートフィルムの表面濡れ性が上限となる。
【００１５】
また、具体的な滑り性の目安は、その離型剤塗布表面同士の静摩擦係数が０．１０〜０．５０の範囲にあることが望ましい。静摩擦係数が０．１０未満の場合には離型フィルム断裁後に離型フィルムを積重ねた時に崩れやすく、ピン穴を開ける際にも離型フィルムがずれやすく、結果的に穴がずれてしまう問題が発生する。また、ロール状態で熱プレス工程に供給される場合には、離型フィルムが巻ずれを生じやすくなる問題が発生する。一方、静摩擦係数が０．５０を越える場合には積重ねてある離型フィルムから離型フィルムを１枚とる場合にとりにくくなり、積層配線基板の製造時の熱プレス工程での作業性が悪くなる。また、ロール状態で熱プレス工程に供給される場合には離型フィルムを繰り出した時に静電気が発生し易く、作業環境中の塵や埃を吸着しやすくなる問題がある。
【００１６】
次に、特定シリコーン系離型剤の組成について説明する。この特定シリコーン系離型剤は、一般的なシリコーン系離型剤にセルロース誘導体を配合した混合物であることを特徴とする。
シリコーン系離型剤は、耐熱性および離型性が優れている点から用いられるもので、公知のシリコーン系離型剤であれば何れも本発明に使用し得る。シリコーン系離型剤としては、商品形態別にいえば無溶剤型、エマルジョン型、溶剤型の何れのシリコーン系離型剤でも使用し得る。また、反応形態別に言えば、加熱反応型（加熱付加反応型、加熱縮合反応型）、紫外線反応型、電子線反応型、熱と紫外線併用反応型の何れのシリコーン系離型剤でも使用し得る。ただし、ポリエステル系フィルムの両面に離型剤層を有する場合には、加熱縮合反応型を使用するとブロッキング現象が起こるため、他のシリコーン系離型剤がよい。
また、セルロース誘導体との混合し易さの観点からは、溶剤型、無溶剤型の順で好ましく、エマルジョン型はあまり適していない。
【００１７】
本発明に適用可能な市販のシリコーン系離型剤を具体的に挙げれば、信越化学工業社製の（以下、商品名）ＫＳ−７７０、ＫＳ−７７６Ａ、ＫＳ−８３８、ＫＳ−８５６、ＫＳ−７７０Ｌ、ＫＳ−７７６Ｌ、ＫＳ−８４７、ＫＳ−７０５Ｆ、ＫＳ−７０９、ＫＳ−７７９Ｈ、ＫＳ−８３７、ＫＳ−７７８、ＫＳ−８４３、ＫＳ−８３５、ＫＳ−７７５、ＫＳ−８３０、ＫＳ−８３０Ｅ、ＫＳ−８３９、ＫＳ−７７４、ＫＳ−８４１、ＫＳ−７１９、ＫＳ−７２３Ａ／Ｂ、ＫＳ−８８３、ＫＳ−７１８、ＫＳ−７０８Ａ、ＫＮＳ−３０３、ＫＮＳ−３０５、ＫＮＳ−３２０、ＫＮＳ−３１９、ＫＮＳ−３１６、ＫＮＳ−３１０、ＫＮＳ−５００３Ａ／Ｂ、ＫＮＳ−５１００、ＫＮＳ−５３００、ＫＭ−７６６、ＫＭ−７６８、ＫＭ−７６４、ＫＭ−７６５などがある。東レ・ダウコーニング・シリコーン社製の離型剤としては、ＳＲＸ２１１、ＳＤ７２２０、ＳＲＸ３４５、ＳＲＸ３５７、ＳＤ７２２７、ＳＲＸ３７０、ＳＤ７２２３、ＳＤ７２２６、ＳＤ７２２９、ＳＹＬ−ＯＦＦ２３、ＳＲＸ２４４、ＳＲＸ２９０、ＳＹＬ−ＯＦＦ２２、ＳＭ７２７０、ＳＭ７２７３、ＢＹ２４−４０３、ＢＹ２４−４０５、ＢＹ２４−４０７、ＳＰ７２４８、ＢＹ２４−４１３、ＳＰ−７２５９、ＢＹ２４−４１１、ＳＰ７２６８、ＢＹ２４−４２０、ＢＹ２４−４１２、ＢＹ２４−４１６、ＬＴＣシリーズなどが挙げられる。
【００１８】
ＧＥ東芝シリコーン製の離型剤としては、ＴＰＲ６５００、ＴＰＲ６５０１、ＵＶ９３００、ＵＶ９３１５、ＵＶ９４２５、ＸＳ５６−Ａ２７７５、ＸＳ５６−Ａ２９８２、ＵＶ９４３０、ＴＰＲ６６００、ＸＳ５６−Ｂ１７９４、ＳＬ６１００、ＴＰＲ６６０４、ＳＭ３０００、ＳＭ３２００、ＳＭ３０３０、ＴＰＲ６７０５、ＴＰＲ６７２２、ＴＰＲ６７２１、ＴＰＲ６７０２、ＴＰＲ６７００、ＸＳ５６−Ａ８０１２、ＴＰＲ６７０１、ＴＰＲ６７０７、ＴＰＲ６７０８、ＴＰＲ６７１０、ＴＰＲ６７１２、ＸＳ５６−Ａ３９６９、Ｘ５６−Ａ５７３０、ＸＳＲ７０２９、ＸＳ５６−Ａ３−７５、ＹＳＲ３０２２などが挙げられる。ダウコーニングアジア製の離型剤としては、ＤＫＱ３−２０２、２０３、２１０、２４０、３０５０などが挙げられる。
【００１９】
本発明はポリエステル系フィルムの少なくとも片面の離型剤が上記のようなシリコーン系離型剤とセルロース誘導体の混合物からなる離型剤を用いることを特徴としている。セルロース誘導体の種類は特に制限されるものではなく、種類や重合度については任意に選択すればよい。
具体的には、カルボキシメチルセルロース、メチルセルロース、エチルセルロース、エチルヒドロキシセルロース、アミノエチルセルロースなどが挙げられる。有機溶剤に可溶する点からエチルセルロースがより好適である。シリコーン系離型剤とセルロース誘導体の混合比率は、離型剤塗布表面と２軸延伸ポリエチレンテレフタレートフィルムを重ね合わせ、１８０℃、３０ａｔｍの条件で２０分プレス処理をしたのちの、ポリエチレンテレフタレートフィルム表面の濡れ性が３２ｍＮ／ｍ以上あれば、特に制約を受けるものではないが、通常はシリコーン系離型剤／セルロース誘導体の混合比率が固形分換算で１／１００〜１００／１程度である。
この混合比率は、組合せて用いられるシリコーン系離型剤とセルロース誘導体それぞれの特性に応じて、前記物性を考慮しながら、適宜、選択される。具体的には、セルロース誘導体の混合比率が向上するにつれて離型剤の移行抑制効果は向上するが、多すぎると離型性が低下する傾向がある。例えば、シリコーン系離型剤として汎用の溶剤型付加反応タイプのシリコーンとエチルセルロースの混合物の場合、両者の混合比率は固形分換算で、１００／３０〜１００／２００の範囲が好ましい。
【００２０】
セルロース誘導体は、通常、固体粉末状の形態を取っているが、本発明に使用する場合には、混合物を調製する際に、トルエン等の有機溶剤に溶解させて使用するか、もしくは溶剤タイプのシリコーン系離型剤に溶解させて使用するのが一般的である。セルロース誘導体を固体粉末状の形態のまま使用すると、均一混合が困難となり、シリコーン系離型剤において問題となるシリコーン系離型剤の移行や滑り性が抑えにくくなる。
【００２１】
離型フィルムはポリエステル系フィルムの片面のみに離型処理を施したものでも、両面に離型処理を施したものでもいずれでもよいが、複数の多層板を１度のプレス処理にて加熱プレスする際に、多層板の間に挟まれる離型フィルムの場合、両面に離型処理が必要なため、この場合には両面離型フィルムがよい。
従来の両面離型フィルムの場合、断裁時に表裏の区別がつきにくいことが問題となることがあるが、ポリエステル系フィルムの片面にシリコーン系離型剤を塗布し、反対面にシリコーン系とエチルセルロースの混合物からなる本発明の特定シリコーン系離型剤を塗布した離型フィルムを用いることで、表面の滑り性や濡れ性の違いから、表裏の判別が容易となるという利点をも有する。特に、シリコーン系剥離剤の移行が問題のない使用方法、例えば、積層配線基板を製造後に表面研磨工程があるものなど、に使用するのであれば、片面に一般的なシリコーン系離型剤を塗布し、反対面に本発明に係るシリコーン系離型剤とセルロース誘導体との混合物からなる離型剤を塗布した離型フィルムが望ましい。ここで、一般的なシリコーン系離型剤としては、前記特定シリコーン系離型剤を調整するための離型剤として挙げたものを同様に挙げることができる。
【００２２】
また、ポリエステル系フィルムの両面に離型剤層を有する場合には、少なくとも片面が本発明に係るシリコーン系離型剤とセルロース誘導体の混合物からなる離型剤を用いれば、反対面はシリコーン系離型剤に限らず公知の他の（シリコーン系以外の）離型剤を用いることもできる。
ここで用い得るシリコーン系以外の離型剤としては、具体的には、フッ素系離型剤、長鎖アルキル基含有離型剤、アルキッド樹脂系離型剤、アミノアルキッド樹脂系離型剤、有機ポリマーとシリコーンとの共重合もしくは混合の離型剤、セラック樹脂、ポリオレフィン系離型剤などが挙げられるが、通常は、剥離性、耐熱性の観点から一般的なシリコーン系離型剤を用いることが多い。
【００２３】
離型剤の塗布方法はグラビヤコート、メイヤーバーコート、エアーナイフコートなどの公知の方法により基材に離型剤を塗布した後、加熱処理や紫外線照射、電子線照射などの公知の方法で乾燥硬化し、離型剤層を形成する方法が適用できる。離型剤塗布時に基材と離型剤の密着性向上のために、基材表面にコロナ放電処理を行ったり、表面に易接着コート剤を塗布するなどの方法で、基材表面の濡れ性を改良したり、離型剤にシランカップリング剤などの密着性向上剤等を内添したりしてもよい。
離型剤層の厚みは、必要な離型効果を得られる限りにおいては特に制限はないが、適切な離型性を得る観点から０．０２〜１．０μｍ程度であることが好ましい。
【００２４】
このようにして得られる本発明の離型フィルムは、離型剤の移行が少なく、離型フィルムを断裁、積重ねたときに積重ねやすく、ピン穴を開ける際にも離型フィルムがずれにくい。また、離型フィルム積重ね品から離型フィルムを１枚ずつ取る際にも非常に取りやすく、安価な離型性フィルムが得られ、ロール状態で扱われた際にも、巻ずれが発生しにくく、且つ、繰り出し時の静電気の発生も少ない離型フィルムとなる。さらに、前記ポリエステル系フィルムを基材として用いた場合には、先に述べたような利点に加えて、耐熱性が良好な離型フィルムを得ることができる。
【００２５】
【実施例】
以下、実施例を挙げて本発明をさらに説明する。
［参考例１］
シリコーン系離型剤東レ・ダウコーニング・シリコーン製の固形分３０％の付加反応型離型剤ＳＲＸ−２１１（触媒ＳＲＸ−２１２をＳＲＸ−２１１１００重量部に対して１部添加）とエチルセルロース（ダウケミカル製エトセルＳＴＤ−１００）の１０％トルエン溶液を重量比で１／２（固形分比：１００／６７）となるように混合し、トルエン溶剤で希釈して離型剤溶液を作成する。
厚さ２５μｍの２軸延伸ポリエチレンテレフタレートフィルム（東洋紡績エステルＥ５０００）の片面に、この離型剤溶液を固形分として０．２ｇ／ｍ²となるように塗布した後、１４０℃の熱風循環式オーブン中で３０秒間加熱処理することにより乾燥硬化させて、片面に特定シリコーン系離型剤層を形成した。その後、この片面特定シリコーン系離型剤処理品のポリエチレンテレフタレートフィルム背面にも前記と同様にして特定シリコーン系離型剤を処理することにより、両面離型処理を施した離型フィルムＡを得た。
【００２６】
［参考例２］
前記参考例１で用いたシリコーン系離型剤とエチルセルロース１０％トルエン溶液との混合比が、重量比で１／４（固形分比：１００／１３３）となるように混合した以外は、参考例１と同様にして両面離型処理を施した離型フィルムＢを得た。
［実施例１］
前記参考例１で用いたシリコーン系離型剤とエチルセルロースの混合物からなる離型剤を塗布した片面特定シリコーン系離型剤処理品のポリエチレンテレフタレートフィルム背面に、参考例１で用いたシリコーン系離型剤のみを、固形分として０．２ｇ／ｍ²となるように塗布した以外は実施例１と同様にして両面離型処理を施した離型フィルムＣを得た。
［参考例３］
前記参考例１で用いたシリコーン系離型剤とエチルセルロースの混合物からなる離型剤を塗布した片面特定シリコーン系離型剤処理品のポリエチレンテレフタレートフィルム背面に、離型剤を塗布しない以外は参考例１と同様にして片面離型処理を施した離型フィルムＤを得た。
【００２７】
［比較例１］
実施例１で用いたシリコーン系離型剤のみを、固形分として０．２ｇ／ｍ²となるように塗布してシリコーン系離型剤処理を行なった以外は実施例１と同様にして両面離型処理を施した離型フィルムＥを得た。
［比較例２］
実施例１で用いたエチルセルロースのみを、固形分として０．２ｇ／ｍ²となるように塗布した以外は実施例１と同様にして両面離型処理を施した離型フィルムＦを得た。
【００２８】
［離型フィルムの評価法］
得られたサンプルの離型剤移行性、離型剤塗布表面の静摩擦係数、離型性、断裁品の積重ね性、熱プレス工程での作業性を次に記載する方法で評価を行った。結果を下記表１に示す。
（１．離型剤移行性）
前記シリコーン系離型剤とセルロース誘導体の混合物である離型剤を塗布されてなる離型剤塗布表面と、厚さ２５μｍの２軸延伸ポリエチレンテレフタレートフィルムを重ね合わせ、１８０℃、３０ａｔｍの条件で２０分プレス処理をしたのち、２軸延伸ポリエチレンテレフタレートフィルムを剥がし、フィルムの離型剤塗布表面と接していた部分の濡れ性をＪＩＳＫ６７６８に規定する方法で測定する。２軸延伸ポリエチレンテレフタレートフィルムの表面濡れ性が高い値ほど濡れ性が良好である。
【００２９】
（２．離型剤塗布表面の静摩擦係数）
ＪＩＳＫ−７１２５に規定する方法にて、離型剤塗布面同士（同一離型面同士）の静摩擦係数を測定する。（実施例１についてはシリコーン系離型剤とエチルセルロースの混合物からなる離型剤を塗布されてなる離型剤塗布面を測定）
（３．２層板の作成（離型性評価））
銅箔／プリプレグ／銅箔と積層したものを、実施例、参考例、及び、比較例で得られた離型フィルム２枚で挟み込み、この積層品を更にステンレス板２枚で挟み込む。プレス機にて１８０℃の条件下、５０ｋｇ／ｃｍ²のプレス圧にて３０分プレス処理を行い、プリプレグ樹脂の硬化を行い、２層板を作成する。冷却後、離型フィルムがステンレス板および２層板から容易に剥離できるかどうかを観察する。
【００３０】
（４．断裁品の積重ね性）
得られたサンプルを３０ｃｍ四方の大きさに断裁する。その後、断裁品を１００枚積重ねた後、積重ね品を手に持って穴あけ器に設置した際に積重ね品にずれが生じるかどうかを目視にて観察する。
（５．熱プレス工程での作業性）
得られたサンプルを３０ｃｍ四方の大きさに断裁する。その後、断裁品を１００枚積重ねた後、積重ね品を手に持って穴あけ器に設置して、直径２ｍｍの穴をサンプルの４角に開ける。その後、積重ね品から離型フィルムを手で１枚ずつ取ったときの取りやすさを測定する。
【００３１】
【表１】
【００３２】
表１の結果より、実施例１の本発明の離型フィルムは、離型剤移行性、離型性、断裁品の積重ね性、熱プレス工程での作業性が良好であったのに対して、比較例１の離型フィルムは離型性は良好であったが、離型剤の移行があり、離型面に合わせたポリエステルフィルムの表面濡れ性を大きく低下させた。また、断裁品の積重ね時にズレが発生した。このため、穴あけ工程で位置を揃えるのに多大な労力を必要とした。また、比較例２の離型フィルムは断裁品の積重ね性は良好であったが、離型性が不良でプレス時にはみ出したプリプレグの樹脂が剥がれなかった。また、積重ね品から離型フィルムを１枚ずつ取るときに、離型フィルムがほとんど滑らないため、簡単には取れなかった。このため熱プレス工程での作業性が悪化する結果となった。
【００３３】
【発明の効果】
本発明の離型フィルムは、加熱プレスした後のプリプレグや銅箔などの表面の濡れ性を低下させることなく、離型フィルムの断裁、積重ね、ピン穴の開口などの各工程において、離型フィルムがずれにくく、作業性に優れており、安価であり、さらに、ロール状態で扱われた際にも、巻きずれが発生しにくく、且つ、繰り出し時の静電気の発生も少ないという効果を奏する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a release film used in a prepreg press process at the time of manufacturing a conductive foil laminate, and in particular, relates to a release film suitably used for manufacturing a laminated wiring board widely used in electronic devices and the like. .
[0002]
[Prior art]
Conventionally, as a method of manufacturing a multilayer wiring board having a multilayer conductor circuit, a prepreg is laminated on an inner layer material having a conductor circuit on one side or both sides, and a conductor foil is disposed on the outermost layer, and then integrated by heat pressing. The method is common. In such a method, powders and other foreign matters generated from the prepreg are likely to enter the conductive foil, and this causes local pressure on the conductive foil, which may cause dents on the surface of the conductive foil. There is.
In order to prevent this problem, a method has been proposed in which a release film formed of a resin or the like is disposed between the conductor foil and the mirror plate to relieve local pressure due to foreign matter. The release film is cut into a predetermined size in advance, and is supplied to the manufacturing process of the laminated wiring board in a stacked state. In the production process of the laminated wiring board, the conductor foil or prepreg and the release film are laminated and heated and pressed, and the alignment of the conductor foil, prepreg and release film is necessary at the time of lamination. For this reason, the release film supplied to the manufacturing process of the laminated wiring board is generally provided with pin holes at several locations for alignment. The pin holes are not formed in each release film one by one, but usually, a method is used in which holes are formed at a time in a state of being cut and stacked.
[0003]
In the manufacturing process of a laminated wiring board, a release film and a prepreg cut to a predetermined size, a copper foil, and the like are laminated, and a laminated wiring board is created by hot pressing.
As such a release film, a film in which a release agent such as silicone is applied to one or both sides of a polyester film typified by a polyethylene terephthalate film, a fluorine film, a polyolefin film, or the like has been used. However, in a film in which a release agent such as silicone is applied to one side or both sides of a polyethylene terephthalate film, the component of the release agent at the time of hot pressing at the time of manufacturing the laminated wiring board is different from the prepreg that was in contact with the release film at the time of hot pressing. There existed a problem which transfers to surfaces, such as copper foil, and reduces surface wettability, such as a prepreg and copper foil.
When surface wettability of prepreg, copper foil, etc. is reduced, when laminating other prepreg, copper foil, etc. to the laminate obtained as it is, adhesion of the surface to which the release agent has transferred Because there is a concern that it will worsen, it requires a step of removing the transferred release agent by polishing the surface of the prepreg or copper foil that was in contact with the release film during hot pressing, and the workability is poor was there.
[0004]
In addition, a film in which a release agent such as silicone is applied to one or both sides of a conventional polyethylene terephthalate film is easy to use because it has good heat resistance and releasability in the hot press process during the production of laminated wiring boards. When the release film is cut to a predetermined size and stacked in the process before being supplied to the process, the release agent surface is slippery, so it slips when the release film is stacked and is difficult to stack There was also. In addition, even in the process of making pin holes in the release film trimming stacked product, if the release film is slippery, the position may be shifted during drilling.
On the other hand, there is a method in which the release film is not cut but is supplied to the hot press process in a roll state and continuously hot pressed by roll-to-roll. The wound release film is liable to cause winding misalignment, and care must be taken in handling the roll. When the winding misalignment occurs once, there is a problem that the press does not start in the hot press process.
[0005]
When using a fluorine-based film or a polyolefin-based film, although poor workability at the time of stacking due to such a release agent and problems of misalignment at the time of drilling are not seen, Due to its high cost, there is a problem that the manufacturing cost is high, and when a polyolefin film is used, the heat resistance of the polyolefin film itself is poor, so that it is used for a temperature of 120 ° C. or higher during pressing. There was a problem that could not be used.
[0006]
[Problems to be solved by the invention]
The present invention was made in order to solve the above-mentioned problems, and without releasing the wettability of the surface of the prepreg or copper foil after heat pressing, the release film was cut, stacked, and pinned. In each process such as opening of a hole and conveyance, the release film is less likely to be displaced, has excellent workability, and provides an inexpensive release film. Another object of the present invention is to provide a release film that is less likely to cause winding slippage and is less likely to generate static electricity during unwinding when handled in a roll state.
[0007]
[Means for Solving the Problems]
In examining the release agent with good surface wettability such as prepreg and copper foil after hot pressing, the present inventors further laminate other prepreg and copper foil on the obtained laminate. In some cases, the degree of transfer of the release agent was examined to reduce the adhesion of the prepreg resin. As a result, the inventors have found predetermined physical properties and additives for realizing the properties and completed the present invention.
[0008]
That is, the release film of the present invention is a release film containing a silicone release agent on both surfaces of a synthetic resin film and applied with release agents having different compositions from each other, and the release film applied to one surface. The mold release agent is a silicone release agent that does not contain a cellulose derivative, the release agent applied to the other surface is a mixture of a silicone release agent and a cellulose derivative, and the following condition (1) It has the physical property which satisfy | fills.
(1) A release agent which is a mixture of the silicone release agent and the cellulose derivative is applied. With release agent application surface , After the biaxially stretched polyethylene terephthalate film was overlaid and pressed for 20 minutes at 180 ° C. and 30 atm, the biaxially stretched polyethylene terephthalate film was peeled off, and the wettability of the part that was in contact with the release agent coating surface of the film was removed. The surface wettability is 32 mN / m or more when measured by the method defined in JIS K6768.
That is, the present inventor can superimpose a release agent-coated surface and a biaxially stretched polyethylene terephthalate film, and after heat-pressing under a predetermined condition, if the wettability of the polyethylene terephthalate film surface is 32 mN / m or more, The inventors have found that other prepregs, copper foils, and the like can be laminated without polishing the laminate produced by the heat press treatment, and have invented a release film using a release agent having such physical properties.
[0009]
In addition, the present invention In Of the synthetic resin film Of the release agents provided on both sides One side mold release agent A mixture of silicone release agent and cellulose derivative, The mold release agent by Processing table Face-to-face The physical friction coefficient is in the range of 0.10 to 0.50. But By satisfying this condition, it is possible to realize further improvement that the release films are easily stacked when stacked after the release film cutting, and that the release films are not easily displaced when the pin holes are opened. That is, if the static friction resistance of the release agent coating surface is not increased to some extent, the release film is likely to be misaligned after the release film is cut, and it may be disintegrated during the stacking or even when the pin hole is opened. Even when it is supplied to the hot press process in the state, winding slip is likely to occur, but if the static friction coefficient is too high, it becomes difficult to take one release film from the release films that are stacked, Workability in the hot press process at the time of manufacture deteriorates. For this reason, the range of the static friction coefficient between the release agent application | coating surfaces optimal was discovered. In addition, within this friction coefficient range, when used in a roll state, it is possible to suppress the generation of static electricity due to friction when the roll is fed out. Foreign matter can be prevented from entering the substrate. For this reason, when the static friction resistance of the release agent application surface is 0.10 or more and 0.50 or less, the workability in the cutting process or the hot press process is remarkably improved.
[0010]
Claims of the invention 2 The release film according to the present invention is a mixture of a silicone release agent and ethyl cellulose on one side of a synthetic resin film and a silicone release agent on the other side, and The coefficient of static friction of the treated surface of the mixture of silicone release agent and cellulose derivative is In the range of 0.10 to 0.50 Ruko And features.
The synthetic resin film is preferably a polyester film from the viewpoint of product cost and heat resistance. Both A film having a release agent such as silicone applied to the surface is suitable. However, when a release agent is applied to both surfaces, the release agent having improved surface wettability, which is an effect of the present invention. That is, a release agent comprising a mixture of a silicone release agent and a cellulose derivative May be applied to one side, and a conventional silicone release agent having excellent peelability and heat resistance may be used on the side that does not require improvement of wettability.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The release film of the present invention is a synthetic resin film as a substrate. Both sides In Contains silicone mold release agents and different compositions Release agent Respectively It is applied and a release agent layer is provided.
As the film used as the base material in the release film of the present invention, a film that has an appropriate elasticity at the time of hot pressing and can withstand heating is used among the synthetic resin films.
The synthetic resin film as the base material is not particularly limited as long as it satisfies the above points. Specifically, the polyolefin film, the polyester film, the polyamide film, the polyimide film, the polyphenylene Examples thereof include a sulfide film, a polyether ether ketone film, a vinyl chloride film, a vinylidene chloride film, a polyvinyl alcohol film, and a fluorine film.
A polyester film or a polyamide film is preferable from the viewpoint of heat resistance and cost, and a polyester resin film is more preferable from the viewpoint of dimensional stability during moisture absorption. The polyester resin film is preferably an aromatic polyester from the viewpoint of heat resistance. Specific examples of suitable materials for use in the present invention include polyethylene terephthalate film, polybutylene terephthalate film, polyethylene isophthalate film, polyethylene naphthalate film, polyethylene adipate film, polyethylene liquid crystal polymer film, and polyester thermosetting. Examples thereof include a resin and a mixed resin film of the above resins, and among them, a polyethylene terephthalate film and a polyethylene naphthalate film are particularly preferable from the viewpoint of heat resistance and cost.
[0012]
As the synthetic resin film, a film in which the synthetic resin is formed by a known method may be used. Further, any of unstretched, uniaxially stretched, and biaxially stretched may be used, but a biaxially stretched film is preferable from the viewpoint of heat resistance. The thickness of the film is not particularly limited, but is preferably about 25 to 125 μm from the viewpoint of heat resistance, mechanical strength, cost, and the like.
The film may be transparent, translucent, or colored, and may be coated with an antistatic agent as required. Moreover, you may use what gave the surface a corona treatment, an easily-adhesive coating, and a matting process.
[0013]
The release film of the present invention is obtained by applying a release agent to one side or both sides of the synthetic resin film. In the case of one side, the release agent is applied, and when applied to both sides, at least the release agent is applied. The release agent on one side is a release agent composed of a mixture of a silicone release agent and a cellulose derivative (hereinafter referred to as a specific silicone release agent as appropriate). By mixing the cellulose derivative with the silicone release agent, it is possible to suppress the silicone migration and the slipperiness of the release agent application surface, which are problems with the silicone release agent.
[0014]
First, preferable physical properties of the specific silicone release agent will be described.
A specific measure of the degree of release agent transfer is to wet the polyethylene terephthalate film surface after the release agent-coated surface and biaxially stretched polyethylene terephthalate film are overlaid and pressed for 20 minutes at 180 ° C. and 30 atm. Sex is 32mN / M If it exists, it can be used conveniently. If the wettability of the polyethylene terephthalate film surface is 32 mN / m or more, other prepregs, copper foils, and the like can be laminated without polishing a laminated plate formed by heat pressing. If the wettability of the surface of the polyethylene terephthalate film after press treatment under the above conditions is less than 32 mN / m, the surface wettability of the laminate produced by the heat press treatment will deteriorate, and other prepregs, copper foils, etc. When these layers are laminated, the adhesion may be reduced.
Here, the upper limit of the surface wettability is not particularly limited, but in this test method, the upper limit is the surface wettability of the polyethylene terephthalate film before the press treatment.
[0015]
Moreover, as a specific guideline for slipperiness, it is desirable that the static friction coefficient between the release agent application surfaces is in the range of 0.10 to 0.50. When the coefficient of static friction is less than 0.10, the release film is likely to collapse when the release films are stacked after cutting the release film, and the release film is likely to be displaced even when a pin hole is opened, resulting in a problem that the holes are displaced. appear. Moreover, when it supplies to a hot press process in a roll state, the problem which a mold release film tends to produce winding misalignment generate | occur | produces. On the other hand, when the static friction coefficient exceeds 0.50, it becomes difficult to take one release film from the release films that are stacked, and workability in the hot press process at the time of manufacturing the laminated wiring board is deteriorated. In addition, when supplied to the hot press process in a roll state, there is a problem that static electricity is easily generated when the release film is unwound, and dust and dirt in the work environment are easily adsorbed.
[0016]
Next, the composition of the specific silicone release agent will be described. This specific silicone release agent is a mixture in which a cellulose derivative is blended with a general silicone release agent.
The silicone release agent is used from the viewpoint of excellent heat resistance and release properties, and any known silicone release agent can be used in the present invention. As the silicone-based release agent, any solvent-free, emulsion-type, or solvent-type silicone release agent can be used depending on the product form. In addition, according to reaction type, any silicone release agent of heat reaction type (heat addition reaction type, heat condensation reaction type), ultraviolet reaction type, electron beam reaction type, heat and ultraviolet combined reaction type can be used. . However, when a release agent layer is provided on both sides of the polyester film, a blocking phenomenon occurs when the heat condensation reaction type is used, so other silicone release agents are preferable.
Further, from the viewpoint of easy mixing with the cellulose derivative, the solvent type and the solventless type are preferable in this order, and the emulsion type is not suitable.
[0017]
Specific examples of commercially available silicone release agents that can be applied to the present invention include KS-770, KS-776A, KS-838, KS-856, and KS- manufactured by Shin-Etsu Chemical Co., Ltd. (hereinafter, trade names). 770L, KS-776L, KS-847, KS-705F, KS-709, KS-779H, KS-837, KS-778, KS-843, KS-835, KS-775, KS-830, KS-830E, KS-839, KS-774, KS-841, KS-719, KS-723A / B, KS-883, KS-718, KS-708A, KNS-303, KNS-305, KNS-320, KNS-319, KNS-316, KNS-310, KNS-5003A / B, KNS-5100, KNS-5300, KM-766, KM-768, KM-764, K -765, and the like. As release agents manufactured by Toray Dow Corning Silicone, SRX211, SD7220, SRX345, SRX357, SD7227, SRX370, SD7223, SD7226, SD7229, SYL-OFF23, SRX244, SRX290, SYL-OFF22, SM7270, SM7273, BY24 -403, BY24-405, BY24-407, SP7248, BY24-413, SP-7259, BY24-411, SP7268, BY24-420, BY24-412, BY24-416, LTC series and the like.
[0018]
As release agents made of GE Toshiba Silicone, TPR6500, TPR6501, UV9300, UV9315, UV9425, XS56-A2775, XS56-A2982, UV9430, TPR6600, XS56-B1794, SL6100, TPR6604, SM3000, SM3200, SM3030, TPR6705, TPR675 , TPR6721, TPR6702, TPR6700, XS56-A8012, TPR6701, TPR6707, TPR6708, TPR6710, TPR6712, XS56-A3969, X56-A5730, XSR7029, XS56-A3-75, YSR3022. Examples of the release agent made by Dow Corning Asia include DK Q3-202, 203, 210, 240, 3050 and the like.
[0019]
The present invention is characterized in that a release agent composed of a mixture of a silicone release agent and a cellulose derivative as described above is used as the release agent on at least one side of the polyester film. The type of cellulose derivative is not particularly limited, and the type and degree of polymerization may be arbitrarily selected.
Specific examples include carboxymethyl cellulose, methyl cellulose, ethyl cellulose, ethyl hydroxy cellulose, aminoethyl cellulose, and the like. Ethyl cellulose is more preferable from the viewpoint of being soluble in an organic solvent. The mixing ratio of the silicone-based release agent and the cellulose derivative is such that the release agent-coated surface and the biaxially stretched polyethylene terephthalate film are overlapped and pressed at 180 ° C. and 30 atm for 20 minutes. If the wettability is 32 mN / m or more, there is no particular limitation, but usually, the mixing ratio of silicone release agent / cellulose derivative is about 1/100 to 100/1 in terms of solid content.
This mixing ratio is appropriately selected in consideration of the physical properties in accordance with the characteristics of the silicone release agent and cellulose derivative used in combination. Specifically, the effect of suppressing the migration of the release agent is improved as the mixing ratio of the cellulose derivative is improved. However, if the mixing ratio is too large, the release property tends to be lowered. For example, in the case of a general solvent type addition reaction type silicone and ethyl cellulose mixture as the silicone release agent, the mixing ratio of both is preferably in the range of 100/30 to 100/200 in terms of solid content.
[0020]
The cellulose derivative is usually in the form of a solid powder, but when used in the present invention, it is used by dissolving it in an organic solvent such as toluene when preparing the mixture, or of the solvent type. In general, it is used by dissolving in a silicone release agent. If the cellulose derivative is used in the form of a solid powder, uniform mixing becomes difficult, and it becomes difficult to suppress the migration and slipperiness of the silicone release agent, which is a problem in the silicone release agent.
[0021]
The release film may be either one having a release treatment applied to only one side of a polyester film or one having both sides subjected to a release treatment, but a plurality of multilayer plates are heated and pressed by a single press process. In this case, in the case of a release film sandwiched between multilayer boards, a release treatment is required on both sides, and in this case, a double-sided release film is preferable.
In the case of a conventional double-sided release film, there is a problem that it is difficult to distinguish between the front and the back at the time of cutting. However, a silicone-type release agent is applied to one side of a polyester-type film, and silicone-type and ethylcellulose are applied to the opposite side. By using a release film coated with the specific silicone release agent of the present invention made of a mixture, there is also an advantage that the front and back sides can be easily distinguished from each other due to differences in surface slipperiness and wettability. In particular, when using for a usage method that does not cause a problem of migration of the silicone-based release agent, for example, one having a surface polishing step after manufacturing a multilayer wiring board, a general silicone-based release agent is applied on one side. And the release film which apply | coated the release agent which consists of a mixture of the silicone type release agent and cellulose derivative which concerns on this invention on the opposite surface is desirable. Here, as a general silicone mold release agent, those mentioned as the mold release agent for adjusting the specific silicone mold release agent can be similarly mentioned.
[0022]
In addition, when the release film is provided on both sides of the polyester film, if the release agent comprising a mixture of the silicone release agent and the cellulose derivative according to the present invention is used on at least one side, the opposite side is provided with the silicone release agent. Not only the mold agent but also other known release agents (other than silicone type) can be used.
Specific examples of release agents other than silicone-based release agents that can be used here include fluorine-based release agents, long-chain alkyl group-containing release agents, alkyd resin-based release agents, aminoalkyd resin-based release agents, organic Examples include release agents for copolymerization or mixing of polymers and silicones, shellac resins, polyolefin release agents, etc., but usually use general silicone release agents from the viewpoint of releasability and heat resistance. There are many.
[0023]
After applying the release agent to the substrate by a known method such as gravure coating, Mayer bar coating, air knife coating, etc., the release agent is dried by a known method such as heat treatment, ultraviolet irradiation, or electron beam irradiation. A method of curing and forming a release agent layer can be applied. In order to improve the adhesion between the base material and the release agent during the application of the release agent, the wettability of the base material surface can be improved by performing corona discharge treatment on the surface of the base material or applying an easy-adhesive coating agent to the surface Or an adhesion improver such as a silane coupling agent may be internally added to the release agent.
The thickness of the release agent layer is not particularly limited as long as a necessary release effect can be obtained, but is preferably about 0.02 to 1.0 μm from the viewpoint of obtaining appropriate release properties.
[0024]
The release film of the present invention thus obtained has little migration of the release agent, is easy to stack when the release film is cut and stacked, and the release film is not easily displaced when a pin hole is opened. In addition, it is very easy to remove the release films one by one from the release film stack, and an inexpensive release film can be obtained. In addition, the release film is less likely to generate static electricity during feeding. Further, when the polyester film is used as a substrate, a release film having good heat resistance can be obtained in addition to the advantages described above.
[0025]
【Example】
Hereinafter, the present invention will be further described with reference to examples.
[ Reference example 1]
Silicone release agent Toray Dow Corning Silicone's 30% solids addition reaction release agent SRX-211 (1 part of catalyst SRX-212 added to 100 parts by weight of SRX-211) and ethyl cellulose (Dow A 10% toluene solution of Chemical Etosel STD-100) is mixed to a weight ratio of 1/2 (solid content ratio: 100/67) and diluted with a toluene solvent to prepare a release agent solution.
On one side of a biaxially stretched polyethylene terephthalate film (Toyobo Ester E5000) having a thickness of 25 μm, 0.2 g / m of this release agent solution as a solid content. ² Then, it was dried and cured by heat treatment in a hot air circulation oven at 140 ° C. for 30 seconds to form a specific silicone release agent layer on one side. Thereafter, the back surface of the polyethylene terephthalate film of the one-side specific silicone-based release agent-treated product was treated with the specific silicone-based release agent in the same manner as described above to obtain a release film A subjected to double-sided release treatment. .
[0026]
[ Reference example 2]
Said Reference example Except for mixing so that the mixing ratio of the silicone-based mold release agent used in 1 and the ethylcellulose 10% toluene solution is 1/4 (solid content ratio: 100/133) by weight, Reference example The release film B which gave the double-sided release process like 1 was obtained.
[Example 1 ]
Said Reference example On the back of the polyethylene terephthalate film of the one-side specific silicone release agent-treated product coated with a release agent comprising a mixture of the silicone release agent and ethyl cellulose used in 1. Reference example Only the silicone release agent used in No. 1 was 0.2 g / m as a solid content. ² A release film C subjected to a double-sided release treatment was obtained in the same manner as in Example 1 except that the coating was applied in the same manner as in Example 1.
[ Reference example 3 ]
Said Reference example 1 except that the release agent is not applied to the back surface of the polyethylene terephthalate film of the one-side specific silicone release agent-treated product to which the release agent comprising a mixture of the silicone release agent and ethyl cellulose used in 1 is applied. Reference example In the same manner as in Example 1, a release film D subjected to single-sided release treatment was obtained.
[0027]
[Comparative Example 1]
Only the silicone release agent used in Example 1 was 0.2 g / m as a solid content. ² A release film E subjected to double-sided release treatment was obtained in the same manner as in Example 1 except that the coating was performed so that
[Comparative Example 2]
Only ethyl cellulose used in Example 1 was 0.2 g / m as a solid content. ² A release film F subjected to double-sided release treatment was obtained in the same manner as in Example 1 except that the coating was applied in the same manner as in Example 1.
[0028]
[Evaluation method of release film]
The release agent transferability of the obtained sample, the static friction coefficient of the release agent coating surface, the release property, the stackability of cut products, and the workability in the hot press process were evaluated by the methods described below. The results are shown in Table 1 below.
(1. Release agent transferability)
A release agent which is a mixture of the silicone release agent and the cellulose derivative is applied. With release agent application surface , The part where the biaxially stretched polyethylene terephthalate film with a thickness of 25 μm was overlapped and pressed for 20 minutes under the conditions of 180 ° C. and 30 atm, and then the biaxially stretched polyethylene terephthalate film was peeled off and the film was in contact with the release agent coating surface The wettability is measured by the method specified in JIS K6768. The higher the surface wettability of the biaxially stretched polyethylene terephthalate film, the better the wettability.
[0029]
(2. Static friction coefficient of the surface where the release agent is applied)
The static friction coefficient between the release agent application surfaces (same release surfaces) is measured by the method specified in JIS K-7125. (Example 1 Consists of a mixture of silicone release agent and ethyl cellulose It is applied with a release agent Measure the release agent application surface)
(3.2 Preparation of two-layer board (release property evaluation))
Examples of laminates of copper foil / prepreg / copper foil, Reference examples and The laminate is sandwiched between two release films obtained in the comparative examples, and the laminate is further sandwiched between two stainless plates. 50 kg / cm under the condition of 180 ° C in the press ² Press for 30 minutes at the press pressure to cure the prepreg resin. , Create a two-layer board. After cooling, observe whether the release film can be easily peeled off from the stainless steel plate and the two-layer plate.
[0030]
(4. Stackability of cut products)
The obtained sample is cut into a size of 30 cm square. Thereafter, after stacking 100 sheets of cut products, it is visually observed whether or not the stacked products are displaced when the stacked products are held in a hand and installed in a punch.
(5. Workability in the hot press process)
The obtained sample is cut into a size of 30 cm square. Then, after stacking 100 pieces of cut products, the stacked products are held in a hand and placed in a punch, and holes with a diameter of 2 mm are formed in four corners of the sample. Thereafter, the ease of removal when the release films are taken one by one from the stacked product by hand is measured.
[0031]
[Table 1]
[0032]
From the results in Table 1, the examples 1's The release film of the present invention was excellent in release agent transferability, release property, stackability of cut products, and workability in the hot press process, whereas the release film of Comparative Example 1 was released. Although the moldability was good, there was migration of the release agent, and the surface wettability of the polyester film matched to the release surface was greatly reduced. In addition, deviation occurred when the cut products were stacked. For this reason, a great deal of labor was required to align the positions in the drilling process. Further, the release film of Comparative Example 2 had good stackability of the cut product, but the release property was poor and the resin of the prepreg that protruded during pressing was not peeled off. In addition, when the release films were taken one by one from the stacked product, the release films hardly slipped, so it was not easy to remove. For this reason, the workability in the hot press process was deteriorated.
[0033]
【The invention's effect】
The release film of the present invention is a release film in each process such as cutting of a release film, stacking, opening of a pin hole, etc. without reducing the wettability of the surface of a prepreg or copper foil after hot pressing. It is less likely to slip, is excellent in workability, is inexpensive, and is less likely to cause winding slippage when it is handled in a roll state, and produces less static electricity during unwinding.

Claims

A release film used in a prepreg press process for producing a conductive foil laminate, comprising a silicone-based release agent on both surfaces of a synthetic resin film and coated with release agents having different compositions. The release agent applied to the silicone release agent does not contain a cellulose derivative, the release agent applied to the other surface is a mixture of a silicone release agent and a cellulose derivative, and A release film having physical properties satisfying the condition (1).
(1) A release agent application surface formed by applying a release agent that is a mixture of the silicone-based release agent and a cellulose derivative, and a biaxially stretched polyethylene terephthalate film are overlaid, and the conditions are 180 ° C. and 30 atm for 20 minutes. After the press treatment, the biaxially stretched polyethylene terephthalate film was peeled off, and when the wettability of the portion in contact with the release agent-coated surface of the film was measured by the method specified in JIS K6768, the surface wettability was 32 mN / m or more.

2. The release film according to claim 1, wherein the static friction coefficient between the treated surfaces of the release agent comprising a mixture of the silicone release agent and the cellulose derivative is in the range of 0.10 to 0.50 or less.

The mixing ratio of the silicone-based mold release agent and ethyl cellulose in the mixture of the silicone-based mold release agent and ethyl cellulose is in the range of 100/30 to 100/200 in solid content ratio. Release film.

The mixing ratio of the silicone mold release agent and ethyl cellulose in the mixture of the silicone mold release agent and ethyl cellulose is in a range of 100/67 to 100/133 in solid content ratio. Release film.