JP3606416B2 - Magnetic recording medium manufacturing method and manufacturing apparatus thereof - Google Patents

Description

（但し、ｎは重合度を示し、任意の自然数である。）
で表されるフッ素樹脂であり、例えば、テフロンＰＦＡ（ＤｕＰｏｎｔ社製）、テフロンＰＦＡ−Ｊ（三井デュポン社製）等が挙げられる。本発明において、前記潤滑剤層（パーフルオロポリエーテル層）の厚みは１〜５ｎｍであることが好ましい。
【００４７】
また、本発明の製造方法及び本発明の製造装置において、硬質炭素膜をプラズマＣＶＤ法によって形成することが好ましい。
【００４８】
一般に、硬質炭素膜（ＤＬＣ膜）の形成方法としては、スパッタリング法、ＣＶＤ法（Ｃｈｍｉｃａｌ Ｖａｐｏｒ Ｄｅｐｏｓｉｔｉｏｎ：化学的気相成長法）が用いられている。
【００４９】
特にＣＶＤ法は、成膜速度が比較的速い上、優れた質の膜を形成することが十分に可能である。
【００５０】
本発明の製造方法においては、金属磁性薄膜からなる磁性層を設けた非磁性支持体を搬送しながら、硬質炭素膜の形成と、フッ化処理膜の形成と、プラズマ中での処理とを順次行うことができる。
【００５１】
このように一連の工程で、硬質炭素膜の形成と、フッ化処理膜の形成と、プラズマ中での処理とを行うことができ、生産性、経済性等に優れた方法である。
【００５２】
また、本発明の製造装置においては、第１反応室と第２反応室とプラズマ処理室とが共通の真空槽内に配置されていることが好ましい。但し、各々の室が同一の真空槽内に配置されることに限定されるものではない。
【００５３】
更に、本発明の製造装置においては、第１反応室での硬質炭素膜の形成と、第２反応室でのフッ化処理膜の形成と、プラズマ処理室での処理とを順次行うように構成することができる。
【００５４】
このような構成の製造装置であると、製造装置内のスペースを有効に活用でき、生産性、経済性に優れた製造装置となる。
【００５５】
次に、本発明の製造装置の一例の構成について、図１を参照しながら説明する。
【００５６】
図１に示した製造装置は、非磁性支持体上に金属磁性薄膜の設けられた磁気記録媒体上に、硬質炭素膜、フッ化処理膜を順次設け、更に前記フッ化処理面をプラズマ処理することができる、磁気記録媒体の製造装置である。
【００５７】
この製造装置においては、金属磁性薄膜を設けた原反フィルム２１を磁気記録媒体用として処理するが、このフィルムは、ポリエチレンテレフタレート（ＰＥＴ）からなる非磁性支持体フィルム上に酸素ガスを導入しながらコバルト（Ｃｏ）を蒸着して部分酸化強磁性金属薄膜を形成したものである。このフィルム２１は、回転支持体（ガイドローラー）２０に支えられ所定のテンションが加えられながら、巻き出しロール１８、対向電極５、第１反応室２、第２反応室３、プラズマ処理室４、巻き取りロール１９の順に搬送される。
【００５８】
第１反応室２は硬質炭素膜の成膜用、フッ化処理室（第２反応室）３は硬質炭素膜のフッ化処理用、プラズマ処理室４はフッ化処理膜のプラズマ処理用としてそれぞれ設けられ、各々の室は共通の真空槽１の内部に配されており、図示しない真空排気装置により、真空槽１の内部は真空状態になされている。
【００５９】
第１反応室２の内部には電極７が組み込まれており、電極７には直流電源８により＋５００〜２０００Ｖの電位が印加される。この電極７としては、ガス（プラズマ化された原料ガス）を通しやすく、かつ反応室内で電界を均一に生じさせることができ、柔軟性に富む、例えば金網のような金属メッシュ電極であることが好ましい。この電極７の材料は銅が代表的であるが、導電性の点から金なども挙げられる。また、第２反応室と同様に、反応室の壁はガラス、樹脂及びセラミックス等の線膨張係数の小さい絶縁物からなることが望ましい。６は原料ガス導入口であり、例えばトルエン等の炭化水素を主成分とした原料ガス１５がここから導入される。
【００６０】
また、第１反応室と同様に、第２反応室（フッ化処理室）３の内部には電極９が組み込まれており、電極９には直流電源１１により適当な電位が印加される。電極９の形状、材質等は上記の電極７と同様である。また１０は原料ガス導入口であり、例えばエチレン等の原料ガス１６がここから導入される。
【００６１】
更に、プラズマ処理室４には、電極１４と対向電極１３とが設けられており、交流電源２２から電極１４へ所定の電圧が印加されるようになされている。但し、上述したように、この電極１４及び対向電極１３には直流電圧を印加することもできるし、処理室の外周に励起コイルを巻回して高周波電力を供給することもできる。２２はプラズマ処理用ガス１７の導入口であり、窒素、酸素、アルゴン等のガスがここから導入される。但し、これらのプラズマ処理用ガス１７は、導入後に閉じ込められたままで、プラズマ処理を行ってもよい。
【００６２】
また、第１反応室２、第２反応室３及びプラズマ処理室４と、その外周囲との間には、真空槽１に設けた図示しない真空排気装置により大きな圧力差が設けられており、反応に供されなかったガス（例えば、原料ガスそのもの、分解ガス、キャリヤーガス等）は、第１反応室２、第２反応室３と対向電極５との間のギャップ２４及び２５、更に、プラズマ処理室４の媒体搬送口２６から、逆流せずに排気される。
【００６３】
こうしてプラズマ処理されたフィルムは、巻き取り後に再び繰り出し、プラズマ処理による活性化状態を保持したままプラズマ処理面にフッ素含有潤滑剤をロール塗布など（図示せず）によって付着させる。
【００６４】
本発明の製造方法及び本発明の製造装置は、非磁性支持体上に磁気記録層（磁性層）が設けられ、更にその上に硬質炭素保護膜が設けられる磁気記録媒体（テープ、ディスク等）全てが対象となるが、特に、耐環境特性が厳しく要求されるテープ媒体について効果が大きい。
【００６５】
次に、本発明の製造方法及び本発明の製造装置によって作製された磁気記録媒体の一構造例を図２に示す。
【００６６】
非磁性支持体３２上に金属磁性薄膜３３が設けられている磁気記録媒体３１において、この表面上に硬質炭素膜３４が配され、この硬質炭素膜３４の表面にフッ化処理膜３５を設け、フッ化処理膜３５上の面３９にプラズマ処理を施し、その上にフッ素含有潤滑剤層３６を設けたものである。但し、本発明の製造方法及び本発明の製造装置によって作製される磁気記録媒体は、この構造の磁気記録媒体に限定されるものではない。
【００６７】
上記非磁性支持体上には、強磁性金属材料を直接被着することにより、金属磁性薄膜が磁性層として形成されているが、この金属磁性材料としては、通常の蒸着テープ等に使用されるものであれば如何なるものであってもよい。
【００６８】
例示すれば、Ｆｅ、Ｃｏ、Ｎｉ等の強磁性金属やＦｅ−Ｃｏ、Ｃｏ−Ｎｉ、Ｆｅ−Ｃｏ−Ｎｉ、Ｆｅ−Ｃｕ、Ｃｏ−Ｃｕ、Ｃｏ−Ａｕ、Ｃｏ−Ｐｔ、Ｍｎ−Ｂｉ、Ｍｎ−Ａｌ、Ｆｅ−Ｃｒ、Ｃｏ−Ｃｒ、Ｎｉ−Ｃｒ、Ｆｅ−Ｃｏ−Ｃｒ、Ｃｏ−Ｎｉ−Ｃｒ、Ｆｅ−Ｃｏ−Ｎｉ−Ｃｒ、等の強磁性合金が例示される。これらは、単層膜であっても、多層膜であっても良い。金属磁性薄膜の厚みは通常、０．０２〜１μｍである。
【００６９】
更には、非磁性支持体と金属磁性薄膜間、あるいは多層膜の場合には、各層間の付着力向上及び保磁力の制御のため、下地層又は中間層を設けてもよい。
【００７０】
金属磁性薄膜の形成手段としては、真空下で強磁性材料を加熱蒸発させ、非磁性支持体上に沈着させる真空蒸着法や、強磁性材料の蒸発を放電中で行うイオンプレーティング法、アルゴンを主成分とする雰囲気中でグロー放電を起こし、生じたアルゴンイオンでターゲット表面の原子を叩き出すスパッタリング法等、いわゆるＰＶＤ技術を使用してもよい。
【００７１】
勿論、本発明の磁気記録媒体（特に磁気テープ）の構成はこれに限定されるものではなく、本発明の要旨を逸脱しない範囲での変形、例えば、図２の一点鎖線の如くにバックコ−ト層３７を形成したり、非磁性支持体上に下塗り層を形成したり潤滑剤等の層（但し、図２の潤滑剤層３６と異なる。）を形成することは何ら差し支えない。また、非磁性支持体や、バックコ−ト層に含まれる非磁性顔料、樹脂結合剤、或いは潤滑剤に含まれる材料等は従来公知のものがいずれも使用できる。
【００７２】
【実施例】
以下、本発明を具体的な実施例について詳細に説明する。
【００７３】
本実施例は、金属磁性薄膜からなる磁性層を非磁性支持体上に有する磁気記録媒体（特に磁気テープ）に関するものであり、その作製条件を以下に示す。
【００７４】
蒸着テープ（原反）の作製条件；
非磁性支持体：厚さ１０μｍのポリエチレンテレフタレート（ＰＥＴ）
磁性層：厚さ２００ｎｍ、組成：Ｃｏ８０％−Ｎｉ２０％合金の単層膜
入射角：４５°〜９０°
導入ガス：酸素ガス
蒸着時真空度：２×１０^−２Ｐａ
【００７５】
次に、図１に示した製造装置を用いて、硬質炭素膜（ＤＬＣ膜）の成膜、フッ化処理膜（ポリテトラフルオロエチレン（ＰＴＦＥ）膜）の成膜、プラズマ処理を行った。各成膜条件は次の通りである。
【００７６】
ＤＬＣ膜の成膜条件；
原料ガス：トルエン
反応圧力：１０Ｐａ
導入電力：ＤＣ２．０ｋＶ
膜厚：８ｎｍ
【００７７】
ＰＴＦＥ膜の成膜条件
原料ガス：テトラフルオロエチレン（Ｃ_２ Ｆ_４ ）
反応圧力：２０Ｐａ
導入電力：ＤＣ１．０ｋＶ
膜厚：３〜４ｎｍ
【００７８】
但し、例９（比較例３）は、ＤＬＣ膜の成膜後、ＰＴＦＥ膜を成膜せずに直接に潤滑剤を塗布したサンプルテープである。また、例１０（比較例４）は、ＤＬＣ膜上にＰＴＦＥ膜の成膜後、プラズマ処理を施さないで直接に潤滑剤を塗布したサンプルテープである。
【００７９】
次に、例１〜８（但し、例５は比較例１、例８は比較例２）について、下記の表１に示す条件でＤＬＣ膜上のＰＴＦＥ膜のプラズマ処理を行った。また、下記の表１中、表面自由エネルギーは潤滑剤層を形成する前の値であり、その測定法は上述した。
【００８０】
次いで、非磁性支持体における磁性層が形成された面とは反対側の面に、カーボンとウレタン樹脂とからなるバックコ−ト層を０．６μｍ厚に塗布すると共に、上記プラズマ処理面に活性化状態の保持中にパーフルオロポリエーテル（ＰＦＰＥ）からなる潤滑剤を２μｍ厚に塗布し、しかる後、この原反を８ｍｍ幅に裁断し、磁気テープを作製した。
【００８１】
次に、上記例１〜１０のサンプルテープについて、動摩擦係数、スチル耐久性、シャトル耐久性、飽和磁化変化量についての評価を行った。
【００８２】
動摩擦係数：温度４０℃、湿度８０％の環境下での１００パス後の動摩擦係数を測定した。
【００８３】
スチル耐久性：温度−５℃において再生出力値が初期値から３ｄＢ下がるまでの時間（分）を示した。この測定にはソニー社製の８ｍｍビデオデッキ「ＥＶＯ９５００」を使用した。
【００８４】
シャトル耐久性：温度４０℃、湿度２０％の環境下にて、１００パス後の再生出力値の初期値に対する劣化量（ｄＢ）を測定した。この測定にはソニー社製の８ｍｍビデオデッキ「ＥＶＯ９５００」を使用した。
【００８５】
耐蝕性試験：温度３０℃、相対湿度７０％に維持された恒温槽中に、更に０．５ｐｐｍ濃度のＳＯ₂ガスを導入して、サビを発生させやすくする等、通常の状態よりも極めて厳しい環境に設定し、この環境に例１〜１０のサンプルテープを３日間保存するという耐環境試験（耐蝕性試験）を行った。ここでは、保存前と保存後の飽和磁化の変化量を測定しており、次の式（１）による評価を行った。
【００８６】
ΔＭｓ＝〔Ｍｓ’（保存後）−Ｍｓ（保存前）〕／Ｍｓ（保存前）…式（１）
（但し、ΔＭｓは飽和磁化の変化量（％）を示す。）
【００８７】
例１〜１０のサンプルテープについて、各プラズマ処理条件、表面自由エネルギー、及び評価項目についての測定結果を下記の表１に示す。
【００８８】

【００８９】

【００９０】
＜結果＞
本発明に基づく例１〜４、６及び７のように、パーフルオロポリエーテルからなる潤滑剤層の成膜前に、窒素、アンモニア、酸素、アルゴン等のガスを用いて、ポリテトラフルオロエチレンからなるフッ化処理膜面をプラズマ（ボンバード）処理してその表面自由エネルギーを３０〜４５ｍＪ／ｍ ² としたサンプルテープは、スチル耐久性及びシャトル耐久性が向上している。これは、プラズマ処理することで、前記表面に潤滑剤が吸着（付着）し易くなっているため、潤滑剤の特性が十分にかつ長時間にわたって引き出されているものと思われる。しかも、保存特性も大幅に良くなり、耐久性と共に耐蝕性も同時に向上させることができる。
【００９１】
また、例９は、フッ化処理膜を設けず、ＤＬＣ膜の表面に直接に潤滑剤を塗布せしめたサンプルテープであり、飽和磁化の変化量が非常に大きく、即ち経時劣化が激しいので、耐環境性（耐蝕性）に劣るサンプルテープであると言える。
【００９２】
また、例１０は、プラズマ処理を施さず、ＤＬＣ膜上にフッ化処理膜と潤滑剤とが順次設けられたサンプルテープである。フッ化処理膜が設けられているので耐蝕性には優れるものの、プラズマ処理が施されていないので、表面自由エネルギーが小さすぎ、潤滑剤が脱離し易く、耐久性に劣るサンプルテープであると言える。
【００９３】
また、例１〜４のサンプルテープのように、プラズマ処理に使用するガスは上述の窒素原子含有ガス、酸素原子含有ガス及び不活性ガス等のガスをいずれも使用できることがわかる。
【００９４】
更に、例１〜４、６及び７と、例５、８及び９〜１０との比較より、フッ化処理膜面の表面自由エネルギーは３０ｍＪ／ｍ²以上であると潤滑剤が吸着（付着）し易く、前記潤滑剤の特性が十分に引き出され、また、この表面自由エネルギーは４５ｍＪ／ｍ² 以下であると飽和磁化の変化又は経時劣化がかなり小さくなることがわかる。
【００９５】
このように、本発明に基づいてフッ化処理された硬質炭素膜表面を、更にプラズマ処理することにより、硬質炭素膜表面を活性化し、潤滑剤の吸着を促すことになり、前記潤滑剤を十分量かつ長時間吸着せしめ、前記潤滑剤の特性を十分に引き出すことができ、耐蝕性と耐久性とを同時に向上させることができる。従って、磁気記録媒体自体の信頼性が向上し、長期保存の必要性のあるデータストリーマーやビデオライブラリー等の特別な用途にも耐えうる磁気記録媒体の提供が可能になる。
【００９６】
以上、本発明を実施例について説明したが、本実施例は本発明の技術的思想に基づいて更に変形が可能である。
【００９７】
例えば、フッ化処理膜として、エチレンを原料ガスとしＣＶＤ法によって形成されたポリテトラフルオロエチレン膜を示したが、例えばポリテトラフルオロエチレン（ＰＴＦＥ）を塗布法によって形成してもよい。フッ化処理膜の材質は、他のフッ素樹脂であってよい。
【００９８】
また、プラズマ処理室は、直流電源、交流電源、高周波電源を用いたいずれの放電方法であってもよく、プラズマの励起方法としては、熱電子放電型、２極放電型、磁場収束型（マグネトロン放電型）、無電極放電型、ＥＣＲ放電型等の様々な方法が使用可能である。
【００９９】
また、フッ素含有潤滑剤としては、パーフルオロポリエーテル以外の他のフッ素含有潤滑剤を用いてもよい。
【０１００】
また、プラズマ処理室は真空槽の外部に設けられていてもよい。更に、上述の例ではプラズマ処理後に巻き取りロールに巻き取り、このロールから巻き出しながらフッ素含有潤滑剤を塗布したが、そのように巻き取らずに、フッ化処理膜面のプラズマ処理直後にフッ素含有潤滑剤を塗布してもよい。これは上述の真空槽内に別途配された塗布部にて行うことができる。
【０１０１】
更に、図２に示した本実施例による磁気記録媒体において、磁性層３３と硬質炭素膜３４との間にフッ化処理膜が設けられた構造の磁気記録媒体であってもよい。即ち、金属磁性薄膜からなる磁性層上に、順に、第１のフッ化処理膜、硬質炭素膜、第２のフッ化処理膜を設け、更に前記第２のフッ化処理膜面にプラズマ処理を施して最表面に潤滑剤層を設けてもよい。このような構成の磁気記録媒体を作製するに際し、図１に示した製造装置において、第１反応室２の前位に第２反応室３と同様の構成の反応室を設け、この反応室で前記第１のフッ化処理膜を形成することもできる。
【０１０２】
【発明の作用効果】
本発明の製造方法及びその装置によれば、金属磁性薄膜からなる磁性層上に硬質炭素膜を形成し、前記硬質炭素膜上にフッ化処理膜を形成し、前記フッ化処理膜をプラズマ中（例えば、窒素分子、酸素分子、アルゴン原子等のプラズマ）で処理し、この処理表面上にフッ素原子含有潤滑剤層（例えばパーフルオロポリエーテルの潤滑剤層）を設け、
前記プラズマ中でのボンバード処理により、前記フッ化処理膜の表面を清浄化すると 共に官能基を発現せしめて前記フッ化処理膜の表面自由エネルギーを３０ｍＪ／ｍ ² 以 上、４５ｍＪ／ｍ ² 以下とし、
前記ボンバード処理後に、前記フッ化処理膜の処理表面が活性化状態のうちに前記フ ッ素原子含有潤滑剤層を設ける
ので、金属磁性薄膜からなる磁性層の表面保護膜である硬質炭素膜上に、耐蝕性等に優れた前記フッ化処理膜（例えばポリテトラフルオロエチレン膜）を設け、更に、この表面上に、摺動耐久性等の厳しい状況の中でも十分量かつ長時間存在できる前記フッ素原子含有潤滑剤層を強固な付着力で設けることができる。
【図面の簡単な説明】
【図１】本発明の磁気記録媒体の製造装置の一例の要部構成図である。
【図２】同、製造装置を用いて製造された磁気記録媒体の概略断面図である。
【符号の説明】
１…真空槽、２…第１反応室、３…第２反応室、４…プラズマ処理室、
５…対向電極、６、１０、２３…ガス導入口、
７、９、１３、１４…電極、８、１１…直流電源、
１５、１６、１７…原料ガス、１８…巻き出しロール、
１９…巻き取りロール、２０…回転支持体（ガイドローラー）、
２１、３１…磁気記録媒体用の原反フィルム又は磁気記録媒体、
２２…交流電源、２６…搬送口、３２…非磁性支持体、３３…磁性層、
３４…硬質炭素膜、３５フッ化処理膜、３６…潤滑剤層、
３７…バックコ−ト層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a magnetic recording medium (for example, a magnetic tape, a magnetic disk, etc.) and a manufacturing apparatus that can be used for the manufacturing.
[0002]
[Prior art]
In recent years, magnetic recording media are used in, for example, audio equipment, video equipment, computer equipment, and the like, and the demand for the recording equipment has been significantly increased.
[0003]
Conventionally, as a magnetic recording medium, a powder magnetic material such as an oxide magnetic powder or an alloy magnetic powder on a nonmagnetic support, such as a vinyl chloride-vinyl acetate copolymer, a polyester resin, a urethane resin, a polyurethane resin, etc. A so-called coating-type magnetic recording medium prepared by applying and drying a magnetic paint dispersed in an organic binder is widely used.
[0004]
On the other hand, with increasing demand for high-density magnetic recording, metallic magnetic materials such as Co—Ni alloy, Co—Cr alloy, and Co—O are plated or vacuum thin film forming means (vacuum deposition method or sputtering method, A so-called metal magnetic thin film type magnetic recording medium directly deposited on a nonmagnetic support such as a polyester film, polyamide, or polyimide film by a so-called PVD technique such as an ion plating method has been proposed and attracting attention.
[0005]
This metal magnetic thin film type magnetic recording medium has excellent coercive force and squareness ratio, and the thickness of the magnetic layer can be made extremely thin. Therefore, the thickness loss during recording demagnetization and reproduction is extremely small, and the electromagnetic conversion characteristics at short wavelengths. In addition, the magnetic layer does not need to be mixed with a binder which is a non-magnetic material, and thus has a number of advantages such as an increased packing density of the magnetic material.
[0006]
That is, the metal magnetic thin film type magnetic recording medium is considered to become the mainstream of high-density magnetic recording because of its superior magnetic properties.
[0007]
Further, in order to improve the electromagnetic conversion characteristics of this type of magnetic recording medium and obtain a larger output, when forming the magnetic layer of the magnetic recording medium, the magnetic layer is deposited obliquely, so-called Oblique vapor deposition has been proposed and put into practical use.
[0008]
By the way, especially in the metal magnetic thin film type magnetic recording medium, since the density is further increased, the medium tends to be smoothed in order to reduce the spacing loss. However, if the smoothness of the surface of the magnetic layer is good, the substantial contact area with respect to the sliding member such as the magnetic head or the guide roller becomes large, and therefore the friction coefficient becomes large, and the adhesion phenomenon (so-called sticking) The shear stress generated in the medium is large, such as lack of running performance and durability, and there are many problems.
[0009]
For example, a tape inserted into an 8 mm video deck is wound around a drum through 10 or more guide pins. At that time, the tape tension and the tape running speed are kept constant by the pinch roller and the capstan, the tension is about 20 g, and the running speed is 0.5 cm / s.
[0010]
In this traveling system, the magnetic layer of the tape is in contact with a fixed guide pin made of stainless steel. For this reason, when the friction on the tape surface increases, the tape causes stick-slip, and a so-called tape squealing phenomenon occurs, which causes the playback screen to be dragged.
[0011]
In addition, the relative speed between the tape and the head is very high, and particularly in the paused state, high-speed contact is made at the same place. This causes a problem of wear of the magnetic layer, leading to a decrease in reproduction output. In the case of a vapor deposition tape in which the magnetic layer is formed by vapor deposition, this problem is further promoted because the magnetic layer is very thin.
[0012]
In the hard disk device, CSS (contact start / stop) is a type in which the magnetic head is in contact with the disk before rotation and floats by the generated air flow when rotation starts at high speed. Therefore, since the vehicle runs while rubbing the medium at the time of start / stop or start-up, the increase in friction at that time is a big problem.
[0013]
In order to maintain the product level reliability, it is desirable that the coefficient of friction after 20,000 CSS operations is 0.5 or less. In addition, since it rotates at a high speed, the problem of head crash due to the head and the medium is one of the problems in the thin film medium.
[0014]
In such a situation where sliding durability becomes severe, a technique for forming a protective film on the surface of the magnetic layer has been studied for the purpose of improving durability and corrosion resistance.
[0015]
Such protective films include carbon films, quartz (SiO₂) Film, zirconia (ZrO₂) Films etc. have been studied, and some hard disks have been put into practical use and produced.
[0016]
In particular, the formation of diamond-like carbon (DLC: carbon having a diamond structure) film as a hard carbon film having a hardness higher than that of the carbon film has recently been studied, and it will be mainstream in the future. It is a protective film.
[0017]
As a method for forming this DLC film, a sputtering method or a CVD method (Chemical Vapor Deposition) is used.
[0018]
Sputtering is an ionization (plasmaization) of an inert gas such as argon gas using an electric field or magnetic field, and the target atoms are knocked out by kinetic energy obtained by accelerating the ionized ions. . Then, the knocked-out atoms are deposited on the opposing substrate to form a target film.
[0019]
In contrast, the CVD method (particularly the plasma CVD method) uses plasma energy generated using an electric field or magnetic field to cause a chemical reaction such as decomposition or synthesis of the gas used as a raw material to form a film. Is a chemical process.
[0020]
In general, the formation of a DLC film by a sputtering method is slower than the CVD method and the film quality is inferior, so that the formation by the CVD method (particularly, the plasma CVD method) is the mainstream.
[0021]
Further, in order to pursue further durability and corrosion resistance, it has been proposed to subject the surface of a hard carbon film (hard carbon protective film) to fluorination treatment (see JP-A-63-78328).
[0022]
In a magnetic recording medium in which a metal magnetic thin film is provided on a nonmagnetic support, a diamond-like hard carbon film is disposed on the surface, and the surface of the diamond-like hard carbon film is fluorinated, A fluorine-containing lubricant layer is provided thereon.
[0023]
Thus, by fluorinating the surface of the hard carbon film, a fluororesin film such as polytetrafluoroethylene [PTFE :-( CF₂CF₂)_n-] Is obtained, and this polytetrafluoroethylene film is a film excellent in environmental resistance such as heat resistance and corrosion resistance. This is a fluorine resin that has a small fluorine atom size, the largest electronegativity among all atoms, a strong bond between carbon atoms and fluorine atoms in the molecule, and a small surface free energy. It is thought that it originates in the property peculiar to a film (especially polytetrafluoroethylene film).
[0024]
However, by subjecting the outermost surface of the hard carbon film, that is, the hard carbon protective film, to fluorination (formation of a fluororesin film), the corrosion resistance is improved and the friction is reduced. Since the surface free energy of the surface is relatively small, it is difficult to have a sufficient amount of fluorine-based lubricant such as perfluoropolyether on the surface for a long time in a situation where sliding durability is severe. It becomes. As a result, a still serious problem remains in the formation of the lubricant layer, such as deterioration of still durability and shuttle durability over time.
[0025]
[Problems to be solved by the invention]
The present invention has been made in view of such conventional circumstances, and its purpose is to provide a fluoridation excellent in corrosion resistance and the like on a hard carbon film which is a surface protective film of a magnetic layer made of a metal magnetic thin film. A method of manufacturing a magnetic recording medium, in which a treatment film is provided, and a lubricant layer that can exist for a long period of time in a severe condition such as sliding durability is provided on this surface, and in the implementation thereof An object of the present invention is to provide an apparatus for manufacturing a magnetic recording medium that can be suitably used.
[0026]
[Means for Solving the Problems]
That is, the present invention includes a step of forming a hard carbon film on a magnetic layer made of a metal magnetic thin film, a step of forming a fluorinated film on the hard carbon film, and treating the fluorinated film in plasma. And a step of providing a fluorine atom-containing lubricant layer on the treated surface.And
When the surface of the fluorinated film is cleaned by bombardment in the plasma  The surface free energy of the fluorinated film is 30 mJ / m by expressing both functional groups. ² Less than  Above, 45mJ / m ² And
After the bombardment treatment, the treated surface of the fluorinated membrane is in an activated state while the fluorinated membrane is in the activated state.  Provide a fluorine atom-containing lubricant layer,
The present invention relates to a method for manufacturing a magnetic recording medium (hereinafter referred to as a manufacturing method of the present invention).
[0027]
According to the manufacturing method of the present invention, a step of forming a hard carbon film (particularly DLC: diamond-like carbon film) on a magnetic layer made of a metal magnetic thin film (for example, a continuous magnetic thin film of cobalt), A step of forming a fluorinated film (for example, a polytetrafluoroethylene film), a step of processing the fluorinated film in a plasma (for example, plasma of nitrogen molecules, oxygen molecules, argon atoms, etc.), And a step of providing a fluorine atom-containing lubricant layer (for example, a perfluoropolyether lubricant layer) on the hard carbon film which is a surface protective film. The fluorine atom-containing lubricant layer that can exist for a long time in a sufficient amount even under severe conditions such as sliding durability can be provided on the surface.
[0028]
In particular, in the production method of the present invention, the fluorinated film is used in plasma.BombardHas a process to process,in this wayFluorinated film in plasmaBombardBy performing the treatment (hereinafter sometimes referred to as plasma treatment), the surface of the fluorinated film (for example, polytetrafluoroethylene film) is bombarded by plasma of, for example, oxygen molecules, argon atoms, nitrogen molecules, etc. The surface becomes clean and moderate roughness occurs, and functional groups such as> C═O,> C—O—, —OH, and —COOH appear on the surface. In the production method of the present invention, the fluorine atom-containing lubricant is adsorbed to the fluorinated film through these functional groups, and the fluorinated film exhibits an appropriate roughness. It is considered that the agent layer firmly adheres (adsorbs) to the surface of the fluorinated film.
[0029]
That is, the manufacturing method of the present invention further comprises a plasma treatment on the surface of the fluorinated hard carbon film.(Bombard)To activate the surface of the hard carbon film,In this activated stateIt promotes the adsorption of lubricant.
However, the above functional groups tend to lose their activity over time. Therefore, it is important to provide a fluorine atom-containing lubricant layer after the treatment in the plasma while the treated surface is in an activated state.
In this case, the surface free energy of the fluorinated film (for example, polytetrafluoroethylene film) is set to 30 mJ / m by treatment in plasma. ² 45 mJ / m ² It is important to set a specific range as follows. However, the above surface free energy is the surface energy immediately after the plasma treatment, and was obtained from the contact angle of water and methylene iodide using the contact angle CA-DT manufactured by Kyowa Interface Science Co., Ltd. (hereinafter the same). In order to remove the adsorbed water as much as possible and measure the surface energy of the film itself, the measurement was performed while performing a nitrogen purge. The temperature at the time of measurement is room temperature.
Generally, the surface free energy of a fluorinated film (for example, polytetrafluoroethylene film) is small, excellent in water resistance and oil resistance, and effective as a corrosion resistant film, but the surface free energy is 20 mJ / m. ² If it is too small and less, for example, a fluorine atom-containing lubricant layer such as perfluoropolyether becomes difficult to adhere, and it becomes difficult to allow the lubricant layer to act sufficiently for a long time in an environment with severe sliding durability. Tend. This surface free energy is 30 mJ / m. ² 45 mJ / m ² Should be:
[0030]
The present invention also provides a first reaction chamber for forming the hard carbon film on the magnetic layer made of the metal magnetic thin film, a second reaction chamber for forming the fluorinated film on the hard carbon film, A plasma processing chamber for processing fluorinated films in plasmaAnd
The surface of the fluorinated film is cleaned by bombardment in the plasma processing chamber.  And the surface free energy of the fluorinated film is 30 m.  J / m ² 45 mJ / m ² And
After the bombardment treatment, the treated surface of the fluorinated membrane is in an activated state while the fluorinated membrane is in the activated state.  Constructed to be provided with a fluorine atom-containing lubricant layer,
The present invention relates to a magnetic recording medium manufacturing apparatus (hereinafter referred to as a manufacturing apparatus of the present invention).
[0031]
According to the manufacturing apparatus of the present invention, the first reaction chamber for forming a hard carbon film on a magnetic layer made of a metal magnetic thin film, the second reaction chamber for forming a fluorinated film on the hard carbon film, And a plasma treatment chamber for treating the fluorination treatment film in plasma, so that the fluorination treatment film (for example, polytetrafluoroethylene) having excellent corrosion resistance in the second reaction chamber is formed on the hard carbon film. In addition, since the plasma treatment is performed on the fluorinated film in the plasma treatment chamber, the treated surface has a sufficient amount even under severe conditions such as sliding durability. A fluorine atom-containing lubricant layer (for example, a perfluoropolyether lubricant layer) that can exist for a long time can be formed.
[0032]
The manufacturing apparatus of the present invention has a plasma processing chamber for processing a fluorinated film in plasma. In this plasma processing chamber, plasma of oxygen molecules, nitrogen molecules, argon atoms, etc. is generated, and by the bombardment by this plasma, the surface of the fluorinated film can be cleaned and moderate roughness can be generated. Further, a functional group such as> C═O,> C—O—, —OH, —COOH or the like can also appear on this surface. These functional groups and appropriate roughness have an effect of firmly adhering (chemical adsorption) the lubricant layer to the fluorinated film.
[0033]
That is, according to the manufacturing apparatus of the present invention, the plasma treatment is further performed on the surface of the fluorinated hard carbon film.(Bombard)To activate the surface of the hard carbon film and promote the adsorption of the lubricant.Therefore, as in the manufacturing method of the present invention, the surface of the fluorinated film is made clean and moderately rough by bombardment with plasma, and the surface free energy is 30 mJ / m. ² 45 mJ / m ² The specific range is set as follows, and further, functional groups such as>C═O,> C—O—, —OH, and —COOH can be expressed on the surface. These functional groups, appropriate roughness, and surface free energy have an effect of firmly attaching (chemical adsorption) the lubricant layer to the fluorinated film.
However, the above functional group tends to lose its activity over time. Therefore, it is important to provide a fluorine atom-containing lubricant layer after the treatment in the plasma while the treated surface is in an activated state.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
In the production method of the present invention and the production apparatus of the present invention, in a plasma of at least one gas selected from the group consisting of a nitrogen atom-containing gas, an oxygen atom-containing gas, and an inert gas.BombardTreatment (plasma treatment) can be performed.
[0035]
Examples of these gases include nitrogen gas and ammonia gas as nitrogen atom-containing gas, oxygen gas and carbon dioxide gas as oxygen atom-containing gas, and argon gas as inert gas. Of course, these gases may be used alone or in combination.
[0036]
By performing plasma treatment on the surface of the fluorinated film using such a gas, it is possible to expect further improvement in adsorptivity, thereby sufficiently adsorbing the lubricant and fully extracting the characteristics of the lubricant. .
[0037]
Moreover, in the manufacturing method of the present invention and the manufacturing apparatus of the present invention, in the plasma, one kind of processing method selected from the group consisting of DC discharge processing, AC discharge processing and high frequency discharge processing is used.BombardTreatment (plasma treatment) can be performed.
[0038]
That is, the plasma processing chamber may be any of a direct current (DC) discharge unit, an alternating current (AC) discharge unit, and a high frequency (RF) discharge unit, and the plasma processing chamber is configured to be suitable for each processing method. it can.
[0042]
In the production method and production apparatus of the present invention, the hard carbon film can be diamond-like carbon, the fluorinated film can be a fluororesin film, and the lubricant layer can be perfluoropolyether.
[0043]
The hard carbon film is called diamond-like carbon, i-carbon (where i is i of ion), etc., and sp between carbon atoms.³It is an amorphous carbon film mainly composed of bonds and mixed with a diamond structure or a graphite structure.
[0044]
In general, a hard carbon film is a very hard film having an insulating property, a high refractive index, and a very smooth form (morphology). Depending on the preparation conditions, diamond microcrystals may be included. In general, a hydrogen atom is softened, and a relatively soft film containing hydrogen is called “aC: H”. In the present invention, the thickness is preferably about 5 to 30 nm.
[0045]
Moreover, the said fluororesin film | membrane is a resin film obtained by superposition | polymerization of the olefin containing a fluorine, Polytetrafluoroethylene (PTFE) is mentioned as a typical thing. In the present invention, a very thin film (about 3 to 4 nm thick) obtained by fluorination treatment (for example, plasma CVD method) using ethylene as a source gas is preferable.
[0046]
Furthermore, the lubricant layer is preferably a fluorine-containing lubricant layer, and the perfluoropolyether is particularly preferable. Perfluoropolyether (PFPE) has the general formula:

(However, n represents the degree of polymerization and is an arbitrary natural number.)
Examples thereof include Teflon PFA (manufactured by DuPont), Teflon PFA-J (manufactured by Mitsui DuPont), and the like. In the present invention, the lubricant layer (perfluoropolyether layer) preferably has a thickness of 1 to 5 nm.
[0047]
In the production method and the production apparatus of the present invention, it is preferable that the hard carbon film is formed by a plasma CVD method.
[0048]
Generally, as a method of forming a hard carbon film (DLC film), a sputtering method or a CVD method (Chemical Vapor Deposition) is used.
[0049]
In particular, the CVD method has a relatively high film formation rate and can sufficiently form an excellent quality film.
[0050]
In the manufacturing method of the present invention, while transporting a non-magnetic support provided with a magnetic layer made of a metal magnetic thin film, the formation of a hard carbon film, the formation of a fluorinated film, and the treatment in plasma are sequentially performed. It can be carried out.
[0051]
Thus, in a series of steps, formation of a hard carbon film, formation of a fluorination treatment film, and treatment in plasma can be performed, which is a method excellent in productivity, economy, and the like.
[0052]
Moreover, in the manufacturing apparatus of this invention, it is preferable that the 1st reaction chamber, the 2nd reaction chamber, and the plasma processing chamber are arrange | positioned in the common vacuum chamber. However, each chamber is not limited to being disposed in the same vacuum chamber.
[0053]
Furthermore, in the manufacturing apparatus of the present invention, the formation of the hard carbon film in the first reaction chamber, the formation of the fluorination treatment film in the second reaction chamber, and the treatment in the plasma processing chamber are sequentially performed. can do.
[0054]
With the manufacturing apparatus having such a configuration, the space in the manufacturing apparatus can be effectively used, and the manufacturing apparatus is excellent in productivity and economy.
[0055]
Next, the configuration of an example of the manufacturing apparatus of the present invention will be described with reference to FIG.
[0056]
The manufacturing apparatus shown in FIG. 1 sequentially provides a hard carbon film and a fluorinated film on a magnetic recording medium provided with a metal magnetic thin film on a nonmagnetic support, and further plasma-treats the fluorinated surface. This is an apparatus for manufacturing a magnetic recording medium.
[0057]
In this manufacturing apparatus, a raw film 21 provided with a metal magnetic thin film is processed for a magnetic recording medium. This film is introduced while introducing oxygen gas onto a nonmagnetic support film made of polyethylene terephthalate (PET). Cobalt (Co) is deposited to form a partially oxidized ferromagnetic metal thin film. The film 21 is supported by a rotating support (guide roller) 20 and is applied with a predetermined tension, while the unwinding roll 18, the counter electrode 5, the first reaction chamber 2, the second reaction chamber 3, the plasma processing chamber 4, It is conveyed in the order of the winding roll 19.
[0058]
The first reaction chamber 2 is for forming a hard carbon film, the fluorination treatment chamber (second reaction chamber) 3 is for fluorination treatment of a hard carbon film, and the plasma treatment chamber 4 is for plasma treatment of a fluorination treatment film. Each chamber is provided in a common vacuum chamber 1, and the vacuum chamber 1 is evacuated by a vacuum exhaust device (not shown).
[0059]
An electrode 7 is incorporated inside the first reaction chamber 2, and a potential of +500 to 2000 V is applied to the electrode 7 by a DC power supply 8. The electrode 7 is a metal mesh electrode, such as a wire mesh, which is easy to pass gas (plasma source gas) and can generate an electric field uniformly in the reaction chamber and has high flexibility. preferable. The material of the electrode 7 is typically copper, but gold and the like are also mentioned from the viewpoint of conductivity. Further, like the second reaction chamber, it is desirable that the walls of the reaction chamber be made of an insulator having a small linear expansion coefficient, such as glass, resin, and ceramics. Reference numeral 6 denotes a raw material gas inlet, from which a raw material gas 15 mainly composed of a hydrocarbon such as toluene is introduced.
[0060]
Similarly to the first reaction chamber, an electrode 9 is incorporated in the second reaction chamber (fluorination treatment chamber) 3, and an appropriate potential is applied to the electrode 9 by a DC power source 11. The shape, material, etc. of the electrode 9 are the same as those of the electrode 7 described above. Reference numeral 10 denotes a raw material gas inlet, from which a raw material gas 16 such as ethylene is introduced.
[0061]
Further, the plasma processing chamber 4 is provided with an electrode 14 and a counter electrode 13 so that a predetermined voltage is applied from the AC power source 22 to the electrode 14. However, as described above, a DC voltage can be applied to the electrode 14 and the counter electrode 13, or a high frequency power can be supplied by winding an excitation coil around the outer periphery of the processing chamber. Reference numeral 22 denotes an inlet for the plasma processing gas 17, from which a gas such as nitrogen, oxygen, or argon is introduced. However, these plasma processing gases 17 may be subjected to plasma processing while being confined after introduction.
[0062]
In addition, a large pressure difference is provided between the first reaction chamber 2, the second reaction chamber 3, the plasma processing chamber 4, and the outer periphery by a vacuum exhaust device (not shown) provided in the vacuum chamber 1, Gases not subjected to the reaction (for example, raw material gas itself, decomposition gas, carrier gas, etc.) are the first reaction chamber 2, the gaps 24 and 25 between the second reaction chamber 3 and the counter electrode 5, and further the plasma. The medium is exhausted from the medium transport port 26 of the processing chamber 4 without backflow.
[0063]
The film that has been plasma-treated in this manner is drawn out again after winding, and a fluorine-containing lubricant is attached to the plasma-treated surface by roll coating or the like (not shown) while maintaining the activated state by the plasma treatment.
[0064]
The production method of the present invention and the production apparatus of the present invention provide a magnetic recording medium (tape, disk, etc.) in which a magnetic recording layer (magnetic layer) is provided on a nonmagnetic support and a hard carbon protective film is further provided thereon. Although all of them are targeted, the effect is particularly great for a tape medium that requires severe environmental resistance.
[0065]
Next, FIG. 2 shows a structural example of a magnetic recording medium manufactured by the manufacturing method of the present invention and the manufacturing apparatus of the present invention.
[0066]
In the magnetic recording medium 31 in which the metal magnetic thin film 33 is provided on the nonmagnetic support 32, a hard carbon film 34 is disposed on the surface, and a fluorination treatment film 35 is provided on the surface of the hard carbon film 34. A surface 39 on the fluorinated film 35 is subjected to plasma treatment, and a fluorine-containing lubricant layer 36 is provided thereon. However, the magnetic recording medium manufactured by the manufacturing method of the present invention and the manufacturing apparatus of the present invention is not limited to the magnetic recording medium having this structure.
[0067]
A metallic magnetic thin film is formed as a magnetic layer by directly depositing a ferromagnetic metal material on the nonmagnetic support, and this metal magnetic material is used for ordinary vapor deposition tapes and the like. Any material can be used.
[0068]
For example, ferromagnetic metals such as Fe, Co, Ni, Fe—Co, Co—Ni, Fe—Co—Ni, Fe—Cu, Co—Cu, Co—Au, Co—Pt, Mn—Bi, Mn Examples include ferromagnetic alloys such as -Al, Fe-Cr, Co-Cr, Ni-Cr, Fe-Co-Cr, Co-Ni-Cr, and Fe-Co-Ni-Cr. These may be a single layer film or a multilayer film. The thickness of the metal magnetic thin film is usually 0.02 to 1 μm.
[0069]
Furthermore, in the case of a non-magnetic support and a metal magnetic thin film, or in the case of a multilayer film, an underlayer or an intermediate layer may be provided in order to improve the adhesion between each layer and control the coercive force.
[0070]
As a means for forming a metal magnetic thin film, a vacuum deposition method in which a ferromagnetic material is heated and evaporated under vacuum and deposited on a nonmagnetic support, an ion plating method in which the ferromagnetic material is evaporated in a discharge, argon is used. You may use what is called PVD techniques, such as the sputtering method which raise | generates glow discharge in the atmosphere which has a main component, and knocks out the atom of a target surface with the produced | generated argon ion.
[0071]
Of course, the configuration of the magnetic recording medium (especially the magnetic tape) of the present invention is not limited to this, and modifications within the range not departing from the gist of the present invention, for example, a back coat as shown by a one-dot chain line in FIG. The layer 37 may be formed, an undercoat layer may be formed on the nonmagnetic support, or a layer such as a lubricant (but different from the lubricant layer 36 in FIG. 2) may be formed. As the nonmagnetic support, the nonmagnetic pigment contained in the backcoat layer, the resin binder, or the material contained in the lubricant, any conventionally known materials can be used.
[0072]
【Example】
Hereinafter, the present invention will be described in detail with reference to specific examples.
[0073]
This example relates to a magnetic recording medium (especially a magnetic tape) having a magnetic layer made of a metal magnetic thin film on a nonmagnetic support, and the production conditions are shown below.
[0074]
Preparation conditions of vapor deposition tape (raw fabric);
Non-magnetic support: polyethylene terephthalate (PET) with a thickness of 10 μm
Magnetic layer: thickness 200 nm, composition: single layer film of Co80% -Ni20% alloy
Incident angle: 45 ° to 90 °
Introduction gas: Oxygen gas
Degree of vacuum during deposition: 2 × 10^-2Pa
[0075]
Next, using the manufacturing apparatus shown in FIG. 1, a hard carbon film (DLC film) was formed, a fluorinated film (polytetrafluoroethylene (PTFE) film) was formed, and a plasma treatment was performed. Each film forming condition is as follows.
[0076]
DLC film formation conditions;
Source gas: Toluene
Reaction pressure: 10 Pa
Installed power: DC2.0kV
Film thickness: 8nm
[0077]
Film formation conditions for PTFE film
Source gas: Tetrafluoroethylene (C₂F₄)
Reaction pressure: 20 Pa
Installed power: DC 1.0 kV
Film thickness: 3-4nm
[0078]
However,Example 9 (Comparative example3)Is a sample tape in which a lubricant is directly applied after forming a DLC film without forming a PTFE film. Also,Example 10 (Comparative example4)Is a sample tape in which a lubricant is directly applied without plasma treatment after the formation of the PTFE film on the DLC film.
[0079]
Next, Examples 1-8(However, Example 5 is Comparative Example 1 and Example 8 is Comparative Example 2)The plasma treatment of the PTFE film on the DLC film was performed under the conditions shown in Table 1 below. Also,underIn Table 1, the surface free energy is a value before forming the lubricant layer, and the measurement method has been described above.
[0080]
Next, a back coat layer made of carbon and urethane resin is applied to the surface of the nonmagnetic support opposite to the surface on which the magnetic layer is formed to a thickness of 0.6 μm, and the plasma treatment surface is activated. While maintaining the state, a lubricant composed of perfluoropolyether (PFPE) was applied to a thickness of 2 μm, and then the raw fabric was cut into a width of 8 mm to produce a magnetic tape.
[0081]
Next, Examples 1 to10The sample tape was evaluated for dynamic friction coefficient, still durability, shuttle durability, and saturation magnetization change.
[0082]
Coefficient of dynamic friction: The coefficient of dynamic friction after 100 passes in an environment of a temperature of 40 ° C. and a humidity of 80% was measured.
[0083]
Still durability: The time (minutes) required for the reproduction output value to drop 3 dB from the initial value at a temperature of -5 ° C. An 8 mm video deck “EVO9500” manufactured by Sony was used for this measurement.
[0084]
Shuttle durability: Under an environment of a temperature of 40 ° C. and a humidity of 20%, the deterioration amount (dB) with respect to the initial value of the reproduction output value after 100 passes was measured. An 8 mm video deck “EVO9500” manufactured by Sony was used for this measurement.
[0085]
Corrosion resistance test: In a thermostat maintained at a temperature of 30 ° C. and a relative humidity of 70%, an SO concentration of 0.5 ppm is further added.₂Introducing gas to make it easy to generate rust, etc.10An environmental resistance test (corrosion resistance test) was performed in which the sample tape was stored for 3 days. Here, the amount of change in saturation magnetization before and after storage was measured, and evaluation was performed according to the following equation (1).
[0086]
ΔMs = [Ms ′ (after storage) −Ms (before storage)] / Ms (before storage) (1)
(However, ΔMs indicates the amount of change (%) in saturation magnetization.)
[0087]
Example 110Table 1 below shows the measurement results for each plasma treatment condition, surface free energy, and evaluation items for the sample tape.
[0088]

[0089]

[0090]
<Result>
Based on the present inventionExample 14, 6 and 7As described above, before forming the lubricant layer made of perfluoropolyether, the surface of the fluorinated film made of polytetrafluoroethylene is plasmad using a gas such as nitrogen, ammonia, oxygen, or argon.(Bombard)processingThe surface free energy is 30 to 45 mJ / m ² WhenThe obtained sample tape has improved still durability and shuttle durability. This is because the plasma treatment makes it easy for the lubricant to be adsorbed (adhered) to the surface, so that it seems that the characteristics of the lubricant are sufficiently drawn out for a long time. In addition, the storage characteristics are greatly improved, and the corrosion resistance as well as the durability can be improved at the same time.
[0091]
Also an example9Is a sample tape in which a lubricant is applied directly to the surface of the DLC film without providing a fluorinated film, and the amount of change in saturation magnetization is very large, that is, the deterioration with time is severe. It can be said that the sample tape is inferior in property.
[0092]
Also an example10Is a sample tape in which a plasma treatment is not performed and a fluorination treatment film and a lubricant are sequentially provided on the DLC film. Although it is excellent in corrosion resistance because it is provided with a fluorinated film, it can be said that it is a sample tape that is inferior in durability because its surface free energy is too small and the lubricant is easily detached because it is not subjected to plasma treatment. .
[0093]
Moreover, it turns out that gas, such as the above-mentioned nitrogen atom containing gas, oxygen atom containing gas, and inert gas, can be used for the gas used for a plasma processing like the sample tape of Examples 1-4.
[0094]
In addition, Examples 1 to4, 6 and 7;ExampleComparison with 5, 8 and 9-10Therefore, the surface free energy of the fluorinated film surface is30mJ / m²If it is above, the lubricant is easily adsorbed (adhered), and the characteristics of the lubricant are sufficiently extracted.45mJ / m² If it is below, the change in saturation magnetization or deterioration over time will be considerably reduced.I understand that.
[0095]
in this way,Based on the present inventionBy further plasma-treating the hard carbon film surface that has been subjected to the fluorination treatment, the hard carbon film surface is activated and the adsorption of the lubricant is promoted. The characteristics of the agent can be fully exploited, and the corrosion resistance and durability can be improved at the same time. Therefore, the reliability of the magnetic recording medium itself is improved, and it is possible to provide a magnetic recording medium that can withstand special applications such as a data streamer and a video library that need to be stored for a long time.
[0096]
While the present invention has been described with reference to the embodiments, the present embodiments can be further modified based on the technical idea of the present invention.
[0097]
For example, a polytetrafluoroethylene film formed by CVD using ethylene as a source gas is shown as the fluorination treatment film. However, for example, polytetrafluoroethylene (PTFE) may be formed by a coating method. The material of the fluorinated film may be other fluororesin.
[0098]
The plasma processing chamber may be any discharge method using a DC power supply, an AC power supply, or a high-frequency power supply. As a plasma excitation method, a thermionic discharge type, a bipolar discharge type, a magnetic field convergence type (magnetron) Various methods such as a discharge type), an electrodeless discharge type, and an ECR discharge type can be used.
[0099]
Further, as the fluorine-containing lubricant, other fluorine-containing lubricants other than perfluoropolyether may be used.
[0100]
The plasma processing chamber may be provided outside the vacuum chamber. Furthermore, in the above-described example, the film was wound around a winding roll after the plasma treatment, and the fluorine-containing lubricant was applied while being unwound from the roll. A contained lubricant may be applied. This can be performed by a coating unit separately provided in the above-described vacuum chamber.
[0101]
Furthermore, the magnetic recording medium according to this embodiment shown in FIG. 2 may be a magnetic recording medium having a structure in which a fluorination treatment film is provided between the magnetic layer 33 and the hard carbon film 34. That is, a first fluorinated film, a hard carbon film, and a second fluorinated film are sequentially provided on a magnetic layer made of a metal magnetic thin film, and plasma treatment is further performed on the surface of the second fluorinated film. And a lubricant layer may be provided on the outermost surface. In producing the magnetic recording medium having such a configuration, in the manufacturing apparatus shown in FIG. 1, a reaction chamber having the same configuration as the second reaction chamber 3 is provided in front of the first reaction chamber 2. The first fluorinated film can also be formed.
[0102]
[Effects of the invention]
According to the manufacturing method and apparatus of the present invention, a hard carbon film is formed on a magnetic layer made of a metal magnetic thin film.Shi, Forming a fluorinated film on the hard carbon filmShiThe fluorinated film is treated in plasma (for example, plasma of nitrogen molecules, oxygen molecules, argon atoms, etc.)ShiA fluorine atom-containing lubricant layer (for example, a perfluoropolyether lubricant layer) is provided on the treated surface.,
When the surface of the fluorinated film is cleaned by bombardment in the plasma  The surface free energy of the fluorinated film is 30 mJ / m by expressing both functional groups. ² Less than  Above, 45mJ / m ² And
After the bombardment treatment, the treated surface of the fluorinated membrane is in an activated state while the fluorinated membrane is in the activated state.  Provide a lubricant layer containing nitrogen atoms
Therefore, the fluorinated film (for example, polytetrafluoroethylene film) excellent in corrosion resistance and the like is provided on the hard carbon film that is the surface protective film of the magnetic layer made of a metal magnetic thin film, and further, on this surface, The fluorine atom-containing lubricant layer that can exist for a long time in a sufficient amount even under severe conditions such as sliding durabilityWith strong adhesionCan be provided.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a main part configuration diagram of an example of a magnetic recording medium manufacturing apparatus of the present invention.
FIG. 2 is a schematic sectional view of a magnetic recording medium manufactured using the manufacturing apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Vacuum chamber, 2 ... 1st reaction chamber, 3 ... 2nd reaction chamber, 4 ... Plasma processing chamber,
5 ... Counter electrode, 6, 10, 23 ... Gas inlet,
7, 9, 13, 14 ... electrodes, 8, 11 ... DC power supply,
15, 16, 17 ... raw material gas, 18 ... unwinding roll,
19 ... take-up roll, 20 ... rotating support (guide roller),
21, 31 ... Raw film or magnetic recording medium for magnetic recording medium,
22 ... AC power source, 26 ... transport port, 32 ... non-magnetic support, 33 ... magnetic layer,
34 ... Hard carbon film, 35 fluorinated film, 36 ... Lubricant layer,
37 ... Backcoat layer

Claims (13)

A step of forming a hard carbon film on a magnetic layer made of a metal magnetic thin film, a step of forming a fluorination treatment film on the hard carbon film, a step of treating the fluorination treatment film in plasma, and this treatment possess a step of providing a fluorine-containing lubricant layer on the surface,
The bombardment treatment in the plasma, the fluorine process film surface cleaning to the both the fluoride allowed expressing functional groups treated film surface free energy 30 mJ / m ² or more on, and 45 mJ / m ² or less ,
Wherein after bombardment treatment, the treated surface of the fluoride treatment film is provided the full Tsu atom-containing lubricant layer of the active state,
A method of manufacturing a magnetic recording medium. The manufacturing method according to claim 1, wherein the bombardment treatment is performed in a plasma of at least one gas selected from the group consisting of a nitrogen atom-containing gas, an oxygen atom-containing gas, and an inert gas. The manufacturing method according to claim 1, wherein the bombardment treatment in the plasma is performed by one kind of treatment method selected from the group consisting of a direct current discharge treatment, an alternating current discharge treatment, and a high frequency discharge treatment. The manufacturing method according to claim 1, wherein the hard carbon film is diamond-like carbon, the fluorinated film is a fluororesin film, and the lubricant layer is perfluoropolyether. The manufacturing method according to claim 1, wherein the hard carbon film is formed by a plasma CVD method. While carrying the nonmagnetic support provided with the magnetic layer made of the metal magnetic thin film, the hard carbon film is formed, the fluorinated film is formed, and the bombardment process in the plasma is sequentially performed. The manufacturing method according to claim 1. A first reaction chamber for forming a hard carbon film on a magnetic layer made of a metal magnetic thin film, a second reaction chamber for forming a fluorinated film on the hard carbon film, and processing the fluorinated film in plasma have a plasma processing chamber in which,
By the bombardment treatment in the plasma treatment chamber, the surface of the fluorination treatment film is cleaned and the functional group is expressed, and the surface free energy of the fluorination treatment film is 30 m J / m ² or more, 45 mJ / m. ² or less,
After the bombardment treatment, the treated surface of the fluoride treatment film is configured such that the full Tsu atom-containing lubricant layer of the active state is provided,
Magnetic recording medium manufacturing equipment. The manufacturing apparatus according to claim 7 , wherein an atmosphere containing at least one gas selected from the group consisting of a nitrogen atom-containing gas, an oxygen atom-containing gas, and an inert gas is introduced into the plasma processing chamber. The manufacturing apparatus according to claim 7 , wherein the first reaction chamber, the second reaction chamber, and the plasma processing chamber are arranged in a common vacuum chamber. The manufacturing apparatus according to claim 7 , wherein the plasma processing chamber includes one type of discharge unit selected from the group consisting of a DC discharge unit, an AC discharge unit, and a high-frequency discharge unit. The hard carbon film is a diamond-like carbon, the fluoride treatment film is a fluororesin film, a fluorine atom-containing lubricant layer formed on the fluorine resin film is a perfluoropolyether, according to claim 7 manufacturing device. The manufacturing apparatus according to claim 7 , wherein the first reaction chamber for forming the hard carbon film is provided as a plasma CVD apparatus. The formation of the hard carbon film in the first reaction chamber, the formation of the fluorination treatment film in the second reaction chamber, and the bombardment treatment in the plasma treatment chamber are sequentially performed. Item 8. The manufacturing apparatus according to Item 7 .

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