JPS6093638A - Recording medium consisting of thin metallic magnetic film - Google Patents

Abstract

PURPOSE:To obtain a recording medium provided simultaneously with durability and corrosion resistance by forming a resin layer on a recording layer consisting of a thin magnetic metallic film and depositing perfluoropolyether having a carboxylic group at the terminal of the molecule thereon. CONSTITUTION:A film contg. perfluoropolyether having a carboxylic group at the molecule terminal is deposited as a lubricating agent on a resin layer formed on a thin metallic film layer. A protective film having two-layered structure of the resin layer and the perfluoroether layer is thus formed by which corrosion resistance, lubricity and durability are improved. A vinyl chloride/vinyl acetate resin, cellulosic resin, butyral resin, methyl methacrylate, styrene copolymer alone or a blend of >=2 kinds thereof is used as the resin or these resins subjected to crosslinking reaction by bi- or more functional isocyanate compd. are used. The film thickness of the resin layer is made preferably <=1mu. The perfluoropolyether having a carboxyl group at the molecular terminal expressed representatively by the general formula is used as the perfluoropolyether to be deposited on the resin layer. The amt. of the perfluoropolyether to be used is preferably made in 0.01-100mg/m<2> range with respect to the surface of the resin layer.

Description

【発明の詳細な説明】 本発明は金属薄膜型磁気記録媒体に関し耐久性と耐食性
を同時に備えた金属薄膜型磁気記録媒体を提供すること
を目的とする。DETAILED DESCRIPTION OF THE INVENTION An object of the present invention is to provide a metal thin film magnetic recording medium that has both durability and corrosion resistance.

磁気記録の高密度化の要請に対応して開発された金属薄
膜型磁気記録媒体はＦｅ　、　Ｎｉ　、　Ｃｏなどの強
磁性金属またはその合金、あるいはこれらの金属を含む
化合物を公知の蒸着等の方法によってプラスチックフィ
ルム等の基体上に強磁性金属薄膜層を被着形成して作成
されるが金属薄膜層表面はきわめて平滑で走行系ガイド
部材との密着性が良いため、摩擦係数が高くまた、酸化
物系磁性層に比べやわらかいために耐久性に劣）、さら
に空気中の酸素、水分等によって、経日的に酸化劣化し
て磁気特性が低下してくる、りまシ耐食性に劣るという
問題がある。このため磁性層上に脂肪酸、脂肪酸エステ
ルなどの潤滑剤層、あるいはこれら潤滑剤を含むセルロ
ース系樹脂などの樹脂層を形成して磁性層を保護するこ
とが試みられているが、耐久性、耐食性の両特性を充分
に満足できるものではなかった。Metal thin film magnetic recording media developed in response to demands for higher density magnetic recording are made by depositing ferromagnetic metals such as Fe, Ni, Co, alloys thereof, or compounds containing these metals by known methods such as vapor deposition. The metal thin film layer is made by depositing a ferromagnetic metal thin film layer on a substrate such as a plastic film, but the surface of the metal thin film layer is extremely smooth and has good adhesion to the traveling system guide member, so it has a high coefficient of friction and is resistant to oxidation. It is softer than a physical magnetic layer and therefore has poor durability), and also suffers from oxidative deterioration over time due to oxygen and moisture in the air, resulting in a decline in magnetic properties and poor corrosion resistance. be. For this reason, attempts have been made to protect the magnetic layer by forming a lubricant layer such as fatty acids or fatty acid esters, or a resin layer containing these lubricants such as cellulose resin, on the magnetic layer. It was not possible to fully satisfy both characteristics.

すなわち潤滑剤層を金属薄膜層上に直接設けたものは、
使用の初期においては、摩擦係数が低く、艮好な潤滑性
を示すが、もともと金属薄膜層は塗布型磁性薄膜程には
、多孔質でなく層同部に潤滑剤が浸透し、潤滑剤を保持
しておくという特性を有しないために、潤滑剤と金属薄
膜との付着力が弱く、このため長期間にわたる使用では
、テープ走行系の部材との摺接によシ、潤滑剤がはがれ
てしまい十分に耐久性能を有することができない。In other words, the lubricant layer is provided directly on the metal thin film layer.
In the initial stage of use, the coefficient of friction is low and it exhibits excellent lubricity, but the metal thin film layer is not as porous as the coated magnetic thin film, and the lubricant penetrates into the same part of the layer, making it difficult for the lubricant to penetrate. Since the lubricant does not have the property of retaining its properties, the adhesion between the lubricant and the metal thin film is weak, and as a result, during long-term use, the lubricant may peel off due to sliding contact with tape running system members. Therefore, it cannot have sufficient durability.

一方、金属磁性薄膜上に樹ｊ１層を設けることにょハ金
属磁性薄膜表面を機械的損傷から保睦することは公知で
ある。そこでこのような樹脂層中に脂肪酸、脂肪酸エス
テル等の潤滑剤を混入せしめるか、あるいはこのような
樹脂層上に、この極の潤滑剤の被膜を形成することが考
えられるが％曲者の場合、かかる潤滑剤が樹脂層中に混
入されることによって樹脂層の被膜強度を劣化させ、後
者の場合も潤滑剤が樹脂層中に浸み込んで長期間のあい
だに、前者と同様の理由により＃１ｉ脂層被膜強度が劣
化し、しかも記録ヘッドとのスペーシング損失との関係
で樹脂層の厚みを増して補強することができないという
問題があった。そこで樹脂層上に樹脂と相溶しない換言
すれば樹脂層中に浸みこまないシリコンオイル、フッ素
樹脂等を含む被膜を形成することも考えられるが、この
場合に樹脂層と、これら潤滑剤との付着力が弱く、高温
多湿環境下では前述の金ｈＩ４薄１！Ａ層上に潤滑剤層
を直接設けたものと同様に潤滑剤のはがれを生じ、未だ
十分な耐久性能を付与することができない。本発明者は
、従来のこのような欠点を解消し、金属薄膜を機械的損
傷及び化学的腐蝕から保護したりえで十分な潤滑性能を
有する金ＪＩＩ＆薄膜磁気記録媒体を得ようとしての潤
滑剤は樹脂層との付着力が強いこと及び■その反面樹脂
層中に浸み込んで樹脂Ｊ−の強度を弱めることがないと
と■テープ走行系の各柚部材と十分外潤滑性能を有する
こと、の３点を同時に綿足する潤滑剤が必要であるとの
知見を得、これに基づき種々検討した結果、金属薄膜層
上に形成された樹脂層上に潤滑剤として分子末端にカル
ボキシル基を有するパーフルオロポリエーテルを含む被
膜を被着すると、前記の問題点が全て解決されることが
わかった。On the other hand, it is known that the surface of a metal magnetic thin film can be protected from mechanical damage by providing a tree layer on the metal magnetic thin film. Therefore, it is possible to mix a lubricant such as a fatty acid or a fatty acid ester into such a resin layer, or to form a film of this polar lubricant on such a resin layer. When such a lubricant is mixed into the resin layer, it deteriorates the film strength of the resin layer, and in the latter case, the lubricant permeates into the resin layer and over a long period of time, for the same reason as the former. #1i There was a problem in that the strength of the resin layer coating deteriorated, and furthermore, the thickness of the resin layer could not be increased for reinforcement due to the spacing loss with respect to the recording head. Therefore, it is possible to form a film on the resin layer containing silicone oil, fluororesin, etc. that is not compatible with the resin, in other words, does not penetrate into the resin layer, but in this case, the resin layer and these lubricants The adhesion of gold is weak, and the above-mentioned gold hI4 thin 1! Similar to the case where a lubricant layer is directly provided on layer A, the lubricant peels off, and sufficient durability cannot be imparted yet. The present inventor has devised a lubricant to overcome these conventional drawbacks and obtain a gold JII & thin film magnetic recording medium that protects the metal thin film from mechanical damage and chemical corrosion and has sufficient lubricating performance. It has strong adhesion to the resin layer, and ■ On the other hand, it does not penetrate into the resin layer and weaken the strength of the resin J-. ■ It has sufficient external lubrication performance with each Yuzu member of the tape running system. We found that a lubricant that satisfies these three points at the same time, and after conducting various studies based on this knowledge, we developed a lubricant that has a carboxyl group at the end of the molecule as a lubricant on the resin layer formed on the metal thin film layer. It has been found that the application of coatings containing perfluoropolyethers solves all of the problems mentioned above.

この発明によれば金属薄膜上に形成された樹脂層上にパ
ーフルオロポリエーテルのカルボキシル基が強固に付着
し、樹脂層とパーフルオロエーテル層の二層構造を刊す
る保護膜が形成され、耐食性、潤滑性、耐久性に優れた
金属磁性薄膜型高密度磁気記録媒体が＜＋−られる。According to this invention, the carboxyl group of perfluoropolyether is firmly attached to the resin layer formed on the metal thin film, and a protective film with a two-layer structure of the resin layer and the perfluoroether layer is formed, resulting in corrosion resistance. , a metal magnetic thin film type high-density magnetic recording medium with excellent lubricity and durability.

この発明において樹脂層を形成する樹脂としては塩化ビ
ニル−酢酸ビニル系樹脂、セルロース系樹脂、ブチラー
ル樹脂、メチルメタアクリレート、スチレン共正合体等
の単体あるいは二種以上ブレンドしたもの、またこれら
樹脂を三官能以上のイソシアネート化合物で架橋反応さ
せたものが前記のパーフルオロポリエーテルとの付着が
良好なため好適なものとして使用される。これらの樹脂
は被膜性に優れ、そのため磁性層上に良好に樹脂層を形
成して磁性層表面が酸化等によ１１食されるのを有効に
防止する０樹脂層の膜厚は１μ以上にすると磁気ヘッド
と磁性層間のスペーシングロスが大きくなハ出力が低下
するため１μ以下にするのが好ましい。樹脂層上に被着
する分子末端にカルボキシル基を有するパーフルオロポ
リエーテルは代表的なものとして一般式 ％式％ ） で表わされるものが使用される。In this invention, resins forming the resin layer include vinyl chloride-vinyl acetate resins, cellulose resins, butyral resins, methyl methacrylate, styrene copolymerized resins, etc. alone or a blend of two or more of these resins, or three or more of these resins. Those obtained by crosslinking with isocyanate compounds having higher than functional functions are preferably used because they adhere well to the above-mentioned perfluoropolyether. These resins have excellent film properties, and therefore the thickness of the resin layer should be 1μ or more to form a good resin layer on the magnetic layer and effectively prevent the surface of the magnetic layer from being eaten away by oxidation. In this case, the spacing loss between the magnetic head and the magnetic layer is large and the output is reduced, so it is preferable to set the thickness to 1 μm or less. The perfluoropolyether having a carboxyl group at the end of the molecule to be deposited on the resin layer is typically one represented by the general formula %.

具体例としてはＤｕｐｏｕｔ社製、クライトツクス１５
７Ｆ等が挙げられる。またこのパーフルオロポリエーテ
ルの使用量は樹脂層表面に対し、０．０１〜１００■／
Ｉの範囲とすればよい。A specific example is Krytx 15 manufactured by Dupout.
Examples include 7F. In addition, the amount of perfluoropolyether used is 0.01 to 100 μ/cm based on the surface of the resin layer.
It may be within the range of I.

この発明の磁気記録媒体を製造するには真空蒸着、イオ
ンブレーティング、スパッタリング、メッキ等の手段で
、　Ｆｅ％Ｃｏ、Ｎｉなどの強磁性金属または、その合
金、あるいはこれらの金属を含む化合物からなる磁性層
を基体上に形成したのち、前記のいづれかの樹脂をメチ
ルエチルケトン、トルエン等の適当な溶媒に俗解し、磁
性層上に塗布、乾燥し、この様に形成した樹脂層上にさ
らにパーフルオロポリエーテルをフロリナート（３Ｍ社
製）等適当な溶剤に俗解して袷られた溶液を塗布、ある
いは噴霧するか、あるいは樹脂層を形成した媒体をこの
溶液中に浸種して行なえば良い。次にこの発明の実施例
について説明する。To manufacture the magnetic recording medium of the present invention, a method such as vacuum evaporation, ion blasting, sputtering, plating, etc. is used to prepare a magnetic recording medium made of a ferromagnetic metal such as Fe%Co or Ni, an alloy thereof, or a compound containing these metals. After the magnetic layer is formed on the substrate, one of the resins mentioned above is dissolved in a suitable solvent such as methyl ethyl ketone or toluene, coated on the magnetic layer and dried, and a perfluoropolymer is further applied on the resin layer thus formed. This can be carried out by coating or spraying a solution of ether mixed with a suitable solvent such as Fluorinert (manufactured by 3M), or by soaking a medium on which a resin layer has been formed into the solution. Next, embodiments of this invention will be described.

〈実施例１〉 巻取式連続蒸着装置を用いて、表面処理（プラズマ処理
）され７’ｃ１２μ色厚のポリエステルベースフィルム
の表面にコバルト金属を０．２μｍ厚に真空蒸着して磁
′注層ヶ形成した。次いでこの磁性層上にＶＡｃｎ（米
国ＵＣＣＣＣ社製塩化ビニル−ヒニルービニルアルコー
ル共重合体）２重量ａｔ−９ｓ重量部のメチルイソブチ
ルケトンに溶解して得られた溶液を塗布、乾燥して、Ｖ
ＡＧＨからなる樹脂層を形成し、さらにこの樹脂層上に
ｌｕ記（１）式からなるＤｕｐｏｕｔ社製、ＫＲＹ−Ｔ
ＯＸ１５７Ｆ　０．２重量部を１００重量部のフロリナ
ートＦＣ，７７（３Ｍ社製）に溶解して得られた溶液を
塗布し乾燥した後、８闘幅に裁断して磁気テープをつく
った。<Example 1> Cobalt metal was vacuum-deposited to a thickness of 0.2 μm on the surface of a surface-treated (plasma-treated) polyester base film with a color thickness of 7′ and 12 μm using a winding continuous vapor deposition apparatus to form a magnetic coating layer. Formed. Next, on this magnetic layer, a solution obtained by dissolving VAcn (vinyl chloride-hinyl vinyl alcohol copolymer manufactured by UCCCC, USA) in 2 parts by weight at-9s of methyl isobutyl ketone was coated and dried.
A resin layer made of AGH is formed, and KRY-T made by Dupout and made of the formula (1) is further formed on this resin layer.
A solution obtained by dissolving 0.2 parts by weight of OX157F in 100 parts by weight of Fluorinert FC, 77 (manufactured by 3M) was coated and dried, and then cut into 8 widths to produce magnetic tapes.

〈実施例２〉 実施例１におけるＶＡＧＨにかえて旭化邸）製ニトロセ
ルロースＨ１／２を用いた以外は実施例１と同様にした
。<Example 2> The same procedure as in Example 1 was carried out except that nitrocellulose H1/2 manufactured by Asahika Tei Co., Ltd. was used instead of VAGH in Example 1.

〈実施例３〉 実施例１におけるＶＡＧＨにかえてＶＡＧＨｌ、６重量
部、日本ポリウレタン製ポリイソシアネート０．４重量
部を９８重量部のメチルイソブチルケトンに溶解して得
られた溶液を用いた以外は実施例１と同様にした。<Example 3> Except that VAGH in Example 1 was replaced with a solution obtained by dissolving 6 parts by weight of VAGHl and 0.4 parts by weight of polyisocyanate manufactured by Nippon Polyurethane in 98 parts by weight of methyl isobutyl ketone. The same procedure as in Example 1 was carried out.

〈比較例１〉 実施例１においてＫＲＹＴＯＸ　１５７Ｆ液の塗布、乾
燥工程を省いた以外は、実施例１と同様にした。<Comparative Example 1> The same procedure as in Example 1 was carried out except that the steps of applying the KRYTOX 157F liquid and drying were omitted.

く比較例２〉 実施例１においてＶＡＧＨ樹脂層の形成を省いた以外は
実施例１と同様にした。Comparative Example 2 The same procedure as Example 1 was carried out except that the formation of the VAGH resin layer was omitted.

〈比較例３〉 実施例１においてＫＲＹＴＯＸ　１５７Ｆ　Ｑ液にかえ
てミリスチン酸０．２重量部をＭＩ　ＢＫ　（メチルイ
ソブチルケトン）１００重量部に溶解して得られた溶液
を用いた以外は、実施例１と同様にした。<Comparative Example 3> Example 1 except that a solution obtained by dissolving 0.2 parts by weight of myristic acid in 100 parts by weight of MI BK (methyl isobutyl ketone) was used instead of the KRYTOX 157F Q solution. Same as 1.

く比較例４〉 実施例１においてＫＲＹＴＯＸ１５７Ｆ溶液にかえてシ
リコンオイルＫＦ９６Ｈ（信越化手製）０．１ｆｉ量部
をＭＩＢＫ　１００重量部に溶解して得られた溶液を用
いた以外は実施例１と同様にした。Comparative Example 4> Same as Example 1 except that instead of the KRYTOX157F solution in Example 1, a solution obtained by dissolving 0.1 parts of silicone oil KF96H (manufactured by Shin-Etsu Chemical) in 100 parts by weight of MIBK was used. I made it.

く比較例５〉 実施例１においてＶ　Ａ　Ｇ　Ｈ樹脂層の形成および、
ＫＲＹＴＯＸ１５７Ｆ溶液の塗布、乾燥工程を省いた以
外は実施例１と同様にした０ 各実施例および比較例で得られた磁気テープについて耐
久性、耐食性を試捩した０耐久性試験は２５℃、６０％
ＲＨの条件下に、ヘッド荷重５９走行速度０．０４８ｒ
ｎ／　ａｃｅで得られた磁気テープを走行させて再生し
、出力が初期出力より　３　ｄＢ低下するまでの走行回
数を測定して行ない、耐食性試験は得られ磁気テープを
６０℃９０％ＲＨの条件下に放置し、所定の期間毎に最
大磁束密度を測定して行なった。Comparative Example 5> Formation of the V AGH resin layer in Example 1 and
The procedure was the same as in Example 1 except that the application of the KRYTOX157F solution and the drying process were omitted.The durability and corrosion resistance of the magnetic tapes obtained in each example and comparative example were tested.The durability test was conducted at 25°C and 60°C. %
Under RH condition, head load 59 running speed 0.048r
A corrosion resistance test was performed by running and playing the magnetic tape obtained with n/ace and measuring the number of runs until the output decreased by 3 dB from the initial output. The maximum magnetic flux density was measured at predetermined intervals.

なお測定値は放置前の磁気テープの最大磁束密度を１０
０％とし、これと比較した値で表わした。The measured values are based on the maximum magnetic flux density of the magnetic tape before being left unused.
0% and expressed as a value compared to this.

下表はその結果である。The table below shows the results.

上表の結果から明らかなように、この発明で得られた磁
気テープは従来の磁気テープに比べ、耐久性、耐食性共
にすぐれているものであることがわかる。As is clear from the results in the table above, it can be seen that the magnetic tape obtained by the present invention has superior durability and corrosion resistance compared to conventional magnetic tapes.

出願人　日立マクセル株式会社 代表者　永　井　厚Applicant: Hitachi Maxell, Ltd. Representative Atsushi Nagai

Claims (1)

【特許請求の範囲】 （１）非磁化性基体上に形成された金属磁性薄膜よ構成
る記録層上に、樹脂層を形成し、さらにこの樹脂層上に
、分子末端にカルボキシル基を有するパーフルオロポリ
エーテルを被着したことを特徴とする金属磁性薄膜記録
媒体。 Ｔ２＋　ｌ１ｌｌ記パーフルオロポリエーテルが一般式
％式％ ） で表現されることを特徴とする特許請求の範囲第（１１
項記載の金属磁性薄膜記録媒体。 （３）前記樹脂層が塩化ビニル−酢酸ビニル系樹脂、セ
ルロース系樹脂、フチラール樹脂、メチルメタアクリレ
ート、及びスチレン共重合体により構成される群よｐ選
択される少なくとも１種の樹脂よ多構成されることを特
徴とする特許請求の範囲第（１）項記載の金属磁性薄膜
記録媒体。 （４１ｎ記構脂層が１μ以下の膜厚を有し、かつ前記パ
ーフルオロポリエーテルが、樹脂層表面に対し０．０１
〜１００■／ｒｌの被着量であることを特徴とする特許
請求の範囲第（１）項記載の金属磁性薄膜記録媒体。[Scope of Claims] (1) A resin layer is formed on a recording layer composed of a metal magnetic thin film formed on a non-magnetic substrate, and a resin layer is further formed on the resin layer, and a permeable resin having a carboxyl group at the molecular end is formed. A metal magnetic thin film recording medium characterized by being coated with fluoropolyether. Claim No. 11, characterized in that the perfluoropolyether T2+ is expressed by the general formula %.
The metal magnetic thin film recording medium described in . (3) The resin layer is composed of at least one resin selected from the group consisting of vinyl chloride-vinyl acetate resin, cellulose resin, phthyral resin, methyl methacrylate, and styrene copolymer. A metal magnetic thin film recording medium according to claim (1). (41n) The structural resin layer has a thickness of 1μ or less, and the perfluoropolyether has a thickness of 0.01μ or less with respect to the surface of the resin layer.
The metal magnetic thin film recording medium according to claim (1), characterized in that the coating amount is 100 .mu./rl.