JPS60131627A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a protective layer on the rear surface having sufficient abrasion resistance and improved running stability by forming the protective layer contg. an oranic sulfur compd. on the surface of a magnetic supporting body opposed to the magnetic metallic thin film forming surface. CONSTITUTION:A protective layer is obtained on the rear surface by coating an organic sulfur compd. having specified structure along with a biner. An unsaturated sulfide, a cyclic sulfide, an epithio compd., and a diepithio compd. among others are preferably used as the organic sulfur compd. A thermoplastic or a thermosetting resin which is commonly used for forming a magnetic layer of a coating-type magnetic recording medium such as a vinyl chloride-vinyl acetate or its partially saponified substance, a vinyl chloride-vinyl acetate-maleic acid copolymer, nitrocellulose, a polyurethane elastomer, a polyester resin, an epoxy resin, and an acrylic resin is used for the rear surface protective layer. Nemely, 5-30pts. organic sulfur compd. is added to 10pts. binder consisting of a mixture of one or >=2 kinds among said resins, and coated along with a suitable solvent on the rear surface of a supporting body to obtain the rear surface protective layer. The rear surface protective layer can be formed before or after the surface magnetic layer is forfmed. The thickness of the rear surface protective layer is preferably regulated to 0.5-3mum, for example.

Description

【発明の詳細な説明】 本発明は、磁性体として強磁性金属薄膜を用いる、いわ
ゆる蒸着型のメタルテープの改良に関し、特に、非磁性
支持体シートの磁性膜形成面とは逆側の面に保護層を形
成して走行性を改善した金属薄膜型の磁気記録媒体に関
する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the improvement of a so-called vapor-deposited metal tape that uses a ferromagnetic metal thin film as a magnetic material, and particularly to the improvement of a so-called vapor-deposited metal tape that uses a ferromagnetic metal thin film as a magnetic material. The present invention relates to a metal thin film type magnetic recording medium in which running properties are improved by forming a protective layer.

従来より、通常はポリエステルフィルムないしはシート
等の非磁性支持体上に、スパッタリング等による強磁性
金属薄膜を形成してなるいわゆる蒸着型のメタルテープ
は、強磁性粉末をバインダー中に分散させ、塗布してな
る塗布型のテープに比べて、磁性層中に充填剤を含まな
いため、残留磁束密度（Ｂｒ）等の磁気特性に優れてお
り、近年、特に注目されでいる□。Conventionally, so-called vapor-deposited metal tapes, which are made by forming a thin ferromagnetic metal film by sputtering or the like on a non-magnetic support such as a polyester film or sheet, are made by dispersing ferromagnetic powder in a binder and coating it. Since it does not contain a filler in the magnetic layer, it has superior magnetic properties such as residual magnetic flux density (Br), and has attracted particular attention in recent years.

しかしながら、このような蒸着テープは、その磁性膜が
木質°的に強磁性合金を主体とするため、機械的には非
常に硬くな葛という問題があり、このため、磁性層表面
の粗さと相俟って、磁気ヘッドを急速に摩耗させる点な
らびに走行安定性等に欠点があった。However, since the magnetic film of this type of vapor-deposited tape is mainly made of a ferromagnetic alloy, it has the problem of being extremely hard mechanically. However, there were drawbacks such as rapid wear of the magnetic head and poor running stability.

牡に、蒸着法により磁性薄膜を形成するときは、非磁性
支持体の表面形状粗さに沿って金属粒子がイ十着し成膜
されるた″め、表面が平滑で間隙損失の少ない、したが
って磁気特性の安定した磁性薄膜を得るためには、非議
性支持体、すなわちベースフィル゛ムｉ体の表面粗さを
小さくする必要がある。Secondly, when forming a magnetic thin film by vapor deposition, the metal particles are deposited along the roughness of the surface of the non-magnetic support, resulting in a smooth surface with little gap loss. Therefore, in order to obtain a magnetic thin film with stable magnetic properties, it is necessary to reduce the surface roughness of the asymmetric support, that is, the base film.

このようにして磁性層表面側は磁気特性的に良好な結果
が得られたとしても、支持体裏面においては、却って表
面が平滑であるが故にテープ走行時に、いわゆるテープ
の貼り付き現象が起り、走行安定性が欠けるという欠点
が生じていた。In this way, even if good results are obtained in terms of magnetic properties on the front side of the magnetic layer, the back side of the support has a smooth surface, so when the tape runs, a so-called tape sticking phenomenon occurs. The drawback was a lack of running stability.

このような欠点を除き、走行性を改善するために従来の
蒸着型テープにおいては、支持体の裏面に、いわゆるバ
ックコートとして、例えばＣｒ２Ｏ３、Ａ　１２ｏ、！
？、−は５ｉ０２等の無機砥粒を結合剤とともに塗布す
ること、あるいは高級脂肪酸またはそのエステル、シリ
コーン系樹脂、パラフィンワックス等の有機系潤滑剤を
結合剤とともに塗布することが行なわれている。In order to eliminate these drawbacks and improve running properties, conventional vapor-deposited tapes coat the back side of the support with a so-called back coat of, for example, Cr2O3, A12O,!
? , - is carried out by applying inorganic abrasive grains such as 5i02 together with a binder, or by applying an organic lubricant such as a higher fatty acid or its ester, a silicone resin, or paraffin wax together with a binder.

こあうち、無機□砥粒を結合剤とともに塗布する方法は
、ガイドビン等への摩耗が大きいほかに、重ね巻きにし
た場合、磁性薄膜を傷付ける場合がある。他方、有機系
の潤滑剤を使用する方法は、無機砥粒を使用するものに
比べて、塗布が容易で、薄層形成も容易であるという利
点は有るものの、走行性の改善に充分な効果が得られな
いという問題がある。すなわち、従来から使用されてい
る有機潤滑剤は、比較的低分子量であり、可塑化効果も
大きいため、充分な貼付き防止効果を発揮させるほどに
これを添加した裏面層は、摩耗耐久性が不充分となる。However, the method of applying inorganic □ abrasive grains together with a binder not only causes a lot of wear on guide bottles, etc., but also may damage the magnetic thin film when wound in layers. On the other hand, methods using organic lubricants have the advantage of being easier to apply and forming a thin layer than those using inorganic abrasive grains, but they are not sufficiently effective in improving running performance. The problem is that it cannot be obtained. In other words, conventionally used organic lubricants have a relatively low molecular weight and have a large plasticizing effect, so a back layer containing enough lubricants to exhibit sufficient anti-sticking effects has poor wear durability. It becomes insufficient.

このため、充分な量の呼加ができず、したがって不充分
な走行性改善効果しか得られなかった。For this reason, a sufficient amount of additive could not be added, and therefore only an insufficient effect of improving running performance could be obtained.

本発明の目的は、特定の有機系潤滑剤を添加することに
より、充分な耐摩耗性と走行安定性改善効果を示す裏面
保護層を有する金属薄膜型の磁気記録媒体を提供するこ
とにある。An object of the present invention is to provide a metal thin film type magnetic recording medium having a back protective layer that exhibits sufficient wear resistance and running stability improvement effects by adding a specific organic lubricant.

本発明渚等の研究によれば、特定の構造の有機イオウ化
合物を結合剤とともに塗布して裏面保護層とすることが
、上述の目的の達成のために効果的であることが見出さ
れた。According to research by Nagisa et al., it was found that applying an organic sulfur compound with a specific structure together with a binder to form a backside protective layer is effective for achieving the above-mentioned purpose. .

本発明の磁気記録媒体は、このような知見に基づくもの
であり、より詳しく−は、非磁性支持体シート上に、金
属磁性薄膜が形成されてなる磁気記録媒体において、上
記非磁性支持体シートの金属磁性薄膜形成面とは逆側の
面に壱機イオウ化合物を含む保護層を形成してなること
を特徴とするものである。The magnetic recording medium of the present invention is based on such knowledge, and more specifically, in a magnetic recording medium in which a metal magnetic thin film is formed on a non-magnetic support sheet, the magnetic recording medium is based on the above-mentioned non-magnetic support sheet. A protective layer containing a sulfur compound is formed on the surface opposite to the surface on which the metal magnetic thin film is formed.

以下、本発明を更に詳細に説明する。以下の記載におい
て組成を表わす「％」および「部」は特に断らない限り
重量基準とする。The present invention will be explained in more detail below. In the following description, "%" and "part" indicating composition are based on weight unless otherwise specified.

本発明の磁気記録媒体の構成は、裏面に上記した有機イ
オウ化合−物を含む保護層を設けることを除けば、従来
の金属薄膜型磁気記録媒体のそれと特に異るものではな
い。すなわち、本発明の磁気記録媒体は、基本的には、
非磁性支持体上に、強磁性全屈薄膜を形成してなる。The structure of the magnetic recording medium of the present invention is not particularly different from that of a conventional metal thin film type magnetic recording medium, except that a protective layer containing the above-mentioned organic sulfur compound is provided on the back surface. That is, the magnetic recording medium of the present invention basically has the following features:
It consists of a ferromagnetic fully refracting thin film formed on a nonmagnetic support.

非磁性支持体としては、通常、ポリエチレンテレフタレ
ート、ポリカーボネート、ポリアセテート、ポリアミド
、ポリイミド、などの比較的耐熱性の良好なプラスチッ
クの厚さ３〜２０ＩＬ程度のフィルムが好ましく用いら
れるが、その他非磁性金属箔なども必要に応じて用いる
ことができ、基本的には、所望の平滑な磁性層形成面と
裏面を有する任意のシー）・状ないしフィルム状固体材
料が用いられる。As the non-magnetic support, a film with a thickness of about 3 to 20 IL made of relatively heat-resistant plastic such as polyethylene terephthalate, polycarbonate, polyacetate, polyamide, polyimide, etc. is preferably used, but other non-magnetic metals are also used. Foil or the like may be used if necessary, and basically any sheet-like or film-like solid material having a desired smooth magnetic layer forming surface and back surface can be used.

磁性層は、上記したような非磁性支持体」二に、必要に
応じて、コロナ処理、プライマー処理などの接着強化処
理を行ったのち、一般にスパッタリング等の蒸着により
、Ｆｅ、Ｃｏ、Ｎｉ等を主成分とする強磁性合金の、厚
さが０．０５〜０．５川の薄膜を形成することにより得
られる。The magnetic layer is generally formed by depositing Fe, Co, Ni, etc. on the non-magnetic support described above, after performing adhesion strengthening treatment such as corona treatment and primer treatment as necessary. It is obtained by forming a thin film with a thickness of 0.05 to 0.5 mm of a ferromagnetic alloy as the main component.

一方、本発明の特徴とする保護層は、支持体の裏面に有
機イオウ化合物を含む塗布層として期成されるものであ
る。有機イオウ化合物としては、特に不飽和スルフィド
、環状スルフィド、エピチオ化合物またはジェピチオ化
合物が好ましく、なかでも下記の式ないしは一般式で表
わされるものが好ましく用いられる。On the other hand, the protective layer that characterizes the present invention is formed as a coating layer containing an organic sulfur compound on the back surface of the support. The organic sulfur compound is particularly preferably an unsaturated sulfide, a cyclic sulfide, an epithio compound or a jepithio compound, and among them, those represented by the following formula or general formula are preferably used.

ｅ・・・・ｅ拳（１） （Ｘは１または２．′　ｎは１〜ｌＯ）ＣＨ。e...e fist (1) (X is 1 or 2.' n is 1 to 1O) CH.

１ 裏面保護層は、たとえば塩化ビニル−酢酸ビニル共重合
体あるいはその部分ケン化物、用孔ビニルー酢酸ビニル
ーマレイン酸共重合体、ニトロセルロース、ポリウレタ
ンエラストマー、ポリエステル樹脂、エポキシ樹脂、ア
クリル樹脂などの一般に塗布型磁気記録媒体の磁性層形
成に用いられる熱ｎｆ　ｔｆｆｊ性あるいは熱硬化性樹
脂の一種又は二種以上の混合物からなるパイングー１０
０部に対し、上記したような有機イオウ化合物を５〜３
０部程度婚加して、適当な溶剤とともに支持体の裏面に
塗布することにより得られる。この裏面像Ｗｋ層の形成
は、表面磁性層の形成の前でも、後でもよい。裏面保護
層の厚さは１例えば０．５〜３ｇｍ程度でよい。1 The back protective layer is generally made of vinyl chloride-vinyl acetate copolymer or a partially saponified product thereof, perforated vinyl-vinyl acetate-maleic acid copolymer, nitrocellulose, polyurethane elastomer, polyester resin, epoxy resin, acrylic resin, etc. Pine Goo 10, which is made of one or a mixture of two or more of thermal nf tffj or thermosetting resins used for forming the magnetic layer of coated magnetic recording media.
0 parts, 5 to 3 parts of organic sulfur compounds as described above
It can be obtained by adding about 0 parts of the mixture and coating it on the back side of a support together with a suitable solvent. This back surface image Wk layer may be formed before or after the formation of the surface magnetic layer. The thickness of the back surface protective layer may be about 1, for example, 0.5 to 3 gm.

上記したように本発明によれば、特定の構造の有機イオ
ウ化合物を含み、充分な耐摩耗性と走行安定性改善効果
を示す裏面保ＡｆＣ層を有する金属薄膜型の磁気記録媒
体が得られる。As described above, according to the present invention, it is possible to obtain a metal thin film type magnetic recording medium having a back surface protective AfC layer containing an organic sulfur compound having a specific structure and exhibiting sufficient wear resistance and running stability improvement effects.

以下、実施例、比較例により本発明を更に具体的に説明
する。Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

支ｊ口Ｉ」 厚さ約１２ｊＬｍのポリエステルフィルムの一面に、公
知の蒸着装置を用いて、Ｃｏ８０％、Ｎｉ２Ｏ％の組成
を有する厚さ約０　、１　ＪＬｍの強磁性金属薄膜を形
成し、更に、酸化防止処理を施こした。A ferromagnetic metal thin film with a thickness of about 0.1 JLm having a composition of 80% Co and 20% Ni is formed on one side of a polyester film with a thickness of about 12JLm using a known vapor deposition apparatus, and , treated with anti-oxidation treatment.

次いで、上記ポリエステルフィルムの磁性薄膜形成面と
は逆の面（すなわち裏面）に、結合剤（ポリエステル樹
脂（平均分子量　２００００））１００部に対して、有
機イオウ化合物として、前記式（１）で表わされる不飽
和ジスルフィド５部を添加した保護層を、約１μｍの厚
さに塗布、形成して１本発明による磁気テープを得た。Next, on the opposite side of the polyester film from the side on which the magnetic thin film was formed (i.e., the back side), an organic sulfur compound represented by the formula (1) was added to 100 parts of the binder (polyester resin (average molecular weight 20,000)). A magnetic tape according to the present invention was obtained by coating and forming a protective layer containing 5 parts of unsaturated disulfide in a thickness of about 1 μm.

え豊１」 有機イオウ化合物として、前記式（２）（但し、Ｘ＝２
、ｎ＝２）で表わされる不飽和スルフィド５部を用いる
以外は、実施例１と同様にして磁気テープを得た。Eho 1'' As the organic sulfur compound, the above formula (2) (however, X = 2
A magnetic tape was obtained in the same manner as in Example 1, except that 5 parts of unsaturated sulfide represented by , n = 2) was used.

支１１」 有機イオウ化合物として、前記式（３）（但し、Ｘ＝２
、ｙ＝２）で表わされる不飽和スルフィド５部を用いる
以外は、実施例１と同様にして磁気テープを得た。Support 11'' As the organic sulfur compound, the above formula (3) (where X = 2
A magnetic tape was obtained in the same manner as in Example 1, except that 5 parts of unsaturated sulfide represented by , y=2) was used.

支ｌ狙」 有機イ才つ化合物として、前記式（４）で表わされる環
状スルフィド５部を用いる以外は、実施例１と同様にし
て８１気テープを得た。An 81x tape was obtained in the same manner as in Example 1, except that 5 parts of the cyclic sulfide represented by the formula (4) above was used as the organic compound.

支基皇」 有機イオウ化合物として、前記式（５）（但し、ｘ＝１
４、ｙ：＝２）で表わされるエピチオ化合物５部を用い
る以外は、実施例１と同様にして磁気テープを得た。As the organic sulfur compound, the formula (5) (where x=1
A magnetic tape was obtained in the same manner as in Example 1, except that 5 parts of the epithio compound represented by 4,y:=2) was used.

支ｌ貰」 有機イオウ化合物として、前記式（６）で表わされる不
飽和スルフィド５部を用いる以外は、実施例１と同様に
して磁気テープを得た。A magnetic tape was obtained in the same manner as in Example 1, except that 5 parts of unsaturated sulfide represented by the above formula (6) was used as the organic sulfur compound.

ル敢皇」 実施例１において、裏面保ｉ＆層を形成しない以外は、
同様にして磁気テープを得た。In Example 1, except that the back surface protection layer was not formed,
A magnetic tape was obtained in the same manner.

ル笠扁」 有機イオウ化合物の代わりに、ブチルステアレート約５
部を用いる以外は、実施例１と同様にして磁気テープを
得た。Butyl stearate instead of organic sulfur compounds
A magnetic tape was obtained in the same manner as in Example 1, except that

上記の実施例１〜６および比較例１．２で得られた磁気
テープにつき走行安定性を調べるためにイ）ジッターの
測定（松下製ＶＴＲＮＶ−８００使用）および 口）一定時間（５０時間）のテープ走行後のテープ裏面
に接触するステンレス製ガイドポストのキズの状態の観
察 を行なった。In order to investigate the running stability of the magnetic tapes obtained in Examples 1 to 6 and Comparative Example 1.2, a) measurement of jitter (using Matsushita VTRNV-800) and After the tape ran, the state of the scratches on the stainless steel guide post that came into contact with the back surface of the tape was observed.

結果をまとめて次表に示す。The results are summarized in the table below.

但し、次表において、ガイドポストの傷の確認は目視に
より行ない、その判定基準は以下の通りである。However, in the table below, the damage on the guide post is checked visually, and the criteria are as follows.

Ｏ・・・殆んど傷がない。O... There are almost no scratches.

Δ・・・細い傷が確認される。Δ...Thin scratches are confirmed.

×・・・大きい傷が確認される。×...A large scratch is confirmed.

上表の結果を見れば明らかな通り５本発明の有機イオウ
化合物を含む裏面保護層を有する蒸Ｚｉ型の磁気テープ
は、裏面保護層を設けない磁気テープ（比較例１）なら
びに従来の有機潤滑剤を含む裏面保護層を有する磁気テ
ープに比べて、ジッターならびにガイドポストの損傷の
いずれの点からみても走行性が改善されている。As is clear from the results in the table above, the evaporated Zi type magnetic tape with the back protective layer containing the organic sulfur compound of the present invention is different from the magnetic tape without the back protective layer (Comparative Example 1) and the conventional organic lubricant. Compared to a magnetic tape having a backside protective layer containing an agent, running properties are improved in terms of both jitter and damage to guide posts.

Claims (1)

【特許請求の範囲】 １、非磁性支持体シート上に、金属磁性薄膜が形成され
てなる磁気記録媒体において、上記非磁性支持体シート
の金属磁性薄膜形成面とは逆側の面に有機イオウ化合物
を含む保ｉｆ層を形成してなることを特徴とする磁気記
録媒体。 ２、上記有機イオウ化合物が、不飽和スルフィド、環状
スルフィド、エピチオ化合物およびジエピチオ化合物よ
り選ばれる特許請求の範囲第１項の磁気記録媒体。[Claims] 1. In a magnetic recording medium in which a metal magnetic thin film is formed on a non-magnetic support sheet, an organic sulfur layer is provided on the surface of the non-magnetic support sheet opposite to the surface on which the metal magnetic thin film is formed. A magnetic recording medium comprising a retention layer containing a compound. 2. The magnetic recording medium according to claim 1, wherein the organic sulfur compound is selected from unsaturated sulfides, cyclic sulfides, epithio compounds, and diethio compounds.