JPH02141920A - Magnetic recording medium - Google Patents
Magnetic recording mediumInfo
- Publication number
- JPH02141920A JPH02141920A JP29491688A JP29491688A JPH02141920A JP H02141920 A JPH02141920 A JP H02141920A JP 29491688 A JP29491688 A JP 29491688A JP 29491688 A JP29491688 A JP 29491688A JP H02141920 A JPH02141920 A JP H02141920A
- Authority
- JP
- Japan
- Prior art keywords
- film
- carbon black
- magnetic recording
- recording medium
- thin film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000005291 magnetic effect Effects 0.000 title claims abstract description 18
- 239000006229 carbon black Substances 0.000 claims abstract description 14
- 229920006254 polymer film Polymers 0.000 claims abstract description 11
- 239000000956 alloy Substances 0.000 claims description 2
- 229910045601 alloy Inorganic materials 0.000 claims description 2
- 239000010408 film Substances 0.000 abstract description 25
- 239000010409 thin film Substances 0.000 abstract description 11
- 230000015572 biosynthetic process Effects 0.000 abstract description 2
- 239000002245 particle Substances 0.000 abstract description 2
- 229910000531 Co alloy Inorganic materials 0.000 abstract 2
- 230000015556 catabolic process Effects 0.000 abstract 1
- 238000006731 degradation reaction Methods 0.000 abstract 1
- 238000010348 incorporation Methods 0.000 abstract 1
- -1 polyethylene terephthalate Polymers 0.000 description 8
- 239000010410 layer Substances 0.000 description 6
- 230000005415 magnetization Effects 0.000 description 6
- 239000010702 perfluoropolyether Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 229920000139 polyethylene terephthalate Polymers 0.000 description 5
- 239000005020 polyethylene terephthalate Substances 0.000 description 5
- 238000004544 sputter deposition Methods 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 235000014113 dietary fatty acids Nutrition 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229930195729 fatty acid Natural products 0.000 description 4
- 239000000194 fatty acid Substances 0.000 description 4
- 230000005294 ferromagnetic effect Effects 0.000 description 4
- 239000000314 lubricant Substances 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 241000872198 Serjania polyphylla Species 0.000 description 3
- 238000005566 electron beam evaporation Methods 0.000 description 3
- 150000004665 fatty acids Chemical class 0.000 description 3
- 229920006290 polyethylene naphthalate film Polymers 0.000 description 3
- 239000004721 Polyphenylene oxide Substances 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 229920000570 polyether Polymers 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 229910052707 ruthenium Inorganic materials 0.000 description 2
- 229910020632 Co Mn Inorganic materials 0.000 description 1
- 229910020630 Co Ni Inorganic materials 0.000 description 1
- 229910002440 Co–Ni Inorganic materials 0.000 description 1
- 229910020678 Co—Mn Inorganic materials 0.000 description 1
- 239000004734 Polyphenylene sulfide Substances 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000001017 electron-beam sputter deposition Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- RTZKZFJDLAIYFH-UHFFFAOYSA-N ether Substances CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229920000069 polyphenylene sulfide Polymers 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2261/00—Macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain of the macromolecule
- C08G2261/30—Monomer units or repeat units incorporating structural elements in the main chain
- C08G2261/31—Monomer units or repeat units incorporating structural elements in the main chain incorporating aromatic structural elements in the main chain
- C08G2261/312—Non-condensed aromatic systems, e.g. benzene
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、高密度磁気記録に適する強磁性金属薄膜を磁
気記録層とする磁気記録媒体に関する。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium whose magnetic recording layer is a ferromagnetic metal thin film suitable for high-density magnetic recording.
従来の技術
記録、再生機器の小型化、高性能化の為に記録密度向上
の努力は継続的に行われておシ、最近では強磁性金属薄
膜を磁気記録層として実用化することが待望されるに至
っている〔アイイーイーイトランザクションズ オン
マグネティクス（ＩＥＥＥ ＴＲＡＮＳＡＣＴＩＯＮＳ
ＯＮＭＡＧＮＥＴＩＣ３）Ｖｏｇ、 ＭＡＧ−２１、
Ｊ！；、−３，Ｐ、Ｐ、 １２１７−１２２０（１９８
５））。強磁性金属薄膜は材料としての組合わせは多数
考えられるが、現実的な可能性が示されているものは少
く、Ｃｏ−Ｃｒ等の垂直磁化膜〔特公昭６Ｂ−９１号公
報、特開昭６１−１２０３３１号公報〕やＣｏ−Ｎｉ、
Ｃｏ−Ｎｉ−０等の斜め蒸着嘆や湿式めっき模〔特公昭
４１−１９３８９号公報。Conventional technology Efforts to improve recording density have been made continuously in order to miniaturize and improve the performance of recording and reproducing equipment, and recently there has been a long-awaited desire to put ferromagnetic metal thin films into practical use as magnetic recording layers. [IEE Transactions on
Magnetics (IEEE TRANSACTIONS)
ONMAGNETIC3)Vog, MAG-21,
J! ;, -3, P, P, 1217-1220 (198
5)). There are many possible combinations of materials for ferromagnetic metal thin films, but only a few have been shown to have realistic possibilities. 61-120331], Co-Ni,
Oblique vapor deposition or wet plating of Co-Ni-0 etc. [Japanese Patent Publication No. 19389/1989].
特開昭５３−４２０１０号公報〕等で、実用化の目的で
最近ではもっばら、保護潤滑層の開発が検討の中心とな
っている。現状ではポリエチレンテレフタレートフィル
ム等の高分子フィルム上に直接あるいは微粒子などの下
塗υを行った後、電子ビーム蒸着法やスパッタリング法
で強磁性金属薄膜を配し、その面に直接溶剤に脂肪酸や
パーフルオロポリエーテル等の潤滑剤を溶かした溶液を
塗布乾燥する法〔特開昭５７−１７９９４８号公報。JP-A No. 53-42010] and other publications, the development of a protective lubricant layer has recently become the focus of attention for the purpose of practical application. Currently, a ferromagnetic metal thin film is deposited directly on a polymer film such as a polyethylene terephthalate film or after applying an undercoat such as fine particles, using an electron beam evaporation method or sputtering method. A method in which a solution containing a lubricant such as polyether is applied and dried [JP-A-57-179948.
特開昭６１−１７８７１８号公報〕や、酸化嘆を介して
潤滑剤を配する〔特開昭６１−１５１８３０号公報〕こ
とや、炭素模と７０ロカーボン系の組み合わせ〔特開昭
６１−１４２５２５号公報〕等が提案され、磁気ディス
クではまだ炭素模が厚いとはいうものの一部実用化され
、炭素質についても検討が進み硬度を高めることの有用
性〔米国特許４７１７６２２号明細書〕も知られるに至
っている。JP-A-61-178718], applying lubricant through oxidation [JP-A-61-151830], and combination of carbon model and 70 carbon system [JP-A-61-142525]. Publications], etc. have been proposed, and some magnetic disks have been put into practical use, although the carbon pattern is still thick, and carbon materials have also been studied, and the usefulness of increasing hardness [US Pat. No. 4,717,622] is also known. It has reached this point.
発明が解決しようとする課題
しかしながら、Ｃｏ−Ｃｒ 、Ｃｏ−Ｒｕ 、Ｃｏ −
Ｔ ｉ 等の垂直磁化膜を高分子フィルムや高分子フ
ィルム上に微粒子塗布層を配した上に電子ビーム蒸着法
やスパッタリング法で形成したものは、薄膜の形成初期
層の結晶性が悪く、電磁変換特性を改善するには模厚が
大きくなり、高速な回転磁気ヘッドとの摺接の安定性が
確保しにくい為、目標の高密度記録性能が得られないと
いった課題があシ改善が望まれていた。Problems to be Solved by the Invention However, Co-Cr, Co-Ru, Co-
When a perpendicularly magnetized film such as Ti is formed by electron beam evaporation or sputtering on a polymer film or a fine particle coating layer on a polymer film, the initial layer of the thin film has poor crystallinity and is electromagnetic. In order to improve the conversion characteristics, the thickness must be increased, and it is difficult to ensure stable sliding contact with a high-speed rotating magnetic head, so the target high-density recording performance cannot be achieved.Improvement is desired. was.
本発明は上記した事情に鑑みなされたもので、ヘッドタ
ッチの良好な磁気記録媒体を提供するものである。The present invention was made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a magnetic recording medium with good head touch.
課題を解決するための手段
本発明の磁気記録媒体は上記した課題を解決するためカ
ーボンブラックを混入した高分子フィルム上に直接Ｃｏ
系合金垂直磁化膜を配したものである。Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention directly coats a polymer film containing carbon black.
A perpendicularly magnetized alloy film is arranged.
作 用
本発明の磁気記録媒体は上記した構成により、カーボン
ブラックを核にして形成される表面凹凸は急しゅんでな
いため、薄膜の初期成長に生じる結晶性の悪化は少なく
、膜厚増は最小におさえられるのと、カーボンブラック
混入によシ、高分子フィルムの剛性も大きくなり、高速
での回転ヘッドとのタッチが確実になるのと、薄膜形成
時に。Function: Due to the above-described structure of the magnetic recording medium of the present invention, the surface irregularities formed with carbon black as the core are not sudden, so there is little deterioration of crystallinity that occurs during the initial growth of the thin film, and the increase in film thickness is minimized. In addition, the rigidity of the polymer film increases due to the presence of carbon black, and the contact with the rotating head at high speed is ensured during thin film formation.
フィルムの熱伝導度、電気伝導度が改善されていること
から、荷電粒子が薄膜に生じる不均一性も殆んどみられ
ず、雑音もよいレベルとなることから高密度記録性能を
満たせることになる。Because the thermal conductivity and electrical conductivity of the film have been improved, there is almost no non-uniformity caused by charged particles in the thin film, and the noise is at a good level, making it possible to meet high-density recording performance. Become.
実施例
以下、図面を参照しながら本発明の実施例について説明
する。図は本発明の実施例の磁気記録媒体の拡大断面図
である。図で１は、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、ホリエーテル
エーテルクトン、ポリフェニレンサルファイド等の高分
子フィルムで、直径４００人から２０ｏＯ人のカーボン
ブラック２を６重量％から２０重量％含むよう構成した
ものである。５重量％以下では、雑音改善効果やヘッド
タッチの改善効果が弱まり、２ＯＮ量チ以下では表面が
粗くなりすぎて、スペ二シング損失が増えて高密度記録
性能が損われることからこの範囲が好ましい。３はＣｏ
−０ｒ 、Ｃｏ−Ｔａ 、Ｃｏ−’ｒｔ 。Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. The figure is an enlarged sectional view of a magnetic recording medium according to an embodiment of the present invention. In the figure, 1 is a polymer film such as polyethylene terephthalate film, polyethylene naphthalate film, polyether ether lactone, polyphenylene sulfide, etc., and is composed of a carbon black 2 with a diameter of 400 to 2000 mm containing 6% to 20% by weight. It is something. If it is less than 5% by weight, the noise improvement effect and head touch improvement effect will be weakened, and if it is less than 2ON, the surface will become too rough, increasing spacing loss and impairing high-density recording performance, so this range is preferable. . 3 is Co
-0r, Co-Ta, Co-'rt.
Ｃｏ −Ｍｏ 、 Ｃｏ −Ｍｎ 、 Ｇｏ −Ｗ 、
Ｇ ｏ−Ｒｕ 、 Ｃｏ −Ｃｒ −Ｎｂ 。Co-Mo, Co-Mn, Go-W,
Go-Ru, Co-Cr-Nb.
Ｇｏ−Ｃｒ−Ｒｈ等の垂直磁化膜で電子ビーム蒸着法。Electron beam evaporation method using a perpendicularly magnetized film such as Go-Cr-Rh.
イオンブレーティング法、スパッタリング法等で形成さ
れる。４は保護潤滑層で、プラズマ重合模。It is formed by an ion blasting method, a sputtering method, or the like. 4 is a protective lubricant layer, which is a plasma polymerized layer.
酸化膜、カーボン模、脂肪酸、脂肪酸アミド、脂肪酸エ
ステル、硫黄化脂肪酸、パーフルオロポリエーテル、高
級アルキルスルホン酸２等から一種又はそれ以上が用い
られる。One or more of the following may be used: oxide film, carbon pattern, fatty acid, fatty acid amide, fatty acid ester, sulfurized fatty acid, perfluoropolyether, higher alkyl sulfonic acid 2, etc.
以下、更に具体的に本発明の実施例について比較例との
対比で説明する。Examples of the present invention will now be described in more detail in comparison with comparative examples.
〔実施例−１〕
厚み１０μｍのポリエチレンナフタレートフィルムで、
直径８００人のカーボンブラックを１０重量％含み、表
面粗さが平均粗さで８０へのフィルムを用い、高周波ス
パッタリング法でＣｏ−Ｃｒ垂直磁化膜を１６００Ａ形
成した。Ｃｏ−０ｒ（Ｃｏ：８０ｗｔ％）膜の垂直保磁
力は９０５（Ｏｓ）である。[Example-1] A polyethylene naphthalate film with a thickness of 10 μm,
Using a film containing 10% by weight of carbon black with a diameter of 800 mm and an average surface roughness of 80 mm, a Co--Cr perpendicular magnetization film of 1600 Å was formed by high-frequency sputtering. The vertical coercive force of the Co-0r (Co: 80 wt%) film is 905 (Os).
Ｃｏ−Ｃｒ上にパーフルオロポリエーテルとして市販の
モンテフルオス社製の“フオンプリンｚ−２６”を３ｍ
ｇ７ｒｒｚ配し８ミリテープとした。3 m of “Fuonpurin Z-26” manufactured by Montefluos, a commercially available perfluoropolyether, was deposited on Co-Cr.
It was an 8 mm tape with g7rrz arrangement.
〔実施例−２〕
厚み１０μｍのポリエチレンテレフタレートフィルムで
直径１０００人のカーボンブラックを１７重量％含み、
平均粗さ１００人のフィルムを用い、電子ビーム蒸着法
で入射角９度以内でＣｏ −Ｃｒ（Ｃｏ ： ８０ｗｔ
％ ）を蒸着し、１６００人で９００（Ｏｅ）の垂直磁
化膜を形成し、その上に実施例−１と同じパーフルオロ
ポリエーテルを配し８ミリテープとした。[Example-2] A polyethylene terephthalate film with a thickness of 10 μm containing 17% by weight of carbon black with a diameter of 1000 mm,
Using a film with an average roughness of 100, Co-Cr (Co: 80 wt.
%) to form a perpendicular magnetization film of 900 (Oe) using 1,600 people, and the same perfluoropolyether as in Example 1 was placed thereon to form an 8 mm tape.
〔実施例−３〕
厚ミ１０７〕ｍのポリエチレンテレフタレートフィルム
で直径６００Ａのカーボンブラックを１５重量％含み、
平均粗さ９０人のフィルムを用い、高周波スパッタリン
グ法でＣｏ−Ｃｒ−Ｎｂ［Ｃｏ：Ｃｒ：Ｎｂ＝７９：１
６：５ｗｔ％〕垂直磁化模を１４００（Ａ）。[Example-3] A polyethylene terephthalate film with a thickness of 107 m and containing 15% by weight of carbon black with a diameter of 600 A,
Co-Cr-Nb [Co:Cr:Nb=79:1] was prepared by high-frequency sputtering using a film with an average roughness of 90.
6:5wt%] Perpendicular magnetization model is 1400 (A).
保磁力９１０ （Ｏｅ）で形成した上に実施例−１と同
じパーフルオロポリエーテルを配し８ミリテープとした
。A tape having a coercive force of 910 (Oe) was coated with the same perfluoropolyether as in Example 1 to obtain an 8 mm tape.
〔比較例−１〕
厚み１０μｍのポリエチレンテレフタレートフィルム（
平均粗さ２０人）上に直径８０ＡのＣｒ２Ｏ３微粒子を
２０ケ／（μｍ）２配し、高周波スパッタリング法によ
シ、Ｃｏ −Ｃｒ （Ｃｏ ： ８０ｗｔ％）とＣｏ−
Ｃｒ −Ｎｂ （Ｃｏ ：Ｃｒ ：Ｎｂ＝７９ ：１６
：５ｗｔ％）垂直磁化膜を形成し、実施例−１と同じ
パーフルオロポリエーテルを配し８ミリテープとした。[Comparative Example-1] Polyethylene terephthalate film with a thickness of 10 μm (
Co-Cr (Co: 80 wt%) and Co-
Cr-Nb (Co:Cr:Nb=79:16
:5wt%) was formed, and the same perfluoropolyether as in Example-1 was arranged to make an 8 mm tape.
Ｃｏ −Ｃｒ膜は２０００人、保磁力９００ （Ｏｓ
）〔比較例−１人とする’） Ｃｏ−Ｃｒ −Ｎｂ 摸
は１８００人、保磁力９０５ （Ｏｓ ）［比較例−１
Ｂとする］である。The Co-Cr film has a magnetic field strength of 2000 and a coercive force of 900 (Os
) [Comparative example-1 person') Co-Cr-Nb sample was 1800 people, coercive force 905 (Os) [Comparative example-1
B].
〔比較例−２〕
厚み１０μｍのポリエチレンナフタレートフィルムで直
径９００Ａのカーボンブラックを３重量％含み、平均粗
さ５ｅ人のフィルムを用い、高周波スパッタリング法で
Ｃｏ−Ｃｒ垂直磁化模を形成した。Ｃｏ −Ｃｒ （Ｃ
ｏ ： ８０ｗｔ％）＠の垂直保磁力は８９０ （６ｅ
）である。Ｃｏ −Ｃｒ膜上に実施例−１と同じパー
フルオロポリエーテルを配し８ミリテーグとした。[Comparative Example-2] A Co--Cr perpendicular magnetization pattern was formed by a high-frequency sputtering method using a polyethylene naphthalate film having a thickness of 10 μm, containing 3% by weight of carbon black having a diameter of 900 A, and having an average roughness of 5e. Co-Cr (C
o: 80wt%) @ has a vertical coercive force of 890 (6e
). The same perfluoropolyether as in Example 1 was placed on the Co--Cr film to form a film of 8 mm.
上記したテープを改造した８ミリビデオによりシリンダ
回転数を変化させ、ギャップ長０．２７１ｍのメタルイ
ンギャップ型の磁気ヘッドで記録波長０．３６μｍを記
録再生し比較した結果を表にまとめて示した。Using an 8mm video tape modified from the above, the cylinder rotational speed was varied, and a metal-in-gap magnetic head with a gap length of 0.271m was used to record and reproduce data at a recording wavelength of 0.36μm.The results were summarized in a table and compared. .
尚スチル時間は、再生出力が３ ｄＢ低下するまでの時
間である。Note that the still time is the time until the reproduction output decreases by 3 dB.
発明の効果
以上のように本発明によれば、高密度記録を広帯域化し
て行う時必要な高速摺接での安定な％確保と耐久性を兼
ね備えた磁気記録媒体が得られるといったすぐれた効果
がある。Effects of the Invention As described above, the present invention has the excellent effect of providing a magnetic recording medium that has both stability and durability in high-speed sliding contact, which is necessary when performing high-density recording over a wide band. be.
図は本発明の実施例の磁気記録媒体の拡大断面図である
。
１・・・・・・高分子フィルム、２・・・・・・カーボ
ンブラック、３・・・・・・垂直磁化膜。
代理人の氏名 弁理士 粟 野 重 孝 ほか１名／−
−−惠′δ子フィｊレム
２−７］−ボンフラッフ
３− 倉ａ磁化囁The figure is an enlarged sectional view of a magnetic recording medium according to an embodiment of the present invention. 1...Polymer film, 2...Carbon black, 3...Perpendicular magnetization film. Name of agent: Patent attorney Shigetaka Awano and 1 other person/-
--Ei'δ子 Filem 2-7]-Bonfluff 3-Kuraa Magnetization Whisper
Claims (1)
ｏ系合金垂直磁化膜を形成したことを特徴とする磁気記
録媒体。C directly onto the polymer film mixed with carbon black.
A magnetic recording medium comprising an o-based alloy perpendicularly magnetized film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29491688A JPH02141920A (en) | 1988-11-22 | 1988-11-22 | Magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29491688A JPH02141920A (en) | 1988-11-22 | 1988-11-22 | Magnetic recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02141920A true JPH02141920A (en) | 1990-05-31 |
Family
ID=17813911
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29491688A Pending JPH02141920A (en) | 1988-11-22 | 1988-11-22 | Magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02141920A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57113418A (en) * | 1981-01-05 | 1982-07-14 | Teijin Ltd | Magnetic recording medium |
| JPS63237207A (en) * | 1987-03-24 | 1988-10-03 | Ube Ind Ltd | Production of perpendicular magnetic recording medium |
| JPS63237208A (en) * | 1987-03-24 | 1988-10-03 | Ube Ind Ltd | Perpendicular magnetic recording medium |
-
1988
- 1988-11-22 JP JP29491688A patent/JPH02141920A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57113418A (en) * | 1981-01-05 | 1982-07-14 | Teijin Ltd | Magnetic recording medium |
| JPS63237207A (en) * | 1987-03-24 | 1988-10-03 | Ube Ind Ltd | Production of perpendicular magnetic recording medium |
| JPS63237208A (en) * | 1987-03-24 | 1988-10-03 | Ube Ind Ltd | Perpendicular magnetic recording medium |
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