JPH0618068B2 - Magnetic recording medium and base film - Google Patents
Magnetic recording medium and base filmInfo
- Publication number
- JPH0618068B2 JPH0618068B2 JP60200470A JP20047085A JPH0618068B2 JP H0618068 B2 JPH0618068 B2 JP H0618068B2 JP 60200470 A JP60200470 A JP 60200470A JP 20047085 A JP20047085 A JP 20047085A JP H0618068 B2 JPH0618068 B2 JP H0618068B2
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- Prior art keywords
- film
- magnetic recording
- recording medium
- base film
- mol
- Prior art date
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Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、磁気記録媒体用ベースフィルムおよび磁気記
録媒体に関するものであり、特にヘッドタッチ、耐久
性、走行性の改善に関するものである。TECHNICAL FIELD The present invention relates to a base film for a magnetic recording medium and a magnetic recording medium, and more particularly to improvement of head touch, durability, and runnability.
［開示の概要］ 本明細書は、磁気記録媒体において、ベースフィルムを
高さ0.1μｍ以下の突起が１mm2当り平均１０5〜１０9個
存在する、特定のポリイミドフィルムとすることによっ
て、走行特性、耐久性、ヘッドタッチに優れた高密度磁
気記録媒体を提供する技術を開示するものである。[Summary of Disclosure] In the present specification, the running characteristics of the magnetic recording medium are determined by using a specific polyimide film in which the base film has an average of 10 5 to 10 9 protrusions with a height of 0.1 μm or less per 1 mm 2. , A technique for providing a high-density magnetic recording medium excellent in durability and head touch is disclosed.
［従来の技術］ 強磁性金属薄膜、強磁性酸化物薄膜あるいは強磁性窒化
物薄膜を磁気記録層として形成した磁気記録媒体は高密
度記録用として優れた特性を有するものである。その例
をあげると、Co膜、Co-Ni膜、Co-Cr膜、Co酸化物膜、Ba
−フェライト膜等があるが、これらの薄膜は、生産性、
特性の制御性等の優れている真空蒸着法、スパッタリン
グ法、イオンプレーティング法で代表される薄膜堆積法
により形成される。[Prior Art] A magnetic recording medium in which a ferromagnetic metal thin film, a ferromagnetic oxide thin film or a ferromagnetic nitride thin film is formed as a magnetic recording layer has excellent characteristics for high density recording. Examples are Co film, Co-Ni film, Co-Cr film, Co oxide film, and Ba film.
-There are ferrite films etc., but these thin films are
It is formed by a thin film deposition method typified by a vacuum deposition method, a sputtering method, and an ion plating method, which have excellent controllability of characteristics.
これら薄膜堆積法を用いた磁気記録媒体の製造プロセス
においては、特性向上のためにベースフィルムが高温に
保持されたり、蒸発源からの輻射熱、入射粒子の衝撃に
より高温にさらされる。磁気テープあるいはフロッピー
ディスクタイプの磁気記録媒体の基体には可撓性の高分
子フィルムが用いられるが、上記理由により、従来専ら
使用されてきたポリエステルフィルムよりも耐熱性に優
れた高分子フィルムが必要である。そのような耐熱性樹
脂の候補として、ポリエーテルエーテルケトン、ポリフ
ェニルサルファイド、ポリエーテルスルホン、ポリアミ
ド、ポリイミドが挙げられるが、中でもポリイミドフィ
ルムが最も耐熱性が高く、Co-Cr垂直磁気記録媒体の様
に薄膜形成時に基体を100℃以上に保持する必要のあ
る、磁気記録媒体用ベースフィルムとして最も適してい
る。In the manufacturing process of a magnetic recording medium using these thin film deposition methods, the base film is kept at a high temperature for the purpose of improving the characteristics, or is exposed to a high temperature by the radiant heat from an evaporation source and the impact of incident particles. A flexible polymer film is used as a base material of a magnetic recording medium of a magnetic tape or a floppy disk type, but for the above reason, a polymer film having higher heat resistance than a polyester film which has been used exclusively in the past is required. Is. Polyether ether ketone, polyphenyl sulfide, polyether sulfone, polyamide, and polyimide are mentioned as candidates for such a heat-resistant resin. Among them, the polyimide film has the highest heat resistance, and is similar to Co-Cr perpendicular magnetic recording media. It is most suitable as a base film for magnetic recording media, which requires the substrate to be kept at 100 ° C or higher during thin film formation.
［発明が解決しようとする問題点］ ところで、前述したような強磁性薄膜型磁気記録媒体で
は、従来の塗布型磁気記録媒体に比べて磁気記録層の厚
さが非常に薄いため、媒体の走行性やドロップアウトの
重要なファクターである磁気記録層の表面粗度は、ベー
スフィルムの表面粗度に依存する。しかしながら従来の
ポリイミドフィルムでは適当な表面粗度のものがなく、
摩擦が大きすぎて走行性の悪化を招いたり、ドロップア
ウト発生を惹き起していた。[Problems to be Solved by the Invention] In the ferromagnetic thin film magnetic recording medium as described above, the magnetic recording layer is very thin as compared with the conventional coating type magnetic recording medium. The surface roughness of the magnetic recording layer, which is an important factor of the property and dropout, depends on the surface roughness of the base film. However, conventional polyimide films do not have suitable surface roughness,
The friction was too great, which deteriorated running performance and caused dropouts.
本発明は上述した従来ポリイミドフィルムの問題点を除
去し、走行特性、耐久性、ヘッドタッチに優れた高密度
磁気記録媒体用ベースフィルムおよび磁気記録媒体を提
供するものである。The present invention eliminates the above-mentioned problems of conventional polyimide films, and provides a base film for a high-density magnetic recording medium and a magnetic recording medium which are excellent in running characteristics, durability, and head touch.
［問題点を解決するための手段および作用］ 本発明は、高さ０．１μｍ以下の突起が１mm2当たり平
均１０5〜１０9個存在するポリイミドフィルムからなる
磁気記録媒体用ベースフィルムであって、該ポリイミド
フィルムが、全芳香族ジアミン成分に対して少なくとも
３０モル％以上のパラフェニレンジアミン（以下ＰＰＤ
と略す）および０〜７０モル％のジアミノジフェニルエ
ーテル（以下ＤＡＤＥと略す）からなる芳香族ジアミン
成分と、ビフェニルテトラカルボン酸二無水物（以下Ｂ
ＰＤＡと略す）およびピロメリット酸二無水物（以下Ｐ
ＭＤＡと略す）とからなるテトラカルボン酸成分とを共
重合して得られた芳香族ポリアミック酸溶液から形成さ
れたことを特徴とするベースフィルム、さらには、前記
フィルム上に薄膜堆積法により強磁性薄膜を形成した磁
気記録媒体である。本発明において、PPD，DADE，BPDA
およびPMDAの３成分あるいは４成分からなるポリイミド
フィルムは熱膨張係数が1.0〜3.0×１０-5であり、この
フィルム上に形成される磁気記録層の熱膨張係数に近
い。そのため磁気記録層形成時の熱応力、あるいは環境
温度の変化にともなう媒体のそりを緩和するように適切
な熱膨張係数のポリイミドフィルムを、前記３成分ある
いは４成分の配合比を変化することにより選択すること
が可能で、カールのない磁気記録媒体を製造できる。[Means and Actions for Solving Problems] The present invention relates to a base film for a magnetic recording medium, which comprises a polyimide film having an average of 10 5 to 10 9 protrusions having a height of 0.1 μm or less per 1 mm 2. The polyimide film contains at least 30 mol% or more of para-phenylenediamine (hereinafter referred to as PPD) with respect to the wholly aromatic diamine component.
And an aromatic diamine component consisting of 0 to 70 mol% of diaminodiphenyl ether (hereinafter abbreviated as DADE), and biphenyltetracarboxylic dianhydride (hereinafter B).
PDA) and pyromellitic dianhydride (hereinafter P
(Abbreviated as MDA)) and a base film formed from an aromatic polyamic acid solution obtained by copolymerization with a tetracarboxylic acid component, and further, a ferromagnetic film formed on the film by a thin film deposition method. A magnetic recording medium having a thin film formed thereon. In the present invention, PPD, DADE, BPDA
The thermal expansion coefficient of the polyimide film consisting of three or four components of PMDA and PMDA is 1.0 to 3.0 × 10 −5, which is close to the thermal expansion coefficient of the magnetic recording layer formed on this film. Therefore, a polyimide film having an appropriate coefficient of thermal expansion is selected by changing the compounding ratio of the above three components or four components so as to alleviate the warpage of the medium due to the thermal stress at the time of forming the magnetic recording layer or the change of the environmental temperature. It is possible to produce a curl-free magnetic recording medium.
表面突起物は流延ベルト上に微細な凹凸を形成し、この
凹凸をフィルム面に転写して形成することも可能である
が、ポリイミド溶液中にAl2O3，TiO2，MgO，Ｃ，SiO2，
BaSO4，Cr2O3，CaCO3，Fe等の無機物微粒子を分散させ
る方が微小な凹凸の制御が可能である。表面突起の高さ
は40〜0.1μｍが望ましく、さらには40〜300であ
ることが好ましい。高さ40以下の突起は摩擦係数減少
の効果が現われない。また突起物は表面１mm2当り１０5
〜１０9個であることが望ましい。１０5未満では突起１
個当りのヘッドとの接触圧力が大きくなるため、突起部
分が削り取られる。また１０9を超える場合において
は、粒子混合量が過大となり粒子が凝集し、粗大な突起
の発生を招く。さらに好ましくは１mm2当り１０6〜１０
8個の突起密度であり、これにより媒体の摩擦係数を減
少させることができる。The surface protrusions can be formed by forming fine irregularities on the casting belt and transferring the irregularities to the film surface. However, Al 2 O 3 , TiO 2 , MgO, C, SiO 2 ,
Finer irregularities can be controlled by dispersing inorganic fine particles such as BaSO 4 , Cr 2 O 3 , CaCO 3 , and Fe. The height of the surface protrusions is preferably 40 to 0.1 μm, more preferably 40 to 300. A protrusion with a height of 40 or less does not show the effect of reducing the friction coefficient. Also, the number of protrusions is 10 5 per 1 mm 2 of surface.
It is desirable that 10 nine. If it is less than 10 5 , protrusion 1
Since the contact pressure with the head per piece becomes large, the protruding portion is scraped off. On the other hand, when it exceeds 10 9 , the mixed amount of particles becomes excessively large, and the particles agglomerate, resulting in the formation of coarse protrusions. More preferably, 10 6 to 10 per 1 mm 2
It has a density of 8 protrusions, which can reduce the friction coefficient of the medium.
上記ポリイミドフィルム上に形成する磁気記録層は、F
e，Co，Niを主成分とする強磁性合金膜、強磁性酸化物
膜あるいは強磁性窒化物膜である。これらの磁気記録層
は真空蒸着法、イオンプレーティング法、スパッタリン
グ法等の物理蒸着法、あるいはメッキ法等で形成され
る。The magnetic recording layer formed on the polyimide film is F
A ferromagnetic alloy film, a ferromagnetic oxide film, or a ferromagnetic nitride film containing e, Co, and Ni as main components. These magnetic recording layers are formed by a physical vapor deposition method such as a vacuum vapor deposition method, an ion plating method, a sputtering method, or a plating method.
中でも真空蒸着あるいはスパッタリング法で形成したCr
15〜23wt％、残部CoからなるCo-Cr垂直磁化膜は従来の
面内磁化媒体に比べ、高密度記録用として非常に優れて
いる。Above all, Cr formed by vacuum deposition or sputtering
The Co-Cr perpendicular magnetization film consisting of 15 to 23 wt% and the balance Co is very excellent for high density recording as compared with the conventional in-plane magnetization medium.
これら磁気記録層の下部は、ベースフィルムとの付着力
の向上、結晶配向性、磁気特性の向上を目的として、A
l，Ge，Cr，Ti，Sio2等の薄膜や、垂直磁化膜の裏打ち
層としてFe-Ni膜、Co-Zr膜等の高透磁率層が設けられる
場合もある。The lower part of these magnetic recording layers is made of A for the purpose of improving adhesion to the base film, crystal orientation, and magnetic properties.
In some cases, a thin film of l, Ge, Cr, Ti, Sio 2 or the like or a high magnetic permeability layer such as a Fe-Ni film or a Co-Zr film is provided as a backing layer of the perpendicular magnetization film.
また、磁気記録層上に、耐蝕性、耐摩耗性、潤滑性を向
上するために、Al2O3，SiO2，Si3N4，Mo，Ni等の無機物
層あるいはフッ素樹脂、脂肪酸エステル、ステアリン酸
等の有機物層が形成される場合もある。前記Co-Cr膜の
場合においては、Co酸化物層が耐久性の向上、摩擦の低
減に有効である。Further, on the magnetic recording layer, in order to improve corrosion resistance, wear resistance and lubricity, an inorganic layer such as Al 2 O 3 , SiO 2 , Si 3 N 4 , Mo and Ni or a fluororesin, a fatty acid ester, In some cases, an organic material layer such as stearic acid may be formed. In the case of the Co-Cr film, the Co oxide layer is effective for improving durability and reducing friction.
［実施例］ 実施例１ PPD 80モル％、DADE 20モル％からなるジアミン成分
と、BPDA 70モル％、PMDA 30モル％からなる酸二無水物
成分、および無機微粒子として平均粒径50μｍのTiO2粒
子を原料として、厚み９μｍのポリイミドフィルムを製
作した。このポリイミドフィルムの熱膨張係数は1.9×1
0-5、引張り弾性定数は624kg／mm2であった。また、タ
リステップ（テーラーホブソン製）で測定した最大粗さ
540、10点平均粗さ210であり、走査型電子顕微鏡
（SEM）による表面写真により突起密度は平均２×107個
／mm2であった。Example 1 A diamine component consisting of 80 mol% PPD and 20 mol% DADE, an acid dianhydride component consisting of 70 mol% BPDA and 30 mol% PMDA, and TiO 2 having an average particle size of 50 μm as inorganic fine particles. A polyimide film having a thickness of 9 μm was produced using the particles as a raw material. The coefficient of thermal expansion of this polyimide film is 1.9 x 1
The tensile elastic constant was 0 -5 and 624 kg / mm 2 . Also, the maximum roughness measured by Taristep (made by Taylor Hobson)
The average roughness was 540 and 10 points 210, and the projection density was 2 × 10 7 pieces / mm 2 on average according to the surface photograph by a scanning electron microscope (SEM).
このポリイミドフィルム上に電子ビーム加熱連続蒸着装
置にて、Co 79wt％、Cr 21wt％のCo-Cr膜を0.4μｍ形成
した。さらにCo-Cr膜上に反応スパッタリング法によ
り、Co酸化物膜を60形成し、磁気テープを製造した。A Co-Cr film containing 79 wt% of Co and 21 wt% of Cr was formed to 0.4 μm on the polyimide film by an electron beam heating continuous vapor deposition apparatus. Further, 60 Co oxide films were formed on the Co—Cr film by a reactive sputtering method to manufacture a magnetic tape.
比較例１ 実施例１と同一組成のジアミン成分および酸二無水物成
分から９μｍポリイミドフィルムを製作した。ただしこ
のフィルムにはTiO2の微粒子が含まれていない。このポ
リイミドフィルムの表面粗さは、最大粗さ470、10点
平均粗さ70であり、SEM観察による表面突起数は平均1
03個／mm2である。Comparative Example 1 A 9 μm polyimide film was prepared from a diamine component and an acid dianhydride component having the same composition as in Example 1. However, this film does not contain fine particles of TiO 2 . The surface roughness of this polyimide film is maximum roughness 470, 10-point average roughness 70, and the number of surface protrusions by SEM observation is 1 on average.
It is 0 3 pieces / mm 2 .
このポリイミドフィルムに実施例１と同一方法でCo-Cr
膜およびCo酸化膜を形成し、磁気テープで製造した。This polyimide film was coated with Co-Cr in the same manner as in Example 1.
A film and a Co oxide film were formed and manufactured with a magnetic tape.
実施例１および比較例１の磁気テープの４mmφステンレ
ス棒（仕上げ精度0.2s）に対する摩擦係数はそれぞれ0.
29および0.42であった。すなわち実施例１の本発明磁気
テープはデッキにおいても走行がスムーズであるのに対
し、比較例１の磁気テープはテープ鳴きを生じ、走行が
不安定であった。The friction coefficient of the magnetic tapes of Example 1 and Comparative Example 1 with respect to a 4 mmφ stainless steel rod (finishing accuracy: 0.2 s) was 0.
29 and 0.42. That is, the magnetic tape of the present invention of Example 1 runs smoothly even on the deck, whereas the magnetic tape of Comparative Example 1 causes tape squeaking and the running is unstable.
実施例２ PPD 50モル％およびDADE 50モル％からなるジアミン成
分と、BPDA 40モル％およびPMDA 60モル％からなるテト
ラカルボン酸成分、および無機微粒子として平均粒径30
μｍのSiO2およびＣを混合し重合流延して40μｍ厚のポ
リイミドフィルムを得た。このポリイミドフィルムの熱
膨張係数は2.6×10-5、引張り弾性率は396kg／mm2であ
った。このポリイミドフィルムの表面粗さは実施例１と
同一方法で測定し、最大粗さ410、10点平均粗さ150
であった。また突起密度は平均3.5×107個／mm2であっ
た。Example 2 Diamine component consisting of 50 mol% PPD and 50 mol% DADE, tetracarboxylic acid component consisting of 40 mol% BPDA and 60 mol% PMDA, and an average particle size of 30 as inorganic fine particles.
A 40 μm-thick polyimide film was obtained by mixing and mixing the SiO 2 and C of μm and casting by polymerization. The coefficient of thermal expansion of this polyimide film was 2.6 × 10 −5 , and the tensile modulus was 396 kg / mm 2 . The surface roughness of this polyimide film was measured by the same method as in Example 1, and the maximum roughness was 410 and the 10-point average roughness was 150.
Met. The protrusion density was 3.5 × 10 7 protrusions / mm 2 on average.
このポリイミドフィルムを150℃に加熱した上に、Co 80
wt％−Cr 20wt％の合金ターゲットを使用し成膜速度0.2
μｍ／minでスパッタリングし、Co-Cr膜を0.5μｍ形成
した。さらにCo-Cr膜上に反応スパッタ法によりCo酸化
膜を80形成し、垂直磁気記録フロッピーディスクを製
作した。After heating this polyimide film to 150 ° C, Co 80
wt% -Cr 20wt% alloy target is used and film formation rate is 0.2
Sputtering was performed at μm / min to form a Co—Cr film of 0.5 μm. Furthermore, a Co oxide film was formed on the Co-Cr film by a reactive sputtering method to fabricate a perpendicular magnetic recording floppy disk.
比較例２ 実施例２と同一成分でSiO2およびＣ微粒子を含まないポ
リイミドフィルム上に実施例２と同一方法、同一条件で
Co-Cr膜を0.5μｍ、Co-O膜を80形成し、垂直磁気記録
フロッピーディスクを製作した。このポリイミドフィル
ムの表面粗さは最大粗さ270、10点平均粗さ30であ
り、突起密度は平均２×102個／mm2であった。Comparative Example 2 The same method and the same conditions as in Example 2 were applied on a polyimide film containing the same components as in Example 2 but containing neither SiO 2 nor C particles.
A perpendicular magnetic recording floppy disk was manufactured by forming a Co-Cr film of 0.5 μm and a Co-O film of 80. The surface roughness of this polyimide film was a maximum roughness of 270 and a 10-point average roughness of 30, and the protrusion density was an average of 2 × 10 2 pieces / mm 2 .
上記実施例２および比較例２のフロッピーディスクをリ
ング型ヘッドで再生出力の耐久試験を行なった。100万
パス後、比較例２のフロッピーディスクの測定に使用し
たヘッドにはディスクとヘッドとの摩擦で生じた摩耗粉
が付着していたのに対し、実施例２の本発明ディスクの
測定に使用したヘッドに付着していた摩耗粉は微量であ
り、ヘッド、媒体の長寿命化に有効である。The floppy disks of Example 2 and Comparative Example 2 were subjected to a reproduction output endurance test with a ring head. After 1 million passes, the head used in the measurement of the floppy disk of Comparative Example 2 had abrasion powder generated due to the friction between the disk and the head, whereas it was used in the measurement of the disk of the present invention in Example 2. The amount of abrasion powder attached to the formed head is very small, which is effective for extending the life of the head and the medium.
［発明の効果］ 以上、実施例により説明した様に本発明のベースフィル
ム上に強磁性薄膜を形成した本発明磁気記録媒体は、テ
ープの走行およびヘッドタッチの重要なファクターであ
る摩擦係数は小さく、走行性、耐久性に優れた磁気記録
媒体を提供するものである。[Effects of the Invention] As described above, the magnetic recording medium of the present invention in which a ferromagnetic thin film is formed on the base film of the present invention has a small coefficient of friction, which is an important factor for tape running and head touch. The present invention provides a magnetic recording medium excellent in running property and durability.
Claims (3)
平均１０5〜１０9個存在するポリイミドフィルムからな
る磁気記録媒体用ベースフィルムであって、該ポリイミ
ドフィルムが、全芳香族ジアミン成分に対して少なくと
も３０モル％以上のパラフェニレンジアミンおよび０〜
７０モル％のジアミノジフェニルエーテルからなる芳香
族ジアミン成分と、ビフェニルテトラカルボン酸二無水
物およびピロメリット酸二無水物とからなるテトラカル
ボン酸成分とを共重合して得られた芳香族ポリアミック
酸溶液から形成されたことを特徴とするベースフィル
ム。1. A base film for a magnetic recording medium comprising a polyimide film having an average of 10 5 to 10 9 protrusions having a height of 0.1 μm or less per 1 mm 2 , wherein the polyimide film is a wholly aromatic diamine component. To at least 30 mol% or more of para-phenylenediamine and 0 to
From an aromatic polyamic acid solution obtained by copolymerizing an aromatic diamine component consisting of 70 mol% of diaminodiphenyl ether and a tetracarboxylic acid component consisting of biphenyltetracarboxylic dianhydride and pyromellitic dianhydride A base film characterized by being formed.
平均１０5〜１０9個存在するベースフィルム上に薄膜堆
積法により強磁性薄膜を形成した磁気記録媒体であっ
て、該ベースフィルムが、全芳香族ジアミン成分に対し
て少なくとも３０モル％以上のパラフェニレンジアミン
および０〜７０モル％のジアミノジフェニルエーテルか
らなる芳香族ジアミン成分と、ビフェニルテトラカルボ
ン酸二無水物およびピロメリット酸二無水物とからなる
テトラカルボン酸成分とを共重合して得られた芳香族ポ
リアミック酸溶液から形成されたポリイミドからなるこ
とを特徴とする磁気記録媒体。2. A magnetic recording medium in which a ferromagnetic thin film is formed by a thin film deposition method on a base film having an average of 10 5 to 10 9 protrusions having a height of 0.1 μm or less per 1 mm 2 , which is a base film. Is an aromatic diamine component consisting of at least 30 mol% or more of paraphenylenediamine and 0 to 70 mol% of diaminodiphenyl ether, and biphenyltetracarboxylic dianhydride and pyromellitic dianhydride, based on the total aromatic diamine component. A magnetic recording medium comprising a polyimide formed from an aromatic polyamic acid solution obtained by copolymerizing a tetracarboxylic acid component consisting of
金膜であり、前記Co−Cr合金膜上にCo酸化物層を有する
ことを特徴とする特許請求の範囲第２項に記載の磁気記
録媒体。3. The magnetic recording layer according to claim 2, wherein at least one layer is a Co—Cr layer alloy film, and a Co oxide layer is provided on the Co—Cr alloy film. Magnetic recording medium.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60200470A JPH0618068B2 (en) | 1985-09-12 | 1985-09-12 | Magnetic recording medium and base film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60200470A JPH0618068B2 (en) | 1985-09-12 | 1985-09-12 | Magnetic recording medium and base film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6262423A JPS6262423A (en) | 1987-03-19 |
| JPH0618068B2 true JPH0618068B2 (en) | 1994-03-09 |
Family
ID=16424850
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60200470A Expired - Lifetime JPH0618068B2 (en) | 1985-09-12 | 1985-09-12 | Magnetic recording medium and base film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0618068B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0762082B2 (en) * | 1988-07-29 | 1995-07-05 | 宇部興産株式会社 | Polyimide film for recording medium and manufacturing method thereof |
| WO2009142938A1 (en) * | 2008-05-20 | 2009-11-26 | E. I. Du Pont De Nemours And Company | Thermally and dimensionally stable polyimide films and methods relating thereto |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60127523A (en) * | 1983-12-14 | 1985-07-08 | Toray Ind Inc | Base film for magnetic recording medium in high density |
-
1985
- 1985-09-12 JP JP60200470A patent/JPH0618068B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6262423A (en) | 1987-03-19 |
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