JP2647123B2 - Magnetic recording media - Google Patents
Magnetic recording mediaInfo
- Publication number
- JP2647123B2 JP2647123B2 JP7575388A JP7575388A JP2647123B2 JP 2647123 B2 JP2647123 B2 JP 2647123B2 JP 7575388 A JP7575388 A JP 7575388A JP 7575388 A JP7575388 A JP 7575388A JP 2647123 B2 JP2647123 B2 JP 2647123B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- powder
- weight
- magnetic recording
- magnetic layer
- 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.)
- Expired - Lifetime
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- Magnetic Record Carriers (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、磁気テープ、磁気ディスク及び磁気ドラム
等の磁気記録媒体、特に、繰返し走行性（耐久性）及び
電磁変換特性の向上した磁気記録媒体に関する。Description: BACKGROUND OF THE INVENTION The present invention relates to a magnetic recording medium such as a magnetic tape, a magnetic disk, and a magnetic drum, and more particularly, to a magnetic recording with improved repetitive running (durability) and electromagnetic conversion characteristics. Regarding the medium.
〔従来の技術〕 磁気記録媒体が具備すべき重要なファクターである電
磁変換特性及び繰返し走行性（耐久性）を向上させるた
めには、磁性粉末の分散性を向上させる他に、その充填
性（パッキング）を向上させること及び磁性層の強度を
向上させることも重要である。[Prior Art] In order to improve electromagnetic conversion characteristics and repetitive running properties (durability), which are important factors that a magnetic recording medium should have, besides improving the dispersibility of a magnetic powder, its filling property ( It is also important to improve the packing) and the strength of the magnetic layer.
磁性粉末の充填性を向上させるには、磁性層における
磁性粉末の配向性（各粉末の向きが同方向になる）を向
上させることが必要であり、配向性が悪いと磁性粉末の
充填性が不十分となり、その結果出力の低下が起こる
等、電磁変換特性が損なわれる。磁性粉末を配向させる
手段としては、従来より磁性粉末を含む磁性層を磁場配
向処理する方法が採られており、その際磁性粉末の分散
性を良くして磁性粉末が配向し易いようにしている。そ
して、そのための分散剤の開発が種々行われている。In order to improve the filling property of the magnetic powder, it is necessary to improve the orientation of the magnetic powder in the magnetic layer (the orientation of each powder is in the same direction). Electromagnetic conversion characteristics are impaired, such as insufficient output, resulting in a decrease in output. As a means for orienting the magnetic powder, a method of magnetically orienting a magnetic layer containing the magnetic powder has conventionally been adopted. At this time, the dispersibility of the magnetic powder is improved so that the magnetic powder is easily oriented. . And various development of the dispersing agent for that is performed.
また、磁性層の強度が不十分であると、磁気記録媒体
を繰返し使用した際に、磁性層の一部が剥がれて磁気ヘ
ッドに付着し、ヘッドを汚したり、ヘッドの目詰まり等
を原因とする出力の低下や摩擦係数の上昇等が起こり、
磁気記録媒体の耐久性が損なわれ、その結果電磁変換特
性も悪化する。そこで、これらの対策として、従来より
次のような方法が採られている。バインダーを硬化剤
で架橋強化する。アルミナや酸化クロム等の無機顔料
を磁性層に添加する。磁性層に添加する潤滑剤の種類
及び量を調整する。In addition, if the strength of the magnetic layer is insufficient, when the magnetic recording medium is used repeatedly, a part of the magnetic layer is peeled off and adheres to the magnetic head, causing the head to become dirty or clogged. The output decreases, the friction coefficient increases, etc.
The durability of the magnetic recording medium is impaired, and as a result, the electromagnetic conversion characteristics are also deteriorated. Therefore, the following methods have conventionally been adopted as these countermeasures. The binder is strengthened by crosslinking with a curing agent. An inorganic pigment such as alumina or chromium oxide is added to the magnetic layer. The type and amount of the lubricant added to the magnetic layer are adjusted.
しかしながら、磁性粉末の配向性の向上は、従来の分
散剤による場合充分とは言い難く、更に配向性を向上さ
せることが課題とされている。However, the improvement of the orientation of the magnetic powder cannot be said to be sufficient when the conventional dispersant is used, and it is an issue to further improve the orientation.
また、磁性層の強化に関しては、前記及びの方法
では、充分な効果が得られず、また、前記の方法で
は、無機顔料の添加によって、磁性層の強度は向上する
ものの、磁性粉末の分散性が損なわれたり、それに付随
して充填性（配向性）が損なわれることがあり、また、
前記の方法による場合では、潤滑剤の調整に労力を要
し、しかも効果も不充分である。Further, regarding the strengthening of the magnetic layer, the above-mentioned method and the above-mentioned method do not provide a sufficient effect, and in the above-mentioned method, although the strength of the magnetic layer is improved by adding an inorganic pigment, the dispersibility of the magnetic powder is improved. May be impaired, and concomitantly the filling property (orientation) may be impaired.
In the case of the above-mentioned method, labor is required for adjusting the lubricant, and the effect is insufficient.
従って、本発明の目的は、上述の従来の改良法とは基
本的に異なる手段により、繰返し走行性（耐久性）及び
電磁変換特性の向上した磁気記録媒体を提供することに
ある。SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a magnetic recording medium having improved repetitive running properties (durability) and improved electromagnetic conversion characteristics by means basically different from the above-mentioned conventional improvement method.
本発明者らは、鋭意研究した結果、磁性層中に特定形
状のγ−Al2O3粉末及び特定の非磁性粉末を含有させ、
且つ強磁性粉末として特定の強磁性合金粉末を用いるこ
とにより、磁性層の耐久性及び磁性粉末の充填性（配向
性）が向上し、その結果前記目的が達成されることを知
見した。The present inventors have made intensive studies and as a result, the magnetic layer contains a specific shape of γ-Al 2 O 3 powder and a specific non-magnetic powder,
In addition, it has been found that by using a specific ferromagnetic alloy powder as the ferromagnetic powder, the durability of the magnetic layer and the filling property (orientation) of the magnetic powder are improved, and as a result, the object is achieved.
本発明は、上記知見に基づきなされたもので、非磁性
支持体上に強磁性粉末及びバインダーを含む磁性層を塗
設してなる磁気記録媒体において、上記磁性層中に、軸
比（長軸長／短軸長）が３〜50の針状γ−Al2O3粉末、
及び軸比（長軸長／短軸長）が2.5以下でモース硬度が
３以上の非磁性粉末を含有させ、また上記強磁性粉末と
して、鉄の含有率が60重量％以上で比表面積が40m2/g以
上の強磁性合金粉末を用いることを特徴とする磁気記録
媒体を提供するものである。The present invention has been made based on the above findings. In a magnetic recording medium in which a magnetic layer containing a ferromagnetic powder and a binder is coated on a nonmagnetic support, an axial ratio (long axis) is contained in the magnetic layer. Needle-like γ-Al 2 O 3 powder having a length of 3 to 50
And a non-magnetic powder having an axis ratio (long axis length / short axis length) of 2.5 or less and a Mohs hardness of 3 or more. As the ferromagnetic powder, an iron content of 60% by weight or more and a specific surface area of 40 m. It is intended to provide a magnetic recording medium characterized by using a ferromagnetic alloy powder of 2 / g or more.
以下、本発明の磁気記録媒体について詳述する。 Hereinafter, the magnetic recording medium of the present invention will be described in detail.
本発明の磁気記録媒体に用いられる針状γ−Al2O3粉
末は、軸比（長軸長／短軸長）が３〜50、好ましくは５
〜40の形状のものである。軸比が３未満であると、耐久
性及び磁性粉末の充填性が不十分となる。また軸比が50
超であると、電磁変換特性が不十分となる。The acicular γ-Al 2 O 3 powder used in the magnetic recording medium of the present invention has an axial ratio (major axis length / minor axis length) of 3 to 50, preferably 5 to 5.
~ 40 shapes. When the axial ratio is less than 3, the durability and the filling property of the magnetic powder become insufficient. The axis ratio is 50
If it is more than 1, the electromagnetic conversion characteristics become insufficient.
上記γ−Al2O3粉末の長軸長は、通常0.02〜３μｍ、
好ましくは0.05〜２μｍである。The major axis length of the γ-Al 2 O 3 powder is usually 0.02 to 3 μm,
Preferably it is 0.05-2 μm.
また、上記γ−Al2O3粉末の使用量は、強磁性合金粉
末100重量部に対し、好ましくは0.02〜20重量部、更に
好ましくは0.5〜12重量部である。使用量が0.2重量部未
満であると、耐久性が不十分となる傾向がある。また20
重量部超であると、電磁変換特性が不十分となる傾向が
ある。The amount of the γ-Al 2 O 3 powder to be used is preferably 0.02 to 20 parts by weight, more preferably 0.5 to 12 parts by weight, based on 100 parts by weight of the ferromagnetic alloy powder. If the amount is less than 0.2 parts by weight, the durability tends to be insufficient. Also 20
When the amount is more than part by weight, the electromagnetic conversion characteristics tend to be insufficient.
また、本発明の磁気記録媒体において上記γ−Al2O3
粉末と併用される非磁性粉末は、軸比（長軸長／短軸
長）が2.5以下でモース硬度が３以上の粒状粉末であ
り、かかる非磁性粉末としては、例えば、α−Fe2O3、
ゲーサイト、α−Al2O3、Cr2O3、SiC等、通常研磨剤と
して使用されている無機粉末、及びTiO2、CaCO3、ZnO等
の、走行安定性のために使用される無機粉末を用いるこ
とができる。上記非磁性粉末の軸比が2.5超であると、
磁性粉末の充填性が不十分となる。また、モース硬度が
３未満であると、耐久性が不十分となる。Further, in the magnetic recording medium of the present invention, the above γ-Al 2 O 3
The non-magnetic powder used in combination with the powder is a granular powder having an axial ratio (major axis length / minor axis length) of 2.5 or less and a Mohs hardness of 3 or more. Examples of such non-magnetic powder include α-Fe 2 O 3 ,
Goethite, α-Al 2 O 3 , Cr 2 O 3 , SiC etc., inorganic powders usually used as abrasives, and TiO 2 , CaCO 3 , ZnO etc., inorganics used for running stability Powder can be used. When the axial ratio of the nonmagnetic powder is more than 2.5,
The filling properties of the magnetic powder become insufficient. When the Mohs hardness is less than 3, the durability becomes insufficient.
上記非磁性粉末の長軸長は、通常0.02〜３μｍ、好ま
しくは0.1〜１μｍである。The major axis length of the nonmagnetic powder is usually 0.02 to 3 μm, preferably 0.1 to 1 μm.
上記非磁性粉末の使用量は、強磁性合金粉末100重量
部に対し、好ましくは0.2〜20重量部、更に好ましくは
0.5〜12重量部である。使用量が0.2重量部未満である
と、耐久性が不十分となる傾向がある。また20重量部超
であると、磁性粉末の充填性が不十分となる傾向があ
る。The amount of the nonmagnetic powder used is preferably 0.2 to 20 parts by weight, more preferably 100 parts by weight of the ferromagnetic alloy powder.
0.5 to 12 parts by weight. If the amount is less than 0.2 parts by weight, the durability tends to be insufficient. If it exceeds 20 parts by weight, the filling properties of the magnetic powder tend to be insufficient.
また、本発明の磁気記録媒体に用いられる強磁性粉末
は、鉄の含有率が60重量％以上、好ましくは80重量％で
比表面積が40m2/g以上のもので、かかる強磁性粉末とし
ては、例えばFe−Ni、Fe−Co等の強磁性合金粉末、及び
これらの強磁性合金粉末の表面をSiO2、Al2O3、TiO2、Z
rO2で表面処理したものを用いることができる。上記強
磁性合金粉末の鉄の含有量が60重量％未満であったり、
また比表面積が40m2/g未満であると、電磁変換特性が不
十分となる。The ferromagnetic powder used in the magnetic recording medium of the present invention has an iron content of 60% by weight or more, preferably 80% by weight and a specific surface area of 40 m 2 / g or more. For example, ferromagnetic alloy powders such as Fe-Ni and Fe-Co, and the surfaces of these ferromagnetic alloy powders are made of SiO 2 , Al 2 O 3 , TiO 2 , Z
Those surface-treated with rO 2 can be used. The iron content of the ferromagnetic alloy powder is less than 60% by weight,
When the specific surface area is less than 40 m 2 / g, the electromagnetic conversion characteristics become insufficient.
上記強磁性合金粉末の大きさは、通常、長軸長が0.1
〜0.3μｍ程度で、軸比（長軸長／短軸長）が５〜20程
度である。The size of the ferromagnetic alloy powder is generally such that the major axis length is 0.1.
軸 0.3 μm and the axial ratio (major axis length / minor axis length) is about 5-20.
また、本発明の磁気記録媒体に用いられるバインダー
としては、例えば、ポリウレタン、ポリエステル、ポリ
塩化ビニル、塩化ビニル／酢酸ビニル共重合体、塩化ビ
ニル／酢酸ビニル／ポリビニルアルコール共重合体、塩
化ビニル／アクリル酸エステル共重合体、塩化ビニル／
メタクリル酸エステル共重合体、ポリアクリルニトリ
ル、ニトリルゴム、エポキシ樹脂、アルキッド樹脂、ポ
リアミド、ポリアクリル酸エステル、ポリメタクリル酸
エステル、ポリ酢酸ビニル、ポリビニルブチラール、塩
化ビニリデン、硝化綿、マレイン酸変性塩化ビニル／酢
酸ビニル共重合体、エチルセルロース等が挙げられ、こ
れらの樹脂を単独又は２種以上混合して用いられる。Examples of the binder used in the magnetic recording medium of the present invention include polyurethane, polyester, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, vinyl chloride / vinyl acetate / polyvinyl alcohol copolymer, and vinyl chloride / acrylic. Acid ester copolymer, vinyl chloride /
Methacrylate copolymer, polyacrylonitrile, nitrile rubber, epoxy resin, alkyd resin, polyamide, polyacrylate, polymethacrylate, polyvinyl acetate, polyvinyl butyral, vinylidene chloride, nitrified cotton, maleic acid-modified vinyl chloride / Vinyl acetate copolymer, ethyl cellulose and the like, and these resins are used alone or in combination of two or more.
上記バインダーの使用量は、前記強磁性合金粉末100
重量部に対し８〜50重量部が好ましい。The amount of the binder used is the ferromagnetic alloy powder 100.
It is preferably 8 to 50 parts by weight based on parts by weight.
本発明の磁気記録媒体な磁性層には、前記強磁性合金
粉末、前記γ−Al2O3粉末、前記非磁性粉末及び前記バ
インダーの他に、この種の磁性層に通常含有される添加
剤、例えば潤滑剤、研磨剤、帯電防止剤、可塑剤、硬化
剤、分散剤、表面処理剤等を添加することができる。In the magnetic layer of the magnetic recording medium of the present invention, in addition to the ferromagnetic alloy powder, the γ-Al 2 O 3 powder, the non-magnetic powder and the binder, additives usually contained in this type of magnetic layer For example, a lubricant, an abrasive, an antistatic agent, a plasticizer, a curing agent, a dispersant, a surface treatment agent, and the like can be added.
また、本発明の磁気記録媒体に用いられる非磁性支持
体としては、例えば、ポリエチレンテレフタレート（PE
T）のようなポリエステル；ポリエチレン、ポリプロピ
レン等のポリオレフィン；セルローストリアセテート、
セルロースジアセテート等のセルロース誘導体；ポリカ
ーボネート；ポリ塩化ビニル；ポリイミド；芳香族ポリ
アミド等のプラスチックや、Au,Cu等の金属；紙等が挙
げられ、これらの支持体の表面をコロナ放電、放射線、
紫外線等で処理したもの或いは適当な樹脂でプレコート
したものを用いることもできる。この非磁性支持体の形
態は、フィルム、テープ、シート、ディスク、カード、
ドラム等、何れの形態でも良い。As the non-magnetic support used in the magnetic recording medium of the present invention, for example, polyethylene terephthalate (PE)
Polyesters such as T); polyolefins such as polyethylene and polypropylene; cellulose triacetate;
Cellulose derivatives such as cellulose diacetate; polycarbonate; polyvinyl chloride; polyimide; plastics such as aromatic polyamide; metals such as Au and Cu; paper; and the like.
Those treated with ultraviolet rays or the like or those precoated with an appropriate resin can also be used. The form of this non-magnetic support is film, tape, sheet, disk, card,
Any form such as a drum may be used.
本発明の磁気記録媒体は、例えば次のようにして製造
することができる。The magnetic recording medium of the present invention can be manufactured, for example, as follows.
先ず、前記強磁性合金粉末、前記γ−Al2O3粉末、前
記非磁性粉末及び前記バインダーを前記の割合で配合
し、更に必要に応じ各種の前記添加剤を加えた配合物を
常法により溶剤と混合して磁性塗料を調製する。次い
で、この塗料を前記非磁性支持体上に常法により乾燥膜
厚が約0.8〜10μｍになるように塗布し、塗膜を磁場配
向処理後乾燥して、前記非磁性支持体上に磁性層を形成
する。然る後、磁性層をカレンダー処理等の表面処理を
し、更に常法により非磁性支持体の裏面にバックコート
層を形成して本発明の磁気記録媒体を得る。First, the ferromagnetic alloy powder, the γ-Al 2 O 3 powder, the non-magnetic powder and the binder are blended in the ratio described above, and further, if necessary, a blend containing various additives is prepared by a conventional method. A magnetic paint is prepared by mixing with a solvent. Next, this coating material is applied on the non-magnetic support by a conventional method so that a dry film thickness is about 0.8 to 10 μm, and the coating film is subjected to a magnetic field orientation treatment and dried, and a magnetic layer is formed on the non-magnetic support. To form Thereafter, the magnetic layer is subjected to a surface treatment such as a calendering treatment, and a back coat layer is formed on the back surface of the non-magnetic support by a conventional method to obtain the magnetic recording medium of the present invention.
以下に本発明の実施例、比較例及び本発明の効果を示
す試験例を挙げ、本発明を更に詳細に説明する。Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples, and Test Examples showing the effects of the present invention.
実施例１〜９及び比較例1,2 〔磁性層の形成〕 下記塗料配合の配合物を五十嵐機械（株）製のバッチ
式サンドミルで６時間混合後、混合物にコロネートＬ
（商品名、日本ポリウレタン工業（株）製のトリメチロ
ールプロパントリイソシアナート）2.5重量部を添加
し、更に15分間混合を行った後、濾過してガラスビーズ
を分離し、磁性塗料を調製した。この塗料を、10μｍ厚
のPETフィルム上に乾燥膜厚が３μｍになるように塗布
し、塗膜を磁場配向処理後乾燥して、PETフィルム上に
磁性層を形成した。次いで、磁性層の形成されたPETフ
ィルムをロールに巻き取った後、磁性層をカレンダー処
理した。Examples 1 to 9 and Comparative Examples 1 and 2 [Formation of Magnetic Layer] After mixing the following composition with a batch type sand mill manufactured by Igarashi Kikai Co., Ltd. for 6 hours, the mixture was mixed with Coronate L.
2.5 parts by weight of trimethylolpropane triisocyanate (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added, and the mixture was further mixed for 15 minutes, and then filtered to separate glass beads to prepare a magnetic paint. This coating material was applied on a PET film having a thickness of 10 μm so as to have a dry film thickness of 3 μm, and the coating film was subjected to a magnetic field orientation treatment and dried to form a magnetic layer on the PET film. Next, after winding the PET film on which the magnetic layer was formed, the magnetic layer was calendered.
・塗料配合 強磁性合金粉末（第１表参照） 100重量部 レシチン ２重量部 カーボンブラック＊１ ３ 〃 γ−Al2O3（第１表参照） 非磁性粉末＊２（第１表参照） VAGH＊３ 15 〃 ニッポラン2304＊４ 10 〃 ブチルステアレート ２ 〃 メチルエチルケトン 150 〃 トルエン 50 〃 シクロヘキサノン 75 〃 （註）＊1:平均粒子径25nm ＊2:モース硬度５以上 ＊3:ユニオンカーバイド社製の塩化ビニル／酢酸ビニル
／ポリビニルアルコール共重合体 ＊4:日本ポリウレタン工業（株）製のポリウレタン樹脂 〔バックコート層の形成〕 下記バックコート塗料配合の配合物をボールミルで96
時間混合後、混合物にコロネートL20重量部を添加し、
さらに30分間混合を行い、バックコート塗料を調製し
た。この塗料を、前記の磁性層の形成されたPETフィル
ムの裏面に乾燥膜厚が0.5μｍになるように塗布し、塗
膜を乾燥して、バックコート層を形成した。・ Coating compound Ferromagnetic alloy powder (See Table 1) 100 parts by weight Lecithin 2 parts by weight Carbon black * 13 〃 γ-Al 2 O 3 (See Table 1) Non-magnetic powder * 2 (See Table 1) VAGH * 3 15 〃Nipporan 2304 * 4 10 ブ チ ル Butyl stearate 2 メ チ ル Methyl ethyl ketone 150 ト ル エ ン Toluene 50 〃Cyclohexanone 75 〃 (Note) * 1: Average particle diameter 25 nm * 2: Mohs hardness of 5 or more * 3: Chloride manufactured by Union Carbide Vinyl / vinyl acetate / polyvinyl alcohol copolymer * 4: Polyurethane resin manufactured by Nippon Polyurethane Industry Co., Ltd. [Formation of backcoat layer] The following backcoat paint formulation was mixed with a ball mill 96
After mixing for time, add 20 parts by weight of Coronate L to the mixture,
Mixing was further performed for 30 minutes to prepare a back coat paint. This paint was applied to the back surface of the PET film on which the magnetic layer was formed so that the dry film thickness was 0.5 μm, and the paint film was dried to form a back coat layer.
然る後、磁性層及びバックコートの形成されたPETフ
ィルムを8mm幅にスリットし、カセットに装填して、８
ミリビデオカセットを作製した。Thereafter, the PET film on which the magnetic layer and the back coat are formed is slit into an 8 mm width, and is loaded into a cassette.
Millivideo cassettes were made.
・バックコート塗料配合 カーボンブラック＊１ 100重量部 ニトロセルロース 50 〃 ニッポラン2304 50 〃 レシチン ２ 〃 メチルエチルケトン 400 〃 トルエン 200 〃 （註）＊1:平均粒子径25nm （試験例） 上記の実施例及び比較例で作製した８ミリビデオカセ
ットそれぞれについて、下記の繰返し走行テストを行
い、また電磁変換特性を観るために飽和磁束密度及び角
型比を下記の如く求めた。それらの結果を下記第１表に
示す。・ Backcoat paint compounded carbon black * 1 100 parts by weight Nitrocellulose 50 〃 Nipporan 2304 50 〃 Lecithin 2 メ チ ル Methyl ethyl ketone 400 ト ル エ ン Toluene 200 〃 (Note) * 1: Average particle diameter 25 nm (Test example) The above examples and comparative examples For each of the 8 mm video cassettes manufactured in the above, the following repeated running test was performed, and the saturation magnetic flux density and the squareness ratio were obtained as follows in order to observe the electromagnetic conversion characteristics. The results are shown in Table 1 below.
８ミリビデオカセットを８ミリビデオデッキにて100
回繰返し走行テストを行い、走行テスト前後の８ミリビ
デオカセットについて次の特性を測定した。8 mm video cassette is 100 in 8 mm VCR
A running test was performed repeatedly, and the following characteristics of the 8-mm video cassette before and after the running test were measured.
C/N （株）シバソク製の電磁変換測定システムにより、5M
HZで記録した際のノイズスペクトラムを観測し、これよ
りC/Nを求めた。比較例１を基準としその差をdBで表示
した。C / N 5M by electromagnetic conversion measurement system manufactured by Shibasoku Co., Ltd.
Observing the noise spectrum at the time of recording with H Z, it was calculated from the C / N this. With reference to Comparative Example 1, the difference was expressed in dB.
摩擦係数（μ） （株）横浜システム研究所製のテープ試験機TBT−300
Dを用いて、テープを、5mm径シリンダーに磁性面が180
゜接触する状態でテープ速度1.43cm/秒にて走行させ、
巻出側及び巻取側のテンションを測定し、次式より摩擦
係数（μ）を求めた。Coefficient of friction (μ) Tape tester TBT-300 manufactured by Yokohama System Laboratory Co., Ltd.
Using D, place the tape on a 5 mm diameter cylinder with 180
さ せ Run at a tape speed of 1.43 cm / sec in contact with
The tension on the unwinding side and the winding side was measured, and the friction coefficient (μ) was determined from the following equation.
〔飽和磁束密度及び角型比〕 理研電子（株）製の振動試料型磁力計により印加磁場
（kOe）にて飽和磁化し、飽和磁場にて残留磁場値を求
め、次式より飽和磁束密度Bs（Gauss）及び角型比を求
めた。 [Saturation magnetic flux density and squareness ratio] Using a vibrating sample magnetometer manufactured by Riken Denshi Co., Ltd., perform saturation magnetization with an applied magnetic field (kOe), obtain the residual magnetic field value with the saturation magnetic field, and obtain the saturation magnetic flux density Bs from the following equation (Gauss) and squareness ratio were determined.
第１表に示す結果から、実施例のものは、比較例のも
のに比して、繰返し走行性（耐久性）及び電磁変換特性
が向上していることが判る。 From the results shown in Table 1, it can be seen that the example of the present invention has improved repeatability (durability) and electromagnetic conversion characteristics as compared with the comparative example.
〔発明の効果〕 本発明の磁気記録媒体は、繰返し走行性（耐久性）及
び電磁変換特性の向上したものである。 [Effects of the Invention] The magnetic recording medium of the present invention has improved running characteristics (durability) and electromagnetic conversion characteristics.
Claims (1)
ーを含む磁性層を塗設してなる磁気記録媒体において、
上記磁性層中に、軸比（長軸長／短軸長）が３〜50の針
状γ−Al2O3粉末、及び軸比（長軸長／短軸長）が2.5以
下でモース硬度が３以上の非磁性粉末を含有させ、また
上記強磁性粉末として、鉄の含有率が60重量％以上で比
表面積が40m2/g以上の強磁性合金粉末を用いることを特
徴とする磁気記録媒体。1. A magnetic recording medium comprising a non-magnetic support and a magnetic layer containing a ferromagnetic powder and a binder provided on a non-magnetic support.
An acicular γ-Al 2 O 3 powder having an axis ratio (major axis length / minor axis length) of 3 to 50 in the magnetic layer, and an Mohs hardness having an axis ratio (major axis length / minor axis length) of 2.5 or less Wherein the ferromagnetic powder contains a ferromagnetic alloy powder having an iron content of not less than 60% by weight and a specific surface area of not less than 40 m 2 / g. Medium.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7575388A JP2647123B2 (en) | 1988-03-29 | 1988-03-29 | Magnetic recording media |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7575388A JP2647123B2 (en) | 1988-03-29 | 1988-03-29 | Magnetic recording media |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01248318A JPH01248318A (en) | 1989-10-03 |
| JP2647123B2 true JP2647123B2 (en) | 1997-08-27 |
Family
ID=13585325
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7575388A Expired - Lifetime JP2647123B2 (en) | 1988-03-29 | 1988-03-29 | Magnetic recording media |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2647123B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2605464B2 (en) * | 1990-08-28 | 1997-04-30 | 松下電器産業株式会社 | Magnetic recording media |
| US5645917A (en) * | 1991-04-25 | 1997-07-08 | Fuji Photo Film Co., Ltd. | Magnetic recording medium |
-
1988
- 1988-03-29 JP JP7575388A patent/JP2647123B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01248318A (en) | 1989-10-03 |
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