JPH06301960A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium which does not wear magnetic heads much and has an excellent electromagnetic conversion characteristic and durability by optimizing the particle size and adding quantity of abrasive powder contained in the magnetic layer of the medium. CONSTITUTION:Abrasive powder having a mean particle size of 0.020.2mum is added by 35-70 pts.wt. to 100 pts.wt. pts. of ferromagnetic powder composed of the powder of a ferromagnetic metal having a high sigma. When the very fine abrasive powder and ferromagnetic powder are combinedly used, the adding amount of the abrasive powder can be increased while the wear of magnetic heads and the deterioration of electromagnetic conversion characteristic of this magnetic recording medium are suppressed and the running durability of the medium can be remarkably improved.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、オーディオ機器、ビデ
オ機器、或はコンピューターなどに用いる磁気記録媒体
に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium used in audio equipment, video equipment, computers and the like.

【０００２】[0002]

【従来の技術】近年磁気記録の分野においては、ビデオ
機器の高画質化の進行あるいはアナログ記録からデジタ
ル記録への記録方式の変化などにより、記録波長はどん
どん短くなっている。そのため、これらに用いられる強
磁性粉についても電磁変換特性の向上を狙い微粒子化が
進んでいるが、強磁性粉が微粒子になるほど磁気記録媒
体の磁性層の耐久性（スチル寿命、磁気ヘッドへの粉付
着、磁性層の粉落ち等）が悪化する。よって、磁性層の
耐久性向上のため結合剤樹脂、潤滑剤、研磨剤などの改
良が活発に行われている。2. Description of the Related Art In recent years, in the field of magnetic recording, the recording wavelength has become shorter and shorter due to the progress of higher image quality of video equipment and the change of recording system from analog recording to digital recording. Therefore, the ferromagnetic powder used for these is also becoming finer particles with the aim of improving the electromagnetic conversion characteristics. However, as the ferromagnetic powder becomes finer particles, the durability of the magnetic layer of the magnetic recording medium (still life, magnetic head (Powder adhesion, powder falling off of the magnetic layer, etc.) deteriorates. Therefore, in order to improve the durability of the magnetic layer, the binder resin, the lubricant, the abrasive and the like have been actively improved.

【０００３】[0003]

【発明が解決しようとする課題】近年の磁気記録媒体の
高密度記録化に伴い、磁気記録媒体に用いられる強磁性
粉の微粒子化は更に進み、さらにはヘッド−磁気記録媒
体間の相対速度も増加する傾向がある。よって、このこ
とによる磁気記録媒体の耐久性低下に対し研磨剤の影響
は大きく、種類、粒子径、添加量等様々な検討が行なわ
れている。With the recent trend toward higher density recording of magnetic recording media, the fine particles of ferromagnetic powder used in magnetic recording media have been further advanced, and the relative velocity between the head and the magnetic recording medium has also increased. Tends to increase. Therefore, the abrasive has a great influence on the decrease in durability of the magnetic recording medium due to this, and various studies such as the type, particle diameter, and addition amount have been made.

【０００４】ここで、研磨剤の添加量を増加すれば磁性
塗膜の強度は増加し、スチル寿命、粉落ちなどの耐久性
は向上するが、それに反して磁気ヘッドの磨耗量が大き
くなる。また、この磁気ヘッドの磨耗は、研磨剤の硬
度、粒子径が大きくなるほど多くなる。Here, if the amount of the abrasive added is increased, the strength of the magnetic coating film is increased and the durability such as the still life and powder falling is improved, but on the contrary, the wear amount of the magnetic head is increased. Further, the wear of the magnetic head increases as the hardness and particle size of the polishing agent increase.

【０００５】一方、高密度記録化に伴い短波長記録時の
間隙損失を少なくし電磁変換特性を向上するために磁性
層表面の粗さを小さくする必要がある。よって、粒子径
の大きな研磨剤や、またその添加量にも上限が生じてく
る。更にこれら研磨剤粒子は強磁性粉に対して比較的大
きく、強磁性粉の配向性を阻害し角型比、飽和磁束密度
等の磁気特性を低下させる。On the other hand, along with high density recording, it is necessary to reduce the surface roughness of the magnetic layer in order to reduce the gap loss during short wavelength recording and improve the electromagnetic conversion characteristics. Therefore, there is an upper limit on the abrasive having a large particle size and the addition amount thereof. Further, these abrasive particles are relatively large with respect to the ferromagnetic powder, and impede the orientation of the ferromagnetic powder to deteriorate the magnetic properties such as squareness ratio and saturation magnetic flux density.

【０００６】さらに、近年メタルテープの使用等に対応
するため合金ヘッド（アモルファスヘッドなど）を使用
する割合が多くなり、これらのヘッドとメタルテープの
組み合わせで使用した場合、金属−金属の摩擦によりヘ
ッドに焼き付きが生じ電磁変換特性が低下する。Further, in recent years, the proportion of alloy heads (amorphous heads, etc.) used has increased in order to cope with the use of metal tapes and the like. When these heads and metal tapes are used in combination, the heads are liable to be metal-metal friction. Seizure occurs and electromagnetic conversion characteristics deteriorate.

【０００７】このヘッド焼き付きは使用環境に左右さ
れ、低温低湿の環境下でよく起こる現象である。メタル
系磁性粉より研磨性の強い酸化鉄系磁性粉を用いた磁気
記録媒体でこの現象が起こらないことから磁性層の研磨
性が関係しており、磁性層の研磨性の検討が必要にな
る。The sticking of the head is a phenomenon which depends on the use environment and often occurs in an environment of low temperature and low humidity. This phenomenon does not occur in magnetic recording media using iron oxide-based magnetic powder, which is more abrasive than metal-based magnetic powder, so the abradability of the magnetic layer is related, and it is necessary to examine the abradability of the magnetic layer. .

【０００８】また、近年のカメラ一体型ビデオテープレ
コーダー、携帯用機器の発展に伴い機器の使用環境は低
温から高温まで、低湿から高湿まで範囲が非常に広がっ
ており、大きな課題となっている。Further, with the recent development of video tape recorders with built-in cameras and portable devices, the operating environment of the devices has greatly expanded from low temperature to high temperature, from low humidity to high humidity, which is a big problem. .

【０００９】そこで本発明は磁性層の研磨性を最適にす
ることによって、磁気ヘッドに対する影響の少ない、電
磁変換特性、走行耐久性などに優れた磁気記録媒体を提
供することを目的とする。Therefore, an object of the present invention is to provide a magnetic recording medium which has little influence on a magnetic head and is excellent in electromagnetic conversion characteristics and running durability by optimizing the polishing property of a magnetic layer.

【００１０】[0010]

【課題を解決するための手段】この目的を達成するため
本発明は、平均粒子サイズが０．０２μｍ以上０．２μ
ｍ以下の研磨剤を少なくとも１種類含み、その含有量を
強磁性金属粉末１００重量部に対して３５重量部以上７
０重量部以下とする。To achieve this object, the present invention has an average particle size of 0.02 μm or more and 0.2 μm or more.
At least one type of abrasive having a particle size of m or less is contained, and the content thereof is 35 parts by weight or more and 7 parts by weight with respect to 100 parts by weight of the ferromagnetic metal powder.
It is 0 parts by weight or less.

【００１１】[0011]

【作用】本発明の特徴とする研磨剤を用いることによ
り、その平均粒子サイズが０．２μｍ以下の微粒子であ
るため、個々の研磨力は大きくなく、その結果ヘッド摩
耗が抑えられ、磁性層中にこれらの研磨剤を多く添加さ
せることが可能となる。さらに、微粒子であるため研磨
剤粒子の個数が非常に多く、磁性層塗膜に万遍なく存在
することができる。これらの結果、塗膜強度が向上しス
チル寿命等の耐久性の改善ができ、またこの磁性層塗膜
表面は適度なヘッドクリーニング性を有し、メタルテー
プ−合金ヘッド間のヘッドの焼き付きに関しても改善で
き、ヘッドの摩耗にも悪影響を与えない。そして更に粒
子径が小さいために磁性層表面の粗さの悪化、強磁性粉
の配向性を乱すなどの課題についても解決できる。By using the abrasive agent which is a feature of the present invention, since the average particle size is 0.2 μm or less, the individual polishing force is not large, and as a result, head wear is suppressed and It is possible to add a large amount of these abrasives to the. Furthermore, since they are fine particles, the number of abrasive particles is very large, and they can be evenly present in the magnetic layer coating film. As a result, the strength of the coating film is improved and the durability such as the still life can be improved. Further, the surface of the coating film of the magnetic layer has an appropriate head cleaning property, and the seizure of the head between the metal tape and the alloy head can be achieved. It can be improved and does not adversely affect the wear of the head. Further, since the particle diameter is smaller, problems such as deterioration of the surface roughness of the magnetic layer and disturbance of the orientation of the ferromagnetic powder can be solved.

【００１２】また、強磁性粉として酸化鉄磁性粉等と比
べてσsが高い強磁性金属粉末を使用することで、研磨
剤の添加による電磁変換特性の悪化を防ぐことが可能と
なる。Further, by using a ferromagnetic metal powder having a higher σs than the iron oxide magnetic powder as the ferromagnetic powder, it is possible to prevent deterioration of electromagnetic conversion characteristics due to addition of an abrasive.

【００１３】よって、本発明の特徴とする研磨剤を添加
することにより、ヘッド磨耗を増加させず耐久性を向上
出来るとともに、磁性層表面粗さ、磁気特性、磁気ヘッ
ドのクリーニング性に優れた電磁変換特性の良好な磁気
記録媒体が得られる。Therefore, by adding the polishing agent which is the feature of the present invention, it is possible to improve the durability without increasing the head wear, and at the same time, to improve the magnetic layer surface roughness, the magnetic characteristics and the magnetic head cleaning property. A magnetic recording medium having good conversion characteristics can be obtained.

【００１４】[0014]

【実施例】以下、本発明の実施例について述べる。EXAMPLES Examples of the present invention will be described below.

【００１５】（実施例１） 非磁性支持体 ポリエチレンテレフタレートフィルム 厚み １０μｍ 磁性塗料の組成 強磁性金属粉末 １００重量部 カーボンブラック （粒子径 ０．０２μｍ） １重量部 研磨剤 ５０重量部 ポリ塩化ビニル系樹脂 ９重量部 ポリウレタン樹脂 ９重量部 潤滑剤 ミリスチン酸 ２重量部 ステアリン酸 １重量部 ｎ−ブチルステアレート １重量部 硬化剤 ポリイソシアネート ４重量部 ここで、強磁性粉として強磁性合金粉（比表面積(BET
法)５５ｍ²／ｇ，保磁力１．２１×１０⁵Ａ／ｍ）、研
磨剤として平均サイズ０．１μｍのα−Ｆｅ2Ｏ3を使用
した。Example 1 Non-magnetic support Polyethylene terephthalate film Thickness 10 μm Composition of magnetic paint Ferromagnetic metal powder 100 parts by weight Carbon black (particle diameter 0.02 μm) 1 part by weight Abrasive 50 parts by weight Polyvinyl chloride resin 9 parts by weight Polyurethane resin 9 parts by weight Lubricant Myristic acid 2 parts by weight Stearic acid 1 part by weight n-Butyl stearate 1 part by weight Curing agent Polyisocyanate 4 parts by weight Here, ferromagnetic alloy powder as ferromagnetic powder (specific surface area ( BET
Method) 55 m ² / g, coercive force 1.21 × 10 ⁵ A / m), and α-Fe 2 O 3 having an average size of 0.1 μm was used as an abrasive.

【００１６】（比較例１）実施例１と比較するために、
研磨剤の全添加量を３０重量部として試験サンプルを作
製した。Comparative Example 1 For comparison with Example 1,
A test sample was prepared with the total amount of the abrasive added being 30 parts by weight.

【００１７】（比較例２）実施例１と比較するために、
研磨剤の全添加量を７５重量部として試験サンプルを作
製した。Comparative Example 2 For comparison with Example 1,
A test sample was prepared with the total amount of abrasive added being 75 parts by weight.

【００１８】（実施例２）実施例１において、研磨剤の
全添加量を４０重量部として試験サンプルを作製した。Example 2 A test sample was prepared in the same manner as in Example 1, except that the total amount of abrasive added was 40 parts by weight.

【００１９】（比較例３）実施例１と比較するために、
研磨剤として平均粒子サイズ０．２μｍのα−Ｆｅ2Ｏ3
を３０重量部添加した試験サンプルを作製した。Comparative Example 3 For comparison with Example 1,
Α-Fe2O3 with an average particle size of 0.2 μm as an abrasive
Was added to prepare a test sample.

【００２０】（比較例４）実施例１と比較するために、
研磨剤として平均粒子サイズ０．０１μｍのα−Ｆｅ2
Ｏ3を３０重量部添加した試験サンプルを作製した。(Comparative Example 4) In order to compare with Example 1,
Α-Fe2 with an average particle size of 0.01 μm as an abrasive
A test sample was prepared by adding 30 parts by weight of O3.

【００２１】（実施例３）実施例１の研磨剤を平均粒子
０．０３μｍのα−Ｆｅ2Ｏ3とし、それ以外は実施例１
と同様の試験サンプルを作製した。(Example 3) The abrasive of Example 1 was α-Fe2O3 having an average particle size of 0.03 μm, and other than that Example 1
A test sample similar to the above was prepared.

【００２２】（実施例４）実施例１の研磨剤を平均粒子
０．０８μｍのルチル型ＴｉＯ2とし、それ以外は実施
例１と同様の試験サンプルを作製した。Example 4 A rutile-type TiO 2 having an average particle size of 0.08 μm was used as the polishing agent of Example 1 and a test sample similar to that of Example 1 was prepared.

【００２３】（実施例５）実施例１の研磨剤を平均粒子
０．１２μｍのＺｎＯ2とし、それ以外は実施例１と同
様の試験サンプルを作製した。Example 5 A test sample was prepared in the same manner as in Example 1 except that the abrasive used in Example 1 was ZnO 2 having an average particle size of 0.12 μm.

【００２４】以上の実施例、比較例において塗料の作製
方法は一定で、磁性塗料の組成から潤滑剤、硬化剤を除
いた混合物にメチルエチルケトン／トルエン／シクロヘ
キサノンの混合溶剤（重量比３／３／１）を添加して適
度な粘度とし、混練機に加圧ニーダ、分散機にサンドミ
ルを使用して磁性粉を充分混練分散する。その後、上記
組成になるように潤滑剤、硬化剤を添加し、混合溶剤に
よって固形分比率３５重量％の塗工用磁性塗料を調整す
る。In the above Examples and Comparative Examples, the method of preparing the coating composition was constant, and a mixture of the composition of the magnetic coating composition excluding the lubricant and the curing agent was mixed with methyl ethyl ketone / toluene / cyclohexanone mixed solvent (weight ratio: 3/3/1). ) Is added to obtain an appropriate viscosity, and the magnetic powder is sufficiently kneaded and dispersed using a pressure kneader in a kneader and a sand mill in a disperser. Then, a lubricant and a curing agent are added so as to have the above composition, and a magnetic coating material having a solid content ratio of 35% by weight is prepared with a mixed solvent.

【００２５】この磁性塗料を非磁性支持体上に、乾燥後
膜厚２．５μｍになるように、塗布・乾燥後カレンダー
処理をおこなう。その後磁性層と反対面上にカーボンブ
ラックと結合剤樹脂を主体としたバックコート層を膜厚
０．６μｍなるように形成し、６０℃，３６時間のエー
ジング処理を行う。その後１／２インチ幅に裁断し、Ｖ
ＨＳ方式カセットとして試作サンプルとした。This magnetic coating material is applied on a non-magnetic support so that the film thickness after drying is 2.5 μm, and calendering is carried out after coating and drying. After that, a back coat layer mainly containing carbon black and a binder resin is formed on the surface opposite to the magnetic layer so as to have a film thickness of 0.6 μm, and aging treatment is performed at 60 ° C. for 36 hours. Then cut into 1/2 inch width, V
The HS type cassette was used as a prototype sample.

【００２６】これらの試作サンプルについて後述する方
法によって、磁性層の静磁気特性、スチル寿命テスト、
Ｃ／Ｎの評価試験、繰り返し走行テストを行なった。評
価結果について（表１）に示す。The magnetostatic properties of the magnetic layer, the still life test, and
A C / N evaluation test and a repeated running test were performed. The evaluation results are shown in (Table 1).

【００２７】[0027]

【表１】 [Table 1]

【００２８】（表１）より明らかなように、粒子サイズ
０．１μｍのα−Ｆｅ2Ｏ3を使用したとき、（比較例
１）の３０重量部ではスチル寿命が短く、繰り返し走行
後のＣ／Ｎの劣化も大きく、媒体としての走行耐久性が
悪い。また（比較例２）の７５重量部ではヘッド摩耗が
大きくかつ静磁気特性および電磁変換特性（Ｃ／Ｎ）が
悪化している。しかし、（実施例１）の５０重量部、
（実施例２）の４０重量部では、電磁変換特性（Ｃ／
Ｎ）も良好で、かつヘッド摩耗量が小さいもののスチル
寿命が長く、ヘッドのクリーニング性も良好で繰り返し
走行後のＣ／Ｎの低下も見られない。As is clear from (Table 1), when α-Fe2O3 having a particle size of 0.1 μm was used, the still life was short at 30 parts by weight of (Comparative Example 1), and the C / N ratio after repeated running was reduced. Deterioration is large and running durability as a medium is poor. At 75 parts by weight of (Comparative Example 2), head wear was large and the magnetostatic characteristics and electromagnetic conversion characteristics (C / N) were poor. However, 50 parts by weight of (Example 1),
In 40 parts by weight of (Example 2), the electromagnetic conversion characteristic (C /
N) is also good, and although the head wear amount is small, the still life is long, the head cleaning property is good, and the decrease in C / N after repeated running is not observed.

【００２９】次に、粒子サイズが、０．２μｍの（比較
例３）、０．１μｍの（実施例１）、０．０３μｍの
（実施例３）、０．０１μｍの（比較例４）と異なるサ
ンプルをみると、（実施例１）および（実施例３）では
良好な結果が得られているが、（比較例３）では粒子サ
イズが大きいためヘッドに対する研磨性が大きすぎるた
め、ヘッド摩耗量が大きく、磁性層の表面性の悪化によ
る電磁変換特性（Ｃ／Ｎ）の悪化が見られる。一方、
（比較例４）では粒子サイズが小さすぎるため、同一の
分散手法では分散が不十分になり、静磁気特性、電磁変
換特性（Ｃ／Ｎ）、耐久性ともに悪化している。Next, the particle size was 0.2 μm (Comparative Example 3), 0.1 μm (Example 1), 0.03 μm (Example 3), and 0.01 μm (Comparative Example 4). Looking at different samples, good results were obtained in (Example 1) and (Example 3), but in (Comparative Example 3), the abrasiveness to the head was too large due to the large particle size, and therefore the head wear The amount is large, and the electromagnetic conversion characteristics (C / N) are deteriorated due to the deterioration of the surface property of the magnetic layer. on the other hand,
In (Comparative Example 4), the particle size was too small, so that the dispersion was insufficient with the same dispersion method, and the magnetostatic property, the electromagnetic conversion property (C / N), and the durability were deteriorated.

【００３０】また、（実施例１）から研磨剤の種類のみ
を変えた（実施例４）および（実施例５）ともに、（実
施例１）と同様に良好な結果が得られている。In addition, in (Example 4) and (Example 5) in which only the kind of the abrasive was changed from (Example 1), good results were obtained as in (Example 1).

【００３１】これらの（表１）の結果より、０．０２μ
ｍから０．２μｍの粒子サイズの研磨剤を３５重量部か
ら７０重量部の範囲で添加するのが好ましい。From these results (Table 1), 0.02μ
It is preferable to add an abrasive having a particle size of m to 0.2 μm in the range of 35 to 70 parts by weight.

【００３２】なお、各サンプルの評価方法は以下の通り
である。 （１）磁性層の静磁気特性 東英工業（株）製振動試料型磁力計を用いて磁性層の飽
和磁束密度、角形比を測定した。 （２）スチル寿命テスト ＶＨＳ−Ｃ方式ビデオムービー（松下電器産業（株）
製、型式ＮＶ−Ｍ１０）を用い、−１０℃の環境下で試
験サンプルのスチル寿命を測定した。寿命は記録したテ
ストパターンを再生し、スチル状態としてから計時を開
始し映像が乱れるまでの時間を寿命とした。測定は５回
行い、それらの平均を寿命とした。また測定の最長は６
０分までとした。ただしビデオムービーのスチル解除機
能は削除している。 （３）Ｃ／Ｎの評価試験 ＶＨＳ方式ビデオテープレコーダー（松下電器産業
（株）製、型式ＮＶ−ＦＳ９００）を用いて試験サンプ
ルの７ＭＨｚ±１ＭＨｚのＣ／Ｎの測定を行なった。た
だし、比較例１で得られた試験サンプルを、基準（±０
ｄＢ）として相対比較を行なった。 （４）繰り返し走行テスト ＶＨＳ方式ビデオテープレコーダー（松下電器産業
（株）製、型式ＮＶ−ＦＳ９００）用い、各試験サンプ
ル（ＶＨＳで１２０分のテープ長）を４０℃，８０％Ｒ
Ｈの環境下で１００パスの走行（３．３ｃｍ／秒）試験
を行ない、走行テスト前後のビデオテープレコーダーの
磁気ヘッドの突き出し量を測定しヘッド摩耗量を算出し
た。また磁気ヘッドの汚れ状態を観察した。The evaluation method of each sample is as follows. (1) Magnetostatic properties of magnetic layer The saturation magnetic flux density and squareness ratio of the magnetic layer were measured using a vibrating sample magnetometer manufactured by Toei Industry Co., Ltd. (2) Still life test VHS-C method video movie (Matsushita Electric Industrial Co., Ltd.)
Manufactured by Model NV-M10) was used to measure the still life of the test sample in an environment of -10 ° C. The life was defined as the time from the time when the recorded test pattern was reproduced and the still state was started to the time measurement until the image was disturbed. The measurement was performed 5 times, and the average thereof was used as the life. The longest measurement is 6
It was set to 0 minutes. However, the still-release function for video movies has been deleted. (3) C / N evaluation test The C / N of 7 MHz ± 1 MHz of the test sample was measured using a VHS system video tape recorder (Model NV-FS900, manufactured by Matsushita Electric Industrial Co., Ltd.). However, the test sample obtained in Comparative Example 1 was used as a reference (± 0
Relative comparison was made as dB). (4) Repeated running test Using a VHS video tape recorder (Matsushita Electric Industrial Co., Ltd., model NV-FS900), each test sample (tape length of 120 minutes at VHS) was 40 ° C, 80% R.
A 100-pass running (3.3 cm / sec) test was performed in an H environment, and the amount of protrusion of the magnetic head of the video tape recorder before and after the running test was measured to calculate the amount of head wear. Moreover, the dirt state of the magnetic head was observed.

【００３３】また、同様に各試験サンプルを２３℃、相
対湿度１０％の常温、低湿度環境下で５０パスの繰り返
し走行を行なった。その前後の７ＭＨｚ±１ＭＨｚのＣ
／Ｎ測定結果からヘッドの焼き付きによるＣ／Ｎの低下
を見た。Similarly, each test sample was repeatedly run for 50 passes in a normal temperature and low humidity environment at 23 ° C. and a relative humidity of 10%. C of 7MHz ± 1MHz before and after that
From the results of the / N measurement, it was found that the C / N was reduced due to the seizure of the head.

【００３４】[0034]

【発明の効果】以上詳述したように本発明の磁気記録媒
体は、ヘッド摩耗、ヘッドの焼き付き等の磁気ヘッドへ
の悪影響が非常に少ないうえ、スチル寿命、走行耐久
性、電磁変換特性に優れた磁気記録媒体を提供すること
ができ、その実用上の価値は大なるものである。As described in detail above, the magnetic recording medium of the present invention has very little adverse effects on the magnetic head such as head wear and head burn-in, and is excellent in still life, running durability and electromagnetic conversion characteristics. The magnetic recording medium can be provided, and its practical value is great.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 橘高 正信 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masanobu Tachibana 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】非磁性支持体上に強磁性金属粉末と結合剤
とを主体とした磁性層を形成してなる磁気記録媒体であ
って、上記磁性層に添加される研磨剤として、平均粒子
サイズが０．０２μｍ以上０．２μｍ以下の研磨剤を少
なくとも１種類以上含み、上記研磨剤の添加量が上記強
磁性金属粉末１００重量部に対して３５重量部以上７０
重量部以下であることを特徴とする磁気記録媒体。1. A magnetic recording medium comprising a magnetic layer mainly composed of a ferromagnetic metal powder and a binder on a non-magnetic support, wherein an average particle is used as an abrasive added to the magnetic layer. At least one abrasive having a size of 0.02 μm or more and 0.2 μm or less is contained, and the amount of the abrasive added is 35 parts by weight or more and 70 parts by weight or more per 100 parts by weight of the ferromagnetic metal powder.
A magnetic recording medium characterized by being less than or equal to parts by weight.