JPH01320631A - Magnetic recording medium - Google Patents
Magnetic recording mediumInfo
- Publication number
- JPH01320631A JPH01320631A JP15437588A JP15437588A JPH01320631A JP H01320631 A JPH01320631 A JP H01320631A JP 15437588 A JP15437588 A JP 15437588A JP 15437588 A JP15437588 A JP 15437588A JP H01320631 A JPH01320631 A JP H01320631A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- magnetic powder
- iron oxide
- weight
- cobalt
- 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
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims abstract description 50
- 239000006247 magnetic powder Substances 0.000 claims abstract description 43
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 26
- 238000004438 BET method Methods 0.000 claims abstract description 15
- 230000005415 magnetization Effects 0.000 claims abstract description 12
- 239000002184 metal Substances 0.000 claims abstract description 10
- 229910052751 metal Inorganic materials 0.000 claims abstract description 10
- 229910017052 cobalt Inorganic materials 0.000 claims description 12
- 239000010941 cobalt Substances 0.000 claims description 12
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 12
- 229910052742 iron Inorganic materials 0.000 claims description 12
- 238000006243 chemical reaction Methods 0.000 abstract description 6
- 239000000843 powder Substances 0.000 abstract description 4
- 238000013329 compounding Methods 0.000 abstract 1
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 239000003973 paint Substances 0.000 description 11
- 239000000203 mixture Substances 0.000 description 8
- 229920005989 resin Polymers 0.000 description 7
- 239000011347 resin Substances 0.000 description 7
- 229910000859 α-Fe Inorganic materials 0.000 description 7
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000003960 organic solvent Substances 0.000 description 3
- 229920002554 vinyl polymer Polymers 0.000 description 3
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 239000012948 isocyanate Substances 0.000 description 2
- -1 isocyanate compounds Chemical class 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229920006267 polyester film Polymers 0.000 description 2
- 229920005749 polyurethane resin Polymers 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- TWJNQYPJQDRXPH-UHFFFAOYSA-N 2-cyanobenzohydrazide Chemical compound NNC(=O)C1=CC=CC=C1C#N TWJNQYPJQDRXPH-UHFFFAOYSA-N 0.000 description 1
- NTIZESTWPVYFNL-UHFFFAOYSA-N Methyl isobutyl ketone Chemical compound CC(C)CC(C)=O NTIZESTWPVYFNL-UHFFFAOYSA-N 0.000 description 1
- UIHCLUNTQKBZGK-UHFFFAOYSA-N Methyl isobutyl ketone Natural products CCC(C)C(C)=O UIHCLUNTQKBZGK-UHFFFAOYSA-N 0.000 description 1
- TUNFSRHWOTWDNC-UHFFFAOYSA-N Myristic acid Natural products CCCCCCCCCCCCCC(O)=O TUNFSRHWOTWDNC-UHFFFAOYSA-N 0.000 description 1
- 235000021360 Myristic acid Nutrition 0.000 description 1
- 229920002433 Vinyl chloride-vinyl acetate copolymer Polymers 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000002216 antistatic agent Substances 0.000 description 1
- 239000012461 cellulose resin Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920002037 poly(vinyl butyral) polymer Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
Landscapes
- Paints Or Removers (AREA)
- Magnetic Record Carriers (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は磁気記録媒体に関し、さらに詳しくは電磁変
換特性に優れたビデオテープなどの磁気記録媒体に関す
る。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium, and more particularly to a magnetic recording medium such as a video tape having excellent electromagnetic conversion characteristics.
磁気記録媒体は、通常、磁性粉末を結合剤樹脂とともに
ポリエステルフィルムなどの基体上に塗着してつくられ
、高性能が要求される場合は酸化物系磁性粉末に比して
高い保磁力を有する金属鉄磁性粉末が用いられる。Magnetic recording media are usually made by applying magnetic powder together with a binder resin onto a substrate such as a polyester film, and when high performance is required, it has a higher coercive force than oxide-based magnetic powder. Metallic iron magnetic powder is used.
しかしながら、フェライト系磁気ヘッドを用いるＶＴＲ
においては、使用するビデオテープの保磁力が１０００
エルステッドより大きいと磁気記録が良好に行えないた
め、ビデオテープの保磁力を１０００エルステッド以下
にしなければならない。However, VTRs using ferrite magnetic heads
In this case, the coercive force of the videotape used is 1000
If it is larger than Oe, magnetic recording cannot be performed well, so the coercive force of the video tape must be 1000 Oe or less.
しかして、この種のビデオテープに使用する磁性粉末は
、保磁力が９００エルステッド以下のものでなければな
らず、この種のビデオテープに金属鉄磁性粉末を使用し
ようとすれば、飽和磁化量を１００ ｅｍｕ／ ｇ以下
にするか、ＢＥＴ法による比表面積を４０ｍ２／ｇ以下
にするかして、金属鉄磁性粉末の保磁力を９００エルス
テッド以下にしなければならない。However, the magnetic powder used in this type of videotape must have a coercive force of 900 oers or less, and if metal iron magnetic powder is to be used in this type of videotape, the amount of saturation magnetization must be reduced. The coercive force of the metallic iron magnetic powder must be 900 oersted or less, either by making it 100 emu/g or less, or by making the specific surface area by the BET method 40 m2/g or less.
［発明が解決しようとする課Ｈ］
ところが、飽和磁化量を１００ ｅｍｕ／ ｇ以上にし
たのでは、酸化鉄磁性粉末を使用する場合と同じで出力
を充分に高くすることができず、また、ＢＥＴ法による
比表面積を４０ｍ２／ｇ以下にすると、結合剤樹脂に対
する分散性が悪くなり、ノイズが高くなって、良好な電
磁変換特性が得られない。[Problem H to be solved by the invention] However, if the saturation magnetization amount is set to 100 emu/g or more, the output cannot be made sufficiently high as in the case of using iron oxide magnetic powder, and also, If the specific surface area determined by the BET method is 40 m2/g or less, the dispersibility in the binder resin will be poor, noise will be high, and good electromagnetic conversion characteristics cannot be obtained.
〔課題を解決するための手段］
この発明は、かかる問題を解消するため種々検討を行っ
た結果なされたもので、保磁力が７００〜９００エルス
テッドのコバルト含有酸化鉄磁性粉末を併用することに
よって、飽和磁化量が１０ＱｅｌＩｕ／ｇ以上で、ＢＥ
Ｔ法による比表面積が４０％／ｇ以下の金属鉄磁性粉末
の分散性を改善し、これらの磁性粉末を併用して得られ
る磁気記録媒体の出力を高くし、ノイズを充分に低減し
て電磁変換特性を充分に向上させたものである。[Means for Solving the Problems] This invention was made as a result of various studies to solve these problems, and by using cobalt-containing iron oxide magnetic powder with a coercive force of 700 to 900 Oe, When the saturation magnetization amount is 10 QelIu/g or more, BE
By improving the dispersibility of metallic iron magnetic powders with a specific surface area of 40%/g or less by the T method, the output of magnetic recording media obtained by using these magnetic powders in combination is increased, and the noise is sufficiently reduced to improve electromagnetic performance. It has sufficiently improved conversion characteristics.
この発明で使用される金属鉄磁性粉末は、飽和磁化量が
１００ ｅｍｕ／ ｇ以上で、ＢＥＴ法による比表面積
が４０ｍ２／ｇ以下のものであることが好ましく、飽和
磁化量が１００ ｅｍｕ／ ｇより小さいものでは酸化
鉄磁性粉末と同じになってしまって、高い出力が得られ
ない。また、ＢＥＴ法による比表面積は４０ｒｄ／ｇ以
下にしなければ、保磁力を９００エルステッド以下にす
ることができず、フェライトヘッドを用いたＶＴＲに使
用するビデオテープの磁性粉末として使用することがで
きない。The metal iron magnetic powder used in this invention preferably has a saturation magnetization of 100 emu/g or more and a specific surface area of 40 m2/g or less by the BET method, and preferably has a saturation magnetization of 100 emu/g or more. If it is small, it becomes the same as iron oxide magnetic powder, and high output cannot be obtained. In addition, unless the specific surface area by the BET method is 40rd/g or less, the coercive force cannot be reduced to 900 Oe or less, and it cannot be used as a magnetic powder for video tapes used in VTRs using ferrite heads.
また、併用されるコバルト含有酸化鉄磁性粉末は、ＢＥ
Ｔ法による比表面積が４０ｍ２／ｇ以上の酸化鉄磁性粉
末の表面にコバルトを含む磁性酸化鉄層を形成した保磁
力が７００〜９００エルステッドのものであることが好
ましく、この種のＢＥＴ法による比表面積が４０ｒｒｒ
／ｇ以上の酸化鉄磁性粉末の表面にコバルトを含む磁性
酸化鉄層を形成したコバルト含有酸化鉄磁性粉末は、結
合剤樹脂に対する分散性がよく、この良好な分散性によ
って併用する飽和磁化量がＩ Ｑ Ｏｅｒａｕ／ｇ以上
で、ＢＥＴ法による比表面積が４０％／ｇ以下の金属鉄
磁性粉末の分散性が改善され、ノイズが充分に低減され
る。また、保磁力が７００〜９００エルステッドである
ため、併用する金属鉄磁性粉末と相乗的に作用して高い
出力が得られ、角型も向上される。In addition, the cobalt-containing iron oxide magnetic powder used in combination is BE
It is preferable that a magnetic iron oxide layer containing cobalt is formed on the surface of an iron oxide magnetic powder having a specific surface area of 40 m2/g or more by the T method and a coercive force of 700 to 900 Oe. Surface area is 40rrr
The cobalt-containing iron oxide magnetic powder, which has a cobalt-containing magnetic iron oxide layer formed on the surface of the iron oxide magnetic powder with a weight of /g or more, has good dispersibility in the binder resin, and due to this good dispersibility, the amount of saturation magnetization used in combination can be reduced. When I Q Oerau/g or more, the dispersibility of metal iron magnetic powder having a specific surface area of 40%/g or less by the BET method is improved, and noise is sufficiently reduced. In addition, since the coercive force is 700 to 900 Oe, it acts synergistically with the metal iron magnetic powder used in combination, resulting in high output and improved squareness.
このような飽和磁化量が１００ ｅｍｕ／ ｇ以上で、
ＢＥＴ法による比表面積が４０％／ｇ以下の金属鉄磁性
粉末と、ＢＥＴ法による比表面積が４０ｒｄ／ｇ以上で
保磁力が７００〜９００エルステッドのコバルト含有酸
化鉄磁性粉末との配合割合は、出力を充分に高くし、ノ
イズを充分に低減するため、重量比で３ニア〜７：３の
範囲内にするのが好ましい。When the saturation magnetization amount is 100 emu/g or more,
The blending ratio of metallic iron magnetic powder with a specific surface area of 40%/g or less by the BET method and cobalt-containing iron oxide magnetic powder with a specific surface area of 40rd/g or more and a coercive force of 700 to 900 Oe by the BET method is determined by the output. In order to make the ratio sufficiently high and to sufficiently reduce noise, it is preferable that the weight ratio be within the range of 3 to 7:3.
この発明の磁気記録媒体を製造するには、常法に準じて
行えばよく、たとえば、飽和磁化量が１００ ｅｍｕ／
ｇ以上で、ＢＥＴ法による比表面積が４０ｍ２／ｇ以
下の金属鉄磁性粉末と、ＢＥＴ法による比表面積が４０
ｍ２／ｇ以上で保磁力が７００〜９００エルステッドの
コバルト含有酸化鉄磁性粉末とを、結合剤樹脂、有機溶
剤等とともに混合分散して磁性塗料を調製し、この磁性
塗料をポリエステルフィルムなどの基体上に、ロールコ
ータ−など任意の塗布手段によって、塗布し、乾燥すれ
ばよい。The magnetic recording medium of the present invention can be manufactured according to a conventional method, for example, when the saturation magnetization is 100 emu/
g or more and a specific surface area of 40 m2/g or less by the BET method, and a metal iron magnetic powder with a specific surface area of 40 m2/g or less by the BET method.
A magnetic paint is prepared by mixing and dispersing cobalt-containing iron oxide magnetic powder with a coercive force of 700 to 900 Oe over m2/g and a binder resin, an organic solvent, etc., and this magnetic paint is coated on a substrate such as a polyester film. Then, it may be applied by any coating means such as a roll coater and dried.
ここに用いる結合剤樹脂としては、塩化ビニル−酢酸ビ
ニル系共重合体ミボリビニルブチラール樹脂、繊維素系
樹脂、ポリウレタン系樹脂、イソシアネート化合物、放
射線硬化型樹脂など従来汎用されている結合剤樹脂が広
く使用される。The binder resins used here include conventionally widely used binder resins such as vinyl chloride-vinyl acetate copolymer miborvinyl butyral resin, cellulose resins, polyurethane resins, isocyanate compounds, and radiation-curable resins. Widely used.
また、有機溶剤としては、シクロヘキサノン、メチルイ
ソブチルケトン、メチルエチルケトン、トルエン、酢酸
エチル、テトラヒドロフランなど、従来から汎用されて
いる有機溶剤が、単独または二種以上混合して使用され
る。Further, as the organic solvent, conventionally widely used organic solvents such as cyclohexanone, methyl isobutyl ketone, methyl ethyl ketone, toluene, ethyl acetate, and tetrahydrofuran are used alone or in a mixture of two or more.
なお、磁性塗料中には通常使用されている各種添加剤、
たとえば、潤滑剤、研磨剤、帯電防止剤などを任意に添
加使用してもよい。In addition, various additives commonly used in magnetic paints,
For example, a lubricant, an abrasive, an antistatic agent, etc. may be optionally added.
次に、この発明の実施例について説明する。 Next, embodiments of the invention will be described.
実施例１
α−ＦｅＴｌｉ性粉末（ＢＥＴ法に ５０．０重量部よ
る比表面積３５Ｍ７ｇ、飽和磁
化量１１５ｅｍｕ／ｇ、保磁力８７０エルステッド）
コバルト被着酸化鉄磁性粉末 ＳＯ，Ｏ〃（ＢＥＴ法
による比表面積４９
ｒｒｒ／ｇ、飽和［７６ｅｍｕ／ｇ 、保磁力８００エ
ルステッド）
塩化ビニル−酢酸ビニル−ビニ １２．５ 〃ルアル
コール共重合体
ポリウレタン樹脂 １０．０ 〃イソシ
アネート化合物 ２．５〃α−Ａｌｔｏ、
６．ＯＮ（平均粒子径０．３μｍ）
ミリスチン酸 １．Ｏ〃シクロへキサ
ノン １１７．０ 〃トルエン
１１７．０ 〃これらの組成物をボール
ミル中で４８時間分散混合して磁性塗料を調製し、この
磁性塗料を１４μｍｆｆのポリエステルベースフィルム
上に、乾燥厚が５μｍとなるように塗布、乾燥し、表面
処理を行った後、所定の巾に裁断してビデオテープを作
成した。Example 1 α-FeTli powder (specific surface area 35M7g, saturation magnetization 115 emu/g, coercive force 870 oersteds by 50.0 parts by weight by BET method) Cobalt-coated iron oxide magnetic powder SO,O (ratio by BET method) Surface area 49 rrr/g, saturation [76 emu/g, coercive force 800 oersted] Vinyl chloride-vinyl acetate-vinyl 12.5 Alcohol copolymer polyurethane resin 10.0 Isocyanate compound 2.5 α-Alto,
6. ON (average particle size 0.3 μm) myristic acid 1. O〃Cyclohexanone 117.0〃Toluene
117.0 A magnetic paint was prepared by dispersing and mixing these compositions in a ball mill for 48 hours, and this magnetic paint was applied onto a 14 μmff polyester base film to a dry thickness of 5 μm, dried, and the surface was coated. After processing, the tape was cut to a predetermined width to create a videotape.
実施例２
実施例１における磁性塗料の組成において、α−Ｆｅｆ
Ｉｉ性粉末の使用量を５０．０重量部から７０．０重量
部に変更し、Ｃｏ被着酸化鉄磁性粉末の使用量を５０．
０重量部から３０．０重量部に変更した以外は、実施例
１と同様にしてビデオテープを作成した。Example 2 In the composition of the magnetic paint in Example 1, α-Fef
The amount of Ii powder used was changed from 50.0 parts by weight to 70.0 parts by weight, and the amount of Co-coated iron oxide magnetic powder was changed to 50.0 parts by weight.
A videotape was produced in the same manner as in Example 1 except that the amount was changed from 0 parts by weight to 30.0 parts by weight.
実施例３
実施例１における磁性塗料の組成において、α−Ｆｅ磁
性粉末の使用量を５０．０重量部から３０．０重量部に
変更し、Ｃｏ被着酸化鉄磁性粉末の使用量を５０．０重
量部から７０．０重量部に変更した以外は、実施例１と
同様にしてビデオテープを作成した。Example 3 In the composition of the magnetic paint in Example 1, the amount of α-Fe magnetic powder used was changed from 50.0 parts by weight to 30.0 parts by weight, and the amount of Co-coated iron oxide magnetic powder was changed to 50.0 parts by weight. A videotape was produced in the same manner as in Example 1 except that the amount was changed from 0 parts by weight to 70.0 parts by weight.
比較例１ ・、：）実
施例１における磁性塗料の組成において、α□−Ｆ ｅ
磁性粉末の使用量を５０．０重量部から８０．０重量部
に変更し、Ｃｏ被着酸化鉄磁性粉末の使用量を５０．０
重量部から２０．０重量部に変更した以外は、実施例１
と同様にしてビデオテープを作成した。Comparative Example 1 ・,:) In the composition of the magnetic paint in Example 1, α□-F e
The amount of magnetic powder used was changed from 50.0 parts by weight to 80.0 parts by weight, and the amount of Co-coated iron oxide magnetic powder was changed to 50.0 parts by weight.
Example 1 except that parts by weight were changed to 20.0 parts by weight.
A videotape was created in the same manner.
比較例２
実施例１における磁性塗料の組成において、α−Ｆｅ磁
性粉末の使用量を５０．０重量部から２０．０重量部に
変更し、Ｃｏ被着酸化鉄磁性粉末の使用量を５０．０重
量部から８０．０重量部に変更した以外は、実施例１と
同様にしてビデオテープを作成した。Comparative Example 2 In the composition of the magnetic paint in Example 1, the amount of α-Fe magnetic powder used was changed from 50.0 parts by weight to 20.0 parts by weight, and the amount of Co-coated iron oxide magnetic powder was changed to 50.0 parts by weight. A videotape was produced in the same manner as in Example 1 except that the amount was changed from 0 parts by weight to 80.0 parts by weight.
比較例３
実施例１における磁性塗料の組成において、α−Ｆｅ磁
性粉末を省き、Ｃｏ被着酸化鉄磁性粉末の使用量を５０
．０重量部から１００．０重量部に変更した以外は、実
施例１と同様にしてビデオテープを作成した。Comparative Example 3 In the composition of the magnetic paint in Example 1, α-Fe magnetic powder was omitted, and the amount of Co-coated iron oxide magnetic powder was reduced to 50%.
．． A videotape was produced in the same manner as in Example 1 except that the amount was changed from 0 parts by weight to 100.0 parts by weight.
比較例４
実施例１における磁性塗料の組成において、Ｃｏ被着酸
化鉄磁性粉末を省き、α−Ｆｅ磁性粉末の使用量を５０
．０重量部から１００．０重量部に変更した以外は、実
施例１と同様にしてビデオテープを作成した。Comparative Example 4 In the composition of the magnetic paint in Example 1, the Co-coated iron oxide magnetic powder was omitted, and the amount of α-Fe magnetic powder used was changed to 50%.
．． A videotape was produced in the same manner as in Example 1 except that the amount was changed from 0 parts by weight to 100.0 parts by weight.
各実施例および比較例で得られたビデオテープについて
保磁力、角型、残留磁束密度、０．６ＭＨｚでの出力、
６ＭＨｚでの出力およびＣ／Ｎ比を測定した。Coercive force, square shape, residual magnetic flux density, output at 0.6 MHz, for the video tapes obtained in each example and comparative example,
The output and C/N ratio at 6 MHz were measured.
下記第１表はその結果である。Table 1 below shows the results.
第１表
〔発明の効果〕
上記第１表から明らかなように、この発明で得られたビ
デオテープ（実施例１〜３）は、いずれも比較例１ない
し４で得られたビデオテープに比し、保磁力、角型、出
力およびＣ／Ｎが高く、このことからこの発明によれば
、出力が高く、またＣ／Ｎ比が高くてノイズの低いビデ
オテープが得られ、フェライト系磁気ヘッドを用いたＶ
ＴＲに好適に使用できる電磁変換特性に優れた磁気記録
媒体が得られることがわかる。Table 1 [Effects of the Invention] As is clear from Table 1 above, the videotapes obtained by this invention (Examples 1 to 3) are all comparable to the videotapes obtained in Comparative Examples 1 to 4. However, the coercive force, square shape, output, and C/N are high. Therefore, according to the present invention, a video tape with high output, a high C/N ratio, and low noise can be obtained, and a ferrite magnetic head can be used. V using
It can be seen that a magnetic recording medium with excellent electromagnetic conversion characteristics that can be suitably used for TR can be obtained.
特許出願人 日立マクセル株式会社Patent applicant: Hitachi Maxell, Ltd.
Claims (1)
有酸化鉄磁性粉末と、金属鉄磁性粉末とを、重量比にし
て３：７〜７：３の比率で磁性層中に含有させたことを
特徴とする磁気記録媒体 ２、コバルト含有酸化鉄磁性粉末が、ＢＥＴ法による比
表面積が４０ｍ＾２／ｇ以上の酸化鉄磁性粉末の表面に
コバルトを含む磁性酸化鉄層を形成したコバルト含有酸
化鉄磁性粉末である請求項１記載の磁気記録媒体 ３、金属鉄磁性粉末が、ＢＥＴ法による比表面積が４０
ｍ＾２／ｇ以下で、飽和磁化量が１００ｅｍｕ／ｇ以上
の金属鉄磁性粉末である請求項１および２記載の磁気記
録媒体[Claims] 1. Cobalt-containing iron oxide magnetic powder having a coercive force of 700 to 900 Oe and metal iron magnetic powder are contained in a magnetic layer in a weight ratio of 3:7 to 7:3. Magnetic recording medium 2, characterized in that the cobalt-containing iron oxide magnetic powder forms a cobalt-containing magnetic iron oxide layer on the surface of the iron oxide magnetic powder having a specific surface area of 40 m^2/g or more by the BET method. The magnetic recording medium 3 according to claim 1, which is cobalt-containing iron oxide magnetic powder, wherein the metal iron magnetic powder has a specific surface area of 40 by BET method.
The magnetic recording medium according to claims 1 and 2, which is a metal iron magnetic powder having a saturation magnetization of m^2/g or less and a saturation magnetization of 100 emu/g or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15437588A JPH01320631A (en) | 1988-06-22 | 1988-06-22 | Magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15437588A JPH01320631A (en) | 1988-06-22 | 1988-06-22 | Magnetic recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01320631A true JPH01320631A (en) | 1989-12-26 |
Family
ID=15582781
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15437588A Pending JPH01320631A (en) | 1988-06-22 | 1988-06-22 | Magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01320631A (en) |
-
1988
- 1988-06-22 JP JP15437588A patent/JPH01320631A/en active Pending
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