JPH04134620A - Magnetic recording medium - Google Patents
Magnetic recording mediumInfo
- Publication number
- JPH04134620A JPH04134620A JP2253256A JP25325690A JPH04134620A JP H04134620 A JPH04134620 A JP H04134620A JP 2253256 A JP2253256 A JP 2253256A JP 25325690 A JP25325690 A JP 25325690A JP H04134620 A JPH04134620 A JP H04134620A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic recording
- magnetic
- layers
- layer
- plate
- 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
- 239000006247 magnetic powder Substances 0.000 claims abstract description 28
- 230000005415 magnetization Effects 0.000 claims abstract description 11
- 229910001567 cementite Inorganic materials 0.000 claims abstract description 7
- 229910000859 α-Fe Inorganic materials 0.000 claims description 8
- 239000000758 substrate Substances 0.000 claims description 7
- 239000011230 binding agent Substances 0.000 claims description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 3
- 229910052742 iron Inorganic materials 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 14
- AJCDFVKYMIUXCR-UHFFFAOYSA-N oxobarium;oxo(oxoferriooxy)iron Chemical compound [Ba]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O AJCDFVKYMIUXCR-UHFFFAOYSA-N 0.000 description 10
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 9
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 9
- 239000003973 paint Substances 0.000 description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 6
- 239000011248 coating agent Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 238000002834 transmittance Methods 0.000 description 5
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 229920005749 polyurethane resin Polymers 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- DVKJHBMWWAPEIU-UHFFFAOYSA-N toluene 2,4-diisocyanate Chemical compound CC1=CC=C(N=C=O)C=C1N=C=O DVKJHBMWWAPEIU-UHFFFAOYSA-N 0.000 description 3
- 229920001577 copolymer Polymers 0.000 description 2
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 description 2
- QGEOKXWFGANCJL-UHFFFAOYSA-N ethenyl acetate;hydrochloride Chemical compound Cl.CC(=O)OC=C QGEOKXWFGANCJL-UHFFFAOYSA-N 0.000 description 2
- 238000004898 kneading Methods 0.000 description 2
- 239000012046 mixed solvent Substances 0.000 description 2
- 239000004800 polyvinyl chloride Substances 0.000 description 2
- 229920000915 polyvinyl chloride Polymers 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- WRIDQFICGBMAFQ-UHFFFAOYSA-N (E)-8-Octadecenoic acid Natural products CCCCCCCCCC=CCCCCCCC(O)=O WRIDQFICGBMAFQ-UHFFFAOYSA-N 0.000 description 1
- QMMJWQMCMRUYTG-UHFFFAOYSA-N 1,2,4,5-tetrachloro-3-(trifluoromethyl)benzene Chemical compound FC(F)(F)C1=C(Cl)C(Cl)=CC(Cl)=C1Cl QMMJWQMCMRUYTG-UHFFFAOYSA-N 0.000 description 1
- LQJBNNIYVWPHFW-UHFFFAOYSA-N 20:1omega9c fatty acid Natural products CCCCCCCCCCC=CCCCCCCCC(O)=O LQJBNNIYVWPHFW-UHFFFAOYSA-N 0.000 description 1
- QSBYPNXLFMSGKH-UHFFFAOYSA-N 9-Heptadecensaeure Natural products CCCCCCCC=CCCCCCCCC(O)=O QSBYPNXLFMSGKH-UHFFFAOYSA-N 0.000 description 1
- 239000000020 Nitrocellulose Substances 0.000 description 1
- ZQPPMHVWECSIRJ-UHFFFAOYSA-N Oleic acid Natural products CCCCCCCCC=CCCCCCCCC(O)=O ZQPPMHVWECSIRJ-UHFFFAOYSA-N 0.000 description 1
- 239000005642 Oleic acid Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000003490 calendering Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- QXJSBBXBKPUZAA-UHFFFAOYSA-N isooleic acid Natural products CCCCCCCC=CCCCCCCCCC(O)=O QXJSBBXBKPUZAA-UHFFFAOYSA-N 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229920001220 nitrocellulos Polymers 0.000 description 1
- ZQPPMHVWECSIRJ-KTKRTIGZSA-N oleic acid Chemical compound CCCCCCCC\C=C/CCCCCCCC(O)=O ZQPPMHVWECSIRJ-KTKRTIGZSA-N 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- -1 polyethylene terephthalate Polymers 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- TUNFSRHWOTWDNC-HKGQFRNVSA-N tetradecanoic acid Chemical compound CCCCCCCCCCCCC[14C](O)=O TUNFSRHWOTWDNC-HKGQFRNVSA-N 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明はＶＴＲ等に用いる長尺の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 long magnetic recording medium used in VTRs and the like.
従来の技術
従来のＶＴＲ用の磁気記録媒体は記録を保持する磁気記
録層と、その磁気記録層を支持する非磁性基体と、走行
を安定化するためのバンクコート層とから構成されてい
る。その中で磁気記録層は針状酸化鉄と樹脂等と混練し
たものが多（、これらについての先行開示技術としては
、例えば特公昭６０−４７６５０号公報、特開昭６０−
１６００１８号公報、特開昭６１−１１５２３７号公報
、特開昭６３−１６６０１１号公報等がある。2. Description of the Related Art Conventional magnetic recording media for VTRs are comprised of a magnetic recording layer for retaining information, a nonmagnetic substrate for supporting the magnetic recording layer, and a bank coat layer for stabilizing running. Among them, the magnetic recording layer is often made by kneading acicular iron oxide with resin, etc. (Prior disclosed techniques for these include, for example, Japanese Patent Publication No. 60-47650, Japanese Patent Application Laid-Open No. 60-47650,
160018, JP-A-61-115237, JP-A-63-166011, etc.
−４、バンクコート層はカーボンブランクを主体とした
無機質粉末と結合剤とを混練したものである。その先行
開示技術としては、例えば特開昭６０−１６２２号公報
、特開昭６０−７６１２号公報等がある。-4. The bank coat layer is made by kneading an inorganic powder mainly composed of carbon blank and a binder. Prior art disclosures include, for example, Japanese Unexamined Patent Publications No. 1622/1982 and No. 7612/1983.
さらに、記録の高密度化、高周波特性の改善のためには
板状磁性粉を用いると効果がある。その先行開示技術と
しては、例えば特公昭６３−１３２４２号公報がある。Furthermore, it is effective to use plate-shaped magnetic powder to increase recording density and improve high frequency characteristics. As the prior art disclosed, for example, there is Japanese Patent Publication No. 63-13242.
発明が解決しようとする課題
しかしながら上記の針状酸化鉄を含有する磁性層は高周
波域における出力特性が劣り、板状磁性粉を含有する磁
性層は、遮光性が悪く電気抵抗も高いという課題を持っ
ていた。Problems to be Solved by the Invention However, the magnetic layer containing the above-mentioned acicular iron oxide has poor output characteristics in the high frequency range, and the magnetic layer containing plate-shaped magnetic powder has poor light shielding properties and high electrical resistance. had.
本発明の目的は、低周波から高周波までの広い記録帯域
において出力特性が良く、なおかつ遮光性、電気抵抗特
性も良い磁気記録媒体を提供することである。An object of the present invention is to provide a magnetic recording medium that has good output characteristics in a wide recording band from low frequencies to high frequencies, and also has good light shielding properties and electrical resistance properties.
課題を解決するための手段
上記の目的を達成するために、本発明の磁気記録媒体は
、非磁性基体の一方の面上に少なくとも２層の多層構成
の磁気記録層を設け、その磁気記録層のうち最上層の磁
気記録層は磁化容易軸を板面に垂直方向にもつ板状磁性
粉を含有し、上記最上層以外の下層の磁気記録層は針状
の炭化鉄磁性粉を含有し、かつ上記磁気記録層の磁化容
易軸を媒体の長平方向に配向させた構成を備えたもので
ある。Means for Solving the Problems In order to achieve the above-mentioned objects, the magnetic recording medium of the present invention is provided with a magnetic recording layer having a multilayer structure of at least two layers on one surface of a non-magnetic substrate. The uppermost magnetic recording layer contains plate-shaped magnetic powder with an axis of easy magnetization perpendicular to the plate surface, and the lower magnetic recording layers other than the uppermost layer contain acicular iron carbide magnetic powder, The magnetic recording layer has a structure in which the axis of easy magnetization of the magnetic recording layer is oriented in the longitudinal direction of the medium.
作用
本発明は上記した構成によって、最上層の磁気記録層に
より高周波域における出力特性と遮光性を向上し、最上
層以外の下層の磁気記録層により低周波域における出力
特性と電気抵抗特性を向上することになる。Effects With the above-described configuration, the present invention improves the output characteristics and light shielding properties in the high frequency range by the uppermost magnetic recording layer, and improves the output characteristics and electrical resistance characteristics in the low frequency range by the lower magnetic recording layer other than the uppermost layer. I will do it.
実施例 以下、本発明の一実施例について説明する。Example An embodiment of the present invention will be described below.
実施例１
最上層用の塗料として、平均粒径が０．０５μｍ、根比
が３（平均板径／平均板厚）、保磁力が８５０エルステ
ンド（○ｅ）の板状バリウムフェライト磁性粉１００重
量部に、酸化アルミニウム６重量部、カーボンプラ・２
り１重量部、ポリウレタン樹脂９重量部、ポリ塩化ビニ
ル酢酸ビニル共重合体９重量部を添加し、さらに固形分
が３０重量％となるようにメチルエチルケトン／トルエ
ン／フクロヘキサノン混合溶剤（混合比３ ： ３ ：
２）を加え、ボールミルで５時間分散の後、サントミ
ルにより２時間分散する。その後、ミリスチン酸２重量
部、ステアリン酸ブチルエステル１重量部、トリレンジ
イソシアネート系硬化剤を前記樹脂量の４．５重量％添
加し、再度混合して塗料を作る。Example 1 As a paint for the top layer, plate-shaped barium ferrite magnetic powder 100 with an average particle diameter of 0.05 μm, a root ratio of 3 (average plate diameter/average plate thickness), and a coercive force of 850 Oe Weight parts: 6 parts by weight of aluminum oxide, 2 parts by weight of carbon plastic
1 part by weight of polyurethane resin, 9 parts by weight of polyvinyl chloride vinyl acetate copolymer were added, and a mixed solvent of methyl ethyl ketone/toluene/fuclohexanone (mixing ratio 3: 3:
2) was added and dispersed in a ball mill for 5 hours, and then dispersed in a Santo mill for 2 hours. Thereafter, 2 parts by weight of myristic acid, 1 part by weight of butyl stearate, and 4.5% by weight of the tolylene diisocyanate curing agent based on the amount of the resin are added and mixed again to prepare a paint.
また、下層用の塗料として平均粒径が０．２μｍ、針状
比が８（長さ／径）、保磁力が７５００ｅの炭化鉄磁性
粉１００重量部に、オレイン酸５重量部、ポリウレタン
樹脂９重量部、ポリ塩化ビニル酢酸ビニル共重合体９重
量部を添加し、さらに固形分が３０重量％となるように
メチルエチルケトン／トルエン／シクロヘキサノン混合
溶削（混合比３：３：２）を加え、ボールミルで５時間
分散の後、サンドミルにより２時間分散する。その後、
トリレンジイソシアネート系硬化剤を前記樹脂量の４．
５重量％添加し、再度混合して磁性塗料を作る。In addition, as a paint for the lower layer, 100 parts by weight of iron carbide magnetic powder with an average particle diameter of 0.2 μm, an acicular ratio of 8 (length/diameter), and a coercive force of 7500e, 5 parts by weight of oleic acid, and 9 parts by weight of polyurethane resin were added. parts by weight, 9 parts by weight of polyvinyl chloride vinyl acetate copolymer, further added methyl ethyl ketone/toluene/cyclohexanone mixed melting (mixing ratio 3:3:2) so that the solid content was 30% by weight, and milled in a ball mill. After dispersing for 5 hours, the mixture is dispersed for 2 hours using a sand mill. after that,
Add the tolylene diisocyanate curing agent to 4.
Add 5% by weight and mix again to make a magnetic paint.
バンクコート雇用の塗料として、平均粒径が３０ｎｍの
カーボンブラ、り１００重量部に、ニトロセルロース樹
脂４０重量部、ポリウレタン樹脂４０重量部を添加し、
さらに固形分が３０重量％となるようにメチルエチルケ
トン／トルエン混合溶剤（混合比１：１）を加え、ボー
ルミルで５００時間分散る。その後、トリレンジイソシ
アネート系硬化剤を２０重量％添加し、再度混合して塗
料を作る。As a paint for Bank Coat, 40 parts by weight of nitrocellulose resin and 40 parts by weight of polyurethane resin were added to 100 parts by weight of carbon bra having an average particle size of 30 nm.
Further, a mixed solvent of methyl ethyl ketone/toluene (mixing ratio 1:1) was added so that the solid content was 30% by weight, and the mixture was dispersed in a ball mill for 500 hours. Thereafter, 20% by weight of tolylene diisocyanate curing agent is added and mixed again to form a paint.
得られた塗料を使用して非磁性基体の一方の面上に下層
磁気記録層を２．５μｍの膜厚に塗工したのち、ただち
に最上層磁気記録層を０．５μｍの膜厚に塗工した。Using the obtained paint, a lower magnetic recording layer was applied to a thickness of 2.5 μm on one side of the non-magnetic substrate, and then an uppermost magnetic recording layer was immediately applied to a thickness of 0.5 μm. did.
非磁性基体には、厚さ１１．５μｍのポリエチレンテレ
フタレートフィルムを用いた。塗工後塗膜が乾燥するま
でに、永久磁石による長手磁場配向処理を行なった。塗
膜の乾燥後、カレンダー処理（温度９０°Ｃ）を行なっ
た。その後２０時間硬化処理を行なった後、非磁性基体
の他方の面上にバンクコート層を０．５層ｍの膜厚に塗
工し、１２時間硬化処理をした後、１２．６５閣幅に裁
断して磁気記録媒体を得た。A polyethylene terephthalate film with a thickness of 11.5 μm was used as the nonmagnetic substrate. After coating and before the coating film dried, a longitudinal magnetic field orientation treatment using a permanent magnet was performed. After drying the coating film, it was calendered (temperature: 90°C). After curing for 20 hours, a bank coat layer with a thickness of 0.5 m was applied on the other side of the non-magnetic substrate, and after curing for 12 hours, the thickness was 12.65 mm. A magnetic recording medium was obtained by cutting.
最適記録電流により記録した７Ｍ）（ｚの出力を測定し
相対値で表わした。The output of 7M) (z) recorded with the optimum recording current was measured and expressed as a relative value.
オーディオ出力は市販５ＶＨＳビデオデツキにおいて最
適記録を流により記録した１ｋＨｚの出力を測定し相対
値で表わした。The audio output was measured at a 1 kHz output that was optimally recorded using a commercially available 5VHS video deck, and expressed as a relative value.
光透過率はタングステンランプを光源に用い９４０ｎｍ
の波長の光透過率を磁気記録媒体のない場合との比率を
百分率で表わした。Light transmittance is 940nm using a tungsten lamp as the light source.
The ratio of the light transmittance at the wavelength of 1 to the case without a magnetic recording medium is expressed as a percentage.
磁気記録媒体で光透過率が問題になるのは終端検知に光
を用いているためである。The reason why light transmittance is a problem in magnetic recording media is because light is used to detect the end of the media.
磁気記録層の電気抵抗は電極間路！Ｉ！５０ｍで印加電
圧５００■における抵抗値をΩ／口で表わした。The electrical resistance of the magnetic recording layer is the path between the electrodes! I! The resistance value at an applied voltage of 500 m at 50 m was expressed in Ω/mouth.
実施例２
実施例１と同様の方法で、最上層の磁気記録層に平均粒
径が０．１５μｍ、板状比が１５、保磁力が８５００ｅ
のバリウムフェライト磁性粉を含有する磁気記録媒体を
作成した。Example 2 In the same manner as in Example 1, the uppermost magnetic recording layer had an average grain size of 0.15 μm, a platelet ratio of 15, and a coercive force of 8500e.
A magnetic recording medium containing barium ferrite magnetic powder was created.
実施例３
実施例１と同様の方法で、最上層の磁気記録層に平均粒
径が０．０５μｍ、板状比が８、保磁力が１８０００ｅ
のバリウムフェライト磁性粉を含有する磁気記録媒体を
作成した。Example 3 Using the same method as in Example 1, the uppermost magnetic recording layer had an average grain size of 0.05 μm, a platelet ratio of 8, and a coercive force of 18000e.
A magnetic recording medium containing barium ferrite magnetic powder was created.
以上の実施例の構成とその特性を従来例と比較して第１
表に示す。The structure of the above embodiment and its characteristics are compared with the conventional example.
Shown in the table.
（以 下 余 白）
第１表より実施例ではオーディオ出力（低周波出力）が
低下することなくＲＦ比出力高周波出力）が大幅に向上
していることが分かる。(Margin below) Table 1 shows that in the examples, the RF specific output (high frequency output) is significantly improved without any decrease in the audio output (low frequency output).
次に磁気記録層の構成、最上層中の磁性粉の種類および
力〜ボンブランクの含を量を変えた比較例の磁気記録媒
体を作成し、その特性を測定した。Next, comparative magnetic recording media were prepared in which the configuration of the magnetic recording layer, the type of magnetic powder in the uppermost layer, and the amount of force and bomb blank content were changed, and their characteristics were measured.
比較例１
実施例１と同様の方法で、最上層の磁気記ａ層に平均粒
径が０．１８ ａｍ、 ＋Ｆｉ、状比が１８、保磁力が
９０００ｅのバリウムフェライト磁性粉を含有する磁気
記録媒体を作成した。Comparative Example 1 A magnetic recording layer containing barium ferrite magnetic powder having an average grain size of 0.18 am, +Fi, a shape ratio of 18, and a coercive force of 9000e was prepared in the same manner as in Example 1. Created media.
比較例２
実施例１と同様の方法で、最上層の磁気記録層に平均粒
径が０．０６μｍ、板状比が８、保磁力が７５００ｅの
バリウムフェライト磁性粉を含有する磁気記録媒体を作
成した。Comparative Example 2 A magnetic recording medium containing barium ferrite magnetic powder having an average grain size of 0.06 μm, a platelet ratio of 8, and a coercive force of 7500e in the uppermost magnetic recording layer was created in the same manner as in Example 1. did.
比較例３
実施例１と同様の方法で、最上層の磁気記録層に平均粒
径が０．０６μｍ、板状比が８、保磁力が２１０００ｅ
のハリウムフェライ）［性粉を含有する磁気記録媒体を
作成した。Comparative Example 3 In the same manner as in Example 1, the uppermost magnetic recording layer had an average grain size of 0.06 μm, a platelet ratio of 8, and a coercive force of 21000e.
A magnetic recording medium containing a halium ferrite powder was created.
比較例４
実施例１と同様の方法で、下層の磁気記録層を設けず、
塗布厚が２．５μｍの最上層の磁気記録層のみを設けた
磁気記録媒体を作成した。Comparative Example 4 Using the same method as Example 1, but without providing a lower magnetic recording layer,
A magnetic recording medium was prepared in which only the uppermost magnetic recording layer was provided with a coating thickness of 2.5 μm.
比較例５
実施例１と同様の方法で、最上層の磁気記録層のカーボ
ンブランク量を６重量部とし、塗布厚を２．５μｍとし
、下層の磁気記録層を設けない磁気記録媒体を作成した
。Comparative Example 5 In the same manner as in Example 1, a magnetic recording medium was created in which the amount of carbon blank in the uppermost magnetic recording layer was 6 parts by weight, the coating thickness was 2.5 μm, and the lower magnetic recording layer was not provided. .
以上の比較例の構成とその特性を第２表に示す。Table 2 shows the structure and characteristics of the above comparative example.
（以 下 余 白）
第２表から明らかなよう乙こＲＦ比出力最上層Ｓこ含有
される磁性粉の板比と保磁力Ｓこよって変化し、板状比
か１８を超えるとＲＦ比出力低下！−（比較例１と実施
例２を比較）、保磁力が２１００を超えるとＲＦ比出力
低下する（比較例３と実施例３を比較）
従って、ＲＦ比出力向上するため乙こは、最上層に含有
される板状バリウムフェライトは板比が２〜１５、保磁
力が８００−２００００ｅのものが望ましい。(Left below) As is clear from Table 2, the RF specific output changes depending on the plate ratio of the magnetic powder contained in the top layer and the coercive force S, and when the plate ratio exceeds 18, the RF specific output changes. Decrease! - (Compare Comparative Example 1 and Example 2) If the coercive force exceeds 2100, the RF specific output decreases (Compare Comparative Example 3 and Example 3) Therefore, in order to improve the RF specific output, the uppermost layer The plate-like barium ferrite contained in the steel preferably has a plate ratio of 2 to 15 and a coercive force of 800 to 20,000e.
また、板状バリウムフェライトを含有する最上層だけで
はオーディオ出力が低い、電気抵抗が高い、光透過率が
高いという問題があるが（比較例４）、下層に炭化鉄を
含有する磁気記録層を設けることによりこれらの問題が
解決できる（比較例１と比較例２を比較）。Furthermore, if only the top layer containing plate-shaped barium ferrite is used, there are problems such as low audio output, high electrical resistance, and high light transmittance (Comparative Example 4), but if the lower layer is a magnetic recording layer containing iron carbide, These problems can be solved by providing this (compare Comparative Example 1 and Comparative Example 2).
さらに、最上層に炭素の１種であるカーボンフラッフを
添加すると光透過率と電気抵抗の向上に効果がある（比
較例４と比較例５を比ｖ、）。Furthermore, adding carbon fluff, which is a type of carbon, to the top layer is effective in improving light transmittance and electrical resistance (Comparative Example 4 and Comparative Example 5 are compared).
なお、板状磁性粉の板圧が２未満の場合は板状磁性粉と
言いがたく、１５を超えると磁性粉の充填性が悪く再止
８力が充分確保できない。In addition, if the plate thickness of the plate-shaped magnetic powder is less than 2, it is difficult to say that it is plate-shaped magnetic powder, and if it exceeds 15, the filling property of the magnetic powder is poor and a sufficient retentive force cannot be ensured.
また、実施例の板状磁性粉として：よバリウムフェライ
トを使用したが、これ以外にマグヱトプランハイト型構
造を有し磁化容易軸が粒子の板面↓こ垂直方向であるヘ
キサゴナルフェライトであるカルノウムフェライト、ス
トロンチウムフェライト、釦フェライ（・またはこれら
フェライトを構成する鉄原子の一部をＣｏ、Ｔｉ、Ｚｎ
、Ｉｎ、ＣｕＧｅ、Ｎｂの群から選ばれる少なくとも一
種類の元素で置換したフェライトなどを使用しても同様
の効果が得られる。In addition, barium ferrite was used as the plate-shaped magnetic powder in the examples, but in addition to barium ferrite, barium ferrite, which is hexagonal ferrite with a maghetoplanheit structure and whose axis of easy magnetization is perpendicular to the plate surface of the particle, was also used. ferrite, strontium ferrite, button ferrite (or some of the iron atoms constituting these ferrites are Co, Ti, Zn
Similar effects can be obtained by using ferrite substituted with at least one element selected from the group consisting of , In, CuGe, and Nb.
さらに板状磁性粉の粒径は特性には影響しないが、塗膜
の厚さ、表面性、並びに塗料化時の分散性から０．０５
〜０．３μｍが好ましい。Furthermore, the particle size of the plate-shaped magnetic powder does not affect the properties, but it is 0.05
~0.3 μm is preferred.
発明の効果
以上のように本発明の磁気記録媒体によれば、磁気記録
層を少なくとも２Ｎの多Ｎ構成とし、最上層は磁化容易
軸を板面に垂直方向にもつ板状磁性粉を含有し、かつ最
上層以外の下層の磁気記録層１よ針状の炭化鉄磁性粉を
含有巳、上記磁気記録層の磁化容易軸が媒体の長手方向
りこ配されているので低周波から高周波までの広い記録
帯域において出力特性が良く、なおがっ遮光性、電気抵
抗特性も良（なるという効果が得られる。Effects of the Invention As described above, according to the magnetic recording medium of the present invention, the magnetic recording layer has a multi-N composition of at least 2N, and the uppermost layer contains plate-shaped magnetic powder having an axis of easy magnetization perpendicular to the plate surface. , and the lower magnetic recording layer 1 other than the top layer contains acicular iron carbide magnetic powder, and since the axis of easy magnetization of the magnetic recording layer is arranged in the longitudinal direction of the medium, it has a wide range of frequencies from low to high frequencies. Good output characteristics in the recording band, as well as good light shielding and electrical resistance characteristics can be obtained.
Claims (3)
散した磁気記録層を設け、上記非磁性基体の他方の面上
にバンクコート層を設けた磁気記録媒体において、磁気
記録層を少なくとも２層の多層構成とし、上記磁気記録
層のうち最上層は磁化容易軸を板面に垂直方向にもつ板
状磁性粉を含有し、上記最上層以外の下層の磁気記録層
は針状の炭化鉄磁性粉を含有し、かつ上記磁気記録層の
磁化容易軸が媒体の長手方向に配向されていることを特
徴とする磁気記録媒体。(1) A magnetic recording medium in which a magnetic recording layer in which magnetic powder is dispersed in a binder is provided on one surface of a non-magnetic substrate, and a bank coat layer is provided on the other surface of the non-magnetic substrate, in which magnetic recording is possible. The layer has a multilayer structure of at least two layers, the uppermost layer of the magnetic recording layer contains plate-shaped magnetic powder having an axis of easy magnetization perpendicular to the plate surface, and the lower magnetic recording layers other than the uppermost layer have a needle-shaped magnetic recording layer. What is claimed is: 1. A magnetic recording medium comprising iron carbide magnetic powder in the form of iron carbide, and wherein the axis of easy magnetization of the magnetic recording layer is oriented in the longitudinal direction of the medium.
磁化容易軸が板面に垂直方向であるヘキサゴナルフェラ
イトであることを特徴とする請求項１記載の磁気記録媒
体。(2) The magnetic recording medium according to claim 1, wherein the plate-shaped magnetic powder is hexagonal ferrite having a magnetoplumbite structure and an axis of easy magnetization perpendicular to the plate surface.
厚）で、保磁力が８００〜２０００エルステッド（Ｏｅ
）であることを特徴とする請求項１または２記載の磁気
記録媒体。(3) The plate ratio of the plate-shaped magnetic powder is 2 to 15 (average plate diameter/average plate thickness), and the coercive force is 800 to 2000 Oe
) The magnetic recording medium according to claim 1 or 2, wherein the magnetic recording medium is:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2253256A JPH04134620A (en) | 1990-09-21 | 1990-09-21 | Magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2253256A JPH04134620A (en) | 1990-09-21 | 1990-09-21 | Magnetic recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04134620A true JPH04134620A (en) | 1992-05-08 |
Family
ID=17248745
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2253256A Pending JPH04134620A (en) | 1990-09-21 | 1990-09-21 | Magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04134620A (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57195329A (en) * | 1981-05-26 | 1982-12-01 | Fuji Photo Film Co Ltd | Magnetic recording medium |
| JPH01128228A (en) * | 1987-11-12 | 1989-05-19 | Toshiba Corp | Magnetic recording medium |
-
1990
- 1990-09-21 JP JP2253256A patent/JPH04134620A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57195329A (en) * | 1981-05-26 | 1982-12-01 | Fuji Photo Film Co Ltd | Magnetic recording medium |
| JPH01128228A (en) * | 1987-11-12 | 1989-05-19 | Toshiba Corp | Magnetic recording medium |
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