JPH08102035A - Magnetic recording medium, its production and device therefor - Google Patents
Magnetic recording medium, its production and device thereforInfo
- Publication number
- JPH08102035A JPH08102035A JP6235592A JP23559294A JPH08102035A JP H08102035 A JPH08102035 A JP H08102035A JP 6235592 A JP6235592 A JP 6235592A JP 23559294 A JP23559294 A JP 23559294A JP H08102035 A JPH08102035 A JP H08102035A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- base material
- iron powder
- hexagonal plate
- recording medium
- 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
Landscapes
- Magnetic Record Carriers (AREA)
- Manufacturing Of Magnetic Record Carriers (AREA)
- Paints Or Removers (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は磁気記録媒体に関し、更
に詳しくは特に磁束密度が高く、短波長の記録に有利な
塗布型の磁気記録媒体に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium, and more particularly to a coating type magnetic recording medium having a high magnetic flux density and advantageous for recording at a short wavelength.
【0002】[0002]
【従来の技術】塗布型の磁気記録媒体は、磁性粉末を結
合剤と有機溶剤に分散してなる磁性塗料をポリエステル
等の基材上に塗布、乾燥して得られるものであるが、今
日、高画質ビデオテープ、大容量フロッピーディスク等
の更なる高密度記録に対する要求が高まっている。2. Description of the Related Art A coating type magnetic recording medium is obtained by coating a magnetic coating material obtained by dispersing magnetic powder in a binder and an organic solvent on a substrate such as polyester and drying it. There is an increasing demand for higher density recording such as high quality video tapes and large capacity floppy disks.
【0003】この目的を達成する磁性粉末としては、鉄
を主体とする強磁性金属粉末が最も多く用いられてい
る。鉄を主体とする強磁性金属粉末は飽和磁化、保磁力
が高く、出力特性に優れる。しかし、化学的に不安定で
錆びやすい(酸化しやすい)ため、酸化により飽和磁化
が低下し、また、ノイズ特性も必ずしも充分でなく、一
般に酸化物系磁性粉末と比べノイズレベルが高い。ま
た、鉄を主体とする強磁性金属粉末はコストが高く実用
面ではいくつかの欠点がある。Ferromagnetic metal powders composed mainly of iron are most often used as magnetic powders for achieving this purpose. Ferromagnetic metal powder composed mainly of iron has high saturation magnetization and coercive force, and has excellent output characteristics. However, since it is chemically unstable and easily rusts (is easily oxidized), the saturation magnetization is lowered by oxidation, and the noise characteristic is not always sufficient, and generally the noise level is higher than that of the oxide magnetic powder. Further, the ferromagnetic metal powder mainly composed of iron has a high cost and has some drawbacks in practical use.
【0004】また、高密度記録を実現するための方式と
して、垂直磁気記録方式が提案されており、特にこの方
式に適した磁性粉末として六角板状のバリウムフェライ
トが使用されている。しかしながら、バリウムフェライ
トは飽和磁化が低いため、磁気テープや磁気ディスクと
した場合、残留磁束密度が低くなり、低域での出力が不
足する。A perpendicular magnetic recording method has been proposed as a method for realizing high-density recording, and hexagonal plate-shaped barium ferrite is used as a magnetic powder particularly suitable for this method. However, since barium ferrite has a low saturation magnetization, when used as a magnetic tape or a magnetic disk, the residual magnetic flux density becomes low and the output in the low range becomes insufficient.
【0005】[0005]
【発明が解決しようとする課題】今後更に高密度記録化
を進めるためには、垂直磁気記録方式が有利であると考
えられるが、上記のように、六角板状バリウムフェライ
トでは残留磁束密度が低くなるため充分満足のいく磁気
記録媒体は得られない。Although it is considered that the perpendicular magnetic recording method is advantageous in order to further increase the recording density in the future, as described above, the hexagonal plate barium ferrite has a low residual magnetic flux density. Therefore, a sufficiently satisfactory magnetic recording medium cannot be obtained.
【0006】従って、本発明の目的は高密度記録を達成
する共に磁束密度が向上された塗布型の磁気記録媒体を
提供することである。Accordingly, it is an object of the present invention to provide a coating type magnetic recording medium which achieves high density recording and has an improved magnetic flux density.
【0007】[0007]
【課題を解決するための手段】本発明者は鋭意研究した
結果、磁性材料として六角板状鉄粉末を用い、且つ基材
表面に対して垂直方向に配向させることにより、上記目
的を達成し得る磁気記録媒体が得られることを見出し、
本発明を完成するに至った。Means for Solving the Problems As a result of earnest research by the present inventor, the above object can be achieved by using hexagonal plate-shaped iron powder as a magnetic material and orienting it in a direction perpendicular to the substrate surface. Finding that a magnetic recording medium can be obtained,
The present invention has been completed.
【0008】すなわち本発明は、基材と、該基材表面上
に形成された六角板状鉄粉末と結合剤とからなる磁性層
を有する磁気記録媒体において、前記六角板状鉄粉末が
前記基材の長手方向に対して垂直方向に配向されている
ことを特徴とする磁気記録媒体、及び当該磁気記録媒体
を製造する装置並びに方法を提供するものである。That is, the present invention provides a magnetic recording medium having a base material and a magnetic layer comprising a hexagonal plate-shaped iron powder formed on the surface of the base material and a binder. (EN) Provided are a magnetic recording medium characterized by being oriented in a direction perpendicular to the longitudinal direction of a material, and an apparatus and method for manufacturing the magnetic recording medium.
【0009】(I)本発明の磁気記録媒体 〔磁性層〕本発明の磁気記録媒体の磁性層について説明
する。本発明の磁気記録媒体の磁性層には六角板状鉄粉
末が使用される。かかる六角板状鉄粉末は例えば以下の
ような方法により製造される。(I) Magnetic Recording Medium of the Present Invention [Magnetic Layer] The magnetic layer of the magnetic recording medium of the present invention will be described. Hexagonal plate-shaped iron powder is used for the magnetic layer of the magnetic recording medium of the present invention. Such hexagonal plate-shaped iron powder is produced, for example, by the following method.
【0010】<六角板状鉄粉末の製造法>硫酸第一鉄水
溶液を攪拌し、これに当量以上の水酸化ナトリウムを加
え、アルカリ性にする。これにより水酸化鉄が沈澱す
る。この沈澱物を含んだ当該溶液に、攪拌下少量ずつ過
酸化水素を加える。過酸化水素を水酸化鉄に加えると、
急激に酸化されて、六角板状のδ−FeOOH が生じる。<Method for producing hexagonal plate-shaped iron powder> An aqueous ferrous sulfate solution is stirred, and an equivalent amount or more of sodium hydroxide is added thereto to make it alkaline. This causes iron hydroxide to precipitate. Hydrogen peroxide is added to the solution containing the precipitate little by little with stirring. When hydrogen peroxide is added to iron hydroxide,
It is rapidly oxidized to form hexagonal plate-shaped δ-FeOOH.
【0011】次いで水ガラスと塩化アルミニウムを加
え、酢酸等を用いてpHを4〜6に調節する。次いでろ過
し残渣を水洗し、水洗後650 ℃で空気中で焼成する。次
に420℃で水素ガスで還元し、室温まで冷却して、六角
板状鉄粉末が得られる。Next, water glass and aluminum chloride are added, and the pH is adjusted to 4 to 6 using acetic acid or the like. Then, it is filtered, the residue is washed with water, and then baked in air at 650 ° C. Next, it is reduced with hydrogen gas at 420 ° C. and cooled to room temperature to obtain hexagonal plate-shaped iron powder.
【0012】ここで、還元、冷却後、少量の空気や酸素
を通気し、表面を酸化させることが好ましい。[0012] Here, it is preferable that after the reduction and cooling, a small amount of air or oxygen is aerated to oxidize the surface.
【0013】また、六角板状鉄粉末にはCo以外にも、M
n, Cr, Ni, Zn, Sn等を微量添加してもよい。Hexagonal plate-shaped iron powder contains M in addition to Co.
A small amount of n, Cr, Ni, Zn, Sn, etc. may be added.
【0014】本発明に用いられる六角板状鉄粉末の保磁
力は限定されないが、例えば、800〜1900(Oe)程度が一
般的である。The coercive force of the hexagonal plate-shaped iron powder used in the present invention is not limited, but is generally about 800 to 1900 (Oe).
【0015】また、本発明に用いられる六角板状鉄粉末
の対角線長や板状比も特に限定されないが、対角線長0.
03〜0.5 μm 程度、また板状比は3〜20程度である。The hexagonal plate-shaped iron powder used in the present invention is not particularly limited in the diagonal length or plate ratio, but the diagonal length of 0.
It is about 03-0.5 μm and the plate ratio is about 3-20.
【0016】磁性層は、上記のようなコバルト被着酸化
鉄粉末と金属粉末と結合剤を主成分とする磁性塗料を、
基材上に塗布して形成されるが、磁性層の厚さは0.1〜
3μmが好ましい。The magnetic layer is composed of the above-mentioned magnetic coating mainly composed of cobalt-coated iron oxide powder, metal powder and binder.
It is formed by coating on the base material, but the thickness of the magnetic layer is 0.1 ~
3 μm is preferred.
【0017】上記のような六角板状の鉄粉末は面内磁化
されるため、針状のメタル粉末とは異なり、らせん走査
する磁気ヘッドであってもヘッドの走査方向に磁化され
る。また、針状メタル粉末の長軸長と六角板状鉄粉末の
対角線長が同じでも、粒子の体積は六角板状鉄粉末の方
が大きいので、高い飽和磁化量が得られる。更に単位体
積当りの有効磁性粉末数は六角板状鉄粉末を充填した方
が多くなるため、高いS/N が得られる。Since the hexagonal plate-like iron powder as described above is in-plane magnetized, unlike a needle-shaped metal powder, even a magnetic head for spiral scanning is magnetized in the scanning direction of the head. Further, even if the major axis length of the acicular metal powder and the diagonal length of the hexagonal plate-shaped iron powder are the same, since the volume of the hexagonal plate-shaped iron powder is larger, a higher saturation magnetization amount can be obtained. Furthermore, the number of effective magnetic powders per unit volume is greater when the hexagonal plate-shaped iron powder is filled, so a high S / N is obtained.
【0018】本発明の磁気記録媒体は、磁性層中の六角
板状鉄粉末が基材表面に対して垂直方向に配向されてい
ることを特徴とする。その様子を図1に示す。図1中、
1は六角板状鉄粉末、2は磁性塗料に配合される無機滑
剤、3は磁性層、4は基材、5はバックコート層であ
る。The magnetic recording medium of the present invention is characterized in that the hexagonal plate-shaped iron powder in the magnetic layer is oriented in the direction perpendicular to the surface of the base material. The situation is shown in FIG. In Figure 1,
Reference numeral 1 is hexagonal plate-shaped iron powder, 2 is an inorganic lubricant blended in a magnetic paint, 3 is a magnetic layer, 4 is a base material, and 5 is a back coat layer.
【0019】本発明の磁気記録媒体において、六角板状
鉄粉末は図1のような位置で配向されており、その結
果、垂直磁気記録方式と長手磁気記録方式の両者の長所
を具備した磁気記録媒体となる。In the magnetic recording medium of the present invention, the hexagonal plate-shaped iron powder is oriented at the position shown in FIG. 1, and as a result, magnetic recording having the advantages of both the perpendicular magnetic recording system and the longitudinal magnetic recording system. It becomes a medium.
【0020】〔結合剤〕本発明に使用される結合剤とし
ては、ウレタン樹脂、特にスルホン酸基、スルホン酸金
属塩基、スルホベタイン基、カルボベタイン基、アミノ
基、水酸基、エポキシ基等の極性基を含有するポリウレ
タン樹脂、塩化ビニル−酢酸ビニル共重合体、塩化ビニ
ル−塩化ビニリデン共重合体、塩化ビニル−アクリロニ
トリル共重合体等の塩化ビニル系共重合体であって、特
にスルホン酸基、スルホン酸金属塩基、アミノ基等の極
性基を含有する塩化ビニル共重合体、ブタジエン−アク
リロニトリル共重合体、ポリアミド樹脂、ポリビニルブ
チラール、セルロース誘導体(セルロースアセテートブ
チレート、セルロースプロピオネート、ニトロセルロー
ス等)、スチレン−ブタジエン共重合体、ポリエステル
樹脂、各種の合成ゴム系、フェノール樹脂、エポキシ樹
脂、尿素樹脂、メラミン樹脂、フェノキシ樹脂、シリコ
ン樹脂、アクリル系反応樹脂、高分子量ポリエステル樹
脂とイソシアネートプレポリマーの混合物、ポリエステ
ルポリオールとポリイソシアネートの混合物、尿素ホル
ムアルデヒド樹脂、低分子量グリコール/高分子量ジオ
ール/イソシアネートの混合物、及びこれらの混合物等
が例示され、磁性層及び中間層ともに同様のものが使用
できる。通常、結合剤は磁性塗料中に10〜30重量%程度
配合される。[Binder] The binder used in the present invention is a urethane resin, particularly a polar group such as a sulfonic acid group, a metal sulfonate group, a sulfobetaine group, a carbobetaine group, an amino group, a hydroxyl group, an epoxy group. A vinyl chloride copolymer such as a polyurethane resin containing vinyl chloride, a vinyl chloride-vinyl acetate copolymer, a vinyl chloride-vinylidene chloride copolymer, a vinyl chloride-acrylonitrile copolymer, particularly a sulfonic acid group or a sulfonic acid group. Vinyl chloride copolymers containing polar groups such as metal bases and amino groups, butadiene-acrylonitrile copolymers, polyamide resins, polyvinyl butyral, cellulose derivatives (cellulose acetate butyrate, cellulose propionate, nitrocellulose, etc.), styrene -Butadiene copolymer, polyester resin, various synthesis System, phenol resin, epoxy resin, urea resin, melamine resin, phenoxy resin, silicon resin, acrylic reaction resin, mixture of high molecular weight polyester resin and isocyanate prepolymer, mixture of polyester polyol and polyisocyanate, urea formaldehyde resin, low Examples include a mixture of molecular weight glycol / high molecular weight diol / isocyanate, and a mixture thereof, and the same materials can be used for the magnetic layer and the intermediate layer. Usually, the binder is mixed in the magnetic paint in an amount of about 10 to 30% by weight.
【0021】〔有機溶媒〕磁性塗料を構成する有機溶媒
としては、シクロヘキサノン、メチルエチルケトン、メ
チルイソブチルケトン、酢酸エチル、酢酸ブチル、ベン
ゼン、トルエン、キシレン、ジメチルスルホキシド、テ
トラヒドロフラン、ジオキサン等、使用する結合剤樹脂
を溶解するのに適した溶剤が特に制限されることなく単
独又は二種以上混合して使用される。通常、有機溶媒は
磁性塗料中に20〜80重量%程度配合される。[Organic Solvent] As the organic solvent constituting the magnetic coating material, cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, benzene, toluene, xylene, dimethyl sulfoxide, tetrahydrofuran, dioxane, etc. are used as binder resins. Solvents suitable for dissolving are not particularly limited and may be used alone or in combination of two or more. Usually, the organic solvent is mixed in the magnetic coating material in an amount of about 20 to 80% by weight.
【0022】なお、磁性塗料中には、通常使用されてい
る各種添加剤、例えば分散剤、研磨剤、潤滑剤などを適
宜に添加使用してもよい。分散剤としては、レシチン、
ノニオン系界面活性剤、アニオン系界面活性剤、カチオ
ン系界面活性剤等が使用できる。研磨剤としては、α−
アルミナ、溶融アルミナ、酸化クロム(Cr2O3) 、酸化
鉄、炭化ケイ素、コランダム、ダイヤモンド等の平均粒
子径0.05〜1μm の微粉末が使用でき、通常前記したよ
うな結合剤100 重量部に対し0.5 〜100 重量部加えられ
る。また、潤滑剤としては、各種のポリシロキサン等の
シリコーンオイル、グラファイト、二硫化モリブデン等
の無機粉末、ポリエチレン、ポリテトラフルオロエチレ
ン等のプラスチック微粉末、高級脂肪酸、高級アルコー
ル、高級脂肪酸エステル、フルオロカーボン類などが前
述した結合剤100 重量部に対して0.1 〜50重量部の割合
で添加される。In the magnetic coating composition, various commonly used additives such as dispersants, abrasives and lubricants may be appropriately added and used. As the dispersant, lecithin,
Nonionic surfactants, anionic surfactants, cationic surfactants and the like can be used. As an abrasive, α-
Fine powders having an average particle size of 0.05 to 1 μm, such as alumina, fused alumina, chromium oxide (Cr 2 O 3 ), iron oxide, silicon carbide, corundum, and diamond can be used, and usually 100 parts by weight of the binder as described above are used. 0.5 to 100 parts by weight is added. Examples of lubricants include silicone oils such as various polysiloxanes, graphite, inorganic powders such as molybdenum disulfide, fine plastic powders such as polyethylene and polytetrafluoroethylene, higher fatty acids, higher alcohols, higher fatty acid esters, and fluorocarbons. And the like are added in a ratio of 0.1 to 50 parts by weight with respect to 100 parts by weight of the binder.
【0023】本発明の磁気記録媒体に用いられる基材と
しては、合成樹脂(例えばポリエチレンテレフタレー
ト、ポリエチレンナフタレート等のポリエステル、ポリ
アミド、ポリオレフィン、セルロース系誘導体)、非磁
性の金属、ガラス、セラミック、紙等が挙げられ、その
形態は、フィルム、テープ、シート、カード、ディスク
等で使用される。The substrate used in the magnetic recording medium of the present invention includes synthetic resins (for example, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyamides, polyolefins, cellulose derivatives), non-magnetic metals, glass, ceramics and papers. Etc., and the form thereof is used in films, tapes, sheets, cards, disks and the like.
【0024】(II)本発明の製造方法 また、本発明は、基材に、六角板状鉄粉末と結合剤とを
含有する磁性塗料を塗布し、次いで基材を、基材の表面
に対して垂直方向をなす磁界中を通過させることによ
り、基材に塗布された磁性塗料中の六角板状鉄粉末を基
材表面に対して垂直方向に配向させることを特徴とする
磁気記録媒体の製造方法を提供するものである。この方
法に用いられる六角板状鉄粉末、結合剤、磁性塗料、基
材等は前記の磁気記録媒体で述べたものである。(II) Production Method of the Present Invention Further, in the present invention, a magnetic coating material containing hexagonal plate-shaped iron powder and a binder is applied to a base material, and then the base material is applied to the surface of the base material. Of hexagonal plate-shaped iron powder in the magnetic paint applied to the base material in a direction perpendicular to the surface of the base material by passing it through a magnetic field perpendicular to the base material. It provides a method. The hexagonal plate-like iron powder, binder, magnetic paint, base material and the like used in this method are as described above for the magnetic recording medium.
【0025】本発明において、六角板状鉄粉末を含有す
る磁性塗料の塗布方法は、特に限定されず、ダイ塗工、
グラビアロール塗工等、通常の塗布型の磁気記録媒体の
製造方法に準ずる。In the present invention, the method of applying the magnetic coating material containing the hexagonal plate-shaped iron powder is not particularly limited, and it may be die coating,
This is based on the usual method for producing a magnetic recording medium of coating type such as gravure roll coating.
【0026】磁性塗料を基材に塗布した後、外部磁界に
より六角板状鉄粉末を配向させるが、本発明では基材の
表面に対して垂直方向をなす磁界中を通過させ、六角板
状鉄粉末を基材表面に対して垂直方向に配向させる。図
2はそのイメージを示す略図である。図2中、21a,21
bは配向磁石であり、N極とS極が基材表面に対して垂
直に配置されている。その間を基材22を通過させること
により六角板状鉄粉末23が基材表面に対して垂直方向に
配向される。After the magnetic paint is applied to the base material, the hexagonal plate-shaped iron powder is oriented by an external magnetic field. In the present invention, the hexagonal plate-shaped iron powder is passed through a magnetic field perpendicular to the surface of the base material. The powder is oriented perpendicular to the substrate surface. FIG. 2 is a schematic diagram showing the image. In FIG. 2, 21a, 21
Reference numeral b is an oriented magnet, in which the N pole and the S pole are arranged perpendicularly to the surface of the base material. By passing the base material 22 between them, the hexagonal plate-shaped iron powder 23 is oriented in the direction perpendicular to the surface of the base material.
【0027】本発明により形成される磁性層の厚さは、
0.05〜9μm 、好ましくは 0.1〜5μm である。The thickness of the magnetic layer formed by the present invention is
The thickness is 0.05 to 9 μm, preferably 0.1 to 5 μm.
【0028】本発明の製造方法において、磁性層を塗布
した後配向する工程以外の工程は、通常の塗布型の製造
方法に準じて、乾燥、表面処理、キュア、裁断、検査、
カセット組み込み等の工程を行えばよい。In the manufacturing method of the present invention, the steps other than the step of orienting after coating the magnetic layer are carried out in accordance with the usual coating type manufacturing method, such as drying, surface treatment, curing, cutting, inspection,
A process such as assembling a cassette may be performed.
【0029】(III) 本発明の製造装置 本発明は、また、基材の搬送手段と、基材の搬送径路に
沿って、基材上に六角板状鉄粉末を含有する磁性塗料を
塗布する手段と、基材に塗布された磁性塗料中の六角板
状鉄粉末を配向する手段と、基材に塗布された磁性塗料
を乾燥する手段とがこの順で配設されている磁気記録媒
体の製造装置において、前記六角板状鉄粉末を配向する
手段が、基材表面に対して垂直方向に磁界を生じせしめ
ること特徴とする磁気記録媒体の製造装置を提供するも
のである。(III) Manufacturing Apparatus of the Present Invention The present invention also applies a magnetic coating material containing hexagonal plate-shaped iron powder onto the base material along the base material transfer means and the transfer path of the base material. A magnetic recording medium in which the means, the means for orienting the hexagonal plate-shaped iron powder in the magnetic coating material applied to the base material, and the means for drying the magnetic coating material applied to the base material are arranged in this order. In the manufacturing apparatus, the means for orienting the hexagonal plate-shaped iron powder causes a magnetic field to be generated in a direction perpendicular to the surface of the base material.
【0030】本発明の製造装置における基材の搬送手段
は送りローラー、巻き出しロール、巻取りロール等であ
り、これらは公知の製造装置のものが適用できる。ま
た、磁性塗料の塗布手段もグラビアロールコーター、ナ
イフコーター、リバースロールコーター等公知の製造装
置のものが適用できる。更に磁性塗料の乾燥手段も公知
の製造装置のものが適用できる。The substrate conveying means in the manufacturing apparatus of the present invention is a feed roller, an unwinding roll, a winding roll, etc., and those known in the manufacturing apparatus can be applied. Further, the magnetic coating material may be applied by a known manufacturing apparatus such as a gravure roll coater, a knife coater, a reverse roll coater. Further, as a drying means for the magnetic paint, a known manufacturing apparatus can be applied.
【0031】本発明の製造装置は、六角板状鉄粉末を含
有する磁性塗料を用いた磁気記録媒体の製造に用いら
れ、その特徴とするところは、六角板状鉄粉末を配向す
る手段が、基材表面に対して垂直方向に磁界を生じせし
めることである。The manufacturing apparatus of the present invention is used for manufacturing a magnetic recording medium using a magnetic coating material containing hexagonal plate-shaped iron powder, and is characterized by a means for orienting the hexagonal plate-shaped iron powder. This is to generate a magnetic field in the direction perpendicular to the surface of the base material.
【0032】図3は、本発明の製造装置の一例を示す略
図である。図3中、30はチャンバであり、31a,31b は配
向磁石、32は巻き出しロール、33は静電除塵機、34はグ
ラビアロールコーター、35はスムーザー、36は第一乾燥
室、37は第二乾燥室、38は第三乾燥室、39は巻取りロー
ル、40は基材、41はドライヤーである。FIG. 3 is a schematic view showing an example of the manufacturing apparatus of the present invention. In FIG. 3, 30 is a chamber, 31a and 31b are oriented magnets, 32 is an unwinding roll, 33 is an electrostatic dust remover, 34 is a gravure roll coater, 35 is a smoother, 36 is a first drying chamber, and 37 is a first drying chamber. Two drying chambers, 38 is a third drying chamber, 39 is a winding roll, 40 is a base material, and 41 is a dryer.
【0033】基材40は巻き出しロール32から静電除塵機
33を経てグラビアロールコーター34に搬送され、グラビ
アロールコーター34により六角板状鉄粉末を含有する磁
性塗料Aが塗布される。その後、基材40はスムーザーを
通過し、基材に塗布された磁性塗料が充分流動性のある
状態で配向磁石31a,31b の間を通過する。配向磁石は基
材表面に対して垂直方向に磁界を生じるよう、図2のよ
うに配置されており、これにより図1に示したような状
態で六角板状鉄粉末が配向される。配向を終えた基材は
先ずドライヤー41で予備的に乾燥され、第一乾燥室36、
第二乾燥室37、第三乾燥室38を通過し、乾燥を完了した
後巻取りロール39で巻き取られる。The base material 40 is removed from the unwinding roll 32 by an electrostatic dust remover.
It is conveyed to the gravure roll coater 34 via 33, and the magnetic coating material A containing the hexagonal plate-shaped iron powder is applied by the gravure roll coater 34. After that, the base material 40 passes through the smoother, and the magnetic coating material applied to the base material passes between the orientation magnets 31a and 31b in a sufficiently fluid state. The orienting magnet is arranged as shown in FIG. 2 so as to generate a magnetic field in the direction perpendicular to the surface of the base material, whereby the hexagonal plate-shaped iron powder is oriented in the state as shown in FIG. The oriented base material is first preliminarily dried by the dryer 41, the first drying chamber 36,
After passing through the second drying chamber 37 and the third drying chamber 38 to complete the drying, the film is taken up by the take-up roll 39.
【0034】本発明の製造装置において、配向磁石は永
久磁石でも電磁石でもよく、その他の磁界を生じせしめ
る手段も適用できるが、磁界が基材表面に対して垂直方
向をなすように配置されることが必要である。In the manufacturing apparatus of the present invention, the oriented magnet may be a permanent magnet or an electromagnet, and other means for generating a magnetic field can be applied, but the magnetic field is arranged so as to be perpendicular to the substrate surface. is necessary.
【0035】[0035]
【発明の効果】本発明によれば、耐久性が良好で、且つ
高密度記録が可能で、特に磁束密度が高く、且つ短波長
の記録に有利な磁気記録媒体が得られる。According to the present invention, it is possible to obtain a magnetic recording medium which has good durability and enables high density recording, has a particularly high magnetic flux density, and is advantageous for recording at a short wavelength.
【0036】[0036]
【実施例】以下実施例にて本発明を更に説明するが、本
発明はこれらの実施例に限定されるものではない。The present invention will be further described in the following examples, but the present invention is not limited to these examples.
【0037】製造例1 5%硫酸第一鉄水溶液を羽根付き攪拌反応槽に入れる。
次いで10%水酸化ナトリウム水溶液を少量ずつ添加し、
pHを10に調整する。この時、白色の水酸化鉄が沈澱す
る。次いで、溶液内の沈澱物が全て茶褐色(或いは黒み
がかった茶色)になるまで20%過酸化水素水溶液を添加
する。ここで生成する茶褐色の沈澱物は六角板状のδ−
FeOOH である。引き続きフィルタープレスを用いて水洗
及びろ過を行なった。Production Example 1 A 5% ferrous sulfate aqueous solution is placed in a stirring reaction vessel equipped with blades.
Then add 10% sodium hydroxide aqueous solution little by little,
Adjust pH to 10. At this time, white iron hydroxide precipitates. Then, 20% aqueous hydrogen peroxide solution is added until all the precipitate in the solution becomes dark brown (or dark brown). The brown-colored precipitate formed here is a hexagonal plate-like δ-
FeOOH. Subsequently, washing with water and filtration were performed using a filter press.
【0038】次いで、同じ攪拌反応槽に純水を加え、ろ
過残渣をよく分散させ、最初に仕込んだ硫酸第一鉄水溶
液の鉄に対して水ガラスを1重量%、塩化アルミニウム
を1重量%加え、酢酸を加えてpHを4に調整する。引き
続きフィルタープレスを用いて水洗及びろ過を行なっ
た。その後、沈澱物をマッフル炉を用いて空気中で650
℃で2時間焼成する。次いで450 ℃でバッチ式キルンを
用いて水素ガスで還元する。Then, pure water was added to the same stirred reaction tank to disperse the filtration residue well, and 1% by weight of water glass and 1% by weight of aluminum chloride were added to the iron in the ferrous sulfate aqueous solution initially charged. The pH is adjusted to 4 by adding acetic acid. Subsequently, washing with water and filtration were performed using a filter press. The precipitate is then 650 in air using a muffle furnace.
Bake at 2 ° C. for 2 hours. Then, it is reduced with hydrogen gas using a batch kiln at 450 ° C.
【0039】次いで反応系の温度を室温まで下げ少量の
空気を通気し、40時間かけて全てのガスを空気に置換
し、金属粉末の表面を酸化し安定させる。Next, the temperature of the reaction system is lowered to room temperature and a small amount of air is aerated, and all the gas is replaced with air for 40 hours to oxidize and stabilize the surface of the metal powder.
【0040】ここで、得られた金属粉末は、六角板状の
鉄粉末であり、板状比は1:8で、Hcは1530(Oe)、σs
は128(emu/g)であった。この六角板状鉄粉末をA粉と
し、以下の実施例1で用いた。Here, the obtained metal powder is hexagonal plate-shaped iron powder, the plate ratio is 1: 8, Hc is 1530 (Oe), σs
Was 128 (emu / g). This hexagonal plate-shaped iron powder was used as powder A and used in Example 1 below.
【0041】実施例1 (1) 磁性塗料の調製 上記で得られたA粉と、以下に示す各成分をサンドミル
にて分散し、磁性層用の磁性塗料を作製した。 <磁性塗料成分> ・A粉 24.6重量% ・塩化ビニル系樹脂 1.9重量% ・ポリウレタン系樹脂 2.8重量% ・イソシアネート 0.7重量% ・Al2O3 (粒径0.15μm ) 3.0重量% ・脂肪酸エステル 0.8重量% ・トルエン 29.8重量% ・メチルエチルケトン 29.8重量% ・シクロヘキサノン 6.6重量%。Example 1 (1) Preparation of magnetic coating A powder obtained above and the following components were dispersed in a sand mill to prepare a magnetic coating for a magnetic layer. <Magnetic paint components> ・ A powder 24.6% by weight ・ Vinyl chloride resin 1.9% by weight ・ Polyurethane resin 2.8% by weight ・ Isocyanate 0.7% by weight ・ Al 2 O 3 (particle size 0.15 μm) 3.0% by weight ・ Fatty acid ester 0.8% by weight % Toluene 29.8% by weight Methyl ethyl ketone 29.8% by weight Cyclohexanone 6.6% by weight.
【0042】(2) 磁気記録媒体の製造 図3の装置により磁性層を塗布し、磁気記録媒体を製造
した。即ち、上記の磁性塗料を、ダイレクトグラビア法
により乾燥後の厚さが2.5μmになるように厚さ10μm の
PET フィルム上に塗布する。その直後、磁性塗料が充分
流動性を有するうちに配向磁石により配向する。このと
き、磁性塗料中の六角板状鉄粉末の面内磁化容易軸(板
面)が、その磁界の方向と平行に向きを変え、磁性塗料
中で基材に対して垂直方向に配向する(図1,2)。(2) Manufacture of magnetic recording medium A magnetic recording medium was manufactured by applying a magnetic layer using the apparatus shown in FIG. That is, the above magnetic paint was coated with a direct gravure method to a thickness of 10 μm so that the thickness after drying was 2.5 μm.
Apply on PET film. Immediately thereafter, the magnetic paint is oriented by the oriented magnet while having sufficient fluidity. At this time, the in-plane easy axis of magnetization (plate surface) of the hexagonal plate-shaped iron powder in the magnetic paint changes its direction parallel to the direction of the magnetic field, and is oriented in the magnetic paint in a direction perpendicular to the substrate ( 1 and 2).
【0043】更にカーボンブラックを主成分とする塗料
を、フィルムの磁性層が形成されている面の裏面に乾燥
後の厚さが 0.5μm になるように塗布し乾燥した。Further, a coating material containing carbon black as a main component was applied to the back surface of the film on which the magnetic layer was formed so that the thickness after drying was 0.5 μm and dried.
【0044】このフィルムを8mm幅のテープ状に裁断
し、8mmカセットケースに入れて、市販のハイバンド8
mmVTR装置をノイズメーターに接続し、Y-S/N 、C-S/
N(AM、PM) を測定し (記録波長 0.7μm)、市販のレファ
レンステープ(ソニー (株) 製)と比較してdB単位で表
示した。また、8mmテープの磁気特性として、保磁力
( Hc1:長手保磁力、 Hc2:垂直保磁力)と残留磁束密
度(Br)をVSM を用いて測定した。結果を表1に示す。This film was cut into a tape having a width of 8 mm, placed in an 8 mm cassette case, and put into a commercially available high band 8
The mmVTR device is connected to the noise meter, and YS / N, CS /
N (AM, PM) was measured (recording wavelength 0.7 μm) and compared with a commercially available reference tape (manufactured by Sony Corporation), and displayed in dB. As the magnetic properties of the 8 mm tape, coercive force (Hc 1 : longitudinal coercive force, Hc 2 : perpendicular coercive force) and residual magnetic flux density (Br) were measured using VSM. The results are shown in Table 1.
【0045】製造例2 5%硫酸第一鉄水溶液を羽根付き攪拌反応槽に入れる。
次いで10%水酸化ナトリウム水溶液を少量ずつ添加し、
pHを10に調整する。この時、白色の水酸化鉄が沈澱す
る。次いで、溶液内の沈澱物が全て茶褐色(或いは黒み
がかった茶色)になるまで20%過酸化水素水溶液を添加
する。ここで生成する茶褐色の沈澱物は六角板状のδ−
FeOOH である。引き続きフィルタープレスを用いて水洗
及びろ過を行なった。Production Example 2 A 5% ferrous sulfate aqueous solution is placed in a stirring reaction vessel equipped with blades.
Then add 10% sodium hydroxide aqueous solution little by little,
Adjust pH to 10. At this time, white iron hydroxide precipitates. Then, 20% aqueous hydrogen peroxide solution is added until all the precipitate in the solution becomes dark brown (or dark brown). The brown-colored precipitate formed here is a hexagonal plate-like δ-
FeOOH. Subsequently, washing with water and filtration were performed using a filter press.
【0046】次いで、同じ攪拌反応槽に純水を加え、ろ
過残渣をよく分散させ、最初に仕込んだ硫酸第一鉄水溶
液の鉄に対して硝酸コバルトを5重量%添加した。更に
最初に仕込んだ硫酸第一鉄水溶液の鉄に対して水ガラス
を1重量%、塩化アルミニウムを1重量%加え、酢酸を
加えてpHを4に調整する。引き続きフィルタープレスを
用いて水洗及びろ過を行なった。その後、沈澱物をマッ
フル炉を用いて空気中で650 ℃で2時間焼成する。次い
で450 ℃でバッチ式キルンを用いて水素ガスで還元し、
再酸化を250 ℃で30分行った。Next, pure water was added to the same stirring reaction tank to thoroughly disperse the filtration residue, and 5% by weight of cobalt nitrate was added to the iron in the initially prepared ferrous sulfate aqueous solution. Further, 1% by weight of water glass and 1% by weight of aluminum chloride are added to iron in the ferrous sulfate aqueous solution initially charged, and acetic acid is added to adjust the pH to 4. Subsequently, washing with water and filtration were performed using a filter press. The precipitate is then calcined in air in a muffle furnace at 650 ° C for 2 hours. Then reduce with hydrogen gas using a batch kiln at 450 ℃,
Reoxidation was carried out at 250 ° C for 30 minutes.
【0047】ここで、得られた金属粉末を科学分析した
結果、Co−γ−Fe2O3 であることが判明し、またTEM で
形状を観察した結果、六角板状であることを確認した。
この粉末の保磁力は600 (Oe)、板状比は1:8で、σs
は75 (emu/g)であった。この六角板状鉄粉末をB粉と
し、以下の実施例2で用いた。Here, as a result of scientific analysis of the obtained metal powder, it was found to be Co-γ-Fe 2 O 3 , and as a result of observing the shape with TEM, it was confirmed to be a hexagonal plate shape. .
The coercive force of this powder is 600 (Oe), the plate ratio is 1: 8, and σs
Was 75 (emu / g). This hexagonal plate-shaped iron powder was designated as B powder and used in Example 2 below.
【0048】実施例2 上記製造例2で得られたB粉を実施例1のA粉の代わり
に用いて磁性塗料を調製し、実施例1と同様に8mmテー
プを作製し、同様の試験を行った。結果を表1に示す。Example 2 The powder B obtained in the above Production Example 2 was used in place of the powder A of Example 1 to prepare a magnetic coating material, an 8 mm tape was prepared in the same manner as in Example 1, and the same test was conducted. went. The results are shown in Table 1.
【0049】比較例1 実施例1の磁性塗料において、A粉に代えて、保磁力 5
90(Oe)、σs 73 (emu/g)、平均長軸長0.2 μm 、平均短
軸長0.04μm の針状Co−γ−Fe2O3 を用い、それ以外は
実施例1と同様に8mmテープを作製し、同様の試験を行
った。結果を表1に示す。Comparative Example 1 In the magnetic coating material of Example 1, coercive force 5 was used instead of powder A.
90 (Oe), σ s 73 (emu / g), average major axis length 0.2 μm, average minor axis length 0.04 μm of needle-like Co-γ-Fe 2 O 3 was used, and otherwise 8 mm as in Example 1. A tape was prepared and the same test was conducted. The results are shown in Table 1.
【0050】なお、本例により得られたテープの構成を
示す断面略示図を図4に示す。図4では針状のCo−γ−
Fe2O3 粉41は基材42の表面に対して垂直方向を向くよう
に配向されている。FIG. 4 is a schematic sectional view showing the structure of the tape obtained in this example. In Fig. 4, needle-shaped Co-γ-
The Fe 2 O 3 powder 41 is oriented so as to be oriented in a direction perpendicular to the surface of the base material 42.
【0051】比較例2 実施例1において、図3の装置の代わりに図5に示す従
来の装置(配向をソレノイド法により行う装置)を用い
る他は実施例1と同様に8mmテープを作製し、同様の試
験を行った。図5中、ソレノイド52以外は図3の装置と
同じである。なお、本例により得られたテープの構成を
示す断面略示図を図6に示す。図5では六角板状鉄粉末
61は基材62の表面と平行に配向されている。Comparative Example 2 An 8 mm tape was prepared in the same manner as in Example 1 except that the conventional device shown in FIG. 5 (device for performing the orientation by the solenoid method) was used in place of the device shown in FIG. 3 in Example 1. A similar test was conducted. 5 is the same as the device of FIG. 3 except for the solenoid 52. A schematic sectional view showing the structure of the tape obtained in this example is shown in FIG. In Fig. 5, hexagonal plate-shaped iron powder
61 is oriented parallel to the surface of the substrate 62.
【0052】[0052]
【表1】 [Table 1]
【0053】*基準:市販の8mmリファレンステープ
〔ソニー (株) 製〕* Criteria: Commercially available 8 mm reference tape (manufactured by Sony Corporation)
【図1】本発明の磁気記録媒体の構造の一例を示す略図FIG. 1 is a schematic diagram showing an example of the structure of a magnetic recording medium of the present invention.
【図2】六角板状鉄粉末の配向方法を示す略図FIG. 2 is a schematic diagram showing a method for orienting hexagonal plate-shaped iron powder.
【図3】本発明の磁気記録媒体の製造装置の一例を示す
略図FIG. 3 is a schematic view showing an example of an apparatus for manufacturing a magnetic recording medium of the present invention.
【図4】比較例1で得られた磁気記録媒体の構造を示す
略図4 is a schematic diagram showing the structure of a magnetic recording medium obtained in Comparative Example 1. FIG.
【図5】従来の磁気記録媒体の製造装置の一例を示す略
図FIG. 5 is a schematic view showing an example of a conventional magnetic recording medium manufacturing apparatus.
【図6】比較例2で得られた磁気記録媒体の構造を示す
略図6 is a schematic diagram showing the structure of a magnetic recording medium obtained in Comparative Example 2. FIG.
1 六角板状鉄粉末 4 基材 21a,21b 配向磁石 31a,31b 配向磁石 1 Hexagonal plate-shaped iron powder 4 Base material 21a, 21b Oriented magnet 31a, 31b Oriented magnet
フロントページの続き (72)発明者 若林 繁美 栃木県芳賀郡市貝町大字赤羽2606番地 花 王株式会社情報科学研究所内 (72)発明者 水野谷 博英 栃木県芳賀郡市貝町大字赤羽2606番地 花 王株式会社情報科学研究所内Front page continuation (72) Inventor Shigemi Wakabayashi 2606 Akabane, Kai-cho, Haga-gun, Tochigi Prefecture Kao Corporation Information Science Laboratory (72) Inventor Hirohide Mizunoya 2606 Akabane, Kai-cho, Haga-gun, Tochigi Prefecture Kao Corporation Information Science Laboratory
Claims (3)
板状鉄粉末と結合剤とからなる磁性層を有する磁気記録
媒体において、前記六角板状鉄粉末が前記基材表面に対
して垂直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 comprising a base material and a magnetic layer comprising a hexagonal plate-shaped iron powder formed on the surface of the base material and a binder, wherein the hexagonal plate-shaped iron powder is formed on the surface of the base material. A magnetic recording medium characterized in that it is vertically oriented.
有する磁性塗料を塗布し、次いで基材を、基材の表面に
対して垂直方向をなす磁界中を通過させることにより、
基材に塗布された磁性塗料中の六角板状鉄粉末を基材表
面に対して垂直方向に配向させることを特徴とする磁気
記録媒体の製造方法。2. A base material is coated with a magnetic coating material containing hexagonal plate-shaped iron powder and a binder, and then the base material is passed through a magnetic field perpendicular to the surface of the base material. ,
A method for producing a magnetic recording medium, characterized in that hexagonal plate-shaped iron powder in a magnetic coating material applied to a base material is oriented in a direction perpendicular to the surface of the base material.
って、基材上に六角板状鉄粉末を含有する磁性塗料を塗
布する手段と、基材に塗布された磁性塗料中の六角板状
鉄粉末を配向する手段と、基材に塗布された磁性塗料を
乾燥する手段とがこの順で配設されている磁気記録媒体
の製造装置において、 前記六角板状鉄粉末を配向する手段が、基材表面に対し
て垂直方向に磁界を生じせしめること特徴とする磁気記
録媒体の製造装置。3. A base material conveying means, a means for applying a magnetic coating material containing hexagonal plate-shaped iron powder onto the base material along a base material conveying path, and a magnetic coating material applied to the base material. In the apparatus for manufacturing a magnetic recording medium, wherein the means for orienting the hexagonal plate-shaped iron powder and the means for drying the magnetic paint applied to the base material are arranged in this order, the hexagonal plate-shaped iron powder is oriented. An apparatus for producing a magnetic recording medium, characterized in that the means for producing generate a magnetic field in a direction perpendicular to the surface of the base material.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6235592A JPH08102035A (en) | 1994-09-29 | 1994-09-29 | Magnetic recording medium, its production and device therefor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6235592A JPH08102035A (en) | 1994-09-29 | 1994-09-29 | Magnetic recording medium, its production and device therefor |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH08102035A true JPH08102035A (en) | 1996-04-16 |
Family
ID=16988290
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP6235592A Pending JPH08102035A (en) | 1994-09-29 | 1994-09-29 | Magnetic recording medium, its production and device therefor |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH08102035A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2021065018A1 (en) * | 2019-10-02 | 2021-04-08 | ソニー株式会社 | Magnetic recording medium |
JP2021061081A (en) * | 2019-10-02 | 2021-04-15 | ソニー株式会社 | Magnetic recording medium |
JP2021061080A (en) * | 2019-12-18 | 2021-04-15 | ソニー株式会社 | Magnetic recording medium |
-
1994
- 1994-09-29 JP JP6235592A patent/JPH08102035A/en active Pending
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2021065018A1 (en) * | 2019-10-02 | 2021-04-08 | ソニー株式会社 | Magnetic recording medium |
JP2021061075A (en) * | 2019-10-02 | 2021-04-15 | ソニー株式会社 | Magnetic recording medium |
JP2021061081A (en) * | 2019-10-02 | 2021-04-15 | ソニー株式会社 | Magnetic recording medium |
JP2021061080A (en) * | 2019-12-18 | 2021-04-15 | ソニー株式会社 | Magnetic recording medium |
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