JP3207875B2 - Manufacturing method of magnetic recording medium - Google Patents
Manufacturing method of magnetic recording mediumInfo
- Publication number
- JP3207875B2 JP3207875B2 JP18344591A JP18344591A JP3207875B2 JP 3207875 B2 JP3207875 B2 JP 3207875B2 JP 18344591 A JP18344591 A JP 18344591A JP 18344591 A JP18344591 A JP 18344591A JP 3207875 B2 JP3207875 B2 JP 3207875B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- support
- magnetic field
- layer
- 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.)
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- Manufacturing Of Magnetic Record Carriers (AREA)
Description
【0001】[0001]
【産業上の利用分野】本発明は磁気記録媒体の製造方法
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetic recording medium.
【0002】[0002]
【従来の技術】磁気記録媒体を製造するにあたり、その
塗布方法としてリバース方式あるいはグラビア方式が一
般に用いられている。リバース方式においては、基本的
にスムージングを用いなくてもある程度平滑な塗膜が得
られるが、塗料物性との複雑な関係により、大なり小な
り長手方向に三次元的な塗布スジが発生する。一方、グ
ラビア方式においては、グラビアパターンを転写するた
め均一で平滑な塗膜を得るためスムージングが不可欠で
ある。2. Description of the Related Art In manufacturing a magnetic recording medium, a reverse method or a gravure method is generally used as a coating method. In the reverse method, a smooth coating film can be obtained to a certain extent without using smoothing. However, a three-dimensional coating streak is generated in the longitudinal direction, more or less, due to a complicated relationship with the paint properties. On the other hand, in the gravure method, smoothing is indispensable in order to transfer a gravure pattern and to obtain a uniform and smooth coating film.
【0003】従来用いられているスムージングの方式と
しては、塗膜表面にベースフィルムあるいは金属等のス
ムージング手段を接触させ、塗料の降伏値よりも高い剪
断応力を発生させてある程度の平滑塗膜を得ている。し
かしながら、この場合も接触部の不均一さ、あるいは接
触部末端部の精度等の要因で長手筋を発生したり、プリ
ントされたグラビアパターンが残ったりといった欠点が
ある。[0003] As a conventional smoothing method, a smoothing means such as a base film or a metal is brought into contact with the surface of a coating film to generate a shear stress higher than the yield value of the coating material to obtain a smooth coating film to some extent. ing. However, in this case as well, there are disadvantages such as generation of longitudinal streaks due to unevenness of the contact portion, accuracy of the end portion of the contact portion, and a printed gravure pattern remaining.
【0004】一方、媒体の記録密度を高めるために、磁
性粉の高保磁力化、高飽和磁束密度化、微粒子化や、高
充填化、高配向化、平面平滑化、薄層化等が行われてい
る。しかし、これらの高密度化を行うと、媒体の信頼性
や耐久性が低下し、例えば磁気ヘッドの目詰まりやドロ
ップアウトが多発したり、スチル特性の低下等が生じて
しまう。これら信頼性、耐久性の向上法として、研磨材
の種類や添加量について提案がされている。On the other hand, in order to increase the recording density of a medium, high coercive force, high saturation magnetic flux density, fine particles, high filling, high orientation, planar smoothing, thinning of the magnetic powder, etc. are performed. ing. However, when the density is increased, the reliability and durability of the medium are reduced, and for example, clogging and dropout of the magnetic head frequently occur, and still characteristics are deteriorated. As a method for improving the reliability and durability, proposals have been made on the type and amount of abrasive added.
【0005】研磨材の添加量についていえば、例えば特
開昭61−57036号公報では、研磨材の磁性層表面
上の密度を0.25個/μm 2 以上に規制する旨の提案
がなされている。しかし、4μm 程度以下の薄層化した
高密度記録用の磁性層の場合には、通常の添加方法にて
このように研磨材を増量すると、信頼性や耐久性は向上
するが、感度やC/N等の電磁変換特性が低下したり、
磁気ヘッドの摩耗量が増大してしまう。Concerning the amount of abrasive added, for example, Japanese Patent Application Laid-Open No. 61-57036 proposes that the density of the abrasive on the surface of the magnetic layer be regulated to 0.25 particles / μm 2 or more. I have. However, in the case of a thin magnetic layer for high-density recording having a thickness of about 4 μm or less, if the amount of abrasive is increased by the usual addition method, reliability and durability are improved, but sensitivity and C / N etc. deteriorates,
The wear amount of the magnetic head increases.
【0006】一方、特公昭54−14482号公報に
は、磁性層を2層積層して、下側磁性層の研磨材量を、
表面磁性層の研磨材量の1/3以下とし、ヘッド目詰ま
り防止効果と、電磁変換特性とを向上する旨が提案され
ている。しかし、この公報では、その実施例から明らか
なように、6μm と4μm の2層の磁性層を積層して1
0μm の磁性層としており、高密度化および記録の長時
間化の際に要求される例えば4μm 以下の磁性層につい
ては念頭におかれていない。すなわち、このような薄層
化した磁性層では、この公報のように重層積層するのは
難しく、生産性がきわめて悪い。また、上層を0.6μ
m程度にまで薄層化して積層できたとしても、上層中の
研磨材の含有密度は厚み方向に亘って均一であり、層中
で高い密度を維持しており、また、上層厚さ自体が薄す
ぎて、カレンダー処理での加工が不十分となる。このた
め、特に電磁変換特性に対する悪影響が大きく、しかも
複雑な製造プロセスによる稼動率の低下となる。On the other hand, Japanese Patent Publication No. 54-14482 discloses that two magnetic layers are laminated, and the abrasive amount of the lower magnetic layer is reduced.
It has been proposed to reduce the amount of the abrasive in the surface magnetic layer to 1/3 or less to improve the head clogging prevention effect and the electromagnetic conversion characteristics. However, in this gazette, as is apparent from the examples, two magnetic layers of 6 μm and 4 μm are laminated to form one layer.
The magnetic layer has a thickness of 0 μm, and a magnetic layer of, for example, 4 μm or less, which is required for high density and long recording, is not considered. That is, it is difficult to form such a thin magnetic layer in a multi-layer structure as described in this publication, and the productivity is extremely poor. The upper layer is 0.6μ
Even if it can be laminated to a thickness of about m, the density of the abrasive in the upper layer is uniform in the thickness direction, maintains a high density in the layer, and the thickness of the upper layer itself is It is too thin, and the processing in the calendar process becomes insufficient. For this reason, the adverse effect on the electromagnetic conversion characteristics is particularly large, and the operation rate is reduced due to a complicated manufacturing process.
【0007】このように、高密度媒体においては、電磁
変換特性の向上と、媒体の信頼性や耐久性の向上とは相
反する面があり、従来の研磨材の添加法ではこれらを両
立させることはきわめて困難である。As described above, in a high-density medium, there is a contradiction between the improvement of the electromagnetic conversion characteristics and the improvement of the reliability and durability of the medium. Is extremely difficult.
【0008】[0008]
【発明が解決しようとする課題】本発明の第1の目的
は、グラビアパターンや長手スジ等の塗布欠陥を減少し
た磁気記録媒体の製造方法を提供することにある。本発
明の他の目的は、高密度記録に適した媒体であって、特
に単層の磁性層を有し、高い電磁変換特性を示し、しか
も高い信頼性や耐久性を示す磁気記録媒体の製造方法を
提供することにある。SUMMARY OF THE INVENTION It is a first object of the present invention to provide a method of manufacturing a magnetic recording medium having reduced coating defects such as gravure patterns and longitudinal stripes. Another object of the present invention is to manufacture a medium suitable for high-density recording, particularly having a single magnetic layer, exhibiting high electromagnetic conversion characteristics, and exhibiting high reliability and durability. It is to provide a method.
【0009】[0009]
【課題を解決するための手段】このような目的は下記の
(1)〜(7)の本発明によって達成される。 (1) 長尺の非磁性支持体を連続的に移動させなが
ら、磁性粉とバインダとを含有する磁性層用塗布組成物
をグラビア塗布した後、前記非磁性支持体の一面側に、
非磁性支持体の移動方向に対して傾斜しているグラビア
パターンと磁界成分が一致しないよう単位磁石を非磁性
支持体の移動方向と傾斜するように複数配置し、この単
位磁石は前記非磁性支持体の一面側に一方の磁極のみが
位置しており、相隣接する磁極が互いに異なり、前記単
位磁石の長さ方向が、前記非磁性支持体と平行でその長
手方向と傾斜するように、前記非磁性支持体に対向して
配置し、前記非磁性支持体の移動方向と傾斜した前記単
位磁石間の磁界を交互に反転しつつ8回以上くり返し印
加して、塗膜中の磁性粉を振動させ、非磁性支持体の長
手方向と磁界とがなす角が10〜80°にて、磁性層中
の磁界が500〜2000Gとなるようにして、前記グ
ラビア塗布のグラビアパターンを平滑化することを特徴
とする磁気記録媒体の製造方法。 (2) 長尺の非磁性支持体を連続的に移動させなが
ら、磁性粉とバインダとを含有する磁性層用塗布組成物
を塗布し、塗膜表面にスムージング手段を接触させた
後、前記非磁性支持体の一面側に、非磁性支持体の移動
方向に対して傾斜しているグラビアパターンと磁界成分
が一致しないよう単位磁石を非磁性支持体の移動方向と
傾斜するように複数配置し、この単位磁石は前記非磁性
支持体の一面側に一方の磁極のみが位置しており、相隣
接する磁極が互いに異なり、前記単位磁石の長さ方向
が、前記非磁性支持体と平行でその長手方向と傾斜する
ように、前記非磁性支持体に対向して配置し、前記非磁
性支持体の移動方向と傾斜した前記単位磁石間の磁界を
交互に反転しつつ8回以上くり返し印加して、塗膜中の
磁性粉を振動させ、非磁性支持体の長手方向と磁界とが
なす角が10〜80°にて、磁性層中の磁界が500〜
2000Gとなるようにして平滑化を行う上記(1)に
記載の磁気記録媒体の製造方法。 (3) 長尺の非磁性支持体を連続的に移動させなが
ら、磁性粉と、モース硬度6以上の非磁性研磨材と、バ
インダとを含有する磁性層用塗布組成物を塗布した後、
非磁性支持体の一面側に、非磁性支持体の移動方向に対
して傾斜しているグラビアパターンと磁界成分が一致し
ないよう単位磁石を非磁性支持体の移動方向と傾斜する
ように複数配置し、この単位磁石は前記非磁性支持体の
一面側に一方の磁極のみが位置しており、相隣接する磁
極が互いに異なり、前記単位磁石の長さ方向が、前記非
磁性支持体と平行でその長手方向と傾斜するように、前
記非磁性支持体に対向して配置し、前記非磁性支持体の
移動方向と傾斜した前記単位磁石間の磁界を交互に反転
しつつくり返し印加して、塗膜中の磁性粉を振動させ、
表層部にて、前記非磁性研磨材が他の部分より高密度に
含有されている磁性層を形成することを特徴とする磁気
記録媒体の製造方法。 (4) 前記磁性層の厚さが4μm 以下であり、前記磁
性層中に、前記非磁性研磨材が、前記磁性粉に対し5〜
20重量%含有されており、前記磁性層の表面から0.
6μm の厚みの表層部の非磁性研磨材の含有密度をρ
1 、残部の非磁性研磨材の含有密度をρ2 としたとき、
ρ1 /ρ2 が1.5以上である上記(3)に記載の磁気
記録媒体の製造方法。 (5) 前記非磁性研磨材の平均粒径が0.6μm 以下
でありρ1 が8〜25%である上記(3)または(4)
に記載の磁気記録媒体の製造方法。 (6) 複数の単位磁石を、相隣接する単位磁石同志の
非磁性支持体対向面の極性が異なり、前記単位磁石の長
さ方向が、前記非磁性支持体と平行でその長手方向と傾
斜するように、前記非磁性支持体の塗布面と反対側に配
置する上記(3)ないし(5)のいずれかに記載の磁気
記録媒体の製造方法。 (7) 前記単位磁石による外部磁場を作用させたの
ち、磁性粉の配向を行う上記(1)ないし(6)のいず
れかに記載の磁気記録媒体の製造方法。This and other objects are achieved by the present invention which is defined below as (1) to (7). (1) While continuously moving the long non-magnetic support, after gravure-coating the coating composition for a magnetic layer containing a magnetic powder and a binder, one surface of the non-magnetic support is
A plurality of unit magnets are arranged so as to be inclined with respect to the moving direction of the non-magnetic support so that the magnetic field component does not coincide with the gravure pattern inclined with respect to the moving direction of the non-magnetic support. Only one magnetic pole is located on one surface side of the body, adjacent magnetic poles are different from each other, and the length direction of the unit magnet is parallel to the non-magnetic support and inclined with the longitudinal direction. The magnetic powder in the coating film is vibrated by repeatedly disposing the magnetic field between the unit magnets, which are arranged in opposition to the non-magnetic support and the tilted unit magnet, at least eight times while alternately reversing the magnetic field. And making the magnetic field in the magnetic layer 500 to 2000 G at an angle between the longitudinal direction of the nonmagnetic support and the magnetic field of 10 to 80 ° to smooth the gravure pattern of the gravure coating. Characteristic magnetic recording medium The method of production. (2) While continuously moving a long non-magnetic support, a coating composition for a magnetic layer containing a magnetic powder and a binder is applied, and a smoothing means is brought into contact with the surface of the coating film. On one side of the magnetic support, a plurality of unit magnets are arranged so as to be inclined with the moving direction of the nonmagnetic support so that the gravure pattern and the magnetic field component that are inclined with respect to the moving direction of the nonmagnetic support do not match, In this unit magnet, only one magnetic pole is located on one surface side of the non-magnetic support, adjacent magnetic poles are different from each other, and the length direction of the unit magnet is parallel to the non-magnetic support and the longitudinal direction thereof. As inclined with respect to the direction, arranged opposite to the non-magnetic support, repeatedly applying the magnetic field between the unit magnet and the direction of movement of the non-magnetic support alternately more than eight times while alternately reversing the magnetic field, Vibrates the magnetic powder in the coating to make it non-magnetic When the angle between the longitudinal direction of the support and the magnetic field is 10 to 80 °, the magnetic field in the magnetic layer is 500 to
The method for producing a magnetic recording medium according to the above (1), wherein the smoothing is performed to 2000 G. (3) While continuously moving the long non-magnetic support, after applying a magnetic layer coating composition containing a magnetic powder, a non-magnetic abrasive having a Mohs hardness of 6 or more, and a binder,
On one side of the non-magnetic support, a plurality of unit magnets are arranged so as to be inclined with respect to the moving direction of the non-magnetic support so that the magnetic field component does not match the gravure pattern inclined with respect to the moving direction of the non-magnetic support. In this unit magnet, only one magnetic pole is located on one surface side of the non-magnetic support, adjacent magnetic poles are different from each other, and the length direction of the unit magnet is parallel to the non-magnetic support. It is disposed opposite to the non-magnetic support so as to be inclined with respect to the longitudinal direction, and the magnetic field between the unit magnets inclined and the direction of movement of the non-magnetic support is alternately reversed and applied repeatedly while applying a magnetic field. Vibrating the magnetic powder inside,
A method for manufacturing a magnetic recording medium, comprising: forming a magnetic layer in the surface layer portion, wherein the non-magnetic abrasive is contained at a higher density than other portions. (4) The thickness of the magnetic layer is 4 μm or less, and the non-magnetic abrasive in the magnetic layer is 5 to 5% of the magnetic powder.
20% by weight, and 0.1% from the surface of the magnetic layer.
The density of the non-magnetic abrasive in the surface layer having a thickness of 6 μm is defined as ρ
1, when the content density of the non-magnetic abrasive remainder was [rho 2,
The method for producing a magnetic recording medium according to the above (3), wherein ρ 1 / ρ 2 is 1.5 or more. (5) The above (3) or (4), wherein the nonmagnetic abrasive has an average particle size of 0.6 μm or less and ρ1 of 8 to 25%.
3. The method for manufacturing a magnetic recording medium according to claim 1. (6) The plurality of unit magnets are adjacent to each other and have different polarities on the non-magnetic support-facing surfaces, and the length direction of the unit magnets is parallel to the non-magnetic support and inclined with respect to the longitudinal direction. As described above, the method for producing a magnetic recording medium according to any one of the above (3) to (5), wherein the magnetic recording medium is arranged on a side opposite to a coating surface of the nonmagnetic support. (7) The method of manufacturing a magnetic recording medium according to any one of (1) to (6), wherein the magnetic powder is oriented after an external magnetic field is applied by the unit magnet.
【0010】(1)長尺の非磁性支持体を連続的に移動
させながら、磁性粉とバインダとを含有する磁性層用塗
布組成物をグラビア塗布した後、前記非磁性支持体の移
動方向と傾斜した磁界を反転しつつ4回以上くり返し印
加して、塗膜中の磁性粉を振動させ、前記グラビア塗布
のグラビアパターンを平滑化することを特徴とする磁気
記録媒体の製造方法。(1) While continuously moving a long non-magnetic support, a coating composition for a magnetic layer containing a magnetic powder and a binder is gravure-coated, and then the direction of movement of the non-magnetic support is determined. A method for manufacturing a magnetic recording medium, characterized in that a magnetic powder in a coating film is vibrated by applying a tilted magnetic field repeatedly while inverting it four times or more to smooth the gravure pattern of the gravure coating.
【0011】(2)長尺の非磁性支持体を連続的に移動
させながら、磁性粉とバインダとを含有する磁性層用塗
布組成物を塗布し、塗膜表面にスムージング手段を接触
させた後、前記非磁性支持体の移動方向と傾斜した磁界
を反転しつつ4回以上くり返し印加して、塗膜中の磁性
粉を振動させ、前記スムージング手段による長手方向の
スジを平滑化することを特徴とする磁気記録媒体の製造
方法。(2) After a long non-magnetic support is continuously moved, a coating composition for a magnetic layer containing a magnetic powder and a binder is applied, and a smoothing means is brought into contact with the surface of the coating. Applying a magnetic field inclined in the direction of movement of the non-magnetic support and inclining four or more times while inverting the magnetic field in the coating film to vibrate the magnetic powder in the coating film and smoothing the longitudinal stripes by the smoothing means. A method for manufacturing a magnetic recording medium.
【0012】(3)複数の単位磁石を、相隣接する単位
磁石同志の非磁性支持体対向面の極性が異なり、前記単
位磁石の長さ方向が、前記非磁性支持体の長手方向と傾
斜するように、前記非磁性支持体に対向して配置する上
記(1)または(2)に記載の磁気記録媒体の製造方
法。(3) The plurality of unit magnets are adjacent to each other and have different polarities on the non-magnetic support-facing surface, and the length direction of the unit magnets is inclined with respect to the longitudinal direction of the non-magnetic support. The method of manufacturing a magnetic recording medium according to the above (1) or (2), wherein the magnetic recording medium is disposed so as to face the nonmagnetic support.
【0013】(4)長尺の非磁性支持体を連続的に移動
させながら、磁性粉と、モース硬度6以上の非磁性研磨
材と、バインダとを含有する磁性層用塗布組成物を塗布
した後、前記非磁性支持体の移動方向と傾斜した磁界を
反転しつつくり返し印加して、塗膜中の磁性粉を振動さ
せ、表層部にて、前記非磁性研磨材が他の部分より高密
度に含有されている磁性層を形成することを特徴とする
磁気記録媒体の製造方法。(4) A coating composition for a magnetic layer containing a magnetic powder, a nonmagnetic abrasive having a Mohs hardness of 6 or more, and a binder was applied while continuously moving a long nonmagnetic support. Thereafter, a magnetic field inclined in the direction of movement of the non-magnetic support is inverted and applied repeatedly to vibrate the magnetic powder in the coating film, so that the non-magnetic abrasive has a higher density in the surface layer than in other parts. Forming a magnetic layer contained in the magnetic recording medium.
【0014】(5)前記磁性層の厚さが4μm 以下であ
り、前記磁性層中に、前記非磁性研磨材が、前記磁性粉
に対し5〜20重量%含有されており、前記磁性層の表
面から0.6μm の厚みの表層部の非磁性研磨材の含有
密度をρ1 、残部の非磁性研磨材の含有密度をρ2 とし
たとき、ρ1 /ρ2 が1.5以上である上記(4)に記
載の磁気記録媒体の製造方法。(5) The thickness of the magnetic layer is 4 μm or less, and the magnetic layer contains 5 to 20% by weight of the nonmagnetic abrasive based on the magnetic powder. When the content density of the nonmagnetic abrasive in the surface layer having a thickness of 0.6 μm from the surface is ρ 1 and the content density of the remaining nonmagnetic abrasive is ρ 2 , ρ 1 / ρ 2 is 1.5 or more. The method for manufacturing a magnetic recording medium according to the above (4).
【0015】(6)前記非磁性研磨材の平均粒径が0.
6μm 以下でありρ1 が8〜25%である上記(4)ま
たは(5)に記載の磁気記録媒体の製造方法。(6) The non-magnetic abrasive has an average particle size of 0.1.
The method for producing a magnetic recording medium according to (4) or (5), wherein the magnetic recording medium has a thickness of 6 μm or less and ρ1 of 8 to 25%.
【0016】(7)複数の単位磁石を、相隣接する単位
磁石同志の非磁性支持体対向面の極性が異なり、前記単
位磁石の長さ方向が、前記非磁性支持体の長手方向と傾
斜するように、前記非磁性支持体の塗布面と反対側に配
置する上記(4)ないし(6)のいずれかに記載の磁気
記録媒体の製造方法。(7) The unit magnets adjacent to each other have different polarities on the nonmagnetic support facing surfaces of adjacent unit magnets, and the length direction of the unit magnets is inclined with respect to the longitudinal direction of the nonmagnetic support. As described above, the method of manufacturing a magnetic recording medium according to any one of the above (4) to (6), wherein the magnetic recording medium is arranged on a side opposite to a coating surface of the nonmagnetic support.
【0017】(8)前記外部磁場を作用させたのち、磁
性粉の配向を行う上記(1)ないしだけで、該当する全
てのプロセス入力点情報を抽出して一覧表示することが
でき、(7)のいずれかに記載の磁気記録媒体の製造方
法。 (9)非磁性支持体の長手方向と磁界とがなす角が10
〜80゜である上記(1)〜(8)のいずれかに記載の
磁気記録媒体の製造方法。(8) After the above-mentioned external magnetic field is applied, the orientation of the magnetic powder is performed, and only the above (1) or above can extract all applicable process input point information and display it in a list. The method for manufacturing a magnetic recording medium according to any one of the above. (9) The angle between the longitudinal direction of the nonmagnetic support and the magnetic field is 10
The method for manufacturing a magnetic recording medium according to any one of the above (1) to (8), wherein the angle is 80 to 80 °.
【0018】[0018]
【作用】本発明における斜め磁界を反転しつつくり返し
印加することにより、塗膜表面の長手スジあるいはグラ
ビアパターンといった塗膜欠陥を消滅させ、表面性が向
上し、塗膜の品質が向上し、さらには歩留りの向上が望
める。In the present invention, the repetitive application of the oblique magnetic field while inverting the coating eliminates coating defects such as longitudinal streaks or gravure patterns on the coating surface, improves the surface properties and improves the quality of the coating. Can improve the yield.
【0019】また、斜め磁界を反転しつつくり返し印加
することにより、特に薄層化した単層の磁性層におい
て、磁性層中の研磨材の全体量を少なくしても、少量の
研磨材を磁性層の表層部に浮き上らせ、研磨材含有量を
表層部から支持体側に向けて連続的に減少させることが
できる。この結果、高い信頼性や耐久性を確保でき、し
かも薄層高密度記録用磁性層の高い電磁変換特性が維持
される。この際、配向前に斜め反転磁界を作用させて、
磁性塗料を移動させ、磁性粉を支持体側に引っ張ること
で相対的に表面に研磨材を多く分布させるので、塗膜の
脱泡効果や、配向効果も発揮され、電磁変換特性がより
一層向上するものである。Further, by repeatedly applying the oblique magnetic field while reversing the magnetic field, a small amount of the abrasive can be reduced even if the total amount of the abrasive in the magnetic layer is reduced, especially in the case of a thin single-layer magnetic layer. The abrasive content can be continuously reduced from the surface layer toward the support by floating on the surface layer of the layer. As a result, high reliability and durability can be secured, and the high electromagnetic conversion characteristics of the thin high-density recording magnetic layer are maintained. At this time, an oblique reversal magnetic field is applied before orientation,
By moving the magnetic paint and pulling the magnetic powder toward the support, a relatively large amount of abrasive is distributed on the surface, so that the defoaming effect and the orientation effect of the coating film are also exhibited, and the electromagnetic conversion characteristics are further improved. Things.
【0020】[0020]
【具体的構成】以下、本発明の具体的構成を詳細に説明
する。本発明では、非磁性支持体上に、バインダ中に、
好ましくは研磨材を添加して、磁性粉を分散させた磁性
塗料を塗設する。用いる磁性粉には、通常のものは何れ
も使用でき、例えば、γ−Fe2 O3 等の酸化鉄粒子、
Co含有γ−Fe2 O3 等のCo含有酸化鉄粒子、金属
磁性粒子、バリウムないしストロンチウムフェライト粒
子、CrO2 等が挙げられ、目的に応じて適宜選択すれ
ばよく、保磁力、残留磁化、比表面積等も目的に応じて
適宜選択すればよい。また、用いる磁性粉は、通常、針
状形態あるいは粒状形態のものであり、磁気記録媒体と
して用いる用途によって選択される。[Specific Configuration] Hereinafter, a specific configuration of the present invention will be described in detail. In the present invention, on a non-magnetic support, in a binder,
Preferably, an abrasive is added and a magnetic paint in which magnetic powder is dispersed is applied. As the magnetic powder to be used, any of ordinary ones can be used, for example, iron oxide particles such as γ-Fe 2 O 3 ,
Co-containing iron oxide particles, such as Co-containing γ-Fe 2 O 3 , metal magnetic particles, barium or strontium ferrite particles, CrO 2, etc., may be appropriately selected depending on the purpose, and the coercive force, residual magnetization, ratio The surface area and the like may be appropriately selected depending on the purpose. The magnetic powder to be used is usually in a needle form or a granular form, and is selected depending on the use as a magnetic recording medium.
【0021】本発明に用いるバインダには、通常の磁気
記録媒体に用いられているものは何れも使用できる。例
えば、熱可塑性バインダ、熱硬化性バインダ、電子線硬
化性バインダ等が挙げられる。そして、磁性粉1重量部
に対するバインダの含有量は、0.1〜0.3重量部程
度が好ましい。As the binder used in the present invention, any binder used for ordinary magnetic recording media can be used. For example, a thermoplastic binder, a thermosetting binder, an electron beam curable binder, and the like can be given. The content of the binder per 1 part by weight of the magnetic powder is preferably about 0.1 to 0.3 parts by weight.
【0022】本発明では研磨材として、モース硬度6以
上の非磁性研磨材を用いることが好ましい。このような
非磁性研磨材としては、アルミナAl2 O3 、非磁性酸
化クロムCr2 O3 、炭化ケイ素SiC、酸化チタンT
iO2 、シリカSiO2 、ジルコニアZrO2 の1種ま
たは2種以上が挙げられ、これらのうちでは、研磨材の
分散性あるいは、ヘッド摩耗の点で、Al2 O3 、Cr
2 O3 およびSiCの1種以上を含むものが好ましい。
これら研磨材の平均粒径は0.6μm 以下、特に0.1
〜0.4μm であることが好ましい。0.6μm をこえ
ると、電磁変換特性が低下し、また小粒径すぎると耐久
性の点で不十分である。なお、研磨材の粒子形状では、
球状、角状等種々のものであってよく、通常は、TEM
像の投影面積から、円仮定して算出すればよい。In the present invention, it is preferable to use a non-magnetic abrasive having a Mohs hardness of 6 or more as the abrasive. Examples of such non-magnetic abrasives include alumina Al 2 O 3 , non-magnetic chromium oxide Cr 2 O 3 , silicon carbide SiC, and titanium oxide T
One or more of iO 2 , silica SiO 2 , and zirconia ZrO 2 may be mentioned, and among these, Al 2 O 3 , Cr is preferable in terms of abrasive dispersibility or head wear.
Those containing at least one of 2 O 3 and SiC are preferred.
The average particle size of these abrasives is 0.6 μm or less, especially 0.1 μm.
It is preferably about 0.4 μm. When the thickness exceeds 0.6 μm, the electromagnetic conversion characteristics are deteriorated, and when the particle size is too small, the durability is insufficient. In addition, in the particle shape of the abrasive,
Various shapes such as a spherical shape and a square shape may be used.
The calculation may be performed by assuming a circle from the projected area of the image.
【0023】このような研磨材は、磁性層全体に、総計
で、磁性粉に対し5〜20重量%、特に8〜18重量
%、さらには10〜18重量%含有される。全体量が5
重量%未満では耐久安定性が低下する。また、20重量
%をこえると電磁変換特性が低下する。Such an abrasive is contained in the entire magnetic layer in a total amount of 5 to 20% by weight, particularly 8 to 18% by weight, and more preferably 10 to 18% by weight based on the magnetic powder. The total amount is 5
If the amount is less than the weight percentage, the durability stability decreases. On the other hand, if it exceeds 20% by weight, the electromagnetic conversion characteristics deteriorate.
【0024】このような研磨材は、通常単層構造の磁性
層中の表層部に偏在することが好ましい。すなわち、研
磨材の含有密度は、表層部にて最も高く、支持体側にて
最も低い。そして、表層部から支持体側に向かって含有
密度が連続的に変化する傾斜領域を有することが好まし
い。It is preferable that such an abrasive is usually unevenly distributed in the surface layer portion of the magnetic layer having a single-layer structure. That is, the content density of the abrasive is highest on the surface layer portion and lowest on the support side. And it is preferable to have an inclined region in which the content density changes continuously from the surface layer portion toward the support.
【0025】より具体的には、表面から0.6μm の厚
みの表層部の含有密度をρ1 、残部の含有密度をρ2 と
したとき、ρ1 /ρ2 は1.5以上、より好ましくは
1.5〜10となるようにすることが好ましい。ρ1/ρ
2 が1.5未満では、本発明の効果が減少する傾向にあ
る。ただしあまり大きいと磁性層の補強効果が不十分と
なる傾向にある。この場合、含有密度は、磁性層の断面
TEM像を観察したとき、磁性層の所定領域中に占める
研磨材の投影面積%であり、添加研磨材量にもよるが、
ρ1 は8〜25%、特に10〜20%とすることが好ま
しい。ρ1 が小さいと耐久性が低下する傾向にあり、大
きすぎると電磁変換特性が低下する傾向にある。More specifically, ρ 1 / ρ 2 is 1.5 or more, more preferably 1.5 or more, where ρ 1 is the content density of the surface layer having a thickness of 0.6 μm from the surface and ρ 2 is the content density of the remaining portion. Is preferably set to 1.5 to 10. ρ 1 / ρ
If 2 is less than 1.5, the effect of the present invention tends to decrease. However, if it is too large, the effect of reinforcing the magnetic layer tends to be insufficient. In this case, the content density is a projected area% of the abrasive occupying a predetermined region of the magnetic layer when a cross-sectional TEM image of the magnetic layer is observed, and depends on the amount of the added abrasive.
[rho 1 is preferably set to 8-25%, especially 10-20%. tend to durability is decreased [rho 1 is small, tends to too large, the electromagnetic conversion characteristics decreased.
【0026】なお、磁性層全体における研磨材の含有密
度は、添加量5〜20重量%にて、通常2〜8%程度で
あり、従来の均一層にて研磨材の含有密度10%の磁性
層を形成するには、研磨材を25重量%程度添加しなけ
ればならない。そして、本発明の磁気記録媒体の場合、
10〜20%の含有密度を有する高密度領域は、一般に
0.3〜1.0μm 程度であり、この領域の支持体側に
通常、連続勾配にて密度の減少する傾斜ないし遷移領域
を有することが好ましい。The content density of the abrasive in the entire magnetic layer is usually about 2 to 8% when the added amount is 5 to 20% by weight. To form a layer, about 25% by weight of an abrasive must be added. And in the case of the magnetic recording medium of the present invention,
The high-density region having a content density of 10 to 20% is generally about 0.3 to 1.0 μm, and it is usually possible to have a slope or transition region in which the density decreases with a continuous gradient on the support side of this region. preferable.
【0027】このような磁性層には、公知の各種帯電防
止剤 潤滑剤、分散剤、塗膜強度補強添加剤を用途に合
わせて使用することが有効である。なお、磁性層の厚み
は、好ましくは4μm 以下、特に1.0〜4.0μm 程
度とする。For such a magnetic layer, it is effective to use various known antistatic agents, lubricants, dispersants, and additives for reinforcing the strength of the coating film according to the intended use. The thickness of the magnetic layer is preferably 4 μm or less, particularly about 1.0 to 4.0 μm.
【0028】さらに、磁性層中の空孔率は7%以下、通
常2〜7%程度である。空孔率は、例えば磁性粉の飽和
磁化σS と媒体の残留磁束密度Brとの比較によって算
出することができ、また磁性層断面のSEM像からも求
めることができる。また、本発明では、磁性層は通常上
記の研磨材含有密度プロファイルを有する単層膜である
が、場合によっては、この単層膜の支持体側に下地磁性
層を設層したものであってもよい。そして、本発明の媒
体は、非磁性支持体の一方の面のみに、このような磁性
層を有するものであってもよく、また、後述の外部磁場
印加は磁性層形成ごとに行えばよいので、いわゆる両面
媒体であってもよい。The porosity in the magnetic layer is 7% or less, usually about 2 to 7%. The porosity can be calculated, for example, by comparing the saturation magnetization σ S of the magnetic powder with the residual magnetic flux density Br of the medium, and can also be obtained from the SEM image of the cross section of the magnetic layer. Further, in the present invention, the magnetic layer is usually a single-layer film having the above-mentioned abrasive-containing density profile, but in some cases, a magnetic underlayer may be provided on the support side of the single-layer film. Good. The medium of the present invention may have such a magnetic layer only on one surface of the non-magnetic support, and the external magnetic field application described later may be performed each time the magnetic layer is formed. It may be a so-called double-sided medium.
【0029】本発明の磁気記録媒体に用いる非磁性支持
体に特に制限はなく、目的に応じて各種可撓性材質、各
種剛性材質から選択した材料を、各種規格に応じてテー
プ状などの所定形状および寸法とすればよい。例えば、
可撓性材質としては、ポリエチレンテレフタレート等の
ポリエステルが挙げられる。なお、必要に応じて、下地
層や非磁性基体の磁性層と反対側にバックコート層等を
設けてもよい。バックコート層に制限はなく、導電性フ
ィラー、各種顔料などを含有する公知の塗布型バックコ
ート層であってよく、また、プラズマ重合膜をバックコ
ート層として用いてもよい。There is no particular limitation on the non-magnetic support used for the magnetic recording medium of the present invention, and a material selected from various flexible materials and various rigid materials according to the purpose may be used in a predetermined form such as a tape shape according to various standards. The shape and the size may be set. For example,
Examples of the flexible material include polyester such as polyethylene terephthalate. If necessary, a back coat layer or the like may be provided on the opposite side of the underlayer or the magnetic layer of the non-magnetic substrate. The back coat layer is not limited, and may be a known coating type back coat layer containing a conductive filler, various pigments, and the like, or a plasma polymerized film may be used as the back coat layer.
【0030】このような磁気記録媒体を得るには、ま
ず、所定の組成の磁性塗料を磁性層用塗布組成物として
調製する。次いで、この磁性塗料を長尺の非磁性支持体
3上に塗布する。塗布はリバース方式やグラビア方式等
を用いる。そして、必要に応じ、塗膜表面にスムージン
グ手段を接触させる。In order to obtain such a magnetic recording medium, first, a magnetic paint having a predetermined composition is prepared as a coating composition for a magnetic layer. Next, this magnetic paint is applied on the long non-magnetic support 3. The application is performed by a reverse method, a gravure method, or the like. Then, if necessary, a smoothing means is brought into contact with the coating film surface.
【0031】次いで、未乾燥の間に、連続的に磁界の方
向が反転する斜め外部磁場を作用させる。用いる外部磁
場印加手段の磁界発生手段は任意であり、例えば永久磁
石や電磁石等が挙げられる。Next, during the drying, an oblique external magnetic field in which the direction of the magnetic field is continuously reversed is applied. The magnetic field generating means of the external magnetic field applying means used is arbitrary, and examples thereof include a permanent magnet and an electromagnet.
【0032】ここで本発明に好適な外部磁場印加手段の
1例を図1および図2に示す。図1、図2に示される外
部磁場印加手段5は、非磁性支持体3の塗布面と反対側
の裏面側に、複数の単位磁石4を、相隣接する単位磁石
同志の極性が異なるように配置して構成されている。配
置する単位磁石4の個数は、磁界反転回数と対応するも
のであり、4個以上、特に8個以上25個以下程度が好
ましい。反転回数が少ないと、表面欠陥解消効果がなく
なってくる。また、所定の研磨材分布プロファイルが得
られにくい。また、あまりに多くの反転回数は不要であ
り、表面が粗くならない程度が好ましい。Here, one example of the external magnetic field applying means suitable for the present invention is shown in FIGS. The external magnetic field applying means 5 shown in FIGS. 1 and 2 is configured such that a plurality of unit magnets 4 are provided on the back surface opposite to the application surface of the nonmagnetic support 3 so that adjacent unit magnets have different polarities. It is arranged and configured. The number of unit magnets 4 to be arranged corresponds to the number of magnetic field reversals, and is preferably 4 or more, especially about 8 or more and about 25 or less . If the number of reversals is small, the effect of eliminating surface defects is lost. Further, it is difficult to obtain a predetermined abrasive distribution profile. Also, an excessively large number of inversions is unnecessary, and it is preferable that the surface is not roughened.
【0033】各単位磁石4は、図2に示されるように、
テープ1の非磁性支持体の巾より長い長さをもち、各単
位磁石4は、非磁性支持体と平行に、しかもその搬送方
向と傾斜して配置されている。この結果、テープ1に
は、図中矢印で示される斜め反転磁界が交互に印加され
る。なお、各単位磁石4は、必ずしも支持体3より広巾
の長さをもたなくてもよく、単位磁石4の集合体が全体
として支持体3より広巾であればよい。Each unit magnet 4 is, as shown in FIG.
Each unit magnet 4 has a length longer than the width of the non-magnetic support of the tape 1, and each unit magnet 4 is arranged parallel to the non-magnetic support and inclined with respect to the transport direction. As a result, an oblique reversal magnetic field indicated by an arrow in the figure is alternately applied to the tape 1. Note that each unit magnet 4 does not necessarily have to have a width wider than the support 3, and it is sufficient that the aggregate of the unit magnets 4 is wider than the support 3 as a whole.
【0034】グラビアパターンあるいは長手スジなどの
長短のスジ故障等の各種塗膜欠陥に対しては、塗料自体
のレベリングがきわめて難しい。そこで、本発明では、
外部から斜め反転磁界を磁性粉に作用させることによっ
て、塗膜自体を振動させたところ、表面欠陥が解消した
のである。It is extremely difficult to level the paint itself for various coating film defects such as gravure patterns or short and long streak failures such as long streaks. Therefore, in the present invention,
When the coating film itself was vibrated by applying an oblique reversal magnetic field to the magnetic powder from the outside, the surface defect was eliminated.
【0035】すなわち、この外部磁場印加手段5は、別
の観方をすれば非接触型のスムージング手段でもある。
この場合、N−S極の連続反転斜め磁界の磁界成分は、
長手スジ、あるいはグラビアパターンに一致しないよう
にする。より具体的には、長手スジ、あるいは図4に示
されるグラビアパターンGPといった塗膜欠陥の解消に
有効な磁界の方向は、図4に矢印で示されるように、そ
れらに対して直角な方向である。従って、磁界ベクトル
を分解した際、その分力がこれらと直角方向に存在する
ように設置する。この場合、図3に示されるように、磁
界Hと、非磁性支持体3の搬送方向MDとのなす角θ
は、10〜80゜程度とする。この場合、0゜が平行磁
界であり、θ>0が傾斜ないし斜め磁界である。ただ
し、研磨材を表面付近に多く存在させるためには、θ=
0については、特願平1−342988号にて既に提案
しているので、本発明では、θ=0を除外する。θ>0
により、このような効果は増大する。That is, the external magnetic field applying means 5 is also a non-contact type smoothing means from another viewpoint.
In this case, the magnetic field component of the continuously inverted oblique magnetic field of the NS pole is
Do not match the longitudinal streak or gravure pattern. More specifically, the direction of the magnetic field effective for eliminating coating defects such as longitudinal stripes or the gravure pattern GP shown in FIG. 4 is, as shown by the arrow in FIG. is there. Therefore, when the magnetic field vectors are decomposed, the components are set so that the component force exists in a direction perpendicular to these components. In this case, as shown in FIG. 3, the angle θ between the magnetic field H and the transport direction MD of the nonmagnetic support 3
Is about 10 to 80 °. In this case, 0 ° is a parallel magnetic field, and θ> 0 is an inclined or oblique magnetic field. However, in order to allow a large amount of abrasive to be present near the surface, θ =
Since 0 has already been proposed in Japanese Patent Application No. 1-342988, θ = 0 is excluded in the present invention. θ> 0
As a result, such an effect is increased.
【0036】なお、単位磁石4は、図示のように隣接し
て配置しても、所定の間隙を介して配置してもよい。ま
た、各単位磁石4は、磁界強度およびサイズが等しいも
のを用いるのが有利である。この場合、用いる単位磁石
4は、テープ巾方向に亘り均一な磁界が作用される限り
において任意であり、後述の反転サイクルに応じた寸法
とすればよい。そして、単位磁石4の最大エネルギー積
(BH)max は、3.5〜37 MGOe 程度が好ましい。
また、テープ1と外部磁場印加手段5の間隔は通常3〜
20mm程度である。このようにして磁性層2中の磁界の
強さを好ましくは300G以上、特に好ましくは500
〜2000G程度とする。The unit magnets 4 may be arranged adjacent to each other as shown, or may be arranged with a predetermined gap. Further, it is advantageous to use the unit magnets 4 having the same magnetic field strength and size. In this case, the unit magnet 4 to be used is optional as long as a uniform magnetic field is applied in the tape width direction, and may have a size corresponding to a reversal cycle described later. The maximum energy product (BH) max of the unit magnet 4 is preferably about 3.5 to 37 MGOe.
The interval between the tape 1 and the external magnetic field applying means 5 is usually 3 to
It is about 20 mm. In this way, the intensity of the magnetic field in the magnetic layer 2 is preferably 300 G or more, particularly preferably 500 G or more.
~ 2000G.
【0037】このような、外部磁場印加手段5を用い、
これに対向して、テープ1を搬送する。これにより、図
示のように未乾燥の磁性層2には、連続的に磁界の方向
が反転する外部磁場が作用される。このようにして、単
位磁石4からの磁束の方向が反転するごとに、塗布され
た磁性塗料中の磁性粉は反転しながら揺動し、また、磁
性塗料も揺動し、磁性粉は外部磁場印加手段側に周期的
に引き寄せられる。この際、非磁性研磨材は、これと相
対的に磁性層2の表層部に高密度に分布する。しかも、
表面は平滑化し、塗布欠陥が解消する。そして、磁性粉
はこのような揺動にともない、一種の予備配向処理を施
され、配向度が高まり、角形比が向上する。同時に、揺
動に伴い脱泡が行われ、空孔率が減少する。Using such an external magnetic field applying means 5,
In opposition to this, the tape 1 is transported. As a result, an external magnetic field whose direction of the magnetic field is continuously reversed is applied to the undried magnetic layer 2 as shown in the figure. In this way, every time the direction of the magnetic flux from the unit magnet 4 is reversed, the magnetic powder in the applied magnetic paint swings while inverting, and the magnetic paint also swings, and the magnetic powder is moved by the external magnetic field. It is periodically drawn to the application means side. At this time, the non-magnetic abrasive is relatively densely distributed on the surface of the magnetic layer 2. Moreover,
The surface is smoothed and coating defects are eliminated. Then, the magnetic powder is subjected to a kind of pre-orientation treatment in accordance with such oscillation, so that the degree of orientation is increased and the squareness ratio is improved. At the same time, defoaming is performed with the rocking, and the porosity decreases.
【0038】この場合、磁界の反転回数は、単位磁石4
の個数と同一であり、前記のとおり4個以上、特に8個
以上25個以下程度とする。また、磁界反転サイクルは
一般に50〜400回/秒程度とすればよい。In this case, the number of reversals of the magnetic field is determined by the unit magnet 4
The number is the same as above, and 4 or more, especially 8 as described above
More than about 25 or less . Further, the magnetic field reversal cycle may be generally set to about 50 to 400 times / second.
【0039】このような場合、図示例では、大略テープ
長手(搬送)方向ないしそれと傾斜する方向の外部磁界
を支持体裏面側から印加して、これを反転させている。
支持体の裏面側から作用させるのは、磁性粉を支持体側
で揺動させるためである。これに対し、塗膜面から作用
させるときには、塗膜表面側で揺動が生じ、研磨材は、
表面に浮上しない。これらから、図示例とは異なり、外
部磁場印加手段5を、支持体3の塗布面側と、裏面側の
双方に配置してもよいが、図示例のとおり裏面側のみに
配置した場合に特に研磨材の傾斜分布を作る点で効果が
高い。ただし、表面欠陥を解消するためには、表面側、
裏面側のいずれであっても、両者であってもよい。In such a case, in the illustrated example, an external magnetic field substantially in the longitudinal (conveying) direction of the tape or in a direction inclined thereto is applied from the back side of the support, and this is reversed.
The reason why the magnetic powder is applied from the back side of the support is to swing the magnetic powder on the support side. On the other hand, when acting from the coating film surface, rocking occurs on the coating film surface side, and the abrasive is
Does not float on the surface. From these, unlike the illustrated example, the external magnetic field applying means 5 may be arranged on both the coating surface side and the back surface side of the support 3, but especially when the external magnetic field applying means 5 is arranged only on the back surface side as shown in the illustrated example. It is highly effective in creating a gradient distribution of the abrasive. However, to eliminate surface defects,
Either of them may be on the back side or both.
【0040】次いで、配向用磁石6、6間にて、テープ
1を搬送させて長手方向配向を行う。この場合、配向用
磁石6は、外部磁場印加手段5と磁石が干渉しないよう
に離間させて配置する。また、配向用磁石6の磁性は、
通常、外部磁場印加手段5の最終段の単位磁石4の極性
と反対の極性とすることが好ましい。このようにすれば
配向をスムーズに行える。そして、磁性層2中の配向磁
界強度は、1500〜10000G程度が好適である。Next, the tape 1 is conveyed between the magnets 6 for orientation to perform longitudinal orientation. In this case, the magnet for orientation 6 is arranged so as to be separated from the external magnetic field applying means 5 so as not to interfere with the magnet. The magnetism of the magnet for orientation 6 is as follows.
Usually, it is preferable that the polarity is opposite to the polarity of the unit magnet 4 in the last stage of the external magnetic field applying means 5. In this way, the alignment can be performed smoothly. The orientation magnetic field strength in the magnetic layer 2 is preferably about 1500 to 10000 G.
【0041】これらの後、カレンダー加工等の表面平滑
処理を経て、硬化される。そして、これをスリッター等
により所定寸法に切断して、磁気テープ等としたり、配
向処理をランダム配向処理に置き換えて原反を得、これ
を打ち抜いてフロッピーディスクを得たりすればよい。After that, it is cured through a surface smoothing treatment such as calendering. Then, this may be cut into a predetermined size by a slitter or the like to obtain a magnetic tape or the like, or a raw film may be obtained by replacing the alignment process with a random alignment process, and a floppy disk may be obtained by punching the raw material.
【0042】[0042]
【実施例】以下、本発明の具体的実施例を挙げ、本発明
をさらに詳細に説明する。EXAMPLES Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention.
【0043】実施例1 下記に示される配合比で磁性塗料を調製した。Example 1 A magnetic coating material was prepared at the compounding ratio shown below.
【0044】 金属磁性粉 100重量部 平均長径:0.2μm 平均軸比:8 Hc :1500 Oe σS :130emu/g 塩化ビニル−酢酸ビニル−ビニルアルコール共重合体 (UCC社製 VAGH) 10重量部 ポリウレタン樹脂(日本ポリウレタン社製 N-2304) 10重量部 低分子量ポリイソシアネート化合物(日本ポリウレタン社製 コロネートL) 5重量部 研磨材 3〜30重量部 ステアリン酸 0.2重量部 レシチン 0.5重量部 トルエン 50重量部 メチルエチルケトン 50重量部 メチルイソブチルケトン 50重量部100 parts by weight of metal magnetic powder Average major axis: 0.2 μm Average axis ratio: 8 Hc: 1500 Oe σ S : 130 emu / g Vinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) 10 parts by weight Polyurethane resin (N-2304 manufactured by Nippon Polyurethane) 10 parts by weight Low molecular weight polyisocyanate compound (Coronate L manufactured by Nippon Polyurethanes) 5 parts by weight Abrasives 3 to 30 parts by weight Stearic acid 0.2 parts by weight Lecithin 0.5 parts by weight Toluene 50 parts by weight Methyl ethyl ketone 50 parts by weight Methyl isobutyl ketone 50 parts by weight
【0045】この場合、研磨材は平均粒径0.25μm
のCr2 O3 と、平均粒径0.20μm のAl2 O3 と
を重量比にて1:1で混合し、これを表1に示される重
量部で用いたものである。この磁性塗料を10μm 厚の
ポリエステルフィルム上にリバース方式で塗布し、外部
磁界印加、配向、カレンダー加工後、熱硬化した。In this case, the abrasive has an average particle size of 0.25 μm.
Of Cr 2 O 3 and Al 2 O 3 having an average particle diameter of 0.20 μm were mixed at a weight ratio of 1: 1 and used in parts by weight shown in Table 1. This magnetic paint was applied on a 10 μm-thick polyester film by a reverse method, applied with an external magnetic field, oriented, calendered, and then heat-cured.
【0046】この場合、外部磁界印加は、図1、図2に
示される複数の単位磁石4を有する外部磁界印加手段5
を用いて行った。このとき、磁界方向Hと搬送方向MD
のなす角θは60°とした。単位磁石4のテープ搬送方
向長は20mmとしたので、単位磁石4のテープ搬送方向
長は40mmとなった。この際、各単位磁石の表面磁界は
同一のものとした。そして、単位磁石数を変更して、下
記表1に示される回数にて磁場を反転させた。なお、磁
場反転回数は、単位磁石数である。また、配向用磁石6
による磁性塗膜の配向磁界は4000Gとし、磁性層の
最終厚みは3.0μm とした。In this case, the external magnetic field is applied by an external magnetic field applying means 5 having a plurality of unit magnets 4 shown in FIGS.
This was performed using At this time, the magnetic field direction H and the transport direction MD
Is 60 °. Since the length of the unit magnet 4 in the tape transport direction was 20 mm, the length of the unit magnet 4 in the tape transport direction was 40 mm. At this time, the surface magnetic field of each unit magnet was the same. Then, the number of unit magnets was changed, and the magnetic field was inverted at the times shown in Table 1 below. The number of magnetic field reversals is the number of unit magnets. Also, the magnet for orientation 6
Was 4000 G, and the final thickness of the magnetic layer was 3.0 μm.
【0047】これをスリッターにより8mm幅に切断し
て、磁気テープサンプルを作製した。各サンプルの磁性
層の断面のTEM像を観察し、表面から0.6μm の表
層部のρ1 と残部のρ2 を求めた。ρ1 およびρ2 は、
断面中での研磨材の投影面積比である。なお、本発明の
サンプルNo. 1〜4では、表層から0.2μm 程度の位
置から、さらに0.2μm 程度の範囲が表記のρ1 をも
ち、この下方に傾斜層を有していた。This was cut into a width of 8 mm by a slitter to prepare a magnetic tape sample. Observing the TEM image of the cross section of the magnetic layer of each sample were determined [rho 1 and the remainder [rho 2 of the surface layer portion of 0.6μm from the surface. ρ 1 and ρ 2 are
This is the projected area ratio of the abrasive in the cross section. In addition, in Sample Nos. 1 to 4 of the present invention, a range of about 0.2 μm from the position of about 0.2 μm from the surface layer had ρ 1 as described above, and had an inclined layer below this.
【0048】また、比較用テープサンプルとして磁性層
の下層を塗布後、上層を積層してサンプルNo. 13を作
製した。この場合、下層には、磁性粉100重量部に対
し研磨材を12.5重量部含有させ、上層には研磨材を
25重量部含有させた。そして、磁性層の最終厚みは下
層2.4μm 、上層0.6μm とした。Further, as a comparative tape sample, a lower layer of the magnetic layer was applied, and an upper layer was laminated thereon, thereby preparing Sample No. 13. In this case, the lower layer contained 12.5 parts by weight of the abrasive with respect to 100 parts by weight of the magnetic powder, and the upper layer contained 25 parts by weight of the abrasive. The final thickness of the magnetic layer was 2.4 μm for the lower layer and 0.6 μm for the upper layer.
【0049】これら、各サンプルの角形比、Br 、空孔
率(%)を表1に示す。なお、空孔率はテープ残留磁束
密度Br から計算で求めた。また、各サンプルの5MHz
におけるRF出力を測定した。なお、RF出力は、サン
プルNo. 11の出力に対するdB値で表示した。Table 1 shows the squareness ratio, Br, and porosity (%) of each sample. The porosity was calculated from the residual magnetic flux density Br of the tape. 5MHz of each sample
The RF output at was measured. Note that the RF output was represented by a dB value with respect to the output of Sample No. 11.
【0050】また、各サンプルについて、スチル特性と
ヘッド目詰まりを評価した。スチル特性は常温(23
℃、65%RH)にて行い、2時間後の出力低下につい
て以下の判定基準で評価した。Further, still characteristics and head clogging of each sample were evaluated. Still characteristics are normal temperature (23
C., 65% RH), and the output decrease after 2 hours was evaluated according to the following criteria.
【0051】◎:RF出力低下1.0dB未満 ○:1.0dB以上2.0dB未満 △:2.0dB以上3.0dB未満 ×:3.0dB以上◎: RF output decrease less than 1.0 dB :: 1.0 dB or more and less than 2.0 dB Δ: 2.0 dB or more and less than 3.0 dB ×: 3.0 dB or more
【0052】また、ヘッド目詰まりは、高温高湿(40
℃、80%RH)下でパス走行を行い、以下の判定基準
で評価した。Further, clogging of the head is caused by high temperature and high humidity (40 ° C.).
C., 80% RH), and evaluated according to the following criteria.
【0053】◎:100パス以上発生せず。 ○:100未満50以上で発生 △: 50未満20以上で発生 ×: 20パス未満で発生A: No more than 100 passes occurred. :: Occurs when less than 100 and 50 or more △: Occurs when less than 50 and 20 or more X: Occurs when less than 20 passes
【0054】これらの結果を表1に示す。Table 1 shows the results.
【0055】[0055]
【表1】 [Table 1]
【0056】表1により本発明の効果が明らかである。Table 1 shows the effect of the present invention.
【0057】なお、比較サンプルNo. 13は、上層厚が
薄いため、カレンダー加工性が悪く、表面が粗くなり、
RF出力が低い。これに対し、本発明のサンプルNo. 1
〜No. 4は、電磁変換特性および耐久性それぞれが良好
であった。The comparative sample No. 13 had poor calendering workability and a rough surface because the upper layer was thin.
RF output is low. In contrast, the sample No. 1 of the present invention
No. 4 to No. 4 each had good electromagnetic conversion characteristics and durability.
【0058】実施例2 実施例1とほぼ同種のフロッピーディスク用磁性塗料を
使用し、リバース方式により磁性塗膜を乾燥後厚みで2
μm の厚さになるように塗布し、接触型スムージング装
置と接触させた。こののち、図1、図2に示されるよう
に、θ=45°、段数=7段、N−S磁界強さがベース
フィルム上にて1000Gの反転磁界を印加し、その後
配向を行ってサンプルを作製した。Example 2 Using the same type of magnetic paint for floppy disk as in Example 1, the magnetic coating was dried to a thickness of 2 by the reverse method.
It was applied to a thickness of μm and was brought into contact with a contact-type smoothing device. Thereafter, as shown in FIGS. 1 and 2, θ = 45 °, the number of steps = 7 steps, a switching magnetic field of 1000 G in NS magnetic field strength was applied on the base film, and then the sample was oriented. Was prepared.
【0059】比較例1 反転磁界印加を行なわなかった以外は実施例1と同一の
条件にてサンプルを作製した。このものでは、0.1μ
m の深さの長手スジが発生していた。Comparative Example 1 A sample was prepared under the same conditions as in Example 1 except that no reversal magnetic field was applied. In this case, 0.1μ
Longitudinal stripes with a depth of m were found.
【0060】実施例3 実施例2と同じ磁性塗料を使用し、45°の斜線型グラ
ビアシリンダーを用いて、グラビア・リバース方式にて
磁性塗膜を塗布し、その後、θ=45°(グラビアパタ
ーンに対して磁界方向が直角)、段数=10段、N−S
磁界強さがべースフィルム上にて1000Gの反転磁界
を印加し、その後配向を行なってサンプルを作製した。Example 3 The same magnetic paint as in Example 2 was used, and a magnetic coating film was applied by a gravure reverse method using a 45 ° oblique gravure cylinder, and then θ = 45 ° (gravure pattern) The direction of the magnetic field is at right angles), the number of stages = 10, NS
A switching field of 1000 G was applied on the base film with a magnetic field strength, and then orientation was performed to prepare a sample.
【0061】比較例2 反転磁界印加を行なわなかった以外は実施例3と同一の
条件にてサンプルを作製した。Comparative Example 2 A sample was produced under the same conditions as in Example 3 except that no reversal magnetic field was applied.
【0062】以上の4サンプルについて、3.5インチ
に打ち抜き、フロッピーディスクとし、ハイパス・モジ
ュレーションの測定と表面状態の評価を行なった。その
結果を表2に示す。なお、ハイパスモジュレーション
は、モジュレーション測定後、これをローパスフィルタ
ーにより、ローパス値とハイパス値に分離し、ハイパス
値の平均値をローパス値の平均値で除して100倍した
%値である。The above four samples were punched out to 3.5 inches, used as floppy disks, and measured for high-pass modulation and evaluated for surface condition. Table 2 shows the results. The high-pass modulation is a% value obtained by dividing the average of the high-pass value by the average of the low-pass value and multiplying the result by 100 by dividing the low-pass value and the high-pass value by a low-pass filter after the modulation measurement.
【0063】[0063]
【表2】 [Table 2]
【0064】表2に示される結果から、本発明の効果が
明らかである。From the results shown in Table 2, the effect of the present invention is clear.
【0065】[0065]
【発明の効果】本発明によれば、塗膜表面の長手スジ
や、グラビアパターンといった塗膜欠陥を消滅でき、表
面性が向上し、塗膜の品質が向上し、さらには歩留りの
向上が図れる。また、高い信頼性や耐久性を確保でき、
しかも薄層高密度記録用磁性層の高い電磁変換特性が維
持でき、磁性塗膜の脱泡効果や、配向効果が得られるた
め、電磁変換特性がより一層向上する。According to the present invention, coating defects such as longitudinal stripes and gravure patterns on the coating surface can be eliminated, the surface properties can be improved, the coating quality can be improved, and the yield can be improved. . In addition, high reliability and durability can be secured,
In addition, the high electromagnetic conversion characteristics of the thin magnetic layer for high-density recording can be maintained, and the defoaming effect and the orientation effect of the magnetic coating film can be obtained, so that the electromagnetic conversion characteristics are further improved.
【図1】本発明の磁気記録媒体製造方法を説明するため
の側面図である。FIG. 1 is a side view for explaining a magnetic recording medium manufacturing method of the present invention.
【図2】図1の平面図である。FIG. 2 is a plan view of FIG.
【図3】磁界方向と非磁性支持体の搬送方向との関係を
示す平面図である。FIG. 3 is a plan view illustrating a relationship between a magnetic field direction and a transport direction of a nonmagnetic support.
【図4】グラビアパターンと磁界との関係を示す平面図
である。FIG. 4 is a plan view showing a relationship between a gravure pattern and a magnetic field.
1 テープ 2 磁性層 3 非磁性支持体 4 単位磁石 5 外部磁界印加手段 6 配向用磁石 MD 移動方向 GP グラビアパターン H 磁界 DESCRIPTION OF SYMBOLS 1 Tape 2 Magnetic layer 3 Non-magnetic support 4 Unit magnet 5 External magnetic field application means 6 Orientation magnet MD Moving direction GP Gravure pattern H Magnetic field
───────────────────────────────────────────────────── フロントページの続き (72)発明者 茂原 邦正 東京都中央区日本橋一丁目13番1号 テ ィーディーケイ株式会社内 (56)参考文献 特開 昭61−267932(JP,A) 特開 昭58−141437(JP,A) 特開 昭53−64504(JP,A) 特開 昭58−12132(JP,A) 特開 平3−295030(JP,A) ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kunimasa Mohara 1-1-13 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation (56) References JP-A-61-267932 (JP, A) JP-A-58 JP-A-1441437 (JP, A) JP-A-53-64504 (JP, A) JP-A-58-12132 (JP, A) JP-A-3-295030 (JP, A)
Claims (7)
ながら、磁性粉とバインダとを含有する磁性層用塗布組
成物をグラビア塗布した後、 前記非磁性支持体の一面側に、非磁性支持体の移動方向
に対して傾斜しているグラビアパターンと磁界成分が一
致しないよう単位磁石を非磁性支持体の移動方向と傾斜
するように複数配置し、 この単位磁石は前記非磁性支持体の一面側に一方の磁極
のみが位置しており、相隣接する磁極が互いに異なり、
前記単位磁石の長さ方向が、前記非磁性支持体と平行で
その長手方向と傾斜するように、前記非磁性支持体に対
向して配置し、 前記非磁性支持体の移動方向と傾斜した前記単位磁石間
の磁界を交互に反転しつつ8回以上くり返し印加して、
塗膜中の磁性粉を振動させ、非磁性支持体の長手方向と
磁界とがなす角が10〜80°にて、磁性層中の磁界が
500〜2000Gとなるようにして、前記グラビア塗
布のグラビアパターンを平滑化することを特徴とする磁
気記録媒体の製造方法。1. A gravure coating of a coating composition for a magnetic layer containing a magnetic powder and a binder while continuously moving a long non-magnetic support, and then, on one surface side of the non-magnetic support, A plurality of unit magnets are arranged so as to be inclined with respect to the moving direction of the non-magnetic support so that the magnetic field component does not coincide with the gravure pattern inclined with respect to the moving direction of the non-magnetic support. Only one magnetic pole is located on one side of the body, adjacent magnetic poles are different from each other,
The unit magnet is disposed opposite to the non-magnetic support so that the length direction of the unit magnet is parallel to the non-magnetic support and inclined with respect to the longitudinal direction, and the unit magnet is inclined with the moving direction of the non-magnetic support. Repeatedly apply the magnetic field between the unit magnets at least eight times while alternately reversing it,
The magnetic powder in the coating film is vibrated so that the angle between the longitudinal direction of the non-magnetic support and the magnetic field is 10 to 80 °, and the magnetic field in the magnetic layer is 500 to 2000 G. A method for manufacturing a magnetic recording medium, comprising smoothing a gravure pattern.
ながら、磁性粉とバインダとを含有する磁性層用塗布組
成物を塗布し、塗膜表面にスムージング手段を接触させ
た後、 前記非磁性支持体の一面側に、非磁性支持体の移動方向
に対して傾斜しているグラビアパターンと磁界成分が一
致しないよう単位磁石を非磁性支持体の移動方向と傾斜
するように複数配置し、 この単位磁石は前記非磁性支持体の一面側に一方の磁極
のみが位置しており、相隣接する磁極が互いに異なり、
前記単位磁石の長さ方向が、前記非磁性支持体と平行で
その長手方向と傾斜するように、前記非磁性支持体に対
向して配置し、 前記非磁性支持体の移動方向と傾斜した前記単位磁石間
の磁界を交互に反転しつつ8回以上くり返し印加して、
塗膜中の磁性粉を振動させ、非磁性支持体の長手方向と
磁界とがなす角が10〜80°にて、磁性層中の磁界が
500〜2000Gとなるようにして平滑化を行う請求
項1に記載の磁気記録媒体の製造方法。2. A coating composition for a magnetic layer containing a magnetic powder and a binder is applied while continuously moving a long non-magnetic support, and a smoothing means is brought into contact with the coating film surface. A plurality of unit magnets are arranged on one surface side of the non-magnetic support so as to be inclined with the moving direction of the non-magnetic support so that the magnetic field component does not match the gravure pattern inclined with respect to the moving direction of the non-magnetic support. However, in this unit magnet, only one magnetic pole is located on one surface side of the nonmagnetic support, and adjacent magnetic poles are different from each other,
The unit magnet is disposed opposite to the non-magnetic support so that the length direction of the unit magnet is parallel to the non-magnetic support and inclined with respect to the longitudinal direction, and the unit magnet is inclined with the moving direction of the non-magnetic support. Repeatedly apply the magnetic field between the unit magnets at least eight times while alternately reversing it,
The magnetic powder in the coating film is vibrated so that the magnetic field in the magnetic layer has a magnetic field of 500 to 2000 G at an angle between the longitudinal direction of the non-magnetic support and the magnetic field of 10 to 80 ° and is smoothed. Item 2. The method for manufacturing a magnetic recording medium according to Item 1.
ながら、磁性粉と、モース硬度6以上の非磁性研磨材
と、バインダとを含有する磁性層用塗布組成物を塗布し
た後、 非磁性支持体の一面側に、非磁性支持体の移動方向に対
して傾斜しているグラビアパターンと磁界成分が一致し
ないよう単位磁石を非磁性支持体の移動方向と傾斜する
ように複数配置し、 この単位磁石は前記非磁性支持体の一面側に一方の磁極
のみが位置しており、相隣接する磁極が互いに異なり、
前記単位磁石の長さ方向が、前記非磁性支持体と平行で
その長手方向と傾斜するように、前記非磁性支持体に対
向して配置し、 前記非磁性支持体の移動方向と傾斜した前記単位磁石間
の磁界を交互に反転しつつくり返し印加して、塗膜中の
磁性粉を振動させ、 表層部にて、前記非磁性研磨材が他の部分より高密度に
含有されている磁性層を形成することを特徴とする磁気
記録媒体の製造方法。3. A method for coating a magnetic layer coating composition containing a magnetic powder, a nonmagnetic abrasive having a Mohs hardness of 6 or more, and a binder while continuously moving a long nonmagnetic support. A plurality of unit magnets are arranged on one surface side of the non-magnetic support so as to be inclined with respect to the moving direction of the non-magnetic support so that the magnetic field component does not match the gravure pattern inclined with respect to the moving direction of the non-magnetic support. However, in this unit magnet, only one magnetic pole is located on one surface side of the nonmagnetic support, and adjacent magnetic poles are different from each other,
The unit magnet is disposed opposite to the non-magnetic support so that the length direction of the unit magnet is parallel to the non-magnetic support and inclined with respect to the longitudinal direction, and the unit magnet is inclined with the moving direction of the non-magnetic support. A magnetic layer in which the magnetic powder in the coating film vibrates by repeatedly applying the magnetic field between the unit magnets while inverting the magnetic field alternately, and wherein the nonmagnetic abrasive is contained at a higher density than other portions in the surface layer portion Forming a magnetic recording medium.
前記磁性層中に、前記非磁性研磨材が、前記磁性粉に対
し5〜20重量%含有されており、前記磁性層の表面か
ら0.6μm の厚みの表層部の非磁性研磨材の含有密度
をρ1 、残部の非磁性研磨材の含有密度をρ2 としたと
き、ρ1 /ρ2 が1.5以上である請求項3に記載の磁
気記録媒体の製造方法。4. The magnetic layer has a thickness of 4 μm or less,
The magnetic layer contains the nonmagnetic abrasive in an amount of 5 to 20% by weight based on the magnetic powder, and the density of the nonmagnetic abrasive in the surface layer having a thickness of 0.6 μm from the surface of the magnetic layer. the [rho 1, when a 2-containing density [rho nonmagnetic abrasive balance method of manufacturing a magnetic recording medium according to claim 3 ρ 1 / ρ 2 is 1.5 or more.
m 以下でありρ1 が8〜25%である請求項3または4
に記載の磁気記録媒体の製造方法。5. The non-magnetic abrasive has an average particle size of 0.6 μm.
Claim m or less [rho 1 is 8 to 25% 3 or 4
3. The method for manufacturing a magnetic recording medium according to claim 1.
同志の非磁性支持体対向面の極性が異なり、前記単位磁
石の長さ方向が、前記非磁性支持体と平行でその長手方
向と傾斜するように、前記非磁性支持体の塗布面と反対
側に配置する請求項3ないし5のいずれかに記載の磁気
記録媒体の製造方法。6. A unit magnet according to claim 1, wherein the unit magnets adjacent to each other have different polarities on opposite surfaces of the non-magnetic support, and a length direction of the unit magnet is parallel to the non-magnetic support and a longitudinal direction of the unit magnet. The method for manufacturing a magnetic recording medium according to claim 3, wherein the magnetic recording medium is arranged so as to be inclined on a side opposite to a coating surface of the nonmagnetic support.
たのち、磁性粉の配向を行う請求項1ないし6のいずれ
かに記載の磁気記録媒体の製造方法。7. The method of manufacturing a magnetic recording medium according to claim 1, wherein the magnetic powder is oriented after an external magnetic field is applied by the unit magnet.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18344591A JP3207875B2 (en) | 1991-06-27 | 1991-06-27 | Manufacturing method of magnetic recording medium |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18344591A JP3207875B2 (en) | 1991-06-27 | 1991-06-27 | Manufacturing method of magnetic recording medium |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH056540A JPH056540A (en) | 1993-01-14 |
JP3207875B2 true JP3207875B2 (en) | 2001-09-10 |
Family
ID=16135899
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP18344591A Expired - Fee Related JP3207875B2 (en) | 1991-06-27 | 1991-06-27 | Manufacturing method of magnetic recording medium |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3207875B2 (en) |
-
1991
- 1991-06-27 JP JP18344591A patent/JP3207875B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
JPH056540A (en) | 1993-01-14 |
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