JPS62132230A - Magnetic recording medium - Google Patents
Magnetic recording mediumInfo
- Publication number
- JPS62132230A JPS62132230A JP27137485A JP27137485A JPS62132230A JP S62132230 A JPS62132230 A JP S62132230A JP 27137485 A JP27137485 A JP 27137485A JP 27137485 A JP27137485 A JP 27137485A JP S62132230 A JPS62132230 A JP S62132230A
- Authority
- JP
- Japan
- Prior art keywords
- particles
- bet value
- magnetic
- recording medium
- cro2
- 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.)
- Granted
Links
Landscapes
- Magnetic Record Carriers (AREA)
- Paints Or Removers (AREA)
Abstract
Description
【発明の詳細な説明】
〔技術分野〕
本発明は磁気記録媒体、特にビデオテープ等の高密度記
録に適した磁気記録媒体に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a magnetic recording medium, and particularly to a magnetic recording medium suitable for high-density recording such as video tape.
近年、磁気記録媒体の発展は目ざましく、オーディオテ
ープ、ビデオテープ、フロッピーディスク壜どが広く使
用されている。特に最近は、家庭用ビデオ機器が急速に
普及し、ビデオテープの伸びが著るしい。それに伴ない
、ビデオテープに要求される特性も、年々、きびしくな
ってきている。In recent years, the development of magnetic recording media has been remarkable, and audio tapes, video tapes, floppy disks, etc. are widely used. Particularly recently, home video equipment has become rapidly popular, and the growth of video tapes has been remarkable. Along with this, the characteristics required of videotapes are becoming stricter year by year.
例えば、高画質、高耐久性がますます求められ、技術的
検討が進められている。高画質ビデオテープ用磁性材と
しては、低ノイズを目的として、粒子サイズの小さい強
磁性材が使われる傾向にあるが、近年、微粒子の磁性粉
を使用することにより、ビデオS/Nは、飛躍的に改善
され、使用者の要求に応えている。For example, high image quality and high durability are increasingly required, and technical studies are underway. Ferromagnetic materials with small particle sizes tend to be used as magnetic materials for high-quality videotapes for the purpose of low noise, but in recent years, the use of fine magnetic powder particles has dramatically improved video S/N. has been improved to meet the needs of users.
高画質ビデオテープ用磁性材としては現在C。Currently, C is the preferred magnetic material for high-quality videotapes.
被着Ml r −F at Os粒子を代表するCo含
含有−Few Os (Co−γ−Fed OH)が広
く用いられている。この磁性材は分散性が良く高域特性
がすぐれているが、微粒子化に伴ない、問題点も生じて
きた。第一点は、微粒子化に伴ない、樹脂バインダー中
への磁性材の分散が難かしくなり、磁性塗膜中に、磁性
粒子が、詰まりにくくなる点である。そのため、テープ
磁気特性の1つである、最大残留磁束密8度Brが低下
し、オーディオ感度、クロマ出力等の低域特性が低下し
て、重要な特性である、C−8/Nが低下する。第2点
は、微粒子化に伴カい、磁性塗膜の光透過率が低下する
点である。VH8・ビデオデツキにおいては、テープエ
ンドを光の透過量で検知する。走行中の誤動作防止の為
、テープの光透過量を少なくする必要がある。その対策
として、カーボン等非磁性、無機着色顔料粒子を増加す
る必要があり、その面からも、電磁変換特性が不利にな
る。Co-containing -Few Os (Co-γ-Fed OH), which represents deposited Ml r -F at Os particles, is widely used. Although this magnetic material has good dispersibility and excellent high-frequency characteristics, problems have arisen as the particles have become finer. The first point is that as the particles become finer, it becomes difficult to disperse the magnetic material into the resin binder, and the magnetic coating film becomes less likely to be clogged with magnetic particles. As a result, the maximum residual magnetic flux density, 8 degrees Br, which is one of the tape magnetic characteristics, decreases, the low-frequency characteristics such as audio sensitivity and chroma output decrease, and the important characteristic, C-8/N, decreases. do. The second point is that the light transmittance of the magnetic coating film decreases as the particles become finer. In VH8/video decks, the tape end is detected by the amount of light transmitted. To prevent malfunctions during running, it is necessary to reduce the amount of light transmitted through the tape. As a countermeasure, it is necessary to increase the amount of non-magnetic, inorganic colored pigment particles such as carbon, which also makes the electromagnetic conversion characteristics disadvantageous.
本発明者らは磁性粒子を、微粒子にした場合でも低域特
性のすぐれたビデオテープを作るべく検討した結果、良
好な特性を得る方法を発明した。The inventors of the present invention have studied how to make a videotape with excellent low-frequency characteristics even when the magnetic particles are made into fine particles, and as a result, they have invented a method for obtaining good characteristics.
本発明の目的は、電磁変換特性が良く、しかも光透過性
の低い磁気記録媒体、特にビデオテープ等の高密度記録
媒体を提供することにある。An object of the present invention is to provide a magnetic recording medium with good electromagnetic conversion characteristics and low optical transparency, particularly a high-density recording medium such as a video tape.
本発明による磁気記録媒体は、磁性粒子を樹脂バインダ
ー中に分散した磁性層を、ポリエステルフィルム等のプ
ラスチックベース上に形成してなるもので、強磁性粒子
として、BET値25 m”79以上のCo−γ−Fe
2O3粒子とBET値20 m”/ji以上のCrO2
粒子を、Co−γ−FelOg粒子に対して、5〜25
wt%添加したことを特徴とする。The magnetic recording medium according to the present invention is formed by forming a magnetic layer in which magnetic particles are dispersed in a resin binder on a plastic base such as a polyester film. -γ-Fe
2O3 particles and CrO2 with a BET value of 20 m”/ji or more
5 to 25 particles for Co-γ-FelOg particles.
It is characterized by adding wt%.
本発明の磁気記録媒体はCo−γ−FezO@粒子にC
rO!粒子を添加したため、残留磁束密度Brが向上し
、低域特性が改善される。また、透光性は黒色のCra
gを混合することKより、大幅に低下し、従来のような
カーボンブラックの使用は必要でなくなるか、最低限の
使用で済むことになる。The magnetic recording medium of the present invention contains C in Co-γ-FezO@ particles.
rO! Since the particles are added, the residual magnetic flux density Br is increased and the low frequency characteristics are improved. In addition, the translucency is black Cra
By mixing g, K is significantly lowered, and the conventional use of carbon black is no longer necessary or can be used at a minimum.
本発明は、Co−7−Fez Os 粒子を主たる成
分として用い、これにCrO2粒子を併用するものであ
る。In the present invention, Co-7-Fez Os particles are used as the main component, and CrO2 particles are also used in combination.
Co−γ−Fe2O3としては任意のCo含有型の粒子
を用いうるが、好ましくはCo被着製のものを用いる。Although any Co-containing type particles can be used as Co-γ-Fe2O3, particles coated with Co are preferably used.
高周波電磁変換特性の面からはCo−7−Fe2O2の
表面積はBET値で25 m” 79以上のものを用い
るべきである。一般にCo−γ−Fe20gの分散性は
良く、高域特性がすぐれているが、BET値が大きくな
ると低BET値のものより分散が難しくなり、磁性塗料
中に詰まりにくくなり、低域の出力の低下と光透過量の
増加を生じる。From the viewpoint of high-frequency electromagnetic conversion characteristics, the surface area of Co-7-Fe2O2 should be 25 m"79 or more in BET value. Generally, Co-7-Fe20g has good dispersibility and excellent high-frequency characteristics. However, when the BET value becomes large, it becomes more difficult to disperse than when the BET value is low, and it becomes less likely to be clogged in the magnetic paint, resulting in a decrease in low-frequency output and an increase in the amount of light transmission.
そこで、本発明ではBET値20m”/9 以上のCr
O2粒子をCo−γ−Felonを基準として約5〜2
5重畳チ磁性塗料中に共存させる。一般にCrO2はB
rが高く、低域の出力が高く、電気抵抗が低く、さらに
、粒子の色が黒色である為光透過量が少ないという利点
がある。使用するCrO!はBET値が20m”79以
上のものを用いるべきである。BET値が小さいと分散
性は良くなるが高域特性に悪影響が出る。BET値が2
0m”79以上の場合には、Cr01単独では分散し難
いが、その含有率を約25重量%以下に抑えることによ
り十分な分散性を得ることができる。またその含有率を
約5重量%以上にすると光の透過率が大幅に低下し、カ
ーボンブラックの使用が不要となるため、電磁特性が良
くなる。特に残留磁束密度、RF’低域特性、カラーS
/N比(C−8/N)、クロマ出力、オーディオ出力が
改善される。Therefore, in the present invention, Cr with a BET value of 20m"/9 or more
Approximately 5 to 2 O2 particles based on Co-γ-Felon
Coexist in the 5-layer magnetic paint. Generally CrO2 is B
It has the advantages of high r, high low-frequency output, low electrical resistance, and because the color of the particles is black, the amount of light transmitted is small. CrO to use! should be used with a BET value of 20m"79 or higher. If the BET value is small, the dispersion will be good, but the high frequency characteristics will be adversely affected.
0m"79 or more, it is difficult to disperse with Cr01 alone, but sufficient dispersibility can be obtained by suppressing the content to about 25% by weight or less. Also, if the content is about 5% by weight or more, sufficient dispersibility can be obtained. By doing so, the light transmittance decreases significantly and the use of carbon black becomes unnecessary, which improves electromagnetic properties.In particular, residual magnetic flux density, RF' low-frequency characteristics, and color S
/N ratio (C-8/N), chroma output, and audio output are improved.
本発明はこのようにCrO2粒子の分散性の悪さをCo
−γ−FelO1粒子と併用することで改善し、こうし
てCrO2粒子の長所を利用することによりCo−r−
Fe201粒子の短所を補ったものである。In this way, the present invention solves the poor dispersibility of CrO2 particles by
Co-r-
This compensates for the disadvantages of Fe201 particles.
下記組成比で材料を混合し、混合物を、ボールミルで充
分に分散したのち、ポリエステルフィルムに塗布し、サ
ンプルを作成した。Materials were mixed in the following composition ratio, and the mixture was sufficiently dispersed in a ball mill, and then applied to a polyester film to prepare a sample.
実施例1.2.5 (1) (2
) (31Co−7−Fewo、(BET30m”/
J9)95.85.75wt%Crow (
BET25m”/、ji+) 5.15.25wt%
カーボン ナシAlt Oh
5wt%塩ビ・酢ビ・共
重量体 1owt%ウレタン
10wtチ脂肪酸
3 チイソシアネート
51MEK 250 %
比較例1
Crys (BET25m”/、!i’)
100wt%カーボン ナシ
A1.0. 5
チ塩ビ・酢ビ・共重合体 10 チ
ウレタン 10 チ脂肪rR
3%
インシアネー) 5’%MEK
250 チ比較例2
Co−γ−FewOs (BET30m”/9)100
wt%カーボン 7 チ
At、0. 5 %
塩ビ・酢ビ・共重合体 10 チウレタン
10 チMEK
250 チイソシアネート
5 チ脂肪酸
3 チ本発明に使用する樹脂バインダーは、特
徴部分を構成するものではなく、従来より磁気記録媒体
に使用されている熱可塑性バインダー、熱硬化系バイン
ダー、電子線硬化系バインダー、紫外線硬化系バインダ
ーなどの、全ての樹脂バインダーが使用できる。特に、
塩化ビニール、酢酸ビニール共重合体を、ウレタン及び
インシアネートを樹脂成分とする、熱硬化系バインダー
が適している。Example 1.2.5 (1) (2
) (31Co-7-Fewo, (BET30m”/
J9) 95.85.75wt%Crow (
BET25m”/, ji+) 5.15.25wt%
Carbon None Alt Oh
5wt% vinyl chloride/vinyl acetate co-weight 1wt% urethane
10wt thi fatty acid
3 Thiisocyanate
51MEK 250%
Comparative example 1 Crys (BET25m"/,!i')
100wt% carbon without A1.0. 5
Thi PVC/Vinyl acetate/copolymer 10 Thiurethane 10 Thi fat rR
3% Incyane) 5'% MEK
250 Comparative Example 2 Co-γ-FewOs (BET30m”/9) 100
wt% carbon 7 At, 0. 5%
PVC/PVC acetate/copolymer 10 Thiurethane 10 ThiMEK
250 Thiisocyanate
5 Thi fatty acids
3. The resin binder used in the present invention does not constitute a characteristic part, and may be a thermoplastic binder, a thermosetting binder, an electron beam curing binder, an ultraviolet curing binder, etc. that have been conventionally used in magnetic recording media. All resin binders can be used. especially,
A thermosetting binder containing vinyl chloride, vinyl acetate copolymer, urethane and incyanate as resin components is suitable.
更に、磁性層の摩擦を低下させ、走行性を良好にする為
、潤滑剤として、炭素数12〜20の脂肪酸及び炭素数
3〜12の一価アルコールと前記脂肪酸とのエステルの
うち、どちらか一方あるいは双方の混合物を使用するこ
とができる。実施例tのサンプルをサンプルC−1、C
−2、C−5、比較例1のサンプルをサンプルA、比較
例2のサンプルをサンプルBとする。表IK各サンプル
の測定結果を示す。Furthermore, in order to reduce the friction of the magnetic layer and improve running properties, a lubricant selected from among fatty acids having 12 to 20 carbon atoms and esters of monohydric alcohols having 3 to 12 carbon atoms and the above-mentioned fatty acids is used. One or a mixture of both can be used. Samples C-1 and C of Example t
-2, C-5, Sample A is the sample of Comparative Example 1, and Sample B is the sample of Comparative Example 2. Table IK shows the measurement results for each sample.
〔本発明の作用効果、比較例との対比〕B E T 5
0 m”/11のCo−r−Fe2O2を使用した比較
例1のサンプルナAは、電気抵抗、光透過率の要求特性
を満たす為に、カーボンを7vt%添加している。C6
−4−Fe10gの、分散性の良さにより表面粗さR&
が良く、エンベロープが良いにもかかわらずBITが高
いため、Br値が低く、りμマー出力が低く、オーディ
オ感度C−8/Nが低い。[Operations and effects of the present invention, comparison with comparative examples] BET 5
Sample A of Comparative Example 1 using 0 m''/11 Cor-Fe2O2 has 7vt% of carbon added in order to meet the required characteristics of electrical resistance and light transmittance.C6
-4-Fe10g has good dispersibility, resulting in surface roughness R&
Despite the good envelope and high BIT, the Br value is low, the μmar output is low, and the audio sensitivity C-8/N is low.
一方、BET25m”/、li’のCr01を使用した
比較例2のサンプルBは、残留磁束密度Brが高く、ク
ロマ出力、オーディオ出力などの低域出力が高い。クロ
マ出力は、C−8/Nに影響し、クロマ出力の高いテー
プは、C−8/Nも高い値が得られる。しかし表から、
Cr01磁性粒子は分散性が悪い為に、テープ表面粗さ
Raが大きく、エンベロープが悪い。その影響でサンプ
ルBは、クロマ出力が高いというCry、粒子本来の特
徴を生かせずC−8/Nは低い値にとどまっている。On the other hand, Sample B of Comparative Example 2 using Cr01 with a BET of 25 m''/, li' has a high residual magnetic flux density Br and high low-frequency output such as chroma output and audio output.The chroma output is C-8/N A tape with a high chroma output will also have a high C-8/N value.However, from the table,
Since the Cr01 magnetic particles have poor dispersibility, the tape surface roughness Ra is large and the envelope is poor. As a result, Sample B cannot take advantage of the inherent characteristics of Cry particles, which have a high chroma output, and C-8/N remains at a low value.
このように、サンプルAとサンプルBは、一長一短があ
り、ビデオテープとしては、完全ではない。実施例1.
2.3のサンプルC−1、C−2、C−3は、B、E
T値25 m” /9のCragをBET値507B”
/iのCo−r−Fe電0@の粒子に対して5Wtc
s・15wt1%・25wt(i の割り合いで混合し
、ビデオテープとしたサンプルである。サンプルAとサ
ンプルBの長所を兼ね備えていることがわかる。すなわ
ち、Cr01を混合することにより、カーボンを使用せ
ずに、電気抵抗を下げることができ、光透過率を満足す
ることができる。さらに、Brが大きく、クロマ−出力
が高い。又、Co−γ−FelO1本来の分散性の良さ
を失なっていない為テープ表面が平滑で、エンベロープ
が良(、C−8/Nが高い。このようにサンプルC−1
、C−2、C−3は、ビデオテープとして、バランスの
とれたすぐれた特性を示しており、今後さらに進む、ビ
デオテープの高画質化に対して有効な手段になり得る方
策である。In this way, Sample A and Sample B have advantages and disadvantages, and are not perfect as video tapes. Example 1.
Samples C-1, C-2, and C-3 in 2.3 are B, E
BET value 507B for Crag with T value 25 m”/9
5Wtc for /i Cor-Fe electron 0@particles
This sample was made into a videotape by mixing s・15wt1%・25wt (i).It can be seen that it has both the advantages of sample A and sample B.In other words, by mixing Cr01, it is possible to use carbon. The electrical resistance can be lowered and the optical transmittance can be satisfied without the need for oxidation.Furthermore, Br is large and the chromer output is high.Also, the original good dispersibility of Co-γ-FelO1 is not lost. The tape surface is smooth and the envelope is good (and C-8/N is high. In this way, sample C-1
, C-2, and C-3 exhibit well-balanced and excellent characteristics as video tapes, and are a measure that can be an effective means for further improving the image quality of video tapes in the future.
手続h11正書
昭和61年9月22日
1°、1許庁長官黒田明雄殿
事件の表示 昭和60年特 願第271374 号発明
の名称 磁気記録媒体
補正をする者Procedure h11 Official Book September 22, 1986 1°, 1 Indication of the case of Mr. Akio Kuroda, Commissioner of the License Agency 1985 Patent Application No. 271374 Title of the invention Person who corrects magnetic recording media
Claims (1)
塗料を、プラスチックベース上に塗布した、磁気記録媒
体において、上記強磁性粒子が、BET値25m^2/
g以上のCo−γ−Fe_2O_3粒子とBET値25
m^2/g以上のCrO_2粒子とからなり、CrO_
2粒子が、Co−γ−Fe_2O_3粒子に対して5w
t%以上、25wt%以下含まれることを特徴とする、
磁気記録媒体。1. In a magnetic recording medium in which a magnetic paint in which ferromagnetic particles are dispersed in a resin binder is coated on a plastic base, the ferromagnetic particles have a BET value of 25 m^2/
Co-γ-Fe_2O_3 particles larger than g and BET value 25
It consists of CrO_2 particles of m^2/g or more, and CrO_
2 particles is 5w for Co-γ-Fe_2O_3 particles
characterized by containing t% or more and 25wt% or less,
magnetic recording medium.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP60271374A JPH0746418B2 (en) | 1985-12-04 | 1985-12-04 | Magnetic recording medium |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP60271374A JPH0746418B2 (en) | 1985-12-04 | 1985-12-04 | Magnetic recording medium |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS62132230A true JPS62132230A (en) | 1987-06-15 |
JPH0746418B2 JPH0746418B2 (en) | 1995-05-17 |
Family
ID=17499179
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP60271374A Expired - Lifetime JPH0746418B2 (en) | 1985-12-04 | 1985-12-04 | Magnetic recording medium |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0746418B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04184903A (en) * | 1990-11-19 | 1992-07-01 | Toda Kogyo Corp | Manufacture of magnetic particle power for magnetic recording |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61919A (en) * | 1984-06-13 | 1986-01-06 | Hitachi Maxell Ltd | Magnetic recording medium |
-
1985
- 1985-12-04 JP JP60271374A patent/JPH0746418B2/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61919A (en) * | 1984-06-13 | 1986-01-06 | Hitachi Maxell Ltd | Magnetic recording medium |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04184903A (en) * | 1990-11-19 | 1992-07-01 | Toda Kogyo Corp | Manufacture of magnetic particle power for magnetic recording |
Also Published As
Publication number | Publication date |
---|---|
JPH0746418B2 (en) | 1995-05-17 |
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