JPS60263321A - Magnetic recording medium - Google Patents

Magnetic recording medium

Info

Publication number
JPS60263321A
JPS60263321A JP59118783A JP11878384A JPS60263321A JP S60263321 A JPS60263321 A JP S60263321A JP 59118783 A JP59118783 A JP 59118783A JP 11878384 A JP11878384 A JP 11878384A JP S60263321 A JPS60263321 A JP S60263321A
Authority
JP
Japan
Prior art keywords
sorbic acid
magnetic
magnetic powder
powder
magnetic layer
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
Application number
JP59118783A
Other languages
Japanese (ja)
Inventor
Toshihiko Tanabe
田辺 敏彦
Takezo Shimizu
清水 丈三
Kosaburo Sato
佐藤 幸三郎
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Maxell Ltd
Original Assignee
Hitachi Maxell Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hitachi Maxell Ltd filed Critical Hitachi Maxell Ltd
Priority to JP59118783A priority Critical patent/JPS60263321A/en
Priority to KR1019850002155A priority patent/KR930000071B1/en
Priority to EP19850103972 priority patent/EP0157411B1/en
Priority to DE8585103972T priority patent/DE3572064D1/en
Priority to US06/719,807 priority patent/US4722863A/en
Publication of JPS60263321A publication Critical patent/JPS60263321A/en
Pending legal-status Critical Current

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  • Lubricants (AREA)
  • Paints Or Removers (AREA)
  • Magnetic Record Carriers (AREA)

Abstract

PURPOSE:To improve the dispersibility of magnetic powder and to improve the electromagnetic characteristic, wear resistance, etc. of a magnetic recording medium by providing a magnetic layer contg. the magnetic powder having a specific value or above of the specific surface area by a BET method and sorbic acid compd. selected from sorbic acid and the deriv. and salt thereof to said medium. CONSTITUTION:The magnetic layer contg. the fine magnetic powder having >=30m<2>/g specific surface area by the BET method and the sorbic acid compd. of >=1 kind selected from the sorbic acid, the deriv. thereof such as sorbic acid ester and sorbic acid amide and the metallic salt of Na, K, Ca, Al, Ti, etc. of the sorbic acid is formed on a substrate. The sorbic acid compd. is incorporated into the magnetic layer in such a manner that the entire weight thereof is within a 0.1-5pts.wt. range with respect to 100pts.wt. the magnetic powder. The dispersibility of the magnetic powder into the binder resin is thus improved and the magnetic recording medium which is free from output fluctuation, has high reproduced output and S/N ratio, has excellent wear resistance, etc. and good video characteristic and is suitable for high-density recording is thus obtd.

Description

【発明の詳細な説明】 〔技術分野および目的〕 この発明は、微細な磁性粉末を使用する磁気記録媒体に
関し、その目的とするところは、特に微細な磁性粉末の
分散性が良好で電気的特性に優れ、かつ耐摩耗性に優れ
た磁気記録媒体を提供することにある。
[Detailed Description of the Invention] [Technical Field and Objectives] The present invention relates to a magnetic recording medium using fine magnetic powder, and an object of the present invention is to have good dispersibility of the fine magnetic powder and to improve electrical properties. An object of the present invention is to provide a magnetic recording medium that has excellent wear resistance and wear resistance.

〔背景技術〕[Background technology]

近年、ビデオテープ等の磁気記録媒体においては、特に
、高密度記録化が進められているビデオテープレコーダ
等に対応して、鮮明な画質および明瞭な音質等を得るた
め、再生出力およびSN比等の改善がめられている。こ
のため、通常、磁性粉末、結合剤成分、有機溶剤および
その他の必要成分からなる磁性塗料をポリエステルフィ
ルムなどの基体上に塗布、乾燥してつくられる磁気記録
媒体に使用される磁性粉末の微粒子化が進められ、BE
T法による比表面積が30rr!/g以上の非常に微細
な磁性粉末を使用することが行われている。
In recent years, in magnetic recording media such as video tapes, playback output, SN ratio, etc. have been improved in order to obtain clear image quality and clear sound quality, especially in response to high-density recording such as video tape recorders. Improvements are expected. For this reason, the magnetic powder used in magnetic recording media is usually made into fine particles by applying a magnetic paint consisting of magnetic powder, a binder component, an organic solvent, and other necessary components onto a substrate such as a polyester film and drying it. is advanced and BE
Specific surface area by T method is 30rr! The use of very fine magnetic powder with a particle size of 1.2 g or more has been carried out.

ところが、この種の微細な磁性粉末は、通常表面が親水
性で、そのままでは親油性の結合剤樹脂中に良好に分散
することが難しい上、微細になるほど凝集し易く、また
磁性粉末の吸液量が大きくなり、磁性塗料の粘度が高く
なって分散機の剪断力効率低下を招くため、分散性が低
下し、再生出力およびSN比等を充分に向上させること
ができない。
However, this type of fine magnetic powder usually has a hydrophilic surface, and it is difficult to disperse it well in the lipophilic binder resin as it is. The amount increases, the viscosity of the magnetic coating material increases, and the shearing force efficiency of the dispersion machine decreases, resulting in a decrease in dispersibility, making it impossible to sufficiently improve reproduction output, signal-to-noise ratio, etc.

そこで、この種の磁性粉末の分散性を良好にするため、
分子の一端に親水基、他端に親油基を有する飽和もしく
は不飽和の脂肪酸などを分散剤として磁性塗料中に混入
させることが行われている(特公昭44−18221号
公報、特公昭58−9488号公報)が、これらの飽和
もしくは不飽和の脂肪酸は、磁性粉末との結合力が弱く
て、特に微細な磁性粉末の結合剤樹脂中における分散性
を未だ充分に改善することができず、微細な磁性粉末を
用いることによる再生出力およびSN比等の向上が充分
に図れない。その上、この種の微細な磁性粉末を使用し
て形成される磁性層は、磁気ヘッドと激しく摺接すると
磁性層に傷が入り易く、耐摩耗性が低下するため、一般
に、Cr2O3、Al2O3などの充填剤を磁性層中に
添加して耐摩耗性を改善することが行われているが、こ
れらの充填剤の分散性はこの種の磁性粉末よりもさらに
分散性が悪いため、これらの充填剤を充分に良好に分散
させることができず、磁性層の表面平滑性を良好にして
電磁変換特性を充分に向上させることが難しい。
Therefore, in order to improve the dispersibility of this type of magnetic powder,
Saturated or unsaturated fatty acids having a hydrophilic group at one end of the molecule and a lipophilic group at the other end are mixed into magnetic paints as a dispersant (Japanese Patent Publication No. 18221-1982, Japanese Patent Publication No. 18221-1989, However, these saturated or unsaturated fatty acids have a weak bonding force with magnetic powder, and it has not yet been possible to sufficiently improve the dispersibility of especially fine magnetic powder in binder resin. However, it is not possible to sufficiently improve reproduction output, signal-to-noise ratio, etc. by using fine magnetic powder. Furthermore, the magnetic layer formed using this type of fine magnetic powder is easily scratched when it comes into violent sliding contact with the magnetic head, reducing its wear resistance. Fillers have been added to the magnetic layer to improve wear resistance, but the dispersibility of these fillers is even worse than that of this type of magnetic powder. The agent cannot be dispersed sufficiently well, and it is difficult to improve the surface smoothness of the magnetic layer and sufficiently improve the electromagnetic conversion characteristics.

〔発明の概要〕[Summary of the invention]

f この発明は、かかる現状から、特にBET法による
比表面積が30%/g以上の微細な磁性粉末の結合剤樹
脂中への分散に有効で、Cr2O3、A1□03などの
充填剤等の分散も有効なものを見いだすべく、親油基と
親水基をともに有する化合物群について種々検討を行っ
た結果、驚くべきことに、ソルビン酸、ソルビン酸誘導
体およびソルビン酸金属塩が特に優れた分散能力を有す
ることがわかりなされたもので、ソルビン酸、ソルビン
酸誘導体、ソルビン酸金属塩から選ばれる少なくとも一
種以上のソルビン酸系化合物を、BET法による比表面
積が30r+(7g以上の微細な磁性粉末を含む磁性層
中に含有させることによって、この種の微細な磁性粉末
の結合剤樹脂中における分散性を充分に改善し、さらに
同時に使用される充填剤の分散性も改善して電磁変換特
性および耐摩耗性を充分に向上させたものである。
f In view of the current situation, this invention is particularly effective for dispersing fine magnetic powder with a specific surface area of 30%/g or more in a binder resin by the BET method, and is effective for dispersing fillers such as Cr2O3 and A1□03. As a result of conducting various studies on compounds having both lipophilic and hydrophilic groups, we surprisingly found that sorbic acid, sorbic acid derivatives, and sorbic acid metal salts have particularly excellent dispersion ability. At least one sorbic acid-based compound selected from sorbic acid, sorbic acid derivatives, and sorbic acid metal salts has a specific surface area of 30r+ (including fine magnetic powder of 7 g or more) as determined by the BET method. By incorporating it into the magnetic layer, the dispersibility of this type of fine magnetic powder in the binder resin is sufficiently improved, and the dispersibility of the filler used at the same time is also improved, resulting in improved electromagnetic characteristics and wear resistance. It has sufficiently improved characteristics.

かかるソルビン酸、ソルビン酸誘導体およびソルビン酸
金属塩が如何なる理由により、格段の分散能力を有する
かについては、未だ明確には解明されていないが、その
固有の化学構造につき考察すると、■分子中に共役二重
結合を有することにより、電子密度が分子内で局在し、
分極率が高まるために官能性が高められること、しかも
、■二重結合がともにトランスの(トランス−トランス
)構造を有することにより、官能基が分子の最外端側に
位置することとなり統計的、幾何学的に該分散剤表面部
に官能基が偏在し易くなること、および、■ソルビン酸
およびソルビン酸金属塩で炭素数6個、ソルビン酸誘導
体でも通常12個以下であり、このため適度の融点を有
することにより、良好な流動性を塗料に与えるため結合
剤樹脂中に混じりやすいこと、の3点が推定される。
The reason why sorbic acid, sorbic acid derivatives, and sorbic acid metal salts have such remarkable dispersion ability has not yet been clearly elucidated, but considering their unique chemical structure, By having a conjugated double bond, the electron density is localized within the molecule,
Functionality is increased due to increased polarizability, and ■Double bonds both have a trans (trans-trans) structure, so the functional group is located at the outermost end of the molecule, resulting in statistical , Geometrically, the functional groups tend to be unevenly distributed on the surface of the dispersant, and 2) sorbic acid and sorbic acid metal salts have 6 carbon atoms, and sorbic acid derivatives usually have 12 or less carbon atoms; It is presumed that the melting point is 3, which makes it easy to mix into the binder resin in order to impart good fluidity to the paint.

この発明において使用されるソルビン酸は、化学式CH
3CH=CHCH=C,HCOOHで表される化合物で
、分子中に共役二重結合を有し、この二重結合がともに
トランスで、分子量が比較的小さく、磁性粉末表面に良
好に被着し、また結合剤樹脂とのなじみもよい。従って
、このソルビン酸が磁性層中に含有されると、BET法
による比表面積が30rrr/g以上の微細な磁性粉末
の結合剤樹脂中における分散性が充分に改善され、同時
に磁性層中に含有される充填剤の分散性も改善されて、
再生出力およびSN比が充分に向上され、電磁変換特性
に優れるとともに耐摩耗性に優れた磁気記録媒体が得ら
れる。
The sorbic acid used in this invention has the chemical formula CH
A compound represented by 3CH=CHCH=C, HCOOH, which has a conjugated double bond in the molecule, both of which are trans, has a relatively small molecular weight, and adheres well to the surface of magnetic powder. It also has good compatibility with the binder resin. Therefore, when this sorbic acid is contained in the magnetic layer, the dispersibility of fine magnetic powder with a specific surface area of 30 rrr/g or more by the BET method in the binder resin is sufficiently improved, and at the same time, the sorbic acid contained in the magnetic layer is The dispersibility of the filler is also improved,
A magnetic recording medium with sufficiently improved reproduction output and S/N ratio, excellent electromagnetic conversion characteristics, and excellent wear resistance can be obtained.

また、この発明において使用されるソルビン酸誘導体と
しては、たとえば、ソルビン酸のメチルエステルC3H
2COocH3、エチルエステルC5H7COOC2H
5、プロピルエステJL/C3H2COOC3H2、ブ
チルエステルc5H7c00C4H,,7ミドC5H,
CONH2、ニトリJl/C5H,CN、7ニリドC5
H,C0NHCfIH5、フェニルヒドラジドc5H,
C0NHNHC,I(、等が好適なものとして挙げられ
、これらのソルビン酸誘導体も、前記のソルビン酸と同
様に、分子中に共役二重結合を有し、この二重結合がと
もにトランスで、分子量が比較的小さく、磁性粉末表面
に良好に被着し、また結合剤樹脂とのなじみもよい。従
って、これらのソルビン酸誘導体を磁性層中に含有させ
た場合も前記のソルビン酸を使用した場合と同様な効果
が得られ、BET法による比表面積が30m/g以上の
微細な磁性粉末の結合剤樹脂中における分散性が充分に
改善され、同時に磁性層中に含有される充填剤の分散性
も改善されて、再生出力およびSN比が充分に向上され
、電磁変換特性に優れるとともに耐摩耗性に優れた磁気
記録媒体が得られる。
Further, as the sorbic acid derivative used in this invention, for example, methyl ester of sorbic acid C3H
2COocH3, ethyl ester C5H7COOC2H
5, propyl ester JL/C3H2COOC3H2, butyl ester c5H7c00C4H,, 7 mido C5H,
CONH2, Nitori Jl/C5H, CN, 7 Nilide C5
H, CONHCfIH5, phenylhydrazide c5H,
C0NHNHC,I(, etc. are mentioned as suitable ones, and like the above-mentioned sorbic acid, these sorbic acid derivatives also have a conjugated double bond in the molecule, both of these double bonds are trans, and the molecular weight is is relatively small, adheres well to the surface of the magnetic powder, and has good compatibility with the binder resin.Therefore, when these sorbic acid derivatives are included in the magnetic layer, the above-mentioned sorbic acid is also used. The same effect is obtained, and the dispersibility of fine magnetic powder with a specific surface area of 30 m/g or more by the BET method in the binder resin is sufficiently improved, and at the same time, the dispersibility of the filler contained in the magnetic layer is improved. It is possible to obtain a magnetic recording medium with improved reproduction output and S/N ratio, excellent electromagnetic conversion characteristics, and excellent abrasion resistance.

さらに、この発明において使用されるソルビン酸金属塩
は、一般式 %式% (但し、Mは金属である。) で表される化合物で、前記のソルビン酸およびソルビン
酸誘導体と同様に、分子中に共役二重結合を有し、この
二重結合がともにトランスで、分子量が比較的小さく、
磁性粉末表面に良好に被着し、また結合剤樹脂とのなじ
みもよい。従って、これらのソルビン酸金属塩を磁性層
中に含有させた場合も前記のソルビン酸およびソルビン
酸誘導体を使用した場合と同様な効果が得られ、BET
法f による比表面積が30rd/g以上の微細な磁性
粉末の結合剤樹脂中における分散性が充分に改善され、
同時に磁性層中に含有される充填剤の分散性も改善され
て、再生出力およびSN比が充分に向上され、電磁変換
特性に優れるとともに耐摩耗性に優れた磁気記録媒体が
得られる。このようなソルビン酸金属塩の具体例として
は、たとえば、ソルビン酸のナトリウム塩、カリウム塩
、リチウム塩、銅塩、マグネシウム塩、カルシウム塩、
ストロンチウム塩、バリウム塩、亜鉛塩、カドミウム塩
、アルミニウム塩、スズ塩、鉛塩、チタン塩、ジルコニ
ウム塩等が挙げられ、いずれも好適に使用される。
Further, the sorbic acid metal salt used in the present invention is a compound represented by the general formula % (where M is a metal), and has a similar structure in the molecule as the sorbic acid and sorbic acid derivatives described above. It has a conjugated double bond, both of these double bonds are trans, and its molecular weight is relatively small.
It adheres well to the surface of the magnetic powder and is compatible with the binder resin. Therefore, when these sorbic acid metal salts are contained in the magnetic layer, the same effect as when using the above-mentioned sorbic acid and sorbic acid derivatives can be obtained, and the BET
The dispersibility of fine magnetic powder with a specific surface area of 30rd/g or more in the binder resin by method f is sufficiently improved,
At the same time, the dispersibility of the filler contained in the magnetic layer is improved, the reproduction output and the S/N ratio are sufficiently improved, and a magnetic recording medium with excellent electromagnetic conversion characteristics and excellent wear resistance is obtained. Specific examples of such metal sorbic acid salts include sodium salt, potassium salt, lithium salt, copper salt, magnesium salt, calcium salt,
Examples include strontium salts, barium salts, zinc salts, cadmium salts, aluminum salts, tin salts, lead salts, titanium salts, and zirconium salts, all of which are preferably used.

このようなソルビン酸またはソルビン酸誘導体もしくは
ソルビン酸金属塩は、これらを磁性塗料調製時に直接添
加するか、またはこれらをアルコール、エーテル等の適
当な溶剤に溶解させ、この溶解によって得られた溶液を
磁性塗料の調製時に添加するか、あるいはこの溶液中に
磁性粉末を浸漬して、予め磁性粉末の表面処理を行い、
この磁性粉末を使用して磁性塗料を開裂し、これを基体
上に塗布、乾燥するなどの方法で磁性層中に含有される
。特にソルビン酸金属塩は、水溶性で水に容易に溶解す
るため、このソルビン酸金属塩の水溶液中に磁性粉末を
浸漬すれば、極めて容易に磁性粉末の表面処理を行うこ
とができ、有機溶剤中に浸漬させる場合のように危険性
を伴うこともない。また通常水溶液中で製造される磁性
粉末を、水洗後、直ちにこのソルビン酸金属塩水溶液中
で表面処理することもでき、磁性粉末のソルビン酸金属
塩による表面処理が容易かつ迅速に行える。
Such sorbic acid, sorbic acid derivatives, or sorbic acid metal salts can be added directly when preparing magnetic paints, or dissolved in a suitable solvent such as alcohol or ether, and the solution obtained by this dissolution can be added. Add it when preparing the magnetic paint, or immerse the magnetic powder in this solution to pre-treat the surface of the magnetic powder.
This magnetic powder is used to cleave the magnetic paint, and it is incorporated into the magnetic layer by applying it onto a substrate and drying it. In particular, sorbate metal salts are water-soluble and easily dissolve in water, so if magnetic powder is immersed in an aqueous solution of sorbate metal salts, the surface treatment of the magnetic powder can be carried out extremely easily. There is no danger associated with immersion. Furthermore, magnetic powder that is normally produced in an aqueous solution can be surface-treated in this metal sorbate salt aqueous solution immediately after washing with water, and the surface treatment of the magnetic powder with the metal sorbate can be easily and quickly performed.

このようなソルビン酸またはソルビン酸誘導体もしくは
ソルビン酸金属塩の磁性層中での含有量は、磁性層中の
磁性粉末に対して0.1〜5重量%の範囲内で含有させ
るのが好ましく、少なすぎると所期の効果が得られず、
多すぎるとブリードアウトするおそれがある。
The content of such sorbic acid, sorbic acid derivative, or sorbic acid metal salt in the magnetic layer is preferably within the range of 0.1 to 5% by weight based on the magnetic powder in the magnetic layer. If it is too small, the desired effect will not be obtained,
If there is too much, there is a risk of bleed-out.

このようにして磁性層中に含有されるソルビン酸、ソル
ビン酸誘導体およびソルビン酸金属塩は、いずれか一種
を単独で使用してもよいが二種以上を併用してもよく、
また他の分散剤、例えば、0 飽和脂肪酸類、不飽和脂肪酸類、リン酸エステル類、レ
シチン、金属石鹸類等と併用してもよい。
Sorbic acid, sorbic acid derivatives, and sorbic acid metal salts contained in the magnetic layer may be used alone or in combination of two or more.
It may also be used in combination with other dispersants, such as saturated fatty acids, unsaturated fatty acids, phosphoric acid esters, lecithin, metal soaps, etc.

この発明に使用するBET法による比表面積が30%/
g以上の微細な磁性粉末としては、たとえば、r−Fe
203粉末、Fe5Q4粉末、γ−Fe203粉末とF
e3O4粉末の中間化合物粉末、Co含有r−Fe20
3粉末、Co含有Fe3O4粉末、CrO2粉末、(x
−Fe粉末、CO粉末、Fe−Ni粉末、Fe4N粉末
、バリウムフェライト粉末など従来公知のBET法によ
る比表面積が30i/g以上の微細な各種磁性粉末が広
く包含される。
The specific surface area according to the BET method used in this invention is 30%/
For example, r-Fe
203 powder, Fe5Q4 powder, γ-Fe203 powder and F
Intermediate compound powder of e3O4 powder, Co-containing r-Fe20
3 powder, Co-containing Fe3O4 powder, CrO2 powder, (x
Various fine magnetic powders having a specific surface area of 30 i/g or more by the conventionally known BET method, such as -Fe powder, CO powder, Fe--Ni powder, Fe4N powder, and barium ferrite powder, are widely included.

また、結合剤樹脂としては、塩化ビニル−酢酸ビニル系
共重合体、繊維素系樹脂、ブチラール系樹脂、ポリウレ
タン系樹脂、ポリエステル系樹脂、エポキシ系樹脂、ポ
リエーテル系樹脂、イソシアネート化合物など従来から
汎用されている結合剤樹脂がいずれも用いられる。
In addition, conventional binder resins include vinyl chloride-vinyl acetate copolymers, cellulose resins, butyral resins, polyurethane resins, polyester resins, epoxy resins, polyether resins, and isocyanate compounds. Any of the binder resins listed above can be used.

有機溶剤としては、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などのケ11 トン系溶剤、酢酸エチル、酢酸ブチルなどのエステル系
溶剤、ベンゼン、トルエン、キシレンなどの芳香族炭化
水素系溶剤、テトラヒドロフラン、ジオキサンなどのエ
ーテル系溶剤など、使用する結合剤樹脂を熔解するのに
適した溶剤が、特に制限されることなく単独または二種
以上混合して使用される。
Examples of organic solvents include ketone solvents such as cyclohexanone, methyl ethyl ketone, and methyl isobutyl ketone, ester solvents such as ethyl acetate and butyl acetate, aromatic hydrocarbon solvents such as benzene, toluene, and xylene, and tetrahydrofuran and dioxane. Solvents suitable for melting the binder resin to be used, such as ether solvents, may be used alone or in a mixture of two or more without particular limitation.

なお、磁性塗料中には通常使用されている各種添加剤、
たとえば、潤滑剤、研磨剤、帯電防止剤などを適宜に添
加使用してもよい。
In addition, various additives commonly used in magnetic paints,
For example, a lubricant, an abrasive, an antistatic agent, etc. may be added as appropriate.

また、磁気テープ等の磁気記録媒体の磁性層と反対側の
背面には、必要に応じてバンクコート層を設けてもよい
Further, a bank coat layer may be provided on the back side of the magnetic recording medium such as a magnetic tape, which is opposite to the magnetic layer, if necessary.

〔実施例〕〔Example〕

次に、この発明の実施例について説明する。 Next, embodiments of the invention will be described.

実施例1 Co含有rFe2O3粉末 100重量部(BET法に
よる比表面積 40rrr/g) i ニトロセルロース(H1/2夕 56〃イブ、16
%溶液) カーボンブランク(平均粒子径 4.5〃23mμ) cx−Fe203(粒状、平均粒 5.0〃子径1.0
μ) Cr203(平均粒子径1.O#) 0.8 //A1
203(平均粒子径0.4μ)2.0〃ステアリン酸亜
鉛 0.5〃 シクロへキサノン 90〃 トルエン 90〃 この組成物を高速攪拌機で2〜5時間時間分散した後、
ソルビン酸を2.0重量部添加し、その後サンドミルで
混合分散した。次いで、これにポリウレタン樹脂(20
%溶液)40重量部三官能性低分子量イソシアネ−4〃 ト化合物(75%溶液) ステアリン酸−n−ブチル 1 〃 ミリスチン酸 2 〃 シクロへキサノン 40〃 トルエン 40〃 3 を適宜の順序で加え、高速攪拌機で混合分散したのち、
1μのフィルターを通過させて磁性塗料を開裂した。こ
の磁性塗料を厚さ13μのポリエステルフィルム上に乾
燥厚が約5μとなるように塗布、乾燥し、カレンダー処
理を行ったのち、所定の巾に裁断してビデオテープをつ
くった。
Example 1 Co-containing rFe2O3 powder 100 parts by weight (specific surface area 40 rrr/g by BET method) i Nitrocellulose (H1/2 Eve, 16
% solution) Carbon blank (average particle size 4.5〃23mμ) cx-Fe203 (granular, average particle size 5.0〃particle diameter 1.0
μ) Cr203 (average particle size 1.O#) 0.8 //A1
203 (average particle size 0.4 μ) 2.0 Zinc stearate 0.5 Cyclohexanone 90 Toluene 90 After dispersing this composition with a high-speed stirrer for 2 to 5 hours,
2.0 parts by weight of sorbic acid was added, and then mixed and dispersed using a sand mill. Next, polyurethane resin (20
% solution) 40 parts by weight trifunctional low molecular weight isocyanate compound (75% solution) n-butyl stearate 1 myristic acid 2 cyclohexanone 40 toluene 40 3 were added in the appropriate order, After mixing and dispersing with a high-speed stirrer,
The magnetic paint was cleaved by passing it through a 1μ filter. This magnetic paint was applied onto a 13 μm thick polyester film to a dry thickness of approximately 5 μm, dried, calendered, and then cut to a predetermined width to make a videotape.

実施例2 実施例1における磁性塗料の調製において、ソルビン酸
の使用量を2.0重量部から0.5重量部に変更した以
外は実施例1と同様にしてビデオテープをつくった。
Example 2 A videotape was produced in the same manner as in Example 1, except that the amount of sorbic acid used in the preparation of the magnetic coating material in Example 1 was changed from 2.0 parts by weight to 0.5 parts by weight.

実施例3 実施例1における磁性塗料の調製において、ソルビン酸
の使用量を2.0重量部から5.0重量部に変更した以
外は実施例1と同様にしてビデオテープをつくった。
Example 3 A videotape was made in the same manner as in Example 1, except that the amount of sorbic acid used in the preparation of the magnetic paint was changed from 2.0 parts by weight to 5.0 parts by weight.

実施例4 実施例1における磁性塗料の調製において、ソルビン酸
に代えて、ソルビン酸−n−ブチルを同量使用した以外
は実施例1と同様にしてビデオテ4 一プをつくった。
Example 4 Videotape 4 was prepared in the same manner as in Example 1, except that the same amount of n-butyl sorbate was used in place of sorbic acid in the preparation of the magnetic paint in Example 1.

実施例5 実施例1における磁性塗料の調製において、ソルビン酸
に代えて、ソルビン酸カリウムを同量使用した以外は実
施例1と同様にしてビデオテープをつくった。
Example 5 A videotape was made in the same manner as in Example 1, except that in the preparation of the magnetic paint in Example 1, the same amount of potassium sorbate was used instead of sorbic acid.

実施例6 実施例1における磁性塗料の調製において、ニトロセル
ロースに代えて、塩化ビニル−酢酸ヒニルービニルアル
コール共重合体(20%溶液)ヲ50重量部使用し、ポ
リウレタン樹脂の使用量を40重量部から35重量部に
変更した以外は、実施例1と同様にしてビデオテープを
つくった。
Example 6 In the preparation of the magnetic paint in Example 1, 50 parts by weight of vinyl chloride-vinyl acetate-vinyl alcohol copolymer (20% solution) was used in place of nitrocellulose, and the amount of polyurethane resin used was 40 parts by weight. A videotape was made in the same manner as in Example 1, except that the amount was changed from 1 part to 35 parts by weight.

比較例1 実施例1における磁性塗料の調製において、ソルビン酸
を省いた以外は実施例1と同様にしてビデオテープをつ
くった。
Comparative Example 1 A videotape was made in the same manner as in Example 1 except that sorbic acid was omitted in the preparation of the magnetic paint in Example 1.

比較例2 実施例1における磁性塗料の調製において、ソルビン酸
に代えてラウリン酸を同量使用した以外15 は実施例1と同様にしてビデオテープをつくった。
Comparative Example 2 A videotape was produced in the same manner as in Example 1, except that the same amount of lauric acid was used in place of sorbic acid in the preparation of the magnetic paint in Example 1.

各実施例および各比較例で得られた各磁気テープについ
て、磁性層の表面粗さ、RF比出力クロマ出力、ビデオ
SN比、カラーSN比、スチル特性およびヘッド摩耗量
を下記の方法で試験した。
For each magnetic tape obtained in each Example and each Comparative Example, the surface roughness of the magnetic layer, RF specific output chroma output, video SN ratio, color SN ratio, still characteristics, and head wear amount were tested using the following methods. .

〈磁性層の表面粗さ〉 触針式表面粗度計を用いてビデオテープの中心線平均粗
さくRa)を算出した。
<Surface Roughness of Magnetic Layer> The center line average roughness (Ra) of the videotape was calculated using a stylus type surface roughness meter.

<RF比出力 VH3方式のVTRを用い、ビデオテープに50%ホワ
イトのビデオ信号を記録再生し、そのFF変調再生信号
のレベルをオシロスコープを用いて測定し、基準テープ
との相対値で示した。
<RF ratio output A 50% white video signal was recorded and reproduced on a video tape using a VH3 type VTR, and the level of the FF modulated reproduction signal was measured using an oscilloscope and expressed as a relative value with respect to the reference tape.

〈クロマ出力〉 VH3方式のVTRを用い、ビデオテープに一色クロマ
信号を記録再生し、その低域変換色信号の再生信号のレ
ベルをオシロスコープを用いて測定し、基準テープとの
相対値で示した。
<Chroma output> A VH3 system VTR was used to record and play back a single color chroma signal on a videotape, and the level of the playback signal of the low frequency converted color signal was measured using an oscilloscope and expressed as a relative value with respect to the reference tape. .

〈ビデオSN比〉 、 VH3方式のVTRを用い、ビデオテープに50%
ホワイトのビデオ信号を記録再生し、カラービデオノイ
ズ測定器によりその再生信号のノイズを測定し、SN比
を算出して基準テープとの相対値で示した。
<Video SN ratio>: 50% on videotape using VH3 system VTR
A white video signal was recorded and reproduced, the noise of the reproduced signal was measured using a color video noise measuring device, and the SN ratio was calculated and expressed as a relative value with respect to the reference tape.

〈カラーSN比〉 VH3方式のVTRを用い、ビデオテープに一色クロマ
信号を記録再生し、カラービデオノイズ測定器によりそ
の再生信号のAMノイズを測定し、SN比を算出して基
準テープとの相対値で示した。
<Color SN ratio> Using a VH3 system VTR, record and play back a one-color chroma signal on a videotape, measure the AM noise of the playback signal with a color video noise measuring device, calculate the SN ratio, and compare it with the reference tape. Shown as a value.

くスチル特性〉 VH3方式のVTRを用い、ビデオテープをスチルモー
ドで再生し、その再生出力レベルが初期値から5dB低
下するまでの時間を測定した。
Still Characteristics Using a VH3 VTR, a videotape was played back in still mode, and the time required for the playback output level to drop by 5 dB from the initial value was measured.

〈ヘッド摩耗量〉 40℃、80%RHの環境下で、VH3方式のVTRを
用いてビデオテープを100回走行させ、その後、ビデ
オヘッドのヘッド摩耗量を測定した。
<Head wear amount> A video tape was run 100 times using a VH3 type VTR in an environment of 40° C. and 80% RH, and then the head wear amount of the video head was measured.

下表はその結果である。The table below shows the results.

18 (発明の効果〕 上表から明らかなように、この発明で得られた磁気テー
プ(実施例1〜6)は、従来の磁気テープ(比較例1お
よび2)に比べて、磁性層の表面粗さが小さく、RF出
力、クロマ出力、ビデオSN比およびカラーSN比が高
くてスチル特性時間が長く、さらにヘッド摩耗量が少な
く、このことからこの発明によって得られる磁気記録媒
体は、磁性粉末の分散性が良好で、磁性層の表面平滑性
がよく、高出力、高SN比で電磁変換特性に優れ、かつ
耐摩耗性に優れていることがわかる。
18 (Effects of the Invention) As is clear from the above table, the magnetic tapes obtained by the present invention (Examples 1 to 6) have a higher surface area of the magnetic layer than conventional magnetic tapes (Comparative Examples 1 and 2). The magnetic recording medium obtained by the present invention has small roughness, high RF output, chroma output, video SN ratio, and color SN ratio, long still characteristic time, and low head wear. It can be seen that it has good dispersibility, good surface smoothness of the magnetic layer, high output, high S/N ratio, excellent electromagnetic conversion characteristics, and excellent wear resistance.

特許出願人 日立マクセル株式会社Patent applicant: Hitachi Maxell, Ltd.

Claims (1)

【特許請求の範囲】[Claims] 1、BET法による比表面積が30rrf/g以上の磁
性粉末と、ソルビン酸、ソルビン酸誘導体、ソルビン酸
金属塩から選ばれる少なくとも一種以上のソルビン酸系
化合物とが含まれてなる磁性層を有する磁気記録媒体
1. A magnetic material having a magnetic layer containing magnetic powder having a specific surface area of 30 rrf/g or more by the BET method and at least one sorbic acid compound selected from sorbic acid, sorbic acid derivatives, and sorbic acid metal salts. recoding media
JP59118783A 1984-04-04 1984-06-09 Magnetic recording medium Pending JPS60263321A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
JP59118783A JPS60263321A (en) 1984-06-09 1984-06-09 Magnetic recording medium
KR1019850002155A KR930000071B1 (en) 1984-04-04 1985-03-30 Megnetic medium
EP19850103972 EP0157411B1 (en) 1984-04-04 1985-04-02 Magnetic recording medium
DE8585103972T DE3572064D1 (en) 1984-04-04 1985-04-02 Magnetic recording medium
US06/719,807 US4722863A (en) 1984-04-04 1985-04-04 Magnetic recording medium

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP59118783A JPS60263321A (en) 1984-06-09 1984-06-09 Magnetic recording medium

Publications (1)

Publication Number Publication Date
JPS60263321A true JPS60263321A (en) 1985-12-26

Family

ID=14744973

Family Applications (1)

Application Number Title Priority Date Filing Date
JP59118783A Pending JPS60263321A (en) 1984-04-04 1984-06-09 Magnetic recording medium

Country Status (1)

Country Link
JP (1) JPS60263321A (en)

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