JPH02260223A - Magnetic recording medium - Google Patents
Magnetic recording mediumInfo
- Publication number
- JPH02260223A JPH02260223A JP8194689A JP8194689A JPH02260223A JP H02260223 A JPH02260223 A JP H02260223A JP 8194689 A JP8194689 A JP 8194689A JP 8194689 A JP8194689 A JP 8194689A JP H02260223 A JPH02260223 A JP H02260223A
- Authority
- JP
- Japan
- Prior art keywords
- recording medium
- carbon black
- magnetic recording
- back coat
- deposited
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000005291 magnetic effect Effects 0.000 title claims description 29
- 239000006229 carbon black Substances 0.000 claims abstract description 22
- 239000011230 binding agent Substances 0.000 claims abstract description 11
- 229920001577 copolymer Polymers 0.000 claims abstract description 10
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 claims abstract description 9
- 239000000696 magnetic material Substances 0.000 claims abstract description 8
- 239000002245 particle Substances 0.000 claims description 6
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 claims description 2
- 239000000178 monomer Substances 0.000 claims description 2
- 239000006185 dispersion Substances 0.000 abstract description 10
- 239000000843 powder Substances 0.000 abstract description 6
- 230000005294 ferromagnetic effect Effects 0.000 abstract description 3
- 239000011247 coating layer Substances 0.000 abstract 3
- 239000003973 paint Substances 0.000 description 18
- 235000019241 carbon black Nutrition 0.000 description 17
- 239000010408 film Substances 0.000 description 12
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 9
- 239000000203 mixture Substances 0.000 description 8
- 239000000758 substrate Substances 0.000 description 8
- 239000011248 coating agent Substances 0.000 description 7
- 238000000576 coating method Methods 0.000 description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 5
- 229920002635 polyurethane Polymers 0.000 description 5
- 239000004576 sand Substances 0.000 description 5
- 229920000728 polyester Polymers 0.000 description 4
- 239000004814 polyurethane Substances 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- 229910000859 α-Fe Inorganic materials 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- 239000002270 dispersing agent Substances 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 230000003746 surface roughness Effects 0.000 description 3
- 239000010409 thin film Substances 0.000 description 3
- 229920002554 vinyl polymer Polymers 0.000 description 3
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Natural products CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 2
- 241000872198 Serjania polyphylla Species 0.000 description 2
- 235000021355 Stearic acid Nutrition 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 235000014113 dietary fatty acids Nutrition 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229930195729 fatty acid Natural products 0.000 description 2
- 239000000194 fatty acid Substances 0.000 description 2
- 238000004898 kneading Methods 0.000 description 2
- 239000000314 lubricant Substances 0.000 description 2
- 239000006247 magnetic powder Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 2
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000008117 stearic acid Substances 0.000 description 2
- JSZOAYXJRCEYSX-UHFFFAOYSA-N 1-nitropropane Chemical compound CCC[N+]([O-])=O JSZOAYXJRCEYSX-UHFFFAOYSA-N 0.000 description 1
- QQZOPKMRPOGIEB-UHFFFAOYSA-N 2-Oxohexane Chemical compound CCCCC(C)=O QQZOPKMRPOGIEB-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 241000557626 Corvus corax Species 0.000 description 1
- NTIZESTWPVYFNL-UHFFFAOYSA-N Methyl isobutyl ketone Chemical compound CC(C)CC(C)=O NTIZESTWPVYFNL-UHFFFAOYSA-N 0.000 description 1
- UIHCLUNTQKBZGK-UHFFFAOYSA-N Methyl isobutyl ketone Natural products CCC(C)C(C)=O UIHCLUNTQKBZGK-UHFFFAOYSA-N 0.000 description 1
- 239000000020 Nitrocellulose Substances 0.000 description 1
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 1
- 241000282320 Panthera leo Species 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000000498 ball milling Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 150000004665 fatty acids Chemical class 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 229920001220 nitrocellulos Polymers 0.000 description 1
- AJCDFVKYMIUXCR-UHFFFAOYSA-N oxobarium;oxo(oxoferriooxy)iron Chemical compound [Ba]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O AJCDFVKYMIUXCR-UHFFFAOYSA-N 0.000 description 1
- -1 polyethylene terephthalate Polymers 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 229920001228 polyisocyanate Polymers 0.000 description 1
- 239000005056 polyisocyanate Substances 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 229920005749 polyurethane resin Polymers 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 239000008096 xylene Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】
［発明の目的］
（産業上の利用分野）
本発明は磁性粉末が良好に分散され、かつ優れ耐久性を
有する磁気記録媒体に関する。Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a magnetic recording medium in which magnetic powder is well dispersed and has excellent durability.
（従来の技術）
周知のように、磁気記録媒体はオーディオ、ビデオ、コ
ンピュータ、磁気ディスクなど広範に使用されており、
また記録する情報量も年々増加の一途をたどっている。(Prior Art) As is well known, magnetic recording media are widely used in audio, video, computers, magnetic disks, etc.
Furthermore, the amount of information recorded is increasing year by year.
そのため、磁気記録媒体に対しては記Ｂ密度の向上が益
々要求されている。Therefore, magnetic recording media are increasingly required to improve the recording B density.
この要求に対して、磁性粉末の粒径を小さくしたり、バ
リウムフェライトなどの超微粒六万品粉末を利用するこ
とが試みられている。In response to this demand, attempts have been made to reduce the particle size of the magnetic powder or to use ultrafine powder such as barium ferrite.
こうした動向に伴い、上記高密度記録用媒体に用いるベ
ースフィルムに対する要求も厳しくなってきており、特
にバックコート層については、摩擦係数１表面抵抗の低
減、耐久性の向上および機械的強度の確保など様々な要
求を満たすために、種々のカーボンブラックを混合、分
散することが必要とされている。Along with these trends, the requirements for the base film used in the above-mentioned high-density recording media are also becoming stricter.In particular, for the back coat layer, there are demands such as reducing the coefficient of friction 1 surface resistance, improving durability, and ensuring mechanical strength. In order to meet various requirements, it is necessary to mix and disperse various carbon blacks.
しかしながら、カーボンブラックをバックコート層を成
すたとえばポリウレタン樹脂に分散させることは容易で
はなく、サンドミルなどの単一工程では不可能であり、
予備分散としてボールミルやロール練りなど高粘度で高
いシェアをかけないと分散が進まず、分散が不十分の場
合には、ろ過工程でフィルターのめづまりの原因になる
。また、単一工程で分散させるために必要以上に分散剤
を加えると、形成した塗膜（バックコート）の機械的強
度が劣るため、剥離や粉落ちなどの原因になる。However, it is not easy to disperse carbon black into the polyurethane resin that forms the back coat layer, and it is not possible in a single process such as a sand mill.
Dispersion will not proceed unless a high viscosity and high shear is applied during preliminary dispersion, such as by ball milling or roll kneading, and if the dispersion is insufficient, it may cause clogging of the filter during the filtration process. Furthermore, if more dispersant is added than necessary for dispersion in a single step, the mechanical strength of the formed coating film (back coat) will be poor, resulting in peeling and powder falling.
上記カーボンブラックの分散の困難さは特に比表面積が
大きくなるほど顕著であり、しがち比表面積の大きなカ
ーボンブラックは今後益々要求されるバックコート表面
の導電性向上に極めて重要な役割を果たすものと言える
。The difficulty in dispersing the carbon black mentioned above is particularly noticeable as the specific surface area increases, and it can be said that carbon black with a large specific surface area will play an extremely important role in improving the conductivity of the back coat surface, which will be increasingly required in the future. .
（発明が解決しようとする課題）
上記のように、従来バックコート形成に用いられている
樹脂、たとえばポリウレタン、ポリエステル、塩ビ酢ビ
共重合体などに対しては、カーボンなどを分散させるこ
とが極めて困難であり、ロール練りなどの予備分散や種
々の分散剤を併用することによって分散を行っている。(Problems to be Solved by the Invention) As mentioned above, it is extremely difficult to disperse carbon, etc. into resins conventionally used for forming back coats, such as polyurethane, polyester, and vinyl chloride/vinyl acetate copolymers. This is difficult, and dispersion is carried out by preliminary dispersion such as roll kneading or by the combined use of various dispersants.
しかし分散剤などを多量に使用すると形成した塗膜の機
械的強度が弱まり、粉落ちの原因となり耐久性も劣化す
る問題が生じている。しかしながら、一方では分散工程
の簡略化や塗膜の機械的強度を確保しなければならない
という課題があった。However, when a large amount of dispersant is used, the mechanical strength of the formed coating film is weakened, causing powder to fall off, and durability is also deteriorated. However, on the other hand, there were problems in that the dispersion process had to be simplified and the mechanical strength of the coating film had to be ensured.
本発明は、係る従来技術の課題を解決すべくなされたも
ので、上記問題の解決されたバックコート層を有する磁
気記録媒体を提供することを目的とする。The present invention was made to solve the problems of the prior art, and an object of the present invention is to provide a magnetic recording medium having a back coat layer in which the above problems are solved.
［発明の構成］
（課題を解決するための手段）
本発明によれば、磁気記録媒体の構成において、非磁性
基体上に強磁性粉末をバインダとともに被着形成して成
る磁性体と、前記磁性体を被着形成した非磁性基体の裏
面に被着形成したアミノ基付加型塩化ビニル系共重合体
とカーボンブラックを主成分とするバックコート層とを
有することを特徴としている。[Structure of the Invention] (Means for Solving the Problems) According to the present invention, in the structure of a magnetic recording medium, a magnetic body formed by depositing ferromagnetic powder together with a binder on a non-magnetic substrate; It is characterized by having a back coat layer mainly composed of an amino group-added vinyl chloride copolymer and carbon black, which is deposited on the back side of the nonmagnetic substrate on which the body is deposited.
本発明に係る磁気記録媒体の磁性体形成に使用する強磁
性粉末としては、たとえばＣｒＯ２，７Ｐｅ２０３ 、
Ｃｏ変性７ Ｆ（！２０３ 、および一般式： Ｍａ
Ｏｎ （Ｐｅ Ｍｂ ） ２０３（式中、ＨａはＢａ
ＸＳｒ、Ｃａ、 Ｐｂのいずれか１種の元素を表し、Ｍ
ｂはＣｏ１Ｚｎ、 Ｔｉｓ旧、Ｍｎ５ｌｎｓ ＣｕＳＧ
ｅ。Examples of the ferromagnetic powder used to form the magnetic material of the magnetic recording medium according to the present invention include CrO2,7Pe203,
Co-modified 7F (!203, and general formula: Ma
On (Pe Mb ) 203 (wherein, Ha is Ba
Represents any one element of XSr, Ca, Pb, M
b is Co1Zn, Tis old, Mn5lns CuSG
e.
Ｓｎ、Ｎｂ５Ｓｒ、Ｚｒの群から選ばれる少なくとも１
種、の元素を表し、−は０〜ｌ、ｎは５．４〜９．０の
数を表す）で示される置換型六方晶フェライトが用いら
れる。これらのうちＢａフェライトなどに代表される置
換型六方晶フェライトは、高記録密度の媒体を与えるの
で特に好ましい。At least one selected from the group of Sn, Nb5Sr, and Zr
A substituted hexagonal ferrite is used, which is represented by a number of 0 to 1, and n is a number of 5.4 to 9.0. Among these, substituted hexagonal ferrites such as Ba ferrite are particularly preferred since they provide a medium with high recording density.
また、本発明に係る磁気記録媒体の非磁性基体としては
、ポリエチレンテレフタレート薄膜やポリエステル薄膜
など、従来の非磁性基体と同質の基体を用いることがで
きる。Further, as the nonmagnetic substrate of the magnetic recording medium according to the present invention, a substrate having the same quality as a conventional nonmagnetic substrate, such as a polyethylene terephthalate thin film or a polyester thin film, can be used.
この非磁性基体を介して磁性体層の裏面にバックコート
層を形成するにあたって用いるカーボンブラックは平均
粒径が１５μ霜から３５０μｍ程度のものが好ましく、
特に粒径が小さく、比表面積が大きいカーボンブラック
を用いた場合にその効果が顕著である。この種のカーボ
ンブラックとしてはたとえば、アシュラドケミカル社の
ＬＪｎｌｔｅｄ ＸＣ−３０１７、ＵｎｉＬｅｄ ８０
０４ 、三菱化成社製の善（３００，３１５０，３２５
０、ライオンアクゾ社製のケッチエンブラックＥＣ，キ
ャボット社製のＶＵＬＣＵＮ ＳＣ、コロンビアンカー
ボン日本社製（７）ＲＡＶＥＮ ３２００、Ｃ０ＮＤｕ
ＣＴＥＸ９７５およびＣ０ＮＤＵＣＴＥＸ ＳＣ（いず
れも商品名）などを挙げることができる。その他のカー
ボンブラックとしては、デグサ社製のＰｒ１ｎＬｅｘ
ＶおよびＰｒ１ｎｔｅｘ１４０、三菱化成社製の４５（
Ｂ） 、コロンビアンカーボン日本社製（７）ＲＡＶＥ
Ｎ２０００ 、ＲＡＶＥＮＭＴ−Ｐ 、キャボット社製
のＲＥＧＡＬ３３０Ｒ、、ＳｔｅｒｌｌｎｇＰＴおよび
５ｔｃｒｌ ＩｎｇＭＴｓ旭カーボン社製の旭ｌｌ５−
５００ （いずれも商品名）なども例示され、またこれ
らのカーボンブラックはｐ！１３以下のものが好ましい
。The carbon black used to form the back coat layer on the back surface of the magnetic layer via this non-magnetic substrate preferably has an average particle size of about 15 μm to 350 μm.
This effect is particularly noticeable when carbon black with a small particle size and a large specific surface area is used. Examples of this type of carbon black include LJnlted XC-3017 and UniLed 80 from Ashrad Chemical Company.
04, Zen (300, 3150, 325 manufactured by Mitsubishi Chemical Corporation)
0, Ketchen Black EC manufactured by Lion Akzo, VULCUN SC manufactured by Cabot, Columbian Carbon manufactured by Nihon Sha (7) RAVEN 3200, C0NDu
Examples include CTEX975 and CONDUCTEX SC (both are trade names). Other carbon blacks include Pr1nLex manufactured by Degussa
V and Pr1ntex140, 45 manufactured by Mitsubishi Chemical Corporation (
B), Columbian Carbon made by Nihon Sha (7) RAVE
N2000, RAVENMT-P, REGAL330R made by Cabot, SterllngPT and 5tcrl IngMTs Asahill5- made by Asahi Carbon Co., Ltd.
500 (both are trade names) are also exemplified, and these carbon blacks are p! It is preferably 13 or less.
しかして、これらのカーボンブラックはバインダおよび
溶剤と混合して塗料化し、非磁性基体の所定面に塗布、
乾燥して所要のバックコート塗膜を形成するが、この場
合バインダのカーボンブラックに対する比率は、カーボ
ンブラックの総量を１（１０Ｍ回部としたとき、１５〜
７０重量部程度回部ることが好ましい。つまり１５重量
部未満では塗膜の機械的強度が低下して粉落ち、剥離の
原因となるとともに面粗度も悪くなる傾向があるため好
ましくない。また、７０重量部を越えると塗膜の表面電
気抵抗が高くなるとともに赤外線遮光率が低下する傾向
があるため好ましくない。しかして、バックコート形成
に用いるバインダとしてのアミノ基付加型塩化ビニル系
共重合体は、この共重合体を構成するモノマ成分の少な
−くともｌＯｗｅｔ％が酢酸ビニルであることが好まし
い。However, these carbon blacks are mixed with a binder and a solvent to form a paint, and then applied to a predetermined surface of a non-magnetic substrate.
It dries to form the required back coat film. In this case, the ratio of binder to carbon black is 15 to 15 when the total amount of carbon black is 1 (10M parts).
It is preferable to use about 70 parts by weight. In other words, if it is less than 15 parts by weight, the mechanical strength of the coating film decreases, causing flaking and peeling, and the surface roughness tends to deteriorate, which is not preferable. Moreover, if it exceeds 70 parts by weight, the surface electrical resistance of the coating film tends to increase and the infrared ray shielding rate tends to decrease, which is not preferable. Therefore, in the amino group-added vinyl chloride copolymer used as a binder for forming the back coat, it is preferable that at least 10% of the monomer components constituting the copolymer be vinyl acetate.
さらにバックコート形成用の塗料調製に用いる溶剤とし
ては、トルエン、キシレン、シクロヘキサノン、メチル
ブチルケトン、メチルイソブチルケトン、ニトロプロパ
ン、テトラヒドロフラン、イソプロピルアルコールなど
、前述のバインダを溶解するものが用いられる。Further, as the solvent used for preparing the paint for forming the back coat, those which dissolve the above-mentioned binder are used, such as toluene, xylene, cyclohexanone, methyl butyl ketone, methyl isobutyl ketone, nitropropane, tetrahydrofuran, and isopropyl alcohol.
なお、バックコート塗膜の成分には、必要に応じて脂肪
酸あるいは脂肪酸アルキルエステル系、シリコーン系お
よびフッ素化系炭化水素系潤滑剤、またはこれらの混合
物あるいは化合物などの潤滑剤を加えることができる。In addition, a lubricant such as a fatty acid or fatty acid alkyl ester type, a silicone type, a fluorinated hydrocarbon type lubricant, or a mixture or compound thereof can be added to the components of the back coat film, if necessary.
本発明に係る磁気記録媒体のバックコート層を形成する
にあたっては、まず、上記諸成分を混合し、ボールミル
、サンドミル、ペイントシェーカー等によって混合分散
して塗料化する。次に、得られた塗料に必要に応じてポ
リイソシアネート系硬化剤を加え、たとえばリバースロ
ールコータ、グラビアコータなどにより非磁性基体上に
０．３〜１．５μｍの厚みで塗布し、乾燥処理を施した
後、４０〜６０℃のオーブン中にてｌ〜４日間キュアを
してバックコート層とする。なお、このバックコート層
の表面性は、最大面粗さ（Ｒｓａｘ）が０．３μｍ以下
、１０点平均粗さ（Ｒｚ）が０．２５μｍ以下であるこ
とが望ましい。つまり、これ以上に面積度が良いと摩擦
係数が増大し、特に高温高湿下ではりつきなどの現象が
生じ易い。また、Ｉ？ｓａｘが０．３μｍを超えた場合
、バックコート層の凹凸が磁性層に転写してドロップア
ウトの原因となるため、特に高密度記録が要求されると
きのバックコート層としては好ましくない。In forming the back coat layer of the magnetic recording medium according to the present invention, first, the above-mentioned components are mixed and mixed and dispersed using a ball mill, sand mill, paint shaker, etc. to form a paint. Next, a polyisocyanate-based curing agent is added to the obtained paint as necessary, and it is coated on a non-magnetic substrate to a thickness of 0.3 to 1.5 μm using, for example, a reverse roll coater or a gravure coater, and then dried. After application, it is cured in an oven at 40 to 60°C for 1 to 4 days to form a back coat layer. As for the surface properties of this back coat layer, it is desirable that the maximum surface roughness (Rsax) is 0.3 μm or less and the 10-point average roughness (Rz) is 0.25 μm or less. In other words, if the surface area is higher than this, the coefficient of friction increases, and phenomena such as sticking are likely to occur, especially under high temperature and high humidity conditions. Also, I? If sax exceeds 0.3 μm, the unevenness of the back coat layer will be transferred to the magnetic layer and cause dropouts, so it is not preferred as a back coat layer especially when high-density recording is required.
（作用）
本発明の磁気記録媒体はバックコート層において、アミ
ノ基付加型の塩化ビニル共重合体を使用したことにより
、カーボンブラックの分散が極めて良好であり、かつ、
被着形成した塗膜は強度に優れているため、表面性、走
行性、耐久性に優れ、またその塗膜のスティフネスが十
分であり、ヘッドタッチの良好な磁気記録媒体として機
能する。(Function) The magnetic recording medium of the present invention uses an amino group-added vinyl chloride copolymer in the back coat layer, so that carbon black is extremely well dispersed, and
The coated film has excellent strength, has excellent surface properties, runnability, and durability, and has sufficient stiffness, so that it functions as a magnetic recording medium with good head touch.
（実施例） 以下、本発明の実施例について説明する。(Example) Examples of the present invention will be described below.
実施例Ｉ
Ａ）磁性層の作製
Ｃｏ−Ｔｌ置換型Ｂａフェライト １００重量部ポ
リウレタン ５ 〃ニトロセルロー
ス ５ 〃ステアリン酸
２ ／／アルミナ ３
〃メチルエチルケトン／トルエン／
シクロヘキサノンの混合物 ２３０〃上紀組成分を
混合した後、サンドグラインダによりさらに２時間分散
して塗料化した。次いで、得られた塗料１００重量部に
対してコロネートしく商品名、日本ポリウレタン社製）
を０．４重量部添加した後、リバースロールコータによ
りポリエステル薄膜上に膜厚３μｍとなるように塗布し
、４０℃で２日間キュアして磁性体を作製した。Example I A) Preparation of magnetic layer Co-Tl substituted Ba ferrite 100 parts by weight Polyurethane 5 Nitrocellulose 5 Stearic acid
2 // Alumina 3
〃Mixture of methyl ethyl ketone/toluene/cyclohexanone 230〃After mixing the upper period components, the mixture was further dispersed for 2 hours using a sand grinder to form a paint. Then, to 100 parts by weight of the obtained paint, add Coronate (trade name, manufactured by Nippon Polyurethane Co., Ltd.)
After adding 0.4 parts by weight, the mixture was coated onto a polyester thin film using a reverse roll coater to a thickness of 3 μm, and cured at 40° C. for 2 days to produce a magnetic material.
Ｂ）バックコート層の作製
カーボンブラック １００重量部（平均粒
径５０μ■、比表面積８００■／ｇ）バインダー
（アミノ基付加型塩酢ビレジン）１００〃ステアリン酸
ｌ 〃トルエン／
シクロヘキサノンの混合物 ８００〃上記組成分を
混合した後、サンドグラインダにより分散して塗料化し
た。B) Preparation of back coat layer Carbon black 100 parts by weight (average particle size 50μ■, specific surface area 800■/g) Binder (amino group-added salt acetic acid vinyl resin) 100 Stearic acid 1 Toluene/cyclohexanone mixture 800 Above After the components were mixed, they were dispersed using a sand grinder to form a paint.
実施例２
実施例１において、カーボンブラックの平均粒径を１７
μ厘とした以外は実施例１の場合と同様にして塗料化し
、バックコート用塗料を調製した。Example 2 In Example 1, the average particle size of carbon black was changed to 17
A paint for back coat was prepared in the same manner as in Example 1 except that the thickness was changed to μm.
実施例３
実施例１において、カーボンブラックの比表面積を１０
００ｒｄＩ／ｇとした以外は実施例１の場合と同様にし
て塗料化し、バックコート用塗料を調製した。Example 3 In Example 1, the specific surface area of carbon black was 10
A paint for back coat was prepared in the same manner as in Example 1 except that the amount of 0rdI/g was changed to 0rdI/g.
比較例１
実施例１におけるバインダーをポリエステルとした以外
は実施例１の場合と同様にして塗料化し、バックコート
用塗料を調製した。Comparative Example 1 A back coat paint was prepared in the same manner as in Example 1 except that polyester was used as the binder.
比較例２
実施例１におけるバインダーをポリウレタンと塩酢ビレ
ジンの混合物とした以外は実施例１の場合と同様にして
塗料化し、バックコート用塗料を調製した。Comparative Example 2 A back coat paint was prepared in the same manner as in Example 1 except that the binder in Example 1 was a mixture of polyurethane and salt-acetate vinyl resin.
比較例３
実施例３のバインダーをポリウレタンと塩酢ビレジンの
混合物とした以外は実施例３と同様にして塗料化し、バ
ックコート用塗料を調製した。Comparative Example 3 A back coat paint was prepared in the same manner as in Example 3 except that the binder in Example 3 was a mixture of polyurethane and salt-acetate vinyl resin.
比較例４
比較例３において組成分を混合後、ボールミルを２４ｈ
かげた後、サンドグラインダによりさらに分散して塗料
化し、バックコート用塗料を調製した。Comparative Example 4 After mixing the components in Comparative Example 3, the ball mill was heated for 24 hours.
After shading, the mixture was further dispersed using a sand grinder to form a paint, thereby preparing a back coat paint.
上記調製したバックコート用塗料７例を０本ろ器（株）
社製＋１７−０４を用いてろ過特性を調べた（４０Ｊ２
以上通るものを分散良好品とみなす）。0 bottles of the 7 examples of back coat paints prepared above were purchased from Roki Co., Ltd.
The filtration characteristics were investigated using +17-04 manufactured by Co., Ltd. (40J2
Items that pass above are considered to have good dispersion).
さらに、上記で得た塗料１００重量部に対してコロネー
トＬを１．５重量部添加した後、グラビアコータにより
Ａ）で前記実施例の場合と同様にして形成した磁性体の
裏側に膜厚０．３〜１．５μｌの範囲で塗布し、４０℃
で２日間キュアし、ｌ／２インチに裁断してバックコー
ト層を作製した。Furthermore, after adding 1.5 parts by weight of Coronate L to 100 parts by weight of the paint obtained above, a film with a thickness of 0 Apply in the range of .3 to 1.5 μl and incubate at 40°C.
It was cured for 2 days and cut into 1/2 inch pieces to prepare a back coat layer.
以上の実施例および比較例で得た磁気記録媒体について
の特性評価の結果を前記ろ過特性とともに第１表に示す
。 （以下余白）表１
とができ、コストの低下につなげることもできる。The results of characteristic evaluation of the magnetic recording media obtained in the above Examples and Comparative Examples are shown in Table 1 together with the above-mentioned filtration characteristics. (Left below) Table 1 This can also lead to lower costs.
そのうえ、本発明によれば、バックコート層の表面粗度
を制御した場合、バックコート層の凹凸が磁性体に転写
されるために生じるドロップアウトが抑止されるので、
記録再生時のＳ／Ｎ特性を向上させることができる。Furthermore, according to the present invention, when the surface roughness of the back coat layer is controlled, dropouts that occur due to the unevenness of the back coat layer being transferred to the magnetic material are suppressed.
S/N characteristics during recording and reproduction can be improved.
［発明の効果］
以上説明したように、本発明の磁気記録媒体はバックコ
ート塗膜の強度が優れているため耐久性も良好でまたバ
ックコート、塗膜のスティフネスが十分なためへラドタ
ッチも極めて良好となる。[Effects of the Invention] As explained above, the magnetic recording medium of the present invention has excellent durability due to the excellent strength of the back coat coating film, and also has excellent hardness due to the sufficient stiffness of the back coat and coating film. Becomes good.
したがって、本発明によれば記録密度がさらに向上され
た磁気記録媒体を得ることができる。Therefore, according to the present invention, a magnetic recording medium with further improved recording density can be obtained.
しかも、本発明においてバックコート形成に使用される
カーボン塗料は極めて分散性に優れていて、分散のため
に費やされる工程を簡略化するこ出願人 株式
会社 東芝Moreover, the carbon paint used to form the back coat in the present invention has extremely excellent dispersibility, which simplifies the process required for dispersion.Applicant: Toshiba Corporation
Claims (3)
形成して成る磁気記録媒体において、前記磁性体を被着
形成した非磁性支持体の裏面にアミノ基付加型塩化ビニ
ル系共重合体とカーボンブラックを主成分とするバック
コート層を施したことを特徴とする磁気記録媒体。(1) In a magnetic recording medium in which a magnetic material is deposited together with a binder on a non-magnetic support, an amino group-added vinyl chloride copolymer is attached to the back surface of the non-magnetic support on which the magnetic material is deposited. A magnetic recording medium characterized by having a back coat layer containing carbon black as a main component.
て、かつ平均粒径が１５〜５０μｍであることを特徴と
する磁気記録媒体。(2) A magnetic recording medium, wherein the carbon black according to claim 1 has a pH of 3 or less and an average particle size of 15 to 50 μm.
を構成するモノマ成分の少くとも１０ｗｔ％が酢酸ビニ
ルであることを特徴とする磁気記録媒体。(3) A magnetic recording medium characterized in that at least 10 wt % of the monomer components constituting the amino group-added vinyl chloride copolymer according to claim 1 is vinyl acetate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8194689A JPH02260223A (en) | 1989-03-31 | 1989-03-31 | Magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8194689A JPH02260223A (en) | 1989-03-31 | 1989-03-31 | Magnetic recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02260223A true JPH02260223A (en) | 1990-10-23 |
Family
ID=13760669
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8194689A Pending JPH02260223A (en) | 1989-03-31 | 1989-03-31 | Magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02260223A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0651379A1 (en) * | 1993-05-14 | 1995-05-03 | TDK Corporation | Magnetic recording medium |
| US5851650A (en) * | 1996-02-15 | 1998-12-22 | Tdk Corporation | Magnetic recording medium including a backcoat layer containing a specified vinyl chloride copolymer |
-
1989
- 1989-03-31 JP JP8194689A patent/JPH02260223A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0651379A1 (en) * | 1993-05-14 | 1995-05-03 | TDK Corporation | Magnetic recording medium |
| EP0651379A4 (en) * | 1993-05-14 | 1995-11-22 | Tdk Corp | Magnetic recording medium. |
| US5851650A (en) * | 1996-02-15 | 1998-12-22 | Tdk Corporation | Magnetic recording medium including a backcoat layer containing a specified vinyl chloride copolymer |
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