JPH0479057B2 - - Google Patents
Info
- Publication number
- JPH0479057B2 JPH0479057B2 JP57129778A JP12977882A JPH0479057B2 JP H0479057 B2 JPH0479057 B2 JP H0479057B2 JP 57129778 A JP57129778 A JP 57129778A JP 12977882 A JP12977882 A JP 12977882A JP H0479057 B2 JPH0479057 B2 JP H0479057B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- carbon black
- sample
- magnetic layer
- parts
- 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.)
- Expired - Lifetime
Links
- 230000005291 magnetic effect Effects 0.000 claims description 33
- 239000006229 carbon black Substances 0.000 claims description 19
- 239000011164 primary particle Substances 0.000 claims description 5
- 241000872198 Serjania polyphylla Species 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 3
- 235000019241 carbon black Nutrition 0.000 description 18
- 239000000696 magnetic material Substances 0.000 description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 7
- -1 etc. Substances 0.000 description 7
- 238000000034 method Methods 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- 229910001566 austenite Inorganic materials 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 235000014113 dietary fatty acids Nutrition 0.000 description 3
- 239000000194 fatty acid Substances 0.000 description 3
- 229930195729 fatty acid Natural products 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 229910015189 FeOx Inorganic materials 0.000 description 2
- 239000000020 Nitrocellulose Substances 0.000 description 2
- 239000004952 Polyamide Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 description 2
- DOIRQSBPFJWKBE-UHFFFAOYSA-N dibutyl phthalate Chemical compound CCCCOC(=O)C1=CC=CC=C1C(=O)OCCCC DOIRQSBPFJWKBE-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000000314 lubricant Substances 0.000 description 2
- 229920001220 nitrocellulos Polymers 0.000 description 2
- 229920002647 polyamide Polymers 0.000 description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 description 2
- 239000005020 polyethylene terephthalate Substances 0.000 description 2
- 229920001228 polyisocyanate Polymers 0.000 description 2
- 239000005056 polyisocyanate Substances 0.000 description 2
- 229920002635 polyurethane Polymers 0.000 description 2
- 239000004814 polyurethane Substances 0.000 description 2
- WRIDQFICGBMAFQ-UHFFFAOYSA-N (E)-8-Octadecenoic acid Natural products CCCCCCCCCC=CCCCCCCC(O)=O WRIDQFICGBMAFQ-UHFFFAOYSA-N 0.000 description 1
- IIZPXYDJLKNOIY-JXPKJXOSSA-N 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine Chemical compound CCCCCCCCCCCCCCCC(=O)OC[C@H](COP([O-])(=O)OCC[N+](C)(C)C)OC(=O)CCC\C=C/C\C=C/C\C=C/C\C=C/CCCCC IIZPXYDJLKNOIY-JXPKJXOSSA-N 0.000 description 1
- LQJBNNIYVWPHFW-UHFFFAOYSA-N 20:1omega9c fatty acid Natural products CCCCCCCCCCC=CCCCCCCCC(O)=O LQJBNNIYVWPHFW-UHFFFAOYSA-N 0.000 description 1
- QSBYPNXLFMSGKH-UHFFFAOYSA-N 9-Heptadecensaeure Natural products CCCCCCCC=CCCCCCCCC(O)=O QSBYPNXLFMSGKH-UHFFFAOYSA-N 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910020630 Co Ni Inorganic materials 0.000 description 1
- 229910002440 Co–Ni Inorganic materials 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- 229920000459 Nitrile rubber Polymers 0.000 description 1
- 239000005642 Oleic acid Substances 0.000 description 1
- ZQPPMHVWECSIRJ-UHFFFAOYSA-N Oleic acid Natural products CCCCCCCCC=CCCCCCCCC(O)=O ZQPPMHVWECSIRJ-UHFFFAOYSA-N 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- BCKXLBQYZLBQEK-KVVVOXFISA-M Sodium oleate Chemical compound [Na+].CCCCCCCC\C=C/CCCCCCCC([O-])=O BCKXLBQYZLBQEK-KVVVOXFISA-M 0.000 description 1
- YSMRWXYRXBRSND-UHFFFAOYSA-N TOTP Chemical compound CC1=CC=CC=C1OP(=O)(OC=1C(=CC=CC=1)C)OC1=CC=CC=C1C YSMRWXYRXBRSND-UHFFFAOYSA-N 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- 229920002433 Vinyl chloride-vinyl acetate copolymer Polymers 0.000 description 1
- 229910001297 Zn alloy Inorganic materials 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 239000003082 abrasive agent Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 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
- 238000004458 analytical method Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- AYOHIQLKSOJJQH-UHFFFAOYSA-N dibutyltin Chemical compound CCCC[Sn]CCCC AYOHIQLKSOJJQH-UHFFFAOYSA-N 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000000635 electron micrograph Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 150000004665 fatty acids Chemical class 0.000 description 1
- 150000002193 fatty amides Chemical class 0.000 description 1
- 230000005294 ferromagnetic effect Effects 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000002223 garnet Substances 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- QXJSBBXBKPUZAA-UHFFFAOYSA-N isooleic acid Natural products CCCCCCCC=CCCCCCCCCC(O)=O QXJSBBXBKPUZAA-UHFFFAOYSA-N 0.000 description 1
- 239000000787 lecithin Substances 0.000 description 1
- 229940067606 lecithin Drugs 0.000 description 1
- 235000010445 lecithin Nutrition 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229940057995 liquid paraffin Drugs 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- ZQPPMHVWECSIRJ-KTKRTIGZSA-N oleic acid Chemical compound CCCCCCCC\C=C/CCCCCCCC(O)=O ZQPPMHVWECSIRJ-KTKRTIGZSA-N 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
- 239000003973 paint Substances 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920003207 poly(ethylene-2,6-naphthalate) Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 239000011112 polyethylene naphthalate Substances 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 230000003449 preventive effect Effects 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 239000000344 soap Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 238000010561 standard procedure Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
- G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
- G11B5/708—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by addition of non-magnetic particles to the layer
Description
本発明は磁気記録体に関し、特に改良された磁
性体配向性と耐久性を持つた磁気記録体に関す
る。
従来より帯電防止のために磁性層中にカーボン
ブラツクが添加されている。しかし、まだ充分な
カーボンブラツクμmは見出されていない。
磁気記録体は電磁変換特性の点から磁性体の配
向性を向上させる様に設計されなければならな
い。同時に、磁性層の耐久性が大きいことも要求
される。これらはオーデオテープよりもビデオテ
ープ、メモリーテープの如き精密系テープにおい
て強く要求される。
それ故に、本発明の目的は優れた磁性体配向性
と耐久性を有する磁気記録体を提供するにある。
上記の特性を満足させるためには、磁性層へ添
加する研磨剤、バインダー組成、磁性体等、或い
は分散技術、磁性層の表面成形条件を検討する方
法があるが、本発明者達は従来帯電防止用として
使用されているカーボンブラツクを選択すること
により上記の目的が達成されることを見出した。
即ち、本発明は非磁性支持体とその上に設けられ
た磁性層からなり、該磁性層は30mμより大きい
平均一次粒子サイズと、６未満のPHとを有するカ
ーボンブラツクを含有する磁気記録体に関する。
本発明において重要な点はカーボンブラツクの
平均一次粒子サイズが30mμより大きいことであ
り、特に好ましくは50mμ以上、より好ましくは
50mμ〜150mμである。粒子サイズが小さいと、
磁性層の耐久性が不充分となり、また大きいもの
は市販品が入手しにくい。本発明のもう一つの重
要な点はカーボンブラツクのPHが６未満であり、
特に好ましくは４未満である。PHがこれより大き
いと、配向性が劣り本発明の効果が得られない。
本発明に使用できるカーボンブラツクとして
は、たとえば、コロンビアンカーボン製
「Raven14」、「Raven16」、デグサ（Degussa）製
「SPecial Black10」、「SPecial Black25（２／
０）」等がある。これらのカーボンブラツクは２
種以上混合して使用することができる。カーボン
ブラツクの添加量は磁性体100重量部に対して１
〜20重量部、特に３〜15重量部である。添加量が
余りに少ないと帯電防止効果が減少し、余り多い
と磁性体の充填度が低下し、電磁変換特性が劣化
する。
磁性体としては、γ−Fe2O3、FeOx（1.33＜ｘ
＜1.5）、CrO2、Co添加γ−Fe2O3、Co添加FeOx
（1.33＜ｘ＜1.5）、平板状バリウムフエライト、
Fe−Co−Ni合金粉末、Fe−Zn合金粉末など通常
の強磁性粉末が使用できる。これらの磁性体は単
独又は混合して使用できる。磁性体の形状は特に
制限されず、粒状、針状、紡錘状などがある。
バインダーとしては、塩化ビニル−酢酸ビニル
共重合体、セルロース誘導体（たとえば、ニトロ
セルロース）、ポリウレタン、ニトリル−ブタジ
エンゴム、スチレン−ブタジエンゴム、ポリエス
テル、ポリアミド、ポリイソシアネート等が使用
できる。
本発明の磁性層には、脂肪酸、脂肪酸エステ
ル、脂肪族アミド、ソルビタン脂肪酸エステル、
流動パラフイン、シリコンオイル、フツ素系オイ
ルの如き液状潤滑剤；Cr2O3、アルミナ、ガーネ
ツト、α−Fe2O3の如き研磨剤；レシチン、オレ
イン酸ナトリウムの如き分散剤；金属石けん、ジ
ブチルスズジカルボキシレートの如き安定剤；ジ
ブチルフタレート、トリクレジルホスフエートの
如き可塑剤；グラフアイト、MoS2の如き固体潤
滑剤などを含有させることができる。
磁性層が塗布される支持体としては、ポリエチ
レンテレフタレート、ポリエチレンナフタレー
ト、ポリアミド、ポリイミド、塩化ビニル系フイ
ルム等がある。支持体には必要によりバツク層が
塗布されてもよい。支持体の両面の平滑性は互に
変えることもできる。更に、支持体の片面（磁性
層と反対側の表面）に、磁性層塗布前又は後に、
潤滑剤又は界面活性剤を塗布することができる。
本発明の磁気記録体を製造するための組成、方
法等については特公昭56−26980号に記載されて
いる。
以下に本発明を実施例に従つて具体的に説明す
る。実施例中「部」は「重量部」を示す。
実施例 １
次の組成をボールミルで分散して磁性塗液を調
製し、15μ厚のポリエチレンテレフタレートフイ
ルムに乾燥厚で5μとなる様に塗布した。磁場配
向処理は磁性層が未乾のときにソレノイドを用い
て塗布長さ方向に行なつた。磁性層の表面成形処
理後、1/2吋巾に裁断しVHS用ビデオテープ（サ
ンプルNo.１）を得た。
Co添加γ−Fe2O3 100部
カーボンブラツク ５部
コロンビアンカーボン製「Raven14」
平均一次粒子サイズ 55mμ
PH2.7
オレイン酸 １部
ニトロセルロース 13部
ポリウレタン ７部
ポリイソシアネート ８部
α−Al2O3 ３部
メチルエチルケトン 150部
シクロヘキサノン 150部
比較例 １
実施例１のカーボンブラツクを下記のカーボン
ブラツクに代える以外は同様にしてサンプルNo.２
〜No.４を得た。なお、カレンダー条件を調整して
サンプルNo.１と同じ表面性（光沢度）を与える様
にした。
サンプルNo.２ 「＃2200B」三菱化成製（サイ
ズ18mμ、PH3.0）
サンプルNo.３ 「シーストＶ」東海電極製（サ
イズ56mμ、PH7.0）
サンプルNo.４ 「Printex25」デグサ製（サイ
ズ56mμ、PH9.5）
実施例 ２
実施例１に於てカーボンブラツクを
「Raven16」（コロンビアンカーボン製サイズ
70mμ、PH5.1）に代える以外同様にしてサンプル
No.５を得た。
サンプルNo.１〜No.５の評価結果を第１表に示
す。
The present invention relates to a magnetic recording medium, and particularly to a magnetic recording medium having improved magnetic orientation and durability. Conventionally, carbon black has been added to magnetic layers to prevent static electricity. However, sufficient carbon black μm has not yet been found. A magnetic recording medium must be designed to improve the orientation of the magnetic material from the viewpoint of electromagnetic conversion characteristics. At the same time, the magnetic layer is also required to have high durability. These requirements are more strongly required for precision tapes such as video tapes and memory tapes than for audio tapes. Therefore, an object of the present invention is to provide a magnetic recording medium having excellent magnetic orientation and durability. In order to satisfy the above characteristics, there is a method of examining the abrasive added to the magnetic layer, binder composition, magnetic material, etc., dispersion technology, and surface forming conditions of the magnetic layer. It has been found that by selecting a carbon black which is used as a preventive material, the above object is achieved.
That is, the present invention relates to a magnetic recording material comprising a non-magnetic support and a magnetic layer provided thereon, the magnetic layer containing carbon black having an average primary particle size of greater than 30 mμ and a pH of less than 6. . An important point in the present invention is that the average primary particle size of carbon black is larger than 30 mμ, particularly preferably 50 mμ or more, and more preferably
It is 50 mμ to 150 mμ. If the particle size is small,
The durability of the magnetic layer is insufficient, and large ones are difficult to obtain commercially. Another important point of the present invention is that the carbon black has a pH of less than 6,
Particularly preferably less than 4. If the PH is higher than this, the orientation will be poor and the effects of the present invention will not be obtained. Examples of carbon blacks that can be used in the present invention include "Raven14" and "Raven16" manufactured by Columbia Carbon, "SPecial Black10" and "SPecial Black25 (2/2) manufactured by Degussa.
0)" etc. These carbon blacks are 2
Can be used in combination of more than one species. The amount of carbon black added is 1 per 100 parts by weight of the magnetic material.
~20 parts by weight, especially 3 to 15 parts by weight. If the amount added is too small, the antistatic effect will be reduced, and if the amount added is too large, the degree of filling of the magnetic material will decrease and the electromagnetic conversion characteristics will deteriorate. Examples of magnetic materials include γ-Fe 2 O 3 and FeOx (1.33<x
<1.5), CrO 2 , Co-added γ-Fe 2 O 3 , Co-added FeOx
(1.33<x<1.5), tabular barium ferrite,
Ordinary ferromagnetic powders such as Fe-Co-Ni alloy powder and Fe-Zn alloy powder can be used. These magnetic materials can be used alone or in combination. The shape of the magnetic material is not particularly limited, and may be granular, acicular, spindle, or the like. As the binder, vinyl chloride-vinyl acetate copolymer, cellulose derivative (for example, nitrocellulose), polyurethane, nitrile-butadiene rubber, styrene-butadiene rubber, polyester, polyamide, polyisocyanate, etc. can be used. The magnetic layer of the present invention includes fatty acids, fatty acid esters, fatty amides, sorbitan fatty acid esters,
Liquid lubricants such as liquid paraffin, silicone oil, and fluorine oil; Abrasives such as Cr 2 O 3 , alumina, garnet, and α-Fe 2 O 3 ; Dispersants such as lecithin and sodium oleate; Metallic soap, dibutyltin Stabilizers such as dicarboxylates; plasticizers such as dibutyl phthalate and tricresyl phosphate; solid lubricants such as graphite and MoS 2 can be included. Examples of the support coated with the magnetic layer include polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide, and vinyl chloride films. A back layer may be applied to the support if necessary. The smoothness of both sides of the support can also be varied. Furthermore, on one side of the support (the surface opposite to the magnetic layer), before or after applying the magnetic layer,
A lubricant or surfactant can be applied. The composition, method, etc. for manufacturing the magnetic recording medium of the present invention are described in Japanese Patent Publication No. 56-26980. The present invention will be specifically explained below based on examples. In the examples, "parts" indicate "parts by weight." Example 1 A magnetic coating liquid was prepared by dispersing the following composition in a ball mill, and coated on a 15μ thick polyethylene terephthalate film to a dry thickness of 5μ. The magnetic field orientation treatment was carried out in the coating length direction using a solenoid when the magnetic layer was not yet dry. After the surface molding treatment of the magnetic layer, the tape was cut into 1/2 inch pieces to obtain a VHS videotape (sample No. 1). Co-added γ-Fe 2 O 3 100 parts Carbon black 5 parts “Raven14” manufactured by Columbia Carbon Average primary particle size 55 mμ PH2.7 Oleic acid 1 part Nitrocellulose 13 parts Polyurethane 7 parts Polyisocyanate 8 parts α-Al 2 O 3 3 parts Methyl ethyl ketone 150 parts Cyclohexanone 150 parts Comparative Example 1 Sample No. 2 was prepared in the same manner as in Example 1 except that the carbon black shown below was replaced.
~No.4 was obtained. Note that the calender conditions were adjusted to give the same surface properties (gloss) as sample No. 1. Sample No. 2 "#2200B" manufactured by Mitsubishi Kasei (size 18 mμ, PH 3.0) Sample No. 3 "Seest V" manufactured by Tokai Electrode (size 56 mμ, PH 7.0) Sample No. 4 "Printex 25" manufactured by Degussa (size 56 mμ) , PH9.5) Example 2 In Example 1, the carbon black was “Raven16” (Colombian carbon size)
70mμ, PH5.1)
I got No.5. Table 1 shows the evaluation results for samples No. 1 to No. 5.
【表】
本発明によるサンプルNo.１に対し、粒子サイズ
は同じでPHの異なるカーボンブラツクを用いたサ
ンプルNo.３、No.４は角型比の点で大幅に劣つてお
り、ドロツプアウト増加率の点でもやや劣つてい
る。
サンプルNo.２はサンプルNo.１とほぼ同等のPH
で、粒子サイズの小さなカーボンブラツクを用い
たものであるが、ドロツプアウト増加率が大幅に
劣つている。ドロツプアウト分析の結果、増加し
たドロツプアウトはそのほとんどが磁性層の削れ
による付着であつた。また、角型比がサンプルNo.
１より多少劣つているが、これはカーボンブラツ
クの粒子サイズが小さいので凝集性がサンプルNo.
１より大であるためと推定される。
サンプルNo.５は本発明によるもう一つの実施例
サンプルであるがほぼサンプルNo.１に近い特性を
有している。
サンプルNo.３、No.４の耐久性がサンプルNo.１よ
り劣る理由として、本発明者らは以下のように考
えている。即ち、PHが低いカーボンブラツクを用
いるとバインダーとの濡れがよく分散性に優れて
いる為、磁性体の配向性が良くなり、かつ磁性層
の緻密性が増すため、耐久性のある磁性層が得ら
れる。しかし、PHが高い場合はこれと逆の関係に
なる。
評価法の概略を以下に記す。角型比は振動試料
磁束計にて外部磁界2000Oeの下でテープ長さ方
向のＢ−Ｈカーブより定法通りBr／Bm比で表わ
した。
塗膜耐久性を示すドロツプアウト増加率は、未
走行テープを、記録／再生して求めた初回ドロツ
プアウト数（Do）と、VHS型VTRにて200パス
走行させた後に記録／再生して求めたドロツプア
ウト(D)よりＤ／Doで定義した。
カーボンブラツクのPHはJIS「K6221」またはこ
れに準ずる方法で測定する。
カーボンブラツクの平均一次粒子サイズは電子
顕微鏡写真からの算術的測定、またはこれに準ず
る方法による直径である。[Table] Compared to Sample No. 1 according to the present invention, Samples No. 3 and No. 4 using carbon black with the same particle size but different pH are significantly inferior in terms of squareness ratio, and dropout increase rate. It is also slightly inferior in terms of Sample No. 2 has almost the same pH as sample No. 1
This uses carbon black with a small particle size, but the dropout increase rate is significantly lower. As a result of dropout analysis, it was found that most of the increased dropouts were due to adhesion due to abrasion of the magnetic layer. Also, the squareness ratio is the sample No.
Although it is slightly inferior to Sample No. 1, the particle size of carbon black is smaller, so the cohesiveness is better than Sample No. 1.
This is presumed to be because it is larger than 1. Sample No. 5 is another example sample according to the present invention, but has characteristics almost similar to sample No. 1. The present inventors believe that the reason why the durability of samples No. 3 and No. 4 is inferior to that of sample No. 1 is as follows. In other words, when carbon black with a low pH is used, it has good wettability with the binder and excellent dispersibility, which improves the orientation of the magnetic material and increases the density of the magnetic layer, resulting in a durable magnetic layer. can get. However, when the pH is high, the relationship is reversed. An outline of the evaluation method is described below. The squareness ratio was expressed as the Br/Bm ratio according to the standard method using a B-H curve in the tape length direction under an external magnetic field of 2000 Oe using a vibrating sample magnetometer. The dropout increase rate, which indicates paint film durability, is determined by the number of initial dropouts (Do) obtained by recording/playing an unrun tape, and the dropout obtained by recording/playing after running 200 passes on a VHS-type VTR. From (D), it was defined as D/Do. The PH of carbon black is measured using JIS "K6221" or a method similar to this. The average primary particle size of carbon black is the diameter determined by an arithmetic measurement from an electron micrograph or an equivalent method.
Claims (1)
記録体に於て、該磁性層は、30μmより大きい平
均一次粒子サイズであつてPHが６未満のカーボン
ブラツクを含有することを特徴とする磁気記録
体。1. A magnetic recording material comprising a magnetic layer coated on a non-magnetic support, characterized in that the magnetic layer contains carbon black with an average primary particle size of more than 30 μm and a pH of less than 6. magnetic recording medium.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57129778A JPS5919234A (en) | 1982-07-26 | 1982-07-26 | Magnetic recording body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57129778A JPS5919234A (en) | 1982-07-26 | 1982-07-26 | Magnetic recording body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5919234A JPS5919234A (en) | 1984-01-31 |
| JPH0479057B2 true JPH0479057B2 (en) | 1992-12-14 |
Family
ID=15017981
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57129778A Granted JPS5919234A (en) | 1982-07-26 | 1982-07-26 | Magnetic recording body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5919234A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS613318A (en) * | 1984-06-15 | 1986-01-09 | Hitachi Maxell Ltd | Magnetic recording medium |
| KR880009340A (en) * | 1987-02-14 | 1988-09-14 | 나가이 아쯔시 | Magnetic recording medium and manufacturing method thereof |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS48101908A (en) * | 1972-04-07 | 1973-12-21 | ||
| JPS5023605A (en) * | 1973-06-29 | 1975-03-13 | ||
| JPS5092101A (en) * | 1973-12-14 | 1975-07-23 | ||
| JPS5228201A (en) * | 1975-08-28 | 1977-03-03 | Toshiba Corp | Tuner circuit |
| JPS5297709A (en) * | 1977-02-18 | 1977-08-16 | Hitachi Maxell | Magnetic recording material |
| JPS5297710A (en) * | 1977-02-18 | 1977-08-16 | Hitachi Maxell | Magnetic recording material |
| JPS5347806A (en) * | 1977-06-29 | 1978-04-28 | Hitachi Maxell | Magnetic recording material |
| JPS5651027A (en) * | 1979-10-02 | 1981-05-08 | Hitachi Maxell Ltd | Magnetic recording medium |
| JPS5651025A (en) * | 1979-10-02 | 1981-05-08 | Hitachi Maxell Ltd | Magnetic recording medium |
| JPS5680826A (en) * | 1979-11-30 | 1981-07-02 | Sony Corp | Magnetic recording medium |
| JPS5794928A (en) * | 1980-12-03 | 1982-06-12 | Matsushita Electric Ind Co Ltd | Magnetic recording medium |
| JPS58133626A (en) * | 1982-02-04 | 1983-08-09 | Fuji Photo Film Co Ltd | Magnetic recording body |
-
1982
- 1982-07-26 JP JP57129778A patent/JPS5919234A/en active Granted
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS48101908A (en) * | 1972-04-07 | 1973-12-21 | ||
| JPS5023605A (en) * | 1973-06-29 | 1975-03-13 | ||
| JPS5092101A (en) * | 1973-12-14 | 1975-07-23 | ||
| JPS5228201A (en) * | 1975-08-28 | 1977-03-03 | Toshiba Corp | Tuner circuit |
| JPS5297709A (en) * | 1977-02-18 | 1977-08-16 | Hitachi Maxell | Magnetic recording material |
| JPS5297710A (en) * | 1977-02-18 | 1977-08-16 | Hitachi Maxell | Magnetic recording material |
| JPS5347806A (en) * | 1977-06-29 | 1978-04-28 | Hitachi Maxell | Magnetic recording material |
| JPS5651027A (en) * | 1979-10-02 | 1981-05-08 | Hitachi Maxell Ltd | Magnetic recording medium |
| JPS5651025A (en) * | 1979-10-02 | 1981-05-08 | Hitachi Maxell Ltd | Magnetic recording medium |
| JPS5680826A (en) * | 1979-11-30 | 1981-07-02 | Sony Corp | Magnetic recording medium |
| JPS5794928A (en) * | 1980-12-03 | 1982-06-12 | Matsushita Electric Ind Co Ltd | Magnetic recording medium |
| JPS58133626A (en) * | 1982-02-04 | 1983-08-09 | Fuji Photo Film Co Ltd | Magnetic recording body |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5919234A (en) | 1984-01-31 |
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