JPH0232688B2 - - Google Patents
Info
- Publication number
- JPH0232688B2 JPH0232688B2 JP59032695A JP3269584A JPH0232688B2 JP H0232688 B2 JPH0232688 B2 JP H0232688B2 JP 59032695 A JP59032695 A JP 59032695A JP 3269584 A JP3269584 A JP 3269584A JP H0232688 B2 JPH0232688 B2 JP H0232688B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- back coat
- coat layer
- layer
- calendering
- 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
- 238000003490 calendering Methods 0.000 claims description 14
- 239000011230 binding agent Substances 0.000 claims description 7
- 239000003973 paint Substances 0.000 claims description 4
- 239000011248 coating agent Substances 0.000 claims description 3
- 238000001035 drying Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 239000000049 pigment Substances 0.000 claims description 3
- 239000003795 chemical substances by application Substances 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 4
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 4
- 230000005347 demagnetization Effects 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 239000006247 magnetic powder Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 description 2
- 239000006229 carbon black Substances 0.000 description 2
- 239000002270 dispersing agent Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000004381 surface treatment Methods 0.000 description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- 239000000020 Nitrocellulose Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- 239000003082 abrasive agent Substances 0.000 description 1
- 239000000654 additive 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
- 239000000919 ceramic Substances 0.000 description 1
- 229940090961 chromium dioxide Drugs 0.000 description 1
- IAQWMWUKBQPOIY-UHFFFAOYSA-N chromium(4+);oxygen(2-) Chemical compound [O-2].[O-2].[Cr+4] IAQWMWUKBQPOIY-UHFFFAOYSA-N 0.000 description 1
- AYTAKQFHWFYBMA-UHFFFAOYSA-N chromium(IV) oxide Inorganic materials O=[Cr]=O AYTAKQFHWFYBMA-UHFFFAOYSA-N 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- -1 etc. Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 239000001023 inorganic pigment Substances 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 229920001220 nitrocellulos Polymers 0.000 description 1
- 239000012860 organic pigment Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 239000004848 polyfunctional curative Substances 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000007420 reactivation Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
Landscapes
- Magnetic Record Carriers (AREA)
- Manufacturing Of Magnetic Record Carriers (AREA)
- Paints Or Removers (AREA)
Description
(産業上の利用分野)
本発明は、オーデイオ機器、ビデオ機器および
コンピユータ等に使用される磁気テープや磁気シ
ート等の磁気記録媒体の製造方法に関するもので
ある。
(従来例の構成とその問題点)
近年、この種の磁気記録媒体は高密度記録化に
伴い、短波長記録時における磁気記録媒体と磁気
ヘツドとの間の間隔損失を減少させるために、高
平滑な非磁性支持体を用いて高平滑な磁性層表面
を得ようとしている。ところが、高平滑な非磁性
支持体は走行性および耐久性に欠けるので、その
裏面にカーボンブラツク、炭酸カルシウム、硫酸
バリウムまたは酸化チタン等の無機粉末と樹脂結
合剤とからなるバツクコート層を形成していた。
しかしながら、バツクコート層を形成すること
により走行性は著しく改善されるが、無機粉末の
脱落が生じるためにドロツプアウトが増加し、さ
らに、バツクコート層の表面突起が裏写りするた
めに磁性層表面が荒れ、AM性変調ノイズが増加
する等の不都合が生じていた。
(発明の目的)
本発明は、上記従来例の欠点に鑑みてなされた
もので、走行性および耐久性に優れ、さらにノイ
ズが少ない磁気記録媒体を得ることができる磁気
記録媒体の製造方法を提供するものである。
(発明の構成)
上記目的を達成するために、本発明は、非磁性
支持体の一方の主面にバツクコート剤を塗布し乾
燥させてバツクコート層を形成した後に、非磁性
支持体の他方の主面に磁性塗料を塗布し乾燥させ
て磁性層を形成し、その後バツクコート層の表面
をカレンダ処理するようにしたもので、バツクコ
ート層にカレンダ処理を施すことにより、バツク
コート層表面の平滑性が向上し、磁性層表面への
裏写りを抑制することができるとともに、バツク
コート層が圧縮されて見掛密度が上がるのでその
機械的強度を向上させることができる。
(実施例の説明)
以下、本発明の実施例を詳細に説明する。
まず、非磁性支持体の一主面に顔料と結合剤と
からなるバツクコート剤を塗布し乾燥させてバツ
クコート層を形成する。このバツクコート剤は、
カーボンブラツク、グラフアイト、炭酸カルシウ
ム、硫酸バリウム、酸化チタン、アルミナ等の無
機顔料あるいは各種有機顔料の中から一種または
二種以上を、ニトロセルロース、ポリウレタン、
ポリエステル、塩ビ酢ビ共重合体、ポリイミド等
の結合剤中に分散させたもので、必要に応じて分
散剤、硬化剤等が加えられる。また、顔料の粒径
は1μm以下が好ましく、0.02〜0.5μmが最適であ
る。次に、非磁性支持体の他方の主面に磁性塗料
を塗布し乾燥させて磁性層を形成する。ここで用
いられる磁性塗料は磁性粉末と結合剤とからな
り、必要に応じて研磨材、分散剤、潤滑剤、硬化
剤等が加えられたもので、磁性粉末としては磁性
酸化鉄、二酸化クロム、金属磁性粉のいずれでも
よく、また結合剤としてはバツクコート剤と同様
のものが知られている。このようにして非磁性支
持体の表裏各面にバツクコート層および磁性層を
それぞれ形成した後に、バツクコート層の表面を
カレンダ処理する。ここでは、バツクコート層を
形成した非磁性支持体を加温条件下で対向するロ
ールの間に通すことにより加圧して表面処理を行
なつていて、この表処理に使用されるカレンダ
は、金属ロール、コツトンロール、樹脂ロール、
ガラスロール、セラミツクロール等を組み合わせ
て構成されている。また、カレンダ処理条件は、
ロールの組み合わせやカレンダ処理段数によつて
も異なるが、過剰なカレンダ処理はバツクコート
層の表面を傷め、その摩擦係数を上昇させるの
で、温度30〜90℃、圧力20〜200Kg/cm、速度10
〜200m/分が適当である。
次に、本発明の具体的な実施例を説明する。
実施例 1
非磁性支持体として厚さ10μmの巾広のベース
フイルムを用い、その一表面にバツクコート剤を
塗布・乾燥して厚さ1μmのバツクコート層を形成
した後、ベースフイルムの裏面にCo−γ−Fe2O3
と結合剤と必要に応じて加えられる添加剤とから
なる磁性塗料を塗布・乾燥して厚さ4μmの磁性層
を形成した。そして、4本の金属ロールで3本の
樹脂ロールを交互に挟んで処理段数6ニツプのカ
レンダを構成し、磁性層の表面が金属ロールに当
接するようにしてカレンダ処理を行なつた。この
磁性層のカレンダ処理条件は、温度80℃、圧力70
Kg/cm、速度100m/分であつた。次に、同じカ
レンダでバツクコート層の表面が金属ロールに当
接するようにしてカレンダ処理を行なつた。この
バツクコート層のカレンダ条件は、温度70℃、圧
力60Kg/cm、速度100m/分であつた。こうして
得られた巾広の磁性テープを1/2インチ巾に裁
断してビデオテープを作製した。
実施例 2
実施例1と同様に巾広のベースフイルムの表裏
各面にバツクコート層と磁性層を形成した後、2
本の金属ロールからなる処理段数1ニツプのカレ
ンダを構成し、バツクコート層と磁性層のカレン
ダ処理を同時に行なつた。この時のカレンダ処理
条件は、温度70℃、圧力50Kg/cm、速度100m/
分であつた。こうして得られた巾広の磁気テープ
を1/2インチ巾に裁断してビデオテープを作製
した。
比較例
実施例1と同様のビデオテープを、バツクコー
ト層のカレンダ処理を行なわずに形成した。
上記の実施例1、実施例2、比較例の各々の変
調ノイズ量、100回の通常走行時のドロツプアウ
ト数および虫食い減磁の有無をそれぞれ調べ、表
に示した。
(Industrial Application Field) The present invention relates to a method for manufacturing magnetic recording media such as magnetic tapes and magnetic sheets used in audio equipment, video equipment, computers, and the like. (Conventional structure and its problems) In recent years, with the trend toward higher density recording, this type of magnetic recording medium has been designed with a high Attempts are being made to obtain a highly smooth magnetic layer surface using a smooth non-magnetic support. However, since highly smooth non-magnetic supports lack runnability and durability, a back coat layer consisting of inorganic powder such as carbon black, calcium carbonate, barium sulfate or titanium oxide and a resin binder is formed on the back surface. Ta. However, although the runnability is significantly improved by forming a back coat layer, the dropout increases due to the inorganic powder falling off, and furthermore, the surface protrusions of the back coat layer show through, making the surface of the magnetic layer rough. Problems such as an increase in AM modulation noise occurred. (Objective of the Invention) The present invention has been made in view of the drawbacks of the above-mentioned conventional examples, and provides a method for manufacturing a magnetic recording medium that can obtain a magnetic recording medium that has excellent runnability and durability and has less noise. It is something to do. (Structure of the Invention) In order to achieve the above object, the present invention applies a back coat agent to one main surface of a non-magnetic support and dries it to form a back coat layer, and then coats the other main surface of the non-magnetic support with a back coat agent. A magnetic layer is formed by applying magnetic paint to the surface and drying it, and then the surface of the back coat layer is calendered. By calendering the back coat layer, the smoothness of the surface of the back coat layer is improved. In addition, since the back coat layer is compressed and its apparent density is increased, its mechanical strength can be improved. (Description of Examples) Examples of the present invention will be described in detail below. First, a back coat agent consisting of a pigment and a binder is applied to one main surface of a nonmagnetic support and dried to form a back coat layer. This back coat agent is
One or more inorganic pigments such as carbon black, graphite, calcium carbonate, barium sulfate, titanium oxide, alumina, or various organic pigments, nitrocellulose, polyurethane,
It is dispersed in a binder such as polyester, vinyl chloride/acetate copolymer, polyimide, etc., and a dispersant, curing agent, etc. are added as necessary. Further, the particle size of the pigment is preferably 1 μm or less, and optimally 0.02 to 0.5 μm. Next, a magnetic paint is applied to the other main surface of the non-magnetic support and dried to form a magnetic layer. The magnetic paint used here consists of magnetic powder and a binder, with abrasives, dispersants, lubricants, hardeners, etc. added as necessary.The magnetic powders include magnetic iron oxide, chromium dioxide, Any metal magnetic powder may be used, and the same binders as back coating agents are known. After forming a back coat layer and a magnetic layer on each of the front and back surfaces of the nonmagnetic support in this manner, the surfaces of the back coat layers are calendered. Here, surface treatment is carried out by applying pressure by passing the non-magnetic support on which a back coat layer has been formed between opposing rolls under heated conditions, and the calender used for this surface treatment is , cotton roll, resin roll,
It is composed of a combination of glass rolls, ceramic rolls, etc. In addition, the calendar processing conditions are
Although it varies depending on the combination of rolls and the number of calendering stages, excessive calendering damages the surface of the back coat layer and increases its friction coefficient.
~200m/min is appropriate. Next, specific examples of the present invention will be described. Example 1 A wide base film with a thickness of 10 μm was used as a non-magnetic support, and a back coat agent was coated on one surface of the base film and dried to form a back coat layer with a thickness of 1 μm. Co-coat was applied to the back surface of the base film. γ − Fe2O3
A magnetic coating consisting of a binder and additives added as necessary was applied and dried to form a magnetic layer with a thickness of 4 μm. Then, a calender with 6 processing stages was constructed by sandwiching three resin rolls alternately between four metal rolls, and the calender treatment was performed with the surface of the magnetic layer in contact with the metal rolls. The calendering conditions for this magnetic layer are a temperature of 80°C and a pressure of 70°C.
kg/cm, and the speed was 100 m/min. Next, calendering was performed using the same calender so that the surface of the back coat layer was in contact with a metal roll. The calendering conditions for this back coat layer were a temperature of 70°C, a pressure of 60 kg/cm, and a speed of 100 m/min. The wide magnetic tape thus obtained was cut into 1/2 inch width pieces to produce video tapes. Example 2 After forming a back coat layer and a magnetic layer on the front and back surfaces of a wide base film in the same manner as in Example 1,
A calender with one processing stage and one nip was constructed of a metal roll, and the back coat layer and the magnetic layer were calendered simultaneously. The calendering conditions at this time were: temperature 70℃, pressure 50Kg/cm, speed 100m/cm.
It was hot in minutes. The wide magnetic tape thus obtained was cut into 1/2 inch width pieces to produce video tapes. Comparative Example A videotape similar to Example 1 was made without calendering of the backcoat layer. The amount of modulation noise, the number of dropouts during 100 normal runs, and the presence or absence of moth-eaten demagnetization were investigated for each of the above-mentioned Example 1, Example 2, and Comparative Example, and are shown in the table.
【表】
なお、表において、変調ノイズ量は、VHS方
式VTR,NV−8200(松下電器(株)製)を用い、
4MHzの単調信号を記録・再生し、4MHz+20kHz
における変調ノイズ量をスペクトラムアナライザ
により測定した。ドロツプアウト数は、VHS方
式VTR,NV−8200を用い、映像再生信号の瞬
間的な欠落(15μs,16dB)をドロツプアウトカ
ウンターで測定し、1分間あたりの平均値を示し
た。虫食い減磁は、VHS方式VTR,NV−8200
を用い、映像再勢信号のエンベロープをオシロス
コープで観測し、3dB以上の欠落の本数を数え
た。
上記の表からも明らかなように、本発明による
実施例1および2は、バツクコート層の表面をカ
レンダ処理して平滑化することにより、磁性層へ
の裏写りを抑制するとともにバツクコート層の機
械的強度を向上させることができるので、従来の
ようにバツクコート層のカレンダ処理を行なわな
い比較例に比べて、変調ノイズ、ドロツプアウト
および虫食い減磁をそれぞれ著しく低減すること
ができる。
なお、実施例として磁気テープについて説明し
たが、磁気テープだけでなく磁気シートおよび磁
気カード等の他の磁気記録媒体にも応用できるこ
とはいうまでもない。
(発明の効果)
以上説明したように、本発明によれば、磁気記
録媒体の変調ノイズ、ドロツプアウトおよび虫食
い減磁を著しく低減することができるので、走行
性、耐久性および電磁変換特性の優れた磁気記録
媒体を容易に製造することができ、その実用上の
価値が大なるものである。[Table] In the table, the amount of modulation noise is calculated using a VHS system VTR, NV-8200 (manufactured by Matsushita Electric Co., Ltd.).
Record and play back 4MHz monotone signal, 4MHz+20kHz
The amount of modulation noise was measured using a spectrum analyzer. The number of dropouts was determined by measuring momentary dropouts (15 μs, 16 dB) in the video playback signal with a dropout counter using a VHS VTR, NV-8200, and the average value per minute was shown. Moth-eaten demagnetization is VHS method VTR, NV-8200
The envelope of the video reactivation signal was observed using an oscilloscope, and the number of dropouts of 3 dB or more was counted. As is clear from the table above, in Examples 1 and 2 according to the present invention, by smoothing the surface of the back coat layer by calendering, it is possible to suppress the transfer to the magnetic layer and to improve the mechanical strength of the back coat layer. Since the strength can be improved, modulation noise, dropout, and moth-eaten demagnetization can be significantly reduced compared to a comparative example in which the back coat layer is not calendered as in the past. Incidentally, although a magnetic tape has been described as an example, it goes without saying that the present invention can be applied not only to magnetic tape but also to other magnetic recording media such as magnetic sheets and magnetic cards. (Effects of the Invention) As explained above, according to the present invention, it is possible to significantly reduce modulation noise, dropout, and moth-eaten demagnetization of a magnetic recording medium. Magnetic recording media can be easily produced and have great practical value.
Claims (1)
剤からなるバツクコート剤を塗布し乾燥させてバ
ツクコート層を形成した後に、前記非磁性支持体
の他方の主面に磁性塗料を塗布し乾燥させて磁性
層を形成し、その後前記バツクコート層の表面を
カレンダ処理することを特徴とする磁気記録媒体
の製造方法。1 After applying a back coating agent consisting of a pigment and a binder to one main surface of a non-magnetic support and drying it to form a back coat layer, applying a magnetic paint to the other main surface of the non-magnetic support and drying it. 1. A method of manufacturing a magnetic recording medium, comprising forming a magnetic layer using a magnetic recording medium, and then calendering the surface of the back coat layer.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP59032695A JPS60179940A (en) | 1984-02-24 | 1984-02-24 | Production of magnetic recording medium |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP59032695A JPS60179940A (en) | 1984-02-24 | 1984-02-24 | Production of magnetic recording medium |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS60179940A JPS60179940A (en) | 1985-09-13 |
JPH0232688B2 true JPH0232688B2 (en) | 1990-07-23 |
Family
ID=12365985
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP59032695A Granted JPS60179940A (en) | 1984-02-24 | 1984-02-24 | Production of magnetic recording medium |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS60179940A (en) |
-
1984
- 1984-02-24 JP JP59032695A patent/JPS60179940A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPS60179940A (en) | 1985-09-13 |
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