JPH0782632B2 - Magnetic recording medium - Google Patents
Magnetic recording mediumInfo
- Publication number
- JPH0782632B2 JPH0782632B2 JP61027114A JP2711486A JPH0782632B2 JP H0782632 B2 JPH0782632 B2 JP H0782632B2 JP 61027114 A JP61027114 A JP 61027114A JP 2711486 A JP2711486 A JP 2711486A JP H0782632 B2 JPH0782632 B2 JP H0782632B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- protrusions
- recording medium
- protrusion
- support
- 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
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- Compositions Of Macromolecular Compounds (AREA)
- Magnetic Record Carriers (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、オーディオ機器，ビデオ機器およびコンピュ
ータ等に用いられる磁気テープ，磁気シート等の磁気記
録媒体に関するものである。Description: TECHNICAL FIELD The present invention relates to a magnetic recording medium such as a magnetic tape or a magnetic sheet used in audio equipment, video equipment, computers and the like.
従来の技術 近年これらの各磁気記録媒体は高密度記録に向かい、高
周波記録・再生時の間隔損失を減少させるため磁性層表
面はますます高平滑化している。磁性層は非磁性支持体
の裏移りにより表面粗さが悪化する。2. Description of the Related Art In recent years, each of these magnetic recording media is moving toward high-density recording, and the surface of the magnetic layer is becoming more and more smooth in order to reduce the distance loss during high-frequency recording / reproduction. The surface roughness of the magnetic layer deteriorates due to the offset of the non-magnetic support.
このため平滑性の高い非磁性支持体を用いて表面粗さの
裏移りをなくす方法が採られている。更に走行，耐久性
を確保するため支持体上の磁性面とは反対の面にバック
コート層を付与する手段が知られている。Therefore, a method of eliminating the set-off of the surface roughness by using a non-magnetic support having high smoothness is adopted. Further, a means for providing a back coat layer on the surface of the support opposite to the magnetic surface is known in order to secure running and durability.
又、平滑な非磁性支持体は滑り性が悪く非磁性支持体及
び磁気記録媒体の製造工程での作業性を確保するため、
非磁性支持体中に無機質あるいは有機質の微粒子を添化
する方法が知られている。In addition, a smooth non-magnetic support has poor slidability, and in order to ensure workability in the manufacturing process of the non-magnetic support and the magnetic recording medium,
A method is known in which inorganic or organic fine particles are added to a non-magnetic support.
発明が解決しようとする問題点 このように非磁性支持体の表面をどんどん平滑にし裏移
り現象を低減し、磁性面の表面粗さを向上させていく
と、磁性面の摩擦係数が上昇しさらに非磁性支持体の滑
り性が悪いため製造工程での作業性を悪化するという問
題点が発生している。本発明はこのような問題を解決す
るもので磁性層の良好な表面性を維持しつつ安定な走
行，耐久性を得ることのできる磁気記録媒体を提供する
ことを目的とするものである。Problems to be Solved by the Invention As described above, when the surface of the non-magnetic support is gradually smoothed to reduce the set-off phenomenon and the surface roughness of the magnetic surface is improved, the friction coefficient of the magnetic surface is further increased. Since the non-magnetic support has poor slipperiness, the workability in the manufacturing process is deteriorated. An object of the present invention is to solve such problems and to provide a magnetic recording medium capable of obtaining stable running and durability while maintaining good surface properties of the magnetic layer.
問題点を解決するための手段 本発明は上記問題点を解決するために、上面に突起の径
が0.05〜0.20μｍ、高さが0.01〜0.10μｍ、突起の密度
が１μm2当たり0.2〜20個、支持体の被覆率が0.6〜４％
である半球状の突起を持つ非磁性支持体の反対面上に磁
性層を設け、前記非磁性支持体の突起の形状が磁性面上
に転写すものである。Means for Solving the Problems In order to solve the above problems, the present invention has a protrusion having a diameter of 0.05 to 0.20 μm, a height of 0.01 to 0.10 μm, and a protrusion density of 0.2 to 20 per 1 μm 2. , The coverage of the support is 0.6-4%
A magnetic layer is provided on the opposite surface of the non-magnetic support having hemispherical projections, and the shape of the projections of the non-magnetic support is transferred onto the magnetic surface.
作 用 上記の構造により従来に比べ電磁変換特性を劣化させる
ことなく磁性層の摩擦係数が著しく低減される。Operation The structure described above significantly reduces the friction coefficient of the magnetic layer without deteriorating the electromagnetic conversion characteristics as compared with the conventional structure.
実施例 以下、本発明の実施例を図面を用いて説明する。図に示
すように非磁性支持体２上に突起３を形成し、これによ
り磁性層１に突起形状を転写する。このように、この凹
状のへこみを形成することにより、真実接触面積の低
下、あるいは空気層の発生等により、摩擦係数が低減さ
れる。Embodiments Embodiments of the present invention will be described below with reference to the drawings. As shown in the figure, the protrusion 3 is formed on the non-magnetic support 2, and the protrusion shape is transferred to the magnetic layer 1. By thus forming the concave depression, the friction coefficient is reduced due to the reduction of the true contact area or the generation of the air layer.
突起３の径が0.20μｍあるいは高さが0.1μｍより大き
いと磁性面上に“うねり”が発生し変調ノイズが発生す
る。突起の数が20個／μm2以上ならば出力の低下が起こ
る。If the diameter of the projection 3 is 0.20 μm or the height is larger than 0.1 μm, “waviness” occurs on the magnetic surface and modulation noise occurs. If the number of protrusions is 20 / μm 2 or more, the output will decrease.
また、突起３の径が0.05μｍより小さい、高さが0.01μ
ｍより低い、あるいは突記の密度が0.2個／μm2より少
ないと十分な裏移り現象を起こさず、摩擦係数が低減さ
れない。Moreover, the diameter of the protrusion 3 is smaller than 0.05 μm, and the height is 0.01 μm.
If it is lower than m or the density of protrusions is less than 0.2 pieces / μm 2 , the set-off phenomenon does not occur sufficiently and the friction coefficient is not reduced.
本実施例に用いられる非磁性支持体２は、フィルム内部
に表面の突起の原因となる無機質微粒子，有機質微粒
子，及び重合残査からなる内在粒子を事実上含まない平
滑なポリエステル，ポリアミド，ポリイミド等の延伸フ
ィルムの表面の両面または片面に島状に有機物，無機物
の突起を設けたものである。突起３は、 （１） シリコーン樹脂，フッ素樹脂等を上記延伸フィ
ルム上に薄く塗布し表面張力の違いにより島状の突起を
設ける方法で、上記樹脂にフィラーを添加してもよい、 （２） シリカ，カーボン,2硫化モリブデン等の無機物
を蒸着法，スパッタ法等により上記延伸フィルム上に付
着させる方法、 （３） シランカップリング剤、チタンカップリング剤
等を上記延伸フィルム上で加水分解し付ける方法等によ
り設けられる。The non-magnetic support 2 used in this example is a smooth polyester, polyamide, polyimide, etc. which is virtually free of inorganic fine particles, organic fine particles, and internal particles composed of polymerization residues that cause surface protrusions inside the film. Of the stretched film, the organic and inorganic projections are provided in an island shape on both sides or one side of the stretched film. The protrusion 3 is (1) a method in which a silicone resin, a fluororesin or the like is thinly applied on the stretched film and island-shaped protrusions are provided due to a difference in surface tension, and a filler may be added to the resin. A method of depositing an inorganic substance such as silica, carbon or molybdenum disulfide on the stretched film by vapor deposition, sputtering, etc. (3) Hydrolyzing a silane coupling agent, titanium coupling agent, etc. on the stretched film It is provided by a method or the like.
この突起３を設けた後にさらに延伸処理を行ってもよ
い。こうして作成された島状の突起３を持つ非磁性支持
体２を用い、片面にのみ突起３を設けた場合は突起を持
たない平滑な面上に、両面に突起を設けた場合は任意の
面に磁性層１を設け、磁性面に裏移りにより突起の形状
を転写する。このため磁性面は部分的に凹状のへこみを
持つ非常に平滑な面が形成され、部分的なへこみは充分
小さく数が少ないため事実上電磁変換特性は損なわれ
ず、摩擦係数は著しく減少される。A drawing process may be further performed after providing the protrusion 3. The non-magnetic support 2 having the island-shaped projections 3 thus created is used, and when the projections 3 are provided on only one side, a smooth surface having no projections is provided. When the projections are provided on both sides, any surface is provided. The magnetic layer 1 is provided on the magnetic recording medium and the shape of the protrusion is transferred to the magnetic surface by offsetting. For this reason, the magnetic surface is formed as a very smooth surface having a concave dent partially, and since the partial dent is small enough and the number is small, the electromagnetic conversion characteristics are not actually impaired and the friction coefficient is remarkably reduced.
次に、磁気記録媒体の製造方法を磁気テープを例として
説明する。Next, a method of manufacturing a magnetic recording medium will be described by using a magnetic tape as an example.
まず磁性層１の形成は、以下のようにして行う。磁性粉
末、前記の研磨材、必要に応じて添加される帯電防止剤
等の無機顔料、及び結合剤，分散剤，潤滑材等を有機溶
剤とともに、混合機にて十分混合分散し所望の成分比を
有する磁性塗布液を作成する。First, the magnetic layer 1 is formed as follows. Magnetic powder, the above abrasives, inorganic pigments such as antistatic agents added as necessary, and binders, dispersants, lubricants, etc. together with an organic solvent are thoroughly mixed and dispersed in a mixer to obtain a desired component ratio. To prepare a magnetic coating solution.
ここで、用いる磁性粉末としては、磁性酸化鉄，二酸化
クロム，金属磁性粉等のいずれでもよい。帯電防止剤と
しては、カーボンブラック，グラファイト粒子がある。
研磨材としては、αアルミナ，酸化チタン，ベンガラ，
酸化クロム,SiC等が用いられる。結合剤としては、ポリ
ウレタン樹脂，塩ビ樹脂，エポキシ樹脂，フェノール樹
脂，セルロース樹脂，ポリエステル樹脂等があり、これ
らの単独もしくは、２種以上の組合わせが、用いられ
る。分散剤としては、高級脂肪酸，高級アルコール，リ
ン酸エステル，グリセロリン等がある。潤滑剤として
は、シリコン樹脂，高級脂肪酸エステル等がある。硬化
剤としては、イソシアネート，ポリアミン、ポリアミド
等がある。有機溶剤としては、メチルエチルケトン，メ
チルイソブチルケトン，トルエン，シクロヘキサノン，
酢酸エチル，酢酸ブチル等がある。The magnetic powder used here may be magnetic iron oxide, chromium dioxide, magnetic metal powder, or the like. Antistatic agents include carbon black and graphite particles.
Abrasive materials include α-alumina, titanium oxide, red iron oxide,
Chromium oxide, SiC, etc. are used. Examples of the binder include polyurethane resin, vinyl chloride resin, epoxy resin, phenol resin, cellulose resin, polyester resin and the like, and these may be used alone or in combination of two or more kinds. Examples of the dispersant include higher fatty acid, higher alcohol, phosphate ester, glyceroline and the like. Examples of the lubricant include silicone resin and higher fatty acid ester. Examples of the curing agent include isocyanate, polyamine, and polyamide. Organic solvents include methyl ethyl ketone, methyl isobutyl ketone, toluene, cyclohexanone,
Examples include ethyl acetate and butyl acetate.
これらの組成物を溶剤とともに混合機にて十分混合分散
して、所望の成分比を有する磁性塗料を作成する。混合
機としては、ボールミル，サンドミル，ディゾルバー，
アトライター，高速ミキサー，ニーダー，ヘシェルミ
ル，プラネタリウムミキサー,3本ロール等を使えば良
い。These compositions are thoroughly mixed and dispersed with a solvent in a mixer to prepare a magnetic paint having a desired component ratio. As a mixer, ball mill, sand mill, dissolver,
Attritor, high speed mixer, kneader, heschel mill, planetarium mixer, 3 rolls, etc. can be used.
こうして得られた磁性塗料を上記非磁性支持体２上に塗
布する。塗布方式としては、ドクターブレード方式，グ
ラビア方式、リバースロール方式等を用いる。塗布直
後、塗膜の平滑性をさらに上げるため、スマーザーを接
触させても良い。これにはバースムーザー，ワイヤース
ムーザー，フィルムスムーザー等を用いる。The magnetic coating material thus obtained is applied onto the non-magnetic support 2. As a coating method, a doctor blade method, a gravure method, a reverse roll method, or the like is used. Immediately after coating, a smarter may be contacted to further improve the smoothness of the coating film. A bar smoother, wire smoother, film smoother, etc. are used for this.
乾燥直前に塗布膜中の磁性仮名を適当な配向状態にする
ため、磁場配向装置またはランダマイザーを用いて配向
処理を行う。この後、塗膜を乾燥して溶剤を離脱させ
る。Immediately before drying, in order to bring the magnetic pseudonym in the coating film into an appropriate orientation, an orientation treatment is performed using a magnetic field orientation device or a randomizer. After this, the coating film is dried to remove the solvent.
塗布，乾燥した広幅の磁性層表面をさらに平滑にするた
めスーパーカレンダにて表面加工処理を行う。カレンダ
条件としては、温度50−100℃、圧力50−400kg/cm、速
度50−400m/分が望ましい。こうして得られた塗膜をジ
ャンボロールに巻きとると表面粗さの裏移り現象により
ベースフィルムの表面粗さが磁性面に転写される。この
転写を促進するためジャンボロールを加熱処理しても良
い。巻きとりテンションは10−200kg/cm2が適当であ
る。In order to further smooth the surface of the coated and dried wide magnetic layer, surface treatment is performed with a super calendar. As calendering conditions, a temperature of 50-100 ° C, a pressure of 50-400kg / cm, and a speed of 50-400m / min are desirable. When the coating film thus obtained is wound on a jumbo roll, the surface roughness of the base film is transferred to the magnetic surface due to the offset phenomenon of the surface roughness. The jumbo roll may be heat-treated to accelerate this transfer. A winding tension of 10-200 kg / cm 2 is appropriate.
（実施例１） フィルム内部に突起の原因となる粒子類を含まない厚さ
15μｍの高平滑なベースフィルムの両面上に径が0.1μ
ｍ高さが0.05μｍで突起密度が５個／μm2の半球状の突
起３を設けた。この非磁性支持体２上に磁性塗料を５μ
ｍ厚で塗布し、配向・乾燥・カレンダ処理後、ジャンボ
ロールに巻きとった。３時間の放置でベースフィルムの
形状が磁性面に転写した。このジャンボロールを1/2イ
ンチ幅に細断してビデオテープを作製した。(Example 1) Thickness that does not include particles that cause protrusions inside the film
The diameter is 0.1μ on both sides of the 15μm high smooth base film.
Hemispherical protrusions 3 having a height of 0.05 μm and a protrusion density of 5 protrusions / μm 2 were provided. Apply 5μ of magnetic paint on this non-magnetic support 2.
It was applied in a thickness of m, oriented, dried, and calendered, and then wound on a jumbo roll. After standing for 3 hours, the shape of the base film was transferred to the magnetic surface. The jumbo roll was shredded into 1/2 inch widths to produce a video tape.
（実施例２） 実施例１のうち突起３の径が0.2μm,高さが0.10μｍで
突起密度が0.2個／μm2であり膜厚が15μｍの非磁性支
持体２上を用いた後は実施例１と同様にしてビデオテー
プを作製した。(Example 2) After using the non-magnetic support 2 of Example 1 having a diameter of the protrusions 3 of 0.2 μm, a height of 0.10 μm, a protrusion density of 0.2 / μm 2 and a film thickness of 15 μm, A video tape was produced in the same manner as in Example 1.
（実施例３） 実施例１のうち突起３の径が0.05μm,高さが0.02μｍで
突起密度が20個／μm2であり膜厚が15μｍの非磁性支持
体２上を用いた後は実施例１と同様にして、ビデオテー
プを作製した。(Example 3) After using the non-magnetic support 2 having a diameter of the projections 3 of 0.05 μm, a height of 0.02 μm, a projection density of 20 pieces / μm 2 and a film thickness of 15 μm in Example 1, A video tape was produced in the same manner as in Example 1.
（比較例１） 実施例１のうち突起３の径が0.01μm,高さが0.01μｍで
突起密度が10個／μm2であり膜厚が15μｍの非磁性支持
体２上を用いた後は実施例１と同様にしてビデオテープ
を作製した。(Comparative Example 1) In Example 1, after using the non-magnetic support 2 having a diameter of the protrusions 3 of 0.01 μm, a height of 0.01 μm, a protrusion density of 10 pieces / μm 2 and a film thickness of 15 μm, A video tape was produced in the same manner as in Example 1.
（比較例２） 実施例１のうち突起３の径が0.30μm,高さが0.15μｍで
突起密度が１個／μm2であり膜厚が15μｍの非磁性支持
体２上を用いた後は実施例１と同様にしてビデオテープ
を作製した。(Comparative Example 2) After using the non-magnetic support 2 of Example 1 having a diameter of the protrusions of 0.30 μm, a height of 0.15 μm, a protrusion density of 1 / μm 2 and a film thickness of 15 μm, A video tape was produced in the same manner as in Example 1.
（比較例３） 実施例１のうち突起の径が0.10μm,高さが0.06μｍで突
起密度が0.05個／μm2であり膜厚が15μｍの非磁性支持
体２上を用いた後は実施例１と同様にしてビデオテープ
を作製した。Comparative Example 3 After using the non-magnetic support 2 having a diameter of the protrusions of 0.10 μm, a height of 0.06 μm, a density of the protrusions of 0.05 / μm 2 and a film thickness of 15 μm in Comparative Example 3, it was performed. A video tape was produced in the same manner as in Example 1.
（比較例４） 実施例１のうち突起３の径が0.2μm,高さが0.10μｍで
突起密度が30個／μm2であり膜厚が15μｍの非磁性支持
体２上を用いた後は実施例１と同様にしてビデオテープ
を作製した。(Comparative Example 4) After using the non-magnetic support 2 having a diameter of the protrusions 3 of 0.2 μm, a height of 0.10 μm, a protrusion density of 30 / μm 2 and a film thickness of 15 μm, in Comparative Example 4, A video tape was produced in the same manner as in Example 1.
（比較例５） 実施例１のうち突起を全く設けない高平滑なままの表面
で膜厚が15μｍの非磁性支持体２上を用いた後は実施例
１と同様にしてビデオテープを作製した。(Comparative Example 5) A video tape was produced in the same manner as in Example 1 except that the non-magnetic support 2 having a thickness of 15 μm and having a highly smooth surface with no protrusions was used in Example 1. .
（比較例６） フィルム内部に無機質フィラーを添加することにより実
施例１と同程度の表面粗さを持つ膜厚が15μｍの非磁性
支持体２上を用いた後は実施例１と同様にしてビデオテ
ープを作製した。Comparative Example 6 The same procedure as in Example 1 was performed after using the non-magnetic support 2 having a film thickness of 15 μm and having the same surface roughness as in Example 1 by adding an inorganic filler inside the film. A video tape was made.
上記の各サンプルについて磁性層の摩擦係数とSN比を測
定した。The friction coefficient and SN ratio of the magnetic layer were measured for each of the above samples.
上記表において （１） 突起の直径、高さ、密度は走査電子顕微鏡で測
定し、裏面の突起の被覆率は（突起の半径×半径×円周
率×突起の密度）を百分率として得た。 In the above table, (1) The diameter, height, and density of the protrusions were measured with a scanning electron microscope, and the coverage of the protrusions on the back surface was obtained as (percentage of protrusions × radius × circumferential ratio × density of protrusions) as a percentage.
（２） 摩擦係数は、直径126mmのアルミ合金ドラムに
テープ磁性面が半周に渡って接触するようにし、ドラム
に対して入側張力を35g,テープ走行速度を3.3cm/秒に設
定したときの出力側の張力を測定し、次式から摩擦係数
を求めた。(2) The coefficient of friction was measured when the tape magnetic surface was in contact with an aluminum alloy drum with a diameter of 126 mm over a half circumference, and the entrance tension to the drum was set to 35 g and the tape running speed was set to 3.3 cm / sec. The tension on the output side was measured, and the friction coefficient was calculated from the following equation.
（３） SN比は、VHS方式VTR NV6200（松下電器（株）
製）を用い、50％ダーク信号の再生出力を925Cカラービ
デオノイズメータ（シバソク（株））に入力し1KHz−4M
Hzのフィルター時のSNを測定し比較例４を0dBとして相
対値を示した。 (3) SN ratio is VHS method VTR NV6200 (Matsushita Electric Co., Ltd.)
50% dark signal playback output to a 925C color video noise meter (Shibasoku Co., Ltd.)
The SN at the time of Hz filter was measured, and the relative value was shown by setting Comparative Example 4 to 0 dB.
以上のようにして得られた磁気テープは、上記表から明
らかなように、従来品に比べ走行性及び電磁変換特性に
優れたものである。As is clear from the above table, the magnetic tape obtained as described above is superior in running properties and electromagnetic conversion characteristics to the conventional products.
なお上記実施例では磁気テープについて説明したが、磁
気テープのみならず、磁気シート，磁気カード等の他の
磁気記録媒体に応用できることはいうまでもない。Although the magnetic tape has been described in the above embodiments, it is needless to say that it can be applied to other magnetic recording media such as a magnetic sheet and a magnetic card as well as the magnetic tape.
発明の効果 以上詳述したように、本発明によれば走行性及び電磁変
換特性に優れた磁気記録媒体が得られ、その実用上の価
値は大なるものがある。EFFECTS OF THE INVENTION As described above in detail, according to the present invention, a magnetic recording medium excellent in running property and electromagnetic conversion characteristics can be obtained, and its practical value is great.
図は本発明の実施例における磁気テープの断面構造を示
すものである。 １……磁性層、２……非磁性支持体、３……突起。The figure shows the cross-sectional structure of a magnetic tape according to an embodiment of the present invention. 1 ... Magnetic layer, 2 ... Non-magnetic support, 3 ... Protrusion.
Claims (1)
0.01〜0.10μｍ、突起の密度が１μm2当たり0.2〜20
個、支持体の被覆率が0.6〜４％である半球状の突起を
持つ非磁性支持体の反対面上に磁性層が設けられ、前記
非磁性支持体の突起の形状が磁性面上に転写されている
ことを特徴とする磁気記録媒体。1. The diameter of the protrusion on the surface is 0.05 to 0.20 μm, and the height is
0.01 to 0.10 μm, the density of protrusions is 0.2 to 20 per 1 μm 2.
A magnetic layer is provided on the opposite surface of the non-magnetic support having hemispherical projections having a coverage of 0.6 to 4%, and the shape of the projections of the non-magnetic support is transferred onto the magnetic surface. A magnetic recording medium characterized by being provided.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61027114A JPH0782632B2 (en) | 1986-02-10 | 1986-02-10 | Magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61027114A JPH0782632B2 (en) | 1986-02-10 | 1986-02-10 | Magnetic recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62184620A JPS62184620A (en) | 1987-08-13 |
| JPH0782632B2 true JPH0782632B2 (en) | 1995-09-06 |
Family
ID=12212039
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61027114A Expired - Lifetime JPH0782632B2 (en) | 1986-02-10 | 1986-02-10 | Magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0782632B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2811329B2 (en) * | 1989-09-14 | 1998-10-15 | コニカ株式会社 | Magnetic recording media |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52132807A (en) * | 1976-04-30 | 1977-11-07 | Tokyo Jiki Insatsu Kk | Magnetic recording media |
| JPS60111339A (en) * | 1983-11-21 | 1985-06-17 | Konishiroku Photo Ind Co Ltd | Magnetic recording medium and its manufacture |
-
1986
- 1986-02-10 JP JP61027114A patent/JPH0782632B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62184620A (en) | 1987-08-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |