JP2020184400A5

JP2020184400A5 -

Info

Publication number: JP2020184400A5
Application number: JP2020104582A
Authority: JP
Filing date: 2020-06-17
Publication date: 2021-05-06
Anticipated expiration: 2039-04-26

Description

本技術は、磁性層、非磁性層、ベース層およびバック層をこの順に含む層構造を有する磁気記録媒体であって、
前記磁気記録媒体の平均厚みｔ_Ｔが、３．５μｍ≦ｔ_Ｔ≦５．５μｍであり、
前記磁性層には前記磁気記録媒体の長手方向に延びる複数のサーボバンドが設けられており、
前記サーボバンドには、複数のハの字状のサーボパターンが記録されており、
前記磁性層は磁性粉と第一の結着剤を含み、
前記ベース層はポリエステル系樹脂を含み、
前記非磁性層は非磁性粉と第二の結着剤を含み、
前記磁気記録媒体を１／２インチ幅かつ２５０ｍｍの長さに切り出したサンプルに対して、温度２５℃相対湿度５０％の環境下において、前記サンプルの長手方向に０．２Ｎ、０．６Ｎ、及び１．０Ｎの荷重をこの順にかけ、０．２Ｎ及び１．０Ｎの荷重がかけられた場合において測定された前記サンプルの幅を用いて、以下の式より求めた、前記磁気記録媒体の長手方向のテンション変化に対する前記磁気記録媒体の幅方向の寸法変化量Δｗが、７００［ｐｐｍ／Ｎ］≦Δｗであり、

（但し、式中、Ｄ（０．２Ｎ）及びＤ（１．０Ｎ）はそれぞれ、前記サンプルの長手方向に０．２Ｎ及び１．０Ｎの荷重をかけたときの前記サンプルの幅を示す。）
前記サーボパターンが再生されたサーボ信号から得られるＰＥＳ（ＰｏｓｉｔｉｏｎＥｒｒｏｒＳｉｇｎａｌ）値の標準偏差σＰＥＳが、σＰＥＳ≦２５ｎｍであり、
前記磁性層側の表面とＬＴＯ３ヘッドとの間の摩擦係数μ_１の測定を２５０回行った場合の前記摩擦係数μ_１の最大値μ_１Ｍが、０．０４≦μ_１Ｍ≦０．５である、
磁気記録媒体を提供する。
前記磁気記録媒体は、垂直方向における角形比が６５％以上でありうる。
前記寸法変化量Δｗは、７０７［ｐｐｍ／Ｎ］≦Δｗ≦２０００［ｐｐｍ／Ｎ］でありうる。
前記寸法変化量Δｗは、７５０［ｐｐｍ／Ｎ］≦Δｗ≦２０００［ｐｐｍ／Ｎ］でありうる。
前記寸法変化量Δｗは、７０７［ｐｐｍ／Ｎ］≦Δｗ≦８００［ｐｐｍ／Ｎ］でありうる。
前記バック層の表面粗度Ｒ_ａｂは、３．０ｎｍ≦Ｒ_ａｂ≦７．５ｎｍでありうる。
前記磁性層側の表面と前記バック層側の表面との間の摩擦係数μが、０．２０≦μ≦０．８０でありうる。
前記磁気記録媒体の温度膨張係数αは、５．５［ｐｐｍ／℃］≦α≦９［ｐｐｍ／℃］であり、且つ、前記磁気記録媒体の湿度膨張係数βが、β≦５．５［ｐｐｍ／％ＲＨ］でありうる。
前記磁気記録媒体のポアソン比ρは、０．２５≦ρでありうる。
前記磁気記録媒体の長手方向の弾性限界値σ_ＭＤが、０．７［Ｎ］≦σ_ＭＤでありうる。
前記弾性限界値σ_ＭＤは、弾性限界測定を行う際の速度Ｖに依らないものでありうる。
前記磁性層が垂直配向しているものであってよい。
前記バック層の平均厚みｔ_ｂが、ｔ_ｂ≦０．６μｍでありうる。
前記磁性層の平均厚みｔ_ｍが、３５ｎｍ≦ｔ_ｍ≦１２０ｎｍでありうる。
前記磁性粉は、ε酸化鉄磁性粉、バリウムフェライト磁性粉、コバルトフェライト磁性粉、又はストロンチウムフェライト磁性粉を含みうる。
前記標準偏差σＰＥＳは、１７ｎｍ≦σＰＥＳ≦２３ｎｍでありうる。
垂直方向における角形比は、７３％以上でありうる。
前記磁性粉は、バリウムフェライト磁性粉を含み、
前記磁性層の平均厚みｔ _ｍが、３５ｎｍ≦ｔ _ｍ ≦１００ｎｍであり、
前記磁気記録媒体の垂直方向における保磁力Ｈｃが、１６０ｋＡ／ｍ以上２８０ｋＡ／ｍ以下でありうる。
前記第一の結着剤は、ポリウレタン系樹脂または塩化ビニル系樹脂を含みうる。
前記第二の結着剤は、ポリウレタン系樹脂または塩化ビニル系樹脂を含みうる。
前記磁気記録媒体の幅は、１１ｍｍ以上１９ｍｍ以下でありうる。
本技術は、
前記磁気記録媒体と、
カートリッジケースと、
リールを含み、
前記磁気記録媒体が、前記リールに巻き取られた状態で前記カートリッジケース内に収容されている磁気記録カートリッジも提供する。 This technology, the magnetic layer, nonmagnetic layer, a magnetic recording medium to have a layered structure including a base layer and a back layer in this order,
The average thickness t _T of the magnetic recording medium is 3.5 μm ≦ t _T ≦ 5. It is 5 μm and
The magnetic layer is provided with a plurality of servo bands extending in the longitudinal direction of the magnetic recording medium.
A plurality of C-shaped servo patterns are recorded in the servo band.
The magnetic layer contains a magnetic powder and a first binder and contains
The base layer contains a polyester resin and contains
The non-magnetic layer contains a non-magnetic powder and a second binder and contains.
0.2N, 0.6N, and 0.2N, 0.6N in the longitudinal direction of the sample in an environment of a temperature of 25 ° C. and a relative humidity of 50% with respect to a sample obtained by cutting the magnetic recording medium into a 1/2 inch width and a length of 250 mm. A load of 1.0 N was applied in this order, and the width of the sample measured when a load of 0.2 N and 1.0 N was applied was used to obtain the longitudinal direction of the magnetic recording medium obtained from the following equation. The amount of dimensional change Δw in the width direction of the magnetic recording medium with respect to the change in tension is 700 [ppm / N] ≦ Δw.

(However, in the formula, D (0.2N) and D (1.0N) indicate the width of the sample when a load of 0.2N and 1.0N is applied in the longitudinal direction of the sample, respectively.)
The standard deviation σPES of the PES (Position Error Signal) value obtained from the servo signal in which the servo pattern is reproduced is σPES ≦ 25 nm.
The maximum value μ _1M of the friction coefficient μ ₁ _{when the friction coefficient μ 1} between the surface on the magnetic layer side and the LTO3 head is measured 250 times is 0.04 ≦ μ _1M ≦ 0.5. ,
Provide a magnetic recording medium.
The magnetic recording medium can have a square ratio of 65% or more in the vertical direction.
The amount of dimensional change Δw can be 707 [ ppm / N ] ≦ Δw ≦ 2000 [ppm / N] .
The amount of dimensional change Δw can be 750 [ ppm / N ] ≤Δw ≤2000 [ppm / N] .
The amount of dimensional change Δw can be 707 [ ppm / N ] ≦ Δw ≦ 800 [ppm / N] .
Surface roughness _{R ab} before Symbol back layer may be 3.0nm ≦ _{R ab} ≦ 7.5nm.
Friction coefficient between the front Symbol magnetic layer-side surface and the back layer side of the surface mu is can be a 0.20 ≦ μ ≦ 0.80.
The coefficient of thermal expansion α of the magnetic recording medium is 5.5 [ ppm / ° C ] ≦ α ≦ 9 [ ppm / ° C ] , and the coefficient of thermal expansion β of the magnetic recording medium is β ≦ 5.5 [. ppm /% RH ] .
The Poisson's ratio ρ of the magnetic recording medium can be 0.25 ≦ ρ.
_{The elastic limit value σ MD in} the longitudinal direction of the magnetic recording medium can be 0.7 [ N ] ≤ σ _MD.
The elastic limit value σ _MD may not depend on the velocity V when performing the elastic limit measurement.
It may be those before Symbol magnetic layer is oriented vertically.
The average thickness _{t b} before Symbol back layer may be a _{t b} ≦ 0.6 .mu.m.
The average thickness _{t m} prior Symbol magnetic layer may be a _{35 nm ≦ t m ≦ 120 nm} .
Before Symbol magnetic powder, epsilon iron oxide magnetic powder, a barium ferrite magnetic powders may include cobalt ferrite magnetic powder, or strontium ferrite magnetic powder.
The standard deviation σPES can be 17 nm ≦ σ PES ≦ 23 nm.
The square ratio in the vertical direction can be 73% or more.
The magnetic powder contains barium ferrite magnetic powder and contains
The average thickness _{t m} of the magnetic layer is a 35nm ≦ _{t m} ≦ 100nm,
The coercive force Hc in the vertical direction of the magnetic recording medium can be 160 kA / m or more and 280 kA / m or less.
The first binder may include a polyurethane-based resin or a vinyl chloride-based resin.
The second binder may include a polyurethane-based resin or a vinyl chloride-based resin.
The width of the magnetic recording medium can be 11 mm or more and 19 mm or less.
This technology
With the magnetic recording medium
Cartridge case and
Including reel
Also provided is a magnetic recording cartridge in which the magnetic recording medium is housed in the cartridge case while being wound on the reel.

Claims

Magnetic layer, nonmagnetic layer, a base layer and a back layer to a magnetic recording medium to have a layer structure comprising in this order,
The average thickness t _T of the magnetic recording medium is 3.5 μm ≦ t _T ≦ 5. It is 5 μm and
The magnetic layer is provided with a plurality of servo bands extending in the longitudinal direction of the magnetic recording medium.
A plurality of C-shaped servo patterns are recorded in the servo band.
The magnetic layer contains a magnetic powder and a first binder and contains
The base layer contains a polyester resin and contains
The non-magnetic layer contains a non-magnetic powder and a second binder and contains.
0.2N, 0.6N, and 0.2N, 0.6N in the longitudinal direction of the sample in an environment of a temperature of 25 ° C. and a relative humidity of 50% with respect to a sample obtained by cutting the magnetic recording medium into a 1/2 inch width and a length of 250 mm. A load of 1.0 N was applied in this order, and the width of the sample measured when a load of 0.2 N and 1.0 N was applied was used to obtain the longitudinal direction of the magnetic recording medium obtained from the following equation. The amount of dimensional change Δw in the width direction of the magnetic recording medium with respect to the change in tension is 707 [ppm / N] ≦ Δw.

(However, in the formula, D (0.2N) and D (1.0N) indicate the width of the sample when a load of 0.2N and 1.0N is applied in the longitudinal direction of the sample, respectively.)
The standard deviation σPES of the PES (Position Error Signal) value obtained from the servo signal in which the servo pattern is reproduced is σPES ≦ 25 nm.
The maximum value μ _1M of the friction coefficient μ ₁ _{when the friction coefficient μ 1} between the surface on the magnetic layer side and the LTO3 head is measured 250 times is 0.04 ≦ μ _1M ≦ 0.5. ,
Magnetic recording medium.

The magnetic recording medium according to claim 1, wherein the square ratio in the vertical direction is 65% or more.

The magnetic recording medium according to claim 1 or 2 , wherein the amount of dimensional change Δw is 707 [ ppm / N ] ≤Δw ≤2000 [ppm / N].

The magnetic recording medium according to any one of claims 1 to 3, wherein the amount of dimensional change Δw is 750 [ ppm / N ] ≤Δw ≤2000 [ppm / N].

The magnetic recording medium according to any one of claims 1 to 3, wherein the amount of dimensional change Δw is 707 [ ppm / N ] ≤Δw ≤800 [ppm / N].

Surface roughness _{R ab} before Symbol back layer is 3.0nm ≦ _{R ab} ≦ 7.5nm, magnetic recording medium according to any one of claims 1 to 5.

Friction coefficient between the front Symbol magnetic layer-side surface and the back layer side of the surface mu is a 0.20 ≦ μ ≦ 0.80, the magnetic recording according to any one of claims 1 to 6 Medium.

The coefficient of thermal expansion α is 5.5 [ ppm / ° C ] ≤ α ≤ 9 [ ppm / ° C ] , and
Humidity expansion coefficient β is β ≦ 5.5 [ ppm /% RH ] .
The magnetic recording medium according to any one of claims 1 to 7.

The magnetic recording medium according to any one of claims 1 to 8, wherein the Poisson's ratio ρ is 0.25 ≦ ρ.

The magnetic recording medium according to any one of claims 1 to 9, wherein the elastic limit value σ _{MD in the} longitudinal direction is 0.7 [ N ] ≤ σ _MD.

The magnetic recording medium according to claim 10, wherein the elastic limit value σ _MD does not depend on the velocity V when performing the elastic limit measurement.

The magnetic recording medium according to any one of claims 1 to 11, wherein the magnetic layer is vertically oriented.

The average thickness _{t b} before Symbol back layer, a _{t b} ≦ 0.6 .mu.m, a magnetic recording medium according to any one of claims 1 to 12.

The average thickness _{t m} of the magnetic layer, a 35nm ≦ _{t m} ≦ 120nm, magnetic recording medium according to any one of claims 1 to 13.

The magnetic recording medium according to any one of claims 1 to 14, wherein the magnetic powder contains ε-iron oxide magnetic powder, barium ferrite magnetic powder, cobalt ferrite magnetic powder, or strontium ferrite magnetic powder.

The magnetic recording medium according to any one of claims 1 to 15, wherein the standard deviation σPES is 17 nm ≦ σPES ≦ 23 nm.

The magnetic recording medium according to any one of claims 1 to 16, wherein the square ratio in the vertical direction is 73% or more.

The magnetic powder contains barium ferrite magnetic powder and contains
Average thickness t of the magnetic layer _ｍm However, 35 nm ≤ t _ｍm ≤100 nm
The magnetic recording medium according to any one of claims 1 to 17, wherein the coercive force Hc in the vertical direction of the magnetic recording medium is 160 kA / m or more and 280 kA / m or less.

The magnetic recording medium according to any one of claims 1 to 18, wherein the first binder contains a polyurethane resin or a vinyl chloride resin.

The magnetic recording medium according to any one of claims 1 to 19, wherein the second binder contains a polyurethane resin or a vinyl chloride resin.

The magnetic recording medium according to any one of claims 1 to 20, wherein the width of the magnetic recording medium is 11 mm or more and 19 mm or less.

The magnetic recording medium according to any one of claims 1 to 21 and the magnetic recording medium.
Cartridge case and
Including reel
A magnetic recording cartridge in which the magnetic recording medium is housed in the cartridge case in a state of being wound on the reel.