Fujifilm Corporation

Masahito Oyanagi

Norihito Kasada

Toshio Tada

Eiki Ozawa

Takuto Kurokawa

Takuro Sugiyama

Akinori Sugishima

Kazuyuki Kitada

Takeshi Harasawa

Kengo Saito

Yasuhiro Kawatani

Tatsuya Yamashita

The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on one surface of a nonmagnetic support and has a backcoat layer containing nonmagnetic powder and binder on the other surface thereof, wherein the thickness of the backcoat layer is less than or equal to 0.20 &#x3bc;m, the contact angle for 1-bromonaphthalene that is measured on the surface of the backcoat layer falls within a range of 10.0&#xb0; to 30.0&#xb0;, and the contact angle for 1-bromonaphthalene that is measured on the surface of the magnetic layer falls within a range of 45.0&#xb0; to 55.0&#xb0;.

Magnetic tape

The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on a nonmagnetic support, wherein the centerline average surface roughness Ra as measured on the surface on the magnetic layer side of the magnetic tape is less than or equal to 1.8 nm, and the logarithmic decrement as determined by a pendulum viscoelasticity test on the surface on the magnetic layer side of the magnetic tape is less than or equal to 0.050.

Magnetic tape having a characterized magnetic layer and method of manufacturing the same

The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on one surface of a nonmagnetic support and has a backcoat layer containing nonmagnetic powder and binder on the other surface thereof, wherein the thickness of the backcoat layer is less than or equal to 0.20 &#x3bc;m, and the contact angle for 1-bromonaphthalene that is measured on the surface of the backcoat layer falls within a range of 10.0&#xb0; to 30.0&#xb0;.

The magnetic tape has a magnetic layer containing ferromagnetic powder, abrasive, and binder on a nonmagnetic support, wherein the centerline average surface roughness Ra measured on the surface of the magnetic layer is less than or equal to 1.8 nm, the contact angle for 1-bromonaphthalene that is measured on the surface of the magnetic layer falls within a range of 45.0&#xb0; to 60.0&#xb0;, and the coefficient of friction that is measured on the base portion of the surface of the magnetic layer is less than or equal to 0.35.

The magnetic recording medium has a non-magnetic support and a magnetic layer which is provided on the support and contains ferromagnetic powder and a binder, in which the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, the magnetic layer contains an abrasive, an intensity ratio (Int (110)/Int (114)) of a peak intensity Int (110) of a diffraction peak of (110) plane of a crystal structure of the hexagonal ferrite, determined by performing X-ray diffraction analysis on the magnetic layer by using an In-Plane method, to a peak intensity Int (114) of a diffraction peak of (114) plane of the crystal structure is equal to or higher than 0.5 and equal to or lower than 4.0, and a squareness ratio in a vertical direction is equal to or higher than 0.65 and equal to or lower than 1.00. The present invention also provides a method for manufacturing the magnetic recording medium.

Magnetic recording medium having characterized magnetic layer and method for manufacturing same

The magnetic tape has a nonmagnetic layer containing nonmagnetic powder and binder on a nonmagnetic support and a magnetic layer containing ferromagnetic powder and binder on the nonmagnetic layer, wherein a fatty acid ester is contained in at least the magnetic layer, the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, the ferromagnetic hexagonal ferrite powder has a crystallite volume as determined by X-ray diffraction analysis ranges from 1,000 nmto 2,400 nm, and a ratio of the crystallite size Dobtained from a diffraction peak of a (107) plane to a particle size in a direction of an easy axis of magnetization Das determined by observation with a transmission electron microscope, D/D, is greater than or equal to 1.1, and &#x394;SFD in a longitudinal direction of the magnetic tape as calculated with Equation 1: &#x394;SFD=SFD&#x2212;SFD, ranges from 0.50 to 1.60.

Magnetic tape and method of manufacturing the same

A magnetic tape has a magnetic layer containing ferromagnetic powder and binder on a nonmagnetic support. The magnetic layer contains a fatty acid ester. The full width at half maximum of the spacing distribution as measured by optical interferometry on the magnetic layer side surface of the magnetic tape before vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 5.0 nm. The full width at half maximum of the spacing distribution after vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 5.0 nm. The difference between the spacing Safter vacuum heating the magnetic tape and the spacing Sbefore vacuum heating the magnetic tape, S&#x2212;S, is greater than 0 nm but less than or equal to 8.0 nm.

Magnetic tape having characterized magnetic layer and magnetic tape device

A magnetic tape is provided in which the center line average surface roughness Ra measured regarding the surface of the magnetic layer is less than or equal to 1.8 nm, and the logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is less than or equal to 0.050. A back coating layer includes one or more components selected from a fatty acid and a fatty acid amide. In addition, the C&#x2014;H derived C concentration calculated from the C&#x2014;H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed regarding the surface of the back coating layer at a photoelectron take-off angle of 10 degrees is greater than or equal to 35 atom %.

Magnetic tape having controlled surface properties of the back coating layer and magnetic layer

The magnetic tape has a magnetic layer and a backcoat layer. The Ra on the magnetic layer side surface is less than or equal to 1.8 nm, the coefficient of friction measured on the base portion of the magnetic layer side surface is less than or equal to 0.35, and the Ra measured on the backcoat layer side surface is less than or equal to 5.0 nm. The backcoat layer contains a fatty acid ester. In addition, the FWHMmeasured on the backcoat layer side surface before vacuum heating is greater than 0 nm but less than or equal to 10.0 nm, the FWHMafter vacuum heating is greater than 0 nm but less than or equal to 10.0 nm, and the difference between the spacing measured on the backcoat layer side surface after and before vacuum heating is greater than 0 nm but less than or equal to 8.0 nm.

Magnetic tape having characterized backcoat layer and method of manufacturing the same

A magnetic tape has a magnetic layer and a backcoat layer. Each of the magnetic layer and the backcoat layer contains a fatty acid ester. The Ra measured on the magnetic layer side surface is less than or equal to 2.8 nm. The difference between the spacing measured by optical interferometry on the magnetic layer side surface after and before vacuum heating is greater than 0 nm but less than or equal to 8.0 nm. The FWHMon the backcoat layer side surface is greater than 0 nm but less than or equal to 10.0 nm. The FWHMon the backcoat layer side surface is greater than 0 nm but less than or equal to 10.0 nm. The difference between the spacing measured on the backcoat layer side surface after and before vacuum heating is greater than 0 nm but less than or equal to 8.0 nm.

The magnetic tape comprises, on a nonmagnetic support, a nonmagnetic layer comprising nonmagnetic powder and binder, and on the nonmagnetic layer, a magnetic layer comprising ferromagnetic powder, nonmagnetic powder, and binder, wherein a total thickness of the magnetic tape is less than or equal to 4.80 &#x3bc;m, and a coefficient of friction as measured on a base portion of a surface of the magnetic layer is less than or equal to 0.35.

The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on the surface on one side of a nonmagnetic support and has a backcoat layer containing nonmagnetic powder and binder on the surface on the other side of the nonmagnetic support, wherein the backcoat layer is less than or equal to 0.30 &#x3bc;m in thickness; and the logarithmic decrement as determined by a pendulum viscoelasticity test on the surface on the backcoat layer side of the magnetic tape is less than or equal to 0.060.

Magnetic tape having controlled surface properties of the backcoat layer and method of manufacturing the same

Magnetic tape having controlled surface properties of the magnetic layer and method of manufacturing the same

The magnetic recording medium has a magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, wherein the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, and the ferromagnetic hexagonal ferrite powder has a crystallite volume as determined by X-ray diffraction analysis ranges from 1,000 nmto 2,400 nm, and a ratio of the crystallite size Dobtained from a diffraction peak of a (107) plane to a particle size in a direction of an easy axis of magnetization Das determined by observation with a transmission electron microscope, D/D, is greater than or equal to 1.1.

Magnetic recording medium and method of manufacturing the same

Provided is a magnetic tape, which comprises, on a nonmagnetic support, a nonmagnetic layer comprising nonmagnetic powder and binder, and on the nonmagnetic layer, a magnetic layer comprising ferromagnetic powder and binder; wherein at least the magnetic layer comprises one or more components selected from the group consisting of a fatty acid and a fatty acid amide; a quantity of components selected from the group consisting of a fatty acid and a fatty acid amide per unit area of the magnetic tape among components that are extracted from a surface on the magnetic layer side of the magnetic tape is less than or equal to 15.0 mg/m, and a concentration of carbon, C, that is obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on the surface on the magnetic layer side of the magnetic tape is greater than or equal to 50 atom %.

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Minami-ashigara, Japan

Masahito Oyanagi