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公开(公告)号：US20150380036A1
公开(公告)日：2015-12-31
申请号：US14753227
申请日：2015-06-29
Applicant: FUJIFILM Corporation
Inventor： Norihito KASADA , Masahito OYANAGI , Toshio TADA
Abstract: An aspect of the present invention relates to a magnetic tape comprising a magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, wherein ΔSFD in a longitudinal direction of the magnetic tape as calculated with Equation 1 ranges from 0.35 to 1.50: ΔSFD=SFD25° C.−SFD−190° C. Equation 1 wherein, in Equation 1, SFD25° C. denotes a switching field distribution SFD as measured in the longitudinal direction of the magnetic tape in an environment with a temperature of 25° C., and SFD−190° C. denotes a switching field distribution SFD as measured in the longitudinal direction of the magnetic tape in an environment with a temperature of −190° C.
Abstract translation: 本发明的一个方面涉及一种磁带，其包括在非磁性载体上包含铁磁性粉末和粘合剂的磁性层，其中沿式（1）计算的磁带的纵向方向上的SFD范围为0.35至1.50：＆Dgr; SFD = SFD25℃-FD-190℃等式1其中，在等式1中，SFD25℃表示在温度为25°的环境中在磁带的纵向上测量的开关场分布SFD C.和SFD-190℃表示在温度为-190℃的环境中在磁带的纵向测量的开关场分布SFD。
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公开(公告)号：US20150123026A1
公开(公告)日：2015-05-07
申请号：US14529544
申请日：2014-10-31
Applicant: DOWA ELECTRONICS MATERIALS CO., LTD. , FUJIFILM Corporation
Inventor： Kenji MASADA , Hirohisa OMOTO , Futoshi NAGASHIMA , Daisuke ABE , Toshio TADA , Norihito KASADA
IPC: H01F1/03
CPC classification number: H01F1/11 , C01G49/0036 , C01P2002/76 , C01P2006/42 , G11B5/70678
Abstract: Provided is magnetic powder capable of enhancing simultaneously both magnetic characteristics including SNP and durability of a magnetic recording medium. The hexagonal ferrite magnetic powder for a magnetic recording medium has a Ba/Fe molar ratio of 8.0% or more, a Bi/Fe molar ratio of 2.5% or more and an Al/Fe molar ratio of from 3.0 to 6.0%. The magnetic powder preferably has an activation volume Vact of from 1,400 to 1,800 nm3. The magnetic powder particularly preferably has a coercive force Hc of from 159 to 279 kA/m (which is approximately from 2,000 to 3,500 Oe) and a coercivity distribution SFD of from 0.3 to 1.0. The magnetic powder may contain, as an element that substitutes an Fe site of the hexagonal ferrite, at least one kind selected from divalent transition metals M1 and tetravalent transition metals M2.
Abstract translation: 提供了能够同时提高包括SNP的磁特性和磁记录介质的耐久性的磁粉。 用于磁记录介质的六方晶系铁氧体磁粉的Ba / Fe摩尔比为8.0％以上，Bi / Fe摩尔比为2.5％以上，Al / Fe摩尔比为3.0〜6.0％。 磁性粉末优选具有1400至1800nm 3的活化体积Vact。 磁性粉末特别优选具有159至279kA / m（约2,000至3,500Oe）的矫顽力Hc和0.3至1.0的矫顽力分布SFD。 作为代替六方晶系铁氧体的Fe部位的元素，可以含有选自二价过渡金属M1和四价过渡金属M2中的至少一种。
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公开(公告)号：US20230352224A1
公开(公告)日：2023-11-02
申请号：US18127707
申请日：2023-03-29
Applicant: DOWA ELECTRONICS MATERIALS CO., LTD. , FUJIFILM CORPORATION
Inventor： Akifumi ONODERA , Yasuto MIYAMOTO , Masaki KOSHIKO , Toshio TADA , Takashi FUJIMOTO
IPC: H01F1/34
CPC classification number: H01F1/348
Abstract: A magnetic powder for a magnetic recording medium includes magnetic particles in which Ba in hexagonal barium ferrite is partially substituted with Sr, wherein a Dx volume represented by Dx volume (nm3) = Dxc × π × (Dxa/2)2 is 2,200 nm3 or less, and an Sr/(Ba+Sr) molar ratio is 0.01 to 0.15. One that satisfies Ku ≥ 0.1 × [Sr/(Ba+Sr) molar ratio] + 0.13 is more preferred. For the formulas, Dxc is a crystallite diameter (nm) in a c-axis direction of a hexagonal ferrite crystal lattice, Dxa is a crystallite diameter (nm) in an a-axis direction of the same crystal lattice, π is a circular constant, and Ku is a magnetocrystalline anisotropy constant (MJ/m3). By providing the hexagonal ferrite magnetic powder formed of fine particles, an effect of improving the perpendicular squareness ratio SQ of a magnetic recording medium is large.
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公开(公告)号：US20190027175A1
公开(公告)日：2019-01-24
申请号：US16038771
申请日：2018-07-18
Applicant: FUJIFILM Corporation
Inventor： Takuto KUROKAWA , Norihito KASADA , Toshio TADA , Eiki OZAWA
Abstract: The magnetic tape includes a magnetic layer including ferromagnetic powder, non-magnetic powder, and a binding agent and a back coating layer including non-magnetic powder and a binding agent, in which the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, a center line average surface roughness measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm, an intensity ratio of a peak intensity of a diffraction peak of a (110) plane with respect to a peak intensity of a diffraction peak of a (114) plane of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical squareness ratio of the magnetic tape is 0.65 to 1.00, and a contact angle with respect to 1-bromonaphthalene measured regarding a surface of the back coating layer is 15.0° to 30.0°.
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公开(公告)号：US20170092315A1
公开(公告)日：2017-03-30
申请号：US15280195
申请日：2016-09-29
Applicant: FUJIFILM Corporation
Inventor： Eiki OZAWA , Norihito KASADA , Masahito OYANAGI , Toshio TADA
Abstract: The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on a nonmagnetic support, wherein 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, and the difference between the spacing Safter after vacuum heating the magnetic tape and the spacing Sbefore before vacuum heating the magnetic tape, Safter−Sbefore, is greater than 0 nm but less than or equal to 8.0 nm.
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Patent Agency Ranking
公开(公告)号：US20170004856A1
公开(公告)日：2017-01-05
申请号：US15197046
申请日：2016-06-29
Applicant: FUJIFILM Corporation
Inventor： Toshio TADA , Akinori SUGISHIMA , Tatsuya YAMASHITA , Norihito KASADA , Masahito OYANAGI
CPC classification number: G11B5/842 , G11B5/70678 , G11B5/714
Abstract: 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 nm3 to 2,400 nm3, and a ratio of the crystallite size Dx(107) obtained from a diffraction peak of a (107) plane to a particle size in a direction of an easy axis of magnetization DTEM as determined by observation with a transmission electron microscope, Dx(107)/DTEM, is greater than or equal to 1.1.
Abstract translation: 磁记录介质具有在非磁性载体上含有铁磁性粉末和粘合剂的磁性层，其中铁磁性粉末为铁磁性六角铁氧体粉末，铁磁性六方晶系铁氧体粉末的X射线衍射分析的微晶体积为1000nm 3 至（2,400nm 3），通过透射电子显微镜观察确定由（107）面的衍射峰获得的微晶尺寸Dx（107）与易磁化轴DTEM方向上的粒径的比例， Dx（107）/ DTEM，大于或等于1.1。
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公开(公告)号：US20160189740A1
公开(公告)日：2016-06-30
申请号：US14978834
申请日：2015-12-22
Applicant: FUJIFILM Corporation
Inventor： Masahito OYANAGI , Norihito KASADA , Toshio TADA , Kazuyuki KITADA
CPC classification number: G11B5/71 , G11B5/70 , G11B5/7305 , G11B5/78 , G11B5/8404 , G11B5/842
Abstract: 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/m2, 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 %.
Abstract translation: 提供了一种磁带，其在非磁性载体上包括非磁性粉末和粘合剂的非磁性层，并且在非磁性层上包括含铁磁粉末和粘合剂的磁性层; 其中至少所述磁性层包含一种或多种选自脂肪酸和脂肪酸酰胺的组分; 在从磁带的磁性层一侧的表面提取的成分中，选自由磁带的每单位面积的脂肪酸和脂肪酸酰胺组成的组中的成分的量少于或等于15.0mg / m 2，通过在磁带的磁性层一侧的表面上以10度的光电子起飞角度进行的通过X射线光电子能谱得到的碳浓度C大于或等于50 原子％。
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公开(公告)号：US20190027179A1
公开(公告)日：2019-01-24
申请号：US16037681
申请日：2018-07-17
Applicant: FUJIFILM Corporation
Inventor： Eiki OZAWA , Norihito KASADA , Toshio TADA , Takuto KUROKAWA
Abstract: The magnetic recording medium includes a magnetic layer which contains ferromagnetic hexagonal ferrite powder and a binder, in which the magnetic layer contains an abrasive and a fatty acid ester, Int (110)/Int (114) of a crystal structure of the hexagonal ferrite, determined by performing XRD analysis on the magnetic layer by using an In-Plane method, is equal to or higher than 0.5 and equal to or lower than 4.0, a squareness ratio of the magnetic recording medium in a vertical direction is equal to or higher than 0.65 and equal to or lower than 1.00, FWHMbefore and FWHMafter is greater than 0 nm and equal to or smaller than 7.0 nm, and a difference between spacings measured within a surface of the magnetic layer by an optical interference method before and after the heating in a vacuum is greater than 0 nm and equal to or smaller than 8.0 nm.
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公开(公告)号：US20190027174A1
公开(公告)日：2019-01-24
申请号：US16037596
申请日：2018-07-17
Applicant: FUJIFILM Corporation
Inventor： Toshio TADA , Norihito KASADA , Eiki OZAWA , Takuto KUROKAWA
Abstract: Provided is a magnetic tape in which an Ra measured regarding a surface of a magnetic layer is equal to or smaller than 1.8 nm, Int(110)/Int(114) of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical squareness ratio of the magnetic tape is 0.65 to 1.00, the back coating layer includes one or more kinds of component selected from the group consisting of fatty acid and fatty acid amide, and a C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the back coating layer at a photoelectron take-off angle of 10 degrees is equal to or greater than 35 atom %.
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公开(公告)号：US20190027168A1
公开(公告)日：2019-01-24
申请号：US16038687
申请日：2018-07-18
Applicant: FUJIFILM Corporation
Inventor： Norihito KASADA , Toshio TADA , Eiki OZAWA , Takuto KUROKAWA
Abstract: The magnetic recording medium includes a non-magnetic support and a magnetic layer which contains ferromagnetic powder and a binder, in which the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, the magnetic layer contains an abrasive, Int (110)/Int (114) 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 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, a squareness ratio of the magnetic recording medium in a vertical direction is equal to or higher than 0.65 and equal to or lower than 1.00, and a logarithmic decrement obtained by performing a pendulum viscoelasticity test on a surface of the magnetic layer is equal to or lower than 0.050.
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