Nonmagnetic Particles In Underlayer (e.g., A12o3 Particles, Etc.) Patents (Class 428/840.2)
  • Patent number: 11270729
    Abstract: A tape-shaped magnetic recording medium includes a base, a nonmagnetic layer that is provided on the base and contains a nonmagnetic powder, and a magnetic layer that is provided on the nonmagnetic layer and contains a magnetic powder. In the magnetic recording medium, the magnetic layer has an average thickness of not more than 90 nm, the magnetic powder has an average aspect ratio of from 1.0 to 3.0, a coercive force Hc1 in a perpendicular direction is not more than 3,000 Oe, the coercive force Hc1 in the perpendicular direction and a coercive force Hc2 in a longitudinal direction satisfy the relation of Hc2/Hc1?0.8, the nonmagnetic layer has an average thickness of not more than 1.1 ?m, and the nonmagnetic powder has an average particle volume of not more than 2.0×10?5 ?m3.
    Type: Grant
    Filed: April 1, 2019
    Date of Patent: March 8, 2022
    Assignee: Sony Corporation
    Inventors: Masaru Terakawa, Minoru Yamaga, Katsunori Maeshima
  • Patent number: 10026430
    Abstract: 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 ?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.
    Type: Grant
    Filed: September 28, 2015
    Date of Patent: July 17, 2018
    Assignee: FUJIFILM Corporation
    Inventors: Norihito Kasada, Masahito Oyanagi, Toshio Tada, Yasuhiro Kawatani
  • Patent number: 9959894
    Abstract: The magnetic tape comprises a nonmagnetic layer comprising nonmagnetic powder and binder on a nonmagnetic support, and comprises a magnetic layer comprising ferromagnetic powder and binder on the nonmagnetic layer, wherein a fatty acid ester, a fatty acid amide, and a fatty acid are contained in either one or both of the magnetic layer and the nonmagnetic layer, with the magnetic layer and nonmagnetic layer each comprising at least one selected from the group consisting of a fatty acid ester, a fatty acid amide, and a fatty acid, a quantity of fatty acid ester per unit area of the magnetic layer in extraction components extracted from a surface of the magnetic layer with n-hexane falls within a range of 1.00 mg/m2 to 10.
    Type: Grant
    Filed: September 30, 2015
    Date of Patent: May 1, 2018
    Assignee: FUJIFILM Corporation
    Inventor: Kazufumi Omura
  • Patent number: 9875766
    Abstract: The magnetic tape has a nonmagnetic layer, a magnetic layer, and a backcoat layer; with one or both of the magnetic layer and nonmagnetic layer comprising at least one type of lubricant; with the backcoat layer comprising at least one type of lubricant; with a surface lubricant index as measured on a surface of the magnetic layer ranging from 1.00 to 4.00; and with a state of a presence of indentations on the surface of the magnetic layer satisfying condition 1 and condition 2: condition 1: a number of indentations greater than or equal to 5 nm and less than 10 nm in depth of 5 to 1,000 per 350 ?m×260 ?m area; and condition 2: a number of indentations greater than or equal to 10 nm in depth of less than or equal to 100 per 350 ?m×260 ?m area.
    Type: Grant
    Filed: April 28, 2016
    Date of Patent: January 23, 2018
    Assignee: FUJIFILM Corporation
    Inventor: Masahiko Mori
  • Publication number: 20130260179
    Abstract: An aspect of the present invention relates to a magnetic recording medium, which comprises a nonmagnetic layer containing a nonmagnetic powder and a binder and a magnetic layer containing a ferromagnetic powder and a binder in this order on a nonmagnetic support, wherein the nonmagnetic layer has a thickness of equal to or less than 300 nm; a composite elastic modulus as measured on a surface of the magnetic layer ranges from 6.0 to 8.0 GPa; the magnetic layer comprises an abrasive with a specific surface area by BET method ranging from 14 m2/g to 40 m2/g; and a surface abrasive occupancy on a surface of the magnetic layer ranges from 0.2% to 2%.
    Type: Application
    Filed: March 15, 2013
    Publication date: October 3, 2013
    Applicant: FUJIFILM CORPORATION
    Inventors: Norihito KASADA, Masahide SATO, Isamu WATANABE
  • Publication number: 20120177950
    Abstract: An aspect of the present invention relates to a binder resin composition for a magnetic recording medium, which comprises a vinyl chloride resin containing a radiation-curable functional group, and a methacrylate compound denoted by formula (A): in an amount of equal to or more than 0.3 weight percent but equal to or less than 10 weight percent relative to a content of the vinyl chloride resin.
    Type: Application
    Filed: January 11, 2012
    Publication date: July 12, 2012
    Applicant: FUJIFILM CORPORATION
    Inventor: Kazufumi OMURA
  • Publication number: 20120045664
    Abstract: A magnetic recording medium of the present invention is a magnetic recording medium including a non-magnetic substrate; a non-magnetic layer that is formed on one of principal surfaces of the non-magnetic substrate and contains a non-magnetic powder, a binder, and a lubricant; and a magnetic layer that is formed on a principal surface of the non-magnetic layer opposite to the non-magnetic substrate and contains a magnetic powder and a binder. The magnetic powder has an average particle size between 10 inn and 35 nm inclusive. The lubricant is migratable to the magnetic layer and forms a lubricant layer on a surface of the magnetic layer when a pressure is applied to the magnetic layer. When spacing of the surface of the magnetic layer before and after washing the lubricant with n-hexane is measured with a TSA (Tape Spacing Analyzer), the value of the spacing after washing is 3 to 10 nm, and the value of the spacing before washing is 1 to 5 nm smaller than the value of the spacing after washing.
    Type: Application
    Filed: August 16, 2011
    Publication date: February 23, 2012
    Inventors: Kenji TANAKA, Masao Fujita, Sadamu Kuse
  • Publication number: 20110229740
    Abstract: An aspect of the present invention relates to a magnetic tape comprising a nonmagnetic layer containing a nonmagnetic powder and a binder and a magnetic layer containing a ferromagnetic powder and a binder in this order on a nonmagnetic support. The nonmagnetic layer is a radiation-cured layer formed by curing with radiation a given radiation-curable composition. The nonmagnetic layer has a thickness ranging from 0.5 to 1.3 ?m. The relation between the nonmagnetic powder and the binder component contained in the radiation-curable composition satisfies equation (I): 480?(BET specific surface area of the nonmagnetic powder (m2/g)×weight of the nonmagnetic powder (g))/weight of the binder component (g)?650??(I).
    Type: Application
    Filed: March 15, 2011
    Publication date: September 22, 2011
    Applicant: FUJIFILM CORPORATION
    Inventors: Shinji TSUJIMOTO, Katsumi ARAKI, Tomohiro ICHIKAWA
  • Publication number: 20100273029
    Abstract: An aspect of the present invention relates to a mixture of a sulfonate group-containing compound denoted by general formula (1) with a protonic acid: wherein, in general formula (1), X denotes a divalent linking group; each of R1 and R2 independently denotes an alkyl group comprising at least one hydroxyl group and equal to or more than three carbon atoms or an aralkyl group comprising at least one hydroxyl group and equal to or more than eight carbon atoms; and M denotes a cation.
    Type: Application
    Filed: April 27, 2010
    Publication date: October 28, 2010
    Applicant: FUJIFILM CORPORATION
    Inventors: Kazufumi OMURA, Katsumi ARAKI
  • Patent number: 7754355
    Abstract: A magnetic recording medium is provided that includes a non-magnetic support, a radiation-cured layer cured by exposing a layer containing a radiation curing compound to radiation, and a magnetic layer comprising a ferromagnetic powder dispersed in a binder. The radiation-cured layer and the magnetic layer are provided in that order above the non-magnetic support. The radiation curing compound has a C2 to C18 alkyl group, a C6 to C10 cyclic structure, and two or more radiation curing functional groups per molecule.
    Type: Grant
    Filed: April 20, 2005
    Date of Patent: July 13, 2010
    Assignee: FUJIFILM Corporation
    Inventors: Yuichiro Murayama, Hiroshi Hashimoto
  • Publication number: 20100055504
    Abstract: An aspect of the present invention relates to a method of modifying a surface of a powder, comprising mixing a powder with a compound denoted by general formula (I): wherein, in general formula (I), each of R10 and R13 independently denotes a hydrogen atom, alkyl group, or aryl group, each of R11 and R12 independently denotes an alkyl group or an aryl group, and L denotes a single bond or an oxygen atom.
    Type: Application
    Filed: August 26, 2009
    Publication date: March 4, 2010
    Applicant: FUJIFILM Corporation
    Inventor: Kazufumi OMURA
  • Publication number: 20100055505
    Abstract: An aspect of the present invention relates to a magnetic recording medium comprising a magnetic layer comprising a ferromagnetic power and a binder on a nonmagnetic support, wherein, the binder comprises a constituent component in the form of a polyurethane resin obtained from starting materials in the form of a polyisocyanate and a polyol denoted by general formula (I): wherein, in general formula (I), Z1 denotes an atom group forming a lactone ring with two adjacent carbon atoms.
    Type: Application
    Filed: August 27, 2009
    Publication date: March 4, 2010
    Applicant: FUJIFILM Corporation
    Inventors: Kazufumi Omura, Hirotaka Sato, Tadahiro Ooishi
  • Patent number: 7641990
    Abstract: Non-magnetic powder of particles for non-magnetic lower layer applications is provided that enables a multilayer coating type magnetic recording medium having good surface smoothness to be obtained. The particles are iron compound particles having a long axis with a standard geometrical deviation, as obtained from a transmission electron microscope image, that is greater than 1.5, and a short axis with a standard geometrical deviation, as obtained from a TEM image, that is greater than 1.35. The iron compound particles may be hematite or iron oxyhydroxide.
    Type: Grant
    Filed: June 23, 2006
    Date of Patent: January 5, 2010
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Shinichi Konno, Toshihiko Ueyama, Kenichi Inoue, Takayuki Yoshida, Ken Inoue
  • Publication number: 20090087686
    Abstract: An aspect of the present invention relates to a magnetic recording medium comprising a coating layer on a nonmagnetic support, wherein the coating layer comprises a nonmagnetic layer comprising a nonmagnetic powder and a binder and a magnetic layer comprising a ferromagnetic powder and a binder in this order, the nonmagnetic support comprises a main component in the form of a resin obtained by mixing and/or copolymerizing a polyester and a polymer having compatibility with the polyester, has a glass transition temperature of equal to or higher than 80° C. but less than 125° C., and has a heat absorption peak, based on enthalpy relaxation, ranging from 0.5 to 2.0 J/g. Another aspect of the present invention relates to a method of manufacturing a magnetic recording medium.
    Type: Application
    Filed: September 29, 2008
    Publication date: April 2, 2009
    Applicant: FUJIFILM Corporation
    Inventors: Katsuhiko MEGURO, Masatoshi Takahashi
  • Patent number: 7494728
    Abstract: A magnetic tape comprising a non-magnetic support, a magnetic layer containing magnetic powder which is formed on one side of the non-magnetic support, a primer layer containing non-magnetic powder which is formed between the non-magnetic support and the magnetic layer, and a backcoat layer containing non-magnetic powder which is formed on the other side of the non-magnetic support, wherein the magnetic layer contains the magnetic powder which comprises plate, granular or ellipsoidal magnetic particles with a particle diameter of 5 to 50 nm, and has a thickness of 0.09 ?m or less, and wherein at least one of the primer layer and the backcoat layer contains non-magnetic plate particles with a particle diameter of 10 to 100 nm.
    Type: Grant
    Filed: March 10, 2003
    Date of Patent: February 24, 2009
    Assignee: Hitachi Maxell, Ltd.
    Inventors: Sadamu Kuse, Tsugihiro Doi, Tetsutaro Inoue, Mikio Kishimoto
  • Publication number: 20090042064
    Abstract: The present invention relates to non-magnetic particles for non-magnetic undercoat layer of magnetic recording medium, comprising: hematite particles; an inner coating layer comprising a phosphorus-containing inorganic compound which is formed on a surface of the respective hematite particles; and an outer coating layer comprising an aluminum-containing inorganic compound which is formed on an outside of the inner coating layer comprising the phosphorus-containing inorganic compound.
    Type: Application
    Filed: August 8, 2008
    Publication date: February 12, 2009
    Applicant: TODA KOGYO CORPORATION
    Inventors: Seiji ISHITANI, Hiroko Morii, Kazuyuki Hayashi
  • Publication number: 20080187784
    Abstract: The invention provides a magnetic recording medium having a structure in which a magnetic layer containing magnetic particles and a binder is formed on a nonmagnetic layer containing nonmagnetic particles and a binder, wherein the binder contained in the nonmagnetic layer contains a polyurethane resin having 50 to 100 eq/t of metal phosphate groups and 800 to 1600 eq/t of unsaturated hydrocarbon groups in its molecule and obtained by reacting a polyester polyol (A) containing an aliphatic dicarboxylic acid as an acid component, an aromatic polyisocyanate compound (B) and a compound (C) having unsaturated hydrocarbon groups and a functional group which reacts with an isocyanate group and a molecular weight of 500 or less, and the nonmagnetic layer has good dispersibility even by using fine nonmagnetic particles and can ensure satisfactory coating film strength even at a radiation dose of 3 Mrad or less.
    Type: Application
    Filed: February 5, 2008
    Publication date: August 7, 2008
    Applicants: TOYO BOSEKI KABUSHIKI KAISHA, TDK CORPORATION
    Inventors: Kuniyuki DOI, Tetsuo KAWAKUSU, Hiroyuki TANAKA, Kazunori TAMAZAKI
  • Publication number: 20080182135
    Abstract: A magnetic recording medium is provided that comprises a non-magnetic support and, in order thereabove, a radiation-cured layer cured by exposing a layer comprising a radiation curing compound to radiation, and a magnetic layer comprising a ferromagnetic powder dispersed in a binder, the radiation-cured layer comprising an inorganic powder that has been surface treated with a silane coupling agent.
    Type: Application
    Filed: January 25, 2008
    Publication date: July 31, 2008
    Applicant: FUJIFILM CORPORATION
    Inventors: Yuichiro MURAYAMA, Hiroshi HASHIMOTO
  • Patent number: 7378679
    Abstract: A patterned substrate includes a laminated pattern having laminated patterns that are formed by drying droplets containing a pattern formation material. A lower layer pattern contains lyophilic microparticles that are lyophilic with respect to droplets that form an upper layer pattern.
    Type: Grant
    Filed: December 12, 2005
    Date of Patent: May 27, 2008
    Assignee: Seiko Epson Corporation
    Inventor: Naoyuki Toyoda
  • Patent number: 7357997
    Abstract: A powder for an underlayer of a coating-type magnetic recording medium comprises acicular iron oxide particles having an average major axis length in the range of 20-200 nm, has a specific surface area measured by the BET method of 30-100 m2/g and has a powder pH of not greater than 7. The underlayer powder preferably contains 0.1-5.0 wt. % of P and optionally contains an amount of R (where R represents one or more rare earth elements, defined as including Y) such that R/Fe expressed in atomic percentage (at. %) is 0.1-10 at. %. The iron oxide powder enhances the properties required of a powder for forming the underlayer of a multi-layer structure coating-type magnetic recording tape, most notably the surface smoothness and strength of the tape.
    Type: Grant
    Filed: April 2, 2003
    Date of Patent: April 15, 2008
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Kazuyuki Matsumoto, Kenichi Inoue, Ken Inoue
  • Patent number: 7348079
    Abstract: A magnetic recording medium is provided that has on a non-magnetic support, in order, a radiation-cured layer formed by curing a layer containing a radiation curing compound by exposure to radiation, a lower layer having a non-magnetic powder and/or a magnetic powder dispersed in a binder, and at least one magnetic layer having a ferromagnetic powder dispersed in a binder. The binder of at least the magnetic layer is a binder having a glass transition temperature of 100° C. to 200° C., and the magnetic layer has on its surface a number of micro projections having a height of 10 to 20 nm measured by atomic force microscopy (AFM) of 5 to 1,000/100 ?m2.
    Type: Grant
    Filed: December 3, 2003
    Date of Patent: March 25, 2008
    Assignee: FUJIFILM Corporation
    Inventors: Yuichiro Murayama, Hiroshi Hashimoto
  • Publication number: 20070231611
    Abstract: A magnetic recording medium including a substrate, a nonmagnetic layer containing nonmagnetic powder and a binder, and a magnetic layer containing ferromagnetic powder and a binder, in this order, wherein the nonmagnetic layer has a thickness of from 0.5 to 2.5 ?m, a specific surface area of from 20 to 120 m2/ml, a pore volume of from 0.15 to 0.40 ml/ml, and a median pore radius of from 3 to 16 nm, and the nonmagnetic layer has particles having an average particle diameter of from 4 to 14 nm on a magnetic layer side.
    Type: Application
    Filed: March 28, 2007
    Publication date: October 4, 2007
    Applicant: FUJIFILM Corporation
    Inventor: Kouichi Masaki
  • Publication number: 20070224456
    Abstract: A magnetic recording medium including: a nonmagnetic support; a smoothing layer containing a polymer; a nonmagnetic layer formed by coating a first solution containing nonmagnetic powder and a binder on the smoothing layer and drying the coated first solution; and a magnetic layer formed by coating a second solution containing ferromagnetic powder, inorganic powder and a binder on the nonmagnetic layer and drying the coated second solution, in this order.
    Type: Application
    Filed: March 27, 2007
    Publication date: September 27, 2007
    Applicant: FUJIFILM Corporation
    Inventors: Naoto Murao, Youhei Aritoshi
  • Patent number: 7238438
    Abstract: A powder for an underlayer of a coating-type magnetic recording medium, which powder comprises flat-acicular iron oxide particles having an average major axis length of 20–200 nm, a short axis cross-section taken perpendicularly to the long axis that has a long width and a short width, and a short axis cross-section ratio defined as the ratio of the long width to the short width that is greater than 1.3 and substantially uniform in the long axis direction, the powder having a specific surface area measured by the BET method of 30–100 m2/g. The underlayer powder preferably contains 0.1–5.0 wt % of P and, optionally, an amount of R(R representing one or more rare earth elements, defined as including Y) such that R/Fe expressed in atomic percentage (at. %) is 0.1–10 at. %.
    Type: Grant
    Filed: April 2, 2003
    Date of Patent: July 3, 2007
    Assignee: Dowa Mining Co., Ltd.
    Inventors: Kazuyuki Matsumoto, Kenichi Inoue, Ken Inoue
  • Patent number: 7166377
    Abstract: In one aspect, the magnetic recording medium comprises a nonmagnetic layer comprising a nonmagnetic powder and a binder and a magnetic layer comprising a ferromagnetic powder and a binder in this order on a nonmagnetic support. The quantity of metal ions comprised in the nonmagnetic powder is equal to or less than 40 ppm/g. In a second aspect, the magnetic recording medium comprises a nonmagnetic layer comprising a nonmagnetic powder and a binder and a magnetic layer comprising a ferromagnetic powder and a binder in this order on a nonmagnetic support. The abrasiveness of the magnetic layer against a ferrite bar is equal to or less than 2×10?5 ?m/m. In both aspects, the quantity of metal ions extracted from the magnetic layer is equal to or less than 0.5 ppm/m2·100 mL.
    Type: Grant
    Filed: May 23, 2005
    Date of Patent: January 23, 2007
    Assignee: Fuji Photo Film Co., Ltd.
    Inventor: Naoto Murao
  • Patent number: 7090936
    Abstract: The present invention provides a high recording density magnetic recording medium with excellent surface smoothness, as well as excellent electromagnetic conversion characteristics and durability. A magnetic recording medium comprising a lower non-magnetic layer containing at least a non-magnetic powder and a binder resin on a non-magnetic support, and an upper magnetic layer with a thickness of 0.2 ?m or less on said lower non-magnetic layer, wherein said lower non-magnetic layer contains an acicular powder of hydrated iron oxide as the non-magnetic powder, and said lower non-magnetic layer contains a fatty acid and a fatty acid amide. Preferably the acicular powder of hydrated iron oxide is goethite with an average long axial length of 0.15 ?m or less.
    Type: Grant
    Filed: March 27, 2003
    Date of Patent: August 15, 2006
    Assignee: TDK Corporation
    Inventors: Kenichi Kitamura, Takayoshi Kuwajima, Sadafumi Iijima
  • Patent number: 7056607
    Abstract: Provided is a magnetic recording medium permitting the controlling of backcoat layer transfer to a magnetic layer surface, a reduction in dropout even when employing microgranular magnetic material, as well as good running stability, durability, and storage properties. The magnetic recording medium has a magnetic layer with a ferromagnetic powder and a binder on one surface of a nonmagnetic support and a backcoat layer with a nonmagnetic powder and a binder on the other surface of the nonmagnetic support. The nonmagnetic powder is an acicular particle having a mean particle diameter of 5 to 300 nm, and the backcoat layer includes water-soluble cations in a quantity of 100 ppm or less and water-soluble anions in a quantity of 150 ppm or less.
    Type: Grant
    Filed: March 29, 2004
    Date of Patent: June 6, 2006
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Noboru Zinbo, Noriko Inoue