13results about "Coating by liquid dispersion" patented technology

A hexagonal ferrite magnetic powder is significantly more useful for achieving simultaneously both the enhancement of the recording density and the enhancement of the SNR of a magnetic recording medium. The hexagonal ferrite magnetic powder contains Bi at a Bi / Fe molar ratio in a range of 0.035 or less, has a saturation magnetization σs of 42.0 Am2 / kg or more and a Dx volume calculated based on the crystallite diameters of 1,800 nm3 or less. A method for producing hexagonal ferrite magnetic powder includes a step of performing a treatment of immersing hexagonal ferrite magnetic powder containing Bi in a solution having dissolved therein a compound X that forms a complex with Bi, so as to elute a part of Bi existing in the hexagonal ferrite magnetic powder into the solution.

The present invention provides hexagonal ferrite magnetic powder which is extremely useful in achieving both an increase in recording density and an increase in SNR of a magnetic recording medium, is crystalline and has a high saturation magnetization. The hexagonal ferrite magnetic powder contains Bi in a range of a Bi / Fe molar ratio of 0.035 or less, has a saturation magnetization σs of 42.0 Am 2 / kg or more, and a Dx volume of 1800 nm 3 or less, based on a microcrystal diameter. The magnetic powder can be produced by a method for producing hexagonal ferrite magnetic powder, comprising a process of immersing hexagonal ferrite magnetic powder containing Bi in a solution in which a compound X that forms a complex with Bi is dissolved, thereby performing a treatment of dissolving a part of the Bi present in the hexagonal ferrite magnetic powder into the solution.

Provided is a magnetic recording medium capable of suppressing narrowing of an effective recording width.　The magnetic recording medium is a tape-like magnetic recording medium, and comprises a substrate and a laminated film in the stated order. The laminated film includes, on the substrate in the following order, a soft magnetic layer containing a soft magnetic powder and a binder, and a hard magnetic layer containing a hard magnetic powder and a binder. The average thickness of the soft magnetic layer is 250 nm or greater, and the squareness proportion of the laminated film in the longitudinal direction of the magnetic recording medium is 35% or less.

Provided is a magnetic recording medium capable of achieving both an improvement of electromagnetic conversion characteristics and a reduction of running friction.　The magnetic recording medium is tape-shaped and comprises a base, and a magnetic layer containing magnetic particles. The average thickness of the magnetic recording medium is 5.30 μm or less. In a bearing curve created on the basis of measurement data of a magnetic layer-side surface obtained using an atomic force microscope, a difference Pk (10) between a maximum protrusion height and a height at an area ratio of 10% is 22.0-30.0 nm inclusive. The squareness ratio of the magnetic layer in the longitudinal direction of the magnetic recording medium is 0.35 or less.

[Subject] Provide a substitutional ε iron oxide magnetic particle powder and a method for producing a substitutional ε iron oxide magnetic particle powder, wherein a portion of the Fe sites of ε-Fe2O3 are replaced with other metal elements and the content of non-magnetic α-type iron-based oxides is reduced. [Solution] After neutralizing an acidic aqueous solution containing trivalent iron ions and ions of metals to replace a portion of the Fe sites to a pH of 2.0 or higher and 7.0 or lower, a silicon compound having a hydrolyzable group is added to a dispersion containing the generated oxyhydroxide containing the replacing metal element or a mixture containing oxyhydroxide and the hydroxide of the replacing metal element, and then the dispersion is neutralized to a pH of 8.0 or higher, maintained and aged, and the chemical reaction product of the silicon compound is coated on the oxyhydroxide containing the replacing metal element or the mixture of oxyhydroxide and the hydroxide of the replacing metal element and heated, thereby obtaining a substitutional ε iron oxide magnetic particle powder with a reduced content of α-type iron-based oxides.

The purpose of the present invention is to provide a magnetic recording medium that has excellent running stability even when stored in a high-temperature environment.　The present invention provides a magnetic recording medium in which, when dynamic viscoelasticity measurement is performed on the magnetic recording medium at a frequency of 10 Hz and a heating rate of 2°C / min, the average value A(E") of the loss elastic modulus E" in the temperature range of 60°C to 65°C is 0.06 GPa or less, and the average height Rpk of the protruding peaks measured using a non-contact profilometer using optical interference is 2.4 nm or less.

Product that features: - a recording layer (1008) which includes: - encapsulated nanoparticles (1010) each comprising exactly one magnetic nanoparticle encapsulated by an aromatic, polymer (1014) based encapsulation layer, and - a polymeric binder (1016) that binds the encapsulated nanoparticles (1010), - a sublayer (1006), wherein the recording layer (1008) is formed on the sublayer (1006), wherein the recording layer (1008) is not physically mixed with the sublayer (1006) in the product, such that an upper surface of the sublayer (1006) is substantially flat, with a modulation of less than 25% of the thickness of an interface between the sublayer (1006) and the recording layer, wherein the sublayer is electrically conductive to assist in the dissipation of a charge in the product, and - wherein the sublayer comprises encapsulated magnetic nanoparticles (1010) with a coercive force of less than 200 Oersted (Oe).

Provided is a magnetic recording medium capable of suppressing narrowing of an effective recording width.　The magnetic recording medium is a tape-like magnetic recording medium, and comprises a substrate and a laminated film in the stated order. The laminated film includes, on the substrate in the following order, a soft magnetic layer containing a soft magnetic powder and a binder, and a hard magnetic layer containing a hard magnetic powder and a binder. The average thickness of the soft magnetic layer is 250 nm or greater, and the squareness proportion of the laminated film in the longitudinal direction of the magnetic recording medium is 35% or less.

An object of the present technology is to provide a magnetic recording medium that has excellent travelling stability even when preserved in a high-temperature environment.The present technology provides a magnetic recording medium, in which an average value A(E″) of loss elastic moduli E″ in a temperature range of 60° C. to 65° C. when dynamic mechanical analysis is performed on the magnetic recording medium at a frequency of 10 Hz and a heating rate of 2° C. / min is 0.06 GPa or less, and an average height Rpk of protruding peaks measured using a non-contact profilometer using optical interference is 2.4 nm or less.

To provide a magnetic tape which can record and / or regenerate stored data desirably.SOLUTION: The present invention relates to a magnetic tape having a nonmagnetic supporting body and a magnetic layer containing ferromagnetic powders. The nonmagnetic supporting body is a polyamide supporting body. The ratio of deformation of the magnetic tape in the width direction to the deformation of the magnetic tape in the longer direction measured after a load is applied for 96 hours in the longer direction of the magnetic tape is 0.45 or smaller. The present invention also relates to a magnetic tape cartridge and a magnetic record regenerator including the magnetic tape.SELECTED DRAWING: None

Provided is a magnetic recording medium in which aggregation of magnetic particles is suppressed in a magnetic layer.　The magnetic recording medium is in tape-form and comprises a magnetic layer containing magnetic particles, a dispersant having an adsorption group, and a solvent. The absolute value of the difference between the dissolution parameter of the dispersant as calculated by the Fedors method from the structural formula excluding the adsorption group and the dissolution parameter of the solvent as calculated by the Fedors method is no greater than 0.50 (cal / cm3)1 / 2.

To provide a magnetic recording medium having a magnetic layer that contains ε-iron oxide powder, with which it is possible to exhibit excellent electromagnetic conversion characteristics when reproducing data having been recorded using an in-plane recording scheme.SOLUTION: Provided is a magnetic recording medium having a magnetic layer that contains ferromagnetic powder. The ferromagnetic powder is ε-iron oxide powder, a ratio (Hr(45°) / Hr(0°)) of Hr(0°) to Hr(45°) being 0.50 or less. The Hr(0°) is a residual coercive force Hr obtained by applying a pulse magnetic field with a pulse width of 0.76 ms in an in-plane direction of the magnetic recording medium, and the Hr(45°) is a residual coercive force Hr obtained by applying a pulse magnetic field with a pulse width of 0.76 ms to the magnetic recording medium, causing it to enter from a direction which is inclined 45° from the in-plane direction toward a vertical direction, with an angle in the in-plane direction of the magnetic recording medium defined as 0° and an angle in the vertical direction defined as 90°. Also provided are a magnetic tape cartridge and a magnetic recording-reproduction device that include the magnetic recording medium.SELECTED DRAWING: None

To provide a method for producing an iron-based oxide magnetic powder dispersion slurry having good dispersibility even in a medium alkali region to a weakly acidic region.SOLUTION: By adding, to a slurry containing iron-based oxide particles of ε type, a quaternary ammonium salt serving as a first dispersant and an alkali to increase the pH at 25°C to 11 or more, and then adding thereto an organic compound which has two or more carboxyl groups in a molecule serving as a second dispersant and in which other than the carboxyl groups, one or two kinds of hydroxyl groups and amino groups are bonded to a carbon which does not constitute the carboxyl groups, and setting the pH of the slurry at 25°C to 4 or more and less than 11. Thereby, given is an iron-based oxide magnetic powder dispersion slurry having good dispersibility in which the average secondary particle diameter of the iron-based oxide of ε type measured by a dynamic light scattering type particle size distribution measuring device is 65 nm or less.SELECTED DRAWING: None