Kao Corporation

Shigemi Wakabayashi

Akira Shiga

Noriyuki Kitaori

Osamu Yoshida

Hirohide Mizunoya

Kenji Kaida

Yuzo Matsuo

Katsumi Sasaki

Takehiro Tsutsumi

Hiroshi Ikeda

Kuniyasu Kawabe

Hideo Kobayashi

Koji Azuma

Yukihiro Nakano

Tadashi Sakuma

Tetsuya Ueno

Michitaka Sawada

Masayuki Narita

Hideki Yanagi

Makoto Sakakibara

Tadashi Matsui

An aqueous dispersion of polymer particles of a water-insoluble vinyl polymer containing a hydrophobic dye, wherein the water-insoluble vinyl polymer is prepared by polymerizing a monomer composition comprising an alicyclic (meth)acrylate, a salt-forming group-containing monomer, and a monomer copolymerizable with the alicyclic (meth)acrylate and the salt-forming group-containing monomer; and an ink comprising the aqueous dispersion. The aqueous dispersion is excellent in, for instance, storage stability, and the ink is excellent in, for instance, printing reliability, solvent resistance, water resistance and character quality.

Water-based ink

A water-based ink containing an aqueous dispersion of polymer particles of a water-insoluble polymer having an alkyl group of at least 20 carbon atoms in its side chain, and a hydrophobic dye. The water-based ink of the present invention can be suitably used as, for instance, an ink for inkjet recording, and the like.

A water-based ink comprising an aqueous dispersion of polymer particles comprising a polymer obtained by a solution polymerization, a bulk polymerization method or a suspension polymerization method, and a fluorescent colorant. The water-based ink can be suitably used as a water-based ink for inkjet recording and the like.

An oil-soluble dye prepared by subjecting a water-soluble dye having at least one group selected from the group consisting of sulfonate group and carboxyl group in its molecule to amidation: a water-based ink comprising the oil-soluble dye: and a process for preparing an oil-soluble dye, comprising halogenating a water-soluble dye having at least one group selected from the group consisting of sulfonate group and carboxyl group in its molecule, and thereafter subjecting the resulting halogenated water-soluble dye to amidation. The Oil-soluble dye of the present invention can be suitably and favorably used for inks for inkjet recording, inks for ball-points pens, inks for markers, toners, paints such as lacquers, inks for felt pens, and the like.

Aqueous ink for ink-jet printing comprises an emulsion of fine polymer particles and contains at least one compound selected from an amino acid or a salt thereof and the like.

Aqueous ink for ink-jet printing

A system for magnetic contact duplication by transferring an information signal recorded on a mother tape onto a blank tape, wherein the mother tape and the blank tape each includes at least one magnetic thin film having columns of magnetic grains grown obliquely, the column gradient .theta..sub.B1 of the magnetic grains in an uppermost magnetic thin film of the blank tape being smaller than the column gradient .theta..sub.M1 of the magnetic grains in an uppermost magnetic thin film of the mother tape, the mother tape and blank tape are superposed such that the column growth direction of the magnetic grains in the uppermost magnetic thin film of the mother tape and the column growth direction of the magnetic grains in the uppermost magnetic thin film of the blank tape intersect and such that these uppermost magnetic films face each other, and a bias magnetic field is applied from the substrate side of the blank tape.

System for magnetic contact duplication

A metal deposition magnetic recording medium comprising a support and at least one magnetic layer formed thereon by deposition, said recording medium having a residual magnetic flux density and a coercive force which satisfy the relationships of (1) and (2): ##EQU1## Br: Residual magnetic flux density H.sub.CV : Coercive force in the vertical direction

Magnetic recording medium

An aqueous pigment ink is provided made of a pigment, a dispersant, water, and a water-soluble solvent, wherein the dispersant contains a copolymer of a monomer (a) represented by formula (A), and one or more monomers (b) selected from the group consisting of compounds represented by formulae (B) and (C): ##STR1## Wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, AO, m.sub.1, m.sub.2, n, M.sub.1, M.sub.2 and Y are as defined herein that gives improved jettability, storage stability and printing characteristics.

Aqueous ink of pigment type

A metal film type magnetic recording medium in which the saturated magnetic flux density is high and iron having a good corrosion resistance is applied. The magnetic layer comprises metal films formed, in order on a base film, each containing iron, cobalt and nickel as main components.

Magnetic recording medium comprising successive magnetic metallic films

A treating method of a liner material for a magnetic recording medium according to the present invention is a treating method of a liner material which is to be bonded to the inside of a case storing therein a magnetic disk, and is characterized in that at least 0.1 wt %, based on the saturated water content of the liner material, of a liquid having a boiling point of 50.degree. to 200.degree. C. is added to the liner material, and is then dried. A treating apparatus of a liner material for a magnetic recording medium according to the present invention is an apparatus for executing the treating method described above, and comprises a feeder for feeding a belt-like liner material, a wetting device for allowing the liner material fed out from the feeder to contain a liquid, a dryer for drying the liner material containing the liquid, and a winder for taking up the dried liner material, wherein the liner material delivered from the winder passes through the wetting device and the dryer and is taken up by the winder.

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Wakayama, Japan

Shigemi Wakabayashi