Hitachi Maxell, Limited

Hitachi Maxwell, Ltd.

Toshinobu Sueyoshi

Mikio Kishimoto

Masahiro Amemiya

Seigi Kawarai

Ryuzo Fukao

Kazuhiko Daido

Kyouichi Kohama

Shigeo Hirai

Wasao Takasugi

Akira Miyake

Seiichi Asada

Tetuya Nakazumi

Akira Kato

Yoshinori Yamamoto

Takanori Kamoto

Shinichi Kitahata

Haruo Andoh

Hisao Kanzaki

Susumu Kitaoka

Kaname Tamada

Yukihiro Hayashi

Noriaki Ohtani

Hikaru Ishida

Katsunori Tashita

Yusuke Hirai

The present invention provides an information carrier which has flat surfaces, is excellent in beautiful appearance and permits beautiful necessary printing, and a production process which permits easy and inexpensive production of such an information carrier. An IC chipand a coilconnected to the IC chip are embedded in a substratecomposed of a nonwoven fabric. The IC chip and the coil are held between two nonwoven fabrics produced according to a conventional production procedure. The laminate of the nonwoven fabrics is fed to a roller or a press and the two nonwoven fabrics are hot-pressed, whereby their mating surfaces are joined with or without an adhesive (including low-melting synthetic resin fiber) incorporated into the webs. After positioning of the coil in the thus obtained raw product of information carrier, the laminate of the nonwoven fabrics and cover sheets is cut to obtain an information carrier of predetermined shape and size.

Information carrier and process for production thereof

The present invention provides an information carrier which has flat surfaces, is excellent in beautiful appearance and permits beautiful necessary printing, and a production process which permits easy and inexpensive production of such an information carrier. An IC chip and a coil connected to the IC chip are embedded in a substrate composed of a nonwoven fabric. The IC chip and the coil are held between two nonwoven fabrics produced according to a conventional production procedure. The laminate of the nonwoven fabrics is fed to a roller or a press and the two nonwoven fabrics are hot-pressed, whereby their mating surfaces are joined with or without an adhesive (including low-melting synthetic resin fiber) incorporated into the webs. After positioning of the coil in the thus obtained raw product of information carrier, the laminate of the nonwoven fabrics and cover sheets is cut to obtain an information carrier of predetermined shape and size.

There is a flexible IC module utilizable for the production of contactless IC cards and a method for producing an information carrier using the flexible IC module. An IC chip and a coil are embedded in a flexible substrate comprising a nonwoven fabric or the like having compressibility in the thickness direction, self-pressure bonding property and resin impregnation property. This flexible IC module is produced in the following procedure. {circle around (1)} A first nonwoven fabric having compressibility in the thickness direction, self-pressure bonding property and resin impregnation property is placed on a bottom force . {circle around (2)} An IC chip and a coil are placed on the first nonwoven fabric after positioning them. {circle around (3)} A second nonwoven fabric is superposed on the IC chip and coil. {circle around (4)} A top force is pressed onto the second nonwoven fabric, and the first and second nonwoven fabrics, the IC chip and the coil are integrated by hot pressing.

Flexible IC module and method of its manufacture, and method of manufacturing information carrier comprising flexible IC module

A fluorescent marking composition containing particles of an organic material which has a glass transition temperature of at least 30.degree. C. and an average particle size of at least 30 nm, and emitting fluorescence in a visible light range, or absorbing infrared light having a wavelength of at least 700 nm and emitting a light in an infrared wavelength range, which composition is excellent in dispersion stability, light resistance, and heat and light resistance, and provides a mark which does not bleed.

Fluorescent marking composition and fluorescent mark formed by said

Magnetic powder, method for producing the same and use of the same

An acicular alloy base magnetic powder comprising iron and cobalt, which has an average particle long axis size of not larger than 0.25 .mu.m, an axial ratio of from 4 to 8, a cobalt content of from 8 to 50% by weight based on the weight of iron and saturation magnetization of at least 120 emu/g after being kept standing at the temperature of 60.degree. C. and relative humidity of 90% for a week, which has improved corrosion resistance and can provide a magnetic recording medium suitable for recording in the short wavelength range.

Acicular alloy magnetic powder

Acicular alloy containing magnetic recording medium

A magnetic recording medium with improved output characteristics and durability is provided by using magnetic powder comprising iron-containing particles each of which carries a compound containing aluminum and/or a compound containing silicon in such amounts that, in the whole magnetic powder, a weight ratio of silicon to iron is from 0.010:1 to 0.150:1, a weight ratio of aluminum to iron is from 0.040:1 to 0.150:1, and a weight ratio of aluminum to silicon is from 1:1 to 15:1.

Magnetic recording medium

Magnetic powder at least a part of particles of which have surface-adjacent layers comprising an aluminium-containing oxide of the corundum structure has high hardness so that a magnetic recording medium comprising a magnetic layer containing such magnetic powder has improved durability.

Magnetic powder and magnetic recording medium comprising the same

A process for preparing ferromagnetic particles comprising metallic iron as the major component by oxidizing Fe(OH).sub.2 in an aqueous medium adjusted to a pH of not less than 11 with gaseous oxygen to produce particles of .alpha.-FeOOH, optionally followed by dehydration of the .alpha.-FeOOH particles under heating to produce particles of .alpha.-Fe.sub.2 O.sub.3, and reducing the .alpha.-FeOOH or .alpha.-Fe.sub.2 O.sub.3 particles under heating, characterized in that (1) the aqueous medium at the oxidation step comprises at least one metal compound chosen from compounds of alkaline earth metals, zinc and aluminum and (2) the coating of a silicon compound is applied to the .alpha.-FeOOH or .alpha.-Fe.sub.2 O.sub.3 particles before the reduction step, whereby the ferromagnetic particles of metallic iron having enhanced magnetic characteristics are obtained.

Process for preparing ferromagnetic particles comprising metallic iron

A method for the production of uniform acicular metal magnetic particles comprising predominantly iron which have excellent magnetic characteristics and are useful as a recording element for a magnetic recording medium, said method comprising the steps of coating the surface of metal compound particles containing predominantly acicular iron oxyhydroxide or iron oxides with at least one member selected from the group consisting of an aluminum compound and a silicon compound, pelletizing the coated particles, and reducing the pellets with heating under reducing atmosphere, e.g. under hydrogen stream.

Method for production of metal magnetic particles

A process for preparing ferromagnetic iron particles comprising metallic iron as the major component by reduction of particles of an iron oxide under heating, characterized in that the iron oxide particles are provided with a first coating layer containing at least one metal compound chosen from compounds of aluminum, zinc and alkaline earth metals at the surfaces and a second coating layer containing at least one silicon compound thereon before the reduction, whereby the coated particles are prevented from sintering and breaking upon reduction so as to give ferromagnetic particles of metallic iron having excellent magnetic characteristics.

An improved magnetic recording medium is disclosed, particularly a magnetic tape suitable for sound recording and video recording, which comprises as a recording element a mixture of cobalt-containing iron oxide magnetic particles consisting essentially of ferromagnetic iron oxide particles containing cobalt and optionally a divalent iron in the most outer layer thereof, and .gamma.-ferric oxide particles in the ratio of 10:90 to 50:50 by weight, said mixture of cobalt-containing iron oxide magnetic particles and .gamma.-ferric oxide particles being applied to a substrate (e.g. a polyester film) with a binding agent. The magnetic recording medium has excellent electromagnetic transducing properties and improved charging properties and is useful for conventional magnetic recording apparatus used at normal position with high sensitivity in wide range of frequency.

Growing community of inventors

Kyoto, Japan

Toshinobu Sueyoshi