DOWA Electronics Materials Co.

Okayama-shi, Japan

DOWA Electronics Materials Co.

Okayama-shi, Japan
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Patent
Dowa Electronics Materials Co. | Date: 2017-05-17

To improve weather resistance of an RFID tag containing a paper substrate having an antenna circuit formed on the surface thereof. An RFID tag substrate containing a paper substrate having an eluted chloride ion amount per unit mass (1 g) according to the following item (A) of 0.100 mg or less, having formed on a surface thereof a conduction circuit:(A) a specimen of the paper substrate having an area corresponding to an A4 size (210 297 mm) determined in ISO 216 is broken into small pieces each of 100 mm^(2) or less; the small pieces are entirely placed in a polypropylene vessel; 50 mL of water having an electric conductivity of 0.2 mS/m or less is added thereto to immerse the small pieces entirely into the water; after allowing to stand at 23C 2C for 1 hour, the water is filtered with a membrane filter to recover a filtrate; and the filtrate is analyzed by an ion chromatography method to obtain a chloride ion (Cl^(-)) concentration in the filtrate, from which a total chloride ion amount eluted into 50 mL of the water is obtained, and is divided by the mass (g) of the specimen of the paper substrate to provide a value, which is designated as the eluted chloride ion amount per unit mass.


Patent
DOWA Electronics Materials Co. and Dowa F tec Co. | Date: 2017-08-09

There is provided a ferrite powder for bonded magnets having a high iHc value usable even in a low temperature environment, a method for producing the same, and a bonded magnet using the ferrite powder and having high iHc value which can be used even in a low temperature environment, wherein a specific surface area is 2.20 m^(2)/g or more and less than 3.20 m^(2)/g; a compression density is 3.30 g/cm^(3) or more and less than 3.60 g/cm^(3), and a compressed molding has a coercive force of 3250 Oe or more and less than 3800 Oe.


Patent
Dowa Electronics Materials Co. and Dowa F tec Co. | Date: 2017-08-09

There is provided a ferrite powder for bonded magnets capable of producing ferrite bonded magnets with high BH_(max), excellent in MFR when converted to a compound, with high p-iHc, wherein an average particle size of particles obtained by a dry laser diffraction measurement is 5 m or less, a specific surface area is 1.90 m^(2)/g or more and less than 3.00 m^(2)/g, a compression density is 3.40 g/cm^(3) or more and less than 3.73 g/cm^(3), and a compressed molding has a coercive force of 2800 Oe or more and less than 3250 Oe.


Patent
DOWA Electronics Materials Co. | Date: 2017-07-12

There is provided an inexpensive bonding material, which can be easily printed on articles to be bonded to each other and which can suppress the generation of voids in the bonded portions of the articles to be bonded to each other, and a bonding method using the same. In a bonding material of a copper paste which contains a copper powder containing 0.3 % by weight or less of carbon and having an average particle diameter of 0.1 to 1 m, and an alcohol solvent, such as a monoalcohol, a diol, a triol or a terpene alcohol, the content of the copper powder is in the range of from 80 % by weight to 95 % by weight, and the content of the alcohol solvent is in the range of from 5 % by weight to 20 % by weight.


Problem To provide a technique having high industrial practicality for providing a transparent conductive coated film that is excellent in conductivity, light transmissibility, haze characteristics, and adhesiveness. Solution A method for producing a silver nanowires ink, containing adding a viscosity modifier and a water-soluble acrylic-urethane copolymer resin, to an aqueous solvent or a mixed solvent of water and an alcohol having silver nanowires dispersed therein. The content of the water-soluble acrylic-urethane copolymer resin with respect to the total amount of the silver nanowires ink may be from 0.05 to 2.0% by mass. The content of silver with respect to the total amount of the silver nanowires ink is preferably from 0.05 to 1.0% by mass. The content of the viscosity modifier with respect to the total amount of the silver nanowires ink is preferably from 0.01 to 1.0% by mass. The viscosity of the silver nanowires ink is preferably controlled to a range of from 1 to 100 mPas.


Patent
Dowa Electronics Materials Co. | Date: 2017-02-08

[Problem] To provide a Fe-Co alloy powder suitable for an antenna, the powder having a high saturation magnetization s and a controlled coercive force Hc, and providing an extremely large and a sufficiently small tan (). [Means for Resolution] When introducing an oxidizing agent into an aqueous solution containing Fe ions and Co ions to generate crystal nuclei and cause precipitation and growth of a precursor having Fe and Co as components, Co in an amount corresponding to 40% or more of the total amount of Co used for the precipitation reaction is added to the aqueous solution at a time after the start of the crystal nuclei generation and before the end of the precipitation reaction to obtain the precursor, and then a dried product of the precursor is reduced to obtain a Fe-Co alloy powder. This Fe-Co alloy powder has a mean particle size of 100 nm or less, a coercive force Hc of 52.0 to 78.0 kA/m, and a saturation magnetization s of 160 Am^(2)/kg or higher.


Patent
DOWA Electronics Materials Co. | Date: 2017-01-18

In a fine silver particle dispersing solution wherein 30 to 75 % by weight of fine silver particles, which are coated with an organic acid having a carbon number of 5 to 8 or a derivative thereof and which have an average particle diameter of 1 to 100 nm, are dispersed in a water-based dispersion medium which is a solvent containing water as a main component, the fine silver particle dispersing solution containing ammonia and nitric acid, there is added 0.15 to 0.6 % by weight of a surface regulating agent, which preferably contains a polyether-modified polydimethylsiloxane and a polyoxyethylene alkyl ether or a polyether, or 0.005 to 0.6 % by weight of an antifoaming agent which is preferably a silicone antifoaming agent.


Patent
DOWA Electronics Materials Co. | Date: 2017-03-15

A bonding material of a silver paste contains: fine silver particles having an average primary particle diameter of 1 to 200 nm, each of the fine silver particles being coated with an organic compound having a carbon number of not greater than 8, such as sorbic acid; and a solvent mixed with the fine silver particles, wherein a diol, such as an octanediol, is used as the solvent and wherein a triol having a boiling point of 200 to 300 C, a viscosity of 2,000 to 10,000 mPa at 20C and at least one methyl group, such as 2-methylbutane-2,3,4-triol or 2-methylbutane-1,2,4-triol, is mixed with the solvent as an addition agent.


Patent
DOWA Electronics Materials Co. | Date: 2017-04-05

A bonding material includes: fine silver particles having an average primary particle diameter of 1 to 50 nm, each of the fine silver particles being coated with an organic compound having a carbon number of not greater than 8, such as hexanoic acid; silver particles having an average primary particle diameter of 0.5 to 4 m, each of the silver particles being coated with an organic compound, such as oleic acid; a solvent containing a primary alcohol solvent and a terpene alcohol solvent; and a dispersant containing a phosphoric acid ester dispersant (or a phosphoric acid ester dispersant and an acrylic resin dispersant), wherein the content of the fine silver particles is in the range of from 5 wt% to 30 wt%, and the content of the silver particles is in the range of from 60 wt% to 90 wt%, the total content of the fine silver particles and the silver particles being not less than 90 wt%, and wherein the bonding material further includes a sintering aid of a monocarboxylic acid having an ether bond.


Patent
University of Tokyo and Dowa Electronics Materials Co. | Date: 2017-04-26

Provided are: a magnetic -form iron oxide nanopowder which is a novel magnetic iron oxide nanopowder having magnetic polarization and spontaneous electric polarization and having physical properties similar to those of half-metals; and a process for producing the magnetic nanopowder. The magnetic powder has a composition represented by Fe_(2)O_(3) and has a crystal structure belonging to the monoclinic system.

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