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公开(公告)号：DE3300592A1
公开(公告)日：1984-07-12
申请号：DE3300592
申请日：1983-01-11
Applicant: MITSUI TOATSU CHEMICALS
Inventor： SEKIGUCHI HARUO , TAGAWA KIMITERU , OHSHIMA KAZUSHI , FUKUDA NOBUHIRO , SUDO KAZUFUYU , KOBAYASHI SADAO
IPC: C21B15/00
Abstract: The invention relates to a method of producing ferromagnetic iron powder, in which boron oxide or a borate, such as, for instance, zinc borate, is added to alpha -FeOOH or alpha -Fe2O3 and mixed therewith without dissolving the former, the resultant mixture is heated to 350 DEG C or above in a non-reducing atmosphere, and the mixture heated in this manner is then reduced.
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公开(公告)号：SG47438A1
公开(公告)日：1998-04-17
申请号：SG1996001402
申请日：1993-12-03
Applicant: MITSUI TOATSU CHEMICALS
Inventor： MORITA MORITSUGU , TAGAWA KIMITERU , ABE KENJI , MINETA NAOSHI , KUBO TAKAYUKI , KIBA SHIGEO , OHKAWADO ETSUO , TANABE KENJI
IPC: C08G73/10 , C09J7/00 , C09J9/02 , C09J179/08 , H01B3/30 , H01L23/495 , H01L21/60
Abstract: An insulating adhesive tape comprises a base supporting film and an adhesive layer formed on at least one surface thereof, said adhesive layer being formed of a thermoplastic polymer comprising a thermoplastic polyimide. The thermoplastic polymer has a glass transition temperature ranging from 180 DEG C to 280 DEG C and an elastic modulus ranging from 10 dyne/cm to 10 dyne/cm at 25 DEG C, said modulus including a value ranging from 10 dyne/cm to 10 dyne/cm at a temperature between 250 DEG C and 300 DEG C.
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公开(公告)号：JPH04205913A
公开(公告)日：1992-07-28
申请号：JP33003590
申请日：1990-11-30
Applicant: MITSUI TOATSU CHEMICALS
Inventor： TAGAWA KIMITERU , TAKAHASHI SEIICHI , KOBA SHIGEO , SUDA SATORU
IPC: G11B5/712 , C09D5/23 , C09D127/04 , C09D127/06 , C09D175/06
Abstract: PURPOSE:To obtain a magnetic recording medium fit for high density magnetic recording by using ferromagnetic metal particles surface-coated with a ferrite compd. contg. divalent Co and trivalent Fe and having spinel structure. CONSTITUTION:Ferromagnetic metal particles surface-coated with a ferrite compd. contg. divalent Co and trivalent Fe and having spinel structure are used. The particles have satisfactory oxidation stability and maintain high saturation magnetization even in environmental deterioration or after a weather resistance test. When a magnetic layer is formed with the particles and a binder, a high rate of filling of the particles is attained in the magnetic layer and a magnetic recording medium having superior oxidation stability, maintaining high saturation magnetization and fit for high density recording can be obtd.
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公开(公告)号：JPH03228829A
公开(公告)日：1991-10-09
申请号：JP2224590
申请日：1990-02-02
Applicant: MITSUI TOATSU CHEMICALS
Inventor： HASHIMOTO MITSUYOSHI , FUKUDA NOBUHIRO , TAGAWA KIMITERU , MORITA KIYOTAKE
IPC: C01G49/02
Abstract: PURPOSE:To obtain fine goethite having a uniform distribution of particle size by supplying a solution of ferrous salt and alkali aq. solution to a bubble tower type reactor of specified structure and introducing oxidative gas the having oxygen partial pressure controlled to a specified value or higher to the reactor for oxidation. CONSTITUTION:A bubble tower type reactor 100 of vertical cylindrical shape is equiped with an air supplier 1 and perforated plate 2 in the lower part thereof and with a pressure controller 3 at the ventilation outlet. A solution of ferrous salt (e.g. aq. solution of ferrous sulfate) and alkali aq. solution (e.g. aq. solution of sodium hydroxide) are supplied through a feeder 6 to the reactor 100 to effect neutralization reaction. Then oxidative gas (e.g. compressed air) having >0.21atm oxygen partial pressure is introduced from the feeder 5 to the tower to effect oxidation reaction. Thereby, goethite having 100-200m /g specific surface area which satisfies the performance as the magnetic recording material for high definition television is obtained.
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公开(公告)号：JPH03174704A
公开(公告)日：1991-07-29
申请号：JP19777990
申请日：1990-07-27
Applicant: MITSUI TOATSU CHEMICALS
Inventor： TAGAWA KIMITERU , TAKAHASHI SEIICHI , UTSUNO NORITOSHI , UMEHARA HIDEKI , HAYASHI FUJIO , KOBA SHIGEO , SUDA SATORU
Abstract: PURPOSE:To improve oxidation stability and to maintain high saturated magnetization against deterioration of an environment by simultaneously neutralizing cobalt and iron in slurry in which iron-base oxyhydroxide particles are dispersed, and immediately forming gel generated directly as spinel compound as particle surface film. CONSTITUTION:The bivalent ions of cobalt and the trivalent ferric ions are simultaneously neutralized in slurry in which iron-base oxyhydroxide particles are dispersed, and gel generated directly as spinel compound is formed as film on the surfaces of the particles. Further, after ferromagnetic metal particles are formed to be obtained by heating, reducing, they are smoothly oxidized to stop the igniting property to form ferrite film having spinel structure on the surfaces of the particles. Thus, excellent oxidation stability is obtained, and even if an environment is deteriorated, highly saturated magnetization can be maintained.
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Patent Agency Ranking
公开(公告)号：JPH03102261A
公开(公告)日：1991-04-26
申请号：JP15663890
申请日：1990-06-16
Applicant: MITSUI TOATSU CHEMICALS
Inventor： ONOBUSA MITSUO , HASHIMOTO MITSUYOSHI , TAGAWA KIMITERU , HAGIWARA MICHIRO
Abstract: PURPOSE:To trace a change with time of a composition sequentially and to enable automatic control of the change of the composition by repeating sequentially and automatically operations from the collection of a fluid sample into a treating vessel to the preliminary treatment, analysis and discharge thereof and preparation for a subsequent analysis. CONSTITUTION:The content in a tank C-1 in a process of reaction is collected into a treating vessel R. The vessel R is weighed W, and when it reaches a predetermined weight, a cock V-1 is closed. The vessel R is heated H and then diluted water is injected therein. An agitating vane and a platinum electrode for titration which are fitted to a plate B are lowered into a sample solution in the vessel R and an electrode potential is read continuously by a microcomputer through a potentiometer E. A standard solution in a bottle C-2 is injected into the vessel R through a syringe pump P-4 and the titration is conducted. The microcomputer computes a rate of oxidation by using the quantity of the standard solution. The diluted water is released from slender holes of a showering S and thereby the inside of the vessel R is washed. Simultaneously, a suction nozzle N for discharge is inserted into the bottom part of the vessel R and a discharge pump P-5 is operated to discharge water. The pump P-5 is stopped a prescribed time later and the nozzle N, the electrode and the agitating vane are drawn up.
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公开(公告)号：JPH0323225A
公开(公告)日：1991-01-31
申请号：JP15671189
申请日：1989-06-21
Applicant: MITSUI TOATSU CHEMICALS
Inventor： HASHIMOTO MITSUYOSHI , IWASAKI KOZO , TAGAWA KIMITERU
IPC: C01G49/00
Abstract: PURPOSE:To obtain goethite reduced in the changes with the lapse of time until the conclusion of reaction in the number of particles and specific surface area, increased in specific surface area, and having uniform particle size distribution by carrying out rapid oxidation directly after the initiation of reaction at the time of oxidizing a hydroxide formed by allowing an aqueous alkali to react with an aqueous solution of ferrous salt. CONSTITUTION:In a method for producing goethite by oxidizing a suspension of hydroxide prepared by allowing an aqueous solution of ferrous salt and an aqueous alkali to react with each other by means of an oxidizing gas, rapid oxidation is carried out based on the curve of the change in the rate of oxidation from Fe ions to Fe ions with the lapse of time directly after the initiation of the reaction, by which acicular crystals having 100-120m /g specific surface area and uniform particle size distribution (sigmaL/L
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公开(公告)号：JPH01260624A
公开(公告)日：1989-10-17
申请号：JP9003188
申请日：1988-04-12
Applicant: MITSUI TOATSU CHEMICALS
Inventor： TAKAHASHI SEIICHI , SAKATA KENJI , SEKIGUCHI HARUO , KOBA SHIGEO , TAGAWA KIMITERU
IPC: G11B5/702 , C09D5/23 , C09D175/00 , C09D175/04
Abstract: PURPOSE:To improve signal input/output characteristics and signal noise ratio of regenerated signal by forming a magnetic recording film consisting of polythiourethane resin having specific thiol groups, a polyhydric isocyanate crosslinking agent and magnetic particles on a supporting body. CONSTITUTION:A magnetic recording film is formed on a supporting body, said film consisting of polythiourethane resin having at least >=0.01 equivalent of thiol group in 1,000g resin, polyhydric isocyanate crosslinking agent and magnetic powder. The required amount of thiol groups contained is >=0.01 equivalent, and more preferably 0.05-10.0 equivalent, so as to improve the dispersibility of magnetic powder as well as to maintain the characteristics of polyurethane resin that it has large elongation and high strength. Thus, the dispersion state of the magnetic powder in the coating material can be improved, which results in excellent input/output characteristics and high signal/ noise.
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公开(公告)号：JPS6484601A
公开(公告)日：1989-03-29
申请号：JP24088387
申请日：1987-09-28
Applicant: MITSUI TOATSU CHEMICALS
Inventor： TAGAWA KIMITERU , OSHIMA KAZUFUMI , TAKAHASHI SEIICHI , SUDOU KAZUFUYU
Abstract: PURPOSE:To enhance magnetic characteristics and to increase the stability against deterioration of magnetic characteristics by a method wherein a specific quantity of aluminum and boron is contained in the ferromagnetic metal powder which is mainly composed of iron. CONSTITUTION:Aluminum and boron are contained in the ferromagnetic metal powder which is mainly composed of iron. The quantity of aluminum and the boron to be contained is Al/Fe=0.001-0.20, B/Fe=0.0005-0.10 in the weight ratio with iron. The aluminum and the boron are abundantly present on the surface of particles. The material containing transition metal such as Ni, Co, Cu, Mn, Zn, Cr and the like can also be utilized excellently as the metal composi tion besides the aluminum and the boron above-mentioned. As a result, the magnetic characteristics of the above-mentioned metal powder can be enhanced, and the stability against the deterioration in the magnetic characteristics can also be increased.
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公开(公告)号：JPS6333509A
公开(公告)日：1988-02-13
申请号：JP17670886
申请日：1986-07-29
Applicant: MITSUI TOATSU CHEMICALS
Inventor： TSUMURA RYUICHIRO , OSHIMA KAZUFUMI , TAGAWA KIMITERU , MURAISHI TERUO
IPC: B22F9/22
Abstract: PURPOSE:To produce fine hexagonal cobalt particles having uniform grain sizes at a high yield by subjecting cobalt acetate contg. water of crystallization to a dehydration heat treatment, then heating the same in a hydrocarbon medium and reducing the cobalt acetate by pressurized hydrogen. CONSTITUTION:The cobalt acetate tetrahydrate is heated for about 10-20hr at about 100-250 deg.C under a reduced pressure to eliminate part or the whole of the water of crystallization contained therein. The cobalt acetate is then dispersed into the hydrocarbon medium (heptane, octane, etc.) until the initial concn. attains about 1-50wt%, then the cobalt acetate is reduced in the heated state by the hydrogen dissolved under the pressurization. The pressure of the hydrogen at this time is maintained under about 0.5-300kg/cm , the reaction temp. at about 150-350 deg.C and the reaction time for about 0.5-20hr. The reaction is carried out under stirring. The hexagonal cobalt is thereby obtd. at approximately 10% reaction yield and the particles thereof are as fine as 0.01-1mu grain size. The prepd. hexagonal cobalt is adequately usable as a magnetic material for perpendicular magnetic recording medium.
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