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121. 发明专利

JPH02193314A MAGNETIC DISK 失效
公开(公告)号：JPH02193314A
公开(公告)日：1990-07-31
申请号：JP1125889
申请日：1989-01-20
申请人： FUJI PHOTO FILM CO LTD
发明人： KATO MIKIHIKO , ENDO YASUSHI , YAMADA YASUYUKI , NAGASHIMA YASUO
IPC分类号： G11B5/706 , C09D5/23 , C09D127/04 , C09D127/06 , C09D175/06 , G11B5/82
摘要： PURPOSE:To improve traveling durability of a magnetic disk at low temp. by specifying the coefft. of dynamic loss of the magnetic layer to a specific range. CONSTITUTION:The magnetic layer essentially comprising ferromagnetic metal powder (e.g. Fe-Ni powder) and a binder resin (A) is provided on a nonmagnetic supporting substance to constitute the magnetic disk. The coefft. of dynamic loss factor (tandelta) of the magnetic layer is specified to 2X10 - 8X10 at 110Hz with increasing temp. from -5 to 15 deg.C by 2 deg.C/min. The resin A used for the magnetic layer comprises three components, vinyl chloride copolymer having polar functional groups such as -COOM (M represents H or metal) in its molecule, polyurethane having two or more -OH groups and trifunctional polyisocyanate. The disk is manufactured by punching a master plate and then heat treating at a desired temp.

122. 发明专利

JPH01211214A MAGNETIC RECORDING MEDIUM AND PRODUCTION THEREOF 失效
公开(公告)号：JPH01211214A
公开(公告)日：1989-08-24
申请号：JP3390888
申请日：1988-02-18
申请人： FUJI PHOTO FILM CO LTD
发明人： NAGAO MAKOTO , YAMANAKA HIDEO , YAMADA YASUYUKI , MORITA KAZUHIKO
IPC分类号： G11B5/66 , G11B5/64 , G11B5/667 , G11B5/73 , G11B5/738
摘要： PURPOSE:To obtain a magnetic recording medium which simultaneously satisfies good magnetic characteristic wand traveling durability by providing flat parts which consist of thin films and exist interspersedly in island shapes and parts which are plasma-etched to recessed shapes on the surface of a high-polymer substrate and forming a thin ferromagnetic metallic film layer thereon. CONSTITUTION:The flat parts 2 which exist interspersedly in the island shapes and consist of the thin films 4 of metals, carbon, oxides or nitrides are provided by sputtering, ion plating, vacuum deposition, etc., in a reduced atmosphere on the high-polymer substrate 1. The surface thereof is then subjected to the plasma etching treatment in the reduced pressure atmosphere, by which the org. polymer uncoated with the metals, carbon, oxides or nitrides is carried away as volatile molecules and the recessed parts 3 are obtd. The thin ferromagnetic metallic film 5 is formed by vapor deposition, sputtering or ion plating on the substrate on which the flat parts 2 and the recessed parts 3 are formed in such a manner. The magnetic recording medium which simultaneously satisfies the good magnetic characteristics and traveling durability is thus obtd.

123. 发明专利

JPH0123856B2 失效
公开(公告)号：JPH0123856B2
公开(公告)日：1989-05-09
申请号：JP2974181
申请日：1981-03-02
申请人： FUJI PHOTO FILM CO LTD
发明人： YAMADA YASUYUKI , AKASHI GORO , TSUJI NOBUO , MUKODA YOSHIHITO , FUJAMA MASAAKI
IPC分类号： G11B5/842 , G11B5/702 , G11B5/84

124. 发明专利

JPS6479916A MAGNETIC RECORDING MEDIUM 失效
公开(公告)号：JPS6479916A
公开(公告)日：1989-03-24
申请号：JP23800587
申请日：1987-09-22
申请人： FUJI PHOTO FILM CO LTD
发明人： YAMANAKA HIDEO , NAGAO MAKOTO , YAMADA YASUYUKI , MORITA KAZUHIKO
IPC分类号： G11B5/72 , C10M177/00 , C10N40/18 , G11B5/64 , G11B5/66 , G11B5/725
摘要： PURPOSE:To prevent the generation of the deposits on a head and to enhance traveling durability by cleaning the surface of a protective layer, then providing a lubricating layer thereon to impregnate an org. lubricating agent to the interliner thereof. CONSTITUTION:A thin magnetic metallic film is provided on a nonmagnetic substrate and the protective layer essentially consisting of carbon is provided thereon. The surface of this protective layer is cleaned and the lubricating layer contg. the org. lubricating agent is provided thereon to impregnate the org. lubricating agent into the interliner. At least one kind of the metal selected from the group consisting of Cr, Mn, Mo, Nb, Ta, Ti, V, and W is added to the protective layer and the content thereof is specified to a 0.5-5% range. An alkaline detergent, neutral detergent and org. solvent are used for cleaning the protective layer.

125. 发明专利

JPS63273212A MAGNETIC RECORDING MEDIUM 失效
公开(公告)号：JPS63273212A
公开(公告)日：1988-11-10
申请号：JP10641987
申请日：1987-05-01
申请人： FUJI PHOTO FILM CO LTD
发明人： YAMADA YASUYUKI , NAGAO MAKOTO , MORITA KAZUHIKO
IPC分类号： G11B5/72 , C09D5/23 , C09D7/12 , G11B5/73
摘要： PURPOSE:To improve still durability at and under a high temp. and high humidity as well as a low temp. and low humidity by disposing fine particles which are introduced from a silica sol and have a specific grain size on the surface of a magnetic layer of a coating type magnetic recording medium. CONSTITUTION:The coating type magnetic layer is formed on a nonmagnetic base and the fine particles are disposed on the surface thereof. The fine silica particles introduced from the silica sol are used for the fine particles and the size of the particles is specified to 18-800mum. The reason for specifying the grain size lies in that there is no effect of improving the still life of the grain size if the silica is =800mum. Dispersibility is improved and a uniform coating liquid is obtd. if the fine particles are used as the silica sol. The uniformly dispersed fine silica particles are, therefore, obtd. if a silica sol soln. is coated on the surface of the magnetic layer and the solvent is thereafter removed by drying the coating. The still durability at and under the high temp. and high humidity as well as the low temp. and low humidity is thereby improved.

126. 发明专利

JPS6364627A MAGNETIC RECORDING MEDIUM 失效
公开(公告)号：JPS6364627A
公开(公告)日：1988-03-23
申请号：JP20799686
申请日：1986-09-05
申请人： FUJI PHOTO FILM CO LTD
发明人： ASAI TAKAMITSU , MASAKI KOICHI , YAMADA YASUYUKI , KAWAMATA TOSHIO
IPC分类号： G11B5/706 , C09D5/23 , C09D127/04 , C09D127/06 , C09D175/00 , C09D175/04
摘要： PURPOSE:To improve the degree of dispersion, reproduction output and CN and to suppress the change of coercive force with lapse of time by dispersing a ferromagnetic material which is a hexagonal flat plate having a high bulk density and has the axis of easy magnetization in the direction perpendicular thereto into a binder of a hydrophilic group-contg. resin, thereby constituting a magnetic layer. CONSTITUTION:The ferromagnetic material which is hexagonal-planar and has the axis of easy magnetization in the direction perpendicular to the flat plate face is dispersed into the binder of the hydrophilic group-contg. resin and the dispersion is coated on a nonmagnetic substrate to form the magnetic layer. Such ferromagnetic powder is subjected to a compaction treatment to adjust the bulk density to about 0.16 times the true density. The longer time is required for the dispersion and the reproduction output and CN are not enough if the bulk density exceeds the lower limit thereof. Particles are liable to be deformed and broken if the density exceeds the upper limit. The dispersion time of the ferromagnetic material is thereby shortened and the degree of dispersion, the reproduction output and CN are improved, by which the increase rate of the coercive force by the change thereof with lapse of time is extremely suppressed.

127. 发明专利

JPS62241128A MAGNETIC RECORDING MEDIUM 失效
公开(公告)号：JPS62241128A
公开(公告)日：1987-10-21
申请号：JP8427686
申请日：1986-04-14
申请人： FUJI PHOTO FILM CO LTD
发明人： RYOMO KATSUMI , OKUTSU TOSHIMITSU , TAKAHASHI MASATOSHI , YAMADA YASUYUKI
IPC分类号： C08G18/79 , C09D5/23 , C09D175/00 , C09D175/04 , G11B5/702
摘要： PURPOSE:To effectively prevent the generation of drop-out by providing a magnetic layer dispersed with ferromagnetic powder into a binder on a nonmagnetic base and using a polyisocyanate isocyanurate as a curing component for the binder. CONSTITUTION:This magnetic recording medium is formed by providing the magnetic layer dispersed with the ferromagnetic powder in the binder on the nonmagnetic base. The polyisocyanate isocyanurate is used as the curing component for the binder of the magnetic layer at a content of 1-50wt% of the total weight of the binder. Carbon black is incorporated into the magnetic layer. Electrification of a traveling system is thus decreased and the generation of the drop-out is effectively prevented.

128. 发明专利

JPS62202322A MAGNETIC RECORDING MEDIUM 失效
公开(公告)号：JPS62202322A
公开(公告)日：1987-09-07
申请号：JP4380986
申请日：1986-02-28
申请人： FUJI PHOTO FILM CO LTD
发明人： MIYOSHI TAKAHITO , INAMI HIROO , HANAI KAZUKO , YAMADA YASUYUKI
IPC分类号： G11B5/702 , C09D5/23 , C09D127/04 , C09D127/06 , C09D175/00 , C09D175/04 , G11B5/708
摘要： PURPOSE:To maintain the mu value on the surface of a magnetic layer at a specified level by using a polyurethane resin into which a specific ratio of polar groups are incorporated and using specific carbon black therein. CONSTITUTION:The binder for dispersing ferromagnetic powder is formed of the resin component contg. the polyurethane resin having at least one kind of polar groups among -COOM, -SO3M, -OSO3M and -PO(OM')2. M denotes a hydrogen atom or alkali metal atom, M' denotes hydrogen, alkali metal or lower hydrocarbon group. The resin component contg. the polyurethane resin has the polar groups at a ratio of one piece per 19,000-45,000 number average mol.wt. over the entire part of the resin component. The magnetic layer contains the carbon black having 90-150mmu average particle size. The use of such carbon black contributes not only to a decrease of the mu value of the initial period (right after the prepn. of the magnetic recording medium) but also to a reduction of the fluctuation of the mu value by repetitive running.

129. 发明专利

JPS6295723A MAGNETIC RECORDING MEDIUM 失效
公开(公告)号：JPS6295723A
公开(公告)日：1987-05-02
申请号：JP23230385
申请日：1985-10-19
申请人： FUJI PHOTO FILM CO LTD
发明人： HANAI KAZUKO , YAMADA YASUYUKI , MIYOSHI TAKAHITO
IPC分类号： C08G18/32 , C09D5/23 , C09D127/04 , C09D127/06 , C09D175/00 , C09D175/04 , C09D175/06 , G11B5/702 , G11B5/708 , G11B5/73
摘要： PURPOSE:To obtain a magnetic recording medium having excellent running durabiity by forming a magnetic layer contg. ferromagnetic powder dispersed into a binder contg. a specific polyurethane resin on a non-magnetic substrate. CONSTITUTION:The polyurethane resin which is expressed by formula I and has the repeating unit derived from diol is incorporated intot the binder of the magnetic recording medium having the nonmagnetic substrate and the magnetic layer contg. the ferromagnetic powder dispersed in the binder formed thereon. In the formula, R -R may be the same or different from each other and denote hydrogen atom, satd. or unstad. aliphat. group, arom. group, and alicyclic. group of 1-5C, at least three substituents among R -R are not hydrogen atoms. l Is 1-3, m is 0-2, n is 1-3, p is 1-3 integer. The unit expressed by formula I among the repeating units of the diol constituting the polyurethane resin is >=20mol% and the polyurethane resin is preferably incorporated in the binder at >=10wt% of the total weight of the binder.

130. 发明专利

JPS61264509A MAGNETIC RECORDING MEDIUM 失效
公开(公告)号：JPS61264509A
公开(公告)日：1986-11-22
申请号：JP10468585
申请日：1985-05-16
申请人： FUJI PHOTO FILM CO LTD
发明人： OGAWA HIROSHI , MIYOSHI TAKAHITO , FUJIYAMA MASAAKI , SAITO SHINJI , YAMADA YASUYUKI
IPC分类号： G11B5/702 , C09D5/23 , C09D175/08
摘要： PURPOSE:To form a double-layered magnetic recording medium having an excellent electromagnetic conversion characteristic by incorporating polycarbonate polyurethane therein as a binder. CONSTITUTION:The binder for the upper layer and/or the binder for the lower layer contains the polycarbonate polyurethane. The thickness of the magnetic layer is particularly preferably 0.5-2mu for the upper layer and particularly preferably 2.0-4.0mu for the lower layer. The polycarbonate polyurethane used is obtd. by condensing polyol, polyisocyanate and if necessary a chain extender. The polyurethane having 10,000-120,000 average mol.wt. can be utilized. The durability of a tape is deteriorated if the mol.wt. is smaller than said range and the solubility of the resin is deteriorated and such deterioration is undesirable from an industrial view point if the mol.wt. exceeds said range.

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