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公开(公告)号：JPH1055525A
公开(公告)日：1998-02-24
申请号：JP20971996
申请日：1996-08-08
Applicant: KAO CORP
Inventor： YAMASHITA KAZUTAKA , NAKAYAMA HIDEHIKO , ISHIKAWA AKIRA
IPC: C08G59/42 , C08L63/00 , C09D163/00 , G11B5/702 , G11B5/735
Abstract: PROBLEM TO BE SOLVED: To improve the characteristics of a magnetic coating material as a coating material and to obtain a magnetic recording medium having improved durability. SOLUTION: This magnetic recording medium l has one or more magnetic layers 4 on the substrate 2. Each of the magnetic layers 4 contains a binder having at least two epoxy groups in one molecule and having a number average mol.wt. of 5,000-50,000, a compd. having an ether skeleton as well as two or more carboxyl groups in one molecule and having a number average mol.wt. of 500-5,000 and a promoter.
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公开(公告)号：JPH09293230A
公开(公告)日：1997-11-11
申请号：JP10790996
申请日：1996-04-26
Applicant: KAO CORP
Inventor： ISHIKAWA AKIRA , NAKAYAMA HIDEHIKO , YAMASHITA KAZUTAKA
Abstract: PROBLEM TO BE SOLVED: To provide a magnetic recording medium which is excellent in electromagnetic conversion characteristic, and furthermore, excellent in preservation stability such as less deterioration of electromagnetic conversion characteristics at the time of retention. SOLUTION: This recording medium is constituted of a non-magnetic supporting body 2, a front layer 10 and a rear layer 20. The front layer 10 has an intermediate layer 3 on the front surface side of the non-magnetic supporting body 2 and a magnetic layer 4 as the uppermost layer. The rear layer 20 has a back coating layer 5 on the rear surface side of the non-magnetic supporting body 2. The magnetic layer 3 contains ferromagnetic metal powder and a binder. The amount of a solvent remaining in the front layer 10 is 5 to 1000ppm. The ferromagnetic metal powder consists essentially of iron and contains one or more elements, which belong to the IIIa group of the periodic table and contain lanthanoid, at a ratio of 0.8 to 20 pts.wt. with 100 pts.wt. of Fe atom. and the thickness of the magnetic layer 4 and the surface roughness at the center line of the magnetic layer 4 are 0.05 to 0.6μm and 1 to 5nm, respectively. Further, the amount of a solvent remaining in the rear layer 20 and the surface roughness at the center of the back coating layer 5 are 5 to 800ppm and 2 to 8nm, respectively.
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公开(公告)号：JPH09194767A
公开(公告)日：1997-07-29
申请号：JP1016496
申请日：1996-01-24
Applicant: KAO CORP
Inventor： ISHIKAWA AKIRA , NAKAYAMA HIDEHIKO , YAMASHITA KAZUTAKA , TOGASHI HIROYASU
IPC: C09D5/23 , C09D7/12 , C10M137/04 , C10M137/12 , C10N40/18 , G11B5/70 , G11B5/71 , G11B5/725
Abstract: PROBLEM TO BE SOLVED: To obtain a magnetic recording medium which can deal with the high-density recording with high persistency an is useful as a magnetic drum, a magnetic tape, a magnetic card or the like by allowing the magnetic layer on the substrate or on a layer formed on the surface side of the magnetic layer to contain a specific phosphorus compound. SOLUTION: In a magnetic recording medium comprising the substrate and the magnetic layer formed on the substrate, the magnetic layer or a layer formed on the surface side of the magnetic layer is allowed to contain a phosphorus compound having groups in which OH bonds to each of adjacent carbon atom for example, a compound bearing 2-4 OH groups in one molecule, for example, a compound of formula I [R and R are each a 2-4C (branched) alkylene; R and R are H, 1-30C (branched) alkyl, a 2-30C (branched) alkenyl, a 6-30C aryl; p and q are each 0-30, in the case that p=0, R is not H; in the case that q=0, R is not H] and a compound formula II}.
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公开(公告)号：JPH09180166A
公开(公告)日：1997-07-11
申请号：JP34107595
申请日：1995-12-27
Applicant: KAO CORP
Inventor： ISHIKAWA AKIRA , NAKAYAMA HIDEHIKO , YAMASHITA KAZUTAKA
IPC: C08F216/14 , C08F16/14 , C08F20/02 , C08F222/06 , C09D129/00 , C09D129/10 , C09D133/02 , C09D135/00 , G11B5/702
Abstract: PROBLEM TO BE SOLVED: To improve the dispersibility of magnetic powder in a magnetic layer on a substrate and to improve the smoothness of the surface of a medium by incorporating a copolymer of methoxypolyethylene glycol vinyl ether with maleic anhydride into the magnetic layer. SOLUTION: This magnetic recording medium has a substrate and a magnetic layer contg. magnetic powder formed on the substrate. The magnetic layer further contains a copolymer of methoxypolyethylene glycol vinyl ether with maleic anhydride. The number average mol.wt. of the copolymer is preferably 8,000-50,000 and the water content of the magnetic powder is preferably 0.3-2.0wt.%.
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公开(公告)号：JPH09167333A
公开(公告)日：1997-06-24
申请号：JP33002795
申请日：1995-12-19
Applicant: KAO CORP
Inventor： ISHIKAWA AKIRA , NAKAYAMA HIDEHIKO , YAMASHITA KAZUTAKA
Abstract: PROBLEM TO BE SOLVED: To attain an excellent travelling property and to increase the output by forming a back coat layer so as to contain a acicular Mn-containing magnetic iron oxide powder in a magnetic recording medium having a magnetic layer and the back coat layer. SOLUTION: The magnetic recording medium 1 has a supporting body 2, the magnetic layer 3 provided on the surface of the supporting body 2 and the back coat layer 4 provided on the rear side of the supporting body 2. And, an intermediate layer 5 is provided at need between the supporting body 2 and the magnetic layer 3. In this constitution, the back coat layer 4 provided on the rear side of the supporting body 2 is a layer formed by applying a back coating material on the supporting body 2. The back coating material is a coating material containing a Mn-containing non-magnetic iron oxide powder having a specific form and concretely a coating material consisting essentially of the Mn-containing non-magnetic iron oxide powder, a binder and a solvent is preferably used.
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Patent Agency Ranking
公开(公告)号：JPH08255335A
公开(公告)日：1996-10-01
申请号：JP5915395
申请日：1995-03-17
Applicant: KAO CORP
Inventor： ISHIKAWA AKIRA , NAKAYAMA HIDEHIKO , YAMASHITA KAZUTAKA
Abstract: PURPOSE: To provide a magnetic recording medium excellent in output characteristics and overwriting characteristics by forming 1st and 2nd magnetic layers on a substrate and incorporating platy magnetite powder into the 2nd magnetic layer. CONSTITUTION: This magnetic recording medium 1 has a substrate 2 and plural magnetic layers 3 formed on the substrate 2. The magnetic layers 3 are a 1st magnetic layer 3a as the top layer and a 2nd magnetic layer 3b adjacent to the top layer. A back coating layer 4 is disposed if necessary. The substrate 2 may be any of magnetic and nonmagnetic substrates but a nonmagnetic substrate is preferable and a flexible polymer film or disk or a substrate of a nonmagnetic metal such as Cu, Al or Zn, glass, porcelain, etc., is used. This magnetic recording medium has satisfactory surface smoothness and is excellent in output (C/N) characteristics and overwriting characteristics.
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公开(公告)号：JPH08235571A
公开(公告)日：1996-09-13
申请号：JP23585095
申请日：1995-09-13
Applicant: KAO CORP
Inventor： ISHIKAWA AKIRA , NAKAYAMA HIDEHIKO , YAMASHITA KAZUTAKA
Abstract: PURPOSE: To provide a magnetic recording medium having good surface smoothness and excellent output (C/N) characteristics and overwriting characteristics. CONSTITUTION: This magnetic recording medium 1 consists of a nonmagnetic supporting body 2 and plural numbers of magnetic layers 3 formed on the nonmagnetic supporting body 2. The plural magnetic layers 2 include a first magnetic layer 3a as the uppermost layer and a second magnetic layer 3b adjacent to the first magnetic layer 3a. The second magnetic layer 3b in this magnetic recording medium contains a soft magnetic powder having 10-130m /g specific surface area.
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公开(公告)号：JPH08180379A
公开(公告)日：1996-07-12
申请号：JP32885694
申请日：1994-12-28
Applicant: KAO CORP
Inventor： ISHIKAWA AKIRA , NAKAYAMA HIDEHIKO , YAMASHITA KAZUTAKA
Abstract: PURPOSE: To obtain a magnetic recording medium having satisfactory surface smoothness and excellent in output (C/N) characteristics and overwriting characteristics. CONSTITUTION: In the magnetic recording medium 1 with a nonmagnetic substrate 2 and plural magnetic layers 3 disposed on the substrate 2 and including a 1st magnetic layer 3a as the top layer and a 2nd magnetic layer 3b adjacent to the 1st magnetic layer 3a, the 1st magnetic layer 3a contains a group of powders including magnetic powder and the 2nd magnetic layer 3b contains a group of powders including soft magnetic powder. The total surface area α1 of all the powders contained in the 1st magnetic layer 3a per unit volume os >120 to /cm , the total surface area α2 of all the powders contained in the 2nd magnetic layer 3b per unit volume is >80 to /cm and the ratio of α1 to α2 is >0.5 to
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公开(公告)号：JPH08180375A
公开(公告)日：1996-07-12
申请号：JP32549794
申请日：1994-12-27
Applicant: KAO CORP
Inventor： ISHIKAWA AKIRA , NAKAYAMA HIDEHIKO , YAMASHITA KAZUTAKA
Abstract: PURPOSE: To obtain a magnetic recording medium having satisfactory surface smoothness and excellent in output (C/N) characteristics and overwriting characteristics. CONSTITUTION: In the magnetic recording medium 1 with a nonmagnetic substrate 2 and plural magnetic layers 3 disposed on the substrate 2 and including a 1st magnetic layer 3a as the top layer and a 2nd magnetic layer 3b adjacent to the 1st magnetic layer 3a, soft magnetic oxide powder, acicular nonmagnetic powder and a binder are incorporated into the 2nd magnetic layer 3b.
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公开(公告)号：JPH0845062A
公开(公告)日：1996-02-16
申请号：JP17570594
申请日：1994-07-27
Applicant: KAO CORP
Inventor： ISHIKAWA AKIRA , NAKAYAMA HIDEHIKO , YAMASHITA KAZUTAKA
Abstract: PURPOSE:To obtain a magnetic recording medium capable of high density recording and excellent especially in output characteristics. CONSTITUTION:This magnetic recording medium consists essentially of a magnetic substrate 1, a nonmagnetic layer 2 formed on the substrate 1 and a magnetic layer 3 formed on the nonmagnetic layer 2. The nonmagnetic layer 2 contains acicular nonmagnetic powder, the magnetic layer 3 contains acicular ferromagnetic powder and the ratio of the axial ratio (average major axis size/average minor axis size) of the ferromagnetic powder to that of the nonmagnetic powder is 0.5-10. The ratio of the average major axis size of the ferromagnetic powder to that of the nonmagnetic powder is >=0.4.
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