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    MAGNETIC RECORDING MEDIUM
    1.
    发明专利
    MAGNETIC RECORDING MEDIUM 未知

    公开(公告)号：CA1287836C

    公开(公告)日：1991-08-20

    申请号：CA565958

    申请日：1988-05-05

    Applicant: KAO CORP

    Inventor： OKADA TOMOYUKI ,  KANNEN NAOKI ,  NISHIMORI TADASHI ,  TSUSHIMA RIKIO

    IPC: C07C275/00 ,  C08G18/60 ,  G03G5/087

    Abstract: A magnetic recording meidum which comprises a non-magnetic support and a magnetic layer thereon comprising a binder and powder of a ferromagnetic substance dispersed in the binder, the binder comprising a crosslinked product of a polyurethane having an average molecular weight of 900 to 50,000 and comprising at least one unit of the formula (I): (I) in which R1, R2 and R4 each are an alkylene, R3 is a hydrocarbon group derived from a di-isocyanate compound and R5 is hydrogen or methyl, in one molecular thereof and having -OH, -NCO or -OOC-CR5=CH2 at both terminals of the main chain thereof, provided that the terminals of the main chain are not -NCO when the molecular weight of the polyu.rethane ranges from 900 to 10,000. The polyurehtane resin can be prepared by using as a starting material a polymerizable dihydorxyl compound of the general formula (II): (II) in which R1, R2 and R4 each are an alkylene, R3 is a hydrocarbon group and R5 is -H or -CH3.

    MAGNETIC RECORDING MEDIUM
    5.
    发明专利
    MAGNETIC RECORDING MEDIUM 失效

    公开(公告)号：JPS6430021A

    公开(公告)日：1989-01-31

    申请号：JP18473687

    申请日：1987-07-24

    Applicant: KAO CORP

    Inventor： OKADA TOMOYUKI ,  KANNEN NAOKI

    IPC: G11B5/702 ,  C09D5/23 ,  C09D175/00 ,  C09D175/04

    Abstract: PURPOSE:To improve durability by incorporating the crosslinked matter of a specific polyurethane resin as a binder into a magnetic layer. CONSTITUTION:The crosslinked matter of the polyurethane resin which has >=1 pieces of the parts expressed by formula I in one molecular chain, has any of OH, NCO or formula II at both terminals of the main molecular chain and is 10,000-50,000 in mol.wt. by gel permeation chromatography is incorporated as the binder into the magnetic layer. In formula I, R1, R2, R4 denote an alkylene group; R3 denotes a hydrocarbon group derived from a diisocyanate compd.; R5 denotes H or CH3. The durability is thereby improved.

    MAGNETIC RECORDING MEDIUM
    6.
    发明专利
    MAGNETIC RECORDING MEDIUM 失效

    公开(公告)号：JPS63220414A

    公开(公告)日：1988-09-13

    申请号：JP5372087

    申请日：1987-03-09

    Applicant: KAO CORP

    Inventor： OKADA TOMOYUKI ,  KANNEN NAOKI

    IPC: G11B5/702 ,  C09D5/23 ,  C09D127/04 ,  C09D127/06 ,  C09D175/14

    Abstract: PURPOSE:To obtain a magnetic recording medium contg. well dispersed magnetic powder and having satisfactory surface smoothness and durability by forming a magnetic layer contg. a specified binder, a specified ester compd. as a lubricant, a specified coupling agent and ferromagnetic fine powder and by irradiating the magnetic layer. CONSTITUTION:A binder contg. a specified compd. having (meth)acrylic unsatd. bonds such as a compd. represented by formula I, magnetic powder surface- treated with a specified coupling agent and a specified phosphoric ester such as a compd. represented by formula III and a specified ester compd. such as a compd. represented by formula II are incorporated into a magnetic layer. In the formula II, each or R4 and R5 is 1-25C straight chain or branched satd. alkyl group and R6 is 7-29C straight chain or branched (un)satd. alkyl group. In the formula III, R is 2-28C hydrocarbon or acyl group, Q is 2-4C alkylene group, (q) is 0 or an integer of 1-30 and L is 1, 1.5 or 2. The components are easily converted into a magnetic coating material having superior dispersibility and stability. When the coating material is applied, a magnetic layer having superior smoothness is formed.

    MAGNETIC RECORDING MEDIUM
    7.
    发明专利
    MAGNETIC RECORDING MEDIUM 失效

    公开(公告)号：JPS6342022A

    公开(公告)日：1988-02-23

    申请号：JP18466786

    申请日：1986-08-06

    Applicant: KAO CORP

    Inventor： OKADA TOMOYUKI ,  KANNEN NAOKI ,  ISHIKAWA AKIRA ,  YAMASHITA KAZUTAKA ,  TSUSHIMA RIKIO

    IPC: G11B5/702 ,  C09D5/23 ,  C09D175/00 ,  C09D175/04

    Abstract: PURPOSE:To obtain a magnetic layer having excellent dispersibility of a coating compd. and excellent smoothness and durability of the magnetic layer by dispersing >=1 kinds of coupling agents selected from the group consisting of a specific org. silane compd., etc., and fine ferromagnetic powder subjected to a surface treatment by a specific phosphate into a binder contg. a specific thermoplastic polyurethane resin. CONSTITUTION:The thermoplastic polyurethane resin having 5,000-40,000 number average mol.wt. analyzed by gel permeation chromatography, >=200kg/cm breaking strength in a tension test of 100mm/min tension speed, 100-400% breaking elongation, >=150kg/cm 100% modulus, and >=40 deg.C glass transition temp. analyzed by dynamic viscoelasticity measurement is incorporated into the binder. The magnetic layer is formed by dispersing >=1 kinds of the coupling agents selected from the group consisting of the org. silane compd., etc., having a hydrolyzable alkoxy silane group in one molecule and the fine ferromagnetic powder subjected to the surface treatment by >=1 kinds of the phosphates selected from the group consisting of the phosphate having the structure expressed by the formula, etc., in an inert org. solvent into the above-mentioned binder.

    MAGNETIC RECORDING MEDIUM
    8.
    发明专利
    MAGNETIC RECORDING MEDIUM 失效

    公开(公告)号：JPS61198418A

    公开(公告)日：1986-09-02

    申请号：JP3850585

    申请日：1985-02-27

    Applicant: KAO CORP

    Inventor： KANNEN NAOKI ,  TSUSHIMA RIKIO ,  YAMASHITA KAZUTAKA ,  OKADA TOMOYUKI

    IPC: G11B5/702 ,  C09D5/23 ,  C09D175/00 ,  C09D175/04 ,  C09D175/06 ,  C09D175/12

    Abstract: PURPOSE:To improve magnetic powder dispersibility, durability and surface smoothness by using a specific polyurethane resin as a binder. CONSTITUTION:The polyurethane resin having at least >=1 of an ammonium salt and/or amine salt of a COOH group in the molecular chain is used. A magnetic recording medium is produced by coating a magnetic paint for which the polyurethane resin is used as the binder and to which pulverous ferromagnetic powder and additive, etc. are added together with an org. solvent, on a non- magnetic substrate and drying the coating. The ratio of the binder and the pulverous ferromagnetic powder is 10-100pts.wt., more preferably 20-50pts.wt. by 100pts.wt. pulverous ferromagnetic powder. The mechanical strength and wear resistance are not enough if the ratio of the binder is below 10pts.wt. The magnetic powder density in the magnetic layer decreases and the satisfactory performance (reproduced output, etc.) as the magnetic recording medium is not obtainable if the ratio of the binder is increased to 100pts.wt. or above.

    MAGNETIC RECORDING MEDIUM
    9.
    发明专利
    MAGNETIC RECORDING MEDIUM 失效

    公开(公告)号：JPH10177713A

    公开(公告)日：1998-06-30

    申请号：JP31331097

    申请日：1997-11-14

    Applicant: KAO CORP

    Inventor： KANNEN NAOKI ,  TSUSHIMA RIKIO ,  YAMASHITA KAZUTAKA ,  OKADA TOMOYUKI

    IPC: C08L75/04 ,  C09D5/23 ,  C09D175/04 ,  G11B5/702

    Abstract: PROBLEM TO BE SOLVED: To improve surface smoothness, dispersibility of a magnetic powder and durability while holding mechanical properties by using a polyurethane resin having one or more ammonium salts of COOH groups as a binder. SOLUTION: The number average mol.wt. of the polyurethane resin used is 5000 to 50000, and the compounding ratio of the polyurethane resin to a ferromagnetic fine powder is preferably by weight, 10 to 100 of the resin to 100 of the ferromagnetic fine powder. It is preferable that the ferromagnetic fine powder has /g specific surface area. As for the polyurethane resin, any polyurethane resin having isocyanate groups on both molecular ends, having hydroxyl groups on both molecular ends, or having one isocyanate group on one molecular end and a hydroxyl group on the other end can be used as far as the resin has the polar groups above described in the molecular chain. The polyurethane resin may contain one or more other polar groups as polar groups except for ammonium salt of COOH groups in the molecular chain.

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