1.
    发明专利
    未知

    公开(公告)号:DE59803043D1

    公开(公告)日:2002-03-21

    申请号:DE59803043

    申请日:1998-12-16

    Abstract: The present invention relates to a magnetic recording medium, comprising a non-magnetic support and at least one magnetic coating applied thereto, whereby said coating contains at least one finely distributed magnetic material dispersed in a binding agent. Said binding agent contains at least one polyurethane resin (PV, which can be obtained by cross-linking at least one polyisocyanate (A) with at least one polyurethane prepolymer (B) which is free of isocyanate groups and contains at least 3 active hydrogen atoms. The invention is characterised in that the polyurethane prepolymer (B) has at least two hydroxyl groups and at least one primary and/or secondary amino group. The invention also relates to a method for producing a magnetic recording medium, polyurethane prepolymers B) which are free of isocyanate and a method for the production and use thereof.

    4.
    发明专利
    未知

    公开(公告)号:DE59502989D1

    公开(公告)日:1998-09-03

    申请号:DE59502989

    申请日:1995-02-25

    Abstract: PCT No. PCT/EP95/00695 Sec. 371 Date Sep. 9, 1996 Sec. 102(e) Date Sep. 9, 1996 PCT Filed Feb. 25, 1995 PCT Pub. No. WO95/24443 PCT Pub. Date Sep. 14, 1995Magnetic powder and substrate material are separately recovered from finely chopped wastes of magnetic recording media consisting of a polymeric substrate and a magnetic layer present thereon in which finely divided magnetic powder is dispersed in crosslinked or uncrosslinked polymeric binder by treating the finely chopped wastes of magnetic recording media in a solution consisting of the potassium salt of a polyunsaturated fatty acid, or a biodegradable cleaning agent comprising phosphates, surfactants and a complexing agent, and one or more organic solvents or water while being subjected to mechanical action, and separately removing the magnetic powder from the substrate material by washing or sedimentation or in a magnetic separator.

    Materials suitable as crosslinkable binder components

    公开(公告)号:GB2285807B

    公开(公告)日:1998-04-29

    申请号:GB9500512

    申请日:1995-01-11

    Abstract: Preparation of materials (I) having an average molecular weight from 4000 to 30,000, obtainable by reacting 1) a polyurethane (II) comprising a) 1 mol of a diol (III) having an average molecular weight of from 400 to 4000, b) from 0.3 to 9 mol of an aliphatic or cycloaliphatic diol (IV) of 2 to 18 carbon atoms, c) from 0.3 to 9 mol of an aromatic diol (V) of 8 to 30 carbon atoms, d) from 0.01 to 1 mol of a trihydric alcohol (VI) of 3 to 18 carbon atoms, e) from 0.001 to 1 mol of a polyhydric alcohol (VII) of 3 to 14 carbon atoms which contains a tertiary amino group and f) an amount of a diisocyanate (VIII) of 6 to 30 carbon atoms such that the molar ratio of the isocyanate groups to the total number of hydroxyl groups in (III) to (VII) is from 1.05:1 to 1.4:1 with 2) a compound (IX) which contains one or more hydroxyl groups and one or more amino groups reactive toward isocyanate groups, the amount of (IX) being such that the number of reactive amino groups corresponds to the number of isocyanate groups in the polyurethane (II). The materials may be used as crosslinkable binder components for pigment-containing coatings, in particular for the production of magnetic recording materials.

    Materials suitable as crosslinkable binder components

    公开(公告)号:GB2286192B

    公开(公告)日:1998-04-29

    申请号:GB9500515

    申请日:1995-01-11

    Abstract: A material suitable as crosslinking binder component for pigment-containing coatings and having an average molecular weight of from 25,000 to 150,000, obtainable by reacting a polyurethane comprising a diol having a molecular weight between 400 and 4,000, an aliphatic or cycloaliphatic diol of 2-18 carbon atoms, an aromatic diol of 8-36 carbon atoms, a trihydric or polyhydric alcohol of 3-18 carbon atoms, a polyhydric alcohol of 3-40 carbon atoms containing a tertiary amino group, and a diisocyanate of 3-34 carbon atoms with a compound containing one or more hydroxyl groups and one or more amino groups reactive toward isocyanate groups. The materials may be used as crosslinkable binder components for pigment-containing coatings, in particular for the production of magnetic recording materials.

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