Magnetic lithographic inks
    4.
    发明授权
    Magnetic lithographic inks 失效
    磁性平版印刷油墨

    公开(公告)号:US3054751A

    公开(公告)日:1962-09-18

    申请号:US78399758

    申请日:1958-12-30

    Applicant: IBM

    Abstract: A pigment for use in an oleophilic lithographic ink (see Group IV(a)) comprises particles of a magnetic material, e.g. gamma ferric oxide, natural and artificial magnetites and cobalt, nickel and barium ferrites, having a hydrophobic surface coating. The particles are rendered hydrophobic (i) by coating with a suitable resin, e.g. silicone, vinyl acetate or chloride, polyethylene, polyamide, phenolic, alkyd, coumarone-indene, epoxy, cyclized rubber, melamine, chlorinated paraffin or zein; (ii) by coating with a dyestuff by a laking procedure, e.g. a rhodamine tungstate-molybdate complex is formed in situ on the particles; (iii) by treatment with a phosphatizing or nitrating agent so as to provide roughened pigment particle surfaces; or (iv) by coating with certain surface active agents, viz. ricinoleic acid, dialkyl quarternary ammonium chloride/ethoxylated amine acetate mixtures, organic aluminium compounds and oil-soluble non-ionic ammonium compounds with or without subsequent treatment with NaOH. Examples are given.ALSO:An oleophilic lithographic ink contains, as a pigment, fine magnetic particles having a hydrophobic surface coating for reducing the emulsification tendencies of the ink resulting from the hydrophilic nature of the uncoated magnetic pigment particles. Magnetic materials specified are gamma ferric oxide, natural and artificial magnetites, unicrystalline iron, magnetic alloys, and cobalt, nickel and barium ferrites. The surfaces are coated as by treatment with a resinous material, a dye surfactant material, a reactive chemical giving rise to a phosphatizing or nitrating surface reaction or a certain surface active agent (see Group III). In one formation a litographic ink consists of gamma ferric oxide coated with ricinoleic acid, an isophthalic alkyd varnish, a black colourant base (i.e. impingement black in linseed oil), blue toner and paraffin oil. In another formulation the binder is a rosin-modified phenol-formaldehyde resin varnish and a cobalt drier is also added.

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