A new polyurethane resin containing at least one phosphoric acid group and its use in a magnetic coating formulation and a magnetic recording medium
申请人:KYOWA HAKKO KOGYO CO., LTD.
公开号:EP0367667A2
公开(公告)日:1990-05-09
A magnetic coating formulation is composed principally of magnetic particles and a binder. At least a portion of the binder is a polyurethane resin newly synthesized from a reactant mixture of specific phosphorus compound, epoxy compound, isocyanate compound and polyfunctional hydroxy compounds. The reactant mixture may optionally contain a chain extender. The new polyurethane resin contains one phosphoric acid group or one residual group derived from phosphoric acid per 3,000-200,000 number average molecular weight of the polyurethane resin, and has a number average molecular weight of 4,000-150,000. A magnetic recording medium with a magnetic coating layer formed from the magnetic coating formulation is also disclosed. The magnetic coating layer features not only excellent dispersion of magnetic particles, in other words, excellent magnetic characteristics but also superb durability.
磁性涂层配方主要由磁性颗粒和粘合剂组成。粘合剂中至少有一部分是由特定磷化合物、环氧化合物、异氰酸酯化合物和多官能羟基化合物的反应混合物新合成的聚氨酯树脂。反应混合物可选择含有扩链剂。新的聚氨酯树脂每 3,000-200,000 个平均分子量中含有一个磷酸基团或一个由磷酸衍生的残余基团,平均分子量为 4,000-150,000 。还公开了一种磁性记录介质,其磁性涂层层由磁性涂层配方形成。该磁性涂层层不仅具有出色的磁性颗粒分散性(换句话说,具有出色的磁性特征),还具有超强的耐久性。