| 摘要 |
PURPOSE:To obtain the titled binder having excellent solubility in org. solvent, heat resistance and mechanical strength, which can be easily converted to a magnetic paint and capable of improving the dispersibility of magnetic powder by using polyurethane resin (PUR) of a specified composition. CONSTITUTION:The PUR can be obtained from polyester diol having a linear terminal hydroxyl group and/or polyether diol, 2-10C diols and 2,4- and/or 2,6-tolylenediisocyanate (TDI) and 15-40wt% TDI, PUR soluble in ketonic solvent and, if necessary, low-mol.wt polyisocyanate having >=2 NCO groups are incorporated into the PUR. The binder thus obtained has excellent solubility in ketonic solvent, mechanical property and heat resistance and also has excellent compatibility with other resins. Consequently, the binder can be used for a magnetic recording medium such as a magnetic tape, a magnetic disk, etc.
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