| 摘要 |
PURPOSE:To improve an electromagnetic conversion property without worsening a travelling stability by incorporating an ethylene oxide-propylene oxide block copolymer to a back coat layer. CONSTITUTION:The prescribed copolymer is the block polymer comprising ethylene oxide having a hydrophilic oxide component and propylene oxide having a hydrophilic oxide component. since said block copolymer comproses ethylene oxide having a relative hydrophilic group and propylene oxide having a relative hydrophobic group, the relative hydrophilic ethylene oxide component suitably adheres to the filling surface, while, the relative hydrophobic propylene oxide component has a good compatibility against the binding resin. By incorporating the prescribed copolymer to the titled medium, the dispersibility of the powders in the back coat layer is greatly improved. An aggregation of a filler is prevented, and the good surface smoothness of the back coat layer is obtd. |
