| 摘要 |
<p>PURPOSE:To provide excellent chipping resistance without back coating by incorporating a basic filler which adsorbs a basic indicator bromothymol blue in blue color to a polyester film of a nonmagnetic base. CONSTITUTION:The filler having the basicity to adsorb the basic indicator bromothymol blue in flue color is incorporated into the polyester film of the nonmagnetic base and a magnetic layer is formed on this film. The filler which exhibits the basicity is representatively Al2O3 and the reason for using the bromothymol blue as the basic indicator lies in that this indicator decolors at suitable pH and develops a color by being adsorbed to the filler in order to decide the normal/abnormal condition of the affinity of the polyester film and the filler. The amt. of the filler to be added is adequately <5wt.% and the size thereof is >=5m<2>/g, BET value.</p> |
