In recent years, polymer films used as fundamental materials in semiconductors and other advanced devices have attracted significant attention. These films are generally fabricated using the T-die casting method. However, defects such as streaks frequently occur during film formation. In this study, to elucidate the mechanism of streak formation caused by the temperature dependence of the molten resin, temperature distribution measurements of the molten resin were first conducted. The results revealed a temperature difference between the center and edges of the resin when streaks occurred. To investigate the influence of viscosity, the temperature dependence of viscosity was examined, and it was confirmed that a viscosity difference between the center and edges of the resin arises during streak formation. Therefore, Particle Image Velocimetry (PIV) analysis was employed to visualize the flow behavior during the film formation process, and by performing quantitative analysis of the velocity vectors, the mechanism of streak formation was discussed based on the flow characteristics.
Nishioka et al. (Wed,) studied this question.