フラットダイの実験解析及びスケールアップ則

抄録

The flow of polymer melt in a flat die was analyzed theoretically by using a computer simulation and the relationship between the theoretical and experimental results was investigated.
As for the pressure drop in the die, the theoretical results agreed with the experimental ones for different kinds of dies. But with respect to the residence time distribution of polymer melt in the die, especially in case of coat-hunger type die, the theoretical results were slightly different from the experimental ones near the edge of die. As the uniformity of polymer melt depends on die lip clearance, the exact correspondence between theoretical and experimental results could not be obtained. But the theoretical analysis is very useful to evaluate the uniformity of a flat die.
By using the theoretical equations and dimensionless analysis, the scale-up rule considering the pressure distribution, residence time distribution and uniformity index was presented. We can obtain a basic consideration for design of a flat die by means of computer simulation technique, and the experimental results of both smaller flat die and the scale-up rule can be used for efficient design of larger flat die.