Development of Tape Casting Technology of High Flexibility Sheet by Soft-Flocculated Slurry

Abstract

The tape casting process is widely used in various industrial processes. A plasticizer is added to a slurry to improve moldability and provide flexibility to a sheet. These results in quality instability and an increase in CO₂ emissions. A soft-flocculated slurry was generated in this work employing polyelectrolytes as a dispersion and a linear polymer with a charge reversal to the charge of the dispersant at both terminals as a soft-flocculant. A well-dispersed slurry was prepared by adding dispersant beforehand. After that, a soft-flocculant was added to the well-dispersed slurry. By adding soft-flocculant, the well-dispersed slurry was changed to a gel state because of the crosslinking of dispersant. The resultant gel was soft and could easily be changed into a liquid by shaking. The soft-flocculated slurry was optimized by selecting the appropriate agent and controlling the additive amount of the agent. A tape was casted using the doctor blade method. As a result, a thin tape could be cast without the use of a plasticizer using an optimized soft-flocculated slurry. The quality of this tape was comparable to that of a conventional method. Furthermore, the cast tapes showed high homogeneity and good flexibility resistance to bending use.

Graphical Abstract

Relation between the yield stress of slurries and additive amount of agent.