Transient behaviors of dual-layered patches for Newtonian liquids were numerically investigated in dual-layer slot coating processes for the first time using step-changed inlet flows. To further tune the leading and trailing edges in a patch cycle, startup and end lag times between the top and bottom layers were proposed, considering the flow state of a bottom-layer liquid in a coating bead region. Carefully chosen lag times significantly reduced the defects in the leading and trailing edges of a dual-layered patch. It was also found that a greater coating layer viscosity results in a greater amount of residue left on the die lips, which affects the next patch cycle.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) grants funded by the Ministry of Science and ICT (MSIT) of the Korea government (No. NRF-2016R1A5A1009592 and NRF-2021M3H4A6A01041234) and the Ministry of Trade, Industry & Energy (MOTIE, Korea) under the Industrial Technology Innovation Program (No. 20011712).
© 2022, Korean Society of Rheology.
- Edge formation
- Intermittent coating
- Liquid transfer
- Slot coating
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics