Journal
RHEOLOGICA ACTA
Volume 56, Issue 9, Pages 707-717Publisher
SPRINGER
DOI: 10.1007/s00397-017-1026-z
Keywords
Viscoelastic coating liquids; Operability window; Slot coating; Coating bead; Couette-Poiseuille flow
Categories
Funding
- National Research Foundation of Korea (NRF) - Korean government (MSIP) [NRF-2016R1A5A1009592]
- Ministry of Trade, Industry & Energy (MOTIE, Korea) [10067082]
Ask authors/readers for more resources
The viscoelastic-capillary model to predict approximately coating windows for the stable operations of viscoelastic coating liquids is derived using a lubrication approximation in slot coating processes. Pressure distributions and velocity profiles for viscoelastic liquids based on the Oldroyd-B and Phan-Thien and Tanner (PTT) models are solved in the coating bead region considering the Couette-Poiseuille flow feature and the pressure jumps at upstream and downstream menisci. Practical operating limits for the uniform coating of rheologically different liquids that are free from leaking and bead break-up defects are constructed under various conditions, incorporating the position of the upstream meniscus as an important indicator while determining limits. The shift of the uniform operating range shows different patterns for the Oldroyd-B liquid with a constant shear viscosity and the PTT liquid with a shear-thinning nature in comparison with the Newtonian case. The windows predicted by the simplified model are corroborated with experimental observations for one Newtonian and two viscoelastic liquids.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available