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The Effect of Bead Vacuum on Slot Die Coating

  • H.-M. Chang , C.-C. Lee and T.-J. Liu
Published/Copyright: April 6, 2013
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International Polymer Processing
From the journal International Polymer Processing Volume 24 Issue 2

Abstract

The effect of bead vacuum on the minimum wet thickness obtained on horizontal and vertical slot die coatings was experimentally examined using a flow visualization technique. The commercial software package FLOW3D was used to simulate the two-dimensional coating flow. Macroscopic material balances were applied to estimate the effect of bead vacuum. Applying vacuum on the coating bead was found to reduce the minimum wet thickness and increase the maximum coating speed, with the effect on horizontal slot die coating being more pronounced. Visual observations revealed that with increasing vacuum, the upstream meniscus against the moving web was pulled back significantly for a low-viscosity solution, and the dynamic contact angle was reduced for a high-viscosity solution. The observed upstream wetting length for a low-viscosity solution subject to bead vacuum was consistent with the prediction using macroscopic balances. The sizes of coating beads predicted by FLOW3D were generally larger than those observed from flow visualization. Coating failures caused by high bead vacuum could be predicted with the aid of numerical simulations.

∗ Mail address: Ta-Jo Liu, Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan 30043 ROC. E-mail:

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Received: 2008-08-19
Accepted: 2009-01-07
Published Online: 2013-04-06
Published in Print: 2009-05-01

© 2009, Carl Hanser Verlag, Munich

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  5. A Novel Dilatometer for PVT Measurements of Polymers at High Cooling – and Shear Rates
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https://doi.org/10.3139/217.2219

Articles in the same Issue

  1. Contents
  2. Contents
  3. Regular Contributed Articles
  4. Modeling the Temperature Development of Wall-slipping Polymers in Single-screw Channels
  5. A Novel Dilatometer for PVT Measurements of Polymers at High Cooling – and Shear Rates
  6. Analysis of Heat Transfer in PVC Profiles during the Extrusion Calibration/Cooling Step
  7. Study on the Bleeding Mechanism of Slip Agents in a Polypropylene Film using Molecular Dynamics
  8. A Direct 3D Numerical Simulation Code for Extrusion and Mixing Processes
  9. The Resarch for Asphalt Modified with Phosphorus Trichloride/SBS
  10. The Effect of Bead Vacuum on Slot Die Coating
  11. Predicting the Yield Stress of Polymer Glasses Directly from Processing Conditions: Application to Miscible Systems
  12. Numerical Simulation of a Thermoviscoelastic Frictional Problem with Application to the Hot-Embossing Process for Manufacturing of Microcomponents
  13. A Design to Study Flow Induced Crystallization in a Multipass Rheometer
  14. Modeling of Melt Conveying in a Novel Screw-Nested Extruder
  15. Rheological and Thermal Properties of a Model System for PIM
  16. PPS-News
  17. PPS News
  18. Seikei Kakou Abstracts
  19. Seikei-Kakou Abstracts
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