Ribbing instability in rigid and deformable forward roll coating flows

Je Hoon Lee; Sang Kwon Han; Joo Sung Lee; Hyun Wook Jung; Jae Chun Hyun

Korea-Australia Rheology Journal, Vol.22, No.1, 75-80, March, 2010

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Ribbing instability in rigid and deformable forward roll coating flows

Je Hoon Lee, Sang Kwon Han¹, Joo Sung Lee², Hyun Wook Jung^†, and Jae Chun Hyun

Department of Chemical and Biological Engineering, Korea University, Seoul 136-713, Korea
¹Surface Technology Research Group, POSCO, Gwangyang 545-090, Korea
²LG Chem/Research Park, Daejeon 305-380, Korea

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Dynamics and ribbing instability for Newtonian and viscoelastic liquids have been investigated in both rigid and deformable forward roll coating flows. Especially, the role of viscoelasticity of coating liquids and roll deformability or hardness on the coating flow has been scrutinized. Coating thickness at steady uniform states and wavelength and severity at unstable ribbing states have been measured, incorporating thickness measurement device and two-roll coating equipment. Relationship between wavelength and severity in ribbing instability strongly depends on the viscoelasticity as well as other operating conditions such as capillary number, coating gap, and roll deformability. Coating windows demarcating uniform and ribbing instability are considerably reduced by increasing viscoelasticity and decreasing roll deformability. In other words, ribbing is aggravated as the viscoelasticity of coating liquids that can generate the extensional property in film splitting region rises or roll deformability decreases, leading to higher severity and narrower wavelength.

Keywords:ribbing;forward roll coating;wavelength;severity;viscoelasticity;roll deformability;coating window

[References]

Benjamin DF, Roll Coating Flows and Multiple Roll Systems, Ph.D. thesis, University of Minnesota. (1994)
Benkreira, H., M.F. Edwards and W.L. Wilkinson, Chem. Eng. Sci., 57(15), 3025 (2002)
Carvalho MS, Roll Coating Flows in Rigid and Deformable Gaps, Ph.D. thesis, University of Minnesota. (1996)
Carvalho MS, Scriven LE, J. Fluid Mech., 339, 143 (1997)
Carvalho MS, Scriven LE, J. Comput. Phys., 151, 534 (1999)
Carvalho MS, Chem. Eng. Sci., 58(19), 4323 (2003)
Castillo M, Patera AT, J. Fluid Mech., 335, 323 (1997)
Chong YH, Gaskell PH, Kapur N, Chem. Eng. Sci., 62(15), 4138 (2007)
Cohen ED,Gutoff EB, Modern Coating and Drying Coating and Drying (1992)
Coyle DJ, The Fluid Mechanics of Roll Coating, Ph.D. thesis, University of Minnesota. (1984)
Dontula P, Pasquali M, Scriven LE, Macosko CW, Rheol. Acta, 36(4), 429 (1997)
Dontula P, Polymer Solutions in Coating Flows, Ph.D. thesis, University of Minnesota. (1999)
Fall C, Trans. ASME., 100, 462 (1978)
Gaskell PH, Kapur N, Savage MD, Phys. Fluids, 13, 1243 (2001)
Gokhale VV, J. Rheol., 25, 421 (1981)
Greener J, Sullivan T, Turner B, Middleman S, Chem. Eng. Commun., 5, 73 (1980)
Gutoff EB, Cohen ED, Coating and Drying Defects, John Wiley & Sons, New York. (1995)
Han SK, Shin DM, Park HY, Jung HW, Hyun JC, Eur. Phys. J. Special Topics, 166, 107 (2009)
Hao Y, Haber S, Int. J. Numer. Meth. Fl., 30, 635 (1999)
Hasegawa T, Sorimachi K, AIChE J., 39, 935 (1993)
Kistler SF, Scriven LE, Int. J. Numer. Meth. Fluids, 4, 207 (1984)
Kistler SF, Schweizer PM, Liquid Film Coating, Chapman & Hall, New York. (1997)
Middleman S, Fundamentals of Polymer Processing, McGraw-Hill, New York. (1977)
Mill CC, South GR, J. Fluid Mech., 28, 523 (1967)
Savage MD, AIChE J., 30, 999 (1984)
Lopez FV, Pauchard L, Rosen M, Rabaud M, J. Non-Newton. Fluid Mech., 103(2-3), 123 (2002)
Weinstein SJ, Ruschak KR, Ann. Rev. Fluid Mech., 36, 29 (2004)
Zevallos GA, Carvalho MS, Pasquali M, J. Non-Newton. Fluid Mech., 130(2-3), 96 (2005)

[Referenced By]

[Related Articles]

[1] Benjamin DF, Roll Coating Flows and Multiple Roll Systems, Ph.D. thesis, University of Minnesota. (1994)

[2] Benkreira, H., M.F. Edwards and W.L. Wilkinson, Chem. Eng. Sci., 57(15), 3025 (2002)

[3] Carvalho MS, Roll Coating Flows in Rigid and Deformable Gaps, Ph.D. thesis, University of Minnesota. (1996)

[4] Carvalho MS, Scriven LE, J. Fluid Mech., 339, 143 (1997)

[5] Carvalho MS, Scriven LE, J. Comput. Phys., 151, 534 (1999)

[6] Carvalho MS, Chem. Eng. Sci., 58(19), 4323 (2003)

[7] Castillo M, Patera AT, J. Fluid Mech., 335, 323 (1997)

[8] Chong YH, Gaskell PH, Kapur N, Chem. Eng. Sci., 62(15), 4138 (2007)

[9] Cohen ED,Gutoff EB, Modern Coating and Drying Coating and Drying (1992)

[10] Coyle DJ, The Fluid Mechanics of Roll Coating, Ph.D. thesis, University of Minnesota. (1984)

[11] Dontula P, Pasquali M, Scriven LE, Macosko CW, Rheol. Acta, 36(4), 429 (1997)

[12] Dontula P, Polymer Solutions in Coating Flows, Ph.D. thesis, University of Minnesota. (1999)

[13] Fall C, Trans. ASME., 100, 462 (1978)

[14] Gaskell PH, Kapur N, Savage MD, Phys. Fluids, 13, 1243 (2001)

[15] Gokhale VV, J. Rheol., 25, 421 (1981)

[16] Greener J, Sullivan T, Turner B, Middleman S, Chem. Eng. Commun., 5, 73 (1980)

[17] Gutoff EB, Cohen ED, Coating and Drying Defects, John Wiley & Sons, New York. (1995)

[18] Han SK, Shin DM, Park HY, Jung HW, Hyun JC, Eur. Phys. J. Special Topics, 166, 107 (2009)

[19] Hao Y, Haber S, Int. J. Numer. Meth. Fl., 30, 635 (1999)

[20] Hasegawa T, Sorimachi K, AIChE J., 39, 935 (1993)

[21] Kistler SF, Scriven LE, Int. J. Numer. Meth. Fluids, 4, 207 (1984)

[22] Kistler SF, Schweizer PM, Liquid Film Coating, Chapman & Hall, New York. (1997)

[23] Middleman S, Fundamentals of Polymer Processing, McGraw-Hill, New York. (1977)

[24] Mill CC, South GR, J. Fluid Mech., 28, 523 (1967)

[25] Savage MD, AIChE J., 30, 999 (1984)

[26] Lopez FV, Pauchard L, Rosen M, Rabaud M, J. Non-Newton. Fluid Mech., 103(2-3), 123 (2002)

[27] Weinstein SJ, Ruschak KR, Ann. Rev. Fluid Mech., 36, 29 (2004)

[28] Zevallos GA, Carvalho MS, Pasquali M, J. Non-Newton. Fluid Mech., 130(2-3), 96 (2005)