Coating processes

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Coating Process Development and Understanding

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Coating processes

  1. 1. Coating Process DevelopmentJohn GlenningJanuary 15, 2010
  2. 2. Coating Process DevelopmentCoating is a complex operation• Integration of materials, equipment andprocesses• Coating Formulation• Coating Equipment and Process• Surface of the film to be coated• Transportation of the film through theprocess• Drying/Curing of the coating
  3. 3. Coating Process DevelopmentCoating Formulation• Uniform coating formulation within a batch, batch-to-batch & over time
  4. 4. Coating Process DevelopmentCoating Formulation• Uniform coating formulation within a batch, batch-to-batch & over time• Understand the nature of the coating
  5. 5. Coating Process DevelopmentCoating Formulation• Uniform coating formulation within a batch, batch-to-batch & over time• Understand the nature of the coating• Newtonian Fluid: The viscosity of the fluid is independent on theforces acting on the fluid (water)
  6. 6. Coating Process DevelopmentCoating Formulation• Uniform coating formulation within a batch, batch-to-batch & over time• Understand the nature of the coating• Newtonian Fluid: The viscosity of the fluid is independent on theforces acting on the fluid (water)• Non-Newtonian Fluid: The viscosity of the fluid is dependent on theforces acting on the fluid (polymers)
  7. 7. Coating Process DevelopmentCoating Formulation• Uniform coating formulation within a batch, batch-to-batch & over time• Understand the nature of the coating• Newtonian Fluid: The viscosity of the fluid is independent on theforces acting on the fluid (water)• Non-Newtonian Fluid: The viscosity of the fluid is dependent on theforces acting on the fluid (polymers)• Thixotropic: Viscosity decreases with increasing rate of shearover time (ketchup)• Pseudoplastic: Viscosity decreases with increasing rate ofshear independent of time (paint)• Rheopectic: Viscosity increases with increasing rate of shearover time (pastes)• Dilatant: Viscosity increases with increasing rate of shearindependent of time (corn starch and water)
  8. 8. Coating Process DevelopmentCoating Formulation• Uniform coating formulation within a batch, batch-to-batch & over time• Understand the nature of the coating• Newtonian Fluid: The viscosity of the fluid is independent on theforces acting on the fluid (water)• Non-Newtonian Fluid: The viscosity of the fluid is dependent on theforces acting on the fluid (polymers)• Thixotropic: Viscosity decreases with increasing rate of shearover time (ketchup)• Pseudoplastic: Viscosity decreases with increasing rate ofshear independent of time (paint)• Rheopectic: Viscosity increases with increasing rate of shearover time (pastes)• Dilatant: Viscosity increases with increasing rate of shearindependent of time (corn starch and water)• Impact process equipment that manufactures a wide range of products
  9. 9. Coating Process DevelopmentCoating Equipment & Process• Extrusion coating process shears the polymer coating
  10. 10. Coating Process DevelopmentCoating Equipment & Process• Extrusion coating process shears the polymer coating• Shearing applies stresses to the coating material• Coating performance depends on the type of coating
  11. 11. Coating Process DevelopmentCoating Equipment & Process• Extrusion coating process shears the polymer coating• Shearing applies stresses to the coating material• Coating performance depends on the type of coating• Control the coating process and equipment• Uniform & proper gap in space and time• Uniform & proper vacuum in space and time• Uniform & proper flow rate in space and time• Uniform & proper coating temperature in space and time• Uniform & proper solids concentration in space and time
  12. 12. Coating Process DevelopmentCoating Equipment & Process• Extrusion coating process shears the polymer coating• Shearing applies stresses to the coating material• Coating performance depends on the type of coating• Control the coating process and equipment• Uniform & proper gap in space and time• Uniform & proper vacuum in space and time• Uniform & proper flow rate in space and time• Uniform & proper coating temperature in space and time• Uniform & proper solids concentration in space and time• Season change impacts coating processes
  13. 13. Coating Process DevelopmentMaterial To Be Coated• Surface conditions are critical• Low and uniform surface tension• Surface tension too high: Delamination• Uniform surface tension: Uniform coating thicknesses
  14. 14. Coating Process DevelopmentMaterial To Be Coated• Surface conditions are critical• Low and uniform surface tension• Surface tension too high: Delamination• Uniform surface tension: Uniform coating thicknesses• Prepare the surface: Cannot “over clean” or “over dry”• Remove oils• Remove debris• Remove oxides• Dry the surface• How fast do oxides reform
  15. 15. Coating Process DevelopmentMaterial To Be Coated• Surface conditions are critical• Low and uniform surface tension• Surface tension too high: Delamination• Uniform surface tension: Uniform coating thicknesses• Prepare the surface: Cannot “over clean” or “over dry”• Remove oils• Remove debris• Remove oxides• Dry the surface• How fast do oxides reform• Coat immediately after the surface is dried
  16. 16. Coating Process DevelopmentMaterial To Be Coated• Surface conditions are critical• Low and uniform surface tension• Surface tension too high: Delamination• Uniform surface tension: Uniform coating thicknesses• Prepare the surface: Cannot “over clean” or “over dry”• Remove oils• Remove debris• Remove oxides• Dry the surface• How fast do oxides reform• Coat immediately after the surface is dried• Does the material being coated out-gasses: Delamination
  17. 17. Coating Process DevelopmentMaterial To Be Coated• Surface conditions are critical• Low and uniform surface tension• Surface tension too high: Delamination• Uniform surface tension: Uniform coating thicknesses• Prepare the surface: Cannot “over clean” or “over dry”• Remove oils• Remove debris• Remove oxides• Dry the surface• How fast do oxides reform• Coat immediately after the surface is dried• Does the material being coated out-gasses: Delamination• Microetch the surface-Increasing the surface area
  18. 18. Coating Process DevelopmentMaterial Handling• Material handling is a critical component of coating
  19. 19. Coating Process DevelopmentMaterial Handling• Material handling is a critical component of coating• Uniform and proper tension• Coating Uniformity• Coating Adhesion
  20. 20. Coating Process DevelopmentMaterial Handling• Material handling is a critical component of coating• Uniform and proper tension• Coating Uniformity• Coating Adhesion• Uniform and proper line speed• Coating Thickness• Coating Uniformity
  21. 21. Coating Process DevelopmentMaterial Handling• Material handling is a critical component of coating• Uniform and proper tension• Coating Uniformity• Coating Adhesion• Uniform and proper line speed• Coating Thickness• Coating Uniformity• Good Viscosity and temperature control of the coating• Uniform and proper tracking• Coating Thickness• Coating Uniformity• Coating Adhesion
  22. 22. Coating Process DevelopmentDrying/Curing Oven• More of an art form than a science
  23. 23. Coating Process DevelopmentDrying/Curing Oven• More of an art form than a science• Surface “skinning”• Trap solvents• Slow down drying• Surface damage due to “blistering”• Heat from the bottom up
  24. 24. Coating Process DevelopmentDrying/Curing Oven• More of an art form than a science• Surface “skinning”• Trap solvents• Slow down drying• Surface damage due to “blistering”• Heat from the bottom up• Air Flow• Coating damage due to air flow: Turbulent Flow• Break-up the boundary layer: Laminar flow• Rapid air exchange in the oven• No eddy currents in the oven• Counter-current air flow
  25. 25. Coating Process DevelopmentEnd of Presentation

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