Coating Process Development and Understanding

1. Coating Process Development
John Glenning
January 15, 2010

2. Coating Process Development
Coating is a complex operation
• Integration of materials, equipment and
processes
• Coating Formulation
• Coating Equipment and Process
• Surface of the film to be coated
• Transportation of the film through the
process
• Drying/Curing of the coating

3. Coating Process Development
Coating Formulation
• Uniform coating formulation within a batch, batch-to-batch & over time

4. Coating Process Development
Coating Formulation
• Uniform coating formulation within a batch, batch-to-batch & over time
• Understand the nature of the coating

5. Coating Process Development
Coating 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 the
forces acting on the fluid (water)

6. Coating Process Development
Coating 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 the
forces acting on the fluid (water)
• Non-Newtonian Fluid: The viscosity of the fluid is dependent on the
forces acting on the fluid (polymers)

7. Coating Process Development
Coating 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 the
forces acting on the fluid (water)
• Non-Newtonian Fluid: The viscosity of the fluid is dependent on the
forces acting on the fluid (polymers)
• Thixotropic: Viscosity decreases with increasing rate of shear
over time (ketchup)
• Pseudoplastic: Viscosity decreases with increasing rate of
shear independent of time (paint)
• Rheopectic: Viscosity increases with increasing rate of shear
over time (pastes)
• Dilatant: Viscosity increases with increasing rate of shear
independent of time (corn starch and water)

8. Coating Process Development
Coating 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 the
forces acting on the fluid (water)
• Non-Newtonian Fluid: The viscosity of the fluid is dependent on the
forces acting on the fluid (polymers)
• Thixotropic: Viscosity decreases with increasing rate of shear
over time (ketchup)
• Pseudoplastic: Viscosity decreases with increasing rate of
shear independent of time (paint)
• Rheopectic: Viscosity increases with increasing rate of shear
over time (pastes)
• Dilatant: Viscosity increases with increasing rate of shear
independent of time (corn starch and water)
• Impact process equipment that manufactures a wide range of products

9. Coating Process Development
Coating Equipment & Process
• Extrusion coating process shears the polymer coating

10. Coating Process Development
Coating 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. Coating Process Development
Coating 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. Coating Process Development
Coating 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. Coating Process Development
Material To Be Coated
• Surface conditions are critical
• Low and uniform surface tension
• Surface tension too high: Delamination
• Uniform surface tension: Uniform coating thicknesses

14. Coating Process Development
Material 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. Coating Process Development
Material 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. Coating Process Development
Material 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. Coating Process Development
Material 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. Coating Process Development
Material Handling
• Material handling is a critical component of coating

19. Coating Process Development
Material Handling
• Material handling is a critical component of coating
• Uniform and proper tension
• Coating Uniformity
• Coating Adhesion

20. Coating Process Development
Material 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. Coating Process Development
Material 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. Coating Process Development
Drying/Curing Oven
• More of an art form than a science

23. Coating Process Development
Drying/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. Coating Process Development
Drying/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. Coating Process Development
End of Presentation