Contact Angle Goniometry Protocols for Polyolefin Lamination Adhesion Verification
Sessile contact angle goniometry isolates polar and dispersive surface energy to verify polyolefin corona treatment and prevent lamination delamination.
Slip Migration
Additive Movement
Formulated plastic coatings often contain processing aids that alter the friction characteristics of the finished material. Through slip migration, amide waxes dissolved in the molten polymer move to the surface as the coating cools and ages. This process creates a thin, lubricating layer that reduces the coefficient of friction of the plastic surface.
It is essential for ensuring that plastic-coated paperboards feed smoothly through packaging machines and folder-gluers.
Coefficient Shift
Freshly coated rolls can exhibit high friction which makes them difficult to unwind and convert. As slip migration occurs over twenty-four to forty-eight hours, the coefficient of friction drops to a stable target range. This delay in performance shift requires converters to store rolls for a specific seasoning period before processing them.
Adhesion Problems
Excessive amounts of wax on the surface of the polymer can interfere with downstream converting steps. If slip migration is too intense, the accumulated lubricating layer prevents printing inks and hot-melt adhesives from bonding to the board. Packaging labs test for this condition by measuring both surface tension and heat-seal strength over time.
This monitoring helps chemical suppliers adjust the slip additive concentration to find the right balance between glide and stick.