Extrusion Coating Adhesion and Surface Activation
topic
Extrusion coating adhesion to low-surface-energy substrates including polypropylene, polyethylene, and fluoropolymer films requires corona discharge treatment at 40 to 60 watts per square metre per minute, flame treatment, or chemical primer application that increase substrate surface energy above 38 dynes per centimetre before coating, with adhesion adequacy verified by T-peel testing at defined peel rate and temperature confirming bond strength above the minimum specification for the coating application.
Role
Ensures adequate adhesion between extrusion-coated polymer and substrate through surface energy modification that enables the wetting and molecular bonding required for peel-resistant laminate construction, with corona treatment being the most widely used surface activation method for polyolefin substrates where inherently low surface energy prevents adequate adhesion of extrusion-coated polymer without pretreatment that raises surface energy into the range where thermoplastic melt can wet and bond to the substrate.