How Printability of Polyethylene Packaging Films Containing Surface Additives Is Influenced by Corona Treatment

ABSTRACT Corona treatment is widely performed to enhance the printability of polyethylene packaging films. This study investigates the interplay between corona treatment and surface additives in order to modify short‐term and long‐term surface characteristics. Samples were produced via blown film extrusion and evaluated in terms of surface energy, coefficient of friction (COF), blocking force, haze, surface crystallinity (GI‐XRD), surface morphology (AFM), and ink adhesion over a 1‐year period. Treatment increased the surface energy up to 40 mJ/m 2 immediately after film production. In samples with high additive content, surface energy declined to less than 36 mJ/m 2 within a 2‐week period due to additive migration. Films containing moderate levels of a fatty acid amide slip‐agent, combined with a proper concentration of inorganic anti‐blocks, demonstrated a well‐balanced performance maintaining both the COF values below 0.3 and blocking force to be ca. 4–5 N. This led to having 85% of total possible printability of ink to films even after 1 year of aging. Also, high surface crystallinity (> 40%), as confirmed by GI‐XRD, was seen to correlate well with improved ink adhesion.