Polyolefins are widely employed as external skins for flexible packaging, yet their nonpolar, hydrophobic surfaces present challenges for high-resolution, wear-resistant printing. Converters have traditionally relied on surface treatments, such as corona treatment, to increase surface free energy (SFE) and promote compatibility with solvent-based inks. While water-based inks offer sustainability advantages and reduced volatile organic compound exposure over solvent-based inks, their adhesion to polymer substrates is inconsistent and generally not robust. Industry guidelines suggest SFE differentials between ink and substrate are the only factor influencing adhesion; however, this factor may not completely describe the ink-substrate interactions. The adhesion performance of water-based inks was evaluated on polyethylene, ethylene acrylic acid copolymer, ethylene vinyl alcohol copolymer, and polyamide. Polymer films were examined pre- and post-corona treatment to assess changes in surface energy, chemistry, and topography on ink printability and durability. To achieve acceptable print durability, these polymers all required corona treatment, leading to chemical and morphological modifications to the film surface. Results demonstrated that surface chemistry and topography are stronger indicators of water-based ink adhesion than SFE alone. These findings establish a framework for optimizing the durability of water-based inks on polyolefins and related substrates through targeted surface treatment strategies.

Corona treatment is an essential process used in the flexible packaging industry to improve adhesion on low surface-energy polymers. This paper explores how corona treatment prepares polymers for adhesion, how surface energy correlates to a good bond, forms of measurement and common pitfalls to avoid. By understanding the function of corona treatment and the science of the bond, converters can achieve consistent adhesion in printing, coating and laminating applications.

Plasticizer migration from plastics, particularly in polar polymers like flexible PVC, poses significant health risks, including endocrine disruption and carcinogenicity. This review article consolidates research on surface modification techniques aimed at suppressing plasticizer migration, which are crucial for minimizing health and environmental hazards. Over the past decade, substantial advancements have been made in this field. Physical irradiation methods, including plasma, ultraviolet, and gamma-ray irradiation—induce surface cross-linking, forming a three-dimensional network that reduces plasticizer migration by up to 80 %, as demonstrated by DEHP loss decreasing from 5.6 to 1.2 mg/cm2 in modified PVC. Chemical grafting techniques covalently attach hydrophilic groups or polymer chains, which interact with plasticizers via hydrogen bonding and van der Waals forces, achieving a 75 % reduction in migration, for example, DEHP leaching from 250 mg to 52 mg. Solution coating methods, particularly protein-based coatings, show exceptional performance with up to 93 % inhibition, reducing DEHP migration from 60 ppm to 4.2 ppm. Despite these achievements, challenges persist in enhancing coating durability, reducing costs, and minimizing environmental risks. Future research directions should focus on improving the long-term stability of coatings, refining experimental methodologies, and establishing robust evaluation standards. This work aims to provide a critical reference for the development of safer plastic applications in healthcare and food packaging industries, offering insights into the design and implementation of effective surface modification strategies to address the ongoing issue of plasticizer migration in plastic materials.