Types of Primers Used in the Printing Industry: From Functional Mechanisms to Application-Oriented Objectives

Primers, as functional interfacial layers, play a crucial role in enhancing print quality, improving ink adhesion, and boosting the durability of printed layers. Amid the expanding variety of printing substrates—from cellulosic materials and metallic foils to polymeric films—designing primers tailored to substrate properties and printing technologies has grown essential. This review elucidates primers' functional mechanisms, emphasizing that modifying surface characteristics like energy, wettability, roughness, and uniformity is prerequisite for high-resolution printing and long-term stability. Systematically analyzing their physical and chemical roles, primers enhance surface energy and reduce ink contact angles, form chemical bonds and intermolecular interactions, promote mechanical interlocking, and control ink absorption/penetration—key to superior adhesion and visual quality. Studies reveal primers not only optimize ink transfer and fixation but also elevate process efficiency via surface leveling and ink drying/curing regulation. Primer types—solvent-based, water-based, radiation-curable, and nanoparticle-based—are comparatively evaluated. Appropriate primer selection demands deep insight into primer-ink-substrate interactions and processing conditions. Recent trends focus on sustainable, multifunctional primers for digital and industrial inkjet printing. The future envisions smart, bio-based, recyclable systems meeting technical, economic, and environmental demands.