Full definition
Chemical applied to a substrate before the adhesive to modify surface energy and improve wettability and chemical adhesion. Essential for low-surface-energy plastics (PP: 29 mN/m; PE: 31 mN/m; PTFE: 18 mN/m) that natural adhesives will not wet. Types: organometallic primer, cyanoacrylate activator (Loctite SF 7452), corona or plasma treatment (permanent). Increases joint strength 2–5×.