包装油墨 化学品

Solventborne nitrocellulose/polyurethane inks dominate flexible packaging gravure and flexo printing. They offer fast drying, excellent adhesion to OPP, PET, and BOPP films, and good lamination bond strength. Waterborne inks are growing for sustainability reasons but require careful substrate treatment. UV-curable inks are used in label printing for energy efficiency and instant cure.

Low-migration ink formulations use large-molecule photoinitiators (for UV systems), polymeric binders with low diffusivity, and restricted substance lists compliant with Swiss Ordinance 817.023.21 and EuPIA guidelines. Migration testing per EN 1186 or OML/SML testing under food simulant conditions is required. Ink suppliers provide migration test data for compliance verification.

After printing, flexible packaging films are typically laminated to a sealant layer with polyurethane or solvent-free adhesives. The ink layer sits in the laminate bond line and must not cause delamination. Adhesion promoters, properly cured binders, and residual solvent control (< 5 mg/m²) are critical. Polyurethane-based inks form chemical bonds with PU laminating adhesives for superior bond strength.