Upscaled Multilayer Dispersion Coating Application for Barrier Packaging: PLAX and bioORMOCER®

Abstract

The shift from fossil-based packaging materials to more sustainable alternatives is driven by evolving environmental regulations aiming for enhanced recyclability and biodegradability. Dispersion coatings, as opposed to extrusion-based approaches, offer significant advantages by reducing the coat weights, but generally, multiple coating layers are needed to meet functional performance requirements. This study explores the application of upscaled multilayer dispersion coatings comprising polylactic acid-based coating (PLAX) and hybrid nanomaterial lacquer (bioORMOCER®) on commercial base papers for barrier packaging using semi-pilot reverse gravure and industrial-scale rod coaters. One multilayer structure demonstrated a low water vapour transmission rate (WVTR), achieving a WVTR of 12 g/(m2·day) under standard conditions and a 78% reduction of WVTR compared to the substrate under elevated humidity. The other multilayer structure exhibited an excellent oxygen transmission rate (OTR) of 2.3 cc/(m2·day·bar) at dry conditions, which is comparable to conventional high-performance alternatives. Both multilayer coatings enhanced the grease and mineral oil barriers significantly, as heptane vapour transmission rate (HVTR) reductions exceeded 97%. The multilayer coatings demonstrated strong potential for scalable production of sustainable, high-barrier packaging materials. These findings highlight the capability of dispersion coatings to replace traditional fossil-based barriers, advancing the development of environmentally friendly packaging solutions.