Bio-Based Dual-Layer UV-Cured Oil- and Water-Resistant Paper Coating for Food Packaging Applications

TL;DR

A sustainable, water- and oil-resistant paper coating was developed using natural materials for food packaging.

Contribution

A novel dual-layer coating using chitosan and acrylated epoxidized soybean oil improves kraft paper's resistance and sustainability.

Findings

The coating achieved a Cobb600 value of 16 g m−2 and a kit rating of 12.

Tensile strength increased from 33 to 40 MPa, and burst strength improved from 260 to 330 kPa.

French fries testing confirmed the coating's barrier performance for food packaging.

Abstract

Fluorine-free paper coatings with water- and oil-resistance properties have gained considerable attention for sustainable food packaging applications. In this study, a dual-layer coating based on chitosan (Chi) and acrylated epoxidized soybean oil (AESO), both derived from renewable and natural resources, was applied to kraft paper. The ultraviolet-cured AESO top layer formed a dense crosslinking network, while the Chi interlayer promoted strong interfacial adhesion with the kraft paper through hydrogen bonding, effectively restricting fluid penetration. The Chi/AESO40/kraft paper showed markedly enhanced water repellency and oil resistance, with a reduced Cobb600 value of 16 g m−2 and kit rating of 12. Thermogravimetric analysis demonstrated improved thermal stability, and mechanical testing results revealed enhanced packaging-relevant strength, with the tensile strength increasing from 33 to 40 MPa and tensile index increasing from 45 to 60 kPa·m2 g−1; furthermore, the burst strength and index improved from 260 to 330 kPa and from 3.2 to 4.0 kPa·m2 g−1, respectively. Food contact tests conducted using French fries confirmed the effective barrier performance of the Chi/AESO/kraft paper, highlighting its potential for use in sustainable paper-based food packaging applications.

Figures