Biowaxes Used as a Barrier Formulation Material in Coating Fibre‐Based Substrates

Abstract

Recently, replacing plastic packaging materials with biobased alternatives has been trending in the field of food packaging. The role of food packaging materials is to contain and protect the product throughout the supply chain, and the most used materials for this are polyolefins due to their functionality and affordability. However, environmental awareness and the new regulations and restrictions have been strong drivers to push the development towards biobased materials. In this study, the feasibility and potential of biowaxes used as a dispersion barrier coating formulation material were examined. Four commercial biowaxes were selected for the study, and their nano‐ and crystalline structures were determined by wide‐angle X‐ray scattering (WAXS). The biowaxes were melted and dispersed into a stable water‐based dispersion. Barrier coating formulations were prepared using two different polymer dispersions mixed with the waxes and additives. A fibre substrate was coated with the prepared formulations, and their barrier properties were studied. The properties of biowax‐containing coatings showed similar or minor improvements compared to the reference. However, foldability was especially improved in the biowax sample. Interestingly, this sample contained wax, which was structurally most stable, presenting an orthorhombic phase in all studied states. Based on our results, introducing biowax materials is a viable solution to replace part of the formulation materials and adjust the barrier performance of existing dispersion polymers. Our results also suggest that the nanostructure of waxes might play a role in an optimal solution. However, all these observations deserve more studies, and the share of biowax in barrier coatings will need further optimisation in the future.