Towards optimized barrier performance using biowaxes and inorganic pigments in coating formulations on fiber-based substrates

Abstract Paper and paperboard materials are among the most common fiber-based packaging materials used for food packaging applications. To stand the moisture, greasiness, and protect the product, fiber-based materials are coated with materials that are often fossil-based plastics. Thus, there is a strong need to find novel sustainable solutions. This study aimed to investigate the effects of natural wax materials on barrier properties when used as coating formulation components in various water-based polymer dispersions on paper board. Specifically, the compatibility of biowaxes with inorganic pigments was studied. Sixteen coating compositions of four biowax materials with two different synthetic polymer dispersions (polyacrylate and polystyrene acrylate) and two different inorganic pigments (talc and calcium carbonate) were prepared in the laboratory scale, and the paperboard sheets were coated using a laboratory rod coater. The barrier properties of the coated sheets were determined and compared to the references (without biowax), and the samples were characterized using scanning electron microscopy (SEM). Based on the results, the use of biowax materials improved water and water vapor resistance. The Cobb 1800 s values decreased by 10 – 40%, and the water vapor transmission rate decreased by 11 – 15% when used with polyacrylate dispersion and talc pigment. Based on the SEM results, these samples also had the smoothest surface at the microscale observed in this study. The results suggest that the barrier properties, especially water and water vapor resistance, of polymer dispersion coating can be optimized based on the use of biowax and pigment components chosen.