New water-based barrier coatings for paper and paperboard

Results obtained with new water-based barrier coatings for paper and paperb oard are presented. These coatings include polyester-based coatings, disper sions containing hydrophobic monomers and coatings made from biodegradable polymers. Coatings were tested as such, some were filled with talc and some were used as an additive in a commercial polymer dispersion. Relatively go od barrier values were achieved. However, work needs to be done to optimise the properties of biodegradable polymers for waterbased coatings. The object of this study was also to compare different fillers and additive s in water-based barrier coatings. The coating performance can be controlle d by a suitable choice of fillers. Folding of filled coatings destroys the barrier due to pinholes and cracks. Certain additives can improve the barri er performance of the coatings; however, filler type and filler addition le vel are often the dominating factors as far as barrier properties are conce rned.