Development of manufacturing technology of fish block liner for frozen fish packaging (II): Study on bubble coating technology for the manufacturing of domestic fish block liner

Abstract

In a previous study, we found that the deep pores in the coating layers of imported fish block liner have higher Cobb size degrees and lower Gurley air permeability than the domestic prototype block liners and coated linerboards. However, it is impossible to obtain such pores when using the conventional wax coating process; thus, a new coating method is required. In this study, we evaluated a new technique to achieve porous coating layers in coated linerboard. Various mixtures of paraffin wax, low density polyethylene (LDPE), and ethylene vinyl acetate (EVA) were prepared. Then, water spraying was used during conventional coating process to form the pores. The surface of samples coated with and without water spray were analyzed using scanning electron microscopy (SEM). The Cobb size degree and Gurley porosity of coated linerboard were measured in the SEM images to assess the existence of deep pores in the wax coating layer. The 80:15:5 mixture of paraffin wax, LDPE, and EVA reduced the Gurley porosity of coated linerboard. Water spraying was an effective method to obtain porous wax coating layers; better results were observed when using cold water. In addition, a relatively low mixing temperature of the paraffin wax, LDPE, and EVA led to an adequate formation of pores in the wax coating layer. A linerboard with properties similar to those of imported fish block liner was successfully obtained; this material could be used for manufacturing domestic fish block liner. ? 2019 Korean Technical Assoc. of the Pulp and Paper Industry. All rights reserved.