Creasing characteristic of aluminum foil coated paperboard

In this paper, to clarify a rule indentation effect on failure occurrence in the surface layer of paperboard, an aluminum foil coated paperboard was experimentally scored and folded by using a couple of creasing rules and square groove plates. The specimen was made with a 15 μm thickness aluminum foil and a 360 g/m2 high quality white-coated paperboard by using adhesive glue spray. The state of creased part was observed with a CCD microscope and the relationship between the bending momentum resistance and the bending angle was compared with that of the normal paperboard. The relationship between the indentation depth of creasing rule and the in-plane stretching strain in the surface layer was investigated by using a new measurement method, and the occurrence limit of surface failure of aluminum foil was discussed with the tensile strength of the material. Through this work, it was confirmed that the in-plane stretching strain in the surface layer has affected the failure limit of aluminum foil layer of the specimen. It was also concluded that the proposed method of strain measurement on the bent surface layer was enable to discuss the failure strength of surface layer.