A folding method to increase the rigidity of paperboard tray packages

Abstract

The flange of press-formed paperboard trays was reshaped in this work with a developed folding method to increase the rigidity of the trays. The tray rigidity was evaluated with compression, torsion, and storing tests. The rigidity of the folded trays and the reference trays was compared, and the quality of the trays was investigated with an optical analysis. The folding temperature was altered to 23, 60, and 90 °C to compare the effects of heat input on the tray rigidity. The compression and torsion test results linked the increased tray rigidity to the additional heat input and surface pressure induced to the material in the folding phase. The trays that were folded at 90 °C showed a 43% higher compression force and a 12% smaller torsion angle compared to the reference trays. The storing tests showed an unclear effect on the tray rigidity to the dimensional stability, and the optical analysis depicted similar quality between the folded and the reference trays. The folding method was found to enhance the stacking and end use capabilities of paperboard tray packages, and the use of higher folding temperatures was suggested to increase the strength and stiffness of the trays.