Effect of Humidity on Paper and Corrugated Board Strength Parameters

Abstract

One of the main problems as regards practical utilisation of corrugated board as packaging material is reduced strength followed by the higher humidity of the fibrous materials of which corrugated board is made. Based on the results of laboratory tests, the effect of humidity on the Young’s modulus, Poison’s ratio and strength properties of fibrous materials used for corrugated and coating layers as well as on the bending stiffness and edge crush strength of corrugated board were determined. Treating fibrous materials as elastic bodies, the stiffness and edge crush strength of the board tested were calculated theoretically. A comparison between calculation and measurement results proved that it is possible to predict changes in the mechanical properties of corrugated board caused by changes in humidity provided we know the effect of humidity on basic properties of the fibrous material of which the corrugated board was made.