The stretching of paper under the action of liquids means the swelling of the fibers through the receptacle. Paper fibers swell less in the longitudinal direction than in the transverse direction. To obtain comparable measurements, wet elongation is carried out under standard conditions (23 ° C, 50% RH) and with defined counterweights (Fenchel, Mütek CD, Mütek MD).
Wet Expansion Tester
Strain measurement of paper