Ring rush creep

A new experimental rig, to perform ring crush creep testing under changing environmental conditions, has been built and is described. For the first ti me the viscoelastic compressive creep properties of paper in a ring crush c onfiguration are measured and the results presented. Ring crush is a widely used measure of the edgewise compression performance of linerboard; Even though the ring crush test is believed to be replicati ng the buckling type failure mechanism of the liner in a box wall (12), the test is a short duration strength test as opposed to a long-term viscoelas tic creep effect seen in the product. If the failure of a box wall due to a ccelerated creep is also buckling dominated then the creep testing of a rin g crush sample could offer valuable insight into the behaviour. Handsheets have been made at 160g/m(2) from randomised stocks of E. globulu s NSSC pulp on a Moving Belt Drainage Former (MBDF). The pulp was beaten to various freeness levels and the sheets were exposed to various levels of w et pressing. The effects of beating and pressing on ring crush creep are pr esented and a comparison made between ring crush and tensile Creep behavior .