Effect of Drying Method on the Creep Behaviour of Paper

As new drying processes develop, it is pertinent to ask if they might also alleviate problems related to creep and stress relaxation. To examine this, we compared cylinder drying, impingement drying and the standard handsheet drying. We used three furnishes having different proportions of cellulose, hemicellulose and lignin. For the measurement of tensile creep strain, we used non-contact video image correlation technique, in which the strain was measured from digitised specimen images taken by CCD camera. We introduced creep number to simplify the description of creep behaviour. We found that the drying methods did not make any significant difference in affecting the creep response (indicated by the creep number) of normal handsheets (made from PS-AQ pulp or high yield pulp). We also discussed the possibility to predict the creep response in long time scale.