Process Induced Curl in Paperboard,-Exploratory Experiments on Drying Strategies and Possible Curl Controlling Mechanisms, 2002 Technology Summit Proceedings
M. Persson & T. Wahlström
In laboratory investigations, curl has mainly been studied by exposing already dried and conditioned paperboard to changes in the ambient climate. This information is used to predict how the paperboard behaves in a converting operation. The papermaker, however, also needs to know how to make changes in his process to obtain the desired curl before converting: the process-induced curl.
In an exploratory study, a laboratory drier was used to investigate the influence of different drying strategies on curl. By changing the amount of drying from each side of the paperboard it was possible to control the curl. To find potential mechanisms that influence the curl response, four complementary trials were made. The evaporation, free shrinkage, moisture gradients, and conditioning were investigated. The results indicate that the specific development of moisture gradients during drying influences the final curl response.
Process Induced Curl in Paperboard,-Exploratory Experiments on Drying Strategies and Possible Curl C
