Comparison between Forming Strategies Regarding Their Effect on Paper Properties

摘要

Extensive trials have been performed at the FEX machine at Innventia in Stockholm in order to determine fundamental relations between several process parameters. The goal with these has been to set up a matrix for further research aimed at the formation-retention-strength relations. The trials covered a total of five weeks at the FEX machine. Three of those were aimed at twin-wire forming and two at Fourdrinier forming. The results from these five weeks clearly show the difference between twin-wire and Fourdrinier forming. For the Fourdrinier case there is a linear relation between small-scale (0.3-3 mm) formation and large-scale (3-30 mm) formation, a higher value for the small-scale formation also gives a higher large-scale value. Furthermore, there is a direct relation between formation and retention; an increased retention gives a higher formation value. In addition, it is shown that a better formation gives a higher tensile index value. In comparison, it is shown that twin-wire forming does not have these clear relations. Hence, the twin-wire forming process seems to allow de-coupling of many of these relations.