Effect of calendering and wetting on paper properties

Fibre coarseness and the fines content of a pulp can have a distinct effect on the combination of sheet properties that are achieved at a certain smoothness level. Low fibre coarseness and the presence of fines from a mechanical pulp seem to give better sheets in terms of optical properties, tensile strength and bending stiffness. Calendering exerts forces on the paper which cause, in addition to a compression of the sheet, rupture of fibre bonds and lateral displacement of fibres and fines particles, which can have an impact on the response of the surface to subsequent treatments. Results suggest that calendering, conditioning, wetting and drying treatments each make its own characteristic impact on the network.