Paper or paperboard laminate having at least one bulk layer and at least one secondary layer where the cellulose fibres of the bulk layer have a freeness value of 550 to 950 ml CSF

摘要

Paper or paperboard laminate composed of at least one bulk-promoting layer, here termed the bulk layer, and on at least one side of the bulk layer at least one secondary layer, secondary layer and bulk layer being joined to one another directly or indirectly over basically the whole of their surfaces facing one another. 40-95 % of the bulk layer consists of cellulose fibres with a freeness of 550-950 ml CSF, the secondary layer/layers has/have a greater density than the bulk layer, and the laminate has a bending stiffness index higher than 2.5 Nm<7>/kg<3>, but less than 14 Nm<7>/kg<3>, calculated as a geometric mean value for machine and transverse direction. The invention also relates to a method of producing said paper or paperboard laminate.