Method for production of a multi-ply paperboard

Abstract

The present disclosure provides a method for making a multi-ply paperboard, wherein the method comprises the following steps: a) forming a first web from a first furnish comprising fibres on a first forming wire wherein the first furnish is applied on the first forming wire using a first jet speed at a first jet-to-wire speed difference, wherein the first jet-to-wire speed difference is in the range of: +15 to +30 m/min, such as +16 to +25 m/min; or −15 to −30 m/min, such as −16 to −25 m/min; b) forming a second web from a second furnish comprising fibres on a second forming wire using a second jet speed, wherein the second jet speed is closer to the speed of the second forming wire than the first jet speed to the speed of the first forming wire; c) forming a third web from a third furnish comprising fibres on a third forming wire using a third jet speed, wherein the third jet speed is closer to the speed of the third forming wire than the first jet speed to the speed of the first forming wire; d) causing the second web to oscillate in a direction transverse to the machine direction (MD), wherein the stroke length in the oscillation of the second web is 10-35 mm; and e) combining the first, second and third webs into the multi-ply paperboard, wherein the first web forms a top-ply, the second web forms a middle ply and the third web forms a back-ply in the multi-ply paperboard.

Dependencies are inferred from the claim text.