Assymetric Paperboard
AssigneeBillerud Aktiebolag (publ)
InventorsFredrik Nordstrom, Johan Magnusson
Life of this patent
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Abstract
There is provided a multi-layered paperboard (200, 300) comprising a first cellulose fibre-based layer (201, 301) and a second cellulose fibre-based layer (202, 302), which second layer (202, 302) has an inner surface facing in the direction of the first layer (201, 301) and an outer surface facing in the opposite direction, wherein the density of the second layer (202, 302) is below 550 kg/m3 and lower than the density of the first layer (201, 301) and wherein an additive (204, 304) selected from the group consisting of starch, fines, MFC, CMC and PVOH is added to the outer surface of the second layer (202, 302), with the proviso that no further cellulose fibre-based layer is provided on the outer surface of the second layer (202, 302).
Claims18
A multi-layered paperboard (200, 300) comprising:
- a first cellulose fiber-based layer (201, 301) and a second cellulose fiber-based layer (202, 302), which second layer (202, 302) has an inner surface facing in the direction of the first layer (201, 301) and an outer surface facing in the opposite direction,
- wherein the density of the second layer (202, 302) is below 550 kg/m3 and lower than the density of the first layer (201, 301) and
- wherein an additive (204, 304) selected from the group consisting of starch, fines, MFC, CMC and PVOH is added to the outer surface of the second layer (202, 302),
- with the proviso that no further cellulose fiber-based layer is provided on the outer surface of the second layer (202, 302).
A method of forming, in a full-scale paperboard machine, a multi-layered paperboard (200, 300) comprising a first cellulose fiber-based layer (201, 301) and a second cellulose fiber-based layer (202, 302), wherein the density of the second layer (202, 302) is below 550 kg/m3 and lower than the density of the first layer (201, 301), said method comprising the steps of:
- forming a first fiber web from a first furnish;
- forming a second fiber web from a second furnish;
- adding an additive (204, 304) selected from the group consisting of starch, fines, MFC, CMC and PVOH to a side of the second fiber web that is not merged with another fiber web in the full-scale paperboard machine.
Dependencies are inferred from the claim text.