Assymetric paperboard
AssigneeBillerud Aktiebolag (publ)
InventorsFredrik Nordstrom, Johan Magnusson
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Abstract
There is provided a multi-layered paperboard comprising a first outer layer, a second outer layer and at least one middle layer arranged between the first and the second outer layer, wherein the grammage of the first outer layer is at least 2.0 times higher than the grammage of the second outer layer. A method of producing the multi-layered paperboard is also provided.
Claims17
A multi-layered paperboard comprising a first outer layer, a second outer layer and at least one middle layer arranged between the first and the second outer layer, wherein all these layers are based on cellulose fibers and wherein the grammage of the first outer layer is at least 2.0 times higher than the grammage of the second outer layer, the grammage of the second outer layer is below 25 g/m2 and the density of the at least one middle layer is lower than the density of the first outer layer and the density of the second outer layer.
A method of forming, in a full-scale paperboard machine, a multi-layered paperboard comprising a first outer layer, a second outer layer and at least one middle layer arranged between the first and the second outer layer, said method comprising the steps of:
- forming the first outer layer from a first furnish;
- forming the second outer layer from a second furnish;
- and
- forming said at least one middle layer from at least one middle layer furnish,
- wherein the flows and consistencies of the first and the second furnish are such that the grammage of the first outer layer is at least 2.0 times higher than the grammage of the second outer layer, the flow and consistency of the second furnish are such that the grammage of the second outer layer is below 25 g/m2 and the density of the at least one middle layer is lower than the density of the first outer layer and the density of the second outer layer.
Dependencies are inferred from the claim text.