Stora Enso Oyj

Atso Laakso

Seppo Lampainen

Frank Peng

Ari-Pekka Määttänen

Kaj Backfolk

Janne Myllykangas

Petri Paakkanen

The invention relates to a method to produce a linerboard exhibiting a high bending resistance and a high compression strength, which in turn provides high resistance to interflute buckling and sagging in a thereof formed corrugated board. This is achieved by the inventive combination of an optimized fiber refining level of the furnish in each layer of the linerboard, the separate formation of the top layer and the use of a multi-layer headbox to form the two-layered ply. In addition, the linerboard made according to the invention provides good printing properties in a thereof produced corrugated board, especially in flexographic printing, without the fluting structure being negatively affected.

Light weight linerboard for corrugated board

The invention relates to a ply of a linerboard for corrugated board, which ply exhibits high strength properties and which enables the production of lightweight linerboards. The ply of the invention comprises 20-80 wt % CTMP from wood fibers and 80-20 wt % chemical pulp, calculated on the total fiber weight of said ply and strength additives chosen from the group of microfibrillated cellulose (MFC), anionic or cationic polymers and starch or combinations thereof. The ply exhibits a geometric SCT index of above 22 Nm/g and a density of below 680 kg/m, preferably of below 650 kg/m.

Ply of a linerboard and a light weight linerboard for corrugated board

The invention relates to a lightweight linerboard for corrugated board with good strength properties and which reduces problems with washboarding in the thereof produced corrugated board. The linerboard of the invention comprises at least one ply comprising 20-80 wt % CTMP from wood fibers and 20-80 wt % chemical pulp, all percentages calculated on the total fiber weight of said first ply, wherein the CTMP exhibits a bulk of at least 2.5 cm/g.

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Varkaus, Finland

Atso Laakso