Patent ID: 11926128
Assignee: STORA ENSO OYJ
Field: Textile and paper machines (Mechanical engineering)
Classification: CPC B  D | IPC B  D

Claim 0:
1. A corrugated board comprising:
a corrugated medium, and
a linerboard, wherein the linerboard has a grammage between 80 to 150 gsm and wherein the linerboard comprises:
a first ply, wherein said first ply comprises 20-80 wt % CTMP from wood fibers and 80-20 wt % chemical pulp, all percentages calculated on a total fiber weight of said first ply, and
wherein the CTMP exhibits a bulk according to ISO 534:2005 of at least 2.5 cm3/g,
wherein the CTMP has a freeness according to ISO 5267-2 of at least 300 ml, and,
wherein said first ply has a density according to ISO 534 of below 690 kg/m3,
a second ply, wherein the second ply comprises 100 wt % kraft pulp calculated on a total fiber weight of said second ply,
a third ply, wherein the third ply comprises 30-70 wt % CTMP and 30-70 wt % kraft pulp calculated on a total fiber weight of said third ply, and
wherein said second ply forms a top ply, said first ply forms a middle ply, and said third ply forms a back ply.