Multi-ply liner for use in corrugated board
The present invention relates to a multi-ply liner for use in corrugated board, said multi-ply liner comprising: a first ply, and a second ply, wherein said first ply comprises at least 70 wt % unbleached kraft pulp and between 5-30 wt % neutral sulfite semi chemical (NSSC) pulp based on dry weight, and wherein said second ply comprises at least 50 wt % NSSC pulp and between 5-50 wt % unbleached kraft pulp based on dry weight.
1 . A multi-ply liner for use in corrugated board, said multi-ply liner comprising:
a first ply, wherein said first ply comprises at least 70 wt % unbleached kraft pulp and between 5-30 wt % neutral sulfite semi chemical (NSSC) pulp based on a dry weight;
a second ply, wherein said second ply comprises at least 50 wt % NSSC pulp and between 5-50 wt % unbleached kraft pulp based on a dry weight; and,
a third ply, wherein said third ply comprises at least 70 wt % unbleached kraft pulp and between 5-30 wt % neutral sulfite semi chemical (NSSC) pulp based on a dry weight,
wherein the multi-ply liner comprises more than 50 wt % neutral sulfite semi chemical (NSSC) pulp based on dry weight, and
wherein the second ply is in between the first ply and the third ply.
2 . The multi-ply liner according to claim 1 , wherein said first ply comprises at least 75 wt % unbleached kraft pulp based on the dry weight.
3 . The multi-ply liner according to claim 1 , wherein said first ply comprises between 5-20 wt % NSSC pulp based on the dry weight.
4 . The multi-ply liner according to claim 1 , wherein said second ply comprises at least 60 wt % NSSC pulp based on the dry weight.
5 . The multi-ply liner according to claim 1 , wherein at least 30% of the second ply comprises recycled cellulose fibers.
6 . The multi-ply liner according to claim 1 , wherein a grammage of each of the first ply and the second ply is in a range of 20-150 g/m 2 .
7 . The multi-ply liner according to claim 1 , wherein an average particle size of the NSSC pulp in the first ply is lower than an average particle size of the NSSC pulp in the second ply.
8 . The multi-ply liner according to claim 1 , wherein said multi-ply liner further comprises an internal sizing agent.
9 . The multi-ply liner according to claim 1 , wherein at least one side of said multi-ply liner has a Cobb 30 s value below 30, as determined according to standard ISO 535.
10 . The multi-ply liner according to claim 1 , wherein said multi-ply liner has an equilibrium moisture content (EMC) of less than 10 wt %, at 50% RH, as determined according to standard ISO 287.
11 . A corrugated board comprising:
the multi-ply liner according to claim 1 , and
a fluting.
12 . A method for manufacturing a multi-ply liner for use in corrugated board, the method comprising the steps of:
a) forming a first web layer from a first pulp suspension and dewatering said first web layer to obtain a first ply;
b) forming a second web layer from a second pulp suspension and dewatering said second web layer to obtain a second ply on the first ply;
wherein said first pulp suspension comprises at least 70 wt % unbleached kraft pulp and between 5-30 wt % neutral sulfite semi chemical (NSSC) pulp based on a dry weight, and
wherein said second pulp suspension comprises at least 50 wt % NSSC pulp and between 5-50 wt % unbleached kraft pulp based on a dry weight;
c) forming a third ply, wherein said third ply comprises at least 70 wt % unbleached kraft pulp and between 5-30 wt % neutral sulfite semi chemical (NSSC) pulp based on a dry weight, wherein the second ply is in between the first ply and the third ply,
wherein the first ply, the second ply, and the third play are dried to form a multi-ply liner comprising at least 50 wt % neutral sulfite semi chemical (NSSC) pulp based on dry weight.