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.

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.

The present invention includes pleated paper and planar paper coated with a fire suppressive ink, wherein the pleated paper is Kraft paper with a weight of 25 to 50 pounds, with pleat angles of about 88 to 92°, and pleat heights between approximately 3/32 of an inch and ⅛ of an inch, and the planar paper is Kraft paper with a weight of 40 to 60 pounds. The fire suppressive ink is preferably applied with a flexographic printing process and preferably comprises at least one inorganic fusible salt and an organic resin. The inventive pleated paper is an environmentally friendly packaging material with improved protective qualities, which can also shield items from fire, contain fires, and suppress fires to avoid thermal runaway. The inventive paper is particularly useful for packaging and shipping flammable items, such as lithium-ion batteries.

The present invention includes pleated paper and planar paper coated with a fire suppressive ink, wherein the pleated paper is Kraft paper with a weight of 25 to 50 pounds, with pleat angles of about 88 to 92°, and pleat heights between approximately 3/32 of an inch and ⅛ of an inch, and the planar paper is Kraft paper with a weight of 40 to 60 pounds. The fire suppressive ink is preferably applied with a flexographic printing process and preferably comprises at least one inorganic fusible salt and an organic resin. The inventive pleated paper is an environmentally friendly packaging material with improved protective qualities, which can also shield items from fire, contain fires, and suppress fires to avoid thermal runaway. The inventive paper is particularly useful for packaging and shipping flammable items, such as lithium-ion batteries.

In manufacturing two-sided laminated cardboard (1) in a laminating apparatus (10), by controlling band tensions of a first outer layer (11) and a second outer layer (12), a torque difference between an exerted first torque (Q1) in an upper roller (21) and an exerted second torque (Q2) in a lower roller (22) is controlled towards a pre-determined value (ΔQ) of said torque difference, while at the same time a torque addition sum of the first torque and the second torque is controlled towards a pre-determined constant value (Q) of said torque addition sum. Thus the invention provides an effective and reliable solution for counteracting concaveness or convexness, in the conveying direction (MD), of the two-sided laminated cardboard (1) to be manufactured.

In manufacturing two-sided laminated cardboard (1) in a laminating apparatus (10), by controlling band tensions of a first outer layer (11) and a second outer layer (12), a torque difference between an exerted first torque (Q1) in an upper roller (21) and an exerted second torque (Q2) in a lower roller (22) is controlled towards a pre-determined value (ΔQ) of said torque difference, while at the same time a torque addition sum of the first torque and the second torque is controlled towards a pre-determined constant value (Q) of said torque addition sum. Thus the invention provides an effective and reliable solution for counteracting concaveness or convexness, in the conveying direction (MD), of the two-sided laminated cardboard (1) to be manufactured.

A method for producing a paperboard comprising the steps of; providing a furnish comprising cellulosic fibers, applying the furnish on at least one wire to form a web, dewatering the web on said at least one wire by subjecting the web to a pressure above 150 kPa without the use of a press roll nip and thereafter pressing the dewatered web to form a paperboard. Also a paperboard and a corrugated board produced by such a process.

A method for producing a paperboard comprising the steps of; providing a furnish comprising cellulosic fibers, applying the furnish on at least one wire to form a web, dewatering the web on said at least one wire by subjecting the web to a pressure above 150 kPa without the use of a press roll nip and thereafter pressing the dewatered web to form a paperboard. Also a paperboard and a corrugated board produced by such a process.

A corrugated cardboard includes a first cellulosic fibered linerboard layer treated with a wet strength agent, a second cellulosic fibered linerboard layer, and a non-wicking corrugating medium attached to and disposed between the first cellulosic fibered linerboard layer and the second cellulosic fibered linerboard layer.

A corrugated cardboard includes a first cellulosic fibered linerboard layer treated with a wet strength agent, a second cellulosic fibered linerboard layer, and a non-wicking corrugating medium attached to and disposed between the first cellulosic fibered linerboard layer and the second cellulosic fibered linerboard layer.