EP4214358A1

EP4214358A1 - Pallet outer packaging paper

Info

Publication number: EP4214358A1
Application number: EP21794706.8A
Authority: EP
Inventors: Lars Göran Berglund; Elisabeth SCHWAIGER
Original assignee: Mondi AG
Current assignee: Mondi AG
Priority date: 2020-09-16
Filing date: 2021-09-15
Publication date: 2023-07-26
Also published as: SE2350395A1; AU2021345372A1; SK500162023A3; FI130579B; ES2900308B2; GB2613511A; SE545997C2; FI20235325A1; CN116157574A; AT524260A1; WO2022056567A1; CZ2023107A3; CA3195677A1; MX2023003187A; DE112021004848A5; AT524260B1; ES2900308A1; PL444257A1; GB202303694D0; BR112023004858A2

Abstract

The invention relates to pallet outer packaging paper, to an outer packaging method using this pallet outer packaging paper as an outer packaging material, and to a method for producing such pallet outer packaging paper. The pallet outer packaging paper comprises at least 70 wt.% cellulose fibres having a length-weighted average fibre length in accordance with ISO 16065-2:2014 of 1.8 mm to 2.8 mm, and has a bending stiffness in accordance with ISO 2493-1:2010, using a bend angle of 15° and a test bend length of 10 mm, of at most 35 mN in the machine direction and at most 30 mN in the transverse direction, and a bending stiffness index of at most 100 Nm6/kg3 in the machine direction and at most 80 Nm6/kg3 in the transverse direction, and a grammage of 50g/m2 to 90 g/m2.

Description

PALLET WRAPPING PAPER

The invention relates to a pallet wrapping paper, in particular for wrapping homogeneous pallets, a wrapping method for pallets using such a pallet wrapping paper and a method for producing such a pallet wrapping paper.

In the attempt to significantly reduce the amount of plastic or plastic materials in principle, suitable substitute materials for plastic are being sought in many areas. For example, replacement solutions for the plastic films that are ubiquitous in the packaging industry are being sought. Due to the inherent properties of plastic films, such as good deformability and stretchability combined with good strength, the replacement of plastic films by materials with comparable properties has not yet been fully successful in many areas.

Paper has been proposed as an alternative to plastic films in many areas. In addition to other alternative materials, paper has already been mentioned in the past as an alternative for the present case of pallet outer packaging. For example, EP 0 533 520 B1, JP H05310211 A, FR 2675466 A1 or DE 40 18111 A1 deal with the packaging of pallets, with these documents basically naming paper as the packaging material. However, hardly any more detailed information regarding paper qualities with suitable properties can be found in the documents mentioned and also in the further prior art on pallet outer packaging. Paper is usually only mentioned as a possible outer packaging material and is not described in detail. However, obviously not every paper is also suitable as an outer packaging material for securing pallets.

A prerequisite for possible use as a pallet outer packaging material is good deformability, including stretchability, since the outer packaging material usually has to be wrapped completely around a pallet under pretension. In principle, special papers with good extensibility are already known from the prior art. Especially So-called sack papers, from which, for example, sacks or bags for containing and transporting food, cement or other objects are formed, have a relatively high extensibility. Typical representatives of such sack papers and their production are described, for example, in EP 3 385 442 A1 or EP 3 211 135 B1.

As has been found, such sack papers are only suitable to a very limited extent for use as pallet outer packaging. For example, it can be established that typical sack papers tend to be damaged to a large extent in the course of the outer packaging of a pallet, in particular to tearing, which often leads to a total loss of an outer packaging and is therefore uneconomical. Cracking mainly occurs at the corners and edges of a pallet. Furthermore, with typical sack paper, damage to the corners and edges of a pallet wrapped with it can occur with too great frequency during transport of the pallet.

Furthermore, a number of requirements are placed on pallet outer packaging materials or correspondingly outer packaging pallets, which cannot be fully met by conventional sack paper. According to the EUMOS standard 40509, the industry standard for load safety, a maximum permanent deformation of 5% and a maximum elastic deformation of 10% and a shift between individual pallet layers in relation to each other must not exceed 2%. As has been found, typical sack papers cannot fully meet these requirements.

There is therefore still a need for improvement in the field of pallet outer packaging materials in the endeavor to replace plastic films as outer packaging material.

The object of the present invention was to overcome the remaining deficiencies of the prior art and to provide a pallet wrapping paper by means of which pallets, in particular so-called homogeneous pallets, can be repackaged economically and efficiently, with in particular only a small frequency of damage during outer packaging and/or transport of a pallet, and which pallet outer packaging paper is therefore generally suitable as a replacement for plastic films. It was also an object of the invention to provide an outer packaging method for pallets using such pallet outer packaging paper and a method for producing such pallet outer packaging paper. This object is achieved by a pallet wrapping paper, a pallet wrapping method and a method for producing a pallet wrapping paper according to the claims.

The pallet wrapping paper is intended in particular for wrapping homogeneous pallets.

The pallet wrapping paper has an extensibility according to ISO 1924-3:2005 of 8% to 15% in the machine direction and 8% to 15% in the cross direction.

The pallet packaging paper comprises at least 70% by weight, preferably at least 80% by weight, of cellulose fibers with a length-weighted average fiber length according to ISO 16065-2:2014 of 1.8 mm to 2.8 mm.

Furthermore, the pallet wrapping paper has a flexural strength according to ISO 2493-1:2010 using a bending angle of 15° and a test bending length of 10 mm of maximum 35 mN in the machine direction and maximum 30 mN in the transverse direction and a maximum flexural strength index of 100 Nm ⁶ / kg ³ in the machine direction and at most 80 Nm ⁶ /kg ³ in the cross direction. A grammage of the pallet packaging paper is 50 g/m ² to 90 g/m ² .

The term pallet can be understood as meaning a load made up of load objects or packaged goods which are arranged stacked on a pallet carrier. In this respect, the term pallet load or pack load can also be used for the term pallet. In no way does the term pallet mean just a pallet carrier, for example a wooden frame, for which repackaging would therefore be pointless. However, the pallet wrapping paper can also be used, for example, to wrap so-called silage bales, which silage bales are wrapped in a similar way to pallets.

As is known, the term homogeneous pallet can be understood to mean a pallet with evenly stacked load units or packaged goods, so that this stacking results in a cuboid, cube-shaped, cylindrical or polygonal pallet or pallet load. A homogeneous palette thus has corners and continuous edge extensions according to the geometric body structure of a cuboid, cube, cylinder or other body with a polygon as the base area, without significant defects in these possible geometric structures, such as holes due to missing packaged goods, being present. This is in contrast to so-called heterogeneous pallets, which have a bulky structure or shape. This shapeless structure of a heterogeneous pallet is often due to differently shaped individual packaged goods, whereas the individual packaged goods to be stacked on a homogeneous pallet usually have the same geometric shape.

For example, as is well known, the terms machine direction and cross direction correspond to the definitions in SCAN-P 9:93.

Due to the characteristics of the pallet wrapping paper, pallets, in particular homogeneous pallets, can be efficiently repackaged by hand or by machine. In particular, due to the characteristics of the pallet wrapping paper, damage to the paper can be effectively prevented during a wrapping process itself, but also during subsequent transport of a wrapped pallet. This is in contrast to typical sack paper, for which it has been found that damage often occurs, in particular tearing in the area of corners and edges of a pallet. The low flexural rigidity of the pallet packaging paper is essential here, as a result of which the formation of predetermined tear lines in the packaging paper in the area of corners and edges of a pallet can be prevented. As a result, outer packaging with a substitute material for plastic films can be provided with improved efficiency, also from an economic point of view. In addition to other influencing factors, the mechanical properties of the outer packaging paper can be significantly influenced by the choice of the longitudinally weighted average fiber length of the cellulose fibers.

Furthermore, an outer packaging paper designed in this way can provide improved temperature protection in comparison to conventional outer packaging plastic films, since outer packaging paper has comparatively better insulating properties. In addition, the outer packaging paper with the specified parameters can provide an outer packaging material with very good puncture resistance.

In a further development of the pallet overwrap paper, a ratio of the stretchability according to ISO 1924-3:2005 in the machine direction to the stretchability according to ISO 1924-3:2005 in the transverse direction of the pallet wrapping paper is 1.0 to 1.4. The extensibility in the machine direction can therefore be at least the same or up to 1.4 times greater than in the transverse direction.

With this feature, the outer packaging paper can be given improved resistance to crack formation, in particular damage to the pallet outer packaging paper can be prevented in the course of a prestressed outer packaging process.

It can also be provided in the case of the pallet outer packaging paper that a ratio of the flexural rigidity according to ISO 2493-1:2010 in the machine direction to the flexural rigidity according to ISO 2493-1:2010 in the transverse direction is 1.0 to 1.3. The flexural rigidity in the machine direction can therefore be at least the same or up to 1.3 times greater than in the transverse direction.

This feature makes it possible to prevent damage, in particular cracking in a preferred direction in the wrapping paper, both during a wrapping process and, for example, during transport of a wrapped pallet. In particular, an outer packaging paper with good flexibility can be provided, by means of which a pallet or the packaged goods on a pallet can be wrapped tightly, and a good stabilization of a pallet can thereby be achieved.

Furthermore, the pallet wrapping paper can have a tensile rupture work index according to ISO 1924-3:2005 (Tensile Energy Absorption Index, TEA Index) of 5.0 J/g to 6.5 J/g in the machine direction and of 2.7 J/g g to 3.7 J/g in the transverse direction.

Tensile rupture work indices from the specified value ranges have proven to be particularly suitable for the pallet wrapping paper, since on the one hand sufficiently good deformability and on the other hand sufficiently good tensile strength can be achieved both in the machine direction and in the transverse direction.

It can subsequently also be provided that the pallet packaging paper has a tensile strength index according to ISO 1924-3:2005 of at least 100 Nm/g in the machine direction. As a result, the pallet wrapping paper can be wrapped around a pallet or pallet load with sufficient pretension in the course of a wrapping process, in particular also by machine.

In a further development, the pallet outer packaging paper can have a wet tensile strength index according to ISO 3781:2011 of at least 10 Nm/g.

Furthermore, the pallet packaging paper can have a Cobb 1800 value according to ISO 535:2014 of at most 60 g/m ² .

As a result of these features, a pallet wrapped with the pallet wrapping paper can also be temporarily stored in a damp environment, for example, since improved resistance to moisture can be provided.

Furthermore, the pallet wrapping paper can have a tear resistance index according to ISO 1974:2012 of at least 10 mN m ² /g in the machine direction and of at least 15 mN m ² /g in the transverse direction.

This feature can provide yet another improvement in the damage resistance of the overwrap paper. The tear resistance index of the outer packaging paper can be influenced in particular by the type of pulp, in particular the fiber length of the cellulosic fibers of the pulp.

In addition, the pallet overwrap paper can have a burst index according to ISO 2758:2014 of at least 7.0 kPa m ² /g.

As has been found, a minimum bursting index as specified can effectively prevent the outer packaging paper from bursting open. The bursting index of the outer packaging paper can also be influenced by the type of pulp and the fiber length of the cellulose fibers of the pulp, but also by the additives added to the outer packaging paper.

In a further development of the pallet packaging paper, it can preferably be provided that it has a lignin content according to JAYME/KNOLLE/RAPP of 4% by weight to 12% by weight. The procedure for the gravimetric determination of the lignin content according to JAYME/KNOLLE/RAPP can JAYME G., KNOLLE H. & G. RAPP, "Development and final version of the lignin determination method according to JAYME-KNOLLE", Das Papier 12, 464 - 467 (1958), No. 17/18. The procedure described herein comprises an extraction using an extraction mixture of methanol and benzene, it being possible to use dichloromethane as the extraction agent instead, as is known per se today and is customary.

A lignin content in the specified range appears to be able to favorably influence the balance between formability and strength that is important for the use of pallet packaging paper. This is in contrast to typical sack paper, for which bleached sulphate pulp with only a very low lignin content is often used for production. In addition, this feature has an ecologically but also economically favorable effect with regard to the production of the cellulose, since a more efficient provision of the cellulose with a higher wood yield is made possible. In addition, the lignin contained in the pallet packaging paper acts as a protection against UV light, which is advantageous, for example, in the case of outdoor storage of a pallet wrapped with the packaging paper.

Furthermore, the pallet packaging paper can have a sizing agent content of 0.015% by weight to 0.04% by weight.

In addition, it can be provided that the outer packaging paper has 0.7% by weight to 1.2% by weight of starch, preferably cationic starch.

In addition, the overwrap paper may comprise from 0.05% to 0.2% by weight of a dry strength agent, preferably a glyoxalated polyacrylamide-containing dry strength agent.

The mechanical properties of the pallet outer packaging paper, in particular also the flexural strength, can also be influenced by such additives, as a result of which a more efficient wrapping of a pallet with less tendency of the outer packaging paper to form cracks can be achieved. Finally, at least one surface of the pallet wrapping paper can have micro-creping.

Among other things, this leads to improved deformability of the outer packaging paper without its strength values being negatively influenced to any great extent. Such micro-creping can be produced, for example, by means of a so-called Clupak device integrated into a paper machine, as is described, for example, in EP 3 385 442 A1 or EP 3 211 135 B1 already cited at the outset. Alternatively, a so-called Expanda® unit can also be used to achieve high extensibility in paper, as described, for example, in a review by Vishtal & Retulainen, 2014 “Extensibility review”, BioResources 9(4), 7951-8001.

The object of the invention is also achieved by an outer packaging method for pallets.

The repackaging process includes the steps

Providing a pallet, in particular a homogeneous pallet, consisting of a pallet carrier with packaged goods stacked on it

positioning the pallet in an overwrapping apparatus and wrapping the pallet with one or more layers of overwrap material.

What is essential in the outer packaging method is that a pallet outer packaging paper as described above and below is used as the outer packaging material.

The precise implementation and also the equipment used to implement the outer packaging process can be of a diverse nature, numerous outer packaging processes and equipment for performing outer packaging being known to the person skilled in the art from the prior art. In this context, purely by way of example, reference is made to EP 0 533 520 B1, JP H05310211 A, FR 2675466 A1 or DE 40 18111 A1 already cited at the outset. Of course, the repackaging process, in particular the step of wrapping a pallet, can in principle also be carried out manually.

The object of the invention is also achieved by a method for producing a pallet wrapping paper, in particular for the wrapping of homogeneous pallets. The method can be provided in particular for the production of an outer packaging paper for pallets as described above. The method comprises the steps a) providing a pulp containing, based on 100% by weight of the dry matter of the pulp, at least 70% by weight, preferably at least 80% by weight, of cellulose fibers with a length-weighted average fiber length according to ISO 16065-2:2014 of 1 .8 mm to 2.8 mm, b) production of an aqueous suspension comprising the pulp with a water content of 97% by weight to 99.85% by weight, c) applying the aqueous suspension by means of a headbox to a wire of a wire section with formation a paper web, wherein the wire is moved at a speed that is 1.5% to 6%, preferably 2% to 5% higher or lower than an application rate of the aqueous suspension to the wire, d) further processing of the paper web from step c) to form the outer packaging paper with multi-stage drying of the paper web.

The pallet wrapping paper is given an extensibility according to ISO 1924-3:2005 of 8% to 15% in the machine direction and 8% to 15% in the transverse direction, a flexural rigidity according to ISO 2493-1:2010 using a bending angle of 15° and a test bending length of 10 mm of no more than 35 mN in the machine direction and no more than 30 mN in the transverse direction and a flexural strength index of no more than 100 Nm ⁶ /kg ³ in the machine direction and no more than 80 Nm ⁶ /kg ³ in the transverse direction and a grammage of 50 g/m ² to 90 g/m ² awarded.

The specified measures can be used to produce a pallet wrapping paper with mechanical properties that are sufficient for wrapping pallets, in particular homogeneous pallets. The advantages that can be achieved with such a pallet wrapping paper have already been described above. In particular, a pallet wrapping paper can be produced with sufficiently low flexural rigidity but still sufficient strength, which has proven to be damage-resistant when wrapping a pallet, even when the wrapping paper is prestressed.

Coniferous wood, at least predominantly, can preferably be used to produce the pulp. Mixtures of several softwoods and mixtures of softwoods with deciduous trees are also fundamentally possible. For example, a mixture of 40% by weight to 50% by weight of spruce wood and From 50% to 60% by weight pine has been found beneficial in obtaining the desired lengthwise weighted average cellulosic fiber lengths specified above.

In a preferred development of the method, in step a) the cellulose, based on 100% by weight of dry matter of the cellulose, can be provided with a content of 4% by weight to 12% by weight of lignin according to JAYME/KNOLLE/RAPP.

This measure can favorably influence the balance between formability and strength, which is important for the use of pallet packaging paper. In addition, this feature has an ecologically but also economically favorable effect with regard to the production of the cellulose, since a more efficient provision of the cellulose with a higher wood yield is made possible.

An additional step a1) can be provided in the method, in which an aqueous suspension of the pulp from step a) is produced with a consistency of 25% to 40% and subjected to mechanical processing and defibration in a high-consistency defibrator to form a Schopper-Riegler value according to ISO 5267-1:1999 from 10 °SR to 18 °SR.

Such mechanical processing in the high-consistency range can be carried out, for example, with a specific grinding capacity of about 270 kWh/ton, ie about 270 kWh per ton of dry pulp pulp. Clumping of cellulose fibers can be prevented by such defibration, as a result of which a more homogeneous arrangement of the cellulose fibers in the pulp for the subsequent steps and ultimately also in the pallet outer packaging paper can be achieved. This procedural measure generally leads to improved deformability or flexibility of the outer packaging paper and thus has a favorable effect on an outer packaging process.

In addition or as an alternative, however, a method step a2) can also be provided, in which an aqueous suspension of the pulp from step a) or al) is produced with a consistency of 3% to 5% and subjected to mechanical processing and defibration in one or more low-consistency refiner(s) to a Schopper-Riegler value according to ISO 5267-1:1999 of 15 °SR to 30 °SR. In this way, too, the outer packaging paper can be given improved deformability and, at the same time, mechanical strength. Such mechanical processing in the low-consistency range can be carried out, for example, in one or more refiners with a specific total grinding capacity of around 60 kWh/t.

However, a further process step b1 can also be provided, in which 0.015 to 0.04% by weight of sizing agent is added as an additive to the aqueous suspension, based on 100% by weight of dry matter pulp.

Furthermore, it can be provided that in the process of the aqueous suspension, based on 100% by weight of dry pulp pulp, 0.7% by weight to 1.2% by weight of starch, preferably cationic starch, are admixed as an additive.

In addition, 0.05% by weight to 0.2% by weight of a dry strength agent can be added to the aqueous suspension, based on 100% by weight of dry pulp pulp. A dry strength agent containing glyoxalated polyacrylamide can preferably be added to the aqueous pulp suspension.

The mechanical properties of the pallet packaging paper, in particular the flexural strength, can also be influenced by these process measures relating to the mixing in of additives. The above information regarding amounts of additive in wt.% are not to be understood as part of the 100 wt.% dry pulp pulp, but are a respective statement in wt.% additive based or given in relation to 100 wt.% dry pulp pulp.

Usually, step d) of the method involves a multi-stage drying of the paper web, in which, as is known, first pre-drying by means of a wire section, followed by drying by means of a press section and finally drying by means of a drying section can take place.

In particular, micro-creping can be introduced into at least one surface of the paper web in the course of drying in method step d).

The formability of the pallet packaging paper can be further increased by introducing micro-creping. In particular, the extensibility of the outer packaging paper can be increased by this measure. Such a micro-crepe can, for example, be introduced into the paper web in the course of drying by means of a so-called Clupak device integrated into a paper machine, as is described, for example, in EP 3 385 442 A1 or EP 3 211 135 B1 already cited at the outset. Alternatively, a so-called Expanda® unit can also be used to provide high extensibility in paper, as described, for example, in a review by Vishtal & Retulainen, 2014 “Extensibility review”, BioResources 9(4), 7951-8001.

In particular, the specified method can impart an extensibility according to ISO 1924-3:2005 from 8% to 15% in the machine direction and from 8% to 15% in the transverse direction to the pallet wrapping paper. Furthermore, the pallet wrapping paper can preferably have a ratio of ISO 1924-3:2005 machine direction extensibility to ISO 1924-3:2005 transverse direction extensibility from 1.0 to 1.4, and independently preferably a ratio of Bending stiffness according to ISO 2493-1:2010 in the machine direction to bending stiffness according to ISO 2493-1:2010 in the transverse direction from 1.0 to 1.3. The pallet overwrapping paper can thus be given an extensibility in the machine direction which is at least as great as or up to 1.4 times greater than the extensibility in the transverse direction. Irrespective of this, the pallet outer packaging paper can be given a flexural rigidity in the machine direction which is at least the same as or up to 1.3 times greater than the flexural rigidity in the transverse direction.

In addition, the method can provide that the pallet outer packaging paper has a tensile fracture work index according to ISO 1924-3: 2005 (Tensile Energy Absorption Index, TEA Index) of 5.0 J/g to 6.5 J/g in machine direction and from 2.7 J/g to 3.7 J/g in the cross direction. The pallet wrapping paper can also be given a tensile strength index according to ISO 1924-3:2005 of at least 100 Nm/g in the machine direction. The process can also be advantageous if the pallet packaging paper has a wet tensile strength index of at least 10 Nm/g according to ISO 3781:2011 and a Cobb 1800 value according to ISO 535:2014 of at most 60 g/m ² will.

For a better understanding of the invention, it is explained in more detail with reference to the exemplary embodiments illustrated in the following figures.

They each show in a greatly simplified, schematic representation: 1 shows a detail of an exemplary embodiment of an outer packaging method using an exemplary pallet outer packaging device;

2 shows a detail of an exemplary embodiment of a headbox and a wire section of a paper machine;

3 shows a detail of an exemplary embodiment of a dryer section with a creping device of a paper machine.

As an introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numbers or the same component designations, it being possible for the disclosures contained throughout the description to be applied to the same parts with the same reference numbers or the same component designations. The position information selected in the description, such as top, bottom, side, etc., is related to the figure directly described and shown and these position information are to be transferred to the new position in the event of a change of position.

1 shows a detail of an exemplary embodiment of an outer packaging method using a typical pallet outer packaging device 1 or station. As shown, in a typical outer packaging method, a pallet 2 comprising a pallet carrier 3 with packaged goods 4 stacked thereon is provided and positioned in an outer packaging device 1 . In the embodiment shown, the pallet can be positioned on a rotatable, driven turntable 5 . The pallet 2 shown in FIG. 1 is designed as a so-called homogeneous pallet and has a cuboid shape in the illustrated embodiment. Such a pallet 2 can be wrapped with an outer packaging material 6 by rotating the turntable 5 . The outer packaging material 6 can, for example, be pulled off a roll (not shown) and arranged on the pallet 2 in a height-adjustable manner with guide mechanisms and a pretensioning device (also not shown in detail) and wound around the pallet 2 by rotating the turntable 5 as indicated in FIG. In this case, the pallet 2 can be wrapped with one or more layers of an outer packaging material 6 .

In the present invention, the outer packaging material 6 is formed by a pallet outer packaging paper 7 as described above and also below. As illustrated in FIG. 1 , the pallet wrapping paper 7 is intended in particular for the wrapping of homogeneous pallets 2 . An extensibility according to ISO 1924-3:2005 of the overwrap paper 7 is from 8% to 15% in the machine direction and from 8% to 15% in the cross direction.

The outer packaging paper 7 has at least 70% by weight, preferably at least 80% by weight, of cellulose fibers with a length-weighted average fiber length according to ISO 16065-2:2014 of 1.8 mm to 2.8 mm.

In order to achieve the best possible damage resistance, the pallet outer packaging paper 7 has a bending stiffness according to ISO 2493-1:2010 using a bending angle of 15° and a test bending length of 10 mm of a maximum of 35 mN in the machine direction and a maximum of 30 mN in the transverse direction as well as a flexural strength index of at most 100 Nm ⁶ /kg ³ in the machine direction and at most 80 Nm ⁶ /kg ³ in the transverse direction. A grammage of the outer packaging paper 7 is from 50 g/m ² to 90 g/m ² .

A ratio of ISO 1924-3:2005 machine direction extensibility to ISO 1924-3:2005 cross direction extensibility of the overwrap paper 7 may be 1.0 to 1.4. Furthermore, a ratio of the flexural stiffness according to ISO 2493-1:2010 using a bend angle of 15° and a test bend length of 10 mm in the machine direction to the flexural stiffness according to ISO 2493-1:2010 using a bend angle of 15° and a test bend length of 10 mm in the transverse direction of the overwrap paper 7 is 1.0 to 1.3. In addition, the outer packaging paper 7 can have a tensile work index according to ISO 1924-3:2005 (Tensile Energy Absorption Index, TEA Index) of 5.0 J/g to 6.5 J/g in the machine direction and 2.7 J/g up to 3.7 J/g in the transverse direction.

In particular, the overwrap paper 7 can have a tensile strength index according to ISO 1924-3:2005 of at least 100 Nm/g in the machine direction. A high tensile strength index in the machine direction is particularly desirable because when a pallet 2 is overwrapped, the overwrapping paper 7 is usually drawn off a roll in this direction and is prestressed in the machine direction. Furthermore, the pallet packaging paper 7 can have a wet tensile strength index according to ISO 3781:2011 of at least 10 Nm/g. In this context, the outer packaging paper 7 can also have a Cobb 1800 value according to ISO 535:2014 of at most 60 g/m ² .

Furthermore, the pallet wrapping paper can have a tear resistance index according to ISO 1974:2012 of at least 10 mN m ² /g in the machine direction and of at least 15 mN m ² /g in the transverse direction, as well as a bursting index according to ISO 2758:2014 of at least 7.0 kPa m ² /g.

In addition to the cellulose fibers, the outer packaging paper can have a lignin content according to JAYME/KNOLLE/RAPP of 4% by weight to 12% by weight.

In addition, the outer packaging paper 7 can have a sizing agent content, for example alkenylsuccinic anhydride (ASA), of 0.015% by weight to 0.04% by weight.

As a further additive, the outer packaging paper can contain 0.7% by weight to 1.2% by weight of starch, preferably cationic starch. In addition, the overwrap paper may comprise from 0.05% to 0.2% by weight of a dry strength agent, preferably a glyoxalated polyacrylamide-containing dry strength agent. In principle, the pallet outer packaging paper can also contain other additives customary in paper technology in small proportions, alum being mentioned purely by way of example, which, for example, accounts for a proportion of 0.02% by weight to 0.08% by weight in the outer packaging paper can be included.

Finally, at least one surface of the wrapping paper 7 can have micro-creping.

A method for producing pallet wrapping paper 7, in particular for wrapping homogeneous pallets, can fundamentally be carried out in or by means of a paper machine. The basic structure and the basic operations in such a paper machine are known to the person having ordinary skill in the technical field of paper manufacture. Therefore, only a brief summary of the process for producing the pallet wrapping paper is described below, with some process steps be explained in more detail. The method can be provided in particular for the production of a pallet wrapping paper as described above.

As is known per se, the method comprises providing a pulp as step a). In the present method, the pulp provided in step a) has, based on 100% by weight dry matter of the pulp, at least 70% by weight, preferably at least 80% by weight, cellulose fibers with a length-weighted average fiber length according to ISO 16065-2:2014 of 1.8mm to 2.8mm. The pulp is preferably sulfate pulp, also referred to as Kraft pulp, the pulp preferably being produced from coniferous wood, such as spruce wood and/or pine wood, using the so-called Kraft process.

With regard to the desired mechanical properties of the outer packaging paper, it can be quite advantageous if, in one embodiment of the method for its production in step a), the cellulose, based on 100% by weight of dry matter of the cellulose, has a content of 4% by weight to 12% by weight of lignin according to JAYME/KNOLLE/RAPP.

A further process step al) can also be useful, in which an aqueous suspension of the pulp from step a) is produced with a consistency of 25% to 40% and subjected to mechanical processing and defibration in a high-consistency defibrator to a Schopper-Riegler value from 10°SR to 18°SR. In such mechanical high-consistency processing or defibration, an energy input can be, for example, 230 kWh/ton of dry pulp mass to 310 kWh/ton of dry pulp mass, in particular about 270 kWh/ton of dry pulp mass.

In addition to or independently of such a process step al), a process step a2) can also be useful, in which an aqueous suspension of the pulp from step a) or al) is produced with a consistency of 3% to 5% and mechanical processing and defibration in is subjected to one or more low-consistency refiners to a Schopper-Riegler value of 15°SR to 30°SR. With such mechanical processing of the pulp at low consistency, a total energy input can be, for example, 30 kWh/ton of dry pulp mass to 90 kWh/ton of dry pulp pulp, in particular about 60 kWh/ton of dry pulp pulp. For introducing the cellulose into a paper machine, in a further process step b) the production of an aqueous suspension comprising the cellulose with a water content of 97% by weight to 99.85% by weight is provided. If necessary, this can be done after mechanical processing according to steps a1) and/or a2) specified above. A pH of this aqueous suspension can be 5-7, for example.

In this case, provision can certainly be made for customary additives to be added to the pulp suspension.

In particular, it can be provided that 0.015% by weight to 0.04% by weight of sizing agent is added to the aqueous suspension 8 in a step b1), based on 100% by weight of dry matter pulp.

Furthermore, it can be provided that in the process of the aqueous suspension, based on 100% by weight of dry pulp pulp, 0.7% by weight to 1.2% by weight of starch, preferably cationic starch, are added.

In addition, 0.05% by weight to 0.2% by weight of a dry strength agent, based on 100% by weight of dry pulp pulp, can be added to the aqueous suspension. A dry strength agent containing glyoxalated polyacrylamide can preferably be added to the aqueous pulp suspension.

In addition, other additives customary in paper technology can also be added in small proportions to the aqueous pulp suspension.

The specification of the respective range limits in wt the % by weight of additive is given based on or in relation to 100% by weight of dry pulp pulp.

In a subsequent step c), the suspension produced in step b) is introduced into a paper machine. As illustrated in FIG. 2, the suspension 8 of the cellulose can be applied or applied from a storage container 9 or intermediate storage container for the cellulose suspension 8 to a rotating screen 10 of a screen section 11 . This as usual via a nozzle-like inlet 12 with outlet opening 13. By uniform When the aqueous pulp suspension 8 is discharged onto the screen 10 , a paper web 14 is formed on the screen 10 .

As is known per se, the mere process of application to the screen 10 results in at least partial alignment of the highly anisotropic cellulose fibers in the aqueous pulp suspension. This orientation of the fibers can be influenced both in terms of orientation and extent of orientation by the choice of application parameters, such as the consistency of the applied pulp suspension 8, but also, for example, by the feed speed of the screen 10 relative to the application speed of the pulp suspension. The type and extent of the orientation of the cellulose fibers subsequently also influence the properties of the resulting paper after further processing with drying of the paper web in the following, further sections of the paper machine.

To produce the pallet wrapping paper with the properties specified above, which makes the same suitable for use as pallet wrapping paper, it has proven to be advantageous for the SieblO to have a 1.5% to 6%, preferably 2% to 5% higher or lower speed than an application rate of the aqueous pulp suspension 8 onto the wire 10. A paper machine for the production of the pallet wrapping paper can preferably be provided with a Fourdrinier wire, in particular a Fourdrinier wire section.

However, it should be mentioned at this point that the properties of the resulting pallet packaging paper can also be influenced by other production parameters with regard to the desired mechanical properties. For example, as already indicated, the mechanical properties can be influenced by the type of pulp itself, for example by the selection of the wood species(s) used to produce the pulp. In the present case, softwoods can preferably be used to produce the pulp; in particular, a weight proportion of softwoods can be at least 80% by weight.

Furthermore, the mechanical properties of the pallet packaging paper can also be influenced by adding various additives to the aqueous pulp suspension. Examples of preferred additives have already been given above in this description. The mechanical properties of the resulting pallet packaging paper can also be influenced by the further process control or the further processing of the paper web in the paper machine.

After the pulp suspension 8 has been applied in method step c), in a further method step d) the paper web 14 is further processed into the outer packaging paper with multi-stage drying of the paper web. The successive drying of the paper web 14 can take place here as usual by means of a wire section 11, subsequently with a press section and finally by means of a drying section of a paper machine, as is generally known to the person skilled in the art.

In particular, in the course of method step d), micro-creping can be introduced into at least one surface of the paper web 14 . Such micro-creping can, for example, be introduced into the paper web 14 by means of a creping device 15 as it passes through a drying section 16, as is illustrated with reference to FIG. In Fig. 3 a part of a drying section 16 of a paper machine is shown in detail. The creping device 15 can be formed, for example, by a so-called Clupak system or Clupak unit 17 . As is known per se, when using a Clupak unit 17, microcreping is introduced by compressing the paper web between a circulating cloth and a cylinder, as is also described, for example, in EP 3 211 135 B1 mentioned at the outset.

Such a creping device 15 or Clupak unit 17 can be arranged in the course of a drying section 16 . In particular, a creping device 15 or Clupak system 17, as illustrated in FIG. As is known per se, the compression of the paper web 14 in a Clupak unit 17 can be achieved by selecting a lower take-off speed by means of the after-drying section 19 than a feed speed from the pre-drying section 18 into the Clupak unit 17 .

As an alternative to the Clupak unit 17 shown in Fig. 3, a so-called Expanda® unit can also be used as a creping device, for example, as for example in a review by Vishtal & Retulainen, 2014 "Extensibility review", BioResources 9(4), 7951 -8001 is described.. Ultimately, it is essential in the manufacturing process for a pallet wrapping paper that the pallet wrapping paper has an extensibility according to ISO 1924-3:2005 of 8% to 15% in the machine direction and 8% to 15% in the transverse direction, a flexural rigidity according to ISO 2493- 1:2010 using a bending angle of 15° and a test bending length of 10 mm of not more than 35 mN in the machine direction and not more than 30 mN in the transverse direction, a bending strength index of not more than 100 Nm ⁶ /kg ³ in the machine direction and not more than 80 Nm ⁶ /kg ³ in Transverse direction and a grammage of 50g/m ² to 90 g/m ² can be awarded. Within the specified ranges of these parameters, the paper in question has proven to be suitable as pallet wrapping paper. Outside the specified ranges of parameters, there was a greater tendency for mechanical integrity failure, reducing the suitability of papers with corresponding parameters outside of the specified ranges.

Furthermore, the pallet wrapping paper can preferably have a ratio of stretchability according to ISO 1924-3:2005 in the machine direction to stretchability according to ISO 1924-3:2005 in the transverse direction of 1.0 to 1.4, and independently preferably a ratio of the bending stiffness according to ISO 2493-1:2010 machine direction to ISO 2493-1:2010 transverse direction bending stiffness of 1.0 to 1.3.

In addition, the method can provide that the pallet outer packaging paper has a tensile fracture work index according to ISO 1924-3:2005 (Tensile Energy Absorption Index, TEA Index) of 5.0 J/g to 6.5 J/g in machine direction and from 2.7 J/g to 3.7 J/g in the cross direction. The pallet wrapping paper can also be given a tensile strength index according to ISO 1924-3:2005 of at least 100 Nm/g in the machine direction. The process can also be advantageous if the pallet packaging paper has a wet tensile strength index of at least 10 Nm/g according to ISO 3781:2011 and a Cobb 1800 value according to ISO 535:2014 of at most 60 g/m ² will.

The exemplary embodiments show possible variants, whereby it should be noted at this point that the invention is not limited to the specifically illustrated variants of the same, but rather that various combinations of the individual variants with one another are also possible and this possibility of variation is based on the teaching on technical action through the present invention in skills of the specialist working in this technical field. The scope of protection is determined by the claims. However, the description and drawings should be used to interpret the claims. Individual features or combinations of features from the different exemplary embodiments shown and described can represent independent inventive solutions. The task on which the independent inventive solutions are based can be found in the description.

All information on value ranges in the present description should be understood to include any and all sub-ranges, e.g. the information 1 to 10 should be understood to mean that all sub-ranges, starting from the lower limit 1 and the upper limit 10, are also included , ie all subranges start with a lower limit of 1 or greater and end with an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

Finally, for the sake of clarity, it should be pointed out that some elements are shown not to scale and/or enlarged and/or reduced in size for a better understanding of the structure.

List of reference numbers Pallet packaging device Pallet Pallet carrier Packed goods Turntable Packaging material Pallet packaging paper Pulp suspension Storage container Wire Wire section Inlet Outlet opening Paper web Creping device Drying section Clupak unit Pre-drying section After-drying section

Claims

- 23 -Claims

1. Pallet packaging paper, in particular for the packaging of homogeneous pallets, with an extensibility according to ISO 1924-3:2005 of 8% to 15% in the machine direction and 8% to 15% in the transverse direction, characterized in that it contains at least 70% by weight % comprises cellulosic fibers having a length-weighted mean fiber length according to ISO 16065-2:2014 from 1.8 mm to 2.8 mm, and that it has a bending stiffness according to ISO 2493-1:2010 using a bend angle of 15° and a test bend length of 10 mm of not more than 35 mN in the machine direction and not more than 30 mN in the transverse direction and a flexural strength index of not more than 100 Nm ⁶ /kg ³ in the machine direction and not more than 80 Nm ⁶ /kg ³ in the transverse direction and a grammage of 50 g/m ² to 90 g/ m ² .

2. Outer wrapping paper according to claim 1, characterized in that a ratio of the stretchability according to ISO 1924-3:2005 in the machine direction to the stretchability according to ISO 1924-3:2005 in the transverse direction is 1.0 to 1.4.

3. Outer wrapping paper according to claim 1 or 2, characterized in that a ratio of the flexural rigidity according to ISO 2493-1:2010 in the machine direction to the flexural rigidity according to ISO 2493-1:2010 in the transverse direction is 1.0 to 1.3.

4. Outer packaging paper according to one of the preceding claims, characterized in that it has a tensile rupture work index according to ISO 1924-3: 2005 (Tensile Energy Absorption Index, TEA Index) of 5.0 J/g to 6.5 J/g in the machine direction and from 2.7 J/g to 3.7 J/g in the transverse direction.

5. Outer wrapping paper according to one of the preceding claims, characterized in that it has a tensile strength index according to ISO 1924-3:2005 of at least 100 Nm/g in the machine direction.

6. Outer packaging paper according to one of the preceding claims, characterized in that it has a wet tensile strength index according to ISO 3781:2011 of at least 10 Nm/g.

7. Outer packaging paper according to one of the preceding claims, characterized in that it has a Cobb 1800 value according to ISO 535:2014 of at most 60 g/m ² .

8. Outer packaging paper according to any one of the preceding claims, characterized in that it has a tear resistance index according to ISO 1974:2012 of at least

10 mN m ² /g in the machine direction and at least 15 mN m ² /g in the cross direction.

9. Outer packaging paper according to one of the preceding claims, characterized in that it has a bursting index according to ISO 2758:2014 of at least 7.0 kPa m ² /g.

10. Outer packaging paper according to one of the preceding claims, characterized in that it has a lignin content according to JAYME/KNOLLE/RAPP of 4% by weight to 12% by weight.

11. Wrapping paper according to any one of the preceding claims, characterized in that at least one surface has micro-creping.

12. Pallet overwrapping method comprising the steps

Positioning the pallet in an overwrapping device and wrapping the Pallet with one or more layers of an outer packaging material, characterized in that a pallet outer packaging paper according to one of Claims 1 to 11 is used as the outer packaging material.

13. A method for producing a pallet wrapping paper, in particular for the wrapping of homogeneous pallets, in particular for producing a pallet wrapping paper according to any one of claims 1 to 11, comprising the steps a) providing a cellulose having, based on 100 wt.% Dry matter of the pulp, at least 70% by weight cellulose fibers with a length-weighted average fiber length according to ISO 16065-2:2014 of 1.8 mm to 2.8 mm, b) production of an aqueous suspension comprising the pulp with a water content of 97% by weight to 99.85% by weight, c) application of the aqueous suspension by means of a headbox to a rotating screen of a screen section to form a paper web, the screen being moved at a speed that is uml.5% to 6% higher or lower than an application rate of the aqueous suspension on the screen, d) further processing of the paper web from step c) to the outer packaging paper under multi-stage Troc bending of the paper web, whereby the pallet wrapping paper has an extensibility according to ISO 1924-3:2005 from 8% to 15% in the machine direction and from 8% to 15% in the transverse direction, a bending stiffness according to ISO 2493-1:2010 using a bending angle of 15° and a test bending length of 10 mm of no more than 35 mN in the machine direction and no more than 30 mN in the transverse direction, a bending strength index of no more than 100 Nm ⁶ /kg ³ in the machine direction and no more than 80 Nm ⁶ /kg ³ in the transverse direction and a grammage of 50 g/m ² to 90 g/m ² is imparted. - 26 -

14. The method according to claim 13, characterized in that in step a) the pulp, based on 100% by weight dry matter of the pulp, is provided with a content of 4% by weight to 12% by weight of lignin according to JAYME/KNOLLE/RAPP will.

15. The method according to claim 13 or 14, characterized in that in a step al) an aqueous suspension of the pulp from step a) with a consistency of 25% to 40% is produced and mechanical processing and defibration in a high-consistency defibrator into one Schopper-Riegler value according to ISO 5267-1:1999 from 10 °SR to 18 °SR.

16. The method according to any one of claims 13 to 15, characterized in that in a step a2) an aqueous suspension of the pulp from step a) or al) is produced with a consistency of 3% to 5% and mechanical processing and defibration in one or more low-consistency refiner(s) to a Schopper-Riegler value according to ISO 5267-1:1999 from 15 °SR to 30 °SR.

17. The method according to any one of claims 13 to 16, characterized in that in a step bl) the aqueous suspension, based on 100% by weight of dry matter pulp, 0.015% by weight to 0.04% by weight of sizing agent is added.

18. The method according to any one of claims 13 to 17, characterized in that in a step b2) the aqueous suspension, based on 100% by weight dry matter pulp, 0.7% by weight to 1.2% by weight starch are added.

19. The method according to any one of claims 13 to 18, characterized in that in a step b3) the aqueous suspension, based on 100% by weight of dry matter pulp, 0.05% by weight to 0.2% by weight of a dry strength agent is added .

20. The method according to any one of claims 13 to 19, characterized in that in the course of step d) a micro-crepe is introduced into at least one surface of the paper web.