EP4166715B1 - Packaging material and banderole made therefrom - Google Patents

Description

The present invention relates to a packaging material consisting of an unbleached kraft paper with a kappa value according to ISO 302:2015 between 38 and 60, preferably between 40 and 58 as base material, wherein the kraft paper is made of at least 90% primary pulp and has a basis weight according to ISO 536:2019 between 65 g/m ² and 170 g/m ² , as well as to a banderol made from such a packaging material, a method for producing the same and a use of the packaging material.

Unbleached kraft paper is widely used as a packaging material because of its high resistance to tearing and its good stability against moisture and chemicals. Regardless of whether it is bleached or unbleached, kraft paper is also easy to print on, so that the necessary information printed directly on the packaging is visible to the consumer. A typical application for kraft paper, and especially unbleached kraft paper, is in the production of bags for packaging a wide variety of materials, such as building materials, sharp-edged materials, food, toys, and the like. In the packaging sector, however, there is not only the form of packaging in which the goods to be packaged are completely wrapped in packaging paper, such as bags closed on all sides. It is also often possible to simply surround the goods to be packaged or goods to be sold in bundles with a type of ribbon on which information about the contents, shelf life, etc., and often also brand names, is printed. Such loops are often also used to hold together a plurality of similar or different related goods to be packaged. In the clothing sector, for example, several goods, such as a plurality of T-shirts, socks or the like, are often packaged simply by surrounding them with a loop or banderol. It is essential for the packaging material from which such a loop is made that it tightly encloses the goods to be packaged or enclosed so that the loop cannot be accidentally pulled down, one or more of the products enclosed by the loop cannot fall out and it is further guaranteed that the goods to be enclosed by the loop can, on the one hand, be inserted into the loop without damage and, on the other hand, that the loop surrounding the goods does not tear or become damaged in any other way during such insertion or subsequent transport, handling or the like.

In the same way, it is often necessary to provide tubular packaging materials into which compressible or resilient objects can be packed in their most must be packaged in a compressed form in order to, on the one hand, keep the space required for this packaging as small as possible and, on the other hand, to ensure that the packaged goods are not compressed and decompressed unnecessarily often during transport, which could lead to material fatigue. In this context, it is particularly important that the packaging material is not stressed beyond its stretchability by the tensile stress exerted by the resilient goods packaged therein and does not tear, or that the tubular packaging material is not damaged when the goods to be packaged are inserted. Plastic films or tapes have been considered most suitable for this purpose to date. These can be produced in various designs and can also be adapted to the respective requirements. For environmental reasons, the aim is to replace plastic packaging as far as possible with packaging made from materials derived from renewable raw materials. Recently, there has been increased research into producing specialty papers, particularly kraft papers, which meet a wide range of requirements in terms of durability, stretchability, moisture resistance, and the like, in order to replace plastic packaging. Particularly in cases where ring-shaped, closed tubes or loops have to be used as packaging materials, the problem arises that, for example, paper packaging is made from a flat paper web, which web has to be glued or otherwise sealed in some other way to form the ring or tube. If this closure is only closed after the goods to be packaged have been inserted, the time required for a formed adhesive joint to harden or dry may be too long for mass production, so that, similar to plastic packaging, it is necessary to form this tube, ring, or loop before the products it is to enclose are inserted. In order to ensure that products can be inserted into such a tube, ring or loop without damaging the tube or loop itself, such packaging material or packaging paper must not only have excellent stretchability in the radial direction, i.e. in the circumferential direction of the ring or loop, but must also not tear at the edges, especially when inserting the items. WO2021/053186 describes a kraft paper suitable for sack paper.

The US 2020/290321 describes a kraft paper for packaging.

The WO 2021/186282 describes a wrapping paper.

The present invention therefore aims to provide a packaging material made of unbleached kraft paper which does not tear in the machine longitudinal direction or cross-machine direction under high loads, in particular a load that stretches the paper, and which is or remains sufficiently elastic or resilient over time so that the objects packed therein do not suffer from a loss of tension or elasticity even after a long time. of the packaging material can fall out.

To achieve this object, the packaging material according to the invention is essentially characterized in that it contains at least 90% primary pulp, containing at least 80%, preferably at least 85%, in particular at least 88% pulp with an average length-weighted fiber length according to ISO 16065-2:2014 between 2.0 mm and 2.9 mm and less than 5%, preferably less than 4.5%, in particular less than 4.2% fillers as well as cationic starch and other processing aids, that the primary pulp is contained as ground, in particular high-consistency ground pulp with a Schopper-Riegler freeness according to ISO 5267-1:1999 between 13 °RS to 20 °RS, that it has a starch content of 0.5% to 2.2% of the paper, in particular of 0.7% to 2.0%, that it has an elongation at break ratio MD/CD according to ISO 1924-3:2005 of ≥ 1.1, a tear length in the machine direction according to ISO 1924-3:2005 of ≥ 10 km and that a tear resistance index in the transverse direction (CD) according to ISO 1974:2012 is ≥ 16.0 mN.m ² /g. The fact that the unbleached kraft paper of the packaging material has an elongation at break ratio MD/CD according to ISO 1974:2012 of ≥ 1.1 ensures that its extensibility in the machine direction (MD) is greater than that in the transverse direction and that the packaging material is therefore not only extensible in MD and CD, but can be subjected to a greater change in length in one direction than in the other without having to fear destruction, in particular tearing, of the packaging material.

Because the packaging material contains at least 90% primary pulp, containing at least 80%, preferably at least 85%, in particular at least 88% pulp with an average length-weighted fiber length according to ISO 16065-2:2014 between 2.0 mm and 2.9 mm, as well as less than 5%, preferably less than 4.5%, in particular less than 4.2% fillers, as well as cationic starch and other processing aids, it is possible to provide an unbleached kraft paper with an extremely tear-resistant structure and, in particular due to the narrow fiber length distribution of the primary pulp used, to achieve excellent homogeneous paper properties in both the machine direction and the cross direction. Due to its durability and its ability to be (micro)creped in a Clupak system, such unbleached kraft paper can also be used safely and reliably for packaging sharp-edged objects or heavy materials, such as cement or beverage bottles. By further containing less than 5%, preferably less than 4.5%, in particular less than 4.2% (the percentages stated are always to be understood as weight percent in the context of the present invention) fillers as well as cationic starch and processing aids, it is possible to simultaneously obtain a resistant but not excessively stiff unbleached kraft paper in which high percentages of starch, in particular cationic starch, due to the lignin remaining in the kraft paper and the hemicelluloses remaining in the kraft paper and the associated high numbers of negative charges can be used. Since unbleached kraft paper produced in this way is not overly stiff, but extremely stretchable, it is possible, particularly when bows, banderoles or tubes are made from this packaging material, to securely and reliably enclose the items packaged therein without having to worry about them accidentally slipping out of the packaging material. When producing such tubes or bows, care must be taken to ensure that the unbleached kraft paper has a greater stretchability in the winding direction of the bow than in the transverse direction of the loop.

By designing the packaging material such that it has a starch content of 0.5% to 2.2% of the kraft paper, in particular 0.7% to 2.0%, the excellent mechanical properties of the unbleached kraft paper succeed in maintaining the surface smoothness of at least one side of the kraft paper and keeping the Bendtsen roughness low, thus providing excellent printability on this at least one side of the packaging material. In the present context, an attempt is simultaneously made to make only one side, in particular the side facing away from the machine or "top side," of the paper correspondingly smooth in order to maximize the adhesion of the packaging material according to the present invention to the inside of tubular or ring-shaped packages, i.e., the side facing away from the "top side," in order to minimize the loss of the items packaged therein due to slipping.

By, as corresponds to a further development of the invention, the packaging material is designed in such a way that the primary pulp is contained as ground, in particular high-consistency ground pulp with a Schopper-Riegler freeness level according to ISO 5267-1:1999 between 13 °SR and 20 °SR, it is possible to break up any remaining fiber agglomerates, such as strips and splinters, whereby a uniform sheet or particularly homogeneous kraft paper can be formed in which an optimized combination between flexibility of the fiber and tear resistance index in the transverse direction can be achieved. It goes without saying that by grinding paper to a high or low consistency both the tear length and the air permeability of the paper can be adjusted, although the latter is not important in the present case, especially in the case of an optional application of coatings, since neither rapid filling of closed bags made of the packaging material according to the present invention is to be achieved, nor does the air permeability otherwise result in advantageous or negative properties for packaging made from the packaging material.

The fact that the elongation at break ratio MD/CD according to ISO 1974:2012 is ≥ 1.1 further ensures that even objects that do not have a homogeneous, uniform, or smooth surface can be safely and reliably packaged in this packaging material based on unbleached kraft paper. This is because the paper, essentially after it has returned to its original shape from its expanded form upon insertion of the goods, tightly encloses the packaged goods on all sides and is also capable of safely and reliably holding goods with uneven surfaces. At the same time, the elongation is sufficiently large so that the products can be inserted into the paper without damaging it, in particular into tubular sleeves formed from this paper. Furthermore, it is ensured that the paper returns to its original shape after the materials have been inserted and stretched, tightly enclosing the packaged objects. This means that there is no need to fear that packaged objects will fall out of, for example, tubular or ring-shaped packages made from the packaging material according to the invention. Furthermore, it has been shown that with an elongation at break ratio MD/CD according to ISO 1974:2012 of > 3, no further improvement in the properties of the packaging material required for packaging heavy objects can be achieved.

The fact that the tear length in the machine direction according to ISO 1924-3:2005 is ≥ 10 km further ensures that the machine strength in the longitudinal direction of the packaging material is so great that, even if, for example, tubular or ring-shaped packaging has been made from it, even non-flexible objects can be inserted into the interior of this packaging material formed in this way without having to fear accidental tearing of the kraft paper. Furthermore, since the tear resistance index in the transverse direction according to ISO 1974:2012 is ≥ 16.0 mN.m ² /g, it is ensured that there is no risk of a free edge of the packaging material tearing, even in the event of unintentionally high loads on the edge of the packaging material. In particular, when tubular or ring-shaped products are made from this packaging material, such as bows or banderoles, there is no risk of the packaging material tearing and thus destruction of the packaging when the goods to be packaged are inserted.

By designing the packaging material in such a way that a tear resistance index in the transverse direction (CD) according to ISO 1974:2012 is ≥ 16.0 mN.m ² /g, the packaging material, which essentially consists of unbleached kraft paper, can also be subjected to heavy loads at its edges without the risk of tearing or tearing of the paper from the edge to the center. Ultimately, this can prevent even a small If a crack is formed in the packaging material, it will not accidentally enlarge.

In the context of the present invention, the term "packaging material" refers essentially to unbleached kraft paper, which may optionally be coated on one or both sides. Furthermore, it may comprise one or more layers of kraft paper.

According to a further development, the packaging material can also be made of 100% primary pulp. By making the packaging material, especially the unbleached kraft paper, 100% primary pulp, negative influences on the final product, such as those caused by recycled pulp or pulp obtained from waste paper, can be even more reliably avoided. In particular, this prevents the reduced strength or elongation of the packaging material, which is usually caused by waste paper or recycled pulp. In connection with the present invention, it is essential that in particular the elongation at break or the elongation at break ratio, the tear length in the machine direction and the tear resistance index in the transverse direction can be kept high and as constant as possible over time in order to provide consistent material properties with which it is possible to produce tubular packaging or banderoles in which even heavy or sharp-edged objects can be packaged and/or wrapped and stored for a longer period of time without there being any risk of the unbleached kraft paper tearing or tearing and of the packaging produced therewith deteriorating.

According to a further development of the invention, the packaging material is designed such that the primary pulp consists of a mixture consisting of at least 80% softwood pulp, more preferably at least 90% softwood pulp, in particular at least 95% softwood pulp with an average length-weighted fiber length according to ISO 16065-2:2014 of at least 2.0 mm, preferably at least 2.2 mm, and the remainder hardwood pulp with an average length-weighted fiber length according to ISO 16065-2:2014 of at least 1.0 mm. Due to the predominant amount of softwood pulp with an average length-weighted fiber length according to ISO 16065-2:2014 of at least 2.0 mm and the rest of hardwood pulp with an average length-weighted fiber length according to ISO 16065-2:2014 of at least 1.0 mm, the strength properties of at least one side of the unbleached kraft paper can be positively influenced by the softwood pulp and the smoothness by the hardwood pulp, and a targeted choice of the pulp composition can produce a packaging material with both excellent mechanical properties, especially elongation at break ratio, and sufficient smoothness, which provides good printability Furthermore, with such a choice of pulp mixture, in particular the high content of softwood pulp, it can be ensured that an unbleached packaging material produced in this way has a large tear length in the machine direction, whereby a particularly resilient packaging material can be provided in which even objects with a higher weight can be packaged without the packaging necessarily having to have a bottom and/or top surface.

By designing the packaging material in such a way that it has a tensile strength index in the machine direction according to ISO 1924:3: 2005 of ≥ 105 Nm/g, preferably at least 115 Nm/g, as is the case with a further development of the invention, non-destructive packaging of even heavy or sharp-edged objects in the packaging material according to the present invention is ensured. The tensile strength index in the machine direction according to the invention further ensures that, when producing, for example, tubular packaging or loop-shaped or banderol-shaped packaging from the packaging material according to the invention, it is possible to provide sufficient resilience of the packaging material, whereby even heavy objects can be reliably fitted into such a loop or banderol made of the packaging material and, moreover, there is no risk of the material tearing.

Likewise, as is the case with a further development of the invention, the packaging material has a TEA index in the machine direction according to ISO 1924-3:2005 of greater than 5.0 J/g, preferably greater than 5.5 J/g. Because the TEA index in the machine direction is greater than 5.0 J/g, it is possible to provide a packaging material that is extremely elastic and stretchable without the packaging material tearing. The TEA index is understood to mean the tensile energy absorption index ("Tensible Energy Absorption Index") according to ISO 1924-3:2005.

In order to reliably prevent the packaging material according to the invention from tearing or bursting from the edges to the center, the invention is further developed such that the packaging material has a bursting strength according to ISO 2758:2014 of greater than 750 kPa, preferably greater than 770 kPa, and particularly preferably greater than 800 kPa. According to the invention, the bursting strength is adjusted or increased, among other things, by a combination of the following measures: use of softwood pulp, a low filler content, and a high proportion of, for example, cationic starch. Furthermore, refining, in particular low-consistency refining, also has a positive influence on the bursting strength.

By designing the packaging material in such a way that it has a wet strength index according to ISO 3781:2011 in the machine direction of at least 14.0 Nm/g, in particular 14.5 Nm/g, particularly preferably at least 15.0 Nm/g, as corresponds to a further development of the invention, it is possible to provide, in particular, tubular or ring-shaped packaging with the packaging material, which is also suitable for use in humid environments. In particular, when, for example, food packaging or loops that surround and hold together a plurality of foodstuffs or foodstuffs are made from the packaging material, contact with condensation, moisture or a humid environment is unavoidable, so that a high wet strength or a high wet strength index, but without having to use permanent wet strength agents or large quantities thereof, is desirable in the production of the packaging material, which essentially consists of unbleached kraft paper.

Surprisingly, such high wet strength can also be achieved with high dry strength using the packaging material according to the present invention. Typically, achieving high wet strength requires the use of larger amounts of auxiliary materials, such as wet strength agents, which in turn pose problems when recycling the packaging material to be produced, which essentially consists of unbleached kraft paper. Since the dry strength, expressed by the tensile strength index in the machine direction, of the packaging material according to the invention, which essentially consists of unbleached kraft paper, is ≥ 105 Nm/g, sufficient wet strength can be achieved in a surprisingly resource-efficient manner without, or only by adding, very small amounts of wet strength agents.

In this case, wet strength agents are understood to be water-miscible polymer solutions in the processed state, which are primarily produced from polyamines and epichlorohydrin derivatives. Urea-formaldehyde or melamine-formaldehyde-based products are also conceivable as wet strength agents, but these are no longer used to avoid health risks. When the wet strength agents react with cellulose fibers, cross-links form between the fibers, which lead to increased water resistance of the corresponding paper produced in this way. However, the hydrophobic linkage thus formed prevents easy or successful recycling of paper treated with these wet strength agents. Therefore, returning used packaging paper to a pulp cycle is not possible or only possible to a limited extent due to the use of high temperatures and/or additional chemicals and additives. It is therefore desirable to keep the amount of wet strength agents used as low as possible, which surprisingly can be realized with a paper or packaging material according to the invention.

The invention further aims to design or provide a banderol from the packaging material according to the present invention, with which banderol it is possible to package or enclose a plurality of heavy, unconnected products and to transport them without having to fear that the packaging material will tear.

To achieve this object, according to the invention, a banderol made of the packaging material of the present invention is provided, which is designed such that it is formed from a paper web made essentially of unbleached kraft paper that is closed, in particular crimped, glued, preferably twice glued, welded, stapled, sewn or riveted in the transverse direction, and that a machine direction of the paper web forms a circumferential direction of the banderol. Because the paper web is formed from a transversely sealed, in particular crimped, glued, preferably twice glued, welded, stapled, sewn or riveted, essentially made of unbleached kraft paper, it is possible to provide the greater stretch that the unbleached kraft paper has in the machine direction in the circumferential direction of the banderol or the tubular packaging, so that due to the excellent stretchability of the packaging material in the machine direction, even a plurality of objects does not tear or further tear the packaging material when inserted into the banderol or into the packaging material glued to form a ring. Since it is thus possible to enclose a plurality of objects with the banderol, it is of course possible to enclose and hold together several objects, whether similar or different, without the need for packaging that completely surrounds the objects. By arranging the packaging material in the finished band in such a way that a machine direction of the packaging material forms a circumferential direction of the band, the stretch properties in the machine direction introduced by the manufacturing process of the packaging material can be used to ensure that objects to be packaged or enclosed can be inserted into a band that has already been glued to form a ring, using the stretch properties of the packaging material, without there being any risk of the band tearing and are held firmly in this ring after they have been inserted due to the resilience of the packaging material.

By connecting the packaging material into a ring, loop, or banderol that encloses a plurality of items in the machine direction of the paper web, it is also possible to insert the majority of items into such a banderol without fear of the banderol tearing in the transverse or longitudinal direction, or at the edges. It goes without saying that such a banderol represents an extremely paper-saving type of packaging, with which items can be packaged and held together safely and reliably.

By enclosing at least two identical or different objects, the band ensures that any size of container can be formed. Due to the MD/CD elongation at break ratio according to ISO 1924-3:2005 of ≥ 1.1 to approximately 3 and the tear resistance index in the transverse direction according to ISO 1974:2012 of ≥ 16.0 mN.m ² /g, these containers can be reliably inserted into the band or the tubular product without there being any risk of the paper edges tearing or being torn out. Even heavy objects or objects that are long or tall compared to the width of the band can be packaged in such a band without there being any risk of the band tipping over and subsequently tearing. This is because, due to the material properties of the packaging material, the objects can be tightly enclosed and therefore there is no risk of the banderol tearing and subsequently being torn even if one or more objects are tipped over.

The band can be designed such that the plurality of objects are arranged in several rows, circularly, or forming a dense package within the band. With such an arrangement of the enclosed objects, for example, conventional beverage packages comprising two, six, or even twelve bottles can be surrounded by a band according to the invention, or food products such as zucchini or bananas can be arranged in a band, or even several identical foam elements, such as foam cushions or metal or wooden rods, can be arranged inside such a band.

According to a further development of the invention, the band is designed such that it is subjected to tensile stress by the enclosed objects, in particular to a tensile stress that is less than the elongation at break in the machine direction (MD) of the paper web, measured according to ISO 1924-3:2005. The tensile stress of the objects packaged inside such a band ensures that an object does not accidentally fall out of the banderol, which would subsequently mean that the stability of the remaining products could no longer be guaranteed.

In order to provide sufficient stretchability of the packaging material and also to be able to provide sufficient recovery, the packaging material is essentially designed so that the elongation at break in the machine direction (MD) of the paper web, measured according to ISO 1924-3:2005, is ≥ 8%. Kraft papers, which have an elongation at break of the paper web of ≥ 8% in the machine direction, have proven themselves in standard packaging materials, such as heavy-duty bags and the like, which are subjected to heavy loads in the MD. Surprisingly, it has been shown that bands made from such a material are able to hold packaged products securely and reliably due to the excellent recovery capacity of this material, without there being any risk of the products slipping or falling out of the band, or of the band tearing or ripping when inserting the products.

A further object of the present invention is to provide a method for forming a band from the packaging material according to the invention. Due to conventional manufacturing processes, the problem essentially lies in the fact that, due to appropriate treatments, a paper web generally exhibits greater stretch properties in the machine direction than in the transverse direction. Although isotropic papers are already known that exhibit identical properties in the longitudinal and transverse directions, their production on large paper machines is limited, and in particular, these papers typically exhibit at least slightly poorer properties in the transverse direction.

In order to optimally utilize the favorable properties of the packaging material according to the invention in a banderol, the method according to the invention is designed such that a length of packaging material slightly exceeding a circumference of the banderol to be formed is cut from a web of packaging material consisting essentially of unbleached kraft paper unrolled in the longitudinal direction of the machine, the cut-off length of packaging material is pivoted by 90°, those two free edges of the cut-off length which run in the cross-machine direction when the web of packaging material is unrolled are folded over one another and sealed to form a tube, and that a plurality of banderoles are severed from the sealed tube or prepared for separation, in particular perforated, scored or marked. Due to the impossibility or economic futility of making cuts or a plurality of cuts in the paper in the longitudinal direction of the machine in an unwinding paper web on a paper machine, the method is Essentially, a length of packaging material is first cut from an unrolling web of packaging material, which length essentially corresponds to the circumference of a banderol to be produced. A certain excess length can of course be provided here, which must be present as an overlap of the material when the layer of packaging material is subsequently closed to form a tube or, if necessary, a single banderol. After the corresponding length has been cut off, a tube can either be formed directly from the cut length, with the paper then being folded together in such a way that in principle the transverse direction, i.e. the width of the web of packaging material, forms the circumferential length of the tube, or the cut piece of packaging material can be turned directly by 90° and then glued, crimped, riveted, sewn or similarly connected to form a tube. In a final step, it is now necessary to cut off corresponding pieces, which correspond to the width of the banderol, from the tube thus formed. Separation can be achieved by cutting, punching, tearing, and the like. This can be done either by pre-perforating, marking lines, pre-punching areas, or similar processes. Depending on the intended use and final use of the band, this can be done either immediately or at the end customer's site. It makes sense not to separate those pieces that form multiple bands, as printing, for example, is generally easier if larger areas can be printed simultaneously.

According to a further development of the method according to the invention, the method can be carried out such that the pivoting of the cut length of packaging material by 90° is carried out before or after the two free edges of the cut length that run in the cross-machine direction during unwinding of the web of packaging material are folded over and sealed. As explained above, it is irrelevant whether the pivoting of the cut length of packaging material by 90° is carried out before or after the two free bands of the cut length are folded over to seal them.

The packaging material according to the invention can, as corresponds to a further development of the invention, be used as a banderol, whereby it should not go unmentioned that, of course, conventional bags and the like could also be made from this packaging material, although this only seems sensible for high-performance products due to the special material properties.

• Fig. 1 eine schematische Darstellung von möglichen Arten der Verbindung von einem Verpackungsmaterial gemäß der Erfindung zu einer Banderole bzw. Schleife; und
• Fig. 2 eine schematische Darstellung des Verfahrensablaufs zur Herstellung einer Banderole aus dem Verpackungsmaterial gemäß der Erfindung.

The invention is further explained below with reference to exemplary embodiments and drawings. These show:

• Fig. 1 a schematic representation of possible ways of connecting a packaging material according to the invention to a banderol or loop; and
• Fig. 2 a schematic representation of the process sequence for producing a banderol from the packaging material according to the invention.

In detail, Fig. 1a ) schematically shows a banderol or loop 1, which banderol 1 is designed such that two free ends 2, 3 of the packaging material forming the banderol 1 overlap and at least one connection is formed in the area of the overlap 4.

With such a packaging material 1, which is designed in particular as a loop or band, it is thus possible to hold a plurality of objects of the same or different configurations by means of the band 1, without, for example, having to use additional plastic packaging that extends over the entire package of the objects. The area of the connection 4 can have any type of connection, such as, for example, flat adhesives (see Fig. 1b )), point-shaped bonding (see Fig. 1c )), or it can be any type of connection, such as sewing (see Fig. 1d )), brims, large-area gluing, or similar methods can be used. A band constructed in this way is then pulled over the objects to be held together, whereby the objects are held together tightly and firmly due to the resilience of the material.

In Fig. 1b ) is a perspective longitudinal view of an endless tube formed from the packaging material according to the invention, which endless tube 1 is intended for forming a plurality of banderoles 1. In the Fig. 1b ), the free ends 2, 3 of the packaging material are again arranged overlapping and the connecting area 4 is glued over its entire surface, as shown by a dashed area. The dashed lines 11 show in Fig. 1b ) possible dividing lines for separating individual banderoles 1.

In Fig. 1c ) is a representation of an endless tube made of the packaging material according to the invention in an analogous manner to that in Fig. 1b ), where instead of a full-surface bonding in the overlapping area, 4 point-shaped bonding points were implemented, which are arranged in two offset rows. It is unnecessary to note that that of course any other type of bonding can be chosen, be it in two individual bonding lines, one bonding line or the like.

In Fig. 1d ), which also contains a representation like in Fig. 1b ) of the packaging material according to the invention, it is shown that the free ends 2, 3 of the packaging material forming the endless tube are sewn to a second layer of the packaging material 8, as is schematically indicated by the seam lines 6.

With such bands 1, it is now possible to package a wide variety of objects together in a captive manner and, in particular, to ensure that tearing of the packaging material 8 is avoided, even when heavy objects, such as metal rods or the like, are packaged. When such a band 1 is pulled over objects to be packaged, in particular heavy or hard objects, the resilience of the unbleached kraft paper forming it, in particular its elongation at break, tensile strength or tear resistance index, ensures that if a small tear should form in the packaging material 8 forming the band 1, this tear will not tear further and, moreover, the band 1 thus formed contracts sufficiently after stretching to ensure that the objects packaged therein can also slip out after packaging is completed. In addition, due to the special design of the packaging material 8, a certain degree of static friction can be exerted on the objects packaged therein, ensuring that the objects are immovably held inside the banderol 1 and that individual or multiple objects are reliably prevented from slipping out. The static friction mentioned here can be exerted not only by the banderol 1, but also, for example, by the surface of the objects packaged therein.

In Fig. 2 , in which the reference numerals of Fig. 1 are retained, the process sequence for producing a banderol from the packaging material 8 according to the invention is shown schematically.

In Fig. 2 7 denotes a roll of packaging material 8, as it is wound onto a reel during production, for example, from a paper machine. The packaging material 8 is unwound from the roll 7 of packaging material 8 in the direction of arrow 9, which arrow 9 also corresponds to the machine direction of the machine on which the packaging material 8 was produced, for example, a paper machine. Once a sufficient length of packaging material 8 has been unwound, it is cut off along the width of the packaging material 8, as indicated by dashed line 10. In a second step, this cut-off length of packaging material 8 is turned by 90°, as indicated by arrow 11, in order to have the original machine direction 9 now arranged in the transverse direction of the cut-off piece of packaging material 8, as again indicated by arrow 9. The cut-off piece of packaging material 8 has a length L in the machine direction of the roll of packaging material 8, which essentially corresponds to the circumference of a band 1 to be formed from this packaging material 8, wherein, depending on the subsequent method of joining the packaging material 8, either a slight excess length is selected in order to be able to glue the ends over one another, or in principle the exact circumferential length of the band is selected if the connection is made by crimping, clamping, sewing or the like. In a third step, a tube is formed from this severed length of packaging material 8, wherein any conventional tube forming method can be used here, as indicated in the figure. In the present case, the tube is formed such that the free ends 2, 3 of the packaging material 8 overlap each other by a distance or a length 4, in order to subsequently be able to glue the free ends 2, 3 together, for example, in particular even to glue them twice. The free ends of the packaging material 8 are, as shown in the Fig. 1 designated by the reference numerals 2 and 3 and the overlapping piece with 4, as shown for example in Fig. 1a is shown. After gluing the packaging material 8, the tube thus produced can either be printed or subjected to any further treatment, such as perforating, marking, punching or, in particular, cutting, in order to produce the banderoles 1 according to the invention from the material.

It goes without saying that the second step of the process of folding the packaging material 8 by 90° can also be performed after the tube forming process. In any case, the packaging material 8 must be joined together along the edges 2, 3 in order to ensure that the favorable material properties resulting from the machine direction of production are available in the circumferential direction of a finished banderol 1.

With regard to the optional process steps, such as printing, perforating, or the like, it should be noted that these can be performed before or after any step following the separation of the web of packaging material 8 from the drum. Thus, it may be advantageous to print directly on the separated piece of packaging material and only then form a tube from the packaging material 8.

The banderole or bow 1 can not only be single-coloured, but also printed in multiple colours, with company wording, logos and the like, and moreover, it can have a one-sided or two-sided coating, for example, to improve the moisture resistance of the packaging material 8. Finally, it can also have more than one layer of unbleached kraft paper. In this case, it should be noted that the essential properties of the band 1 must not be altered, and neither the elongation at break nor the bursting strength, the tear length, etc., must be adversely affected.

Finally, it goes without saying that a banderol 1 according to the invention can be used not only to hold heavy and hard objects or plastic containers together, but also, for example, to surround socks and to bind together foodstuffs such as bananas, zucchini, cucumbers, or the like. Goods packaged in cans, such as foodstuffs, boxes, and the like, can also be bound together.

Furthermore, the invention is explained in more detail using exemplary embodiments.

Example 1: Production of a packaging material based on unbleached kraft paper with a grammage of 82 g/m ² Process description:

An unbleached pulp consisting of 100% primary softwood pulp (a blend of spruce and pine) with a kappa number of 51 was first subjected to high-consistency refining at a refining capacity of 230 to 240 kWh/t, with the pulp's freeness after high-consistency refining being 17°SR. This pulp was then subjected to low-consistency refining at a refining capacity of 90 to 100 kWh/t. The following additives were added to the approach flow system of the paper machine. The pH was adjusted to a pH of 6.8 to 7.0 with aluminum sulfate. Cationic starch with a cationization degree DS of 0.03 was added at a rate of 17 kg/t of dry paper. Alkenylsuccinic anhydride was used as a sizing agent at a rate of 0.8 kg/t of dry kraft paper, and 10 kg/t of PAAE was used as a wet strength agent. No fillers were added. The consistency of the pulp at the headbox was 0.19%. Dewatering took place on a Foudrinier wire section and in a press section with three nips, one of which could be a shoe press. The line pressure at the three nips was 60 kN/m, 90 kN/m, or 500 kN/m (in the shoe press). Before the still moist paper was fed into the Clupak system, it was subjected to contact drying, conventional drying with hot air at 167 °C, then pre-dried in a slalom drying section and treated in a Clupak system with a differential speed of -7.9% and finally dried to a final residual moisture content of 7.5%.

The kraft paper can be used as such for the production of bows or banderoles and the paper properties described in the table below were measured in this kraft paper.

The kraft paper produced in this way had the following properties: Table 1: Paper properties standard Unit Direction Result Grammage ISO 536:2019 g/ ^m2 82 Tensile strength ISO 1924-3:2005 kN/m MD 8.9 Tensile strength index ISO 1924-3:2005 Nm/g MD 109 Tensile strength ISO 1924-3:2005 kN/m CD 5.4 Tensile strength index ISO 1924-3:2005 Nm/g CD 66.3 Elongation at break ISO 1924-3:2005 % MD 9.6 Elongation at break ISO 1924-3:2005 % CD 8.6 Tensile fracture work ISO 1924-3:2005 J/m ² MD 578 Tensile fracture work ISO 1924-3:2005 J/m ² CD 405 Bendtsen roughness ISO 8791-2:2013 ml/min Top 867 Bendtsen roughness ISO 8791-2:2013 ml/min bottom 1250 Burst strength ISO 2758:2014 kPa 781 Wet strength index ISO 3781:2011 Nm/g MD 15.2 Tear resistance index ISO 1974:2012 mN.g/m ² MD 14.2 Tear resistance index ISO 1974:2012 mN.g/m ² CD 16.1 Ratio of elongation at break ISO 1924-3:2005 - MD/CD 1.12 Tear length ISO 1924-3:2005 km MD 11.06

Example 2: Production of a packaging material based on unbleached kraft paper with a grammage of 130 g/m ² Process description:

An unbleached pulp consisting of 95% primary softwood pulp with a kappa number of 41 and 5% primary hardwood pulp with a kappa number of 40 was first subjected to high consistency refining with a refining capacity of 190 to 210 kWh/t. The pulp had a freeness of 19 °SR after high-consistency refining, and this pulp was then subjected to low-consistency refining with a refining capacity of 70 to 80 kWh/t. The auxiliaries were added in the approach flow system of the paper machine. The pH was adjusted to a pH of 6.8 to 7.0 using aluminum sulfate. Cationic starch with a cationization degree DS of 0.03 was added at a rate of 14 kg/t of dry paper, and alkenylsuccinic anhydride was used as a sizing agent at a rate of 0.8 kg/t of dry kraft paper. Glycoxalated PAM was used as a wet strength agent at 10 kg/t of dry kraft paper. No fillers were added. The consistency of the pulp at the headbox was 0.23%. Dewatering took place on a Foudrinier wire section and a press section with three nips, one of which could be a shoe press. The line pressure at the three nips was 60 kN/m, 90 kN/m, and 500 kN/m (in the shoe press), respectively. The kraft paper was pre-dried and then treated in a Clupak system with a differential speed of -8.6% and finally dried to a final moisture content of 7.5%.

The kraft paper can be used as such and the paper properties described in the table below were measured using this paper.

The kraft paper produced in this way had the following properties: Table 2: Paper properties standard Unit Direction Result Grammage ISO 536:2019 g/ ^m2 130 Tensile strength ISO 1924-3:2005 kN/m MD 16.2 Tensile strength index ISO 1924-3:2005 Nm/g MD 124.6 Tensile strength ISO 1924-3:2005 kN/m CD 6.3 Tensile strength index ISO 1924-3:2005 Nm/g CD 48.5 Elongation at break ISO 1924-3:2005 % MD 10.3 Elongation at break ISO 1924-3:2005 % CD 8.5 Tensile fracture work ISO 1924-3:2005 J/m ² MD 871 Tensile fracture work ISO 1924-3:2005 J/m ² CD 372 Bendtsen roughness ISO 8791-2:2013 ml/min Top 1420 Bendtsen roughness ISO 8791-2:2013 ml/min bottom 1890 Burst strength ISO 2758:2014 kPa 812 Wet strength index ISO 3781:2011 Nm/g MD 16.1 Tear resistance index ISO 1974:2012 mN.g/m ² MD 12.1 Tear resistance index ISO 1974:2012 mN.g/m ² CD 19.3 Ratio of elongation at break ISO 1924-3:2005 - MD/CD 1.21 Tear length ISO 1924-3:2005 km MD 12.7

Example 3: Production of a packaging material based on unbleached kraft paper with a grammage of 130 g/m ² Process description:

An unbleached pulp consisting of 95% primary softwood pulp with a kappa number of 41 and 5% primary hardwood pulp with a kappa number of 40 was first subjected to high-consistency refining at a refining capacity of 190 to 210 kWh/t. The pulp's freeness after high-consistency refining was 19 °SR. This pulp was then subjected to low-consistency refining at a refining capacity of 70 to 80 kWh/t. The additives were added in the approach flow system of the paper machine. The pH was adjusted to a pH of 6.8 to 7.0 with aluminum sulfate. Cationic starch with a degree of cationization DS of 0.03 was added at a rate of 14 kg/t of dry paper, and alkenylsuccinic anhydride was used as a sizing agent at a rate of 0.8 kg/t of dry kraft paper. Glycoxalated PAM was used as a wet strength agent at 10 kg/t of dry kraft paper. No other fillers were added. The consistency of the pulp at the headbox was 0.23%. Dewatering took place on a Foudrinier wire section and in a press section with three nips, one of which could be a shoe press. The line pressure at the three nips was 60 kN/m, 90 kN/m, or 500 kN/m (in the shoe press). The kraft paper is pre-dried and then treated in a Clupak plant with a differential speed of -8.6% and finally dried to a final moisture content of 7.5%.

The kraft paper can be used as such and the paper properties described in the table below were measured using this paper.

The kraft paper produced in this way had the following properties: Table 3: Paper properties standard Unit Direction Result Grammage ISO 536:2019 g/ ^m2 130 Tensile strength ISO 1924-3:2005 kN/m MD 16.2 Tensile strength index ISO 1924-3:2005 Nm³ / g MD 124.6 Tensile strength ISO 1924-3:2005 kN/m CD 6.3 Tensile strength index ISO 1924-3:2005 Nm/g CD 48.5 Elongation at break ISO 1924-3:2005 % MD 10.3 Elongation at break ISO 1924-3:2005 % CD 8.5 Tensile fracture work ISO 1924-3:2005 J/m ² MD 871 Tensile fracture work ISO 1924-3:2005 J/m ² CD 372 Bendtsen roughness ISO 8791-2:2013 ml/min Top 1420 Bendtsen roughness ISO 8791-2:2013 ml/min bottom 1890 Burst strength ISO 2758:2014 kPa 812 Wet strength index ISO 3781:2011 Nm/g MD 16.1 Tear resistance index ISO 1974:2012 mN.g/m ² MD 12.1 Tear resistance index ISO 1974:2012 mN.g/m ² CD 19.3 Ratio of elongation at break ISO 1924-3:2005 - MD/CD 1.21 Tear length ISO 1924-3:2005 km MD 12.7

Example 4: Production of a packaging material based on unbleached kraft paper with a grammage of 161 g/m ² Process description:

An unbleached pulp consisting of 100% primary softwood pulp with a kappa number of 46 was first subjected to high-consistency refining at a refining capacity of 210 to 220 kWh/t. The pulp's freeness after high-consistency refining was 18 °SR. This pulp was then subjected to low-consistency refining at a refining capacity of 70 to 85 kWh/t. The auxiliaries were added in the approach flow system of the paper machine. The pH was adjusted to a pH of 6.8 to 7.0 using aluminum sulfate. Cationic starch with a cationization degree DS of 0.05 was added at a rate of 12 kg/t of dry kraft paper. Alkenylsuccinic anhydride was used as a sizing agent at a rate of 0.8 kg/t of dry kraft paper. Furthermore, talc was added as a filler in a quantity of 2 kg/t kraft paper dry. The consistency of the pulp at the headbox was 0.25%. Dewatering took place on a A Foudrinier wire section, similar to a press section with three nips, with line pressures at the three nips of 60 kN/m, 80 kN/m, and 80 kN/m, respectively. The kraft paper was pre-dried, then fed to the Clupak line and subjected to a differential speed of -10.9%, then finally dried to a final residual moisture content of 8%.

The kraft paper can be used as such and the paper properties described in the table below were measured using this kraft paper.

The paper produced in this way had the following properties: Table 3: Paper properties standard Unit Direction Result Grammage ISO 536:2019 g/ ^m2 161 Tensile strength ISO 1924-3:2005 kN/m MD 19.1 Tensile strength index ISO 1924-3:2005 Nm/g MD 118.6 Tensile strength ISO 1924-3:2005 kN/m CD 7.9 Tensile strength index ISO 1924-3:2005 Nm/g CD 49.1 Elongation at break ISO 1924-3:2005 % MD 12.7 Elongation at break ISO 1924-3:2005 % CD 9.0 Tensile fracture work ISO 1924-3:2005 J/m ² MD 1007 Tensile fracture work ISO 1924-3:2005 J/m ² CD 461 Bendtsen roughness ISO 8791-2:2013 ml/min Top 1970 Bendtsen roughness ISO 8791-2:2013 ml/min bottom 2480 Burst strength ISO 2758:2014 kPa 903 Wet strength index ISO 3781:2011 Nm/g MD 15.8 Tear resistance index ISO 1974:2012 mN.g/m ² MD 12.7 Tear resistance index ISO 1974:2012 mN.g/m ² CD 20.6 Ratio of elongation at break ISO 1924-3:2005 - MD/CD 1.41 Tear length ISO 1924-3:2005 km MD 12.1

It goes without saying that the kraft papers according to the invention can also be calendered, for example, in a soft-nip or long-nip calender, or can also be subjected to a coating treatment, such as a dispersion coating treatment. However, such further treatments must not affect the essential properties of the packaging material, such as elongation at break, Bendtsen roughness, Tear length, tear resistance index, tensile strength index must not be changed. In this regard, it should be noted that additional treatment steps such as coating and calendering must not change the tear length, tear resistance index, etc., and in particular must not worsen them. If a bow or band is also made from the packaging material, care must be taken to ensure that the packaging material is arranged in such a way that the original machine direction is aligned so that it allows an increase in diameter or stretching of up to 20% of the band or loop when the band is subjected to stretching. By applying a coating, if necessary, to one or both sides of the band, the way in which the free ends of the packaging material forming the bow or band are connected can be changed. Without a coating, the free ends can be connected by gluing, staples, crimping, sewing, or similar. For packaging materials coated on one side, a bonding process using hot-melt adhesive, hot-melt, or similar materials can also be provided. For packaging materials coated on both sides, direct bonding of two coating layers can be provided, which can be achieved with extremely little time, but may be disadvantageous for environmental reasons. The same applies to multi-layer packaging materials.

Claims (12)

1. Packaging material (1) consisting of an unbleached kraft paper with a Kappa number according to ISO 302:2015 between 38 and 60, preferably between 40 and 58 as base paper, wherein the kraft paper is manufactured from at least 90 % primary cellulose and has a grammage according to ISO 536:2019 between 65 g/m² and 170 g/m², characterized in that it contains at least 90 % primary cellulose, containing at least 80 %, preferably at least 85 %, in particular at least 88 % cellulose with a length-weighted mean fibre length according to ISO 16065- 2:2014 between 2.0 mm and 2.9 mm and less than 5 %, preferably less than 4.5 %, in particular less than 4.2 % fillers as well as cationic starch and other process aids, that the primary cellulose is contained in the form of beaten cellulose, in particular, high-consistency refined cellulose having a Schopper-Riegler degree of refining according to ISO 5267-1:1999 between 13 °SR and 20 °SR, that it has a starch content of 0.5 % to 2.2 % of the paper, in particular 0.7 % to 2.0 %, that it has a strain at break ratio MD/CD according to ISO 1924-3:2005 of ≥ 1.1, a tear length in the machine direction according to ISO 1924-3:2005 of ≥10 km, and a tear index in the cross direction according to ISO 1974:2012 of ≥16.0 mN.m²/g.
2. Packaging material (1) according to Claim 1, characterized in that the primary cellulose consists of a mixture consisting of at least 80 % softwood cellulose, preferably at least 90 % softwood cellulose, in particular at least 95 % softwood cellulose with a length-weighted mean fibre length according to ISO 16065-2:2014 of at least 2.0 mm, preferably at least 2.2 mm and the remainder of hardwood cellulose with a length-weighted mean fibre length according to ISO 16065-2:2014 of at least 1.0 mm.
3. Packaging material (1) according to Claim 1 or 2, characterized in that it has a tensile strength index in the machine direction according to ISO 1924:3-2005 of ≥ 105 Nm/g, preferably at least 115 Nm/g.
4. Packaging material (1) according to one of Claims 1, 2 or 3, characterized in that it has a TEA index in the longitudinal direction according to ISO 1924-3:2005 greater than 5.0 J/g, preferably greater than 5.5 J/g.
5. Packaging material (1) according to one of Claims 1 to 4, characterized in that it has a bursting strength according to ISO 2758:2014 of greater than 750 kPa, preferably greater than 770 kPa, particularly preferably greater than 800 kPa.
6. Packaging material (1) according to one of Claims 1 to 5, characterized in that it has a wet strength index according to ISO 3781:2011 in the machine direction of at least 14.0 Nm/g, in particular 15.2 Nm/g, particularly preferably at least 15.5 Nm/g.
7. Sleeve (1) made from a packaging material (1) according to any one of Claims 1 to 6, characterized in that it is made of a closed, in particular crimped, glued, preferably double-glued, welded, stapled, sewn or riveted in the cross direction, substantially unbleached kraft paper, and that a machine direction of the paper web forms a circumferential direction of the sleeve.
8. Sleeve (1) according to Claim 7, characterized in that it is subjected to tension by enclosed objects (5), in particular with a tensile stress which is smaller than an elongation at break in the machine direction (MD) measured in accordance with ISO 1924-3:2005 of the paper web.
9. Sleeve (1) according to Claim 7 or 8, characterized in that the elongation at break in the machine direction (MD) measured according to ISO 1924-3:2005 of the paper web is ≥8 %.
10. Method for forming a sleeve from a packaging material according to one of Claims 1 to 6, characterized in that a length of the packaging material slightly exceeding the circumference of the sleeve to be formed is cut off from a web of the packaging material substantially consisting of unbleached kraft paper that is unrolled in the machine longitudinal direction is, the cut length of the packaging material is pivoted by 90°, those two free edges of the cut length, which run in the cross-machine direction when the web of packaging material is unrolled, are folded over one another and closed to form a tube and that a plurality of sleeves are separated from the closed tube or prepared for separation, in particular perforated, scored or marked.
11. Method according to Claim 10, characterized in that pivoting the cut length of the packaging material by 90° is carried out before or after folding over and closing those two free edges of the cut length which run in the cross-machine direction when the web of packaging material is unrolled.
12. Use of a sleeve produced from the packaging material according to one of Claims 1 to 6 for tightly enclosing a plurality of objects that are the same or different from one another.

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